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/oopFactory.hpp"
38 #include "memory/universe.inline.hpp"
39 #include "oops/instanceKlass.hpp"
40 #include "oops/objArrayOop.hpp"
41 #include "oops/oop.inline.hpp"
42 #include "oops/symbol.hpp"
43 #include "prims/jvm_misc.hpp"
44 #include "prims/jvmtiExport.hpp"
45 #include "prims/jvmtiThreadState.hpp"
46 #include "prims/privilegedStack.hpp"
47 #include "runtime/aprofiler.hpp"
48 #include "runtime/arguments.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/deoptimization.hpp"
51 #include "runtime/fprofiler.hpp"
52 #include "runtime/frame.inline.hpp"
53 #include "runtime/init.hpp"
54 #include "runtime/interfaceSupport.hpp"
55 #include "runtime/java.hpp"
56 #include "runtime/javaCalls.hpp"
57 #include "runtime/jniPeriodicChecker.hpp"
58 #include "runtime/memprofiler.hpp"
59 #include "runtime/mutexLocker.hpp"
60 #include "runtime/objectMonitor.hpp"
61 #include "runtime/osThread.hpp"
62 #include "runtime/safepoint.hpp"
63 #include "runtime/sharedRuntime.hpp"
64 #include "runtime/statSampler.hpp"
65 #include "runtime/stubRoutines.hpp"
66 #include "runtime/task.hpp"
67 #include "runtime/threadCritical.hpp"
68 #include "runtime/threadLocalStorage.hpp"
69 #include "runtime/vframe.hpp"
70 #include "runtime/vframeArray.hpp"
71 #include "runtime/vframe_hp.hpp"
72 #include "runtime/vmThread.hpp"
73 #include "runtime/vm_operations.hpp"
74 #include "services/attachListener.hpp"
75 #include "services/management.hpp"
76 #include "services/memTracker.hpp"
77 #include "services/threadService.hpp"
78 #include "trace/tracing.hpp"
79 #include "trace/traceMacros.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 : os::malloc(aligned_size, flags, CURRENT_PC);
181 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
182 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
183 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
184 "JavaThread alignment code overflowed allocated storage");
185 if (TraceBiasedLocking) {
186 if (aligned_addr != real_malloc_addr)
187 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
188 real_malloc_addr, aligned_addr);
189 }
190 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
191 return aligned_addr;
192 } else {
193 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
194 : os::malloc(size, flags, CURRENT_PC);
195 }
196 }
197
198 void Thread::operator delete(void* p) {
199 if (UseBiasedLocking) {
200 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
201 FreeHeap(real_malloc_addr, mtThread);
202 } else {
203 FreeHeap(p, mtThread);
204 }
205 }
206
207
208 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
209 // JavaThread
210
211
212 Thread::Thread() {
213 // stack and get_thread
214 set_stack_base(NULL);
215 set_stack_size(0);
216 set_self_raw_id(0);
217 set_lgrp_id(-1);
218
219 // allocated data structures
220 set_osthread(NULL);
221 set_resource_area(new (mtThread)ResourceArea());
222 set_handle_area(new (mtThread) HandleArea(NULL));
223 set_active_handles(NULL);
224 set_free_handle_block(NULL);
225 set_last_handle_mark(NULL);
226
227 // This initial value ==> never claimed.
228 _oops_do_parity = 0;
229
230 // the handle mark links itself to last_handle_mark
231 new HandleMark(this);
232
233 // plain initialization
234 debug_only(_owned_locks = NULL;)
235 debug_only(_allow_allocation_count = 0;)
236 NOT_PRODUCT(_allow_safepoint_count = 0;)
237 NOT_PRODUCT(_skip_gcalot = false;)
238 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
239 _jvmti_env_iteration_count = 0;
240 set_allocated_bytes(0);
241 set_trace_buffer(NULL);
242 _vm_operation_started_count = 0;
243 _vm_operation_completed_count = 0;
244 _current_pending_monitor = NULL;
245 _current_pending_monitor_is_from_java = true;
246 _current_waiting_monitor = NULL;
247 _num_nested_signal = 0;
248 omFreeList = NULL ;
249 omFreeCount = 0 ;
250 omFreeProvision = 32 ;
251 omInUseList = NULL ;
252 omInUseCount = 0 ;
253
254 #ifdef ASSERT
255 _visited_for_critical_count = false;
256 #endif
257
258 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
259 _suspend_flags = 0;
260
261 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
262 _hashStateX = os::random() ;
263 _hashStateY = 842502087 ;
264 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
265 _hashStateW = 273326509 ;
266
267 _OnTrap = 0 ;
268 _schedctl = NULL ;
269 _Stalled = 0 ;
270 _TypeTag = 0x2BAD ;
271
272 // Many of the following fields are effectively final - immutable
273 // Note that nascent threads can't use the Native Monitor-Mutex
274 // construct until the _MutexEvent is initialized ...
