1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jfr/jfrEvents.hpp"
36 #include "jvmtifiles/jvmtiEnv.hpp"
37 #include "memory/gcLocker.inline.hpp"
38 #include "memory/metaspaceShared.hpp"
39 #include "memory/oopFactory.hpp"
40 #include "memory/universe.inline.hpp"
41 #include "oops/instanceKlass.hpp"
42 #include "oops/objArrayOop.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "oops/symbol.hpp"
45 #include "prims/jvm_misc.hpp"
46 #include "prims/jvmtiExport.hpp"
47 #include "prims/jvmtiThreadState.hpp"
48 #include "prims/privilegedStack.hpp"
49 #include "runtime/arguments.hpp"
50 #include "runtime/biasedLocking.hpp"
51 #include "runtime/deoptimization.hpp"
52 #include "runtime/fprofiler.hpp"
53 #include "runtime/frame.inline.hpp"
54 #include "runtime/init.hpp"
55 #include "runtime/interfaceSupport.hpp"
56 #include "runtime/java.hpp"
57 #include "runtime/javaCalls.hpp"
58 #include "runtime/jniPeriodicChecker.hpp"
59 #include "runtime/memprofiler.hpp"
60 #include "runtime/mutexLocker.hpp"
61 #include "runtime/objectMonitor.hpp"
62 #include "runtime/orderAccess.inline.hpp"
63 #include "runtime/osThread.hpp"
64 #include "runtime/safepoint.hpp"
65 #include "runtime/sharedRuntime.hpp"
66 #include "runtime/statSampler.hpp"
67 #include "runtime/stubRoutines.hpp"
68 #include "runtime/task.hpp"
69 #include "runtime/thread.inline.hpp"
70 #include "runtime/threadCritical.hpp"
71 #include "runtime/threadLocalStorage.hpp"
72 #include "runtime/vframe.hpp"
73 #include "runtime/vframeArray.hpp"
74 #include "runtime/vframe_hp.hpp"
75 #include "runtime/vmThread.hpp"
76 #include "runtime/vm_operations.hpp"
77 #include "services/attachListener.hpp"
78 #include "services/management.hpp"
79 #include "services/memTracker.hpp"
80 #include "services/threadService.hpp"
81 #include "utilities/defaultStream.hpp"
82 #include "utilities/dtrace.hpp"
83 #include "utilities/events.hpp"
84 #include "utilities/preserveException.hpp"
85 #include "utilities/macros.hpp"
86 #ifdef TARGET_OS_FAMILY_linux
87 # include "os_linux.inline.hpp"
88 #endif
89 #ifdef TARGET_OS_FAMILY_solaris
90 # include "os_solaris.inline.hpp"
91 #endif
92 #ifdef TARGET_OS_FAMILY_windows
93 # include "os_windows.inline.hpp"
94 #endif
95 #ifdef TARGET_OS_FAMILY_bsd
96 # include "os_bsd.inline.hpp"
97 #endif
98 #if INCLUDE_ALL_GCS
99 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
100 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
101 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
102 #endif // INCLUDE_ALL_GCS
103 #ifdef COMPILER1
104 #include "c1/c1_Compiler.hpp"
105 #endif
106 #ifdef COMPILER2
107 #include "opto/c2compiler.hpp"
108 #include "opto/idealGraphPrinter.hpp"
109 #endif
110 #if INCLUDE_RTM_OPT
111 #include "runtime/rtmLocking.hpp"
112 #endif
113 #if INCLUDE_JFR
114 #include "jfr/jfr.hpp"
115 #endif
116
117 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
118
119 #ifdef DTRACE_ENABLED
120
121 // Only bother with this argument setup if dtrace is available
122
123 #ifndef USDT2
124 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
125 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
126 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
127 intptr_t, intptr_t, bool);
128 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
129 intptr_t, intptr_t, bool);
130
131 #define DTRACE_THREAD_PROBE(probe, javathread) \
132 { \
133 ResourceMark rm(this); \
134 int len = 0; \
135 const char* name = (javathread)->get_thread_name(); \
136 len = strlen(name); \
137 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
138 name, len, \
139 java_lang_Thread::thread_id((javathread)->threadObj()), \
140 (javathread)->osthread()->thread_id(), \
141 java_lang_Thread::is_daemon((javathread)->threadObj())); \
142 }
143
144 #else /* USDT2 */
145
146 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
147 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
148
149 #define DTRACE_THREAD_PROBE(probe, javathread) \
150 { \
151 ResourceMark rm(this); \
152 int len = 0; \
153 const char* name = (javathread)->get_thread_name(); \
154 len = strlen(name); \
155 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
156 (char *) name, len, \
157 java_lang_Thread::thread_id((javathread)->threadObj()), \
158 (uintptr_t) (javathread)->osthread()->thread_id(), \
159 java_lang_Thread::is_daemon((javathread)->threadObj())); \
160 }
161
162 #endif /* USDT2 */
163
164 #else // ndef DTRACE_ENABLED
165
166 #define DTRACE_THREAD_PROBE(probe, javathread)
167
168 #endif // ndef DTRACE_ENABLED
169
170
171 // Class hierarchy
172 // - Thread
173 // - VMThread
174 // - WatcherThread
175 // - ConcurrentMarkSweepThread
176 // - JavaThread
177 // - CompilerThread
178
179 // ======= Thread ========
180 // Support for forcing alignment of thread objects for biased locking
181 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
182 if (UseBiasedLocking) {
183 const int alignment = markOopDesc::biased_lock_alignment;
184 size_t aligned_size = size + (alignment - sizeof(intptr_t));
185 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
186 : AllocateHeap(aligned_size, flags, CURRENT_PC,
187 AllocFailStrategy::RETURN_NULL);
188 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
189 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
190 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
191 "JavaThread alignment code overflowed allocated storage");
192 if (TraceBiasedLocking) {
193 if (aligned_addr != real_malloc_addr)
194 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
195 real_malloc_addr, aligned_addr);
196 }
197 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
198 return aligned_addr;
199 } else {
200 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
201 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
202 }
203 }
204
205 void Thread::operator delete(void* p) {
206 if (UseBiasedLocking) {
207 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
208 FreeHeap(real_malloc_addr, mtThread);
209 } else {
210 FreeHeap(p, mtThread);
211 }
212 }
213
214
215 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
216 // JavaThread
217
218
219 Thread::Thread() {
220 // stack and get_thread
221 set_stack_base(NULL);
222 set_stack_size(0);
223 set_self_raw_id(0);
224 set_lgrp_id(-1);
225
226 // allocated data structures
227 set_osthread(NULL);
228 set_resource_area(new (mtThread)ResourceArea());
229 DEBUG_ONLY(_current_resource_mark = NULL;)
230 set_handle_area(new (mtThread) HandleArea(NULL));
231 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
232 set_active_handles(NULL);
233 set_free_handle_block(NULL);
234 set_last_handle_mark(NULL);
235
236 // This initial value ==> never claimed.
237 _oops_do_parity = 0;
238
239 _metadata_on_stack_buffer = NULL;
240
241 // the handle mark links itself to last_handle_mark
242 new HandleMark(this);
243
244 // plain initialization
245 debug_only(_owned_locks = NULL;)
246 debug_only(_allow_allocation_count = 0;)
247 NOT_PRODUCT(_allow_safepoint_count = 0;)
248 NOT_PRODUCT(_skip_gcalot = false;)
249 _jvmti_env_iteration_count = 0;
250 set_allocated_bytes(0);
251 _vm_operation_started_count = 0;
252 _vm_operation_completed_count = 0;
253 _current_pending_monitor = NULL;
254 _current_pending_monitor_is_from_java = true;
255 _current_waiting_monitor = NULL;
256 _num_nested_signal = 0;
257 omFreeList = NULL ;
258 omFreeCount = 0 ;
259 omFreeProvision = 32 ;
260 omInUseList = NULL ;
261 omInUseCount = 0 ;
262
263 #ifdef ASSERT
264 _visited_for_critical_count = false;
265 #endif
266
267 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
268 _suspend_flags = 0;
269
270 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
271 _hashStateX = os::random() ;
272 _hashStateY = 842502087 ;
273 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
274 _hashStateW = 273326509 ;
275
276 _OnTrap = 0 ;
277 _schedctl = NULL ;
278 _Stalled = 0 ;
279 _TypeTag = 0x2BAD ;
280
281 // Many of the following fields are effectively final - immutable
282 // Note that nascent threads can't use the Native Monitor-Mutex
283 // construct until the _MutexEvent is initialized ...
284 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
285 // we might instead use a stack of ParkEvents that we could provision on-demand.
286 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
287 // and ::Release()
288 _ParkEvent = ParkEvent::Allocate (this) ;
289 _SleepEvent = ParkEvent::Allocate (this) ;
290 _MutexEvent = ParkEvent::Allocate (this) ;
291 _MuxEvent = ParkEvent::Allocate (this) ;
292
293 #ifdef CHECK_UNHANDLED_OOPS
294 if (CheckUnhandledOops) {
295 _unhandled_oops = new UnhandledOops(this);
296 }
297 #endif // CHECK_UNHANDLED_OOPS
298 #ifdef ASSERT
299 if (UseBiasedLocking) {
300 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
301 assert(this == _real_malloc_address ||
302 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
303 "bug in forced alignment of thread objects");
304 }
305 #endif /* ASSERT */
306 }
307
308 void Thread::initialize_thread_local_storage() {
309 // Note: Make sure this method only calls
310 // non-blocking operations. Otherwise, it might not work
311 // with the thread-startup/safepoint interaction.
312
313 // During Java thread startup, safepoint code should allow this
314 // method to complete because it may need to allocate memory to
315 // store information for the new thread.
316
317 // initialize structure dependent on thread local storage
318 ThreadLocalStorage::set_thread(this);
319 }
320
321 void Thread::record_stack_base_and_size() {
322 set_stack_base(os::current_stack_base());
323 set_stack_size(os::current_stack_size());
324 if (is_Java_thread()) {
325 ((JavaThread*) this)->set_stack_overflow_limit();
326 }
327 // CR 7190089: on Solaris, primordial thread's stack is adjusted
328 // in initialize_thread(). Without the adjustment, stack size is
329 // incorrect if stack is set to unlimited (ulimit -s unlimited).
330 // So far, only Solaris has real implementation of initialize_thread().
331 //
332 // set up any platform-specific state.
333 os::initialize_thread(this);
334
335 #if INCLUDE_NMT
336 // record thread's native stack, stack grows downward
337 address stack_low_addr = stack_base() - stack_size();
338 MemTracker::record_thread_stack(stack_low_addr, stack_size());
339 #endif // INCLUDE_NMT
340 }
341
342
343 Thread::~Thread() {
344 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
345 ObjectSynchronizer::omFlush (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 if (active_handles() != NULL) {
840 active_handles()->oops_do(f);
841 }
842 // Do oop for ThreadShadow
843 f->do_oop((oop*)&_pending_exception);
844 handle_area()->oops_do(f);
845 }
846
847 void Thread::nmethods_do(CodeBlobClosure* cf) {
848 // no nmethods in a generic thread...
849 }
850
851 void Thread::metadata_do(void f(Metadata*)) {
852 if (metadata_handles() != NULL) {
853 for (int i = 0; i< metadata_handles()->length(); i++) {
854 f(metadata_handles()->at(i));
855 }
856 }
857 }
858
859 void Thread::print_on(outputStream* st) const {
860 // get_priority assumes osthread initialized
861 if (osthread() != NULL) {
862 int os_prio;
863 if (os::get_native_priority(this, &os_prio) == OS_OK) {
864 st->print("os_prio=%d ", os_prio);
865 }
866 st->print("tid=" INTPTR_FORMAT " ", this);
867 ext().print_on(st);
868 osthread()->print_on(st);
869 }
870 debug_only(if (WizardMode) print_owned_locks_on(st);)
871 }
872
873 // Thread::print_on_error() is called by fatal error handler. Don't use
874 // any lock or allocate memory.
875 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
876 if (is_VM_thread()) st->print("VMThread");
877 else if (is_Compiler_thread()) st->print("CompilerThread");
878 else if (is_Java_thread()) st->print("JavaThread");
879 else if (is_GC_task_thread()) st->print("GCTaskThread");
880 else if (is_Watcher_thread()) st->print("WatcherThread");
881 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
882 else st->print("Thread");
883
884 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
885 _stack_base - _stack_size, _stack_base);
886
887 if (osthread()) {
888 st->print(" [id=%d]", osthread()->thread_id());
889 }
890 }
891
892 #ifdef ASSERT
893 void Thread::print_owned_locks_on(outputStream* st) const {
894 Monitor *cur = _owned_locks;
895 if (cur == NULL) {
896 st->print(" (no locks) ");
897 } else {
898 st->print_cr(" Locks owned:");
899 while(cur) {
900 cur->print_on(st);
901 cur = cur->next();
902 }
903 }
904 }
905
906 static int ref_use_count = 0;
907
908 bool Thread::owns_locks_but_compiled_lock() const {
909 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
910 if (cur != Compile_lock) return true;
911 }
912 return false;
913 }
914
915
916 #endif
917
918 #ifndef PRODUCT
919
920 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
921 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
922 // no threads which allow_vm_block's are held
923 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
924 // Check if current thread is allowed to block at a safepoint
925 if (!(_allow_safepoint_count == 0))
926 fatal("Possible safepoint reached by thread that does not allow it");
927 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
928 fatal("LEAF method calling lock?");
929 }
930
931 #ifdef ASSERT
932 if (potential_vm_operation && is_Java_thread()
933 && !Universe::is_bootstrapping()) {
934 // Make sure we do not hold any locks that the VM thread also uses.
935 // This could potentially lead to deadlocks
936 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
937 // Threads_lock is special, since the safepoint synchronization will not start before this is
938 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
939 // since it is used to transfer control between JavaThreads and the VMThread
940 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
941 if ( (cur->allow_vm_block() &&
942 cur != Threads_lock &&
943 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
944 cur != VMOperationRequest_lock &&
945 cur != VMOperationQueue_lock) ||
946 cur->rank() == Mutex::special) {
947 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
948 }
949 }
950 }
951
952 if (GCALotAtAllSafepoints) {
953 // We could enter a safepoint here and thus have a gc
954 InterfaceSupport::check_gc_alot();
955 }
956 #endif
957 }
958 #endif
959
960 bool Thread::is_in_stack(address adr) const {
961 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
962 address end = os::current_stack_pointer();
963 // Allow non Java threads to call this without stack_base
964 if (_stack_base == NULL) return true;
965 if (stack_base() > adr && adr >= end) return true;
966
967 return false;
968 }
969
970
971 bool Thread::is_in_usable_stack(address adr) const {
972 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
973 size_t usable_stack_size = _stack_size - stack_guard_size;
974
975 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
976 }
977
978
979 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
980 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
981 // used for compilation in the future. If that change is made, the need for these methods
982 // should be revisited, and they should be removed if possible.
983
984 bool Thread::is_lock_owned(address adr) const {
985 return on_local_stack(adr);
986 }
987
988 bool Thread::set_as_starting_thread() {
989 // NOTE: this must be called inside the main thread.
