1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jvmtifiles/jvmtiEnv.hpp"
36 #include "memory/gcLocker.inline.hpp"
37 #include "memory/metaspaceShared.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "memory/universe.inline.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/objArrayOop.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/symbol.hpp"
44 #include "prims/jvm_misc.hpp"
45 #include "prims/jvmtiExport.hpp"
46 #include "prims/jvmtiThreadState.hpp"
47 #include "prims/privilegedStack.hpp"
48 #include "runtime/arguments.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/deoptimization.hpp"
51 #include "runtime/fprofiler.hpp"
52 #include "runtime/frame.inline.hpp"
53 #include "runtime/init.hpp"
54 #include "runtime/interfaceSupport.hpp"
55 #include "runtime/java.hpp"
56 #include "runtime/javaCalls.hpp"
57 #include "runtime/jniPeriodicChecker.hpp"
58 #include "runtime/memprofiler.hpp"
59 #include "runtime/mutexLocker.hpp"
60 #include "runtime/objectMonitor.hpp"
61 #include "runtime/orderAccess.inline.hpp"
62 #include "runtime/osThread.hpp"
63 #include "runtime/safepoint.hpp"
64 #include "runtime/sharedRuntime.hpp"
65 #include "runtime/statSampler.hpp"
66 #include "runtime/stubRoutines.hpp"
67 #include "runtime/task.hpp"
68 #include "runtime/thread.inline.hpp"
69 #include "runtime/threadCritical.hpp"
70 #include "runtime/threadLocalStorage.hpp"
71 #include "runtime/vframe.hpp"
72 #include "runtime/vframeArray.hpp"
73 #include "runtime/vframe_hp.hpp"
74 #include "runtime/vmThread.hpp"
75 #include "runtime/vm_operations.hpp"
76 #include "services/attachListener.hpp"
77 #include "services/management.hpp"
78 #include "services/memTracker.hpp"
79 #include "services/threadService.hpp"
80 #include "trace/tracing.hpp"
81 #include "trace/traceMacros.hpp"
82 #include "utilities/defaultStream.hpp"
83 #include "utilities/dtrace.hpp"
84 #include "utilities/events.hpp"
85 #include "utilities/preserveException.hpp"
86 #include "utilities/macros.hpp"
87 #ifdef TARGET_OS_FAMILY_linux
88 # include "os_linux.inline.hpp"
89 #endif
90 #ifdef TARGET_OS_FAMILY_solaris
91 # include "os_solaris.inline.hpp"
92 #endif
93 #ifdef TARGET_OS_FAMILY_windows
94 # include "os_windows.inline.hpp"
95 #endif
96 #ifdef TARGET_OS_FAMILY_bsd
97 # include "os_bsd.inline.hpp"
98 #endif
99 #if INCLUDE_ALL_GCS
100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
102 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
103 #endif // INCLUDE_ALL_GCS
104 #ifdef COMPILER1
105 #include "c1/c1_Compiler.hpp"
106 #endif
107 #ifdef COMPILER2
108 #include "opto/c2compiler.hpp"
109 #include "opto/idealGraphPrinter.hpp"
110 #endif
111 #if INCLUDE_RTM_OPT
112 #include "runtime/rtmLocking.hpp"
113 #endif
114
115 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
116
117 #ifdef DTRACE_ENABLED
118
119 // Only bother with this argument setup if dtrace is available
120
121 #ifndef USDT2
122 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
123 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
124 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
125 intptr_t, intptr_t, bool);
126 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
127 intptr_t, intptr_t, bool);
128
129 #define DTRACE_THREAD_PROBE(probe, javathread) \
130 { \
131 ResourceMark rm(this); \
132 int len = 0; \
133 const char* name = (javathread)->get_thread_name(); \
134 len = strlen(name); \
135 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
136 name, len, \
137 java_lang_Thread::thread_id((javathread)->threadObj()), \
138 (javathread)->osthread()->thread_id(), \
139 java_lang_Thread::is_daemon((javathread)->threadObj())); \
140 }
141
142 #else /* USDT2 */
143
144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
146
147 #define DTRACE_THREAD_PROBE(probe, javathread) \
148 { \
149 ResourceMark rm(this); \
150 int len = 0; \
151 const char* name = (javathread)->get_thread_name(); \
152 len = strlen(name); \
153 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
154 (char *) name, len, \
155 java_lang_Thread::thread_id((javathread)->threadObj()), \
156 (uintptr_t) (javathread)->osthread()->thread_id(), \
157 java_lang_Thread::is_daemon((javathread)->threadObj())); \
158 }
159
160 #endif /* USDT2 */
161
162 #else // ndef DTRACE_ENABLED
163
164 #define DTRACE_THREAD_PROBE(probe, javathread)
165
166 #endif // ndef DTRACE_ENABLED
167
168
169 // Class hierarchy
170 // - Thread
171 // - VMThread
172 // - WatcherThread
173 // - ConcurrentMarkSweepThread
174 // - JavaThread
175 // - CompilerThread
176
177 // ======= Thread ========
178 // Support for forcing alignment of thread objects for biased locking
179 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
180 if (UseBiasedLocking) {
181 const int alignment = markOopDesc::biased_lock_alignment;
182 size_t aligned_size = size + (alignment - sizeof(intptr_t));
183 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
184 : AllocateHeap(aligned_size, flags, CURRENT_PC,
185 AllocFailStrategy::RETURN_NULL);
186 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
187 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
188 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
189 "JavaThread alignment code overflowed allocated storage");
190 if (TraceBiasedLocking) {
191 if (aligned_addr != real_malloc_addr)
192 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
193 real_malloc_addr, aligned_addr);
194 }
195 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
196 return aligned_addr;
197 } else {
198 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
199 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
200 }
201 }
202
203 void Thread::operator delete(void* p) {
204 if (UseBiasedLocking) {
205 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
206 FreeHeap(real_malloc_addr, mtThread);
207 } else {
208 FreeHeap(p, mtThread);
209 }
210 }
211
212
213 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
214 // JavaThread
215
216
217 Thread::Thread() {
218 // stack and get_thread
219 set_stack_base(NULL);
220 set_stack_size(0);
221 set_self_raw_id(0);
222 set_lgrp_id(-1);
223
224 // allocated data structures
225 set_osthread(NULL);
226 set_resource_area(new (mtThread)ResourceArea());
227 DEBUG_ONLY(_current_resource_mark = NULL;)
228 set_handle_area(new (mtThread) HandleArea(NULL));
229 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
230 set_active_handles(NULL);
231 set_free_handle_block(NULL);
232 set_last_handle_mark(NULL);
233
234 // This initial value ==> never claimed.
235 _oops_do_parity = 0;
236
237 _metadata_on_stack_buffer = NULL;
238
239 // the handle mark links itself to last_handle_mark
240 new HandleMark(this);
241
242 // plain initialization
243 debug_only(_owned_locks = NULL;)
244 debug_only(_allow_allocation_count = 0;)
245 NOT_PRODUCT(_allow_safepoint_count = 0;)
246 NOT_PRODUCT(_skip_gcalot = false;)
247 _jvmti_env_iteration_count = 0;
248 set_allocated_bytes(0);
249 _vm_operation_started_count = 0;
250 _vm_operation_completed_count = 0;
251 _current_pending_monitor = NULL;
252 _current_pending_monitor_is_from_java = true;
253 _current_waiting_monitor = NULL;
254 _num_nested_signal = 0;
255 omFreeList = NULL ;
256 omFreeCount = 0 ;
257 omFreeProvision = 32 ;
258 omInUseList = NULL ;
259 omInUseCount = 0 ;
260
261 #ifdef ASSERT
262 _visited_for_critical_count = false;
263 #endif
264
265 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
266 _suspend_flags = 0;
267
268 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
269 _hashStateX = os::random() ;
270 _hashStateY = 842502087 ;
271 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
272 _hashStateW = 273326509 ;
273
274 _OnTrap = 0 ;
275 _schedctl = NULL ;
276 _Stalled = 0 ;
277 _TypeTag = 0x2BAD ;
278
279 // Many of the following fields are effectively final - immutable
280 // Note that nascent threads can't use the Native Monitor-Mutex
281 // construct until the _MutexEvent is initialized ...
282 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
283 // we might instead use a stack of ParkEvents that we could provision on-demand.
284 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
285 // and ::Release()
286 _ParkEvent = ParkEvent::Allocate (this) ;
287 _SleepEvent = ParkEvent::Allocate (this) ;
288 _MutexEvent = ParkEvent::Allocate (this) ;
289 _MuxEvent = ParkEvent::Allocate (this) ;
290
291 #ifdef CHECK_UNHANDLED_OOPS
292 if (CheckUnhandledOops) {
293 _unhandled_oops = new UnhandledOops(this);
294 }
295 #endif // CHECK_UNHANDLED_OOPS
296 #ifdef ASSERT
297 if (UseBiasedLocking) {
298 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
299 assert(this == _real_malloc_address ||
300 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
301 "bug in forced alignment of thread objects");
302 }
303 #endif /* ASSERT */
304 }
305
306 void Thread::initialize_thread_local_storage() {
307 // Note: Make sure this method only calls
308 // non-blocking operations. Otherwise, it might not work
309 // with the thread-startup/safepoint interaction.
310
311 // During Java thread startup, safepoint code should allow this
312 // method to complete because it may need to allocate memory to
313 // store information for the new thread.
314
315 // initialize structure dependent on thread local storage
316 ThreadLocalStorage::set_thread(this);
317 }
318
319 void Thread::record_stack_base_and_size() {
320 set_stack_base(os::current_stack_base());
321 set_stack_size(os::current_stack_size());
322 if (is_Java_thread()) {
323 ((JavaThread*) this)->set_stack_overflow_limit();
324 }
325 // CR 7190089: on Solaris, primordial thread's stack is adjusted
326 // in initialize_thread(). Without the adjustment, stack size is
327 // incorrect if stack is set to unlimited (ulimit -s unlimited).
328 // So far, only Solaris has real implementation of initialize_thread().
329 //
330 // set up any platform-specific state.
331 os::initialize_thread(this);
332
333 #if INCLUDE_NMT
334 // record thread's native stack, stack grows downward
335 address stack_low_addr = stack_base() - stack_size();
336 MemTracker::record_thread_stack(stack_low_addr, stack_size());
337 #endif // INCLUDE_NMT
338 }
339
340
341 Thread::~Thread() {
342 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
343 ObjectSynchronizer::omFlush (this) ;
344
345 EVENT_THREAD_DESTRUCT(this);
346
347 // stack_base can be NULL if the thread is never started or exited before
348 // record_stack_base_and_size called. Although, we would like to ensure
349 // that all started threads do call record_stack_base_and_size(), there is
350 // not proper way to enforce that.
351 #if INCLUDE_NMT
352 if (_stack_base != NULL) {
353 address low_stack_addr = stack_base() - stack_size();
354 MemTracker::release_thread_stack(low_stack_addr, stack_size());
355 #ifdef ASSERT
356 set_stack_base(NULL);
357 #endif
358 }
359 #endif // INCLUDE_NMT
360
361 // deallocate data structures
362 delete resource_area();
363 // since the handle marks are using the handle area, we have to deallocated the root
364 // handle mark before deallocating the thread's handle area,
365 assert(last_handle_mark() != NULL, "check we have an element");
366 delete last_handle_mark();
367 assert(last_handle_mark() == NULL, "check we have reached the end");
368
369 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
370 // We NULL out the fields for good hygiene.
371 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
372 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
373 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
374 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
375
376 delete handle_area();
377 delete metadata_handles();
378
379 // osthread() can be NULL, if creation of thread failed.
380 if (osthread() != NULL) os::free_thread(osthread());
381
382 delete _SR_lock;
383
384 // clear thread local storage if the Thread is deleting itself
385 if (this == Thread::current()) {
386 ThreadLocalStorage::set_thread(NULL);
387 } else {
388 // In the case where we're not the current thread, invalidate all the
389 // caches in case some code tries to get the current thread or the
390 // thread that was destroyed, and gets stale information.
391 ThreadLocalStorage::invalidate_all();
392 }
393 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
394 }
395
396 // NOTE: dummy function for assertion purpose.
397 void Thread::run() {
398 ShouldNotReachHere();
399 }
400
401 #ifdef ASSERT
402 // Private method to check for dangling thread pointer
403 void check_for_dangling_thread_pointer(Thread *thread) {
404 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
405 "possibility of dangling Thread pointer");
406 }
407 #endif
408
409
410 #ifndef PRODUCT
411 // Tracing method for basic thread operations
412 void Thread::trace(const char* msg, const Thread* const thread) {
413 if (!TraceThreadEvents) return;
414 ResourceMark rm;
415 ThreadCritical tc;
416 const char *name = "non-Java thread";
417 int prio = -1;
418 if (thread->is_Java_thread()
419 && !thread->is_Compiler_thread()) {
420 // The Threads_lock must be held to get information about
421 // this thread but may not be in some situations when
422 // tracing thread events.
423 bool release_Threads_lock = false;
424 if (!Threads_lock->owned_by_self()) {
425 Threads_lock->lock();
426 release_Threads_lock = true;
427 }
428 JavaThread* jt = (JavaThread *)thread;
429 name = (char *)jt->get_thread_name();
430 oop thread_oop = jt->threadObj();
431 if (thread_oop != NULL) {
432 prio = java_lang_Thread::priority(thread_oop);
433 }
434 if (release_Threads_lock) {
435 Threads_lock->unlock();
436 }
437 }
438 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
439 }
440 #endif
441
442
443 ThreadPriority Thread::get_priority(const Thread* const thread) {
444 trace("get priority", thread);
445 ThreadPriority priority;
446 // Can return an error!
447 (void)os::get_priority(thread, priority);
448 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
449 return priority;
450 }
451
452 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
453 trace("set priority", thread);
454 debug_only(check_for_dangling_thread_pointer(thread);)
455 // Can return an error!
456 (void)os::set_priority(thread, priority);
457 }
458
459
460 void Thread::start(Thread* thread) {
461 trace("start", thread);
462 // Start is different from resume in that its safety is guaranteed by context or
463 // being called from a Java method synchronized on the Thread object.
464 if (!DisableStartThread) {
465 if (thread->is_Java_thread()) {
466 // Initialize the thread state to RUNNABLE before starting this thread.
467 // Can not set it after the thread started because we do not know the
468 // exact thread state at that time. It could be in MONITOR_WAIT or
469 // in SLEEPING or some other state.
470 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
471 java_lang_Thread::RUNNABLE);
472 }
473 os::start_thread(thread);
474 }
475 }
476
477 // Enqueue a VM_Operation to do the job for us - sometime later
478 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
479 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
480 VMThread::execute(vm_stop);
481 }
482
483
484 //
485 // Check if an external suspend request has completed (or has been
486 // cancelled). Returns true if the thread is externally suspended and
487 // false otherwise.
488 //
489 // The bits parameter returns information about the code path through
490 // the routine. Useful for debugging:
491 //
492 // set in is_ext_suspend_completed():
493 // 0x00000001 - routine was entered
494 // 0x00000010 - routine return false at end
495 // 0x00000100 - thread exited (return false)
496 // 0x00000200 - suspend request cancelled (return false)
497 // 0x00000400 - thread suspended (return true)
498 // 0x00001000 - thread is in a suspend equivalent state (return true)
499 // 0x00002000 - thread is native and walkable (return true)
500 // 0x00004000 - thread is native_trans and walkable (needed retry)
501 //
502 // set in wait_for_ext_suspend_completion():
503 // 0x00010000 - routine was entered
504 // 0x00020000 - suspend request cancelled before loop (return false)
505 // 0x00040000 - thread suspended before loop (return true)
506 // 0x00080000 - suspend request cancelled in loop (return false)
507 // 0x00100000 - thread suspended in loop (return true)
508 // 0x00200000 - suspend not completed during retry loop (return false)
509 //
510
511 // Helper class for tracing suspend wait debug bits.
512 //
513 // 0x00000100 indicates that the target thread exited before it could
514 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
515 // 0x00080000 each indicate a cancelled suspend request so they don't
516 // count as wait failures either.
517 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
518
519 class TraceSuspendDebugBits : public StackObj {
520 private:
521 JavaThread * jt;
522 bool is_wait;
523 bool called_by_wait; // meaningful when !is_wait
524 uint32_t * bits;
525
526 public:
527 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
528 uint32_t *_bits) {
529 jt = _jt;
530 is_wait = _is_wait;
531 called_by_wait = _called_by_wait;
532 bits = _bits;
533 }
534
535 ~TraceSuspendDebugBits() {
536 if (!is_wait) {
537 #if 1
538 // By default, don't trace bits for is_ext_suspend_completed() calls.
539 // That trace is very chatty.
540 return;
541 #else
542 if (!called_by_wait) {
543 // If tracing for is_ext_suspend_completed() is enabled, then only
544 // trace calls to it from wait_for_ext_suspend_completion()
545 return;
546 }
547 #endif
548 }
549
550 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
551 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
552 MutexLocker ml(Threads_lock); // needed for get_thread_name()
553 ResourceMark rm;
554
555 tty->print_cr(
556 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
557 jt->get_thread_name(), *bits);
558
559 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
560 }
561 }
562 }
563 };
564 #undef DEBUG_FALSE_BITS
565
566
567 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
568 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
569
570 bool did_trans_retry = false; // only do thread_in_native_trans retry once
571 bool do_trans_retry; // flag to force the retry
572
573 *bits |= 0x00000001;
574
575 do {
576 do_trans_retry = false;
577
578 if (is_exiting()) {
579 // Thread is in the process of exiting. This is always checked
580 // first to reduce the risk of dereferencing a freed JavaThread.
581 *bits |= 0x00000100;
582 return false;
583 }
584
585 if (!is_external_suspend()) {
586 // Suspend request is cancelled. This is always checked before
587 // is_ext_suspended() to reduce the risk of a rogue resume
588 // confusing the thread that made the suspend request.
589 *bits |= 0x00000200;
590 return false;
591 }
592
593 if (is_ext_suspended()) {
594 // thread is suspended
595 *bits |= 0x00000400;
596 return true;
597 }
598
599 // Now that we no longer do hard suspends of threads running
600 // native code, the target thread can be changing thread state
601 // while we are in this routine:
602 //
603 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
604 //
605 // We save a copy of the thread state as observed at this moment
606 // and make our decision about suspend completeness based on the
607 // copy. This closes the race where the thread state is seen as
608 // _thread_in_native_trans in the if-thread_blocked check, but is
609 // seen as _thread_blocked in if-thread_in_native_trans check.
