1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jvmtifiles/jvmtiEnv.hpp"
36 #include "memory/gcLocker.inline.hpp"
37 #include "memory/metaspaceShared.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "memory/universe.inline.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/objArrayOop.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/symbol.hpp"
44 #include "prims/jvm_misc.hpp"
45 #include "prims/jvmtiExport.hpp"
46 #include "prims/jvmtiThreadState.hpp"
47 #include "prims/privilegedStack.hpp"
48 #include "runtime/arguments.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/deoptimization.hpp"
51 #include "runtime/fprofiler.hpp"
52 #include "runtime/frame.inline.hpp"
53 #include "runtime/init.hpp"
54 #include "runtime/interfaceSupport.hpp"
55 #include "runtime/java.hpp"
56 #include "runtime/javaCalls.hpp"
57 #include "runtime/jniPeriodicChecker.hpp"
58 #include "runtime/memprofiler.hpp"
59 #include "runtime/mutexLocker.hpp"
60 #include "runtime/objectMonitor.hpp"
61 #include "runtime/osThread.hpp"
62 #include "runtime/safepoint.hpp"
63 #include "runtime/sharedRuntime.hpp"
64 #include "runtime/statSampler.hpp"
65 #include "runtime/stubRoutines.hpp"
66 #include "runtime/task.hpp"
67 #include "runtime/thread.inline.hpp"
68 #include "runtime/threadCritical.hpp"
69 #include "runtime/threadLocalStorage.hpp"
70 #include "runtime/vframe.hpp"
71 #include "runtime/vframeArray.hpp"
72 #include "runtime/vframe_hp.hpp"
73 #include "runtime/vmThread.hpp"
74 #include "runtime/vm_operations.hpp"
75 #include "services/attachListener.hpp"
76 #include "services/management.hpp"
77 #include "services/memTracker.hpp"
78 #include "services/threadService.hpp"
79 #include "trace/tracing.hpp"
80 #include "trace/traceMacros.hpp"
81 #include "utilities/defaultStream.hpp"
82 #include "utilities/dtrace.hpp"
83 #include "utilities/events.hpp"
84 #include "utilities/preserveException.hpp"
85 #include "utilities/macros.hpp"
86 #ifdef TARGET_OS_FAMILY_linux
87 # include "os_linux.inline.hpp"
88 #endif
89 #ifdef TARGET_OS_FAMILY_solaris
90 # include "os_solaris.inline.hpp"
91 #endif
92 #ifdef TARGET_OS_FAMILY_windows
93 # include "os_windows.inline.hpp"
94 #endif
95 #ifdef TARGET_OS_FAMILY_bsd
96 # include "os_bsd.inline.hpp"
97 #endif
98 #if INCLUDE_ALL_GCS
99 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
100 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
101 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
102 #endif // INCLUDE_ALL_GCS
103 #ifdef COMPILER1
104 #include "c1/c1_Compiler.hpp"
105 #endif
106 #ifdef COMPILER2
107 #include "opto/c2compiler.hpp"
108 #include "opto/idealGraphPrinter.hpp"
109 #endif
110 #if INCLUDE_RTM_OPT
111 #include "runtime/rtmLocking.hpp"
112 #endif
113
114 #ifdef DTRACE_ENABLED
115
116 // Only bother with this argument setup if dtrace is available
117
118 #ifndef USDT2
119 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
120 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
121 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
122 intptr_t, intptr_t, bool);
123 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
124 intptr_t, intptr_t, bool);
125
126 #define DTRACE_THREAD_PROBE(probe, javathread) \
127 { \
128 ResourceMark rm(this); \
129 int len = 0; \
130 const char* name = (javathread)->get_thread_name(); \
131 len = strlen(name); \
132 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
133 name, len, \
134 java_lang_Thread::thread_id((javathread)->threadObj()), \
135 (javathread)->osthread()->thread_id(), \
136 java_lang_Thread::is_daemon((javathread)->threadObj())); \
137 }
138
139 #else /* USDT2 */
140
141 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
142 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
143
144 #define DTRACE_THREAD_PROBE(probe, javathread) \
145 { \
146 ResourceMark rm(this); \
147 int len = 0; \
148 const char* name = (javathread)->get_thread_name(); \
149 len = strlen(name); \
150 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
151 (char *) name, len, \
152 java_lang_Thread::thread_id((javathread)->threadObj()), \
153 (uintptr_t) (javathread)->osthread()->thread_id(), \
154 java_lang_Thread::is_daemon((javathread)->threadObj())); \
155 }
156
157 #endif /* USDT2 */
158
159 #else // ndef DTRACE_ENABLED
160
161 #define DTRACE_THREAD_PROBE(probe, javathread)
162
163 #endif // ndef DTRACE_ENABLED
164
165
166 // Class hierarchy
167 // - Thread
168 // - VMThread
169 // - WatcherThread
170 // - ConcurrentMarkSweepThread
171 // - JavaThread
172 // - CompilerThread
173
174 // ======= Thread ========
175 // Support for forcing alignment of thread objects for biased locking
176 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
177 if (UseBiasedLocking) {
178 const int alignment = markOopDesc::biased_lock_alignment;
179 size_t aligned_size = size + (alignment - sizeof(intptr_t));
180 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
181 : AllocateHeap(aligned_size, flags, CURRENT_PC,
182 AllocFailStrategy::RETURN_NULL);
183 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
184 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
185 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
186 "JavaThread alignment code overflowed allocated storage");
187 if (TraceBiasedLocking) {
188 if (aligned_addr != real_malloc_addr)
189 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
190 real_malloc_addr, aligned_addr);
191 }
192 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
193 return aligned_addr;
194 } else {
195 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
196 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
197 }
198 }
199
200 void Thread::operator delete(void* p) {
201 if (UseBiasedLocking) {
202 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
203 FreeHeap(real_malloc_addr, mtThread);
204 } else {
205 FreeHeap(p, mtThread);
206 }
207 }
208
209
210 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
211 // JavaThread
212
213
214 Thread::Thread() {
215 // stack and get_thread
216 set_stack_base(NULL);
217 set_stack_size(0);
218 set_self_raw_id(0);
219 set_lgrp_id(-1);
220
221 // allocated data structures
222 set_osthread(NULL);
223 set_resource_area(new (mtThread)ResourceArea());
224 DEBUG_ONLY(_current_resource_mark = NULL;)
225 set_handle_area(new (mtThread) HandleArea(NULL));
226 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
227 set_active_handles(NULL);
228 set_free_handle_block(NULL);
229 set_last_handle_mark(NULL);
230
231 // This initial value ==> never claimed.
232 _oops_do_parity = 0;
233
234 // the handle mark links itself to last_handle_mark
235 new HandleMark(this);
236
237 // plain initialization
238 debug_only(_owned_locks = NULL;)
239 debug_only(_allow_allocation_count = 0;)
240 NOT_PRODUCT(_allow_safepoint_count = 0;)
241 NOT_PRODUCT(_skip_gcalot = false;)
242 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
243 _jvmti_env_iteration_count = 0;
244 set_allocated_bytes(0);
245 _vm_operation_started_count = 0;
246 _vm_operation_completed_count = 0;
247 _current_pending_monitor = NULL;
248 _current_pending_monitor_is_from_java = true;
249 _current_waiting_monitor = NULL;
250 _num_nested_signal = 0;
251 omFreeList = NULL ;
252 omFreeCount = 0 ;
253 omFreeProvision = 32 ;
254 omInUseList = NULL ;
255 omInUseCount = 0 ;
256
257 #ifdef ASSERT
258 _visited_for_critical_count = false;
259 #endif
260
261 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
262 _suspend_flags = 0;
263
264 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
265 _hashStateX = os::random() ;
266 _hashStateY = 842502087 ;
267 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
268 _hashStateW = 273326509 ;
269
270 _OnTrap = 0 ;
271 _schedctl = NULL ;
272 _Stalled = 0 ;
273 _TypeTag = 0x2BAD ;
274
275 // Many of the following fields are effectively final - immutable
276 // Note that nascent threads can't use the Native Monitor-Mutex
277 // construct until the _MutexEvent is initialized ...
278 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
279 // we might instead use a stack of ParkEvents that we could provision on-demand.
280 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
281 // and ::Release()
282 _ParkEvent = ParkEvent::Allocate (this) ;
283 _SleepEvent = ParkEvent::Allocate (this) ;
284 _MutexEvent = ParkEvent::Allocate (this) ;
285 _MuxEvent = ParkEvent::Allocate (this) ;
286
287 #ifdef CHECK_UNHANDLED_OOPS
288 if (CheckUnhandledOops) {
289 _unhandled_oops = new UnhandledOops(this);
290 }
291 #endif // CHECK_UNHANDLED_OOPS
292 #ifdef ASSERT
293 if (UseBiasedLocking) {
294 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
295 assert(this == _real_malloc_address ||
296 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
297 "bug in forced alignment of thread objects");
298 }
299 #endif /* ASSERT */
300 }
301
302 void Thread::initialize_thread_local_storage() {
303 // Note: Make sure this method only calls
304 // non-blocking operations. Otherwise, it might not work
305 // with the thread-startup/safepoint interaction.
306
307 // During Java thread startup, safepoint code should allow this
308 // method to complete because it may need to allocate memory to
309 // store information for the new thread.
310
311 // initialize structure dependent on thread local storage
312 ThreadLocalStorage::set_thread(this);
313 }
314
315 void Thread::record_stack_base_and_size() {
316 set_stack_base(os::current_stack_base());
317 set_stack_size(os::current_stack_size());
318 // CR 7190089: on Solaris, primordial thread's stack is adjusted
319 // in initialize_thread(). Without the adjustment, stack size is
320 // incorrect if stack is set to unlimited (ulimit -s unlimited).
321 // So far, only Solaris has real implementation of initialize_thread().
322 //
323 // set up any platform-specific state.
324 os::initialize_thread(this);
325
326 #if INCLUDE_NMT
327 // record thread's native stack, stack grows downward
328 address stack_low_addr = stack_base() - stack_size();
329 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this,
330 CURRENT_PC);
331 #endif // INCLUDE_NMT
332 }
333
334
335 Thread::~Thread() {
336 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
337 ObjectSynchronizer::omFlush (this) ;
338
339 EVENT_THREAD_DESTRUCT(this);
340
341 // stack_base can be NULL if the thread is never started or exited before
342 // record_stack_base_and_size called. Although, we would like to ensure
343 // that all started threads do call record_stack_base_and_size(), there is
344 // not proper way to enforce that.
345 #if INCLUDE_NMT
346 if (_stack_base != NULL) {
347 address low_stack_addr = stack_base() - stack_size();
348 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this);
349 #ifdef ASSERT
350 set_stack_base(NULL);
351 #endif
352 }
353 #endif // INCLUDE_NMT
354
355 // deallocate data structures
356 delete resource_area();
357 // since the handle marks are using the handle area, we have to deallocated the root
358 // handle mark before deallocating the thread's handle area,
359 assert(last_handle_mark() != NULL, "check we have an element");
360 delete last_handle_mark();
361 assert(last_handle_mark() == NULL, "check we have reached the end");
362
363 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
364 // We NULL out the fields for good hygiene.
365 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
366 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
367 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
368 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
369
370 delete handle_area();
371 delete metadata_handles();
372
373 // osthread() can be NULL, if creation of thread failed.
374 if (osthread() != NULL) os::free_thread(osthread());
375
376 delete _SR_lock;
377
378 // clear thread local storage if the Thread is deleting itself
379 if (this == Thread::current()) {
380 ThreadLocalStorage::set_thread(NULL);
381 } else {
382 // In the case where we're not the current thread, invalidate all the
383 // caches in case some code tries to get the current thread or the
384 // thread that was destroyed, and gets stale information.
385 ThreadLocalStorage::invalidate_all();
386 }
387 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
388 }
389
390 // NOTE: dummy function for assertion purpose.
391 void Thread::run() {
392 ShouldNotReachHere();
393 }
394
395 #ifdef ASSERT
396 // Private method to check for dangling thread pointer
397 void check_for_dangling_thread_pointer(Thread *thread) {
398 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
399 "possibility of dangling Thread pointer");
400 }
401 #endif
402
403
404 #ifndef PRODUCT
405 // Tracing method for basic thread operations
406 void Thread::trace(const char* msg, const Thread* const thread) {
407 if (!TraceThreadEvents) return;
408 ResourceMark rm;
409 ThreadCritical tc;
410 const char *name = "non-Java thread";
411 int prio = -1;
412 if (thread->is_Java_thread()
413 && !thread->is_Compiler_thread()) {
414 // The Threads_lock must be held to get information about
415 // this thread but may not be in some situations when
416 // tracing thread events.
417 bool release_Threads_lock = false;
418 if (!Threads_lock->owned_by_self()) {
419 Threads_lock->lock();
420 release_Threads_lock = true;
421 }
422 JavaThread* jt = (JavaThread *)thread;
423 name = (char *)jt->get_thread_name();
424 oop thread_oop = jt->threadObj();
425 if (thread_oop != NULL) {
426 prio = java_lang_Thread::priority(thread_oop);
427 }
428 if (release_Threads_lock) {
429 Threads_lock->unlock();
430 }
431 }
432 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
433 }
434 #endif
435
436
437 ThreadPriority Thread::get_priority(const Thread* const thread) {
438 trace("get priority", thread);
439 ThreadPriority priority;
440 // Can return an error!
441 (void)os::get_priority(thread, priority);
442 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
443 return priority;
444 }
445
446 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
447 trace("set priority", thread);
448 debug_only(check_for_dangling_thread_pointer(thread);)
449 // Can return an error!
450 (void)os::set_priority(thread, priority);
451 }
452
453
454 void Thread::start(Thread* thread) {
455 trace("start", thread);
456 // Start is different from resume in that its safety is guaranteed by context or
457 // being called from a Java method synchronized on the Thread object.
458 if (!DisableStartThread) {
459 if (thread->is_Java_thread()) {
460 // Initialize the thread state to RUNNABLE before starting this thread.
461 // Can not set it after the thread started because we do not know the
462 // exact thread state at that time. It could be in MONITOR_WAIT or
463 // in SLEEPING or some other state.
464 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
465 java_lang_Thread::RUNNABLE);
466 }
467 os::start_thread(thread);
468 }
469 }
470
471 // Enqueue a VM_Operation to do the job for us - sometime later
472 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
473 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
474 VMThread::execute(vm_stop);
475 }
476
477
478 //
479 // Check if an external suspend request has completed (or has been
480 // cancelled). Returns true if the thread is externally suspended and
481 // false otherwise.
482 //
483 // The bits parameter returns information about the code path through
484 // the routine. Useful for debugging:
485 //
486 // set in is_ext_suspend_completed():
487 // 0x00000001 - routine was entered
488 // 0x00000010 - routine return false at end
489 // 0x00000100 - thread exited (return false)
490 // 0x00000200 - suspend request cancelled (return false)
491 // 0x00000400 - thread suspended (return true)
492 // 0x00001000 - thread is in a suspend equivalent state (return true)
493 // 0x00002000 - thread is native and walkable (return true)
494 // 0x00004000 - thread is native_trans and walkable (needed retry)
495 //
496 // set in wait_for_ext_suspend_completion():
497 // 0x00010000 - routine was entered
498 // 0x00020000 - suspend request cancelled before loop (return false)
499 // 0x00040000 - thread suspended before loop (return true)
500 // 0x00080000 - suspend request cancelled in loop (return false)
501 // 0x00100000 - thread suspended in loop (return true)
502 // 0x00200000 - suspend not completed during retry loop (return false)
503 //
504
505 // Helper class for tracing suspend wait debug bits.
506 //
507 // 0x00000100 indicates that the target thread exited before it could
508 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
509 // 0x00080000 each indicate a cancelled suspend request so they don't
510 // count as wait failures either.
511 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
512
513 class TraceSuspendDebugBits : public StackObj {
514 private:
515 JavaThread * jt;
516 bool is_wait;
517 bool called_by_wait; // meaningful when !is_wait
518 uint32_t * bits;
519
520 public:
521 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
522 uint32_t *_bits) {
523 jt = _jt;
524 is_wait = _is_wait;
525 called_by_wait = _called_by_wait;
526 bits = _bits;
527 }
528
529 ~TraceSuspendDebugBits() {
530 if (!is_wait) {
531 #if 1
532 // By default, don't trace bits for is_ext_suspend_completed() calls.
533 // That trace is very chatty.
534 return;
535 #else
536 if (!called_by_wait) {
537 // If tracing for is_ext_suspend_completed() is enabled, then only
538 // trace calls to it from wait_for_ext_suspend_completion()
539 return;
540 }
541 #endif
542 }
543
544 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
545 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
546 MutexLocker ml(Threads_lock); // needed for get_thread_name()
547 ResourceMark rm;
548
549 tty->print_cr(
550 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
551 jt->get_thread_name(), *bits);
552
553 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
554 }
555 }
556 }
557 };
558 #undef DEBUG_FALSE_BITS
559
560
561 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
562 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
563
564 bool did_trans_retry = false; // only do thread_in_native_trans retry once
565 bool do_trans_retry; // flag to force the retry
566
567 *bits |= 0x00000001;
568
569 do {
570 do_trans_retry = false;
571
572 if (is_exiting()) {
573 // Thread is in the process of exiting. This is always checked
574 // first to reduce the risk of dereferencing a freed JavaThread.
575 *bits |= 0x00000100;
576 return false;
577 }
578
579 if (!is_external_suspend()) {
580 // Suspend request is cancelled. This is always checked before
581 // is_ext_suspended() to reduce the risk of a rogue resume
582 // confusing the thread that made the suspend request.
583 *bits |= 0x00000200;
584 return false;
585 }
586
587 if (is_ext_suspended()) {
588 // thread is suspended
589 *bits |= 0x00000400;
590 return true;
591 }
592
593 // Now that we no longer do hard suspends of threads running
594 // native code, the target thread can be changing thread state
595 // while we are in this routine:
596 //
597 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
598 //
599 // We save a copy of the thread state as observed at this moment
600 // and make our decision about suspend completeness based on the
601 // copy. This closes the race where the thread state is seen as
602 // _thread_in_native_trans in the if-thread_blocked check, but is
603 // seen as _thread_blocked in if-thread_in_native_trans check.
