1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jvmtifiles/jvmtiEnv.hpp"
36 #include "memory/gcLocker.inline.hpp"
37 #include "memory/metaspaceShared.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "memory/universe.inline.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/objArrayOop.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/symbol.hpp"
44 #include "prims/jvm_misc.hpp"
45 #include "prims/jvmtiExport.hpp"
46 #include "prims/jvmtiThreadState.hpp"
47 #include "prims/privilegedStack.hpp"
48 #include "runtime/arguments.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/deoptimization.hpp"
51 #include "runtime/fprofiler.hpp"
52 #include "runtime/frame.inline.hpp"
53 #include "runtime/init.hpp"
54 #include "runtime/interfaceSupport.hpp"
55 #include "runtime/java.hpp"
56 #include "runtime/javaCalls.hpp"
57 #include "runtime/jniPeriodicChecker.hpp"
58 #include "runtime/memprofiler.hpp"
59 #include "runtime/mutexLocker.hpp"
60 #include "runtime/objectMonitor.hpp"
61 #include "runtime/orderAccess.inline.hpp"
62 #include "runtime/osThread.hpp"
63 #include "runtime/safepoint.hpp"
64 #include "runtime/sharedRuntime.hpp"
65 #include "runtime/statSampler.hpp"
66 #include "runtime/stubRoutines.hpp"
67 #include "runtime/task.hpp"
68 #include "runtime/thread.inline.hpp"
69 #include "runtime/threadCritical.hpp"
70 #include "runtime/threadLocalStorage.hpp"
71 #include "runtime/vframe.hpp"
72 #include "runtime/vframeArray.hpp"
73 #include "runtime/vframe_hp.hpp"
74 #include "runtime/vmThread.hpp"
75 #include "runtime/vm_operations.hpp"
76 #include "services/attachListener.hpp"
77 #include "services/management.hpp"
78 #include "services/memTracker.hpp"
79 #include "services/threadService.hpp"
80 #include "trace/tracing.hpp"
81 #include "trace/traceMacros.hpp"
82 #include "utilities/defaultStream.hpp"
83 #include "utilities/dtrace.hpp"
84 #include "utilities/events.hpp"
85 #include "utilities/preserveException.hpp"
86 #include "utilities/macros.hpp"
87 #ifdef TARGET_OS_FAMILY_linux
88 # include "os_linux.inline.hpp"
89 #endif
90 #ifdef TARGET_OS_FAMILY_solaris
91 # include "os_solaris.inline.hpp"
92 #endif
93 #ifdef TARGET_OS_FAMILY_windows
94 # include "os_windows.inline.hpp"
95 #endif
96 #ifdef TARGET_OS_FAMILY_bsd
97 # include "os_bsd.inline.hpp"
98 #endif
99 #if INCLUDE_ALL_GCS
100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
102 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
103 #endif // INCLUDE_ALL_GCS
104 #ifdef COMPILER1
105 #include "c1/c1_Compiler.hpp"
106 #endif
107 #ifdef COMPILER2
108 #include "opto/c2compiler.hpp"
109 #include "opto/idealGraphPrinter.hpp"
110 #endif
111 #if INCLUDE_RTM_OPT
112 #include "runtime/rtmLocking.hpp"
113 #endif
114
115 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
116
117 #ifdef DTRACE_ENABLED
118
119 // Only bother with this argument setup if dtrace is available
120
121 #ifndef USDT2
122 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
123 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
124 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
125 intptr_t, intptr_t, bool);
126 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
127 intptr_t, intptr_t, bool);
128
129 #define DTRACE_THREAD_PROBE(probe, javathread) \
130 { \
131 ResourceMark rm(this); \
132 int len = 0; \
133 const char* name = (javathread)->get_thread_name(); \
134 len = strlen(name); \
135 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
136 name, len, \
137 java_lang_Thread::thread_id((javathread)->threadObj()), \
138 (javathread)->osthread()->thread_id(), \
139 java_lang_Thread::is_daemon((javathread)->threadObj())); \
140 }
141
142 #else /* USDT2 */
143
144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
146
147 #define DTRACE_THREAD_PROBE(probe, javathread) \
148 { \
149 ResourceMark rm(this); \
150 int len = 0; \
151 const char* name = (javathread)->get_thread_name(); \
152 len = strlen(name); \
153 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
154 (char *) name, len, \
155 java_lang_Thread::thread_id((javathread)->threadObj()), \
156 (uintptr_t) (javathread)->osthread()->thread_id(), \
157 java_lang_Thread::is_daemon((javathread)->threadObj())); \
158 }
159
160 #endif /* USDT2 */
161
162 #else // ndef DTRACE_ENABLED
163
164 #define DTRACE_THREAD_PROBE(probe, javathread)
165
166 #endif // ndef DTRACE_ENABLED
167
168
169 // Class hierarchy
170 // - Thread
171 // - VMThread
172 // - WatcherThread
173 // - ConcurrentMarkSweepThread
174 // - JavaThread
175 // - CompilerThread
176
177 // ======= Thread ========
178 // Support for forcing alignment of thread objects for biased locking
179 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
180 if (UseBiasedLocking) {
181 const int alignment = markOopDesc::biased_lock_alignment;
182 size_t aligned_size = size + (alignment - sizeof(intptr_t));
183 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
184 : AllocateHeap(aligned_size, flags, CURRENT_PC,
185 AllocFailStrategy::RETURN_NULL);
186 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
187 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
188 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
189 "JavaThread alignment code overflowed allocated storage");
190 if (TraceBiasedLocking) {
191 if (aligned_addr != real_malloc_addr)
192 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
193 real_malloc_addr, aligned_addr);
194 }
195 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
196 return aligned_addr;
197 } else {
198 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
199 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
200 }
201 }
202
203 void Thread::operator delete(void* p) {
204 if (UseBiasedLocking) {
205 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
206 FreeHeap(real_malloc_addr, mtThread);
207 } else {
208 FreeHeap(p, mtThread);
209 }
210 }
211
212
213 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
214 // JavaThread
215
216
217 Thread::Thread() {
218 // stack and get_thread
219 set_stack_base(NULL);
220 set_stack_size(0);
221 set_self_raw_id(0);
222 set_lgrp_id(-1);
223
224 // allocated data structures
225 set_osthread(NULL);
226 set_resource_area(new (mtThread)ResourceArea());
227 DEBUG_ONLY(_current_resource_mark = NULL;)
228 set_handle_area(new (mtThread) HandleArea(NULL));
229 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
230 set_active_handles(NULL);
231 set_free_handle_block(NULL);
232 set_last_handle_mark(NULL);
233
234 // This initial value ==> never claimed.
235 _oops_do_parity = 0;
236
237 _metadata_on_stack_buffer = NULL;
238
239 // the handle mark links itself to last_handle_mark
240 new HandleMark(this);
241
242 // plain initialization
243 debug_only(_owned_locks = NULL;)
244 debug_only(_allow_allocation_count = 0;)
245 NOT_PRODUCT(_allow_safepoint_count = 0;)
246 NOT_PRODUCT(_skip_gcalot = false;)
247 _jvmti_env_iteration_count = 0;
248 set_allocated_bytes(0);
249 _vm_operation_started_count = 0;
250 _vm_operation_completed_count = 0;
251 _current_pending_monitor = NULL;
252 _current_pending_monitor_is_from_java = true;
253 _current_waiting_monitor = NULL;
254 _num_nested_signal = 0;
255 omFreeList = NULL ;
256 omFreeCount = 0 ;
257 omFreeProvision = 32 ;
258 omInUseList = NULL ;
259 omInUseCount = 0 ;
260
261 #ifdef ASSERT
262 _visited_for_critical_count = false;
263 #endif
264
265 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
266 _suspend_flags = 0;
267
268 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
269 _hashStateX = os::random() ;
270 _hashStateY = 842502087 ;
271 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
272 _hashStateW = 273326509 ;
273
274 _OnTrap = 0 ;
275 _schedctl = NULL ;
276 _Stalled = 0 ;
277 _TypeTag = 0x2BAD ;
278
279 // Many of the following fields are effectively final - immutable
280 // Note that nascent threads can't use the Native Monitor-Mutex
281 // construct until the _MutexEvent is initialized ...
282 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
283 // we might instead use a stack of ParkEvents that we could provision on-demand.
284 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
285 // and ::Release()
286 _ParkEvent = ParkEvent::Allocate (this) ;
287 _SleepEvent = ParkEvent::Allocate (this) ;
288 _MutexEvent = ParkEvent::Allocate (this) ;
289 _MuxEvent = ParkEvent::Allocate (this) ;
290
291 #ifdef CHECK_UNHANDLED_OOPS
292 if (CheckUnhandledOops) {
293 _unhandled_oops = new UnhandledOops(this);
294 }
295 #endif // CHECK_UNHANDLED_OOPS
296 #ifdef ASSERT
297 if (UseBiasedLocking) {
298 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
299 assert(this == _real_malloc_address ||
300 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
301 "bug in forced alignment of thread objects");
302 }
303 #endif /* ASSERT */
304 }
305
306 void Thread::initialize_thread_local_storage() {
307 // Note: Make sure this method only calls
308 // non-blocking operations. Otherwise, it might not work
309 // with the thread-startup/safepoint interaction.
310
311 // During Java thread startup, safepoint code should allow this
312 // method to complete because it may need to allocate memory to
313 // store information for the new thread.
314
315 // initialize structure dependent on thread local storage
316 ThreadLocalStorage::set_thread(this);
317 }
318
319 void Thread::record_stack_base_and_size() {
320 set_stack_base(os::current_stack_base());
321 set_stack_size(os::current_stack_size());
322 if (is_Java_thread()) {
323 ((JavaThread*) this)->set_stack_overflow_limit();
324 }
325 // CR 7190089: on Solaris, primordial thread's stack is adjusted
326 // in initialize_thread(). Without the adjustment, stack size is
327 // incorrect if stack is set to unlimited (ulimit -s unlimited).
328 // So far, only Solaris has real implementation of initialize_thread().
329 //
330 // set up any platform-specific state.
331 os::initialize_thread(this);
332
333 #if INCLUDE_NMT
334 // record thread's native stack, stack grows downward
335 address stack_low_addr = stack_base() - stack_size();
336 MemTracker::record_thread_stack(stack_low_addr, stack_size());
337 #endif // INCLUDE_NMT
338 }
339
340
341 Thread::~Thread() {
342 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
343 ObjectSynchronizer::omFlush (this) ;
344
345 EVENT_THREAD_DESTRUCT(this);
346
347 // stack_base can be NULL if the thread is never started or exited before
348 // record_stack_base_and_size called. Although, we would like to ensure
349 // that all started threads do call record_stack_base_and_size(), there is
350 // not proper way to enforce that.
351 #if INCLUDE_NMT
352 if (_stack_base != NULL) {
353 address low_stack_addr = stack_base() - stack_size();
354 MemTracker::release_thread_stack(low_stack_addr, stack_size());
355 #ifdef ASSERT
356 set_stack_base(NULL);
357 #endif
358 }
359 #endif // INCLUDE_NMT
360
361 // deallocate data structures
362 delete resource_area();
363 // since the handle marks are using the handle area, we have to deallocated the root
364 // handle mark before deallocating the thread's handle area,
365 assert(last_handle_mark() != NULL, "check we have an element");
366 delete last_handle_mark();
367 assert(last_handle_mark() == NULL, "check we have reached the end");
368
369 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
370 // We NULL out the fields for good hygiene.
371 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
372 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
373 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
374 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
375
376 delete handle_area();
377 delete metadata_handles();
378
379 // osthread() can be NULL, if creation of thread failed.
380 if (osthread() != NULL) os::free_thread(osthread());
381
382 delete _SR_lock;
383
384 // clear thread local storage if the Thread is deleting itself
385 if (this == Thread::current()) {
386 ThreadLocalStorage::set_thread(NULL);
387 } else {
388 // In the case where we're not the current thread, invalidate all the
389 // caches in case some code tries to get the current thread or the
390 // thread that was destroyed, and gets stale information.
391 ThreadLocalStorage::invalidate_all();
392 }
393 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
394 }
395
396 // NOTE: dummy function for assertion purpose.
397 void Thread::run() {
398 ShouldNotReachHere();
399 }
400
401 #ifdef ASSERT
402 // Private method to check for dangling thread pointer
403 void check_for_dangling_thread_pointer(Thread *thread) {
404 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
405 "possibility of dangling Thread pointer");
406 }
407 #endif
408
409
410 #ifndef PRODUCT
411 // Tracing method for basic thread operations
412 void Thread::trace(const char* msg, const Thread* const thread) {
413 if (!TraceThreadEvents) return;
414 ResourceMark rm;
415 ThreadCritical tc;
416 const char *name = "non-Java thread";
417 int prio = -1;
418 if (thread->is_Java_thread()
419 && !thread->is_Compiler_thread()) {
420 // The Threads_lock must be held to get information about
421 // this thread but may not be in some situations when
422 // tracing thread events.
423 bool release_Threads_lock = false;
424 if (!Threads_lock->owned_by_self()) {
425 Threads_lock->lock();
426 release_Threads_lock = true;
427 }
428 JavaThread* jt = (JavaThread *)thread;
429 name = (char *)jt->get_thread_name();
430 oop thread_oop = jt->threadObj();
431 if (thread_oop != NULL) {
432 prio = java_lang_Thread::priority(thread_oop);
433 }
434 if (release_Threads_lock) {
435 Threads_lock->unlock();
436 }
437 }
438 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
439 }
440 #endif
441
442
443 ThreadPriority Thread::get_priority(const Thread* const thread) {
444 trace("get priority", thread);
445 ThreadPriority priority;
446 // Can return an error!
447 (void)os::get_priority(thread, priority);
448 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
449 return priority;
450 }
451
452 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
453 trace("set priority", thread);
454 debug_only(check_for_dangling_thread_pointer(thread);)
455 // Can return an error!
456 (void)os::set_priority(thread, priority);
457 }
458
459
460 void Thread::start(Thread* thread) {
461 trace("start", thread);
462 // Start is different from resume in that its safety is guaranteed by context or
463 // being called from a Java method synchronized on the Thread object.
464 if (!DisableStartThread) {
465 if (thread->is_Java_thread()) {
466 // Initialize the thread state to RUNNABLE before starting this thread.
467 // Can not set it after the thread started because we do not know the
468 // exact thread state at that time. It could be in MONITOR_WAIT or
469 // in SLEEPING or some other state.
470 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
471 java_lang_Thread::RUNNABLE);
472 }
473 os::start_thread(thread);
474 }
475 }
476
477 // Enqueue a VM_Operation to do the job for us - sometime later
478 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
479 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
480 VMThread::execute(vm_stop);
481 }
482
483
484 //
485 // Check if an external suspend request has completed (or has been
486 // cancelled). Returns true if the thread is externally suspended and
487 // false otherwise.
488 //
489 // The bits parameter returns information about the code path through
490 // the routine. Useful for debugging:
491 //
492 // set in is_ext_suspend_completed():
493 // 0x00000001 - routine was entered
494 // 0x00000010 - routine return false at end
495 // 0x00000100 - thread exited (return false)
496 // 0x00000200 - suspend request cancelled (return false)
497 // 0x00000400 - thread suspended (return true)
498 // 0x00001000 - thread is in a suspend equivalent state (return true)
499 // 0x00002000 - thread is native and walkable (return true)
500 // 0x00004000 - thread is native_trans and walkable (needed retry)
501 //
502 // set in wait_for_ext_suspend_completion():
503 // 0x00010000 - routine was entered
504 // 0x00020000 - suspend request cancelled before loop (return false)
505 // 0x00040000 - thread suspended before loop (return true)
506 // 0x00080000 - suspend request cancelled in loop (return false)
507 // 0x00100000 - thread suspended in loop (return true)
508 // 0x00200000 - suspend not completed during retry loop (return false)
509 //
510
511 // Helper class for tracing suspend wait debug bits.
512 //
513 // 0x00000100 indicates that the target thread exited before it could
514 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
515 // 0x00080000 each indicate a cancelled suspend request so they don't
516 // count as wait failures either.
517 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
518
519 class TraceSuspendDebugBits : public StackObj {
520 private:
521 JavaThread * jt;
522 bool is_wait;
523 bool called_by_wait; // meaningful when !is_wait
524 uint32_t * bits;
525
526 public:
527 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
528 uint32_t *_bits) {
529 jt = _jt;
530 is_wait = _is_wait;
531 called_by_wait = _called_by_wait;
532 bits = _bits;
533 }
534
535 ~TraceSuspendDebugBits() {
536 if (!is_wait) {
537 #if 1
538 // By default, don't trace bits for is_ext_suspend_completed() calls.
539 // That trace is very chatty.
540 return;
541 #else
542 if (!called_by_wait) {
543 // If tracing for is_ext_suspend_completed() is enabled, then only
544 // trace calls to it from wait_for_ext_suspend_completion()
545 return;
546 }
547 #endif
548 }
549
550 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
551 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
552 MutexLocker ml(Threads_lock); // needed for get_thread_name()
553 ResourceMark rm;
554
555 tty->print_cr(
556 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
557 jt->get_thread_name(), *bits);
558
559 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
560 }
561 }
562 }
563 };
564 #undef DEBUG_FALSE_BITS
565
566
567 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
568 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
569
570 bool did_trans_retry = false; // only do thread_in_native_trans retry once
571 bool do_trans_retry; // flag to force the retry
572
573 *bits |= 0x00000001;
574
575 do {
576 do_trans_retry = false;
577
578 if (is_exiting()) {
579 // Thread is in the process of exiting. This is always checked
580 // first to reduce the risk of dereferencing a freed JavaThread.
581 *bits |= 0x00000100;
582 return false;
583 }
584
585 if (!is_external_suspend()) {
586 // Suspend request is cancelled. This is always checked before
587 // is_ext_suspended() to reduce the risk of a rogue resume
588 // confusing the thread that made the suspend request.
589 *bits |= 0x00000200;
590 return false;
591 }
592
593 if (is_ext_suspended()) {
594 // thread is suspended
595 *bits |= 0x00000400;
596 return true;
597 }
598
599 // Now that we no longer do hard suspends of threads running
600 // native code, the target thread can be changing thread state
601 // while we are in this routine:
602 //
603 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
604 //
605 // We save a copy of the thread state as observed at this moment
606 // and make our decision about suspend completeness based on the
607 // copy. This closes the race where the thread state is seen as
608 // _thread_in_native_trans in the if-thread_blocked check, but is
609 // seen as _thread_blocked in if-thread_in_native_trans check.