610 JavaThreadState save_state = thread_state();
611
612 if (save_state == _thread_blocked && is_suspend_equivalent()) {
613 // If the thread's state is _thread_blocked and this blocking
614 // condition is known to be equivalent to a suspend, then we can
615 // consider the thread to be externally suspended. This means that
616 // the code that sets _thread_blocked has been modified to do
617 // self-suspension if the blocking condition releases. We also
618 // used to check for CONDVAR_WAIT here, but that is now covered by
619 // the _thread_blocked with self-suspension check.
620 //
621 // Return true since we wouldn't be here unless there was still an
622 // external suspend request.
623 *bits |= 0x00001000;
624 return true;
625 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
626 // Threads running native code will self-suspend on native==>VM/Java
627 // transitions. If its stack is walkable (should always be the case
628 // unless this function is called before the actual java_suspend()
629 // call), then the wait is done.
630 *bits |= 0x00002000;
631 return true;
632 } else if (!called_by_wait && !did_trans_retry &&
633 save_state == _thread_in_native_trans &&
634 frame_anchor()->walkable()) {
635 // The thread is transitioning from thread_in_native to another
636 // thread state. check_safepoint_and_suspend_for_native_trans()
637 // will force the thread to self-suspend. If it hasn't gotten
638 // there yet we may have caught the thread in-between the native
639 // code check above and the self-suspend. Lucky us. If we were
640 // called by wait_for_ext_suspend_completion(), then it
641 // will be doing the retries so we don't have to.
642 //
643 // Since we use the saved thread state in the if-statement above,
644 // there is a chance that the thread has already transitioned to
645 // _thread_blocked by the time we get here. In that case, we will
646 // make a single unnecessary pass through the logic below. This
647 // doesn't hurt anything since we still do the trans retry.
648
649 *bits |= 0x00004000;
650
651 // Once the thread leaves thread_in_native_trans for another
652 // thread state, we break out of this retry loop. We shouldn't
653 // need this flag to prevent us from getting back here, but
654 // sometimes paranoia is good.
655 did_trans_retry = true;
656
657 // We wait for the thread to transition to a more usable state.
658 for (int i = 1; i <= SuspendRetryCount; i++) {
659 // We used to do an "os::yield_all(i)" call here with the intention
660 // that yielding would increase on each retry. However, the parameter
661 // is ignored on Linux which means the yield didn't scale up. Waiting
662 // on the SR_lock below provides a much more predictable scale up for
663 // the delay. It also provides a simple/direct point to check for any
664 // safepoint requests from the VMThread
665
666 // temporarily drops SR_lock while doing wait with safepoint check
667 // (if we're a JavaThread - the WatcherThread can also call this)
668 // and increase delay with each retry
669 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
670
671 // check the actual thread state instead of what we saved above
672 if (thread_state() != _thread_in_native_trans) {
673 // the thread has transitioned to another thread state so
674 // try all the checks (except this one) one more time.
675 do_trans_retry = true;
676 break;
677 }
678 } // end retry loop
679
680
681 }
682 } while (do_trans_retry);
683
684 *bits |= 0x00000010;
685 return false;
686 }
687
688 //
689 // Wait for an external suspend request to complete (or be cancelled).
690 // Returns true if the thread is externally suspended and false otherwise.
691 //
692 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
693 uint32_t *bits) {
694 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
695 false /* !called_by_wait */, bits);
696
697 // local flag copies to minimize SR_lock hold time
698 bool is_suspended;
699 bool pending;
700 uint32_t reset_bits;
701
702 // set a marker so is_ext_suspend_completed() knows we are the caller
703 *bits |= 0x00010000;
704
705 // We use reset_bits to reinitialize the bits value at the top of
706 // each retry loop. This allows the caller to make use of any
707 // unused bits for their own marking purposes.
708 reset_bits = *bits;
709
710 {
711 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
712 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
713 delay, bits);
714 pending = is_external_suspend();
715 }
716 // must release SR_lock to allow suspension to complete
717
718 if (!pending) {
719 // A cancelled suspend request is the only false return from
720 // is_ext_suspend_completed() that keeps us from entering the
721 // retry loop.
722 *bits |= 0x00020000;
723 return false;
724 }
725
726 if (is_suspended) {
727 *bits |= 0x00040000;
728 return true;
729 }
730
731 for (int i = 1; i <= retries; i++) {
732 *bits = reset_bits; // reinit to only track last retry
733
734 // We used to do an "os::yield_all(i)" call here with the intention
735 // that yielding would increase on each retry. However, the parameter
736 // is ignored on Linux which means the yield didn't scale up. Waiting
737 // on the SR_lock below provides a much more predictable scale up for
738 // the delay. It also provides a simple/direct point to check for any
739 // safepoint requests from the VMThread
740
741 {
742 MutexLocker ml(SR_lock());
743 // wait with safepoint check (if we're a JavaThread - the WatcherThread
744 // can also call this) and increase delay with each retry
745 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
746
747 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
748 delay, bits);
749
750 // It is possible for the external suspend request to be cancelled
751 // (by a resume) before the actual suspend operation is completed.
752 // Refresh our local copy to see if we still need to wait.
753 pending = is_external_suspend();
754 }
755
756 if (!pending) {
757 // A cancelled suspend request is the only false return from
758 // is_ext_suspend_completed() that keeps us from staying in the
759 // retry loop.
760 *bits |= 0x00080000;
761 return false;
762 }
763
764 if (is_suspended) {
765 *bits |= 0x00100000;
766 return true;
767 }
768 } // end retry loop
769
770 // thread did not suspend after all our retries
771 *bits |= 0x00200000;
772 return false;
773 }
774
775 #ifndef PRODUCT
776 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
777
778 // This should not need to be atomic as the only way for simultaneous
779 // updates is via interrupts. Even then this should be rare or non-existant
780 // and we don't care that much anyway.
781
782 int index = _jmp_ring_index;
783 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
784 _jmp_ring[index]._target = (intptr_t) target;
785 _jmp_ring[index]._instruction = (intptr_t) instr;
786 _jmp_ring[index]._file = file;
787 _jmp_ring[index]._line = line;
788 }
789 #endif /* PRODUCT */
790
791 // Called by flat profiler
792 // Callers have already called wait_for_ext_suspend_completion
793 // The assertion for that is currently too complex to put here:
794 bool JavaThread::profile_last_Java_frame(frame* _fr) {
795 bool gotframe = false;
796 // self suspension saves needed state.
797 if (has_last_Java_frame() && _anchor.walkable()) {
798 *_fr = pd_last_frame();
799 gotframe = true;
800 }
801 return gotframe;
802 }
803
804 void Thread::interrupt(Thread* thread) {
805 trace("interrupt", thread);
806 debug_only(check_for_dangling_thread_pointer(thread);)
807 os::interrupt(thread);
808 }
809
810 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
811 trace("is_interrupted", thread);
812 debug_only(check_for_dangling_thread_pointer(thread);)
813 // Note: If clear_interrupted==false, this simply fetches and
814 // returns the value of the field osthread()->interrupted().
815 return os::is_interrupted(thread, clear_interrupted);
816 }
817
818
819 // GC Support
820 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
821 jint thread_parity = _oops_do_parity;
822 if (thread_parity != strong_roots_parity) {
823 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
824 if (res == thread_parity) {
825 return true;
826 } else {
827 guarantee(res == strong_roots_parity, "Or else what?");
828 assert(SharedHeap::heap()->workers()->active_workers() > 0,
829 "Should only fail when parallel.");
830 return false;
831 }
832 }
833 assert(SharedHeap::heap()->workers()->active_workers() > 0,
834 "Should only fail when parallel.");
835 return false;
836 }
837
838 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
839 active_handles()->oops_do(f);
840 // Do oop for ThreadShadow
841 f->do_oop((oop*)&_pending_exception);
842 handle_area()->oops_do(f);
843 }
844
845 void Thread::nmethods_do(CodeBlobClosure* cf) {
846 // no nmethods in a generic thread...
847 }
848
849 void Thread::metadata_do(void f(Metadata*)) {
850 if (metadata_handles() != NULL) {
851 for (int i = 0; i< metadata_handles()->length(); i++) {
852 f(metadata_handles()->at(i));
853 }
854 }
855 }
856
857 void Thread::print_on(outputStream* st) const {
858 // get_priority assumes osthread initialized
859 if (osthread() != NULL) {
860 int os_prio;
861 if (os::get_native_priority(this, &os_prio) == OS_OK) {
862 st->print("os_prio=%d ", os_prio);
863 }
864 st->print("tid=" INTPTR_FORMAT " ", this);
865 ext().print_on(st);
866 osthread()->print_on(st);
867 }
868 debug_only(if (WizardMode) print_owned_locks_on(st);)
869 }
870
871 // Thread::print_on_error() is called by fatal error handler. Don't use
872 // any lock or allocate memory.
873 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
874 if (is_VM_thread()) st->print("VMThread");
875 else if (is_Compiler_thread()) st->print("CompilerThread");
876 else if (is_Java_thread()) st->print("JavaThread");
877 else if (is_GC_task_thread()) st->print("GCTaskThread");
878 else if (is_Watcher_thread()) st->print("WatcherThread");
879 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
880 else st->print("Thread");
881
882 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
883 _stack_base - _stack_size, _stack_base);
884
885 if (osthread()) {
886 st->print(" [id=%d]", osthread()->thread_id());
887 }
888 }
889
890 #ifdef ASSERT
891 void Thread::print_owned_locks_on(outputStream* st) const {
892 Monitor *cur = _owned_locks;
893 if (cur == NULL) {
894 st->print(" (no locks) ");
895 } else {
896 st->print_cr(" Locks owned:");
897 while(cur) {
898 cur->print_on(st);
899 cur = cur->next();
900 }
901 }
902 }
903
904 static int ref_use_count = 0;
905
906 bool Thread::owns_locks_but_compiled_lock() const {
907 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
908 if (cur != Compile_lock) return true;
909 }
910 return false;
911 }
912
913
914 #endif
915
916 #ifndef PRODUCT
917
918 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
919 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
920 // no threads which allow_vm_block's are held
921 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
922 // Check if current thread is allowed to block at a safepoint
923 if (!(_allow_safepoint_count == 0))
924 fatal("Possible safepoint reached by thread that does not allow it");
925 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
926 fatal("LEAF method calling lock?");
927 }
928
929 #ifdef ASSERT
930 if (potential_vm_operation && is_Java_thread()
931 && !Universe::is_bootstrapping()) {
932 // Make sure we do not hold any locks that the VM thread also uses.
933 // This could potentially lead to deadlocks
934 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
935 // Threads_lock is special, since the safepoint synchronization will not start before this is
936 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
937 // since it is used to transfer control between JavaThreads and the VMThread
938 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
939 if ( (cur->allow_vm_block() &&
940 cur != Threads_lock &&
941 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
942 cur != VMOperationRequest_lock &&
943 cur != VMOperationQueue_lock) ||
944 cur->rank() == Mutex::special) {
945 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
946 }
947 }
948 }
949
950 if (GCALotAtAllSafepoints) {
951 // We could enter a safepoint here and thus have a gc
952 InterfaceSupport::check_gc_alot();
953 }
954 #endif
955 }
956 #endif
957
958 bool Thread::is_in_stack(address adr) const {
959 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
960 address end = os::current_stack_pointer();
961 // Allow non Java threads to call this without stack_base
962 if (_stack_base == NULL) return true;
963 if (stack_base() >= adr && adr >= end) return true;
964
965 return false;
966 }
967
968
969 bool Thread::is_in_usable_stack(address adr) const {
970 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
971 size_t usable_stack_size = _stack_size - stack_guard_size;
972
973 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
974 }
975
976
977 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
978 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
979 // used for compilation in the future. If that change is made, the need for these methods
980 // should be revisited, and they should be removed if possible.
981
982 bool Thread::is_lock_owned(address adr) const {
983 return on_local_stack(adr);
984 }
985
986 bool Thread::set_as_starting_thread() {
987 // NOTE: this must be called inside the main thread.
988 return os::create_main_thread((JavaThread*)this);
989 }
990
991 static void initialize_class(Symbol* class_name, TRAPS) {
992 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
993 InstanceKlass::cast(klass)->initialize(CHECK);
994 }
995
996
997 // Creates the initial ThreadGroup
998 static Handle create_initial_thread_group(TRAPS) {
999 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1000 instanceKlassHandle klass (THREAD, k);
1001
1002 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1003 {
1004 JavaValue result(T_VOID);
1005 JavaCalls::call_special(&result,
1006 system_instance,
1007 klass,
1008 vmSymbols::object_initializer_name(),
1009 vmSymbols::void_method_signature(),
1010 CHECK_NH);
1011 }
1012 Universe::set_system_thread_group(system_instance());
1013
1014 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1015 {
1016 JavaValue result(T_VOID);
1017 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1018 JavaCalls::call_special(&result,
1019 main_instance,
1020 klass,
1021 vmSymbols::object_initializer_name(),
1022 vmSymbols::threadgroup_string_void_signature(),
1023 system_instance,
1024 string,
1025 CHECK_NH);
1026 }
1027 return main_instance;
1028 }
1029
1030 // Creates the initial Thread
1031 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1032 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1033 instanceKlassHandle klass (THREAD, k);
1034 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1035
1036 java_lang_Thread::set_thread(thread_oop(), thread);
1037 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1038 thread->set_threadObj(thread_oop());
1039
1040 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1041
1042 JavaValue result(T_VOID);
1043 JavaCalls::call_special(&result, thread_oop,
1044 klass,
1045 vmSymbols::object_initializer_name(),
1046 vmSymbols::threadgroup_string_void_signature(),
1047 thread_group,
1048 string,
1049 CHECK_NULL);
1050 return thread_oop();
1051 }
1052
1053 static void call_initializeSystemClass(TRAPS) {
1054 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1055 instanceKlassHandle klass (THREAD, k);
1056
1057 JavaValue result(T_VOID);
1058 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1059 vmSymbols::void_method_signature(), CHECK);
1060 }
1061
1062 char java_runtime_name[128] = "";
1063 char java_runtime_version[128] = "";
1064
1065 // extract the JRE name from sun.misc.Version.java_runtime_name
1066 static const char* get_java_runtime_name(TRAPS) {
1067 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1068 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1069 fieldDescriptor fd;
1070 bool found = k != NULL &&
1071 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1072 vmSymbols::string_signature(), &fd);
1073 if (found) {
1074 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1075 if (name_oop == NULL)
1076 return NULL;
1077 const char* name = java_lang_String::as_utf8_string(name_oop,
1078 java_runtime_name,
1079 sizeof(java_runtime_name));
1080 return name;
1081 } else {
1082 return NULL;
1083 }
1084 }
1085
1086 // extract the JRE version from sun.misc.Version.java_runtime_version
1087 static const char* get_java_runtime_version(TRAPS) {
1088 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1089 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1090 fieldDescriptor fd;
1091 bool found = k != NULL &&
1092 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1093 vmSymbols::string_signature(), &fd);
1094 if (found) {
1095 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1096 if (name_oop == NULL)
1097 return NULL;
1098 const char* name = java_lang_String::as_utf8_string(name_oop,
1099 java_runtime_version,
1100 sizeof(java_runtime_version));
1101 return name;
1102 } else {
1103 return NULL;
1104 }
1105 }
1106
1107 // General purpose hook into Java code, run once when the VM is initialized.
1108 // The Java library method itself may be changed independently from the VM.
1109 static void call_postVMInitHook(TRAPS) {
1110 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1111 instanceKlassHandle klass (THREAD, k);
1112 if (klass.not_null()) {
1113 JavaValue result(T_VOID);
1114 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1115 vmSymbols::void_method_signature(),
1116 CHECK);
1117 }
1118 }
1119
1120 static void reset_vm_info_property(TRAPS) {
1121 // the vm info string
1122 ResourceMark rm(THREAD);
1123 const char *vm_info = VM_Version::vm_info_string();
1124
1125 // java.lang.System class
1126 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1127 instanceKlassHandle klass (THREAD, k);
1128
1129 // setProperty arguments
1130 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1131 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1132
1133 // return value
1134 JavaValue r(T_OBJECT);
1135
1136 // public static String setProperty(String key, String value);
1137 JavaCalls::call_static(&r,
1138 klass,
1139 vmSymbols::setProperty_name(),
1140 vmSymbols::string_string_string_signature(),
1141 key_str,
1142 value_str,
1143 CHECK);
1144 }
1145
1146
1147 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1148 assert(thread_group.not_null(), "thread group should be specified");
1149 assert(threadObj() == NULL, "should only create Java thread object once");
1150
1151 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1152 instanceKlassHandle klass (THREAD, k);
1153 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1154
1155 java_lang_Thread::set_thread(thread_oop(), this);
1156 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1157 set_threadObj(thread_oop());
1158
1159 JavaValue result(T_VOID);
1160 if (thread_name != NULL) {
1161 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1162 // Thread gets assigned specified name and null target
1163 JavaCalls::call_special(&result,
1164 thread_oop,
1165 klass,
1166 vmSymbols::object_initializer_name(),
1167 vmSymbols::threadgroup_string_void_signature(),
1168 thread_group, // Argument 1
1169 name, // Argument 2
1170 THREAD);
1171 } else {
1172 // Thread gets assigned name "Thread-nnn" and null target
1173 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1174 JavaCalls::call_special(&result,
1175 thread_oop,
1176 klass,
1177 vmSymbols::object_initializer_name(),
1178 vmSymbols::threadgroup_runnable_void_signature(),
1179 thread_group, // Argument 1
1180 Handle(), // Argument 2
1181 THREAD);
1182 }
1183
1184
1185 if (daemon) {
1186 java_lang_Thread::set_daemon(thread_oop());
1187 }
1188
1189 if (HAS_PENDING_EXCEPTION) {
1190 return;
1191 }
1192
1193 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1194 Handle threadObj(this, this->threadObj());
1195
1196 JavaCalls::call_special(&result,
1197 thread_group,
1198 group,
1199 vmSymbols::add_method_name(),
1200 vmSymbols::thread_void_signature(),
1201 threadObj, // Arg 1
1202 THREAD);
1203
1204
1205 }
1206
1207 // NamedThread -- non-JavaThread subclasses with multiple
1208 // uniquely named instances should derive from this.
1209 NamedThread::NamedThread() : Thread() {
1210 _name = NULL;
1211 _processed_thread = NULL;
1212 }
1213
1214 NamedThread::~NamedThread() {
1215 if (_name != NULL) {
1216 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1217 _name = NULL;
1218 }
1219 }
1220
1221 void NamedThread::set_name(const char* format, ...) {
1222 guarantee(_name == NULL, "Only get to set name once.");
1223 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1224 guarantee(_name != NULL, "alloc failure");
1225 va_list ap;
1226 va_start(ap, format);
1227 jio_vsnprintf(_name, max_name_len, format, ap);
1228 va_end(ap);
1229 }
1230
1231 // ======= WatcherThread ========
1232
1233 // The watcher thread exists to simulate timer interrupts. It should
1234 // be replaced by an abstraction over whatever native support for
1235 // timer interrupts exists on the platform.
