1 /*
2 * Copyright (c) 1997, 2019, 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 = 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_thread(THREAD_TRACE_ID(this));
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_thread(THREAD_TRACE_ID(this));
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 #if INCLUDE_TRACE
2189 if (is_trace_suspend()) {
2190 TRACE_SUSPEND_THREAD(this);
2191 }
2192 #endif
2193 }
2194
2195 void JavaThread::send_thread_stop(oop java_throwable) {
2196 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2197 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2198 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2199
2200 // Do not throw asynchronous exceptions against the compiler thread
2201 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2202 if (is_Compiler_thread()) return;
2203
2204 {
2205 // Actually throw the Throwable against the target Thread - however
2206 // only if there is no thread death exception installed already.
2207 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2208 // If the topmost frame is a runtime stub, then we are calling into
2209 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2210 // must deoptimize the caller before continuing, as the compiled exception handler table
2211 // may not be valid
2212 if (has_last_Java_frame()) {
2213 frame f = last_frame();
2214 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2215 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2216 RegisterMap reg_map(this, UseBiasedLocking);
2217 frame compiled_frame = f.sender(®_map);
2218 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2219 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2220 }
2221 }
2222 }
2223
2224 // Set async. pending exception in thread.
2225 set_pending_async_exception(java_throwable);
2226
2227 if (TraceExceptions) {
2228 ResourceMark rm;
2229 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2230 }
2231 // for AbortVMOnException flag
2232 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2233 }
2234 }
2235
2236
2237 // Interrupt thread so it will wake up from a potential wait()
2238 Thread::interrupt(this);
2239 }
2240
2241 // External suspension mechanism.
2242 //
2243 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2244 // to any VM_locks and it is at a transition
2245 // Self-suspension will happen on the transition out of the vm.
2246 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2247 //
2248 // Guarantees on return:
2249 // + Target thread will not execute any new bytecode (that's why we need to
2250 // force a safepoint)
2251 // + Target thread will not enter any new monitors
2252 //
2253 void JavaThread::java_suspend() {
2254 { MutexLocker mu(Threads_lock);
2255 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2256 return;
2257 }
2258 }
2259
2260 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2261 if (!is_external_suspend()) {
2262 // a racing resume has cancelled us; bail out now
2263 return;
2264 }
2265
2266 // suspend is done
2267 uint32_t debug_bits = 0;
2268 // Warning: is_ext_suspend_completed() may temporarily drop the
2269 // SR_lock to allow the thread to reach a stable thread state if
2270 // it is currently in a transient thread state.
2271 if (is_ext_suspend_completed(false /* !called_by_wait */,
2272 SuspendRetryDelay, &debug_bits) ) {
2273 return;
2274 }
2275 }
2276
2277 VM_ForceSafepoint vm_suspend;
2278 VMThread::execute(&vm_suspend);
2279 }
2280
2281 // Part II of external suspension.
2282 // A JavaThread self suspends when it detects a pending external suspend
2283 // request. This is usually on transitions. It is also done in places
2284 // where continuing to the next transition would surprise the caller,
2285 // e.g., monitor entry.
2286 //
2287 // Returns the number of times that the thread self-suspended.
2288 //
2289 // Note: DO NOT call java_suspend_self() when you just want to block current
2290 // thread. java_suspend_self() is the second stage of cooperative
2291 // suspension for external suspend requests and should only be used
2292 // to complete an external suspend request.
2293 //
2294 int JavaThread::java_suspend_self() {
2295 int ret = 0;
2296
2297 // we are in the process of exiting so don't suspend
2298 if (is_exiting()) {
2299 clear_external_suspend();
2300 return ret;
2301 }
2302
2303 assert(_anchor.walkable() ||
2304 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2305 "must have walkable stack");
2306
2307 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2308
2309 assert(!this->is_ext_suspended(),
2310 "a thread trying to self-suspend should not already be suspended");
2311
2312 if (this->is_suspend_equivalent()) {
2313 // If we are self-suspending as a result of the lifting of a
2314 // suspend equivalent condition, then the suspend_equivalent
2315 // flag is not cleared until we set the ext_suspended flag so
2316 // that wait_for_ext_suspend_completion() returns consistent
2317 // results.
2318 this->clear_suspend_equivalent();
2319 }
2320
2321 // A racing resume may have cancelled us before we grabbed SR_lock
2322 // above. Or another external suspend request could be waiting for us
2323 // by the time we return from SR_lock()->wait(). The thread
2324 // that requested the suspension may already be trying to walk our
2325 // stack and if we return now, we can change the stack out from under
2326 // it. This would be a "bad thing (TM)" and cause the stack walker
2327 // to crash. We stay self-suspended until there are no more pending
2328 // external suspend requests.
2329 while (is_external_suspend()) {
2330 ret++;
2331 this->set_ext_suspended();
2332
2333 // _ext_suspended flag is cleared by java_resume()
2334 while (is_ext_suspended()) {
2335 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2336 }
2337 }
2338
2339 return ret;
2340 }
2341
2342 #ifdef ASSERT
2343 // verify the JavaThread has not yet been published in the Threads::list, and
2344 // hence doesn't need protection from concurrent access at this stage
2345 void JavaThread::verify_not_published() {
2346 if (!Threads_lock->owned_by_self()) {
2347 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2348 assert( !Threads::includes(this),
2349 "java thread shouldn't have been published yet!");
2350 }
2351 else {
2352 assert( !Threads::includes(this),
2353 "java thread shouldn't have been published yet!");
2354 }
2355 }
2356 #endif
2357
2358 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2359 // progress or when _suspend_flags is non-zero.
2360 // Current thread needs to self-suspend if there is a suspend request and/or
2361 // block if a safepoint is in progress.
2362 // Async exception ISN'T checked.
2363 // Note only the ThreadInVMfromNative transition can call this function
2364 // directly and when thread state is _thread_in_native_trans
2365 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2366 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2367
2368 JavaThread *curJT = JavaThread::current();
2369 bool do_self_suspend = thread->is_external_suspend();
2370
2371 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2372
2373 // If JNIEnv proxies are allowed, don't self-suspend if the target
2374 // thread is not the current thread. In older versions of jdbx, jdbx
2375 // threads could call into the VM with another thread's JNIEnv so we
2376 // can be here operating on behalf of a suspended thread (4432884).
2377 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2378 JavaThreadState state = thread->thread_state();
2379
2380 // We mark this thread_blocked state as a suspend-equivalent so
2381 // that a caller to is_ext_suspend_completed() won't be confused.
2382 // The suspend-equivalent state is cleared by java_suspend_self().
2383 thread->set_suspend_equivalent();
2384
2385 // If the safepoint code sees the _thread_in_native_trans state, it will
2386 // wait until the thread changes to other thread state. There is no
2387 // guarantee on how soon we can obtain the SR_lock and complete the
2388 // self-suspend request. It would be a bad idea to let safepoint wait for
2389 // too long. Temporarily change the state to _thread_blocked to
2390 // let the VM thread know that this thread is ready for GC. The problem
2391 // of changing thread state is that safepoint could happen just after
2392 // java_suspend_self() returns after being resumed, and VM thread will
2393 // see the _thread_blocked state. We must check for safepoint
2394 // after restoring the state and make sure we won't leave while a safepoint
2395 // is in progress.
2396 thread->set_thread_state(_thread_blocked);
2397 thread->java_suspend_self();
2398 thread->set_thread_state(state);
2399 // Make sure new state is seen by VM thread
2400 if (os::is_MP()) {
2401 if (UseMembar) {
2402 // Force a fence between the write above and read below
2403 OrderAccess::fence();
2404 } else {
2405 // Must use this rather than serialization page in particular on Windows
2406 InterfaceSupport::serialize_memory(thread);
2407 }
2408 }
2409 }
2410
2411 if (SafepointSynchronize::do_call_back()) {
2412 // If we are safepointing, then block the caller which may not be
2413 // the same as the target thread (see above).
2414 SafepointSynchronize::block(curJT);
2415 }
2416
2417 if (thread->is_deopt_suspend()) {
2418 thread->clear_deopt_suspend();
2419 RegisterMap map(thread, false);
2420 frame f = thread->last_frame();
2421 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2422 f = f.sender(&map);
2423 }
2424 if (f.id() == thread->must_deopt_id()) {
2425 thread->clear_must_deopt_id();
2426 f.deoptimize(thread);
2427 } else {
2428 fatal("missed deoptimization!");
2429 }
2430 }
2431 #if INCLUDE_TRACE
2432 if (thread->is_trace_suspend()) {
2433 TRACE_SUSPEND_THREAD(thread);
2434 }
2435 #endif
2436 }
2437
2438 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2439 // progress or when _suspend_flags is non-zero.
2440 // Current thread needs to self-suspend if there is a suspend request and/or
2441 // block if a safepoint is in progress.
2442 // Also check for pending async exception (not including unsafe access error).
2443 // Note only the native==>VM/Java barriers can call this function and when
2444 // thread state is _thread_in_native_trans.
2445 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2446 check_safepoint_and_suspend_for_native_trans(thread);
2447
2448 if (thread->has_async_exception()) {
2449 // We are in _thread_in_native_trans state, don't handle unsafe
2450 // access error since that may block.
2451 thread->check_and_handle_async_exceptions(false);
2452 }
2453 }
2454
2455 // This is a variant of the normal
2456 // check_special_condition_for_native_trans with slightly different
2457 // semantics for use by critical native wrappers. It does all the
2458 // normal checks but also performs the transition back into
2459 // thread_in_Java state. This is required so that critical natives
2460 // can potentially block and perform a GC if they are the last thread
2461 // exiting the GC_locker.
2462 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2463 check_special_condition_for_native_trans(thread);
2464
2465 // Finish the transition
2466 thread->set_thread_state(_thread_in_Java);
2467
2468 if (thread->do_critical_native_unlock()) {
2469 ThreadInVMfromJavaNoAsyncException tiv(thread);
2470 GC_locker::unlock_critical(thread);
2471 thread->clear_critical_native_unlock();
2472 }
2473 }
2474
2475 // We need to guarantee the Threads_lock here, since resumes are not
2476 // allowed during safepoint synchronization
2477 // Can only resume from an external suspension
2478 void JavaThread::java_resume() {
2479 assert_locked_or_safepoint(Threads_lock);
2480
2481 // Sanity check: thread is gone, has started exiting or the thread
2482 // was not externally suspended.