604 JavaThreadState save_state = thread_state();
605
606 if (save_state == _thread_blocked && is_suspend_equivalent()) {
607 // If the thread's state is _thread_blocked and this blocking
608 // condition is known to be equivalent to a suspend, then we can
609 // consider the thread to be externally suspended. This means that
610 // the code that sets _thread_blocked has been modified to do
611 // self-suspension if the blocking condition releases. We also
612 // used to check for CONDVAR_WAIT here, but that is now covered by
613 // the _thread_blocked with self-suspension check.
614 //
615 // Return true since we wouldn't be here unless there was still an
616 // external suspend request.
617 *bits |= 0x00001000;
618 return true;
619 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
620 // Threads running native code will self-suspend on native==>VM/Java
621 // transitions. If its stack is walkable (should always be the case
622 // unless this function is called before the actual java_suspend()
623 // call), then the wait is done.
624 *bits |= 0x00002000;
625 return true;
626 } else if (!called_by_wait && !did_trans_retry &&
627 save_state == _thread_in_native_trans &&
628 frame_anchor()->walkable()) {
629 // The thread is transitioning from thread_in_native to another
630 // thread state. check_safepoint_and_suspend_for_native_trans()
631 // will force the thread to self-suspend. If it hasn't gotten
632 // there yet we may have caught the thread in-between the native
633 // code check above and the self-suspend. Lucky us. If we were
634 // called by wait_for_ext_suspend_completion(), then it
635 // will be doing the retries so we don't have to.
636 //
637 // Since we use the saved thread state in the if-statement above,
638 // there is a chance that the thread has already transitioned to
639 // _thread_blocked by the time we get here. In that case, we will
640 // make a single unnecessary pass through the logic below. This
641 // doesn't hurt anything since we still do the trans retry.
642
643 *bits |= 0x00004000;
644
645 // Once the thread leaves thread_in_native_trans for another
646 // thread state, we break out of this retry loop. We shouldn't
647 // need this flag to prevent us from getting back here, but
648 // sometimes paranoia is good.
649 did_trans_retry = true;
650
651 // We wait for the thread to transition to a more usable state.
652 for (int i = 1; i <= SuspendRetryCount; i++) {
653 // We used to do an "os::yield_all(i)" call here with the intention
654 // that yielding would increase on each retry. However, the parameter
655 // is ignored on Linux which means the yield didn't scale up. Waiting
656 // on the SR_lock below provides a much more predictable scale up for
657 // the delay. It also provides a simple/direct point to check for any
658 // safepoint requests from the VMThread
659
660 // temporarily drops SR_lock while doing wait with safepoint check
661 // (if we're a JavaThread - the WatcherThread can also call this)
662 // and increase delay with each retry
663 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
664
665 // check the actual thread state instead of what we saved above
666 if (thread_state() != _thread_in_native_trans) {
667 // the thread has transitioned to another thread state so
668 // try all the checks (except this one) one more time.
669 do_trans_retry = true;
670 break;
671 }
672 } // end retry loop
673
674
675 }
676 } while (do_trans_retry);
677
678 *bits |= 0x00000010;
679 return false;
680 }
681
682 //
683 // Wait for an external suspend request to complete (or be cancelled).
684 // Returns true if the thread is externally suspended and false otherwise.
685 //
686 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
687 uint32_t *bits) {
688 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
689 false /* !called_by_wait */, bits);
690
691 // local flag copies to minimize SR_lock hold time
692 bool is_suspended;
693 bool pending;
694 uint32_t reset_bits;
695
696 // set a marker so is_ext_suspend_completed() knows we are the caller
697 *bits |= 0x00010000;
698
699 // We use reset_bits to reinitialize the bits value at the top of
700 // each retry loop. This allows the caller to make use of any
701 // unused bits for their own marking purposes.
702 reset_bits = *bits;
703
704 {
705 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
706 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
707 delay, bits);
708 pending = is_external_suspend();
709 }
710 // must release SR_lock to allow suspension to complete
711
712 if (!pending) {
713 // A cancelled suspend request is the only false return from
714 // is_ext_suspend_completed() that keeps us from entering the
715 // retry loop.
716 *bits |= 0x00020000;
717 return false;
718 }
719
720 if (is_suspended) {
721 *bits |= 0x00040000;
722 return true;
723 }
724
725 for (int i = 1; i <= retries; i++) {
726 *bits = reset_bits; // reinit to only track last retry
727
728 // We used to do an "os::yield_all(i)" call here with the intention
729 // that yielding would increase on each retry. However, the parameter
730 // is ignored on Linux which means the yield didn't scale up. Waiting
731 // on the SR_lock below provides a much more predictable scale up for
732 // the delay. It also provides a simple/direct point to check for any
733 // safepoint requests from the VMThread
734
735 {
736 MutexLocker ml(SR_lock());
737 // wait with safepoint check (if we're a JavaThread - the WatcherThread
738 // can also call this) and increase delay with each retry
739 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
740
741 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
742 delay, bits);
743
744 // It is possible for the external suspend request to be cancelled
745 // (by a resume) before the actual suspend operation is completed.
746 // Refresh our local copy to see if we still need to wait.
747 pending = is_external_suspend();
748 }
749
750 if (!pending) {
751 // A cancelled suspend request is the only false return from
752 // is_ext_suspend_completed() that keeps us from staying in the
753 // retry loop.
754 *bits |= 0x00080000;
755 return false;
756 }
757
758 if (is_suspended) {
759 *bits |= 0x00100000;
760 return true;
761 }
762 } // end retry loop
763
764 // thread did not suspend after all our retries
765 *bits |= 0x00200000;
766 return false;
767 }
768
769 #ifndef PRODUCT
770 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
771
772 // This should not need to be atomic as the only way for simultaneous
773 // updates is via interrupts. Even then this should be rare or non-existant
774 // and we don't care that much anyway.
775
776 int index = _jmp_ring_index;
777 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
778 _jmp_ring[index]._target = (intptr_t) target;
779 _jmp_ring[index]._instruction = (intptr_t) instr;
780 _jmp_ring[index]._file = file;
781 _jmp_ring[index]._line = line;
782 }
783 #endif /* PRODUCT */
784
785 // Called by flat profiler
786 // Callers have already called wait_for_ext_suspend_completion
787 // The assertion for that is currently too complex to put here:
788 bool JavaThread::profile_last_Java_frame(frame* _fr) {
789 bool gotframe = false;
790 // self suspension saves needed state.
791 if (has_last_Java_frame() && _anchor.walkable()) {
792 *_fr = pd_last_frame();
793 gotframe = true;
794 }
795 return gotframe;
796 }
797
798 void Thread::interrupt(Thread* thread) {
799 trace("interrupt", thread);
800 debug_only(check_for_dangling_thread_pointer(thread);)
801 os::interrupt(thread);
802 }
803
804 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
805 trace("is_interrupted", thread);
806 debug_only(check_for_dangling_thread_pointer(thread);)
807 // Note: If clear_interrupted==false, this simply fetches and
808 // returns the value of the field osthread()->interrupted().
809 return os::is_interrupted(thread, clear_interrupted);
810 }
811
812
813 // GC Support
814 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
815 jint thread_parity = _oops_do_parity;
816 if (thread_parity != strong_roots_parity) {
817 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
818 if (res == thread_parity) {
819 return true;
820 } else {
821 guarantee(res == strong_roots_parity, "Or else what?");
822 assert(SharedHeap::heap()->workers()->active_workers() > 0,
823 "Should only fail when parallel.");
824 return false;
825 }
826 }
827 assert(SharedHeap::heap()->workers()->active_workers() > 0,
828 "Should only fail when parallel.");
829 return false;
830 }
831
832 void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
833 active_handles()->oops_do(f);
834 // Do oop for ThreadShadow
835 f->do_oop((oop*)&_pending_exception);
836 handle_area()->oops_do(f);
837 }
838
839 void Thread::nmethods_do(CodeBlobClosure* cf) {
840 // no nmethods in a generic thread...
841 }
842
843 void Thread::metadata_do(void f(Metadata*)) {
844 if (metadata_handles() != NULL) {
845 for (int i = 0; i< metadata_handles()->length(); i++) {
846 f(metadata_handles()->at(i));
847 }
848 }
849 }
850
851 void Thread::print_on(outputStream* st) const {
852 // get_priority assumes osthread initialized
853 if (osthread() != NULL) {
854 int os_prio;
855 if (os::get_native_priority(this, &os_prio) == OS_OK) {
856 st->print("os_prio=%d ", os_prio);
857 }
858 st->print("tid=" INTPTR_FORMAT " ", this);
859 osthread()->print_on(st);
860 }
861 debug_only(if (WizardMode) print_owned_locks_on(st);)
862 }
863
864 // Thread::print_on_error() is called by fatal error handler. Don't use
865 // any lock or allocate memory.
866 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
867 if (is_VM_thread()) st->print("VMThread");
868 else if (is_Compiler_thread()) st->print("CompilerThread");
869 else if (is_Java_thread()) st->print("JavaThread");
870 else if (is_GC_task_thread()) st->print("GCTaskThread");
871 else if (is_Watcher_thread()) st->print("WatcherThread");
872 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
873 else st->print("Thread");
874
875 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
876 _stack_base - _stack_size, _stack_base);
877
878 if (osthread()) {
879 st->print(" [id=%d]", osthread()->thread_id());
880 }
881 }
882
883 #ifdef ASSERT
884 void Thread::print_owned_locks_on(outputStream* st) const {
885 Monitor *cur = _owned_locks;
886 if (cur == NULL) {
887 st->print(" (no locks) ");
888 } else {
889 st->print_cr(" Locks owned:");
890 while(cur) {
891 cur->print_on(st);
892 cur = cur->next();
893 }
894 }
895 }
896
897 static int ref_use_count = 0;
898
899 bool Thread::owns_locks_but_compiled_lock() const {
900 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
901 if (cur != Compile_lock) return true;
902 }
903 return false;
904 }
905
906
907 #endif
908
909 #ifndef PRODUCT
910
911 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
912 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
913 // no threads which allow_vm_block's are held
914 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
915 // Check if current thread is allowed to block at a safepoint
916 if (!(_allow_safepoint_count == 0))
917 fatal("Possible safepoint reached by thread that does not allow it");
918 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
919 fatal("LEAF method calling lock?");
920 }
921
922 #ifdef ASSERT
923 if (potential_vm_operation && is_Java_thread()
924 && !Universe::is_bootstrapping()) {
925 // Make sure we do not hold any locks that the VM thread also uses.
926 // This could potentially lead to deadlocks
927 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
928 // Threads_lock is special, since the safepoint synchronization will not start before this is
929 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
930 // since it is used to transfer control between JavaThreads and the VMThread
931 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
932 if ( (cur->allow_vm_block() &&
933 cur != Threads_lock &&
934 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
935 cur != VMOperationRequest_lock &&
936 cur != VMOperationQueue_lock) ||
937 cur->rank() == Mutex::special) {
938 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
939 }
940 }
941 }
942
943 if (GCALotAtAllSafepoints) {
944 // We could enter a safepoint here and thus have a gc
945 InterfaceSupport::check_gc_alot();
946 }
947 #endif
948 }
949 #endif
950
951 bool Thread::is_in_stack(address adr) const {
952 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
953 address end = os::current_stack_pointer();
954 // Allow non Java threads to call this without stack_base
955 if (_stack_base == NULL) return true;
956 if (stack_base() >= adr && adr >= end) return true;
957
958 return false;
959 }
960
961
962 bool Thread::is_in_usable_stack(address adr) const {
963 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
964 size_t usable_stack_size = _stack_size - stack_guard_size;
965
966 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
967 }
968
969
970 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
971 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
972 // used for compilation in the future. If that change is made, the need for these methods
973 // should be revisited, and they should be removed if possible.
974
975 bool Thread::is_lock_owned(address adr) const {
976 return on_local_stack(adr);
977 }
978
979 bool Thread::set_as_starting_thread() {
980 // NOTE: this must be called inside the main thread.
981 return os::create_main_thread((JavaThread*)this);
982 }
983
984 static void initialize_class(Symbol* class_name, TRAPS) {
985 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
986 InstanceKlass::cast(klass)->initialize(CHECK);
987 }
988
989
990 // Creates the initial ThreadGroup
991 static Handle create_initial_thread_group(TRAPS) {
992 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
993 instanceKlassHandle klass (THREAD, k);
994
995 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
996 {
997 JavaValue result(T_VOID);
998 JavaCalls::call_special(&result,
999 system_instance,
1000 klass,
1001 vmSymbols::object_initializer_name(),
1002 vmSymbols::void_method_signature(),
1003 CHECK_NH);
1004 }
1005 Universe::set_system_thread_group(system_instance());
1006
1007 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1008 {
1009 JavaValue result(T_VOID);
1010 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1011 JavaCalls::call_special(&result,
1012 main_instance,
1013 klass,
1014 vmSymbols::object_initializer_name(),
1015 vmSymbols::threadgroup_string_void_signature(),
1016 system_instance,
1017 string,
1018 CHECK_NH);
1019 }
1020 return main_instance;
1021 }
1022
1023 // Creates the initial Thread
1024 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1025 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1026 instanceKlassHandle klass (THREAD, k);
1027 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1028
1029 java_lang_Thread::set_thread(thread_oop(), thread);
1030 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1031 thread->set_threadObj(thread_oop());
1032
1033 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1034
1035 JavaValue result(T_VOID);
1036 JavaCalls::call_special(&result, thread_oop,
1037 klass,
1038 vmSymbols::object_initializer_name(),
1039 vmSymbols::threadgroup_string_void_signature(),
1040 thread_group,
1041 string,
1042 CHECK_NULL);
1043 return thread_oop();
1044 }
1045
1046 static void call_initializeSystemClass(TRAPS) {
1047 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1048 instanceKlassHandle klass (THREAD, k);
1049
1050 JavaValue result(T_VOID);
1051 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1052 vmSymbols::void_method_signature(), CHECK);
1053 }
1054
1055 char java_runtime_name[128] = "";
1056 char java_runtime_version[128] = "";
1057
1058 // extract the JRE name from sun.misc.Version.java_runtime_name
1059 static const char* get_java_runtime_name(TRAPS) {
1060 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1061 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1062 fieldDescriptor fd;
1063 bool found = k != NULL &&
1064 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1065 vmSymbols::string_signature(), &fd);
1066 if (found) {
1067 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1068 if (name_oop == NULL)
1069 return NULL;
1070 const char* name = java_lang_String::as_utf8_string(name_oop,
1071 java_runtime_name,
1072 sizeof(java_runtime_name));
1073 return name;
1074 } else {
1075 return NULL;
1076 }
1077 }
1078
1079 // extract the JRE version from sun.misc.Version.java_runtime_version
1080 static const char* get_java_runtime_version(TRAPS) {
1081 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1082 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1083 fieldDescriptor fd;
1084 bool found = k != NULL &&
1085 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1086 vmSymbols::string_signature(), &fd);
1087 if (found) {
1088 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1089 if (name_oop == NULL)
1090 return NULL;
1091 const char* name = java_lang_String::as_utf8_string(name_oop,
1092 java_runtime_version,
1093 sizeof(java_runtime_version));
1094 return name;
1095 } else {
1096 return NULL;
1097 }
1098 }
1099
1100 // General purpose hook into Java code, run once when the VM is initialized.
1101 // The Java library method itself may be changed independently from the VM.
1102 static void call_postVMInitHook(TRAPS) {
1103 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1104 instanceKlassHandle klass (THREAD, k);
1105 if (klass.not_null()) {
1106 JavaValue result(T_VOID);
1107 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1108 vmSymbols::void_method_signature(),
1109 CHECK);
1110 }
1111 }
1112
1113 static void reset_vm_info_property(TRAPS) {
1114 // the vm info string
1115 ResourceMark rm(THREAD);
1116 const char *vm_info = VM_Version::vm_info_string();
1117
1118 // java.lang.System class
1119 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1120 instanceKlassHandle klass (THREAD, k);
1121
1122 // setProperty arguments
1123 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1124 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1125
1126 // return value
1127 JavaValue r(T_OBJECT);
1128
1129 // public static String setProperty(String key, String value);
1130 JavaCalls::call_static(&r,
1131 klass,
1132 vmSymbols::setProperty_name(),
1133 vmSymbols::string_string_string_signature(),
1134 key_str,
1135 value_str,
1136 CHECK);
1137 }
1138
1139
1140 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1141 assert(thread_group.not_null(), "thread group should be specified");
1142 assert(threadObj() == NULL, "should only create Java thread object once");
1143
1144 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1145 instanceKlassHandle klass (THREAD, k);
1146 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1147
1148 java_lang_Thread::set_thread(thread_oop(), this);
1149 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1150 set_threadObj(thread_oop());
1151
1152 JavaValue result(T_VOID);
1153 if (thread_name != NULL) {
1154 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1155 // Thread gets assigned specified name and null target
1156 JavaCalls::call_special(&result,
1157 thread_oop,
1158 klass,
1159 vmSymbols::object_initializer_name(),
1160 vmSymbols::threadgroup_string_void_signature(),
1161 thread_group, // Argument 1
1162 name, // Argument 2
1163 THREAD);
1164 } else {
1165 // Thread gets assigned name "Thread-nnn" and null target
1166 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1167 JavaCalls::call_special(&result,
1168 thread_oop,
1169 klass,
1170 vmSymbols::object_initializer_name(),
1171 vmSymbols::threadgroup_runnable_void_signature(),
1172 thread_group, // Argument 1
1173 Handle(), // Argument 2
1174 THREAD);
1175 }
1176
1177
1178 if (daemon) {
1179 java_lang_Thread::set_daemon(thread_oop());
1180 }
1181
1182 if (HAS_PENDING_EXCEPTION) {
1183 return;
1184 }
1185
1186 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1187 Handle threadObj(this, this->threadObj());
1188
1189 JavaCalls::call_special(&result,
1190 thread_group,
1191 group,
1192 vmSymbols::add_method_name(),
1193 vmSymbols::thread_void_signature(),
1194 threadObj, // Arg 1
1195 THREAD);
1196
1197
1198 }
1199
1200 // NamedThread -- non-JavaThread subclasses with multiple
1201 // uniquely named instances should derive from this.