1236
1237 WatcherThread* WatcherThread::_watcher_thread = NULL;
1238 bool WatcherThread::_startable = false;
1239 volatile bool WatcherThread::_should_terminate = false;
1240
1241 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1242 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1243 if (os::create_thread(this, os::watcher_thread)) {
1244 _watcher_thread = this;
1245
1246 // Set the watcher thread to the highest OS priority which should not be
1247 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1248 // is created. The only normal thread using this priority is the reference
1249 // handler thread, which runs for very short intervals only.
1250 // If the VMThread's priority is not lower than the WatcherThread profiling
1251 // will be inaccurate.
1252 os::set_priority(this, MaxPriority);
1253 if (!DisableStartThread) {
1254 os::start_thread(this);
1255 }
1256 }
1257 }
1258
1259 int WatcherThread::sleep() const {
1260 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1261
1262 // remaining will be zero if there are no tasks,
1263 // causing the WatcherThread to sleep until a task is
1264 // enrolled
1265 int remaining = PeriodicTask::time_to_wait();
1266 int time_slept = 0;
1267
1268 // we expect this to timeout - we only ever get unparked when
1269 // we should terminate or when a new task has been enrolled
1270 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1271
1272 jlong time_before_loop = os::javaTimeNanos();
1273
1274 for (;;) {
1275 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1276 jlong now = os::javaTimeNanos();
1277
1278 if (remaining == 0) {
1279 // if we didn't have any tasks we could have waited for a long time
1280 // consider the time_slept zero and reset time_before_loop
1281 time_slept = 0;
1282 time_before_loop = now;
1283 } else {
1284 // need to recalulate since we might have new tasks in _tasks
1285 time_slept = (int) ((now - time_before_loop) / 1000000);
1286 }
1287
1288 // Change to task list or spurious wakeup of some kind
1289 if (timedout || _should_terminate) {
1290 break;
1291 }
1292
1293 remaining = PeriodicTask::time_to_wait();
1294 if (remaining == 0) {
1295 // Last task was just disenrolled so loop around and wait until
1296 // another task gets enrolled
1297 continue;
1298 }
1299
1300 remaining -= time_slept;
1301 if (remaining <= 0)
1302 break;
1303 }
1304
1305 return time_slept;
1306 }
1307
1308 void WatcherThread::run() {
1309 assert(this == watcher_thread(), "just checking");
1310
1311 this->record_stack_base_and_size();
1312 this->initialize_thread_local_storage();
1313 this->set_active_handles(JNIHandleBlock::allocate_block());
1314 while(!_should_terminate) {
1315 assert(watcher_thread() == Thread::current(), "thread consistency check");
1316 assert(watcher_thread() == this, "thread consistency check");
1317
1318 // Calculate how long it'll be until the next PeriodicTask work
1319 // should be done, and sleep that amount of time.
1320 int time_waited = sleep();
1321
1322 if (is_error_reported()) {
1323 // A fatal error has happened, the error handler(VMError::report_and_die)
1324 // should abort JVM after creating an error log file. However in some
1325 // rare cases, the error handler itself might deadlock. Here we try to
1326 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1327 //
1328 // This code is in WatcherThread because WatcherThread wakes up
1329 // periodically so the fatal error handler doesn't need to do anything;
1330 // also because the WatcherThread is less likely to crash than other
1331 // threads.
1332
1333 for (;;) {
1334 if (!ShowMessageBoxOnError
1335 && (OnError == NULL || OnError[0] == '\0')
1336 && Arguments::abort_hook() == NULL) {
1337 os::sleep(this, 2 * 60 * 1000, false);
1338 fdStream err(defaultStream::output_fd());
1339 err.print_raw_cr("# [ timer expired, abort... ]");
1340 // skip atexit/vm_exit/vm_abort hooks
1341 os::die();
1342 }
1343
1344 // Wake up 5 seconds later, the fatal handler may reset OnError or
1345 // ShowMessageBoxOnError when it is ready to abort.
1346 os::sleep(this, 5 * 1000, false);
1347 }
1348 }
1349
1350 PeriodicTask::real_time_tick(time_waited);
1351 }
1352
1353 // Signal that it is terminated
1354 {
1355 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1356 _watcher_thread = NULL;
1357 Terminator_lock->notify();
1358 }
1359
1360 // Thread destructor usually does this..
1361 ThreadLocalStorage::set_thread(NULL);
1362 }
1363
1364 void WatcherThread::start() {
1365 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1366
1367 if (watcher_thread() == NULL && _startable) {
1368 _should_terminate = false;
1369 // Create the single instance of WatcherThread
1370 new WatcherThread();
1371 }
1372 }
1373
1374 void WatcherThread::make_startable() {
1375 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1376 _startable = true;
1377 }
1378
1379 void WatcherThread::stop() {
1380 {
1381 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1382 _should_terminate = true;
1383 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1384
1385 WatcherThread* watcher = watcher_thread();
1386 if (watcher != NULL)
1387 watcher->unpark();
1388 }
1389
1390 // it is ok to take late safepoints here, if needed
1391 MutexLocker mu(Terminator_lock);
1392
1393 while(watcher_thread() != NULL) {
1394 // This wait should make safepoint checks, wait without a timeout,
1395 // and wait as a suspend-equivalent condition.
1396 //
1397 // Note: If the FlatProfiler is running, then this thread is waiting
1398 // for the WatcherThread to terminate and the WatcherThread, via the
1399 // FlatProfiler task, is waiting for the external suspend request on
1400 // this thread to complete. wait_for_ext_suspend_completion() will
1401 // eventually timeout, but that takes time. Making this wait a
1402 // suspend-equivalent condition solves that timeout problem.
1403 //
1404 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1405 Mutex::_as_suspend_equivalent_flag);
1406 }
1407 }
1408
1409 void WatcherThread::unpark() {
1410 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1411 PeriodicTask_lock->notify();
1412 }
1413
1414 void WatcherThread::print_on(outputStream* st) const {
1415 st->print("\"%s\" ", name());
1416 Thread::print_on(st);
1417 st->cr();
1418 }
1419
1420 // ======= JavaThread ========
1421
1422 // A JavaThread is a normal Java thread
1423
1424 void JavaThread::initialize() {
1425 // Initialize fields
1426
1427 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1428 set_claimed_par_id(UINT_MAX);
1429
1430 set_saved_exception_pc(NULL);
1431 set_threadObj(NULL);
1432 _anchor.clear();
1433 set_entry_point(NULL);
1434 set_jni_functions(jni_functions());
1435 set_callee_target(NULL);
1436 set_vm_result(NULL);
1437 set_vm_result_2(NULL);
1438 set_vframe_array_head(NULL);
1439 set_vframe_array_last(NULL);
1440 set_deferred_locals(NULL);
1441 set_deopt_mark(NULL);
1442 set_deopt_nmethod(NULL);
1443 clear_must_deopt_id();
1444 set_monitor_chunks(NULL);
1445 set_next(NULL);
1446 set_thread_state(_thread_new);
1447 _terminated = _not_terminated;
1448 _privileged_stack_top = NULL;
1449 _array_for_gc = NULL;
1450 _suspend_equivalent = false;
1451 _in_deopt_handler = 0;
1452 _doing_unsafe_access = false;
1453 _stack_guard_state = stack_guard_unused;
1454 (void)const_cast<oop&>(_exception_oop = NULL);
1455 _exception_pc = 0;
1456 _exception_handler_pc = 0;
1457 _is_method_handle_return = 0;
1458 _jvmti_thread_state= NULL;
1459 _should_post_on_exceptions_flag = JNI_FALSE;
1460 _jvmti_get_loaded_classes_closure = NULL;
1461 _interp_only_mode = 0;
1462 _special_runtime_exit_condition = _no_async_condition;
1463 _pending_async_exception = NULL;
1464 _thread_stat = NULL;
1465 _thread_stat = new ThreadStatistics();
1466 _blocked_on_compilation = false;
1467 _jni_active_critical = 0;
1468 _pending_jni_exception_check_fn = NULL;
1469 _do_not_unlock_if_synchronized = false;
1470 _cached_monitor_info = NULL;
1471 _parker = Parker::Allocate(this) ;
1472
1473 #ifndef PRODUCT
1474 _jmp_ring_index = 0;
1475 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1476 record_jump(NULL, NULL, NULL, 0);
1477 }
1478 #endif /* PRODUCT */
1479
1480 set_thread_profiler(NULL);
1481 if (FlatProfiler::is_active()) {
1482 // This is where we would decide to either give each thread it's own profiler
1483 // or use one global one from FlatProfiler,
1484 // or up to some count of the number of profiled threads, etc.
1485 ThreadProfiler* pp = new ThreadProfiler();
1486 pp->engage();
1487 set_thread_profiler(pp);
1488 }
1489
1490 // Setup safepoint state info for this thread
1491 ThreadSafepointState::create(this);
1492
1493 debug_only(_java_call_counter = 0);
1494
1495 // JVMTI PopFrame support
1496 _popframe_condition = popframe_inactive;
1497 _popframe_preserved_args = NULL;
1498 _popframe_preserved_args_size = 0;
1499 _frames_to_pop_failed_realloc = 0;
1500
1501 pd_initialize();
1502 }
1503
1504 #if INCLUDE_ALL_GCS
1505 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1506 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1507 #endif // INCLUDE_ALL_GCS
1508
1509 JavaThread::JavaThread(bool is_attaching_via_jni) :
1510 Thread()
1511 #if INCLUDE_ALL_GCS
1512 , _satb_mark_queue(&_satb_mark_queue_set),
1513 _dirty_card_queue(&_dirty_card_queue_set)
1514 #endif // INCLUDE_ALL_GCS
1515 {
1516 initialize();
1517 if (is_attaching_via_jni) {
1518 _jni_attach_state = _attaching_via_jni;
1519 } else {
1520 _jni_attach_state = _not_attaching_via_jni;
1521 }
1522 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1523 }
1524
1525 bool JavaThread::reguard_stack(address cur_sp) {
1526 if (_stack_guard_state != stack_guard_yellow_disabled) {
1527 return true; // Stack already guarded or guard pages not needed.
1528 }
1529
1530 if (register_stack_overflow()) {
1531 // For those architectures which have separate register and
1532 // memory stacks, we must check the register stack to see if
1533 // it has overflowed.
1534 return false;
1535 }
1536
1537 // Java code never executes within the yellow zone: the latter is only
1538 // there to provoke an exception during stack banging. If java code
1539 // is executing there, either StackShadowPages should be larger, or
1540 // some exception code in c1, c2 or the interpreter isn't unwinding
1541 // when it should.
1542 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1543
1544 enable_stack_yellow_zone();
1545 return true;
1546 }
1547
1548 bool JavaThread::reguard_stack(void) {
1549 return reguard_stack(os::current_stack_pointer());
1550 }
1551
1552
1553 void JavaThread::block_if_vm_exited() {
1554 if (_terminated == _vm_exited) {
1555 // _vm_exited is set at safepoint, and Threads_lock is never released
1556 // we will block here forever
1557 Threads_lock->lock_without_safepoint_check();
1558 ShouldNotReachHere();
1559 }
1560 }
1561
1562
1563 // Remove this ifdef when C1 is ported to the compiler interface.
1564 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1565
1566 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1567 Thread()
1568 #if INCLUDE_ALL_GCS
1569 , _satb_mark_queue(&_satb_mark_queue_set),
1570 _dirty_card_queue(&_dirty_card_queue_set)
1571 #endif // INCLUDE_ALL_GCS
1572 {
1573 if (TraceThreadEvents) {
1574 tty->print_cr("creating thread %p", this);
1575 }
1576 initialize();
1577 _jni_attach_state = _not_attaching_via_jni;
1578 set_entry_point(entry_point);
1579 // Create the native thread itself.
1580 // %note runtime_23
1581 os::ThreadType thr_type = os::java_thread;
1582 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1583 os::java_thread;
1584 os::create_thread(this, thr_type, stack_sz);
1585 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1586 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1587 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1588 // the exception consists of creating the exception object & initializing it, initialization
1589 // will leave the VM via a JavaCall and then all locks must be unlocked).
1590 //
1591 // The thread is still suspended when we reach here. Thread must be explicit started
1592 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1593 // by calling Threads:add. The reason why this is not done here, is because the thread
1594 // object must be fully initialized (take a look at JVM_Start)
1595 }
1596
1597 JavaThread::~JavaThread() {
1598 if (TraceThreadEvents) {
1599 tty->print_cr("terminate thread %p", this);
1600 }
1601
1602 // JSR166 -- return the parker to the free list
1603 Parker::Release(_parker);
1604 _parker = NULL ;
1605
1606 // Free any remaining previous UnrollBlock
1607 vframeArray* old_array = vframe_array_last();
1608
1609 if (old_array != NULL) {
1610 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1611 old_array->set_unroll_block(NULL);
1612 delete old_info;
1613 delete old_array;
1614 }
1615
1616 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1617 if (deferred != NULL) {
1618 // This can only happen if thread is destroyed before deoptimization occurs.
1619 assert(deferred->length() != 0, "empty array!");
1620 do {
1621 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1622 deferred->remove_at(0);
1623 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1624 delete dlv;
1625 } while (deferred->length() != 0);
1626 delete deferred;
1627 }
1628
1629 // All Java related clean up happens in exit
1630 ThreadSafepointState::destroy(this);
1631 if (_thread_profiler != NULL) delete _thread_profiler;
1632 if (_thread_stat != NULL) delete _thread_stat;
1633 }
1634
1635
1636 // The first routine called by a new Java thread
1637 void JavaThread::run() {
1638 // initialize thread-local alloc buffer related fields
1639 this->initialize_tlab();
1640
1641 // used to test validitity of stack trace backs
1642 this->record_base_of_stack_pointer();
1643
1644 // Record real stack base and size.
1645 this->record_stack_base_and_size();
1646
1647 // Initialize thread local storage; set before calling MutexLocker
1648 this->initialize_thread_local_storage();
1649
1650 this->create_stack_guard_pages();
1651
1652 this->cache_global_variables();
1653
1654 // Thread is now sufficient initialized to be handled by the safepoint code as being
1655 // in the VM. Change thread state from _thread_new to _thread_in_vm
1656 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1657
1658 assert(JavaThread::current() == this, "sanity check");
1659 assert(!Thread::current()->owns_locks(), "sanity check");
1660
1661 DTRACE_THREAD_PROBE(start, this);
1662
1663 // This operation might block. We call that after all safepoint checks for a new thread has
1664 // been completed.
1665 this->set_active_handles(JNIHandleBlock::allocate_block());
1666
1667 if (JvmtiExport::should_post_thread_life()) {
1668 JvmtiExport::post_thread_start(this);
1669 }
1670
1671 EventThreadStart event;
1672 if (event.should_commit()) {
1673 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1674 event.commit();
1675 }
1676
1677 // We call another function to do the rest so we are sure that the stack addresses used
1678 // from there will be lower than the stack base just computed
1679 thread_main_inner();
1680
1681 // Note, thread is no longer valid at this point!
1682 }
1683
1684
1685 void JavaThread::thread_main_inner() {
1686 assert(JavaThread::current() == this, "sanity check");
1687 assert(this->threadObj() != NULL, "just checking");
1688
1689 // Execute thread entry point unless this thread has a pending exception
1690 // or has been stopped before starting.
1691 // Note: Due to JVM_StopThread we can have pending exceptions already!
1692 if (!this->has_pending_exception() &&
1693 !java_lang_Thread::is_stillborn(this->threadObj())) {
1694 {
1695 ResourceMark rm(this);
1696 this->set_native_thread_name(this->get_thread_name());
1697 }
1698 HandleMark hm(this);
1699 this->entry_point()(this, this);
1700 }
1701
1702 DTRACE_THREAD_PROBE(stop, this);
1703
1704 this->exit(false);
1705 delete this;
1706 }
1707
1708
1709 static void ensure_join(JavaThread* thread) {
1710 // We do not need to grap the Threads_lock, since we are operating on ourself.
1711 Handle threadObj(thread, thread->threadObj());
1712 assert(threadObj.not_null(), "java thread object must exist");
1713 ObjectLocker lock(threadObj, thread);
1714 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1715 thread->clear_pending_exception();
1716 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1717 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1718 // Clear the native thread instance - this makes isAlive return false and allows the join()
1719 // to complete once we've done the notify_all below
1720 java_lang_Thread::set_thread(threadObj(), NULL);
1721 lock.notify_all(thread);
1722 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1723 thread->clear_pending_exception();
1724 }
1725
1726
1727 // For any new cleanup additions, please check to see if they need to be applied to
1728 // cleanup_failed_attach_current_thread as well.
1729 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1730 assert(this == JavaThread::current(), "thread consistency check");
1731
1732 HandleMark hm(this);
1733 Handle uncaught_exception(this, this->pending_exception());
1734 this->clear_pending_exception();
1735 Handle threadObj(this, this->threadObj());
1736 assert(threadObj.not_null(), "Java thread object should be created");
1737
1738 if (get_thread_profiler() != NULL) {
1739 get_thread_profiler()->disengage();
1740 ResourceMark rm;
1741 get_thread_profiler()->print(get_thread_name());
1742 }
1743
1744
1745 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1746 {
1747 EXCEPTION_MARK;
1748
1749 CLEAR_PENDING_EXCEPTION;
1750 }
1751 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1752 // has to be fixed by a runtime query method
1753 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1754 // JSR-166: change call from from ThreadGroup.uncaughtException to
1755 // java.lang.Thread.dispatchUncaughtException
1756 if (uncaught_exception.not_null()) {
1757 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1758 {
1759 EXCEPTION_MARK;
1760 // Check if the method Thread.dispatchUncaughtException() exists. If so
1761 // call it. Otherwise we have an older library without the JSR-166 changes,
1762 // so call ThreadGroup.uncaughtException()
1763 KlassHandle recvrKlass(THREAD, threadObj->klass());
1764 CallInfo callinfo;
1765 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1766 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1767 vmSymbols::dispatchUncaughtException_name(),
1768 vmSymbols::throwable_void_signature(),
1769 KlassHandle(), false, false, THREAD);
1770 CLEAR_PENDING_EXCEPTION;
1771 methodHandle method = callinfo.selected_method();
1772 if (method.not_null()) {
1773 JavaValue result(T_VOID);
1774 JavaCalls::call_virtual(&result,
1775 threadObj, thread_klass,
1776 vmSymbols::dispatchUncaughtException_name(),
1777 vmSymbols::throwable_void_signature(),
1778 uncaught_exception,
1779 THREAD);
1780 } else {
1781 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1782 JavaValue result(T_VOID);
1783 JavaCalls::call_virtual(&result,
1784 group, thread_group,
1785 vmSymbols::uncaughtException_name(),
1786 vmSymbols::thread_throwable_void_signature(),
1787 threadObj, // Arg 1
1788 uncaught_exception, // Arg 2
1789 THREAD);
1790 }
1791 if (HAS_PENDING_EXCEPTION) {
1792 ResourceMark rm(this);
1793 jio_fprintf(defaultStream::error_stream(),
1794 "\nException: %s thrown from the UncaughtExceptionHandler"
1795 " in thread \"%s\"\n",
1796 pending_exception()->klass()->external_name(),
1797 get_thread_name());
1798 CLEAR_PENDING_EXCEPTION;
1799 }
1800 }
1801 }
1802
1803 // Called before the java thread exit since we want to read info
1804 // from java_lang_Thread object
1805 EventThreadEnd event;
1806 if (event.should_commit()) {
1807 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1808 event.commit();
1809 }
1810
1811 // Call after last event on thread
1812 EVENT_THREAD_EXIT(this);
1813
1814 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1815 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1816 // is deprecated anyhow.