2483 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2484 return;
2485 }
2486
2487 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2488
2489 clear_external_suspend();
2490
2491 if (is_ext_suspended()) {
2492 clear_ext_suspended();
2493 SR_lock()->notify_all();
2494 }
2495 }
2496
2497 void JavaThread::create_stack_guard_pages() {
2498 if (!os::uses_stack_guard_pages() ||
2499 _stack_guard_state != stack_guard_unused ||
2500 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2501 if (TraceThreadEvents) {
2502 tty->print_cr("Stack guard page creation for thread "
2503 UINTX_FORMAT " disabled", os::current_thread_id());
2504 }
2505 return;
2506 }
2507 address low_addr = stack_base() - stack_size();
2508 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2509
2510 int allocate = os::allocate_stack_guard_pages();
2511 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2512
2513 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2514 warning("Attempt to allocate stack guard pages failed.");
2515 return;
2516 }
2517
2518 if (os::guard_memory((char *) low_addr, len)) {
2519 _stack_guard_state = stack_guard_enabled;
2520 } else {
2521 warning("Attempt to protect stack guard pages failed.");
2522 if (os::uncommit_memory((char *) low_addr, len)) {
2523 warning("Attempt to deallocate stack guard pages failed.");
2524 }
2525 }
2526 }
2527
2528 void JavaThread::remove_stack_guard_pages() {
2529 assert(Thread::current() == this, "from different thread");
2530 if (_stack_guard_state == stack_guard_unused) return;
2531 address low_addr = stack_base() - stack_size();
2532 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2533
2534 if (os::allocate_stack_guard_pages()) {
2535 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2536 _stack_guard_state = stack_guard_unused;
2537 } else {
2538 warning("Attempt to deallocate stack guard pages failed.");
2539 }
2540 } else {
2541 if (_stack_guard_state == stack_guard_unused) return;
2542 if (os::unguard_memory((char *) low_addr, len)) {
2543 _stack_guard_state = stack_guard_unused;
2544 } else {
2545 warning("Attempt to unprotect stack guard pages failed.");
2546 }
2547 }
2548 }
2549
2550 void JavaThread::enable_stack_yellow_zone() {
2551 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2552 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2553
2554 // The base notation is from the stacks point of view, growing downward.
2555 // We need to adjust it to work correctly with guard_memory()
2556 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2557
2558 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2559 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2560
2561 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2562 _stack_guard_state = stack_guard_enabled;
2563 } else {
2564 warning("Attempt to guard stack yellow zone failed.");
2565 }
2566 enable_register_stack_guard();
2567 }
2568
2569 void JavaThread::disable_stack_yellow_zone() {
2570 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2571 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2572
2573 // Simply return if called for a thread that does not use guard pages.
2574 if (_stack_guard_state == stack_guard_unused) return;
2575
2576 // The base notation is from the stacks point of view, growing downward.
2577 // We need to adjust it to work correctly with guard_memory()
2578 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2579
2580 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2581 _stack_guard_state = stack_guard_yellow_disabled;
2582 } else {
2583 warning("Attempt to unguard stack yellow zone failed.");
2584 }
2585 disable_register_stack_guard();
2586 }
2587
2588 void JavaThread::enable_stack_red_zone() {
2589 // The base notation is from the stacks point of view, growing downward.
2590 // We need to adjust it to work correctly with guard_memory()
2591 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2592 address base = stack_red_zone_base() - stack_red_zone_size();
2593
2594 guarantee(base < stack_base(),"Error calculating stack red zone");
2595 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2596
2597 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2598 warning("Attempt to guard stack red zone failed.");
2599 }
2600 }
2601
2602 void JavaThread::disable_stack_red_zone() {
2603 // The base notation is from the stacks point of view, growing downward.
2604 // We need to adjust it to work correctly with guard_memory()
2605 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2606 address base = stack_red_zone_base() - stack_red_zone_size();
2607 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2608 warning("Attempt to unguard stack red zone failed.");
2609 }
2610 }
2611
2612 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2613 // ignore is there is no stack
2614 if (!has_last_Java_frame()) return;
2615 // traverse the stack frames. Starts from top frame.
2616 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2617 frame* fr = fst.current();
2618 f(fr, fst.register_map());
2619 }
2620 }
2621
2622
2623 #ifndef PRODUCT
2624 // Deoptimization
2625 // Function for testing deoptimization
2626 void JavaThread::deoptimize() {
2627 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2628 StackFrameStream fst(this, UseBiasedLocking);
2629 bool deopt = false; // Dump stack only if a deopt actually happens.
2630 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2631 // Iterate over all frames in the thread and deoptimize
2632 for(; !fst.is_done(); fst.next()) {
2633 if(fst.current()->can_be_deoptimized()) {
2634
2635 if (only_at) {
2636 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2637 // consists of comma or carriage return separated numbers so
2638 // search for the current bci in that string.
2639 address pc = fst.current()->pc();
2640 nmethod* nm = (nmethod*) fst.current()->cb();
2641 ScopeDesc* sd = nm->scope_desc_at( pc);
2642 char buffer[8];
2643 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2644 size_t len = strlen(buffer);
2645 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2646 while (found != NULL) {
2647 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2648 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2649 // Check that the bci found is bracketed by terminators.
2650 break;
2651 }
2652 found = strstr(found + 1, buffer);
2653 }
2654 if (!found) {
2655 continue;
2656 }
2657 }
2658
2659 if (DebugDeoptimization && !deopt) {
2660 deopt = true; // One-time only print before deopt
2661 tty->print_cr("[BEFORE Deoptimization]");
2662 trace_frames();
2663 trace_stack();
2664 }
2665 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2666 }
2667 }
2668
2669 if (DebugDeoptimization && deopt) {
2670 tty->print_cr("[AFTER Deoptimization]");
2671 trace_frames();
2672 }
2673 }
2674
2675
2676 // Make zombies
2677 void JavaThread::make_zombies() {
2678 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2679 if (fst.current()->can_be_deoptimized()) {
2680 // it is a Java nmethod
2681 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2682 nm->make_not_entrant();
2683 }
2684 }
2685 }
2686 #endif // PRODUCT
2687
2688
2689 void JavaThread::deoptimized_wrt_marked_nmethods() {
2690 if (!has_last_Java_frame()) return;
2691 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2692 StackFrameStream fst(this, UseBiasedLocking);
2693 for(; !fst.is_done(); fst.next()) {
2694 if (fst.current()->should_be_deoptimized()) {
2695 if (LogCompilation && xtty != NULL) {
2696 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2697 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2698 this->name(), nm != NULL ? nm->compile_id() : -1);
2699 }
2700
2701 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2702 }
2703 }
2704 }
2705
2706
2707 // GC support
2708 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2709
2710 void JavaThread::gc_epilogue() {
2711 frames_do(frame_gc_epilogue);
2712 }
2713
2714
2715 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2716
2717 void JavaThread::gc_prologue() {
2718 frames_do(frame_gc_prologue);
2719 }
2720
2721 // If the caller is a NamedThread, then remember, in the current scope,
2722 // the given JavaThread in its _processed_thread field.
2723 class RememberProcessedThread: public StackObj {
2724 NamedThread* _cur_thr;
2725 public:
2726 RememberProcessedThread(JavaThread* jthr) {
2727 Thread* thread = Thread::current();
2728 if (thread->is_Named_thread()) {
2729 _cur_thr = (NamedThread *)thread;
2730 _cur_thr->set_processed_thread(jthr);
2731 } else {
2732 _cur_thr = NULL;
2733 }
2734 }
2735
2736 ~RememberProcessedThread() {
2737 if (_cur_thr) {
2738 _cur_thr->set_processed_thread(NULL);
2739 }
2740 }
2741 };
2742
2743 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2744 // Verify that the deferred card marks have been flushed.
2745 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2746
2747 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2748 // since there may be more than one thread using each ThreadProfiler.
2749
2750 // Traverse the GCHandles
2751 Thread::oops_do(f, cld_f, cf);
2752
2753 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2754 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2755
2756 if (has_last_Java_frame()) {
2757 // Record JavaThread to GC thread
2758 RememberProcessedThread rpt(this);
2759
2760 // Traverse the privileged stack
2761 if (_privileged_stack_top != NULL) {
2762 _privileged_stack_top->oops_do(f);
2763 }
2764
2765 // traverse the registered growable array
2766 if (_array_for_gc != NULL) {
2767 for (int index = 0; index < _array_for_gc->length(); index++) {
2768 f->do_oop(_array_for_gc->adr_at(index));
2769 }
2770 }
2771
2772 // Traverse the monitor chunks
2773 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2774 chunk->oops_do(f);
2775 }
2776
2777 // Traverse the execution stack
2778 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2779 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2780 }
2781 }
2782
2783 // callee_target is never live across a gc point so NULL it here should
2784 // it still contain a methdOop.
2785
2786 set_callee_target(NULL);
2787
2788 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2789 // If we have deferred set_locals there might be oops waiting to be
2790 // written
2791 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2792 if (list != NULL) {
2793 for (int i = 0; i < list->length(); i++) {
2794 list->at(i)->oops_do(f);
2795 }
2796 }
2797
2798 // Traverse instance variables at the end since the GC may be moving things
2799 // around using this function
2800 f->do_oop((oop*) &_threadObj);
2801 f->do_oop((oop*) &_vm_result);
2802 f->do_oop((oop*) &_exception_oop);
2803 f->do_oop((oop*) &_pending_async_exception);
2804
2805 if (jvmti_thread_state() != NULL) {
2806 jvmti_thread_state()->oops_do(f);
2807 }
2808 }
2809
2810 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2811 Thread::nmethods_do(cf); // (super method is a no-op)
2812
2813 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2814 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2815
2816 if (has_last_Java_frame()) {
2817 // Traverse the execution stack
2818 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2819 fst.current()->nmethods_do(cf);
2820 }
2821 }
2822 }
2823
2824 void JavaThread::metadata_do(void f(Metadata*)) {
2825 Thread::metadata_do(f);
2826 if (has_last_Java_frame()) {
2827 // Traverse the execution stack to call f() on the methods in the stack
2828 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2829 fst.current()->metadata_do(f);
2830 }
2831 } else if (is_Compiler_thread()) {
2832 // need to walk ciMetadata in current compile tasks to keep alive.