275 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
276 // we might instead use a stack of ParkEvents that we could provision on-demand.
277 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
278 // and ::Release()
279 _ParkEvent = ParkEvent::Allocate (this) ;
280 _SleepEvent = ParkEvent::Allocate (this) ;
281 _MutexEvent = ParkEvent::Allocate (this) ;
282 _MuxEvent = ParkEvent::Allocate (this) ;
283
284 #ifdef CHECK_UNHANDLED_OOPS
285 if (CheckUnhandledOops) {
286 _unhandled_oops = new UnhandledOops(this);
287 }
288 #endif // CHECK_UNHANDLED_OOPS
289 #ifdef ASSERT
290 if (UseBiasedLocking) {
291 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
292 assert(this == _real_malloc_address ||
293 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
294 "bug in forced alignment of thread objects");
295 }
296 #endif /* ASSERT */
297 }
298
299 void Thread::initialize_thread_local_storage() {
300 // Note: Make sure this method only calls
301 // non-blocking operations. Otherwise, it might not work
302 // with the thread-startup/safepoint interaction.
303
304 // During Java thread startup, safepoint code should allow this
305 // method to complete because it may need to allocate memory to
306 // store information for the new thread.
307
308 // initialize structure dependent on thread local storage
309 ThreadLocalStorage::set_thread(this);
310
311 // set up any platform-specific state.
312 os::initialize_thread();
313 }
314
315 void Thread::record_stack_base_and_size() {
316 set_stack_base(os::current_stack_base());
317 set_stack_size(os::current_stack_size());
318
319 // record thread's native stack, stack grows downward
320 address vm_base = _stack_base - _stack_size;
321 MemTracker::record_virtual_memory_reserve(vm_base, _stack_size,
322 CURRENT_PC, this);
323 MemTracker::record_virtual_memory_type(vm_base, mtThreadStack);
324 }
325
326
327 Thread::~Thread() {
328 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
329 ObjectSynchronizer::omFlush (this) ;
330
331 MemTracker::record_virtual_memory_release((_stack_base - _stack_size),
332 _stack_size, this);
333
334 // deallocate data structures
335 delete resource_area();
336 // since the handle marks are using the handle area, we have to deallocated the root
337 // handle mark before deallocating the thread's handle area,
338 assert(last_handle_mark() != NULL, "check we have an element");
339 delete last_handle_mark();
340 assert(last_handle_mark() == NULL, "check we have reached the end");
341
342 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
343 // We NULL out the fields for good hygiene.
344 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
345 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
346 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
347 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
348
349 delete handle_area();
350
351 // osthread() can be NULL, if creation of thread failed.
352 if (osthread() != NULL) os::free_thread(osthread());
353
354 delete _SR_lock;
355
356 // clear thread local storage if the Thread is deleting itself
357 if (this == Thread::current()) {
358 ThreadLocalStorage::set_thread(NULL);
359 } else {
360 // In the case where we're not the current thread, invalidate all the
361 // caches in case some code tries to get the current thread or the
362 // thread that was destroyed, and gets stale information.
363 ThreadLocalStorage::invalidate_all();
364 }
365 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
366 }
367
368 // NOTE: dummy function for assertion purpose.
369 void Thread::run() {
370 ShouldNotReachHere();
371 }
372
373 #ifdef ASSERT
374 // Private method to check for dangling thread pointer
375 void check_for_dangling_thread_pointer(Thread *thread) {
376 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
377 "possibility of dangling Thread pointer");
378 }
379 #endif
380
381
382 #ifndef PRODUCT
383 // Tracing method for basic thread operations
384 void Thread::trace(const char* msg, const Thread* const thread) {
385 if (!TraceThreadEvents) return;
386 ResourceMark rm;
387 ThreadCritical tc;
388 const char *name = "non-Java thread";
389 int prio = -1;
390 if (thread->is_Java_thread()
391 && !thread->is_Compiler_thread()) {
392 // The Threads_lock must be held to get information about
393 // this thread but may not be in some situations when
394 // tracing thread events.