1202 NamedThread::NamedThread() : Thread() {
1203 _name = NULL;
1204 _processed_thread = NULL;
1205 }
1206
1207 NamedThread::~NamedThread() {
1208 if (_name != NULL) {
1209 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1210 _name = NULL;
1211 }
1212 }
1213
1214 void NamedThread::set_name(const char* format, ...) {
1215 guarantee(_name == NULL, "Only get to set name once.");
1216 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1217 guarantee(_name != NULL, "alloc failure");
1218 va_list ap;
1219 va_start(ap, format);
1220 jio_vsnprintf(_name, max_name_len, format, ap);
1221 va_end(ap);
1222 }
1223
1224 // ======= WatcherThread ========
1225
1226 // The watcher thread exists to simulate timer interrupts. It should
1227 // be replaced by an abstraction over whatever native support for
1228 // timer interrupts exists on the platform.
1229
1230 WatcherThread* WatcherThread::_watcher_thread = NULL;
1231 bool WatcherThread::_startable = false;
1232 volatile bool WatcherThread::_should_terminate = false;
1233
1234 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1235 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1236 if (os::create_thread(this, os::watcher_thread)) {
1237 _watcher_thread = this;
1238
1239 // Set the watcher thread to the highest OS priority which should not be
1240 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1241 // is created. The only normal thread using this priority is the reference
1242 // handler thread, which runs for very short intervals only.
1243 // If the VMThread's priority is not lower than the WatcherThread profiling
1244 // will be inaccurate.
1245 os::set_priority(this, MaxPriority);
1246 if (!DisableStartThread) {
1247 os::start_thread(this);
1248 }
1249 }
1250 }
1251
1252 int WatcherThread::sleep() const {
1253 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1254
1255 // remaining will be zero if there are no tasks,
1256 // causing the WatcherThread to sleep until a task is
1257 // enrolled
1258 int remaining = PeriodicTask::time_to_wait();
1259 int time_slept = 0;
1260
1261 // we expect this to timeout - we only ever get unparked when
1262 // we should terminate or when a new task has been enrolled
1263 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1264
1265 jlong time_before_loop = os::javaTimeNanos();
1266
1267 for (;;) {
1268 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1269 jlong now = os::javaTimeNanos();
1270
1271 if (remaining == 0) {
1272 // if we didn't have any tasks we could have waited for a long time
1273 // consider the time_slept zero and reset time_before_loop
1274 time_slept = 0;
1275 time_before_loop = now;
1276 } else {
1277 // need to recalulate since we might have new tasks in _tasks
1278 time_slept = (int) ((now - time_before_loop) / 1000000);
1279 }
1280
1281 // Change to task list or spurious wakeup of some kind
1282 if (timedout || _should_terminate) {
1283 break;
1284 }
1285
1286 remaining = PeriodicTask::time_to_wait();
1287 if (remaining == 0) {
1288 // Last task was just disenrolled so loop around and wait until
1289 // another task gets enrolled
1290 continue;
1291 }
1292
1293 remaining -= time_slept;
1294 if (remaining <= 0)
1295 break;
1296 }
1297
1298 return time_slept;
1299 }
1300
1301 void WatcherThread::run() {
1302 assert(this == watcher_thread(), "just checking");
1303
1304 this->record_stack_base_and_size();
1305 this->initialize_thread_local_storage();
1306 this->set_active_handles(JNIHandleBlock::allocate_block());
1307 while(!_should_terminate) {
1308 assert(watcher_thread() == Thread::current(), "thread consistency check");
1309 assert(watcher_thread() == this, "thread consistency check");
1310
1311 // Calculate how long it'll be until the next PeriodicTask work
1312 // should be done, and sleep that amount of time.
1313 int time_waited = sleep();
1314
1315 if (is_error_reported()) {
1316 // A fatal error has happened, the error handler(VMError::report_and_die)
1317 // should abort JVM after creating an error log file. However in some
1318 // rare cases, the error handler itself might deadlock. Here we try to
1319 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1320 //
1321 // This code is in WatcherThread because WatcherThread wakes up
1322 // periodically so the fatal error handler doesn't need to do anything;
1323 // also because the WatcherThread is less likely to crash than other
1324 // threads.
1325
1326 for (;;) {
1327 if (!ShowMessageBoxOnError
1328 && (OnError == NULL || OnError[0] == '\0')
1329 && Arguments::abort_hook() == NULL) {
1330 os::sleep(this, 2 * 60 * 1000, false);
1331 fdStream err(defaultStream::output_fd());
1332 err.print_raw_cr("# [ timer expired, abort... ]");
1333 // skip atexit/vm_exit/vm_abort hooks
1334 os::die();
1335 }
1336
1337 // Wake up 5 seconds later, the fatal handler may reset OnError or
1338 // ShowMessageBoxOnError when it is ready to abort.
1339 os::sleep(this, 5 * 1000, false);
1340 }
1341 }
1342
1343 PeriodicTask::real_time_tick(time_waited);
1344 }
1345
1346 // Signal that it is terminated
1347 {
1348 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1349 _watcher_thread = NULL;
1350 Terminator_lock->notify();
1351 }
1352
1353 // Thread destructor usually does this..
1354 ThreadLocalStorage::set_thread(NULL);
1355 }
1356
1357 void WatcherThread::start() {
1358 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1359
1360 if (watcher_thread() == NULL && _startable) {
1361 _should_terminate = false;
1362 // Create the single instance of WatcherThread
1363 new WatcherThread();
1364 }
1365 }
1366
1367 void WatcherThread::make_startable() {
1368 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1369 _startable = true;
1370 }
1371
1372 void WatcherThread::stop() {
1373 {
1374 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1375 _should_terminate = true;
1376 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1377
1378 WatcherThread* watcher = watcher_thread();
1379 if (watcher != NULL)
1380 watcher->unpark();
1381 }
1382
1383 // it is ok to take late safepoints here, if needed
1384 MutexLocker mu(Terminator_lock);
1385
1386 while(watcher_thread() != NULL) {
1387 // This wait should make safepoint checks, wait without a timeout,
1388 // and wait as a suspend-equivalent condition.
1389 //
1390 // Note: If the FlatProfiler is running, then this thread is waiting
1391 // for the WatcherThread to terminate and the WatcherThread, via the
1392 // FlatProfiler task, is waiting for the external suspend request on
1393 // this thread to complete. wait_for_ext_suspend_completion() will
1394 // eventually timeout, but that takes time. Making this wait a
1395 // suspend-equivalent condition solves that timeout problem.
1396 //
1397 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1398 Mutex::_as_suspend_equivalent_flag);
1399 }
1400 }
1401
1402 void WatcherThread::unpark() {
1403 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1404 PeriodicTask_lock->notify();
1405 }
1406
1407 void WatcherThread::print_on(outputStream* st) const {
1408 st->print("\"%s\" ", name());
1409 Thread::print_on(st);
1410 st->cr();
1411 }
1412
1413 // ======= JavaThread ========
1414
1415 // A JavaThread is a normal Java thread
1416
1417 void JavaThread::initialize() {
1418 // Initialize fields
1419
1420 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1421 set_claimed_par_id(-1);
1422
1423 set_saved_exception_pc(NULL);
1424 set_threadObj(NULL);
1425 _anchor.clear();
1426 set_entry_point(NULL);
1427 set_jni_functions(jni_functions());
1428 set_callee_target(NULL);
1429 set_vm_result(NULL);
1430 set_vm_result_2(NULL);
1431 set_vframe_array_head(NULL);
1432 set_vframe_array_last(NULL);
1433 set_deferred_locals(NULL);
1434 set_deopt_mark(NULL);
1435 set_deopt_nmethod(NULL);
1436 clear_must_deopt_id();
1437 set_monitor_chunks(NULL);
1438 set_next(NULL);
1439 set_thread_state(_thread_new);
1440 #if INCLUDE_NMT
1441 set_recorder(NULL);
1442 #endif
1443 _terminated = _not_terminated;
1444 _privileged_stack_top = NULL;
1445 _array_for_gc = NULL;
1446 _suspend_equivalent = false;
1447 _in_deopt_handler = 0;
1448 _doing_unsafe_access = false;
1449 _stack_guard_state = stack_guard_unused;
1450 (void)const_cast<oop&>(_exception_oop = NULL);
1451 _exception_pc = 0;
1452 _exception_handler_pc = 0;
1453 _is_method_handle_return = 0;
1454 _jvmti_thread_state= NULL;
1455 _should_post_on_exceptions_flag = JNI_FALSE;
1456 _jvmti_get_loaded_classes_closure = NULL;
1457 _interp_only_mode = 0;
1458 _special_runtime_exit_condition = _no_async_condition;
1459 _pending_async_exception = NULL;
1460 _thread_stat = NULL;
1461 _thread_stat = new ThreadStatistics();
1462 _blocked_on_compilation = false;
1463 _jni_active_critical = 0;
1464 _do_not_unlock_if_synchronized = false;
1465 _cached_monitor_info = NULL;
1466 _parker = Parker::Allocate(this) ;
1467
1468 #ifndef PRODUCT
1469 _jmp_ring_index = 0;
1470 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1471 record_jump(NULL, NULL, NULL, 0);
1472 }
1473 #endif /* PRODUCT */
1474
1475 set_thread_profiler(NULL);
1476 if (FlatProfiler::is_active()) {
1477 // This is where we would decide to either give each thread it's own profiler
1478 // or use one global one from FlatProfiler,
1479 // or up to some count of the number of profiled threads, etc.
1480 ThreadProfiler* pp = new ThreadProfiler();
1481 pp->engage();
1482 set_thread_profiler(pp);
1483 }
1484
1485 // Setup safepoint state info for this thread
1486 ThreadSafepointState::create(this);
1487
1488 debug_only(_java_call_counter = 0);
1489
1490 // JVMTI PopFrame support
1491 _popframe_condition = popframe_inactive;
1492 _popframe_preserved_args = NULL;
1493 _popframe_preserved_args_size = 0;
1494
1495 pd_initialize();
1496 }
1497
1498 #if INCLUDE_ALL_GCS
1499 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1500 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1501 #endif // INCLUDE_ALL_GCS
1502
1503 JavaThread::JavaThread(bool is_attaching_via_jni) :
1504 Thread()
1505 #if INCLUDE_ALL_GCS
1506 , _satb_mark_queue(&_satb_mark_queue_set),
1507 _dirty_card_queue(&_dirty_card_queue_set)
1508 #endif // INCLUDE_ALL_GCS
1509 {
1510 initialize();
1511 if (is_attaching_via_jni) {
1512 _jni_attach_state = _attaching_via_jni;
1513 } else {
1514 _jni_attach_state = _not_attaching_via_jni;
1515 }
1516 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1517 _safepoint_visible = false;
1518 }
1519
1520 bool JavaThread::reguard_stack(address cur_sp) {
1521 if (_stack_guard_state != stack_guard_yellow_disabled) {
1522 return true; // Stack already guarded or guard pages not needed.
1523 }
1524
1525 if (register_stack_overflow()) {
1526 // For those architectures which have separate register and
1527 // memory stacks, we must check the register stack to see if
1528 // it has overflowed.
1529 return false;
1530 }
1531
1532 // Java code never executes within the yellow zone: the latter is only
1533 // there to provoke an exception during stack banging. If java code
1534 // is executing there, either StackShadowPages should be larger, or
1535 // some exception code in c1, c2 or the interpreter isn't unwinding
1536 // when it should.
1537 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1538
1539 enable_stack_yellow_zone();
1540 return true;
1541 }
1542
1543 bool JavaThread::reguard_stack(void) {
1544 return reguard_stack(os::current_stack_pointer());
1545 }
1546
1547
1548 void JavaThread::block_if_vm_exited() {
1549 if (_terminated == _vm_exited) {
1550 // _vm_exited is set at safepoint, and Threads_lock is never released
1551 // we will block here forever
1552 Threads_lock->lock_without_safepoint_check();
1553 ShouldNotReachHere();
1554 }
1555 }
1556
1557
1558 // Remove this ifdef when C1 is ported to the compiler interface.
1559 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1560
1561 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1562 Thread()
1563 #if INCLUDE_ALL_GCS
1564 , _satb_mark_queue(&_satb_mark_queue_set),
1565 _dirty_card_queue(&_dirty_card_queue_set)
1566 #endif // INCLUDE_ALL_GCS
1567 {
1568 if (TraceThreadEvents) {
1569 tty->print_cr("creating thread %p", this);
1570 }
1571 initialize();
1572 _jni_attach_state = _not_attaching_via_jni;
1573 set_entry_point(entry_point);
1574 // Create the native thread itself.
1575 // %note runtime_23
1576 os::ThreadType thr_type = os::java_thread;
1577 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1578 os::java_thread;
1579 os::create_thread(this, thr_type, stack_sz);
1580 _safepoint_visible = false;
1581 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1582 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1583 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1584 // the exception consists of creating the exception object & initializing it, initialization
1585 // will leave the VM via a JavaCall and then all locks must be unlocked).
1586 //
1587 // The thread is still suspended when we reach here. Thread must be explicit started
1588 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1589 // by calling Threads:add. The reason why this is not done here, is because the thread
1590 // object must be fully initialized (take a look at JVM_Start)
1591 }
1592
1593 JavaThread::~JavaThread() {
1594 if (TraceThreadEvents) {
1595 tty->print_cr("terminate thread %p", this);
1596 }
1597
1598 // By now, this thread should already be invisible to safepoint,
1599 // and its per-thread recorder also collected.
1600 assert(!is_safepoint_visible(), "wrong state");
1601 #if INCLUDE_NMT
1602 assert(get_recorder() == NULL, "Already collected");
1603 #endif // INCLUDE_NMT
1604
1605 // JSR166 -- return the parker to the free list
1606 Parker::Release(_parker);
1607 _parker = NULL ;
1608
1609 // Free any remaining previous UnrollBlock
1610 vframeArray* old_array = vframe_array_last();
1611
1612 if (old_array != NULL) {
1613 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1614 old_array->set_unroll_block(NULL);
1615 delete old_info;
1616 delete old_array;
1617 }
1618
1619 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1620 if (deferred != NULL) {
1621 // This can only happen if thread is destroyed before deoptimization occurs.
1622 assert(deferred->length() != 0, "empty array!");
1623 do {
1624 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1625 deferred->remove_at(0);
1626 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1627 delete dlv;
1628 } while (deferred->length() != 0);
1629 delete deferred;
1630 }
1631
1632 // All Java related clean up happens in exit
1633 ThreadSafepointState::destroy(this);
1634 if (_thread_profiler != NULL) delete _thread_profiler;
1635 if (_thread_stat != NULL) delete _thread_stat;
1636 }
1637
1638
1639 // The first routine called by a new Java thread
1640 void JavaThread::run() {
1641 // initialize thread-local alloc buffer related fields
1642 this->initialize_tlab();
1643
1644 // used to test validitity of stack trace backs
1645 this->record_base_of_stack_pointer();
1646
1647 // Record real stack base and size.
1648 this->record_stack_base_and_size();
1649
1650 // Initialize thread local storage; set before calling MutexLocker
1651 this->initialize_thread_local_storage();
1652
1653 this->create_stack_guard_pages();
1654
1655 this->cache_global_variables();
1656
1657 // Thread is now sufficient initialized to be handled by the safepoint code as being
1658 // in the VM. Change thread state from _thread_new to _thread_in_vm
1659 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1660
1661 assert(JavaThread::current() == this, "sanity check");
1662 assert(!Thread::current()->owns_locks(), "sanity check");
1663
1664 DTRACE_THREAD_PROBE(start, this);
1665
1666 // This operation might block. We call that after all safepoint checks for a new thread has
1667 // been completed.
1668 this->set_active_handles(JNIHandleBlock::allocate_block());
1669
1670 if (JvmtiExport::should_post_thread_life()) {
1671 JvmtiExport::post_thread_start(this);
1672 }
1673
1674 EventThreadStart event;
1675 if (event.should_commit()) {
1676 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1677 event.commit();
1678 }
1679
1680 // We call another function to do the rest so we are sure that the stack addresses used
1681 // from there will be lower than the stack base just computed
1682 thread_main_inner();
1683
1684 // Note, thread is no longer valid at this point!
1685 }
1686
1687
1688 void JavaThread::thread_main_inner() {
1689 assert(JavaThread::current() == this, "sanity check");
1690 assert(this->threadObj() != NULL, "just checking");
1691
1692 // Execute thread entry point unless this thread has a pending exception
1693 // or has been stopped before starting.
1694 // Note: Due to JVM_StopThread we can have pending exceptions already!
1695 if (!this->has_pending_exception() &&
1696 !java_lang_Thread::is_stillborn(this->threadObj())) {
1697 {
1698 ResourceMark rm(this);
1699 this->set_native_thread_name(this->get_thread_name());
1700 }
1701 HandleMark hm(this);
1702 this->entry_point()(this, this);
1703 }
1704
1705 DTRACE_THREAD_PROBE(stop, this);
1706
1707 this->exit(false);
1708 delete this;
1709 }
1710
1711
1712 static void ensure_join(JavaThread* thread) {
1713 // We do not need to grap the Threads_lock, since we are operating on ourself.
1714 Handle threadObj(thread, thread->threadObj());
1715 assert(threadObj.not_null(), "java thread object must exist");
1716 ObjectLocker lock(threadObj, thread);
1717 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1718 thread->clear_pending_exception();
1719 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1720 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1721 // Clear the native thread instance - this makes isAlive return false and allows the join()
1722 // to complete once we've done the notify_all below
1723 java_lang_Thread::set_thread(threadObj(), NULL);
1724 lock.notify_all(thread);
1725 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1726 thread->clear_pending_exception();
1727 }
1728
1729
1730 // For any new cleanup additions, please check to see if they need to be applied to
1731 // cleanup_failed_attach_current_thread as well.