610 JavaThreadState save_state = thread_state();
611
612 if (save_state == _thread_blocked && is_suspend_equivalent()) {
613 // If the thread's state is _thread_blocked and this blocking
614 // condition is known to be equivalent to a suspend, then we can
615 // consider the thread to be externally suspended. This means that
616 // the code that sets _thread_blocked has been modified to do
617 // self-suspension if the blocking condition releases. We also
618 // used to check for CONDVAR_WAIT here, but that is now covered by
619 // the _thread_blocked with self-suspension check.
620 //
621 // Return true since we wouldn't be here unless there was still an
622 // external suspend request.
623 *bits |= 0x00001000;
624 return true;
625 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
626 // Threads running native code will self-suspend on native==>VM/Java
627 // transitions. If its stack is walkable (should always be the case
628 // unless this function is called before the actual java_suspend()
629 // call), then the wait is done.
630 *bits |= 0x00002000;
631 return true;
632 } else if (!called_by_wait && !did_trans_retry &&
633 save_state == _thread_in_native_trans &&
634 frame_anchor()->walkable()) {
635 // The thread is transitioning from thread_in_native to another
636 // thread state. check_safepoint_and_suspend_for_native_trans()
637 // will force the thread to self-suspend. If it hasn't gotten
638 // there yet we may have caught the thread in-between the native
639 // code check above and the self-suspend. Lucky us. If we were
640 // called by wait_for_ext_suspend_completion(), then it
641 // will be doing the retries so we don't have to.
642 //
643 // Since we use the saved thread state in the if-statement above,
644 // there is a chance that the thread has already transitioned to
645 // _thread_blocked by the time we get here. In that case, we will
646 // make a single unnecessary pass through the logic below. This
647 // doesn't hurt anything since we still do the trans retry.
648
649 *bits |= 0x00004000;
650
651 // Once the thread leaves thread_in_native_trans for another
652 // thread state, we break out of this retry loop. We shouldn't
653 // need this flag to prevent us from getting back here, but
654 // sometimes paranoia is good.
655 did_trans_retry = true;
656
657 // We wait for the thread to transition to a more usable state.
658 for (int i = 1; i <= SuspendRetryCount; i++) {
659 // We used to do an "os::yield_all(i)" call here with the intention
660 // that yielding would increase on each retry. However, the parameter
661 // is ignored on Linux which means the yield didn't scale up. Waiting
662 // on the SR_lock below provides a much more predictable scale up for
663 // the delay. It also provides a simple/direct point to check for any
664 // safepoint requests from the VMThread
665
666 // temporarily drops SR_lock while doing wait with safepoint check
667 // (if we're a JavaThread - the WatcherThread can also call this)
668 // and increase delay with each retry
669 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
670
671 // check the actual thread state instead of what we saved above
672 if (thread_state() != _thread_in_native_trans) {
673 // the thread has transitioned to another thread state so
674 // try all the checks (except this one) one more time.
675 do_trans_retry = true;
676 break;
677 }
678 } // end retry loop
679
680
681 }
682 } while (do_trans_retry);
683
684 *bits |= 0x00000010;
685 return false;
686 }
687
688 //
689 // Wait for an external suspend request to complete (or be cancelled).
690 // Returns true if the thread is externally suspended and false otherwise.
691 //
692 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
693 uint32_t *bits) {
694 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
695 false /* !called_by_wait */, bits);
696
697 // local flag copies to minimize SR_lock hold time
698 bool is_suspended;
699 bool pending;
700 uint32_t reset_bits;
701
702 // set a marker so is_ext_suspend_completed() knows we are the caller
703 *bits |= 0x00010000;
704
705 // We use reset_bits to reinitialize the bits value at the top of
706 // each retry loop. This allows the caller to make use of any
707 // unused bits for their own marking purposes.
708 reset_bits = *bits;
709
710 {
711 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
712 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
713 delay, bits);
714 pending = is_external_suspend();
715 }
716 // must release SR_lock to allow suspension to complete
717
718 if (!pending) {
719 // A cancelled suspend request is the only false return from
720 // is_ext_suspend_completed() that keeps us from entering the
721 // retry loop.
722 *bits |= 0x00020000;
723 return false;
724 }
725
726 if (is_suspended) {
727 *bits |= 0x00040000;
728 return true;
729 }
730
731 for (int i = 1; i <= retries; i++) {
732 *bits = reset_bits; // reinit to only track last retry
733
734 // We used to do an "os::yield_all(i)" call here with the intention
735 // that yielding would increase on each retry. However, the parameter
736 // is ignored on Linux which means the yield didn't scale up. Waiting
737 // on the SR_lock below provides a much more predictable scale up for
738 // the delay. It also provides a simple/direct point to check for any
739 // safepoint requests from the VMThread
740
741 {
742 MutexLocker ml(SR_lock());
743 // wait with safepoint check (if we're a JavaThread - the WatcherThread
744 // can also call this) and increase delay with each retry
745 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
746
747 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
748 delay, bits);
749
750 // It is possible for the external suspend request to be cancelled
751 // (by a resume) before the actual suspend operation is completed.
752 // Refresh our local copy to see if we still need to wait.
753 pending = is_external_suspend();
754 }
755
756 if (!pending) {
757 // A cancelled suspend request is the only false return from
758 // is_ext_suspend_completed() that keeps us from staying in the
759 // retry loop.
760 *bits |= 0x00080000;
761 return false;
762 }
763
764 if (is_suspended) {
765 *bits |= 0x00100000;
766 return true;
767 }
768 } // end retry loop
769
770 // thread did not suspend after all our retries
771 *bits |= 0x00200000;
772 return false;
773 }
774
775 #ifndef PRODUCT
776 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
777
778 // This should not need to be atomic as the only way for simultaneous
779 // updates is via interrupts. Even then this should be rare or non-existant
780 // and we don't care that much anyway.
781
782 int index = _jmp_ring_index;
783 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
784 _jmp_ring[index]._target = (intptr_t) target;
785 _jmp_ring[index]._instruction = (intptr_t) instr;
786 _jmp_ring[index]._file = file;
787 _jmp_ring[index]._line = line;
788 }
789 #endif /* PRODUCT */
790
791 // Called by flat profiler
792 // Callers have already called wait_for_ext_suspend_completion
793 // The assertion for that is currently too complex to put here:
794 bool JavaThread::profile_last_Java_frame(frame* _fr) {
795 bool gotframe = false;
796 // self suspension saves needed state.
797 if (has_last_Java_frame() && _anchor.walkable()) {
798 *_fr = pd_last_frame();
799 gotframe = true;
800 }
801 return gotframe;
802 }
803
804 void Thread::interrupt(Thread* thread) {
805 trace("interrupt", thread);
806 debug_only(check_for_dangling_thread_pointer(thread);)
807 os::interrupt(thread);
808 }
809
810 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
811 trace("is_interrupted", thread);
812 debug_only(check_for_dangling_thread_pointer(thread);)
813 // Note: If clear_interrupted==false, this simply fetches and
814 // returns the value of the field osthread()->interrupted().
815 return os::is_interrupted(thread, clear_interrupted);
816 }
817
818
819 // GC Support
820 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
821 jint thread_parity = _oops_do_parity;
822 if (thread_parity != strong_roots_parity) {
823 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
824 if (res == thread_parity) {
825 return true;
826 } else {
827 guarantee(res == strong_roots_parity, "Or else what?");
828 assert(SharedHeap::heap()->workers()->active_workers() > 0,
829 "Should only fail when parallel.");
830 return false;
831 }
832 }
833 assert(SharedHeap::heap()->workers()->active_workers() > 0,
834 "Should only fail when parallel.");
835 return false;
836 }
837
838 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
839 active_handles()->oops_do(f);
840 // Do oop for ThreadShadow
841 f->do_oop((oop*)&_pending_exception);
842 handle_area()->oops_do(f);
843 }
844
845 void Thread::nmethods_do(CodeBlobClosure* cf) {
846 // no nmethods in a generic thread...
847 }
848
849 void Thread::metadata_do(void f(Metadata*)) {
850 if (metadata_handles() != NULL) {
851 for (int i = 0; i< metadata_handles()->length(); i++) {
852 f(metadata_handles()->at(i));
853 }
854 }
855 }
856
857 void Thread::print_on(outputStream* st) const {
858 // get_priority assumes osthread initialized
859 if (osthread() != NULL) {
860 int os_prio;
861 if (os::get_native_priority(this, &os_prio) == OS_OK) {
862 st->print("os_prio=%d ", os_prio);
863 }
864 st->print("tid=" INTPTR_FORMAT " ", this);
865 ext().print_on(st);
866 osthread()->print_on(st);
867 }
868 debug_only(if (WizardMode) print_owned_locks_on(st);)
869 }
870
871 // Thread::print_on_error() is called by fatal error handler. Don't use
872 // any lock or allocate memory.
873 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
874 if (is_VM_thread()) st->print("VMThread");
875 else if (is_Compiler_thread()) st->print("CompilerThread");
876 else if (is_Java_thread()) st->print("JavaThread");
877 else if (is_GC_task_thread()) st->print("GCTaskThread");
878 else if (is_Watcher_thread()) st->print("WatcherThread");
879 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
880 else st->print("Thread");
881
882 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
883 _stack_base - _stack_size, _stack_base);
884
885 if (osthread()) {
886 st->print(" [id=%d]", osthread()->thread_id());
887 }
888 }
889
890 #ifdef ASSERT
891 void Thread::print_owned_locks_on(outputStream* st) const {
892 Monitor *cur = _owned_locks;
893 if (cur == NULL) {
894 st->print(" (no locks) ");
895 } else {
896 st->print_cr(" Locks owned:");
897 while(cur) {
898 cur->print_on(st);
899 cur = cur->next();
900 }
901 }
902 }
903
904 static int ref_use_count = 0;
905
906 bool Thread::owns_locks_but_compiled_lock() const {
907 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
908 if (cur != Compile_lock) return true;
909 }
910 return false;
911 }
912
913
914 #endif
915
916 #ifndef PRODUCT
917
918 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
919 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
920 // no threads which allow_vm_block's are held
921 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
922 // Check if current thread is allowed to block at a safepoint
923 if (!(_allow_safepoint_count == 0))
924 fatal("Possible safepoint reached by thread that does not allow it");
925 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
926 fatal("LEAF method calling lock?");
927 }
928
929 #ifdef ASSERT
930 if (potential_vm_operation && is_Java_thread()
931 && !Universe::is_bootstrapping()) {
932 // Make sure we do not hold any locks that the VM thread also uses.
933 // This could potentially lead to deadlocks
934 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
935 // Threads_lock is special, since the safepoint synchronization will not start before this is
936 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
937 // since it is used to transfer control between JavaThreads and the VMThread
938 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
939 if ( (cur->allow_vm_block() &&
940 cur != Threads_lock &&
941 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
942 cur != VMOperationRequest_lock &&
943 cur != VMOperationQueue_lock) ||
944 cur->rank() == Mutex::special) {
945 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
946 }
947 }
948 }
949
950 if (GCALotAtAllSafepoints) {
951 // We could enter a safepoint here and thus have a gc
952 InterfaceSupport::check_gc_alot();
953 }
954 #endif
955 }
956 #endif
957
958 bool Thread::is_in_stack(address adr) const {
959 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
960 address end = os::current_stack_pointer();
961 // Allow non Java threads to call this without stack_base
962 if (_stack_base == NULL) return true;
963 if (stack_base() >= adr && adr >= end) return true;
964
965 return false;
966 }
967
968
969 bool Thread::is_in_usable_stack(address adr) const {
970 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
971 size_t usable_stack_size = _stack_size - stack_guard_size;
972
973 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
974 }
975
976
977 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
978 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
979 // used for compilation in the future. If that change is made, the need for these methods
980 // should be revisited, and they should be removed if possible.
981
982 bool Thread::is_lock_owned(address adr) const {
983 return on_local_stack(adr);
984 }
985
986 bool Thread::set_as_starting_thread() {
987 // NOTE: this must be called inside the main thread.
988 return os::create_main_thread((JavaThread*)this);
989 }
990
991 static void initialize_class(Symbol* class_name, TRAPS) {
992 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
993 InstanceKlass::cast(klass)->initialize(CHECK);
994 }
995
996
997 // Creates the initial ThreadGroup
998 static Handle create_initial_thread_group(TRAPS) {
999 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1000 instanceKlassHandle klass (THREAD, k);
1001
1002 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1003 {
1004 JavaValue result(T_VOID);
1005 JavaCalls::call_special(&result,
1006 system_instance,
1007 klass,
1008 vmSymbols::object_initializer_name(),
1009 vmSymbols::void_method_signature(),
1010 CHECK_NH);
1011 }
1012 Universe::set_system_thread_group(system_instance());
1013
1014 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1015 {
1016 JavaValue result(T_VOID);
1017 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1018 JavaCalls::call_special(&result,
1019 main_instance,
1020 klass,
1021 vmSymbols::object_initializer_name(),
1022 vmSymbols::threadgroup_string_void_signature(),
1023 system_instance,
1024 string,
1025 CHECK_NH);
1026 }
1027 return main_instance;
1028 }
1029
1030 // Creates the initial Thread
1031 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1032 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1033 instanceKlassHandle klass (THREAD, k);
1034 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1035
1036 java_lang_Thread::set_thread(thread_oop(), thread);
1037 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1038 thread->set_threadObj(thread_oop());
1039
1040 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1041
1042 JavaValue result(T_VOID);
1043 JavaCalls::call_special(&result, thread_oop,
1044 klass,
1045 vmSymbols::object_initializer_name(),
1046 vmSymbols::threadgroup_string_void_signature(),
1047 thread_group,
1048 string,
1049 CHECK_NULL);
1050 return thread_oop();
1051 }
1052
1053 static void call_initializeSystemClass(TRAPS) {
1054 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1055 instanceKlassHandle klass (THREAD, k);
1056
1057 JavaValue result(T_VOID);
1058 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1059 vmSymbols::void_method_signature(), CHECK);
1060 }
1061
1062 char java_runtime_name[128] = "";
1063 char java_runtime_version[128] = "";
1064
1065 // extract the JRE name from sun.misc.Version.java_runtime_name
1066 static const char* get_java_runtime_name(TRAPS) {
1067 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1068 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1069 fieldDescriptor fd;
1070 bool found = k != NULL &&
1071 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1072 vmSymbols::string_signature(), &fd);
1073 if (found) {
1074 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1075 if (name_oop == NULL)
1076 return NULL;
1077 const char* name = java_lang_String::as_utf8_string(name_oop,
1078 java_runtime_name,
1079 sizeof(java_runtime_name));
1080 return name;
1081 } else {
1082 return NULL;
1083 }
1084 }
1085
1086 // extract the JRE version from sun.misc.Version.java_runtime_version
1087 static const char* get_java_runtime_version(TRAPS) {
1088 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1089 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1090 fieldDescriptor fd;
1091 bool found = k != NULL &&
1092 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1093 vmSymbols::string_signature(), &fd);
1094 if (found) {
1095 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1096 if (name_oop == NULL)
1097 return NULL;
1098 const char* name = java_lang_String::as_utf8_string(name_oop,
1099 java_runtime_version,
1100 sizeof(java_runtime_version));
1101 return name;
1102 } else {
1103 return NULL;
1104 }
1105 }
1106
1107 // General purpose hook into Java code, run once when the VM is initialized.
1108 // The Java library method itself may be changed independently from the VM.
1109 static void call_postVMInitHook(TRAPS) {
1110 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1111 instanceKlassHandle klass (THREAD, k);
1112 if (klass.not_null()) {
1113 JavaValue result(T_VOID);
1114 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1115 vmSymbols::void_method_signature(),
1116 CHECK);
1117 }
1118 }
1119
1120 static void reset_vm_info_property(TRAPS) {
1121 // the vm info string
1122 ResourceMark rm(THREAD);
1123 const char *vm_info = VM_Version::vm_info_string();
1124
1125 // java.lang.System class
1126 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1127 instanceKlassHandle klass (THREAD, k);
1128
1129 // setProperty arguments
1130 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1131 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1132
1133 // return value
1134 JavaValue r(T_OBJECT);
1135
1136 // public static String setProperty(String key, String value);
1137 JavaCalls::call_static(&r,
1138 klass,
1139 vmSymbols::setProperty_name(),
1140 vmSymbols::string_string_string_signature(),
1141 key_str,
1142 value_str,
1143 CHECK);
1144 }
1145
1146
1147 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1148 assert(thread_group.not_null(), "thread group should be specified");
1149 assert(threadObj() == NULL, "should only create Java thread object once");
1150
1151 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1152 instanceKlassHandle klass (THREAD, k);
1153 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1154
1155 java_lang_Thread::set_thread(thread_oop(), this);
1156 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1157 set_threadObj(thread_oop());
1158
1159 JavaValue result(T_VOID);
1160 if (thread_name != NULL) {
1161 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1162 // Thread gets assigned specified name and null target
1163 JavaCalls::call_special(&result,
1164 thread_oop,
1165 klass,
1166 vmSymbols::object_initializer_name(),
1167 vmSymbols::threadgroup_string_void_signature(),
1168 thread_group, // Argument 1
1169 name, // Argument 2
1170 THREAD);
1171 } else {
1172 // Thread gets assigned name "Thread-nnn" and null target
1173 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1174 JavaCalls::call_special(&result,
1175 thread_oop,
1176 klass,
1177 vmSymbols::object_initializer_name(),
1178 vmSymbols::threadgroup_runnable_void_signature(),
1179 thread_group, // Argument 1
1180 Handle(), // Argument 2
1181 THREAD);
1182 }
1183
1184
1185 if (daemon) {
1186 java_lang_Thread::set_daemon(thread_oop());
1187 }
1188
1189 if (HAS_PENDING_EXCEPTION) {
1190 return;
1191 }
1192
1193 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1194 Handle threadObj(this, this->threadObj());
1195
1196 JavaCalls::call_special(&result,
1197 thread_group,
1198 group,
1199 vmSymbols::add_method_name(),
1200 vmSymbols::thread_void_signature(),
1201 threadObj, // Arg 1
1202 THREAD);
1203
1204
1205 }
1206
1207 // NamedThread -- non-JavaThread subclasses with multiple
1208 // uniquely named instances should derive from this.