990 return os::create_main_thread((JavaThread*)this);
991 }
992
993 static void initialize_class(Symbol* class_name, TRAPS) {
994 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
995 InstanceKlass::cast(klass)->initialize(CHECK);
996 }
997
998
999 // Creates the initial ThreadGroup
1000 static Handle create_initial_thread_group(TRAPS) {
1001 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1002 instanceKlassHandle klass (THREAD, k);
1003
1004 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1005 {
1006 JavaValue result(T_VOID);
1007 JavaCalls::call_special(&result,
1008 system_instance,
1009 klass,
1010 vmSymbols::object_initializer_name(),
1011 vmSymbols::void_method_signature(),
1012 CHECK_NH);
1013 }
1014 Universe::set_system_thread_group(system_instance());
1015
1016 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1017 {
1018 JavaValue result(T_VOID);
1019 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1020 JavaCalls::call_special(&result,
1021 main_instance,
1022 klass,
1023 vmSymbols::object_initializer_name(),
1024 vmSymbols::threadgroup_string_void_signature(),
1025 system_instance,
1026 string,
1027 CHECK_NH);
1028 }
1029 return main_instance;
1030 }
1031
1032 // Creates the initial Thread
1033 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1034 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1035 instanceKlassHandle klass (THREAD, k);
1036 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1037
1038 java_lang_Thread::set_thread(thread_oop(), thread);
1039 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1040 thread->set_threadObj(thread_oop());
1041
1042 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1043
1044 JavaValue result(T_VOID);
1045 JavaCalls::call_special(&result, thread_oop,
1046 klass,
1047 vmSymbols::object_initializer_name(),
1048 vmSymbols::threadgroup_string_void_signature(),
1049 thread_group,
1050 string,
1051 CHECK_NULL);
1052 return thread_oop();
1053 }
1054
1055 static void call_initializeSystemClass(TRAPS) {
1056 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1057 instanceKlassHandle klass (THREAD, k);
1058
1059 JavaValue result(T_VOID);
1060 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1061 vmSymbols::void_method_signature(), CHECK);
1062 }
1063
1064 char java_runtime_name[128] = "";
1065 char java_runtime_version[128] = "";
1066
1067 // extract the JRE name from sun.misc.Version.java_runtime_name
1068 static const char* get_java_runtime_name(TRAPS) {
1069 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1070 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1071 fieldDescriptor fd;
1072 bool found = k != NULL &&
1073 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1074 vmSymbols::string_signature(), &fd);
1075 if (found) {
1076 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1077 if (name_oop == NULL)
1078 return NULL;
1079 const char* name = java_lang_String::as_utf8_string(name_oop,
1080 java_runtime_name,
1081 sizeof(java_runtime_name));
1082 return name;
1083 } else {
1084 return NULL;
1085 }
1086 }
1087
1088 // extract the JRE version from sun.misc.Version.java_runtime_version
1089 static const char* get_java_runtime_version(TRAPS) {
1090 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1091 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1092 fieldDescriptor fd;
1093 bool found = k != NULL &&
1094 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1095 vmSymbols::string_signature(), &fd);
1096 if (found) {
1097 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1098 if (name_oop == NULL)
1099 return NULL;
1100 const char* name = java_lang_String::as_utf8_string(name_oop,
1101 java_runtime_version,
1102 sizeof(java_runtime_version));
1103 return name;
1104 } else {
1105 return NULL;
1106 }
1107 }
1108
1109 // General purpose hook into Java code, run once when the VM is initialized.
1110 // The Java library method itself may be changed independently from the VM.
1111 static void call_postVMInitHook(TRAPS) {
1112 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1113 instanceKlassHandle klass (THREAD, k);
1114 if (klass.not_null()) {
1115 JavaValue result(T_VOID);
1116 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1117 vmSymbols::void_method_signature(),
1118 CHECK);
1119 }
1120 }
1121
1122 static void reset_vm_info_property(TRAPS) {
1123 // the vm info string
1124 ResourceMark rm(THREAD);
1125 const char *vm_info = VM_Version::vm_info_string();
1126
1127 // java.lang.System class
1128 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1129 instanceKlassHandle klass (THREAD, k);
1130
1131 // setProperty arguments
1132 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1133 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1134
1135 // return value
1136 JavaValue r(T_OBJECT);
1137
1138 // public static String setProperty(String key, String value);
1139 JavaCalls::call_static(&r,
1140 klass,
1141 vmSymbols::setProperty_name(),
1142 vmSymbols::string_string_string_signature(),
1143 key_str,
1144 value_str,
1145 CHECK);
1146 }
1147
1148
1149 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1150 assert(thread_group.not_null(), "thread group should be specified");
1151 assert(threadObj() == NULL, "should only create Java thread object once");
1152
1153 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1154 instanceKlassHandle klass (THREAD, k);
1155 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1156
1157 java_lang_Thread::set_thread(thread_oop(), this);
1158 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1159 set_threadObj(thread_oop());
1160
1161 JavaValue result(T_VOID);
1162 if (thread_name != NULL) {
1163 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1164 // Thread gets assigned specified name and null target
1165 JavaCalls::call_special(&result,
1166 thread_oop,
1167 klass,
1168 vmSymbols::object_initializer_name(),
1169 vmSymbols::threadgroup_string_void_signature(),
1170 thread_group, // Argument 1
1171 name, // Argument 2
1172 THREAD);
1173 } else {
1174 // Thread gets assigned name "Thread-nnn" and null target
1175 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1176 JavaCalls::call_special(&result,
1177 thread_oop,
1178 klass,
1179 vmSymbols::object_initializer_name(),
1180 vmSymbols::threadgroup_runnable_void_signature(),
1181 thread_group, // Argument 1
1182 Handle(), // Argument 2
1183 THREAD);
1184 }
1185
1186
1187 if (daemon) {
1188 java_lang_Thread::set_daemon(thread_oop());
1189 }
1190
1191 if (HAS_PENDING_EXCEPTION) {
1192 return;
1193 }
1194
1195 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1196 Handle threadObj(this, this->threadObj());
1197
1198 JavaCalls::call_special(&result,
1199 thread_group,
1200 group,
1201 vmSymbols::add_method_name(),
1202 vmSymbols::thread_void_signature(),
1203 threadObj, // Arg 1
1204 THREAD);
1205
1206
1207 }
1208
1209 // NamedThread -- non-JavaThread subclasses with multiple
1210 // uniquely named instances should derive from this.
1211 NamedThread::NamedThread() : Thread() {
1212 _name = NULL;
1213 _processed_thread = NULL;
1214 }
1215
1216 NamedThread::~NamedThread() {
1217 JFR_ONLY(Jfr::on_thread_exit(this);)
1218 if (_name != NULL) {
1219 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1220 _name = NULL;
1221 }
1222 }
1223
1224 void NamedThread::set_name(const char* format, ...) {
1225 guarantee(_name == NULL, "Only get to set name once.");
1226 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1227 guarantee(_name != NULL, "alloc failure");
1228 va_list ap;
1229 va_start(ap, format);
1230 jio_vsnprintf(_name, max_name_len, format, ap);
1231 va_end(ap);
1232 }
1233
1234 // ======= WatcherThread ========
1235
1236 // The watcher thread exists to simulate timer interrupts. It should
1237 // be replaced by an abstraction over whatever native support for
1238 // timer interrupts exists on the platform.
1239
1240 WatcherThread* WatcherThread::_watcher_thread = NULL;
1241 bool WatcherThread::_startable = false;
1242 volatile bool WatcherThread::_should_terminate = false;
1243
1244 WatcherThread::WatcherThread() : Thread() {
1245 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1246 if (os::create_thread(this, os::watcher_thread)) {
1247 _watcher_thread = this;
1248
1249 // Set the watcher thread to the highest OS priority which should not be
1250 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1251 // is created. The only normal thread using this priority is the reference
1252 // handler thread, which runs for very short intervals only.
1253 // If the VMThread's priority is not lower than the WatcherThread profiling
1254 // will be inaccurate.
1255 os::set_priority(this, MaxPriority);
1256 if (!DisableStartThread) {
1257 os::start_thread(this);
1258 }
1259 }
1260 }
1261
1262 int WatcherThread::sleep() const {
1263 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1264
1265 // remaining will be zero if there are no tasks,
1266 // causing the WatcherThread to sleep until a task is
1267 // enrolled
1268 int remaining = PeriodicTask::time_to_wait();
1269 int time_slept = 0;
1270
1271 // we expect this to timeout - we only ever get unparked when
1272 // we should terminate or when a new task has been enrolled
1273 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1274
1275 jlong time_before_loop = os::javaTimeNanos();
1276
1277 for (;;) {
1278 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1279 jlong now = os::javaTimeNanos();
1280
1281 if (remaining == 0) {
1282 // if we didn't have any tasks we could have waited for a long time
1283 // consider the time_slept zero and reset time_before_loop
1284 time_slept = 0;
1285 time_before_loop = now;
1286 } else {
1287 // need to recalulate since we might have new tasks in _tasks
1288 time_slept = (int) ((now - time_before_loop) / 1000000);
1289 }
1290
1291 // Change to task list or spurious wakeup of some kind
1292 if (timedout || _should_terminate) {
1293 break;
1294 }
1295
1296 remaining = PeriodicTask::time_to_wait();
1297 if (remaining == 0) {
1298 // Last task was just disenrolled so loop around and wait until
1299 // another task gets enrolled
1300 continue;
1301 }
1302
1303 remaining -= time_slept;
1304 if (remaining <= 0)
1305 break;
1306 }
1307
1308 return time_slept;
1309 }
1310
1311 void WatcherThread::run() {
1312 assert(this == watcher_thread(), "just checking");
1313
1314 this->record_stack_base_and_size();
1315 this->initialize_thread_local_storage();
1316 this->set_native_thread_name(this->name());
1317 this->set_active_handles(JNIHandleBlock::allocate_block());
1318 while(!_should_terminate) {
1319 assert(watcher_thread() == Thread::current(), "thread consistency check");
1320 assert(watcher_thread() == this, "thread consistency check");
1321
1322 // Calculate how long it'll be until the next PeriodicTask work
1323 // should be done, and sleep that amount of time.
1324 int time_waited = sleep();
1325
1326 if (is_error_reported()) {
1327 // A fatal error has happened, the error handler(VMError::report_and_die)
1328 // should abort JVM after creating an error log file. However in some
1329 // rare cases, the error handler itself might deadlock. Here we try to
1330 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1331 //
1332 // This code is in WatcherThread because WatcherThread wakes up
1333 // periodically so the fatal error handler doesn't need to do anything;
1334 // also because the WatcherThread is less likely to crash than other
1335 // threads.
1336
1337 for (;;) {
1338 if (!ShowMessageBoxOnError
1339 && (OnError == NULL || OnError[0] == '\0')
1340 && Arguments::abort_hook() == NULL) {
1341 os::sleep(this, 2 * 60 * 1000, false);
1342 fdStream err(defaultStream::output_fd());
1343 err.print_raw_cr("# [ timer expired, abort... ]");
1344 // skip atexit/vm_exit/vm_abort hooks
1345 os::die();
1346 }
1347
1348 // Wake up 5 seconds later, the fatal handler may reset OnError or
1349 // ShowMessageBoxOnError when it is ready to abort.
1350 os::sleep(this, 5 * 1000, false);
1351 }
1352 }
1353
1354 PeriodicTask::real_time_tick(time_waited);
1355 }
1356
1357 // Signal that it is terminated
1358 {
1359 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1360 _watcher_thread = NULL;
1361 Terminator_lock->notify();
1362 }
1363
1364 // Thread destructor usually does this..
1365 ThreadLocalStorage::set_thread(NULL);
1366 }
1367
1368 void WatcherThread::start() {
1369 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1370
1371 if (watcher_thread() == NULL && _startable) {
1372 _should_terminate = false;
1373 // Create the single instance of WatcherThread
1374 new WatcherThread();
1375 }
1376 }
1377
1378 void WatcherThread::make_startable() {
1379 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1380 _startable = true;
1381 }
1382
1383 void WatcherThread::stop() {
1384 {
1385 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1386 _should_terminate = true;
1387 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1388
1389 WatcherThread* watcher = watcher_thread();
1390 if (watcher != NULL)
1391 watcher->unpark();
1392 }
1393
1394 // it is ok to take late safepoints here, if needed
1395 MutexLocker mu(Terminator_lock);
1396
1397 while(watcher_thread() != NULL) {
1398 // This wait should make safepoint checks, wait without a timeout,
1399 // and wait as a suspend-equivalent condition.
1400 //
1401 // Note: If the FlatProfiler is running, then this thread is waiting
1402 // for the WatcherThread to terminate and the WatcherThread, via the
1403 // FlatProfiler task, is waiting for the external suspend request on
1404 // this thread to complete. wait_for_ext_suspend_completion() will
1405 // eventually timeout, but that takes time. Making this wait a
1406 // suspend-equivalent condition solves that timeout problem.
1407 //
1408 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1409 Mutex::_as_suspend_equivalent_flag);
1410 }
1411 }
1412
1413 void WatcherThread::unpark() {
1414 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1415 PeriodicTask_lock->notify();
1416 }
1417
1418 void WatcherThread::print_on(outputStream* st) const {
1419 st->print("\"%s\" ", name());
1420 Thread::print_on(st);
1421 st->cr();
1422 }
1423
1424 // ======= JavaThread ========
1425
1426 // A JavaThread is a normal Java thread
1427
1428 void JavaThread::initialize() {
1429 // Initialize fields
1430
1431 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1432 set_claimed_par_id(UINT_MAX);
1433
1434 set_saved_exception_pc(NULL);
1435 set_threadObj(NULL);
1436 _anchor.clear();
1437 set_entry_point(NULL);
1438 set_jni_functions(jni_functions());
1439 set_callee_target(NULL);
1440 set_vm_result(NULL);
1441 set_vm_result_2(NULL);
1442 set_vframe_array_head(NULL);
1443 set_vframe_array_last(NULL);
1444 set_deferred_locals(NULL);
1445 set_deopt_mark(NULL);
1446 set_deopt_nmethod(NULL);
1447 clear_must_deopt_id();
1448 set_monitor_chunks(NULL);
1449 set_next(NULL);
1450 set_thread_state(_thread_new);
1451 _terminated = _not_terminated;
1452 _privileged_stack_top = NULL;
1453 _array_for_gc = NULL;
1454 _suspend_equivalent = false;
1455 _in_deopt_handler = 0;
1456 _doing_unsafe_access = false;
1457 _stack_guard_state = stack_guard_unused;
1458 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1459 _exception_pc = 0;
1460 _exception_handler_pc = 0;
1461 _is_method_handle_return = 0;
1462 _jvmti_thread_state= NULL;
1463 _should_post_on_exceptions_flag = JNI_FALSE;
1464 _jvmti_get_loaded_classes_closure = NULL;
1465 _interp_only_mode = 0;
1466 _special_runtime_exit_condition = _no_async_condition;
1467 _pending_async_exception = NULL;
1468 _thread_stat = NULL;
1469 _thread_stat = new ThreadStatistics();
1470 _blocked_on_compilation = false;
1471 _jni_active_critical = 0;
1472 _pending_jni_exception_check_fn = NULL;
1473 _do_not_unlock_if_synchronized = false;
1474 _cached_monitor_info = NULL;
1475 _parker = Parker::Allocate(this) ;
1476
1477 #ifndef PRODUCT
1478 _jmp_ring_index = 0;
1479 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1480 record_jump(NULL, NULL, NULL, 0);
1481 }
1482 #endif /* PRODUCT */
1483
1484 set_thread_profiler(NULL);
1485 if (FlatProfiler::is_active()) {
1486 // This is where we would decide to either give each thread it's own profiler
1487 // or use one global one from FlatProfiler,
1488 // or up to some count of the number of profiled threads, etc.
1489 ThreadProfiler* pp = new ThreadProfiler();
1490 pp->engage();
1491 set_thread_profiler(pp);
1492 }
1493
1494 // Setup safepoint state info for this thread
1495 ThreadSafepointState::create(this);
1496
1497 debug_only(_java_call_counter = 0);
1498
1499 // JVMTI PopFrame support
1500 _popframe_condition = popframe_inactive;
1501 _popframe_preserved_args = NULL;
1502 _popframe_preserved_args_size = 0;
1503 _frames_to_pop_failed_realloc = 0;
1504
1505 pd_initialize();
1506 }
1507
1508 #if INCLUDE_ALL_GCS
1509 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1510 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1511 #endif // INCLUDE_ALL_GCS
1512
1513 JavaThread::JavaThread(bool is_attaching_via_jni) :
1514 Thread()
1515 #if INCLUDE_ALL_GCS
1516 , _satb_mark_queue(&_satb_mark_queue_set),
1517 _dirty_card_queue(&_dirty_card_queue_set)
1518 #endif // INCLUDE_ALL_GCS
1519 {
1520 initialize();
1521 if (is_attaching_via_jni) {
1522 _jni_attach_state = _attaching_via_jni;
1523 } else {
1524 _jni_attach_state = _not_attaching_via_jni;
1525 }
1526 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1527 }
1528
1529 bool JavaThread::reguard_stack(address cur_sp) {
1530 if (_stack_guard_state != stack_guard_yellow_disabled) {
1531 return true; // Stack already guarded or guard pages not needed.