1732 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1733 assert(this == JavaThread::current(), "thread consistency check");
1734
1735 HandleMark hm(this);
1736 Handle uncaught_exception(this, this->pending_exception());
1737 this->clear_pending_exception();
1738 Handle threadObj(this, this->threadObj());
1739 assert(threadObj.not_null(), "Java thread object should be created");
1740
1741 if (get_thread_profiler() != NULL) {
1742 get_thread_profiler()->disengage();
1743 ResourceMark rm;
1744 get_thread_profiler()->print(get_thread_name());
1745 }
1746
1747
1748 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1749 {
1750 EXCEPTION_MARK;
1751
1752 CLEAR_PENDING_EXCEPTION;
1753 }
1754 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1755 // has to be fixed by a runtime query method
1756 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1757 // JSR-166: change call from from ThreadGroup.uncaughtException to
1758 // java.lang.Thread.dispatchUncaughtException
1759 if (uncaught_exception.not_null()) {
1760 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1761 {
1762 EXCEPTION_MARK;
1763 // Check if the method Thread.dispatchUncaughtException() exists. If so
1764 // call it. Otherwise we have an older library without the JSR-166 changes,
1765 // so call ThreadGroup.uncaughtException()
1766 KlassHandle recvrKlass(THREAD, threadObj->klass());
1767 CallInfo callinfo;
1768 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1769 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1770 vmSymbols::dispatchUncaughtException_name(),
1771 vmSymbols::throwable_void_signature(),
1772 KlassHandle(), false, false, THREAD);
1773 CLEAR_PENDING_EXCEPTION;
1774 methodHandle method = callinfo.selected_method();
1775 if (method.not_null()) {
1776 JavaValue result(T_VOID);
1777 JavaCalls::call_virtual(&result,
1778 threadObj, thread_klass,
1779 vmSymbols::dispatchUncaughtException_name(),
1780 vmSymbols::throwable_void_signature(),
1781 uncaught_exception,
1782 THREAD);
1783 } else {
1784 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1785 JavaValue result(T_VOID);
1786 JavaCalls::call_virtual(&result,
1787 group, thread_group,
1788 vmSymbols::uncaughtException_name(),
1789 vmSymbols::thread_throwable_void_signature(),
1790 threadObj, // Arg 1
1791 uncaught_exception, // Arg 2
1792 THREAD);
1793 }
1794 if (HAS_PENDING_EXCEPTION) {
1795 ResourceMark rm(this);
1796 jio_fprintf(defaultStream::error_stream(),
1797 "\nException: %s thrown from the UncaughtExceptionHandler"
1798 " in thread \"%s\"\n",
1799 pending_exception()->klass()->external_name(),
1800 get_thread_name());
1801 CLEAR_PENDING_EXCEPTION;
1802 }
1803 }
1804 }
1805
1806 // Called before the java thread exit since we want to read info
1807 // from java_lang_Thread object
1808 EventThreadEnd event;
1809 if (event.should_commit()) {
1810 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1811 event.commit();
1812 }
1813
1814 // Call after last event on thread
1815 EVENT_THREAD_EXIT(this);
1816
1817 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1818 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1819 // is deprecated anyhow.
1820 if (!is_Compiler_thread()) {
1821 int count = 3;
1822 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1823 EXCEPTION_MARK;
1824 JavaValue result(T_VOID);
1825 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1826 JavaCalls::call_virtual(&result,
1827 threadObj, thread_klass,
1828 vmSymbols::exit_method_name(),
1829 vmSymbols::void_method_signature(),
1830 THREAD);
1831 CLEAR_PENDING_EXCEPTION;
1832 }
1833 }
1834 // notify JVMTI
1835 if (JvmtiExport::should_post_thread_life()) {
1836 JvmtiExport::post_thread_end(this);
1837 }
1838
1839 // We have notified the agents that we are exiting, before we go on,
1840 // we must check for a pending external suspend request and honor it
1841 // in order to not surprise the thread that made the suspend request.
1842 while (true) {
1843 {
1844 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1845 if (!is_external_suspend()) {
1846 set_terminated(_thread_exiting);
1847 ThreadService::current_thread_exiting(this);
1848 break;
1849 }
1850 // Implied else:
1851 // Things get a little tricky here. We have a pending external
1852 // suspend request, but we are holding the SR_lock so we
1853 // can't just self-suspend. So we temporarily drop the lock
1854 // and then self-suspend.
1855 }
1856
1857 ThreadBlockInVM tbivm(this);
1858 java_suspend_self();
1859
1860 // We're done with this suspend request, but we have to loop around
1861 // and check again. Eventually we will get SR_lock without a pending
1862 // external suspend request and will be able to mark ourselves as
1863 // exiting.
1864 }
1865 // no more external suspends are allowed at this point
1866 } else {
1867 // before_exit() has already posted JVMTI THREAD_END events
1868 }
1869
1870 // Notify waiters on thread object. This has to be done after exit() is called
1871 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1872 // group should have the destroyed bit set before waiters are notified).
1873 ensure_join(this);
1874 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1875
1876 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1877 // held by this thread must be released. A detach operation must only
1878 // get here if there are no Java frames on the stack. Therefore, any
1879 // owned monitors at this point MUST be JNI-acquired monitors which are
1880 // pre-inflated and in the monitor cache.
1881 //
1882 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1883 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1884 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1885 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1886 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1887 }
1888
1889 // These things needs to be done while we are still a Java Thread. Make sure that thread
1890 // is in a consistent state, in case GC happens
1891 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1892
1893 if (active_handles() != NULL) {
1894 JNIHandleBlock* block = active_handles();
1895 set_active_handles(NULL);
1896 JNIHandleBlock::release_block(block);
1897 }
1898
1899 if (free_handle_block() != NULL) {
1900 JNIHandleBlock* block = free_handle_block();
1901 set_free_handle_block(NULL);
1902 JNIHandleBlock::release_block(block);
1903 }
1904
1905 // These have to be removed while this is still a valid thread.
1906 remove_stack_guard_pages();
1907
1908 if (UseTLAB) {
1909 tlab().make_parsable(true); // retire TLAB
1910 }
1911
1912 if (JvmtiEnv::environments_might_exist()) {
1913 JvmtiExport::cleanup_thread(this);
1914 }
1915
1916 // We must flush any deferred card marks before removing a thread from
1917 // the list of active threads.
1918 Universe::heap()->flush_deferred_store_barrier(this);
1919 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1920
1921 #if INCLUDE_ALL_GCS
1922 // We must flush the G1-related buffers before removing a thread
1923 // from the list of active threads. We must do this after any deferred
1924 // card marks have been flushed (above) so that any entries that are
1925 // added to the thread's dirty card queue as a result are not lost.
1926 if (UseG1GC) {
1927 flush_barrier_queues();
1928 }
1929 #endif // INCLUDE_ALL_GCS
1930
1931 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1932 Threads::remove(this);
1933 }
1934
1935 #if INCLUDE_ALL_GCS
1936 // Flush G1-related queues.
1937 void JavaThread::flush_barrier_queues() {
1938 satb_mark_queue().flush();
1939 dirty_card_queue().flush();
1940 }
1941
1942 void JavaThread::initialize_queues() {
1943 assert(!SafepointSynchronize::is_at_safepoint(),
1944 "we should not be at a safepoint");
1945
1946 ObjPtrQueue& satb_queue = satb_mark_queue();
1947 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1948 // The SATB queue should have been constructed with its active
1949 // field set to false.
1950 assert(!satb_queue.is_active(), "SATB queue should not be active");
1951 assert(satb_queue.is_empty(), "SATB queue should be empty");
1952 // If we are creating the thread during a marking cycle, we should
1953 // set the active field of the SATB queue to true.
1954 if (satb_queue_set.is_active()) {
1955 satb_queue.set_active(true);
1956 }
1957
1958 DirtyCardQueue& dirty_queue = dirty_card_queue();
1959 // The dirty card queue should have been constructed with its
1960 // active field set to true.
1961 assert(dirty_queue.is_active(), "dirty card queue should be active");
1962 }
1963 #endif // INCLUDE_ALL_GCS
1964
1965 void JavaThread::cleanup_failed_attach_current_thread() {
1966 if (get_thread_profiler() != NULL) {
1967 get_thread_profiler()->disengage();
1968 ResourceMark rm;
1969 get_thread_profiler()->print(get_thread_name());
1970 }
1971
1972 if (active_handles() != NULL) {
1973 JNIHandleBlock* block = active_handles();
1974 set_active_handles(NULL);
1975 JNIHandleBlock::release_block(block);
1976 }
1977
1978 if (free_handle_block() != NULL) {
1979 JNIHandleBlock* block = free_handle_block();
1980 set_free_handle_block(NULL);
1981 JNIHandleBlock::release_block(block);
1982 }
1983
1984 // These have to be removed while this is still a valid thread.
1985 remove_stack_guard_pages();
1986
1987 if (UseTLAB) {
1988 tlab().make_parsable(true); // retire TLAB, if any
1989 }
1990
1991 #if INCLUDE_ALL_GCS
1992 if (UseG1GC) {
1993 flush_barrier_queues();
1994 }
1995 #endif // INCLUDE_ALL_GCS
1996
1997 Threads::remove(this);
1998 delete this;
1999 }
2000
2001
2002
2003
2004 JavaThread* JavaThread::active() {
2005 Thread* thread = ThreadLocalStorage::thread();
2006 assert(thread != NULL, "just checking");
2007 if (thread->is_Java_thread()) {
2008 return (JavaThread*) thread;
2009 } else {
2010 assert(thread->is_VM_thread(), "this must be a vm thread");
2011 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2012 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2013 assert(ret->is_Java_thread(), "must be a Java thread");
2014 return ret;
2015 }
2016 }
2017
2018 bool JavaThread::is_lock_owned(address adr) const {
2019 if (Thread::is_lock_owned(adr)) return true;
2020
2021 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2022 if (chunk->contains(adr)) return true;
2023 }
2024
2025 return false;
2026 }
2027
2028
2029 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2030 chunk->set_next(monitor_chunks());
2031 set_monitor_chunks(chunk);
2032 }
2033
2034 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2035 guarantee(monitor_chunks() != NULL, "must be non empty");
2036 if (monitor_chunks() == chunk) {
2037 set_monitor_chunks(chunk->next());
2038 } else {
2039 MonitorChunk* prev = monitor_chunks();
2040 while (prev->next() != chunk) prev = prev->next();
2041 prev->set_next(chunk->next());
2042 }
2043 }
2044
2045 // JVM support.
2046
2047 // Note: this function shouldn't block if it's called in
2048 // _thread_in_native_trans state (such as from
2049 // check_special_condition_for_native_trans()).
2050 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2051
2052 if (has_last_Java_frame() && has_async_condition()) {
2053 // If we are at a polling page safepoint (not a poll return)
2054 // then we must defer async exception because live registers
2055 // will be clobbered by the exception path. Poll return is
2056 // ok because the call we a returning from already collides
2057 // with exception handling registers and so there is no issue.
2058 // (The exception handling path kills call result registers but
2059 // this is ok since the exception kills the result anyway).
2060
2061 if (is_at_poll_safepoint()) {
2062 // if the code we are returning to has deoptimized we must defer
2063 // the exception otherwise live registers get clobbered on the
2064 // exception path before deoptimization is able to retrieve them.
2065 //
2066 RegisterMap map(this, false);
2067 frame caller_fr = last_frame().sender(&map);
2068 assert(caller_fr.is_compiled_frame(), "what?");
2069 if (caller_fr.is_deoptimized_frame()) {
2070 if (TraceExceptions) {
2071 ResourceMark rm;
2072 tty->print_cr("deferred async exception at compiled safepoint");
2073 }
2074 return;
2075 }
2076 }
2077 }
2078
2079 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2080 if (condition == _no_async_condition) {
2081 // Conditions have changed since has_special_runtime_exit_condition()
2082 // was called:
2083 // - if we were here only because of an external suspend request,
2084 // then that was taken care of above (or cancelled) so we are done
2085 // - if we were here because of another async request, then it has
2086 // been cleared between the has_special_runtime_exit_condition()
2087 // and now so again we are done
2088 return;
2089 }
2090
2091 // Check for pending async. exception
2092 if (_pending_async_exception != NULL) {
2093 // Only overwrite an already pending exception, if it is not a threadDeath.
2094 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2095
2096 // We cannot call Exceptions::_throw(...) here because we cannot block
2097 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2098
2099 if (TraceExceptions) {
2100 ResourceMark rm;
2101 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2102 if (has_last_Java_frame() ) {
2103 frame f = last_frame();
2104 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2105 }
2106 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2107 }
2108 _pending_async_exception = NULL;
2109 clear_has_async_exception();
2110 }
2111 }
2112
2113 if (check_unsafe_error &&
2114 condition == _async_unsafe_access_error && !has_pending_exception()) {
2115 condition = _no_async_condition; // done
2116 switch (thread_state()) {
2117 case _thread_in_vm:
2118 {
2119 JavaThread* THREAD = this;
2120 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2121 }
2122 case _thread_in_native:
2123 {
2124 ThreadInVMfromNative tiv(this);
2125 JavaThread* THREAD = this;
2126 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2127 }
2128 case _thread_in_Java:
2129 {
2130 ThreadInVMfromJava tiv(this);
2131 JavaThread* THREAD = this;
2132 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2133 }
2134 default:
2135 ShouldNotReachHere();
2136 }
2137 }
2138
2139 assert(condition == _no_async_condition || has_pending_exception() ||
2140 (!check_unsafe_error && condition == _async_unsafe_access_error),
2141 "must have handled the async condition, if no exception");
2142 }
2143
2144 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2145 //
2146 // Check for pending external suspend. Internal suspend requests do
2147 // not use handle_special_runtime_exit_condition().
2148 // If JNIEnv proxies are allowed, don't self-suspend if the target
2149 // thread is not the current thread. In older versions of jdbx, jdbx
2150 // threads could call into the VM with another thread's JNIEnv so we
2151 // can be here operating on behalf of a suspended thread (4432884).
2152 bool do_self_suspend = is_external_suspend_with_lock();
2153 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2154 //
2155 // Because thread is external suspended the safepoint code will count
2156 // thread as at a safepoint. This can be odd because we can be here
2157 // as _thread_in_Java which would normally transition to _thread_blocked
2158 // at a safepoint. We would like to mark the thread as _thread_blocked
2159 // before calling java_suspend_self like all other callers of it but
2160 // we must then observe proper safepoint protocol. (We can't leave
2161 // _thread_blocked with a safepoint in progress). However we can be
2162 // here as _thread_in_native_trans so we can't use a normal transition
2163 // constructor/destructor pair because they assert on that type of
2164 // transition. We could do something like:
2165 //
2166 // JavaThreadState state = thread_state();
2167 // set_thread_state(_thread_in_vm);
2168 // {
2169 // ThreadBlockInVM tbivm(this);
2170 // java_suspend_self()
2171 // }
2172 // set_thread_state(_thread_in_vm_trans);
2173 // if (safepoint) block;
2174 // set_thread_state(state);
2175 //
2176 // but that is pretty messy. Instead we just go with the way the
2177 // code has worked before and note that this is the only path to
2178 // java_suspend_self that doesn't put the thread in _thread_blocked
2179 // mode.
2180
2181 frame_anchor()->make_walkable(this);
2182 java_suspend_self();
2183
2184 // We might be here for reasons in addition to the self-suspend request
2185 // so check for other async requests.
2186 }
2187
2188 if (check_asyncs) {
2189 check_and_handle_async_exceptions();
2190 }
2191 }
2192
2193 void JavaThread::send_thread_stop(oop java_throwable) {
2194 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2195 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2196 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2197
2198 // Do not throw asynchronous exceptions against the compiler thread
2199 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2200 if (is_Compiler_thread()) return;
2201
2202 {
2203 // Actually throw the Throwable against the target Thread - however
2204 // only if there is no thread death exception installed already.
2205 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2206 // If the topmost frame is a runtime stub, then we are calling into
2207 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2208 // must deoptimize the caller before continuing, as the compiled exception handler table
2209 // may not be valid
2210 if (has_last_Java_frame()) {
2211 frame f = last_frame();
2212 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2213 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2214 RegisterMap reg_map(this, UseBiasedLocking);
2215 frame compiled_frame = f.sender(®_map);
2216 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2217 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2218 }
2219 }
2220 }
2221
2222 // Set async. pending exception in thread.
2223 set_pending_async_exception(java_throwable);
2224
2225 if (TraceExceptions) {
2226 ResourceMark rm;
2227 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2228 }
2229 // for AbortVMOnException flag
2230 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2231 }
2232 }
2233
2234
2235 // Interrupt thread so it will wake up from a potential wait()
2236 Thread::interrupt(this);
2237 }
2238
2239 // External suspension mechanism.
2240 //
2241 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2242 // to any VM_locks and it is at a transition
2243 // Self-suspension will happen on the transition out of the vm.
2244 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2245 //
2246 // Guarantees on return:
2247 // + Target thread will not execute any new bytecode (that's why we need to
2248 // force a safepoint)
2249 // + Target thread will not enter any new monitors
2250 //
2251 void JavaThread::java_suspend() {
2252 { MutexLocker mu(Threads_lock);
2253 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2254 return;
2255 }
2256 }
2257
2258 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2259 if (!is_external_suspend()) {
2260 // a racing resume has cancelled us; bail out now
2261 return;
2262 }
2263
2264 // suspend is done
2265 uint32_t debug_bits = 0;
2266 // Warning: is_ext_suspend_completed() may temporarily drop the
2267 // SR_lock to allow the thread to reach a stable thread state if
2268 // it is currently in a transient thread state.
2269 if (is_ext_suspend_completed(false /* !called_by_wait */,
2270 SuspendRetryDelay, &debug_bits) ) {
2271 return;
2272 }
2273 }
2274
2275 VM_ForceSafepoint vm_suspend;
2276 VMThread::execute(&vm_suspend);
2277 }
2278
2279 // Part II of external suspension.
2280 // A JavaThread self suspends when it detects a pending external suspend
2281 // request. This is usually on transitions. It is also done in places
2282 // where continuing to the next transition would surprise the caller,
2283 // e.g., monitor entry.
2284 //
2285 // Returns the number of times that the thread self-suspended.
2286 //
2287 // Note: DO NOT call java_suspend_self() when you just want to block current
2288 // thread. java_suspend_self() is the second stage of cooperative
2289 // suspension for external suspend requests and should only be used
2290 // to complete an external suspend request.
2291 //
2292 int JavaThread::java_suspend_self() {
2293 int ret = 0;
2294
2295 // we are in the process of exiting so don't suspend
2296 if (is_exiting()) {
2297 clear_external_suspend();
2298 return ret;
2299 }
2300
2301 assert(_anchor.walkable() ||
2302 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2303 "must have walkable stack");
2304
2305 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2306
2307 assert(!this->is_ext_suspended(),
2308 "a thread trying to self-suspend should not already be suspended");
2309
2310 if (this->is_suspend_equivalent()) {
2311 // If we are self-suspending as a result of the lifting of a
2312 // suspend equivalent condition, then the suspend_equivalent
2313 // flag is not cleared until we set the ext_suspended flag so
2314 // that wait_for_ext_suspend_completion() returns consistent
2315 // results.