1817 if (!is_Compiler_thread()) {
1818 int count = 3;
1819 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1820 EXCEPTION_MARK;
1821 JavaValue result(T_VOID);
1822 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1823 JavaCalls::call_virtual(&result,
1824 threadObj, thread_klass,
1825 vmSymbols::exit_method_name(),
1826 vmSymbols::void_method_signature(),
1827 THREAD);
1828 CLEAR_PENDING_EXCEPTION;
1829 }
1830 }
1831 // notify JVMTI
1832 if (JvmtiExport::should_post_thread_life()) {
1833 JvmtiExport::post_thread_end(this);
1834 }
1835
1836 // We have notified the agents that we are exiting, before we go on,
1837 // we must check for a pending external suspend request and honor it
1838 // in order to not surprise the thread that made the suspend request.
1839 while (true) {
1840 {
1841 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1842 if (!is_external_suspend()) {
1843 set_terminated(_thread_exiting);
1844 ThreadService::current_thread_exiting(this);
1845 break;
1846 }
1847 // Implied else:
1848 // Things get a little tricky here. We have a pending external
1849 // suspend request, but we are holding the SR_lock so we
1850 // can't just self-suspend. So we temporarily drop the lock
1851 // and then self-suspend.
1852 }
1853
1854 ThreadBlockInVM tbivm(this);
1855 java_suspend_self();
1856
1857 // We're done with this suspend request, but we have to loop around
1858 // and check again. Eventually we will get SR_lock without a pending
1859 // external suspend request and will be able to mark ourselves as
1860 // exiting.
1861 }
1862 // no more external suspends are allowed at this point
1863 } else {
1864 // before_exit() has already posted JVMTI THREAD_END events
1865 }
1866
1867 // Notify waiters on thread object. This has to be done after exit() is called
1868 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1869 // group should have the destroyed bit set before waiters are notified).
1870 ensure_join(this);
1871 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1872
1873 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1874 // held by this thread must be released. A detach operation must only
1875 // get here if there are no Java frames on the stack. Therefore, any
1876 // owned monitors at this point MUST be JNI-acquired monitors which are
1877 // pre-inflated and in the monitor cache.
1878 //
1879 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1880 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1881 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1882 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1883 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1884 }
1885
1886 // These things needs to be done while we are still a Java Thread. Make sure that thread
1887 // is in a consistent state, in case GC happens
1888 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1889
1890 if (active_handles() != NULL) {
1891 JNIHandleBlock* block = active_handles();
1892 set_active_handles(NULL);
1893 JNIHandleBlock::release_block(block);
1894 }
1895
1896 if (free_handle_block() != NULL) {
1897 JNIHandleBlock* block = free_handle_block();
1898 set_free_handle_block(NULL);
1899 JNIHandleBlock::release_block(block);
1900 }
1901
1902 // These have to be removed while this is still a valid thread.
1903 remove_stack_guard_pages();
1904
1905 if (UseTLAB) {
1906 tlab().make_parsable(true); // retire TLAB
1907 }
1908
1909 if (JvmtiEnv::environments_might_exist()) {
1910 JvmtiExport::cleanup_thread(this);
1911 }
1912
1913 // We must flush any deferred card marks before removing a thread from
1914 // the list of active threads.
1915 Universe::heap()->flush_deferred_store_barrier(this);
1916 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1917
1918 #if INCLUDE_ALL_GCS
1919 // We must flush the G1-related buffers before removing a thread
1920 // from the list of active threads. We must do this after any deferred
1921 // card marks have been flushed (above) so that any entries that are
1922 // added to the thread's dirty card queue as a result are not lost.
1923 if (UseG1GC) {
1924 flush_barrier_queues();
1925 }
1926 #endif // INCLUDE_ALL_GCS
1927
1928 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1929 Threads::remove(this);
1930 }
1931
1932 #if INCLUDE_ALL_GCS
1933 // Flush G1-related queues.
1934 void JavaThread::flush_barrier_queues() {
1935 satb_mark_queue().flush();
1936 dirty_card_queue().flush();
1937 }
1938
1939 void JavaThread::initialize_queues() {
1940 assert(!SafepointSynchronize::is_at_safepoint(),
1941 "we should not be at a safepoint");
1942
1943 ObjPtrQueue& satb_queue = satb_mark_queue();
1944 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1945 // The SATB queue should have been constructed with its active
1946 // field set to false.
1947 assert(!satb_queue.is_active(), "SATB queue should not be active");
1948 assert(satb_queue.is_empty(), "SATB queue should be empty");
1949 // If we are creating the thread during a marking cycle, we should
1950 // set the active field of the SATB queue to true.
1951 if (satb_queue_set.is_active()) {
1952 satb_queue.set_active(true);
1953 }
1954
1955 DirtyCardQueue& dirty_queue = dirty_card_queue();
1956 // The dirty card queue should have been constructed with its
1957 // active field set to true.
1958 assert(dirty_queue.is_active(), "dirty card queue should be active");
1959 }
1960 #endif // INCLUDE_ALL_GCS
1961
1962 void JavaThread::cleanup_failed_attach_current_thread() {
1963 if (get_thread_profiler() != NULL) {
1964 get_thread_profiler()->disengage();
1965 ResourceMark rm;
1966 get_thread_profiler()->print(get_thread_name());
1967 }
1968
1969 if (active_handles() != NULL) {
1970 JNIHandleBlock* block = active_handles();
1971 set_active_handles(NULL);
1972 JNIHandleBlock::release_block(block);
1973 }
1974
1975 if (free_handle_block() != NULL) {
1976 JNIHandleBlock* block = free_handle_block();
1977 set_free_handle_block(NULL);
1978 JNIHandleBlock::release_block(block);
1979 }
1980
1981 // These have to be removed while this is still a valid thread.
1982 remove_stack_guard_pages();
1983
1984 if (UseTLAB) {
1985 tlab().make_parsable(true); // retire TLAB, if any
1986 }
1987
1988 #if INCLUDE_ALL_GCS
1989 if (UseG1GC) {
1990 flush_barrier_queues();
1991 }
1992 #endif // INCLUDE_ALL_GCS
1993
1994 Threads::remove(this);
1995 delete this;
1996 }
1997
1998
1999
2000
2001 JavaThread* JavaThread::active() {
2002 Thread* thread = ThreadLocalStorage::thread();
2003 assert(thread != NULL, "just checking");
2004 if (thread->is_Java_thread()) {
2005 return (JavaThread*) thread;
2006 } else {
2007 assert(thread->is_VM_thread(), "this must be a vm thread");
2008 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2009 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2010 assert(ret->is_Java_thread(), "must be a Java thread");
2011 return ret;
2012 }
2013 }
2014
2015 bool JavaThread::is_lock_owned(address adr) const {
2016 if (Thread::is_lock_owned(adr)) return true;
2017
2018 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2019 if (chunk->contains(adr)) return true;
2020 }
2021
2022 return false;
2023 }
2024
2025
2026 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2027 chunk->set_next(monitor_chunks());
2028 set_monitor_chunks(chunk);
2029 }
2030
2031 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2032 guarantee(monitor_chunks() != NULL, "must be non empty");
2033 if (monitor_chunks() == chunk) {
2034 set_monitor_chunks(chunk->next());
2035 } else {
2036 MonitorChunk* prev = monitor_chunks();
2037 while (prev->next() != chunk) prev = prev->next();
2038 prev->set_next(chunk->next());
2039 }
2040 }
2041
2042 // JVM support.
2043
2044 // Note: this function shouldn't block if it's called in
2045 // _thread_in_native_trans state (such as from
2046 // check_special_condition_for_native_trans()).
2047 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2048
2049 if (has_last_Java_frame() && has_async_condition()) {
2050 // If we are at a polling page safepoint (not a poll return)
2051 // then we must defer async exception because live registers
2052 // will be clobbered by the exception path. Poll return is
2053 // ok because the call we a returning from already collides
2054 // with exception handling registers and so there is no issue.
2055 // (The exception handling path kills call result registers but
2056 // this is ok since the exception kills the result anyway).
2057
2058 if (is_at_poll_safepoint()) {
2059 // if the code we are returning to has deoptimized we must defer
2060 // the exception otherwise live registers get clobbered on the
2061 // exception path before deoptimization is able to retrieve them.
2062 //
2063 RegisterMap map(this, false);
2064 frame caller_fr = last_frame().sender(&map);
2065 assert(caller_fr.is_compiled_frame(), "what?");
2066 if (caller_fr.is_deoptimized_frame()) {
2067 if (TraceExceptions) {
2068 ResourceMark rm;
2069 tty->print_cr("deferred async exception at compiled safepoint");
2070 }
2071 return;
2072 }
2073 }
2074 }
2075
2076 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2077 if (condition == _no_async_condition) {
2078 // Conditions have changed since has_special_runtime_exit_condition()
2079 // was called:
2080 // - if we were here only because of an external suspend request,
2081 // then that was taken care of above (or cancelled) so we are done
2082 // - if we were here because of another async request, then it has
2083 // been cleared between the has_special_runtime_exit_condition()
2084 // and now so again we are done
2085 return;
2086 }
2087
2088 // Check for pending async. exception
2089 if (_pending_async_exception != NULL) {
2090 // Only overwrite an already pending exception, if it is not a threadDeath.
2091 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2092
2093 // We cannot call Exceptions::_throw(...) here because we cannot block
2094 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2095
2096 if (TraceExceptions) {
2097 ResourceMark rm;
2098 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2099 if (has_last_Java_frame() ) {
2100 frame f = last_frame();
2101 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2102 }
2103 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2104 }
2105 _pending_async_exception = NULL;
2106 clear_has_async_exception();
2107 }
2108 }
2109
2110 if (check_unsafe_error &&
2111 condition == _async_unsafe_access_error && !has_pending_exception()) {
2112 condition = _no_async_condition; // done
2113 switch (thread_state()) {
2114 case _thread_in_vm:
2115 {
2116 JavaThread* THREAD = this;
2117 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2118 }
2119 case _thread_in_native:
2120 {
2121 ThreadInVMfromNative tiv(this);
2122 JavaThread* THREAD = this;
2123 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2124 }
2125 case _thread_in_Java:
2126 {
2127 ThreadInVMfromJava tiv(this);
2128 JavaThread* THREAD = this;
2129 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2130 }
2131 default:
2132 ShouldNotReachHere();
2133 }
2134 }
2135
2136 assert(condition == _no_async_condition || has_pending_exception() ||
2137 (!check_unsafe_error && condition == _async_unsafe_access_error),
2138 "must have handled the async condition, if no exception");
2139 }
2140
2141 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2142 //
2143 // Check for pending external suspend. Internal suspend requests do
2144 // not use handle_special_runtime_exit_condition().
2145 // If JNIEnv proxies are allowed, don't self-suspend if the target
2146 // thread is not the current thread. In older versions of jdbx, jdbx
2147 // threads could call into the VM with another thread's JNIEnv so we
2148 // can be here operating on behalf of a suspended thread (4432884).
2149 bool do_self_suspend = is_external_suspend_with_lock();
2150 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2151 //
2152 // Because thread is external suspended the safepoint code will count
2153 // thread as at a safepoint. This can be odd because we can be here
2154 // as _thread_in_Java which would normally transition to _thread_blocked
2155 // at a safepoint. We would like to mark the thread as _thread_blocked
2156 // before calling java_suspend_self like all other callers of it but
2157 // we must then observe proper safepoint protocol. (We can't leave
2158 // _thread_blocked with a safepoint in progress). However we can be
2159 // here as _thread_in_native_trans so we can't use a normal transition
2160 // constructor/destructor pair because they assert on that type of
2161 // transition. We could do something like:
2162 //
2163 // JavaThreadState state = thread_state();
2164 // set_thread_state(_thread_in_vm);
2165 // {
2166 // ThreadBlockInVM tbivm(this);
2167 // java_suspend_self()
2168 // }
2169 // set_thread_state(_thread_in_vm_trans);
2170 // if (safepoint) block;
2171 // set_thread_state(state);
2172 //
2173 // but that is pretty messy. Instead we just go with the way the
2174 // code has worked before and note that this is the only path to
2175 // java_suspend_self that doesn't put the thread in _thread_blocked
2176 // mode.
2177
2178 frame_anchor()->make_walkable(this);
2179 java_suspend_self();
2180
2181 // We might be here for reasons in addition to the self-suspend request
2182 // so check for other async requests.
2183 }
2184
2185 if (check_asyncs) {
2186 check_and_handle_async_exceptions();
2187 }
2188 }
2189
2190 void JavaThread::send_thread_stop(oop java_throwable) {
2191 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2192 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2193 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2194
2195 // Do not throw asynchronous exceptions against the compiler thread
2196 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2197 if (is_Compiler_thread()) return;
2198
2199 {
2200 // Actually throw the Throwable against the target Thread - however
2201 // only if there is no thread death exception installed already.
2202 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2203 // If the topmost frame is a runtime stub, then we are calling into
2204 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2205 // must deoptimize the caller before continuing, as the compiled exception handler table
2206 // may not be valid
2207 if (has_last_Java_frame()) {
2208 frame f = last_frame();
2209 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2210 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2211 RegisterMap reg_map(this, UseBiasedLocking);
2212 frame compiled_frame = f.sender(®_map);
2213 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2214 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2215 }
2216 }
2217 }
2218
2219 // Set async. pending exception in thread.
2220 set_pending_async_exception(java_throwable);
2221
2222 if (TraceExceptions) {
2223 ResourceMark rm;
2224 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2225 }
2226 // for AbortVMOnException flag
2227 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2228 }
2229 }
2230
2231
2232 // Interrupt thread so it will wake up from a potential wait()
2233 Thread::interrupt(this);
2234 }
2235
2236 // External suspension mechanism.
2237 //
2238 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2239 // to any VM_locks and it is at a transition
2240 // Self-suspension will happen on the transition out of the vm.
2241 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2242 //
2243 // Guarantees on return:
2244 // + Target thread will not execute any new bytecode (that's why we need to
2245 // force a safepoint)
2246 // + Target thread will not enter any new monitors
2247 //
2248 void JavaThread::java_suspend() {
2249 { MutexLocker mu(Threads_lock);
2250 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2251 return;
2252 }
2253 }
2254
2255 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2256 if (!is_external_suspend()) {
2257 // a racing resume has cancelled us; bail out now
2258 return;
2259 }
2260
2261 // suspend is done
2262 uint32_t debug_bits = 0;
2263 // Warning: is_ext_suspend_completed() may temporarily drop the
2264 // SR_lock to allow the thread to reach a stable thread state if
2265 // it is currently in a transient thread state.
2266 if (is_ext_suspend_completed(false /* !called_by_wait */,
2267 SuspendRetryDelay, &debug_bits) ) {
2268 return;
2269 }
2270 }
2271
2272 VM_ForceSafepoint vm_suspend;
2273 VMThread::execute(&vm_suspend);
2274 }
2275
2276 // Part II of external suspension.
2277 // A JavaThread self suspends when it detects a pending external suspend
2278 // request. This is usually on transitions. It is also done in places
2279 // where continuing to the next transition would surprise the caller,
2280 // e.g., monitor entry.
2281 //
2282 // Returns the number of times that the thread self-suspended.
2283 //
2284 // Note: DO NOT call java_suspend_self() when you just want to block current
2285 // thread. java_suspend_self() is the second stage of cooperative
2286 // suspension for external suspend requests and should only be used
2287 // to complete an external suspend request.
2288 //
2289 int JavaThread::java_suspend_self() {
2290 int ret = 0;
2291
2292 // we are in the process of exiting so don't suspend
2293 if (is_exiting()) {
2294 clear_external_suspend();
2295 return ret;
2296 }
2297
2298 assert(_anchor.walkable() ||
2299 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2300 "must have walkable stack");
2301
2302 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2303
2304 assert(!this->is_ext_suspended(),
2305 "a thread trying to self-suspend should not already be suspended");
2306
2307 if (this->is_suspend_equivalent()) {
2308 // If we are self-suspending as a result of the lifting of a
2309 // suspend equivalent condition, then the suspend_equivalent
2310 // flag is not cleared until we set the ext_suspended flag so
2311 // that wait_for_ext_suspend_completion() returns consistent
2312 // results.
2313 this->clear_suspend_equivalent();
2314 }
2315
2316 // A racing resume may have cancelled us before we grabbed SR_lock
2317 // above. Or another external suspend request could be waiting for us
2318 // by the time we return from SR_lock()->wait(). The thread
2319 // that requested the suspension may already be trying to walk our
2320 // stack and if we return now, we can change the stack out from under
2321 // it. This would be a "bad thing (TM)" and cause the stack walker
2322 // to crash. We stay self-suspended until there are no more pending
2323 // external suspend requests.
2324 while (is_external_suspend()) {
2325 ret++;
2326 this->set_ext_suspended();
2327
2328 // _ext_suspended flag is cleared by java_resume()
2329 while (is_ext_suspended()) {
2330 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2331 }
2332 }
2333
2334 return ret;
2335 }
2336
2337 #ifdef ASSERT
2338 // verify the JavaThread has not yet been published in the Threads::list, and
2339 // hence doesn't need protection from concurrent access at this stage
2340 void JavaThread::verify_not_published() {
2341 if (!Threads_lock->owned_by_self()) {
2342 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2343 assert( !Threads::includes(this),
2344 "java thread shouldn't have been published yet!");
2345 }
2346 else {
2347 assert( !Threads::includes(this),
2348 "java thread shouldn't have been published yet!");
2349 }
2350 }
2351 #endif
2352
2353 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2354 // progress or when _suspend_flags is non-zero.