1532 }
1533
1534 if (register_stack_overflow()) {
1535 // For those architectures which have separate register and
1536 // memory stacks, we must check the register stack to see if
1537 // it has overflowed.
1538 return false;
1539 }
1540
1541 // Java code never executes within the yellow zone: the latter is only
1542 // there to provoke an exception during stack banging. If java code
1543 // is executing there, either StackShadowPages should be larger, or
1544 // some exception code in c1, c2 or the interpreter isn't unwinding
1545 // when it should.
1546 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1547
1548 enable_stack_yellow_zone();
1549 return true;
1550 }
1551
1552 bool JavaThread::reguard_stack(void) {
1553 return reguard_stack(os::current_stack_pointer());
1554 }
1555
1556
1557 void JavaThread::block_if_vm_exited() {
1558 if (_terminated == _vm_exited) {
1559 // _vm_exited is set at safepoint, and Threads_lock is never released
1560 // we will block here forever
1561 Threads_lock->lock_without_safepoint_check();
1562 ShouldNotReachHere();
1563 }
1564 }
1565
1566
1567 // Remove this ifdef when C1 is ported to the compiler interface.
1568 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1569
1570 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1571 Thread()
1572 #if INCLUDE_ALL_GCS
1573 , _satb_mark_queue(&_satb_mark_queue_set),
1574 _dirty_card_queue(&_dirty_card_queue_set)
1575 #endif // INCLUDE_ALL_GCS
1576 {
1577 if (TraceThreadEvents) {
1578 tty->print_cr("creating thread %p", this);
1579 }
1580 initialize();
1581 _jni_attach_state = _not_attaching_via_jni;
1582 set_entry_point(entry_point);
1583 // Create the native thread itself.
1584 // %note runtime_23
1585 os::ThreadType thr_type = os::java_thread;
1586 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1587 os::java_thread;
1588 os::create_thread(this, thr_type, stack_sz);
1589 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1590 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1591 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1592 // the exception consists of creating the exception object & initializing it, initialization
1593 // will leave the VM via a JavaCall and then all locks must be unlocked).
1594 //
1595 // The thread is still suspended when we reach here. Thread must be explicit started
1596 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1597 // by calling Threads:add. The reason why this is not done here, is because the thread
1598 // object must be fully initialized (take a look at JVM_Start)
1599 }
1600
1601 JavaThread::~JavaThread() {
1602 if (TraceThreadEvents) {
1603 tty->print_cr("terminate thread %p", this);
1604 }
1605
1606 // JSR166 -- return the parker to the free list
1607 Parker::Release(_parker);
1608 _parker = NULL ;
1609
1610 // Free any remaining previous UnrollBlock
1611 vframeArray* old_array = vframe_array_last();
1612
1613 if (old_array != NULL) {
1614 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1615 old_array->set_unroll_block(NULL);
1616 delete old_info;
1617 delete old_array;
1618 }
1619
1620 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1621 if (deferred != NULL) {
1622 // This can only happen if thread is destroyed before deoptimization occurs.
1623 assert(deferred->length() != 0, "empty array!");
1624 do {
1625 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1626 deferred->remove_at(0);
1627 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1628 delete dlv;
1629 } while (deferred->length() != 0);
1630 delete deferred;
1631 }
1632
1633 // All Java related clean up happens in exit
1634 ThreadSafepointState::destroy(this);
1635 if (_thread_profiler != NULL) delete _thread_profiler;
1636 if (_thread_stat != NULL) delete _thread_stat;
1637 }
1638
1639
1640 // The first routine called by a new Java thread
1641 void JavaThread::run() {
1642 // initialize thread-local alloc buffer related fields
1643 this->initialize_tlab();
1644
1645 // used to test validitity of stack trace backs
1646 this->record_base_of_stack_pointer();
1647
1648 // Record real stack base and size.
1649 this->record_stack_base_and_size();
1650
1651 // Initialize thread local storage; set before calling MutexLocker
1652 this->initialize_thread_local_storage();
1653
1654 this->create_stack_guard_pages();
1655
1656 this->cache_global_variables();
1657
1658 // Thread is now sufficient initialized to be handled by the safepoint code as being
1659 // in the VM. Change thread state from _thread_new to _thread_in_vm
1660 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1661
1662 assert(JavaThread::current() == this, "sanity check");
1663 assert(!Thread::current()->owns_locks(), "sanity check");
1664
1665 DTRACE_THREAD_PROBE(start, this);
1666
1667 // This operation might block. We call that after all safepoint checks for a new thread has
1668 // been completed.
1669 this->set_active_handles(JNIHandleBlock::allocate_block());
1670
1671 if (JvmtiExport::should_post_thread_life()) {
1672 JvmtiExport::post_thread_start(this);
1673 }
1674
1675 JFR_ONLY(Jfr::on_thread_start(this);)
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 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
1803
1804 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1805 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1806 // is deprecated anyhow.
1807 if (!is_Compiler_thread()) {
1808 int count = 3;
1809 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1810 EXCEPTION_MARK;
1811 JavaValue result(T_VOID);
1812 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1813 JavaCalls::call_virtual(&result,
1814 threadObj, thread_klass,
1815 vmSymbols::exit_method_name(),
1816 vmSymbols::void_method_signature(),
1817 THREAD);
1818 CLEAR_PENDING_EXCEPTION;
1819 }
1820 }
1821 // notify JVMTI
1822 if (JvmtiExport::should_post_thread_life()) {
1823 JvmtiExport::post_thread_end(this);
1824 }
1825
1826 // We have notified the agents that we are exiting, before we go on,
1827 // we must check for a pending external suspend request and honor it
1828 // in order to not surprise the thread that made the suspend request.
1829 while (true) {
1830 {
1831 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1832 if (!is_external_suspend()) {
1833 set_terminated(_thread_exiting);
1834 ThreadService::current_thread_exiting(this);
1835 break;
1836 }
1837 // Implied else:
1838 // Things get a little tricky here. We have a pending external
1839 // suspend request, but we are holding the SR_lock so we
1840 // can't just self-suspend. So we temporarily drop the lock
1841 // and then self-suspend.
1842 }
1843
1844 ThreadBlockInVM tbivm(this);
1845 java_suspend_self();
1846
1847 // We're done with this suspend request, but we have to loop around
1848 // and check again. Eventually we will get SR_lock without a pending
1849 // external suspend request and will be able to mark ourselves as
1850 // exiting.
1851 }
1852 // no more external suspends are allowed at this point
1853 } else {
1854 // before_exit() has already posted JVMTI THREAD_END events
1855 }
1856
1857 // Notify waiters on thread object. This has to be done after exit() is called
1858 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1859 // group should have the destroyed bit set before waiters are notified).
1860 ensure_join(this);
1861 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1862
1863 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1864 // held by this thread must be released. A detach operation must only
1865 // get here if there are no Java frames on the stack. Therefore, any
1866 // owned monitors at this point MUST be JNI-acquired monitors which are
1867 // pre-inflated and in the monitor cache.
1868 //
1869 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1870 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1871 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1872 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1873 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1874 }
1875
1876 // These things needs to be done while we are still a Java Thread. Make sure that thread
1877 // is in a consistent state, in case GC happens
1878 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1879 JFR_ONLY(Jfr::on_thread_exit(this);)
1880
1881 if (active_handles() != NULL) {
1882 JNIHandleBlock* block = active_handles();
1883 set_active_handles(NULL);
1884 JNIHandleBlock::release_block(block);
1885 }
1886
1887 if (free_handle_block() != NULL) {
1888 JNIHandleBlock* block = free_handle_block();
1889 set_free_handle_block(NULL);
1890 JNIHandleBlock::release_block(block);
1891 }
1892
1893 // These have to be removed while this is still a valid thread.
1894 remove_stack_guard_pages();
1895
1896 if (UseTLAB) {
1897 tlab().make_parsable(true); // retire TLAB
1898 }
1899
1900 if (JvmtiEnv::environments_might_exist()) {
1901 JvmtiExport::cleanup_thread(this);
1902 }
1903
1904 // We must flush any deferred card marks before removing a thread from
1905 // the list of active threads.
1906 Universe::heap()->flush_deferred_store_barrier(this);
1907 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1908
1909 #if INCLUDE_ALL_GCS
1910 // We must flush the G1-related buffers before removing a thread
1911 // from the list of active threads. We must do this after any deferred
1912 // card marks have been flushed (above) so that any entries that are
1913 // added to the thread's dirty card queue as a result are not lost.
1914 if (UseG1GC) {
1915 flush_barrier_queues();
1916 }
1917 #endif // INCLUDE_ALL_GCS
1918
1919 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1920 Threads::remove(this);
1921 }
1922
1923 #if INCLUDE_ALL_GCS
1924 // Flush G1-related queues.
1925 void JavaThread::flush_barrier_queues() {
1926 satb_mark_queue().flush();
1927 dirty_card_queue().flush();
1928 }
1929
1930 void JavaThread::initialize_queues() {
1931 assert(!SafepointSynchronize::is_at_safepoint(),
1932 "we should not be at a safepoint");
1933
1934 ObjPtrQueue& satb_queue = satb_mark_queue();
1935 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1936 // The SATB queue should have been constructed with its active
1937 // field set to false.
1938 assert(!satb_queue.is_active(), "SATB queue should not be active");
1939 assert(satb_queue.is_empty(), "SATB queue should be empty");
1940 // If we are creating the thread during a marking cycle, we should
1941 // set the active field of the SATB queue to true.
1942 if (satb_queue_set.is_active()) {
1943 satb_queue.set_active(true);
1944 }
1945
1946 DirtyCardQueue& dirty_queue = dirty_card_queue();
1947 // The dirty card queue should have been constructed with its
1948 // active field set to true.
1949 assert(dirty_queue.is_active(), "dirty card queue should be active");
1950 }
1951 #endif // INCLUDE_ALL_GCS
1952
1953 void JavaThread::cleanup_failed_attach_current_thread() {
1954 if (get_thread_profiler() != NULL) {
1955 get_thread_profiler()->disengage();
1956 ResourceMark rm;
1957 get_thread_profiler()->print(get_thread_name());
1958 }
1959
1960 if (active_handles() != NULL) {
1961 JNIHandleBlock* block = active_handles();
1962 set_active_handles(NULL);
1963 JNIHandleBlock::release_block(block);
1964 }
1965
1966 if (free_handle_block() != NULL) {
1967 JNIHandleBlock* block = free_handle_block();
1968 set_free_handle_block(NULL);
1969 JNIHandleBlock::release_block(block);
1970 }
1971
1972 // These have to be removed while this is still a valid thread.
1973 remove_stack_guard_pages();
1974
1975 if (UseTLAB) {
1976 tlab().make_parsable(true); // retire TLAB, if any
1977 }
1978
1979 #if INCLUDE_ALL_GCS
1980 if (UseG1GC) {
1981 flush_barrier_queues();
1982 }
1983 #endif // INCLUDE_ALL_GCS
1984
1985 Threads::remove(this);
1986 delete this;
1987 }
1988
1989
1990
1991
1992 JavaThread* JavaThread::active() {
1993 Thread* thread = ThreadLocalStorage::thread();
1994 assert(thread != NULL, "just checking");
1995 if (thread->is_Java_thread()) {
1996 return (JavaThread*) thread;
1997 } else {
1998 assert(thread->is_VM_thread(), "this must be a vm thread");
1999 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2000 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2001 assert(ret->is_Java_thread(), "must be a Java thread");
2002 return ret;
2003 }
2004 }
2005
2006 bool JavaThread::is_lock_owned(address adr) const {
2007 if (Thread::is_lock_owned(adr)) return true;
2008
2009 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2010 if (chunk->contains(adr)) return true;
2011 }
2012
2013 return false;
2014 }
2015
2016
2017 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2018 chunk->set_next(monitor_chunks());
2019 set_monitor_chunks(chunk);
2020 }
2021
2022 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2023 guarantee(monitor_chunks() != NULL, "must be non empty");
2024 if (monitor_chunks() == chunk) {
2025 set_monitor_chunks(chunk->next());
2026 } else {
2027 MonitorChunk* prev = monitor_chunks();
2028 while (prev->next() != chunk) prev = prev->next();
2029 prev->set_next(chunk->next());
2030 }
2031 }
2032
2033 // JVM support.
2034
2035 // Note: this function shouldn't block if it's called in
2036 // _thread_in_native_trans state (such as from
2037 // check_special_condition_for_native_trans()).
2038 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2039
2040 if (has_last_Java_frame() && has_async_condition()) {
2041 // If we are at a polling page safepoint (not a poll return)
2042 // then we must defer async exception because live registers
2043 // will be clobbered by the exception path. Poll return is
2044 // ok because the call we a returning from already collides
2045 // with exception handling registers and so there is no issue.
2046 // (The exception handling path kills call result registers but
2047 // this is ok since the exception kills the result anyway).
2048
2049 if (is_at_poll_safepoint()) {
2050 // if the code we are returning to has deoptimized we must defer
2051 // the exception otherwise live registers get clobbered on the
2052 // exception path before deoptimization is able to retrieve them.
2053 //
2054 RegisterMap map(this, false);
2055 frame caller_fr = last_frame().sender(&map);
2056 assert(caller_fr.is_compiled_frame(), "what?");
2057 if (caller_fr.is_deoptimized_frame()) {
2058 if (TraceExceptions) {
2059 ResourceMark rm;
2060 tty->print_cr("deferred async exception at compiled safepoint");
2061 }
2062 return;
2063 }
2064 }
2065 }
2066
2067 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2068 if (condition == _no_async_condition) {
2069 // Conditions have changed since has_special_runtime_exit_condition()
2070 // was called:
2071 // - if we were here only because of an external suspend request,
2072 // then that was taken care of above (or cancelled) so we are done
2073 // - if we were here because of another async request, then it has
2074 // been cleared between the has_special_runtime_exit_condition()
2075 // and now so again we are done
2076 return;
2077 }
2078
2079 // Check for pending async. exception
2080 if (_pending_async_exception != NULL) {
2081 // Only overwrite an already pending exception, if it is not a threadDeath.
2082 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2083
2084 // We cannot call Exceptions::_throw(...) here because we cannot block
2085 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2086
2087 if (TraceExceptions) {
2088 ResourceMark rm;
2089 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2090 if (has_last_Java_frame() ) {
2091 frame f = last_frame();
2092 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2093 }
2094 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2095 }
2096 _pending_async_exception = NULL;
2097 clear_has_async_exception();
2098 }
2099 }
2100
2101 if (check_unsafe_error &&
2102 condition == _async_unsafe_access_error && !has_pending_exception()) {
2103 condition = _no_async_condition; // done
2104 switch (thread_state()) {
2105 case _thread_in_vm:
2106 {
2107 JavaThread* THREAD = this;
2108 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2109 }
2110 case _thread_in_native:
2111 {
2112 ThreadInVMfromNative tiv(this);
2113 JavaThread* THREAD = this;
2114 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2115 }
2116 case _thread_in_Java:
2117 {
2118 ThreadInVMfromJava tiv(this);
2119 JavaThread* THREAD = this;
2120 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2121 }
2122 default:
2123 ShouldNotReachHere();
2124 }
2125 }
2126
2127 assert(condition == _no_async_condition || has_pending_exception() ||
2128 (!check_unsafe_error && condition == _async_unsafe_access_error),
2129 "must have handled the async condition, if no exception");
2130 }
2131
2132 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2133 //
2134 // Check for pending external suspend. Internal suspend requests do
2135 // not use handle_special_runtime_exit_condition().
2136 // If JNIEnv proxies are allowed, don't self-suspend if the target
2137 // thread is not the current thread. In older versions of jdbx, jdbx
2138 // threads could call into the VM with another thread's JNIEnv so we
2139 // can be here operating on behalf of a suspended thread (4432884).