2316 this->clear_suspend_equivalent();
2317 }
2318
2319 // A racing resume may have cancelled us before we grabbed SR_lock
2320 // above. Or another external suspend request could be waiting for us
2321 // by the time we return from SR_lock()->wait(). The thread
2322 // that requested the suspension may already be trying to walk our
2323 // stack and if we return now, we can change the stack out from under
2324 // it. This would be a "bad thing (TM)" and cause the stack walker
2325 // to crash. We stay self-suspended until there are no more pending
2326 // external suspend requests.
2327 while (is_external_suspend()) {
2328 ret++;
2329 this->set_ext_suspended();
2330
2331 // _ext_suspended flag is cleared by java_resume()
2332 while (is_ext_suspended()) {
2333 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2334 }
2335 }
2336
2337 return ret;
2338 }
2339
2340 #ifdef ASSERT
2341 // verify the JavaThread has not yet been published in the Threads::list, and
2342 // hence doesn't need protection from concurrent access at this stage
2343 void JavaThread::verify_not_published() {
2344 if (!Threads_lock->owned_by_self()) {
2345 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2346 assert( !Threads::includes(this),
2347 "java thread shouldn't have been published yet!");
2348 }
2349 else {
2350 assert( !Threads::includes(this),
2351 "java thread shouldn't have been published yet!");
2352 }
2353 }
2354 #endif
2355
2356 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2357 // progress or when _suspend_flags is non-zero.
2358 // Current thread needs to self-suspend if there is a suspend request and/or
2359 // block if a safepoint is in progress.
2360 // Async exception ISN'T checked.
2361 // Note only the ThreadInVMfromNative transition can call this function
2362 // directly and when thread state is _thread_in_native_trans
2363 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2364 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2365
2366 JavaThread *curJT = JavaThread::current();
2367 bool do_self_suspend = thread->is_external_suspend();
2368
2369 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2370
2371 // If JNIEnv proxies are allowed, don't self-suspend if the target
2372 // thread is not the current thread. In older versions of jdbx, jdbx
2373 // threads could call into the VM with another thread's JNIEnv so we
2374 // can be here operating on behalf of a suspended thread (4432884).
2375 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2376 JavaThreadState state = thread->thread_state();
2377
2378 // We mark this thread_blocked state as a suspend-equivalent so
2379 // that a caller to is_ext_suspend_completed() won't be confused.
2380 // The suspend-equivalent state is cleared by java_suspend_self().
2381 thread->set_suspend_equivalent();
2382
2383 // If the safepoint code sees the _thread_in_native_trans state, it will
2384 // wait until the thread changes to other thread state. There is no
2385 // guarantee on how soon we can obtain the SR_lock and complete the
2386 // self-suspend request. It would be a bad idea to let safepoint wait for
2387 // too long. Temporarily change the state to _thread_blocked to
2388 // let the VM thread know that this thread is ready for GC. The problem
2389 // of changing thread state is that safepoint could happen just after
2390 // java_suspend_self() returns after being resumed, and VM thread will
2391 // see the _thread_blocked state. We must check for safepoint
2392 // after restoring the state and make sure we won't leave while a safepoint
2393 // is in progress.
2394 thread->set_thread_state(_thread_blocked);
2395 thread->java_suspend_self();
2396 thread->set_thread_state(state);
2397 // Make sure new state is seen by VM thread
2398 if (os::is_MP()) {
2399 if (UseMembar) {
2400 // Force a fence between the write above and read below
2401 OrderAccess::fence();
2402 } else {
2403 // Must use this rather than serialization page in particular on Windows
2404 InterfaceSupport::serialize_memory(thread);
2405 }
2406 }
2407 }
2408
2409 if (SafepointSynchronize::do_call_back()) {
2410 // If we are safepointing, then block the caller which may not be
2411 // the same as the target thread (see above).
2412 SafepointSynchronize::block(curJT);
2413 }
2414
2415 if (thread->is_deopt_suspend()) {
2416 thread->clear_deopt_suspend();
2417 RegisterMap map(thread, false);
2418 frame f = thread->last_frame();
2419 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2420 f = f.sender(&map);
2421 }
2422 if (f.id() == thread->must_deopt_id()) {
2423 thread->clear_must_deopt_id();
2424 f.deoptimize(thread);
2425 } else {
2426 fatal("missed deoptimization!");
2427 }
2428 }
2429 }
2430
2431 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2432 // progress or when _suspend_flags is non-zero.
2433 // Current thread needs to self-suspend if there is a suspend request and/or
2434 // block if a safepoint is in progress.
2435 // Also check for pending async exception (not including unsafe access error).
2436 // Note only the native==>VM/Java barriers can call this function and when
2437 // thread state is _thread_in_native_trans.
2438 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2439 check_safepoint_and_suspend_for_native_trans(thread);
2440
2441 if (thread->has_async_exception()) {
2442 // We are in _thread_in_native_trans state, don't handle unsafe
2443 // access error since that may block.
2444 thread->check_and_handle_async_exceptions(false);
2445 }
2446 }
2447
2448 // This is a variant of the normal
2449 // check_special_condition_for_native_trans with slightly different
2450 // semantics for use by critical native wrappers. It does all the
2451 // normal checks but also performs the transition back into
2452 // thread_in_Java state. This is required so that critical natives
2453 // can potentially block and perform a GC if they are the last thread
2454 // exiting the GC_locker.
2455 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2456 check_special_condition_for_native_trans(thread);
2457
2458 // Finish the transition
2459 thread->set_thread_state(_thread_in_Java);
2460
2461 if (thread->do_critical_native_unlock()) {
2462 ThreadInVMfromJavaNoAsyncException tiv(thread);
2463 GC_locker::unlock_critical(thread);
2464 thread->clear_critical_native_unlock();
2465 }
2466 }
2467
2468 // We need to guarantee the Threads_lock here, since resumes are not
2469 // allowed during safepoint synchronization
2470 // Can only resume from an external suspension
2471 void JavaThread::java_resume() {
2472 assert_locked_or_safepoint(Threads_lock);
2473
2474 // Sanity check: thread is gone, has started exiting or the thread
2475 // was not externally suspended.
2476 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2477 return;
2478 }
2479
2480 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2481
2482 clear_external_suspend();
2483
2484 if (is_ext_suspended()) {
2485 clear_ext_suspended();
2486 SR_lock()->notify_all();
2487 }
2488 }
2489
2490 void JavaThread::create_stack_guard_pages() {
2491 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2492 address low_addr = stack_base() - stack_size();
2493 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2494
2495 int allocate = os::allocate_stack_guard_pages();
2496 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2497
2498 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2499 warning("Attempt to allocate stack guard pages failed.");
2500 return;
2501 }
2502
2503 if (os::guard_memory((char *) low_addr, len)) {
2504 _stack_guard_state = stack_guard_enabled;
2505 } else {
2506 warning("Attempt to protect stack guard pages failed.");
2507 if (os::uncommit_memory((char *) low_addr, len)) {
2508 warning("Attempt to deallocate stack guard pages failed.");
2509 }
2510 }
2511 }
2512
2513 void JavaThread::remove_stack_guard_pages() {
2514 assert(Thread::current() == this, "from different thread");
2515 if (_stack_guard_state == stack_guard_unused) return;
2516 address low_addr = stack_base() - stack_size();
2517 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2518
2519 if (os::allocate_stack_guard_pages()) {
2520 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2521 _stack_guard_state = stack_guard_unused;
2522 } else {
2523 warning("Attempt to deallocate stack guard pages failed.");
2524 }
2525 } else {
2526 if (_stack_guard_state == stack_guard_unused) return;
2527 if (os::unguard_memory((char *) low_addr, len)) {
2528 _stack_guard_state = stack_guard_unused;
2529 } else {
2530 warning("Attempt to unprotect stack guard pages failed.");
2531 }
2532 }
2533 }
2534
2535 void JavaThread::enable_stack_yellow_zone() {
2536 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2537 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2538
2539 // The base notation is from the stacks point of view, growing downward.
2540 // We need to adjust it to work correctly with guard_memory()
2541 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2542
2543 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2544 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2545
2546 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2547 _stack_guard_state = stack_guard_enabled;
2548 } else {
2549 warning("Attempt to guard stack yellow zone failed.");
2550 }
2551 enable_register_stack_guard();
2552 }
2553
2554 void JavaThread::disable_stack_yellow_zone() {
2555 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2556 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2557
2558 // Simply return if called for a thread that does not use guard pages.
2559 if (_stack_guard_state == stack_guard_unused) return;
2560
2561 // The base notation is from the stacks point of view, growing downward.
2562 // We need to adjust it to work correctly with guard_memory()
2563 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2564
2565 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2566 _stack_guard_state = stack_guard_yellow_disabled;
2567 } else {
2568 warning("Attempt to unguard stack yellow zone failed.");
2569 }
2570 disable_register_stack_guard();
2571 }
2572
2573 void JavaThread::enable_stack_red_zone() {
2574 // The base notation is from the stacks point of view, growing downward.
2575 // We need to adjust it to work correctly with guard_memory()
2576 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2577 address base = stack_red_zone_base() - stack_red_zone_size();
2578
2579 guarantee(base < stack_base(),"Error calculating stack red zone");
2580 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2581
2582 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2583 warning("Attempt to guard stack red zone failed.");
2584 }
2585 }
2586
2587 void JavaThread::disable_stack_red_zone() {
2588 // The base notation is from the stacks point of view, growing downward.
2589 // We need to adjust it to work correctly with guard_memory()
2590 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2591 address base = stack_red_zone_base() - stack_red_zone_size();
2592 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2593 warning("Attempt to unguard stack red zone failed.");
2594 }
2595 }
2596
2597 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2598 // ignore is there is no stack
2599 if (!has_last_Java_frame()) return;
2600 // traverse the stack frames. Starts from top frame.
2601 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2602 frame* fr = fst.current();
2603 f(fr, fst.register_map());
2604 }
2605 }
2606
2607
2608 #ifndef PRODUCT
2609 // Deoptimization
2610 // Function for testing deoptimization
2611 void JavaThread::deoptimize() {
2612 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2613 StackFrameStream fst(this, UseBiasedLocking);
2614 bool deopt = false; // Dump stack only if a deopt actually happens.
2615 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2616 // Iterate over all frames in the thread and deoptimize
2617 for(; !fst.is_done(); fst.next()) {
2618 if(fst.current()->can_be_deoptimized()) {
2619
2620 if (only_at) {
2621 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2622 // consists of comma or carriage return separated numbers so
2623 // search for the current bci in that string.
2624 address pc = fst.current()->pc();
2625 nmethod* nm = (nmethod*) fst.current()->cb();
2626 ScopeDesc* sd = nm->scope_desc_at( pc);
2627 char buffer[8];
2628 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2629 size_t len = strlen(buffer);
2630 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2631 while (found != NULL) {
2632 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2633 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2634 // Check that the bci found is bracketed by terminators.
2635 break;
2636 }
2637 found = strstr(found + 1, buffer);
2638 }
2639 if (!found) {
2640 continue;
2641 }
2642 }
2643
2644 if (DebugDeoptimization && !deopt) {
2645 deopt = true; // One-time only print before deopt
2646 tty->print_cr("[BEFORE Deoptimization]");
2647 trace_frames();
2648 trace_stack();
2649 }
2650 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2651 }
2652 }
2653
2654 if (DebugDeoptimization && deopt) {
2655 tty->print_cr("[AFTER Deoptimization]");
2656 trace_frames();
2657 }
2658 }
2659
2660
2661 // Make zombies
2662 void JavaThread::make_zombies() {
2663 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2664 if (fst.current()->can_be_deoptimized()) {
2665 // it is a Java nmethod
2666 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2667 nm->make_not_entrant();
2668 }
2669 }
2670 }
2671 #endif // PRODUCT
2672
2673
2674 void JavaThread::deoptimized_wrt_marked_nmethods() {
2675 if (!has_last_Java_frame()) return;
2676 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2677 StackFrameStream fst(this, UseBiasedLocking);
2678 for(; !fst.is_done(); fst.next()) {
2679 if (fst.current()->should_be_deoptimized()) {
2680 if (LogCompilation && xtty != NULL) {
2681 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2682 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2683 this->name(), nm != NULL ? nm->compile_id() : -1);
2684 }
2685
2686 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2687 }
2688 }
2689 }
2690
2691
2692 // GC support
2693 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2694
2695 void JavaThread::gc_epilogue() {
2696 frames_do(frame_gc_epilogue);
2697 }
2698
2699
2700 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2701
2702 void JavaThread::gc_prologue() {
2703 frames_do(frame_gc_prologue);
2704 }
2705
2706 // If the caller is a NamedThread, then remember, in the current scope,
2707 // the given JavaThread in its _processed_thread field.
2708 class RememberProcessedThread: public StackObj {
2709 NamedThread* _cur_thr;
2710 public:
2711 RememberProcessedThread(JavaThread* jthr) {
2712 Thread* thread = Thread::current();
2713 if (thread->is_Named_thread()) {
2714 _cur_thr = (NamedThread *)thread;
2715 _cur_thr->set_processed_thread(jthr);
2716 } else {
2717 _cur_thr = NULL;
2718 }
2719 }
2720
2721 ~RememberProcessedThread() {
2722 if (_cur_thr) {
2723 _cur_thr->set_processed_thread(NULL);
2724 }
2725 }
2726 };
2727
2728 void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
2729 // Verify that the deferred card marks have been flushed.
2730 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2731
2732 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2733 // since there may be more than one thread using each ThreadProfiler.
2734
2735 // Traverse the GCHandles
2736 Thread::oops_do(f, cld_f, cf);
2737
2738 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2739 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2740
2741 if (has_last_Java_frame()) {
2742 // Record JavaThread to GC thread
2743 RememberProcessedThread rpt(this);
2744
2745 // Traverse the privileged stack
2746 if (_privileged_stack_top != NULL) {
2747 _privileged_stack_top->oops_do(f);
2748 }
2749
2750 // traverse the registered growable array
2751 if (_array_for_gc != NULL) {
2752 for (int index = 0; index < _array_for_gc->length(); index++) {
2753 f->do_oop(_array_for_gc->adr_at(index));
2754 }
2755 }
2756
2757 // Traverse the monitor chunks
2758 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2759 chunk->oops_do(f);
2760 }
2761
2762 // Traverse the execution stack
2763 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2764 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2765 }
2766 }
2767
2768 // callee_target is never live across a gc point so NULL it here should
2769 // it still contain a methdOop.
2770
2771 set_callee_target(NULL);
2772
2773 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2774 // If we have deferred set_locals there might be oops waiting to be
2775 // written
2776 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2777 if (list != NULL) {
2778 for (int i = 0; i < list->length(); i++) {
2779 list->at(i)->oops_do(f);
2780 }
2781 }
2782
2783 // Traverse instance variables at the end since the GC may be moving things
2784 // around using this function
2785 f->do_oop((oop*) &_threadObj);
2786 f->do_oop((oop*) &_vm_result);
2787 f->do_oop((oop*) &_exception_oop);
2788 f->do_oop((oop*) &_pending_async_exception);
2789
2790 if (jvmti_thread_state() != NULL) {
2791 jvmti_thread_state()->oops_do(f);
2792 }
2793 }
2794
2795 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2796 Thread::nmethods_do(cf); // (super method is a no-op)
2797
2798 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2799 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2800
2801 if (has_last_Java_frame()) {
2802 // Traverse the execution stack
2803 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2804 fst.current()->nmethods_do(cf);
2805 }
2806 }
2807 }
2808
2809 void JavaThread::metadata_do(void f(Metadata*)) {
2810 Thread::metadata_do(f);
2811 if (has_last_Java_frame()) {
2812 // Traverse the execution stack to call f() on the methods in the stack
2813 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2814 fst.current()->metadata_do(f);
2815 }
2816 } else if (is_Compiler_thread()) {
2817 // need to walk ciMetadata in current compile tasks to keep alive.
2818 CompilerThread* ct = (CompilerThread*)this;
2819 if (ct->env() != NULL) {
2820 ct->env()->metadata_do(f);
2821 }
2822 }
2823 }
2824
2825 // Printing
2826 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2827 switch (_thread_state) {
2828 case _thread_uninitialized: return "_thread_uninitialized";
2829 case _thread_new: return "_thread_new";
2830 case _thread_new_trans: return "_thread_new_trans";
2831 case _thread_in_native: return "_thread_in_native";
2832 case _thread_in_native_trans: return "_thread_in_native_trans";
2833 case _thread_in_vm: return "_thread_in_vm";
2834 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2835 case _thread_in_Java: return "_thread_in_Java";
2836 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2837 case _thread_blocked: return "_thread_blocked";
2838 case _thread_blocked_trans: return "_thread_blocked_trans";
2839 default: return "unknown thread state";
2840 }
2841 }
2842
2843 #ifndef PRODUCT
2844 void JavaThread::print_thread_state_on(outputStream *st) const {
2845 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2846 };
2847 void JavaThread::print_thread_state() const {
2848 print_thread_state_on(tty);
2849 };
2850 #endif // PRODUCT
2851
2852 // Called by Threads::print() for VM_PrintThreads operation
2853 void JavaThread::print_on(outputStream *st) const {
2854 st->print("\"%s\" ", get_thread_name());
2855 oop thread_oop = threadObj();
2856 if (thread_oop != NULL) {
2857 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2858 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2859 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2860 }
2861 Thread::print_on(st);
2862 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2863 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2864 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2865 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2866 }
2867 #ifndef PRODUCT
2868 print_thread_state_on(st);
2869 _safepoint_state->print_on(st);
2870 #endif // PRODUCT
2871 }
2872
2873 // Called by fatal error handler. The difference between this and
2874 // JavaThread::print() is that we can't grab lock or allocate memory.
2875 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2876 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2877 oop thread_obj = threadObj();
2878 if (thread_obj != NULL) {
2879 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2880 }
2881 st->print(" [");
2882 st->print("%s", _get_thread_state_name(_thread_state));
2883 if (osthread()) {
2884 st->print(", id=%d", osthread()->thread_id());
2885 }
2886 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2887 _stack_base - _stack_size, _stack_base);
2888 st->print("]");
2889 return;
2890 }
2891
2892 // Verification
2893
2894 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2895
2896 void JavaThread::verify() {
2897 // Verify oops in the thread.
2898 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2899
2900 // Verify the stack frames.