2833 CompilerThread* ct = (CompilerThread*)this;
2834 if (ct->env() != NULL) {
2835 ct->env()->metadata_do(f);
2836 }
2837 }
2838 }
2839
2840 // Printing
2841 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2842 switch (_thread_state) {
2843 case _thread_uninitialized: return "_thread_uninitialized";
2844 case _thread_new: return "_thread_new";
2845 case _thread_new_trans: return "_thread_new_trans";
2846 case _thread_in_native: return "_thread_in_native";
2847 case _thread_in_native_trans: return "_thread_in_native_trans";
2848 case _thread_in_vm: return "_thread_in_vm";
2849 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2850 case _thread_in_Java: return "_thread_in_Java";
2851 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2852 case _thread_blocked: return "_thread_blocked";
2853 case _thread_blocked_trans: return "_thread_blocked_trans";
2854 default: return "unknown thread state";
2855 }
2856 }
2857
2858 #ifndef PRODUCT
2859 void JavaThread::print_thread_state_on(outputStream *st) const {
2860 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2861 };
2862 void JavaThread::print_thread_state() const {
2863 print_thread_state_on(tty);
2864 };
2865 #endif // PRODUCT
2866
2867 // Called by Threads::print() for VM_PrintThreads operation
2868 void JavaThread::print_on(outputStream *st) const {
2869 st->print("\"%s\" ", get_thread_name());
2870 oop thread_oop = threadObj();
2871 if (thread_oop != NULL) {
2872 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2873 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2874 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2875 }
2876 Thread::print_on(st);
2877 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2878 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2879 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2880 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2881 }
2882 #ifndef PRODUCT
2883 print_thread_state_on(st);
2884 _safepoint_state->print_on(st);
2885 #endif // PRODUCT
2886 }
2887
2888 // Called by fatal error handler. The difference between this and
2889 // JavaThread::print() is that we can't grab lock or allocate memory.
2890 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2891 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2892 oop thread_obj = threadObj();
2893 if (thread_obj != NULL) {
2894 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2895 }
2896 st->print(" [");
2897 st->print("%s", _get_thread_state_name(_thread_state));
2898 if (osthread()) {
2899 st->print(", id=%d", osthread()->thread_id());
2900 }
2901 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2902 _stack_base - _stack_size, _stack_base);
2903 st->print("]");
2904 return;
2905 }
2906
2907 // Verification
2908
2909 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2910
2911 void JavaThread::verify() {
2912 // Verify oops in the thread.
2913 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2914
2915 // Verify the stack frames.
2916 frames_do(frame_verify);
2917 }
2918
2919 // CR 6300358 (sub-CR 2137150)
2920 // Most callers of this method assume that it can't return NULL but a
2921 // thread may not have a name whilst it is in the process of attaching to
2922 // the VM - see CR 6412693, and there are places where a JavaThread can be
2923 // seen prior to having it's threadObj set (eg JNI attaching threads and
2924 // if vm exit occurs during initialization). These cases can all be accounted
2925 // for such that this method never returns NULL.
2926 const char* JavaThread::get_thread_name() const {
2927 #ifdef ASSERT
2928 // early safepoints can hit while current thread does not yet have TLS
2929 if (!SafepointSynchronize::is_at_safepoint()) {
2930 Thread *cur = Thread::current();
2931 if (!(cur->is_Java_thread() && cur == this)) {
2932 // Current JavaThreads are allowed to get their own name without
2933 // the Threads_lock.
2934 assert_locked_or_safepoint(Threads_lock);
2935 }
2936 }
2937 #endif // ASSERT
2938 return get_thread_name_string();
2939 }
2940
2941 // Returns a non-NULL representation of this thread's name, or a suitable
2942 // descriptive string if there is no set name
2943 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2944 const char* name_str;
2945 oop thread_obj = threadObj();
2946 if (thread_obj != NULL) {
2947 oop name = java_lang_Thread::name(thread_obj);
2948 if (name != NULL) {
2949 if (buf == NULL) {
2950 name_str = java_lang_String::as_utf8_string(name);
2951 }
2952 else {
2953 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2954 }
2955 }
2956 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2957 name_str = "<no-name - thread is attaching>";
2958 }
2959 else {
2960 name_str = Thread::name();
2961 }
2962 }
2963 else {
2964 name_str = Thread::name();
2965 }
2966 assert(name_str != NULL, "unexpected NULL thread name");
2967 return name_str;
2968 }
2969
2970
2971 const char* JavaThread::get_threadgroup_name() const {
2972 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2973 oop thread_obj = threadObj();
2974 if (thread_obj != NULL) {
2975 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2976 if (thread_group != NULL) {
2977 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2978 // ThreadGroup.name can be null
2979 if (name != NULL) {
2980 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2981 return str;
2982 }
2983 }
2984 }
2985 return NULL;
2986 }
2987
2988 const char* JavaThread::get_parent_name() const {
2989 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2990 oop thread_obj = threadObj();
2991 if (thread_obj != NULL) {
2992 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2993 if (thread_group != NULL) {
2994 oop parent = java_lang_ThreadGroup::parent(thread_group);
2995 if (parent != NULL) {
2996 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2997 // ThreadGroup.name can be null
2998 if (name != NULL) {
2999 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
3000 return str;
3001 }
3002 }
3003 }
3004 }
3005 return NULL;
3006 }
3007
3008 ThreadPriority JavaThread::java_priority() const {
3009 oop thr_oop = threadObj();
3010 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3011 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3012 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3013 return priority;
3014 }
3015
3016 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3017
3018 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3019 // Link Java Thread object <-> C++ Thread
3020
3021 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3022 // and put it into a new Handle. The Handle "thread_oop" can then
3023 // be used to pass the C++ thread object to other methods.
3024
3025 // Set the Java level thread object (jthread) field of the
3026 // new thread (a JavaThread *) to C++ thread object using the
3027 // "thread_oop" handle.
3028
3029 // Set the thread field (a JavaThread *) of the
3030 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3031
3032 Handle thread_oop(Thread::current(),
3033 JNIHandles::resolve_non_null(jni_thread));
3034 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3035 "must be initialized");
3036 set_threadObj(thread_oop());
3037 java_lang_Thread::set_thread(thread_oop(), this);
3038
3039 if (prio == NoPriority) {
3040 prio = java_lang_Thread::priority(thread_oop());
3041 assert(prio != NoPriority, "A valid priority should be present");
3042 }
3043
3044 // Push the Java priority down to the native thread; needs Threads_lock
3045 Thread::set_priority(this, prio);
3046
3047 prepare_ext();
3048
3049 // Add the new thread to the Threads list and set it in motion.
3050 // We must have threads lock in order to call Threads::add.
3051 // It is crucial that we do not block before the thread is
3052 // added to the Threads list for if a GC happens, then the java_thread oop
3053 // will not be visited by GC.
3054 Threads::add(this);
3055 }
3056
3057 oop JavaThread::current_park_blocker() {
3058 // Support for JSR-166 locks
3059 oop thread_oop = threadObj();
3060 if (thread_oop != NULL &&
3061 JDK_Version::current().supports_thread_park_blocker()) {
3062 return java_lang_Thread::park_blocker(thread_oop);
3063 }
3064 return NULL;
3065 }
3066
3067
3068 void JavaThread::print_stack_on(outputStream* st) {
3069 if (!has_last_Java_frame()) return;
3070 ResourceMark rm;
3071 HandleMark hm;
3072
3073 RegisterMap reg_map(this);
3074 vframe* start_vf = last_java_vframe(®_map);
3075 int count = 0;
3076 for (vframe* f = start_vf; f; f = f->sender() ) {
3077 if (f->is_java_frame()) {
3078 javaVFrame* jvf = javaVFrame::cast(f);
3079 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3080
3081 // Print out lock information
3082 if (JavaMonitorsInStackTrace) {
3083 jvf->print_lock_info_on(st, count);
3084 }
3085 } else {
3086 // Ignore non-Java frames
3087 }
3088
3089 // Bail-out case for too deep stacks
3090 count++;
3091 if (MaxJavaStackTraceDepth == count) return;
3092 }
3093 }
3094
3095
3096 // JVMTI PopFrame support
3097 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3098 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3099 if (in_bytes(size_in_bytes) != 0) {
3100 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3101 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3102 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3103 }
3104 }
3105
3106 void* JavaThread::popframe_preserved_args() {
3107 return _popframe_preserved_args;
3108 }
3109
3110 ByteSize JavaThread::popframe_preserved_args_size() {
3111 return in_ByteSize(_popframe_preserved_args_size);
3112 }
3113
3114 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3115 int sz = in_bytes(popframe_preserved_args_size());
3116 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3117 return in_WordSize(sz / wordSize);
3118 }
3119
3120 void JavaThread::popframe_free_preserved_args() {
3121 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3122 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3123 _popframe_preserved_args = NULL;
3124 _popframe_preserved_args_size = 0;
3125 }
3126
3127 #ifndef PRODUCT
3128
3129 void JavaThread::trace_frames() {
3130 tty->print_cr("[Describe stack]");
3131 int frame_no = 1;
3132 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3133 tty->print(" %d. ", frame_no++);
3134 fst.current()->print_value_on(tty,this);
3135 tty->cr();
3136 }
3137 }
3138
3139 class PrintAndVerifyOopClosure: public OopClosure {
3140 protected:
3141 template <class T> inline void do_oop_work(T* p) {
3142 oop obj = oopDesc::load_decode_heap_oop(p);
3143 if (obj == NULL) return;
3144 tty->print(INTPTR_FORMAT ": ", p);
3145 if (obj->is_oop_or_null()) {
3146 if (obj->is_objArray()) {
3147 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3148 } else {
3149 obj->print();
3150 }
3151 } else {
3152 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3153 }
3154 tty->cr();
3155 }
3156 public:
3157 virtual void do_oop(oop* p) { do_oop_work(p); }
3158 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3159 };
3160
3161
3162 static void oops_print(frame* f, const RegisterMap *map) {
3163 PrintAndVerifyOopClosure print;
3164 f->print_value();
3165 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3166 }
3167
3168 // Print our all the locations that contain oops and whether they are
3169 // valid or not. This useful when trying to find the oldest frame
3170 // where an oop has gone bad since the frame walk is from youngest to
3171 // oldest.
