1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jvmtifiles/jvmtiEnv.hpp"
36 #include "memory/gcLocker.inline.hpp"
37 #include "memory/metaspaceShared.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "memory/universe.inline.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/objArrayOop.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/symbol.hpp"
44 #include "prims/jvm_misc.hpp"
45 #include "prims/jvmtiExport.hpp"
46 #include "prims/jvmtiThreadState.hpp"
47 #include "prims/privilegedStack.hpp"
48 #include "runtime/arguments.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/deoptimization.hpp"
51 #include "runtime/fprofiler.hpp"
52 #include "runtime/frame.inline.hpp"
53 #include "runtime/init.hpp"
54 #include "runtime/interfaceSupport.hpp"
55 #include "runtime/java.hpp"
56 #include "runtime/javaCalls.hpp"
57 #include "runtime/jniPeriodicChecker.hpp"
58 #include "runtime/memprofiler.hpp"
59 #include "runtime/mutexLocker.hpp"
60 #include "runtime/objectMonitor.hpp"
61 #include "runtime/orderAccess.inline.hpp"
62 #include "runtime/osThread.hpp"
63 #include "runtime/safepoint.hpp"
64 #include "runtime/sharedRuntime.hpp"
65 #include "runtime/statSampler.hpp"
66 #include "runtime/stubRoutines.hpp"
67 #include "runtime/task.hpp"
68 #include "runtime/thread.inline.hpp"
69 #include "runtime/threadCritical.hpp"
70 #include "runtime/threadLocalStorage.hpp"
71 #include "runtime/vframe.hpp"
72 #include "runtime/vframeArray.hpp"
73 #include "runtime/vframe_hp.hpp"
74 #include "runtime/vmThread.hpp"
75 #include "runtime/vm_operations.hpp"
76 #include "services/attachListener.hpp"
77 #include "services/management.hpp"
78 #include "services/memTracker.hpp"
79 #include "services/threadService.hpp"
80 #include "trace/tracing.hpp"
81 #include "trace/traceMacros.hpp"
82 #include "utilities/defaultStream.hpp"
83 #include "utilities/dtrace.hpp"
84 #include "utilities/events.hpp"
85 #include "utilities/preserveException.hpp"
86 #include "utilities/macros.hpp"
87 #ifdef TARGET_OS_FAMILY_linux
88 # include "os_linux.inline.hpp"
89 #endif
90 #ifdef TARGET_OS_FAMILY_solaris
91 # include "os_solaris.inline.hpp"
92 #endif
93 #ifdef TARGET_OS_FAMILY_windows
94 # include "os_windows.inline.hpp"
95 #endif
96 #ifdef TARGET_OS_FAMILY_bsd
97 # include "os_bsd.inline.hpp"
98 #endif
99 #if INCLUDE_ALL_GCS
100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
102 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
103 #endif // INCLUDE_ALL_GCS
104 #ifdef COMPILER1
105 #include "c1/c1_Compiler.hpp"
106 #endif
107 #ifdef COMPILER2
108 #include "opto/c2compiler.hpp"
109 #include "opto/idealGraphPrinter.hpp"
110 #endif
111 #if INCLUDE_RTM_OPT
112 #include "runtime/rtmLocking.hpp"
113 #endif
114
115 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
116
117 #ifdef DTRACE_ENABLED
118
119 // Only bother with this argument setup if dtrace is available
120
121 #ifndef USDT2
122 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
123 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
124 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
125 intptr_t, intptr_t, bool);
126 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
127 intptr_t, intptr_t, bool);
128
129 #define DTRACE_THREAD_PROBE(probe, javathread) \
130 { \
131 ResourceMark rm(this); \
132 int len = 0; \
133 const char* name = (javathread)->get_thread_name(); \
134 len = strlen(name); \
135 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
136 name, len, \
137 java_lang_Thread::thread_id((javathread)->threadObj()), \
138 (javathread)->osthread()->thread_id(), \
139 java_lang_Thread::is_daemon((javathread)->threadObj())); \
140 }
141
142 #else /* USDT2 */
143
144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
146
147 #define DTRACE_THREAD_PROBE(probe, javathread) \
148 { \
149 ResourceMark rm(this); \
150 int len = 0; \
151 const char* name = (javathread)->get_thread_name(); \
152 len = strlen(name); \
153 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
154 (char *) name, len, \
155 java_lang_Thread::thread_id((javathread)->threadObj()), \
156 (uintptr_t) (javathread)->osthread()->thread_id(), \
157 java_lang_Thread::is_daemon((javathread)->threadObj())); \
158 }
159
160 #endif /* USDT2 */
161
162 #else // ndef DTRACE_ENABLED
163
164 #define DTRACE_THREAD_PROBE(probe, javathread)
165
166 #endif // ndef DTRACE_ENABLED
167
168
169 // Class hierarchy
170 // - Thread
171 // - VMThread
172 // - WatcherThread
173 // - ConcurrentMarkSweepThread
174 // - JavaThread
175 // - CompilerThread
176
177 // ======= Thread ========
178 // Support for forcing alignment of thread objects for biased locking
179 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
180 if (UseBiasedLocking) {
181 const int alignment = markOopDesc::biased_lock_alignment;
182 size_t aligned_size = size + (alignment - sizeof(intptr_t));
183 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
184 : AllocateHeap(aligned_size, flags, CURRENT_PC,
185 AllocFailStrategy::RETURN_NULL);
186 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
187 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
188 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
189 "JavaThread alignment code overflowed allocated storage");
190 if (TraceBiasedLocking) {
191 if (aligned_addr != real_malloc_addr)
192 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
193 real_malloc_addr, aligned_addr);
194 }
195 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
196 return aligned_addr;
197 } else {
198 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
199 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
200 }
201 }
202
203 void Thread::operator delete(void* p) {
204 if (UseBiasedLocking) {
205 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
206 FreeHeap(real_malloc_addr, mtThread);
207 } else {
208 FreeHeap(p, mtThread);
209 }
210 }
211
212
213 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
214 // JavaThread
215
216
217 Thread::Thread() {
218 // stack and get_thread
219 set_stack_base(NULL);
220 set_stack_size(0);
221 set_self_raw_id(0);
222 set_lgrp_id(-1);
223
224 // allocated data structures
225 set_osthread(NULL);
226 set_resource_area(new (mtThread)ResourceArea());
227 DEBUG_ONLY(_current_resource_mark = NULL;)
228 set_handle_area(new (mtThread) HandleArea(NULL));
229 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
230 set_active_handles(NULL);
231 set_free_handle_block(NULL);
232 set_last_handle_mark(NULL);
233
234 // This initial value ==> never claimed.
235 _oops_do_parity = 0;
236
237 // the handle mark links itself to last_handle_mark
238 new HandleMark(this);
239
240 // plain initialization
241 debug_only(_owned_locks = NULL;)
242 debug_only(_allow_allocation_count = 0;)
243 NOT_PRODUCT(_allow_safepoint_count = 0;)
244 NOT_PRODUCT(_skip_gcalot = false;)
245 _jvmti_env_iteration_count = 0;
246 set_allocated_bytes(0);
247 _vm_operation_started_count = 0;
248 _vm_operation_completed_count = 0;
249 _current_pending_monitor = NULL;
250 _current_pending_monitor_is_from_java = true;
251 _current_waiting_monitor = NULL;
252 _num_nested_signal = 0;
253 omFreeList = NULL ;
254 omFreeCount = 0 ;
255 omFreeProvision = 32 ;
256 omInUseList = NULL ;
257 omInUseCount = 0 ;
258
259 #ifdef ASSERT
260 _visited_for_critical_count = false;
261 #endif
262
263 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
264 _suspend_flags = 0;
265
266 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
267 _hashStateX = os::random() ;
268 _hashStateY = 842502087 ;
269 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
270 _hashStateW = 273326509 ;
271
272 _OnTrap = 0 ;
273 _schedctl = NULL ;
274 _Stalled = 0 ;
275 _TypeTag = 0x2BAD ;
276
277 // Many of the following fields are effectively final - immutable
278 // Note that nascent threads can't use the Native Monitor-Mutex
279 // construct until the _MutexEvent is initialized ...
280 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
281 // we might instead use a stack of ParkEvents that we could provision on-demand.
282 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
283 // and ::Release()
284 _ParkEvent = ParkEvent::Allocate (this) ;
285 _SleepEvent = ParkEvent::Allocate (this) ;
286 _MutexEvent = ParkEvent::Allocate (this) ;
287 _MuxEvent = ParkEvent::Allocate (this) ;
288
289 #ifdef CHECK_UNHANDLED_OOPS
290 if (CheckUnhandledOops) {
291 _unhandled_oops = new UnhandledOops(this);
292 }
293 #endif // CHECK_UNHANDLED_OOPS
294 #ifdef ASSERT
295 if (UseBiasedLocking) {
296 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
297 assert(this == _real_malloc_address ||
298 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
299 "bug in forced alignment of thread objects");
300 }
301 #endif /* ASSERT */
302 }
303
304 void Thread::initialize_thread_local_storage() {
305 // Note: Make sure this method only calls
306 // non-blocking operations. Otherwise, it might not work
307 // with the thread-startup/safepoint interaction.
308
309 // During Java thread startup, safepoint code should allow this
310 // method to complete because it may need to allocate memory to
311 // store information for the new thread.
312
313 // initialize structure dependent on thread local storage
314 ThreadLocalStorage::set_thread(this);
315 }
316
317 void Thread::record_stack_base_and_size() {
318 set_stack_base(os::current_stack_base());
319 set_stack_size(os::current_stack_size());
320 if (is_Java_thread()) {
321 ((JavaThread*) this)->set_stack_overflow_limit();
322 }
323 // CR 7190089: on Solaris, primordial thread's stack is adjusted
324 // in initialize_thread(). Without the adjustment, stack size is
325 // incorrect if stack is set to unlimited (ulimit -s unlimited).
326 // So far, only Solaris has real implementation of initialize_thread().
327 //
328 // set up any platform-specific state.
329 os::initialize_thread(this);
330
331 #if INCLUDE_NMT
332 // record thread's native stack, stack grows downward
333 address stack_low_addr = stack_base() - stack_size();
334 MemTracker::record_thread_stack(stack_low_addr, stack_size());
335 #endif // INCLUDE_NMT
336 }
337
338
339 Thread::~Thread() {
340 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
341 ObjectSynchronizer::omFlush (this) ;
342
343 EVENT_THREAD_DESTRUCT(this);
344
345 // stack_base can be NULL if the thread is never started or exited before
346 // record_stack_base_and_size called. Although, we would like to ensure
347 // that all started threads do call record_stack_base_and_size(), there is
348 // not proper way to enforce that.
349 #if INCLUDE_NMT
350 if (_stack_base != NULL) {
351 address low_stack_addr = stack_base() - stack_size();
352 MemTracker::release_thread_stack(low_stack_addr, stack_size());
353 #ifdef ASSERT
354 set_stack_base(NULL);
355 #endif
356 }
357 #endif // INCLUDE_NMT
358
359 // deallocate data structures
360 delete resource_area();
361 // since the handle marks are using the handle area, we have to deallocated the root
362 // handle mark before deallocating the thread's handle area,
363 assert(last_handle_mark() != NULL, "check we have an element");
364 delete last_handle_mark();
365 assert(last_handle_mark() == NULL, "check we have reached the end");
366
367 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
368 // We NULL out the fields for good hygiene.
369 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
370 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
371 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
372 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
373
374 delete handle_area();
375 delete metadata_handles();
376
377 // osthread() can be NULL, if creation of thread failed.
378 if (osthread() != NULL) os::free_thread(osthread());
379
380 delete _SR_lock;
381
382 // clear thread local storage if the Thread is deleting itself
383 if (this == Thread::current()) {
384 ThreadLocalStorage::set_thread(NULL);
385 } else {
386 // In the case where we're not the current thread, invalidate all the
387 // caches in case some code tries to get the current thread or the
388 // thread that was destroyed, and gets stale information.
389 ThreadLocalStorage::invalidate_all();
390 }
391 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
392 }
393
394 // NOTE: dummy function for assertion purpose.
395 void Thread::run() {
396 ShouldNotReachHere();
397 }
398
399 #ifdef ASSERT
400 // Private method to check for dangling thread pointer
401 void check_for_dangling_thread_pointer(Thread *thread) {
402 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
403 "possibility of dangling Thread pointer");
404 }
405 #endif
406
407
408 #ifndef PRODUCT
409 // Tracing method for basic thread operations
410 void Thread::trace(const char* msg, const Thread* const thread) {
411 if (!TraceThreadEvents) return;
412 ResourceMark rm;
413 ThreadCritical tc;
414 const char *name = "non-Java thread";
415 int prio = -1;
416 if (thread->is_Java_thread()
417 && !thread->is_Compiler_thread()) {
418 // The Threads_lock must be held to get information about
419 // this thread but may not be in some situations when
420 // tracing thread events.
421 bool release_Threads_lock = false;
422 if (!Threads_lock->owned_by_self()) {
423 Threads_lock->lock();
424 release_Threads_lock = true;
425 }
426 JavaThread* jt = (JavaThread *)thread;
427 name = (char *)jt->get_thread_name();
428 oop thread_oop = jt->threadObj();
429 if (thread_oop != NULL) {
430 prio = java_lang_Thread::priority(thread_oop);
431 }
432 if (release_Threads_lock) {
433 Threads_lock->unlock();
434 }
435 }
436 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
437 }
438 #endif
439
440
441 ThreadPriority Thread::get_priority(const Thread* const thread) {
442 trace("get priority", thread);
443 ThreadPriority priority;
444 // Can return an error!
445 (void)os::get_priority(thread, priority);
446 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
447 return priority;
448 }
449
450 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
451 trace("set priority", thread);
452 debug_only(check_for_dangling_thread_pointer(thread);)
453 // Can return an error!
454 (void)os::set_priority(thread, priority);
455 }
456
457
458 void Thread::start(Thread* thread) {
459 trace("start", thread);
460 // Start is different from resume in that its safety is guaranteed by context or
461 // being called from a Java method synchronized on the Thread object.
462 if (!DisableStartThread) {
463 if (thread->is_Java_thread()) {
464 // Initialize the thread state to RUNNABLE before starting this thread.
465 // Can not set it after the thread started because we do not know the
466 // exact thread state at that time. It could be in MONITOR_WAIT or
467 // in SLEEPING or some other state.
468 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
469 java_lang_Thread::RUNNABLE);
470 }
471 os::start_thread(thread);
472 }
473 }
474
475 // Enqueue a VM_Operation to do the job for us - sometime later
476 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
477 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
478 VMThread::execute(vm_stop);
479 }
480
481
482 //
483 // Check if an external suspend request has completed (or has been
484 // cancelled). Returns true if the thread is externally suspended and
485 // false otherwise.
486 //
487 // The bits parameter returns information about the code path through
488 // the routine. Useful for debugging:
489 //
490 // set in is_ext_suspend_completed():
491 // 0x00000001 - routine was entered
492 // 0x00000010 - routine return false at end
493 // 0x00000100 - thread exited (return false)
494 // 0x00000200 - suspend request cancelled (return false)
495 // 0x00000400 - thread suspended (return true)
496 // 0x00001000 - thread is in a suspend equivalent state (return true)
497 // 0x00002000 - thread is native and walkable (return true)
498 // 0x00004000 - thread is native_trans and walkable (needed retry)
499 //
500 // set in wait_for_ext_suspend_completion():
501 // 0x00010000 - routine was entered
502 // 0x00020000 - suspend request cancelled before loop (return false)
503 // 0x00040000 - thread suspended before loop (return true)
504 // 0x00080000 - suspend request cancelled in loop (return false)
505 // 0x00100000 - thread suspended in loop (return true)
506 // 0x00200000 - suspend not completed during retry loop (return false)
507 //
508
509 // Helper class for tracing suspend wait debug bits.
510 //
511 // 0x00000100 indicates that the target thread exited before it could
512 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
513 // 0x00080000 each indicate a cancelled suspend request so they don't
514 // count as wait failures either.
515 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
516
517 class TraceSuspendDebugBits : public StackObj {
518 private:
519 JavaThread * jt;
520 bool is_wait;
521 bool called_by_wait; // meaningful when !is_wait
522 uint32_t * bits;
523
524 public:
525 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
526 uint32_t *_bits) {
527 jt = _jt;
528 is_wait = _is_wait;
529 called_by_wait = _called_by_wait;
530 bits = _bits;
531 }
532
533 ~TraceSuspendDebugBits() {
534 if (!is_wait) {
535 #if 1
536 // By default, don't trace bits for is_ext_suspend_completed() calls.
537 // That trace is very chatty.
538 return;
539 #else
540 if (!called_by_wait) {
541 // If tracing for is_ext_suspend_completed() is enabled, then only
542 // trace calls to it from wait_for_ext_suspend_completion()
543 return;
544 }
545 #endif
546 }
547
548 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
549 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
550 MutexLocker ml(Threads_lock); // needed for get_thread_name()
551 ResourceMark rm;
552
553 tty->print_cr(
554 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
555 jt->get_thread_name(), *bits);
556
557 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
558 }
559 }
560 }
561 };
562 #undef DEBUG_FALSE_BITS
563
564
565 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
566 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
567
568 bool did_trans_retry = false; // only do thread_in_native_trans retry once
569 bool do_trans_retry; // flag to force the retry
570
571 *bits |= 0x00000001;
572
573 do {
574 do_trans_retry = false;
575
576 if (is_exiting()) {
577 // Thread is in the process of exiting. This is always checked
578 // first to reduce the risk of dereferencing a freed JavaThread.
579 *bits |= 0x00000100;
580 return false;
581 }
582
583 if (!is_external_suspend()) {
584 // Suspend request is cancelled. This is always checked before
585 // is_ext_suspended() to reduce the risk of a rogue resume
586 // confusing the thread that made the suspend request.
587 *bits |= 0x00000200;
588 return false;
589 }
590
591 if (is_ext_suspended()) {
592 // thread is suspended
593 *bits |= 0x00000400;
594 return true;
595 }
596
597 // Now that we no longer do hard suspends of threads running
598 // native code, the target thread can be changing thread state
599 // while we are in this routine:
600 //
601 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
602 //
603 // We save a copy of the thread state as observed at this moment
604 // and make our decision about suspend completeness based on the
605 // copy. This closes the race where the thread state is seen as
606 // _thread_in_native_trans in the if-thread_blocked check, but is
607 // seen as _thread_blocked in if-thread_in_native_trans check.