2901 frames_do(frame_verify);
2902 }
2903
2904 // CR 6300358 (sub-CR 2137150)
2905 // Most callers of this method assume that it can't return NULL but a
2906 // thread may not have a name whilst it is in the process of attaching to
2907 // the VM - see CR 6412693, and there are places where a JavaThread can be
2908 // seen prior to having it's threadObj set (eg JNI attaching threads and
2909 // if vm exit occurs during initialization). These cases can all be accounted
2910 // for such that this method never returns NULL.
2911 const char* JavaThread::get_thread_name() const {
2912 #ifdef ASSERT
2913 // early safepoints can hit while current thread does not yet have TLS
2914 if (!SafepointSynchronize::is_at_safepoint()) {
2915 Thread *cur = Thread::current();
2916 if (!(cur->is_Java_thread() && cur == this)) {
2917 // Current JavaThreads are allowed to get their own name without
2918 // the Threads_lock.
2919 assert_locked_or_safepoint(Threads_lock);
2920 }
2921 }
2922 #endif // ASSERT
2923 return get_thread_name_string();
2924 }
2925
2926 // Returns a non-NULL representation of this thread's name, or a suitable
2927 // descriptive string if there is no set name
2928 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2929 const char* name_str;
2930 oop thread_obj = threadObj();
2931 if (thread_obj != NULL) {
2932 typeArrayOop name = java_lang_Thread::name(thread_obj);
2933 if (name != NULL) {
2934 if (buf == NULL) {
2935 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2936 }
2937 else {
2938 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2939 }
2940 }
2941 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2942 name_str = "<no-name - thread is attaching>";
2943 }
2944 else {
2945 name_str = Thread::name();
2946 }
2947 }
2948 else {
2949 name_str = Thread::name();
2950 }
2951 assert(name_str != NULL, "unexpected NULL thread name");
2952 return name_str;
2953 }
2954
2955
2956 const char* JavaThread::get_threadgroup_name() const {
2957 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2958 oop thread_obj = threadObj();
2959 if (thread_obj != NULL) {
2960 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2961 if (thread_group != NULL) {
2962 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2963 // ThreadGroup.name can be null
2964 if (name != NULL) {
2965 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2966 return str;
2967 }
2968 }
2969 }
2970 return NULL;
2971 }
2972
2973 const char* JavaThread::get_parent_name() const {
2974 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2975 oop thread_obj = threadObj();
2976 if (thread_obj != NULL) {
2977 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2978 if (thread_group != NULL) {
2979 oop parent = java_lang_ThreadGroup::parent(thread_group);
2980 if (parent != NULL) {
2981 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2982 // ThreadGroup.name can be null
2983 if (name != NULL) {
2984 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2985 return str;
2986 }
2987 }
2988 }
2989 }
2990 return NULL;
2991 }
2992
2993 ThreadPriority JavaThread::java_priority() const {
2994 oop thr_oop = threadObj();
2995 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2996 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2997 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2998 return priority;
2999 }
3000
3001 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3002
3003 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3004 // Link Java Thread object <-> C++ Thread
3005
3006 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3007 // and put it into a new Handle. The Handle "thread_oop" can then
3008 // be used to pass the C++ thread object to other methods.
3009
3010 // Set the Java level thread object (jthread) field of the
3011 // new thread (a JavaThread *) to C++ thread object using the
3012 // "thread_oop" handle.
3013
3014 // Set the thread field (a JavaThread *) of the
3015 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3016
3017 Handle thread_oop(Thread::current(),
3018 JNIHandles::resolve_non_null(jni_thread));
3019 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3020 "must be initialized");
3021 set_threadObj(thread_oop());
3022 java_lang_Thread::set_thread(thread_oop(), this);
3023
3024 if (prio == NoPriority) {
3025 prio = java_lang_Thread::priority(thread_oop());
3026 assert(prio != NoPriority, "A valid priority should be present");
3027 }
3028
3029 // Push the Java priority down to the native thread; needs Threads_lock
3030 Thread::set_priority(this, prio);
3031
3032 // Add the new thread to the Threads list and set it in motion.
3033 // We must have threads lock in order to call Threads::add.
3034 // It is crucial that we do not block before the thread is
3035 // added to the Threads list for if a GC happens, then the java_thread oop
3036 // will not be visited by GC.
3037 Threads::add(this);
3038 }
3039
3040 oop JavaThread::current_park_blocker() {
3041 // Support for JSR-166 locks
3042 oop thread_oop = threadObj();
3043 if (thread_oop != NULL &&
3044 JDK_Version::current().supports_thread_park_blocker()) {
3045 return java_lang_Thread::park_blocker(thread_oop);
3046 }
3047 return NULL;
3048 }
3049
3050
3051 void JavaThread::print_stack_on(outputStream* st) {
3052 if (!has_last_Java_frame()) return;
3053 ResourceMark rm;
3054 HandleMark hm;
3055
3056 RegisterMap reg_map(this);
3057 vframe* start_vf = last_java_vframe(®_map);
3058 int count = 0;
3059 for (vframe* f = start_vf; f; f = f->sender() ) {
3060 if (f->is_java_frame()) {
3061 javaVFrame* jvf = javaVFrame::cast(f);
3062 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3063
3064 // Print out lock information
3065 if (JavaMonitorsInStackTrace) {
3066 jvf->print_lock_info_on(st, count);
3067 }
3068 } else {
3069 // Ignore non-Java frames
3070 }
3071
3072 // Bail-out case for too deep stacks
3073 count++;
3074 if (MaxJavaStackTraceDepth == count) return;
3075 }
3076 }
3077
3078
3079 // JVMTI PopFrame support
3080 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3081 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3082 if (in_bytes(size_in_bytes) != 0) {
3083 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3084 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3085 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3086 }
3087 }
3088
3089 void* JavaThread::popframe_preserved_args() {
3090 return _popframe_preserved_args;
3091 }
3092
3093 ByteSize JavaThread::popframe_preserved_args_size() {
3094 return in_ByteSize(_popframe_preserved_args_size);
3095 }
3096
3097 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3098 int sz = in_bytes(popframe_preserved_args_size());
3099 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3100 return in_WordSize(sz / wordSize);
3101 }
3102
3103 void JavaThread::popframe_free_preserved_args() {
3104 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3105 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3106 _popframe_preserved_args = NULL;
3107 _popframe_preserved_args_size = 0;
3108 }
3109
3110 #ifndef PRODUCT
3111
3112 void JavaThread::trace_frames() {
3113 tty->print_cr("[Describe stack]");
3114 int frame_no = 1;
3115 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3116 tty->print(" %d. ", frame_no++);
3117 fst.current()->print_value_on(tty,this);
3118 tty->cr();
3119 }
3120 }
3121
3122 class PrintAndVerifyOopClosure: public OopClosure {
3123 protected:
3124 template <class T> inline void do_oop_work(T* p) {
3125 oop obj = oopDesc::load_decode_heap_oop(p);
3126 if (obj == NULL) return;
3127 tty->print(INTPTR_FORMAT ": ", p);
3128 if (obj->is_oop_or_null()) {
3129 if (obj->is_objArray()) {
3130 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3131 } else {
3132 obj->print();
3133 }
3134 } else {
3135 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3136 }
3137 tty->cr();
3138 }
3139 public:
3140 virtual void do_oop(oop* p) { do_oop_work(p); }
3141 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3142 };
3143
3144
3145 static void oops_print(frame* f, const RegisterMap *map) {
3146 PrintAndVerifyOopClosure print;
3147 f->print_value();
3148 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3149 }
3150
3151 // Print our all the locations that contain oops and whether they are
3152 // valid or not. This useful when trying to find the oldest frame
3153 // where an oop has gone bad since the frame walk is from youngest to
3154 // oldest.
3155 void JavaThread::trace_oops() {
3156 tty->print_cr("[Trace oops]");
3157 frames_do(oops_print);
3158 }
3159
3160
3161 #ifdef ASSERT
3162 // Print or validate the layout of stack frames
3163 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3164 ResourceMark rm;
3165 PRESERVE_EXCEPTION_MARK;
3166 FrameValues values;
3167 int frame_no = 0;
3168 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3169 fst.current()->describe(values, ++frame_no);
3170 if (depth == frame_no) break;
3171 }
3172 if (validate_only) {
3173 values.validate();
3174 } else {
3175 tty->print_cr("[Describe stack layout]");
3176 values.print(this);
3177 }
3178 }
3179 #endif
3180
3181 void JavaThread::trace_stack_from(vframe* start_vf) {
3182 ResourceMark rm;
3183 int vframe_no = 1;
3184 for (vframe* f = start_vf; f; f = f->sender() ) {
3185 if (f->is_java_frame()) {
3186 javaVFrame::cast(f)->print_activation(vframe_no++);
3187 } else {
3188 f->print();
3189 }
3190 if (vframe_no > StackPrintLimit) {
3191 tty->print_cr("...<more frames>...");
3192 return;
3193 }
3194 }
3195 }
3196
3197
3198 void JavaThread::trace_stack() {
3199 if (!has_last_Java_frame()) return;
3200 ResourceMark rm;
3201 HandleMark hm;
3202 RegisterMap reg_map(this);
3203 trace_stack_from(last_java_vframe(®_map));
3204 }
3205
3206
3207 #endif // PRODUCT
3208
3209
3210 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3211 assert(reg_map != NULL, "a map must be given");
3212 frame f = last_frame();
3213 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3214 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3215 }
3216 return NULL;
3217 }
3218
3219
3220 Klass* JavaThread::security_get_caller_class(int depth) {
3221 vframeStream vfst(this);
3222 vfst.security_get_caller_frame(depth);
3223 if (!vfst.at_end()) {
3224 return vfst.method()->method_holder();
3225 }
3226 return NULL;
3227 }
3228
3229 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3230 assert(thread->is_Compiler_thread(), "must be compiler thread");
3231 CompileBroker::compiler_thread_loop();
3232 }
3233
3234 // Create a CompilerThread
3235 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3236 : JavaThread(&compiler_thread_entry) {
3237 _env = NULL;
3238 _log = NULL;
3239 _task = NULL;
3240 _queue = queue;
3241 _counters = counters;
3242 _buffer_blob = NULL;
3243 _scanned_nmethod = NULL;
3244 _compiler = NULL;
3245
3246 #ifndef PRODUCT
3247 _ideal_graph_printer = NULL;
3248 #endif
3249 }
3250
3251 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
3252 JavaThread::oops_do(f, cld_f, cf);
3253 if (_scanned_nmethod != NULL && cf != NULL) {
3254 // Safepoints can occur when the sweeper is scanning an nmethod so
3255 // process it here to make sure it isn't unloaded in the middle of
3256 // a scan.
3257 cf->do_code_blob(_scanned_nmethod);
3258 }
3259 }
3260
3261
3262 // ======= Threads ========
3263
3264 // The Threads class links together all active threads, and provides
3265 // operations over all threads. It is protected by its own Mutex
3266 // lock, which is also used in other contexts to protect thread
3267 // operations from having the thread being operated on from exiting
3268 // and going away unexpectedly (e.g., safepoint synchronization)
3269
3270 JavaThread* Threads::_thread_list = NULL;
3271 int Threads::_number_of_threads = 0;
3272 int Threads::_number_of_non_daemon_threads = 0;
3273 int Threads::_return_code = 0;
3274 size_t JavaThread::_stack_size_at_create = 0;
3275 #ifdef ASSERT
3276 bool Threads::_vm_complete = false;
3277 #endif
3278
3279 // All JavaThreads
3280 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3281
3282 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3283 void Threads::threads_do(ThreadClosure* tc) {
3284 assert_locked_or_safepoint(Threads_lock);
3285 // ALL_JAVA_THREADS iterates through all JavaThreads
3286 ALL_JAVA_THREADS(p) {
3287 tc->do_thread(p);
3288 }
3289 // Someday we could have a table or list of all non-JavaThreads.
3290 // For now, just manually iterate through them.
3291 tc->do_thread(VMThread::vm_thread());
3292 Universe::heap()->gc_threads_do(tc);
3293 WatcherThread *wt = WatcherThread::watcher_thread();
3294 // Strictly speaking, the following NULL check isn't sufficient to make sure
3295 // the data for WatcherThread is still valid upon being examined. However,
3296 // considering that WatchThread terminates when the VM is on the way to
3297 // exit at safepoint, the chance of the above is extremely small. The right
3298 // way to prevent termination of WatcherThread would be to acquire
3299 // Terminator_lock, but we can't do that without violating the lock rank
3300 // checking in some cases.
3301 if (wt != NULL)
3302 tc->do_thread(wt);
3303
3304 // If CompilerThreads ever become non-JavaThreads, add them here
3305 }
3306
3307 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3308
3309 extern void JDK_Version_init();
3310
3311 // Check version
3312 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3313
3314 // Initialize the output stream module
3315 ostream_init();
3316
3317 // Process java launcher properties.
3318 Arguments::process_sun_java_launcher_properties(args);
3319
3320 // Initialize the os module before using TLS
3321 os::init();
3322
3323 // Initialize system properties.
3324 Arguments::init_system_properties();
3325
3326 // So that JDK version can be used as a discrimintor when parsing arguments
3327 JDK_Version_init();
3328
3329 // Update/Initialize System properties after JDK version number is known
3330 Arguments::init_version_specific_system_properties();
3331
3332 // Parse arguments
3333 jint parse_result = Arguments::parse(args);
3334 if (parse_result != JNI_OK) return parse_result;
3335
3336 os::init_before_ergo();
3337
3338 jint ergo_result = Arguments::apply_ergo();
3339 if (ergo_result != JNI_OK) return ergo_result;
3340
3341 if (PauseAtStartup) {
3342 os::pause();
3343 }
3344
3345 #ifndef USDT2
3346 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3347 #else /* USDT2 */
3348 HOTSPOT_VM_INIT_BEGIN();
3349 #endif /* USDT2 */
3350
3351 // Record VM creation timing statistics
3352 TraceVmCreationTime create_vm_timer;
3353 create_vm_timer.start();
3354
3355 // Timing (must come after argument parsing)
3356 TraceTime timer("Create VM", TraceStartupTime);
3357
3358 // Initialize the os module after parsing the args
3359 jint os_init_2_result = os::init_2();
3360 if (os_init_2_result != JNI_OK) return os_init_2_result;
3361
3362 jint adjust_after_os_result = Arguments::adjust_after_os();
3363 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3364
3365 // intialize TLS
3366 ThreadLocalStorage::init();
3367
3368 // Bootstrap native memory tracking, so it can start recording memory
3369 // activities before worker thread is started. This is the first phase
3370 // of bootstrapping, VM is currently running in single-thread mode.
3371 MemTracker::bootstrap_single_thread();
3372
3373 // Initialize output stream logging
3374 ostream_init_log();
3375
3376 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3377 // Must be before create_vm_init_agents()
3378 if (Arguments::init_libraries_at_startup()) {
3379 convert_vm_init_libraries_to_agents();
3380 }
3381
3382 // Launch -agentlib/-agentpath and converted -Xrun agents
3383 if (Arguments::init_agents_at_startup()) {
3384 create_vm_init_agents();
3385 }
3386
3387 // Initialize Threads state
3388 _thread_list = NULL;
3389 _number_of_threads = 0;
3390 _number_of_non_daemon_threads = 0;
3391
3392 // Initialize global data structures and create system classes in heap
3393 vm_init_globals();
3394
3395 // Attach the main thread to this os thread
3396 JavaThread* main_thread = new JavaThread();
3397 main_thread->set_thread_state(_thread_in_vm);
3398 // must do this before set_active_handles and initialize_thread_local_storage
3399 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3400 // change the stack size recorded here to one based on the java thread
3401 // stacksize. This adjusted size is what is used to figure the placement
3402 // of the guard pages.
3403 main_thread->record_stack_base_and_size();
3404 main_thread->initialize_thread_local_storage();
3405
3406 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3407
3408 if (!main_thread->set_as_starting_thread()) {
3409 vm_shutdown_during_initialization(
3410 "Failed necessary internal allocation. Out of swap space");
3411 delete main_thread;
3412 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3413 return JNI_ENOMEM;
3414 }
3415
3416 // Enable guard page *after* os::create_main_thread(), otherwise it would
3417 // crash Linux VM, see notes in os_linux.cpp.
3418 main_thread->create_stack_guard_pages();
3419
3420 // Initialize Java-Level synchronization subsystem
3421 ObjectMonitor::Initialize() ;
3422
3423 // Second phase of bootstrapping, VM is about entering multi-thread mode
3424 MemTracker::bootstrap_multi_thread();
3425
3426 // Initialize global modules
3427 jint status = init_globals();
3428 if (status != JNI_OK) {
3429 delete main_thread;
3430 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3431 return status;
3432 }
3433
3434 // Should be done after the heap is fully created
3435 main_thread->cache_global_variables();
3436
3437 HandleMark hm;
3438
3439 { MutexLocker mu(Threads_lock);
3440 Threads::add(main_thread);
3441 }
3442
3443 // Any JVMTI raw monitors entered in onload will transition into
3444 // real raw monitor. VM is setup enough here for raw monitor enter.
3445 JvmtiExport::transition_pending_onload_raw_monitors();
3446
3447 // Fully start NMT
3448 MemTracker::start();
3449
3450 // Create the VMThread
3451 { TraceTime timer("Start VMThread", TraceStartupTime);
3452 VMThread::create();
3453 Thread* vmthread = VMThread::vm_thread();
3454
3455 if (!os::create_thread(vmthread, os::vm_thread))
3456 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3457
3458 // Wait for the VM thread to become ready, and VMThread::run to initialize
3459 // Monitors can have spurious returns, must always check another state flag
3460 {
3461 MutexLocker ml(Notify_lock);
3462 os::start_thread(vmthread);
3463 while (vmthread->active_handles() == NULL) {
3464 Notify_lock->wait();
3465 }
3466 }
3467 }
3468
3469 assert (Universe::is_fully_initialized(), "not initialized");
3470 if (VerifyDuringStartup) {
3471 // Make sure we're starting with a clean slate.
3472 VM_Verify verify_op;
3473 VMThread::execute(&verify_op);
3474 }
3475
3476 EXCEPTION_MARK;
3477
3478 // At this point, the Universe is initialized, but we have not executed
3479 // any byte code. Now is a good time (the only time) to dump out the
3480 // internal state of the JVM for sharing.