1209 NamedThread::NamedThread() : Thread() {
1210 _name = NULL;
1211 _processed_thread = NULL;
1212 }
1213
1214 NamedThread::~NamedThread() {
1215 if (_name != NULL) {
1216 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1217 _name = NULL;
1218 }
1219 }
1220
1221 void NamedThread::set_name(const char* format, ...) {
1222 guarantee(_name == NULL, "Only get to set name once.");
1223 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1224 guarantee(_name != NULL, "alloc failure");
1225 va_list ap;
1226 va_start(ap, format);
1227 jio_vsnprintf(_name, max_name_len, format, ap);
1228 va_end(ap);
1229 }
1230
1231 // ======= WatcherThread ========
1232
1233 // The watcher thread exists to simulate timer interrupts. It should
1234 // be replaced by an abstraction over whatever native support for
1235 // timer interrupts exists on the platform.
1236
1237 WatcherThread* WatcherThread::_watcher_thread = NULL;
1238 bool WatcherThread::_startable = false;
1239 volatile bool WatcherThread::_should_terminate = false;
1240
1241 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1242 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1243 if (os::create_thread(this, os::watcher_thread)) {
1244 _watcher_thread = this;
1245
1246 // Set the watcher thread to the highest OS priority which should not be
1247 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1248 // is created. The only normal thread using this priority is the reference
1249 // handler thread, which runs for very short intervals only.
1250 // If the VMThread's priority is not lower than the WatcherThread profiling
1251 // will be inaccurate.
1252 os::set_priority(this, MaxPriority);
1253 if (!DisableStartThread) {
1254 os::start_thread(this);
1255 }
1256 }
1257 }
1258
1259 int WatcherThread::sleep() const {
1260 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1261
1262 // remaining will be zero if there are no tasks,
1263 // causing the WatcherThread to sleep until a task is
1264 // enrolled
1265 int remaining = PeriodicTask::time_to_wait();
1266 int time_slept = 0;
1267
1268 // we expect this to timeout - we only ever get unparked when
1269 // we should terminate or when a new task has been enrolled
1270 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1271
1272 jlong time_before_loop = os::javaTimeNanos();
1273
1274 for (;;) {
1275 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1276 jlong now = os::javaTimeNanos();
1277
1278 if (remaining == 0) {
1279 // if we didn't have any tasks we could have waited for a long time
1280 // consider the time_slept zero and reset time_before_loop
1281 time_slept = 0;
1282 time_before_loop = now;
1283 } else {
1284 // need to recalulate since we might have new tasks in _tasks
1285 time_slept = (int) ((now - time_before_loop) / 1000000);
1286 }
1287
1288 // Change to task list or spurious wakeup of some kind
1289 if (timedout || _should_terminate) {
1290 break;
1291 }
1292
1293 remaining = PeriodicTask::time_to_wait();
1294 if (remaining == 0) {
1295 // Last task was just disenrolled so loop around and wait until
1296 // another task gets enrolled
1297 continue;
1298 }
1299
1300 remaining -= time_slept;
1301 if (remaining <= 0)
1302 break;
1303 }
1304
1305 return time_slept;
1306 }
1307
1308 void WatcherThread::run() {
1309 assert(this == watcher_thread(), "just checking");
1310
1311 this->record_stack_base_and_size();
1312 this->initialize_thread_local_storage();
1313 this->set_active_handles(JNIHandleBlock::allocate_block());
1314 while(!_should_terminate) {
1315 assert(watcher_thread() == Thread::current(), "thread consistency check");
1316 assert(watcher_thread() == this, "thread consistency check");
1317
1318 // Calculate how long it'll be until the next PeriodicTask work
1319 // should be done, and sleep that amount of time.
1320 int time_waited = sleep();
1321
1322 if (is_error_reported()) {
1323 // A fatal error has happened, the error handler(VMError::report_and_die)
1324 // should abort JVM after creating an error log file. However in some
1325 // rare cases, the error handler itself might deadlock. Here we try to
1326 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1327 //
1328 // This code is in WatcherThread because WatcherThread wakes up
1329 // periodically so the fatal error handler doesn't need to do anything;
1330 // also because the WatcherThread is less likely to crash than other
1331 // threads.
1332
1333 for (;;) {
1334 if (!ShowMessageBoxOnError
1335 && (OnError == NULL || OnError[0] == '\0')
1336 && Arguments::abort_hook() == NULL) {
1337 os::sleep(this, 2 * 60 * 1000, false);
1338 fdStream err(defaultStream::output_fd());
1339 err.print_raw_cr("# [ timer expired, abort... ]");
1340 // skip atexit/vm_exit/vm_abort hooks
1341 os::die();
1342 }
1343
1344 // Wake up 5 seconds later, the fatal handler may reset OnError or
1345 // ShowMessageBoxOnError when it is ready to abort.
1346 os::sleep(this, 5 * 1000, false);
1347 }
1348 }
1349
1350 PeriodicTask::real_time_tick(time_waited);
1351 }
1352
1353 // Signal that it is terminated
1354 {
1355 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1356 _watcher_thread = NULL;
1357 Terminator_lock->notify();
1358 }
1359
1360 // Thread destructor usually does this..
1361 ThreadLocalStorage::set_thread(NULL);
1362 }
1363
1364 void WatcherThread::start() {
1365 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1366
1367 if (watcher_thread() == NULL && _startable) {
1368 _should_terminate = false;
1369 // Create the single instance of WatcherThread
1370 new WatcherThread();
1371 }
1372 }
1373
1374 void WatcherThread::make_startable() {
1375 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1376 _startable = true;
1377 }
1378
1379 void WatcherThread::stop() {
1380 {
1381 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1382 _should_terminate = true;
1383 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1384
1385 WatcherThread* watcher = watcher_thread();
1386 if (watcher != NULL)
1387 watcher->unpark();
1388 }
1389
1390 // it is ok to take late safepoints here, if needed
1391 MutexLocker mu(Terminator_lock);
1392
1393 while(watcher_thread() != NULL) {
1394 // This wait should make safepoint checks, wait without a timeout,
1395 // and wait as a suspend-equivalent condition.
1396 //
1397 // Note: If the FlatProfiler is running, then this thread is waiting
1398 // for the WatcherThread to terminate and the WatcherThread, via the
1399 // FlatProfiler task, is waiting for the external suspend request on
1400 // this thread to complete. wait_for_ext_suspend_completion() will
1401 // eventually timeout, but that takes time. Making this wait a
1402 // suspend-equivalent condition solves that timeout problem.
1403 //
1404 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1405 Mutex::_as_suspend_equivalent_flag);
1406 }
1407 }
1408
1409 void WatcherThread::unpark() {
1410 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1411 PeriodicTask_lock->notify();
1412 }
1413
1414 void WatcherThread::print_on(outputStream* st) const {
1415 st->print("\"%s\" ", name());
1416 Thread::print_on(st);
1417 st->cr();
1418 }
1419
1420 // ======= JavaThread ========
1421
1422 // A JavaThread is a normal Java thread
1423
1424 void JavaThread::initialize() {
1425 // Initialize fields
1426
1427 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1428 set_claimed_par_id(UINT_MAX);
1429
1430 set_saved_exception_pc(NULL);
1431 set_threadObj(NULL);
1432 _anchor.clear();
1433 set_entry_point(NULL);
1434 set_jni_functions(jni_functions());
1435 set_callee_target(NULL);
1436 set_vm_result(NULL);
1437 set_vm_result_2(NULL);
1438 set_vframe_array_head(NULL);
1439 set_vframe_array_last(NULL);
1440 set_deferred_locals(NULL);
1441 set_deopt_mark(NULL);
1442 set_deopt_nmethod(NULL);
1443 clear_must_deopt_id();
1444 set_monitor_chunks(NULL);
1445 set_next(NULL);
1446 set_thread_state(_thread_new);
1447 _terminated = _not_terminated;
1448 _privileged_stack_top = NULL;
1449 _array_for_gc = NULL;
1450 _suspend_equivalent = false;
1451 _in_deopt_handler = 0;
1452 _doing_unsafe_access = false;
1453 _stack_guard_state = stack_guard_unused;
1454 (void)const_cast<oop&>(_exception_oop = NULL);
1455 _exception_pc = 0;
1456 _exception_handler_pc = 0;
1457 _is_method_handle_return = 0;
1458 _jvmti_thread_state= NULL;
1459 _should_post_on_exceptions_flag = JNI_FALSE;
1460 _jvmti_get_loaded_classes_closure = NULL;
1461 _interp_only_mode = 0;
1462 _special_runtime_exit_condition = _no_async_condition;
1463 _pending_async_exception = NULL;
1464 _thread_stat = NULL;
1465 _thread_stat = new ThreadStatistics();
1466 _blocked_on_compilation = false;
1467 _jni_active_critical = 0;
1468 _do_not_unlock_if_synchronized = false;
1469 _cached_monitor_info = NULL;
1470 _parker = Parker::Allocate(this) ;
1471
1472 #ifndef PRODUCT
1473 _jmp_ring_index = 0;
1474 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1475 record_jump(NULL, NULL, NULL, 0);
1476 }
1477 #endif /* PRODUCT */
1478
1479 set_thread_profiler(NULL);
1480 if (FlatProfiler::is_active()) {
1481 // This is where we would decide to either give each thread it's own profiler
1482 // or use one global one from FlatProfiler,
1483 // or up to some count of the number of profiled threads, etc.
1484 ThreadProfiler* pp = new ThreadProfiler();
1485 pp->engage();
1486 set_thread_profiler(pp);
1487 }
1488
1489 // Setup safepoint state info for this thread
1490 ThreadSafepointState::create(this);
1491
1492 debug_only(_java_call_counter = 0);
1493
1494 // JVMTI PopFrame support
1495 _popframe_condition = popframe_inactive;
1496 _popframe_preserved_args = NULL;
1497 _popframe_preserved_args_size = 0;
1498
1499 pd_initialize();
1500 }
1501
1502 #if INCLUDE_ALL_GCS
1503 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1504 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1505 #endif // INCLUDE_ALL_GCS
1506
1507 JavaThread::JavaThread(bool is_attaching_via_jni) :
1508 Thread()
1509 #if INCLUDE_ALL_GCS
1510 , _satb_mark_queue(&_satb_mark_queue_set),
1511 _dirty_card_queue(&_dirty_card_queue_set)
1512 #endif // INCLUDE_ALL_GCS
1513 {
1514 initialize();
1515 if (is_attaching_via_jni) {
1516 _jni_attach_state = _attaching_via_jni;
1517 } else {
1518 _jni_attach_state = _not_attaching_via_jni;
1519 }
1520 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1521 }
1522
1523 bool JavaThread::reguard_stack(address cur_sp) {
1524 if (_stack_guard_state != stack_guard_yellow_disabled) {
1525 return true; // Stack already guarded or guard pages not needed.
1526 }
1527
1528 if (register_stack_overflow()) {
1529 // For those architectures which have separate register and
1530 // memory stacks, we must check the register stack to see if
1531 // it has overflowed.
1532 return false;
1533 }
1534
1535 // Java code never executes within the yellow zone: the latter is only
1536 // there to provoke an exception during stack banging. If java code
1537 // is executing there, either StackShadowPages should be larger, or
1538 // some exception code in c1, c2 or the interpreter isn't unwinding
1539 // when it should.
1540 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1541
1542 enable_stack_yellow_zone();
1543 return true;
1544 }
1545
1546 bool JavaThread::reguard_stack(void) {
1547 return reguard_stack(os::current_stack_pointer());
1548 }
1549
1550
1551 void JavaThread::block_if_vm_exited() {
1552 if (_terminated == _vm_exited) {
1553 // _vm_exited is set at safepoint, and Threads_lock is never released
1554 // we will block here forever
1555 Threads_lock->lock_without_safepoint_check();
1556 ShouldNotReachHere();
1557 }
1558 }
1559
1560
1561 // Remove this ifdef when C1 is ported to the compiler interface.
1562 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1563
1564 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1565 Thread()
1566 #if INCLUDE_ALL_GCS
1567 , _satb_mark_queue(&_satb_mark_queue_set),
1568 _dirty_card_queue(&_dirty_card_queue_set)
1569 #endif // INCLUDE_ALL_GCS
1570 {
1571 if (TraceThreadEvents) {
1572 tty->print_cr("creating thread %p", this);
1573 }
1574 initialize();
1575 _jni_attach_state = _not_attaching_via_jni;
1576 set_entry_point(entry_point);
1577 // Create the native thread itself.
1578 // %note runtime_23
1579 os::ThreadType thr_type = os::java_thread;
1580 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1581 os::java_thread;
1582 os::create_thread(this, thr_type, stack_sz);
1583 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1584 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1585 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1586 // the exception consists of creating the exception object & initializing it, initialization
1587 // will leave the VM via a JavaCall and then all locks must be unlocked).
1588 //
1589 // The thread is still suspended when we reach here. Thread must be explicit started
1590 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1591 // by calling Threads:add. The reason why this is not done here, is because the thread
1592 // object must be fully initialized (take a look at JVM_Start)
1593 }
1594
1595 JavaThread::~JavaThread() {
1596 if (TraceThreadEvents) {
1597 tty->print_cr("terminate thread %p", this);
1598 }
1599
1600 // JSR166 -- return the parker to the free list
1601 Parker::Release(_parker);
1602 _parker = NULL ;
1603
1604 // Free any remaining previous UnrollBlock
1605 vframeArray* old_array = vframe_array_last();
1606
1607 if (old_array != NULL) {
1608 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1609 old_array->set_unroll_block(NULL);
1610 delete old_info;
1611 delete old_array;
1612 }
1613
1614 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1615 if (deferred != NULL) {
1616 // This can only happen if thread is destroyed before deoptimization occurs.
1617 assert(deferred->length() != 0, "empty array!");
1618 do {
1619 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1620 deferred->remove_at(0);
1621 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1622 delete dlv;
1623 } while (deferred->length() != 0);
1624 delete deferred;
1625 }
1626
1627 // All Java related clean up happens in exit
1628 ThreadSafepointState::destroy(this);
1629 if (_thread_profiler != NULL) delete _thread_profiler;
1630 if (_thread_stat != NULL) delete _thread_stat;
1631 }
1632
1633
1634 // The first routine called by a new Java thread
1635 void JavaThread::run() {
1636 // initialize thread-local alloc buffer related fields
1637 this->initialize_tlab();
1638
1639 // used to test validitity of stack trace backs
1640 this->record_base_of_stack_pointer();
1641
1642 // Record real stack base and size.
1643 this->record_stack_base_and_size();
1644
1645 // Initialize thread local storage; set before calling MutexLocker
1646 this->initialize_thread_local_storage();
1647
1648 this->create_stack_guard_pages();
1649
1650 this->cache_global_variables();
1651
1652 // Thread is now sufficient initialized to be handled by the safepoint code as being
1653 // in the VM. Change thread state from _thread_new to _thread_in_vm
1654 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1655
1656 assert(JavaThread::current() == this, "sanity check");
1657 assert(!Thread::current()->owns_locks(), "sanity check");
1658
1659 DTRACE_THREAD_PROBE(start, this);
1660
1661 // This operation might block. We call that after all safepoint checks for a new thread has
1662 // been completed.
1663 this->set_active_handles(JNIHandleBlock::allocate_block());
1664
1665 if (JvmtiExport::should_post_thread_life()) {
1666 JvmtiExport::post_thread_start(this);
1667 }
1668
1669 EventThreadStart event;
1670 if (event.should_commit()) {
1671 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1672 event.commit();
1673 }
1674
1675 // We call another function to do the rest so we are sure that the stack addresses used
1676 // from there will be lower than the stack base just computed
1677 thread_main_inner();
1678
1679 // Note, thread is no longer valid at this point!
1680 }
1681
1682
1683 void JavaThread::thread_main_inner() {
1684 assert(JavaThread::current() == this, "sanity check");
1685 assert(this->threadObj() != NULL, "just checking");
1686
1687 // Execute thread entry point unless this thread has a pending exception
1688 // or has been stopped before starting.
1689 // Note: Due to JVM_StopThread we can have pending exceptions already!
1690 if (!this->has_pending_exception() &&
1691 !java_lang_Thread::is_stillborn(this->threadObj())) {
1692 {
1693 ResourceMark rm(this);
1694 this->set_native_thread_name(this->get_thread_name());
1695 }
1696 HandleMark hm(this);
1697 this->entry_point()(this, this);
1698 }
1699
1700 DTRACE_THREAD_PROBE(stop, this);
1701
1702 this->exit(false);
1703 delete this;
1704 }
1705
1706
1707 static void ensure_join(JavaThread* thread) {
1708 // We do not need to grap the Threads_lock, since we are operating on ourself.
1709 Handle threadObj(thread, thread->threadObj());
1710 assert(threadObj.not_null(), "java thread object must exist");
1711 ObjectLocker lock(threadObj, thread);
1712 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1713 thread->clear_pending_exception();
1714 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1715 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1716 // Clear the native thread instance - this makes isAlive return false and allows the join()
1717 // to complete once we've done the notify_all below
1718 java_lang_Thread::set_thread(threadObj(), NULL);
1719 lock.notify_all(thread);
1720 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1721 thread->clear_pending_exception();
1722 }
1723
1724
1725 // For any new cleanup additions, please check to see if they need to be applied to
1726 // cleanup_failed_attach_current_thread as well.
