1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jvmtifiles/jvmtiEnv.hpp"
36 #include "memory/gcLocker.inline.hpp"
37 #include "memory/metaspaceShared.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "memory/universe.inline.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/objArrayOop.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/symbol.hpp"
44 #include "prims/jvm_misc.hpp"
45 #include "prims/jvmtiExport.hpp"
46 #include "prims/jvmtiThreadState.hpp"
47 #include "prims/privilegedStack.hpp"
48 #include "runtime/arguments.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/deoptimization.hpp"
51 #include "runtime/fprofiler.hpp"
52 #include "runtime/frame.inline.hpp"
53 #include "runtime/init.hpp"
54 #include "runtime/interfaceSupport.hpp"
55 #include "runtime/java.hpp"
56 #include "runtime/javaCalls.hpp"
57 #include "runtime/jniPeriodicChecker.hpp"
58 #include "runtime/memprofiler.hpp"
59 #include "runtime/mutexLocker.hpp"
60 #include "runtime/objectMonitor.hpp"
61 #include "runtime/osThread.hpp"
62 #include "runtime/safepoint.hpp"
63 #include "runtime/sharedRuntime.hpp"
64 #include "runtime/statSampler.hpp"
65 #include "runtime/stubRoutines.hpp"
66 #include "runtime/task.hpp"
67 #include "runtime/thread.inline.hpp"
68 #include "runtime/threadCritical.hpp"
69 #include "runtime/threadLocalStorage.hpp"
70 #include "runtime/vframe.hpp"
71 #include "runtime/vframeArray.hpp"
72 #include "runtime/vframe_hp.hpp"
73 #include "runtime/vmThread.hpp"
74 #include "runtime/vm_operations.hpp"
75 #include "services/attachListener.hpp"
76 #include "services/management.hpp"
77 #include "services/memTracker.hpp"
78 #include "services/threadService.hpp"
79 #include "trace/tracing.hpp"
80 #include "trace/traceMacros.hpp"
81 #include "utilities/defaultStream.hpp"
82 #include "utilities/dtrace.hpp"
83 #include "utilities/events.hpp"
84 #include "utilities/preserveException.hpp"
85 #include "utilities/macros.hpp"
86 #ifdef TARGET_OS_FAMILY_linux
87 # include "os_linux.inline.hpp"
88 #endif
89 #ifdef TARGET_OS_FAMILY_solaris
90 # include "os_solaris.inline.hpp"
91 #endif
92 #ifdef TARGET_OS_FAMILY_windows
93 # include "os_windows.inline.hpp"
94 #endif
95 #ifdef TARGET_OS_FAMILY_bsd
96 # include "os_bsd.inline.hpp"
97 #endif
98 #if INCLUDE_ALL_GCS
99 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
100 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
101 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
102 #endif // INCLUDE_ALL_GCS
103 #ifdef COMPILER1
104 #include "c1/c1_Compiler.hpp"
105 #endif
106 #ifdef COMPILER2
107 #include "opto/c2compiler.hpp"
108 #include "opto/idealGraphPrinter.hpp"
109 #endif
110
111 #ifdef DTRACE_ENABLED
112
113 // Only bother with this argument setup if dtrace is available
114
115 #ifndef USDT2
116 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
117 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
118 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
119 intptr_t, intptr_t, bool);
120 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
121 intptr_t, intptr_t, bool);
122
123 #define DTRACE_THREAD_PROBE(probe, javathread) \
124 { \
125 ResourceMark rm(this); \
126 int len = 0; \
127 const char* name = (javathread)->get_thread_name(); \
128 len = strlen(name); \
129 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
130 name, len, \
131 java_lang_Thread::thread_id((javathread)->threadObj()), \
132 (javathread)->osthread()->thread_id(), \
133 java_lang_Thread::is_daemon((javathread)->threadObj())); \
134 }
135
136 #else /* USDT2 */
137
138 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
139 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
140
141 #define DTRACE_THREAD_PROBE(probe, javathread) \
142 { \
143 ResourceMark rm(this); \
144 int len = 0; \
145 const char* name = (javathread)->get_thread_name(); \
146 len = strlen(name); \
147 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
148 (char *) name, len, \
149 java_lang_Thread::thread_id((javathread)->threadObj()), \
150 (uintptr_t) (javathread)->osthread()->thread_id(), \
151 java_lang_Thread::is_daemon((javathread)->threadObj())); \
152 }
153
154 #endif /* USDT2 */
155
156 #else // ndef DTRACE_ENABLED
157
158 #define DTRACE_THREAD_PROBE(probe, javathread)
159
160 #endif // ndef DTRACE_ENABLED
161
162
163 // Class hierarchy
164 // - Thread
165 // - VMThread
166 // - WatcherThread
167 // - ConcurrentMarkSweepThread
168 // - JavaThread
169 // - CompilerThread
170
171 // ======= Thread ========
172 // Support for forcing alignment of thread objects for biased locking
173 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
174 if (UseBiasedLocking) {
175 const int alignment = markOopDesc::biased_lock_alignment;
176 size_t aligned_size = size + (alignment - sizeof(intptr_t));
177 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
178 : AllocateHeap(aligned_size, flags, CURRENT_PC,
179 AllocFailStrategy::RETURN_NULL);
180 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
181 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
182 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
183 "JavaThread alignment code overflowed allocated storage");
184 if (TraceBiasedLocking) {
185 if (aligned_addr != real_malloc_addr)
186 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
187 real_malloc_addr, aligned_addr);
188 }
189 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
190 return aligned_addr;
191 } else {
192 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
193 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
194 }
195 }
196
197 void Thread::operator delete(void* p) {
198 if (UseBiasedLocking) {
199 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
200 FreeHeap(real_malloc_addr, mtThread);
201 } else {
202 FreeHeap(p, mtThread);
203 }
204 }
205
206
207 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
208 // JavaThread
209
210
211 Thread::Thread() {
212 // stack and get_thread
213 set_stack_base(NULL);
214 set_stack_size(0);
215 set_self_raw_id(0);
216 set_lgrp_id(-1);
217
218 // allocated data structures
219 set_osthread(NULL);
220 set_resource_area(new (mtThread)ResourceArea());
221 DEBUG_ONLY(_current_resource_mark = NULL;)
222 set_handle_area(new (mtThread) HandleArea(NULL));
223 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
224 set_active_handles(NULL);
225 set_free_handle_block(NULL);
226 set_last_handle_mark(NULL);
227
228 // This initial value ==> never claimed.
229 _oops_do_parity = 0;
230
231 // the handle mark links itself to last_handle_mark
232 new HandleMark(this);
233
234 // plain initialization
235 debug_only(_owned_locks = NULL;)
236 debug_only(_allow_allocation_count = 0;)
237 NOT_PRODUCT(_allow_safepoint_count = 0;)
238 NOT_PRODUCT(_skip_gcalot = false;)
239 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
240 _jvmti_env_iteration_count = 0;
241 set_allocated_bytes(0);
242 _vm_operation_started_count = 0;
243 _vm_operation_completed_count = 0;
244 _current_pending_monitor = NULL;
245 _current_pending_monitor_is_from_java = true;
246 _current_waiting_monitor = NULL;
247 _num_nested_signal = 0;
248 omFreeList = NULL ;
249 omFreeCount = 0 ;
250 omFreeProvision = 32 ;
251 omInUseList = NULL ;
252 omInUseCount = 0 ;
253
254 #ifdef ASSERT
255 _visited_for_critical_count = false;
256 #endif
257
258 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
259 _suspend_flags = 0;
260
261 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
262 _hashStateX = os::random() ;
263 _hashStateY = 842502087 ;
264 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
265 _hashStateW = 273326509 ;
266
267 _OnTrap = 0 ;
268 _schedctl = NULL ;
269 _Stalled = 0 ;
270 _TypeTag = 0x2BAD ;
271
272 // Many of the following fields are effectively final - immutable
273 // Note that nascent threads can't use the Native Monitor-Mutex
274 // construct until the _MutexEvent is initialized ...
275 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
276 // we might instead use a stack of ParkEvents that we could provision on-demand.
277 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
278 // and ::Release()
279 _ParkEvent = ParkEvent::Allocate (this) ;
280 _SleepEvent = ParkEvent::Allocate (this) ;
281 _MutexEvent = ParkEvent::Allocate (this) ;
282 _MuxEvent = ParkEvent::Allocate (this) ;
283
284 #ifdef CHECK_UNHANDLED_OOPS
285 if (CheckUnhandledOops) {
286 _unhandled_oops = new UnhandledOops(this);
287 }
288 #endif // CHECK_UNHANDLED_OOPS
289 #ifdef ASSERT
290 if (UseBiasedLocking) {
291 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
292 assert(this == _real_malloc_address ||
293 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
294 "bug in forced alignment of thread objects");
295 }
296 #endif /* ASSERT */
297 }
298
299 void Thread::initialize_thread_local_storage() {
300 // Note: Make sure this method only calls
301 // non-blocking operations. Otherwise, it might not work
302 // with the thread-startup/safepoint interaction.
303
304 // During Java thread startup, safepoint code should allow this
305 // method to complete because it may need to allocate memory to
306 // store information for the new thread.
307
308 // initialize structure dependent on thread local storage
309 ThreadLocalStorage::set_thread(this);
310 }
311
312 void Thread::record_stack_base_and_size() {
313 set_stack_base(os::current_stack_base());
314 set_stack_size(os::current_stack_size());
315 // CR 7190089: on Solaris, primordial thread's stack is adjusted
316 // in initialize_thread(). Without the adjustment, stack size is
317 // incorrect if stack is set to unlimited (ulimit -s unlimited).
318 // So far, only Solaris has real implementation of initialize_thread().
319 //
320 // set up any platform-specific state.
321 os::initialize_thread(this);
322
323 #if INCLUDE_NMT
324 // record thread's native stack, stack grows downward
325 address stack_low_addr = stack_base() - stack_size();
326 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this,
327 CURRENT_PC);
328 #endif // INCLUDE_NMT
329 }
330
331
332 Thread::~Thread() {
333 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
334 ObjectSynchronizer::omFlush (this) ;
335
336 // stack_base can be NULL if the thread is never started or exited before
337 // record_stack_base_and_size called. Although, we would like to ensure
338 // that all started threads do call record_stack_base_and_size(), there is
339 // not proper way to enforce that.
340 #if INCLUDE_NMT
341 if (_stack_base != NULL) {
342 address low_stack_addr = stack_base() - stack_size();
343 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this);
344 #ifdef ASSERT
345 set_stack_base(NULL);
346 #endif
347 }
348 #endif // INCLUDE_NMT
349
350 // deallocate data structures
351 delete resource_area();
352 // since the handle marks are using the handle area, we have to deallocated the root
353 // handle mark before deallocating the thread's handle area,
354 assert(last_handle_mark() != NULL, "check we have an element");
355 delete last_handle_mark();
356 assert(last_handle_mark() == NULL, "check we have reached the end");
357
358 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
359 // We NULL out the fields for good hygiene.
360 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
361 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
362 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
363 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
364
365 delete handle_area();
366 delete metadata_handles();
367
368 // osthread() can be NULL, if creation of thread failed.
369 if (osthread() != NULL) os::free_thread(osthread());
370
371 delete _SR_lock;
372
373 // clear thread local storage if the Thread is deleting itself
374 if (this == Thread::current()) {
375 ThreadLocalStorage::set_thread(NULL);
376 } else {
377 // In the case where we're not the current thread, invalidate all the
378 // caches in case some code tries to get the current thread or the
379 // thread that was destroyed, and gets stale information.
380 ThreadLocalStorage::invalidate_all();
381 }
382 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
383 }
384
385 // NOTE: dummy function for assertion purpose.
386 void Thread::run() {
387 ShouldNotReachHere();
388 }
389
390 #ifdef ASSERT
391 // Private method to check for dangling thread pointer
392 void check_for_dangling_thread_pointer(Thread *thread) {
393 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
394 "possibility of dangling Thread pointer");
395 }
396 #endif
397
398
399 #ifndef PRODUCT
400 // Tracing method for basic thread operations
401 void Thread::trace(const char* msg, const Thread* const thread) {
402 if (!TraceThreadEvents) return;
403 ResourceMark rm;
404 ThreadCritical tc;
405 const char *name = "non-Java thread";
406 int prio = -1;
407 if (thread->is_Java_thread()
408 && !thread->is_Compiler_thread()) {
409 // The Threads_lock must be held to get information about
410 // this thread but may not be in some situations when
411 // tracing thread events.
412 bool release_Threads_lock = false;
413 if (!Threads_lock->owned_by_self()) {
414 Threads_lock->lock();
415 release_Threads_lock = true;
416 }
417 JavaThread* jt = (JavaThread *)thread;
418 name = (char *)jt->get_thread_name();
419 oop thread_oop = jt->threadObj();
420 if (thread_oop != NULL) {
421 prio = java_lang_Thread::priority(thread_oop);
422 }
423 if (release_Threads_lock) {
424 Threads_lock->unlock();
425 }
426 }
427 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
428 }
429 #endif
430
431
432 ThreadPriority Thread::get_priority(const Thread* const thread) {
433 trace("get priority", thread);
434 ThreadPriority priority;
435 // Can return an error!
436 (void)os::get_priority(thread, priority);
437 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
438 return priority;
439 }
440
441 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
442 trace("set priority", thread);
443 debug_only(check_for_dangling_thread_pointer(thread);)
444 // Can return an error!
445 (void)os::set_priority(thread, priority);
446 }
447
448
449 void Thread::start(Thread* thread) {
450 trace("start", thread);
451 // Start is different from resume in that its safety is guaranteed by context or
452 // being called from a Java method synchronized on the Thread object.
453 if (!DisableStartThread) {
454 if (thread->is_Java_thread()) {
455 // Initialize the thread state to RUNNABLE before starting this thread.
456 // Can not set it after the thread started because we do not know the
457 // exact thread state at that time. It could be in MONITOR_WAIT or
458 // in SLEEPING or some other state.
459 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
460 java_lang_Thread::RUNNABLE);
461 }
462 os::start_thread(thread);
463 }
464 }
465
466 // Enqueue a VM_Operation to do the job for us - sometime later
467 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
468 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
469 VMThread::execute(vm_stop);
470 }
471
472
473 //
474 // Check if an external suspend request has completed (or has been
475 // cancelled). Returns true if the thread is externally suspended and
476 // false otherwise.
477 //
478 // The bits parameter returns information about the code path through
479 // the routine. Useful for debugging:
480 //
481 // set in is_ext_suspend_completed():
482 // 0x00000001 - routine was entered
483 // 0x00000010 - routine return false at end
484 // 0x00000100 - thread exited (return false)
485 // 0x00000200 - suspend request cancelled (return false)
486 // 0x00000400 - thread suspended (return true)
487 // 0x00001000 - thread is in a suspend equivalent state (return true)
488 // 0x00002000 - thread is native and walkable (return true)
489 // 0x00004000 - thread is native_trans and walkable (needed retry)
490 //
491 // set in wait_for_ext_suspend_completion():
492 // 0x00010000 - routine was entered
493 // 0x00020000 - suspend request cancelled before loop (return false)
494 // 0x00040000 - thread suspended before loop (return true)
495 // 0x00080000 - suspend request cancelled in loop (return false)
496 // 0x00100000 - thread suspended in loop (return true)
497 // 0x00200000 - suspend not completed during retry loop (return false)
498 //
499
500 // Helper class for tracing suspend wait debug bits.
501 //
502 // 0x00000100 indicates that the target thread exited before it could
503 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
504 // 0x00080000 each indicate a cancelled suspend request so they don't
505 // count as wait failures either.
506 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
507
508 class TraceSuspendDebugBits : public StackObj {
509 private:
510 JavaThread * jt;
511 bool is_wait;
512 bool called_by_wait; // meaningful when !is_wait
513 uint32_t * bits;
514
515 public:
516 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
517 uint32_t *_bits) {
518 jt = _jt;
519 is_wait = _is_wait;
520 called_by_wait = _called_by_wait;
521 bits = _bits;
522 }
523
524 ~TraceSuspendDebugBits() {
525 if (!is_wait) {
526 #if 1
527 // By default, don't trace bits for is_ext_suspend_completed() calls.
528 // That trace is very chatty.
529 return;
530 #else
531 if (!called_by_wait) {
532 // If tracing for is_ext_suspend_completed() is enabled, then only
533 // trace calls to it from wait_for_ext_suspend_completion()
534 return;
535 }
536 #endif
537 }
538
539 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
540 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
541 MutexLocker ml(Threads_lock); // needed for get_thread_name()
542 ResourceMark rm;
543
544 tty->print_cr(
545 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
546 jt->get_thread_name(), *bits);
547
548 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
549 }
550 }
551 }
552 };
553 #undef DEBUG_FALSE_BITS
554
555
556 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
557 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
558
559 bool did_trans_retry = false; // only do thread_in_native_trans retry once
560 bool do_trans_retry; // flag to force the retry
561
562 *bits |= 0x00000001;
563
564 do {
565 do_trans_retry = false;
566
567 if (is_exiting()) {
568 // Thread is in the process of exiting. This is always checked
569 // first to reduce the risk of dereferencing a freed JavaThread.
570 *bits |= 0x00000100;
571 return false;
572 }
573
574 if (!is_external_suspend()) {
575 // Suspend request is cancelled. This is always checked before
576 // is_ext_suspended() to reduce the risk of a rogue resume
577 // confusing the thread that made the suspend request.
578 *bits |= 0x00000200;
579 return false;
580 }
581
582 if (is_ext_suspended()) {
583 // thread is suspended
584 *bits |= 0x00000400;
585 return true;
586 }
587
588 // Now that we no longer do hard suspends of threads running
589 // native code, the target thread can be changing thread state
590 // while we are in this routine:
591 //
592 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
593 //
594 // We save a copy of the thread state as observed at this moment
595 // and make our decision about suspend completeness based on the
596 // copy. This closes the race where the thread state is seen as
597 // _thread_in_native_trans in the if-thread_blocked check, but is
598 // seen as _thread_blocked in if-thread_in_native_trans check.
599 JavaThreadState save_state = thread_state();
600
601 if (save_state == _thread_blocked && is_suspend_equivalent()) {
602 // If the thread's state is _thread_blocked and this blocking
603 // condition is known to be equivalent to a suspend, then we can
604 // consider the thread to be externally suspended. This means that
605 // the code that sets _thread_blocked has been modified to do
606 // self-suspension if the blocking condition releases. We also
607 // used to check for CONDVAR_WAIT here, but that is now covered by
608 // the _thread_blocked with self-suspension check.