608 JavaThreadState save_state = thread_state();
609
610 if (save_state == _thread_blocked && is_suspend_equivalent()) {
611 // If the thread's state is _thread_blocked and this blocking
612 // condition is known to be equivalent to a suspend, then we can
613 // consider the thread to be externally suspended. This means that
614 // the code that sets _thread_blocked has been modified to do
615 // self-suspension if the blocking condition releases. We also
616 // used to check for CONDVAR_WAIT here, but that is now covered by
617 // the _thread_blocked with self-suspension check.
618 //
619 // Return true since we wouldn't be here unless there was still an
620 // external suspend request.
621 *bits |= 0x00001000;
622 return true;
623 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
624 // Threads running native code will self-suspend on native==>VM/Java
625 // transitions. If its stack is walkable (should always be the case
626 // unless this function is called before the actual java_suspend()
627 // call), then the wait is done.
628 *bits |= 0x00002000;
629 return true;
630 } else if (!called_by_wait && !did_trans_retry &&
631 save_state == _thread_in_native_trans &&
632 frame_anchor()->walkable()) {
633 // The thread is transitioning from thread_in_native to another
634 // thread state. check_safepoint_and_suspend_for_native_trans()
635 // will force the thread to self-suspend. If it hasn't gotten
636 // there yet we may have caught the thread in-between the native
637 // code check above and the self-suspend. Lucky us. If we were
638 // called by wait_for_ext_suspend_completion(), then it
639 // will be doing the retries so we don't have to.
640 //
641 // Since we use the saved thread state in the if-statement above,
642 // there is a chance that the thread has already transitioned to
643 // _thread_blocked by the time we get here. In that case, we will
644 // make a single unnecessary pass through the logic below. This
645 // doesn't hurt anything since we still do the trans retry.
646
647 *bits |= 0x00004000;
648
649 // Once the thread leaves thread_in_native_trans for another
650 // thread state, we break out of this retry loop. We shouldn't
651 // need this flag to prevent us from getting back here, but
652 // sometimes paranoia is good.
653 did_trans_retry = true;
654
655 // We wait for the thread to transition to a more usable state.
656 for (int i = 1; i <= SuspendRetryCount; i++) {
657 // We used to do an "os::yield_all(i)" call here with the intention
658 // that yielding would increase on each retry. However, the parameter
659 // is ignored on Linux which means the yield didn't scale up. Waiting
660 // on the SR_lock below provides a much more predictable scale up for
661 // the delay. It also provides a simple/direct point to check for any
662 // safepoint requests from the VMThread
663
664 // temporarily drops SR_lock while doing wait with safepoint check
665 // (if we're a JavaThread - the WatcherThread can also call this)
666 // and increase delay with each retry
667 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
668
669 // check the actual thread state instead of what we saved above
670 if (thread_state() != _thread_in_native_trans) {
671 // the thread has transitioned to another thread state so
672 // try all the checks (except this one) one more time.
673 do_trans_retry = true;
674 break;
675 }
676 } // end retry loop
677
678
679 }
680 } while (do_trans_retry);
681
682 *bits |= 0x00000010;
683 return false;
684 }
685
686 //
687 // Wait for an external suspend request to complete (or be cancelled).
688 // Returns true if the thread is externally suspended and false otherwise.
689 //
690 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
691 uint32_t *bits) {
692 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
693 false /* !called_by_wait */, bits);
694
695 // local flag copies to minimize SR_lock hold time
696 bool is_suspended;
697 bool pending;
698 uint32_t reset_bits;
699
700 // set a marker so is_ext_suspend_completed() knows we are the caller
701 *bits |= 0x00010000;
702
703 // We use reset_bits to reinitialize the bits value at the top of
704 // each retry loop. This allows the caller to make use of any
705 // unused bits for their own marking purposes.
706 reset_bits = *bits;
707
708 {
709 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
710 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
711 delay, bits);
712 pending = is_external_suspend();
713 }
714 // must release SR_lock to allow suspension to complete
715
716 if (!pending) {
717 // A cancelled suspend request is the only false return from
718 // is_ext_suspend_completed() that keeps us from entering the
719 // retry loop.
720 *bits |= 0x00020000;
721 return false;
722 }
723
724 if (is_suspended) {
725 *bits |= 0x00040000;
726 return true;
727 }
728
729 for (int i = 1; i <= retries; i++) {
730 *bits = reset_bits; // reinit to only track last retry
731
732 // We used to do an "os::yield_all(i)" call here with the intention
733 // that yielding would increase on each retry. However, the parameter
734 // is ignored on Linux which means the yield didn't scale up. Waiting
735 // on the SR_lock below provides a much more predictable scale up for
736 // the delay. It also provides a simple/direct point to check for any
737 // safepoint requests from the VMThread
738
739 {
740 MutexLocker ml(SR_lock());
741 // wait with safepoint check (if we're a JavaThread - the WatcherThread
742 // can also call this) and increase delay with each retry
743 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
744
745 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
746 delay, bits);
747
748 // It is possible for the external suspend request to be cancelled
749 // (by a resume) before the actual suspend operation is completed.
750 // Refresh our local copy to see if we still need to wait.
751 pending = is_external_suspend();
752 }
753
754 if (!pending) {
755 // A cancelled suspend request is the only false return from
756 // is_ext_suspend_completed() that keeps us from staying in the
757 // retry loop.
758 *bits |= 0x00080000;
759 return false;
760 }
761
762 if (is_suspended) {
763 *bits |= 0x00100000;
764 return true;
765 }
766 } // end retry loop
767
768 // thread did not suspend after all our retries
769 *bits |= 0x00200000;
770 return false;
771 }
772
773 #ifndef PRODUCT
774 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
775
776 // This should not need to be atomic as the only way for simultaneous
777 // updates is via interrupts. Even then this should be rare or non-existant
778 // and we don't care that much anyway.
779
780 int index = _jmp_ring_index;
781 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
782 _jmp_ring[index]._target = (intptr_t) target;
783 _jmp_ring[index]._instruction = (intptr_t) instr;
784 _jmp_ring[index]._file = file;
785 _jmp_ring[index]._line = line;
786 }
787 #endif /* PRODUCT */
788
789 // Called by flat profiler
790 // Callers have already called wait_for_ext_suspend_completion
791 // The assertion for that is currently too complex to put here:
792 bool JavaThread::profile_last_Java_frame(frame* _fr) {
793 bool gotframe = false;
794 // self suspension saves needed state.
795 if (has_last_Java_frame() && _anchor.walkable()) {
796 *_fr = pd_last_frame();
797 gotframe = true;
798 }
799 return gotframe;
800 }
801
802 void Thread::interrupt(Thread* thread) {
803 trace("interrupt", thread);
804 debug_only(check_for_dangling_thread_pointer(thread);)
805 os::interrupt(thread);
806 }
807
808 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
809 trace("is_interrupted", thread);
810 debug_only(check_for_dangling_thread_pointer(thread);)
811 // Note: If clear_interrupted==false, this simply fetches and
812 // returns the value of the field osthread()->interrupted().
813 return os::is_interrupted(thread, clear_interrupted);
814 }
815
816
817 // GC Support
818 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
819 jint thread_parity = _oops_do_parity;
820 if (thread_parity != strong_roots_parity) {
821 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
822 if (res == thread_parity) {
823 return true;
824 } else {
825 guarantee(res == strong_roots_parity, "Or else what?");
826 assert(SharedHeap::heap()->workers()->active_workers() > 0,
827 "Should only fail when parallel.");
828 return false;
829 }
830 }
831 assert(SharedHeap::heap()->workers()->active_workers() > 0,
832 "Should only fail when parallel.");
833 return false;
834 }
835
836 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
837 active_handles()->oops_do(f);
838 // Do oop for ThreadShadow
839 f->do_oop((oop*)&_pending_exception);
840 handle_area()->oops_do(f);
841 }
842
843 void Thread::nmethods_do(CodeBlobClosure* cf) {
844 // no nmethods in a generic thread...
845 }
846
847 void Thread::metadata_do(void f(Metadata*)) {
848 if (metadata_handles() != NULL) {
849 for (int i = 0; i< metadata_handles()->length(); i++) {
850 f(metadata_handles()->at(i));
851 }
852 }
853 }
854
855 void Thread::print_on(outputStream* st) const {
856 // get_priority assumes osthread initialized
857 if (osthread() != NULL) {
858 int os_prio;
859 if (os::get_native_priority(this, &os_prio) == OS_OK) {
860 st->print("os_prio=%d ", os_prio);
861 }
862 st->print("tid=" INTPTR_FORMAT " ", this);
863 ext().print_on(st);
864 osthread()->print_on(st);
865 }
866 debug_only(if (WizardMode) print_owned_locks_on(st);)
867 }
868
869 // Thread::print_on_error() is called by fatal error handler. Don't use
870 // any lock or allocate memory.
871 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
872 if (is_VM_thread()) st->print("VMThread");
873 else if (is_Compiler_thread()) st->print("CompilerThread");
874 else if (is_Java_thread()) st->print("JavaThread");
875 else if (is_GC_task_thread()) st->print("GCTaskThread");
876 else if (is_Watcher_thread()) st->print("WatcherThread");
877 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
878 else st->print("Thread");
879
880 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
881 _stack_base - _stack_size, _stack_base);
882
883 if (osthread()) {
884 st->print(" [id=%d]", osthread()->thread_id());
885 }
886 }
887
888 #ifdef ASSERT
889 void Thread::print_owned_locks_on(outputStream* st) const {
890 Monitor *cur = _owned_locks;
891 if (cur == NULL) {
892 st->print(" (no locks) ");
893 } else {
894 st->print_cr(" Locks owned:");
895 while(cur) {
896 cur->print_on(st);
897 cur = cur->next();
898 }
899 }
900 }
901
902 static int ref_use_count = 0;
903
904 bool Thread::owns_locks_but_compiled_lock() const {
905 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
906 if (cur != Compile_lock) return true;
907 }
908 return false;
909 }
910
911
912 #endif
913
914 #ifndef PRODUCT
915
916 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
917 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
918 // no threads which allow_vm_block's are held
919 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
920 // Check if current thread is allowed to block at a safepoint
921 if (!(_allow_safepoint_count == 0))
922 fatal("Possible safepoint reached by thread that does not allow it");
923 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
924 fatal("LEAF method calling lock?");
925 }
926
927 #ifdef ASSERT
928 if (potential_vm_operation && is_Java_thread()
929 && !Universe::is_bootstrapping()) {
930 // Make sure we do not hold any locks that the VM thread also uses.
931 // This could potentially lead to deadlocks
932 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
933 // Threads_lock is special, since the safepoint synchronization will not start before this is
934 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
935 // since it is used to transfer control between JavaThreads and the VMThread
936 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
937 if ( (cur->allow_vm_block() &&
938 cur != Threads_lock &&
939 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
940 cur != VMOperationRequest_lock &&
941 cur != VMOperationQueue_lock) ||
942 cur->rank() == Mutex::special) {
943 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
944 }
945 }
946 }
947
948 if (GCALotAtAllSafepoints) {
949 // We could enter a safepoint here and thus have a gc
950 InterfaceSupport::check_gc_alot();
951 }
952 #endif
953 }
954 #endif
955
956 bool Thread::is_in_stack(address adr) const {
957 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
958 address end = os::current_stack_pointer();
959 // Allow non Java threads to call this without stack_base
960 if (_stack_base == NULL) return true;
961 if (stack_base() >= adr && adr >= end) return true;
962
963 return false;
964 }
965
966
967 bool Thread::is_in_usable_stack(address adr) const {
968 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
969 size_t usable_stack_size = _stack_size - stack_guard_size;
970
971 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
972 }
973
974
975 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
976 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
977 // used for compilation in the future. If that change is made, the need for these methods
978 // should be revisited, and they should be removed if possible.
979
980 bool Thread::is_lock_owned(address adr) const {
981 return on_local_stack(adr);
982 }
983
984 bool Thread::set_as_starting_thread() {
985 // NOTE: this must be called inside the main thread.
986 return os::create_main_thread((JavaThread*)this);
987 }
988
989 static void initialize_class(Symbol* class_name, TRAPS) {
990 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
991 InstanceKlass::cast(klass)->initialize(CHECK);
992 }
993
994
995 // Creates the initial ThreadGroup
996 static Handle create_initial_thread_group(TRAPS) {
997 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
998 instanceKlassHandle klass (THREAD, k);
999
1000 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1001 {
1002 JavaValue result(T_VOID);
1003 JavaCalls::call_special(&result,
1004 system_instance,
1005 klass,
1006 vmSymbols::object_initializer_name(),
1007 vmSymbols::void_method_signature(),
1008 CHECK_NH);
1009 }
1010 Universe::set_system_thread_group(system_instance());
1011
1012 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1013 {
1014 JavaValue result(T_VOID);
1015 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1016 JavaCalls::call_special(&result,
1017 main_instance,
1018 klass,
1019 vmSymbols::object_initializer_name(),
1020 vmSymbols::threadgroup_string_void_signature(),
1021 system_instance,
1022 string,
1023 CHECK_NH);
1024 }
1025 return main_instance;
1026 }
1027
1028 // Creates the initial Thread
1029 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1030 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1031 instanceKlassHandle klass (THREAD, k);
1032 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1033
1034 java_lang_Thread::set_thread(thread_oop(), thread);
1035 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1036 thread->set_threadObj(thread_oop());
1037
1038 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1039
1040 JavaValue result(T_VOID);
1041 JavaCalls::call_special(&result, thread_oop,
1042 klass,
1043 vmSymbols::object_initializer_name(),
1044 vmSymbols::threadgroup_string_void_signature(),
1045 thread_group,
1046 string,
1047 CHECK_NULL);
1048 return thread_oop();
1049 }
1050
1051 static void call_initializeSystemClass(TRAPS) {
1052 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1053 instanceKlassHandle klass (THREAD, k);
1054
1055 JavaValue result(T_VOID);
1056 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1057 vmSymbols::void_method_signature(), CHECK);
1058 }
1059
1060 char java_runtime_name[128] = "";
1061 char java_runtime_version[128] = "";
1062
1063 // extract the JRE name from sun.misc.Version.java_runtime_name
1064 static const char* get_java_runtime_name(TRAPS) {
1065 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1066 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1067 fieldDescriptor fd;
1068 bool found = k != NULL &&
1069 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1070 vmSymbols::string_signature(), &fd);
1071 if (found) {
1072 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1073 if (name_oop == NULL)
1074 return NULL;
1075 const char* name = java_lang_String::as_utf8_string(name_oop,
1076 java_runtime_name,
1077 sizeof(java_runtime_name));
1078 return name;
1079 } else {
1080 return NULL;
1081 }
1082 }
1083
1084 // extract the JRE version from sun.misc.Version.java_runtime_version
1085 static const char* get_java_runtime_version(TRAPS) {
1086 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1087 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1088 fieldDescriptor fd;
1089 bool found = k != NULL &&
1090 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1091 vmSymbols::string_signature(), &fd);
1092 if (found) {
1093 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1094 if (name_oop == NULL)
1095 return NULL;
1096 const char* name = java_lang_String::as_utf8_string(name_oop,
1097 java_runtime_version,
1098 sizeof(java_runtime_version));
1099 return name;
1100 } else {
1101 return NULL;
1102 }
1103 }
1104
1105 // General purpose hook into Java code, run once when the VM is initialized.
1106 // The Java library method itself may be changed independently from the VM.
1107 static void call_postVMInitHook(TRAPS) {
1108 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1109 instanceKlassHandle klass (THREAD, k);
1110 if (klass.not_null()) {
1111 JavaValue result(T_VOID);
1112 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1113 vmSymbols::void_method_signature(),
1114 CHECK);
1115 }
1116 }
1117
1118 static void reset_vm_info_property(TRAPS) {
1119 // the vm info string
1120 ResourceMark rm(THREAD);
1121 const char *vm_info = VM_Version::vm_info_string();
1122
1123 // java.lang.System class
1124 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1125 instanceKlassHandle klass (THREAD, k);
1126
1127 // setProperty arguments
1128 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1129 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1130
1131 // return value
1132 JavaValue r(T_OBJECT);
1133
1134 // public static String setProperty(String key, String value);
1135 JavaCalls::call_static(&r,
1136 klass,
1137 vmSymbols::setProperty_name(),
1138 vmSymbols::string_string_string_signature(),
1139 key_str,
1140 value_str,
1141 CHECK);
1142 }
1143
1144
1145 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1146 assert(thread_group.not_null(), "thread group should be specified");
1147 assert(threadObj() == NULL, "should only create Java thread object once");
1148
1149 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1150 instanceKlassHandle klass (THREAD, k);
1151 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1152
1153 java_lang_Thread::set_thread(thread_oop(), this);
1154 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1155 set_threadObj(thread_oop());
1156
1157 JavaValue result(T_VOID);
1158 if (thread_name != NULL) {
1159 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1160 // Thread gets assigned specified name and null target
1161 JavaCalls::call_special(&result,
1162 thread_oop,
1163 klass,
1164 vmSymbols::object_initializer_name(),
1165 vmSymbols::threadgroup_string_void_signature(),
1166 thread_group, // Argument 1
1167 name, // Argument 2
1168 THREAD);
1169 } else {
1170 // Thread gets assigned name "Thread-nnn" and null target
1171 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1172 JavaCalls::call_special(&result,
1173 thread_oop,
1174 klass,
1175 vmSymbols::object_initializer_name(),
1176 vmSymbols::threadgroup_runnable_void_signature(),
1177 thread_group, // Argument 1
1178 Handle(), // Argument 2
1179 THREAD);
1180 }
1181
1182
1183 if (daemon) {
1184 java_lang_Thread::set_daemon(thread_oop());
1185 }
1186
1187 if (HAS_PENDING_EXCEPTION) {
1188 return;
1189 }
1190
1191 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1192 Handle threadObj(this, this->threadObj());
1193
1194 JavaCalls::call_special(&result,
1195 thread_group,
1196 group,
1197 vmSymbols::add_method_name(),
1198 vmSymbols::thread_void_signature(),
1199 threadObj, // Arg 1
1200 THREAD);
1201
1202
1203 }
1204
1205 // NamedThread -- non-JavaThread subclasses with multiple
1206 // uniquely named instances should derive from this.
