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