1727 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1728 assert(this == JavaThread::current(), "thread consistency check");
1729
1730 HandleMark hm(this);
1731 Handle uncaught_exception(this, this->pending_exception());
1732 this->clear_pending_exception();
1733 Handle threadObj(this, this->threadObj());
1734 assert(threadObj.not_null(), "Java thread object should be created");
1735
1736 if (get_thread_profiler() != NULL) {
1737 get_thread_profiler()->disengage();
1738 ResourceMark rm;
1739 get_thread_profiler()->print(get_thread_name());
1740 }
1741
1742
1743 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1744 {
1745 EXCEPTION_MARK;
1746
1747 CLEAR_PENDING_EXCEPTION;
1748 }
1749 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1750 // has to be fixed by a runtime query method
1751 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1752 // JSR-166: change call from from ThreadGroup.uncaughtException to
1753 // java.lang.Thread.dispatchUncaughtException
1754 if (uncaught_exception.not_null()) {
1755 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1756 {
1757 EXCEPTION_MARK;
1758 // Check if the method Thread.dispatchUncaughtException() exists. If so
1759 // call it. Otherwise we have an older library without the JSR-166 changes,
1760 // so call ThreadGroup.uncaughtException()
1761 KlassHandle recvrKlass(THREAD, threadObj->klass());
1762 CallInfo callinfo;
1763 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1764 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1765 vmSymbols::dispatchUncaughtException_name(),
1766 vmSymbols::throwable_void_signature(),
1767 KlassHandle(), false, false, THREAD);
1768 CLEAR_PENDING_EXCEPTION;
1769 methodHandle method = callinfo.selected_method();
1770 if (method.not_null()) {
1771 JavaValue result(T_VOID);
1772 JavaCalls::call_virtual(&result,
1773 threadObj, thread_klass,
1774 vmSymbols::dispatchUncaughtException_name(),
1775 vmSymbols::throwable_void_signature(),
1776 uncaught_exception,
1777 THREAD);
1778 } else {
1779 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1780 JavaValue result(T_VOID);
1781 JavaCalls::call_virtual(&result,
1782 group, thread_group,
1783 vmSymbols::uncaughtException_name(),
1784 vmSymbols::thread_throwable_void_signature(),
1785 threadObj, // Arg 1
1786 uncaught_exception, // Arg 2
1787 THREAD);
1788 }
1789 if (HAS_PENDING_EXCEPTION) {
1790 ResourceMark rm(this);
1791 jio_fprintf(defaultStream::error_stream(),
1792 "\nException: %s thrown from the UncaughtExceptionHandler"
1793 " in thread \"%s\"\n",
1794 pending_exception()->klass()->external_name(),
1795 get_thread_name());
1796 CLEAR_PENDING_EXCEPTION;
1797 }
1798 }
1799 }
1800
1801 // Called before the java thread exit since we want to read info
1802 // from java_lang_Thread object
1803 EventThreadEnd event;
1804 if (event.should_commit()) {
1805 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1806 event.commit();
1807 }
1808
1809 // Call after last event on thread
1810 EVENT_THREAD_EXIT(this);
1811
1812 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1813 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1814 // is deprecated anyhow.
1815 if (!is_Compiler_thread()) {
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 // notify JVMTI
1830 if (JvmtiExport::should_post_thread_life()) {
1831 JvmtiExport::post_thread_end(this);
1832 }
1833
1834 // We have notified the agents that we are exiting, before we go on,
1835 // we must check for a pending external suspend request and honor it
1836 // in order to not surprise the thread that made the suspend request.
1837 while (true) {
1838 {
1839 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1840 if (!is_external_suspend()) {
1841 set_terminated(_thread_exiting);
1842 ThreadService::current_thread_exiting(this);
1843 break;
1844 }
1845 // Implied else:
1846 // Things get a little tricky here. We have a pending external
1847 // suspend request, but we are holding the SR_lock so we
1848 // can't just self-suspend. So we temporarily drop the lock
1849 // and then self-suspend.
1850 }
1851
1852 ThreadBlockInVM tbivm(this);
1853 java_suspend_self();
1854
1855 // We're done with this suspend request, but we have to loop around
1856 // and check again. Eventually we will get SR_lock without a pending
1857 // external suspend request and will be able to mark ourselves as
1858 // exiting.
1859 }
1860 // no more external suspends are allowed at this point
1861 } else {
1862 // before_exit() has already posted JVMTI THREAD_END events
1863 }
1864
1865 // Notify waiters on thread object. This has to be done after exit() is called
1866 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1867 // group should have the destroyed bit set before waiters are notified).
1868 ensure_join(this);
1869 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1870
1871 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1872 // held by this thread must be released. A detach operation must only
1873 // get here if there are no Java frames on the stack. Therefore, any
1874 // owned monitors at this point MUST be JNI-acquired monitors which are
1875 // pre-inflated and in the monitor cache.
1876 //
1877 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1878 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1879 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1880 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1881 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1882 }
1883
1884 // These things needs to be done while we are still a Java Thread. Make sure that thread
1885 // is in a consistent state, in case GC happens
1886 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1887
1888 if (active_handles() != NULL) {
1889 JNIHandleBlock* block = active_handles();
1890 set_active_handles(NULL);
1891 JNIHandleBlock::release_block(block);
1892 }
1893
1894 if (free_handle_block() != NULL) {
1895 JNIHandleBlock* block = free_handle_block();
1896 set_free_handle_block(NULL);
1897 JNIHandleBlock::release_block(block);
1898 }
1899
1900 // These have to be removed while this is still a valid thread.
1901 remove_stack_guard_pages();
1902
1903 if (UseTLAB) {
1904 tlab().make_parsable(true); // retire TLAB
1905 }
1906
1907 if (JvmtiEnv::environments_might_exist()) {
1908 JvmtiExport::cleanup_thread(this);
1909 }
1910
1911 // We must flush any deferred card marks before removing a thread from
1912 // the list of active threads.
1913 Universe::heap()->flush_deferred_store_barrier(this);
1914 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1915
1916 #if INCLUDE_ALL_GCS
1917 // We must flush the G1-related buffers before removing a thread
1918 // from the list of active threads. We must do this after any deferred
1919 // card marks have been flushed (above) so that any entries that are
1920 // added to the thread's dirty card queue as a result are not lost.
1921 if (UseG1GC) {
1922 flush_barrier_queues();
1923 }
1924 #endif // INCLUDE_ALL_GCS
1925
1926 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1927 Threads::remove(this);
1928 }
1929
1930 #if INCLUDE_ALL_GCS
1931 // Flush G1-related queues.
1932 void JavaThread::flush_barrier_queues() {
1933 satb_mark_queue().flush();
1934 dirty_card_queue().flush();
1935 }
1936
1937 void JavaThread::initialize_queues() {
1938 assert(!SafepointSynchronize::is_at_safepoint(),
1939 "we should not be at a safepoint");
1940
1941 ObjPtrQueue& satb_queue = satb_mark_queue();
1942 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1943 // The SATB queue should have been constructed with its active
1944 // field set to false.
1945 assert(!satb_queue.is_active(), "SATB queue should not be active");
1946 assert(satb_queue.is_empty(), "SATB queue should be empty");
1947 // If we are creating the thread during a marking cycle, we should
1948 // set the active field of the SATB queue to true.
1949 if (satb_queue_set.is_active()) {
1950 satb_queue.set_active(true);
1951 }
1952
1953 DirtyCardQueue& dirty_queue = dirty_card_queue();
1954 // The dirty card queue should have been constructed with its
1955 // active field set to true.
1956 assert(dirty_queue.is_active(), "dirty card queue should be active");
1957 }
1958 #endif // INCLUDE_ALL_GCS
1959
1960 void JavaThread::cleanup_failed_attach_current_thread() {
1961 if (get_thread_profiler() != NULL) {
1962 get_thread_profiler()->disengage();
1963 ResourceMark rm;
1964 get_thread_profiler()->print(get_thread_name());
1965 }
1966
1967 if (active_handles() != NULL) {
1968 JNIHandleBlock* block = active_handles();
1969 set_active_handles(NULL);
1970 JNIHandleBlock::release_block(block);
1971 }
1972
1973 if (free_handle_block() != NULL) {
1974 JNIHandleBlock* block = free_handle_block();
1975 set_free_handle_block(NULL);
1976 JNIHandleBlock::release_block(block);
1977 }
1978
1979 // These have to be removed while this is still a valid thread.
1980 remove_stack_guard_pages();
1981
1982 if (UseTLAB) {
1983 tlab().make_parsable(true); // retire TLAB, if any
1984 }
1985
1986 #if INCLUDE_ALL_GCS
1987 if (UseG1GC) {
1988 flush_barrier_queues();
1989 }
1990 #endif // INCLUDE_ALL_GCS
1991
1992 Threads::remove(this);
1993 delete this;
1994 }
1995
1996
1997
1998
1999 JavaThread* JavaThread::active() {
2000 Thread* thread = ThreadLocalStorage::thread();
2001 assert(thread != NULL, "just checking");
2002 if (thread->is_Java_thread()) {
2003 return (JavaThread*) thread;
2004 } else {
2005 assert(thread->is_VM_thread(), "this must be a vm thread");
2006 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2007 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2008 assert(ret->is_Java_thread(), "must be a Java thread");
2009 return ret;
2010 }
2011 }
2012
2013 bool JavaThread::is_lock_owned(address adr) const {
2014 if (Thread::is_lock_owned(adr)) return true;
2015
2016 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2017 if (chunk->contains(adr)) return true;
2018 }
2019
2020 return false;
2021 }
2022
2023
2024 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2025 chunk->set_next(monitor_chunks());
2026 set_monitor_chunks(chunk);
2027 }
2028
2029 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2030 guarantee(monitor_chunks() != NULL, "must be non empty");
2031 if (monitor_chunks() == chunk) {
2032 set_monitor_chunks(chunk->next());
2033 } else {
2034 MonitorChunk* prev = monitor_chunks();
2035 while (prev->next() != chunk) prev = prev->next();
2036 prev->set_next(chunk->next());
2037 }
2038 }
2039
2040 // JVM support.
2041
2042 // Note: this function shouldn't block if it's called in
2043 // _thread_in_native_trans state (such as from
2044 // check_special_condition_for_native_trans()).
2045 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2046
2047 if (has_last_Java_frame() && has_async_condition()) {
2048 // If we are at a polling page safepoint (not a poll return)
2049 // then we must defer async exception because live registers
2050 // will be clobbered by the exception path. Poll return is
2051 // ok because the call we a returning from already collides
2052 // with exception handling registers and so there is no issue.
2053 // (The exception handling path kills call result registers but
2054 // this is ok since the exception kills the result anyway).
2055
2056 if (is_at_poll_safepoint()) {
2057 // if the code we are returning to has deoptimized we must defer
2058 // the exception otherwise live registers get clobbered on the
2059 // exception path before deoptimization is able to retrieve them.
2060 //
2061 RegisterMap map(this, false);
2062 frame caller_fr = last_frame().sender(&map);
2063 assert(caller_fr.is_compiled_frame(), "what?");
2064 if (caller_fr.is_deoptimized_frame()) {
2065 if (TraceExceptions) {
2066 ResourceMark rm;
2067 tty->print_cr("deferred async exception at compiled safepoint");
2068 }
2069 return;
2070 }
2071 }
2072 }
2073
2074 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2075 if (condition == _no_async_condition) {
2076 // Conditions have changed since has_special_runtime_exit_condition()
2077 // was called:
2078 // - if we were here only because of an external suspend request,
2079 // then that was taken care of above (or cancelled) so we are done
2080 // - if we were here because of another async request, then it has
2081 // been cleared between the has_special_runtime_exit_condition()
2082 // and now so again we are done
2083 return;
2084 }
2085
2086 // Check for pending async. exception
2087 if (_pending_async_exception != NULL) {
2088 // Only overwrite an already pending exception, if it is not a threadDeath.
2089 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2090
2091 // We cannot call Exceptions::_throw(...) here because we cannot block
2092 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2093
2094 if (TraceExceptions) {
2095 ResourceMark rm;
2096 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2097 if (has_last_Java_frame() ) {
2098 frame f = last_frame();
2099 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2100 }
2101 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2102 }
2103 _pending_async_exception = NULL;
2104 clear_has_async_exception();
2105 }
2106 }
2107
2108 if (check_unsafe_error &&
2109 condition == _async_unsafe_access_error && !has_pending_exception()) {
2110 condition = _no_async_condition; // done
2111 switch (thread_state()) {
2112 case _thread_in_vm:
2113 {
2114 JavaThread* THREAD = this;
2115 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2116 }
2117 case _thread_in_native:
2118 {
2119 ThreadInVMfromNative tiv(this);
2120 JavaThread* THREAD = this;
2121 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2122 }
2123 case _thread_in_Java:
2124 {
2125 ThreadInVMfromJava tiv(this);
2126 JavaThread* THREAD = this;
2127 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2128 }
2129 default:
2130 ShouldNotReachHere();
2131 }
2132 }
2133
2134 assert(condition == _no_async_condition || has_pending_exception() ||
2135 (!check_unsafe_error && condition == _async_unsafe_access_error),
2136 "must have handled the async condition, if no exception");
2137 }
2138
2139 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2140 //
2141 // Check for pending external suspend. Internal suspend requests do
2142 // not use handle_special_runtime_exit_condition().
2143 // If JNIEnv proxies are allowed, don't self-suspend if the target
2144 // thread is not the current thread. In older versions of jdbx, jdbx
2145 // threads could call into the VM with another thread's JNIEnv so we
2146 // can be here operating on behalf of a suspended thread (4432884).
2147 bool do_self_suspend = is_external_suspend_with_lock();
2148 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2149 //
2150 // Because thread is external suspended the safepoint code will count
2151 // thread as at a safepoint. This can be odd because we can be here
2152 // as _thread_in_Java which would normally transition to _thread_blocked
2153 // at a safepoint. We would like to mark the thread as _thread_blocked
2154 // before calling java_suspend_self like all other callers of it but
2155 // we must then observe proper safepoint protocol. (We can't leave
2156 // _thread_blocked with a safepoint in progress). However we can be
2157 // here as _thread_in_native_trans so we can't use a normal transition
2158 // constructor/destructor pair because they assert on that type of
2159 // transition. We could do something like:
2160 //
2161 // JavaThreadState state = thread_state();
2162 // set_thread_state(_thread_in_vm);
2163 // {
2164 // ThreadBlockInVM tbivm(this);
2165 // java_suspend_self()
2166 // }
2167 // set_thread_state(_thread_in_vm_trans);
2168 // if (safepoint) block;
2169 // set_thread_state(state);
2170 //
2171 // but that is pretty messy. Instead we just go with the way the
2172 // code has worked before and note that this is the only path to
2173 // java_suspend_self that doesn't put the thread in _thread_blocked
2174 // mode.
2175
2176 frame_anchor()->make_walkable(this);
2177 java_suspend_self();
2178
2179 // We might be here for reasons in addition to the self-suspend request
2180 // so check for other async requests.
2181 }
2182
2183 if (check_asyncs) {
2184 check_and_handle_async_exceptions();
2185 }
2186 }
2187
2188 void JavaThread::send_thread_stop(oop java_throwable) {
2189 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2190 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2191 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2192
2193 // Do not throw asynchronous exceptions against the compiler thread
2194 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2195 if (is_Compiler_thread()) return;
2196
2197 {
2198 // Actually throw the Throwable against the target Thread - however
2199 // only if there is no thread death exception installed already.
2200 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2201 // If the topmost frame is a runtime stub, then we are calling into
2202 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2203 // must deoptimize the caller before continuing, as the compiled exception handler table
2204 // may not be valid
2205 if (has_last_Java_frame()) {
2206 frame f = last_frame();
2207 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2208 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2209 RegisterMap reg_map(this, UseBiasedLocking);
2210 frame compiled_frame = f.sender(®_map);
2211 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2212 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2213 }
2214 }
2215 }
2216
2217 // Set async. pending exception in thread.
2218 set_pending_async_exception(java_throwable);
2219
2220 if (TraceExceptions) {
2221 ResourceMark rm;
2222 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2223 }
2224 // for AbortVMOnException flag
2225 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2226 }
2227 }
2228
2229
2230 // Interrupt thread so it will wake up from a potential wait()
2231 Thread::interrupt(this);
2232 }
2233
2234 // External suspension mechanism.
2235 //
2236 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2237 // to any VM_locks and it is at a transition
2238 // Self-suspension will happen on the transition out of the vm.
2239 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2240 //
2241 // Guarantees on return:
2242 // + Target thread will not execute any new bytecode (that's why we need to
2243 // force a safepoint)
2244 // + Target thread will not enter any new monitors
2245 //
2246 void JavaThread::java_suspend() {
2247 { MutexLocker mu(Threads_lock);
2248 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2249 return;
2250 }
2251 }
2252
2253 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2254 if (!is_external_suspend()) {
2255 // a racing resume has cancelled us; bail out now
2256 return;
2257 }
2258
2259 // suspend is done
2260 uint32_t debug_bits = 0;
2261 // Warning: is_ext_suspend_completed() may temporarily drop the
2262 // SR_lock to allow the thread to reach a stable thread state if
2263 // it is currently in a transient thread state.
2264 if (is_ext_suspend_completed(false /* !called_by_wait */,
2265 SuspendRetryDelay, &debug_bits) ) {
2266 return;
2267 }
2268 }
2269
2270 VM_ForceSafepoint vm_suspend;
2271 VMThread::execute(&vm_suspend);
2272 }
2273
2274 // Part II of external suspension.
2275 // A JavaThread self suspends when it detects a pending external suspend
2276 // request. This is usually on transitions. It is also done in places
2277 // where continuing to the next transition would surprise the caller,
2278 // e.g., monitor entry.
2279 //
2280 // Returns the number of times that the thread self-suspended.
2281 //
2282 // Note: DO NOT call java_suspend_self() when you just want to block current
2283 // thread. java_suspend_self() is the second stage of cooperative
2284 // suspension for external suspend requests and should only be used
2285 // to complete an external suspend request.
2286 //
2287 int JavaThread::java_suspend_self() {
2288 int ret = 0;
2289
2290 // we are in the process of exiting so don't suspend
2291 if (is_exiting()) {
2292 clear_external_suspend();
2293 return ret;
2294 }
2295
2296 assert(_anchor.walkable() ||
2297 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2298 "must have walkable stack");
2299
2300 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2301
2302 assert(!this->is_ext_suspended(),
2303 "a thread trying to self-suspend should not already be suspended");
2304
2305 if (this->is_suspend_equivalent()) {
2306 // If we are self-suspending as a result of the lifting of a
2307 // suspend equivalent condition, then the suspend_equivalent
2308 // flag is not cleared until we set the ext_suspended flag so
2309 // that wait_for_ext_suspend_completion() returns consistent
2310 // results.
2311 this->clear_suspend_equivalent();
2312 }
2313
2314 // A racing resume may have cancelled us before we grabbed SR_lock
2315 // above. Or another external suspend request could be waiting for us
2316 // by the time we return from SR_lock()->wait(). The thread
2317 // that requested the suspension may already be trying to walk our
2318 // stack and if we return now, we can change the stack out from under
2319 // it. This would be a "bad thing (TM)" and cause the stack walker
2320 // to crash. We stay self-suspended until there are no more pending
2321 // external suspend requests.
2322 while (is_external_suspend()) {
2323 ret++;
2324 this->set_ext_suspended();
2325
2326 // _ext_suspended flag is cleared by java_resume()
2327 while (is_ext_suspended()) {
2328 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2329 }
2330 }
2331
2332 return ret;
2333 }
2334
2335 #ifdef ASSERT
2336 // verify the JavaThread has not yet been published in the Threads::list, and
2337 // hence doesn't need protection from concurrent access at this stage
2338 void JavaThread::verify_not_published() {
2339 if (!Threads_lock->owned_by_self()) {
2340 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2341 assert( !Threads::includes(this),
2342 "java thread shouldn't have been published yet!");
2343 }
2344 else {
2345 assert( !Threads::includes(this),
2346 "java thread shouldn't have been published yet!");
2347 }
2348 }
2349 #endif
2350
2351 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2352 // progress or when _suspend_flags is non-zero.