395 bool release_Threads_lock = false;
396 if (!Threads_lock->owned_by_self()) {
397 Threads_lock->lock();
398 release_Threads_lock = true;
399 }
400 JavaThread* jt = (JavaThread *)thread;
401 name = (char *)jt->get_thread_name();
402 oop thread_oop = jt->threadObj();
403 if (thread_oop != NULL) {
404 prio = java_lang_Thread::priority(thread_oop);
405 }
406 if (release_Threads_lock) {
407 Threads_lock->unlock();
408 }
409 }
410 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
411 }
412 #endif
413
414
415 ThreadPriority Thread::get_priority(const Thread* const thread) {
416 trace("get priority", thread);
417 ThreadPriority priority;
418 // Can return an error!
419 (void)os::get_priority(thread, priority);
420 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
421 return priority;
422 }
423
424 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
425 trace("set priority", thread);
426 debug_only(check_for_dangling_thread_pointer(thread);)
427 // Can return an error!
428 (void)os::set_priority(thread, priority);
429 }
430
431
432 void Thread::start(Thread* thread) {
433 trace("start", thread);
434 // Start is different from resume in that its safety is guaranteed by context or
435 // being called from a Java method synchronized on the Thread object.
436 if (!DisableStartThread) {
437 if (thread->is_Java_thread()) {
438 // Initialize the thread state to RUNNABLE before starting this thread.
439 // Can not set it after the thread started because we do not know the
440 // exact thread state at that time. It could be in MONITOR_WAIT or
441 // in SLEEPING or some other state.
442 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
443 java_lang_Thread::RUNNABLE);
444 }
445 os::start_thread(thread);
446 }
447 }
448
449 // Enqueue a VM_Operation to do the job for us - sometime later
450 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
451 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
452 VMThread::execute(vm_stop);
453 }
454
455
456 //
457 // Check if an external suspend request has completed (or has been
458 // cancelled). Returns true if the thread is externally suspended and
459 // false otherwise.
460 //
461 // The bits parameter returns information about the code path through
462 // the routine. Useful for debugging:
463 //
464 // set in is_ext_suspend_completed():
465 // 0x00000001 - routine was entered
466 // 0x00000010 - routine return false at end
467 // 0x00000100 - thread exited (return false)
468 // 0x00000200 - suspend request cancelled (return false)
469 // 0x00000400 - thread suspended (return true)
470 // 0x00001000 - thread is in a suspend equivalent state (return true)
471 // 0x00002000 - thread is native and walkable (return true)
472 // 0x00004000 - thread is native_trans and walkable (needed retry)
473 //
474 // set in wait_for_ext_suspend_completion():
475 // 0x00010000 - routine was entered
476 // 0x00020000 - suspend request cancelled before loop (return false)
477 // 0x00040000 - thread suspended before loop (return true)
478 // 0x00080000 - suspend request cancelled in loop (return false)
479 // 0x00100000 - thread suspended in loop (return true)
480 // 0x00200000 - suspend not completed during retry loop (return false)
481 //
482
483 // Helper class for tracing suspend wait debug bits.
484 //
485 // 0x00000100 indicates that the target thread exited before it could
486 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
487 // 0x00080000 each indicate a cancelled suspend request so they don't
488 // count as wait failures either.
489 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
490
491 class TraceSuspendDebugBits : public StackObj {
492 private:
493 JavaThread * jt;
494 bool is_wait;
495 bool called_by_wait; // meaningful when !is_wait
496 uint32_t * bits;
497
498 public:
499 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
500 uint32_t *_bits) {
501 jt = _jt;
502 is_wait = _is_wait;
503 called_by_wait = _called_by_wait;
504 bits = _bits;
505 }
506
507 ~TraceSuspendDebugBits() {
508 if (!is_wait) {
509 #if 1
510 // By default, don't trace bits for is_ext_suspend_completed() calls.
511 // That trace is very chatty.
512 return;
513 #else
514 if (!called_by_wait) {
515 // If tracing for is_ext_suspend_completed() is enabled, then only
516 // trace calls to it from wait_for_ext_suspend_completion()
517 return;
518 }
519 #endif
520 }
521
522 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
523 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
524 MutexLocker ml(Threads_lock); // needed for get_thread_name()
525 ResourceMark rm;
526
527 tty->print_cr(
528 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
529 jt->get_thread_name(), *bits);
530
531 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
532 }
533 }
534 }
535 };
536 #undef DEBUG_FALSE_BITS
537
538
539 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
540 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
541
542 bool did_trans_retry = false; // only do thread_in_native_trans retry once
543 bool do_trans_retry; // flag to force the retry
544
545 *bits |= 0x00000001;
546
547 do {
548 do_trans_retry = false;
549
550 if (is_exiting()) {
551 // Thread is in the process of exiting. This is always checked
552 // first to reduce the risk of dereferencing a freed JavaThread.