1207 NamedThread::NamedThread() : Thread() {
1208 _name = NULL;
1209 _processed_thread = NULL;
1210 }
1211
1212 NamedThread::~NamedThread() {
1213 if (_name != NULL) {
1214 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1215 _name = NULL;
1216 }
1217 }
1218
1219 void NamedThread::set_name(const char* format, ...) {
1220 guarantee(_name == NULL, "Only get to set name once.");
1221 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1222 guarantee(_name != NULL, "alloc failure");
1223 va_list ap;
1224 va_start(ap, format);
1225 jio_vsnprintf(_name, max_name_len, format, ap);
1226 va_end(ap);
1227 }
1228
1229 // ======= WatcherThread ========
1230
1231 // The watcher thread exists to simulate timer interrupts. It should
1232 // be replaced by an abstraction over whatever native support for
1233 // timer interrupts exists on the platform.
1234
1235 WatcherThread* WatcherThread::_watcher_thread = NULL;
1236 bool WatcherThread::_startable = false;
1237 volatile bool WatcherThread::_should_terminate = false;
1238
1239 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1240 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1241 if (os::create_thread(this, os::watcher_thread)) {
1242 _watcher_thread = this;
1243
1244 // Set the watcher thread to the highest OS priority which should not be
1245 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1246 // is created. The only normal thread using this priority is the reference
1247 // handler thread, which runs for very short intervals only.
1248 // If the VMThread's priority is not lower than the WatcherThread profiling
1249 // will be inaccurate.
1250 os::set_priority(this, MaxPriority);
1251 if (!DisableStartThread) {
1252 os::start_thread(this);
1253 }
1254 }
1255 }
1256
1257 int WatcherThread::sleep() const {
1258 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1259
1260 // remaining will be zero if there are no tasks,
1261 // causing the WatcherThread to sleep until a task is
1262 // enrolled
1263 int remaining = PeriodicTask::time_to_wait();
1264 int time_slept = 0;
1265
1266 // we expect this to timeout - we only ever get unparked when
1267 // we should terminate or when a new task has been enrolled
1268 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1269
1270 jlong time_before_loop = os::javaTimeNanos();
1271
1272 for (;;) {
1273 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1274 jlong now = os::javaTimeNanos();
1275
1276 if (remaining == 0) {
1277 // if we didn't have any tasks we could have waited for a long time
1278 // consider the time_slept zero and reset time_before_loop
1279 time_slept = 0;
1280 time_before_loop = now;
1281 } else {
1282 // need to recalulate since we might have new tasks in _tasks
1283 time_slept = (int) ((now - time_before_loop) / 1000000);
1284 }
1285
1286 // Change to task list or spurious wakeup of some kind
1287 if (timedout || _should_terminate) {
1288 break;
1289 }
1290
1291 remaining = PeriodicTask::time_to_wait();
1292 if (remaining == 0) {
1293 // Last task was just disenrolled so loop around and wait until
1294 // another task gets enrolled
1295 continue;
1296 }
1297
1298 remaining -= time_slept;
1299 if (remaining <= 0)
1300 break;
1301 }
1302
1303 return time_slept;
1304 }
1305
1306 void WatcherThread::run() {
1307 assert(this == watcher_thread(), "just checking");
1308
1309 this->record_stack_base_and_size();
1310 this->initialize_thread_local_storage();
1311 this->set_active_handles(JNIHandleBlock::allocate_block());
1312 while(!_should_terminate) {
1313 assert(watcher_thread() == Thread::current(), "thread consistency check");
1314 assert(watcher_thread() == this, "thread consistency check");
1315
1316 // Calculate how long it'll be until the next PeriodicTask work
1317 // should be done, and sleep that amount of time.
1318 int time_waited = sleep();
1319
1320 if (is_error_reported()) {
1321 // A fatal error has happened, the error handler(VMError::report_and_die)
1322 // should abort JVM after creating an error log file. However in some
1323 // rare cases, the error handler itself might deadlock. Here we try to
1324 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1325 //
1326 // This code is in WatcherThread because WatcherThread wakes up
1327 // periodically so the fatal error handler doesn't need to do anything;
1328 // also because the WatcherThread is less likely to crash than other
1329 // threads.
1330
1331 for (;;) {
1332 if (!ShowMessageBoxOnError
1333 && (OnError == NULL || OnError[0] == '\0')
1334 && Arguments::abort_hook() == NULL) {
1335 os::sleep(this, 2 * 60 * 1000, false);
1336 fdStream err(defaultStream::output_fd());
1337 err.print_raw_cr("# [ timer expired, abort... ]");
1338 // skip atexit/vm_exit/vm_abort hooks
1339 os::die();
1340 }
1341
1342 // Wake up 5 seconds later, the fatal handler may reset OnError or
1343 // ShowMessageBoxOnError when it is ready to abort.
1344 os::sleep(this, 5 * 1000, false);
1345 }
1346 }
1347
1348 PeriodicTask::real_time_tick(time_waited);
1349 }
1350
1351 // Signal that it is terminated
1352 {
1353 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1354 _watcher_thread = NULL;
1355 Terminator_lock->notify();
1356 }
1357
1358 // Thread destructor usually does this..
1359 ThreadLocalStorage::set_thread(NULL);
1360 }
1361
1362 void WatcherThread::start() {
1363 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1364
1365 if (watcher_thread() == NULL && _startable) {
1366 _should_terminate = false;
1367 // Create the single instance of WatcherThread
1368 new WatcherThread();
1369 }
1370 }
1371
1372 void WatcherThread::make_startable() {
1373 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1374 _startable = true;
1375 }
1376
1377 void WatcherThread::stop() {
1378 {
1379 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1380 _should_terminate = true;
1381 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1382
1383 WatcherThread* watcher = watcher_thread();
1384 if (watcher != NULL)
1385 watcher->unpark();
1386 }
1387
1388 // it is ok to take late safepoints here, if needed
1389 MutexLocker mu(Terminator_lock);
1390
1391 while(watcher_thread() != NULL) {
1392 // This wait should make safepoint checks, wait without a timeout,
1393 // and wait as a suspend-equivalent condition.
1394 //
1395 // Note: If the FlatProfiler is running, then this thread is waiting
1396 // for the WatcherThread to terminate and the WatcherThread, via the
1397 // FlatProfiler task, is waiting for the external suspend request on
1398 // this thread to complete. wait_for_ext_suspend_completion() will
1399 // eventually timeout, but that takes time. Making this wait a
1400 // suspend-equivalent condition solves that timeout problem.
1401 //
1402 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1403 Mutex::_as_suspend_equivalent_flag);
1404 }
1405 }
1406
1407 void WatcherThread::unpark() {
1408 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1409 PeriodicTask_lock->notify();
1410 }
1411
1412 void WatcherThread::print_on(outputStream* st) const {
1413 st->print("\"%s\" ", name());
1414 Thread::print_on(st);
1415 st->cr();
1416 }
1417
1418 // ======= JavaThread ========
1419
1420 // A JavaThread is a normal Java thread
1421
1422 void JavaThread::initialize() {
1423 // Initialize fields
1424
1425 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1426 set_claimed_par_id(UINT_MAX);
1427
1428 set_saved_exception_pc(NULL);
1429 set_threadObj(NULL);
1430 _anchor.clear();
1431 set_entry_point(NULL);
1432 set_jni_functions(jni_functions());
1433 set_callee_target(NULL);
1434 set_vm_result(NULL);
1435 set_vm_result_2(NULL);
1436 set_vframe_array_head(NULL);
1437 set_vframe_array_last(NULL);
1438 set_deferred_locals(NULL);
1439 set_deopt_mark(NULL);
1440 set_deopt_nmethod(NULL);
1441 clear_must_deopt_id();
1442 set_monitor_chunks(NULL);
1443 set_next(NULL);
1444 set_thread_state(_thread_new);
1445 _terminated = _not_terminated;
1446 _privileged_stack_top = NULL;
1447 _array_for_gc = NULL;
1448 _suspend_equivalent = false;
1449 _in_deopt_handler = 0;
1450 _doing_unsafe_access = false;
1451 _stack_guard_state = stack_guard_unused;
1452 (void)const_cast<oop&>(_exception_oop = NULL);
1453 _exception_pc = 0;
1454 _exception_handler_pc = 0;
1455 _is_method_handle_return = 0;
1456 _jvmti_thread_state= NULL;
1457 _should_post_on_exceptions_flag = JNI_FALSE;
1458 _jvmti_get_loaded_classes_closure = NULL;
1459 _interp_only_mode = 0;
1460 _special_runtime_exit_condition = _no_async_condition;
1461 _pending_async_exception = NULL;
1462 _thread_stat = NULL;
1463 _thread_stat = new ThreadStatistics();
1464 _blocked_on_compilation = false;
1465 _jni_active_critical = 0;
1466 _do_not_unlock_if_synchronized = false;
1467 _cached_monitor_info = NULL;
1468 _parker = Parker::Allocate(this) ;
1469
1470 #ifndef PRODUCT
1471 _jmp_ring_index = 0;
1472 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1473 record_jump(NULL, NULL, NULL, 0);
1474 }
1475 #endif /* PRODUCT */
1476
1477 set_thread_profiler(NULL);
1478 if (FlatProfiler::is_active()) {
1479 // This is where we would decide to either give each thread it's own profiler
1480 // or use one global one from FlatProfiler,
1481 // or up to some count of the number of profiled threads, etc.
1482 ThreadProfiler* pp = new ThreadProfiler();
1483 pp->engage();
1484 set_thread_profiler(pp);
1485 }
1486
1487 // Setup safepoint state info for this thread
1488 ThreadSafepointState::create(this);
1489
1490 debug_only(_java_call_counter = 0);
1491
1492 // JVMTI PopFrame support
1493 _popframe_condition = popframe_inactive;
1494 _popframe_preserved_args = NULL;
1495 _popframe_preserved_args_size = 0;
1496
1497 pd_initialize();
1498 }
1499
1500 #if INCLUDE_ALL_GCS
1501 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1502 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1503 #endif // INCLUDE_ALL_GCS
1504
1505 JavaThread::JavaThread(bool is_attaching_via_jni) :
1506 Thread()
1507 #if INCLUDE_ALL_GCS
1508 , _satb_mark_queue(&_satb_mark_queue_set),
1509 _dirty_card_queue(&_dirty_card_queue_set)
1510 #endif // INCLUDE_ALL_GCS
1511 {
1512 initialize();
1513 if (is_attaching_via_jni) {
1514 _jni_attach_state = _attaching_via_jni;
1515 } else {
1516 _jni_attach_state = _not_attaching_via_jni;
1517 }
1518 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1519 }
1520
1521 bool JavaThread::reguard_stack(address cur_sp) {
1522 if (_stack_guard_state != stack_guard_yellow_disabled) {
1523 return true; // Stack already guarded or guard pages not needed.
1524 }
1525
1526 if (register_stack_overflow()) {
1527 // For those architectures which have separate register and
1528 // memory stacks, we must check the register stack to see if
1529 // it has overflowed.
1530 return false;
1531 }
1532
1533 // Java code never executes within the yellow zone: the latter is only
1534 // there to provoke an exception during stack banging. If java code
1535 // is executing there, either StackShadowPages should be larger, or
1536 // some exception code in c1, c2 or the interpreter isn't unwinding
1537 // when it should.
1538 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1539
1540 enable_stack_yellow_zone();
1541 return true;
1542 }
1543
1544 bool JavaThread::reguard_stack(void) {
1545 return reguard_stack(os::current_stack_pointer());
1546 }
1547
1548
1549 void JavaThread::block_if_vm_exited() {
1550 if (_terminated == _vm_exited) {
1551 // _vm_exited is set at safepoint, and Threads_lock is never released
1552 // we will block here forever
1553 Threads_lock->lock_without_safepoint_check();
1554 ShouldNotReachHere();
1555 }
1556 }
1557
1558
1559 // Remove this ifdef when C1 is ported to the compiler interface.
1560 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1561
1562 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1563 Thread()
1564 #if INCLUDE_ALL_GCS
1565 , _satb_mark_queue(&_satb_mark_queue_set),
1566 _dirty_card_queue(&_dirty_card_queue_set)
1567 #endif // INCLUDE_ALL_GCS
1568 {
1569 if (TraceThreadEvents) {
1570 tty->print_cr("creating thread %p", this);
1571 }
1572 initialize();
1573 _jni_attach_state = _not_attaching_via_jni;
1574 set_entry_point(entry_point);
1575 // Create the native thread itself.
1576 // %note runtime_23
1577 os::ThreadType thr_type = os::java_thread;
1578 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1579 os::java_thread;
1580 os::create_thread(this, thr_type, stack_sz);
1581 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1582 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1583 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1584 // the exception consists of creating the exception object & initializing it, initialization
1585 // will leave the VM via a JavaCall and then all locks must be unlocked).
1586 //
1587 // The thread is still suspended when we reach here. Thread must be explicit started
1588 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1589 // by calling Threads:add. The reason why this is not done here, is because the thread
1590 // object must be fully initialized (take a look at JVM_Start)
1591 }
1592
1593 JavaThread::~JavaThread() {
1594 if (TraceThreadEvents) {
1595 tty->print_cr("terminate thread %p", this);
1596 }
1597
1598 // JSR166 -- return the parker to the free list
1599 Parker::Release(_parker);
1600 _parker = NULL ;
1601
1602 // Free any remaining previous UnrollBlock
1603 vframeArray* old_array = vframe_array_last();
1604
1605 if (old_array != NULL) {
1606 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1607 old_array->set_unroll_block(NULL);
1608 delete old_info;
1609 delete old_array;
1610 }
1611
1612 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1613 if (deferred != NULL) {
1614 // This can only happen if thread is destroyed before deoptimization occurs.
1615 assert(deferred->length() != 0, "empty array!");
1616 do {
1617 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1618 deferred->remove_at(0);
1619 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1620 delete dlv;
1621 } while (deferred->length() != 0);
1622 delete deferred;
1623 }
1624
1625 // All Java related clean up happens in exit
1626 ThreadSafepointState::destroy(this);
1627 if (_thread_profiler != NULL) delete _thread_profiler;
1628 if (_thread_stat != NULL) delete _thread_stat;
1629 }
1630
1631
1632 // The first routine called by a new Java thread
1633 void JavaThread::run() {
1634 // initialize thread-local alloc buffer related fields
1635 this->initialize_tlab();
1636
1637 // used to test validitity of stack trace backs
1638 this->record_base_of_stack_pointer();
1639
1640 // Record real stack base and size.
1641 this->record_stack_base_and_size();
1642
1643 // Initialize thread local storage; set before calling MutexLocker
1644 this->initialize_thread_local_storage();
1645
1646 this->create_stack_guard_pages();
1647
1648 this->cache_global_variables();
1649
1650 // Thread is now sufficient initialized to be handled by the safepoint code as being
1651 // in the VM. Change thread state from _thread_new to _thread_in_vm
1652 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1653
1654 assert(JavaThread::current() == this, "sanity check");
1655 assert(!Thread::current()->owns_locks(), "sanity check");
1656
1657 DTRACE_THREAD_PROBE(start, this);
1658
1659 // This operation might block. We call that after all safepoint checks for a new thread has
1660 // been completed.
1661 this->set_active_handles(JNIHandleBlock::allocate_block());
1662
1663 if (JvmtiExport::should_post_thread_life()) {
1664 JvmtiExport::post_thread_start(this);
1665 }
1666
1667 EventThreadStart event;
1668 if (event.should_commit()) {
1669 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1670 event.commit();
1671 }
1672
1673 // We call another function to do the rest so we are sure that the stack addresses used
1674 // from there will be lower than the stack base just computed
1675 thread_main_inner();
1676
1677 // Note, thread is no longer valid at this point!
1678 }
1679
1680
1681 void JavaThread::thread_main_inner() {
1682 assert(JavaThread::current() == this, "sanity check");
1683 assert(this->threadObj() != NULL, "just checking");
1684
1685 // Execute thread entry point unless this thread has a pending exception
1686 // or has been stopped before starting.
1687 // Note: Due to JVM_StopThread we can have pending exceptions already!
1688 if (!this->has_pending_exception() &&
1689 !java_lang_Thread::is_stillborn(this->threadObj())) {
1690 {
1691 ResourceMark rm(this);
1692 this->set_native_thread_name(this->get_thread_name());
1693 }
1694 HandleMark hm(this);
1695 this->entry_point()(this, this);
1696 }
1697
1698 DTRACE_THREAD_PROBE(stop, this);
1699
1700 this->exit(false);
1701 delete this;
1702 }
1703
1704
1705 static void ensure_join(JavaThread* thread) {
1706 // We do not need to grap the Threads_lock, since we are operating on ourself.
1707 Handle threadObj(thread, thread->threadObj());
1708 assert(threadObj.not_null(), "java thread object must exist");
1709 ObjectLocker lock(threadObj, thread);
1710 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1711 thread->clear_pending_exception();
1712 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1713 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1714 // Clear the native thread instance - this makes isAlive return false and allows the join()
1715 // to complete once we've done the notify_all below
1716 java_lang_Thread::set_thread(threadObj(), NULL);
1717 lock.notify_all(thread);
1718 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1719 thread->clear_pending_exception();
1720 }
1721
1722
1723 // For any new cleanup additions, please check to see if they need to be applied to
1724 // cleanup_failed_attach_current_thread as well.
1725 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1726 assert(this == JavaThread::current(), "thread consistency check");
1727
1728 HandleMark hm(this);
1729 Handle uncaught_exception(this, this->pending_exception());
1730 this->clear_pending_exception();
1731 Handle threadObj(this, this->threadObj());
1732 assert(threadObj.not_null(), "Java thread object should be created");
1733
1734 if (get_thread_profiler() != NULL) {
1735 get_thread_profiler()->disengage();
1736 ResourceMark rm;
1737 get_thread_profiler()->print(get_thread_name());
1738 }
1739
1740
1741 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1742 {
1743 EXCEPTION_MARK;
1744
1745 CLEAR_PENDING_EXCEPTION;
1746 }
1747 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1748 // has to be fixed by a runtime query method
1749 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1750 // JSR-166: change call from from ThreadGroup.uncaughtException to
1751 // java.lang.Thread.dispatchUncaughtException
1752 if (uncaught_exception.not_null()) {
1753 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1754 {
1755 EXCEPTION_MARK;
1756 // Check if the method Thread.dispatchUncaughtException() exists. If so
1757 // call it. Otherwise we have an older library without the JSR-166 changes,
1758 // so call ThreadGroup.uncaughtException()
1759 KlassHandle recvrKlass(THREAD, threadObj->klass());
1760 CallInfo callinfo;
1761 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1762 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1763 vmSymbols::dispatchUncaughtException_name(),
1764 vmSymbols::throwable_void_signature(),
1765 KlassHandle(), false, false, THREAD);
1766 CLEAR_PENDING_EXCEPTION;
1767 methodHandle method = callinfo.selected_method();
1768 if (method.not_null()) {
1769 JavaValue result(T_VOID);
1770 JavaCalls::call_virtual(&result,
1771 threadObj, thread_klass,
1772 vmSymbols::dispatchUncaughtException_name(),
1773 vmSymbols::throwable_void_signature(),
1774 uncaught_exception,
1775 THREAD);
1776 } else {
1777 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1778 JavaValue result(T_VOID);
1779 JavaCalls::call_virtual(&result,
1780 group, thread_group,
1781 vmSymbols::uncaughtException_name(),
1782 vmSymbols::thread_throwable_void_signature(),
1783 threadObj, // Arg 1
1784 uncaught_exception, // Arg 2
1785 THREAD);
1786 }
1787 if (HAS_PENDING_EXCEPTION) {
1788 ResourceMark rm(this);
1789 jio_fprintf(defaultStream::error_stream(),
1790 "\nException: %s thrown from the UncaughtExceptionHandler"
1791 " in thread \"%s\"\n",
1792 pending_exception()->klass()->external_name(),
1793 get_thread_name());
1794 CLEAR_PENDING_EXCEPTION;
1795 }
1796 }
1797 }
1798
1799 // Called before the java thread exit since we want to read info
1800 // from java_lang_Thread object
1801 EventThreadEnd event;
1802 if (event.should_commit()) {
1803 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1804 event.commit();
1805 }
1806
1807 // Call after last event on thread
1808 EVENT_THREAD_EXIT(this);
1809
1810 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1811 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1812 // is deprecated anyhow.