2353 // Current thread needs to self-suspend if there is a suspend request and/or
2354 // block if a safepoint is in progress.
2355 // Async exception ISN'T checked.
2356 // Note only the ThreadInVMfromNative transition can call this function
2357 // directly and when thread state is _thread_in_native_trans
2358 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2359 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2360
2361 JavaThread *curJT = JavaThread::current();
2362 bool do_self_suspend = thread->is_external_suspend();
2363
2364 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2365
2366 // If JNIEnv proxies are allowed, don't self-suspend if the target
2367 // thread is not the current thread. In older versions of jdbx, jdbx
2368 // threads could call into the VM with another thread's JNIEnv so we
2369 // can be here operating on behalf of a suspended thread (4432884).
2370 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2371 JavaThreadState state = thread->thread_state();
2372
2373 // We mark this thread_blocked state as a suspend-equivalent so
2374 // that a caller to is_ext_suspend_completed() won't be confused.
2375 // The suspend-equivalent state is cleared by java_suspend_self().
2376 thread->set_suspend_equivalent();
2377
2378 // If the safepoint code sees the _thread_in_native_trans state, it will
2379 // wait until the thread changes to other thread state. There is no
2380 // guarantee on how soon we can obtain the SR_lock and complete the
2381 // self-suspend request. It would be a bad idea to let safepoint wait for
2382 // too long. Temporarily change the state to _thread_blocked to
2383 // let the VM thread know that this thread is ready for GC. The problem
2384 // of changing thread state is that safepoint could happen just after
2385 // java_suspend_self() returns after being resumed, and VM thread will
2386 // see the _thread_blocked state. We must check for safepoint
2387 // after restoring the state and make sure we won't leave while a safepoint
2388 // is in progress.
2389 thread->set_thread_state(_thread_blocked);
2390 thread->java_suspend_self();
2391 thread->set_thread_state(state);
2392 // Make sure new state is seen by VM thread
2393 if (os::is_MP()) {
2394 if (UseMembar) {
2395 // Force a fence between the write above and read below
2396 OrderAccess::fence();
2397 } else {
2398 // Must use this rather than serialization page in particular on Windows
2399 InterfaceSupport::serialize_memory(thread);
2400 }
2401 }
2402 }
2403
2404 if (SafepointSynchronize::do_call_back()) {
2405 // If we are safepointing, then block the caller which may not be
2406 // the same as the target thread (see above).
2407 SafepointSynchronize::block(curJT);
2408 }
2409
2410 if (thread->is_deopt_suspend()) {
2411 thread->clear_deopt_suspend();
2412 RegisterMap map(thread, false);
2413 frame f = thread->last_frame();
2414 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2415 f = f.sender(&map);
2416 }
2417 if (f.id() == thread->must_deopt_id()) {
2418 thread->clear_must_deopt_id();
2419 f.deoptimize(thread);
2420 } else {
2421 fatal("missed deoptimization!");
2422 }
2423 }
2424 }
2425
2426 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2427 // progress or when _suspend_flags is non-zero.
2428 // Current thread needs to self-suspend if there is a suspend request and/or
2429 // block if a safepoint is in progress.
2430 // Also check for pending async exception (not including unsafe access error).
2431 // Note only the native==>VM/Java barriers can call this function and when
2432 // thread state is _thread_in_native_trans.
2433 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2434 check_safepoint_and_suspend_for_native_trans(thread);
2435
2436 if (thread->has_async_exception()) {
2437 // We are in _thread_in_native_trans state, don't handle unsafe
2438 // access error since that may block.
2439 thread->check_and_handle_async_exceptions(false);
2440 }
2441 }
2442
2443 // This is a variant of the normal
2444 // check_special_condition_for_native_trans with slightly different
2445 // semantics for use by critical native wrappers. It does all the
2446 // normal checks but also performs the transition back into
2447 // thread_in_Java state. This is required so that critical natives
2448 // can potentially block and perform a GC if they are the last thread
2449 // exiting the GC_locker.
2450 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2451 check_special_condition_for_native_trans(thread);
2452
2453 // Finish the transition
2454 thread->set_thread_state(_thread_in_Java);
2455
2456 if (thread->do_critical_native_unlock()) {
2457 ThreadInVMfromJavaNoAsyncException tiv(thread);
2458 GC_locker::unlock_critical(thread);
2459 thread->clear_critical_native_unlock();
2460 }
2461 }
2462
2463 // We need to guarantee the Threads_lock here, since resumes are not
2464 // allowed during safepoint synchronization
2465 // Can only resume from an external suspension
2466 void JavaThread::java_resume() {
2467 assert_locked_or_safepoint(Threads_lock);
2468
2469 // Sanity check: thread is gone, has started exiting or the thread
2470 // was not externally suspended.
2471 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2472 return;
2473 }
2474
2475 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2476
2477 clear_external_suspend();
2478
2479 if (is_ext_suspended()) {
2480 clear_ext_suspended();
2481 SR_lock()->notify_all();
2482 }
2483 }
2484
2485 void JavaThread::create_stack_guard_pages() {
2486 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2487 address low_addr = stack_base() - stack_size();
2488 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2489
2490 int allocate = os::allocate_stack_guard_pages();
2491 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2492
2493 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2494 warning("Attempt to allocate stack guard pages failed.");
2495 return;
2496 }
2497
2498 if (os::guard_memory((char *) low_addr, len)) {
2499 _stack_guard_state = stack_guard_enabled;
2500 } else {
2501 warning("Attempt to protect stack guard pages failed.");
2502 if (os::uncommit_memory((char *) low_addr, len)) {
2503 warning("Attempt to deallocate stack guard pages failed.");
2504 }
2505 }
2506 }
2507
2508 void JavaThread::remove_stack_guard_pages() {
2509 assert(Thread::current() == this, "from different thread");
2510 if (_stack_guard_state == stack_guard_unused) return;
2511 address low_addr = stack_base() - stack_size();
2512 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2513
2514 if (os::allocate_stack_guard_pages()) {
2515 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2516 _stack_guard_state = stack_guard_unused;
2517 } else {
2518 warning("Attempt to deallocate stack guard pages failed.");
2519 }
2520 } else {
2521 if (_stack_guard_state == stack_guard_unused) return;
2522 if (os::unguard_memory((char *) low_addr, len)) {
2523 _stack_guard_state = stack_guard_unused;
2524 } else {
2525 warning("Attempt to unprotect stack guard pages failed.");
2526 }
2527 }
2528 }
2529
2530 void JavaThread::enable_stack_yellow_zone() {
2531 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2532 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2533
2534 // The base notation is from the stacks point of view, growing downward.
2535 // We need to adjust it to work correctly with guard_memory()
2536 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2537
2538 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2539 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2540
2541 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2542 _stack_guard_state = stack_guard_enabled;
2543 } else {
2544 warning("Attempt to guard stack yellow zone failed.");
2545 }
2546 enable_register_stack_guard();
2547 }
2548
2549 void JavaThread::disable_stack_yellow_zone() {
2550 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2551 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2552
2553 // Simply return if called for a thread that does not use guard pages.
2554 if (_stack_guard_state == stack_guard_unused) return;
2555
2556 // The base notation is from the stacks point of view, growing downward.
2557 // We need to adjust it to work correctly with guard_memory()
2558 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2559
2560 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2561 _stack_guard_state = stack_guard_yellow_disabled;
2562 } else {
2563 warning("Attempt to unguard stack yellow zone failed.");
2564 }
2565 disable_register_stack_guard();
2566 }
2567
2568 void JavaThread::enable_stack_red_zone() {
2569 // The base notation is from the stacks point of view, growing downward.
2570 // We need to adjust it to work correctly with guard_memory()
2571 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2572 address base = stack_red_zone_base() - stack_red_zone_size();
2573
2574 guarantee(base < stack_base(),"Error calculating stack red zone");
2575 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2576
2577 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2578 warning("Attempt to guard stack red zone failed.");
2579 }
2580 }
2581
2582 void JavaThread::disable_stack_red_zone() {
2583 // The base notation is from the stacks point of view, growing downward.
2584 // We need to adjust it to work correctly with guard_memory()
2585 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2586 address base = stack_red_zone_base() - stack_red_zone_size();
2587 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2588 warning("Attempt to unguard stack red zone failed.");
2589 }
2590 }
2591
2592 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2593 // ignore is there is no stack
2594 if (!has_last_Java_frame()) return;
2595 // traverse the stack frames. Starts from top frame.
2596 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2597 frame* fr = fst.current();
2598 f(fr, fst.register_map());
2599 }
2600 }
2601
2602
2603 #ifndef PRODUCT
2604 // Deoptimization
2605 // Function for testing deoptimization
2606 void JavaThread::deoptimize() {
2607 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2608 StackFrameStream fst(this, UseBiasedLocking);
2609 bool deopt = false; // Dump stack only if a deopt actually happens.
2610 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2611 // Iterate over all frames in the thread and deoptimize
2612 for(; !fst.is_done(); fst.next()) {
2613 if(fst.current()->can_be_deoptimized()) {
2614
2615 if (only_at) {
2616 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2617 // consists of comma or carriage return separated numbers so
2618 // search for the current bci in that string.
2619 address pc = fst.current()->pc();
2620 nmethod* nm = (nmethod*) fst.current()->cb();
2621 ScopeDesc* sd = nm->scope_desc_at( pc);
2622 char buffer[8];
2623 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2624 size_t len = strlen(buffer);
2625 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2626 while (found != NULL) {
2627 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2628 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2629 // Check that the bci found is bracketed by terminators.
2630 break;
2631 }
2632 found = strstr(found + 1, buffer);
2633 }
2634 if (!found) {
2635 continue;
2636 }
2637 }
2638
2639 if (DebugDeoptimization && !deopt) {
2640 deopt = true; // One-time only print before deopt
2641 tty->print_cr("[BEFORE Deoptimization]");
2642 trace_frames();
2643 trace_stack();
2644 }
2645 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2646 }
2647 }
2648
2649 if (DebugDeoptimization && deopt) {
2650 tty->print_cr("[AFTER Deoptimization]");
2651 trace_frames();
2652 }
2653 }
2654
2655
2656 // Make zombies
2657 void JavaThread::make_zombies() {
2658 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2659 if (fst.current()->can_be_deoptimized()) {
2660 // it is a Java nmethod
2661 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2662 nm->make_not_entrant();
2663 }
2664 }
2665 }
2666 #endif // PRODUCT
2667
2668
2669 void JavaThread::deoptimized_wrt_marked_nmethods() {
2670 if (!has_last_Java_frame()) return;
2671 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2672 StackFrameStream fst(this, UseBiasedLocking);
2673 for(; !fst.is_done(); fst.next()) {
2674 if (fst.current()->should_be_deoptimized()) {
2675 if (LogCompilation && xtty != NULL) {
2676 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2677 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2678 this->name(), nm != NULL ? nm->compile_id() : -1);
2679 }
2680
2681 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2682 }
2683 }
2684 }
2685
2686
2687 // GC support
2688 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2689
2690 void JavaThread::gc_epilogue() {
2691 frames_do(frame_gc_epilogue);
2692 }
2693
2694
2695 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2696
2697 void JavaThread::gc_prologue() {
2698 frames_do(frame_gc_prologue);
2699 }
2700
2701 // If the caller is a NamedThread, then remember, in the current scope,
2702 // the given JavaThread in its _processed_thread field.
2703 class RememberProcessedThread: public StackObj {
2704 NamedThread* _cur_thr;
2705 public:
2706 RememberProcessedThread(JavaThread* jthr) {
2707 Thread* thread = Thread::current();
2708 if (thread->is_Named_thread()) {
2709 _cur_thr = (NamedThread *)thread;
2710 _cur_thr->set_processed_thread(jthr);
2711 } else {
2712 _cur_thr = NULL;
2713 }
2714 }
2715
2716 ~RememberProcessedThread() {
2717 if (_cur_thr) {
2718 _cur_thr->set_processed_thread(NULL);
2719 }
2720 }
2721 };
2722
2723 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2724 // Verify that the deferred card marks have been flushed.
2725 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2726
2727 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2728 // since there may be more than one thread using each ThreadProfiler.
2729
2730 // Traverse the GCHandles
2731 Thread::oops_do(f, cld_f, cf);
2732
2733 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2734 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2735
2736 if (has_last_Java_frame()) {
2737 // Record JavaThread to GC thread
2738 RememberProcessedThread rpt(this);
2739
2740 // Traverse the privileged stack
2741 if (_privileged_stack_top != NULL) {
2742 _privileged_stack_top->oops_do(f);
2743 }
2744
2745 // traverse the registered growable array
2746 if (_array_for_gc != NULL) {
2747 for (int index = 0; index < _array_for_gc->length(); index++) {
2748 f->do_oop(_array_for_gc->adr_at(index));
2749 }
2750 }
2751
2752 // Traverse the monitor chunks
2753 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2754 chunk->oops_do(f);
2755 }
2756
2757 // Traverse the execution stack
2758 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2759 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2760 }
2761 }
2762
2763 // callee_target is never live across a gc point so NULL it here should
2764 // it still contain a methdOop.
2765
2766 set_callee_target(NULL);
2767
2768 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2769 // If we have deferred set_locals there might be oops waiting to be
2770 // written
2771 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2772 if (list != NULL) {
2773 for (int i = 0; i < list->length(); i++) {
2774 list->at(i)->oops_do(f);
2775 }
2776 }
2777
2778 // Traverse instance variables at the end since the GC may be moving things
2779 // around using this function
2780 f->do_oop((oop*) &_threadObj);
2781 f->do_oop((oop*) &_vm_result);
2782 f->do_oop((oop*) &_exception_oop);
2783 f->do_oop((oop*) &_pending_async_exception);
2784
2785 if (jvmti_thread_state() != NULL) {
2786 jvmti_thread_state()->oops_do(f);
2787 }
2788 }
2789
2790 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2791 Thread::nmethods_do(cf); // (super method is a no-op)
2792
2793 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2794 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2795
2796 if (has_last_Java_frame()) {
2797 // Traverse the execution stack
2798 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2799 fst.current()->nmethods_do(cf);
2800 }
2801 }
2802 }
2803
2804 void JavaThread::metadata_do(void f(Metadata*)) {
2805 Thread::metadata_do(f);
2806 if (has_last_Java_frame()) {
2807 // Traverse the execution stack to call f() on the methods in the stack
2808 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2809 fst.current()->metadata_do(f);
2810 }
2811 } else if (is_Compiler_thread()) {
2812 // need to walk ciMetadata in current compile tasks to keep alive.
2813 CompilerThread* ct = (CompilerThread*)this;
2814 if (ct->env() != NULL) {
2815 ct->env()->metadata_do(f);
2816 }
2817 }
2818 }
2819
2820 // Printing
2821 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2822 switch (_thread_state) {
2823 case _thread_uninitialized: return "_thread_uninitialized";
2824 case _thread_new: return "_thread_new";
2825 case _thread_new_trans: return "_thread_new_trans";
2826 case _thread_in_native: return "_thread_in_native";
2827 case _thread_in_native_trans: return "_thread_in_native_trans";
2828 case _thread_in_vm: return "_thread_in_vm";
2829 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2830 case _thread_in_Java: return "_thread_in_Java";
2831 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2832 case _thread_blocked: return "_thread_blocked";
2833 case _thread_blocked_trans: return "_thread_blocked_trans";
2834 default: return "unknown thread state";
2835 }
2836 }
2837
2838 #ifndef PRODUCT
2839 void JavaThread::print_thread_state_on(outputStream *st) const {
2840 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2841 };
2842 void JavaThread::print_thread_state() const {
2843 print_thread_state_on(tty);
2844 };
2845 #endif // PRODUCT
2846
2847 // Called by Threads::print() for VM_PrintThreads operation
2848 void JavaThread::print_on(outputStream *st) const {
2849 st->print("\"%s\" ", get_thread_name());
2850 oop thread_oop = threadObj();
2851 if (thread_oop != NULL) {
2852 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2853 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2854 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2855 }
2856 Thread::print_on(st);
2857 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2858 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2859 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2860 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2861 }
2862 #ifndef PRODUCT
2863 print_thread_state_on(st);
2864 _safepoint_state->print_on(st);
2865 #endif // PRODUCT
2866 }
2867
2868 // Called by fatal error handler. The difference between this and
2869 // JavaThread::print() is that we can't grab lock or allocate memory.
2870 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2871 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2872 oop thread_obj = threadObj();
2873 if (thread_obj != NULL) {
2874 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2875 }
2876 st->print(" [");
2877 st->print("%s", _get_thread_state_name(_thread_state));
2878 if (osthread()) {
2879 st->print(", id=%d", osthread()->thread_id());
2880 }
2881 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2882 _stack_base - _stack_size, _stack_base);
2883 st->print("]");
2884 return;
2885 }
2886
2887 // Verification
2888
2889 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2890
2891 void JavaThread::verify() {
2892 // Verify oops in the thread.
2893 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2894
2895 // Verify the stack frames.
2896 frames_do(frame_verify);
2897 }
2898
2899 // CR 6300358 (sub-CR 2137150)
2900 // Most callers of this method assume that it can't return NULL but a
2901 // thread may not have a name whilst it is in the process of attaching to
2902 // the VM - see CR 6412693, and there are places where a JavaThread can be
2903 // seen prior to having it's threadObj set (eg JNI attaching threads and
2904 // if vm exit occurs during initialization). These cases can all be accounted
2905 // for such that this method never returns NULL.
2906 const char* JavaThread::get_thread_name() const {
2907 #ifdef ASSERT
2908 // early safepoints can hit while current thread does not yet have TLS
2909 if (!SafepointSynchronize::is_at_safepoint()) {
2910 Thread *cur = Thread::current();
2911 if (!(cur->is_Java_thread() && cur == this)) {
2912 // Current JavaThreads are allowed to get their own name without
2913 // the Threads_lock.