3172 void JavaThread::trace_oops() {
3173 tty->print_cr("[Trace oops]");
3174 frames_do(oops_print);
3175 }
3176
3177
3178 #ifdef ASSERT
3179 // Print or validate the layout of stack frames
3180 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3181 ResourceMark rm;
3182 PRESERVE_EXCEPTION_MARK;
3183 FrameValues values;
3184 int frame_no = 0;
3185 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3186 fst.current()->describe(values, ++frame_no);
3187 if (depth == frame_no) break;
3188 }
3189 if (validate_only) {
3190 values.validate();
3191 } else {
3192 tty->print_cr("[Describe stack layout]");
3193 values.print(this);
3194 }
3195 }
3196 #endif
3197
3198 void JavaThread::trace_stack_from(vframe* start_vf) {
3199 ResourceMark rm;
3200 int vframe_no = 1;
3201 for (vframe* f = start_vf; f; f = f->sender() ) {
3202 if (f->is_java_frame()) {
3203 javaVFrame::cast(f)->print_activation(vframe_no++);
3204 } else {
3205 f->print();
3206 }
3207 if (vframe_no > StackPrintLimit) {
3208 tty->print_cr("...<more frames>...");
3209 return;
3210 }
3211 }
3212 }
3213
3214
3215 void JavaThread::trace_stack() {
3216 if (!has_last_Java_frame()) return;
3217 ResourceMark rm;
3218 HandleMark hm;
3219 RegisterMap reg_map(this);
3220 trace_stack_from(last_java_vframe(®_map));
3221 }
3222
3223
3224 #endif // PRODUCT
3225
3226
3227 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3228 assert(reg_map != NULL, "a map must be given");
3229 frame f = last_frame();
3230 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3231 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3232 }
3233 return NULL;
3234 }
3235
3236
3237 Klass* JavaThread::security_get_caller_class(int depth) {
3238 vframeStream vfst(this);
3239 vfst.security_get_caller_frame(depth);
3240 if (!vfst.at_end()) {
3241 return vfst.method()->method_holder();
3242 }
3243 return NULL;
3244 }
3245
3246 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3247 assert(thread->is_Compiler_thread(), "must be compiler thread");
3248 CompileBroker::compiler_thread_loop();
3249 }
3250
3251 // Create a CompilerThread
3252 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3253 : JavaThread(&compiler_thread_entry) {
3254 _env = NULL;
3255 _log = NULL;
3256 _task = NULL;
3257 _queue = queue;
3258 _counters = counters;
3259 _buffer_blob = NULL;
3260 _scanned_nmethod = NULL;
3261 _compiler = NULL;
3262
3263 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3264 resource_area()->bias_to(mtCompiler);
3265
3266 #ifndef PRODUCT
3267 _ideal_graph_printer = NULL;
3268 #endif
3269 }
3270
3271 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3272 JavaThread::oops_do(f, cld_f, cf);
3273 if (_scanned_nmethod != NULL && cf != NULL) {
3274 // Safepoints can occur when the sweeper is scanning an nmethod so
3275 // process it here to make sure it isn't unloaded in the middle of
3276 // a scan.
3277 cf->do_code_blob(_scanned_nmethod);
3278 }
3279 }
3280
3281
3282 // ======= Threads ========
3283
3284 // The Threads class links together all active threads, and provides
3285 // operations over all threads. It is protected by its own Mutex
3286 // lock, which is also used in other contexts to protect thread
3287 // operations from having the thread being operated on from exiting
3288 // and going away unexpectedly (e.g., safepoint synchronization)
3289
3290 JavaThread* Threads::_thread_list = NULL;
3291 int Threads::_number_of_threads = 0;
3292 int Threads::_number_of_non_daemon_threads = 0;
3293 int Threads::_return_code = 0;
3294 size_t JavaThread::_stack_size_at_create = 0;
3295 #ifdef ASSERT
3296 bool Threads::_vm_complete = false;
3297 #endif
3298
3299 // All JavaThreads
3300 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3301
3302 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3303 void Threads::threads_do(ThreadClosure* tc) {
3304 assert_locked_or_safepoint(Threads_lock);
3305 // ALL_JAVA_THREADS iterates through all JavaThreads
3306 ALL_JAVA_THREADS(p) {
3307 tc->do_thread(p);
3308 }
3309 // Someday we could have a table or list of all non-JavaThreads.
3310 // For now, just manually iterate through them.
3311 tc->do_thread(VMThread::vm_thread());
3312 Universe::heap()->gc_threads_do(tc);
3313 WatcherThread *wt = WatcherThread::watcher_thread();
3314 // Strictly speaking, the following NULL check isn't sufficient to make sure
3315 // the data for WatcherThread is still valid upon being examined. However,
3316 // considering that WatchThread terminates when the VM is on the way to
3317 // exit at safepoint, the chance of the above is extremely small. The right
3318 // way to prevent termination of WatcherThread would be to acquire
3319 // Terminator_lock, but we can't do that without violating the lock rank
3320 // checking in some cases.
3321 if (wt != NULL)
3322 tc->do_thread(wt);
3323
3324 // If CompilerThreads ever become non-JavaThreads, add them here
3325 }
3326
3327 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3328
3329 extern void JDK_Version_init();
3330
3331 // Preinitialize version info.
3332 VM_Version::early_initialize();
3333
3334 // Check version
3335 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3336
3337 // Initialize the output stream module
3338 ostream_init();
3339
3340 // Process java launcher properties.
3341 Arguments::process_sun_java_launcher_properties(args);
3342
3343 // Initialize the os module before using TLS
3344 os::init();
3345
3346 // Initialize system properties.
3347 Arguments::init_system_properties();
3348
3349 // So that JDK version can be used as a discrimintor when parsing arguments
3350 JDK_Version_init();
3351
3352 // Update/Initialize System properties after JDK version number is known
3353 Arguments::init_version_specific_system_properties();
3354
3355 // Parse arguments
3356 // Note: this internally calls os::init_container_support()
3357 jint parse_result = Arguments::parse(args);
3358 if (parse_result != JNI_OK) return parse_result;
3359
3360 os::init_before_ergo();
3361
3362 jint ergo_result = Arguments::apply_ergo();
3363 if (ergo_result != JNI_OK) return ergo_result;
3364
3365 if (PauseAtStartup) {
3366 os::pause();
3367 }
3368
3369 #ifndef USDT2
3370 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3371 #else /* USDT2 */
3372 HOTSPOT_VM_INIT_BEGIN();
3373 #endif /* USDT2 */
3374
3375 // Record VM creation timing statistics
3376 TraceVmCreationTime create_vm_timer;
3377 create_vm_timer.start();
3378
3379 // Timing (must come after argument parsing)
3380 TraceTime timer("Create VM", TraceStartupTime);
3381
3382 // Initialize the os module after parsing the args
3383 jint os_init_2_result = os::init_2();
3384 if (os_init_2_result != JNI_OK) return os_init_2_result;
3385
3386 jint adjust_after_os_result = Arguments::adjust_after_os();
3387 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3388
3389 // intialize TLS
3390 ThreadLocalStorage::init();
3391
3392 // Initialize output stream logging
3393 ostream_init_log();
3394
3395 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3396 // Must be before create_vm_init_agents()
3397 if (Arguments::init_libraries_at_startup()) {
3398 convert_vm_init_libraries_to_agents();
3399 }
3400
3401 // Launch -agentlib/-agentpath and converted -Xrun agents
3402 if (Arguments::init_agents_at_startup()) {
3403 create_vm_init_agents();
3404 }
3405
3406 // Initialize Threads state
3407 _thread_list = NULL;
3408 _number_of_threads = 0;
3409 _number_of_non_daemon_threads = 0;
3410
3411 // Initialize global data structures and create system classes in heap
3412 vm_init_globals();
3413
3414 // Attach the main thread to this os thread
3415 JavaThread* main_thread = new JavaThread();
3416 main_thread->set_thread_state(_thread_in_vm);
3417 // must do this before set_active_handles and initialize_thread_local_storage
3418 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3419 // change the stack size recorded here to one based on the java thread
3420 // stacksize. This adjusted size is what is used to figure the placement
3421 // of the guard pages.
3422 main_thread->record_stack_base_and_size();
3423 main_thread->initialize_thread_local_storage();
3424
3425 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3426
3427 if (!main_thread->set_as_starting_thread()) {
3428 vm_shutdown_during_initialization(
3429 "Failed necessary internal allocation. Out of swap space");
3430 delete main_thread;
3431 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3432 return JNI_ENOMEM;
3433 }
3434
3435 // Enable guard page *after* os::create_main_thread(), otherwise it would
3436 // crash Linux VM, see notes in os_linux.cpp.
3437 main_thread->create_stack_guard_pages();
3438
3439 // Initialize Java-Level synchronization subsystem
3440 ObjectMonitor::Initialize() ;
3441
3442 // Initialize global modules
3443 jint status = init_globals();
3444 if (status != JNI_OK) {
3445 delete main_thread;
3446 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3447 return status;
3448 }
3449
3450 // Should be done after the heap is fully created
3451 main_thread->cache_global_variables();
3452
3453 HandleMark hm;
3454
3455 { MutexLocker mu(Threads_lock);
3456 Threads::add(main_thread);
3457 }
3458
3459 // Any JVMTI raw monitors entered in onload will transition into
3460 // real raw monitor. VM is setup enough here for raw monitor enter.