609 //
610 // Return true since we wouldn't be here unless there was still an
611 // external suspend request.
612 *bits |= 0x00001000;
613 return true;
614 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
615 // Threads running native code will self-suspend on native==>VM/Java
616 // transitions. If its stack is walkable (should always be the case
617 // unless this function is called before the actual java_suspend()
618 // call), then the wait is done.
619 *bits |= 0x00002000;
620 return true;
621 } else if (!called_by_wait && !did_trans_retry &&
622 save_state == _thread_in_native_trans &&
623 frame_anchor()->walkable()) {
624 // The thread is transitioning from thread_in_native to another
625 // thread state. check_safepoint_and_suspend_for_native_trans()
626 // will force the thread to self-suspend. If it hasn't gotten
627 // there yet we may have caught the thread in-between the native
628 // code check above and the self-suspend. Lucky us. If we were
629 // called by wait_for_ext_suspend_completion(), then it
630 // will be doing the retries so we don't have to.
631 //
632 // Since we use the saved thread state in the if-statement above,
633 // there is a chance that the thread has already transitioned to
634 // _thread_blocked by the time we get here. In that case, we will
635 // make a single unnecessary pass through the logic below. This
636 // doesn't hurt anything since we still do the trans retry.
637
638 *bits |= 0x00004000;
639
640 // Once the thread leaves thread_in_native_trans for another
641 // thread state, we break out of this retry loop. We shouldn't
642 // need this flag to prevent us from getting back here, but
643 // sometimes paranoia is good.
644 did_trans_retry = true;
645
646 // We wait for the thread to transition to a more usable state.
647 for (int i = 1; i <= SuspendRetryCount; i++) {
648 // We used to do an "os::yield_all(i)" call here with the intention
649 // that yielding would increase on each retry. However, the parameter
650 // is ignored on Linux which means the yield didn't scale up. Waiting
651 // on the SR_lock below provides a much more predictable scale up for
652 // the delay. It also provides a simple/direct point to check for any
653 // safepoint requests from the VMThread
654
655 // temporarily drops SR_lock while doing wait with safepoint check
656 // (if we're a JavaThread - the WatcherThread can also call this)
657 // and increase delay with each retry
658 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
659
660 // check the actual thread state instead of what we saved above
661 if (thread_state() != _thread_in_native_trans) {
662 // the thread has transitioned to another thread state so
663 // try all the checks (except this one) one more time.
664 do_trans_retry = true;
665 break;
666 }
667 } // end retry loop
668
669
670 }
671 } while (do_trans_retry);
672
673 *bits |= 0x00000010;
674 return false;
675 }
676
677 //
678 // Wait for an external suspend request to complete (or be cancelled).
679 // Returns true if the thread is externally suspended and false otherwise.
680 //
681 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
682 uint32_t *bits) {
683 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
684 false /* !called_by_wait */, bits);
685
686 // local flag copies to minimize SR_lock hold time
687 bool is_suspended;
688 bool pending;
689 uint32_t reset_bits;
690
691 // set a marker so is_ext_suspend_completed() knows we are the caller
692 *bits |= 0x00010000;
693
694 // We use reset_bits to reinitialize the bits value at the top of
695 // each retry loop. This allows the caller to make use of any
696 // unused bits for their own marking purposes.
697 reset_bits = *bits;
698
699 {
700 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
701 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
702 delay, bits);
703 pending = is_external_suspend();
704 }
705 // must release SR_lock to allow suspension to complete
706
707 if (!pending) {
708 // A cancelled suspend request is the only false return from
709 // is_ext_suspend_completed() that keeps us from entering the
710 // retry loop.
711 *bits |= 0x00020000;
712 return false;
713 }
714
715 if (is_suspended) {
716 *bits |= 0x00040000;
717 return true;
718 }
719
720 for (int i = 1; i <= retries; i++) {
721 *bits = reset_bits; // reinit to only track last retry
722
723 // We used to do an "os::yield_all(i)" call here with the intention
724 // that yielding would increase on each retry. However, the parameter
725 // is ignored on Linux which means the yield didn't scale up. Waiting
726 // on the SR_lock below provides a much more predictable scale up for
727 // the delay. It also provides a simple/direct point to check for any
728 // safepoint requests from the VMThread
729
730 {
731 MutexLocker ml(SR_lock());
732 // wait with safepoint check (if we're a JavaThread - the WatcherThread
733 // can also call this) and increase delay with each retry
734 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
735
736 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
737 delay, bits);
738
739 // It is possible for the external suspend request to be cancelled
740 // (by a resume) before the actual suspend operation is completed.
741 // Refresh our local copy to see if we still need to wait.
742 pending = is_external_suspend();
743 }
744
745 if (!pending) {
746 // A cancelled suspend request is the only false return from
747 // is_ext_suspend_completed() that keeps us from staying in the
748 // retry loop.
749 *bits |= 0x00080000;
750 return false;
751 }
752
753 if (is_suspended) {
754 *bits |= 0x00100000;
755 return true;
756 }
757 } // end retry loop
758
759 // thread did not suspend after all our retries
760 *bits |= 0x00200000;
761 return false;
762 }
763
764 #ifndef PRODUCT
765 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
766
767 // This should not need to be atomic as the only way for simultaneous
768 // updates is via interrupts. Even then this should be rare or non-existant
769 // and we don't care that much anyway.
770
771 int index = _jmp_ring_index;
772 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
773 _jmp_ring[index]._target = (intptr_t) target;
774 _jmp_ring[index]._instruction = (intptr_t) instr;
775 _jmp_ring[index]._file = file;
776 _jmp_ring[index]._line = line;
777 }
778 #endif /* PRODUCT */
779
780 // Called by flat profiler
781 // Callers have already called wait_for_ext_suspend_completion
782 // The assertion for that is currently too complex to put here:
783 bool JavaThread::profile_last_Java_frame(frame* _fr) {
784 bool gotframe = false;
785 // self suspension saves needed state.
786 if (has_last_Java_frame() && _anchor.walkable()) {
787 *_fr = pd_last_frame();
788 gotframe = true;
789 }
790 return gotframe;
791 }
792
793 void Thread::interrupt(Thread* thread) {
794 trace("interrupt", thread);
795 debug_only(check_for_dangling_thread_pointer(thread);)
796 os::interrupt(thread);
797 }
798
799 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
800 trace("is_interrupted", thread);
801 debug_only(check_for_dangling_thread_pointer(thread);)
802 // Note: If clear_interrupted==false, this simply fetches and
803 // returns the value of the field osthread()->interrupted().
804 return os::is_interrupted(thread, clear_interrupted);
805 }
806
807
808 // GC Support
809 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
810 jint thread_parity = _oops_do_parity;
811 if (thread_parity != strong_roots_parity) {
812 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
813 if (res == thread_parity) {
814 return true;
815 } else {
816 guarantee(res == strong_roots_parity, "Or else what?");
817 assert(SharedHeap::heap()->workers()->active_workers() > 0,
818 "Should only fail when parallel.");
819 return false;
820 }
821 }
822 assert(SharedHeap::heap()->workers()->active_workers() > 0,
823 "Should only fail when parallel.");
824 return false;
825 }
826
827 void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
828 active_handles()->oops_do(f);
829 // Do oop for ThreadShadow
830 f->do_oop((oop*)&_pending_exception);
831 handle_area()->oops_do(f);
832 }
833
834 void Thread::nmethods_do(CodeBlobClosure* cf) {
835 // no nmethods in a generic thread...
836 }
837
838 void Thread::metadata_do(void f(Metadata*)) {
839 if (metadata_handles() != NULL) {
840 for (int i = 0; i< metadata_handles()->length(); i++) {
841 f(metadata_handles()->at(i));
842 }
843 }
844 }
845
846 void Thread::print_on(outputStream* st) const {
847 // get_priority assumes osthread initialized
848 if (osthread() != NULL) {
849 int os_prio;
850 if (os::get_native_priority(this, &os_prio) == OS_OK) {
851 st->print("os_prio=%d ", os_prio);
852 }
853 st->print("tid=" INTPTR_FORMAT " ", this);
854 osthread()->print_on(st);
855 }
856 debug_only(if (WizardMode) print_owned_locks_on(st);)
857 }
858
859 // Thread::print_on_error() is called by fatal error handler. Don't use
860 // any lock or allocate memory.
861 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
862 if (is_VM_thread()) st->print("VMThread");
863 else if (is_Compiler_thread()) st->print("CompilerThread");
864 else if (is_Java_thread()) st->print("JavaThread");
865 else if (is_GC_task_thread()) st->print("GCTaskThread");
866 else if (is_Watcher_thread()) st->print("WatcherThread");
867 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
868 else st->print("Thread");
869
870 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
871 _stack_base - _stack_size, _stack_base);
872
873 if (osthread()) {
874 st->print(" [id=%d]", osthread()->thread_id());
875 }
876 }
877
878 #ifdef ASSERT
879 void Thread::print_owned_locks_on(outputStream* st) const {
880 Monitor *cur = _owned_locks;
881 if (cur == NULL) {
882 st->print(" (no locks) ");
883 } else {
884 st->print_cr(" Locks owned:");
885 while(cur) {
886 cur->print_on(st);
887 cur = cur->next();
888 }
889 }
890 }
891
892 static int ref_use_count = 0;
893
894 bool Thread::owns_locks_but_compiled_lock() const {
895 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
896 if (cur != Compile_lock) return true;
897 }
898 return false;
899 }
900
901
902 #endif
903
904 #ifndef PRODUCT
905
906 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
907 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
908 // no threads which allow_vm_block's are held
909 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
910 // Check if current thread is allowed to block at a safepoint
911 if (!(_allow_safepoint_count == 0))
912 fatal("Possible safepoint reached by thread that does not allow it");
913 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
914 fatal("LEAF method calling lock?");
915 }
916
917 #ifdef ASSERT
918 if (potential_vm_operation && is_Java_thread()
919 && !Universe::is_bootstrapping()) {
920 // Make sure we do not hold any locks that the VM thread also uses.
921 // This could potentially lead to deadlocks
922 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
923 // Threads_lock is special, since the safepoint synchronization will not start before this is
924 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
925 // since it is used to transfer control between JavaThreads and the VMThread
926 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
927 if ( (cur->allow_vm_block() &&
928 cur != Threads_lock &&
929 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
930 cur != VMOperationRequest_lock &&
931 cur != VMOperationQueue_lock) ||
932 cur->rank() == Mutex::special) {
933 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
934 }
935 }
936 }
937
938 if (GCALotAtAllSafepoints) {
939 // We could enter a safepoint here and thus have a gc
940 InterfaceSupport::check_gc_alot();
941 }
942 #endif
943 }
944 #endif
945
946 bool Thread::is_in_stack(address adr) const {
947 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
948 address end = os::current_stack_pointer();
949 // Allow non Java threads to call this without stack_base
950 if (_stack_base == NULL) return true;
951 if (stack_base() >= adr && adr >= end) return true;
952
953 return false;
954 }
955
956
957 bool Thread::is_in_usable_stack(address adr) const {
958 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
959 size_t usable_stack_size = _stack_size - stack_guard_size;
960
961 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
962 }
963
964
965 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
966 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
967 // used for compilation in the future. If that change is made, the need for these methods
968 // should be revisited, and they should be removed if possible.
969
970 bool Thread::is_lock_owned(address adr) const {
971 return on_local_stack(adr);
972 }
973
974 bool Thread::set_as_starting_thread() {
975 // NOTE: this must be called inside the main thread.
976 return os::create_main_thread((JavaThread*)this);
977 }
978
979 static void initialize_class(Symbol* class_name, TRAPS) {
980 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
981 InstanceKlass::cast(klass)->initialize(CHECK);
982 }
983
984
985 // Creates the initial ThreadGroup
986 static Handle create_initial_thread_group(TRAPS) {
987 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
988 instanceKlassHandle klass (THREAD, k);
989
990 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
991 {
992 JavaValue result(T_VOID);
993 JavaCalls::call_special(&result,
994 system_instance,
995 klass,
996 vmSymbols::object_initializer_name(),
997 vmSymbols::void_method_signature(),
998 CHECK_NH);
999 }
1000 Universe::set_system_thread_group(system_instance());
1001
1002 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1003 {
1004 JavaValue result(T_VOID);
1005 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1006 JavaCalls::call_special(&result,
1007 main_instance,
1008 klass,
1009 vmSymbols::object_initializer_name(),
1010 vmSymbols::threadgroup_string_void_signature(),
1011 system_instance,
1012 string,
1013 CHECK_NH);
1014 }
1015 return main_instance;
1016 }
1017
1018 // Creates the initial Thread
1019 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1020 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1021 instanceKlassHandle klass (THREAD, k);
1022 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1023
1024 java_lang_Thread::set_thread(thread_oop(), thread);
1025 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1026 thread->set_threadObj(thread_oop());
1027
1028 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1029
1030 JavaValue result(T_VOID);
1031 JavaCalls::call_special(&result, thread_oop,
1032 klass,
1033 vmSymbols::object_initializer_name(),
1034 vmSymbols::threadgroup_string_void_signature(),
1035 thread_group,
1036 string,
1037 CHECK_NULL);
1038 return thread_oop();
1039 }
1040
1041 static void call_initializeSystemClass(TRAPS) {
1042 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1043 instanceKlassHandle klass (THREAD, k);
1044
1045 JavaValue result(T_VOID);
1046 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1047 vmSymbols::void_method_signature(), CHECK);
1048 }
1049
1050 char java_runtime_name[128] = "";
1051 char java_runtime_version[128] = "";
1052
1053 // extract the JRE name from sun.misc.Version.java_runtime_name
1054 static const char* get_java_runtime_name(TRAPS) {
1055 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1056 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1057 fieldDescriptor fd;
1058 bool found = k != NULL &&
1059 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1060 vmSymbols::string_signature(), &fd);
1061 if (found) {
1062 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1063 if (name_oop == NULL)
1064 return NULL;
1065 const char* name = java_lang_String::as_utf8_string(name_oop,
1066 java_runtime_name,
1067 sizeof(java_runtime_name));
1068 return name;
1069 } else {
1070 return NULL;
1071 }
1072 }
1073
1074 // extract the JRE version from sun.misc.Version.java_runtime_version
1075 static const char* get_java_runtime_version(TRAPS) {
1076 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1077 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1078 fieldDescriptor fd;
1079 bool found = k != NULL &&
1080 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1081 vmSymbols::string_signature(), &fd);
1082 if (found) {
1083 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1084 if (name_oop == NULL)
1085 return NULL;
1086 const char* name = java_lang_String::as_utf8_string(name_oop,
1087 java_runtime_version,
1088 sizeof(java_runtime_version));
1089 return name;
1090 } else {
1091 return NULL;
1092 }
1093 }
1094
1095 // General purpose hook into Java code, run once when the VM is initialized.
1096 // The Java library method itself may be changed independently from the VM.
1097 static void call_postVMInitHook(TRAPS) {
1098 Klass* k = SystemDictionary::PostVMInitHook_klass();
1099 instanceKlassHandle klass (THREAD, k);
1100 if (klass.not_null()) {
1101 JavaValue result(T_VOID);
1102 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1103 vmSymbols::void_method_signature(),
1104 CHECK);
1105 }
1106 }
1107
1108 static void reset_vm_info_property(TRAPS) {
1109 // the vm info string
1110 ResourceMark rm(THREAD);
1111 const char *vm_info = VM_Version::vm_info_string();
1112
1113 // java.lang.System class
1114 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1115 instanceKlassHandle klass (THREAD, k);
1116
1117 // setProperty arguments
1118 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1119 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1120
1121 // return value
1122 JavaValue r(T_OBJECT);
1123
1124 // public static String setProperty(String key, String value);
1125 JavaCalls::call_static(&r,
1126 klass,
1127 vmSymbols::setProperty_name(),
1128 vmSymbols::string_string_string_signature(),
1129 key_str,
1130 value_str,
1131 CHECK);
1132 }
1133
1134
1135 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1136 assert(thread_group.not_null(), "thread group should be specified");
1137 assert(threadObj() == NULL, "should only create Java thread object once");
1138
1139 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1140 instanceKlassHandle klass (THREAD, k);
1141 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1142
1143 java_lang_Thread::set_thread(thread_oop(), this);
1144 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1145 set_threadObj(thread_oop());
1146
1147 JavaValue result(T_VOID);
1148 if (thread_name != NULL) {
1149 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1150 // Thread gets assigned specified name and null target
1151 JavaCalls::call_special(&result,
1152 thread_oop,
1153 klass,
1154 vmSymbols::object_initializer_name(),
1155 vmSymbols::threadgroup_string_void_signature(),
1156 thread_group, // Argument 1
1157 name, // Argument 2
1158 THREAD);
1159 } else {
1160 // Thread gets assigned name "Thread-nnn" and null target
1161 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1162 JavaCalls::call_special(&result,
1163 thread_oop,
1164 klass,
1165 vmSymbols::object_initializer_name(),
1166 vmSymbols::threadgroup_runnable_void_signature(),
1167 thread_group, // Argument 1
1168 Handle(), // Argument 2
1169 THREAD);
1170 }
1171
1172
1173 if (daemon) {
1174 java_lang_Thread::set_daemon(thread_oop());
1175 }
1176
1177 if (HAS_PENDING_EXCEPTION) {
1178 return;
1179 }
1180
1181 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1182 Handle threadObj(this, this->threadObj());
1183
1184 JavaCalls::call_special(&result,
1185 thread_group,
1186 group,
1187 vmSymbols::add_method_name(),
1188 vmSymbols::thread_void_signature(),
1189 threadObj, // Arg 1
1190 THREAD);
1191
1192
1193 }
1194
1195 // NamedThread -- non-JavaThread subclasses with multiple
1196 // uniquely named instances should derive from this.
1197 NamedThread::NamedThread() : Thread() {
1198 _name = NULL;
1199 _processed_thread = NULL;
1200 }
1201
1202 NamedThread::~NamedThread() {
1203 if (_name != NULL) {
1204 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1205 _name = NULL;
1206 }
1207 }
1208
1209 void NamedThread::set_name(const char* format, ...) {
1210 guarantee(_name == NULL, "Only get to set name once.");
1211 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1212 guarantee(_name != NULL, "alloc failure");
1213 va_list ap;
1214 va_start(ap, format);
1215 jio_vsnprintf(_name, max_name_len, format, ap);
1216 va_end(ap);
1217 }
1218
1219 // ======= WatcherThread ========
1220
1221 // The watcher thread exists to simulate timer interrupts. It should
1222 // be replaced by an abstraction over whatever native support for
1223 // timer interrupts exists on the platform.