2914 assert_locked_or_safepoint(Threads_lock);
2915 }
2916 }
2917 #endif // ASSERT
2918 return get_thread_name_string();
2919 }
2920
2921 // Returns a non-NULL representation of this thread's name, or a suitable
2922 // descriptive string if there is no set name
2923 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2924 const char* name_str;
2925 oop thread_obj = threadObj();
2926 if (thread_obj != NULL) {
2927 typeArrayOop name = java_lang_Thread::name(thread_obj);
2928 if (name != NULL) {
2929 if (buf == NULL) {
2930 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2931 }
2932 else {
2933 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2934 }
2935 }
2936 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2937 name_str = "<no-name - thread is attaching>";
2938 }
2939 else {
2940 name_str = Thread::name();
2941 }
2942 }
2943 else {
2944 name_str = Thread::name();
2945 }
2946 assert(name_str != NULL, "unexpected NULL thread name");
2947 return name_str;
2948 }
2949
2950
2951 const char* JavaThread::get_threadgroup_name() const {
2952 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2953 oop thread_obj = threadObj();
2954 if (thread_obj != NULL) {
2955 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2956 if (thread_group != NULL) {
2957 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2958 // ThreadGroup.name can be null
2959 if (name != NULL) {
2960 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2961 return str;
2962 }
2963 }
2964 }
2965 return NULL;
2966 }
2967
2968 const char* JavaThread::get_parent_name() const {
2969 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2970 oop thread_obj = threadObj();
2971 if (thread_obj != NULL) {
2972 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2973 if (thread_group != NULL) {
2974 oop parent = java_lang_ThreadGroup::parent(thread_group);
2975 if (parent != NULL) {
2976 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2977 // ThreadGroup.name can be null
2978 if (name != NULL) {
2979 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2980 return str;
2981 }
2982 }
2983 }
2984 }
2985 return NULL;
2986 }
2987
2988 ThreadPriority JavaThread::java_priority() const {
2989 oop thr_oop = threadObj();
2990 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2991 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2992 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2993 return priority;
2994 }
2995
2996 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2997
2998 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2999 // Link Java Thread object <-> C++ Thread
3000
3001 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3002 // and put it into a new Handle. The Handle "thread_oop" can then
3003 // be used to pass the C++ thread object to other methods.
3004
3005 // Set the Java level thread object (jthread) field of the
3006 // new thread (a JavaThread *) to C++ thread object using the
3007 // "thread_oop" handle.
3008
3009 // Set the thread field (a JavaThread *) of the
3010 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3011
3012 Handle thread_oop(Thread::current(),
3013 JNIHandles::resolve_non_null(jni_thread));
3014 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3015 "must be initialized");
3016 set_threadObj(thread_oop());
3017 java_lang_Thread::set_thread(thread_oop(), this);
3018
3019 if (prio == NoPriority) {
3020 prio = java_lang_Thread::priority(thread_oop());
3021 assert(prio != NoPriority, "A valid priority should be present");
3022 }
3023
3024 // Push the Java priority down to the native thread; needs Threads_lock
3025 Thread::set_priority(this, prio);
3026
3027 prepare_ext();
3028
3029 // Add the new thread to the Threads list and set it in motion.
3030 // We must have threads lock in order to call Threads::add.
3031 // It is crucial that we do not block before the thread is
3032 // added to the Threads list for if a GC happens, then the java_thread oop
3033 // will not be visited by GC.
3034 Threads::add(this);
3035 }
3036
3037 oop JavaThread::current_park_blocker() {
3038 // Support for JSR-166 locks
3039 oop thread_oop = threadObj();
3040 if (thread_oop != NULL &&
3041 JDK_Version::current().supports_thread_park_blocker()) {
3042 return java_lang_Thread::park_blocker(thread_oop);
3043 }
3044 return NULL;
3045 }
3046
3047
3048 void JavaThread::print_stack_on(outputStream* st) {
3049 if (!has_last_Java_frame()) return;
3050 ResourceMark rm;
3051 HandleMark hm;
3052
3053 RegisterMap reg_map(this);
3054 vframe* start_vf = last_java_vframe(®_map);
3055 int count = 0;
3056 for (vframe* f = start_vf; f; f = f->sender() ) {
3057 if (f->is_java_frame()) {
3058 javaVFrame* jvf = javaVFrame::cast(f);
3059 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3060
3061 // Print out lock information
3062 if (JavaMonitorsInStackTrace) {
3063 jvf->print_lock_info_on(st, count);
3064 }
3065 } else {
3066 // Ignore non-Java frames
3067 }
3068
3069 // Bail-out case for too deep stacks
3070 count++;
3071 if (MaxJavaStackTraceDepth == count) return;
3072 }
3073 }
3074
3075
3076 // JVMTI PopFrame support
3077 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3078 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3079 if (in_bytes(size_in_bytes) != 0) {
3080 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3081 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3082 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3083 }
3084 }
3085
3086 void* JavaThread::popframe_preserved_args() {
3087 return _popframe_preserved_args;
3088 }
3089
3090 ByteSize JavaThread::popframe_preserved_args_size() {
3091 return in_ByteSize(_popframe_preserved_args_size);
3092 }
3093
3094 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3095 int sz = in_bytes(popframe_preserved_args_size());
3096 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3097 return in_WordSize(sz / wordSize);
3098 }
3099
3100 void JavaThread::popframe_free_preserved_args() {
3101 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3102 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3103 _popframe_preserved_args = NULL;
3104 _popframe_preserved_args_size = 0;
3105 }
3106
3107 #ifndef PRODUCT
3108
3109 void JavaThread::trace_frames() {
3110 tty->print_cr("[Describe stack]");
3111 int frame_no = 1;
3112 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3113 tty->print(" %d. ", frame_no++);
3114 fst.current()->print_value_on(tty,this);
3115 tty->cr();
3116 }
3117 }
3118
3119 class PrintAndVerifyOopClosure: public OopClosure {
3120 protected:
3121 template <class T> inline void do_oop_work(T* p) {
3122 oop obj = oopDesc::load_decode_heap_oop(p);
3123 if (obj == NULL) return;
3124 tty->print(INTPTR_FORMAT ": ", p);
3125 if (obj->is_oop_or_null()) {
3126 if (obj->is_objArray()) {
3127 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3128 } else {
3129 obj->print();
3130 }
3131 } else {
3132 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3133 }
3134 tty->cr();
3135 }
3136 public:
3137 virtual void do_oop(oop* p) { do_oop_work(p); }
3138 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3139 };
3140
3141
3142 static void oops_print(frame* f, const RegisterMap *map) {
3143 PrintAndVerifyOopClosure print;
3144 f->print_value();
3145 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3146 }
3147
3148 // Print our all the locations that contain oops and whether they are
3149 // valid or not. This useful when trying to find the oldest frame
3150 // where an oop has gone bad since the frame walk is from youngest to
3151 // oldest.
3152 void JavaThread::trace_oops() {
3153 tty->print_cr("[Trace oops]");
3154 frames_do(oops_print);
3155 }
3156
3157
3158 #ifdef ASSERT
3159 // Print or validate the layout of stack frames
3160 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3161 ResourceMark rm;
3162 PRESERVE_EXCEPTION_MARK;
3163 FrameValues values;
3164 int frame_no = 0;
3165 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3166 fst.current()->describe(values, ++frame_no);
3167 if (depth == frame_no) break;
3168 }
3169 if (validate_only) {
3170 values.validate();
3171 } else {
3172 tty->print_cr("[Describe stack layout]");
3173 values.print(this);
3174 }
3175 }
3176 #endif
3177
3178 void JavaThread::trace_stack_from(vframe* start_vf) {
3179 ResourceMark rm;
3180 int vframe_no = 1;
3181 for (vframe* f = start_vf; f; f = f->sender() ) {
3182 if (f->is_java_frame()) {
3183 javaVFrame::cast(f)->print_activation(vframe_no++);
3184 } else {
3185 f->print();
3186 }
3187 if (vframe_no > StackPrintLimit) {
3188 tty->print_cr("...<more frames>...");
3189 return;
3190 }
3191 }
3192 }
3193
3194
3195 void JavaThread::trace_stack() {
3196 if (!has_last_Java_frame()) return;
3197 ResourceMark rm;
3198 HandleMark hm;
3199 RegisterMap reg_map(this);
3200 trace_stack_from(last_java_vframe(®_map));
3201 }
3202
3203
3204 #endif // PRODUCT
3205
3206
3207 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3208 assert(reg_map != NULL, "a map must be given");
3209 frame f = last_frame();
3210 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3211 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3212 }
3213 return NULL;
3214 }
3215
3216
3217 Klass* JavaThread::security_get_caller_class(int depth) {
3218 vframeStream vfst(this);
3219 vfst.security_get_caller_frame(depth);
3220 if (!vfst.at_end()) {
3221 return vfst.method()->method_holder();
3222 }
3223 return NULL;
3224 }
3225
3226 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3227 assert(thread->is_Compiler_thread(), "must be compiler thread");
3228 CompileBroker::compiler_thread_loop();
3229 }
3230
3231 // Create a CompilerThread
3232 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3233 : JavaThread(&compiler_thread_entry) {
3234 _env = NULL;
3235 _log = NULL;
3236 _task = NULL;
3237 _queue = queue;
3238 _counters = counters;
3239 _buffer_blob = NULL;
3240 _scanned_nmethod = NULL;
3241 _compiler = NULL;
3242
3243 #ifndef PRODUCT
3244 _ideal_graph_printer = NULL;
3245 #endif
3246 }
3247
3248 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3249 JavaThread::oops_do(f, cld_f, cf);
3250 if (_scanned_nmethod != NULL && cf != NULL) {
3251 // Safepoints can occur when the sweeper is scanning an nmethod so
3252 // process it here to make sure it isn't unloaded in the middle of
3253 // a scan.
3254 cf->do_code_blob(_scanned_nmethod);
3255 }
3256 }
3257
3258
3259 // ======= Threads ========
3260
3261 // The Threads class links together all active threads, and provides
3262 // operations over all threads. It is protected by its own Mutex
3263 // lock, which is also used in other contexts to protect thread
3264 // operations from having the thread being operated on from exiting
3265 // and going away unexpectedly (e.g., safepoint synchronization)
3266
3267 JavaThread* Threads::_thread_list = NULL;
3268 int Threads::_number_of_threads = 0;
3269 int Threads::_number_of_non_daemon_threads = 0;
3270 int Threads::_return_code = 0;
3271 size_t JavaThread::_stack_size_at_create = 0;
3272 #ifdef ASSERT
3273 bool Threads::_vm_complete = false;
3274 #endif
3275
3276 // All JavaThreads
3277 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3278
3279 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3280 void Threads::threads_do(ThreadClosure* tc) {
3281 assert_locked_or_safepoint(Threads_lock);
3282 // ALL_JAVA_THREADS iterates through all JavaThreads
3283 ALL_JAVA_THREADS(p) {
3284 tc->do_thread(p);
3285 }
3286 // Someday we could have a table or list of all non-JavaThreads.
3287 // For now, just manually iterate through them.
3288 tc->do_thread(VMThread::vm_thread());
3289 Universe::heap()->gc_threads_do(tc);
3290 WatcherThread *wt = WatcherThread::watcher_thread();
3291 // Strictly speaking, the following NULL check isn't sufficient to make sure
3292 // the data for WatcherThread is still valid upon being examined. However,
3293 // considering that WatchThread terminates when the VM is on the way to
3294 // exit at safepoint, the chance of the above is extremely small. The right
3295 // way to prevent termination of WatcherThread would be to acquire
3296 // Terminator_lock, but we can't do that without violating the lock rank
3297 // checking in some cases.
3298 if (wt != NULL)
3299 tc->do_thread(wt);
3300
3301 // If CompilerThreads ever become non-JavaThreads, add them here
3302 }
3303
3304 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3305
3306 extern void JDK_Version_init();
3307
3308 // Check version
3309 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3310
3311 // Initialize the output stream module
3312 ostream_init();
3313
3314 // Process java launcher properties.
3315 Arguments::process_sun_java_launcher_properties(args);
3316
3317 // Initialize the os module before using TLS
3318 os::init();
3319
3320 // Initialize system properties.
3321 Arguments::init_system_properties();
3322
3323 // So that JDK version can be used as a discrimintor when parsing arguments
3324 JDK_Version_init();
3325
3326 // Update/Initialize System properties after JDK version number is known
3327 Arguments::init_version_specific_system_properties();
3328
3329 // Parse arguments
3330 jint parse_result = Arguments::parse(args);
3331 if (parse_result != JNI_OK) return parse_result;
3332
3333 os::init_before_ergo();
3334
3335 jint ergo_result = Arguments::apply_ergo();
3336 if (ergo_result != JNI_OK) return ergo_result;
3337
3338 if (PauseAtStartup) {
3339 os::pause();
3340 }
3341
3342 #ifndef USDT2
3343 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3344 #else /* USDT2 */
3345 HOTSPOT_VM_INIT_BEGIN();
3346 #endif /* USDT2 */
3347
3348 // Record VM creation timing statistics
3349 TraceVmCreationTime create_vm_timer;
3350 create_vm_timer.start();
3351
3352 // Timing (must come after argument parsing)
3353 TraceTime timer("Create VM", TraceStartupTime);
3354
3355 // Initialize the os module after parsing the args
3356 jint os_init_2_result = os::init_2();
3357 if (os_init_2_result != JNI_OK) return os_init_2_result;
3358
3359 jint adjust_after_os_result = Arguments::adjust_after_os();
3360 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3361
3362 // intialize TLS
3363 ThreadLocalStorage::init();
3364
3365 // Initialize output stream logging
3366 ostream_init_log();
3367
3368 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3369 // Must be before create_vm_init_agents()
3370 if (Arguments::init_libraries_at_startup()) {
3371 convert_vm_init_libraries_to_agents();
3372 }
3373
3374 // Launch -agentlib/-agentpath and converted -Xrun agents
3375 if (Arguments::init_agents_at_startup()) {
3376 create_vm_init_agents();
3377 }
3378
3379 // Initialize Threads state
3380 _thread_list = NULL;
3381 _number_of_threads = 0;
3382 _number_of_non_daemon_threads = 0;
3383
3384 // Initialize global data structures and create system classes in heap
3385 vm_init_globals();
3386
3387 // Attach the main thread to this os thread
3388 JavaThread* main_thread = new JavaThread();
3389 main_thread->set_thread_state(_thread_in_vm);
3390 // must do this before set_active_handles and initialize_thread_local_storage
3391 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3392 // change the stack size recorded here to one based on the java thread
3393 // stacksize. This adjusted size is what is used to figure the placement
3394 // of the guard pages.
3395 main_thread->record_stack_base_and_size();
3396 main_thread->initialize_thread_local_storage();
3397
3398 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3399
3400 if (!main_thread->set_as_starting_thread()) {
3401 vm_shutdown_during_initialization(
3402 "Failed necessary internal allocation. Out of swap space");
3403 delete main_thread;
3404 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3405 return JNI_ENOMEM;
3406 }
3407
3408 // Enable guard page *after* os::create_main_thread(), otherwise it would
3409 // crash Linux VM, see notes in os_linux.cpp.
3410 main_thread->create_stack_guard_pages();
3411
3412 // Initialize Java-Level synchronization subsystem
3413 ObjectMonitor::Initialize() ;
3414
3415 // Initialize global modules
3416 jint status = init_globals();
3417 if (status != JNI_OK) {
3418 delete main_thread;
3419 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3420 return status;
3421 }
3422
3423 // Should be done after the heap is fully created
3424 main_thread->cache_global_variables();
3425
3426 HandleMark hm;
3427
3428 { MutexLocker mu(Threads_lock);
3429 Threads::add(main_thread);
3430 }
3431
3432 // Any JVMTI raw monitors entered in onload will transition into
3433 // real raw monitor. VM is setup enough here for raw monitor enter.
3434 JvmtiExport::transition_pending_onload_raw_monitors();
3435
3436 // Create the VMThread
3437 { TraceTime timer("Start VMThread", TraceStartupTime);
3438 VMThread::create();
3439 Thread* vmthread = VMThread::vm_thread();
3440
3441 if (!os::create_thread(vmthread, os::vm_thread))
3442 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3443
3444 // Wait for the VM thread to become ready, and VMThread::run to initialize
3445 // Monitors can have spurious returns, must always check another state flag
3446 {
3447 MutexLocker ml(Notify_lock);
3448 os::start_thread(vmthread);
3449 while (vmthread->active_handles() == NULL) {
3450 Notify_lock->wait();
3451 }
3452 }
3453 }
3454
3455 assert (Universe::is_fully_initialized(), "not initialized");
3456 if (VerifyDuringStartup) {
3457 // Make sure we're starting with a clean slate.
3458 VM_Verify verify_op;
3459 VMThread::execute(&verify_op);
3460 }
3461
3462 EXCEPTION_MARK;
3463
3464 // At this point, the Universe is initialized, but we have not executed
3465 // any byte code. Now is a good time (the only time) to dump out the
3466 // internal state of the JVM for sharing.
3467 if (DumpSharedSpaces) {
3468 MetaspaceShared::preload_and_dump(CHECK_0);
3469 ShouldNotReachHere();
3470 }
3471
3472 // Always call even when there are not JVMTI environments yet, since environments
3473 // may be attached late and JVMTI must track phases of VM execution
3474 JvmtiExport::enter_start_phase();
3475
3476 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3477 JvmtiExport::post_vm_start();
3478
3479 {
3480 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3481
3482 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3483 create_vm_init_libraries();
3484 }
3485
3486 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3487
3488 // Initialize java_lang.System (needed before creating the thread)
3489 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3490 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3491 Handle thread_group = create_initial_thread_group(CHECK_0);
3492 Universe::set_main_thread_group(thread_group());
3493 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3494 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3495 main_thread->set_threadObj(thread_object);
3496 // Set thread status to running since main thread has
3497 // been started and running.
3498 java_lang_Thread::set_thread_status(thread_object,
3499 java_lang_Thread::RUNNABLE);
3500
3501 // The VM creates & returns objects of this class. Make sure it's initialized.
3502 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3503
3504 // The VM preresolves methods to these classes. Make sure that they get initialized
3505 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3506 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3507 call_initializeSystemClass(CHECK_0);
3508
3509 // get the Java runtime name after java.lang.System is initialized
3510 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3511 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3512
3513 // an instance of OutOfMemory exception has been allocated earlier
3514 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3515 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3516 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3517 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3518 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3519 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3520 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3521 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3522 }
3523
3524 // See : bugid 4211085.
3525 // Background : the static initializer of java.lang.Compiler tries to read
3526 // property"java.compiler" and read & write property "java.vm.info".