3461 JvmtiExport::transition_pending_onload_raw_monitors();
3462
3463 // Create the VMThread
3464 { TraceTime timer("Start VMThread", TraceStartupTime);
3465 VMThread::create();
3466 Thread* vmthread = VMThread::vm_thread();
3467
3468 if (!os::create_thread(vmthread, os::vm_thread))
3469 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3470
3471 // Wait for the VM thread to become ready, and VMThread::run to initialize
3472 // Monitors can have spurious returns, must always check another state flag
3473 {
3474 MutexLocker ml(Notify_lock);
3475 os::start_thread(vmthread);
3476 while (vmthread->active_handles() == NULL) {
3477 Notify_lock->wait();
3478 }
3479 }
3480 }
3481
3482 assert (Universe::is_fully_initialized(), "not initialized");
3483 if (VerifyDuringStartup) {
3484 // Make sure we're starting with a clean slate.
3485 VM_Verify verify_op;
3486 VMThread::execute(&verify_op);
3487 }
3488
3489 EXCEPTION_MARK;
3490
3491 // At this point, the Universe is initialized, but we have not executed
3492 // any byte code. Now is a good time (the only time) to dump out the
3493 // internal state of the JVM for sharing.
3494 if (DumpSharedSpaces) {
3495 MetaspaceShared::preload_and_dump(CHECK_0);
3496 ShouldNotReachHere();
3497 }
3498
3499 // Always call even when there are not JVMTI environments yet, since environments
3500 // may be attached late and JVMTI must track phases of VM execution
3501 JvmtiExport::enter_start_phase();
3502
3503 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3504 JvmtiExport::post_vm_start();
3505
3506 {
3507 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3508
3509 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3510 create_vm_init_libraries();
3511 }
3512
3513 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3514
3515 // Initialize java_lang.System (needed before creating the thread)
3516 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3517 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3518 Handle thread_group = create_initial_thread_group(CHECK_0);
3519 Universe::set_main_thread_group(thread_group());
3520 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3521 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3522 main_thread->set_threadObj(thread_object);
3523 // Set thread status to running since main thread has
3524 // been started and running.
3525 java_lang_Thread::set_thread_status(thread_object,
3526 java_lang_Thread::RUNNABLE);
3527
3528 // The VM creates & returns objects of this class. Make sure it's initialized.
3529 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3530
3531 // The VM preresolves methods to these classes. Make sure that they get initialized
3532 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3533 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3534 call_initializeSystemClass(CHECK_0);
3535
3536 // get the Java runtime name after java.lang.System is initialized
3537 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3538 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3539
3540 // an instance of OutOfMemory exception has been allocated earlier
3541 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3542 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3543 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3544 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3545 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3546 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3547 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3548 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3549 }
3550
3551 // See : bugid 4211085.
3552 // Background : the static initializer of java.lang.Compiler tries to read
3553 // property"java.compiler" and read & write property "java.vm.info".
3554 // When a security manager is installed through the command line
3555 // option "-Djava.security.manager", the above properties are not
3556 // readable and the static initializer for java.lang.Compiler fails
3557 // resulting in a NoClassDefFoundError. This can happen in any
3558 // user code which calls methods in java.lang.Compiler.
3559 // Hack : the hack is to pre-load and initialize this class, so that only
3560 // system domains are on the stack when the properties are read.
3561 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3562 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3563 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3564 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3565 // Once that is done, we should remove this hack.
3566 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3567
3568 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3569 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3570 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3571 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3572 // This should also be taken out as soon as 4211383 gets fixed.
3573 reset_vm_info_property(CHECK_0);
3574
3575 quicken_jni_functions();
3576
3577 // Must be run after init_ft which initializes ft_enabled
3578 if (TRACE_INITIALIZE() != JNI_OK) {
3579 vm_exit_during_initialization("Failed to initialize tracing backend");
3580 }
3581
3582 // Set flag that basic initialization has completed. Used by exceptions and various
3583 // debug stuff, that does not work until all basic classes have been initialized.
3584 set_init_completed();
3585
3586 Metaspace::post_initialize();
3587
3588 #ifndef USDT2
3589 HS_DTRACE_PROBE(hotspot, vm__init__end);
3590 #else /* USDT2 */
3591 HOTSPOT_VM_INIT_END();
3592 #endif /* USDT2 */
3593
3594 // record VM initialization completion time
3595 #if INCLUDE_MANAGEMENT
3596 Management::record_vm_init_completed();
3597 #endif // INCLUDE_MANAGEMENT
3598
3599 // Compute system loader. Note that this has to occur after set_init_completed, since
3600 // valid exceptions may be thrown in the process.
3601 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3602 // set_init_completed has just been called, causing exceptions not to be shortcut
3603 // anymore. We call vm_exit_during_initialization directly instead.
3604 SystemDictionary::compute_java_system_loader(THREAD);
3605 if (HAS_PENDING_EXCEPTION) {
3606 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3607 }
3608
3609 #if INCLUDE_ALL_GCS
3610 // Support for ConcurrentMarkSweep. This should be cleaned up
3611 // and better encapsulated. The ugly nested if test would go away
3612 // once things are properly refactored. XXX YSR
3613 if (UseConcMarkSweepGC || UseG1GC) {
3614 if (UseConcMarkSweepGC) {
3615 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3616 } else {
3617 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3618 }
3619 if (HAS_PENDING_EXCEPTION) {
3620 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3621 }
3622 }
3623 #endif // INCLUDE_ALL_GCS
3624
3625 // Always call even when there are not JVMTI environments yet, since environments
3626 // may be attached late and JVMTI must track phases of VM execution
3627 JvmtiExport::enter_live_phase();
3628
3629 // Signal Dispatcher needs to be started before VMInit event is posted
3630 os::signal_init();
3631
3632 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3633 if (!DisableAttachMechanism) {
3634 AttachListener::vm_start();
3635 if (StartAttachListener || AttachListener::init_at_startup()) {
3636 AttachListener::init();
3637 }
3638 }
3639
3640 // Launch -Xrun agents
3641 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3642 // back-end can launch with -Xdebug -Xrunjdwp.
3643 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3644 create_vm_init_libraries();
3645 }
3646
3647 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3648 JvmtiExport::post_vm_initialized();
3649
3650 if (TRACE_START() != JNI_OK) {
3651 vm_exit_during_initialization("Failed to start tracing backend.");
3652 }
3653
3654 if (CleanChunkPoolAsync) {
3655 Chunk::start_chunk_pool_cleaner_task();
3656 }
3657
3658 // initialize compiler(s)
3659 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3660 CompileBroker::compilation_init();
3661 #endif
3662
3663 if (EnableInvokeDynamic) {
3664 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3665 // It is done after compilers are initialized, because otherwise compilations of
3666 // signature polymorphic MH intrinsics can be missed
3667 // (see SystemDictionary::find_method_handle_intrinsic).
3668 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3669 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3670 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3671 }
3672
3673 #if INCLUDE_MANAGEMENT
3674 Management::initialize(THREAD);
3675 #endif // INCLUDE_MANAGEMENT
3676
3677 if (HAS_PENDING_EXCEPTION) {
3678 // management agent fails to start possibly due to
3679 // configuration problem and is responsible for printing
3680 // stack trace if appropriate. Simply exit VM.
3681 vm_exit(1);
3682 }
3683
3684 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3685 if (MemProfiling) MemProfiler::engage();
3686 StatSampler::engage();
3687 if (CheckJNICalls) JniPeriodicChecker::engage();
3688
3689 BiasedLocking::init();
3690
3691 #if INCLUDE_RTM_OPT
3692 RTMLockingCounters::init();
3693 #endif
3694
3695 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3696 call_postVMInitHook(THREAD);
3697 // The Java side of PostVMInitHook.run must deal with all
3698 // exceptions and provide means of diagnosis.
3699 if (HAS_PENDING_EXCEPTION) {
3700 CLEAR_PENDING_EXCEPTION;
3701 }
3702 }
3703
3704 {
3705 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3706 // Make sure the watcher thread can be started by WatcherThread::start()
3707 // or by dynamic enrollment.
3708 WatcherThread::make_startable();
3709 // Start up the WatcherThread if there are any periodic tasks
3710 // NOTE: All PeriodicTasks should be registered by now. If they
3711 // aren't, late joiners might appear to start slowly (we might
3712 // take a while to process their first tick).
3713 if (PeriodicTask::num_tasks() > 0) {
3714 WatcherThread::start();
3715 }
3716 }
3717
3718 create_vm_timer.end();
3719 #ifdef ASSERT
3720 _vm_complete = true;
3721 #endif
3722 return JNI_OK;
3723 }
3724
3725 // type for the Agent_OnLoad and JVM_OnLoad entry points
3726 extern "C" {
3727 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3728 }
3729 // Find a command line agent library and return its entry point for
3730 // -agentlib: -agentpath: -Xrun
3731 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3732 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3733 OnLoadEntry_t on_load_entry = NULL;
3734 void *library = NULL;
3735
3736 if (!agent->valid()) {
3737 char buffer[JVM_MAXPATHLEN];
3738 char ebuf[1024];
3739 const char *name = agent->name();
3740 const char *msg = "Could not find agent library ";
3741
3742 // First check to see if agent is statically linked into executable
3743 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3744 library = agent->os_lib();
3745 } else if (agent->is_absolute_path()) {
3746 library = os::dll_load(name, ebuf, sizeof ebuf);
3747 if (library == NULL) {
3748 const char *sub_msg = " in absolute path, with error: ";
3749 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3750 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3751 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3752 // If we can't find the agent, exit.
3753 vm_exit_during_initialization(buf, NULL);
3754 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3755 }
3756 } else {
3757 // Try to load the agent from the standard dll directory
3758 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3759 name)) {
3760 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3761 }
3762 if (library == NULL) { // Try the local directory
3763 char ns[1] = {0};
3764 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3765 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3766 }
3767 if (library == NULL) {
3768 const char *sub_msg = " on the library path, with error: ";
3769 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3770 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3771 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3772 // If we can't find the agent, exit.