2355 // Current thread needs to self-suspend if there is a suspend request and/or
2356 // block if a safepoint is in progress.
2357 // Async exception ISN'T checked.
2358 // Note only the ThreadInVMfromNative transition can call this function
2359 // directly and when thread state is _thread_in_native_trans
2360 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2361 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2362
2363 JavaThread *curJT = JavaThread::current();
2364 bool do_self_suspend = thread->is_external_suspend();
2365
2366 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2367
2368 // If JNIEnv proxies are allowed, don't self-suspend if the target
2369 // thread is not the current thread. In older versions of jdbx, jdbx
2370 // threads could call into the VM with another thread's JNIEnv so we
2371 // can be here operating on behalf of a suspended thread (4432884).
2372 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2373 JavaThreadState state = thread->thread_state();
2374
2375 // We mark this thread_blocked state as a suspend-equivalent so
2376 // that a caller to is_ext_suspend_completed() won't be confused.
2377 // The suspend-equivalent state is cleared by java_suspend_self().
2378 thread->set_suspend_equivalent();
2379
2380 // If the safepoint code sees the _thread_in_native_trans state, it will
2381 // wait until the thread changes to other thread state. There is no
2382 // guarantee on how soon we can obtain the SR_lock and complete the
2383 // self-suspend request. It would be a bad idea to let safepoint wait for
2384 // too long. Temporarily change the state to _thread_blocked to
2385 // let the VM thread know that this thread is ready for GC. The problem
2386 // of changing thread state is that safepoint could happen just after
2387 // java_suspend_self() returns after being resumed, and VM thread will
2388 // see the _thread_blocked state. We must check for safepoint
2389 // after restoring the state and make sure we won't leave while a safepoint
2390 // is in progress.
2391 thread->set_thread_state(_thread_blocked);
2392 thread->java_suspend_self();
2393 thread->set_thread_state(state);
2394 // Make sure new state is seen by VM thread
2395 if (os::is_MP()) {
2396 if (UseMembar) {
2397 // Force a fence between the write above and read below
2398 OrderAccess::fence();
2399 } else {
2400 // Must use this rather than serialization page in particular on Windows
2401 InterfaceSupport::serialize_memory(thread);
2402 }
2403 }
2404 }
2405
2406 if (SafepointSynchronize::do_call_back()) {
2407 // If we are safepointing, then block the caller which may not be
2408 // the same as the target thread (see above).
2409 SafepointSynchronize::block(curJT);
2410 }
2411
2412 if (thread->is_deopt_suspend()) {
2413 thread->clear_deopt_suspend();
2414 RegisterMap map(thread, false);
2415 frame f = thread->last_frame();
2416 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2417 f = f.sender(&map);
2418 }
2419 if (f.id() == thread->must_deopt_id()) {
2420 thread->clear_must_deopt_id();
2421 f.deoptimize(thread);
2422 } else {
2423 fatal("missed deoptimization!");
2424 }
2425 }
2426 }
2427
2428 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2429 // progress or when _suspend_flags is non-zero.
2430 // Current thread needs to self-suspend if there is a suspend request and/or
2431 // block if a safepoint is in progress.
2432 // Also check for pending async exception (not including unsafe access error).
2433 // Note only the native==>VM/Java barriers can call this function and when
2434 // thread state is _thread_in_native_trans.
2435 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2436 check_safepoint_and_suspend_for_native_trans(thread);
2437
2438 if (thread->has_async_exception()) {
2439 // We are in _thread_in_native_trans state, don't handle unsafe
2440 // access error since that may block.
2441 thread->check_and_handle_async_exceptions(false);
2442 }
2443 }
2444
2445 // This is a variant of the normal
2446 // check_special_condition_for_native_trans with slightly different
2447 // semantics for use by critical native wrappers. It does all the
2448 // normal checks but also performs the transition back into
2449 // thread_in_Java state. This is required so that critical natives
2450 // can potentially block and perform a GC if they are the last thread
2451 // exiting the GC_locker.
2452 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2453 check_special_condition_for_native_trans(thread);
2454
2455 // Finish the transition
2456 thread->set_thread_state(_thread_in_Java);
2457
2458 if (thread->do_critical_native_unlock()) {
2459 ThreadInVMfromJavaNoAsyncException tiv(thread);
2460 GC_locker::unlock_critical(thread);
2461 thread->clear_critical_native_unlock();
2462 }
2463 }
2464
2465 // We need to guarantee the Threads_lock here, since resumes are not
2466 // allowed during safepoint synchronization
2467 // Can only resume from an external suspension
2468 void JavaThread::java_resume() {
2469 assert_locked_or_safepoint(Threads_lock);
2470
2471 // Sanity check: thread is gone, has started exiting or the thread
2472 // was not externally suspended.
2473 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2474 return;
2475 }
2476
2477 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2478
2479 clear_external_suspend();
2480
2481 if (is_ext_suspended()) {
2482 clear_ext_suspended();
2483 SR_lock()->notify_all();
2484 }
2485 }
2486
2487 void JavaThread::create_stack_guard_pages() {
2488 if (!os::uses_stack_guard_pages() ||
2489 _stack_guard_state != stack_guard_unused ||
2490 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2491 if (TraceThreadEvents) {
2492 tty->print_cr("Stack guard page creation for thread "
2493 UINTX_FORMAT " disabled", os::current_thread_id());
2494 }
2495 return;
2496 }
2497 address low_addr = stack_base() - stack_size();
2498 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2499
2500 int allocate = os::allocate_stack_guard_pages();
2501 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2502
2503 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2504 warning("Attempt to allocate stack guard pages failed.");
2505 return;
2506 }
2507
2508 if (os::guard_memory((char *) low_addr, len)) {
2509 _stack_guard_state = stack_guard_enabled;
2510 } else {
2511 warning("Attempt to protect stack guard pages failed.");
2512 if (os::uncommit_memory((char *) low_addr, len)) {
2513 warning("Attempt to deallocate stack guard pages failed.");
2514 }
2515 }
2516 }
2517
2518 void JavaThread::remove_stack_guard_pages() {
2519 assert(Thread::current() == this, "from different thread");
2520 if (_stack_guard_state == stack_guard_unused) return;
2521 address low_addr = stack_base() - stack_size();
2522 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2523
2524 if (os::allocate_stack_guard_pages()) {
2525 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2526 _stack_guard_state = stack_guard_unused;
2527 } else {
2528 warning("Attempt to deallocate stack guard pages failed.");
2529 }
2530 } else {
2531 if (_stack_guard_state == stack_guard_unused) return;
2532 if (os::unguard_memory((char *) low_addr, len)) {
2533 _stack_guard_state = stack_guard_unused;
2534 } else {
2535 warning("Attempt to unprotect stack guard pages failed.");
2536 }
2537 }
2538 }
2539
2540 void JavaThread::enable_stack_yellow_zone() {
2541 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2542 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2543
2544 // The base notation is from the stacks point of view, growing downward.
2545 // We need to adjust it to work correctly with guard_memory()
2546 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2547
2548 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2549 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2550
2551 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2552 _stack_guard_state = stack_guard_enabled;
2553 } else {
2554 warning("Attempt to guard stack yellow zone failed.");
2555 }
2556 enable_register_stack_guard();
2557 }
2558
2559 void JavaThread::disable_stack_yellow_zone() {
2560 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2561 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2562
2563 // Simply return if called for a thread that does not use guard pages.
2564 if (_stack_guard_state == stack_guard_unused) return;
2565
2566 // The base notation is from the stacks point of view, growing downward.
2567 // We need to adjust it to work correctly with guard_memory()
2568 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2569
2570 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2571 _stack_guard_state = stack_guard_yellow_disabled;
2572 } else {
2573 warning("Attempt to unguard stack yellow zone failed.");
2574 }
2575 disable_register_stack_guard();
2576 }
2577
2578 void JavaThread::enable_stack_red_zone() {
2579 // The base notation is from the stacks point of view, growing downward.
2580 // We need to adjust it to work correctly with guard_memory()
2581 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2582 address base = stack_red_zone_base() - stack_red_zone_size();
2583
2584 guarantee(base < stack_base(),"Error calculating stack red zone");
2585 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2586
2587 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2588 warning("Attempt to guard stack red zone failed.");
2589 }
2590 }
2591
2592 void JavaThread::disable_stack_red_zone() {
2593 // The base notation is from the stacks point of view, growing downward.
2594 // We need to adjust it to work correctly with guard_memory()
2595 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2596 address base = stack_red_zone_base() - stack_red_zone_size();
2597 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2598 warning("Attempt to unguard stack red zone failed.");
2599 }
2600 }
2601
2602 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2603 // ignore is there is no stack
2604 if (!has_last_Java_frame()) return;
2605 // traverse the stack frames. Starts from top frame.
2606 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2607 frame* fr = fst.current();
2608 f(fr, fst.register_map());
2609 }
2610 }
2611
2612
2613 #ifndef PRODUCT
2614 // Deoptimization
2615 // Function for testing deoptimization
2616 void JavaThread::deoptimize() {
2617 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2618 StackFrameStream fst(this, UseBiasedLocking);
2619 bool deopt = false; // Dump stack only if a deopt actually happens.
2620 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2621 // Iterate over all frames in the thread and deoptimize
2622 for(; !fst.is_done(); fst.next()) {
2623 if(fst.current()->can_be_deoptimized()) {
2624
2625 if (only_at) {
2626 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2627 // consists of comma or carriage return separated numbers so
2628 // search for the current bci in that string.
2629 address pc = fst.current()->pc();
2630 nmethod* nm = (nmethod*) fst.current()->cb();
2631 ScopeDesc* sd = nm->scope_desc_at( pc);
2632 char buffer[8];
2633 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2634 size_t len = strlen(buffer);
2635 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2636 while (found != NULL) {
2637 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2638 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2639 // Check that the bci found is bracketed by terminators.
2640 break;
2641 }
2642 found = strstr(found + 1, buffer);
2643 }
2644 if (!found) {
2645 continue;
2646 }
2647 }
2648
2649 if (DebugDeoptimization && !deopt) {
2650 deopt = true; // One-time only print before deopt
2651 tty->print_cr("[BEFORE Deoptimization]");
2652 trace_frames();
2653 trace_stack();
2654 }
2655 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2656 }
2657 }
2658
2659 if (DebugDeoptimization && deopt) {
2660 tty->print_cr("[AFTER Deoptimization]");
2661 trace_frames();
2662 }
2663 }
2664
2665
2666 // Make zombies
2667 void JavaThread::make_zombies() {
2668 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2669 if (fst.current()->can_be_deoptimized()) {
2670 // it is a Java nmethod
2671 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2672 nm->make_not_entrant();
2673 }
2674 }
2675 }
2676 #endif // PRODUCT
2677
2678
2679 void JavaThread::deoptimized_wrt_marked_nmethods() {
2680 if (!has_last_Java_frame()) return;
2681 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2682 StackFrameStream fst(this, UseBiasedLocking);
2683 for(; !fst.is_done(); fst.next()) {
2684 if (fst.current()->should_be_deoptimized()) {
2685 if (LogCompilation && xtty != NULL) {
2686 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2687 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2688 this->name(), nm != NULL ? nm->compile_id() : -1);
2689 }
2690
2691 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2692 }
2693 }
2694 }
2695
2696
2697 // GC support
2698 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2699
2700 void JavaThread::gc_epilogue() {
2701 frames_do(frame_gc_epilogue);
2702 }
2703
2704
2705 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2706
2707 void JavaThread::gc_prologue() {
2708 frames_do(frame_gc_prologue);
2709 }
2710
2711 // If the caller is a NamedThread, then remember, in the current scope,
2712 // the given JavaThread in its _processed_thread field.
2713 class RememberProcessedThread: public StackObj {
2714 NamedThread* _cur_thr;
2715 public:
2716 RememberProcessedThread(JavaThread* jthr) {
2717 Thread* thread = Thread::current();
2718 if (thread->is_Named_thread()) {
2719 _cur_thr = (NamedThread *)thread;
2720 _cur_thr->set_processed_thread(jthr);
2721 } else {
2722 _cur_thr = NULL;
2723 }
2724 }
2725
2726 ~RememberProcessedThread() {
2727 if (_cur_thr) {
2728 _cur_thr->set_processed_thread(NULL);
2729 }
2730 }
2731 };
2732
2733 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2734 // Verify that the deferred card marks have been flushed.
2735 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2736
2737 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2738 // since there may be more than one thread using each ThreadProfiler.
2739
2740 // Traverse the GCHandles
2741 Thread::oops_do(f, cld_f, cf);
2742
2743 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2744 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2745
2746 if (has_last_Java_frame()) {
2747 // Record JavaThread to GC thread
2748 RememberProcessedThread rpt(this);
2749
2750 // Traverse the privileged stack
2751 if (_privileged_stack_top != NULL) {
2752 _privileged_stack_top->oops_do(f);
2753 }
2754
2755 // traverse the registered growable array
2756 if (_array_for_gc != NULL) {
2757 for (int index = 0; index < _array_for_gc->length(); index++) {
2758 f->do_oop(_array_for_gc->adr_at(index));
2759 }
2760 }
2761
2762 // Traverse the monitor chunks
2763 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2764 chunk->oops_do(f);
2765 }
2766
2767 // Traverse the execution stack
2768 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2769 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2770 }
2771 }
2772
2773 // callee_target is never live across a gc point so NULL it here should
2774 // it still contain a methdOop.
2775
2776 set_callee_target(NULL);
2777
2778 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2779 // If we have deferred set_locals there might be oops waiting to be
2780 // written
2781 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2782 if (list != NULL) {
2783 for (int i = 0; i < list->length(); i++) {
2784 list->at(i)->oops_do(f);
2785 }
2786 }
2787
2788 // Traverse instance variables at the end since the GC may be moving things
2789 // around using this function
2790 f->do_oop((oop*) &_threadObj);
2791 f->do_oop((oop*) &_vm_result);
2792 f->do_oop((oop*) &_exception_oop);
2793 f->do_oop((oop*) &_pending_async_exception);
2794
2795 if (jvmti_thread_state() != NULL) {
2796 jvmti_thread_state()->oops_do(f);
2797 }
2798 }
2799
2800 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2801 Thread::nmethods_do(cf); // (super method is a no-op)
2802
2803 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2804 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2805
2806 if (has_last_Java_frame()) {
2807 // Traverse the execution stack
2808 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2809 fst.current()->nmethods_do(cf);
2810 }
2811 }
2812 }
2813
2814 void JavaThread::metadata_do(void f(Metadata*)) {
2815 Thread::metadata_do(f);
2816 if (has_last_Java_frame()) {
2817 // Traverse the execution stack to call f() on the methods in the stack
2818 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2819 fst.current()->metadata_do(f);
2820 }
2821 } else if (is_Compiler_thread()) {
2822 // need to walk ciMetadata in current compile tasks to keep alive.
2823 CompilerThread* ct = (CompilerThread*)this;
2824 if (ct->env() != NULL) {
2825 ct->env()->metadata_do(f);
2826 }
2827 }
2828 }
2829
2830 // Printing
2831 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2832 switch (_thread_state) {
2833 case _thread_uninitialized: return "_thread_uninitialized";
2834 case _thread_new: return "_thread_new";
2835 case _thread_new_trans: return "_thread_new_trans";
2836 case _thread_in_native: return "_thread_in_native";
2837 case _thread_in_native_trans: return "_thread_in_native_trans";
2838 case _thread_in_vm: return "_thread_in_vm";
2839 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2840 case _thread_in_Java: return "_thread_in_Java";
2841 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2842 case _thread_blocked: return "_thread_blocked";
2843 case _thread_blocked_trans: return "_thread_blocked_trans";
2844 default: return "unknown thread state";
2845 }
2846 }
2847
2848 #ifndef PRODUCT
2849 void JavaThread::print_thread_state_on(outputStream *st) const {
2850 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2851 };
2852 void JavaThread::print_thread_state() const {
2853 print_thread_state_on(tty);
2854 };
2855 #endif // PRODUCT
2856
2857 // Called by Threads::print() for VM_PrintThreads operation
2858 void JavaThread::print_on(outputStream *st) const {
2859 st->print("\"%s\" ", get_thread_name());
2860 oop thread_oop = threadObj();
2861 if (thread_oop != NULL) {
2862 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2863 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2864 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2865 }
2866 Thread::print_on(st);
2867 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2868 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2869 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2870 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2871 }
2872 #ifndef PRODUCT
2873 print_thread_state_on(st);
2874 _safepoint_state->print_on(st);
2875 #endif // PRODUCT
2876 }
2877
2878 // Called by fatal error handler. The difference between this and
2879 // JavaThread::print() is that we can't grab lock or allocate memory.
2880 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2881 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2882 oop thread_obj = threadObj();
2883 if (thread_obj != NULL) {
2884 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2885 }
2886 st->print(" [");
2887 st->print("%s", _get_thread_state_name(_thread_state));
2888 if (osthread()) {
2889 st->print(", id=%d", osthread()->thread_id());
2890 }
2891 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2892 _stack_base - _stack_size, _stack_base);
2893 st->print("]");
2894 return;
2895 }
2896
2897 // Verification
2898
2899 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2900
2901 void JavaThread::verify() {
2902 // Verify oops in the thread.
2903 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2904
2905 // Verify the stack frames.
2906 frames_do(frame_verify);
2907 }
2908
2909 // CR 6300358 (sub-CR 2137150)
2910 // Most callers of this method assume that it can't return NULL but a
2911 // thread may not have a name whilst it is in the process of attaching to
2912 // the VM - see CR 6412693, and there are places where a JavaThread can be
2913 // seen prior to having it's threadObj set (eg JNI attaching threads and
2914 // if vm exit occurs during initialization). These cases can all be accounted
2915 // for such that this method never returns NULL.
2916 const char* JavaThread::get_thread_name() const {
2917 #ifdef ASSERT
2918 // early safepoints can hit while current thread does not yet have TLS
2919 if (!SafepointSynchronize::is_at_safepoint()) {
2920 Thread *cur = Thread::current();
2921 if (!(cur->is_Java_thread() && cur == this)) {
2922 // Current JavaThreads are allowed to get their own name without
2923 // the Threads_lock.