2140 bool do_self_suspend = is_external_suspend_with_lock();
2141 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2142 //
2143 // Because thread is external suspended the safepoint code will count
2144 // thread as at a safepoint. This can be odd because we can be here
2145 // as _thread_in_Java which would normally transition to _thread_blocked
2146 // at a safepoint. We would like to mark the thread as _thread_blocked
2147 // before calling java_suspend_self like all other callers of it but
2148 // we must then observe proper safepoint protocol. (We can't leave
2149 // _thread_blocked with a safepoint in progress). However we can be
2150 // here as _thread_in_native_trans so we can't use a normal transition
2151 // constructor/destructor pair because they assert on that type of
2152 // transition. We could do something like:
2153 //
2154 // JavaThreadState state = thread_state();
2155 // set_thread_state(_thread_in_vm);
2156 // {
2157 // ThreadBlockInVM tbivm(this);
2158 // java_suspend_self()
2159 // }
2160 // set_thread_state(_thread_in_vm_trans);
2161 // if (safepoint) block;
2162 // set_thread_state(state);
2163 //
2164 // but that is pretty messy. Instead we just go with the way the
2165 // code has worked before and note that this is the only path to
2166 // java_suspend_self that doesn't put the thread in _thread_blocked
2167 // mode.
2168
2169 frame_anchor()->make_walkable(this);
2170 java_suspend_self();
2171
2172 // We might be here for reasons in addition to the self-suspend request
2173 // so check for other async requests.
2174 }
2175
2176 if (check_asyncs) {
2177 check_and_handle_async_exceptions();
2178 }
2179
2180 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2181 }
2182
2183 void JavaThread::send_thread_stop(oop java_throwable) {
2184 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2185 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2186 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2187
2188 // Do not throw asynchronous exceptions against the compiler thread
2189 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2190 if (is_Compiler_thread()) return;
2191
2192 {
2193 // Actually throw the Throwable against the target Thread - however
2194 // only if there is no thread death exception installed already.
2195 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2196 // If the topmost frame is a runtime stub, then we are calling into
2197 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2198 // must deoptimize the caller before continuing, as the compiled exception handler table
2199 // may not be valid
2200 if (has_last_Java_frame()) {
2201 frame f = last_frame();
2202 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2203 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2204 RegisterMap reg_map(this, UseBiasedLocking);
2205 frame compiled_frame = f.sender(®_map);
2206 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2207 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2208 }
2209 }
2210 }
2211
2212 // Set async. pending exception in thread.
2213 set_pending_async_exception(java_throwable);
2214
2215 if (TraceExceptions) {
2216 ResourceMark rm;
2217 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2218 }
2219 // for AbortVMOnException flag
2220 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2221 }
2222 }
2223
2224
2225 // Interrupt thread so it will wake up from a potential wait()
2226 Thread::interrupt(this);
2227 }
2228
2229 // External suspension mechanism.
2230 //
2231 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2232 // to any VM_locks and it is at a transition
2233 // Self-suspension will happen on the transition out of the vm.
2234 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2235 //
2236 // Guarantees on return:
2237 // + Target thread will not execute any new bytecode (that's why we need to
2238 // force a safepoint)
2239 // + Target thread will not enter any new monitors
2240 //
2241 void JavaThread::java_suspend() {
2242 { MutexLocker mu(Threads_lock);
2243 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2244 return;
2245 }
2246 }
2247
2248 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2249 if (!is_external_suspend()) {
2250 // a racing resume has cancelled us; bail out now
2251 return;
2252 }
2253
2254 // suspend is done
2255 uint32_t debug_bits = 0;
2256 // Warning: is_ext_suspend_completed() may temporarily drop the
2257 // SR_lock to allow the thread to reach a stable thread state if
2258 // it is currently in a transient thread state.
2259 if (is_ext_suspend_completed(false /* !called_by_wait */,
2260 SuspendRetryDelay, &debug_bits) ) {
2261 return;
2262 }
2263 }
2264
2265 VM_ForceSafepoint vm_suspend;
2266 VMThread::execute(&vm_suspend);
2267 }
2268
2269 // Part II of external suspension.
2270 // A JavaThread self suspends when it detects a pending external suspend
2271 // request. This is usually on transitions. It is also done in places
2272 // where continuing to the next transition would surprise the caller,
2273 // e.g., monitor entry.
2274 //
2275 // Returns the number of times that the thread self-suspended.
2276 //
2277 // Note: DO NOT call java_suspend_self() when you just want to block current
2278 // thread. java_suspend_self() is the second stage of cooperative
2279 // suspension for external suspend requests and should only be used
2280 // to complete an external suspend request.
2281 //
2282 int JavaThread::java_suspend_self() {
2283 int ret = 0;
2284
2285 // we are in the process of exiting so don't suspend
2286 if (is_exiting()) {
2287 clear_external_suspend();
2288 return ret;
2289 }
2290
2291 assert(_anchor.walkable() ||
2292 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2293 "must have walkable stack");
2294
2295 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2296
2297 assert(!this->is_ext_suspended(),
2298 "a thread trying to self-suspend should not already be suspended");
2299
2300 if (this->is_suspend_equivalent()) {
2301 // If we are self-suspending as a result of the lifting of a
2302 // suspend equivalent condition, then the suspend_equivalent
2303 // flag is not cleared until we set the ext_suspended flag so
2304 // that wait_for_ext_suspend_completion() returns consistent
2305 // results.
2306 this->clear_suspend_equivalent();
2307 }
2308
2309 // A racing resume may have cancelled us before we grabbed SR_lock
2310 // above. Or another external suspend request could be waiting for us
2311 // by the time we return from SR_lock()->wait(). The thread
2312 // that requested the suspension may already be trying to walk our
2313 // stack and if we return now, we can change the stack out from under
2314 // it. This would be a "bad thing (TM)" and cause the stack walker
2315 // to crash. We stay self-suspended until there are no more pending
2316 // external suspend requests.
2317 while (is_external_suspend()) {
2318 ret++;
2319 this->set_ext_suspended();
2320
2321 // _ext_suspended flag is cleared by java_resume()
2322 while (is_ext_suspended()) {
2323 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2324 }
2325 }
2326
2327 return ret;
2328 }
2329
2330 #ifdef ASSERT
2331 // verify the JavaThread has not yet been published in the Threads::list, and
2332 // hence doesn't need protection from concurrent access at this stage
2333 void JavaThread::verify_not_published() {
2334 if (!Threads_lock->owned_by_self()) {
2335 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2336 assert( !Threads::includes(this),
2337 "java thread shouldn't have been published yet!");
2338 }
2339 else {
2340 assert( !Threads::includes(this),
2341 "java thread shouldn't have been published yet!");
2342 }
2343 }
2344 #endif
2345
2346 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2347 // progress or when _suspend_flags is non-zero.
2348 // Current thread needs to self-suspend if there is a suspend request and/or
2349 // block if a safepoint is in progress.
2350 // Async exception ISN'T checked.
2351 // Note only the ThreadInVMfromNative transition can call this function
2352 // directly and when thread state is _thread_in_native_trans
2353 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2354 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2355
2356 JavaThread *curJT = JavaThread::current();
2357 bool do_self_suspend = thread->is_external_suspend();
2358
2359 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2360
2361 // If JNIEnv proxies are allowed, don't self-suspend if the target
2362 // thread is not the current thread. In older versions of jdbx, jdbx
2363 // threads could call into the VM with another thread's JNIEnv so we
2364 // can be here operating on behalf of a suspended thread (4432884).
2365 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2366 JavaThreadState state = thread->thread_state();
2367
2368 // We mark this thread_blocked state as a suspend-equivalent so
2369 // that a caller to is_ext_suspend_completed() won't be confused.
2370 // The suspend-equivalent state is cleared by java_suspend_self().
2371 thread->set_suspend_equivalent();
2372
2373 // If the safepoint code sees the _thread_in_native_trans state, it will
2374 // wait until the thread changes to other thread state. There is no
2375 // guarantee on how soon we can obtain the SR_lock and complete the
2376 // self-suspend request. It would be a bad idea to let safepoint wait for
2377 // too long. Temporarily change the state to _thread_blocked to
2378 // let the VM thread know that this thread is ready for GC. The problem
2379 // of changing thread state is that safepoint could happen just after
2380 // java_suspend_self() returns after being resumed, and VM thread will
2381 // see the _thread_blocked state. We must check for safepoint
2382 // after restoring the state and make sure we won't leave while a safepoint
2383 // is in progress.
2384 thread->set_thread_state(_thread_blocked);
2385 thread->java_suspend_self();
2386 thread->set_thread_state(state);
2387 // Make sure new state is seen by VM thread
2388 if (os::is_MP()) {
2389 if (UseMembar) {
2390 // Force a fence between the write above and read below
2391 OrderAccess::fence();
2392 } else {
2393 // Must use this rather than serialization page in particular on Windows
2394 InterfaceSupport::serialize_memory(thread);
2395 }
2396 }
2397 }
2398
2399 if (SafepointSynchronize::do_call_back()) {
2400 // If we are safepointing, then block the caller which may not be
2401 // the same as the target thread (see above).
2402 SafepointSynchronize::block(curJT);
2403 }
2404
2405 if (thread->is_deopt_suspend()) {
2406 thread->clear_deopt_suspend();
2407 RegisterMap map(thread, false);
2408 frame f = thread->last_frame();
2409 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2410 f = f.sender(&map);
2411 }
2412 if (f.id() == thread->must_deopt_id()) {
2413 thread->clear_must_deopt_id();
2414 f.deoptimize(thread);
2415 } else {
2416 fatal("missed deoptimization!");
2417 }
2418 }
2419
2420 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2421 }
2422
2423 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2424 // progress or when _suspend_flags is non-zero.
2425 // Current thread needs to self-suspend if there is a suspend request and/or
2426 // block if a safepoint is in progress.
2427 // Also check for pending async exception (not including unsafe access error).
2428 // Note only the native==>VM/Java barriers can call this function and when
2429 // thread state is _thread_in_native_trans.
2430 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2431 check_safepoint_and_suspend_for_native_trans(thread);
2432
2433 if (thread->has_async_exception()) {
2434 // We are in _thread_in_native_trans state, don't handle unsafe
2435 // access error since that may block.
2436 thread->check_and_handle_async_exceptions(false);
2437 }
2438 }
2439
2440 // This is a variant of the normal
2441 // check_special_condition_for_native_trans with slightly different
2442 // semantics for use by critical native wrappers. It does all the
2443 // normal checks but also performs the transition back into
2444 // thread_in_Java state. This is required so that critical natives
2445 // can potentially block and perform a GC if they are the last thread
2446 // exiting the GC_locker.
2447 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2448 check_special_condition_for_native_trans(thread);
2449
2450 // Finish the transition
2451 thread->set_thread_state(_thread_in_Java);
2452
2453 if (thread->do_critical_native_unlock()) {
2454 ThreadInVMfromJavaNoAsyncException tiv(thread);
2455 GC_locker::unlock_critical(thread);
2456 thread->clear_critical_native_unlock();
2457 }
2458 }
2459
2460 // We need to guarantee the Threads_lock here, since resumes are not
2461 // allowed during safepoint synchronization
2462 // Can only resume from an external suspension
2463 void JavaThread::java_resume() {
2464 assert_locked_or_safepoint(Threads_lock);
2465
2466 // Sanity check: thread is gone, has started exiting or the thread
2467 // was not externally suspended.
2468 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2469 return;
2470 }
2471
2472 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2473
2474 clear_external_suspend();
2475
2476 if (is_ext_suspended()) {
2477 clear_ext_suspended();
2478 SR_lock()->notify_all();
2479 }
2480 }
2481
2482 void JavaThread::create_stack_guard_pages() {
2483 if (!os::uses_stack_guard_pages() ||
2484 _stack_guard_state != stack_guard_unused ||
2485 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2486 if (TraceThreadEvents) {
2487 tty->print_cr("Stack guard page creation for thread "
2488 UINTX_FORMAT " disabled", os::current_thread_id());
2489 }
2490 return;
2491 }
2492 address low_addr = stack_base() - stack_size();
2493 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2494
2495 int allocate = os::allocate_stack_guard_pages();
2496 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2497
2498 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2499 warning("Attempt to allocate stack guard pages failed.");
2500 return;
2501 }
2502
2503 if (os::guard_memory((char *) low_addr, len)) {
2504 _stack_guard_state = stack_guard_enabled;
2505 } else {
2506 warning("Attempt to protect stack guard pages failed.");
2507 if (os::uncommit_memory((char *) low_addr, len)) {
2508 warning("Attempt to deallocate stack guard pages failed.");
2509 }
2510 }
2511 }
2512
2513 void JavaThread::remove_stack_guard_pages() {
2514 assert(Thread::current() == this, "from different thread");
2515 if (_stack_guard_state == stack_guard_unused) return;
2516 address low_addr = stack_base() - stack_size();
2517 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2518
2519 if (os::allocate_stack_guard_pages()) {
2520 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2521 _stack_guard_state = stack_guard_unused;
2522 } else {
2523 warning("Attempt to deallocate stack guard pages failed.");
2524 }
2525 } else {
2526 if (_stack_guard_state == stack_guard_unused) return;
2527 if (os::unguard_memory((char *) low_addr, len)) {
2528 _stack_guard_state = stack_guard_unused;
2529 } else {
2530 warning("Attempt to unprotect stack guard pages failed.");
2531 }
2532 }
2533 }
2534
2535 void JavaThread::enable_stack_yellow_zone() {
2536 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2537 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2538
2539 // The base notation is from the stacks point of view, growing downward.
2540 // We need to adjust it to work correctly with guard_memory()
2541 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2542
2543 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2544 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2545
2546 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2547 _stack_guard_state = stack_guard_enabled;
2548 } else {
2549 warning("Attempt to guard stack yellow zone failed.");
2550 }
2551 enable_register_stack_guard();
2552 }
2553
2554 void JavaThread::disable_stack_yellow_zone() {
2555 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2556 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2557
2558 // Simply return if called for a thread that does not use guard pages.
2559 if (_stack_guard_state == stack_guard_unused) return;
2560
2561 // The base notation is from the stacks point of view, growing downward.
2562 // We need to adjust it to work correctly with guard_memory()
2563 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2564
2565 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2566 _stack_guard_state = stack_guard_yellow_disabled;
2567 } else {
2568 warning("Attempt to unguard stack yellow zone failed.");
2569 }
2570 disable_register_stack_guard();
2571 }
2572
2573 void JavaThread::enable_stack_red_zone() {
2574 // The base notation is from the stacks point of view, growing downward.
2575 // We need to adjust it to work correctly with guard_memory()
2576 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2577 address base = stack_red_zone_base() - stack_red_zone_size();
2578
2579 guarantee(base < stack_base(),"Error calculating stack red zone");
2580 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2581
2582 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2583 warning("Attempt to guard stack red zone failed.");
2584 }
2585 }
2586
2587 void JavaThread::disable_stack_red_zone() {
2588 // The base notation is from the stacks point of view, growing downward.
2589 // We need to adjust it to work correctly with guard_memory()
2590 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2591 address base = stack_red_zone_base() - stack_red_zone_size();
2592 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2593 warning("Attempt to unguard stack red zone failed.");
2594 }
2595 }
2596
2597 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2598 // ignore is there is no stack
2599 if (!has_last_Java_frame()) return;
2600 // traverse the stack frames. Starts from top frame.
2601 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2602 frame* fr = fst.current();
2603 f(fr, fst.register_map());
2604 }
2605 }
2606
2607
2608 #ifndef PRODUCT
2609 // Deoptimization
2610 // Function for testing deoptimization
2611 void JavaThread::deoptimize() {
2612 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2613 StackFrameStream fst(this, UseBiasedLocking);
2614 bool deopt = false; // Dump stack only if a deopt actually happens.
2615 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2616 // Iterate over all frames in the thread and deoptimize
2617 for(; !fst.is_done(); fst.next()) {
2618 if(fst.current()->can_be_deoptimized()) {
2619
2620 if (only_at) {
2621 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2622 // consists of comma or carriage return separated numbers so
2623 // search for the current bci in that string.
2624 address pc = fst.current()->pc();
2625 nmethod* nm = (nmethod*) fst.current()->cb();
2626 ScopeDesc* sd = nm->scope_desc_at( pc);
2627 char buffer[8];
2628 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2629 size_t len = strlen(buffer);
2630 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2631 while (found != NULL) {
2632 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2633 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2634 // Check that the bci found is bracketed by terminators.