3527 // When a security manager is installed through the command line
3528 // option "-Djava.security.manager", the above properties are not
3529 // readable and the static initializer for java.lang.Compiler fails
3530 // resulting in a NoClassDefFoundError. This can happen in any
3531 // user code which calls methods in java.lang.Compiler.
3532 // Hack : the hack is to pre-load and initialize this class, so that only
3533 // system domains are on the stack when the properties are read.
3534 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3535 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3536 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3537 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3538 // Once that is done, we should remove this hack.
3539 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3540
3541 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3542 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3543 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3544 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3545 // This should also be taken out as soon as 4211383 gets fixed.
3546 reset_vm_info_property(CHECK_0);
3547
3548 quicken_jni_functions();
3549
3550 // Must be run after init_ft which initializes ft_enabled
3551 if (TRACE_INITIALIZE() != JNI_OK) {
3552 vm_exit_during_initialization("Failed to initialize tracing backend");
3553 }
3554
3555 // Set flag that basic initialization has completed. Used by exceptions and various
3556 // debug stuff, that does not work until all basic classes have been initialized.
3557 set_init_completed();
3558
3559 Metaspace::post_initialize();
3560
3561 #ifndef USDT2
3562 HS_DTRACE_PROBE(hotspot, vm__init__end);
3563 #else /* USDT2 */
3564 HOTSPOT_VM_INIT_END();
3565 #endif /* USDT2 */
3566
3567 // record VM initialization completion time
3568 #if INCLUDE_MANAGEMENT
3569 Management::record_vm_init_completed();
3570 #endif // INCLUDE_MANAGEMENT
3571
3572 // Compute system loader. Note that this has to occur after set_init_completed, since
3573 // valid exceptions may be thrown in the process.
3574 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3575 // set_init_completed has just been called, causing exceptions not to be shortcut
3576 // anymore. We call vm_exit_during_initialization directly instead.
3577 SystemDictionary::compute_java_system_loader(THREAD);
3578 if (HAS_PENDING_EXCEPTION) {
3579 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3580 }
3581
3582 #if INCLUDE_ALL_GCS
3583 // Support for ConcurrentMarkSweep. This should be cleaned up
3584 // and better encapsulated. The ugly nested if test would go away
3585 // once things are properly refactored. XXX YSR
3586 if (UseConcMarkSweepGC || UseG1GC) {
3587 if (UseConcMarkSweepGC) {
3588 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3589 } else {
3590 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3591 }
3592 if (HAS_PENDING_EXCEPTION) {
3593 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3594 }
3595 }
3596 #endif // INCLUDE_ALL_GCS
3597
3598 // Always call even when there are not JVMTI environments yet, since environments
3599 // may be attached late and JVMTI must track phases of VM execution
3600 JvmtiExport::enter_live_phase();
3601
3602 // Signal Dispatcher needs to be started before VMInit event is posted
3603 os::signal_init();
3604
3605 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3606 if (!DisableAttachMechanism) {
3607 AttachListener::vm_start();
3608 if (StartAttachListener || AttachListener::init_at_startup()) {
3609 AttachListener::init();
3610 }
3611 }
3612
3613 // Launch -Xrun agents
3614 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3615 // back-end can launch with -Xdebug -Xrunjdwp.
3616 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3617 create_vm_init_libraries();
3618 }
3619
3620 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3621 JvmtiExport::post_vm_initialized();
3622
3623 if (TRACE_START() != JNI_OK) {
3624 vm_exit_during_initialization("Failed to start tracing backend.");
3625 }
3626
3627 if (CleanChunkPoolAsync) {
3628 Chunk::start_chunk_pool_cleaner_task();
3629 }
3630
3631 // initialize compiler(s)
3632 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3633 CompileBroker::compilation_init();
3634 #endif
3635
3636 if (EnableInvokeDynamic) {
3637 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3638 // It is done after compilers are initialized, because otherwise compilations of
3639 // signature polymorphic MH intrinsics can be missed
3640 // (see SystemDictionary::find_method_handle_intrinsic).
3641 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3642 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3643 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3644 }
3645
3646 #if INCLUDE_MANAGEMENT
3647 Management::initialize(THREAD);
3648 #endif // INCLUDE_MANAGEMENT
3649
3650 if (HAS_PENDING_EXCEPTION) {
3651 // management agent fails to start possibly due to
3652 // configuration problem and is responsible for printing
3653 // stack trace if appropriate. Simply exit VM.
3654 vm_exit(1);
3655 }
3656
3657 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3658 if (MemProfiling) MemProfiler::engage();
3659 StatSampler::engage();
3660 if (CheckJNICalls) JniPeriodicChecker::engage();
3661
3662 BiasedLocking::init();
3663
3664 #if INCLUDE_RTM_OPT
3665 RTMLockingCounters::init();
3666 #endif
3667
3668 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3669 call_postVMInitHook(THREAD);
3670 // The Java side of PostVMInitHook.run must deal with all
3671 // exceptions and provide means of diagnosis.
3672 if (HAS_PENDING_EXCEPTION) {
3673 CLEAR_PENDING_EXCEPTION;
3674 }
3675 }
3676
3677 {
3678 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3679 // Make sure the watcher thread can be started by WatcherThread::start()
3680 // or by dynamic enrollment.
3681 WatcherThread::make_startable();
3682 // Start up the WatcherThread if there are any periodic tasks
3683 // NOTE: All PeriodicTasks should be registered by now. If they
3684 // aren't, late joiners might appear to start slowly (we might
3685 // take a while to process their first tick).
3686 if (PeriodicTask::num_tasks() > 0) {
3687 WatcherThread::start();
3688 }
3689 }
3690
3691 // Give os specific code one last chance to start
3692 os::init_3();
3693
3694 create_vm_timer.end();
3695 #ifdef ASSERT
3696 _vm_complete = true;
3697 #endif
3698 return JNI_OK;
3699 }
3700
3701 // type for the Agent_OnLoad and JVM_OnLoad entry points
3702 extern "C" {
3703 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3704 }
3705 // Find a command line agent library and return its entry point for
3706 // -agentlib: -agentpath: -Xrun
3707 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3708 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3709 OnLoadEntry_t on_load_entry = NULL;
3710 void *library = NULL;
3711
3712 if (!agent->valid()) {
3713 char buffer[JVM_MAXPATHLEN];
3714 char ebuf[1024];
3715 const char *name = agent->name();
3716 const char *msg = "Could not find agent library ";
3717
3718 // First check to see if agent is statically linked into executable
3719 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3720 library = agent->os_lib();
3721 } else if (agent->is_absolute_path()) {
3722 library = os::dll_load(name, ebuf, sizeof ebuf);
3723 if (library == NULL) {
3724 const char *sub_msg = " in absolute path, with error: ";
3725 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3726 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3727 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3728 // If we can't find the agent, exit.
3729 vm_exit_during_initialization(buf, NULL);
3730 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3731 }
3732 } else {
3733 // Try to load the agent from the standard dll directory
3734 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3735 name)) {
3736 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3737 }
3738 if (library == NULL) { // Try the local directory
3739 char ns[1] = {0};
3740 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3741 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3742 }
3743 if (library == NULL) {
3744 const char *sub_msg = " on the library path, with error: ";
3745 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3746 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3747 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3748 // If we can't find the agent, exit.
3749 vm_exit_during_initialization(buf, NULL);
3750 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3751 }
3752 }
3753 }
3754 agent->set_os_lib(library);
3755 agent->set_valid();
3756 }
3757
3758 // Find the OnLoad function.
3759 on_load_entry =
3760 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3761 false,
3762 on_load_symbols,
3763 num_symbol_entries));
3764 return on_load_entry;
3765 }
3766
3767 // Find the JVM_OnLoad entry point
3768 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3769 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3770 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3771 }
3772
3773 // Find the Agent_OnLoad entry point
3774 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3775 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3776 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3777 }
3778
3779 // For backwards compatibility with -Xrun
3780 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3781 // treated like -agentpath:
3782 // Must be called before agent libraries are created
3783 void Threads::convert_vm_init_libraries_to_agents() {
3784 AgentLibrary* agent;
3785 AgentLibrary* next;
3786
3787 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3788 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3789 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3790
3791 // If there is an JVM_OnLoad function it will get called later,
3792 // otherwise see if there is an Agent_OnLoad
3793 if (on_load_entry == NULL) {
3794 on_load_entry = lookup_agent_on_load(agent);
3795 if (on_load_entry != NULL) {
3796 // switch it to the agent list -- so that Agent_OnLoad will be called,
3797 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3798 Arguments::convert_library_to_agent(agent);
3799 } else {
3800 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3801 }
3802 }
3803 }
3804 }
3805
3806 // Create agents for -agentlib: -agentpath: and converted -Xrun
3807 // Invokes Agent_OnLoad
3808 // Called very early -- before JavaThreads exist
3809 void Threads::create_vm_init_agents() {
3810 extern struct JavaVM_ main_vm;
3811 AgentLibrary* agent;
3812
3813 JvmtiExport::enter_onload_phase();
3814
3815 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3816 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3817
3818 if (on_load_entry != NULL) {
3819 // Invoke the Agent_OnLoad function
3820 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3821 if (err != JNI_OK) {
3822 vm_exit_during_initialization("agent library failed to init", agent->name());
3823 }
3824 } else {
3825 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3826 }
3827 }
3828 JvmtiExport::enter_primordial_phase();
3829 }
3830
3831 extern "C" {
3832 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3833 }
3834
3835 void Threads::shutdown_vm_agents() {
3836 // Send any Agent_OnUnload notifications
3837 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3838 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3839 extern struct JavaVM_ main_vm;
3840 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3841
3842 // Find the Agent_OnUnload function.
3843 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3844 os::find_agent_function(agent,
3845 false,
3846 on_unload_symbols,
3847 num_symbol_entries));
3848
3849 // Invoke the Agent_OnUnload function
3850 if (unload_entry != NULL) {
3851 JavaThread* thread = JavaThread::current();
3852 ThreadToNativeFromVM ttn(thread);
3853 HandleMark hm(thread);
3854 (*unload_entry)(&main_vm);
3855 }
3856 }
3857 }
3858
3859 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3860 // Invokes JVM_OnLoad
3861 void Threads::create_vm_init_libraries() {
3862 extern struct JavaVM_ main_vm;
3863 AgentLibrary* agent;
3864
3865 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3866 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3867
3868 if (on_load_entry != NULL) {
3869 // Invoke the JVM_OnLoad function
3870 JavaThread* thread = JavaThread::current();
3871 ThreadToNativeFromVM ttn(thread);
3872 HandleMark hm(thread);
3873 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3874 if (err != JNI_OK) {
3875 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3876 }
3877 } else {
3878 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3879 }
3880 }
3881 }
3882
3883 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3884 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3885
3886 JavaThread* java_thread = NULL;
3887 // Sequential search for now. Need to do better optimization later.
3888 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3889 oop tobj = thread->threadObj();
3890 if (!thread->is_exiting() &&
3891 tobj != NULL &&
3892 java_tid == java_lang_Thread::thread_id(tobj)) {
3893 java_thread = thread;
3894 break;
3895 }
3896 }
3897 return java_thread;
3898 }
3899
3900
3901 // Last thread running calls java.lang.Shutdown.shutdown()
3902 void JavaThread::invoke_shutdown_hooks() {
3903 HandleMark hm(this);
3904
3905 // We could get here with a pending exception, if so clear it now.
3906 if (this->has_pending_exception()) {
3907 this->clear_pending_exception();
3908 }
3909
3910 EXCEPTION_MARK;
3911 Klass* k =
3912 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3913 THREAD);
3914 if (k != NULL) {
3915 // SystemDictionary::resolve_or_null will return null if there was
3916 // an exception. If we cannot load the Shutdown class, just don't
3917 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3918 // and finalizers (if runFinalizersOnExit is set) won't be run.
3919 // Note that if a shutdown hook was registered or runFinalizersOnExit
3920 // was called, the Shutdown class would have already been loaded
3921 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3922 instanceKlassHandle shutdown_klass (THREAD, k);
3923 JavaValue result(T_VOID);
3924 JavaCalls::call_static(&result,
3925 shutdown_klass,
3926 vmSymbols::shutdown_method_name(),
3927 vmSymbols::void_method_signature(),
3928 THREAD);
3929 }
3930 CLEAR_PENDING_EXCEPTION;
3931 }
3932
3933 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3934 // the program falls off the end of main(). Another VM exit path is through
3935 // vm_exit() when the program calls System.exit() to return a value or when
3936 // there is a serious error in VM. The two shutdown paths are not exactly
3937 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3938 // and VM_Exit op at VM level.
3939 //
3940 // Shutdown sequence:
3941 // + Shutdown native memory tracking if it is on
3942 // + Wait until we are the last non-daemon thread to execute
3943 // <-- every thing is still working at this moment -->
3944 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3945 // shutdown hooks, run finalizers if finalization-on-exit
3946 // + Call before_exit(), prepare for VM exit
3947 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3948 // currently the only user of this mechanism is File.deleteOnExit())
3949 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3950 // post thread end and vm death events to JVMTI,
3951 // stop signal thread
3952 // + Call JavaThread::exit(), it will:
3953 // > release JNI handle blocks, remove stack guard pages
3954 // > remove this thread from Threads list
3955 // <-- no more Java code from this thread after this point -->
3956 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3957 // the compiler threads at safepoint
3958 // <-- do not use anything that could get blocked by Safepoint -->
3959 // + Disable tracing at JNI/JVM barriers
3960 // + Set _vm_exited flag for threads that are still running native code
3961 // + Delete this thread
3962 // + Call exit_globals()
3963 // > deletes tty
3964 // > deletes PerfMemory resources
3965 // + Return to caller
3966
3967 bool Threads::destroy_vm() {
3968 JavaThread* thread = JavaThread::current();
3969
3970 #ifdef ASSERT
3971 _vm_complete = false;
3972 #endif
3973 // Wait until we are the last non-daemon thread to execute
3974 { MutexLocker nu(Threads_lock);
3975 while (Threads::number_of_non_daemon_threads() > 1 )
3976 // This wait should make safepoint checks, wait without a timeout,
3977 // and wait as a suspend-equivalent condition.
3978 //
3979 // Note: If the FlatProfiler is running and this thread is waiting
3980 // for another non-daemon thread to finish, then the FlatProfiler
3981 // is waiting for the external suspend request on this thread to
3982 // complete. wait_for_ext_suspend_completion() will eventually
3983 // timeout, but that takes time. Making this wait a suspend-
3984 // equivalent condition solves that timeout problem.
3985 //
3986 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3987 Mutex::_as_suspend_equivalent_flag);
3988 }
3989
3990 // Hang forever on exit if we are reporting an error.
3991 if (ShowMessageBoxOnError && is_error_reported()) {
3992 os::infinite_sleep();
3993 }
3994 os::wait_for_keypress_at_exit();
3995
3996 if (JDK_Version::is_jdk12x_version()) {
3997 // We are the last thread running, so check if finalizers should be run.
3998 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3999 HandleMark rm(thread);
4000 Universe::run_finalizers_on_exit();
4001 } else {
4002 // run Java level shutdown hooks
4003 thread->invoke_shutdown_hooks();
4004 }
4005
4006 before_exit(thread);
4007
4008 thread->exit(true);
4009
4010 // Stop VM thread.
4011 {
4012 // 4945125 The vm thread comes to a safepoint during exit.
4013 // GC vm_operations can get caught at the safepoint, and the
4014 // heap is unparseable if they are caught. Grab the Heap_lock
4015 // to prevent this. The GC vm_operations will not be able to
4016 // queue until after the vm thread is dead. After this point,
4017 // we'll never emerge out of the safepoint before the VM exits.
4018
4019 MutexLocker ml(Heap_lock);
4020
4021 VMThread::wait_for_vm_thread_exit();
4022 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4023 VMThread::destroy();
4024 }
4025
4026 // clean up ideal graph printers
4027 #if defined(COMPILER2) && !defined(PRODUCT)
4028 IdealGraphPrinter::clean_up();
4029 #endif
4030
4031 // Now, all Java threads are gone except daemon threads. Daemon threads
4032 // running Java code or in VM are stopped by the Safepoint. However,
4033 // daemon threads executing native code are still running. But they
4034 // will be stopped at native=>Java/VM barriers. Note that we can't
4035 // simply kill or suspend them, as it is inherently deadlock-prone.
4036
4037 #ifndef PRODUCT
4038 // disable function tracing at JNI/JVM barriers
4039 TraceJNICalls = false;
4040 TraceJVMCalls = false;
4041 TraceRuntimeCalls = false;
4042 #endif
4043
4044 VM_Exit::set_vm_exited();
4045
4046 notify_vm_shutdown();
4047
4048 delete thread;
4049
4050 // exit_globals() will delete tty
4051 exit_globals();
4052
4053 return true;
4054 }
4055
4056
4057 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4058 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4059 return is_supported_jni_version(version);
4060 }
4061
4062
4063 jboolean Threads::is_supported_jni_version(jint version) {
4064 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4065 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4066 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4067 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4068 return JNI_FALSE;
4069 }
4070
4071
4072 void Threads::add(JavaThread* p, bool force_daemon) {
4073 // The threads lock must be owned at this point
4074 assert_locked_or_safepoint(Threads_lock);
4075
4076 // See the comment for this method in thread.hpp for its purpose and
4077 // why it is called here.
4078 p->initialize_queues();
4079 p->set_next(_thread_list);
4080 _thread_list = p;
4081 _number_of_threads++;
4082 oop threadObj = p->threadObj();
4083 bool daemon = true;
4084 // Bootstrapping problem: threadObj can be null for initial
4085 // JavaThread (or for threads attached via JNI)
4086 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4087 _number_of_non_daemon_threads++;
4088 daemon = false;
4089 }
4090
4091 ThreadService::add_thread(p, daemon);
4092
4093 // Possible GC point.
4094 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4095 }
4096
4097 void Threads::remove(JavaThread* p) {
4098 // Extra scope needed for Thread_lock, so we can check
4099 // that we do not remove thread without safepoint code notice
4100 { MutexLocker ml(Threads_lock);
4101
4102 assert(includes(p), "p must be present");
4103
4104 JavaThread* current = _thread_list;
4105 JavaThread* prev = NULL;
4106
4107 while (current != p) {
4108 prev = current;
4109 current = current->next();
4110 }
4111
4112 if (prev) {
4113 prev->set_next(current->next());
4114 } else {
4115 _thread_list = p->next();
4116 }
4117 _number_of_threads--;
4118 oop threadObj = p->threadObj();
4119 bool daemon = true;
4120 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4121 _number_of_non_daemon_threads--;
4122 daemon = false;
4123
4124 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4125 // on destroy_vm will wake up.