2924 assert_locked_or_safepoint(Threads_lock);
2925 }
2926 }
2927 #endif // ASSERT
2928 return get_thread_name_string();
2929 }
2930
2931 // Returns a non-NULL representation of this thread's name, or a suitable
2932 // descriptive string if there is no set name
2933 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2934 const char* name_str;
2935 oop thread_obj = threadObj();
2936 if (thread_obj != NULL) {
2937 oop name = java_lang_Thread::name(thread_obj);
2938 if (name != NULL) {
2939 if (buf == NULL) {
2940 name_str = java_lang_String::as_utf8_string(name);
2941 }
2942 else {
2943 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2944 }
2945 }
2946 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2947 name_str = "<no-name - thread is attaching>";
2948 }
2949 else {
2950 name_str = Thread::name();
2951 }
2952 }
2953 else {
2954 name_str = Thread::name();
2955 }
2956 assert(name_str != NULL, "unexpected NULL thread name");
2957 return name_str;
2958 }
2959
2960
2961 const char* JavaThread::get_threadgroup_name() const {
2962 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2963 oop thread_obj = threadObj();
2964 if (thread_obj != NULL) {
2965 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2966 if (thread_group != NULL) {
2967 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2968 // ThreadGroup.name can be null
2969 if (name != NULL) {
2970 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2971 return str;
2972 }
2973 }
2974 }
2975 return NULL;
2976 }
2977
2978 const char* JavaThread::get_parent_name() const {
2979 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2980 oop thread_obj = threadObj();
2981 if (thread_obj != NULL) {
2982 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2983 if (thread_group != NULL) {
2984 oop parent = java_lang_ThreadGroup::parent(thread_group);
2985 if (parent != NULL) {
2986 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2987 // ThreadGroup.name can be null
2988 if (name != NULL) {
2989 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2990 return str;
2991 }
2992 }
2993 }
2994 }
2995 return NULL;
2996 }
2997
2998 ThreadPriority JavaThread::java_priority() const {
2999 oop thr_oop = threadObj();
3000 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3001 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3002 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3003 return priority;
3004 }
3005
3006 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3007
3008 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3009 // Link Java Thread object <-> C++ Thread
3010
3011 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3012 // and put it into a new Handle. The Handle "thread_oop" can then
3013 // be used to pass the C++ thread object to other methods.
3014
3015 // Set the Java level thread object (jthread) field of the
3016 // new thread (a JavaThread *) to C++ thread object using the
3017 // "thread_oop" handle.
3018
3019 // Set the thread field (a JavaThread *) of the
3020 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3021
3022 Handle thread_oop(Thread::current(),
3023 JNIHandles::resolve_non_null(jni_thread));
3024 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3025 "must be initialized");
3026 set_threadObj(thread_oop());
3027 java_lang_Thread::set_thread(thread_oop(), this);
3028
3029 if (prio == NoPriority) {
3030 prio = java_lang_Thread::priority(thread_oop());
3031 assert(prio != NoPriority, "A valid priority should be present");
3032 }
3033
3034 // Push the Java priority down to the native thread; needs Threads_lock
3035 Thread::set_priority(this, prio);
3036
3037 prepare_ext();
3038
3039 // Add the new thread to the Threads list and set it in motion.
3040 // We must have threads lock in order to call Threads::add.
3041 // It is crucial that we do not block before the thread is
3042 // added to the Threads list for if a GC happens, then the java_thread oop
3043 // will not be visited by GC.
3044 Threads::add(this);
3045 }
3046
3047 oop JavaThread::current_park_blocker() {
3048 // Support for JSR-166 locks
3049 oop thread_oop = threadObj();
3050 if (thread_oop != NULL &&
3051 JDK_Version::current().supports_thread_park_blocker()) {
3052 return java_lang_Thread::park_blocker(thread_oop);
3053 }
3054 return NULL;
3055 }
3056
3057
3058 void JavaThread::print_stack_on(outputStream* st) {
3059 if (!has_last_Java_frame()) return;
3060 ResourceMark rm;
3061 HandleMark hm;
3062
3063 RegisterMap reg_map(this);
3064 vframe* start_vf = last_java_vframe(®_map);
3065 int count = 0;
3066 for (vframe* f = start_vf; f; f = f->sender() ) {
3067 if (f->is_java_frame()) {
3068 javaVFrame* jvf = javaVFrame::cast(f);
3069 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3070
3071 // Print out lock information
3072 if (JavaMonitorsInStackTrace) {
3073 jvf->print_lock_info_on(st, count);
3074 }
3075 } else {
3076 // Ignore non-Java frames
3077 }
3078
3079 // Bail-out case for too deep stacks
3080 count++;
3081 if (MaxJavaStackTraceDepth == count) return;
3082 }
3083 }
3084
3085
3086 // JVMTI PopFrame support
3087 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3088 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3089 if (in_bytes(size_in_bytes) != 0) {
3090 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3091 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3092 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3093 }
3094 }
3095
3096 void* JavaThread::popframe_preserved_args() {
3097 return _popframe_preserved_args;
3098 }
3099
3100 ByteSize JavaThread::popframe_preserved_args_size() {
3101 return in_ByteSize(_popframe_preserved_args_size);
3102 }
3103
3104 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3105 int sz = in_bytes(popframe_preserved_args_size());
3106 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3107 return in_WordSize(sz / wordSize);
3108 }
3109
3110 void JavaThread::popframe_free_preserved_args() {
3111 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3112 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3113 _popframe_preserved_args = NULL;
3114 _popframe_preserved_args_size = 0;
3115 }
3116
3117 #ifndef PRODUCT
3118
3119 void JavaThread::trace_frames() {
3120 tty->print_cr("[Describe stack]");
3121 int frame_no = 1;
3122 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3123 tty->print(" %d. ", frame_no++);
3124 fst.current()->print_value_on(tty,this);
3125 tty->cr();
3126 }
3127 }
3128
3129 class PrintAndVerifyOopClosure: public OopClosure {
3130 protected:
3131 template <class T> inline void do_oop_work(T* p) {
3132 oop obj = oopDesc::load_decode_heap_oop(p);
3133 if (obj == NULL) return;
3134 tty->print(INTPTR_FORMAT ": ", p);
3135 if (obj->is_oop_or_null()) {
3136 if (obj->is_objArray()) {
3137 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3138 } else {
3139 obj->print();
3140 }
3141 } else {
3142 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3143 }
3144 tty->cr();
3145 }
3146 public:
3147 virtual void do_oop(oop* p) { do_oop_work(p); }
3148 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3149 };
3150
3151
3152 static void oops_print(frame* f, const RegisterMap *map) {
3153 PrintAndVerifyOopClosure print;
3154 f->print_value();
3155 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3156 }
3157
3158 // Print our all the locations that contain oops and whether they are
3159 // valid or not. This useful when trying to find the oldest frame
3160 // where an oop has gone bad since the frame walk is from youngest to
3161 // oldest.
3162 void JavaThread::trace_oops() {
3163 tty->print_cr("[Trace oops]");
3164 frames_do(oops_print);
3165 }
3166
3167
3168 #ifdef ASSERT
3169 // Print or validate the layout of stack frames
3170 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3171 ResourceMark rm;
3172 PRESERVE_EXCEPTION_MARK;
3173 FrameValues values;
3174 int frame_no = 0;
3175 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3176 fst.current()->describe(values, ++frame_no);
3177 if (depth == frame_no) break;
3178 }
3179 if (validate_only) {
3180 values.validate();
3181 } else {
3182 tty->print_cr("[Describe stack layout]");
3183 values.print(this);
3184 }
3185 }
3186 #endif
3187
3188 void JavaThread::trace_stack_from(vframe* start_vf) {
3189 ResourceMark rm;
3190 int vframe_no = 1;
3191 for (vframe* f = start_vf; f; f = f->sender() ) {
3192 if (f->is_java_frame()) {
3193 javaVFrame::cast(f)->print_activation(vframe_no++);
3194 } else {
3195 f->print();
3196 }
3197 if (vframe_no > StackPrintLimit) {
3198 tty->print_cr("...<more frames>...");
3199 return;
3200 }
3201 }
3202 }
3203
3204
3205 void JavaThread::trace_stack() {
3206 if (!has_last_Java_frame()) return;
3207 ResourceMark rm;
3208 HandleMark hm;
3209 RegisterMap reg_map(this);
3210 trace_stack_from(last_java_vframe(®_map));
3211 }
3212
3213
3214 #endif // PRODUCT
3215
3216
3217 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3218 assert(reg_map != NULL, "a map must be given");
3219 frame f = last_frame();
3220 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3221 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3222 }
3223 return NULL;
3224 }
3225
3226
3227 Klass* JavaThread::security_get_caller_class(int depth) {
3228 vframeStream vfst(this);
3229 vfst.security_get_caller_frame(depth);
3230 if (!vfst.at_end()) {
3231 return vfst.method()->method_holder();
3232 }
3233 return NULL;
3234 }
3235
3236 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3237 assert(thread->is_Compiler_thread(), "must be compiler thread");
3238 CompileBroker::compiler_thread_loop();
3239 }
3240
3241 // Create a CompilerThread
3242 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3243 : JavaThread(&compiler_thread_entry) {
3244 _env = NULL;
3245 _log = NULL;
3246 _task = NULL;
3247 _queue = queue;
3248 _counters = counters;
3249 _buffer_blob = NULL;
3250 _scanned_nmethod = NULL;
3251 _compiler = NULL;
3252
3253 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3254 resource_area()->bias_to(mtCompiler);
3255
3256 #ifndef PRODUCT
3257 _ideal_graph_printer = NULL;
3258 #endif
3259 }
3260
3261 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3262 JavaThread::oops_do(f, cld_f, cf);
3263 if (_scanned_nmethod != NULL && cf != NULL) {
3264 // Safepoints can occur when the sweeper is scanning an nmethod so
3265 // process it here to make sure it isn't unloaded in the middle of
3266 // a scan.
3267 cf->do_code_blob(_scanned_nmethod);
3268 }
3269 }
3270
3271
3272 // ======= Threads ========
3273
3274 // The Threads class links together all active threads, and provides
3275 // operations over all threads. It is protected by its own Mutex
3276 // lock, which is also used in other contexts to protect thread
3277 // operations from having the thread being operated on from exiting
3278 // and going away unexpectedly (e.g., safepoint synchronization)
3279
3280 JavaThread* Threads::_thread_list = NULL;
3281 int Threads::_number_of_threads = 0;
3282 int Threads::_number_of_non_daemon_threads = 0;
3283 int Threads::_return_code = 0;
3284 size_t JavaThread::_stack_size_at_create = 0;
3285 #ifdef ASSERT
3286 bool Threads::_vm_complete = false;
3287 #endif
3288
3289 // All JavaThreads
3290 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3291
3292 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3293 void Threads::threads_do(ThreadClosure* tc) {
3294 assert_locked_or_safepoint(Threads_lock);
3295 // ALL_JAVA_THREADS iterates through all JavaThreads
3296 ALL_JAVA_THREADS(p) {
3297 tc->do_thread(p);
3298 }
3299 // Someday we could have a table or list of all non-JavaThreads.
3300 // For now, just manually iterate through them.
3301 tc->do_thread(VMThread::vm_thread());
3302 Universe::heap()->gc_threads_do(tc);
3303 WatcherThread *wt = WatcherThread::watcher_thread();
3304 // Strictly speaking, the following NULL check isn't sufficient to make sure
3305 // the data for WatcherThread is still valid upon being examined. However,
3306 // considering that WatchThread terminates when the VM is on the way to
3307 // exit at safepoint, the chance of the above is extremely small. The right
3308 // way to prevent termination of WatcherThread would be to acquire
3309 // Terminator_lock, but we can't do that without violating the lock rank
3310 // checking in some cases.
3311 if (wt != NULL)
3312 tc->do_thread(wt);
3313
3314 // If CompilerThreads ever become non-JavaThreads, add them here
3315 }
3316
3317 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3318
3319 extern void JDK_Version_init();
3320
3321 // Preinitialize version info.
3322 VM_Version::early_initialize();
3323
3324 // Check version
3325 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3326
3327 // Initialize the output stream module
3328 ostream_init();
3329
3330 // Process java launcher properties.
3331 Arguments::process_sun_java_launcher_properties(args);
3332
3333 // Initialize the os module before using TLS
3334 os::init();
3335
3336 // Initialize system properties.
3337 Arguments::init_system_properties();
3338
3339 // So that JDK version can be used as a discrimintor when parsing arguments
3340 JDK_Version_init();
3341
3342 // Update/Initialize System properties after JDK version number is known
3343 Arguments::init_version_specific_system_properties();
3344
3345 // Parse arguments
3346 jint parse_result = Arguments::parse(args);
3347 if (parse_result != JNI_OK) return parse_result;
3348
3349 os::init_before_ergo();
3350
3351 jint ergo_result = Arguments::apply_ergo();
3352 if (ergo_result != JNI_OK) return ergo_result;
3353
3354 if (PauseAtStartup) {
3355 os::pause();
3356 }
3357
3358 #ifndef USDT2
3359 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3360 #else /* USDT2 */
3361 HOTSPOT_VM_INIT_BEGIN();
3362 #endif /* USDT2 */
3363
3364 // Record VM creation timing statistics
3365 TraceVmCreationTime create_vm_timer;
3366 create_vm_timer.start();
3367
3368 // Timing (must come after argument parsing)
3369 TraceTime timer("Create VM", TraceStartupTime);
3370
3371 // Initialize the os module after parsing the args
3372 jint os_init_2_result = os::init_2();
3373 if (os_init_2_result != JNI_OK) return os_init_2_result;
3374
3375 jint adjust_after_os_result = Arguments::adjust_after_os();
3376 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3377
3378 // intialize TLS
3379 ThreadLocalStorage::init();
3380
3381 // Initialize output stream logging
3382 ostream_init_log();
3383
3384 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3385 // Must be before create_vm_init_agents()
3386 if (Arguments::init_libraries_at_startup()) {
3387 convert_vm_init_libraries_to_agents();
3388 }
3389
3390 // Launch -agentlib/-agentpath and converted -Xrun agents
3391 if (Arguments::init_agents_at_startup()) {
3392 create_vm_init_agents();
3393 }
3394
3395 // Initialize Threads state
3396 _thread_list = NULL;
3397 _number_of_threads = 0;
3398 _number_of_non_daemon_threads = 0;
3399
3400 // Initialize global data structures and create system classes in heap
3401 vm_init_globals();
3402
3403 // Attach the main thread to this os thread
3404 JavaThread* main_thread = new JavaThread();
3405 main_thread->set_thread_state(_thread_in_vm);
3406 // must do this before set_active_handles and initialize_thread_local_storage
3407 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3408 // change the stack size recorded here to one based on the java thread
3409 // stacksize. This adjusted size is what is used to figure the placement
3410 // of the guard pages.
3411 main_thread->record_stack_base_and_size();
3412 main_thread->initialize_thread_local_storage();
3413
3414 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3415
3416 if (!main_thread->set_as_starting_thread()) {
3417 vm_shutdown_during_initialization(
3418 "Failed necessary internal allocation. Out of swap space");
3419 delete main_thread;
3420 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3421 return JNI_ENOMEM;
3422 }
3423
3424 // Enable guard page *after* os::create_main_thread(), otherwise it would
3425 // crash Linux VM, see notes in os_linux.cpp.
3426 main_thread->create_stack_guard_pages();
3427
3428 // Initialize Java-Level synchronization subsystem
3429 ObjectMonitor::Initialize() ;
3430
3431 // Initialize global modules
3432 jint status = init_globals();
3433 if (status != JNI_OK) {
3434 delete main_thread;
3435 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3436 return status;
3437 }
3438
3439 // Should be done after the heap is fully created
3440 main_thread->cache_global_variables();
3441
3442 HandleMark hm;
3443
3444 { MutexLocker mu(Threads_lock);
3445 Threads::add(main_thread);
3446 }
3447
3448 // Any JVMTI raw monitors entered in onload will transition into
3449 // real raw monitor. VM is setup enough here for raw monitor enter.
3450 JvmtiExport::transition_pending_onload_raw_monitors();
3451
3452 // Create the VMThread
3453 { TraceTime timer("Start VMThread", TraceStartupTime);
3454 VMThread::create();
3455 Thread* vmthread = VMThread::vm_thread();
3456
3457 if (!os::create_thread(vmthread, os::vm_thread))
3458 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3459
3460 // Wait for the VM thread to become ready, and VMThread::run to initialize
3461 // Monitors can have spurious returns, must always check another state flag
3462 {
3463 MutexLocker ml(Notify_lock);
3464 os::start_thread(vmthread);
3465 while (vmthread->active_handles() == NULL) {
3466 Notify_lock->wait();
3467 }
3468 }
3469 }
3470
3471 assert (Universe::is_fully_initialized(), "not initialized");
3472 if (VerifyDuringStartup) {
3473 // Make sure we're starting with a clean slate.
3474 VM_Verify verify_op;
3475 VMThread::execute(&verify_op);
3476 }
3477
3478 EXCEPTION_MARK;
3479
3480 // At this point, the Universe is initialized, but we have not executed
3481 // any byte code. Now is a good time (the only time) to dump out the
3482 // internal state of the JVM for sharing.
3483 if (DumpSharedSpaces) {
3484 MetaspaceShared::preload_and_dump(CHECK_0);
3485 ShouldNotReachHere();
3486 }
3487
3488 // Always call even when there are not JVMTI environments yet, since environments
3489 // may be attached late and JVMTI must track phases of VM execution
3490 JvmtiExport::enter_start_phase();
3491
3492 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3493 JvmtiExport::post_vm_start();
3494
3495 {
3496 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3497
3498 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3499 create_vm_init_libraries();
3500 }
3501
3502 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3503
3504 // Initialize java_lang.System (needed before creating the thread)
3505 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3506 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3507 Handle thread_group = create_initial_thread_group(CHECK_0);
3508 Universe::set_main_thread_group(thread_group());
3509 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3510 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3511 main_thread->set_threadObj(thread_object);
3512 // Set thread status to running since main thread has
3513 // been started and running.
3514 java_lang_Thread::set_thread_status(thread_object,
3515 java_lang_Thread::RUNNABLE);
3516
3517 // The VM creates & returns objects of this class. Make sure it's initialized.
3518 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3519
3520 // The VM preresolves methods to these classes. Make sure that they get initialized
3521 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3522 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3523 call_initializeSystemClass(CHECK_0);
3524
3525 // get the Java runtime name after java.lang.System is initialized
3526 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3527 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3528
3529 // an instance of OutOfMemory exception has been allocated earlier
3530 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3531 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3532 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3533 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3534 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3535 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3536 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3537 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3538 }
3539
3540 // See : bugid 4211085.