2635 break;
2636 }
2637 found = strstr(found + 1, buffer);
2638 }
2639 if (!found) {
2640 continue;
2641 }
2642 }
2643
2644 if (DebugDeoptimization && !deopt) {
2645 deopt = true; // One-time only print before deopt
2646 tty->print_cr("[BEFORE Deoptimization]");
2647 trace_frames();
2648 trace_stack();
2649 }
2650 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2651 }
2652 }
2653
2654 if (DebugDeoptimization && deopt) {
2655 tty->print_cr("[AFTER Deoptimization]");
2656 trace_frames();
2657 }
2658 }
2659
2660
2661 // Make zombies
2662 void JavaThread::make_zombies() {
2663 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2664 if (fst.current()->can_be_deoptimized()) {
2665 // it is a Java nmethod
2666 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2667 nm->make_not_entrant();
2668 }
2669 }
2670 }
2671 #endif // PRODUCT
2672
2673
2674 void JavaThread::deoptimized_wrt_marked_nmethods() {
2675 if (!has_last_Java_frame()) return;
2676 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2677 StackFrameStream fst(this, UseBiasedLocking);
2678 for(; !fst.is_done(); fst.next()) {
2679 if (fst.current()->should_be_deoptimized()) {
2680 if (LogCompilation && xtty != NULL) {
2681 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2682 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2683 this->name(), nm != NULL ? nm->compile_id() : -1);
2684 }
2685
2686 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2687 }
2688 }
2689 }
2690
2691
2692 // GC support
2693 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2694
2695 void JavaThread::gc_epilogue() {
2696 frames_do(frame_gc_epilogue);
2697 }
2698
2699
2700 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2701
2702 void JavaThread::gc_prologue() {
2703 frames_do(frame_gc_prologue);
2704 }
2705
2706 // If the caller is a NamedThread, then remember, in the current scope,
2707 // the given JavaThread in its _processed_thread field.
2708 class RememberProcessedThread: public StackObj {
2709 NamedThread* _cur_thr;
2710 public:
2711 RememberProcessedThread(JavaThread* jthr) {
2712 Thread* thread = Thread::current();
2713 if (thread->is_Named_thread()) {
2714 _cur_thr = (NamedThread *)thread;
2715 _cur_thr->set_processed_thread(jthr);
2716 } else {
2717 _cur_thr = NULL;
2718 }
2719 }
2720
2721 ~RememberProcessedThread() {
2722 if (_cur_thr) {
2723 _cur_thr->set_processed_thread(NULL);
2724 }
2725 }
2726 };
2727
2728 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2729 // Verify that the deferred card marks have been flushed.
2730 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2731
2732 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2733 // since there may be more than one thread using each ThreadProfiler.
2734
2735 // Traverse the GCHandles
2736 Thread::oops_do(f, cld_f, cf);
2737
2738 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2739 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2740
2741 if (has_last_Java_frame()) {
2742 // Record JavaThread to GC thread
2743 RememberProcessedThread rpt(this);
2744
2745 // Traverse the privileged stack
2746 if (_privileged_stack_top != NULL) {
2747 _privileged_stack_top->oops_do(f);
2748 }
2749
2750 // traverse the registered growable array
2751 if (_array_for_gc != NULL) {
2752 for (int index = 0; index < _array_for_gc->length(); index++) {
2753 f->do_oop(_array_for_gc->adr_at(index));
2754 }
2755 }
2756
2757 // Traverse the monitor chunks
2758 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2759 chunk->oops_do(f);
2760 }
2761
2762 // Traverse the execution stack
2763 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2764 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2765 }
2766 }
2767
2768 // callee_target is never live across a gc point so NULL it here should
2769 // it still contain a methdOop.
2770
2771 set_callee_target(NULL);
2772
2773 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2774 // If we have deferred set_locals there might be oops waiting to be
2775 // written
2776 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2777 if (list != NULL) {
2778 for (int i = 0; i < list->length(); i++) {
2779 list->at(i)->oops_do(f);
2780 }
2781 }
2782
2783 // Traverse instance variables at the end since the GC may be moving things
2784 // around using this function
2785 f->do_oop((oop*) &_threadObj);
2786 f->do_oop((oop*) &_vm_result);
2787 f->do_oop((oop*) &_exception_oop);
2788 f->do_oop((oop*) &_pending_async_exception);
2789
2790 if (jvmti_thread_state() != NULL) {
2791 jvmti_thread_state()->oops_do(f);
2792 }
2793 }
2794
2795 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2796 Thread::nmethods_do(cf); // (super method is a no-op)
2797
2798 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2799 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2800
2801 if (has_last_Java_frame()) {
2802 // Traverse the execution stack
2803 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2804 fst.current()->nmethods_do(cf);
2805 }
2806 }
2807 }
2808
2809 void JavaThread::metadata_do(void f(Metadata*)) {
2810 Thread::metadata_do(f);
2811 if (has_last_Java_frame()) {
2812 // Traverse the execution stack to call f() on the methods in the stack
2813 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2814 fst.current()->metadata_do(f);
2815 }
2816 } else if (is_Compiler_thread()) {
2817 // need to walk ciMetadata in current compile tasks to keep alive.
2818 CompilerThread* ct = (CompilerThread*)this;
2819 if (ct->env() != NULL) {
2820 ct->env()->metadata_do(f);
2821 }
2822 }
2823 }
2824
2825 // Printing
2826 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2827 switch (_thread_state) {
2828 case _thread_uninitialized: return "_thread_uninitialized";
2829 case _thread_new: return "_thread_new";
2830 case _thread_new_trans: return "_thread_new_trans";
2831 case _thread_in_native: return "_thread_in_native";
2832 case _thread_in_native_trans: return "_thread_in_native_trans";
2833 case _thread_in_vm: return "_thread_in_vm";
2834 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2835 case _thread_in_Java: return "_thread_in_Java";
2836 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2837 case _thread_blocked: return "_thread_blocked";
2838 case _thread_blocked_trans: return "_thread_blocked_trans";
2839 default: return "unknown thread state";
2840 }
2841 }
2842
2843 #ifndef PRODUCT
2844 void JavaThread::print_thread_state_on(outputStream *st) const {
2845 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2846 };
2847 void JavaThread::print_thread_state() const {
2848 print_thread_state_on(tty);
2849 };
2850 #endif // PRODUCT
2851
2852 // Called by Threads::print() for VM_PrintThreads operation
2853 void JavaThread::print_on(outputStream *st) const {
2854 st->print("\"%s\" ", get_thread_name());
2855 oop thread_oop = threadObj();
2856 if (thread_oop != NULL) {
2857 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2858 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2859 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2860 }
2861 Thread::print_on(st);
2862 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2863 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2864 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2865 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2866 }
2867 #ifndef PRODUCT
2868 print_thread_state_on(st);
2869 _safepoint_state->print_on(st);
2870 #endif // PRODUCT
2871 }
2872
2873 // Called by fatal error handler. The difference between this and
2874 // JavaThread::print() is that we can't grab lock or allocate memory.
2875 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2876 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2877 oop thread_obj = threadObj();
2878 if (thread_obj != NULL) {
2879 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2880 }
2881 st->print(" [");
2882 st->print("%s", _get_thread_state_name(_thread_state));
2883 if (osthread()) {
2884 st->print(", id=%d", osthread()->thread_id());
2885 }
2886 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2887 _stack_base - _stack_size, _stack_base);
2888 st->print("]");
2889 return;
2890 }
2891
2892 // Verification
2893
2894 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2895
2896 void JavaThread::verify() {
2897 // Verify oops in the thread.
2898 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2899
2900 // Verify the stack frames.
2901 frames_do(frame_verify);
2902 }
2903
2904 // CR 6300358 (sub-CR 2137150)
2905 // Most callers of this method assume that it can't return NULL but a
2906 // thread may not have a name whilst it is in the process of attaching to
2907 // the VM - see CR 6412693, and there are places where a JavaThread can be
2908 // seen prior to having it's threadObj set (eg JNI attaching threads and
2909 // if vm exit occurs during initialization). These cases can all be accounted
2910 // for such that this method never returns NULL.
2911 const char* JavaThread::get_thread_name() const {
2912 #ifdef ASSERT
2913 // early safepoints can hit while current thread does not yet have TLS
2914 if (!SafepointSynchronize::is_at_safepoint()) {
2915 Thread *cur = Thread::current();
2916 if (!(cur->is_Java_thread() && cur == this)) {
2917 // Current JavaThreads are allowed to get their own name without
2918 // the Threads_lock.
2919 assert_locked_or_safepoint(Threads_lock);
2920 }
2921 }
2922 #endif // ASSERT
2923 return get_thread_name_string();
2924 }
2925
2926 // Returns a non-NULL representation of this thread's name, or a suitable
2927 // descriptive string if there is no set name
2928 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2929 const char* name_str;
2930 oop thread_obj = threadObj();
2931 if (thread_obj != NULL) {
2932 oop name = java_lang_Thread::name(thread_obj);
2933 if (name != NULL) {
2934 if (buf == NULL) {
2935 name_str = java_lang_String::as_utf8_string(name);
2936 }
2937 else {
2938 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2939 }
2940 }
2941 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2942 name_str = "<no-name - thread is attaching>";
2943 }
2944 else {
2945 name_str = Thread::name();
2946 }
2947 }
2948 else {
2949 name_str = Thread::name();
2950 }
2951 assert(name_str != NULL, "unexpected NULL thread name");
2952 return name_str;
2953 }
2954
2955
2956 const char* JavaThread::get_threadgroup_name() const {
2957 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2958 oop thread_obj = threadObj();
2959 if (thread_obj != NULL) {
2960 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2961 if (thread_group != NULL) {
2962 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2963 // ThreadGroup.name can be null
2964 if (name != NULL) {
2965 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2966 return str;
2967 }
2968 }
2969 }
2970 return NULL;
2971 }
2972
2973 const char* JavaThread::get_parent_name() const {
2974 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2975 oop thread_obj = threadObj();
2976 if (thread_obj != NULL) {
2977 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2978 if (thread_group != NULL) {
2979 oop parent = java_lang_ThreadGroup::parent(thread_group);
2980 if (parent != NULL) {
2981 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2982 // ThreadGroup.name can be null
2983 if (name != NULL) {
2984 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2985 return str;
2986 }
2987 }
2988 }
2989 }
2990 return NULL;
2991 }
2992
2993 ThreadPriority JavaThread::java_priority() const {
2994 oop thr_oop = threadObj();
2995 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2996 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2997 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2998 return priority;
2999 }
3000
3001 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3002
3003 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3004 // Link Java Thread object <-> C++ Thread
3005
3006 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3007 // and put it into a new Handle. The Handle "thread_oop" can then
3008 // be used to pass the C++ thread object to other methods.
3009
3010 // Set the Java level thread object (jthread) field of the
3011 // new thread (a JavaThread *) to C++ thread object using the
3012 // "thread_oop" handle.
3013
3014 // Set the thread field (a JavaThread *) of the
3015 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3016
3017 Handle thread_oop(Thread::current(),
3018 JNIHandles::resolve_non_null(jni_thread));
3019 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3020 "must be initialized");
3021 set_threadObj(thread_oop());
3022 java_lang_Thread::set_thread(thread_oop(), this);
3023
3024 if (prio == NoPriority) {
3025 prio = java_lang_Thread::priority(thread_oop());
3026 assert(prio != NoPriority, "A valid priority should be present");
3027 }
3028
3029 // Push the Java priority down to the native thread; needs Threads_lock
3030 Thread::set_priority(this, prio);
3031
3032 prepare_ext();
3033
3034 // Add the new thread to the Threads list and set it in motion.
3035 // We must have threads lock in order to call Threads::add.
3036 // It is crucial that we do not block before the thread is
3037 // added to the Threads list for if a GC happens, then the java_thread oop
3038 // will not be visited by GC.
3039 Threads::add(this);
3040 }
3041
3042 oop JavaThread::current_park_blocker() {
3043 // Support for JSR-166 locks
3044 oop thread_oop = threadObj();
3045 if (thread_oop != NULL &&
3046 JDK_Version::current().supports_thread_park_blocker()) {
3047 return java_lang_Thread::park_blocker(thread_oop);
3048 }
3049 return NULL;
3050 }
3051
3052
3053 void JavaThread::print_stack_on(outputStream* st) {
3054 if (!has_last_Java_frame()) return;
3055 ResourceMark rm;
3056 HandleMark hm;
3057
3058 RegisterMap reg_map(this);
3059 vframe* start_vf = last_java_vframe(®_map);
3060 int count = 0;
3061 for (vframe* f = start_vf; f; f = f->sender() ) {
3062 if (f->is_java_frame()) {
3063 javaVFrame* jvf = javaVFrame::cast(f);
3064 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3065
3066 // Print out lock information
3067 if (JavaMonitorsInStackTrace) {
3068 jvf->print_lock_info_on(st, count);
3069 }
3070 } else {
3071 // Ignore non-Java frames
3072 }
3073
3074 // Bail-out case for too deep stacks
3075 count++;
3076 if (MaxJavaStackTraceDepth == count) return;
3077 }
3078 }
3079
3080
3081 // JVMTI PopFrame support
3082 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3083 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3084 if (in_bytes(size_in_bytes) != 0) {
3085 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3086 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3087 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3088 }
3089 }
3090
3091 void* JavaThread::popframe_preserved_args() {
3092 return _popframe_preserved_args;
3093 }
3094
3095 ByteSize JavaThread::popframe_preserved_args_size() {
3096 return in_ByteSize(_popframe_preserved_args_size);
3097 }
3098
3099 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3100 int sz = in_bytes(popframe_preserved_args_size());
3101 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3102 return in_WordSize(sz / wordSize);
3103 }
3104
3105 void JavaThread::popframe_free_preserved_args() {
3106 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3107 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3108 _popframe_preserved_args = NULL;
3109 _popframe_preserved_args_size = 0;
3110 }
3111
3112 #ifndef PRODUCT
3113
3114 void JavaThread::trace_frames() {
3115 tty->print_cr("[Describe stack]");
3116 int frame_no = 1;
3117 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3118 tty->print(" %d. ", frame_no++);
3119 fst.current()->print_value_on(tty,this);
3120 tty->cr();
3121 }
3122 }
3123
3124 class PrintAndVerifyOopClosure: public OopClosure {
3125 protected:
3126 template <class T> inline void do_oop_work(T* p) {
3127 oop obj = oopDesc::load_decode_heap_oop(p);
3128 if (obj == NULL) return;
3129 tty->print(INTPTR_FORMAT ": ", p);
3130 if (obj->is_oop_or_null()) {
3131 if (obj->is_objArray()) {
3132 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3133 } else {
3134 obj->print();
3135 }
3136 } else {
3137 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3138 }
3139 tty->cr();
3140 }
3141 public:
3142 virtual void do_oop(oop* p) { do_oop_work(p); }
3143 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3144 };
3145
3146
3147 static void oops_print(frame* f, const RegisterMap *map) {
3148 PrintAndVerifyOopClosure print;
3149 f->print_value();
3150 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3151 }
3152
3153 // Print our all the locations that contain oops and whether they are
3154 // valid or not. This useful when trying to find the oldest frame
3155 // where an oop has gone bad since the frame walk is from youngest to
3156 // oldest.