1224
1225 WatcherThread* WatcherThread::_watcher_thread = NULL;
1226 bool WatcherThread::_startable = false;
1227 volatile bool WatcherThread::_should_terminate = false;
1228
1229 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1230 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1231 if (os::create_thread(this, os::watcher_thread)) {
1232 _watcher_thread = this;
1233
1234 // Set the watcher thread to the highest OS priority which should not be
1235 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1236 // is created. The only normal thread using this priority is the reference
1237 // handler thread, which runs for very short intervals only.
1238 // If the VMThread's priority is not lower than the WatcherThread profiling
1239 // will be inaccurate.
1240 os::set_priority(this, MaxPriority);
1241 if (!DisableStartThread) {
1242 os::start_thread(this);
1243 }
1244 }
1245 }
1246
1247 int WatcherThread::sleep() const {
1248 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1249
1250 // remaining will be zero if there are no tasks,
1251 // causing the WatcherThread to sleep until a task is
1252 // enrolled
1253 int remaining = PeriodicTask::time_to_wait();
1254 int time_slept = 0;
1255
1256 // we expect this to timeout - we only ever get unparked when
1257 // we should terminate or when a new task has been enrolled
1258 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1259
1260 jlong time_before_loop = os::javaTimeNanos();
1261
1262 for (;;) {
1263 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1264 jlong now = os::javaTimeNanos();
1265
1266 if (remaining == 0) {
1267 // if we didn't have any tasks we could have waited for a long time
1268 // consider the time_slept zero and reset time_before_loop
1269 time_slept = 0;
1270 time_before_loop = now;
1271 } else {
1272 // need to recalulate since we might have new tasks in _tasks
1273 time_slept = (int) ((now - time_before_loop) / 1000000);
1274 }
1275
1276 // Change to task list or spurious wakeup of some kind
1277 if (timedout || _should_terminate) {
1278 break;
1279 }
1280
1281 remaining = PeriodicTask::time_to_wait();
1282 if (remaining == 0) {
1283 // Last task was just disenrolled so loop around and wait until
1284 // another task gets enrolled
1285 continue;
1286 }
1287
1288 remaining -= time_slept;
1289 if (remaining <= 0)
1290 break;
1291 }
1292
1293 return time_slept;
1294 }
1295
1296 void WatcherThread::run() {
1297 assert(this == watcher_thread(), "just checking");
1298
1299 this->record_stack_base_and_size();
1300 this->initialize_thread_local_storage();
1301 this->set_active_handles(JNIHandleBlock::allocate_block());
1302 while(!_should_terminate) {
1303 assert(watcher_thread() == Thread::current(), "thread consistency check");
1304 assert(watcher_thread() == this, "thread consistency check");
1305
1306 // Calculate how long it'll be until the next PeriodicTask work
1307 // should be done, and sleep that amount of time.
1308 int time_waited = sleep();
1309
1310 if (is_error_reported()) {
1311 // A fatal error has happened, the error handler(VMError::report_and_die)
1312 // should abort JVM after creating an error log file. However in some
1313 // rare cases, the error handler itself might deadlock. Here we try to
1314 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1315 //
1316 // This code is in WatcherThread because WatcherThread wakes up
1317 // periodically so the fatal error handler doesn't need to do anything;
1318 // also because the WatcherThread is less likely to crash than other
1319 // threads.
1320
1321 for (;;) {
1322 if (!ShowMessageBoxOnError
1323 && (OnError == NULL || OnError[0] == '\0')
1324 && Arguments::abort_hook() == NULL) {
1325 os::sleep(this, 2 * 60 * 1000, false);
1326 fdStream err(defaultStream::output_fd());
1327 err.print_raw_cr("# [ timer expired, abort... ]");
1328 // skip atexit/vm_exit/vm_abort hooks
1329 os::die();
1330 }
1331
1332 // Wake up 5 seconds later, the fatal handler may reset OnError or
1333 // ShowMessageBoxOnError when it is ready to abort.
1334 os::sleep(this, 5 * 1000, false);
1335 }
1336 }
1337
1338 PeriodicTask::real_time_tick(time_waited);
1339 }
1340
1341 // Signal that it is terminated
1342 {
1343 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1344 _watcher_thread = NULL;
1345 Terminator_lock->notify();
1346 }
1347
1348 // Thread destructor usually does this..
1349 ThreadLocalStorage::set_thread(NULL);
1350 }
1351
1352 void WatcherThread::start() {
1353 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1354
1355 if (watcher_thread() == NULL && _startable) {
1356 _should_terminate = false;
1357 // Create the single instance of WatcherThread
1358 new WatcherThread();
1359 }
1360 }
1361
1362 void WatcherThread::make_startable() {
1363 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1364 _startable = true;
1365 }
1366
1367 void WatcherThread::stop() {
1368 {
1369 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1370 _should_terminate = true;
1371 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1372
1373 WatcherThread* watcher = watcher_thread();
1374 if (watcher != NULL)
1375 watcher->unpark();
1376 }
1377
1378 // it is ok to take late safepoints here, if needed
1379 MutexLocker mu(Terminator_lock);
1380
1381 while(watcher_thread() != NULL) {
1382 // This wait should make safepoint checks, wait without a timeout,
1383 // and wait as a suspend-equivalent condition.
1384 //
1385 // Note: If the FlatProfiler is running, then this thread is waiting
1386 // for the WatcherThread to terminate and the WatcherThread, via the
1387 // FlatProfiler task, is waiting for the external suspend request on
1388 // this thread to complete. wait_for_ext_suspend_completion() will
1389 // eventually timeout, but that takes time. Making this wait a
1390 // suspend-equivalent condition solves that timeout problem.
1391 //
1392 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1393 Mutex::_as_suspend_equivalent_flag);
1394 }
1395 }
1396
1397 void WatcherThread::unpark() {
1398 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1399 PeriodicTask_lock->notify();
1400 }
1401
1402 void WatcherThread::print_on(outputStream* st) const {
1403 st->print("\"%s\" ", name());
1404 Thread::print_on(st);
1405 st->cr();
1406 }
1407
1408 // ======= JavaThread ========
1409
1410 // A JavaThread is a normal Java thread
1411
1412 void JavaThread::initialize() {
1413 // Initialize fields
1414
1415 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1416 set_claimed_par_id(-1);
1417
1418 set_saved_exception_pc(NULL);
1419 set_threadObj(NULL);
1420 _anchor.clear();
1421 set_entry_point(NULL);
1422 set_jni_functions(jni_functions());
1423 set_callee_target(NULL);
1424 set_vm_result(NULL);
1425 set_vm_result_2(NULL);
1426 set_vframe_array_head(NULL);
1427 set_vframe_array_last(NULL);
1428 set_deferred_locals(NULL);
1429 set_deopt_mark(NULL);
1430 set_deopt_nmethod(NULL);
1431 clear_must_deopt_id();
1432 set_monitor_chunks(NULL);
1433 set_next(NULL);
1434 set_thread_state(_thread_new);
1435 #if INCLUDE_NMT
1436 set_recorder(NULL);
1437 #endif
1438 _terminated = _not_terminated;
1439 _privileged_stack_top = NULL;
1440 _array_for_gc = NULL;
1441 _suspend_equivalent = false;
1442 _in_deopt_handler = 0;
1443 _doing_unsafe_access = false;
1444 _stack_guard_state = stack_guard_unused;
1445 _exception_oop = NULL;
1446 _exception_pc = 0;
1447 _exception_handler_pc = 0;
1448 _is_method_handle_return = 0;
1449 _jvmti_thread_state= NULL;
1450 _should_post_on_exceptions_flag = JNI_FALSE;
1451 _jvmti_get_loaded_classes_closure = NULL;
1452 _interp_only_mode = 0;
1453 _special_runtime_exit_condition = _no_async_condition;
1454 _pending_async_exception = NULL;
1455 _is_compiling = false;
1456 _thread_stat = NULL;
1457 _thread_stat = new ThreadStatistics();
1458 _blocked_on_compilation = false;
1459 _jni_active_critical = 0;
1460 _do_not_unlock_if_synchronized = false;
1461 _cached_monitor_info = NULL;
1462 _parker = Parker::Allocate(this) ;
1463
1464 #ifndef PRODUCT
1465 _jmp_ring_index = 0;
1466 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1467 record_jump(NULL, NULL, NULL, 0);
1468 }
1469 #endif /* PRODUCT */
1470
1471 set_thread_profiler(NULL);
1472 if (FlatProfiler::is_active()) {
1473 // This is where we would decide to either give each thread it's own profiler
1474 // or use one global one from FlatProfiler,
1475 // or up to some count of the number of profiled threads, etc.
1476 ThreadProfiler* pp = new ThreadProfiler();
1477 pp->engage();
1478 set_thread_profiler(pp);
1479 }
1480
1481 // Setup safepoint state info for this thread
1482 ThreadSafepointState::create(this);
1483
1484 debug_only(_java_call_counter = 0);
1485
1486 // JVMTI PopFrame support
1487 _popframe_condition = popframe_inactive;
1488 _popframe_preserved_args = NULL;
1489 _popframe_preserved_args_size = 0;
1490
1491 pd_initialize();
1492 }
1493
1494 #if INCLUDE_ALL_GCS
1495 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1496 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1497 #endif // INCLUDE_ALL_GCS
1498
1499 JavaThread::JavaThread(bool is_attaching_via_jni) :
1500 Thread()
1501 #if INCLUDE_ALL_GCS
1502 , _satb_mark_queue(&_satb_mark_queue_set),
1503 _dirty_card_queue(&_dirty_card_queue_set)
1504 #endif // INCLUDE_ALL_GCS
1505 {
1506 initialize();
1507 if (is_attaching_via_jni) {
1508 _jni_attach_state = _attaching_via_jni;
1509 } else {
1510 _jni_attach_state = _not_attaching_via_jni;
1511 }
1512 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1513 _safepoint_visible = false;
1514 }
1515
1516 bool JavaThread::reguard_stack(address cur_sp) {
1517 if (_stack_guard_state != stack_guard_yellow_disabled) {
1518 return true; // Stack already guarded or guard pages not needed.
1519 }
1520
1521 if (register_stack_overflow()) {
1522 // For those architectures which have separate register and
1523 // memory stacks, we must check the register stack to see if
1524 // it has overflowed.
1525 return false;
1526 }
1527
1528 // Java code never executes within the yellow zone: the latter is only
1529 // there to provoke an exception during stack banging. If java code
1530 // is executing there, either StackShadowPages should be larger, or
1531 // some exception code in c1, c2 or the interpreter isn't unwinding
1532 // when it should.
1533 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1534
1535 enable_stack_yellow_zone();
1536 return true;
1537 }
1538
1539 bool JavaThread::reguard_stack(void) {
1540 return reguard_stack(os::current_stack_pointer());
1541 }
1542
1543
1544 void JavaThread::block_if_vm_exited() {
1545 if (_terminated == _vm_exited) {
1546 // _vm_exited is set at safepoint, and Threads_lock is never released
1547 // we will block here forever
1548 Threads_lock->lock_without_safepoint_check();
1549 ShouldNotReachHere();
1550 }
1551 }
1552
1553
1554 // Remove this ifdef when C1 is ported to the compiler interface.
1555 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1556
1557 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1558 Thread()
1559 #if INCLUDE_ALL_GCS
1560 , _satb_mark_queue(&_satb_mark_queue_set),
1561 _dirty_card_queue(&_dirty_card_queue_set)
1562 #endif // INCLUDE_ALL_GCS
1563 {
1564 if (TraceThreadEvents) {
1565 tty->print_cr("creating thread %p", this);
1566 }
1567 initialize();
1568 _jni_attach_state = _not_attaching_via_jni;
1569 set_entry_point(entry_point);
1570 // Create the native thread itself.
1571 // %note runtime_23
1572 os::ThreadType thr_type = os::java_thread;
1573 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1574 os::java_thread;
1575 os::create_thread(this, thr_type, stack_sz);
1576 _safepoint_visible = false;
1577 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1578 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1579 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1580 // the exception consists of creating the exception object & initializing it, initialization
1581 // will leave the VM via a JavaCall and then all locks must be unlocked).
1582 //
1583 // The thread is still suspended when we reach here. Thread must be explicit started
1584 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1585 // by calling Threads:add. The reason why this is not done here, is because the thread
1586 // object must be fully initialized (take a look at JVM_Start)
1587 }
1588
1589 JavaThread::~JavaThread() {
1590 if (TraceThreadEvents) {
1591 tty->print_cr("terminate thread %p", this);
1592 }
1593
1594 // By now, this thread should already be invisible to safepoint,
1595 // and its per-thread recorder also collected.
1596 assert(!is_safepoint_visible(), "wrong state");
1597 #if INCLUDE_NMT
1598 assert(get_recorder() == NULL, "Already collected");
1599 #endif // INCLUDE_NMT
1600
1601 // JSR166 -- return the parker to the free list
1602 Parker::Release(_parker);
1603 _parker = NULL ;
1604
1605 // Free any remaining previous UnrollBlock
1606 vframeArray* old_array = vframe_array_last();
1607
1608 if (old_array != NULL) {
1609 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1610 old_array->set_unroll_block(NULL);
1611 delete old_info;
1612 delete old_array;
1613 }
1614
1615 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1616 if (deferred != NULL) {
1617 // This can only happen if thread is destroyed before deoptimization occurs.
1618 assert(deferred->length() != 0, "empty array!");
1619 do {
1620 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1621 deferred->remove_at(0);
1622 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1623 delete dlv;
1624 } while (deferred->length() != 0);
1625 delete deferred;
1626 }
1627
1628 // All Java related clean up happens in exit
1629 ThreadSafepointState::destroy(this);
1630 if (_thread_profiler != NULL) delete _thread_profiler;
1631 if (_thread_stat != NULL) delete _thread_stat;
1632 }
1633
1634
1635 // The first routine called by a new Java thread
1636 void JavaThread::run() {
1637 // initialize thread-local alloc buffer related fields
1638 this->initialize_tlab();
1639
1640 // used to test validitity of stack trace backs
1641 this->record_base_of_stack_pointer();
1642
1643 // Record real stack base and size.
1644 this->record_stack_base_and_size();
1645
1646 // Initialize thread local storage; set before calling MutexLocker
1647 this->initialize_thread_local_storage();
1648
1649 this->create_stack_guard_pages();
1650
1651 this->cache_global_variables();
1652
1653 // Thread is now sufficient initialized to be handled by the safepoint code as being
1654 // in the VM. Change thread state from _thread_new to _thread_in_vm
1655 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1656
1657 assert(JavaThread::current() == this, "sanity check");
1658 assert(!Thread::current()->owns_locks(), "sanity check");
1659
1660 DTRACE_THREAD_PROBE(start, this);
1661
1662 // This operation might block. We call that after all safepoint checks for a new thread has
1663 // been completed.
1664 this->set_active_handles(JNIHandleBlock::allocate_block());
1665
1666 if (JvmtiExport::should_post_thread_life()) {
1667 JvmtiExport::post_thread_start(this);
1668 }
1669
1670 EventThreadStart event;
1671 if (event.should_commit()) {
1672 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1673 event.commit();
1674 }
1675
1676 // We call another function to do the rest so we are sure that the stack addresses used
1677 // from there will be lower than the stack base just computed
1678 thread_main_inner();
1679
1680 // Note, thread is no longer valid at this point!
1681 }
1682
1683
1684 void JavaThread::thread_main_inner() {
1685 assert(JavaThread::current() == this, "sanity check");
1686 assert(this->threadObj() != NULL, "just checking");
1687
1688 // Execute thread entry point unless this thread has a pending exception
1689 // or has been stopped before starting.
1690 // Note: Due to JVM_StopThread we can have pending exceptions already!
1691 if (!this->has_pending_exception() &&
1692 !java_lang_Thread::is_stillborn(this->threadObj())) {
1693 {
1694 ResourceMark rm(this);
1695 this->set_native_thread_name(this->get_thread_name());
1696 }
1697 HandleMark hm(this);
1698 this->entry_point()(this, this);
1699 }
1700
1701 DTRACE_THREAD_PROBE(stop, this);
1702
1703 this->exit(false);
1704 delete this;
1705 }
1706
1707
1708 static void ensure_join(JavaThread* thread) {
1709 // We do not need to grap the Threads_lock, since we are operating on ourself.
1710 Handle threadObj(thread, thread->threadObj());
1711 assert(threadObj.not_null(), "java thread object must exist");
1712 ObjectLocker lock(threadObj, thread);
1713 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1714 thread->clear_pending_exception();
1715 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1716 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1717 // Clear the native thread instance - this makes isAlive return false and allows the join()
1718 // to complete once we've done the notify_all below
1719 java_lang_Thread::set_thread(threadObj(), NULL);
1720 lock.notify_all(thread);
1721 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1722 thread->clear_pending_exception();
1723 }
1724
1725
1726 // For any new cleanup additions, please check to see if they need to be applied to
1727 // cleanup_failed_attach_current_thread as well.