1813 if (!is_Compiler_thread()) {
1814 int count = 3;
1815 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1816 EXCEPTION_MARK;
1817 JavaValue result(T_VOID);
1818 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1819 JavaCalls::call_virtual(&result,
1820 threadObj, thread_klass,
1821 vmSymbols::exit_method_name(),
1822 vmSymbols::void_method_signature(),
1823 THREAD);
1824 CLEAR_PENDING_EXCEPTION;
1825 }
1826 }
1827 // notify JVMTI
1828 if (JvmtiExport::should_post_thread_life()) {
1829 JvmtiExport::post_thread_end(this);
1830 }
1831
1832 // We have notified the agents that we are exiting, before we go on,
1833 // we must check for a pending external suspend request and honor it
1834 // in order to not surprise the thread that made the suspend request.
1835 while (true) {
1836 {
1837 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1838 if (!is_external_suspend()) {
1839 set_terminated(_thread_exiting);
1840 ThreadService::current_thread_exiting(this);
1841 break;
1842 }
1843 // Implied else:
1844 // Things get a little tricky here. We have a pending external
1845 // suspend request, but we are holding the SR_lock so we
1846 // can't just self-suspend. So we temporarily drop the lock
1847 // and then self-suspend.
1848 }
1849
1850 ThreadBlockInVM tbivm(this);
1851 java_suspend_self();
1852
1853 // We're done with this suspend request, but we have to loop around
1854 // and check again. Eventually we will get SR_lock without a pending
1855 // external suspend request and will be able to mark ourselves as
1856 // exiting.
1857 }
1858 // no more external suspends are allowed at this point
1859 } else {
1860 // before_exit() has already posted JVMTI THREAD_END events
1861 }
1862
1863 // Notify waiters on thread object. This has to be done after exit() is called
1864 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1865 // group should have the destroyed bit set before waiters are notified).
1866 ensure_join(this);
1867 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1868
1869 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1870 // held by this thread must be released. A detach operation must only
1871 // get here if there are no Java frames on the stack. Therefore, any
1872 // owned monitors at this point MUST be JNI-acquired monitors which are
1873 // pre-inflated and in the monitor cache.
1874 //
1875 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1876 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1877 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1878 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1879 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1880 }
1881
1882 // These things needs to be done while we are still a Java Thread. Make sure that thread
1883 // is in a consistent state, in case GC happens
1884 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1885
1886 if (active_handles() != NULL) {
1887 JNIHandleBlock* block = active_handles();
1888 set_active_handles(NULL);
1889 JNIHandleBlock::release_block(block);
1890 }
1891
1892 if (free_handle_block() != NULL) {
1893 JNIHandleBlock* block = free_handle_block();
1894 set_free_handle_block(NULL);
1895 JNIHandleBlock::release_block(block);
1896 }
1897
1898 // These have to be removed while this is still a valid thread.
1899 remove_stack_guard_pages();
1900
1901 if (UseTLAB) {
1902 tlab().make_parsable(true); // retire TLAB
1903 }
1904
1905 if (JvmtiEnv::environments_might_exist()) {
1906 JvmtiExport::cleanup_thread(this);
1907 }
1908
1909 // We must flush any deferred card marks before removing a thread from
1910 // the list of active threads.
1911 Universe::heap()->flush_deferred_store_barrier(this);
1912 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1913
1914 #if INCLUDE_ALL_GCS
1915 // We must flush the G1-related buffers before removing a thread
1916 // from the list of active threads. We must do this after any deferred
1917 // card marks have been flushed (above) so that any entries that are
1918 // added to the thread's dirty card queue as a result are not lost.
1919 if (UseG1GC) {
1920 flush_barrier_queues();
1921 }
1922 #endif // INCLUDE_ALL_GCS
1923
1924 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1925 Threads::remove(this);
1926 }
1927
1928 #if INCLUDE_ALL_GCS
1929 // Flush G1-related queues.
1930 void JavaThread::flush_barrier_queues() {
1931 satb_mark_queue().flush();
1932 dirty_card_queue().flush();
1933 }
1934
1935 void JavaThread::initialize_queues() {
1936 assert(!SafepointSynchronize::is_at_safepoint(),
1937 "we should not be at a safepoint");
1938
1939 ObjPtrQueue& satb_queue = satb_mark_queue();
1940 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1941 // The SATB queue should have been constructed with its active
1942 // field set to false.
1943 assert(!satb_queue.is_active(), "SATB queue should not be active");
1944 assert(satb_queue.is_empty(), "SATB queue should be empty");
1945 // If we are creating the thread during a marking cycle, we should
1946 // set the active field of the SATB queue to true.
1947 if (satb_queue_set.is_active()) {
1948 satb_queue.set_active(true);
1949 }
1950
1951 DirtyCardQueue& dirty_queue = dirty_card_queue();
1952 // The dirty card queue should have been constructed with its
1953 // active field set to true.
1954 assert(dirty_queue.is_active(), "dirty card queue should be active");
1955 }
1956 #endif // INCLUDE_ALL_GCS
1957
1958 void JavaThread::cleanup_failed_attach_current_thread() {
1959 if (get_thread_profiler() != NULL) {
1960 get_thread_profiler()->disengage();
1961 ResourceMark rm;
1962 get_thread_profiler()->print(get_thread_name());
1963 }
1964
1965 if (active_handles() != NULL) {
1966 JNIHandleBlock* block = active_handles();
1967 set_active_handles(NULL);
1968 JNIHandleBlock::release_block(block);
1969 }
1970
1971 if (free_handle_block() != NULL) {
1972 JNIHandleBlock* block = free_handle_block();
1973 set_free_handle_block(NULL);
1974 JNIHandleBlock::release_block(block);
1975 }
1976
1977 // These have to be removed while this is still a valid thread.
1978 remove_stack_guard_pages();
1979
1980 if (UseTLAB) {
1981 tlab().make_parsable(true); // retire TLAB, if any
1982 }
1983
1984 #if INCLUDE_ALL_GCS
1985 if (UseG1GC) {
1986 flush_barrier_queues();
1987 }
1988 #endif // INCLUDE_ALL_GCS
1989
1990 Threads::remove(this);
1991 delete this;
1992 }
1993
1994
1995
1996
1997 JavaThread* JavaThread::active() {
1998 Thread* thread = ThreadLocalStorage::thread();
1999 assert(thread != NULL, "just checking");
2000 if (thread->is_Java_thread()) {
2001 return (JavaThread*) thread;
2002 } else {
2003 assert(thread->is_VM_thread(), "this must be a vm thread");
2004 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2005 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2006 assert(ret->is_Java_thread(), "must be a Java thread");
2007 return ret;
2008 }
2009 }
2010
2011 bool JavaThread::is_lock_owned(address adr) const {
2012 if (Thread::is_lock_owned(adr)) return true;
2013
2014 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2015 if (chunk->contains(adr)) return true;
2016 }
2017
2018 return false;
2019 }
2020
2021
2022 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2023 chunk->set_next(monitor_chunks());
2024 set_monitor_chunks(chunk);
2025 }
2026
2027 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2028 guarantee(monitor_chunks() != NULL, "must be non empty");
2029 if (monitor_chunks() == chunk) {
2030 set_monitor_chunks(chunk->next());
2031 } else {
2032 MonitorChunk* prev = monitor_chunks();
2033 while (prev->next() != chunk) prev = prev->next();
2034 prev->set_next(chunk->next());
2035 }
2036 }
2037
2038 // JVM support.
2039
2040 // Note: this function shouldn't block if it's called in
2041 // _thread_in_native_trans state (such as from
2042 // check_special_condition_for_native_trans()).
2043 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2044
2045 if (has_last_Java_frame() && has_async_condition()) {
2046 // If we are at a polling page safepoint (not a poll return)
2047 // then we must defer async exception because live registers
2048 // will be clobbered by the exception path. Poll return is
2049 // ok because the call we a returning from already collides
2050 // with exception handling registers and so there is no issue.
2051 // (The exception handling path kills call result registers but
2052 // this is ok since the exception kills the result anyway).
2053
2054 if (is_at_poll_safepoint()) {
2055 // if the code we are returning to has deoptimized we must defer
2056 // the exception otherwise live registers get clobbered on the
2057 // exception path before deoptimization is able to retrieve them.
2058 //
2059 RegisterMap map(this, false);
2060 frame caller_fr = last_frame().sender(&map);
2061 assert(caller_fr.is_compiled_frame(), "what?");
2062 if (caller_fr.is_deoptimized_frame()) {
2063 if (TraceExceptions) {
2064 ResourceMark rm;
2065 tty->print_cr("deferred async exception at compiled safepoint");
2066 }
2067 return;
2068 }
2069 }
2070 }
2071
2072 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2073 if (condition == _no_async_condition) {
2074 // Conditions have changed since has_special_runtime_exit_condition()
2075 // was called:
2076 // - if we were here only because of an external suspend request,
2077 // then that was taken care of above (or cancelled) so we are done
2078 // - if we were here because of another async request, then it has
2079 // been cleared between the has_special_runtime_exit_condition()
2080 // and now so again we are done
2081 return;
2082 }
2083
2084 // Check for pending async. exception
2085 if (_pending_async_exception != NULL) {
2086 // Only overwrite an already pending exception, if it is not a threadDeath.
2087 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2088
2089 // We cannot call Exceptions::_throw(...) here because we cannot block
2090 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2091
2092 if (TraceExceptions) {
2093 ResourceMark rm;
2094 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2095 if (has_last_Java_frame() ) {
2096 frame f = last_frame();
2097 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2098 }
2099 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2100 }
2101 _pending_async_exception = NULL;
2102 clear_has_async_exception();
2103 }
2104 }
2105
2106 if (check_unsafe_error &&
2107 condition == _async_unsafe_access_error && !has_pending_exception()) {
2108 condition = _no_async_condition; // done
2109 switch (thread_state()) {
2110 case _thread_in_vm:
2111 {
2112 JavaThread* THREAD = this;
2113 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2114 }
2115 case _thread_in_native:
2116 {
2117 ThreadInVMfromNative tiv(this);
2118 JavaThread* THREAD = this;
2119 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2120 }
2121 case _thread_in_Java:
2122 {
2123 ThreadInVMfromJava tiv(this);
2124 JavaThread* THREAD = this;
2125 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2126 }
2127 default:
2128 ShouldNotReachHere();
2129 }
2130 }
2131
2132 assert(condition == _no_async_condition || has_pending_exception() ||
2133 (!check_unsafe_error && condition == _async_unsafe_access_error),
2134 "must have handled the async condition, if no exception");
2135 }
2136
2137 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2138 //
2139 // Check for pending external suspend. Internal suspend requests do
2140 // not use handle_special_runtime_exit_condition().
2141 // If JNIEnv proxies are allowed, don't self-suspend if the target
2142 // thread is not the current thread. In older versions of jdbx, jdbx
2143 // threads could call into the VM with another thread's JNIEnv so we
2144 // can be here operating on behalf of a suspended thread (4432884).
2145 bool do_self_suspend = is_external_suspend_with_lock();
2146 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2147 //
2148 // Because thread is external suspended the safepoint code will count
2149 // thread as at a safepoint. This can be odd because we can be here
2150 // as _thread_in_Java which would normally transition to _thread_blocked
2151 // at a safepoint. We would like to mark the thread as _thread_blocked
2152 // before calling java_suspend_self like all other callers of it but
2153 // we must then observe proper safepoint protocol. (We can't leave
2154 // _thread_blocked with a safepoint in progress). However we can be
2155 // here as _thread_in_native_trans so we can't use a normal transition
2156 // constructor/destructor pair because they assert on that type of
2157 // transition. We could do something like:
2158 //
2159 // JavaThreadState state = thread_state();
2160 // set_thread_state(_thread_in_vm);
2161 // {
2162 // ThreadBlockInVM tbivm(this);
2163 // java_suspend_self()
2164 // }
2165 // set_thread_state(_thread_in_vm_trans);
2166 // if (safepoint) block;
2167 // set_thread_state(state);
2168 //
2169 // but that is pretty messy. Instead we just go with the way the
2170 // code has worked before and note that this is the only path to
2171 // java_suspend_self that doesn't put the thread in _thread_blocked
2172 // mode.
2173
2174 frame_anchor()->make_walkable(this);
2175 java_suspend_self();
2176
2177 // We might be here for reasons in addition to the self-suspend request
2178 // so check for other async requests.
2179 }
2180
2181 if (check_asyncs) {
2182 check_and_handle_async_exceptions();
2183 }
2184 }
2185
2186 void JavaThread::send_thread_stop(oop java_throwable) {
2187 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2188 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2189 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2190
2191 // Do not throw asynchronous exceptions against the compiler thread
2192 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2193 if (is_Compiler_thread()) return;
2194
2195 {
2196 // Actually throw the Throwable against the target Thread - however
2197 // only if there is no thread death exception installed already.
2198 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2199 // If the topmost frame is a runtime stub, then we are calling into
2200 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2201 // must deoptimize the caller before continuing, as the compiled exception handler table
2202 // may not be valid
2203 if (has_last_Java_frame()) {
2204 frame f = last_frame();
2205 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2206 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2207 RegisterMap reg_map(this, UseBiasedLocking);
2208 frame compiled_frame = f.sender(®_map);
2209 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2210 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2211 }
2212 }
2213 }
2214
2215 // Set async. pending exception in thread.
2216 set_pending_async_exception(java_throwable);
2217
2218 if (TraceExceptions) {
2219 ResourceMark rm;
2220 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2221 }
2222 // for AbortVMOnException flag
2223 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2224 }
2225 }
2226
2227
2228 // Interrupt thread so it will wake up from a potential wait()
2229 Thread::interrupt(this);
2230 }
2231
2232 // External suspension mechanism.
2233 //
2234 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2235 // to any VM_locks and it is at a transition
2236 // Self-suspension will happen on the transition out of the vm.
2237 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2238 //
2239 // Guarantees on return:
2240 // + Target thread will not execute any new bytecode (that's why we need to
2241 // force a safepoint)
2242 // + Target thread will not enter any new monitors
2243 //
2244 void JavaThread::java_suspend() {
2245 { MutexLocker mu(Threads_lock);
2246 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2247 return;
2248 }
2249 }
2250
2251 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2252 if (!is_external_suspend()) {
2253 // a racing resume has cancelled us; bail out now
2254 return;
2255 }
2256
2257 // suspend is done
2258 uint32_t debug_bits = 0;
2259 // Warning: is_ext_suspend_completed() may temporarily drop the
2260 // SR_lock to allow the thread to reach a stable thread state if
2261 // it is currently in a transient thread state.
2262 if (is_ext_suspend_completed(false /* !called_by_wait */,
2263 SuspendRetryDelay, &debug_bits) ) {
2264 return;
2265 }
2266 }
2267
2268 VM_ForceSafepoint vm_suspend;
2269 VMThread::execute(&vm_suspend);
2270 }
2271
2272 // Part II of external suspension.
2273 // A JavaThread self suspends when it detects a pending external suspend
2274 // request. This is usually on transitions. It is also done in places
2275 // where continuing to the next transition would surprise the caller,
2276 // e.g., monitor entry.
2277 //
2278 // Returns the number of times that the thread self-suspended.
2279 //
2280 // Note: DO NOT call java_suspend_self() when you just want to block current
2281 // thread. java_suspend_self() is the second stage of cooperative
2282 // suspension for external suspend requests and should only be used
2283 // to complete an external suspend request.
2284 //
2285 int JavaThread::java_suspend_self() {
2286 int ret = 0;
2287
2288 // we are in the process of exiting so don't suspend
2289 if (is_exiting()) {
2290 clear_external_suspend();
2291 return ret;
2292 }
2293
2294 assert(_anchor.walkable() ||
2295 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2296 "must have walkable stack");
2297
2298 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2299
2300 assert(!this->is_ext_suspended(),
2301 "a thread trying to self-suspend should not already be suspended");
2302
2303 if (this->is_suspend_equivalent()) {
2304 // If we are self-suspending as a result of the lifting of a
2305 // suspend equivalent condition, then the suspend_equivalent
2306 // flag is not cleared until we set the ext_suspended flag so
2307 // that wait_for_ext_suspend_completion() returns consistent
2308 // results.
2309 this->clear_suspend_equivalent();
2310 }
2311
2312 // A racing resume may have cancelled us before we grabbed SR_lock
2313 // above. Or another external suspend request could be waiting for us
2314 // by the time we return from SR_lock()->wait(). The thread
2315 // that requested the suspension may already be trying to walk our
2316 // stack and if we return now, we can change the stack out from under
2317 // it. This would be a "bad thing (TM)" and cause the stack walker
2318 // to crash. We stay self-suspended until there are no more pending
2319 // external suspend requests.