3157 void JavaThread::trace_oops() {
3158 tty->print_cr("[Trace oops]");
3159 frames_do(oops_print);
3160 }
3161
3162
3163 #ifdef ASSERT
3164 // Print or validate the layout of stack frames
3165 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3166 ResourceMark rm;
3167 PRESERVE_EXCEPTION_MARK;
3168 FrameValues values;
3169 int frame_no = 0;
3170 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3171 fst.current()->describe(values, ++frame_no);
3172 if (depth == frame_no) break;
3173 }
3174 if (validate_only) {
3175 values.validate();
3176 } else {
3177 tty->print_cr("[Describe stack layout]");
3178 values.print(this);
3179 }
3180 }
3181 #endif
3182
3183 void JavaThread::trace_stack_from(vframe* start_vf) {
3184 ResourceMark rm;
3185 int vframe_no = 1;
3186 for (vframe* f = start_vf; f; f = f->sender() ) {
3187 if (f->is_java_frame()) {
3188 javaVFrame::cast(f)->print_activation(vframe_no++);
3189 } else {
3190 f->print();
3191 }
3192 if (vframe_no > StackPrintLimit) {
3193 tty->print_cr("...<more frames>...");
3194 return;
3195 }
3196 }
3197 }
3198
3199
3200 void JavaThread::trace_stack() {
3201 if (!has_last_Java_frame()) return;
3202 ResourceMark rm;
3203 HandleMark hm;
3204 RegisterMap reg_map(this);
3205 trace_stack_from(last_java_vframe(®_map));
3206 }
3207
3208
3209 #endif // PRODUCT
3210
3211
3212 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3213 assert(reg_map != NULL, "a map must be given");
3214 frame f = last_frame();
3215 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3216 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3217 }
3218 return NULL;
3219 }
3220
3221
3222 Klass* JavaThread::security_get_caller_class(int depth) {
3223 vframeStream vfst(this);
3224 vfst.security_get_caller_frame(depth);
3225 if (!vfst.at_end()) {
3226 return vfst.method()->method_holder();
3227 }
3228 return NULL;
3229 }
3230
3231 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3232 assert(thread->is_Compiler_thread(), "must be compiler thread");
3233 CompileBroker::compiler_thread_loop();
3234 }
3235
3236 // Create a CompilerThread
3237 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3238 : JavaThread(&compiler_thread_entry) {
3239 _env = NULL;
3240 _log = NULL;
3241 _task = NULL;
3242 _queue = queue;
3243 _counters = counters;
3244 _buffer_blob = NULL;
3245 _scanned_nmethod = NULL;
3246 _compiler = NULL;
3247
3248 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3249 resource_area()->bias_to(mtCompiler);
3250
3251 #ifndef PRODUCT
3252 _ideal_graph_printer = NULL;
3253 #endif
3254 }
3255
3256 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3257 JavaThread::oops_do(f, cld_f, cf);
3258 if (_scanned_nmethod != NULL && cf != NULL) {
3259 // Safepoints can occur when the sweeper is scanning an nmethod so
3260 // process it here to make sure it isn't unloaded in the middle of
3261 // a scan.
3262 cf->do_code_blob(_scanned_nmethod);
3263 }
3264 }
3265
3266
3267 // ======= Threads ========
3268
3269 // The Threads class links together all active threads, and provides
3270 // operations over all threads. It is protected by its own Mutex
3271 // lock, which is also used in other contexts to protect thread
3272 // operations from having the thread being operated on from exiting
3273 // and going away unexpectedly (e.g., safepoint synchronization)
3274
3275 JavaThread* Threads::_thread_list = NULL;
3276 int Threads::_number_of_threads = 0;
3277 int Threads::_number_of_non_daemon_threads = 0;
3278 int Threads::_return_code = 0;
3279 size_t JavaThread::_stack_size_at_create = 0;
3280 #ifdef ASSERT
3281 bool Threads::_vm_complete = false;
3282 #endif
3283
3284 // All JavaThreads
3285 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3286
3287 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3288 void Threads::threads_do(ThreadClosure* tc) {
3289 assert_locked_or_safepoint(Threads_lock);
3290 // ALL_JAVA_THREADS iterates through all JavaThreads
3291 ALL_JAVA_THREADS(p) {
3292 tc->do_thread(p);
3293 }
3294 // Someday we could have a table or list of all non-JavaThreads.
3295 // For now, just manually iterate through them.
3296 tc->do_thread(VMThread::vm_thread());
3297 Universe::heap()->gc_threads_do(tc);
3298 WatcherThread *wt = WatcherThread::watcher_thread();
3299 // Strictly speaking, the following NULL check isn't sufficient to make sure
3300 // the data for WatcherThread is still valid upon being examined. However,
3301 // considering that WatchThread terminates when the VM is on the way to
3302 // exit at safepoint, the chance of the above is extremely small. The right
3303 // way to prevent termination of WatcherThread would be to acquire
3304 // Terminator_lock, but we can't do that without violating the lock rank
3305 // checking in some cases.
3306 if (wt != NULL)
3307 tc->do_thread(wt);
3308
3309 #if INCLUDE_JFR
3310 Thread* sampler_thread = Jfr::sampler_thread();
3311 if (sampler_thread != NULL) {
3312 tc->do_thread(sampler_thread);
3313 }
3314
3315 #endif
3316
3317 // If CompilerThreads ever become non-JavaThreads, add them here
3318 }
3319
3320 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3321
3322 extern void JDK_Version_init();
3323
3324 // Preinitialize version info.
3325 VM_Version::early_initialize();
3326
3327 // Check version
3328 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3329
3330 // Initialize the output stream module
3331 ostream_init();
3332
3333 // Process java launcher properties.
3334 Arguments::process_sun_java_launcher_properties(args);
3335
3336 // Initialize the os module before using TLS
3337 os::init();
3338
3339 // Initialize system properties.
3340 Arguments::init_system_properties();
3341
3342 // So that JDK version can be used as a discrimintor when parsing arguments
3343 JDK_Version_init();
3344
3345 // Update/Initialize System properties after JDK version number is known
3346 Arguments::init_version_specific_system_properties();
3347
3348 // Parse arguments
3349 // Note: this internally calls os::init_container_support()
3350 jint parse_result = Arguments::parse(args);
3351 if (parse_result != JNI_OK) return parse_result;
3352
3353 os::init_before_ergo();
3354
3355 jint ergo_result = Arguments::apply_ergo();
3356 if (ergo_result != JNI_OK) return ergo_result;
3357
3358 if (PauseAtStartup) {
3359 os::pause();
3360 }
3361
3362 #ifndef USDT2
3363 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3364 #else /* USDT2 */
3365 HOTSPOT_VM_INIT_BEGIN();
3366 #endif /* USDT2 */
3367
3368 // Record VM creation timing statistics
3369 TraceVmCreationTime create_vm_timer;
3370 create_vm_timer.start();
3371
3372 // Timing (must come after argument parsing)
3373 TraceTime timer("Create VM", TraceStartupTime);
3374
3375 // Initialize the os module after parsing the args
3376 jint os_init_2_result = os::init_2();
3377 if (os_init_2_result != JNI_OK) return os_init_2_result;
3378
3379 jint adjust_after_os_result = Arguments::adjust_after_os();
3380 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3381
3382 // intialize TLS
3383 ThreadLocalStorage::init();
3384
3385 // Initialize output stream logging
3386 ostream_init_log();
3387
3388 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3389 // Must be before create_vm_init_agents()
3390 if (Arguments::init_libraries_at_startup()) {
3391 convert_vm_init_libraries_to_agents();
3392 }
3393
3394 // Launch -agentlib/-agentpath and converted -Xrun agents
3395 if (Arguments::init_agents_at_startup()) {
3396 create_vm_init_agents();
3397 }
3398
3399 // Initialize Threads state
3400 _thread_list = NULL;
3401 _number_of_threads = 0;
3402 _number_of_non_daemon_threads = 0;
3403
3404 // Initialize global data structures and create system classes in heap
3405 vm_init_globals();
3406
3407 // Attach the main thread to this os thread
3408 JavaThread* main_thread = new JavaThread();
3409 main_thread->set_thread_state(_thread_in_vm);
3410 // must do this before set_active_handles and initialize_thread_local_storage
3411 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3412 // change the stack size recorded here to one based on the java thread
3413 // stacksize. This adjusted size is what is used to figure the placement
3414 // of the guard pages.
3415 main_thread->record_stack_base_and_size();
3416 main_thread->initialize_thread_local_storage();
3417
3418 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3419
3420 if (!main_thread->set_as_starting_thread()) {
3421 vm_shutdown_during_initialization(
3422 "Failed necessary internal allocation. Out of swap space");
3423 delete main_thread;
3424 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3425 return JNI_ENOMEM;
3426 }
3427
3428 // Enable guard page *after* os::create_main_thread(), otherwise it would
3429 // crash Linux VM, see notes in os_linux.cpp.
3430 main_thread->create_stack_guard_pages();
3431
3432 // Initialize Java-Level synchronization subsystem
3433 ObjectMonitor::Initialize() ;
3434
3435 // Initialize global modules
3436 jint status = init_globals();
3437 if (status != JNI_OK) {
3438 delete main_thread;
3439 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3440 return status;
3441 }
3442
3443 JFR_ONLY(Jfr::on_vm_init();)
3444
3445 // Should be done after the heap is fully created
3446 main_thread->cache_global_variables();
3447
3448 HandleMark hm;
3449
3450 { MutexLocker mu(Threads_lock);
3451 Threads::add(main_thread);
3452 }
3453
3454 // Any JVMTI raw monitors entered in onload will transition into
3455 // real raw monitor. VM is setup enough here for raw monitor enter.
3456 JvmtiExport::transition_pending_onload_raw_monitors();
3457
3458 // Create the VMThread
3459 { TraceTime timer("Start VMThread", TraceStartupTime);
3460 VMThread::create();
3461 Thread* vmthread = VMThread::vm_thread();
3462
3463 if (!os::create_thread(vmthread, os::vm_thread))
3464 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3465
3466 // Wait for the VM thread to become ready, and VMThread::run to initialize
3467 // Monitors can have spurious returns, must always check another state flag
3468 {
3469 MutexLocker ml(Notify_lock);
3470 os::start_thread(vmthread);
3471 while (vmthread->active_handles() == NULL) {
3472 Notify_lock->wait();
3473 }
3474 }
3475 }
3476
3477 assert (Universe::is_fully_initialized(), "not initialized");
3478 if (VerifyDuringStartup) {
3479 // Make sure we're starting with a clean slate.
3480 VM_Verify verify_op;
3481 VMThread::execute(&verify_op);
3482 }
3483
3484 EXCEPTION_MARK;
3485
3486 // At this point, the Universe is initialized, but we have not executed
3487 // any byte code. Now is a good time (the only time) to dump out the
3488 // internal state of the JVM for sharing.
3489 if (DumpSharedSpaces) {
3490 MetaspaceShared::preload_and_dump(CHECK_0);
3491 ShouldNotReachHere();
3492 }
3493
3494 // Always call even when there are not JVMTI environments yet, since environments
3495 // may be attached late and JVMTI must track phases of VM execution
3496 JvmtiExport::enter_start_phase();
3497
3498 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3499 JvmtiExport::post_vm_start();
3500
3501 {
3502 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3503
3504 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3505 create_vm_init_libraries();
3506 }
3507
3508 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3509
3510 // Initialize java_lang.System (needed before creating the thread)
3511 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3512 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3513 Handle thread_group = create_initial_thread_group(CHECK_0);
3514 Universe::set_main_thread_group(thread_group());
3515 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3516 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3517 main_thread->set_threadObj(thread_object);
3518 // Set thread status to running since main thread has
3519 // been started and running.
3520 java_lang_Thread::set_thread_status(thread_object,
3521 java_lang_Thread::RUNNABLE);
3522
3523 // The VM creates & returns objects of this class. Make sure it's initialized.
3524 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3525
3526 // The VM preresolves methods to these classes. Make sure that they get initialized
3527 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3528 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3529 call_initializeSystemClass(CHECK_0);
3530
3531 // get the Java runtime name after java.lang.System is initialized
3532 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3533 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3534
3535 // an instance of OutOfMemory exception has been allocated earlier
3536 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3537 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3538 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3539 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3540 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3541 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3542 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3543 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3544 }
3545
3546 // See : bugid 4211085.
3547 // Background : the static initializer of java.lang.Compiler tries to read
3548 // property"java.compiler" and read & write property "java.vm.info".
3549 // When a security manager is installed through the command line
3550 // option "-Djava.security.manager", the above properties are not
3551 // readable and the static initializer for java.lang.Compiler fails
3552 // resulting in a NoClassDefFoundError. This can happen in any
3553 // user code which calls methods in java.lang.Compiler.
3554 // Hack : the hack is to pre-load and initialize this class, so that only
3555 // system domains are on the stack when the properties are read.
3556 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3557 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3558 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3559 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3560 // Once that is done, we should remove this hack.
3561 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3562
3563 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3564 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3565 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3566 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3567 // This should also be taken out as soon as 4211383 gets fixed.
3568 reset_vm_info_property(CHECK_0);
3569
3570 quicken_jni_functions();
3571
3572 // Set flag that basic initialization has completed. Used by exceptions and various
3573 // debug stuff, that does not work until all basic classes have been initialized.
3574 set_init_completed();
3575
3576 Metaspace::post_initialize();
3577
3578 #ifndef USDT2
3579 HS_DTRACE_PROBE(hotspot, vm__init__end);
3580 #else /* USDT2 */
3581 HOTSPOT_VM_INIT_END();
3582 #endif /* USDT2 */
3583
3584 // record VM initialization completion time
3585 #if INCLUDE_MANAGEMENT
3586 Management::record_vm_init_completed();
3587 #endif // INCLUDE_MANAGEMENT
3588
3589 // Compute system loader. Note that this has to occur after set_init_completed, since
3590 // valid exceptions may be thrown in the process.
3591 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3592 // set_init_completed has just been called, causing exceptions not to be shortcut
3593 // anymore. We call vm_exit_during_initialization directly instead.
3594 SystemDictionary::compute_java_system_loader(THREAD);
3595 if (HAS_PENDING_EXCEPTION) {
3596 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3597 }
3598
3599 #if INCLUDE_ALL_GCS
3600 // Support for ConcurrentMarkSweep. This should be cleaned up
3601 // and better encapsulated. The ugly nested if test would go away
3602 // once things are properly refactored. XXX YSR
3603 if (UseConcMarkSweepGC || UseG1GC) {
3604 if (UseConcMarkSweepGC) {
3605 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3606 } else {
3607 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3608 }
3609 if (HAS_PENDING_EXCEPTION) {
3610 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3611 }
3612 }
3613 #endif // INCLUDE_ALL_GCS
3614
3615 // Always call even when there are not JVMTI environments yet, since environments
3616 // may be attached late and JVMTI must track phases of VM execution
3617 JvmtiExport::enter_live_phase();
3618
3619 // Signal Dispatcher needs to be started before VMInit event is posted
3620 os::signal_init();
3621
3622 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3623 if (!DisableAttachMechanism) {
3624 AttachListener::vm_start();
3625 if (StartAttachListener || AttachListener::init_at_startup()) {
3626 AttachListener::init();
3627 }
3628 }
3629
3630 // Launch -Xrun agents
3631 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3632 // back-end can launch with -Xdebug -Xrunjdwp.
3633 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3634 create_vm_init_libraries();
3635 }
3636
3637 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3638 JvmtiExport::post_vm_initialized();
3639
3640 JFR_ONLY(Jfr::on_vm_start();)
3641
3642 if (CleanChunkPoolAsync) {
3643 Chunk::start_chunk_pool_cleaner_task();
3644 }
3645
3646 // initialize compiler(s)
3647 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3648 CompileBroker::compilation_init();
3649 #endif
3650
3651 if (EnableInvokeDynamic) {
3652 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3653 // It is done after compilers are initialized, because otherwise compilations of
3654 // signature polymorphic MH intrinsics can be missed
3655 // (see SystemDictionary::find_method_handle_intrinsic).
3656 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3657 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3658 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3659 }
3660
3661 #if INCLUDE_MANAGEMENT
3662 Management::initialize(THREAD);
3663 #endif // INCLUDE_MANAGEMENT
3664
3665 if (HAS_PENDING_EXCEPTION) {
3666 // management agent fails to start possibly due to
3667 // configuration problem and is responsible for printing
3668 // stack trace if appropriate. Simply exit VM.
3669 vm_exit(1);
3670 }
3671
3672 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3673 if (MemProfiling) MemProfiler::engage();
3674 StatSampler::engage();
3675 if (CheckJNICalls) JniPeriodicChecker::engage();
3676
3677 BiasedLocking::init();
3678
3679 #if INCLUDE_RTM_OPT
3680 RTMLockingCounters::init();
3681 #endif
3682
3683 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3684 call_postVMInitHook(THREAD);
3685 // The Java side of PostVMInitHook.run must deal with all
3686 // exceptions and provide means of diagnosis.