553 *bits |= 0x00000100;
554 return false;
555 }
556
557 if (!is_external_suspend()) {
558 // Suspend request is cancelled. This is always checked before
559 // is_ext_suspended() to reduce the risk of a rogue resume
560 // confusing the thread that made the suspend request.
561 *bits |= 0x00000200;
562 return false;
563 }
564
565 if (is_ext_suspended()) {
566 // thread is suspended
567 *bits |= 0x00000400;
568 return true;
569 }
570
571 // Now that we no longer do hard suspends of threads running
572 // native code, the target thread can be changing thread state
573 // while we are in this routine:
574 //
575 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
576 //
577 // We save a copy of the thread state as observed at this moment
578 // and make our decision about suspend completeness based on the
579 // copy. This closes the race where the thread state is seen as
580 // _thread_in_native_trans in the if-thread_blocked check, but is
581 // seen as _thread_blocked in if-thread_in_native_trans check.
582 JavaThreadState save_state = thread_state();
583
584 if (save_state == _thread_blocked && is_suspend_equivalent()) {
585 // If the thread's state is _thread_blocked and this blocking
586 // condition is known to be equivalent to a suspend, then we can
587 // consider the thread to be externally suspended. This means that
588 // the code that sets _thread_blocked has been modified to do
589 // self-suspension if the blocking condition releases. We also
590 // used to check for CONDVAR_WAIT here, but that is now covered by
591 // the _thread_blocked with self-suspension check.
592 //
593 // Return true since we wouldn't be here unless there was still an
594 // external suspend request.
595 *bits |= 0x00001000;
596 return true;
597 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
598 // Threads running native code will self-suspend on native==>VM/Java
599 // transitions. If its stack is walkable (should always be the case
600 // unless this function is called before the actual java_suspend()
601 // call), then the wait is done.
602 *bits |= 0x00002000;
603 return true;
604 } else if (!called_by_wait && !did_trans_retry &&
605 save_state == _thread_in_native_trans &&
606 frame_anchor()->walkable()) {
607 // The thread is transitioning from thread_in_native to another
608 // thread state. check_safepoint_and_suspend_for_native_trans()
609 // will force the thread to self-suspend. If it hasn't gotten
610 // there yet we may have caught the thread in-between the native
611 // code check above and the self-suspend. Lucky us. If we were
612 // called by wait_for_ext_suspend_completion(), then it
613 // will be doing the retries so we don't have to.
614 //
615 // Since we use the saved thread state in the if-statement above,
616 // there is a chance that the thread has already transitioned to
617 // _thread_blocked by the time we get here. In that case, we will
618 // make a single unnecessary pass through the logic below. This
619 // doesn't hurt anything since we still do the trans retry.
620
621 *bits |= 0x00004000;
622
623 // Once the thread leaves thread_in_native_trans for another
624 // thread state, we break out of this retry loop. We shouldn't
625 // need this flag to prevent us from getting back here, but
626 // sometimes paranoia is good.
627 did_trans_retry = true;
628
629 // We wait for the thread to transition to a more usable state.
630 for (int i = 1; i <= SuspendRetryCount; i++) {
631 // We used to do an "os::yield_all(i)" call here with the intention
632 // that yielding would increase on each retry. However, the parameter
633 // is ignored on Linux which means the yield didn't scale up. Waiting
634 // on the SR_lock below provides a much more predictable scale up for
635 // the delay. It also provides a simple/direct point to check for any
636 // safepoint requests from the VMThread
637
638 // temporarily drops SR_lock while doing wait with safepoint check
639 // (if we're a JavaThread - the WatcherThread can also call this)
640 // and increase delay with each retry
641 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
642
643 // check the actual thread state instead of what we saved above
644 if (thread_state() != _thread_in_native_trans) {
645 // the thread has transitioned to another thread state so
646 // try all the checks (except this one) one more time.
647 do_trans_retry = true;
648 break;
649 }
650 } // end retry loop
651
652
653 }
654 } while (do_trans_retry);
655
656 *bits |= 0x00000010;
657 return false;
658 }
659
660 //
661 // Wait for an external suspend request to complete (or be cancelled).
662 // Returns true if the thread is externally suspended and false otherwise.
663 //
664 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
665 uint32_t *bits) {
666 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
667 false /* !called_by_wait */, bits);
668
669 // local flag copies to minimize SR_lock hold time
670 bool is_suspended;
671 bool pending;
672 uint32_t reset_bits;
673
674 // set a marker so is_ext_suspend_completed() knows we are the caller
675 *bits |= 0x00010000;
676
677 // We use reset_bits to reinitialize the bits value at the top of
678 // each retry loop. This allows the caller to make use of any
679 // unused bits for their own marking purposes.