2320 while (is_external_suspend()) {
2321 ret++;
2322 this->set_ext_suspended();
2323
2324 // _ext_suspended flag is cleared by java_resume()
2325 while (is_ext_suspended()) {
2326 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2327 }
2328 }
2329
2330 return ret;
2331 }
2332
2333 #ifdef ASSERT
2334 // verify the JavaThread has not yet been published in the Threads::list, and
2335 // hence doesn't need protection from concurrent access at this stage
2336 void JavaThread::verify_not_published() {
2337 if (!Threads_lock->owned_by_self()) {
2338 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2339 assert( !Threads::includes(this),
2340 "java thread shouldn't have been published yet!");
2341 }
2342 else {
2343 assert( !Threads::includes(this),
2344 "java thread shouldn't have been published yet!");
2345 }
2346 }
2347 #endif
2348
2349 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2350 // progress or when _suspend_flags is non-zero.
2351 // Current thread needs to self-suspend if there is a suspend request and/or
2352 // block if a safepoint is in progress.
2353 // Async exception ISN'T checked.
2354 // Note only the ThreadInVMfromNative transition can call this function
2355 // directly and when thread state is _thread_in_native_trans
2356 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2357 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2358
2359 JavaThread *curJT = JavaThread::current();
2360 bool do_self_suspend = thread->is_external_suspend();
2361
2362 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2363
2364 // If JNIEnv proxies are allowed, don't self-suspend if the target
2365 // thread is not the current thread. In older versions of jdbx, jdbx
2366 // threads could call into the VM with another thread's JNIEnv so we
2367 // can be here operating on behalf of a suspended thread (4432884).
2368 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2369 JavaThreadState state = thread->thread_state();
2370
2371 // We mark this thread_blocked state as a suspend-equivalent so
2372 // that a caller to is_ext_suspend_completed() won't be confused.
2373 // The suspend-equivalent state is cleared by java_suspend_self().
2374 thread->set_suspend_equivalent();
2375
2376 // If the safepoint code sees the _thread_in_native_trans state, it will
2377 // wait until the thread changes to other thread state. There is no
2378 // guarantee on how soon we can obtain the SR_lock and complete the
2379 // self-suspend request. It would be a bad idea to let safepoint wait for
2380 // too long. Temporarily change the state to _thread_blocked to
2381 // let the VM thread know that this thread is ready for GC. The problem
2382 // of changing thread state is that safepoint could happen just after
2383 // java_suspend_self() returns after being resumed, and VM thread will
2384 // see the _thread_blocked state. We must check for safepoint
2385 // after restoring the state and make sure we won't leave while a safepoint
2386 // is in progress.
2387 thread->set_thread_state(_thread_blocked);
2388 thread->java_suspend_self();
2389 thread->set_thread_state(state);
2390 // Make sure new state is seen by VM thread
2391 if (os::is_MP()) {
2392 if (UseMembar) {
2393 // Force a fence between the write above and read below
2394 OrderAccess::fence();
2395 } else {
2396 // Must use this rather than serialization page in particular on Windows
2397 InterfaceSupport::serialize_memory(thread);
2398 }
2399 }
2400 }
2401
2402 if (SafepointSynchronize::do_call_back()) {
2403 // If we are safepointing, then block the caller which may not be
2404 // the same as the target thread (see above).
2405 SafepointSynchronize::block(curJT);
2406 }
2407
2408 if (thread->is_deopt_suspend()) {
2409 thread->clear_deopt_suspend();
2410 RegisterMap map(thread, false);
2411 frame f = thread->last_frame();
2412 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2413 f = f.sender(&map);
2414 }
2415 if (f.id() == thread->must_deopt_id()) {
2416 thread->clear_must_deopt_id();
2417 f.deoptimize(thread);
2418 } else {
2419 fatal("missed deoptimization!");
2420 }
2421 }
2422 }
2423
2424 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2425 // progress or when _suspend_flags is non-zero.
2426 // Current thread needs to self-suspend if there is a suspend request and/or
2427 // block if a safepoint is in progress.
2428 // Also check for pending async exception (not including unsafe access error).
2429 // Note only the native==>VM/Java barriers can call this function and when
2430 // thread state is _thread_in_native_trans.
2431 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2432 check_safepoint_and_suspend_for_native_trans(thread);
2433
2434 if (thread->has_async_exception()) {
2435 // We are in _thread_in_native_trans state, don't handle unsafe
2436 // access error since that may block.
2437 thread->check_and_handle_async_exceptions(false);
2438 }
2439 }
2440
2441 // This is a variant of the normal
2442 // check_special_condition_for_native_trans with slightly different
2443 // semantics for use by critical native wrappers. It does all the
2444 // normal checks but also performs the transition back into
2445 // thread_in_Java state. This is required so that critical natives
2446 // can potentially block and perform a GC if they are the last thread
2447 // exiting the GC_locker.
2448 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2449 check_special_condition_for_native_trans(thread);
2450
2451 // Finish the transition
2452 thread->set_thread_state(_thread_in_Java);
2453
2454 if (thread->do_critical_native_unlock()) {
2455 ThreadInVMfromJavaNoAsyncException tiv(thread);
2456 GC_locker::unlock_critical(thread);
2457 thread->clear_critical_native_unlock();
2458 }
2459 }
2460
2461 // We need to guarantee the Threads_lock here, since resumes are not
2462 // allowed during safepoint synchronization
2463 // Can only resume from an external suspension
2464 void JavaThread::java_resume() {
2465 assert_locked_or_safepoint(Threads_lock);
2466
2467 // Sanity check: thread is gone, has started exiting or the thread
2468 // was not externally suspended.
2469 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2470 return;
2471 }
2472
2473 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2474
2475 clear_external_suspend();
2476
2477 if (is_ext_suspended()) {
2478 clear_ext_suspended();
2479 SR_lock()->notify_all();
2480 }
2481 }
2482
2483 void JavaThread::create_stack_guard_pages() {
2484 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2485 address low_addr = stack_base() - stack_size();
2486 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2487
2488 int allocate = os::allocate_stack_guard_pages();
2489 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2490
2491 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2492 warning("Attempt to allocate stack guard pages failed.");
2493 return;
2494 }
2495
2496 if (os::guard_memory((char *) low_addr, len)) {
2497 _stack_guard_state = stack_guard_enabled;
2498 } else {
2499 warning("Attempt to protect stack guard pages failed.");
2500 if (os::uncommit_memory((char *) low_addr, len)) {
2501 warning("Attempt to deallocate stack guard pages failed.");
2502 }
2503 }
2504 }
2505
2506 void JavaThread::remove_stack_guard_pages() {
2507 assert(Thread::current() == this, "from different thread");
2508 if (_stack_guard_state == stack_guard_unused) return;
2509 address low_addr = stack_base() - stack_size();
2510 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2511
2512 if (os::allocate_stack_guard_pages()) {
2513 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2514 _stack_guard_state = stack_guard_unused;
2515 } else {
2516 warning("Attempt to deallocate stack guard pages failed.");
2517 }
2518 } else {
2519 if (_stack_guard_state == stack_guard_unused) return;
2520 if (os::unguard_memory((char *) low_addr, len)) {
2521 _stack_guard_state = stack_guard_unused;
2522 } else {
2523 warning("Attempt to unprotect stack guard pages failed.");
2524 }
2525 }
2526 }
2527
2528 void JavaThread::enable_stack_yellow_zone() {
2529 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2530 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2531
2532 // The base notation is from the stacks point of view, growing downward.
2533 // We need to adjust it to work correctly with guard_memory()
2534 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2535
2536 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2537 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2538
2539 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2540 _stack_guard_state = stack_guard_enabled;
2541 } else {
2542 warning("Attempt to guard stack yellow zone failed.");
2543 }
2544 enable_register_stack_guard();
2545 }
2546
2547 void JavaThread::disable_stack_yellow_zone() {
2548 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2549 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2550
2551 // Simply return if called for a thread that does not use guard pages.
2552 if (_stack_guard_state == stack_guard_unused) return;
2553
2554 // The base notation is from the stacks point of view, growing downward.
2555 // We need to adjust it to work correctly with guard_memory()
2556 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2557
2558 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2559 _stack_guard_state = stack_guard_yellow_disabled;
2560 } else {
2561 warning("Attempt to unguard stack yellow zone failed.");
2562 }
2563 disable_register_stack_guard();
2564 }
2565
2566 void JavaThread::enable_stack_red_zone() {
2567 // The base notation is from the stacks point of view, growing downward.
2568 // We need to adjust it to work correctly with guard_memory()
2569 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2570 address base = stack_red_zone_base() - stack_red_zone_size();
2571
2572 guarantee(base < stack_base(),"Error calculating stack red zone");
2573 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2574
2575 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2576 warning("Attempt to guard stack red zone failed.");
2577 }
2578 }
2579
2580 void JavaThread::disable_stack_red_zone() {
2581 // The base notation is from the stacks point of view, growing downward.
2582 // We need to adjust it to work correctly with guard_memory()
2583 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2584 address base = stack_red_zone_base() - stack_red_zone_size();
2585 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2586 warning("Attempt to unguard stack red zone failed.");
2587 }
2588 }
2589
2590 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2591 // ignore is there is no stack
2592 if (!has_last_Java_frame()) return;
2593 // traverse the stack frames. Starts from top frame.
2594 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2595 frame* fr = fst.current();
2596 f(fr, fst.register_map());
2597 }
2598 }
2599
2600
2601 #ifndef PRODUCT
2602 // Deoptimization
2603 // Function for testing deoptimization
2604 void JavaThread::deoptimize() {
2605 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2606 StackFrameStream fst(this, UseBiasedLocking);
2607 bool deopt = false; // Dump stack only if a deopt actually happens.
2608 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2609 // Iterate over all frames in the thread and deoptimize
2610 for(; !fst.is_done(); fst.next()) {
2611 if(fst.current()->can_be_deoptimized()) {
2612
2613 if (only_at) {
2614 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2615 // consists of comma or carriage return separated numbers so
2616 // search for the current bci in that string.
2617 address pc = fst.current()->pc();
2618 nmethod* nm = (nmethod*) fst.current()->cb();
2619 ScopeDesc* sd = nm->scope_desc_at( pc);
2620 char buffer[8];
2621 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2622 size_t len = strlen(buffer);
2623 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2624 while (found != NULL) {
2625 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2626 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2627 // Check that the bci found is bracketed by terminators.
2628 break;
2629 }
2630 found = strstr(found + 1, buffer);
2631 }
2632 if (!found) {
2633 continue;
2634 }
2635 }
2636
2637 if (DebugDeoptimization && !deopt) {
2638 deopt = true; // One-time only print before deopt
2639 tty->print_cr("[BEFORE Deoptimization]");
2640 trace_frames();
2641 trace_stack();
2642 }
2643 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2644 }
2645 }
2646
2647 if (DebugDeoptimization && deopt) {
2648 tty->print_cr("[AFTER Deoptimization]");
2649 trace_frames();
2650 }
2651 }
2652
2653
2654 // Make zombies
2655 void JavaThread::make_zombies() {
2656 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2657 if (fst.current()->can_be_deoptimized()) {
2658 // it is a Java nmethod
2659 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2660 nm->make_not_entrant();
2661 }
2662 }
2663 }
2664 #endif // PRODUCT
2665
2666
2667 void JavaThread::deoptimized_wrt_marked_nmethods() {
2668 if (!has_last_Java_frame()) return;
2669 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2670 StackFrameStream fst(this, UseBiasedLocking);
2671 for(; !fst.is_done(); fst.next()) {
2672 if (fst.current()->should_be_deoptimized()) {
2673 if (LogCompilation && xtty != NULL) {
2674 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2675 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2676 this->name(), nm != NULL ? nm->compile_id() : -1);
2677 }
2678
2679 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2680 }
2681 }
2682 }
2683
2684
2685 // GC support
2686 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2687
2688 void JavaThread::gc_epilogue() {
2689 frames_do(frame_gc_epilogue);
2690 }
2691
2692
2693 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2694
2695 void JavaThread::gc_prologue() {
2696 frames_do(frame_gc_prologue);
2697 }
2698
2699 // If the caller is a NamedThread, then remember, in the current scope,
2700 // the given JavaThread in its _processed_thread field.
2701 class RememberProcessedThread: public StackObj {
2702 NamedThread* _cur_thr;
2703 public:
2704 RememberProcessedThread(JavaThread* jthr) {
2705 Thread* thread = Thread::current();
2706 if (thread->is_Named_thread()) {
2707 _cur_thr = (NamedThread *)thread;
2708 _cur_thr->set_processed_thread(jthr);
2709 } else {
2710 _cur_thr = NULL;
2711 }
2712 }
2713
2714 ~RememberProcessedThread() {
2715 if (_cur_thr) {
2716 _cur_thr->set_processed_thread(NULL);
2717 }
2718 }
2719 };
2720
2721 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2722 // Verify that the deferred card marks have been flushed.
2723 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2724
2725 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2726 // since there may be more than one thread using each ThreadProfiler.
2727
2728 // Traverse the GCHandles
2729 Thread::oops_do(f, cld_f, cf);
2730
2731 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2732 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2733
2734 if (has_last_Java_frame()) {
2735 // Record JavaThread to GC thread
2736 RememberProcessedThread rpt(this);
2737
2738 // Traverse the privileged stack
2739 if (_privileged_stack_top != NULL) {
2740 _privileged_stack_top->oops_do(f);
2741 }
2742
2743 // traverse the registered growable array
2744 if (_array_for_gc != NULL) {
2745 for (int index = 0; index < _array_for_gc->length(); index++) {
2746 f->do_oop(_array_for_gc->adr_at(index));
2747 }
2748 }
2749
2750 // Traverse the monitor chunks
2751 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2752 chunk->oops_do(f);
2753 }
2754
2755 // Traverse the execution stack
2756 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2757 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2758 }
2759 }
2760
2761 // callee_target is never live across a gc point so NULL it here should
2762 // it still contain a methdOop.
2763
2764 set_callee_target(NULL);
2765
2766 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2767 // If we have deferred set_locals there might be oops waiting to be
2768 // written
2769 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2770 if (list != NULL) {
2771 for (int i = 0; i < list->length(); i++) {
2772 list->at(i)->oops_do(f);
2773 }
2774 }
2775
2776 // Traverse instance variables at the end since the GC may be moving things
2777 // around using this function
2778 f->do_oop((oop*) &_threadObj);
2779 f->do_oop((oop*) &_vm_result);
2780 f->do_oop((oop*) &_exception_oop);
2781 f->do_oop((oop*) &_pending_async_exception);
2782
2783 if (jvmti_thread_state() != NULL) {
2784 jvmti_thread_state()->oops_do(f);
2785 }
2786 }
2787
2788 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2789 Thread::nmethods_do(cf); // (super method is a no-op)
2790
2791 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2792 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2793
2794 if (has_last_Java_frame()) {
2795 // Traverse the execution stack
2796 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2797 fst.current()->nmethods_do(cf);
2798 }
2799 }
2800 }
2801
2802 void JavaThread::metadata_do(void f(Metadata*)) {
2803 Thread::metadata_do(f);
2804 if (has_last_Java_frame()) {
2805 // Traverse the execution stack to call f() on the methods in the stack
2806 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2807 fst.current()->metadata_do(f);
2808 }
2809 } else if (is_Compiler_thread()) {
2810 // need to walk ciMetadata in current compile tasks to keep alive.
2811 CompilerThread* ct = (CompilerThread*)this;
2812 if (ct->env() != NULL) {
2813 ct->env()->metadata_do(f);
2814 }
2815 }
2816 }
2817
2818 // Printing
2819 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2820 switch (_thread_state) {
2821 case _thread_uninitialized: return "_thread_uninitialized";
2822 case _thread_new: return "_thread_new";
2823 case _thread_new_trans: return "_thread_new_trans";
2824 case _thread_in_native: return "_thread_in_native";
2825 case _thread_in_native_trans: return "_thread_in_native_trans";
2826 case _thread_in_vm: return "_thread_in_vm";
2827 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2828 case _thread_in_Java: return "_thread_in_Java";
2829 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2830 case _thread_blocked: return "_thread_blocked";
2831 case _thread_blocked_trans: return "_thread_blocked_trans";
2832 default: return "unknown thread state";
2833 }
2834 }
2835
2836 #ifndef PRODUCT
2837 void JavaThread::print_thread_state_on(outputStream *st) const {
2838 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2839 };
2840 void JavaThread::print_thread_state() const {
2841 print_thread_state_on(tty);
2842 };
2843 #endif // PRODUCT
2844
2845 // Called by Threads::print() for VM_PrintThreads operation
2846 void JavaThread::print_on(outputStream *st) const {
2847 st->print("\"%s\" ", get_thread_name());
2848 oop thread_oop = threadObj();
2849 if (thread_oop != NULL) {
2850 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2851 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2852 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2853 }
2854 Thread::print_on(st);
2855 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2856 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2857 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2858 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2859 }
2860 #ifndef PRODUCT
2861 print_thread_state_on(st);
2862 _safepoint_state->print_on(st);
2863 #endif // PRODUCT
2864 }
2865
2866 // Called by fatal error handler. The difference between this and
2867 // JavaThread::print() is that we can't grab lock or allocate memory.
2868 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2869 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2870 oop thread_obj = threadObj();
2871 if (thread_obj != NULL) {
2872 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2873 }
2874 st->print(" [");
2875 st->print("%s", _get_thread_state_name(_thread_state));
2876 if (osthread()) {
2877 st->print(", id=%d", osthread()->thread_id());
2878 }
2879 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2880 _stack_base - _stack_size, _stack_base);
2881 st->print("]");
2882 return;
2883 }
2884
2885 // Verification
2886
2887 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2888
2889 void JavaThread::verify() {
2890 // Verify oops in the thread.
2891 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2892
2893 // Verify the stack frames.
2894 frames_do(frame_verify);
2895 }
2896
2897 // CR 6300358 (sub-CR 2137150)
2898 // Most callers of this method assume that it can't return NULL but a
2899 // thread may not have a name whilst it is in the process of attaching to
2900 // the VM - see CR 6412693, and there are places where a JavaThread can be
2901 // seen prior to having it's threadObj set (eg JNI attaching threads and
2902 // if vm exit occurs during initialization). These cases can all be accounted
2903 // for such that this method never returns NULL.
2904 const char* JavaThread::get_thread_name() const {
2905 #ifdef ASSERT
2906 // early safepoints can hit while current thread does not yet have TLS
2907 if (!SafepointSynchronize::is_at_safepoint()) {
2908 Thread *cur = Thread::current();
2909 if (!(cur->is_Java_thread() && cur == this)) {
2910 // Current JavaThreads are allowed to get their own name without
2911 // the Threads_lock.