4126 if (number_of_non_daemon_threads() == 1)
4127 Threads_lock->notify_all();
4128 }
4129 ThreadService::remove_thread(p, daemon);
4130
4131 // Make sure that safepoint code disregard this thread. This is needed since
4132 // the thread might mess around with locks after this point. This can cause it
4133 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4134 // of this thread since it is removed from the queue.
4135 p->set_terminated_value();
4136 } // unlock Threads_lock
4137
4138 // Since Events::log uses a lock, we grab it outside the Threads_lock
4139 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4140 }
4141
4142 // Threads_lock must be held when this is called (or must be called during a safepoint)
4143 bool Threads::includes(JavaThread* p) {
4144 assert(Threads_lock->is_locked(), "sanity check");
4145 ALL_JAVA_THREADS(q) {
4146 if (q == p ) {
4147 return true;
4148 }
4149 }
4150 return false;
4151 }
4152
4153 // Operations on the Threads list for GC. These are not explicitly locked,
4154 // but the garbage collector must provide a safe context for them to run.
4155 // In particular, these things should never be called when the Threads_lock
4156 // is held by some other thread. (Note: the Safepoint abstraction also
4157 // uses the Threads_lock to gurantee this property. It also makes sure that
4158 // all threads gets blocked when exiting or starting).
4159
4160 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4161 ALL_JAVA_THREADS(p) {
4162 p->oops_do(f, cld_f, cf);
4163 }
4164 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4165 }
4166
4167 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4168 // Introduce a mechanism allowing parallel threads to claim threads as
4169 // root groups. Overhead should be small enough to use all the time,
4170 // even in sequential code.
4171 SharedHeap* sh = SharedHeap::heap();
4172 // Cannot yet substitute active_workers for n_par_threads
4173 // because of G1CollectedHeap::verify() use of
4174 // SharedHeap::process_roots(). n_par_threads == 0 will
4175 // turn off parallelism in process_roots while active_workers
4176 // is being used for parallelism elsewhere.
4177 bool is_par = sh->n_par_threads() > 0;
4178 assert(!is_par ||
4179 (SharedHeap::heap()->n_par_threads() ==
4180 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4181 int cp = SharedHeap::heap()->strong_roots_parity();
4182 ALL_JAVA_THREADS(p) {
4183 if (p->claim_oops_do(is_par, cp)) {
4184 p->oops_do(f, cld_f, cf);
4185 }
4186 }
4187 VMThread* vmt = VMThread::vm_thread();
4188 if (vmt->claim_oops_do(is_par, cp)) {
4189 vmt->oops_do(f, cld_f, cf);
4190 }
4191 }
4192
4193 #if INCLUDE_ALL_GCS
4194 // Used by ParallelScavenge
4195 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4196 ALL_JAVA_THREADS(p) {
4197 q->enqueue(new ThreadRootsTask(p));
4198 }
4199 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4200 }
4201
4202 // Used by Parallel Old
4203 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4204 ALL_JAVA_THREADS(p) {
4205 q->enqueue(new ThreadRootsMarkingTask(p));
4206 }
4207 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4208 }
4209 #endif // INCLUDE_ALL_GCS
4210
4211 void Threads::nmethods_do(CodeBlobClosure* cf) {
4212 ALL_JAVA_THREADS(p) {
4213 p->nmethods_do(cf);
4214 }
4215 VMThread::vm_thread()->nmethods_do(cf);
4216 }
4217
4218 void Threads::metadata_do(void f(Metadata*)) {
4219 ALL_JAVA_THREADS(p) {
4220 p->metadata_do(f);
4221 }
4222 }
4223
4224 void Threads::gc_epilogue() {
4225 ALL_JAVA_THREADS(p) {
4226 p->gc_epilogue();
4227 }
4228 }
4229
4230 void Threads::gc_prologue() {
4231 ALL_JAVA_THREADS(p) {
4232 p->gc_prologue();
4233 }
4234 }
4235
4236 void Threads::deoptimized_wrt_marked_nmethods() {
4237 ALL_JAVA_THREADS(p) {
4238 p->deoptimized_wrt_marked_nmethods();
4239 }
4240 }
4241
4242
4243 // Get count Java threads that are waiting to enter the specified monitor.
4244 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4245 address monitor, bool doLock) {
4246 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4247 "must grab Threads_lock or be at safepoint");
4248 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4249
4250 int i = 0;
4251 {
4252 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4253 ALL_JAVA_THREADS(p) {
4254 if (p->is_Compiler_thread()) continue;
4255
4256 address pending = (address)p->current_pending_monitor();
4257 if (pending == monitor) { // found a match
4258 if (i < count) result->append(p); // save the first count matches
4259 i++;
4260 }
4261 }
4262 }
4263 return result;
4264 }
4265
4266
4267 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4268 assert(doLock ||
4269 Threads_lock->owned_by_self() ||
4270 SafepointSynchronize::is_at_safepoint(),
4271 "must grab Threads_lock or be at safepoint");
4272
4273 // NULL owner means not locked so we can skip the search
4274 if (owner == NULL) return NULL;
4275
4276 {
4277 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4278 ALL_JAVA_THREADS(p) {
4279 // first, see if owner is the address of a Java thread
4280 if (owner == (address)p) return p;
4281 }
4282 }
4283 // Cannot assert on lack of success here since this function may be
4284 // used by code that is trying to report useful problem information
4285 // like deadlock detection.
4286 if (UseHeavyMonitors) return NULL;
4287
4288 //
4289 // If we didn't find a matching Java thread and we didn't force use of
4290 // heavyweight monitors, then the owner is the stack address of the
4291 // Lock Word in the owning Java thread's stack.
4292 //
4293 JavaThread* the_owner = NULL;
4294 {
4295 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4296 ALL_JAVA_THREADS(q) {
4297 if (q->is_lock_owned(owner)) {
4298 the_owner = q;
4299 break;
4300 }
4301 }
4302 }
4303 // cannot assert on lack of success here; see above comment
4304 return the_owner;
4305 }
4306
4307 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4308 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4309 char buf[32];
4310 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4311
4312 st->print_cr("Full thread dump %s (%s %s):",
4313 Abstract_VM_Version::vm_name(),
4314 Abstract_VM_Version::vm_release(),
4315 Abstract_VM_Version::vm_info_string()
4316 );
4317 st->cr();
4318
4319 #if INCLUDE_ALL_GCS
4320 // Dump concurrent locks
4321 ConcurrentLocksDump concurrent_locks;
4322 if (print_concurrent_locks) {
4323 concurrent_locks.dump_at_safepoint();
4324 }
4325 #endif // INCLUDE_ALL_GCS
4326
4327 ALL_JAVA_THREADS(p) {
4328 ResourceMark rm;
4329 p->print_on(st);
4330 if (print_stacks) {
4331 if (internal_format) {
4332 p->trace_stack();
4333 } else {
4334 p->print_stack_on(st);
4335 }
4336 }
4337 st->cr();
4338 #if INCLUDE_ALL_GCS
4339 if (print_concurrent_locks) {
4340 concurrent_locks.print_locks_on(p, st);
4341 }
4342 #endif // INCLUDE_ALL_GCS
4343 }
4344
4345 VMThread::vm_thread()->print_on(st);
4346 st->cr();
4347 Universe::heap()->print_gc_threads_on(st);
4348 WatcherThread* wt = WatcherThread::watcher_thread();
4349 if (wt != NULL) {
4350 wt->print_on(st);
4351 st->cr();
4352 }
4353 CompileBroker::print_compiler_threads_on(st);
4354 st->flush();
4355 }
4356
4357 // Threads::print_on_error() is called by fatal error handler. It's possible
4358 // that VM is not at safepoint and/or current thread is inside signal handler.
4359 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4360 // memory (even in resource area), it might deadlock the error handler.
4361 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4362 bool found_current = false;
4363 st->print_cr("Java Threads: ( => current thread )");
4364 ALL_JAVA_THREADS(thread) {
4365 bool is_current = (current == thread);
4366 found_current = found_current || is_current;
4367
4368 st->print("%s", is_current ? "=>" : " ");
4369
4370 st->print(PTR_FORMAT, thread);
4371 st->print(" ");
4372 thread->print_on_error(st, buf, buflen);
4373 st->cr();
4374 }
4375 st->cr();
4376
4377 st->print_cr("Other Threads:");
4378 if (VMThread::vm_thread()) {
4379 bool is_current = (current == VMThread::vm_thread());
4380 found_current = found_current || is_current;
4381 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4382
4383 st->print(PTR_FORMAT, VMThread::vm_thread());
4384 st->print(" ");
4385 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4386 st->cr();
4387 }
4388 WatcherThread* wt = WatcherThread::watcher_thread();
4389 if (wt != NULL) {
4390 bool is_current = (current == wt);
4391 found_current = found_current || is_current;
4392 st->print("%s", is_current ? "=>" : " ");
4393
4394 st->print(PTR_FORMAT, wt);
4395 st->print(" ");
4396 wt->print_on_error(st, buf, buflen);
4397 st->cr();
4398 }
4399 if (!found_current) {
4400 st->cr();
4401 st->print("=>" PTR_FORMAT " (exited) ", current);
4402 current->print_on_error(st, buf, buflen);
4403 st->cr();
4404 }
4405 }
4406
4407 // Internal SpinLock and Mutex
4408 // Based on ParkEvent
4409
4410 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4411 //
4412 // We employ SpinLocks _only for low-contention, fixed-length
4413 // short-duration critical sections where we're concerned
4414 // about native mutex_t or HotSpot Mutex:: latency.
4415 // The mux construct provides a spin-then-block mutual exclusion
4416 // mechanism.
4417 //
4418 // Testing has shown that contention on the ListLock guarding gFreeList
4419 // is common. If we implement ListLock as a simple SpinLock it's common
4420 // for the JVM to devolve to yielding with little progress. This is true
4421 // despite the fact that the critical sections protected by ListLock are
4422 // extremely short.
4423 //
4424 // TODO-FIXME: ListLock should be of type SpinLock.
4425 // We should make this a 1st-class type, integrated into the lock
4426 // hierarchy as leaf-locks. Critically, the SpinLock structure
4427 // should have sufficient padding to avoid false-sharing and excessive
4428 // cache-coherency traffic.
4429
4430
4431 typedef volatile int SpinLockT ;
4432
4433 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4434 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4435 return ; // normal fast-path return
4436 }
4437
4438 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4439 TEVENT (SpinAcquire - ctx) ;
4440 int ctr = 0 ;
4441 int Yields = 0 ;
4442 for (;;) {
4443 while (*adr != 0) {
4444 ++ctr ;
4445 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4446 if (Yields > 5) {
4447 os::naked_short_sleep(1);
4448 } else {
4449 os::NakedYield() ;
4450 ++Yields ;
4451 }
4452 } else {
4453 SpinPause() ;
4454 }
4455 }
4456 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4457 }
4458 }
4459
4460 void Thread::SpinRelease (volatile int * adr) {
4461 assert (*adr != 0, "invariant") ;
4462 OrderAccess::fence() ; // guarantee at least release consistency.
4463 // Roach-motel semantics.
4464 // It's safe if subsequent LDs and STs float "up" into the critical section,
4465 // but prior LDs and STs within the critical section can't be allowed
4466 // to reorder or float past the ST that releases the lock.
4467 *adr = 0 ;
4468 }
4469
4470 // muxAcquire and muxRelease:
4471 //
4472 // * muxAcquire and muxRelease support a single-word lock-word construct.
4473 // The LSB of the word is set IFF the lock is held.
4474 // The remainder of the word points to the head of a singly-linked list
4475 // of threads blocked on the lock.
4476 //
4477 // * The current implementation of muxAcquire-muxRelease uses its own
4478 // dedicated Thread._MuxEvent instance. If we're interested in
4479 // minimizing the peak number of extant ParkEvent instances then
4480 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4481 // as certain invariants were satisfied. Specifically, care would need
4482 // to be taken with regards to consuming unpark() "permits".
4483 // A safe rule of thumb is that a thread would never call muxAcquire()
4484 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4485 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4486 // consume an unpark() permit intended for monitorenter, for instance.
4487 // One way around this would be to widen the restricted-range semaphore
4488 // implemented in park(). Another alternative would be to provide
4489 // multiple instances of the PlatformEvent() for each thread. One
4490 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4491 //
4492 // * Usage:
4493 // -- Only as leaf locks
4494 // -- for short-term locking only as muxAcquire does not perform
4495 // thread state transitions.
4496 //
4497 // Alternatives:
4498 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4499 // but with parking or spin-then-park instead of pure spinning.
4500 // * Use Taura-Oyama-Yonenzawa locks.
4501 // * It's possible to construct a 1-0 lock if we encode the lockword as
4502 // (List,LockByte). Acquire will CAS the full lockword while Release
4503 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4504 // acquiring threads use timers (ParkTimed) to detect and recover from
4505 // the stranding window. Thread/Node structures must be aligned on 256-byte
4506 // boundaries by using placement-new.
4507 // * Augment MCS with advisory back-link fields maintained with CAS().
4508 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4509 // The validity of the backlinks must be ratified before we trust the value.
4510 // If the backlinks are invalid the exiting thread must back-track through the
4511 // the forward links, which are always trustworthy.
4512 // * Add a successor indication. The LockWord is currently encoded as
4513 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4514 // to provide the usual futile-wakeup optimization.
4515 // See RTStt for details.
4516 // * Consider schedctl.sc_nopreempt to cover the critical section.
4517 //
4518
4519
4520 typedef volatile intptr_t MutexT ; // Mux Lock-word
4521 enum MuxBits { LOCKBIT = 1 } ;
4522
4523 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4524 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4525 if (w == 0) return ;
4526 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4527 return ;
4528 }
4529
4530 TEVENT (muxAcquire - Contention) ;
4531 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4532 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4533 for (;;) {
4534 int its = (os::is_MP() ? 100 : 0) + 1 ;
4535
4536 // Optional spin phase: spin-then-park strategy
4537 while (--its >= 0) {
4538 w = *Lock ;
4539 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4540 return ;
4541 }
4542 }
4543
4544 Self->reset() ;
4545 Self->OnList = intptr_t(Lock) ;
4546 // The following fence() isn't _strictly necessary as the subsequent
4547 // CAS() both serializes execution and ratifies the fetched *Lock value.
4548 OrderAccess::fence();
4549 for (;;) {
4550 w = *Lock ;
4551 if ((w & LOCKBIT) == 0) {
4552 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4553 Self->OnList = 0 ; // hygiene - allows stronger asserts
4554 return ;
4555 }
4556 continue ; // Interference -- *Lock changed -- Just retry
4557 }
4558 assert (w & LOCKBIT, "invariant") ;
4559 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4560 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4561 }
4562
4563 while (Self->OnList != 0) {
4564 Self->park() ;
4565 }
4566 }
4567 }
4568
4569 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4570 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4571 if (w == 0) return ;
4572 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4573 return ;
4574 }
4575
4576 TEVENT (muxAcquire - Contention) ;
4577 ParkEvent * ReleaseAfter = NULL ;
4578 if (ev == NULL) {
4579 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4580 }
4581 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4582 for (;;) {
4583 guarantee (ev->OnList == 0, "invariant") ;
4584 int its = (os::is_MP() ? 100 : 0) + 1 ;
4585
4586 // Optional spin phase: spin-then-park strategy
4587 while (--its >= 0) {
4588 w = *Lock ;
4589 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4590 if (ReleaseAfter != NULL) {
4591 ParkEvent::Release (ReleaseAfter) ;
4592 }
4593 return ;
4594 }
4595 }
4596
4597 ev->reset() ;
4598 ev->OnList = intptr_t(Lock) ;
4599 // The following fence() isn't _strictly necessary as the subsequent
4600 // CAS() both serializes execution and ratifies the fetched *Lock value.
4601 OrderAccess::fence();
4602 for (;;) {
4603 w = *Lock ;
4604 if ((w & LOCKBIT) == 0) {
4605 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4606 ev->OnList = 0 ;
4607 // We call ::Release while holding the outer lock, thus
4608 // artificially lengthening the critical section.
4609 // Consider deferring the ::Release() until the subsequent unlock(),
4610 // after we've dropped the outer lock.
4611 if (ReleaseAfter != NULL) {
4612 ParkEvent::Release (ReleaseAfter) ;
4613 }
4614 return ;
4615 }
4616 continue ; // Interference -- *Lock changed -- Just retry
4617 }
4618 assert (w & LOCKBIT, "invariant") ;
4619 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4620 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4621 }
4622
4623 while (ev->OnList != 0) {
4624 ev->park() ;
4625 }
4626 }
4627 }
4628
4629 // Release() must extract a successor from the list and then wake that thread.
4630 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4631 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4632 // Release() would :
4633 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4634 // (B) Extract a successor from the private list "in-hand"
4635 // (C) attempt to CAS() the residual back into *Lock over null.
4636 // If there were any newly arrived threads and the CAS() would fail.
4637 // In that case Release() would detach the RATs, re-merge the list in-hand
4638 // with the RATs and repeat as needed. Alternately, Release() might
4639 // detach and extract a successor, but then pass the residual list to the wakee.
4640 // The wakee would be responsible for reattaching and remerging before it
4641 // competed for the lock.
4642 //
4643 // Both "pop" and DMR are immune from ABA corruption -- there can be
4644 // multiple concurrent pushers, but only one popper or detacher.
4645 // This implementation pops from the head of the list. This is unfair,
4646 // but tends to provide excellent throughput as hot threads remain hot.
4647 // (We wake recently run threads first).
4648
4649 void Thread::muxRelease (volatile intptr_t * Lock) {
4650 for (;;) {
4651 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4652 assert (w & LOCKBIT, "invariant") ;
4653 if (w == LOCKBIT) return ;
4654 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4655 assert (List != NULL, "invariant") ;
4656 assert (List->OnList == intptr_t(Lock), "invariant") ;
4657 ParkEvent * nxt = List->ListNext ;
4658
4659 // The following CAS() releases the lock and pops the head element.
4660 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4661 continue ;
4662 }
4663 List->OnList = 0 ;
4664 OrderAccess::fence() ;
4665 List->unpark () ;
4666 return ;
4667 }
4668 }
4669
4670
4671 void Threads::verify() {
4672 ALL_JAVA_THREADS(p) {
4673 p->verify();
4674 }
4675 VMThread* thread = VMThread::vm_thread();
4676 if (thread != NULL) thread->verify();
4677 }