680 reset_bits = *bits;
681
682 {
683 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
684 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
685 delay, bits);
686 pending = is_external_suspend();
687 }
688 // must release SR_lock to allow suspension to complete
689
690 if (!pending) {
691 // A cancelled suspend request is the only false return from
692 // is_ext_suspend_completed() that keeps us from entering the
693 // retry loop.
694 *bits |= 0x00020000;
695 return false;
696 }
697
698 if (is_suspended) {
699 *bits |= 0x00040000;
700 return true;
701 }
702
703 for (int i = 1; i <= retries; i++) {
704 *bits = reset_bits; // reinit to only track last retry
705
706 // We used to do an "os::yield_all(i)" call here with the intention
707 // that yielding would increase on each retry. However, the parameter
708 // is ignored on Linux which means the yield didn't scale up. Waiting
709 // on the SR_lock below provides a much more predictable scale up for
710 // the delay. It also provides a simple/direct point to check for any
711 // safepoint requests from the VMThread
712
713 {
714 MutexLocker ml(SR_lock());
715 // wait with safepoint check (if we're a JavaThread - the WatcherThread
716 // can also call this) and increase delay with each retry
717 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
718
719 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
720 delay, bits);
721
722 // It is possible for the external suspend request to be cancelled
723 // (by a resume) before the actual suspend operation is completed.
724 // Refresh our local copy to see if we still need to wait.
725 pending = is_external_suspend();
726 }
727
728 if (!pending) {
729 // A cancelled suspend request is the only false return from
730 // is_ext_suspend_completed() that keeps us from staying in the
731 // retry loop.
732 *bits |= 0x00080000;
733 return false;
734 }
735
736 if (is_suspended) {
737 *bits |= 0x00100000;
738 return true;
739 }
740 } // end retry loop
741
742 // thread did not suspend after all our retries
743 *bits |= 0x00200000;
744 return false;
745 }
746
747 #ifndef PRODUCT
748 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
749
750 // This should not need to be atomic as the only way for simultaneous
751 // updates is via interrupts. Even then this should be rare or non-existant
752 // and we don't care that much anyway.
753
754 int index = _jmp_ring_index;
755 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
756 _jmp_ring[index]._target = (intptr_t) target;
757 _jmp_ring[index]._instruction = (intptr_t) instr;
758 _jmp_ring[index]._file = file;
759 _jmp_ring[index]._line = line;
760 }
761 #endif /* PRODUCT */
762
763 // Called by flat profiler
764 // Callers have already called wait_for_ext_suspend_completion
765 // The assertion for that is currently too complex to put here:
766 bool JavaThread::profile_last_Java_frame(frame* _fr) {
767 bool gotframe = false;
768 // self suspension saves needed state.
769 if (has_last_Java_frame() && _anchor.walkable()) {
770 *_fr = pd_last_frame();
771 gotframe = true;
772 }
773 return gotframe;
774 }
775
776 void Thread::interrupt(Thread* thread) {
777 trace("interrupt", thread);
778 debug_only(check_for_dangling_thread_pointer(thread);)
779 os::interrupt(thread);
780 }
781
782 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
783 trace("is_interrupted", thread);
784 debug_only(check_for_dangling_thread_pointer(thread);)
785 // Note: If clear_interrupted==false, this simply fetches and
786 // returns the value of the field osthread()->interrupted().
787 return os::is_interrupted(thread, clear_interrupted);
788 }
789
790
791 // GC Support
792 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
793 jint thread_parity = _oops_do_parity;
794 if (thread_parity != strong_roots_parity) {
795 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
796 if (res == thread_parity) {
797 return true;
798 } else {
799 guarantee(res == strong_roots_parity, "Or else what?");
800 assert(SharedHeap::heap()->workers()->active_workers() > 0,
801 "Should only fail when parallel.");
802 return false;
803 }
804 }
805 assert(SharedHeap::heap()->workers()->active_workers() > 0,
806 "Should only fail when parallel.");
807 return false;
808 }
809
810 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
811 active_handles()->oops_do(f);
812 // Do oop for ThreadShadow
813 f->do_oop((oop*)&_pending_exception);
814 handle_area()->oops_do(f);
815 }
816
817 void Thread::nmethods_do(CodeBlobClosure* cf) {
818 // no nmethods in a generic thread...