2912 assert_locked_or_safepoint(Threads_lock);
2913 }
2914 }
2915 #endif // ASSERT
2916 return get_thread_name_string();
2917 }
2918
2919 // Returns a non-NULL representation of this thread's name, or a suitable
2920 // descriptive string if there is no set name
2921 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2922 const char* name_str;
2923 oop thread_obj = threadObj();
2924 if (thread_obj != NULL) {
2925 typeArrayOop name = java_lang_Thread::name(thread_obj);
2926 if (name != NULL) {
2927 if (buf == NULL) {
2928 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2929 }
2930 else {
2931 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2932 }
2933 }
2934 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2935 name_str = "<no-name - thread is attaching>";
2936 }
2937 else {
2938 name_str = Thread::name();
2939 }
2940 }
2941 else {
2942 name_str = Thread::name();
2943 }
2944 assert(name_str != NULL, "unexpected NULL thread name");
2945 return name_str;
2946 }
2947
2948
2949 const char* JavaThread::get_threadgroup_name() const {
2950 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2951 oop thread_obj = threadObj();
2952 if (thread_obj != NULL) {
2953 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2954 if (thread_group != NULL) {
2955 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2956 // ThreadGroup.name can be null
2957 if (name != NULL) {
2958 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2959 return str;
2960 }
2961 }
2962 }
2963 return NULL;
2964 }
2965
2966 const char* JavaThread::get_parent_name() const {
2967 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2968 oop thread_obj = threadObj();
2969 if (thread_obj != NULL) {
2970 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2971 if (thread_group != NULL) {
2972 oop parent = java_lang_ThreadGroup::parent(thread_group);
2973 if (parent != NULL) {
2974 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2975 // ThreadGroup.name can be null
2976 if (name != NULL) {
2977 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2978 return str;
2979 }
2980 }
2981 }
2982 }
2983 return NULL;
2984 }
2985
2986 ThreadPriority JavaThread::java_priority() const {
2987 oop thr_oop = threadObj();
2988 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2989 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2990 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2991 return priority;
2992 }
2993
2994 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2995
2996 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2997 // Link Java Thread object <-> C++ Thread
2998
2999 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3000 // and put it into a new Handle. The Handle "thread_oop" can then
3001 // be used to pass the C++ thread object to other methods.
3002
3003 // Set the Java level thread object (jthread) field of the
3004 // new thread (a JavaThread *) to C++ thread object using the
3005 // "thread_oop" handle.
3006
3007 // Set the thread field (a JavaThread *) of the
3008 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3009
3010 Handle thread_oop(Thread::current(),
3011 JNIHandles::resolve_non_null(jni_thread));
3012 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3013 "must be initialized");
3014 set_threadObj(thread_oop());
3015 java_lang_Thread::set_thread(thread_oop(), this);
3016
3017 if (prio == NoPriority) {
3018 prio = java_lang_Thread::priority(thread_oop());
3019 assert(prio != NoPriority, "A valid priority should be present");
3020 }
3021
3022 // Push the Java priority down to the native thread; needs Threads_lock
3023 Thread::set_priority(this, prio);
3024
3025 prepare_ext();
3026
3027 // Add the new thread to the Threads list and set it in motion.
3028 // We must have threads lock in order to call Threads::add.
3029 // It is crucial that we do not block before the thread is
3030 // added to the Threads list for if a GC happens, then the java_thread oop
3031 // will not be visited by GC.
3032 Threads::add(this);
3033 }
3034
3035 oop JavaThread::current_park_blocker() {
3036 // Support for JSR-166 locks
3037 oop thread_oop = threadObj();
3038 if (thread_oop != NULL &&
3039 JDK_Version::current().supports_thread_park_blocker()) {
3040 return java_lang_Thread::park_blocker(thread_oop);
3041 }
3042 return NULL;
3043 }
3044
3045
3046 void JavaThread::print_stack_on(outputStream* st) {
3047 if (!has_last_Java_frame()) return;
3048 ResourceMark rm;
3049 HandleMark hm;
3050
3051 RegisterMap reg_map(this);
3052 vframe* start_vf = last_java_vframe(®_map);
3053 int count = 0;
3054 for (vframe* f = start_vf; f; f = f->sender() ) {
3055 if (f->is_java_frame()) {
3056 javaVFrame* jvf = javaVFrame::cast(f);
3057 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3058
3059 // Print out lock information
3060 if (JavaMonitorsInStackTrace) {
3061 jvf->print_lock_info_on(st, count);
3062 }
3063 } else {
3064 // Ignore non-Java frames
3065 }
3066
3067 // Bail-out case for too deep stacks
3068 count++;
3069 if (MaxJavaStackTraceDepth == count) return;
3070 }
3071 }
3072
3073
3074 // JVMTI PopFrame support
3075 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3076 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3077 if (in_bytes(size_in_bytes) != 0) {
3078 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3079 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3080 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3081 }
3082 }
3083
3084 void* JavaThread::popframe_preserved_args() {
3085 return _popframe_preserved_args;
3086 }
3087
3088 ByteSize JavaThread::popframe_preserved_args_size() {
3089 return in_ByteSize(_popframe_preserved_args_size);
3090 }
3091
3092 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3093 int sz = in_bytes(popframe_preserved_args_size());
3094 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3095 return in_WordSize(sz / wordSize);
3096 }
3097
3098 void JavaThread::popframe_free_preserved_args() {
3099 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3100 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3101 _popframe_preserved_args = NULL;
3102 _popframe_preserved_args_size = 0;
3103 }
3104
3105 #ifndef PRODUCT
3106
3107 void JavaThread::trace_frames() {
3108 tty->print_cr("[Describe stack]");
3109 int frame_no = 1;
3110 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3111 tty->print(" %d. ", frame_no++);
3112 fst.current()->print_value_on(tty,this);
3113 tty->cr();
3114 }
3115 }
3116
3117 class PrintAndVerifyOopClosure: public OopClosure {
3118 protected:
3119 template <class T> inline void do_oop_work(T* p) {
3120 oop obj = oopDesc::load_decode_heap_oop(p);
3121 if (obj == NULL) return;
3122 tty->print(INTPTR_FORMAT ": ", p);
3123 if (obj->is_oop_or_null()) {
3124 if (obj->is_objArray()) {
3125 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3126 } else {
3127 obj->print();
3128 }
3129 } else {
3130 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3131 }
3132 tty->cr();
3133 }
3134 public:
3135 virtual void do_oop(oop* p) { do_oop_work(p); }
3136 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3137 };
3138
3139
3140 static void oops_print(frame* f, const RegisterMap *map) {
3141 PrintAndVerifyOopClosure print;
3142 f->print_value();
3143 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3144 }
3145
3146 // Print our all the locations that contain oops and whether they are
3147 // valid or not. This useful when trying to find the oldest frame
3148 // where an oop has gone bad since the frame walk is from youngest to
3149 // oldest.
3150 void JavaThread::trace_oops() {
3151 tty->print_cr("[Trace oops]");
3152 frames_do(oops_print);
3153 }
3154
3155
3156 #ifdef ASSERT
3157 // Print or validate the layout of stack frames
3158 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3159 ResourceMark rm;
3160 PRESERVE_EXCEPTION_MARK;
3161 FrameValues values;
3162 int frame_no = 0;
3163 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3164 fst.current()->describe(values, ++frame_no);
3165 if (depth == frame_no) break;
3166 }
3167 if (validate_only) {
3168 values.validate();
3169 } else {
3170 tty->print_cr("[Describe stack layout]");
3171 values.print(this);
3172 }
3173 }
3174 #endif
3175
3176 void JavaThread::trace_stack_from(vframe* start_vf) {
3177 ResourceMark rm;
3178 int vframe_no = 1;
3179 for (vframe* f = start_vf; f; f = f->sender() ) {
3180 if (f->is_java_frame()) {
3181 javaVFrame::cast(f)->print_activation(vframe_no++);
3182 } else {
3183 f->print();
3184 }
3185 if (vframe_no > StackPrintLimit) {
3186 tty->print_cr("...<more frames>...");
3187 return;
3188 }
3189 }
3190 }
3191
3192
3193 void JavaThread::trace_stack() {
3194 if (!has_last_Java_frame()) return;
3195 ResourceMark rm;
3196 HandleMark hm;
3197 RegisterMap reg_map(this);
3198 trace_stack_from(last_java_vframe(®_map));
3199 }
3200
3201
3202 #endif // PRODUCT
3203
3204
3205 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3206 assert(reg_map != NULL, "a map must be given");
3207 frame f = last_frame();
3208 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3209 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3210 }
3211 return NULL;
3212 }
3213
3214
3215 Klass* JavaThread::security_get_caller_class(int depth) {
3216 vframeStream vfst(this);
3217 vfst.security_get_caller_frame(depth);
3218 if (!vfst.at_end()) {
3219 return vfst.method()->method_holder();
3220 }
3221 return NULL;
3222 }
3223
3224 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3225 assert(thread->is_Compiler_thread(), "must be compiler thread");
3226 CompileBroker::compiler_thread_loop();
3227 }
3228
3229 // Create a CompilerThread
3230 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3231 : JavaThread(&compiler_thread_entry) {
3232 _env = NULL;
3233 _log = NULL;
3234 _task = NULL;
3235 _queue = queue;
3236 _counters = counters;
3237 _buffer_blob = NULL;
3238 _scanned_nmethod = NULL;
3239 _compiler = NULL;
3240
3241 #ifndef PRODUCT
3242 _ideal_graph_printer = NULL;
3243 #endif
3244 }
3245
3246 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3247 JavaThread::oops_do(f, cld_f, cf);
3248 if (_scanned_nmethod != NULL && cf != NULL) {
3249 // Safepoints can occur when the sweeper is scanning an nmethod so
3250 // process it here to make sure it isn't unloaded in the middle of
3251 // a scan.
3252 cf->do_code_blob(_scanned_nmethod);
3253 }
3254 }
3255
3256
3257 // ======= Threads ========
3258
3259 // The Threads class links together all active threads, and provides
3260 // operations over all threads. It is protected by its own Mutex
3261 // lock, which is also used in other contexts to protect thread
3262 // operations from having the thread being operated on from exiting
3263 // and going away unexpectedly (e.g., safepoint synchronization)
3264
3265 JavaThread* Threads::_thread_list = NULL;
3266 int Threads::_number_of_threads = 0;
3267 int Threads::_number_of_non_daemon_threads = 0;
3268 int Threads::_return_code = 0;
3269 size_t JavaThread::_stack_size_at_create = 0;
3270 #ifdef ASSERT
3271 bool Threads::_vm_complete = false;
3272 #endif
3273
3274 // All JavaThreads
3275 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3276
3277 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3278 void Threads::threads_do(ThreadClosure* tc) {
3279 assert_locked_or_safepoint(Threads_lock);
3280 // ALL_JAVA_THREADS iterates through all JavaThreads
3281 ALL_JAVA_THREADS(p) {
3282 tc->do_thread(p);
3283 }
3284 // Someday we could have a table or list of all non-JavaThreads.
3285 // For now, just manually iterate through them.
3286 tc->do_thread(VMThread::vm_thread());
3287 Universe::heap()->gc_threads_do(tc);
3288 WatcherThread *wt = WatcherThread::watcher_thread();
3289 // Strictly speaking, the following NULL check isn't sufficient to make sure
3290 // the data for WatcherThread is still valid upon being examined. However,
3291 // considering that WatchThread terminates when the VM is on the way to
3292 // exit at safepoint, the chance of the above is extremely small. The right
3293 // way to prevent termination of WatcherThread would be to acquire
3294 // Terminator_lock, but we can't do that without violating the lock rank
3295 // checking in some cases.
3296 if (wt != NULL)
3297 tc->do_thread(wt);
3298
3299 // If CompilerThreads ever become non-JavaThreads, add them here
3300 }
3301
3302 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3303
3304 extern void JDK_Version_init();
3305
3306 // Check version
3307 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3308
3309 // Initialize the output stream module
3310 ostream_init();
3311
3312 // Process java launcher properties.
3313 Arguments::process_sun_java_launcher_properties(args);
3314
3315 // Initialize the os module before using TLS
3316 os::init();
3317
3318 // Initialize system properties.
3319 Arguments::init_system_properties();
3320
3321 // So that JDK version can be used as a discrimintor when parsing arguments
3322 JDK_Version_init();
3323
3324 // Update/Initialize System properties after JDK version number is known
3325 Arguments::init_version_specific_system_properties();
3326
3327 // Parse arguments
3328 jint parse_result = Arguments::parse(args);
3329 if (parse_result != JNI_OK) return parse_result;
3330
3331 os::init_before_ergo();
3332
3333 jint ergo_result = Arguments::apply_ergo();
3334 if (ergo_result != JNI_OK) return ergo_result;
3335
3336 if (PauseAtStartup) {
3337 os::pause();
3338 }
3339
3340 #ifndef USDT2
3341 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3342 #else /* USDT2 */
3343 HOTSPOT_VM_INIT_BEGIN();
3344 #endif /* USDT2 */
3345
3346 // Record VM creation timing statistics
3347 TraceVmCreationTime create_vm_timer;
3348 create_vm_timer.start();
3349
3350 // Timing (must come after argument parsing)
3351 TraceTime timer("Create VM", TraceStartupTime);
3352
3353 // Initialize the os module after parsing the args
3354 jint os_init_2_result = os::init_2();
3355 if (os_init_2_result != JNI_OK) return os_init_2_result;
3356
3357 jint adjust_after_os_result = Arguments::adjust_after_os();
3358 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3359
3360 // intialize TLS
3361 ThreadLocalStorage::init();
3362
3363 // Initialize output stream logging
3364 ostream_init_log();
3365
3366 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3367 // Must be before create_vm_init_agents()
3368 if (Arguments::init_libraries_at_startup()) {
3369 convert_vm_init_libraries_to_agents();
3370 }
3371
3372 // Launch -agentlib/-agentpath and converted -Xrun agents
3373 if (Arguments::init_agents_at_startup()) {
3374 create_vm_init_agents();
3375 }
3376
3377 // Initialize Threads state
3378 _thread_list = NULL;
3379 _number_of_threads = 0;
3380 _number_of_non_daemon_threads = 0;
3381
3382 // Initialize global data structures and create system classes in heap
3383 vm_init_globals();
3384
3385 // Attach the main thread to this os thread
3386 JavaThread* main_thread = new JavaThread();
3387 main_thread->set_thread_state(_thread_in_vm);
3388 // must do this before set_active_handles and initialize_thread_local_storage
3389 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3390 // change the stack size recorded here to one based on the java thread
3391 // stacksize. This adjusted size is what is used to figure the placement
3392 // of the guard pages.
3393 main_thread->record_stack_base_and_size();
3394 main_thread->initialize_thread_local_storage();
3395
3396 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3397
3398 if (!main_thread->set_as_starting_thread()) {
3399 vm_shutdown_during_initialization(
3400 "Failed necessary internal allocation. Out of swap space");
3401 delete main_thread;
3402 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3403 return JNI_ENOMEM;
3404 }
3405
3406 // Enable guard page *after* os::create_main_thread(), otherwise it would
3407 // crash Linux VM, see notes in os_linux.cpp.
3408 main_thread->create_stack_guard_pages();
3409
3410 // Initialize Java-Level synchronization subsystem
3411 ObjectMonitor::Initialize() ;
3412
3413 // Initialize global modules
3414 jint status = init_globals();
3415 if (status != JNI_OK) {
3416 delete main_thread;
3417 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3418 return status;
3419 }
3420
3421 // Should be done after the heap is fully created
3422 main_thread->cache_global_variables();
3423
3424 HandleMark hm;
3425
3426 { MutexLocker mu(Threads_lock);
3427 Threads::add(main_thread);
3428 }
3429
3430 // Any JVMTI raw monitors entered in onload will transition into
3431 // real raw monitor. VM is setup enough here for raw monitor enter.
3432 JvmtiExport::transition_pending_onload_raw_monitors();
3433
3434 // Create the VMThread
3435 { TraceTime timer("Start VMThread", TraceStartupTime);
3436 VMThread::create();
3437 Thread* vmthread = VMThread::vm_thread();
3438
3439 if (!os::create_thread(vmthread, os::vm_thread))
3440 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3441
3442 // Wait for the VM thread to become ready, and VMThread::run to initialize
3443 // Monitors can have spurious returns, must always check another state flag
3444 {
3445 MutexLocker ml(Notify_lock);
3446 os::start_thread(vmthread);
3447 while (vmthread->active_handles() == NULL) {
3448 Notify_lock->wait();
3449 }
3450 }
3451 }
3452
3453 assert (Universe::is_fully_initialized(), "not initialized");
3454 if (VerifyDuringStartup) {
3455 // Make sure we're starting with a clean slate.
3456 VM_Verify verify_op;
3457 VMThread::execute(&verify_op);
3458 }
3459
3460 EXCEPTION_MARK;
3461
3462 // At this point, the Universe is initialized, but we have not executed
3463 // any byte code. Now is a good time (the only time) to dump out the
3464 // internal state of the JVM for sharing.
3465 if (DumpSharedSpaces) {
3466 MetaspaceShared::preload_and_dump(CHECK_0);
3467 ShouldNotReachHere();
3468 }
3469
3470 // Always call even when there are not JVMTI environments yet, since environments
3471 // may be attached late and JVMTI must track phases of VM execution
3472 JvmtiExport::enter_start_phase();
3473
3474 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3475 JvmtiExport::post_vm_start();
3476
3477 {
3478 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3479
3480 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3481 create_vm_init_libraries();
3482 }
3483
3484 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3485
3486 // Initialize java_lang.System (needed before creating the thread)
3487 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3488 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3489 Handle thread_group = create_initial_thread_group(CHECK_0);
3490 Universe::set_main_thread_group(thread_group());
3491 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3492 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3493 main_thread->set_threadObj(thread_object);
3494 // Set thread status to running since main thread has
3495 // been started and running.
3496 java_lang_Thread::set_thread_status(thread_object,
3497 java_lang_Thread::RUNNABLE);
3498
3499 // The VM creates & returns objects of this class. Make sure it's initialized.
3500 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3501
3502 // The VM preresolves methods to these classes. Make sure that they get initialized
3503 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3504 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3505 call_initializeSystemClass(CHECK_0);
3506
3507 // get the Java runtime name after java.lang.System is initialized
3508 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3509 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3510
3511 // an instance of OutOfMemory exception has been allocated earlier
3512 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3513 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3514 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3515 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3516 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3517 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3518 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3519 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3520 }
3521
3522 // See : bugid 4211085.
3523 // Background : the static initializer of java.lang.Compiler tries to read
3524 // property"java.compiler" and read & write property "java.vm.info".