1728 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1729 assert(this == JavaThread::current(), "thread consistency check");
1730
1731 HandleMark hm(this);
1732 Handle uncaught_exception(this, this->pending_exception());
1733 this->clear_pending_exception();
1734 Handle threadObj(this, this->threadObj());
1735 assert(threadObj.not_null(), "Java thread object should be created");
1736
1737 if (get_thread_profiler() != NULL) {
1738 get_thread_profiler()->disengage();
1739 ResourceMark rm;
1740 get_thread_profiler()->print(get_thread_name());
1741 }
1742
1743
1744 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1745 {
1746 EXCEPTION_MARK;
1747
1748 CLEAR_PENDING_EXCEPTION;
1749 }
1750 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1751 // has to be fixed by a runtime query method
1752 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1753 // JSR-166: change call from from ThreadGroup.uncaughtException to
1754 // java.lang.Thread.dispatchUncaughtException
1755 if (uncaught_exception.not_null()) {
1756 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1757 {
1758 EXCEPTION_MARK;
1759 // Check if the method Thread.dispatchUncaughtException() exists. If so
1760 // call it. Otherwise we have an older library without the JSR-166 changes,
1761 // so call ThreadGroup.uncaughtException()
1762 KlassHandle recvrKlass(THREAD, threadObj->klass());
1763 CallInfo callinfo;
1764 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1765 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1766 vmSymbols::dispatchUncaughtException_name(),
1767 vmSymbols::throwable_void_signature(),
1768 KlassHandle(), false, false, THREAD);
1769 CLEAR_PENDING_EXCEPTION;
1770 methodHandle method = callinfo.selected_method();
1771 if (method.not_null()) {
1772 JavaValue result(T_VOID);
1773 JavaCalls::call_virtual(&result,
1774 threadObj, thread_klass,
1775 vmSymbols::dispatchUncaughtException_name(),
1776 vmSymbols::throwable_void_signature(),
1777 uncaught_exception,
1778 THREAD);
1779 } else {
1780 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1781 JavaValue result(T_VOID);
1782 JavaCalls::call_virtual(&result,
1783 group, thread_group,
1784 vmSymbols::uncaughtException_name(),
1785 vmSymbols::thread_throwable_void_signature(),
1786 threadObj, // Arg 1
1787 uncaught_exception, // Arg 2
1788 THREAD);
1789 }
1790 if (HAS_PENDING_EXCEPTION) {
1791 ResourceMark rm(this);
1792 jio_fprintf(defaultStream::error_stream(),
1793 "\nException: %s thrown from the UncaughtExceptionHandler"
1794 " in thread \"%s\"\n",
1795 pending_exception()->klass()->external_name(),
1796 get_thread_name());
1797 CLEAR_PENDING_EXCEPTION;
1798 }
1799 }
1800 }
1801
1802 // Called before the java thread exit since we want to read info
1803 // from java_lang_Thread object
1804 EventThreadEnd event;
1805 if (event.should_commit()) {
1806 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1807 event.commit();
1808 }
1809
1810 // Call after last event on thread
1811 EVENT_THREAD_EXIT(this);
1812
1813 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1814 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1815 // is deprecated anyhow.
1816 { int count = 3;
1817 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1818 EXCEPTION_MARK;
1819 JavaValue result(T_VOID);
1820 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1821 JavaCalls::call_virtual(&result,
1822 threadObj, thread_klass,
1823 vmSymbols::exit_method_name(),
1824 vmSymbols::void_method_signature(),
1825 THREAD);
1826 CLEAR_PENDING_EXCEPTION;
1827 }
1828 }
1829
1830 // notify JVMTI
1831 if (JvmtiExport::should_post_thread_life()) {
1832 JvmtiExport::post_thread_end(this);
1833 }
1834
1835 // We have notified the agents that we are exiting, before we go on,
1836 // we must check for a pending external suspend request and honor it
1837 // in order to not surprise the thread that made the suspend request.
1838 while (true) {
1839 {
1840 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1841 if (!is_external_suspend()) {
1842 set_terminated(_thread_exiting);
1843 ThreadService::current_thread_exiting(this);
1844 break;
1845 }
1846 // Implied else:
1847 // Things get a little tricky here. We have a pending external
1848 // suspend request, but we are holding the SR_lock so we
1849 // can't just self-suspend. So we temporarily drop the lock
1850 // and then self-suspend.
1851 }
1852
1853 ThreadBlockInVM tbivm(this);
1854 java_suspend_self();
1855
1856 // We're done with this suspend request, but we have to loop around
1857 // and check again. Eventually we will get SR_lock without a pending
1858 // external suspend request and will be able to mark ourselves as
1859 // exiting.
1860 }
1861 // no more external suspends are allowed at this point
1862 } else {
1863 // before_exit() has already posted JVMTI THREAD_END events
1864 }
1865
1866 // Notify waiters on thread object. This has to be done after exit() is called
1867 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1868 // group should have the destroyed bit set before waiters are notified).
1869 ensure_join(this);
1870 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1871
1872 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1873 // held by this thread must be released. A detach operation must only
1874 // get here if there are no Java frames on the stack. Therefore, any
1875 // owned monitors at this point MUST be JNI-acquired monitors which are
1876 // pre-inflated and in the monitor cache.
1877 //
1878 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1879 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1880 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1881 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1882 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1883 }
1884
1885 // These things needs to be done while we are still a Java Thread. Make sure that thread
1886 // is in a consistent state, in case GC happens
1887 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1888
1889 if (active_handles() != NULL) {
1890 JNIHandleBlock* block = active_handles();
1891 set_active_handles(NULL);
1892 JNIHandleBlock::release_block(block);
1893 }
1894
1895 if (free_handle_block() != NULL) {
1896 JNIHandleBlock* block = free_handle_block();
1897 set_free_handle_block(NULL);
1898 JNIHandleBlock::release_block(block);
1899 }
1900
1901 // These have to be removed while this is still a valid thread.
1902 remove_stack_guard_pages();
1903
1904 if (UseTLAB) {
1905 tlab().make_parsable(true); // retire TLAB
1906 }
1907
1908 if (JvmtiEnv::environments_might_exist()) {
1909 JvmtiExport::cleanup_thread(this);
1910 }
1911
1912 // We must flush any deferred card marks before removing a thread from
1913 // the list of active threads.
1914 Universe::heap()->flush_deferred_store_barrier(this);
1915 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1916
1917 #if INCLUDE_ALL_GCS
1918 // We must flush the G1-related buffers before removing a thread
1919 // from the list of active threads. We must do this after any deferred
1920 // card marks have been flushed (above) so that any entries that are
1921 // added to the thread's dirty card queue as a result are not lost.
1922 if (UseG1GC) {
1923 flush_barrier_queues();
1924 }
1925 #endif // INCLUDE_ALL_GCS
1926
1927 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1928 Threads::remove(this);
1929 }
1930
1931 #if INCLUDE_ALL_GCS
1932 // Flush G1-related queues.
1933 void JavaThread::flush_barrier_queues() {
1934 satb_mark_queue().flush();
1935 dirty_card_queue().flush();
1936 }
1937
1938 void JavaThread::initialize_queues() {
1939 assert(!SafepointSynchronize::is_at_safepoint(),
1940 "we should not be at a safepoint");
1941
1942 ObjPtrQueue& satb_queue = satb_mark_queue();
1943 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1944 // The SATB queue should have been constructed with its active
1945 // field set to false.
1946 assert(!satb_queue.is_active(), "SATB queue should not be active");
1947 assert(satb_queue.is_empty(), "SATB queue should be empty");
1948 // If we are creating the thread during a marking cycle, we should
1949 // set the active field of the SATB queue to true.
1950 if (satb_queue_set.is_active()) {
1951 satb_queue.set_active(true);
1952 }
1953
1954 DirtyCardQueue& dirty_queue = dirty_card_queue();
1955 // The dirty card queue should have been constructed with its
1956 // active field set to true.
1957 assert(dirty_queue.is_active(), "dirty card queue should be active");
1958 }
1959 #endif // INCLUDE_ALL_GCS
1960
1961 void JavaThread::cleanup_failed_attach_current_thread() {
1962 if (get_thread_profiler() != NULL) {
1963 get_thread_profiler()->disengage();
1964 ResourceMark rm;
1965 get_thread_profiler()->print(get_thread_name());
1966 }
1967
1968 if (active_handles() != NULL) {
1969 JNIHandleBlock* block = active_handles();
1970 set_active_handles(NULL);
1971 JNIHandleBlock::release_block(block);
1972 }
1973
1974 if (free_handle_block() != NULL) {
1975 JNIHandleBlock* block = free_handle_block();
1976 set_free_handle_block(NULL);
1977 JNIHandleBlock::release_block(block);
1978 }
1979
1980 // These have to be removed while this is still a valid thread.
1981 remove_stack_guard_pages();
1982
1983 if (UseTLAB) {
1984 tlab().make_parsable(true); // retire TLAB, if any
1985 }
1986
1987 #if INCLUDE_ALL_GCS
1988 if (UseG1GC) {
1989 flush_barrier_queues();
1990 }
1991 #endif // INCLUDE_ALL_GCS
1992
1993 Threads::remove(this);
1994 delete this;
1995 }
1996
1997
1998
1999
2000 JavaThread* JavaThread::active() {
2001 Thread* thread = ThreadLocalStorage::thread();
2002 assert(thread != NULL, "just checking");
2003 if (thread->is_Java_thread()) {
2004 return (JavaThread*) thread;
2005 } else {
2006 assert(thread->is_VM_thread(), "this must be a vm thread");
2007 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2008 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2009 assert(ret->is_Java_thread(), "must be a Java thread");
2010 return ret;
2011 }
2012 }
2013
2014 bool JavaThread::is_lock_owned(address adr) const {
2015 if (Thread::is_lock_owned(adr)) return true;
2016
2017 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2018 if (chunk->contains(adr)) return true;
2019 }
2020
2021 return false;
2022 }
2023
2024
2025 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2026 chunk->set_next(monitor_chunks());
2027 set_monitor_chunks(chunk);
2028 }
2029
2030 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2031 guarantee(monitor_chunks() != NULL, "must be non empty");
2032 if (monitor_chunks() == chunk) {
2033 set_monitor_chunks(chunk->next());
2034 } else {
2035 MonitorChunk* prev = monitor_chunks();
2036 while (prev->next() != chunk) prev = prev->next();
2037 prev->set_next(chunk->next());
2038 }
2039 }
2040
2041 // JVM support.
2042
2043 // Note: this function shouldn't block if it's called in
2044 // _thread_in_native_trans state (such as from
2045 // check_special_condition_for_native_trans()).
2046 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2047
2048 if (has_last_Java_frame() && has_async_condition()) {
2049 // If we are at a polling page safepoint (not a poll return)
2050 // then we must defer async exception because live registers
2051 // will be clobbered by the exception path. Poll return is
2052 // ok because the call we a returning from already collides
2053 // with exception handling registers and so there is no issue.
2054 // (The exception handling path kills call result registers but
2055 // this is ok since the exception kills the result anyway).
2056
2057 if (is_at_poll_safepoint()) {
2058 // if the code we are returning to has deoptimized we must defer
2059 // the exception otherwise live registers get clobbered on the
2060 // exception path before deoptimization is able to retrieve them.
2061 //
2062 RegisterMap map(this, false);
2063 frame caller_fr = last_frame().sender(&map);
2064 assert(caller_fr.is_compiled_frame(), "what?");
2065 if (caller_fr.is_deoptimized_frame()) {
2066 if (TraceExceptions) {
2067 ResourceMark rm;
2068 tty->print_cr("deferred async exception at compiled safepoint");
2069 }
2070 return;
2071 }
2072 }
2073 }
2074
2075 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2076 if (condition == _no_async_condition) {
2077 // Conditions have changed since has_special_runtime_exit_condition()
2078 // was called:
2079 // - if we were here only because of an external suspend request,
2080 // then that was taken care of above (or cancelled) so we are done
2081 // - if we were here because of another async request, then it has
2082 // been cleared between the has_special_runtime_exit_condition()
2083 // and now so again we are done
2084 return;
2085 }
2086
2087 // Check for pending async. exception
2088 if (_pending_async_exception != NULL) {
2089 // Only overwrite an already pending exception, if it is not a threadDeath.
2090 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2091
2092 // We cannot call Exceptions::_throw(...) here because we cannot block
2093 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2094
2095 if (TraceExceptions) {
2096 ResourceMark rm;
2097 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2098 if (has_last_Java_frame() ) {
2099 frame f = last_frame();
2100 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2101 }
2102 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2103 }
2104 _pending_async_exception = NULL;
2105 clear_has_async_exception();
2106 }
2107 }
2108
2109 if (check_unsafe_error &&
2110 condition == _async_unsafe_access_error && !has_pending_exception()) {
2111 condition = _no_async_condition; // done
2112 switch (thread_state()) {
2113 case _thread_in_vm:
2114 {
2115 JavaThread* THREAD = this;
2116 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2117 }
2118 case _thread_in_native:
2119 {
2120 ThreadInVMfromNative tiv(this);
2121 JavaThread* THREAD = this;
2122 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2123 }
2124 case _thread_in_Java:
2125 {
2126 ThreadInVMfromJava tiv(this);
2127 JavaThread* THREAD = this;
2128 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2129 }
2130 default:
2131 ShouldNotReachHere();
2132 }
2133 }
2134
2135 assert(condition == _no_async_condition || has_pending_exception() ||
2136 (!check_unsafe_error && condition == _async_unsafe_access_error),
2137 "must have handled the async condition, if no exception");
2138 }
2139
2140 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2141 //
2142 // Check for pending external suspend. Internal suspend requests do
2143 // not use handle_special_runtime_exit_condition().
2144 // If JNIEnv proxies are allowed, don't self-suspend if the target
2145 // thread is not the current thread. In older versions of jdbx, jdbx
2146 // threads could call into the VM with another thread's JNIEnv so we
2147 // can be here operating on behalf of a suspended thread (4432884).
2148 bool do_self_suspend = is_external_suspend_with_lock();
2149 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2150 //
2151 // Because thread is external suspended the safepoint code will count
2152 // thread as at a safepoint. This can be odd because we can be here
2153 // as _thread_in_Java which would normally transition to _thread_blocked
2154 // at a safepoint. We would like to mark the thread as _thread_blocked
2155 // before calling java_suspend_self like all other callers of it but
2156 // we must then observe proper safepoint protocol. (We can't leave
2157 // _thread_blocked with a safepoint in progress). However we can be
2158 // here as _thread_in_native_trans so we can't use a normal transition
2159 // constructor/destructor pair because they assert on that type of
2160 // transition. We could do something like:
2161 //
2162 // JavaThreadState state = thread_state();
2163 // set_thread_state(_thread_in_vm);
2164 // {
2165 // ThreadBlockInVM tbivm(this);
2166 // java_suspend_self()
2167 // }
2168 // set_thread_state(_thread_in_vm_trans);
2169 // if (safepoint) block;
2170 // set_thread_state(state);
2171 //
2172 // but that is pretty messy. Instead we just go with the way the
2173 // code has worked before and note that this is the only path to
2174 // java_suspend_self that doesn't put the thread in _thread_blocked
2175 // mode.
2176
2177 frame_anchor()->make_walkable(this);
2178 java_suspend_self();
2179
2180 // We might be here for reasons in addition to the self-suspend request
2181 // so check for other async requests.
2182 }
2183
2184 if (check_asyncs) {
2185 check_and_handle_async_exceptions();
2186 }
2187 }
2188
2189 void JavaThread::send_thread_stop(oop java_throwable) {
2190 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2191 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2192 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2193
2194 // Do not throw asynchronous exceptions against the compiler thread
2195 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2196 if (is_Compiler_thread()) return;
2197
2198 {
2199 // Actually throw the Throwable against the target Thread - however
2200 // only if there is no thread death exception installed already.
2201 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2202 // If the topmost frame is a runtime stub, then we are calling into
2203 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2204 // must deoptimize the caller before continuing, as the compiled exception handler table
2205 // may not be valid
2206 if (has_last_Java_frame()) {
2207 frame f = last_frame();
2208 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2209 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2210 RegisterMap reg_map(this, UseBiasedLocking);
2211 frame compiled_frame = f.sender(®_map);
2212 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2213 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2214 }
2215 }
2216 }
2217
2218 // Set async. pending exception in thread.
2219 set_pending_async_exception(java_throwable);
2220
2221 if (TraceExceptions) {
2222 ResourceMark rm;
2223 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2224 }
2225 // for AbortVMOnException flag
2226 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2227 }
2228 }
2229
2230
2231 // Interrupt thread so it will wake up from a potential wait()
2232 Thread::interrupt(this);
2233 }
2234
2235 // External suspension mechanism.
2236 //
2237 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2238 // to any VM_locks and it is at a transition
2239 // Self-suspension will happen on the transition out of the vm.
2240 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2241 //
2242 // Guarantees on return:
2243 // + Target thread will not execute any new bytecode (that's why we need to
2244 // force a safepoint)
2245 // + Target thread will not enter any new monitors
2246 //
2247 void JavaThread::java_suspend() {
2248 { MutexLocker mu(Threads_lock);
2249 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2250 return;
2251 }
2252 }
2253
2254 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2255 if (!is_external_suspend()) {
2256 // a racing resume has cancelled us; bail out now
2257 return;
2258 }
2259
2260 // suspend is done
2261 uint32_t debug_bits = 0;
2262 // Warning: is_ext_suspend_completed() may temporarily drop the
2263 // SR_lock to allow the thread to reach a stable thread state if
2264 // it is currently in a transient thread state.
2265 if (is_ext_suspend_completed(false /* !called_by_wait */,
2266 SuspendRetryDelay, &debug_bits) ) {
2267 return;
2268 }
2269 }
2270
2271 VM_ForceSafepoint vm_suspend;
2272 VMThread::execute(&vm_suspend);
2273 }
2274
2275 // Part II of external suspension.
2276 // A JavaThread self suspends when it detects a pending external suspend
2277 // request. This is usually on transitions. It is also done in places
2278 // where continuing to the next transition would surprise the caller,
2279 // e.g., monitor entry.
2280 //
2281 // Returns the number of times that the thread self-suspended.
2282 //
2283 // Note: DO NOT call java_suspend_self() when you just want to block current
2284 // thread. java_suspend_self() is the second stage of cooperative
2285 // suspension for external suspend requests and should only be used
2286 // to complete an external suspend request.
2287 //
2288 int JavaThread::java_suspend_self() {
2289 int ret = 0;
2290
2291 // we are in the process of exiting so don't suspend
2292 if (is_exiting()) {
2293 clear_external_suspend();
2294 return ret;
2295 }
2296
2297 assert(_anchor.walkable() ||
2298 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2299 "must have walkable stack");
2300
2301 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2302
2303 assert(!this->is_ext_suspended(),
2304 "a thread trying to self-suspend should not already be suspended");
2305
2306 if (this->is_suspend_equivalent()) {
2307 // If we are self-suspending as a result of the lifting of a
2308 // suspend equivalent condition, then the suspend_equivalent
2309 // flag is not cleared until we set the ext_suspended flag so
2310 // that wait_for_ext_suspend_completion() returns consistent
2311 // results.
2312 this->clear_suspend_equivalent();
2313 }
2314
2315 // A racing resume may have cancelled us before we grabbed SR_lock
2316 // above. Or another external suspend request could be waiting for us
2317 // by the time we return from SR_lock()->wait(). The thread
2318 // that requested the suspension may already be trying to walk our
2319 // stack and if we return now, we can change the stack out from under
2320 // it. This would be a "bad thing (TM)" and cause the stack walker
2321 // to crash. We stay self-suspended until there are no more pending
2322 // external suspend requests.