3481 if (DumpSharedSpaces) {
3482 MetaspaceShared::preload_and_dump(CHECK_0);
3483 ShouldNotReachHere();
3484 }
3485
3486 // Always call even when there are not JVMTI environments yet, since environments
3487 // may be attached late and JVMTI must track phases of VM execution
3488 JvmtiExport::enter_start_phase();
3489
3490 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3491 JvmtiExport::post_vm_start();
3492
3493 {
3494 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3495
3496 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3497 create_vm_init_libraries();
3498 }
3499
3500 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3501
3502 // Initialize java_lang.System (needed before creating the thread)
3503 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3504 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3505 Handle thread_group = create_initial_thread_group(CHECK_0);
3506 Universe::set_main_thread_group(thread_group());
3507 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3508 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3509 main_thread->set_threadObj(thread_object);
3510 // Set thread status to running since main thread has
3511 // been started and running.
3512 java_lang_Thread::set_thread_status(thread_object,
3513 java_lang_Thread::RUNNABLE);
3514
3515 // The VM creates & returns objects of this class. Make sure it's initialized.
3516 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3517
3518 // The VM preresolves methods to these classes. Make sure that they get initialized
3519 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3520 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3521 call_initializeSystemClass(CHECK_0);
3522
3523 // get the Java runtime name after java.lang.System is initialized
3524 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3525 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3526
3527 // an instance of OutOfMemory exception has been allocated earlier
3528 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3529 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3530 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3531 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3532 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3533 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3534 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3535 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3536 }
3537
3538 // See : bugid 4211085.
3539 // Background : the static initializer of java.lang.Compiler tries to read
3540 // property"java.compiler" and read & write property "java.vm.info".
3541 // When a security manager is installed through the command line
3542 // option "-Djava.security.manager", the above properties are not
3543 // readable and the static initializer for java.lang.Compiler fails
3544 // resulting in a NoClassDefFoundError. This can happen in any
3545 // user code which calls methods in java.lang.Compiler.
3546 // Hack : the hack is to pre-load and initialize this class, so that only
3547 // system domains are on the stack when the properties are read.
3548 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3549 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3550 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3551 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3552 // Once that is done, we should remove this hack.
3553 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3554
3555 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3556 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3557 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3558 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3559 // This should also be taken out as soon as 4211383 gets fixed.
3560 reset_vm_info_property(CHECK_0);
3561
3562 quicken_jni_functions();
3563
3564 // Must be run after init_ft which initializes ft_enabled
3565 if (TRACE_INITIALIZE() != JNI_OK) {
3566 vm_exit_during_initialization("Failed to initialize tracing backend");
3567 }
3568
3569 // Set flag that basic initialization has completed. Used by exceptions and various
3570 // debug stuff, that does not work until all basic classes have been initialized.
3571 set_init_completed();
3572
3573 #ifndef USDT2
3574 HS_DTRACE_PROBE(hotspot, vm__init__end);
3575 #else /* USDT2 */
3576 HOTSPOT_VM_INIT_END();
3577 #endif /* USDT2 */
3578
3579 // record VM initialization completion time
3580 #if INCLUDE_MANAGEMENT
3581 Management::record_vm_init_completed();
3582 #endif // INCLUDE_MANAGEMENT
3583
3584 // Compute system loader. Note that this has to occur after set_init_completed, since
3585 // valid exceptions may be thrown in the process.
3586 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3587 // set_init_completed has just been called, causing exceptions not to be shortcut
3588 // anymore. We call vm_exit_during_initialization directly instead.
3589 SystemDictionary::compute_java_system_loader(THREAD);
3590 if (HAS_PENDING_EXCEPTION) {
3591 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3592 }
3593
3594 #if INCLUDE_ALL_GCS
3595 // Support for ConcurrentMarkSweep. This should be cleaned up
3596 // and better encapsulated. The ugly nested if test would go away
3597 // once things are properly refactored. XXX YSR
3598 if (UseConcMarkSweepGC || UseG1GC) {
3599 if (UseConcMarkSweepGC) {
3600 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3601 } else {
3602 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3603 }
3604 if (HAS_PENDING_EXCEPTION) {
3605 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3606 }
3607 }
3608 #endif // INCLUDE_ALL_GCS
3609
3610 // Always call even when there are not JVMTI environments yet, since environments
3611 // may be attached late and JVMTI must track phases of VM execution
3612 JvmtiExport::enter_live_phase();
3613
3614 // Signal Dispatcher needs to be started before VMInit event is posted
3615 os::signal_init();
3616
3617 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3618 if (!DisableAttachMechanism) {
3619 AttachListener::vm_start();
3620 if (StartAttachListener || AttachListener::init_at_startup()) {
3621 AttachListener::init();
3622 }
3623 }
3624
3625 // Launch -Xrun agents
3626 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3627 // back-end can launch with -Xdebug -Xrunjdwp.
3628 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3629 create_vm_init_libraries();
3630 }
3631
3632 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3633 JvmtiExport::post_vm_initialized();
3634
3635 if (TRACE_START() != JNI_OK) {
3636 vm_exit_during_initialization("Failed to start tracing backend.");
3637 }
3638
3639 if (CleanChunkPoolAsync) {
3640 Chunk::start_chunk_pool_cleaner_task();
3641 }
3642
3643 // initialize compiler(s)
3644 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3645 CompileBroker::compilation_init();
3646 #endif
3647
3648 if (EnableInvokeDynamic) {
3649 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3650 // It is done after compilers are initialized, because otherwise compilations of
3651 // signature polymorphic MH intrinsics can be missed
3652 // (see SystemDictionary::find_method_handle_intrinsic).
3653 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3654 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3655 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3656 }
3657
3658 #if INCLUDE_MANAGEMENT
3659 Management::initialize(THREAD);
3660 #endif // INCLUDE_MANAGEMENT
3661
3662 if (HAS_PENDING_EXCEPTION) {
3663 // management agent fails to start possibly due to
3664 // configuration problem and is responsible for printing
3665 // stack trace if appropriate. Simply exit VM.
3666 vm_exit(1);
3667 }
3668
3669 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3670 if (MemProfiling) MemProfiler::engage();
3671 StatSampler::engage();
3672 if (CheckJNICalls) JniPeriodicChecker::engage();
3673
3674 BiasedLocking::init();
3675
3676 #if INCLUDE_RTM_OPT
3677 RTMLockingCounters::init();
3678 #endif
3679
3680 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3681 call_postVMInitHook(THREAD);
3682 // The Java side of PostVMInitHook.run must deal with all
3683 // exceptions and provide means of diagnosis.
3684 if (HAS_PENDING_EXCEPTION) {
3685 CLEAR_PENDING_EXCEPTION;
3686 }
3687 }
3688
3689 {
3690 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3691 // Make sure the watcher thread can be started by WatcherThread::start()
3692 // or by dynamic enrollment.
3693 WatcherThread::make_startable();
3694 // Start up the WatcherThread if there are any periodic tasks
3695 // NOTE: All PeriodicTasks should be registered by now. If they
3696 // aren't, late joiners might appear to start slowly (we might
3697 // take a while to process their first tick).
3698 if (PeriodicTask::num_tasks() > 0) {
3699 WatcherThread::start();
3700 }
3701 }
3702
3703 // Give os specific code one last chance to start
3704 os::init_3();
3705
3706 create_vm_timer.end();
3707 #ifdef ASSERT
3708 _vm_complete = true;
3709 #endif
3710 return JNI_OK;
3711 }
3712
3713 // type for the Agent_OnLoad and JVM_OnLoad entry points
3714 extern "C" {
3715 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3716 }
3717 // Find a command line agent library and return its entry point for
3718 // -agentlib: -agentpath: -Xrun
3719 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3720 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3721 OnLoadEntry_t on_load_entry = NULL;
3722 void *library = NULL;
3723
3724 if (!agent->valid()) {
3725 char buffer[JVM_MAXPATHLEN];
3726 char ebuf[1024];
3727 const char *name = agent->name();
3728 const char *msg = "Could not find agent library ";
3729
3730 // First check to see if agent is statically linked into executable
3731 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3732 library = agent->os_lib();
3733 } else if (agent->is_absolute_path()) {
3734 library = os::dll_load(name, ebuf, sizeof ebuf);
3735 if (library == NULL) {
3736 const char *sub_msg = " in absolute path, with error: ";
3737 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3738 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3739 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3740 // If we can't find the agent, exit.
3741 vm_exit_during_initialization(buf, NULL);
3742 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3743 }
3744 } else {
3745 // Try to load the agent from the standard dll directory
3746 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3747 name)) {
3748 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3749 }
3750 if (library == NULL) { // Try the local directory
3751 char ns[1] = {0};
3752 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3753 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3754 }
3755 if (library == NULL) {
3756 const char *sub_msg = " on the library path, with error: ";
3757 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3758 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3759 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3760 // If we can't find the agent, exit.
3761 vm_exit_during_initialization(buf, NULL);
3762 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3763 }
3764 }
3765 }
3766 agent->set_os_lib(library);
3767 agent->set_valid();
3768 }
3769
3770 // Find the OnLoad function.
3771 on_load_entry =
3772 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3773 false,
3774 on_load_symbols,
3775 num_symbol_entries));
3776 return on_load_entry;
3777 }
3778
3779 // Find the JVM_OnLoad entry point
3780 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3781 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3782 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3783 }
3784
3785 // Find the Agent_OnLoad entry point
3786 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3787 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3788 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3789 }
3790
3791 // For backwards compatibility with -Xrun
3792 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3793 // treated like -agentpath:
3794 // Must be called before agent libraries are created
3795 void Threads::convert_vm_init_libraries_to_agents() {
3796 AgentLibrary* agent;
3797 AgentLibrary* next;
3798
3799 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3800 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3801 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3802
3803 // If there is an JVM_OnLoad function it will get called later,
3804 // otherwise see if there is an Agent_OnLoad
3805 if (on_load_entry == NULL) {
3806 on_load_entry = lookup_agent_on_load(agent);
3807 if (on_load_entry != NULL) {
3808 // switch it to the agent list -- so that Agent_OnLoad will be called,
3809 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3810 Arguments::convert_library_to_agent(agent);
3811 } else {
3812 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3813 }
3814 }
3815 }
3816 }
3817
3818 // Create agents for -agentlib: -agentpath: and converted -Xrun
3819 // Invokes Agent_OnLoad
3820 // Called very early -- before JavaThreads exist
3821 void Threads::create_vm_init_agents() {
3822 extern struct JavaVM_ main_vm;
3823 AgentLibrary* agent;
3824
3825 JvmtiExport::enter_onload_phase();
3826
3827 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3828 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3829
3830 if (on_load_entry != NULL) {
3831 // Invoke the Agent_OnLoad function
3832 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3833 if (err != JNI_OK) {
3834 vm_exit_during_initialization("agent library failed to init", agent->name());
3835 }
3836 } else {
3837 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3838 }
3839 }
3840 JvmtiExport::enter_primordial_phase();
3841 }
3842
3843 extern "C" {
3844 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3845 }
3846
3847 void Threads::shutdown_vm_agents() {
3848 // Send any Agent_OnUnload notifications
3849 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3850 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3851 extern struct JavaVM_ main_vm;
3852 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3853
3854 // Find the Agent_OnUnload function.
3855 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3856 os::find_agent_function(agent,
3857 false,
3858 on_unload_symbols,
3859 num_symbol_entries));
3860
3861 // Invoke the Agent_OnUnload function
3862 if (unload_entry != NULL) {
3863 JavaThread* thread = JavaThread::current();
3864 ThreadToNativeFromVM ttn(thread);
3865 HandleMark hm(thread);
3866 (*unload_entry)(&main_vm);
3867 }
3868 }
3869 }
3870
3871 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3872 // Invokes JVM_OnLoad
3873 void Threads::create_vm_init_libraries() {
3874 extern struct JavaVM_ main_vm;
3875 AgentLibrary* agent;
3876
3877 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3878 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3879
3880 if (on_load_entry != NULL) {
3881 // Invoke the JVM_OnLoad function
3882 JavaThread* thread = JavaThread::current();
3883 ThreadToNativeFromVM ttn(thread);
3884 HandleMark hm(thread);
3885 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3886 if (err != JNI_OK) {
3887 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3888 }
3889 } else {
3890 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3891 }
3892 }
3893 }
3894
3895 // Last thread running calls java.lang.Shutdown.shutdown()
3896 void JavaThread::invoke_shutdown_hooks() {
3897 HandleMark hm(this);
3898
3899 // We could get here with a pending exception, if so clear it now.
3900 if (this->has_pending_exception()) {
3901 this->clear_pending_exception();
3902 }
3903
3904 EXCEPTION_MARK;
3905 Klass* k =
3906 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3907 THREAD);
3908 if (k != NULL) {
3909 // SystemDictionary::resolve_or_null will return null if there was
3910 // an exception. If we cannot load the Shutdown class, just don't
3911 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3912 // and finalizers (if runFinalizersOnExit is set) won't be run.
3913 // Note that if a shutdown hook was registered or runFinalizersOnExit
3914 // was called, the Shutdown class would have already been loaded
3915 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3916 instanceKlassHandle shutdown_klass (THREAD, k);
3917 JavaValue result(T_VOID);
3918 JavaCalls::call_static(&result,
3919 shutdown_klass,
3920 vmSymbols::shutdown_method_name(),
3921 vmSymbols::void_method_signature(),
3922 THREAD);
3923 }
3924 CLEAR_PENDING_EXCEPTION;
3925 }
3926
3927 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3928 // the program falls off the end of main(). Another VM exit path is through
3929 // vm_exit() when the program calls System.exit() to return a value or when
3930 // there is a serious error in VM. The two shutdown paths are not exactly
3931 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3932 // and VM_Exit op at VM level.
3933 //
3934 // Shutdown sequence:
3935 // + Shutdown native memory tracking if it is on
3936 // + Wait until we are the last non-daemon thread to execute
3937 // <-- every thing is still working at this moment -->
3938 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3939 // shutdown hooks, run finalizers if finalization-on-exit
3940 // + Call before_exit(), prepare for VM exit
3941 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3942 // currently the only user of this mechanism is File.deleteOnExit())
3943 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3944 // post thread end and vm death events to JVMTI,
3945 // stop signal thread
3946 // + Call JavaThread::exit(), it will:
3947 // > release JNI handle blocks, remove stack guard pages
3948 // > remove this thread from Threads list
3949 // <-- no more Java code from this thread after this point -->
3950 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3951 // the compiler threads at safepoint
3952 // <-- do not use anything that could get blocked by Safepoint -->
3953 // + Disable tracing at JNI/JVM barriers
3954 // + Set _vm_exited flag for threads that are still running native code
3955 // + Delete this thread
3956 // + Call exit_globals()
3957 // > deletes tty
3958 // > deletes PerfMemory resources
3959 // + Return to caller
3960
3961 bool Threads::destroy_vm() {
3962 JavaThread* thread = JavaThread::current();
3963
3964 #ifdef ASSERT
3965 _vm_complete = false;
3966 #endif
3967 // Wait until we are the last non-daemon thread to execute
3968 { MutexLocker nu(Threads_lock);
3969 while (Threads::number_of_non_daemon_threads() > 1 )
3970 // This wait should make safepoint checks, wait without a timeout,
3971 // and wait as a suspend-equivalent condition.
3972 //
3973 // Note: If the FlatProfiler is running and this thread is waiting
3974 // for another non-daemon thread to finish, then the FlatProfiler
3975 // is waiting for the external suspend request on this thread to
3976 // complete. wait_for_ext_suspend_completion() will eventually
3977 // timeout, but that takes time. Making this wait a suspend-
3978 // equivalent condition solves that timeout problem.
3979 //
3980 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3981 Mutex::_as_suspend_equivalent_flag);
3982 }
3983
3984 // Hang forever on exit if we are reporting an error.
3985 if (ShowMessageBoxOnError && is_error_reported()) {
3986 os::infinite_sleep();
3987 }
3988 os::wait_for_keypress_at_exit();
3989
3990 if (JDK_Version::is_jdk12x_version()) {
3991 // We are the last thread running, so check if finalizers should be run.
3992 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3993 HandleMark rm(thread);
3994 Universe::run_finalizers_on_exit();
3995 } else {
3996 // run Java level shutdown hooks
3997 thread->invoke_shutdown_hooks();
3998 }
3999
4000 before_exit(thread);
4001
4002 thread->exit(true);
4003
4004 // Stop VM thread.
4005 {
4006 // 4945125 The vm thread comes to a safepoint during exit.
4007 // GC vm_operations can get caught at the safepoint, and the
4008 // heap is unparseable if they are caught. Grab the Heap_lock
4009 // to prevent this. The GC vm_operations will not be able to
4010 // queue until after the vm thread is dead.
4011 // After this point, we'll never emerge out of the safepoint before
4012 // the VM exits, so concurrent GC threads do not need to be explicitly
4013 // stopped; they remain inactive until the process exits.
4014 // Note: some concurrent G1 threads may be running during a safepoint,
4015 // but these will not be accessing the heap, just some G1-specific side
4016 // data structures that are not accessed by any other threads but them
4017 // after this point in a terminal safepoint.
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 p->set_safepoint_visible(true);
4092
4093 ThreadService::add_thread(p, daemon);
4094
4095 // Possible GC point.
4096 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4097 }
4098
4099 void Threads::remove(JavaThread* p) {
4100 // Extra scope needed for Thread_lock, so we can check
4101 // that we do not remove thread without safepoint code notice
4102 { MutexLocker ml(Threads_lock);
4103
4104 assert(includes(p), "p must be present");
4105
4106 JavaThread* current = _thread_list;
4107 JavaThread* prev = NULL;
4108
4109 while (current != p) {
4110 prev = current;
4111 current = current->next();
4112 }
4113
4114 if (prev) {
4115 prev->set_next(current->next());
4116 } else {
4117 _thread_list = p->next();
4118 }
4119 _number_of_threads--;
4120 oop threadObj = p->threadObj();
4121 bool daemon = true;
4122 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4123 _number_of_non_daemon_threads--;
4124 daemon = false;
4125
4126 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4127 // on destroy_vm will wake up.
4128 if (number_of_non_daemon_threads() == 1)
4129 Threads_lock->notify_all();
4130 }
4131 ThreadService::remove_thread(p, daemon);
4132
4133 // Make sure that safepoint code disregard this thread. This is needed since
4134 // the thread might mess around with locks after this point. This can cause it
4135 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4136 // of this thread since it is removed from the queue.