3525 // When a security manager is installed through the command line
3526 // option "-Djava.security.manager", the above properties are not
3527 // readable and the static initializer for java.lang.Compiler fails
3528 // resulting in a NoClassDefFoundError. This can happen in any
3529 // user code which calls methods in java.lang.Compiler.
3530 // Hack : the hack is to pre-load and initialize this class, so that only
3531 // system domains are on the stack when the properties are read.
3532 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3533 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3534 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3535 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3536 // Once that is done, we should remove this hack.
3537 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3538
3539 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3540 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3541 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3542 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3543 // This should also be taken out as soon as 4211383 gets fixed.
3544 reset_vm_info_property(CHECK_0);
3545
3546 quicken_jni_functions();
3547
3548 // Must be run after init_ft which initializes ft_enabled
3549 if (TRACE_INITIALIZE() != JNI_OK) {
3550 vm_exit_during_initialization("Failed to initialize tracing backend");
3551 }
3552
3553 // Set flag that basic initialization has completed. Used by exceptions and various
3554 // debug stuff, that does not work until all basic classes have been initialized.
3555 set_init_completed();
3556
3557 Metaspace::post_initialize();
3558
3559 #ifndef USDT2
3560 HS_DTRACE_PROBE(hotspot, vm__init__end);
3561 #else /* USDT2 */
3562 HOTSPOT_VM_INIT_END();
3563 #endif /* USDT2 */
3564
3565 // record VM initialization completion time
3566 #if INCLUDE_MANAGEMENT
3567 Management::record_vm_init_completed();
3568 #endif // INCLUDE_MANAGEMENT
3569
3570 // Compute system loader. Note that this has to occur after set_init_completed, since
3571 // valid exceptions may be thrown in the process.
3572 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3573 // set_init_completed has just been called, causing exceptions not to be shortcut
3574 // anymore. We call vm_exit_during_initialization directly instead.
3575 SystemDictionary::compute_java_system_loader(THREAD);
3576 if (HAS_PENDING_EXCEPTION) {
3577 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3578 }
3579
3580 #if INCLUDE_ALL_GCS
3581 // Support for ConcurrentMarkSweep. This should be cleaned up
3582 // and better encapsulated. The ugly nested if test would go away
3583 // once things are properly refactored. XXX YSR
3584 if (UseConcMarkSweepGC || UseG1GC) {
3585 if (UseConcMarkSweepGC) {
3586 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3587 } else {
3588 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3589 }
3590 if (HAS_PENDING_EXCEPTION) {
3591 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3592 }
3593 }
3594 #endif // INCLUDE_ALL_GCS
3595
3596 // Always call even when there are not JVMTI environments yet, since environments
3597 // may be attached late and JVMTI must track phases of VM execution
3598 JvmtiExport::enter_live_phase();
3599
3600 // Signal Dispatcher needs to be started before VMInit event is posted
3601 os::signal_init();
3602
3603 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3604 if (!DisableAttachMechanism) {
3605 AttachListener::vm_start();
3606 if (StartAttachListener || AttachListener::init_at_startup()) {
3607 AttachListener::init();
3608 }
3609 }
3610
3611 // Launch -Xrun agents
3612 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3613 // back-end can launch with -Xdebug -Xrunjdwp.
3614 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3615 create_vm_init_libraries();
3616 }
3617
3618 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3619 JvmtiExport::post_vm_initialized();
3620
3621 if (TRACE_START() != JNI_OK) {
3622 vm_exit_during_initialization("Failed to start tracing backend.");
3623 }
3624
3625 if (CleanChunkPoolAsync) {
3626 Chunk::start_chunk_pool_cleaner_task();
3627 }
3628
3629 // initialize compiler(s)
3630 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3631 CompileBroker::compilation_init();
3632 #endif
3633
3634 if (EnableInvokeDynamic) {
3635 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3636 // It is done after compilers are initialized, because otherwise compilations of
3637 // signature polymorphic MH intrinsics can be missed
3638 // (see SystemDictionary::find_method_handle_intrinsic).
3639 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3640 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3641 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3642 }
3643
3644 #if INCLUDE_MANAGEMENT
3645 Management::initialize(THREAD);
3646 #endif // INCLUDE_MANAGEMENT
3647
3648 if (HAS_PENDING_EXCEPTION) {
3649 // management agent fails to start possibly due to
3650 // configuration problem and is responsible for printing
3651 // stack trace if appropriate. Simply exit VM.
3652 vm_exit(1);
3653 }
3654
3655 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3656 if (MemProfiling) MemProfiler::engage();
3657 StatSampler::engage();
3658 if (CheckJNICalls) JniPeriodicChecker::engage();
3659
3660 BiasedLocking::init();
3661
3662 #if INCLUDE_RTM_OPT
3663 RTMLockingCounters::init();
3664 #endif
3665
3666 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3667 call_postVMInitHook(THREAD);
3668 // The Java side of PostVMInitHook.run must deal with all
3669 // exceptions and provide means of diagnosis.
3670 if (HAS_PENDING_EXCEPTION) {
3671 CLEAR_PENDING_EXCEPTION;
3672 }
3673 }
3674
3675 {
3676 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3677 // Make sure the watcher thread can be started by WatcherThread::start()
3678 // or by dynamic enrollment.
3679 WatcherThread::make_startable();
3680 // Start up the WatcherThread if there are any periodic tasks
3681 // NOTE: All PeriodicTasks should be registered by now. If they
3682 // aren't, late joiners might appear to start slowly (we might
3683 // take a while to process their first tick).
3684 if (PeriodicTask::num_tasks() > 0) {
3685 WatcherThread::start();
3686 }
3687 }
3688
3689 // Give os specific code one last chance to start
3690 os::init_3();
3691
3692 create_vm_timer.end();
3693 #ifdef ASSERT
3694 _vm_complete = true;
3695 #endif
3696 return JNI_OK;
3697 }
3698
3699 // type for the Agent_OnLoad and JVM_OnLoad entry points
3700 extern "C" {
3701 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3702 }
3703 // Find a command line agent library and return its entry point for
3704 // -agentlib: -agentpath: -Xrun
3705 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3706 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3707 OnLoadEntry_t on_load_entry = NULL;
3708 void *library = NULL;
3709
3710 if (!agent->valid()) {
3711 char buffer[JVM_MAXPATHLEN];
3712 char ebuf[1024];
3713 const char *name = agent->name();
3714 const char *msg = "Could not find agent library ";
3715
3716 // First check to see if agent is statically linked into executable
3717 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3718 library = agent->os_lib();
3719 } else if (agent->is_absolute_path()) {
3720 library = os::dll_load(name, ebuf, sizeof ebuf);
3721 if (library == NULL) {
3722 const char *sub_msg = " in absolute path, with error: ";
3723 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3724 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3725 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3726 // If we can't find the agent, exit.
3727 vm_exit_during_initialization(buf, NULL);
3728 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3729 }
3730 } else {
3731 // Try to load the agent from the standard dll directory
3732 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3733 name)) {
3734 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3735 }
3736 if (library == NULL) { // Try the local directory
3737 char ns[1] = {0};
3738 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3739 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3740 }
3741 if (library == NULL) {
3742 const char *sub_msg = " on the library path, with error: ";
3743 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3744 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3745 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3746 // If we can't find the agent, exit.
3747 vm_exit_during_initialization(buf, NULL);
3748 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3749 }
3750 }
3751 }
3752 agent->set_os_lib(library);
3753 agent->set_valid();
3754 }
3755
3756 // Find the OnLoad function.
3757 on_load_entry =
3758 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3759 false,
3760 on_load_symbols,
3761 num_symbol_entries));
3762 return on_load_entry;
3763 }
3764
3765 // Find the JVM_OnLoad entry point
3766 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3767 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3768 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3769 }
3770
3771 // Find the Agent_OnLoad entry point
3772 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3773 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3774 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3775 }
3776
3777 // For backwards compatibility with -Xrun
3778 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3779 // treated like -agentpath:
3780 // Must be called before agent libraries are created
3781 void Threads::convert_vm_init_libraries_to_agents() {
3782 AgentLibrary* agent;
3783 AgentLibrary* next;
3784
3785 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3786 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3787 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3788
3789 // If there is an JVM_OnLoad function it will get called later,
3790 // otherwise see if there is an Agent_OnLoad
3791 if (on_load_entry == NULL) {
3792 on_load_entry = lookup_agent_on_load(agent);
3793 if (on_load_entry != NULL) {
3794 // switch it to the agent list -- so that Agent_OnLoad will be called,
3795 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3796 Arguments::convert_library_to_agent(agent);
3797 } else {
3798 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3799 }
3800 }
3801 }
3802 }
3803
3804 // Create agents for -agentlib: -agentpath: and converted -Xrun
3805 // Invokes Agent_OnLoad
3806 // Called very early -- before JavaThreads exist
3807 void Threads::create_vm_init_agents() {
3808 extern struct JavaVM_ main_vm;
3809 AgentLibrary* agent;
3810
3811 JvmtiExport::enter_onload_phase();
3812
3813 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3814 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3815
3816 if (on_load_entry != NULL) {
3817 // Invoke the Agent_OnLoad function
3818 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3819 if (err != JNI_OK) {
3820 vm_exit_during_initialization("agent library failed to init", agent->name());
3821 }
3822 } else {
3823 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3824 }
3825 }
3826 JvmtiExport::enter_primordial_phase();
3827 }
3828
3829 extern "C" {
3830 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3831 }
3832
3833 void Threads::shutdown_vm_agents() {
3834 // Send any Agent_OnUnload notifications
3835 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3836 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3837 extern struct JavaVM_ main_vm;
3838 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3839
3840 // Find the Agent_OnUnload function.
3841 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3842 os::find_agent_function(agent,
3843 false,
3844 on_unload_symbols,
3845 num_symbol_entries));
3846
3847 // Invoke the Agent_OnUnload function
3848 if (unload_entry != NULL) {
3849 JavaThread* thread = JavaThread::current();
3850 ThreadToNativeFromVM ttn(thread);
3851 HandleMark hm(thread);
3852 (*unload_entry)(&main_vm);
3853 }
3854 }
3855 }
3856
3857 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3858 // Invokes JVM_OnLoad
3859 void Threads::create_vm_init_libraries() {
3860 extern struct JavaVM_ main_vm;
3861 AgentLibrary* agent;
3862
3863 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3864 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3865
3866 if (on_load_entry != NULL) {
3867 // Invoke the JVM_OnLoad function
3868 JavaThread* thread = JavaThread::current();
3869 ThreadToNativeFromVM ttn(thread);
3870 HandleMark hm(thread);
3871 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3872 if (err != JNI_OK) {
3873 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3874 }
3875 } else {
3876 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3877 }
3878 }
3879 }
3880
3881 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3882 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3883
3884 JavaThread* java_thread = NULL;
3885 // Sequential search for now. Need to do better optimization later.
3886 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3887 oop tobj = thread->threadObj();
3888 if (!thread->is_exiting() &&
3889 tobj != NULL &&
3890 java_tid == java_lang_Thread::thread_id(tobj)) {
3891 java_thread = thread;
3892 break;
3893 }
3894 }
3895 return java_thread;
3896 }
3897
3898
3899 // Last thread running calls java.lang.Shutdown.shutdown()
3900 void JavaThread::invoke_shutdown_hooks() {
3901 HandleMark hm(this);
3902
3903 // We could get here with a pending exception, if so clear it now.
3904 if (this->has_pending_exception()) {
3905 this->clear_pending_exception();
3906 }
3907
3908 EXCEPTION_MARK;
3909 Klass* k =
3910 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3911 THREAD);
3912 if (k != NULL) {
3913 // SystemDictionary::resolve_or_null will return null if there was
3914 // an exception. If we cannot load the Shutdown class, just don't
3915 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3916 // and finalizers (if runFinalizersOnExit is set) won't be run.
3917 // Note that if a shutdown hook was registered or runFinalizersOnExit
3918 // was called, the Shutdown class would have already been loaded
3919 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3920 instanceKlassHandle shutdown_klass (THREAD, k);
3921 JavaValue result(T_VOID);
3922 JavaCalls::call_static(&result,
3923 shutdown_klass,
3924 vmSymbols::shutdown_method_name(),
3925 vmSymbols::void_method_signature(),
3926 THREAD);
3927 }
3928 CLEAR_PENDING_EXCEPTION;
3929 }
3930
3931 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3932 // the program falls off the end of main(). Another VM exit path is through
3933 // vm_exit() when the program calls System.exit() to return a value or when
3934 // there is a serious error in VM. The two shutdown paths are not exactly
3935 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3936 // and VM_Exit op at VM level.
3937 //
3938 // Shutdown sequence:
3939 // + Shutdown native memory tracking if it is on
3940 // + Wait until we are the last non-daemon thread to execute
3941 // <-- every thing is still working at this moment -->
3942 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3943 // shutdown hooks, run finalizers if finalization-on-exit
3944 // + Call before_exit(), prepare for VM exit
3945 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3946 // currently the only user of this mechanism is File.deleteOnExit())
3947 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3948 // post thread end and vm death events to JVMTI,
3949 // stop signal thread
3950 // + Call JavaThread::exit(), it will:
3951 // > release JNI handle blocks, remove stack guard pages
3952 // > remove this thread from Threads list
3953 // <-- no more Java code from this thread after this point -->
3954 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3955 // the compiler threads at safepoint
3956 // <-- do not use anything that could get blocked by Safepoint -->
3957 // + Disable tracing at JNI/JVM barriers
3958 // + Set _vm_exited flag for threads that are still running native code
3959 // + Delete this thread
3960 // + Call exit_globals()
3961 // > deletes tty
3962 // > deletes PerfMemory resources
3963 // + Return to caller
3964
3965 bool Threads::destroy_vm() {
3966 JavaThread* thread = JavaThread::current();
3967
3968 #ifdef ASSERT
3969 _vm_complete = false;
3970 #endif
3971 // Wait until we are the last non-daemon thread to execute
3972 { MutexLocker nu(Threads_lock);
3973 while (Threads::number_of_non_daemon_threads() > 1 )
3974 // This wait should make safepoint checks, wait without a timeout,
3975 // and wait as a suspend-equivalent condition.
3976 //
3977 // Note: If the FlatProfiler is running and this thread is waiting
3978 // for another non-daemon thread to finish, then the FlatProfiler
3979 // is waiting for the external suspend request on this thread to
3980 // complete. wait_for_ext_suspend_completion() will eventually
3981 // timeout, but that takes time. Making this wait a suspend-
3982 // equivalent condition solves that timeout problem.
3983 //
3984 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3985 Mutex::_as_suspend_equivalent_flag);
3986 }
3987
3988 // Hang forever on exit if we are reporting an error.
3989 if (ShowMessageBoxOnError && is_error_reported()) {
3990 os::infinite_sleep();
3991 }
3992 os::wait_for_keypress_at_exit();
3993
3994 if (JDK_Version::is_jdk12x_version()) {
3995 // We are the last thread running, so check if finalizers should be run.
3996 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3997 HandleMark rm(thread);
3998 Universe::run_finalizers_on_exit();
3999 } else {
4000 // run Java level shutdown hooks
4001 thread->invoke_shutdown_hooks();
4002 }
4003
4004 before_exit(thread);
4005
4006 thread->exit(true);
4007
4008 // Stop VM thread.
4009 {
4010 // 4945125 The vm thread comes to a safepoint during exit.
4011 // GC vm_operations can get caught at the safepoint, and the
4012 // heap is unparseable if they are caught. Grab the Heap_lock
4013 // to prevent this. The GC vm_operations will not be able to
4014 // queue until after the vm thread is dead. After this point,
4015 // we'll never emerge out of the safepoint before the VM exits.
4016
4017 MutexLocker ml(Heap_lock);
4018
4019 VMThread::wait_for_vm_thread_exit();
4020 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4021 VMThread::destroy();
4022 }
4023
4024 // clean up ideal graph printers
4025 #if defined(COMPILER2) && !defined(PRODUCT)
4026 IdealGraphPrinter::clean_up();
4027 #endif
4028
4029 // Now, all Java threads are gone except daemon threads. Daemon threads
4030 // running Java code or in VM are stopped by the Safepoint. However,
4031 // daemon threads executing native code are still running. But they
4032 // will be stopped at native=>Java/VM barriers. Note that we can't
4033 // simply kill or suspend them, as it is inherently deadlock-prone.
4034
4035 #ifndef PRODUCT
4036 // disable function tracing at JNI/JVM barriers
4037 TraceJNICalls = false;
4038 TraceJVMCalls = false;
4039 TraceRuntimeCalls = false;
4040 #endif
4041
4042 VM_Exit::set_vm_exited();
4043
4044 notify_vm_shutdown();
4045
4046 delete thread;
4047
4048 // exit_globals() will delete tty
4049 exit_globals();
4050
4051 return true;
4052 }
4053
4054
4055 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4056 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4057 return is_supported_jni_version(version);
4058 }
4059
4060
4061 jboolean Threads::is_supported_jni_version(jint version) {
4062 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4063 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4064 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4065 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4066 return JNI_FALSE;
4067 }
4068
4069
4070 void Threads::add(JavaThread* p, bool force_daemon) {
4071 // The threads lock must be owned at this point
4072 assert_locked_or_safepoint(Threads_lock);
4073
4074 // See the comment for this method in thread.hpp for its purpose and
4075 // why it is called here.
4076 p->initialize_queues();
4077 p->set_next(_thread_list);
4078 _thread_list = p;
4079 _number_of_threads++;
4080 oop threadObj = p->threadObj();
4081 bool daemon = true;
4082 // Bootstrapping problem: threadObj can be null for initial
4083 // JavaThread (or for threads attached via JNI)
4084 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4085 _number_of_non_daemon_threads++;
4086 daemon = false;
4087 }
4088
4089 ThreadService::add_thread(p, daemon);
4090
4091 // Possible GC point.
4092 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4093 }
4094
4095 void Threads::remove(JavaThread* p) {
4096 // Extra scope needed for Thread_lock, so we can check
4097 // that we do not remove thread without safepoint code notice
4098 { MutexLocker ml(Threads_lock);
4099
4100 assert(includes(p), "p must be present");
4101
4102 JavaThread* current = _thread_list;
4103 JavaThread* prev = NULL;
4104
4105 while (current != p) {
4106 prev = current;
4107 current = current->next();
4108 }
4109
4110 if (prev) {
4111 prev->set_next(current->next());
4112 } else {
4113 _thread_list = p->next();
4114 }
4115 _number_of_threads--;
4116 oop threadObj = p->threadObj();
4117 bool daemon = true;
4118 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4119 _number_of_non_daemon_threads--;
4120 daemon = false;
4121
4122 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4123 // on destroy_vm will wake up.