2323 while (is_external_suspend()) {
2324 ret++;
2325 this->set_ext_suspended();
2326
2327 // _ext_suspended flag is cleared by java_resume()
2328 while (is_ext_suspended()) {
2329 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2330 }
2331 }
2332
2333 return ret;
2334 }
2335
2336 #ifdef ASSERT
2337 // verify the JavaThread has not yet been published in the Threads::list, and
2338 // hence doesn't need protection from concurrent access at this stage
2339 void JavaThread::verify_not_published() {
2340 if (!Threads_lock->owned_by_self()) {
2341 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2342 assert( !Threads::includes(this),
2343 "java thread shouldn't have been published yet!");
2344 }
2345 else {
2346 assert( !Threads::includes(this),
2347 "java thread shouldn't have been published yet!");
2348 }
2349 }
2350 #endif
2351
2352 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2353 // progress or when _suspend_flags is non-zero.
2354 // Current thread needs to self-suspend if there is a suspend request and/or
2355 // block if a safepoint is in progress.
2356 // Async exception ISN'T checked.
2357 // Note only the ThreadInVMfromNative transition can call this function
2358 // directly and when thread state is _thread_in_native_trans
2359 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2360 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2361
2362 JavaThread *curJT = JavaThread::current();
2363 bool do_self_suspend = thread->is_external_suspend();
2364
2365 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2366
2367 // If JNIEnv proxies are allowed, don't self-suspend if the target
2368 // thread is not the current thread. In older versions of jdbx, jdbx
2369 // threads could call into the VM with another thread's JNIEnv so we
2370 // can be here operating on behalf of a suspended thread (4432884).
2371 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2372 JavaThreadState state = thread->thread_state();
2373
2374 // We mark this thread_blocked state as a suspend-equivalent so
2375 // that a caller to is_ext_suspend_completed() won't be confused.
2376 // The suspend-equivalent state is cleared by java_suspend_self().
2377 thread->set_suspend_equivalent();
2378
2379 // If the safepoint code sees the _thread_in_native_trans state, it will
2380 // wait until the thread changes to other thread state. There is no
2381 // guarantee on how soon we can obtain the SR_lock and complete the
2382 // self-suspend request. It would be a bad idea to let safepoint wait for
2383 // too long. Temporarily change the state to _thread_blocked to
2384 // let the VM thread know that this thread is ready for GC. The problem
2385 // of changing thread state is that safepoint could happen just after
2386 // java_suspend_self() returns after being resumed, and VM thread will
2387 // see the _thread_blocked state. We must check for safepoint
2388 // after restoring the state and make sure we won't leave while a safepoint
2389 // is in progress.
2390 thread->set_thread_state(_thread_blocked);
2391 thread->java_suspend_self();
2392 thread->set_thread_state(state);
2393 // Make sure new state is seen by VM thread
2394 if (os::is_MP()) {
2395 if (UseMembar) {
2396 // Force a fence between the write above and read below
2397 OrderAccess::fence();
2398 } else {
2399 // Must use this rather than serialization page in particular on Windows
2400 InterfaceSupport::serialize_memory(thread);
2401 }
2402 }
2403 }
2404
2405 if (SafepointSynchronize::do_call_back()) {
2406 // If we are safepointing, then block the caller which may not be
2407 // the same as the target thread (see above).
2408 SafepointSynchronize::block(curJT);
2409 }
2410
2411 if (thread->is_deopt_suspend()) {
2412 thread->clear_deopt_suspend();
2413 RegisterMap map(thread, false);
2414 frame f = thread->last_frame();
2415 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2416 f = f.sender(&map);
2417 }
2418 if (f.id() == thread->must_deopt_id()) {
2419 thread->clear_must_deopt_id();
2420 f.deoptimize(thread);
2421 } else {
2422 fatal("missed deoptimization!");
2423 }
2424 }
2425 }
2426
2427 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2428 // progress or when _suspend_flags is non-zero.
2429 // Current thread needs to self-suspend if there is a suspend request and/or
2430 // block if a safepoint is in progress.
2431 // Also check for pending async exception (not including unsafe access error).
2432 // Note only the native==>VM/Java barriers can call this function and when
2433 // thread state is _thread_in_native_trans.
2434 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2435 check_safepoint_and_suspend_for_native_trans(thread);
2436
2437 if (thread->has_async_exception()) {
2438 // We are in _thread_in_native_trans state, don't handle unsafe
2439 // access error since that may block.
2440 thread->check_and_handle_async_exceptions(false);
2441 }
2442 }
2443
2444 // This is a variant of the normal
2445 // check_special_condition_for_native_trans with slightly different
2446 // semantics for use by critical native wrappers. It does all the
2447 // normal checks but also performs the transition back into
2448 // thread_in_Java state. This is required so that critical natives
2449 // can potentially block and perform a GC if they are the last thread
2450 // exiting the GC_locker.
2451 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2452 check_special_condition_for_native_trans(thread);
2453
2454 // Finish the transition
2455 thread->set_thread_state(_thread_in_Java);
2456
2457 if (thread->do_critical_native_unlock()) {
2458 ThreadInVMfromJavaNoAsyncException tiv(thread);
2459 GC_locker::unlock_critical(thread);
2460 thread->clear_critical_native_unlock();
2461 }
2462 }
2463
2464 // We need to guarantee the Threads_lock here, since resumes are not
2465 // allowed during safepoint synchronization
2466 // Can only resume from an external suspension
2467 void JavaThread::java_resume() {
2468 assert_locked_or_safepoint(Threads_lock);
2469
2470 // Sanity check: thread is gone, has started exiting or the thread
2471 // was not externally suspended.
2472 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2473 return;
2474 }
2475
2476 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2477
2478 clear_external_suspend();
2479
2480 if (is_ext_suspended()) {
2481 clear_ext_suspended();
2482 SR_lock()->notify_all();
2483 }
2484 }
2485
2486 void JavaThread::create_stack_guard_pages() {
2487 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2488 address low_addr = stack_base() - stack_size();
2489 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2490
2491 int allocate = os::allocate_stack_guard_pages();
2492 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2493
2494 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2495 warning("Attempt to allocate stack guard pages failed.");
2496 return;
2497 }
2498
2499 if (os::guard_memory((char *) low_addr, len)) {
2500 _stack_guard_state = stack_guard_enabled;
2501 } else {
2502 warning("Attempt to protect stack guard pages failed.");
2503 if (os::uncommit_memory((char *) low_addr, len)) {
2504 warning("Attempt to deallocate stack guard pages failed.");
2505 }
2506 }
2507 }
2508
2509 void JavaThread::remove_stack_guard_pages() {
2510 assert(Thread::current() == this, "from different thread");
2511 if (_stack_guard_state == stack_guard_unused) return;
2512 address low_addr = stack_base() - stack_size();
2513 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2514
2515 if (os::allocate_stack_guard_pages()) {
2516 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2517 _stack_guard_state = stack_guard_unused;
2518 } else {
2519 warning("Attempt to deallocate stack guard pages failed.");
2520 }
2521 } else {
2522 if (_stack_guard_state == stack_guard_unused) return;
2523 if (os::unguard_memory((char *) low_addr, len)) {
2524 _stack_guard_state = stack_guard_unused;
2525 } else {
2526 warning("Attempt to unprotect stack guard pages failed.");
2527 }
2528 }
2529 }
2530
2531 void JavaThread::enable_stack_yellow_zone() {
2532 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2533 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2534
2535 // The base notation is from the stacks point of view, growing downward.
2536 // We need to adjust it to work correctly with guard_memory()
2537 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2538
2539 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2540 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2541
2542 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2543 _stack_guard_state = stack_guard_enabled;
2544 } else {
2545 warning("Attempt to guard stack yellow zone failed.");
2546 }
2547 enable_register_stack_guard();
2548 }
2549
2550 void JavaThread::disable_stack_yellow_zone() {
2551 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2552 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2553
2554 // Simply return if called for a thread that does not use guard pages.
2555 if (_stack_guard_state == stack_guard_unused) return;
2556
2557 // The base notation is from the stacks point of view, growing downward.
2558 // We need to adjust it to work correctly with guard_memory()
2559 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2560
2561 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2562 _stack_guard_state = stack_guard_yellow_disabled;
2563 } else {
2564 warning("Attempt to unguard stack yellow zone failed.");
2565 }
2566 disable_register_stack_guard();
2567 }
2568
2569 void JavaThread::enable_stack_red_zone() {
2570 // The base notation is from the stacks point of view, growing downward.
2571 // We need to adjust it to work correctly with guard_memory()
2572 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2573 address base = stack_red_zone_base() - stack_red_zone_size();
2574
2575 guarantee(base < stack_base(),"Error calculating stack red zone");
2576 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2577
2578 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2579 warning("Attempt to guard stack red zone failed.");
2580 }
2581 }
2582
2583 void JavaThread::disable_stack_red_zone() {
2584 // The base notation is from the stacks point of view, growing downward.
2585 // We need to adjust it to work correctly with guard_memory()
2586 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2587 address base = stack_red_zone_base() - stack_red_zone_size();
2588 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2589 warning("Attempt to unguard stack red zone failed.");
2590 }
2591 }
2592
2593 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2594 // ignore is there is no stack
2595 if (!has_last_Java_frame()) return;
2596 // traverse the stack frames. Starts from top frame.
2597 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2598 frame* fr = fst.current();
2599 f(fr, fst.register_map());
2600 }
2601 }
2602
2603
2604 #ifndef PRODUCT
2605 // Deoptimization
2606 // Function for testing deoptimization
2607 void JavaThread::deoptimize() {
2608 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2609 StackFrameStream fst(this, UseBiasedLocking);
2610 bool deopt = false; // Dump stack only if a deopt actually happens.
2611 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2612 // Iterate over all frames in the thread and deoptimize
2613 for(; !fst.is_done(); fst.next()) {
2614 if(fst.current()->can_be_deoptimized()) {
2615
2616 if (only_at) {
2617 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2618 // consists of comma or carriage return separated numbers so
2619 // search for the current bci in that string.
2620 address pc = fst.current()->pc();
2621 nmethod* nm = (nmethod*) fst.current()->cb();
2622 ScopeDesc* sd = nm->scope_desc_at( pc);
2623 char buffer[8];
2624 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2625 size_t len = strlen(buffer);
2626 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2627 while (found != NULL) {
2628 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2629 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2630 // Check that the bci found is bracketed by terminators.
2631 break;
2632 }
2633 found = strstr(found + 1, buffer);
2634 }
2635 if (!found) {
2636 continue;
2637 }
2638 }
2639
2640 if (DebugDeoptimization && !deopt) {
2641 deopt = true; // One-time only print before deopt
2642 tty->print_cr("[BEFORE Deoptimization]");
2643 trace_frames();
2644 trace_stack();
2645 }
2646 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2647 }
2648 }
2649
2650 if (DebugDeoptimization && deopt) {
2651 tty->print_cr("[AFTER Deoptimization]");
2652 trace_frames();
2653 }
2654 }
2655
2656
2657 // Make zombies
2658 void JavaThread::make_zombies() {
2659 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2660 if (fst.current()->can_be_deoptimized()) {
2661 // it is a Java nmethod
2662 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2663 nm->make_not_entrant();
2664 }
2665 }
2666 }
2667 #endif // PRODUCT
2668
2669
2670 void JavaThread::deoptimized_wrt_marked_nmethods() {
2671 if (!has_last_Java_frame()) return;
2672 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2673 StackFrameStream fst(this, UseBiasedLocking);
2674 for(; !fst.is_done(); fst.next()) {
2675 if (fst.current()->should_be_deoptimized()) {
2676 if (LogCompilation && xtty != NULL) {
2677 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2678 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2679 this->name(), nm != NULL ? nm->compile_id() : -1);
2680 }
2681
2682 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2683 }
2684 }
2685 }
2686
2687
2688 // GC support
2689 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2690
2691 void JavaThread::gc_epilogue() {
2692 frames_do(frame_gc_epilogue);
2693 }
2694
2695
2696 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2697
2698 void JavaThread::gc_prologue() {
2699 frames_do(frame_gc_prologue);
2700 }
2701
2702 // If the caller is a NamedThread, then remember, in the current scope,
2703 // the given JavaThread in its _processed_thread field.
2704 class RememberProcessedThread: public StackObj {
2705 NamedThread* _cur_thr;
2706 public:
2707 RememberProcessedThread(JavaThread* jthr) {
2708 Thread* thread = Thread::current();
2709 if (thread->is_Named_thread()) {
2710 _cur_thr = (NamedThread *)thread;
2711 _cur_thr->set_processed_thread(jthr);
2712 } else {
2713 _cur_thr = NULL;
2714 }
2715 }
2716
2717 ~RememberProcessedThread() {
2718 if (_cur_thr) {
2719 _cur_thr->set_processed_thread(NULL);
2720 }
2721 }
2722 };
2723
2724 void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
2725 // Verify that the deferred card marks have been flushed.
2726 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2727
2728 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2729 // since there may be more than one thread using each ThreadProfiler.
2730
2731 // Traverse the GCHandles
2732 Thread::oops_do(f, cld_f, cf);
2733
2734 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2735 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2736
2737 if (has_last_Java_frame()) {
2738 // Record JavaThread to GC thread
2739 RememberProcessedThread rpt(this);
2740
2741 // Traverse the privileged stack
2742 if (_privileged_stack_top != NULL) {
2743 _privileged_stack_top->oops_do(f);
2744 }
2745
2746 // traverse the registered growable array
2747 if (_array_for_gc != NULL) {
2748 for (int index = 0; index < _array_for_gc->length(); index++) {
2749 f->do_oop(_array_for_gc->adr_at(index));
2750 }
2751 }
2752
2753 // Traverse the monitor chunks
2754 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2755 chunk->oops_do(f);
2756 }
2757
2758 // Traverse the execution stack
2759 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2760 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2761 }
2762 }
2763
2764 // callee_target is never live across a gc point so NULL it here should
2765 // it still contain a methdOop.
2766
2767 set_callee_target(NULL);
2768
2769 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2770 // If we have deferred set_locals there might be oops waiting to be
2771 // written
2772 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2773 if (list != NULL) {
2774 for (int i = 0; i < list->length(); i++) {
2775 list->at(i)->oops_do(f);
2776 }
2777 }
2778
2779 // Traverse instance variables at the end since the GC may be moving things
2780 // around using this function
2781 f->do_oop((oop*) &_threadObj);
2782 f->do_oop((oop*) &_vm_result);
2783 f->do_oop((oop*) &_exception_oop);
2784 f->do_oop((oop*) &_pending_async_exception);
2785
2786 if (jvmti_thread_state() != NULL) {
2787 jvmti_thread_state()->oops_do(f);
2788 }
2789 }
2790
2791 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2792 Thread::nmethods_do(cf); // (super method is a no-op)
2793
2794 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2795 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2796
2797 if (has_last_Java_frame()) {
2798 // Traverse the execution stack
2799 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2800 fst.current()->nmethods_do(cf);
2801 }
2802 }
2803 }
2804
2805 void JavaThread::metadata_do(void f(Metadata*)) {
2806 Thread::metadata_do(f);
2807 if (has_last_Java_frame()) {
2808 // Traverse the execution stack to call f() on the methods in the stack
2809 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2810 fst.current()->metadata_do(f);
2811 }
2812 } else if (is_Compiler_thread()) {
2813 // need to walk ciMetadata in current compile tasks to keep alive.
2814 CompilerThread* ct = (CompilerThread*)this;
2815 if (ct->env() != NULL) {
2816 ct->env()->metadata_do(f);
2817 }
2818 }
2819 }
2820
2821 // Printing
2822 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2823 switch (_thread_state) {
2824 case _thread_uninitialized: return "_thread_uninitialized";
2825 case _thread_new: return "_thread_new";
2826 case _thread_new_trans: return "_thread_new_trans";
2827 case _thread_in_native: return "_thread_in_native";
2828 case _thread_in_native_trans: return "_thread_in_native_trans";
2829 case _thread_in_vm: return "_thread_in_vm";
2830 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2831 case _thread_in_Java: return "_thread_in_Java";
2832 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2833 case _thread_blocked: return "_thread_blocked";
2834 case _thread_blocked_trans: return "_thread_blocked_trans";
2835 default: return "unknown thread state";
2836 }
2837 }
2838
2839 #ifndef PRODUCT
2840 void JavaThread::print_thread_state_on(outputStream *st) const {
2841 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2842 };
2843 void JavaThread::print_thread_state() const {
2844 print_thread_state_on(tty);
2845 };
2846 #endif // PRODUCT
2847
2848 // Called by Threads::print() for VM_PrintThreads operation
2849 void JavaThread::print_on(outputStream *st) const {
2850 st->print("\"%s\" ", get_thread_name());
2851 oop thread_oop = threadObj();
2852 if (thread_oop != NULL) {
2853 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2854 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2855 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2856 }
2857 Thread::print_on(st);
2858 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2859 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2860 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2861 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2862 }
2863 #ifndef PRODUCT
2864 print_thread_state_on(st);
2865 _safepoint_state->print_on(st);
2866 #endif // PRODUCT
2867 }
2868
2869 // Called by fatal error handler. The difference between this and
2870 // JavaThread::print() is that we can't grab lock or allocate memory.
2871 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2872 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2873 oop thread_obj = threadObj();
2874 if (thread_obj != NULL) {
2875 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2876 }
2877 st->print(" [");
2878 st->print("%s", _get_thread_state_name(_thread_state));
2879 if (osthread()) {
2880 st->print(", id=%d", osthread()->thread_id());
2881 }
2882 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2883 _stack_base - _stack_size, _stack_base);
2884 st->print("]");
2885 return;
2886 }
2887
2888 // Verification
2889
2890 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2891
2892 void JavaThread::verify() {
2893 // Verify oops in the thread.
2894 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2895
2896 // Verify the stack frames.
2897 frames_do(frame_verify);
2898 }
2899
2900 // CR 6300358 (sub-CR 2137150)
2901 // Most callers of this method assume that it can't return NULL but a
2902 // thread may not have a name whilst it is in the process of attaching to
2903 // the VM - see CR 6412693, and there are places where a JavaThread can be
2904 // seen prior to having it's threadObj set (eg JNI attaching threads and
2905 // if vm exit occurs during initialization). These cases can all be accounted
2906 // for such that this method never returns NULL.
2907 const char* JavaThread::get_thread_name() const {
2908 #ifdef ASSERT
2909 // early safepoints can hit while current thread does not yet have TLS
2910 if (!SafepointSynchronize::is_at_safepoint()) {
2911 Thread *cur = Thread::current();
2912 if (!(cur->is_Java_thread() && cur == this)) {
2913 // Current JavaThreads are allowed to get their own name without
2914 // the Threads_lock.