3773 vm_exit_during_initialization(buf, NULL);
3774 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3775 }
3776 }
3777 }
3778 agent->set_os_lib(library);
3779 agent->set_valid();
3780 }
3781
3782 // Find the OnLoad function.
3783 on_load_entry =
3784 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3785 false,
3786 on_load_symbols,
3787 num_symbol_entries));
3788 return on_load_entry;
3789 }
3790
3791 // Find the JVM_OnLoad entry point
3792 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3793 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3794 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3795 }
3796
3797 // Find the Agent_OnLoad entry point
3798 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3799 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3800 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3801 }
3802
3803 // For backwards compatibility with -Xrun
3804 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3805 // treated like -agentpath:
3806 // Must be called before agent libraries are created
3807 void Threads::convert_vm_init_libraries_to_agents() {
3808 AgentLibrary* agent;
3809 AgentLibrary* next;
3810
3811 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3812 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3813 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3814
3815 // If there is an JVM_OnLoad function it will get called later,
3816 // otherwise see if there is an Agent_OnLoad
3817 if (on_load_entry == NULL) {
3818 on_load_entry = lookup_agent_on_load(agent);
3819 if (on_load_entry != NULL) {
3820 // switch it to the agent list -- so that Agent_OnLoad will be called,
3821 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3822 Arguments::convert_library_to_agent(agent);
3823 } else {
3824 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3825 }
3826 }
3827 }
3828 }
3829
3830 // Create agents for -agentlib: -agentpath: and converted -Xrun
3831 // Invokes Agent_OnLoad
3832 // Called very early -- before JavaThreads exist
3833 void Threads::create_vm_init_agents() {
3834 extern struct JavaVM_ main_vm;
3835 AgentLibrary* agent;
3836
3837 JvmtiExport::enter_onload_phase();
3838
3839 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3840 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3841
3842 if (on_load_entry != NULL) {
3843 // Invoke the Agent_OnLoad function
3844 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3845 if (err != JNI_OK) {
3846 vm_exit_during_initialization("agent library failed to init", agent->name());
3847 }
3848 } else {
3849 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3850 }
3851 }
3852 JvmtiExport::enter_primordial_phase();
3853 }
3854
3855 extern "C" {
3856 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3857 }
3858
3859 void Threads::shutdown_vm_agents() {
3860 // Send any Agent_OnUnload notifications
3861 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3862 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3863 extern struct JavaVM_ main_vm;
3864 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3865
3866 // Find the Agent_OnUnload function.
3867 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3868 os::find_agent_function(agent,
3869 false,
3870 on_unload_symbols,
3871 num_symbol_entries));
3872
3873 // Invoke the Agent_OnUnload function
3874 if (unload_entry != NULL) {
3875 JavaThread* thread = JavaThread::current();
3876 ThreadToNativeFromVM ttn(thread);
3877 HandleMark hm(thread);
3878 (*unload_entry)(&main_vm);
3879 }
3880 }
3881 }
3882
3883 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3884 // Invokes JVM_OnLoad
3885 void Threads::create_vm_init_libraries() {
3886 extern struct JavaVM_ main_vm;
3887 AgentLibrary* agent;
3888
3889 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3890 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3891
3892 if (on_load_entry != NULL) {
3893 // Invoke the JVM_OnLoad function
3894 JavaThread* thread = JavaThread::current();
3895 ThreadToNativeFromVM ttn(thread);
3896 HandleMark hm(thread);
3897 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3898 if (err != JNI_OK) {
3899 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3900 }
3901 } else {
3902 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3903 }
3904 }
3905 }
3906
3907 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3908 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3909
3910 JavaThread* java_thread = NULL;
3911 // Sequential search for now. Need to do better optimization later.
3912 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3913 oop tobj = thread->threadObj();
3914 if (!thread->is_exiting() &&
3915 tobj != NULL &&
3916 java_tid == java_lang_Thread::thread_id(tobj)) {
3917 java_thread = thread;
3918 break;
3919 }
3920 }
3921 return java_thread;
3922 }
3923
3924
3925 // Last thread running calls java.lang.Shutdown.shutdown()
3926 void JavaThread::invoke_shutdown_hooks() {
3927 HandleMark hm(this);
3928
3929 // We could get here with a pending exception, if so clear it now.
3930 if (this->has_pending_exception()) {
3931 this->clear_pending_exception();
3932 }
3933
3934 EXCEPTION_MARK;
3935 Klass* k =
3936 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3937 THREAD);
3938 if (k != NULL) {
3939 // SystemDictionary::resolve_or_null will return null if there was
3940 // an exception. If we cannot load the Shutdown class, just don't
3941 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3942 // and finalizers (if runFinalizersOnExit is set) won't be run.
3943 // Note that if a shutdown hook was registered or runFinalizersOnExit
3944 // was called, the Shutdown class would have already been loaded
3945 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3946 instanceKlassHandle shutdown_klass (THREAD, k);
3947 JavaValue result(T_VOID);
3948 JavaCalls::call_static(&result,
3949 shutdown_klass,
3950 vmSymbols::shutdown_method_name(),
3951 vmSymbols::void_method_signature(),
3952 THREAD);
3953 }
3954 CLEAR_PENDING_EXCEPTION;
3955 }
3956
3957 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3958 // the program falls off the end of main(). Another VM exit path is through
3959 // vm_exit() when the program calls System.exit() to return a value or when
3960 // there is a serious error in VM. The two shutdown paths are not exactly
3961 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3962 // and VM_Exit op at VM level.
3963 //
3964 // Shutdown sequence:
3965 // + Shutdown native memory tracking if it is on
3966 // + Wait until we are the last non-daemon thread to execute
3967 // <-- every thing is still working at this moment -->
3968 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3969 // shutdown hooks, run finalizers if finalization-on-exit
3970 // + Call before_exit(), prepare for VM exit
3971 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3972 // currently the only user of this mechanism is File.deleteOnExit())
3973 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3974 // post thread end and vm death events to JVMTI,
3975 // stop signal thread
3976 // + Call JavaThread::exit(), it will:
3977 // > release JNI handle blocks, remove stack guard pages
3978 // > remove this thread from Threads list
3979 // <-- no more Java code from this thread after this point -->
3980 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3981 // the compiler threads at safepoint
3982 // <-- do not use anything that could get blocked by Safepoint -->
3983 // + Disable tracing at JNI/JVM barriers
3984 // + Set _vm_exited flag for threads that are still running native code
3985 // + Delete this thread
3986 // + Call exit_globals()
3987 // > deletes tty
3988 // > deletes PerfMemory resources
3989 // + Return to caller
3990
3991 bool Threads::destroy_vm() {
3992 JavaThread* thread = JavaThread::current();
3993
3994 #ifdef ASSERT
3995 _vm_complete = false;
3996 #endif
3997 // Wait until we are the last non-daemon thread to execute
3998 { MutexLocker nu(Threads_lock);
3999 while (Threads::number_of_non_daemon_threads() > 1 )
4000 // This wait should make safepoint checks, wait without a timeout,
4001 // and wait as a suspend-equivalent condition.
4002 //
4003 // Note: If the FlatProfiler is running and this thread is waiting
4004 // for another non-daemon thread to finish, then the FlatProfiler
4005 // is waiting for the external suspend request on this thread to
4006 // complete. wait_for_ext_suspend_completion() will eventually
4007 // timeout, but that takes time. Making this wait a suspend-
4008 // equivalent condition solves that timeout problem.
4009 //
4010 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4011 Mutex::_as_suspend_equivalent_flag);
4012 }
4013
4014 // Hang forever on exit if we are reporting an error.
4015 if (ShowMessageBoxOnError && is_error_reported()) {
4016 os::infinite_sleep();
4017 }
4018 os::wait_for_keypress_at_exit();
4019
4020 if (JDK_Version::is_jdk12x_version()) {
4021 // We are the last thread running, so check if finalizers should be run.
4022 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4023 HandleMark rm(thread);
4024 Universe::run_finalizers_on_exit();
4025 } else {
4026 // run Java level shutdown hooks
4027 thread->invoke_shutdown_hooks();
4028 }
4029
4030 before_exit(thread);
4031
4032 thread->exit(true);
4033
4034 // Stop VM thread.
4035 {
4036 // 4945125 The vm thread comes to a safepoint during exit.
4037 // GC vm_operations can get caught at the safepoint, and the
4038 // heap is unparseable if they are caught. Grab the Heap_lock
4039 // to prevent this. The GC vm_operations will not be able to
4040 // queue until after the vm thread is dead. After this point,
4041 // we'll never emerge out of the safepoint before the VM exits.
4042
4043 MutexLocker ml(Heap_lock);
4044
4045 VMThread::wait_for_vm_thread_exit();
4046 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4047 VMThread::destroy();
4048 }
4049
4050 // clean up ideal graph printers
4051 #if defined(COMPILER2) && !defined(PRODUCT)
4052 IdealGraphPrinter::clean_up();
4053 #endif
4054
4055 // Now, all Java threads are gone except daemon threads. Daemon threads
4056 // running Java code or in VM are stopped by the Safepoint. However,
4057 // daemon threads executing native code are still running. But they
4058 // will be stopped at native=>Java/VM barriers. Note that we can't
4059 // simply kill or suspend them, as it is inherently deadlock-prone.
4060
4061 #ifndef PRODUCT
4062 // disable function tracing at JNI/JVM barriers
4063 TraceJNICalls = false;
4064 TraceJVMCalls = false;
4065 TraceRuntimeCalls = false;
4066 #endif
4067
4068 VM_Exit::set_vm_exited();
4069
4070 notify_vm_shutdown();
4071
4072 delete thread;
4073
4074 // exit_globals() will delete tty
4075 exit_globals();
4076
4077 return true;
4078 }
4079
4080
4081 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4082 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4083 return is_supported_jni_version(version);
4084 }
4085
4086
4087 jboolean Threads::is_supported_jni_version(jint version) {
4088 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4089 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4090 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4091 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4092 return JNI_FALSE;
4093 }
4094
4095
4096 void Threads::add(JavaThread* p, bool force_daemon) {
4097 // The threads lock must be owned at this point
4098 assert_locked_or_safepoint(Threads_lock);
4099
4100 // See the comment for this method in thread.hpp for its purpose and
4101 // why it is called here.