4124 if (number_of_non_daemon_threads() == 1)
4125 Threads_lock->notify_all();
4126 }
4127 ThreadService::remove_thread(p, daemon);
4128
4129 // Make sure that safepoint code disregard this thread. This is needed since
4130 // the thread might mess around with locks after this point. This can cause it
4131 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4132 // of this thread since it is removed from the queue.
4133 p->set_terminated_value();
4134 } // unlock Threads_lock
4135
4136 // Since Events::log uses a lock, we grab it outside the Threads_lock
4137 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4138 }
4139
4140 // Threads_lock must be held when this is called (or must be called during a safepoint)
4141 bool Threads::includes(JavaThread* p) {
4142 assert(Threads_lock->is_locked(), "sanity check");
4143 ALL_JAVA_THREADS(q) {
4144 if (q == p ) {
4145 return true;
4146 }
4147 }
4148 return false;
4149 }
4150
4151 // Operations on the Threads list for GC. These are not explicitly locked,
4152 // but the garbage collector must provide a safe context for them to run.
4153 // In particular, these things should never be called when the Threads_lock
4154 // is held by some other thread. (Note: the Safepoint abstraction also
4155 // uses the Threads_lock to gurantee this property. It also makes sure that
4156 // all threads gets blocked when exiting or starting).
4157
4158 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4159 ALL_JAVA_THREADS(p) {
4160 p->oops_do(f, cld_f, cf);
4161 }
4162 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4163 }
4164
4165 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4166 // Introduce a mechanism allowing parallel threads to claim threads as
4167 // root groups. Overhead should be small enough to use all the time,
4168 // even in sequential code.
4169 SharedHeap* sh = SharedHeap::heap();
4170 // Cannot yet substitute active_workers for n_par_threads
4171 // because of G1CollectedHeap::verify() use of
4172 // SharedHeap::process_roots(). n_par_threads == 0 will
4173 // turn off parallelism in process_roots while active_workers
4174 // is being used for parallelism elsewhere.
4175 bool is_par = sh->n_par_threads() > 0;
4176 assert(!is_par ||
4177 (SharedHeap::heap()->n_par_threads() ==
4178 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4179 int cp = SharedHeap::heap()->strong_roots_parity();
4180 ALL_JAVA_THREADS(p) {
4181 if (p->claim_oops_do(is_par, cp)) {
4182 p->oops_do(f, cld_f, cf);
4183 }
4184 }
4185 VMThread* vmt = VMThread::vm_thread();
4186 if (vmt->claim_oops_do(is_par, cp)) {
4187 vmt->oops_do(f, cld_f, cf);
4188 }
4189 }
4190
4191 #if INCLUDE_ALL_GCS
4192 // Used by ParallelScavenge
4193 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4194 ALL_JAVA_THREADS(p) {
4195 q->enqueue(new ThreadRootsTask(p));
4196 }
4197 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4198 }
4199
4200 // Used by Parallel Old
4201 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4202 ALL_JAVA_THREADS(p) {
4203 q->enqueue(new ThreadRootsMarkingTask(p));
4204 }
4205 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4206 }
4207 #endif // INCLUDE_ALL_GCS
4208
4209 void Threads::nmethods_do(CodeBlobClosure* cf) {
4210 ALL_JAVA_THREADS(p) {
4211 p->nmethods_do(cf);
4212 }
4213 VMThread::vm_thread()->nmethods_do(cf);
4214 }
4215
4216 void Threads::metadata_do(void f(Metadata*)) {
4217 ALL_JAVA_THREADS(p) {
4218 p->metadata_do(f);
4219 }
4220 }
4221
4222 void Threads::gc_epilogue() {
4223 ALL_JAVA_THREADS(p) {
4224 p->gc_epilogue();
4225 }
4226 }
4227
4228 void Threads::gc_prologue() {
4229 ALL_JAVA_THREADS(p) {
4230 p->gc_prologue();
4231 }
4232 }
4233
4234 void Threads::deoptimized_wrt_marked_nmethods() {
4235 ALL_JAVA_THREADS(p) {
4236 p->deoptimized_wrt_marked_nmethods();
4237 }
4238 }
4239
4240
4241 // Get count Java threads that are waiting to enter the specified monitor.
4242 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4243 address monitor, bool doLock) {
4244 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4245 "must grab Threads_lock or be at safepoint");
4246 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4247
4248 int i = 0;
4249 {
4250 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4251 ALL_JAVA_THREADS(p) {
4252 if (p->is_Compiler_thread()) continue;
4253
4254 address pending = (address)p->current_pending_monitor();
4255 if (pending == monitor) { // found a match
4256 if (i < count) result->append(p); // save the first count matches
4257 i++;
4258 }
4259 }
4260 }
4261 return result;
4262 }
4263
4264
4265 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4266 assert(doLock ||
4267 Threads_lock->owned_by_self() ||
4268 SafepointSynchronize::is_at_safepoint(),
4269 "must grab Threads_lock or be at safepoint");
4270
4271 // NULL owner means not locked so we can skip the search
4272 if (owner == NULL) return NULL;
4273
4274 {
4275 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4276 ALL_JAVA_THREADS(p) {
4277 // first, see if owner is the address of a Java thread
4278 if (owner == (address)p) return p;
4279 }
4280 }
4281 // Cannot assert on lack of success here since this function may be
4282 // used by code that is trying to report useful problem information
4283 // like deadlock detection.
4284 if (UseHeavyMonitors) return NULL;
4285
4286 //
4287 // If we didn't find a matching Java thread and we didn't force use of
4288 // heavyweight monitors, then the owner is the stack address of the
4289 // Lock Word in the owning Java thread's stack.
4290 //
4291 JavaThread* the_owner = NULL;
4292 {
4293 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4294 ALL_JAVA_THREADS(q) {
4295 if (q->is_lock_owned(owner)) {
4296 the_owner = q;
4297 break;
4298 }
4299 }
4300 }
4301 // cannot assert on lack of success here; see above comment
4302 return the_owner;
4303 }
4304
4305 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4306 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4307 char buf[32];
4308 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4309
4310 st->print_cr("Full thread dump %s (%s %s):",
4311 Abstract_VM_Version::vm_name(),
4312 Abstract_VM_Version::vm_release(),
4313 Abstract_VM_Version::vm_info_string()
4314 );
4315 st->cr();
4316
4317 #if INCLUDE_ALL_GCS
4318 // Dump concurrent locks
4319 ConcurrentLocksDump concurrent_locks;
4320 if (print_concurrent_locks) {
4321 concurrent_locks.dump_at_safepoint();
4322 }
4323 #endif // INCLUDE_ALL_GCS
4324
4325 ALL_JAVA_THREADS(p) {
4326 ResourceMark rm;
4327 p->print_on(st);
4328 if (print_stacks) {
4329 if (internal_format) {
4330 p->trace_stack();
4331 } else {
4332 p->print_stack_on(st);
4333 }
4334 }
4335 st->cr();
4336 #if INCLUDE_ALL_GCS
4337 if (print_concurrent_locks) {
4338 concurrent_locks.print_locks_on(p, st);
4339 }
4340 #endif // INCLUDE_ALL_GCS
4341 }
4342
4343 VMThread::vm_thread()->print_on(st);
4344 st->cr();
4345 Universe::heap()->print_gc_threads_on(st);
4346 WatcherThread* wt = WatcherThread::watcher_thread();
4347 if (wt != NULL) {
4348 wt->print_on(st);
4349 st->cr();
4350 }
4351 CompileBroker::print_compiler_threads_on(st);
4352 st->flush();
4353 }
4354
4355 // Threads::print_on_error() is called by fatal error handler. It's possible
4356 // that VM is not at safepoint and/or current thread is inside signal handler.
4357 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4358 // memory (even in resource area), it might deadlock the error handler.
4359 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4360 bool found_current = false;
4361 st->print_cr("Java Threads: ( => current thread )");
4362 ALL_JAVA_THREADS(thread) {
4363 bool is_current = (current == thread);
4364 found_current = found_current || is_current;
4365
4366 st->print("%s", is_current ? "=>" : " ");
4367
4368 st->print(PTR_FORMAT, thread);
4369 st->print(" ");
4370 thread->print_on_error(st, buf, buflen);
4371 st->cr();
4372 }
4373 st->cr();
4374
4375 st->print_cr("Other Threads:");
4376 if (VMThread::vm_thread()) {
4377 bool is_current = (current == VMThread::vm_thread());
4378 found_current = found_current || is_current;
4379 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4380
4381 st->print(PTR_FORMAT, VMThread::vm_thread());
4382 st->print(" ");
4383 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4384 st->cr();
4385 }
4386 WatcherThread* wt = WatcherThread::watcher_thread();
4387 if (wt != NULL) {
4388 bool is_current = (current == wt);
4389 found_current = found_current || is_current;
4390 st->print("%s", is_current ? "=>" : " ");
4391
4392 st->print(PTR_FORMAT, wt);
4393 st->print(" ");
4394 wt->print_on_error(st, buf, buflen);
4395 st->cr();
4396 }
4397 if (!found_current) {
4398 st->cr();
4399 st->print("=>" PTR_FORMAT " (exited) ", current);
4400 current->print_on_error(st, buf, buflen);
4401 st->cr();
4402 }
4403 }
4404
4405 // Internal SpinLock and Mutex
4406 // Based on ParkEvent
4407
4408 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4409 //
4410 // We employ SpinLocks _only for low-contention, fixed-length
4411 // short-duration critical sections where we're concerned
4412 // about native mutex_t or HotSpot Mutex:: latency.
4413 // The mux construct provides a spin-then-block mutual exclusion
4414 // mechanism.
4415 //
4416 // Testing has shown that contention on the ListLock guarding gFreeList
4417 // is common. If we implement ListLock as a simple SpinLock it's common
4418 // for the JVM to devolve to yielding with little progress. This is true
4419 // despite the fact that the critical sections protected by ListLock are
4420 // extremely short.
4421 //
4422 // TODO-FIXME: ListLock should be of type SpinLock.
4423 // We should make this a 1st-class type, integrated into the lock
4424 // hierarchy as leaf-locks. Critically, the SpinLock structure
4425 // should have sufficient padding to avoid false-sharing and excessive
4426 // cache-coherency traffic.
4427
4428
4429 typedef volatile int SpinLockT ;
4430
4431 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4432 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4433 return ; // normal fast-path return
4434 }
4435
4436 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4437 TEVENT (SpinAcquire - ctx) ;
4438 int ctr = 0 ;
4439 int Yields = 0 ;
4440 for (;;) {
4441 while (*adr != 0) {
4442 ++ctr ;
4443 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4444 if (Yields > 5) {
4445 os::naked_short_sleep(1);
4446 } else {
4447 os::NakedYield() ;
4448 ++Yields ;
4449 }
4450 } else {
4451 SpinPause() ;
4452 }
4453 }
4454 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4455 }
4456 }
4457
4458 void Thread::SpinRelease (volatile int * adr) {
4459 assert (*adr != 0, "invariant") ;
4460 OrderAccess::fence() ; // guarantee at least release consistency.
4461 // Roach-motel semantics.
4462 // It's safe if subsequent LDs and STs float "up" into the critical section,
4463 // but prior LDs and STs within the critical section can't be allowed
4464 // to reorder or float past the ST that releases the lock.
4465 *adr = 0 ;
4466 }
4467
4468 // muxAcquire and muxRelease:
4469 //
4470 // * muxAcquire and muxRelease support a single-word lock-word construct.
4471 // The LSB of the word is set IFF the lock is held.
4472 // The remainder of the word points to the head of a singly-linked list
4473 // of threads blocked on the lock.
4474 //
4475 // * The current implementation of muxAcquire-muxRelease uses its own
4476 // dedicated Thread._MuxEvent instance. If we're interested in
4477 // minimizing the peak number of extant ParkEvent instances then
4478 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4479 // as certain invariants were satisfied. Specifically, care would need
4480 // to be taken with regards to consuming unpark() "permits".
4481 // A safe rule of thumb is that a thread would never call muxAcquire()
4482 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4483 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4484 // consume an unpark() permit intended for monitorenter, for instance.
4485 // One way around this would be to widen the restricted-range semaphore
4486 // implemented in park(). Another alternative would be to provide
4487 // multiple instances of the PlatformEvent() for each thread. One
4488 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4489 //
4490 // * Usage:
4491 // -- Only as leaf locks
4492 // -- for short-term locking only as muxAcquire does not perform
4493 // thread state transitions.
4494 //
4495 // Alternatives:
4496 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4497 // but with parking or spin-then-park instead of pure spinning.
4498 // * Use Taura-Oyama-Yonenzawa locks.
4499 // * It's possible to construct a 1-0 lock if we encode the lockword as
4500 // (List,LockByte). Acquire will CAS the full lockword while Release
4501 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4502 // acquiring threads use timers (ParkTimed) to detect and recover from
4503 // the stranding window. Thread/Node structures must be aligned on 256-byte
4504 // boundaries by using placement-new.
4505 // * Augment MCS with advisory back-link fields maintained with CAS().
4506 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4507 // The validity of the backlinks must be ratified before we trust the value.
4508 // If the backlinks are invalid the exiting thread must back-track through the
4509 // the forward links, which are always trustworthy.
4510 // * Add a successor indication. The LockWord is currently encoded as
4511 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4512 // to provide the usual futile-wakeup optimization.
4513 // See RTStt for details.
4514 // * Consider schedctl.sc_nopreempt to cover the critical section.
4515 //
4516
4517
4518 typedef volatile intptr_t MutexT ; // Mux Lock-word
4519 enum MuxBits { LOCKBIT = 1 } ;
4520
4521 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4522 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4523 if (w == 0) return ;
4524 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4525 return ;
4526 }
4527
4528 TEVENT (muxAcquire - Contention) ;
4529 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4530 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4531 for (;;) {
4532 int its = (os::is_MP() ? 100 : 0) + 1 ;
4533
4534 // Optional spin phase: spin-then-park strategy
4535 while (--its >= 0) {
4536 w = *Lock ;
4537 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4538 return ;
4539 }
4540 }
4541
4542 Self->reset() ;
4543 Self->OnList = intptr_t(Lock) ;
4544 // The following fence() isn't _strictly necessary as the subsequent
4545 // CAS() both serializes execution and ratifies the fetched *Lock value.
4546 OrderAccess::fence();
4547 for (;;) {
4548 w = *Lock ;
4549 if ((w & LOCKBIT) == 0) {
4550 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4551 Self->OnList = 0 ; // hygiene - allows stronger asserts
4552 return ;
4553 }
4554 continue ; // Interference -- *Lock changed -- Just retry
4555 }
4556 assert (w & LOCKBIT, "invariant") ;
4557 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4558 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4559 }
4560
4561 while (Self->OnList != 0) {
4562 Self->park() ;
4563 }
4564 }
4565 }
4566
4567 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4568 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4569 if (w == 0) return ;
4570 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4571 return ;
4572 }
4573
4574 TEVENT (muxAcquire - Contention) ;
4575 ParkEvent * ReleaseAfter = NULL ;
4576 if (ev == NULL) {
4577 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4578 }
4579 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4580 for (;;) {
4581 guarantee (ev->OnList == 0, "invariant") ;
4582 int its = (os::is_MP() ? 100 : 0) + 1 ;
4583
4584 // Optional spin phase: spin-then-park strategy
4585 while (--its >= 0) {
4586 w = *Lock ;
4587 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4588 if (ReleaseAfter != NULL) {
4589 ParkEvent::Release (ReleaseAfter) ;
4590 }
4591 return ;
4592 }
4593 }
4594
4595 ev->reset() ;
4596 ev->OnList = intptr_t(Lock) ;
4597 // The following fence() isn't _strictly necessary as the subsequent
4598 // CAS() both serializes execution and ratifies the fetched *Lock value.
4599 OrderAccess::fence();
4600 for (;;) {
4601 w = *Lock ;
4602 if ((w & LOCKBIT) == 0) {
4603 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4604 ev->OnList = 0 ;
4605 // We call ::Release while holding the outer lock, thus
4606 // artificially lengthening the critical section.
4607 // Consider deferring the ::Release() until the subsequent unlock(),
4608 // after we've dropped the outer lock.
4609 if (ReleaseAfter != NULL) {
4610 ParkEvent::Release (ReleaseAfter) ;
4611 }
4612 return ;
4613 }
4614 continue ; // Interference -- *Lock changed -- Just retry
4615 }
4616 assert (w & LOCKBIT, "invariant") ;
4617 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4618 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4619 }
4620
4621 while (ev->OnList != 0) {
4622 ev->park() ;
4623 }
4624 }
4625 }
4626
4627 // Release() must extract a successor from the list and then wake that thread.
4628 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4629 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4630 // Release() would :
4631 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4632 // (B) Extract a successor from the private list "in-hand"
4633 // (C) attempt to CAS() the residual back into *Lock over null.
4634 // If there were any newly arrived threads and the CAS() would fail.
4635 // In that case Release() would detach the RATs, re-merge the list in-hand
4636 // with the RATs and repeat as needed. Alternately, Release() might
4637 // detach and extract a successor, but then pass the residual list to the wakee.
4638 // The wakee would be responsible for reattaching and remerging before it
4639 // competed for the lock.
4640 //
4641 // Both "pop" and DMR are immune from ABA corruption -- there can be
4642 // multiple concurrent pushers, but only one popper or detacher.
4643 // This implementation pops from the head of the list. This is unfair,
4644 // but tends to provide excellent throughput as hot threads remain hot.
4645 // (We wake recently run threads first).
4646
4647 void Thread::muxRelease (volatile intptr_t * Lock) {
4648 for (;;) {
4649 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4650 assert (w & LOCKBIT, "invariant") ;
4651 if (w == LOCKBIT) return ;
4652 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4653 assert (List != NULL, "invariant") ;
4654 assert (List->OnList == intptr_t(Lock), "invariant") ;
4655 ParkEvent * nxt = List->ListNext ;
4656
4657 // The following CAS() releases the lock and pops the head element.
4658 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4659 continue ;
4660 }
4661 List->OnList = 0 ;
4662 OrderAccess::fence() ;
4663 List->unpark () ;
4664 return ;
4665 }
4666 }
4667
4668
4669 void Threads::verify() {
4670 ALL_JAVA_THREADS(p) {
4671 p->verify();
4672 }
4673 VMThread* thread = VMThread::vm_thread();
4674 if (thread != NULL) thread->verify();
4675 }