2915 assert_locked_or_safepoint(Threads_lock);
2916 }
2917 }
2918 #endif // ASSERT
2919 return get_thread_name_string();
2920 }
2921
2922 // Returns a non-NULL representation of this thread's name, or a suitable
2923 // descriptive string if there is no set name
2924 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2925 const char* name_str;
2926 oop thread_obj = threadObj();
2927 if (thread_obj != NULL) {
2928 typeArrayOop name = java_lang_Thread::name(thread_obj);
2929 if (name != NULL) {
2930 if (buf == NULL) {
2931 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2932 }
2933 else {
2934 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2935 }
2936 }
2937 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2938 name_str = "<no-name - thread is attaching>";
2939 }
2940 else {
2941 name_str = Thread::name();
2942 }
2943 }
2944 else {
2945 name_str = Thread::name();
2946 }
2947 assert(name_str != NULL, "unexpected NULL thread name");
2948 return name_str;
2949 }
2950
2951
2952 const char* JavaThread::get_threadgroup_name() const {
2953 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2954 oop thread_obj = threadObj();
2955 if (thread_obj != NULL) {
2956 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2957 if (thread_group != NULL) {
2958 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2959 // ThreadGroup.name can be null
2960 if (name != NULL) {
2961 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2962 return str;
2963 }
2964 }
2965 }
2966 return NULL;
2967 }
2968
2969 const char* JavaThread::get_parent_name() const {
2970 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2971 oop thread_obj = threadObj();
2972 if (thread_obj != NULL) {
2973 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2974 if (thread_group != NULL) {
2975 oop parent = java_lang_ThreadGroup::parent(thread_group);
2976 if (parent != NULL) {
2977 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2978 // ThreadGroup.name can be null
2979 if (name != NULL) {
2980 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2981 return str;
2982 }
2983 }
2984 }
2985 }
2986 return NULL;
2987 }
2988
2989 ThreadPriority JavaThread::java_priority() const {
2990 oop thr_oop = threadObj();
2991 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2992 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2993 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2994 return priority;
2995 }
2996
2997 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2998
2999 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3000 // Link Java Thread object <-> C++ Thread
3001
3002 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3003 // and put it into a new Handle. The Handle "thread_oop" can then
3004 // be used to pass the C++ thread object to other methods.
3005
3006 // Set the Java level thread object (jthread) field of the
3007 // new thread (a JavaThread *) to C++ thread object using the
3008 // "thread_oop" handle.
3009
3010 // Set the thread field (a JavaThread *) of the
3011 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3012
3013 Handle thread_oop(Thread::current(),
3014 JNIHandles::resolve_non_null(jni_thread));
3015 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3016 "must be initialized");
3017 set_threadObj(thread_oop());
3018 java_lang_Thread::set_thread(thread_oop(), this);
3019
3020 if (prio == NoPriority) {
3021 prio = java_lang_Thread::priority(thread_oop());
3022 assert(prio != NoPriority, "A valid priority should be present");
3023 }
3024
3025 // Push the Java priority down to the native thread; needs Threads_lock
3026 Thread::set_priority(this, prio);
3027
3028 // Add the new thread to the Threads list and set it in motion.
3029 // We must have threads lock in order to call Threads::add.
3030 // It is crucial that we do not block before the thread is
3031 // added to the Threads list for if a GC happens, then the java_thread oop
3032 // will not be visited by GC.
3033 Threads::add(this);
3034 }
3035
3036 oop JavaThread::current_park_blocker() {
3037 // Support for JSR-166 locks
3038 oop thread_oop = threadObj();
3039 if (thread_oop != NULL &&
3040 JDK_Version::current().supports_thread_park_blocker()) {
3041 return java_lang_Thread::park_blocker(thread_oop);
3042 }
3043 return NULL;
3044 }
3045
3046
3047 void JavaThread::print_stack_on(outputStream* st) {
3048 if (!has_last_Java_frame()) return;
3049 ResourceMark rm;
3050 HandleMark hm;
3051
3052 RegisterMap reg_map(this);
3053 vframe* start_vf = last_java_vframe(®_map);
3054 int count = 0;
3055 for (vframe* f = start_vf; f; f = f->sender() ) {
3056 if (f->is_java_frame()) {
3057 javaVFrame* jvf = javaVFrame::cast(f);
3058 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3059
3060 // Print out lock information
3061 if (JavaMonitorsInStackTrace) {
3062 jvf->print_lock_info_on(st, count);
3063 }
3064 } else {
3065 // Ignore non-Java frames
3066 }
3067
3068 // Bail-out case for too deep stacks
3069 count++;
3070 if (MaxJavaStackTraceDepth == count) return;
3071 }
3072 }
3073
3074
3075 // JVMTI PopFrame support
3076 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3077 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3078 if (in_bytes(size_in_bytes) != 0) {
3079 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3080 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3081 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3082 }
3083 }
3084
3085 void* JavaThread::popframe_preserved_args() {
3086 return _popframe_preserved_args;
3087 }
3088
3089 ByteSize JavaThread::popframe_preserved_args_size() {
3090 return in_ByteSize(_popframe_preserved_args_size);
3091 }
3092
3093 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3094 int sz = in_bytes(popframe_preserved_args_size());
3095 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3096 return in_WordSize(sz / wordSize);
3097 }
3098
3099 void JavaThread::popframe_free_preserved_args() {
3100 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3101 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3102 _popframe_preserved_args = NULL;
3103 _popframe_preserved_args_size = 0;
3104 }
3105
3106 #ifndef PRODUCT
3107
3108 void JavaThread::trace_frames() {
3109 tty->print_cr("[Describe stack]");
3110 int frame_no = 1;
3111 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3112 tty->print(" %d. ", frame_no++);
3113 fst.current()->print_value_on(tty,this);
3114 tty->cr();
3115 }
3116 }
3117
3118 class PrintAndVerifyOopClosure: public OopClosure {
3119 protected:
3120 template <class T> inline void do_oop_work(T* p) {
3121 oop obj = oopDesc::load_decode_heap_oop(p);
3122 if (obj == NULL) return;
3123 tty->print(INTPTR_FORMAT ": ", p);
3124 if (obj->is_oop_or_null()) {
3125 if (obj->is_objArray()) {
3126 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3127 } else {
3128 obj->print();
3129 }
3130 } else {
3131 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3132 }
3133 tty->cr();
3134 }
3135 public:
3136 virtual void do_oop(oop* p) { do_oop_work(p); }
3137 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3138 };
3139
3140
3141 static void oops_print(frame* f, const RegisterMap *map) {
3142 PrintAndVerifyOopClosure print;
3143 f->print_value();
3144 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3145 }
3146
3147 // Print our all the locations that contain oops and whether they are
3148 // valid or not. This useful when trying to find the oldest frame
3149 // where an oop has gone bad since the frame walk is from youngest to
3150 // oldest.
3151 void JavaThread::trace_oops() {
3152 tty->print_cr("[Trace oops]");
3153 frames_do(oops_print);
3154 }
3155
3156
3157 #ifdef ASSERT
3158 // Print or validate the layout of stack frames
3159 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3160 ResourceMark rm;
3161 PRESERVE_EXCEPTION_MARK;
3162 FrameValues values;
3163 int frame_no = 0;
3164 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3165 fst.current()->describe(values, ++frame_no);
3166 if (depth == frame_no) break;
3167 }
3168 if (validate_only) {
3169 values.validate();
3170 } else {
3171 tty->print_cr("[Describe stack layout]");
3172 values.print(this);
3173 }
3174 }
3175 #endif
3176
3177 void JavaThread::trace_stack_from(vframe* start_vf) {
3178 ResourceMark rm;
3179 int vframe_no = 1;
3180 for (vframe* f = start_vf; f; f = f->sender() ) {
3181 if (f->is_java_frame()) {
3182 javaVFrame::cast(f)->print_activation(vframe_no++);
3183 } else {
3184 f->print();
3185 }
3186 if (vframe_no > StackPrintLimit) {
3187 tty->print_cr("...<more frames>...");
3188 return;
3189 }
3190 }
3191 }
3192
3193
3194 void JavaThread::trace_stack() {
3195 if (!has_last_Java_frame()) return;
3196 ResourceMark rm;
3197 HandleMark hm;
3198 RegisterMap reg_map(this);
3199 trace_stack_from(last_java_vframe(®_map));
3200 }
3201
3202
3203 #endif // PRODUCT
3204
3205
3206 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3207 assert(reg_map != NULL, "a map must be given");
3208 frame f = last_frame();
3209 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3210 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3211 }
3212 return NULL;
3213 }
3214
3215
3216 Klass* JavaThread::security_get_caller_class(int depth) {
3217 vframeStream vfst(this);
3218 vfst.security_get_caller_frame(depth);
3219 if (!vfst.at_end()) {
3220 return vfst.method()->method_holder();
3221 }
3222 return NULL;
3223 }
3224
3225 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3226 assert(thread->is_Compiler_thread(), "must be compiler thread");
3227 CompileBroker::compiler_thread_loop();
3228 }
3229
3230 // Create a CompilerThread
3231 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3232 : JavaThread(&compiler_thread_entry) {
3233 _env = NULL;
3234 _log = NULL;
3235 _task = NULL;
3236 _queue = queue;
3237 _counters = counters;
3238 _buffer_blob = NULL;
3239 _scanned_nmethod = NULL;
3240
3241 #ifndef PRODUCT
3242 _ideal_graph_printer = NULL;
3243 #endif
3244 }
3245
3246 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
3247 JavaThread::oops_do(f, cld_f, cf);
3248 if (_scanned_nmethod != NULL && cf != NULL) {
3249 // Safepoints can occur when the sweeper is scanning an nmethod so
3250 // process it here to make sure it isn't unloaded in the middle of
3251 // a scan.
3252 cf->do_code_blob(_scanned_nmethod);
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 void os_stream();
3277
3278 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3279 void Threads::threads_do(ThreadClosure* tc) {
3280 assert_locked_or_safepoint(Threads_lock);
3281 // ALL_JAVA_THREADS iterates through all JavaThreads
3282 ALL_JAVA_THREADS(p) {
3283 tc->do_thread(p);
3284 }
3285 // Someday we could have a table or list of all non-JavaThreads.
3286 // For now, just manually iterate through them.
3287 tc->do_thread(VMThread::vm_thread());
3288 Universe::heap()->gc_threads_do(tc);
3289 WatcherThread *wt = WatcherThread::watcher_thread();
3290 // Strictly speaking, the following NULL check isn't sufficient to make sure
3291 // the data for WatcherThread is still valid upon being examined. However,
3292 // considering that WatchThread terminates when the VM is on the way to
3293 // exit at safepoint, the chance of the above is extremely small. The right
3294 // way to prevent termination of WatcherThread would be to acquire
3295 // Terminator_lock, but we can't do that without violating the lock rank
3296 // checking in some cases.
3297 if (wt != NULL)
3298 tc->do_thread(wt);
3299
3300 // If CompilerThreads ever become non-JavaThreads, add them here
3301 }
3302
3303 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3304
3305 extern void JDK_Version_init();
3306
3307 // Check version
3308 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3309
3310 // Initialize the output stream module
3311 ostream_init();
3312
3313 // Process java launcher properties.
3314 Arguments::process_sun_java_launcher_properties(args);
3315
3316 // Initialize the os module before using TLS
3317 os::init();
3318
3319 // Initialize system properties.
3320 Arguments::init_system_properties();
3321
3322 // So that JDK version can be used as a discrimintor when parsing arguments
3323 JDK_Version_init();
3324
3325 // Update/Initialize System properties after JDK version number is known
3326 Arguments::init_version_specific_system_properties();
3327
3328 // Parse arguments
3329 jint parse_result = Arguments::parse(args);
3330 if (parse_result != JNI_OK) return parse_result;
3331
3332 if (PauseAtStartup) {
3333 os::pause();
3334 }
3335
3336 #ifndef USDT2
3337 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3338 #else /* USDT2 */
3339 HOTSPOT_VM_INIT_BEGIN();
3340 #endif /* USDT2 */
3341
3342 // Record VM creation timing statistics
3343 TraceVmCreationTime create_vm_timer;
3344 create_vm_timer.start();
3345
3346 // Timing (must come after argument parsing)
3347 TraceTime timer("Create VM", TraceStartupTime);
3348
3349 // Initialize the os module after parsing the args
3350 jint os_init_2_result = os::init_2();
3351 if (os_init_2_result != JNI_OK) return os_init_2_result;
3352
3353 jint adjust_after_os_result = Arguments::adjust_after_os();
3354 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3355
3356 // intialize TLS
3357 ThreadLocalStorage::init();
3358
3359 // Bootstrap native memory tracking, so it can start recording memory
3360 // activities before worker thread is started. This is the first phase
3361 // of bootstrapping, VM is currently running in single-thread mode.
3362 MemTracker::bootstrap_single_thread();
3363
3364 // Initialize output stream logging
3365 ostream_init_log();
3366
3367 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3368 // Must be before create_vm_init_agents()
3369 if (Arguments::init_libraries_at_startup()) {
3370 convert_vm_init_libraries_to_agents();
3371 }
3372
3373 // Launch -agentlib/-agentpath and converted -Xrun agents
3374 if (Arguments::init_agents_at_startup()) {
3375 create_vm_init_agents();
3376 }
3377
3378 // Initialize Threads state
3379 _thread_list = NULL;
3380 _number_of_threads = 0;
3381 _number_of_non_daemon_threads = 0;
3382
3383 // Initialize global data structures and create system classes in heap
3384 vm_init_globals();
3385
3386 // Attach the main thread to this os thread
3387 JavaThread* main_thread = new JavaThread();
3388 main_thread->set_thread_state(_thread_in_vm);
3389 // must do this before set_active_handles and initialize_thread_local_storage
3390 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3391 // change the stack size recorded here to one based on the java thread
3392 // stacksize. This adjusted size is what is used to figure the placement
3393 // of the guard pages.
3394 main_thread->record_stack_base_and_size();
3395 main_thread->initialize_thread_local_storage();
3396
3397 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3398
3399 if (!main_thread->set_as_starting_thread()) {
3400 vm_shutdown_during_initialization(
3401 "Failed necessary internal allocation. Out of swap space");
3402 delete main_thread;
3403 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3404 return JNI_ENOMEM;
3405 }
3406
3407 // Enable guard page *after* os::create_main_thread(), otherwise it would
3408 // crash Linux VM, see notes in os_linux.cpp.
3409 main_thread->create_stack_guard_pages();
3410
3411 // Initialize Java-Level synchronization subsystem
3412 ObjectMonitor::Initialize() ;
3413
3414 // Second phase of bootstrapping, VM is about entering multi-thread mode
3415 MemTracker::bootstrap_multi_thread();
3416
3417 // Initialize global modules
3418 jint status = init_globals();
3419 if (status != JNI_OK) {
3420 delete main_thread;
3421 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3422 return status;
3423 }
3424
3425 // Should be done after the heap is fully created
3426 main_thread->cache_global_variables();
3427
3428 HandleMark hm;
3429
3430 { MutexLocker mu(Threads_lock);
3431 Threads::add(main_thread);
3432 }
3433
3434 // Any JVMTI raw monitors entered in onload will transition into
3435 // real raw monitor. VM is setup enough here for raw monitor enter.
3436 JvmtiExport::transition_pending_onload_raw_monitors();
3437
3438 // Fully start NMT
3439 MemTracker::start();
3440
3441 // Create the VMThread
3442 { TraceTime timer("Start VMThread", TraceStartupTime);
3443 VMThread::create();
3444 Thread* vmthread = VMThread::vm_thread();
3445
3446 if (!os::create_thread(vmthread, os::vm_thread))
3447 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3448
3449 // Wait for the VM thread to become ready, and VMThread::run to initialize
3450 // Monitors can have spurious returns, must always check another state flag
3451 {
3452 MutexLocker ml(Notify_lock);
3453 os::start_thread(vmthread);
3454 while (vmthread->active_handles() == NULL) {
3455 Notify_lock->wait();
3456 }
3457 }
3458 }
3459
3460 assert (Universe::is_fully_initialized(), "not initialized");
3461 if (VerifyDuringStartup) {
3462 // Make sure we're starting with a clean slate.
3463 VM_Verify verify_op;
3464 VMThread::execute(&verify_op);
3465 }
3466
3467 EXCEPTION_MARK;
3468
3469 // At this point, the Universe is initialized, but we have not executed
3470 // any byte code. Now is a good time (the only time) to dump out the
3471 // internal state of the JVM for sharing.
3472 if (DumpSharedSpaces) {
3473 MetaspaceShared::preload_and_dump(CHECK_0);
3474 ShouldNotReachHere();
3475 }
3476
3477 // Always call even when there are not JVMTI environments yet, since environments
3478 // may be attached late and JVMTI must track phases of VM execution
3479 JvmtiExport::enter_start_phase();
3480
3481 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3482 JvmtiExport::post_vm_start();
3483
3484 {
3485 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3486
3487 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3488 create_vm_init_libraries();
3489 }
3490
3491 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3492
3493 // Initialize java_lang.System (needed before creating the thread)
3494 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3495 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3496 Handle thread_group = create_initial_thread_group(CHECK_0);
3497 Universe::set_main_thread_group(thread_group());
3498 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3499 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3500 main_thread->set_threadObj(thread_object);
3501 // Set thread status to running since main thread has
3502 // been started and running.
3503 java_lang_Thread::set_thread_status(thread_object,
3504 java_lang_Thread::RUNNABLE);
3505
3506 // The VM creates & returns objects of this class. Make sure it's initialized.
3507 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3508
3509 // The VM preresolves methods to these classes. Make sure that they get initialized
3510 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3511 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3512 call_initializeSystemClass(CHECK_0);
3513
3514 // get the Java runtime name after java.lang.System is initialized
3515 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3516 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3517
3518 // an instance of OutOfMemory exception has been allocated earlier
3519 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3520 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3521 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3522 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3523 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3524 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3525 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3526 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3527 }
3528
3529 // See : bugid 4211085.
3530 // Background : the static initializer of java.lang.Compiler tries to read
3531 // property"java.compiler" and read & write property "java.vm.info".
3532 // When a security manager is installed through the command line
3533 // option "-Djava.security.manager", the above properties are not
3534 // readable and the static initializer for java.lang.Compiler fails
3535 // resulting in a NoClassDefFoundError. This can happen in any
3536 // user code which calls methods in java.lang.Compiler.