4102 p->initialize_queues();
4103 p->set_next(_thread_list);
4104 _thread_list = p;
4105 _number_of_threads++;
4106 oop threadObj = p->threadObj();
4107 bool daemon = true;
4108 // Bootstrapping problem: threadObj can be null for initial
4109 // JavaThread (or for threads attached via JNI)
4110 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4111 _number_of_non_daemon_threads++;
4112 daemon = false;
4113 }
4114
4115 ThreadService::add_thread(p, daemon);
4116
4117 // Possible GC point.
4118 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4119 }
4120
4121 void Threads::remove(JavaThread* p) {
4122 // Extra scope needed for Thread_lock, so we can check
4123 // that we do not remove thread without safepoint code notice
4124 { MutexLocker ml(Threads_lock);
4125
4126 assert(includes(p), "p must be present");
4127
4128 JavaThread* current = _thread_list;
4129 JavaThread* prev = NULL;
4130
4131 while (current != p) {
4132 prev = current;
4133 current = current->next();
4134 }
4135
4136 if (prev) {
4137 prev->set_next(current->next());
4138 } else {
4139 _thread_list = p->next();
4140 }
4141 _number_of_threads--;
4142 oop threadObj = p->threadObj();
4143 bool daemon = true;
4144 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4145 _number_of_non_daemon_threads--;
4146 daemon = false;
4147
4148 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4149 // on destroy_vm will wake up.
4150 if (number_of_non_daemon_threads() == 1)
4151 Threads_lock->notify_all();
4152 }
4153 ThreadService::remove_thread(p, daemon);
4154
4155 // Make sure that safepoint code disregard this thread. This is needed since
4156 // the thread might mess around with locks after this point. This can cause it
4157 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4158 // of this thread since it is removed from the queue.
4159 p->set_terminated_value();
4160 } // unlock Threads_lock
4161
4162 // Since Events::log uses a lock, we grab it outside the Threads_lock
4163 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4164 }
4165
4166 // Threads_lock must be held when this is called (or must be called during a safepoint)
4167 bool Threads::includes(JavaThread* p) {
4168 assert(Threads_lock->is_locked(), "sanity check");
4169 ALL_JAVA_THREADS(q) {
4170 if (q == p ) {
4171 return true;
4172 }
4173 }
4174 return false;
4175 }
4176
4177 // Operations on the Threads list for GC. These are not explicitly locked,
4178 // but the garbage collector must provide a safe context for them to run.
4179 // In particular, these things should never be called when the Threads_lock
4180 // is held by some other thread. (Note: the Safepoint abstraction also
4181 // uses the Threads_lock to gurantee this property. It also makes sure that
4182 // all threads gets blocked when exiting or starting).
4183
4184 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4185 ALL_JAVA_THREADS(p) {
4186 p->oops_do(f, cld_f, cf);
4187 }
4188 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4189 }
4190
4191 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4192 // Introduce a mechanism allowing parallel threads to claim threads as
4193 // root groups. Overhead should be small enough to use all the time,
4194 // even in sequential code.
4195 SharedHeap* sh = SharedHeap::heap();
4196 // Cannot yet substitute active_workers for n_par_threads
4197 // because of G1CollectedHeap::verify() use of
4198 // SharedHeap::process_roots(). n_par_threads == 0 will
4199 // turn off parallelism in process_roots while active_workers
4200 // is being used for parallelism elsewhere.
4201 bool is_par = sh->n_par_threads() > 0;
4202 assert(!is_par ||
4203 (SharedHeap::heap()->n_par_threads() ==
4204 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4205 int cp = SharedHeap::heap()->strong_roots_parity();
4206 ALL_JAVA_THREADS(p) {
4207 if (p->claim_oops_do(is_par, cp)) {
4208 p->oops_do(f, cld_f, cf);
4209 }
4210 }
4211 VMThread* vmt = VMThread::vm_thread();
4212 if (vmt->claim_oops_do(is_par, cp)) {
4213 vmt->oops_do(f, cld_f, cf);
4214 }
4215 }
4216
4217 #if INCLUDE_ALL_GCS
4218 // Used by ParallelScavenge
4219 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4220 ALL_JAVA_THREADS(p) {
4221 q->enqueue(new ThreadRootsTask(p));
4222 }
4223 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4224 }
4225
4226 // Used by Parallel Old
4227 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4228 ALL_JAVA_THREADS(p) {
4229 q->enqueue(new ThreadRootsMarkingTask(p));
4230 }
4231 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4232 }
4233 #endif // INCLUDE_ALL_GCS
4234
4235 void Threads::nmethods_do(CodeBlobClosure* cf) {
4236 ALL_JAVA_THREADS(p) {
4237 p->nmethods_do(cf);
4238 }
4239 VMThread::vm_thread()->nmethods_do(cf);
4240 }
4241
4242 void Threads::metadata_do(void f(Metadata*)) {
4243 ALL_JAVA_THREADS(p) {
4244 p->metadata_do(f);
4245 }
4246 }
4247
4248 void Threads::gc_epilogue() {
4249 ALL_JAVA_THREADS(p) {
4250 p->gc_epilogue();
4251 }
4252 }
4253
4254 void Threads::gc_prologue() {
4255 ALL_JAVA_THREADS(p) {
4256 p->gc_prologue();
4257 }
4258 }
4259
4260 void Threads::deoptimized_wrt_marked_nmethods() {
4261 ALL_JAVA_THREADS(p) {
4262 p->deoptimized_wrt_marked_nmethods();
4263 }
4264 }
4265
4266
4267 // Get count Java threads that are waiting to enter the specified monitor.
4268 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4269 address monitor, bool doLock) {
4270 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4271 "must grab Threads_lock or be at safepoint");
4272 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4273
4274 int i = 0;
4275 {
4276 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4277 ALL_JAVA_THREADS(p) {
4278 if (p->is_Compiler_thread()) continue;
4279
4280 address pending = (address)p->current_pending_monitor();
4281 if (pending == monitor) { // found a match
4282 if (i < count) result->append(p); // save the first count matches
4283 i++;
4284 }
4285 }
4286 }
4287 return result;
4288 }
4289
4290
4291 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4292 assert(doLock ||
4293 Threads_lock->owned_by_self() ||
4294 SafepointSynchronize::is_at_safepoint(),
4295 "must grab Threads_lock or be at safepoint");
4296
4297 // NULL owner means not locked so we can skip the search
4298 if (owner == NULL) return NULL;
4299
4300 {
4301 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4302 ALL_JAVA_THREADS(p) {
4303 // first, see if owner is the address of a Java thread
4304 if (owner == (address)p) return p;
4305 }
4306 }
4307 // Cannot assert on lack of success here since this function may be
4308 // used by code that is trying to report useful problem information
4309 // like deadlock detection.
4310 if (UseHeavyMonitors) return NULL;
4311
4312 //
4313 // If we didn't find a matching Java thread and we didn't force use of
4314 // heavyweight monitors, then the owner is the stack address of the
4315 // Lock Word in the owning Java thread's stack.
4316 //
4317 JavaThread* the_owner = NULL;
4318 {
4319 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4320 ALL_JAVA_THREADS(q) {
4321 if (q->is_lock_owned(owner)) {
4322 the_owner = q;
4323 break;
4324 }
4325 }
4326 }
4327 // cannot assert on lack of success here; see above comment
4328 return the_owner;
4329 }
4330
4331 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4332 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4333 char buf[32];
4334 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4335
4336 st->print_cr("Full thread dump %s (%s %s):",
4337 Abstract_VM_Version::vm_name(),
4338 Abstract_VM_Version::vm_release(),
4339 Abstract_VM_Version::vm_info_string()
4340 );
4341 st->cr();
4342
4343 #if INCLUDE_ALL_GCS
4344 // Dump concurrent locks
4345 ConcurrentLocksDump concurrent_locks;
4346 if (print_concurrent_locks) {
4347 concurrent_locks.dump_at_safepoint();
4348 }
4349 #endif // INCLUDE_ALL_GCS
4350
4351 ALL_JAVA_THREADS(p) {
4352 ResourceMark rm;
4353 p->print_on(st);
4354 if (print_stacks) {
4355 if (internal_format) {
4356 p->trace_stack();
4357 } else {
4358 p->print_stack_on(st);
4359 }
4360 }
4361 st->cr();
4362 #if INCLUDE_ALL_GCS
4363 if (print_concurrent_locks) {
4364 concurrent_locks.print_locks_on(p, st);
4365 }
4366 #endif // INCLUDE_ALL_GCS
4367 }
4368
4369 VMThread::vm_thread()->print_on(st);
4370 st->cr();
4371 Universe::heap()->print_gc_threads_on(st);
4372 WatcherThread* wt = WatcherThread::watcher_thread();
4373 if (wt != NULL) {
4374 wt->print_on(st);
4375 st->cr();
4376 }
4377 CompileBroker::print_compiler_threads_on(st);
4378 st->flush();
4379 }
4380
4381 // Threads::print_on_error() is called by fatal error handler. It's possible
4382 // that VM is not at safepoint and/or current thread is inside signal handler.
4383 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4384 // memory (even in resource area), it might deadlock the error handler.