3541 // Background : the static initializer of java.lang.Compiler tries to read
3542 // property"java.compiler" and read & write property "java.vm.info".
3543 // When a security manager is installed through the command line
3544 // option "-Djava.security.manager", the above properties are not
3545 // readable and the static initializer for java.lang.Compiler fails
3546 // resulting in a NoClassDefFoundError. This can happen in any
3547 // user code which calls methods in java.lang.Compiler.
3548 // Hack : the hack is to pre-load and initialize this class, so that only
3549 // system domains are on the stack when the properties are read.
3550 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3551 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3552 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3553 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3554 // Once that is done, we should remove this hack.
3555 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3556
3557 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3558 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3559 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3560 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3561 // This should also be taken out as soon as 4211383 gets fixed.
3562 reset_vm_info_property(CHECK_0);
3563
3564 quicken_jni_functions();
3565
3566 // Must be run after init_ft which initializes ft_enabled
3567 if (TRACE_INITIALIZE() != JNI_OK) {
3568 vm_exit_during_initialization("Failed to initialize tracing backend");
3569 }
3570
3571 // Set flag that basic initialization has completed. Used by exceptions and various
3572 // debug stuff, that does not work until all basic classes have been initialized.
3573 set_init_completed();
3574
3575 Metaspace::post_initialize();
3576
3577 #ifndef USDT2
3578 HS_DTRACE_PROBE(hotspot, vm__init__end);
3579 #else /* USDT2 */
3580 HOTSPOT_VM_INIT_END();
3581 #endif /* USDT2 */
3582
3583 // record VM initialization completion time
3584 #if INCLUDE_MANAGEMENT
3585 Management::record_vm_init_completed();
3586 #endif // INCLUDE_MANAGEMENT
3587
3588 // Compute system loader. Note that this has to occur after set_init_completed, since
3589 // valid exceptions may be thrown in the process.
3590 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3591 // set_init_completed has just been called, causing exceptions not to be shortcut
3592 // anymore. We call vm_exit_during_initialization directly instead.
3593 SystemDictionary::compute_java_system_loader(THREAD);
3594 if (HAS_PENDING_EXCEPTION) {
3595 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3596 }
3597
3598 #if INCLUDE_ALL_GCS
3599 // Support for ConcurrentMarkSweep. This should be cleaned up
3600 // and better encapsulated. The ugly nested if test would go away
3601 // once things are properly refactored. XXX YSR
3602 if (UseConcMarkSweepGC || UseG1GC) {
3603 if (UseConcMarkSweepGC) {
3604 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3605 } else {
3606 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3607 }
3608 if (HAS_PENDING_EXCEPTION) {
3609 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3610 }
3611 }
3612 #endif // INCLUDE_ALL_GCS
3613
3614 // Always call even when there are not JVMTI environments yet, since environments
3615 // may be attached late and JVMTI must track phases of VM execution
3616 JvmtiExport::enter_live_phase();
3617
3618 // Signal Dispatcher needs to be started before VMInit event is posted
3619 os::signal_init();
3620
3621 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3622 if (!DisableAttachMechanism) {
3623 AttachListener::vm_start();
3624 if (StartAttachListener || AttachListener::init_at_startup()) {
3625 AttachListener::init();
3626 }
3627 }
3628
3629 // Launch -Xrun agents
3630 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3631 // back-end can launch with -Xdebug -Xrunjdwp.
3632 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3633 create_vm_init_libraries();
3634 }
3635
3636 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3637 JvmtiExport::post_vm_initialized();
3638
3639 if (TRACE_START() != JNI_OK) {
3640 vm_exit_during_initialization("Failed to start tracing backend.");
3641 }
3642
3643 if (CleanChunkPoolAsync) {
3644 Chunk::start_chunk_pool_cleaner_task();
3645 }
3646
3647 // initialize compiler(s)
3648 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3649 CompileBroker::compilation_init();
3650 #endif
3651
3652 if (EnableInvokeDynamic) {
3653 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3654 // It is done after compilers are initialized, because otherwise compilations of
3655 // signature polymorphic MH intrinsics can be missed
3656 // (see SystemDictionary::find_method_handle_intrinsic).
3657 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3658 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3659 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3660 }
3661
3662 #if INCLUDE_MANAGEMENT
3663 Management::initialize(THREAD);
3664 #endif // INCLUDE_MANAGEMENT
3665
3666 if (HAS_PENDING_EXCEPTION) {
3667 // management agent fails to start possibly due to
3668 // configuration problem and is responsible for printing
3669 // stack trace if appropriate. Simply exit VM.
3670 vm_exit(1);
3671 }
3672
3673 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3674 if (MemProfiling) MemProfiler::engage();
3675 StatSampler::engage();
3676 if (CheckJNICalls) JniPeriodicChecker::engage();
3677
3678 BiasedLocking::init();
3679
3680 #if INCLUDE_RTM_OPT
3681 RTMLockingCounters::init();
3682 #endif
3683
3684 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3685 call_postVMInitHook(THREAD);
3686 // The Java side of PostVMInitHook.run must deal with all
3687 // exceptions and provide means of diagnosis.
3688 if (HAS_PENDING_EXCEPTION) {
3689 CLEAR_PENDING_EXCEPTION;
3690 }
3691 }
3692
3693 {
3694 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3695 // Make sure the watcher thread can be started by WatcherThread::start()
3696 // or by dynamic enrollment.
3697 WatcherThread::make_startable();
3698 // Start up the WatcherThread if there are any periodic tasks
3699 // NOTE: All PeriodicTasks should be registered by now. If they
3700 // aren't, late joiners might appear to start slowly (we might
3701 // take a while to process their first tick).
3702 if (PeriodicTask::num_tasks() > 0) {
3703 WatcherThread::start();
3704 }
3705 }
3706
3707 create_vm_timer.end();
3708 #ifdef ASSERT
3709 _vm_complete = true;
3710 #endif
3711 return JNI_OK;
3712 }
3713
3714 // type for the Agent_OnLoad and JVM_OnLoad entry points
3715 extern "C" {
3716 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3717 }
3718 // Find a command line agent library and return its entry point for
3719 // -agentlib: -agentpath: -Xrun
3720 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3721 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3722 OnLoadEntry_t on_load_entry = NULL;
3723 void *library = NULL;
3724
3725 if (!agent->valid()) {
3726 char buffer[JVM_MAXPATHLEN];
3727 char ebuf[1024];
3728 const char *name = agent->name();
3729 const char *msg = "Could not find agent library ";
3730
3731 // First check to see if agent is statically linked into executable
3732 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3733 library = agent->os_lib();
3734 } else if (agent->is_absolute_path()) {
3735 library = os::dll_load(name, ebuf, sizeof ebuf);
3736 if (library == NULL) {
3737 const char *sub_msg = " in absolute path, with error: ";
3738 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3739 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3740 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3741 // If we can't find the agent, exit.
3742 vm_exit_during_initialization(buf, NULL);
3743 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3744 }
3745 } else {
3746 // Try to load the agent from the standard dll directory
3747 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3748 name)) {
3749 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3750 }
3751 if (library == NULL) { // Try the local directory
3752 char ns[1] = {0};
3753 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3754 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3755 }
3756 if (library == NULL) {
3757 const char *sub_msg = " on the library path, with error: ";
3758 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3759 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3760 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3761 // If we can't find the agent, exit.
3762 vm_exit_during_initialization(buf, NULL);
3763 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3764 }
3765 }
3766 }
3767 agent->set_os_lib(library);
3768 agent->set_valid();
3769 }
3770
3771 // Find the OnLoad function.
3772 on_load_entry =
3773 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3774 false,
3775 on_load_symbols,
3776 num_symbol_entries));
3777 return on_load_entry;
3778 }
3779
3780 // Find the JVM_OnLoad entry point
3781 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3782 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3783 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3784 }
3785
3786 // Find the Agent_OnLoad entry point
3787 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3788 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3789 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3790 }
3791
3792 // For backwards compatibility with -Xrun
3793 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3794 // treated like -agentpath:
3795 // Must be called before agent libraries are created
3796 void Threads::convert_vm_init_libraries_to_agents() {
3797 AgentLibrary* agent;
3798 AgentLibrary* next;
3799
3800 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3801 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3802 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3803
3804 // If there is an JVM_OnLoad function it will get called later,
3805 // otherwise see if there is an Agent_OnLoad
3806 if (on_load_entry == NULL) {
3807 on_load_entry = lookup_agent_on_load(agent);
3808 if (on_load_entry != NULL) {
3809 // switch it to the agent list -- so that Agent_OnLoad will be called,
3810 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3811 Arguments::convert_library_to_agent(agent);
3812 } else {
3813 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3814 }
3815 }
3816 }
3817 }
3818
3819 // Create agents for -agentlib: -agentpath: and converted -Xrun
3820 // Invokes Agent_OnLoad
3821 // Called very early -- before JavaThreads exist
3822 void Threads::create_vm_init_agents() {
3823 extern struct JavaVM_ main_vm;
3824 AgentLibrary* agent;
3825
3826 JvmtiExport::enter_onload_phase();
3827
3828 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3829 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3830
3831 if (on_load_entry != NULL) {
3832 // Invoke the Agent_OnLoad function
3833 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3834 if (err != JNI_OK) {
3835 vm_exit_during_initialization("agent library failed to init", agent->name());
3836 }
3837 } else {
3838 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3839 }
3840 }
3841 JvmtiExport::enter_primordial_phase();
3842 }
3843
3844 extern "C" {
3845 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3846 }
3847
3848 void Threads::shutdown_vm_agents() {
3849 // Send any Agent_OnUnload notifications
3850 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3851 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3852 extern struct JavaVM_ main_vm;
3853 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3854
3855 // Find the Agent_OnUnload function.
3856 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3857 os::find_agent_function(agent,
3858 false,
3859 on_unload_symbols,
3860 num_symbol_entries));
3861
3862 // Invoke the Agent_OnUnload function
3863 if (unload_entry != NULL) {
3864 JavaThread* thread = JavaThread::current();
3865 ThreadToNativeFromVM ttn(thread);
3866 HandleMark hm(thread);
3867 (*unload_entry)(&main_vm);
3868 }
3869 }
3870 }
3871
3872 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3873 // Invokes JVM_OnLoad
3874 void Threads::create_vm_init_libraries() {
3875 extern struct JavaVM_ main_vm;
3876 AgentLibrary* agent;
3877
3878 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3879 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3880
3881 if (on_load_entry != NULL) {
3882 // Invoke the JVM_OnLoad function
3883 JavaThread* thread = JavaThread::current();
3884 ThreadToNativeFromVM ttn(thread);
3885 HandleMark hm(thread);
3886 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3887 if (err != JNI_OK) {
3888 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3889 }
3890 } else {
3891 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3892 }
3893 }
3894 }
3895
3896 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3897 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3898
3899 JavaThread* java_thread = NULL;
3900 // Sequential search for now. Need to do better optimization later.
3901 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3902 oop tobj = thread->threadObj();
3903 if (!thread->is_exiting() &&
3904 tobj != NULL &&
3905 java_tid == java_lang_Thread::thread_id(tobj)) {
3906 java_thread = thread;
3907 break;
3908 }
3909 }
3910 return java_thread;
3911 }
3912
3913
3914 // Last thread running calls java.lang.Shutdown.shutdown()
3915 void JavaThread::invoke_shutdown_hooks() {
3916 HandleMark hm(this);
3917
3918 // We could get here with a pending exception, if so clear it now.
3919 if (this->has_pending_exception()) {
3920 this->clear_pending_exception();
3921 }
3922
3923 EXCEPTION_MARK;
3924 Klass* k =
3925 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3926 THREAD);
3927 if (k != NULL) {
3928 // SystemDictionary::resolve_or_null will return null if there was
3929 // an exception. If we cannot load the Shutdown class, just don't
3930 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3931 // and finalizers (if runFinalizersOnExit is set) won't be run.
3932 // Note that if a shutdown hook was registered or runFinalizersOnExit
3933 // was called, the Shutdown class would have already been loaded
3934 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3935 instanceKlassHandle shutdown_klass (THREAD, k);
3936 JavaValue result(T_VOID);
3937 JavaCalls::call_static(&result,
3938 shutdown_klass,
3939 vmSymbols::shutdown_method_name(),
3940 vmSymbols::void_method_signature(),
3941 THREAD);
3942 }
3943 CLEAR_PENDING_EXCEPTION;
3944 }
3945
3946 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3947 // the program falls off the end of main(). Another VM exit path is through
3948 // vm_exit() when the program calls System.exit() to return a value or when
3949 // there is a serious error in VM. The two shutdown paths are not exactly
3950 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3951 // and VM_Exit op at VM level.
3952 //
3953 // Shutdown sequence:
3954 // + Shutdown native memory tracking if it is on
3955 // + Wait until we are the last non-daemon thread to execute
3956 // <-- every thing is still working at this moment -->
3957 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3958 // shutdown hooks, run finalizers if finalization-on-exit
3959 // + Call before_exit(), prepare for VM exit
3960 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3961 // currently the only user of this mechanism is File.deleteOnExit())
3962 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3963 // post thread end and vm death events to JVMTI,
3964 // stop signal thread
3965 // + Call JavaThread::exit(), it will:
3966 // > release JNI handle blocks, remove stack guard pages
3967 // > remove this thread from Threads list
3968 // <-- no more Java code from this thread after this point -->
3969 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3970 // the compiler threads at safepoint
3971 // <-- do not use anything that could get blocked by Safepoint -->
3972 // + Disable tracing at JNI/JVM barriers
3973 // + Set _vm_exited flag for threads that are still running native code
3974 // + Delete this thread
3975 // + Call exit_globals()
3976 // > deletes tty
3977 // > deletes PerfMemory resources
3978 // + Return to caller
3979
3980 bool Threads::destroy_vm() {
3981 JavaThread* thread = JavaThread::current();
3982
3983 #ifdef ASSERT
3984 _vm_complete = false;
3985 #endif
3986 // Wait until we are the last non-daemon thread to execute
3987 { MutexLocker nu(Threads_lock);
3988 while (Threads::number_of_non_daemon_threads() > 1 )
3989 // This wait should make safepoint checks, wait without a timeout,
3990 // and wait as a suspend-equivalent condition.
3991 //
3992 // Note: If the FlatProfiler is running and this thread is waiting
3993 // for another non-daemon thread to finish, then the FlatProfiler
3994 // is waiting for the external suspend request on this thread to
3995 // complete. wait_for_ext_suspend_completion() will eventually
3996 // timeout, but that takes time. Making this wait a suspend-
3997 // equivalent condition solves that timeout problem.
3998 //
3999 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4000 Mutex::_as_suspend_equivalent_flag);
4001 }
4002
4003 // Hang forever on exit if we are reporting an error.
4004 if (ShowMessageBoxOnError && is_error_reported()) {
4005 os::infinite_sleep();
4006 }
4007 os::wait_for_keypress_at_exit();
4008
4009 if (JDK_Version::is_jdk12x_version()) {
4010 // We are the last thread running, so check if finalizers should be run.
4011 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4012 HandleMark rm(thread);
4013 Universe::run_finalizers_on_exit();
4014 } else {
4015 // run Java level shutdown hooks
4016 thread->invoke_shutdown_hooks();
4017 }
4018
4019 before_exit(thread);
4020
4021 thread->exit(true);
4022
4023 // Stop VM thread.
4024 {
4025 // 4945125 The vm thread comes to a safepoint during exit.
4026 // GC vm_operations can get caught at the safepoint, and the
4027 // heap is unparseable if they are caught. Grab the Heap_lock
4028 // to prevent this. The GC vm_operations will not be able to
4029 // queue until after the vm thread is dead. After this point,
4030 // we'll never emerge out of the safepoint before the VM exits.
4031
4032 MutexLocker ml(Heap_lock);
4033
4034 VMThread::wait_for_vm_thread_exit();
4035 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4036 VMThread::destroy();
4037 }
4038
4039 // clean up ideal graph printers
4040 #if defined(COMPILER2) && !defined(PRODUCT)
4041 IdealGraphPrinter::clean_up();
4042 #endif
4043
4044 // Now, all Java threads are gone except daemon threads. Daemon threads
4045 // running Java code or in VM are stopped by the Safepoint. However,
4046 // daemon threads executing native code are still running. But they
4047 // will be stopped at native=>Java/VM barriers. Note that we can't
4048 // simply kill or suspend them, as it is inherently deadlock-prone.
4049
4050 #ifndef PRODUCT
4051 // disable function tracing at JNI/JVM barriers
4052 TraceJNICalls = false;
4053 TraceJVMCalls = false;
4054 TraceRuntimeCalls = false;
4055 #endif
4056
4057 VM_Exit::set_vm_exited();
4058
4059 notify_vm_shutdown();
4060
4061 delete thread;
4062
4063 // exit_globals() will delete tty
4064 exit_globals();
4065
4066 return true;
4067 }
4068
4069
4070 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4071 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4072 return is_supported_jni_version(version);
4073 }
4074
4075
4076 jboolean Threads::is_supported_jni_version(jint version) {
4077 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4078 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4079 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4080 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4081 return JNI_FALSE;
4082 }
4083
4084
4085 void Threads::add(JavaThread* p, bool force_daemon) {
4086 // The threads lock must be owned at this point
4087 assert_locked_or_safepoint(Threads_lock);
4088
4089 // See the comment for this method in thread.hpp for its purpose and
4090 // why it is called here.
4091 p->initialize_queues();
4092 p->set_next(_thread_list);
4093 _thread_list = p;
4094 _number_of_threads++;
4095 oop threadObj = p->threadObj();
4096 bool daemon = true;
4097 // Bootstrapping problem: threadObj can be null for initial
4098 // JavaThread (or for threads attached via JNI)
4099 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4100 _number_of_non_daemon_threads++;
4101 daemon = false;
4102 }
4103
4104 ThreadService::add_thread(p, daemon);
4105
4106 // Possible GC point.
4107 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4108 }
4109
4110 void Threads::remove(JavaThread* p) {
4111 // Extra scope needed for Thread_lock, so we can check
4112 // that we do not remove thread without safepoint code notice
4113 { MutexLocker ml(Threads_lock);
4114
4115 assert(includes(p), "p must be present");
4116
4117 JavaThread* current = _thread_list;
4118 JavaThread* prev = NULL;
4119
4120 while (current != p) {
4121 prev = current;
4122 current = current->next();
4123 }
4124
4125 if (prev) {
4126 prev->set_next(current->next());
4127 } else {
4128 _thread_list = p->next();
4129 }
4130 _number_of_threads--;
4131 oop threadObj = p->threadObj();
4132 bool daemon = true;
4133 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4134 _number_of_non_daemon_threads--;
4135 daemon = false;
4136
4137 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4138 // on destroy_vm will wake up.