3537 // Hack : the hack is to pre-load and initialize this class, so that only
3538 // system domains are on the stack when the properties are read.
3539 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3540 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3541 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3542 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3543 // Once that is done, we should remove this hack.
3544 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3545
3546 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3547 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3548 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3549 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3550 // This should also be taken out as soon as 4211383 gets fixed.
3551 reset_vm_info_property(CHECK_0);
3552
3553 quicken_jni_functions();
3554
3555 // Must be run after init_ft which initializes ft_enabled
3556 if (TRACE_INITIALIZE() != JNI_OK) {
3557 vm_exit_during_initialization("Failed to initialize tracing backend");
3558 }
3559
3560 // Set flag that basic initialization has completed. Used by exceptions and various
3561 // debug stuff, that does not work until all basic classes have been initialized.
3562 set_init_completed();
3563
3564 #ifndef USDT2
3565 HS_DTRACE_PROBE(hotspot, vm__init__end);
3566 #else /* USDT2 */
3567 HOTSPOT_VM_INIT_END();
3568 #endif /* USDT2 */
3569
3570 // record VM initialization completion time
3571 #if INCLUDE_MANAGEMENT
3572 Management::record_vm_init_completed();
3573 #endif // INCLUDE_MANAGEMENT
3574
3575 // Compute system loader. Note that this has to occur after set_init_completed, since
3576 // valid exceptions may be thrown in the process.
3577 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3578 // set_init_completed has just been called, causing exceptions not to be shortcut
3579 // anymore. We call vm_exit_during_initialization directly instead.
3580 SystemDictionary::compute_java_system_loader(THREAD);
3581 if (HAS_PENDING_EXCEPTION) {
3582 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3583 }
3584
3585 #if INCLUDE_ALL_GCS
3586 // Support for ConcurrentMarkSweep. This should be cleaned up
3587 // and better encapsulated. The ugly nested if test would go away
3588 // once things are properly refactored. XXX YSR
3589 if (UseConcMarkSweepGC || UseG1GC) {
3590 if (UseConcMarkSweepGC) {
3591 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3592 } else {
3593 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3594 }
3595 if (HAS_PENDING_EXCEPTION) {
3596 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3597 }
3598 }
3599 #endif // INCLUDE_ALL_GCS
3600
3601 // Always call even when there are not JVMTI environments yet, since environments
3602 // may be attached late and JVMTI must track phases of VM execution
3603 JvmtiExport::enter_live_phase();
3604
3605 // Signal Dispatcher needs to be started before VMInit event is posted
3606 os::signal_init();
3607
3608 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3609 if (!DisableAttachMechanism) {
3610 AttachListener::vm_start();
3611 if (StartAttachListener || AttachListener::init_at_startup()) {
3612 AttachListener::init();
3613 }
3614 }
3615
3616 // Launch -Xrun agents
3617 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3618 // back-end can launch with -Xdebug -Xrunjdwp.
3619 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3620 create_vm_init_libraries();
3621 }
3622
3623 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3624 JvmtiExport::post_vm_initialized();
3625
3626 if (TRACE_START() != JNI_OK) {
3627 vm_exit_during_initialization("Failed to start tracing backend.");
3628 }
3629
3630 if (CleanChunkPoolAsync) {
3631 Chunk::start_chunk_pool_cleaner_task();
3632 }
3633
3634 // initialize compiler(s)
3635 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3636 CompileBroker::compilation_init();
3637 #endif
3638
3639 #if INCLUDE_MANAGEMENT
3640 Management::initialize(THREAD);
3641 #endif // INCLUDE_MANAGEMENT
3642
3643 if (HAS_PENDING_EXCEPTION) {
3644 // management agent fails to start possibly due to
3645 // configuration problem and is responsible for printing
3646 // stack trace if appropriate. Simply exit VM.
3647 vm_exit(1);
3648 }
3649
3650 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3651 if (MemProfiling) MemProfiler::engage();
3652 StatSampler::engage();
3653 if (CheckJNICalls) JniPeriodicChecker::engage();
3654
3655 BiasedLocking::init();
3656
3657 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3658 call_postVMInitHook(THREAD);
3659 // The Java side of PostVMInitHook.run must deal with all
3660 // exceptions and provide means of diagnosis.
3661 if (HAS_PENDING_EXCEPTION) {
3662 CLEAR_PENDING_EXCEPTION;
3663 }
3664 }
3665
3666 {
3667 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3668 // Make sure the watcher thread can be started by WatcherThread::start()
3669 // or by dynamic enrollment.
3670 WatcherThread::make_startable();
3671 // Start up the WatcherThread if there are any periodic tasks
3672 // NOTE: All PeriodicTasks should be registered by now. If they
3673 // aren't, late joiners might appear to start slowly (we might
3674 // take a while to process their first tick).
3675 if (PeriodicTask::num_tasks() > 0) {
3676 WatcherThread::start();
3677 }
3678 }
3679
3680 // Give os specific code one last chance to start
3681 os::init_3();
3682
3683 create_vm_timer.end();
3684 #ifdef ASSERT
3685 _vm_complete = true;
3686 #endif
3687 return JNI_OK;
3688 }
3689
3690 // type for the Agent_OnLoad and JVM_OnLoad entry points
3691 extern "C" {
3692 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3693 }
3694 // Find a command line agent library and return its entry point for
3695 // -agentlib: -agentpath: -Xrun
3696 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3697 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3698 OnLoadEntry_t on_load_entry = NULL;
3699 void *library;
3700
3701 if (!agent->valid()) {
3702 char buffer[JVM_MAXPATHLEN];
3703 char ebuf[1024];
3704 const char *name = agent->name();
3705 const char *msg = "Could not find agent library ";
3706
3707 // First check to see if agent is statcally linked into executable
3708 if (os::findBuiltinAgent(agent, on_load_symbols, num_symbol_entries)) {
3709 library = agent->os_lib();
3710 } else if (agent->is_absolute_path()) {
3711 library = os::dll_load(name, ebuf, sizeof ebuf);
3712 if (library == NULL) {
3713 const char *sub_msg = " in absolute path, with error: ";
3714 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3715 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3716 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3717 // If we can't find the agent, exit.
3718 vm_exit_during_initialization(buf, NULL);
3719 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3720 }
3721 } else {
3722 // Try to load the agent from the standard dll directory
3723 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3724 name)) {
3725 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3726 }
3727 if (library == NULL) { // Try the local directory
3728 char ns[1] = {0};
3729 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3730 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3731 }
3732 if (library == NULL) {
3733 const char *sub_msg = " on the library path, with error: ";
3734 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3735 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3736 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3737 // If we can't find the agent, exit.
3738 vm_exit_during_initialization(buf, NULL);
3739 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3740 }
3741 }
3742 }
3743 agent->set_os_lib(library);
3744 agent->set_valid();
3745 }
3746
3747 // Find the OnLoad function.
3748 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::findAgentFunction(agent,
3749 false,
3750 on_load_symbols,
3751 num_symbol_entries));
3752 return on_load_entry;
3753 }
3754
3755 // Find the JVM_OnLoad entry point
3756 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3757 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3758 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3759 }
3760
3761 // Find the Agent_OnLoad entry point
3762 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3763 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3764 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3765 }
3766
3767 // For backwards compatibility with -Xrun
3768 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3769 // treated like -agentpath:
3770 // Must be called before agent libraries are created
3771 void Threads::convert_vm_init_libraries_to_agents() {
3772 AgentLibrary* agent;
3773 AgentLibrary* next;
3774
3775 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3776 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3777 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3778
3779 // If there is an JVM_OnLoad function it will get called later,
3780 // otherwise see if there is an Agent_OnLoad
3781 if (on_load_entry == NULL) {
3782 on_load_entry = lookup_agent_on_load(agent);
3783 if (on_load_entry != NULL) {
3784 // switch it to the agent list -- so that Agent_OnLoad will be called,
3785 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3786 Arguments::convert_library_to_agent(agent);
3787 } else {
3788 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3789 }
3790 }
3791 }
3792 }
3793
3794 // Create agents for -agentlib: -agentpath: and converted -Xrun
3795 // Invokes Agent_OnLoad
3796 // Called very early -- before JavaThreads exist
3797 void Threads::create_vm_init_agents() {
3798 extern struct JavaVM_ main_vm;
3799 AgentLibrary* agent;
3800
3801 JvmtiExport::enter_onload_phase();
3802
3803 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3804 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3805
3806 if (on_load_entry != NULL) {
3807 // Invoke the Agent_OnLoad function
3808 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3809 if (err != JNI_OK) {
3810 vm_exit_during_initialization("agent library failed to init", agent->name());
3811 }
3812 } else {
3813 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3814 }
3815 }
3816 JvmtiExport::enter_primordial_phase();
3817 }
3818
3819 extern "C" {
3820 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3821 }
3822
3823 void Threads::shutdown_vm_agents() {
3824 // Send any Agent_OnUnload notifications
3825 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3826 size_t num_symbol_entries = sizeof(on_unload_symbols) / sizeof(char*);
3827 extern struct JavaVM_ main_vm;
3828 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3829
3830 // Find the Agent_OnUnload function.
3831 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3832 os::findAgentFunction(agent,
3833 false,
3834 on_unload_symbols,
3835 num_symbol_entries));
3836
3837 // Invoke the Agent_OnUnload function
3838 if (unload_entry != NULL) {
3839 JavaThread* thread = JavaThread::current();
3840 ThreadToNativeFromVM ttn(thread);
3841 HandleMark hm(thread);
3842 (*unload_entry)(&main_vm);
3843 }
3844 }
3845 }
3846
3847 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3848 // Invokes JVM_OnLoad
3849 void Threads::create_vm_init_libraries() {
3850 extern struct JavaVM_ main_vm;
3851 AgentLibrary* agent;
3852
3853 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3854 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3855
3856 if (on_load_entry != NULL) {
3857 // Invoke the JVM_OnLoad function
3858 JavaThread* thread = JavaThread::current();
3859 ThreadToNativeFromVM ttn(thread);
3860 HandleMark hm(thread);
3861 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3862 if (err != JNI_OK) {
3863 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3864 }
3865 } else {
3866 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3867 }
3868 }
3869 }
3870
3871 // Last thread running calls java.lang.Shutdown.shutdown()
3872 void JavaThread::invoke_shutdown_hooks() {
3873 HandleMark hm(this);
3874
3875 // We could get here with a pending exception, if so clear it now.
3876 if (this->has_pending_exception()) {
3877 this->clear_pending_exception();
3878 }
3879
3880 EXCEPTION_MARK;
3881 Klass* k =
3882 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3883 THREAD);
3884 if (k != NULL) {
3885 // SystemDictionary::resolve_or_null will return null if there was
3886 // an exception. If we cannot load the Shutdown class, just don't
3887 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3888 // and finalizers (if runFinalizersOnExit is set) won't be run.
3889 // Note that if a shutdown hook was registered or runFinalizersOnExit
3890 // was called, the Shutdown class would have already been loaded
3891 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3892 instanceKlassHandle shutdown_klass (THREAD, k);
3893 JavaValue result(T_VOID);
3894 JavaCalls::call_static(&result,
3895 shutdown_klass,
3896 vmSymbols::shutdown_method_name(),
3897 vmSymbols::void_method_signature(),
3898 THREAD);
3899 }
3900 CLEAR_PENDING_EXCEPTION;
3901 }
3902
3903 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3904 // the program falls off the end of main(). Another VM exit path is through
3905 // vm_exit() when the program calls System.exit() to return a value or when
3906 // there is a serious error in VM. The two shutdown paths are not exactly
3907 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3908 // and VM_Exit op at VM level.
3909 //
3910 // Shutdown sequence:
3911 // + Shutdown native memory tracking if it is on
3912 // + Wait until we are the last non-daemon thread to execute
3913 // <-- every thing is still working at this moment -->
3914 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3915 // shutdown hooks, run finalizers if finalization-on-exit
3916 // + Call before_exit(), prepare for VM exit
3917 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3918 // currently the only user of this mechanism is File.deleteOnExit())
3919 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3920 // post thread end and vm death events to JVMTI,
3921 // stop signal thread
3922 // + Call JavaThread::exit(), it will:
3923 // > release JNI handle blocks, remove stack guard pages
3924 // > remove this thread from Threads list
3925 // <-- no more Java code from this thread after this point -->
3926 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3927 // the compiler threads at safepoint
3928 // <-- do not use anything that could get blocked by Safepoint -->
3929 // + Disable tracing at JNI/JVM barriers
3930 // + Set _vm_exited flag for threads that are still running native code
3931 // + Delete this thread
3932 // + Call exit_globals()
3933 // > deletes tty
3934 // > deletes PerfMemory resources
3935 // + Return to caller
3936
3937 bool Threads::destroy_vm() {
3938 JavaThread* thread = JavaThread::current();
3939
3940 #ifdef ASSERT
3941 _vm_complete = false;
3942 #endif
3943 // Wait until we are the last non-daemon thread to execute
3944 { MutexLocker nu(Threads_lock);
3945 while (Threads::number_of_non_daemon_threads() > 1 )
3946 // This wait should make safepoint checks, wait without a timeout,
3947 // and wait as a suspend-equivalent condition.
3948 //
3949 // Note: If the FlatProfiler is running and this thread is waiting
3950 // for another non-daemon thread to finish, then the FlatProfiler
3951 // is waiting for the external suspend request on this thread to
3952 // complete. wait_for_ext_suspend_completion() will eventually
3953 // timeout, but that takes time. Making this wait a suspend-
3954 // equivalent condition solves that timeout problem.
3955 //
3956 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3957 Mutex::_as_suspend_equivalent_flag);
3958 }
3959
3960 // Hang forever on exit if we are reporting an error.
3961 if (ShowMessageBoxOnError && is_error_reported()) {
3962 os::infinite_sleep();
3963 }
3964 os::wait_for_keypress_at_exit();
3965
3966 if (JDK_Version::is_jdk12x_version()) {
3967 // We are the last thread running, so check if finalizers should be run.
3968 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3969 HandleMark rm(thread);
3970 Universe::run_finalizers_on_exit();
3971 } else {
3972 // run Java level shutdown hooks
3973 thread->invoke_shutdown_hooks();
3974 }
3975
3976 before_exit(thread);
3977
3978 thread->exit(true);
3979
3980 // Stop VM thread.
3981 {
3982 // 4945125 The vm thread comes to a safepoint during exit.
3983 // GC vm_operations can get caught at the safepoint, and the
3984 // heap is unparseable if they are caught. Grab the Heap_lock
3985 // to prevent this. The GC vm_operations will not be able to
3986 // queue until after the vm thread is dead.
3987 // After this point, we'll never emerge out of the safepoint before
3988 // the VM exits, so concurrent GC threads do not need to be explicitly
3989 // stopped; they remain inactive until the process exits.
3990 // Note: some concurrent G1 threads may be running during a safepoint,
3991 // but these will not be accessing the heap, just some G1-specific side
3992 // data structures that are not accessed by any other threads but them
3993 // after this point in a terminal safepoint.
3994
3995 MutexLocker ml(Heap_lock);
3996
3997 VMThread::wait_for_vm_thread_exit();
3998 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3999 VMThread::destroy();
4000 }
4001
4002 // clean up ideal graph printers
4003 #if defined(COMPILER2) && !defined(PRODUCT)
4004 IdealGraphPrinter::clean_up();
4005 #endif
4006
4007 // Now, all Java threads are gone except daemon threads. Daemon threads
4008 // running Java code or in VM are stopped by the Safepoint. However,
4009 // daemon threads executing native code are still running. But they
4010 // will be stopped at native=>Java/VM barriers. Note that we can't
4011 // simply kill or suspend them, as it is inherently deadlock-prone.
4012
4013 #ifndef PRODUCT
4014 // disable function tracing at JNI/JVM barriers
4015 TraceJNICalls = false;
4016 TraceJVMCalls = false;
4017 TraceRuntimeCalls = false;
4018 #endif
4019
4020 VM_Exit::set_vm_exited();
4021
4022 notify_vm_shutdown();
4023
4024 delete thread;
4025
4026 // exit_globals() will delete tty
4027 exit_globals();
4028
4029 return true;
4030 }
4031
4032
4033 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4034 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4035 return is_supported_jni_version(version);
4036 }
4037
4038
4039 jboolean Threads::is_supported_jni_version(jint version) {
4040 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4041 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4042 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4043 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4044 return JNI_FALSE;
4045 }
4046
4047
4048 void Threads::add(JavaThread* p, bool force_daemon) {
4049 // The threads lock must be owned at this point
4050 assert_locked_or_safepoint(Threads_lock);
4051
4052 // See the comment for this method in thread.hpp for its purpose and
4053 // why it is called here.
4054 p->initialize_queues();
4055 p->set_next(_thread_list);
4056 _thread_list = p;
4057 _number_of_threads++;
4058 oop threadObj = p->threadObj();
4059 bool daemon = true;
4060 // Bootstrapping problem: threadObj can be null for initial
4061 // JavaThread (or for threads attached via JNI)
4062 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4063 _number_of_non_daemon_threads++;
4064 daemon = false;
4065 }
4066
4067 p->set_safepoint_visible(true);
4068
4069 ThreadService::add_thread(p, daemon);
4070
4071 // Possible GC point.
4072 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4073 }
4074
4075 void Threads::remove(JavaThread* p) {
4076 // Extra scope needed for Thread_lock, so we can check
4077 // that we do not remove thread without safepoint code notice
4078 { MutexLocker ml(Threads_lock);
4079
4080 assert(includes(p), "p must be present");
4081
4082 JavaThread* current = _thread_list;
4083 JavaThread* prev = NULL;
4084
4085 while (current != p) {
4086 prev = current;
4087 current = current->next();
4088 }
4089
4090 if (prev) {
4091 prev->set_next(current->next());
4092 } else {
4093 _thread_list = p->next();
4094 }
4095 _number_of_threads--;
4096 oop threadObj = p->threadObj();
4097 bool daemon = true;
4098 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4099 _number_of_non_daemon_threads--;
4100 daemon = false;
4101
4102 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4103 // on destroy_vm will wake up.
4104 if (number_of_non_daemon_threads() == 1)
4105 Threads_lock->notify_all();
4106 }
4107 ThreadService::remove_thread(p, daemon);
4108
4109 // Make sure that safepoint code disregard this thread. This is needed since
4110 // the thread might mess around with locks after this point. This can cause it
4111 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4112 // of this thread since it is removed from the queue.