819 }
820
821 void Thread::print_on(outputStream* st) const {
822 // get_priority assumes osthread initialized
823 if (osthread() != NULL) {
824 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
825 osthread()->print_on(st);
826 }
827 debug_only(if (WizardMode) print_owned_locks_on(st);)
828 }
829
830 // Thread::print_on_error() is called by fatal error handler. Don't use
831 // any lock or allocate memory.
832 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
833 if (is_VM_thread()) st->print("VMThread");
834 else if (is_Compiler_thread()) st->print("CompilerThread");
835 else if (is_Java_thread()) st->print("JavaThread");
836 else if (is_GC_task_thread()) st->print("GCTaskThread");
837 else if (is_Watcher_thread()) st->print("WatcherThread");
838 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
839 else st->print("Thread");
840
841 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
842 _stack_base - _stack_size, _stack_base);
843
844 if (osthread()) {
845 st->print(" [id=%d]", osthread()->thread_id());
846 }
847 }
848
849 #ifdef ASSERT
850 void Thread::print_owned_locks_on(outputStream* st) const {
851 Monitor *cur = _owned_locks;
852 if (cur == NULL) {
853 st->print(" (no locks) ");
854 } else {
855 st->print_cr(" Locks owned:");
856 while(cur) {
857 cur->print_on(st);
858 cur = cur->next();
859 }
860 }
861 }
862
863 static int ref_use_count = 0;
864
865 bool Thread::owns_locks_but_compiled_lock() const {
866 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
867 if (cur != Compile_lock) return true;
868 }
869 return false;
870 }
871
872
873 #endif
874
875 #ifndef PRODUCT
876
877 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
878 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
879 // no threads which allow_vm_block's are held
880 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
881 // Check if current thread is allowed to block at a safepoint
882 if (!(_allow_safepoint_count == 0))
883 fatal("Possible safepoint reached by thread that does not allow it");
884 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
885 fatal("LEAF method calling lock?");
886 }
887
888 #ifdef ASSERT
889 if (potential_vm_operation && is_Java_thread()
890 && !Universe::is_bootstrapping()) {
891 // Make sure we do not hold any locks that the VM thread also uses.
892 // This could potentially lead to deadlocks
893 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
894 // Threads_lock is special, since the safepoint synchronization will not start before this is
895 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
896 // since it is used to transfer control between JavaThreads and the VMThread
897 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
898 if ( (cur->allow_vm_block() &&
899 cur != Threads_lock &&
900 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
901 cur != VMOperationRequest_lock &&
902 cur != VMOperationQueue_lock) ||
903 cur->rank() == Mutex::special) {
904 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
905 }
906 }
907 }
908
909 if (GCALotAtAllSafepoints) {
910 // We could enter a safepoint here and thus have a gc
911 InterfaceSupport::check_gc_alot();
912 }
913 #endif
914 }
915 #endif
916
917 bool Thread::is_in_stack(address adr) const {
918 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
919 address end = os::current_stack_pointer();
920 if (stack_base() >= adr && adr >= end) return true;
921
922 return false;
923 }
924
925
926 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
927 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
928 // used for compilation in the future. If that change is made, the need for these methods
929 // should be revisited, and they should be removed if possible.
930
931 bool Thread::is_lock_owned(address adr) const {
932 return on_local_stack(adr);
933 }
934
935 bool Thread::set_as_starting_thread() {
936 // NOTE: this must be called inside the main thread.