4139 if (number_of_non_daemon_threads() == 1)
4140 Threads_lock->notify_all();
4141 }
4142 ThreadService::remove_thread(p, daemon);
4143
4144 // Make sure that safepoint code disregard this thread. This is needed since
4145 // the thread might mess around with locks after this point. This can cause it
4146 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4147 // of this thread since it is removed from the queue.
4148 p->set_terminated_value();
4149 } // unlock Threads_lock
4150
4151 // Since Events::log uses a lock, we grab it outside the Threads_lock
4152 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4153 }
4154
4155 // Threads_lock must be held when this is called (or must be called during a safepoint)
4156 bool Threads::includes(JavaThread* p) {
4157 assert(Threads_lock->is_locked(), "sanity check");
4158 ALL_JAVA_THREADS(q) {
4159 if (q == p ) {
4160 return true;
4161 }
4162 }
4163 return false;
4164 }
4165
4166 // Operations on the Threads list for GC. These are not explicitly locked,
4167 // but the garbage collector must provide a safe context for them to run.
4168 // In particular, these things should never be called when the Threads_lock
4169 // is held by some other thread. (Note: the Safepoint abstraction also
4170 // uses the Threads_lock to gurantee this property. It also makes sure that
4171 // all threads gets blocked when exiting or starting).
4172
4173 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4174 ALL_JAVA_THREADS(p) {
4175 p->oops_do(f, cld_f, cf);
4176 }
4177 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4178 }
4179
4180 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4181 // Introduce a mechanism allowing parallel threads to claim threads as
4182 // root groups. Overhead should be small enough to use all the time,
4183 // even in sequential code.
4184 SharedHeap* sh = SharedHeap::heap();
4185 // Cannot yet substitute active_workers for n_par_threads
4186 // because of G1CollectedHeap::verify() use of
4187 // SharedHeap::process_roots(). n_par_threads == 0 will
4188 // turn off parallelism in process_roots while active_workers
4189 // is being used for parallelism elsewhere.
4190 bool is_par = sh->n_par_threads() > 0;
4191 assert(!is_par ||
4192 (SharedHeap::heap()->n_par_threads() ==
4193 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4194 int cp = SharedHeap::heap()->strong_roots_parity();
4195 ALL_JAVA_THREADS(p) {
4196 if (p->claim_oops_do(is_par, cp)) {
4197 p->oops_do(f, cld_f, cf);
4198 }
4199 }
4200 VMThread* vmt = VMThread::vm_thread();
4201 if (vmt->claim_oops_do(is_par, cp)) {
4202 vmt->oops_do(f, cld_f, cf);
4203 }
4204 }
4205
4206 #if INCLUDE_ALL_GCS
4207 // Used by ParallelScavenge
4208 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4209 ALL_JAVA_THREADS(p) {
4210 q->enqueue(new ThreadRootsTask(p));
4211 }
4212 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4213 }
4214
4215 // Used by Parallel Old
4216 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4217 ALL_JAVA_THREADS(p) {
4218 q->enqueue(new ThreadRootsMarkingTask(p));
4219 }
4220 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4221 }
4222 #endif // INCLUDE_ALL_GCS
4223
4224 void Threads::nmethods_do(CodeBlobClosure* cf) {
4225 ALL_JAVA_THREADS(p) {
4226 p->nmethods_do(cf);
4227 }
4228 VMThread::vm_thread()->nmethods_do(cf);
4229 }
4230
4231 void Threads::metadata_do(void f(Metadata*)) {
4232 ALL_JAVA_THREADS(p) {
4233 p->metadata_do(f);
4234 }
4235 }
4236
4237 void Threads::gc_epilogue() {
4238 ALL_JAVA_THREADS(p) {
4239 p->gc_epilogue();
4240 }
4241 }
4242
4243 void Threads::gc_prologue() {
4244 ALL_JAVA_THREADS(p) {
4245 p->gc_prologue();
4246 }
4247 }
4248
4249 void Threads::deoptimized_wrt_marked_nmethods() {
4250 ALL_JAVA_THREADS(p) {
4251 p->deoptimized_wrt_marked_nmethods();
4252 }
4253 }
4254
4255
4256 // Get count Java threads that are waiting to enter the specified monitor.
4257 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4258 address monitor, bool doLock) {
4259 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4260 "must grab Threads_lock or be at safepoint");
4261 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4262
4263 int i = 0;
4264 {
4265 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4266 ALL_JAVA_THREADS(p) {
4267 if (p->is_Compiler_thread()) continue;
4268
4269 address pending = (address)p->current_pending_monitor();
4270 if (pending == monitor) { // found a match
4271 if (i < count) result->append(p); // save the first count matches
4272 i++;
4273 }
4274 }
4275 }
4276 return result;
4277 }
4278
4279
4280 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4281 assert(doLock ||
4282 Threads_lock->owned_by_self() ||
4283 SafepointSynchronize::is_at_safepoint(),
4284 "must grab Threads_lock or be at safepoint");
4285
4286 // NULL owner means not locked so we can skip the search
4287 if (owner == NULL) return NULL;
4288
4289 {
4290 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4291 ALL_JAVA_THREADS(p) {
4292 // first, see if owner is the address of a Java thread
4293 if (owner == (address)p) return p;
4294 }
4295 }
4296 // Cannot assert on lack of success here since this function may be
4297 // used by code that is trying to report useful problem information
4298 // like deadlock detection.
4299 if (UseHeavyMonitors) return NULL;
4300
4301 //
4302 // If we didn't find a matching Java thread and we didn't force use of
4303 // heavyweight monitors, then the owner is the stack address of the
4304 // Lock Word in the owning Java thread's stack.
4305 //
4306 JavaThread* the_owner = NULL;
4307 {
4308 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4309 ALL_JAVA_THREADS(q) {
4310 if (q->is_lock_owned(owner)) {
4311 the_owner = q;
4312 break;
4313 }
4314 }
4315 }
4316 // cannot assert on lack of success here; see above comment
4317 return the_owner;
4318 }
4319
4320 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4321 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4322 char buf[32];
4323 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4324
4325 st->print_cr("Full thread dump %s (%s %s):",
4326 Abstract_VM_Version::vm_name(),
4327 Abstract_VM_Version::vm_release(),
4328 Abstract_VM_Version::vm_info_string()
4329 );
4330 st->cr();
4331
4332 #if INCLUDE_ALL_GCS
4333 // Dump concurrent locks
4334 ConcurrentLocksDump concurrent_locks;
4335 if (print_concurrent_locks) {
4336 concurrent_locks.dump_at_safepoint();
4337 }
4338 #endif // INCLUDE_ALL_GCS
4339
4340 ALL_JAVA_THREADS(p) {
4341 ResourceMark rm;
4342 p->print_on(st);
4343 if (print_stacks) {
4344 if (internal_format) {
4345 p->trace_stack();
4346 } else {
4347 p->print_stack_on(st);
4348 }
4349 }
4350 st->cr();
4351 #if INCLUDE_ALL_GCS
4352 if (print_concurrent_locks) {
4353 concurrent_locks.print_locks_on(p, st);
4354 }
4355 #endif // INCLUDE_ALL_GCS
4356 }
4357
4358 VMThread::vm_thread()->print_on(st);
4359 st->cr();
4360 Universe::heap()->print_gc_threads_on(st);
4361 WatcherThread* wt = WatcherThread::watcher_thread();
4362 if (wt != NULL) {
4363 wt->print_on(st);
4364 st->cr();
4365 }
4366 CompileBroker::print_compiler_threads_on(st);
4367 st->flush();
4368 }
4369
4370 // Threads::print_on_error() is called by fatal error handler. It's possible
4371 // that VM is not at safepoint and/or current thread is inside signal handler.
4372 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4373 // memory (even in resource area), it might deadlock the error handler.
4374 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4375 bool found_current = false;
4376 st->print_cr("Java Threads: ( => current thread )");
4377 ALL_JAVA_THREADS(thread) {
4378 bool is_current = (current == thread);
4379 found_current = found_current || is_current;
4380
4381 st->print("%s", is_current ? "=>" : " ");
4382
4383 st->print(PTR_FORMAT, thread);
4384 st->print(" ");
4385 thread->print_on_error(st, buf, buflen);
4386 st->cr();
4387 }
4388 st->cr();
4389
4390 st->print_cr("Other Threads:");
4391 if (VMThread::vm_thread()) {
4392 bool is_current = (current == VMThread::vm_thread());
4393 found_current = found_current || is_current;
4394 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4395
4396 st->print(PTR_FORMAT, VMThread::vm_thread());
4397 st->print(" ");
4398 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4399 st->cr();
4400 }
4401 WatcherThread* wt = WatcherThread::watcher_thread();
4402 if (wt != NULL) {
4403 bool is_current = (current == wt);
4404 found_current = found_current || is_current;
4405 st->print("%s", is_current ? "=>" : " ");
4406
4407 st->print(PTR_FORMAT, wt);
4408 st->print(" ");
4409 wt->print_on_error(st, buf, buflen);
4410 st->cr();
4411 }
4412 if (!found_current) {
4413 st->cr();
4414 st->print("=>" PTR_FORMAT " (exited) ", current);
4415 current->print_on_error(st, buf, buflen);
4416 st->cr();
4417 }
4418 }
4419
4420 // Internal SpinLock and Mutex
4421 // Based on ParkEvent
4422
4423 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4424 //
4425 // We employ SpinLocks _only for low-contention, fixed-length
4426 // short-duration critical sections where we're concerned
4427 // about native mutex_t or HotSpot Mutex:: latency.
4428 // The mux construct provides a spin-then-block mutual exclusion
4429 // mechanism.
4430 //
4431 // Testing has shown that contention on the ListLock guarding gFreeList
4432 // is common. If we implement ListLock as a simple SpinLock it's common
4433 // for the JVM to devolve to yielding with little progress. This is true
4434 // despite the fact that the critical sections protected by ListLock are
4435 // extremely short.
4436 //
4437 // TODO-FIXME: ListLock should be of type SpinLock.
4438 // We should make this a 1st-class type, integrated into the lock
4439 // hierarchy as leaf-locks. Critically, the SpinLock structure
4440 // should have sufficient padding to avoid false-sharing and excessive
4441 // cache-coherency traffic.
4442
4443
4444 typedef volatile int SpinLockT ;
4445
4446 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4447 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4448 return ; // normal fast-path return
4449 }
4450
4451 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4452 TEVENT (SpinAcquire - ctx) ;
4453 int ctr = 0 ;
4454 int Yields = 0 ;
4455 for (;;) {
4456 while (*adr != 0) {
4457 ++ctr ;
4458 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4459 if (Yields > 5) {
4460 os::naked_short_sleep(1);
4461 } else {
4462 os::NakedYield() ;
4463 ++Yields ;
4464 }
4465 } else {
4466 SpinPause() ;
4467 }
4468 }
4469 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4470 }
4471 }
4472
4473 void Thread::SpinRelease (volatile int * adr) {
4474 assert (*adr != 0, "invariant") ;
4475 OrderAccess::fence() ; // guarantee at least release consistency.
4476 // Roach-motel semantics.
4477 // It's safe if subsequent LDs and STs float "up" into the critical section,
4478 // but prior LDs and STs within the critical section can't be allowed
4479 // to reorder or float past the ST that releases the lock.
4480 *adr = 0 ;
4481 }
4482
4483 // muxAcquire and muxRelease:
4484 //
4485 // * muxAcquire and muxRelease support a single-word lock-word construct.
4486 // The LSB of the word is set IFF the lock is held.
4487 // The remainder of the word points to the head of a singly-linked list
4488 // of threads blocked on the lock.
4489 //
4490 // * The current implementation of muxAcquire-muxRelease uses its own
4491 // dedicated Thread._MuxEvent instance. If we're interested in
4492 // minimizing the peak number of extant ParkEvent instances then
4493 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4494 // as certain invariants were satisfied. Specifically, care would need
4495 // to be taken with regards to consuming unpark() "permits".
4496 // A safe rule of thumb is that a thread would never call muxAcquire()
4497 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4498 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4499 // consume an unpark() permit intended for monitorenter, for instance.
4500 // One way around this would be to widen the restricted-range semaphore
4501 // implemented in park(). Another alternative would be to provide
4502 // multiple instances of the PlatformEvent() for each thread. One
4503 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4504 //
4505 // * Usage:
4506 // -- Only as leaf locks
4507 // -- for short-term locking only as muxAcquire does not perform
4508 // thread state transitions.
4509 //
4510 // Alternatives:
4511 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4512 // but with parking or spin-then-park instead of pure spinning.
4513 // * Use Taura-Oyama-Yonenzawa locks.
4514 // * It's possible to construct a 1-0 lock if we encode the lockword as
4515 // (List,LockByte). Acquire will CAS the full lockword while Release
4516 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4517 // acquiring threads use timers (ParkTimed) to detect and recover from
4518 // the stranding window. Thread/Node structures must be aligned on 256-byte
4519 // boundaries by using placement-new.
4520 // * Augment MCS with advisory back-link fields maintained with CAS().
4521 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4522 // The validity of the backlinks must be ratified before we trust the value.
4523 // If the backlinks are invalid the exiting thread must back-track through the
4524 // the forward links, which are always trustworthy.
4525 // * Add a successor indication. The LockWord is currently encoded as
4526 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4527 // to provide the usual futile-wakeup optimization.
4528 // See RTStt for details.
4529 // * Consider schedctl.sc_nopreempt to cover the critical section.
4530 //
4531
4532
4533 typedef volatile intptr_t MutexT ; // Mux Lock-word
4534 enum MuxBits { LOCKBIT = 1 } ;
4535
4536 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4537 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4538 if (w == 0) return ;
4539 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4540 return ;
4541 }
4542
4543 TEVENT (muxAcquire - Contention) ;
4544 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4545 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4546 for (;;) {
4547 int its = (os::is_MP() ? 100 : 0) + 1 ;
4548
4549 // Optional spin phase: spin-then-park strategy
4550 while (--its >= 0) {
4551 w = *Lock ;
4552 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4553 return ;
4554 }
4555 }
4556
4557 Self->reset() ;
4558 Self->OnList = intptr_t(Lock) ;
4559 // The following fence() isn't _strictly necessary as the subsequent
4560 // CAS() both serializes execution and ratifies the fetched *Lock value.
4561 OrderAccess::fence();
4562 for (;;) {
4563 w = *Lock ;
4564 if ((w & LOCKBIT) == 0) {
4565 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4566 Self->OnList = 0 ; // hygiene - allows stronger asserts
4567 return ;
4568 }
4569 continue ; // Interference -- *Lock changed -- Just retry
4570 }
4571 assert (w & LOCKBIT, "invariant") ;
4572 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4573 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4574 }
4575
4576 while (Self->OnList != 0) {
4577 Self->park() ;
4578 }
4579 }
4580 }
4581
4582 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4583 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4584 if (w == 0) return ;
4585 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4586 return ;
4587 }
4588
4589 TEVENT (muxAcquire - Contention) ;
4590 ParkEvent * ReleaseAfter = NULL ;
4591 if (ev == NULL) {
4592 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4593 }
4594 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4595 for (;;) {
4596 guarantee (ev->OnList == 0, "invariant") ;
4597 int its = (os::is_MP() ? 100 : 0) + 1 ;
4598
4599 // Optional spin phase: spin-then-park strategy
4600 while (--its >= 0) {
4601 w = *Lock ;
4602 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4603 if (ReleaseAfter != NULL) {
4604 ParkEvent::Release (ReleaseAfter) ;
4605 }
4606 return ;
4607 }
4608 }
4609
4610 ev->reset() ;
4611 ev->OnList = intptr_t(Lock) ;
4612 // The following fence() isn't _strictly necessary as the subsequent
4613 // CAS() both serializes execution and ratifies the fetched *Lock value.
4614 OrderAccess::fence();
4615 for (;;) {
4616 w = *Lock ;
4617 if ((w & LOCKBIT) == 0) {
4618 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4619 ev->OnList = 0 ;
4620 // We call ::Release while holding the outer lock, thus
4621 // artificially lengthening the critical section.
4622 // Consider deferring the ::Release() until the subsequent unlock(),
4623 // after we've dropped the outer lock.
4624 if (ReleaseAfter != NULL) {
4625 ParkEvent::Release (ReleaseAfter) ;
4626 }
4627 return ;
4628 }
4629 continue ; // Interference -- *Lock changed -- Just retry
4630 }
4631 assert (w & LOCKBIT, "invariant") ;
4632 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4633 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4634 }
4635
4636 while (ev->OnList != 0) {
4637 ev->park() ;
4638 }
4639 }
4640 }
4641
4642 // Release() must extract a successor from the list and then wake that thread.
4643 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4644 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4645 // Release() would :
4646 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4647 // (B) Extract a successor from the private list "in-hand"
4648 // (C) attempt to CAS() the residual back into *Lock over null.
4649 // If there were any newly arrived threads and the CAS() would fail.
4650 // In that case Release() would detach the RATs, re-merge the list in-hand
4651 // with the RATs and repeat as needed. Alternately, Release() might
4652 // detach and extract a successor, but then pass the residual list to the wakee.
4653 // The wakee would be responsible for reattaching and remerging before it
4654 // competed for the lock.
4655 //
4656 // Both "pop" and DMR are immune from ABA corruption -- there can be
4657 // multiple concurrent pushers, but only one popper or detacher.
4658 // This implementation pops from the head of the list. This is unfair,
4659 // but tends to provide excellent throughput as hot threads remain hot.
4660 // (We wake recently run threads first).
4661
4662 void Thread::muxRelease (volatile intptr_t * Lock) {
4663 for (;;) {
4664 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4665 assert (w & LOCKBIT, "invariant") ;
4666 if (w == LOCKBIT) return ;
4667 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4668 assert (List != NULL, "invariant") ;
4669 assert (List->OnList == intptr_t(Lock), "invariant") ;
4670 ParkEvent * nxt = List->ListNext ;
4671
4672 // The following CAS() releases the lock and pops the head element.
4673 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4674 continue ;
4675 }
4676 List->OnList = 0 ;
4677 OrderAccess::fence() ;
4678 List->unpark () ;
4679 return ;
4680 }
4681 }
4682
4683
4684 void Threads::verify() {
4685 ALL_JAVA_THREADS(p) {
4686 p->verify();
4687 }
4688 VMThread* thread = VMThread::vm_thread();
4689 if (thread != NULL) thread->verify();
4690 }