4113 p->set_terminated_value();
4114
4115 // Now, this thread is not visible to safepoint
4116 p->set_safepoint_visible(false);
4117 // once the thread becomes safepoint invisible, we can not use its per-thread
4118 // recorder. And Threads::do_threads() no longer walks this thread, so we have
4119 // to release its per-thread recorder here.
4120 MemTracker::thread_exiting(p);
4121 } // unlock Threads_lock
4122
4123 // Since Events::log uses a lock, we grab it outside the Threads_lock
4124 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4125 }
4126
4127 // Threads_lock must be held when this is called (or must be called during a safepoint)
4128 bool Threads::includes(JavaThread* p) {
4129 assert(Threads_lock->is_locked(), "sanity check");
4130 ALL_JAVA_THREADS(q) {
4131 if (q == p ) {
4132 return true;
4133 }
4134 }
4135 return false;
4136 }
4137
4138 // Operations on the Threads list for GC. These are not explicitly locked,
4139 // but the garbage collector must provide a safe context for them to run.
4140 // In particular, these things should never be called when the Threads_lock
4141 // is held by some other thread. (Note: the Safepoint abstraction also
4142 // uses the Threads_lock to gurantee this property. It also makes sure that
4143 // all threads gets blocked when exiting or starting).
4144
4145 void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4146 ALL_JAVA_THREADS(p) {
4147 p->oops_do(f, cld_f, cf);
4148 }
4149 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4150 }
4151
4152 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4153 // Introduce a mechanism allowing parallel threads to claim threads as
4154 // root groups. Overhead should be small enough to use all the time,
4155 // even in sequential code.
4156 SharedHeap* sh = SharedHeap::heap();
4157 // Cannot yet substitute active_workers for n_par_threads
4158 // because of G1CollectedHeap::verify() use of
4159 // SharedHeap::process_strong_roots(). n_par_threads == 0 will
4160 // turn off parallelism in process_strong_roots while active_workers
4161 // is being used for parallelism elsewhere.
4162 bool is_par = sh->n_par_threads() > 0;
4163 assert(!is_par ||
4164 (SharedHeap::heap()->n_par_threads() ==
4165 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4166 int cp = SharedHeap::heap()->strong_roots_parity();
4167 ALL_JAVA_THREADS(p) {
4168 if (p->claim_oops_do(is_par, cp)) {
4169 p->oops_do(f, cld_f, cf);
4170 }
4171 }
4172 VMThread* vmt = VMThread::vm_thread();
4173 if (vmt->claim_oops_do(is_par, cp)) {
4174 vmt->oops_do(f, cld_f, cf);
4175 }
4176 }
4177
4178 #if INCLUDE_ALL_GCS
4179 // Used by ParallelScavenge
4180 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4181 ALL_JAVA_THREADS(p) {
4182 q->enqueue(new ThreadRootsTask(p));
4183 }
4184 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4185 }
4186
4187 // Used by Parallel Old
4188 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4189 ALL_JAVA_THREADS(p) {
4190 q->enqueue(new ThreadRootsMarkingTask(p));
4191 }
4192 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4193 }
4194 #endif // INCLUDE_ALL_GCS
4195
4196 void Threads::nmethods_do(CodeBlobClosure* cf) {
4197 ALL_JAVA_THREADS(p) {
4198 p->nmethods_do(cf);
4199 }
4200 VMThread::vm_thread()->nmethods_do(cf);
4201 }
4202
4203 void Threads::metadata_do(void f(Metadata*)) {
4204 ALL_JAVA_THREADS(p) {
4205 p->metadata_do(f);
4206 }
4207 }
4208
4209 void Threads::gc_epilogue() {
4210 ALL_JAVA_THREADS(p) {
4211 p->gc_epilogue();
4212 }
4213 }
4214
4215 void Threads::gc_prologue() {
4216 ALL_JAVA_THREADS(p) {
4217 p->gc_prologue();
4218 }
4219 }
4220
4221 void Threads::deoptimized_wrt_marked_nmethods() {
4222 ALL_JAVA_THREADS(p) {
4223 p->deoptimized_wrt_marked_nmethods();
4224 }
4225 }
4226
4227
4228 // Get count Java threads that are waiting to enter the specified monitor.
4229 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4230 address monitor, bool doLock) {
4231 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4232 "must grab Threads_lock or be at safepoint");
4233 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4234
4235 int i = 0;
4236 {
4237 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4238 ALL_JAVA_THREADS(p) {
4239 if (p->is_Compiler_thread()) continue;
4240
4241 address pending = (address)p->current_pending_monitor();
4242 if (pending == monitor) { // found a match
4243 if (i < count) result->append(p); // save the first count matches
4244 i++;
4245 }
4246 }
4247 }
4248 return result;
4249 }
4250
4251
4252 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4253 assert(doLock ||
4254 Threads_lock->owned_by_self() ||
4255 SafepointSynchronize::is_at_safepoint(),
4256 "must grab Threads_lock or be at safepoint");
4257
4258 // NULL owner means not locked so we can skip the search
4259 if (owner == NULL) return NULL;
4260
4261 {
4262 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4263 ALL_JAVA_THREADS(p) {
4264 // first, see if owner is the address of a Java thread
4265 if (owner == (address)p) return p;
4266 }
4267 }
4268 // Cannot assert on lack of success here since this function may be
4269 // used by code that is trying to report useful problem information
4270 // like deadlock detection.
4271 if (UseHeavyMonitors) return NULL;
4272
4273 //
4274 // If we didn't find a matching Java thread and we didn't force use of
4275 // heavyweight monitors, then the owner is the stack address of the
4276 // Lock Word in the owning Java thread's stack.
4277 //
4278 JavaThread* the_owner = NULL;
4279 {
4280 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4281 ALL_JAVA_THREADS(q) {
4282 if (q->is_lock_owned(owner)) {
4283 the_owner = q;
4284 break;
4285 }
4286 }
4287 }
4288 // cannot assert on lack of success here; see above comment
4289 return the_owner;
4290 }
4291
4292 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4293 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4294 char buf[32];
4295 st->print_cr(os::local_time_string(buf, sizeof(buf)));
4296
4297 st->print_cr("Full thread dump %s (%s %s):",
4298 Abstract_VM_Version::vm_name(),
4299 Abstract_VM_Version::vm_release(),
4300 Abstract_VM_Version::vm_info_string()
4301 );
4302 st->cr();
4303
4304 #if INCLUDE_ALL_GCS
4305 // Dump concurrent locks
4306 ConcurrentLocksDump concurrent_locks;
4307 if (print_concurrent_locks) {
4308 concurrent_locks.dump_at_safepoint();
4309 }
4310 #endif // INCLUDE_ALL_GCS
4311
4312 ALL_JAVA_THREADS(p) {
4313 ResourceMark rm;
4314 p->print_on(st);
4315 if (print_stacks) {
4316 if (internal_format) {
4317 p->trace_stack();
4318 } else {
4319 p->print_stack_on(st);
4320 }
4321 }
4322 st->cr();
4323 #if INCLUDE_ALL_GCS
4324 if (print_concurrent_locks) {
4325 concurrent_locks.print_locks_on(p, st);
4326 }
4327 #endif // INCLUDE_ALL_GCS
4328 }
4329
4330 VMThread::vm_thread()->print_on(st);
4331 st->cr();
4332 Universe::heap()->print_gc_threads_on(st);
4333 WatcherThread* wt = WatcherThread::watcher_thread();
4334 if (wt != NULL) {
4335 wt->print_on(st);
4336 st->cr();
4337 }
4338 CompileBroker::print_compiler_threads_on(st);
4339 st->flush();
4340 }
4341
4342 // Threads::print_on_error() is called by fatal error handler. It's possible
4343 // that VM is not at safepoint and/or current thread is inside signal handler.
4344 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4345 // memory (even in resource area), it might deadlock the error handler.
4346 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4347 bool found_current = false;
4348 st->print_cr("Java Threads: ( => current thread )");
4349 ALL_JAVA_THREADS(thread) {
4350 bool is_current = (current == thread);
4351 found_current = found_current || is_current;
4352
4353 st->print("%s", is_current ? "=>" : " ");
4354
4355 st->print(PTR_FORMAT, thread);
4356 st->print(" ");
4357 thread->print_on_error(st, buf, buflen);
4358 st->cr();
4359 }
4360 st->cr();
4361
4362 st->print_cr("Other Threads:");
4363 if (VMThread::vm_thread()) {
4364 bool is_current = (current == VMThread::vm_thread());
4365 found_current = found_current || is_current;
4366 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4367
4368 st->print(PTR_FORMAT, VMThread::vm_thread());
4369 st->print(" ");
4370 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4371 st->cr();
4372 }
4373 WatcherThread* wt = WatcherThread::watcher_thread();
4374 if (wt != NULL) {
4375 bool is_current = (current == wt);
4376 found_current = found_current || is_current;
4377 st->print("%s", is_current ? "=>" : " ");
4378
4379 st->print(PTR_FORMAT, wt);
4380 st->print(" ");
4381 wt->print_on_error(st, buf, buflen);
4382 st->cr();
4383 }
4384 if (!found_current) {
4385 st->cr();
4386 st->print("=>" PTR_FORMAT " (exited) ", current);
4387 current->print_on_error(st, buf, buflen);
4388 st->cr();
4389 }
4390 }
4391
4392 // Internal SpinLock and Mutex
4393 // Based on ParkEvent
4394
4395 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4396 //
4397 // We employ SpinLocks _only for low-contention, fixed-length
4398 // short-duration critical sections where we're concerned
4399 // about native mutex_t or HotSpot Mutex:: latency.
4400 // The mux construct provides a spin-then-block mutual exclusion
4401 // mechanism.
4402 //
4403 // Testing has shown that contention on the ListLock guarding gFreeList
4404 // is common. If we implement ListLock as a simple SpinLock it's common
4405 // for the JVM to devolve to yielding with little progress. This is true
4406 // despite the fact that the critical sections protected by ListLock are
4407 // extremely short.
4408 //
4409 // TODO-FIXME: ListLock should be of type SpinLock.
4410 // We should make this a 1st-class type, integrated into the lock
4411 // hierarchy as leaf-locks. Critically, the SpinLock structure
4412 // should have sufficient padding to avoid false-sharing and excessive
4413 // cache-coherency traffic.
4414
4415
4416 typedef volatile int SpinLockT ;
4417
4418 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4419 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4420 return ; // normal fast-path return
4421 }
4422
4423 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4424 TEVENT (SpinAcquire - ctx) ;
4425 int ctr = 0 ;
4426 int Yields = 0 ;
4427 for (;;) {
4428 while (*adr != 0) {
4429 ++ctr ;
4430 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4431 if (Yields > 5) {
4432 // Consider using a simple NakedSleep() instead.
4433 // Then SpinAcquire could be called by non-JVM threads
4434 Thread::current()->_ParkEvent->park(1) ;
4435 } else {
4436 os::NakedYield() ;
4437 ++Yields ;
4438 }
4439 } else {
4440 SpinPause() ;
4441 }
4442 }
4443 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4444 }
4445 }
4446
4447 void Thread::SpinRelease (volatile int * adr) {
4448 assert (*adr != 0, "invariant") ;
4449 OrderAccess::fence() ; // guarantee at least release consistency.
4450 // Roach-motel semantics.
4451 // It's safe if subsequent LDs and STs float "up" into the critical section,
4452 // but prior LDs and STs within the critical section can't be allowed
4453 // to reorder or float past the ST that releases the lock.
4454 *adr = 0 ;
4455 }
4456
4457 // muxAcquire and muxRelease:
4458 //
4459 // * muxAcquire and muxRelease support a single-word lock-word construct.
4460 // The LSB of the word is set IFF the lock is held.
4461 // The remainder of the word points to the head of a singly-linked list
4462 // of threads blocked on the lock.
4463 //
4464 // * The current implementation of muxAcquire-muxRelease uses its own
4465 // dedicated Thread._MuxEvent instance. If we're interested in
4466 // minimizing the peak number of extant ParkEvent instances then
4467 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4468 // as certain invariants were satisfied. Specifically, care would need
4469 // to be taken with regards to consuming unpark() "permits".
4470 // A safe rule of thumb is that a thread would never call muxAcquire()
4471 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4472 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4473 // consume an unpark() permit intended for monitorenter, for instance.
4474 // One way around this would be to widen the restricted-range semaphore
4475 // implemented in park(). Another alternative would be to provide
4476 // multiple instances of the PlatformEvent() for each thread. One
4477 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4478 //
4479 // * Usage:
4480 // -- Only as leaf locks
4481 // -- for short-term locking only as muxAcquire does not perform
4482 // thread state transitions.
4483 //
4484 // Alternatives:
4485 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4486 // but with parking or spin-then-park instead of pure spinning.
4487 // * Use Taura-Oyama-Yonenzawa locks.
4488 // * It's possible to construct a 1-0 lock if we encode the lockword as
4489 // (List,LockByte). Acquire will CAS the full lockword while Release
4490 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4491 // acquiring threads use timers (ParkTimed) to detect and recover from
4492 // the stranding window. Thread/Node structures must be aligned on 256-byte
4493 // boundaries by using placement-new.
4494 // * Augment MCS with advisory back-link fields maintained with CAS().
4495 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4496 // The validity of the backlinks must be ratified before we trust the value.
4497 // If the backlinks are invalid the exiting thread must back-track through the
4498 // the forward links, which are always trustworthy.
4499 // * Add a successor indication. The LockWord is currently encoded as
4500 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4501 // to provide the usual futile-wakeup optimization.
4502 // See RTStt for details.
4503 // * Consider schedctl.sc_nopreempt to cover the critical section.
4504 //
4505
4506
4507 typedef volatile intptr_t MutexT ; // Mux Lock-word
4508 enum MuxBits { LOCKBIT = 1 } ;
4509
4510 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4511 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4512 if (w == 0) return ;
4513 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4514 return ;
4515 }
4516
4517 TEVENT (muxAcquire - Contention) ;
4518 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4519 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4520 for (;;) {
4521 int its = (os::is_MP() ? 100 : 0) + 1 ;
4522
4523 // Optional spin phase: spin-then-park strategy
4524 while (--its >= 0) {
4525 w = *Lock ;
4526 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4527 return ;
4528 }
4529 }
4530
4531 Self->reset() ;
4532 Self->OnList = intptr_t(Lock) ;
4533 // The following fence() isn't _strictly necessary as the subsequent
4534 // CAS() both serializes execution and ratifies the fetched *Lock value.
4535 OrderAccess::fence();
4536 for (;;) {
4537 w = *Lock ;
4538 if ((w & LOCKBIT) == 0) {
4539 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4540 Self->OnList = 0 ; // hygiene - allows stronger asserts
4541 return ;
4542 }
4543 continue ; // Interference -- *Lock changed -- Just retry
4544 }
4545 assert (w & LOCKBIT, "invariant") ;
4546 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4547 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4548 }
4549
4550 while (Self->OnList != 0) {
4551 Self->park() ;
4552 }
4553 }
4554 }
4555
4556 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4557 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4558 if (w == 0) return ;
4559 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4560 return ;
4561 }
4562
4563 TEVENT (muxAcquire - Contention) ;
4564 ParkEvent * ReleaseAfter = NULL ;
4565 if (ev == NULL) {
4566 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4567 }
4568 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4569 for (;;) {
4570 guarantee (ev->OnList == 0, "invariant") ;
4571 int its = (os::is_MP() ? 100 : 0) + 1 ;
4572
4573 // Optional spin phase: spin-then-park strategy
4574 while (--its >= 0) {
4575 w = *Lock ;
4576 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4577 if (ReleaseAfter != NULL) {
4578 ParkEvent::Release (ReleaseAfter) ;
4579 }
4580 return ;
4581 }
4582 }
4583
4584 ev->reset() ;
4585 ev->OnList = intptr_t(Lock) ;
4586 // The following fence() isn't _strictly necessary as the subsequent
4587 // CAS() both serializes execution and ratifies the fetched *Lock value.
4588 OrderAccess::fence();
4589 for (;;) {
4590 w = *Lock ;
4591 if ((w & LOCKBIT) == 0) {
4592 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4593 ev->OnList = 0 ;
4594 // We call ::Release while holding the outer lock, thus
4595 // artificially lengthening the critical section.
4596 // Consider deferring the ::Release() until the subsequent unlock(),
4597 // after we've dropped the outer lock.
4598 if (ReleaseAfter != NULL) {
4599 ParkEvent::Release (ReleaseAfter) ;
4600 }
4601 return ;
4602 }
4603 continue ; // Interference -- *Lock changed -- Just retry
4604 }
4605 assert (w & LOCKBIT, "invariant") ;
4606 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4607 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4608 }
4609
4610 while (ev->OnList != 0) {
4611 ev->park() ;
4612 }
4613 }
4614 }
4615
4616 // Release() must extract a successor from the list and then wake that thread.
4617 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4618 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4619 // Release() would :
4620 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4621 // (B) Extract a successor from the private list "in-hand"
4622 // (C) attempt to CAS() the residual back into *Lock over null.
4623 // If there were any newly arrived threads and the CAS() would fail.
4624 // In that case Release() would detach the RATs, re-merge the list in-hand
4625 // with the RATs and repeat as needed. Alternately, Release() might
4626 // detach and extract a successor, but then pass the residual list to the wakee.
4627 // The wakee would be responsible for reattaching and remerging before it
4628 // competed for the lock.
4629 //
4630 // Both "pop" and DMR are immune from ABA corruption -- there can be
4631 // multiple concurrent pushers, but only one popper or detacher.
4632 // This implementation pops from the head of the list. This is unfair,
4633 // but tends to provide excellent throughput as hot threads remain hot.
4634 // (We wake recently run threads first).
4635
4636 void Thread::muxRelease (volatile intptr_t * Lock) {
4637 for (;;) {
4638 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4639 assert (w & LOCKBIT, "invariant") ;
4640 if (w == LOCKBIT) return ;
4641 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4642 assert (List != NULL, "invariant") ;
4643 assert (List->OnList == intptr_t(Lock), "invariant") ;
4644 ParkEvent * nxt = List->ListNext ;
4645
4646 // The following CAS() releases the lock and pops the head element.
4647 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4648 continue ;
4649 }
4650 List->OnList = 0 ;
4651 OrderAccess::fence() ;
4652 List->unpark () ;
4653 return ;
4654 }
4655 }
4656
4657
4658 void Threads::verify() {
4659 ALL_JAVA_THREADS(p) {
4660 p->verify();
4661 }
4662 VMThread* thread = VMThread::vm_thread();
4663 if (thread != NULL) thread->verify();
4664 }