937 return os::create_main_thread((JavaThread*)this);
938 }
939
940 static void initialize_class(Symbol* class_name, TRAPS) {
941 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
942 instanceKlass::cast(klass)->initialize(CHECK);
943 }
944
945
946 // Creates the initial ThreadGroup
947 static Handle create_initial_thread_group(TRAPS) {
948 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
949 instanceKlassHandle klass (THREAD, k);
950
951 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
952 {
953 JavaValue result(T_VOID);
954 JavaCalls::call_special(&result,
955 system_instance,
956 klass,
957 vmSymbols::object_initializer_name(),
958 vmSymbols::void_method_signature(),
959 CHECK_NH);
960 }
961 Universe::set_system_thread_group(system_instance());
962
963 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
964 {
965 JavaValue result(T_VOID);
966 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
967 JavaCalls::call_special(&result,
968 main_instance,
969 klass,
970 vmSymbols::object_initializer_name(),
971 vmSymbols::threadgroup_string_void_signature(),
972 system_instance,
973 string,
974 CHECK_NH);
975 }
976 return main_instance;
977 }
978
979 // Creates the initial Thread
980 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
981 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
982 instanceKlassHandle klass (THREAD, k);
983 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
984
985 java_lang_Thread::set_thread(thread_oop(), thread);
986 java_lang_Thread::set_priority(thread_oop(), NormPriority);
987 thread->set_threadObj(thread_oop());
988
989 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
990
991 JavaValue result(T_VOID);
992 JavaCalls::call_special(&result, thread_oop,
993 klass,
994 vmSymbols::object_initializer_name(),
995 vmSymbols::threadgroup_string_void_signature(),
996 thread_group,
997 string,
998 CHECK_NULL);
999 return thread_oop();
1000 }
1001
1002 static void call_initializeSystemClass(TRAPS) {
1003 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1004 instanceKlassHandle klass (THREAD, k);
1005
1006 JavaValue result(T_VOID);
1007 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1008 vmSymbols::void_method_signature(), CHECK);
1009 }
1010
1011 char java_runtime_name[128] = "";
1012
1013 // extract the JRE name from sun.misc.Version.java_runtime_name
1014 static const char* get_java_runtime_name(TRAPS) {
1015 klassOop k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1016 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1017 fieldDescriptor fd;
1018 bool found = k != NULL &&
1019 instanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1020 vmSymbols::string_signature(), &fd);
1021 if (found) {
1022 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1023 if (name_oop == NULL)
1024 return NULL;
1025 const char* name = java_lang_String::as_utf8_string(name_oop,
1026 java_runtime_name,
1027 sizeof(java_runtime_name));
1028 return name;
1029 } else {
1030 return NULL;
1031 }
1032 }
1033
1034 // General purpose hook into Java code, run once when the VM is initialized.
1035 // The Java library method itself may be changed independently from the VM.
1036 static void call_postVMInitHook(TRAPS) {
1037 klassOop k = SystemDictionary::PostVMInitHook_klass();
1038 instanceKlassHandle klass (THREAD, k);
1039 if (klass.not_null()) {
1040 JavaValue result(T_VOID);
1041 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1042 vmSymbols::void_method_signature(),
1043 CHECK);
1044 }
1045 }
1046
1047 static void reset_vm_info_property(TRAPS) {
1048 // the vm info string
1049 ResourceMark rm(THREAD);
1050 const char *vm_info = VM_Version::vm_info_string();
1051
1052 // java.lang.System class
1053 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1054 instanceKlassHandle klass (THREAD, k);
1055
1056 // setProperty arguments
1057 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1058 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1059
1060 // return value
1061 JavaValue r(T_OBJECT);
1062
1063 // public static String setProperty(String key, String value);
1064 JavaCalls::call_static(&r,
1065 klass,
1066 vmSymbols::setProperty_name(),
1067 vmSymbols::string_string_string_signature(),
1068 key_str,
1069 value_str,
1070 CHECK);
1071 }
1072
1073
1074 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1075 assert(thread_group.not_null(), "thread group should be specified");
1076 assert(threadObj() == NULL, "should only create Java thread object once");
1077
1078 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1079 instanceKlassHandle klass (THREAD, k);
1080 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1081
1082 java_lang_Thread::set_thread(thread_oop(), this);
1083 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1084 set_threadObj(thread_oop());
1085
1086 JavaValue result(T_VOID);
1087 if (thread_name != NULL) {
1088 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1089 // Thread gets assigned specified name and null target
1090 JavaCalls::call_special(&result,
1091 thread_oop,
1092 klass,
1093 vmSymbols::object_initializer_name(),
1094 vmSymbols::threadgroup_string_void_signature(),
1095 thread_group, // Argument 1
1096 name, // Argument 2
1097 THREAD);
1098 } else {
1099 // Thread gets assigned name "Thread-nnn" and null target
1100 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1101 JavaCalls::call_special(&result,
1102 thread_oop,
1103 klass,
1104 vmSymbols::object_initializer_name(),
1105 vmSymbols::threadgroup_runnable_void_signature(),
1106 thread_group, // Argument 1
1107 Handle(), // Argument 2
1108 THREAD);
1109 }
1110
1111
1112 if (daemon) {
1113 java_lang_Thread::set_daemon(thread_oop());
1114 }
1115
1116 if (HAS_PENDING_EXCEPTION) {
1117 return;
1118 }
1119
1120 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1121 Handle threadObj(this, this->threadObj());
1122
1123 JavaCalls::call_special(&result,
1124 thread_group,
1125 group,
1126 vmSymbols::add_method_name(),
1127 vmSymbols::thread_void_signature(),
1128 threadObj, // Arg 1
1129 THREAD);
1130
1131
1132 }
1133
1134 // NamedThread -- non-JavaThread subclasses with multiple
1135 // uniquely named instances should derive from this.