3687 if (HAS_PENDING_EXCEPTION) {
3688 CLEAR_PENDING_EXCEPTION;
3689 }
3690 }
3691
3692 {
3693 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3694 // Make sure the watcher thread can be started by WatcherThread::start()
3695 // or by dynamic enrollment.
3696 WatcherThread::make_startable();
3697 // Start up the WatcherThread if there are any periodic tasks
3698 // NOTE: All PeriodicTasks should be registered by now. If they
3699 // aren't, late joiners might appear to start slowly (we might
3700 // take a while to process their first tick).
3701 if (PeriodicTask::num_tasks() > 0) {
3702 WatcherThread::start();
3703 }
3704 }
3705
3706 create_vm_timer.end();
3707 #ifdef ASSERT
3708 _vm_complete = true;
3709 #endif
3710 return JNI_OK;
3711 }
3712
3713 // type for the Agent_OnLoad and JVM_OnLoad entry points
3714 extern "C" {
3715 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3716 }
3717 // Find a command line agent library and return its entry point for
3718 // -agentlib: -agentpath: -Xrun
3719 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3720 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3721 OnLoadEntry_t on_load_entry = NULL;
3722 void *library = NULL;
3723
3724 if (!agent->valid()) {
3725 char buffer[JVM_MAXPATHLEN];
3726 char ebuf[1024];
3727 const char *name = agent->name();
3728 const char *msg = "Could not find agent library ";
3729
3730 // First check to see if agent is statically linked into executable
3731 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3732 library = agent->os_lib();
3733 } else if (agent->is_absolute_path()) {
3734 library = os::dll_load(name, ebuf, sizeof ebuf);
3735 if (library == NULL) {
3736 const char *sub_msg = " in absolute path, with error: ";
3737 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3738 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3739 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3740 // If we can't find the agent, exit.
3741 vm_exit_during_initialization(buf, NULL);
3742 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3743 }
3744 } else {
3745 // Try to load the agent from the standard dll directory
3746 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3747 name)) {
3748 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3749 }
3750 if (library == NULL) { // Try the local directory
3751 char ns[1] = {0};
3752 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3753 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3754 }
3755 if (library == NULL) {
3756 const char *sub_msg = " on the library path, with error: ";
3757 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3758 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3759 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3760 // If we can't find the agent, exit.
3761 vm_exit_during_initialization(buf, NULL);
3762 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3763 }
3764 }
3765 }
3766 agent->set_os_lib(library);
3767 agent->set_valid();
3768 }
3769
3770 // Find the OnLoad function.
3771 on_load_entry =
3772 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3773 false,
3774 on_load_symbols,
3775 num_symbol_entries));
3776 return on_load_entry;
3777 }
3778
3779 // Find the JVM_OnLoad entry point
3780 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3781 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3782 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3783 }
3784
3785 // Find the Agent_OnLoad entry point
3786 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3787 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3788 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3789 }
3790
3791 // For backwards compatibility with -Xrun
3792 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3793 // treated like -agentpath:
3794 // Must be called before agent libraries are created
3795 void Threads::convert_vm_init_libraries_to_agents() {
3796 AgentLibrary* agent;
3797 AgentLibrary* next;
3798
3799 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3800 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3801 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3802
3803 // If there is an JVM_OnLoad function it will get called later,
3804 // otherwise see if there is an Agent_OnLoad
3805 if (on_load_entry == NULL) {
3806 on_load_entry = lookup_agent_on_load(agent);
3807 if (on_load_entry != NULL) {
3808 // switch it to the agent list -- so that Agent_OnLoad will be called,
3809 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3810 Arguments::convert_library_to_agent(agent);
3811 } else {
3812 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3813 }
3814 }
3815 }
3816 }
3817
3818 // Create agents for -agentlib: -agentpath: and converted -Xrun
3819 // Invokes Agent_OnLoad
3820 // Called very early -- before JavaThreads exist
3821 void Threads::create_vm_init_agents() {
3822 extern struct JavaVM_ main_vm;
3823 AgentLibrary* agent;
3824
3825 JvmtiExport::enter_onload_phase();
3826
3827 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3828 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3829
3830 if (on_load_entry != NULL) {
3831 // Invoke the Agent_OnLoad function
3832 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3833 if (err != JNI_OK) {
3834 vm_exit_during_initialization("agent library failed to init", agent->name());
3835 }
3836 } else {
3837 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3838 }
3839 }
3840 JvmtiExport::enter_primordial_phase();
3841 }
3842
3843 extern "C" {
3844 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3845 }
3846
3847 void Threads::shutdown_vm_agents() {
3848 // Send any Agent_OnUnload notifications
3849 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3850 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3851 extern struct JavaVM_ main_vm;
3852 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3853
3854 // Find the Agent_OnUnload function.
3855 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3856 os::find_agent_function(agent,
3857 false,
3858 on_unload_symbols,
3859 num_symbol_entries));
3860
3861 // Invoke the Agent_OnUnload function
3862 if (unload_entry != NULL) {
3863 JavaThread* thread = JavaThread::current();
3864 ThreadToNativeFromVM ttn(thread);
3865 HandleMark hm(thread);
3866 (*unload_entry)(&main_vm);
3867 }
3868 }
3869 }
3870
3871 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3872 // Invokes JVM_OnLoad
3873 void Threads::create_vm_init_libraries() {
3874 extern struct JavaVM_ main_vm;
3875 AgentLibrary* agent;
3876
3877 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3878 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3879
3880 if (on_load_entry != NULL) {
3881 // Invoke the JVM_OnLoad function
3882 JavaThread* thread = JavaThread::current();
3883 ThreadToNativeFromVM ttn(thread);
3884 HandleMark hm(thread);
3885 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3886 if (err != JNI_OK) {
3887 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3888 }
3889 } else {
3890 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3891 }
3892 }
3893 }
3894
3895 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3896 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3897
3898 JavaThread* java_thread = NULL;
3899 // Sequential search for now. Need to do better optimization later.
3900 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3901 oop tobj = thread->threadObj();
3902 if (!thread->is_exiting() &&
3903 tobj != NULL &&
3904 java_tid == java_lang_Thread::thread_id(tobj)) {
3905 java_thread = thread;
3906 break;
3907 }
3908 }
3909 return java_thread;
3910 }
3911
3912
3913 // Last thread running calls java.lang.Shutdown.shutdown()
3914 void JavaThread::invoke_shutdown_hooks() {
3915 HandleMark hm(this);
3916
3917 // We could get here with a pending exception, if so clear it now.
3918 if (this->has_pending_exception()) {
3919 this->clear_pending_exception();
3920 }
3921
3922 EXCEPTION_MARK;
3923 Klass* k =
3924 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3925 THREAD);
3926 if (k != NULL) {
3927 // SystemDictionary::resolve_or_null will return null if there was
3928 // an exception. If we cannot load the Shutdown class, just don't
3929 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3930 // and finalizers (if runFinalizersOnExit is set) won't be run.
3931 // Note that if a shutdown hook was registered or runFinalizersOnExit
3932 // was called, the Shutdown class would have already been loaded
3933 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3934 instanceKlassHandle shutdown_klass (THREAD, k);
3935 JavaValue result(T_VOID);
3936 JavaCalls::call_static(&result,
3937 shutdown_klass,
3938 vmSymbols::shutdown_method_name(),
3939 vmSymbols::void_method_signature(),
3940 THREAD);
3941 }
3942 CLEAR_PENDING_EXCEPTION;
3943 }
3944
3945 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3946 // the program falls off the end of main(). Another VM exit path is through
3947 // vm_exit() when the program calls System.exit() to return a value or when
3948 // there is a serious error in VM. The two shutdown paths are not exactly
3949 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3950 // and VM_Exit op at VM level.
3951 //
3952 // Shutdown sequence:
3953 // + Shutdown native memory tracking if it is on
3954 // + Wait until we are the last non-daemon thread to execute
3955 // <-- every thing is still working at this moment -->
3956 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3957 // shutdown hooks, run finalizers if finalization-on-exit
3958 // + Call before_exit(), prepare for VM exit
3959 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3960 // currently the only user of this mechanism is File.deleteOnExit())
3961 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3962 // post thread end and vm death events to JVMTI,
3963 // stop signal thread
3964 // + Call JavaThread::exit(), it will:
3965 // > release JNI handle blocks, remove stack guard pages
3966 // > remove this thread from Threads list
3967 // <-- no more Java code from this thread after this point -->
3968 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3969 // the compiler threads at safepoint
3970 // <-- do not use anything that could get blocked by Safepoint -->
3971 // + Disable tracing at JNI/JVM barriers
3972 // + Set _vm_exited flag for threads that are still running native code
3973 // + Delete this thread
3974 // + Call exit_globals()
3975 // > deletes tty
3976 // > deletes PerfMemory resources
3977 // + Return to caller
3978
3979 bool Threads::destroy_vm() {
3980 JavaThread* thread = JavaThread::current();
3981
3982 #ifdef ASSERT
3983 _vm_complete = false;
3984 #endif
3985 // Wait until we are the last non-daemon thread to execute
3986 { MutexLocker nu(Threads_lock);
3987 while (Threads::number_of_non_daemon_threads() > 1 )
3988 // This wait should make safepoint checks, wait without a timeout,
3989 // and wait as a suspend-equivalent condition.
3990 //
3991 // Note: If the FlatProfiler is running and this thread is waiting
3992 // for another non-daemon thread to finish, then the FlatProfiler
3993 // is waiting for the external suspend request on this thread to
3994 // complete. wait_for_ext_suspend_completion() will eventually
3995 // timeout, but that takes time. Making this wait a suspend-
3996 // equivalent condition solves that timeout problem.
3997 //
3998 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3999 Mutex::_as_suspend_equivalent_flag);
4000 }
4001
4002 EventShutdown e;
4003 if (e.should_commit()) {
4004 e.set_reason("No remaining non-daemon Java threads");
4005 e.commit();
4006 }
4007
4008 // Hang forever on exit if we are reporting an error.
4009 if (ShowMessageBoxOnError && is_error_reported()) {
4010 os::infinite_sleep();
4011 }
4012 os::wait_for_keypress_at_exit();
4013
4014 if (JDK_Version::is_jdk12x_version()) {
4015 // We are the last thread running, so check if finalizers should be run.
4016 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4017 HandleMark rm(thread);
4018 Universe::run_finalizers_on_exit();
4019 } else {
4020 // run Java level shutdown hooks
4021 thread->invoke_shutdown_hooks();
4022 }
4023
4024 before_exit(thread);
4025
4026 thread->exit(true);
4027
4028 // Stop VM thread.
4029 {
4030 // 4945125 The vm thread comes to a safepoint during exit.
4031 // GC vm_operations can get caught at the safepoint, and the
4032 // heap is unparseable if they are caught. Grab the Heap_lock
4033 // to prevent this. The GC vm_operations will not be able to
4034 // queue until after the vm thread is dead. After this point,
4035 // we'll never emerge out of the safepoint before the VM exits.
4036
4037 MutexLocker ml(Heap_lock);
4038
4039 VMThread::wait_for_vm_thread_exit();
4040 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4041 VMThread::destroy();
4042 }
4043
4044 // clean up ideal graph printers
4045 #if defined(COMPILER2) && !defined(PRODUCT)
4046 IdealGraphPrinter::clean_up();
4047 #endif
4048
4049 // Now, all Java threads are gone except daemon threads. Daemon threads
4050 // running Java code or in VM are stopped by the Safepoint. However,
4051 // daemon threads executing native code are still running. But they
4052 // will be stopped at native=>Java/VM barriers. Note that we can't
4053 // simply kill or suspend them, as it is inherently deadlock-prone.
4054
4055 #ifndef PRODUCT
4056 // disable function tracing at JNI/JVM barriers
4057 TraceJNICalls = false;
4058 TraceJVMCalls = false;
4059 TraceRuntimeCalls = false;
4060 #endif
4061
4062 VM_Exit::set_vm_exited();
4063
4064 notify_vm_shutdown();
4065
4066 delete thread;
4067
4068 // exit_globals() will delete tty
4069 exit_globals();
4070
4071 return true;
4072 }
4073
4074
4075 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4076 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4077 return is_supported_jni_version(version);
4078 }
4079
4080
4081 jboolean Threads::is_supported_jni_version(jint version) {
4082 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4083 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4084 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4085 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4086 return JNI_FALSE;
4087 }
4088
4089
4090 void Threads::add(JavaThread* p, bool force_daemon) {
4091 // The threads lock must be owned at this point
4092 assert_locked_or_safepoint(Threads_lock);
4093
4094 // See the comment for this method in thread.hpp for its purpose and
4095 // why it is called here.
4096 p->initialize_queues();
4097 p->set_next(_thread_list);
4098 _thread_list = p;
4099 _number_of_threads++;
4100 oop threadObj = p->threadObj();
4101 bool daemon = true;
4102 // Bootstrapping problem: threadObj can be null for initial
4103 // JavaThread (or for threads attached via JNI)
4104 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4105 _number_of_non_daemon_threads++;
4106 daemon = false;
4107 }
4108
4109 ThreadService::add_thread(p, daemon);
4110
4111 // Possible GC point.
4112 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4113 }
4114
4115 void Threads::remove(JavaThread* p) {
4116 // Extra scope needed for Thread_lock, so we can check
4117 // that we do not remove thread without safepoint code notice
4118 { MutexLocker ml(Threads_lock);
4119
4120 assert(includes(p), "p must be present");
4121
4122 JavaThread* current = _thread_list;
4123 JavaThread* prev = NULL;
4124
4125 while (current != p) {
4126 prev = current;
4127 current = current->next();
4128 }
4129
4130 if (prev) {
4131 prev->set_next(current->next());
4132 } else {
4133 _thread_list = p->next();
4134 }
4135 _number_of_threads--;
4136 oop threadObj = p->threadObj();
4137 bool daemon = true;
4138 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4139 _number_of_non_daemon_threads--;
4140 daemon = false;
4141
4142 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4143 // on destroy_vm will wake up.
4144 if (number_of_non_daemon_threads() == 1)
4145 Threads_lock->notify_all();
4146 }
4147 ThreadService::remove_thread(p, daemon);
4148
4149 // Make sure that safepoint code disregard this thread. This is needed since
4150 // the thread might mess around with locks after this point. This can cause it
4151 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4152 // of this thread since it is removed from the queue.
4153 p->set_terminated_value();
4154 } // unlock Threads_lock
4155
4156 // Since Events::log uses a lock, we grab it outside the Threads_lock
4157 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4158 }
4159
4160 // Threads_lock must be held when this is called (or must be called during a safepoint)
4161 bool Threads::includes(JavaThread* p) {
4162 assert(Threads_lock->is_locked(), "sanity check");
4163 ALL_JAVA_THREADS(q) {
4164 if (q == p ) {
4165 return true;
4166 }
4167 }
4168 return false;
4169 }
4170
4171 // Operations on the Threads list for GC. These are not explicitly locked,
4172 // but the garbage collector must provide a safe context for them to run.
4173 // In particular, these things should never be called when the Threads_lock
4174 // is held by some other thread. (Note: the Safepoint abstraction also
4175 // uses the Threads_lock to gurantee this property. It also makes sure that
4176 // all threads gets blocked when exiting or starting).
4177
4178 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4179 ALL_JAVA_THREADS(p) {
4180 p->oops_do(f, cld_f, cf);
4181 }
4182 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4183 }
4184
4185 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4186 // Introduce a mechanism allowing parallel threads to claim threads as
4187 // root groups. Overhead should be small enough to use all the time,
4188 // even in sequential code.
4189 SharedHeap* sh = SharedHeap::heap();
4190 // Cannot yet substitute active_workers for n_par_threads
4191 // because of G1CollectedHeap::verify() use of
4192 // SharedHeap::process_roots(). n_par_threads == 0 will
4193 // turn off parallelism in process_roots while active_workers
4194 // is being used for parallelism elsewhere.