4137 p->set_terminated_value();
4138
4139 // Now, this thread is not visible to safepoint
4140 p->set_safepoint_visible(false);
4141 // once the thread becomes safepoint invisible, we can not use its per-thread
4142 // recorder. And Threads::do_threads() no longer walks this thread, so we have
4143 // to release its per-thread recorder here.
4144 MemTracker::thread_exiting(p);
4145 } // unlock Threads_lock
4146
4147 // Since Events::log uses a lock, we grab it outside the Threads_lock
4148 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4149 }
4150
4151 // Threads_lock must be held when this is called (or must be called during a safepoint)
4152 bool Threads::includes(JavaThread* p) {
4153 assert(Threads_lock->is_locked(), "sanity check");
4154 ALL_JAVA_THREADS(q) {
4155 if (q == p ) {
4156 return true;
4157 }
4158 }
4159 return false;
4160 }
4161
4162 // Operations on the Threads list for GC. These are not explicitly locked,
4163 // but the garbage collector must provide a safe context for them to run.
4164 // In particular, these things should never be called when the Threads_lock
4165 // is held by some other thread. (Note: the Safepoint abstraction also
4166 // uses the Threads_lock to gurantee this property. It also makes sure that
4167 // all threads gets blocked when exiting or starting).
4168
4169 void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4170 ALL_JAVA_THREADS(p) {
4171 p->oops_do(f, cld_f, cf);
4172 }
4173 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4174 }
4175
4176 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4177 // Introduce a mechanism allowing parallel threads to claim threads as
4178 // root groups. Overhead should be small enough to use all the time,
4179 // even in sequential code.
4180 SharedHeap* sh = SharedHeap::heap();
4181 // Cannot yet substitute active_workers for n_par_threads
4182 // because of G1CollectedHeap::verify() use of
4183 // SharedHeap::process_strong_roots(). n_par_threads == 0 will
4184 // turn off parallelism in process_strong_roots while active_workers
4185 // is being used for parallelism elsewhere.
4186 bool is_par = sh->n_par_threads() > 0;
4187 assert(!is_par ||
4188 (SharedHeap::heap()->n_par_threads() ==
4189 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4190 int cp = SharedHeap::heap()->strong_roots_parity();
4191 ALL_JAVA_THREADS(p) {
4192 if (p->claim_oops_do(is_par, cp)) {
4193 p->oops_do(f, cld_f, cf);
4194 }
4195 }
4196 VMThread* vmt = VMThread::vm_thread();
4197 if (vmt->claim_oops_do(is_par, cp)) {
4198 vmt->oops_do(f, cld_f, cf);
4199 }
4200 }
4201
4202 #if INCLUDE_ALL_GCS
4203 // Used by ParallelScavenge
4204 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4205 ALL_JAVA_THREADS(p) {
4206 q->enqueue(new ThreadRootsTask(p));
4207 }
4208 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4209 }
4210
4211 // Used by Parallel Old
4212 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4213 ALL_JAVA_THREADS(p) {
4214 q->enqueue(new ThreadRootsMarkingTask(p));
4215 }
4216 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4217 }
4218 #endif // INCLUDE_ALL_GCS
4219
4220 void Threads::nmethods_do(CodeBlobClosure* cf) {
4221 ALL_JAVA_THREADS(p) {
4222 p->nmethods_do(cf);
4223 }
4224 VMThread::vm_thread()->nmethods_do(cf);
4225 }
4226
4227 void Threads::metadata_do(void f(Metadata*)) {
4228 ALL_JAVA_THREADS(p) {
4229 p->metadata_do(f);
4230 }
4231 }
4232
4233 void Threads::gc_epilogue() {
4234 ALL_JAVA_THREADS(p) {
4235 p->gc_epilogue();
4236 }
4237 }
4238
4239 void Threads::gc_prologue() {
4240 ALL_JAVA_THREADS(p) {
4241 p->gc_prologue();
4242 }
4243 }
4244
4245 void Threads::deoptimized_wrt_marked_nmethods() {
4246 ALL_JAVA_THREADS(p) {
4247 p->deoptimized_wrt_marked_nmethods();
4248 }
4249 }
4250
4251
4252 // Get count Java threads that are waiting to enter the specified monitor.
4253 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4254 address monitor, bool doLock) {
4255 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4256 "must grab Threads_lock or be at safepoint");
4257 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4258
4259 int i = 0;
4260 {
4261 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4262 ALL_JAVA_THREADS(p) {
4263 if (p->is_Compiler_thread()) continue;
4264
4265 address pending = (address)p->current_pending_monitor();
4266 if (pending == monitor) { // found a match
4267 if (i < count) result->append(p); // save the first count matches
4268 i++;
4269 }
4270 }
4271 }
4272 return result;
4273 }
4274
4275
4276 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4277 assert(doLock ||
4278 Threads_lock->owned_by_self() ||
4279 SafepointSynchronize::is_at_safepoint(),
4280 "must grab Threads_lock or be at safepoint");
4281
4282 // NULL owner means not locked so we can skip the search
4283 if (owner == NULL) return NULL;
4284
4285 {
4286 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4287 ALL_JAVA_THREADS(p) {
4288 // first, see if owner is the address of a Java thread
4289 if (owner == (address)p) return p;
4290 }
4291 }
4292 // Cannot assert on lack of success here since this function may be
4293 // used by code that is trying to report useful problem information
4294 // like deadlock detection.
4295 if (UseHeavyMonitors) return NULL;
4296
4297 //
4298 // If we didn't find a matching Java thread and we didn't force use of
4299 // heavyweight monitors, then the owner is the stack address of the
4300 // Lock Word in the owning Java thread's stack.
4301 //
4302 JavaThread* the_owner = NULL;
4303 {
4304 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4305 ALL_JAVA_THREADS(q) {
4306 if (q->is_lock_owned(owner)) {
4307 the_owner = q;
4308 break;
4309 }
4310 }
4311 }
4312 // cannot assert on lack of success here; see above comment
4313 return the_owner;
4314 }
4315
4316 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4317 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4318 char buf[32];
4319 st->print_cr(os::local_time_string(buf, sizeof(buf)));
4320
4321 st->print_cr("Full thread dump %s (%s %s):",
4322 Abstract_VM_Version::vm_name(),
4323 Abstract_VM_Version::vm_release(),
4324 Abstract_VM_Version::vm_info_string()
4325 );
4326 st->cr();
4327
4328 #if INCLUDE_ALL_GCS
4329 // Dump concurrent locks
4330 ConcurrentLocksDump concurrent_locks;
4331 if (print_concurrent_locks) {
4332 concurrent_locks.dump_at_safepoint();
4333 }
4334 #endif // INCLUDE_ALL_GCS
4335
4336 ALL_JAVA_THREADS(p) {
4337 ResourceMark rm;
4338 p->print_on(st);
4339 if (print_stacks) {
4340 if (internal_format) {
4341 p->trace_stack();
4342 } else {
4343 p->print_stack_on(st);
4344 }
4345 }
4346 st->cr();
4347 #if INCLUDE_ALL_GCS
4348 if (print_concurrent_locks) {
4349 concurrent_locks.print_locks_on(p, st);
4350 }
4351 #endif // INCLUDE_ALL_GCS
4352 }
4353
4354 VMThread::vm_thread()->print_on(st);
4355 st->cr();
4356 Universe::heap()->print_gc_threads_on(st);
4357 WatcherThread* wt = WatcherThread::watcher_thread();
4358 if (wt != NULL) {
4359 wt->print_on(st);
4360 st->cr();
4361 }
4362 CompileBroker::print_compiler_threads_on(st);
4363 st->flush();
4364 }
4365
4366 // Threads::print_on_error() is called by fatal error handler. It's possible
4367 // that VM is not at safepoint and/or current thread is inside signal handler.
4368 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4369 // memory (even in resource area), it might deadlock the error handler.
4370 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4371 bool found_current = false;
4372 st->print_cr("Java Threads: ( => current thread )");
4373 ALL_JAVA_THREADS(thread) {
4374 bool is_current = (current == thread);
4375 found_current = found_current || is_current;
4376
4377 st->print("%s", is_current ? "=>" : " ");
4378
4379 st->print(PTR_FORMAT, thread);
4380 st->print(" ");
4381 thread->print_on_error(st, buf, buflen);
4382 st->cr();
4383 }
4384 st->cr();
4385
4386 st->print_cr("Other Threads:");
4387 if (VMThread::vm_thread()) {
4388 bool is_current = (current == VMThread::vm_thread());
4389 found_current = found_current || is_current;
4390 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4391
4392 st->print(PTR_FORMAT, VMThread::vm_thread());
4393 st->print(" ");
4394 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4395 st->cr();
4396 }
4397 WatcherThread* wt = WatcherThread::watcher_thread();
4398 if (wt != NULL) {
4399 bool is_current = (current == wt);
4400 found_current = found_current || is_current;
4401 st->print("%s", is_current ? "=>" : " ");
4402
4403 st->print(PTR_FORMAT, wt);
4404 st->print(" ");
4405 wt->print_on_error(st, buf, buflen);
4406 st->cr();
4407 }
4408 if (!found_current) {
4409 st->cr();
4410 st->print("=>" PTR_FORMAT " (exited) ", current);
4411 current->print_on_error(st, buf, buflen);
4412 st->cr();
4413 }
4414 }
4415
4416 // Internal SpinLock and Mutex
4417 // Based on ParkEvent
4418
4419 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4420 //
4421 // We employ SpinLocks _only for low-contention, fixed-length
4422 // short-duration critical sections where we're concerned
4423 // about native mutex_t or HotSpot Mutex:: latency.
4424 // The mux construct provides a spin-then-block mutual exclusion
4425 // mechanism.
4426 //
4427 // Testing has shown that contention on the ListLock guarding gFreeList
4428 // is common. If we implement ListLock as a simple SpinLock it's common
4429 // for the JVM to devolve to yielding with little progress. This is true
4430 // despite the fact that the critical sections protected by ListLock are
4431 // extremely short.
4432 //
4433 // TODO-FIXME: ListLock should be of type SpinLock.
4434 // We should make this a 1st-class type, integrated into the lock
4435 // hierarchy as leaf-locks. Critically, the SpinLock structure
4436 // should have sufficient padding to avoid false-sharing and excessive
4437 // cache-coherency traffic.
4438
4439
4440 typedef volatile int SpinLockT ;
4441
4442 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4443 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4444 return ; // normal fast-path return
4445 }
4446
4447 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4448 TEVENT (SpinAcquire - ctx) ;
4449 int ctr = 0 ;
4450 int Yields = 0 ;
4451 for (;;) {
4452 while (*adr != 0) {
4453 ++ctr ;
4454 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4455 if (Yields > 5) {
4456 os::naked_short_sleep(1);
4457 } else {
4458 os::NakedYield() ;
4459 ++Yields ;
4460 }
4461 } else {
4462 SpinPause() ;
4463 }
4464 }
4465 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4466 }
4467 }
4468
4469 void Thread::SpinRelease (volatile int * adr) {
4470 assert (*adr != 0, "invariant") ;
4471 OrderAccess::fence() ; // guarantee at least release consistency.
4472 // Roach-motel semantics.
4473 // It's safe if subsequent LDs and STs float "up" into the critical section,
4474 // but prior LDs and STs within the critical section can't be allowed
4475 // to reorder or float past the ST that releases the lock.
4476 *adr = 0 ;
4477 }
4478
4479 // muxAcquire and muxRelease:
4480 //
4481 // * muxAcquire and muxRelease support a single-word lock-word construct.
4482 // The LSB of the word is set IFF the lock is held.
4483 // The remainder of the word points to the head of a singly-linked list
4484 // of threads blocked on the lock.
4485 //
4486 // * The current implementation of muxAcquire-muxRelease uses its own
4487 // dedicated Thread._MuxEvent instance. If we're interested in
4488 // minimizing the peak number of extant ParkEvent instances then
4489 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4490 // as certain invariants were satisfied. Specifically, care would need
4491 // to be taken with regards to consuming unpark() "permits".
4492 // A safe rule of thumb is that a thread would never call muxAcquire()
4493 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4494 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4495 // consume an unpark() permit intended for monitorenter, for instance.
4496 // One way around this would be to widen the restricted-range semaphore
4497 // implemented in park(). Another alternative would be to provide
4498 // multiple instances of the PlatformEvent() for each thread. One
4499 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4500 //
4501 // * Usage:
4502 // -- Only as leaf locks
4503 // -- for short-term locking only as muxAcquire does not perform
4504 // thread state transitions.
4505 //
4506 // Alternatives:
4507 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4508 // but with parking or spin-then-park instead of pure spinning.
4509 // * Use Taura-Oyama-Yonenzawa locks.
4510 // * It's possible to construct a 1-0 lock if we encode the lockword as
4511 // (List,LockByte). Acquire will CAS the full lockword while Release
4512 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4513 // acquiring threads use timers (ParkTimed) to detect and recover from
4514 // the stranding window. Thread/Node structures must be aligned on 256-byte
4515 // boundaries by using placement-new.
4516 // * Augment MCS with advisory back-link fields maintained with CAS().
4517 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4518 // The validity of the backlinks must be ratified before we trust the value.
4519 // If the backlinks are invalid the exiting thread must back-track through the
4520 // the forward links, which are always trustworthy.
4521 // * Add a successor indication. The LockWord is currently encoded as
4522 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4523 // to provide the usual futile-wakeup optimization.
4524 // See RTStt for details.
4525 // * Consider schedctl.sc_nopreempt to cover the critical section.
4526 //
4527
4528
4529 typedef volatile intptr_t MutexT ; // Mux Lock-word
4530 enum MuxBits { LOCKBIT = 1 } ;
4531
4532 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4533 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4534 if (w == 0) return ;
4535 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4536 return ;
4537 }
4538
4539 TEVENT (muxAcquire - Contention) ;
4540 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4541 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4542 for (;;) {
4543 int its = (os::is_MP() ? 100 : 0) + 1 ;
4544
4545 // Optional spin phase: spin-then-park strategy
4546 while (--its >= 0) {
4547 w = *Lock ;
4548 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4549 return ;
4550 }
4551 }
4552
4553 Self->reset() ;
4554 Self->OnList = intptr_t(Lock) ;
4555 // The following fence() isn't _strictly necessary as the subsequent
4556 // CAS() both serializes execution and ratifies the fetched *Lock value.
4557 OrderAccess::fence();
4558 for (;;) {
4559 w = *Lock ;
4560 if ((w & LOCKBIT) == 0) {
4561 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4562 Self->OnList = 0 ; // hygiene - allows stronger asserts
4563 return ;
4564 }
4565 continue ; // Interference -- *Lock changed -- Just retry
4566 }
4567 assert (w & LOCKBIT, "invariant") ;
4568 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4569 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4570 }
4571
4572 while (Self->OnList != 0) {
4573 Self->park() ;
4574 }
4575 }
4576 }
4577
4578 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4579 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4580 if (w == 0) return ;
4581 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4582 return ;
4583 }
4584
4585 TEVENT (muxAcquire - Contention) ;
4586 ParkEvent * ReleaseAfter = NULL ;
4587 if (ev == NULL) {
4588 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4589 }
4590 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4591 for (;;) {
4592 guarantee (ev->OnList == 0, "invariant") ;
4593 int its = (os::is_MP() ? 100 : 0) + 1 ;
4594
4595 // Optional spin phase: spin-then-park strategy
4596 while (--its >= 0) {
4597 w = *Lock ;
4598 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4599 if (ReleaseAfter != NULL) {
4600 ParkEvent::Release (ReleaseAfter) ;
4601 }
4602 return ;
4603 }
4604 }
4605
4606 ev->reset() ;
4607 ev->OnList = intptr_t(Lock) ;
4608 // The following fence() isn't _strictly necessary as the subsequent
4609 // CAS() both serializes execution and ratifies the fetched *Lock value.
4610 OrderAccess::fence();
4611 for (;;) {
4612 w = *Lock ;
4613 if ((w & LOCKBIT) == 0) {
4614 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4615 ev->OnList = 0 ;
4616 // We call ::Release while holding the outer lock, thus
4617 // artificially lengthening the critical section.
4618 // Consider deferring the ::Release() until the subsequent unlock(),
4619 // after we've dropped the outer lock.
4620 if (ReleaseAfter != NULL) {
4621 ParkEvent::Release (ReleaseAfter) ;
4622 }
4623 return ;
4624 }
4625 continue ; // Interference -- *Lock changed -- Just retry
4626 }
4627 assert (w & LOCKBIT, "invariant") ;
4628 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4629 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4630 }
4631
4632 while (ev->OnList != 0) {
4633 ev->park() ;
4634 }
4635 }
4636 }
4637
4638 // Release() must extract a successor from the list and then wake that thread.
4639 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4640 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4641 // Release() would :
4642 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4643 // (B) Extract a successor from the private list "in-hand"
4644 // (C) attempt to CAS() the residual back into *Lock over null.
4645 // If there were any newly arrived threads and the CAS() would fail.
4646 // In that case Release() would detach the RATs, re-merge the list in-hand
4647 // with the RATs and repeat as needed. Alternately, Release() might
4648 // detach and extract a successor, but then pass the residual list to the wakee.
4649 // The wakee would be responsible for reattaching and remerging before it
4650 // competed for the lock.
4651 //
4652 // Both "pop" and DMR are immune from ABA corruption -- there can be
4653 // multiple concurrent pushers, but only one popper or detacher.
4654 // This implementation pops from the head of the list. This is unfair,
4655 // but tends to provide excellent throughput as hot threads remain hot.
4656 // (We wake recently run threads first).
4657
4658 void Thread::muxRelease (volatile intptr_t * Lock) {
4659 for (;;) {
4660 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4661 assert (w & LOCKBIT, "invariant") ;
4662 if (w == LOCKBIT) return ;
4663 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4664 assert (List != NULL, "invariant") ;
4665 assert (List->OnList == intptr_t(Lock), "invariant") ;
4666 ParkEvent * nxt = List->ListNext ;
4667
4668 // The following CAS() releases the lock and pops the head element.
4669 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4670 continue ;
4671 }
4672 List->OnList = 0 ;
4673 OrderAccess::fence() ;
4674 List->unpark () ;
4675 return ;
4676 }
4677 }
4678
4679
4680 void Threads::verify() {
4681 ALL_JAVA_THREADS(p) {
4682 p->verify();
4683 }
4684 VMThread* thread = VMThread::vm_thread();
4685 if (thread != NULL) thread->verify();
4686 }