4385 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4386 bool found_current = false;
4387 st->print_cr("Java Threads: ( => current thread )");
4388 ALL_JAVA_THREADS(thread) {
4389 bool is_current = (current == thread);
4390 found_current = found_current || is_current;
4391
4392 st->print("%s", is_current ? "=>" : " ");
4393
4394 st->print(PTR_FORMAT, thread);
4395 st->print(" ");
4396 thread->print_on_error(st, buf, buflen);
4397 st->cr();
4398 }
4399 st->cr();
4400
4401 st->print_cr("Other Threads:");
4402 if (VMThread::vm_thread()) {
4403 bool is_current = (current == VMThread::vm_thread());
4404 found_current = found_current || is_current;
4405 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4406
4407 st->print(PTR_FORMAT, VMThread::vm_thread());
4408 st->print(" ");
4409 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4410 st->cr();
4411 }
4412 WatcherThread* wt = WatcherThread::watcher_thread();
4413 if (wt != NULL) {
4414 bool is_current = (current == wt);
4415 found_current = found_current || is_current;
4416 st->print("%s", is_current ? "=>" : " ");
4417
4418 st->print(PTR_FORMAT, wt);
4419 st->print(" ");
4420 wt->print_on_error(st, buf, buflen);
4421 st->cr();
4422 }
4423 if (!found_current) {
4424 st->cr();
4425 st->print("=>" PTR_FORMAT " (exited) ", current);
4426 current->print_on_error(st, buf, buflen);
4427 st->cr();
4428 }
4429 }
4430
4431 // Internal SpinLock and Mutex
4432 // Based on ParkEvent
4433
4434 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4435 //
4436 // We employ SpinLocks _only for low-contention, fixed-length
4437 // short-duration critical sections where we're concerned
4438 // about native mutex_t or HotSpot Mutex:: latency.
4439 // The mux construct provides a spin-then-block mutual exclusion
4440 // mechanism.
4441 //
4442 // Testing has shown that contention on the ListLock guarding gFreeList
4443 // is common. If we implement ListLock as a simple SpinLock it's common
4444 // for the JVM to devolve to yielding with little progress. This is true
4445 // despite the fact that the critical sections protected by ListLock are
4446 // extremely short.
4447 //
4448 // TODO-FIXME: ListLock should be of type SpinLock.
4449 // We should make this a 1st-class type, integrated into the lock
4450 // hierarchy as leaf-locks. Critically, the SpinLock structure
4451 // should have sufficient padding to avoid false-sharing and excessive
4452 // cache-coherency traffic.
4453
4454
4455 typedef volatile int SpinLockT ;
4456
4457 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4458 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4459 return ; // normal fast-path return
4460 }
4461
4462 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4463 TEVENT (SpinAcquire - ctx) ;
4464 int ctr = 0 ;
4465 int Yields = 0 ;
4466 for (;;) {
4467 while (*adr != 0) {
4468 ++ctr ;
4469 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4470 if (Yields > 5) {
4471 os::naked_short_sleep(1);
4472 } else {
4473 os::NakedYield() ;
4474 ++Yields ;
4475 }
4476 } else {
4477 SpinPause() ;
4478 }
4479 }
4480 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4481 }
4482 }
4483
4484 void Thread::SpinRelease (volatile int * adr) {
4485 assert (*adr != 0, "invariant") ;
4486 OrderAccess::fence() ; // guarantee at least release consistency.
4487 // Roach-motel semantics.
4488 // It's safe if subsequent LDs and STs float "up" into the critical section,
4489 // but prior LDs and STs within the critical section can't be allowed
4490 // to reorder or float past the ST that releases the lock.
4491 *adr = 0 ;
4492 }
4493
4494 // muxAcquire and muxRelease:
4495 //
4496 // * muxAcquire and muxRelease support a single-word lock-word construct.
4497 // The LSB of the word is set IFF the lock is held.
4498 // The remainder of the word points to the head of a singly-linked list
4499 // of threads blocked on the lock.
4500 //
4501 // * The current implementation of muxAcquire-muxRelease uses its own
4502 // dedicated Thread._MuxEvent instance. If we're interested in
4503 // minimizing the peak number of extant ParkEvent instances then
4504 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4505 // as certain invariants were satisfied. Specifically, care would need
4506 // to be taken with regards to consuming unpark() "permits".
4507 // A safe rule of thumb is that a thread would never call muxAcquire()
4508 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4509 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4510 // consume an unpark() permit intended for monitorenter, for instance.
4511 // One way around this would be to widen the restricted-range semaphore
4512 // implemented in park(). Another alternative would be to provide
4513 // multiple instances of the PlatformEvent() for each thread. One
4514 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4515 //
4516 // * Usage:
4517 // -- Only as leaf locks
4518 // -- for short-term locking only as muxAcquire does not perform
4519 // thread state transitions.
4520 //
4521 // Alternatives:
4522 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4523 // but with parking or spin-then-park instead of pure spinning.
4524 // * Use Taura-Oyama-Yonenzawa locks.
4525 // * It's possible to construct a 1-0 lock if we encode the lockword as
4526 // (List,LockByte). Acquire will CAS the full lockword while Release
4527 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4528 // acquiring threads use timers (ParkTimed) to detect and recover from
4529 // the stranding window. Thread/Node structures must be aligned on 256-byte
4530 // boundaries by using placement-new.
4531 // * Augment MCS with advisory back-link fields maintained with CAS().
4532 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4533 // The validity of the backlinks must be ratified before we trust the value.
4534 // If the backlinks are invalid the exiting thread must back-track through the
4535 // the forward links, which are always trustworthy.
4536 // * Add a successor indication. The LockWord is currently encoded as
4537 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4538 // to provide the usual futile-wakeup optimization.
4539 // See RTStt for details.
4540 // * Consider schedctl.sc_nopreempt to cover the critical section.
4541 //
4542
4543
4544 typedef volatile intptr_t MutexT ; // Mux Lock-word
4545 enum MuxBits { LOCKBIT = 1 } ;
4546
4547 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4548 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4549 if (w == 0) return ;
4550 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4551 return ;
4552 }
4553
4554 TEVENT (muxAcquire - Contention) ;
4555 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4556 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4557 for (;;) {
4558 int its = (os::is_MP() ? 100 : 0) + 1 ;
4559
4560 // Optional spin phase: spin-then-park strategy
4561 while (--its >= 0) {
4562 w = *Lock ;
4563 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4564 return ;
4565 }
4566 }
4567
4568 Self->reset() ;
4569 Self->OnList = intptr_t(Lock) ;
4570 // The following fence() isn't _strictly necessary as the subsequent
4571 // CAS() both serializes execution and ratifies the fetched *Lock value.
4572 OrderAccess::fence();
4573 for (;;) {
4574 w = *Lock ;
4575 if ((w & LOCKBIT) == 0) {
4576 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4577 Self->OnList = 0 ; // hygiene - allows stronger asserts
4578 return ;
4579 }
4580 continue ; // Interference -- *Lock changed -- Just retry
4581 }
4582 assert (w & LOCKBIT, "invariant") ;
4583 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4584 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4585 }
4586
4587 while (Self->OnList != 0) {
4588 Self->park() ;
4589 }
4590 }
4591 }
4592
4593 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4594 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4595 if (w == 0) return ;
4596 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4597 return ;
4598 }
4599
4600 TEVENT (muxAcquire - Contention) ;
4601 ParkEvent * ReleaseAfter = NULL ;
4602 if (ev == NULL) {
4603 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4604 }
4605 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4606 for (;;) {
4607 guarantee (ev->OnList == 0, "invariant") ;
4608 int its = (os::is_MP() ? 100 : 0) + 1 ;
4609
4610 // Optional spin phase: spin-then-park strategy
4611 while (--its >= 0) {
4612 w = *Lock ;
4613 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4614 if (ReleaseAfter != NULL) {
4615 ParkEvent::Release (ReleaseAfter) ;
4616 }
4617 return ;
4618 }
4619 }
4620
4621 ev->reset() ;
4622 ev->OnList = intptr_t(Lock) ;
4623 // The following fence() isn't _strictly necessary as the subsequent
4624 // CAS() both serializes execution and ratifies the fetched *Lock value.
4625 OrderAccess::fence();
4626 for (;;) {
4627 w = *Lock ;
4628 if ((w & LOCKBIT) == 0) {
4629 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4630 ev->OnList = 0 ;
4631 // We call ::Release while holding the outer lock, thus
4632 // artificially lengthening the critical section.
4633 // Consider deferring the ::Release() until the subsequent unlock(),
4634 // after we've dropped the outer lock.
4635 if (ReleaseAfter != NULL) {
4636 ParkEvent::Release (ReleaseAfter) ;
4637 }
4638 return ;
4639 }
4640 continue ; // Interference -- *Lock changed -- Just retry
4641 }
4642 assert (w & LOCKBIT, "invariant") ;
4643 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4644 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4645 }
4646
4647 while (ev->OnList != 0) {
4648 ev->park() ;
4649 }
4650 }
4651 }
4652
4653 // Release() must extract a successor from the list and then wake that thread.
4654 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4655 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4656 // Release() would :
4657 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4658 // (B) Extract a successor from the private list "in-hand"
4659 // (C) attempt to CAS() the residual back into *Lock over null.
4660 // If there were any newly arrived threads and the CAS() would fail.
4661 // In that case Release() would detach the RATs, re-merge the list in-hand
4662 // with the RATs and repeat as needed. Alternately, Release() might
4663 // detach and extract a successor, but then pass the residual list to the wakee.
4664 // The wakee would be responsible for reattaching and remerging before it
4665 // competed for the lock.
4666 //
4667 // Both "pop" and DMR are immune from ABA corruption -- there can be
4668 // multiple concurrent pushers, but only one popper or detacher.
4669 // This implementation pops from the head of the list. This is unfair,
4670 // but tends to provide excellent throughput as hot threads remain hot.
4671 // (We wake recently run threads first).
4672
4673 void Thread::muxRelease (volatile intptr_t * Lock) {
4674 for (;;) {
4675 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4676 assert (w & LOCKBIT, "invariant") ;
4677 if (w == LOCKBIT) return ;
4678 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4679 assert (List != NULL, "invariant") ;
4680 assert (List->OnList == intptr_t(Lock), "invariant") ;
4681 ParkEvent * nxt = List->ListNext ;
4682
4683 // The following CAS() releases the lock and pops the head element.
4684 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4685 continue ;
4686 }
4687 List->OnList = 0 ;
4688 OrderAccess::fence() ;
4689 List->unpark () ;
4690 return ;
4691 }
4692 }
4693
4694
4695 void Threads::verify() {
4696 ALL_JAVA_THREADS(p) {
4697 p->verify();
4698 }
4699 VMThread* thread = VMThread::vm_thread();
4700 if (thread != NULL) thread->verify();
4701 }