4195 bool is_par = sh->n_par_threads() > 0;
4196 assert(!is_par ||
4197 (SharedHeap::heap()->n_par_threads() ==
4198 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4199 int cp = SharedHeap::heap()->strong_roots_parity();
4200 ALL_JAVA_THREADS(p) {
4201 if (p->claim_oops_do(is_par, cp)) {
4202 p->oops_do(f, cld_f, cf);
4203 }
4204 }
4205 VMThread* vmt = VMThread::vm_thread();
4206 if (vmt->claim_oops_do(is_par, cp)) {
4207 vmt->oops_do(f, cld_f, cf);
4208 }
4209 }
4210
4211 #if INCLUDE_ALL_GCS
4212 // Used by ParallelScavenge
4213 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4214 ALL_JAVA_THREADS(p) {
4215 q->enqueue(new ThreadRootsTask(p));
4216 }
4217 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4218 }
4219
4220 // Used by Parallel Old
4221 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4222 ALL_JAVA_THREADS(p) {
4223 q->enqueue(new ThreadRootsMarkingTask(p));
4224 }
4225 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4226 }
4227 #endif // INCLUDE_ALL_GCS
4228
4229 void Threads::nmethods_do(CodeBlobClosure* cf) {
4230 ALL_JAVA_THREADS(p) {
4231 p->nmethods_do(cf);
4232 }
4233 VMThread::vm_thread()->nmethods_do(cf);
4234 }
4235
4236 void Threads::metadata_do(void f(Metadata*)) {
4237 ALL_JAVA_THREADS(p) {
4238 p->metadata_do(f);
4239 }
4240 }
4241
4242 void Threads::gc_epilogue() {
4243 ALL_JAVA_THREADS(p) {
4244 p->gc_epilogue();
4245 }
4246 }
4247
4248 void Threads::gc_prologue() {
4249 ALL_JAVA_THREADS(p) {
4250 p->gc_prologue();
4251 }
4252 }
4253
4254 void Threads::deoptimized_wrt_marked_nmethods() {
4255 ALL_JAVA_THREADS(p) {
4256 p->deoptimized_wrt_marked_nmethods();
4257 }
4258 }
4259
4260
4261 // Get count Java threads that are waiting to enter the specified monitor.
4262 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4263 address monitor, bool doLock) {
4264 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4265 "must grab Threads_lock or be at safepoint");
4266 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4267
4268 int i = 0;
4269 {
4270 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4271 ALL_JAVA_THREADS(p) {
4272 if (p->is_Compiler_thread()) continue;
4273
4274 address pending = (address)p->current_pending_monitor();
4275 if (pending == monitor) { // found a match
4276 if (i < count) result->append(p); // save the first count matches
4277 i++;
4278 }
4279 }
4280 }
4281 return result;
4282 }
4283
4284
4285 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4286 assert(doLock ||
4287 Threads_lock->owned_by_self() ||
4288 SafepointSynchronize::is_at_safepoint(),
4289 "must grab Threads_lock or be at safepoint");
4290
4291 // NULL owner means not locked so we can skip the search
4292 if (owner == NULL) return NULL;
4293
4294 {
4295 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4296 ALL_JAVA_THREADS(p) {
4297 // first, see if owner is the address of a Java thread
4298 if (owner == (address)p) return p;
4299 }
4300 }
4301 // Cannot assert on lack of success here since this function may be
4302 // used by code that is trying to report useful problem information
4303 // like deadlock detection.
4304 if (UseHeavyMonitors) return NULL;
4305
4306 //
4307 // If we didn't find a matching Java thread and we didn't force use of
4308 // heavyweight monitors, then the owner is the stack address of the
4309 // Lock Word in the owning Java thread's stack.
4310 //
4311 JavaThread* the_owner = NULL;
4312 {
4313 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4314 ALL_JAVA_THREADS(q) {
4315 if (q->is_lock_owned(owner)) {
4316 the_owner = q;
4317 break;
4318 }
4319 }
4320 }
4321 // cannot assert on lack of success here; see above comment
4322 return the_owner;
4323 }
4324
4325 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4326 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4327 char buf[32];
4328 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4329
4330 st->print_cr("Full thread dump %s (%s %s):",
4331 Abstract_VM_Version::vm_name(),
4332 Abstract_VM_Version::vm_release(),
4333 Abstract_VM_Version::vm_info_string()
4334 );
4335 st->cr();
4336
4337 #if INCLUDE_ALL_GCS
4338 // Dump concurrent locks
4339 ConcurrentLocksDump concurrent_locks;
4340 if (print_concurrent_locks) {
4341 concurrent_locks.dump_at_safepoint();
4342 }
4343 #endif // INCLUDE_ALL_GCS
4344
4345 ALL_JAVA_THREADS(p) {
4346 ResourceMark rm;
4347 p->print_on(st);
4348 if (print_stacks) {
4349 if (internal_format) {
4350 p->trace_stack();
4351 } else {
4352 p->print_stack_on(st);
4353 }
4354 }
4355 st->cr();
4356 #if INCLUDE_ALL_GCS
4357 if (print_concurrent_locks) {
4358 concurrent_locks.print_locks_on(p, st);
4359 }
4360 #endif // INCLUDE_ALL_GCS
4361 }
4362
4363 VMThread::vm_thread()->print_on(st);
4364 st->cr();
4365 Universe::heap()->print_gc_threads_on(st);
4366 WatcherThread* wt = WatcherThread::watcher_thread();
4367 if (wt != NULL) {
4368 wt->print_on(st);
4369 st->cr();
4370 }
4371 CompileBroker::print_compiler_threads_on(st);
4372 st->flush();
4373 }
4374
4375 // Threads::print_on_error() is called by fatal error handler. It's possible
4376 // that VM is not at safepoint and/or current thread is inside signal handler.
4377 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4378 // memory (even in resource area), it might deadlock the error handler.
4379 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4380 bool found_current = false;
4381 st->print_cr("Java Threads: ( => current thread )");
4382 ALL_JAVA_THREADS(thread) {
4383 bool is_current = (current == thread);
4384 found_current = found_current || is_current;
4385
4386 st->print("%s", is_current ? "=>" : " ");
4387
4388 st->print(PTR_FORMAT, thread);
4389 st->print(" ");
4390 thread->print_on_error(st, buf, buflen);
4391 st->cr();
4392 }
4393 st->cr();
4394
4395 st->print_cr("Other Threads:");
4396 if (VMThread::vm_thread()) {
4397 bool is_current = (current == VMThread::vm_thread());
4398 found_current = found_current || is_current;
4399 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4400
4401 st->print(PTR_FORMAT, VMThread::vm_thread());
4402 st->print(" ");
4403 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4404 st->cr();
4405 }
4406 WatcherThread* wt = WatcherThread::watcher_thread();
4407 if (wt != NULL) {
4408 bool is_current = (current == wt);
4409 found_current = found_current || is_current;
4410 st->print("%s", is_current ? "=>" : " ");
4411
4412 st->print(PTR_FORMAT, wt);
4413 st->print(" ");
4414 wt->print_on_error(st, buf, buflen);
4415 st->cr();
4416 }
4417 if (!found_current) {
4418 st->cr();
4419 st->print("=>" PTR_FORMAT " (exited) ", current);
4420 current->print_on_error(st, buf, buflen);
4421 st->cr();
4422 }
4423 }
4424
4425 // Internal SpinLock and Mutex
4426 // Based on ParkEvent
4427
4428 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4429 //
4430 // We employ SpinLocks _only for low-contention, fixed-length
4431 // short-duration critical sections where we're concerned
4432 // about native mutex_t or HotSpot Mutex:: latency.
4433 // The mux construct provides a spin-then-block mutual exclusion
4434 // mechanism.
4435 //
4436 // Testing has shown that contention on the ListLock guarding gFreeList
4437 // is common. If we implement ListLock as a simple SpinLock it's common
4438 // for the JVM to devolve to yielding with little progress. This is true
4439 // despite the fact that the critical sections protected by ListLock are
4440 // extremely short.
4441 //
4442 // TODO-FIXME: ListLock should be of type SpinLock.
4443 // We should make this a 1st-class type, integrated into the lock
4444 // hierarchy as leaf-locks. Critically, the SpinLock structure
4445 // should have sufficient padding to avoid false-sharing and excessive
4446 // cache-coherency traffic.
4447
4448
4449 typedef volatile int SpinLockT ;
4450
4451 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4452 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4453 return ; // normal fast-path return
4454 }
4455
4456 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4457 TEVENT (SpinAcquire - ctx) ;
4458 int ctr = 0 ;
4459 int Yields = 0 ;
4460 for (;;) {
4461 while (*adr != 0) {
4462 ++ctr ;
4463 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4464 if (Yields > 5) {
4465 os::naked_short_sleep(1);
4466 } else {
4467 os::NakedYield() ;
4468 ++Yields ;
4469 }
4470 } else {
4471 SpinPause() ;
4472 }
4473 }
4474 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4475 }
4476 }
4477
4478 void Thread::SpinRelease (volatile int * adr) {
4479 assert (*adr != 0, "invariant") ;
4480 OrderAccess::fence() ; // guarantee at least release consistency.
4481 // Roach-motel semantics.
4482 // It's safe if subsequent LDs and STs float "up" into the critical section,
4483 // but prior LDs and STs within the critical section can't be allowed
4484 // to reorder or float past the ST that releases the lock.
4485 *adr = 0 ;
4486 }
4487
4488 // muxAcquire and muxRelease:
4489 //
4490 // * muxAcquire and muxRelease support a single-word lock-word construct.
4491 // The LSB of the word is set IFF the lock is held.
4492 // The remainder of the word points to the head of a singly-linked list
4493 // of threads blocked on the lock.
4494 //
4495 // * The current implementation of muxAcquire-muxRelease uses its own
4496 // dedicated Thread._MuxEvent instance. If we're interested in
4497 // minimizing the peak number of extant ParkEvent instances then
4498 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4499 // as certain invariants were satisfied. Specifically, care would need
4500 // to be taken with regards to consuming unpark() "permits".
4501 // A safe rule of thumb is that a thread would never call muxAcquire()
4502 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4503 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4504 // consume an unpark() permit intended for monitorenter, for instance.
4505 // One way around this would be to widen the restricted-range semaphore
4506 // implemented in park(). Another alternative would be to provide
4507 // multiple instances of the PlatformEvent() for each thread. One
4508 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4509 //
4510 // * Usage:
4511 // -- Only as leaf locks
4512 // -- for short-term locking only as muxAcquire does not perform
4513 // thread state transitions.
4514 //
4515 // Alternatives:
4516 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4517 // but with parking or spin-then-park instead of pure spinning.
4518 // * Use Taura-Oyama-Yonenzawa locks.
4519 // * It's possible to construct a 1-0 lock if we encode the lockword as
4520 // (List,LockByte). Acquire will CAS the full lockword while Release
4521 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4522 // acquiring threads use timers (ParkTimed) to detect and recover from
4523 // the stranding window. Thread/Node structures must be aligned on 256-byte
4524 // boundaries by using placement-new.
4525 // * Augment MCS with advisory back-link fields maintained with CAS().
4526 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4527 // The validity of the backlinks must be ratified before we trust the value.
4528 // If the backlinks are invalid the exiting thread must back-track through the
4529 // the forward links, which are always trustworthy.
4530 // * Add a successor indication. The LockWord is currently encoded as
4531 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4532 // to provide the usual futile-wakeup optimization.
4533 // See RTStt for details.
4534 // * Consider schedctl.sc_nopreempt to cover the critical section.
4535 //
4536
4537
4538 typedef volatile intptr_t MutexT ; // Mux Lock-word
4539 enum MuxBits { LOCKBIT = 1 } ;
4540
4541 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4542 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4543 if (w == 0) return ;
4544 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4545 return ;
4546 }
4547
4548 TEVENT (muxAcquire - Contention) ;
4549 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4550 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4551 for (;;) {
4552 int its = (os::is_MP() ? 100 : 0) + 1 ;
4553
4554 // Optional spin phase: spin-then-park strategy
4555 while (--its >= 0) {
4556 w = *Lock ;
4557 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4558 return ;
4559 }
4560 }
4561
4562 Self->reset() ;
4563 Self->OnList = intptr_t(Lock) ;
4564 // The following fence() isn't _strictly necessary as the subsequent
4565 // CAS() both serializes execution and ratifies the fetched *Lock value.
4566 OrderAccess::fence();
4567 for (;;) {
4568 w = *Lock ;
4569 if ((w & LOCKBIT) == 0) {
4570 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4571 Self->OnList = 0 ; // hygiene - allows stronger asserts
4572 return ;
4573 }
4574 continue ; // Interference -- *Lock changed -- Just retry
4575 }
4576 assert (w & LOCKBIT, "invariant") ;
4577 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4578 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4579 }
4580
4581 while (Self->OnList != 0) {
4582 Self->park() ;
4583 }
4584 }
4585 }
4586
4587 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4588 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4589 if (w == 0) return ;
4590 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4591 return ;
4592 }
4593
4594 TEVENT (muxAcquire - Contention) ;
4595 ParkEvent * ReleaseAfter = NULL ;
4596 if (ev == NULL) {
4597 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4598 }
4599 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4600 for (;;) {
4601 guarantee (ev->OnList == 0, "invariant") ;
4602 int its = (os::is_MP() ? 100 : 0) + 1 ;
4603
4604 // Optional spin phase: spin-then-park strategy
4605 while (--its >= 0) {
4606 w = *Lock ;
4607 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4608 if (ReleaseAfter != NULL) {
4609 ParkEvent::Release (ReleaseAfter) ;
4610 }
4611 return ;
4612 }
4613 }
4614
4615 ev->reset() ;
4616 ev->OnList = intptr_t(Lock) ;
4617 // The following fence() isn't _strictly necessary as the subsequent
4618 // CAS() both serializes execution and ratifies the fetched *Lock value.
4619 OrderAccess::fence();
4620 for (;;) {
4621 w = *Lock ;
4622 if ((w & LOCKBIT) == 0) {
4623 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4624 ev->OnList = 0 ;
4625 // We call ::Release while holding the outer lock, thus
4626 // artificially lengthening the critical section.
4627 // Consider deferring the ::Release() until the subsequent unlock(),
4628 // after we've dropped the outer lock.
4629 if (ReleaseAfter != NULL) {
4630 ParkEvent::Release (ReleaseAfter) ;
4631 }
4632 return ;
4633 }
4634 continue ; // Interference -- *Lock changed -- Just retry
4635 }
4636 assert (w & LOCKBIT, "invariant") ;
4637 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4638 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4639 }
4640
4641 while (ev->OnList != 0) {
4642 ev->park() ;
4643 }
4644 }
4645 }
4646
4647 // Release() must extract a successor from the list and then wake that thread.
4648 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4649 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4650 // Release() would :
4651 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4652 // (B) Extract a successor from the private list "in-hand"
4653 // (C) attempt to CAS() the residual back into *Lock over null.
4654 // If there were any newly arrived threads and the CAS() would fail.
4655 // In that case Release() would detach the RATs, re-merge the list in-hand
4656 // with the RATs and repeat as needed. Alternately, Release() might
4657 // detach and extract a successor, but then pass the residual list to the wakee.
4658 // The wakee would be responsible for reattaching and remerging before it
4659 // competed for the lock.
4660 //
4661 // Both "pop" and DMR are immune from ABA corruption -- there can be
4662 // multiple concurrent pushers, but only one popper or detacher.
4663 // This implementation pops from the head of the list. This is unfair,
4664 // but tends to provide excellent throughput as hot threads remain hot.
4665 // (We wake recently run threads first).
4666
4667 void Thread::muxRelease (volatile intptr_t * Lock) {
4668 for (;;) {
4669 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4670 assert (w & LOCKBIT, "invariant") ;
4671 if (w == LOCKBIT) return ;
4672 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4673 assert (List != NULL, "invariant") ;
4674 assert (List->OnList == intptr_t(Lock), "invariant") ;
4675 ParkEvent * nxt = List->ListNext ;
4676
4677 // The following CAS() releases the lock and pops the head element.
4678 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4679 continue ;
4680 }
4681 List->OnList = 0 ;
4682 OrderAccess::fence() ;
4683 List->unpark () ;
4684 return ;
4685 }
4686 }
4687
4688
4689 void Threads::verify() {
4690 ALL_JAVA_THREADS(p) {
4691 p->verify();
4692 }
4693 VMThread* thread = VMThread::vm_thread();
4694 if (thread != NULL) thread->verify();
4695 }