1136 NamedThread::NamedThread() : Thread() {
1137 _name = NULL;
1138 _processed_thread = NULL;
1139 }
1140
1141 NamedThread::~NamedThread() {
1142 if (_name != NULL) {
1143 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1144 _name = NULL;
1145 }
1146 }
1147
1148 void NamedThread::set_name(const char* format, ...) {
1149 guarantee(_name == NULL, "Only get to set name once.");
1150 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1151 guarantee(_name != NULL, "alloc failure");
1152 va_list ap;
1153 va_start(ap, format);
1154 jio_vsnprintf(_name, max_name_len, format, ap);
1155 va_end(ap);
1156 }
1157
1158 // ======= WatcherThread ========
1159
1160 // The watcher thread exists to simulate timer interrupts. It should
1161 // be replaced by an abstraction over whatever native support for
1162 // timer interrupts exists on the platform.
1163
1164 WatcherThread* WatcherThread::_watcher_thread = NULL;
1165 bool WatcherThread::_startable = false;
1166 volatile bool WatcherThread::_should_terminate = false;
1167
1168 WatcherThread::WatcherThread() : Thread() {
1169 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1170 if (os::create_thread(this, os::watcher_thread)) {
1171 _watcher_thread = this;
1172
1173 // Set the watcher thread to the highest OS priority which should not be
1174 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1175 // is created. The only normal thread using this priority is the reference
1176 // handler thread, which runs for very short intervals only.
1177 // If the VMThread's priority is not lower than the WatcherThread profiling
1178 // will be inaccurate.
1179 os::set_priority(this, MaxPriority);
1180 if (!DisableStartThread) {
1181 os::start_thread(this);
1182 }
1183 }
1184 }
1185
1186 jint WatcherThread::sleep() const {
1187 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1188
1189 // remaining will be zero if there are no tasks,
1190 // causing the WatcherThread to sleep until a task is
1191 // enrolled
1192 jint remaining = PeriodicTask::time_to_wait();
1193 jint time_slept = 0;
1194
1195 // we expect this to timeout - we only ever get unparked when
1196 // we should terminate or when a new task has been enrolled
1197 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1198
1199 jlong time_before_loop = os::javaTimeNanos();
1200
1201 for (;;) {
1202 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1203 jlong now = os::javaTimeNanos();
1204
1205 if (remaining == 0) {
1206 // if we didn't have any tasks we could have waited for a long time
1207 // consider the time_slept zero and reset time_before_loop
1208 time_slept = 0;
1209 time_before_loop = now;
1210 } else {
1211 // need to recalulate since we might have new tasks in _tasks
1212 time_slept = (jint) ((now - time_before_loop) / 1000000);
1213 }
1214
1215 // Change to task list or spurious wakeup of some kind
1216 if (timedout || _should_terminate) {
1217 break;
1218 }
1219
1220 remaining = PeriodicTask::time_to_wait();
1221 if (remaining == 0) {
1222 // Last task was just disenrolled so loop around and wait until
1223 // another task gets enrolled
1224 continue;
1225 }
1226
1227 remaining -= time_slept;
1228 if (remaining <= 0)
1229 break;
1230 }
1231
1232 return time_slept;
1233 }
1234
1235 void WatcherThread::run() {
1236 assert(this == watcher_thread(), "just checking");
1237
1238 this->record_stack_base_and_size();
1239 this->initialize_thread_local_storage();
1240 this->set_active_handles(JNIHandleBlock::allocate_block());
1241 while(!_should_terminate) {
1242 assert(watcher_thread() == Thread::current(), "thread consistency check");
1243 assert(watcher_thread() == this, "thread consistency check");
1244
1245 // Calculate how long it'll be until the next PeriodicTask work
1246 // should be done, and sleep that amount of time.
1247 jint time_waited = sleep();
1248
1249 if (is_error_reported()) {
1250 // A fatal error has happened, the error handler(VMError::report_and_die)
1251 // should abort JVM after creating an error log file. However in some
1252 // rare cases, the error handler itself might deadlock. Here we try to
1253 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1254 //
1255 // This code is in WatcherThread because WatcherThread wakes up
1256 // periodically so the fatal error handler doesn't need to do anything;
1257 // also because the WatcherThread is less likely to crash than other
1258 // threads.
1259
1260 for (;;) {
1261 if (!ShowMessageBoxOnError
1262 && (OnError == NULL || OnError[0] == '\0')
1263 && Arguments::abort_hook() == NULL) {
1264 os::sleep(this, 2 * 60 * 1000, false);
1265 fdStream err(defaultStream::output_fd());
1266 err.print_raw_cr("# [ timer expired, abort... ]");
1267 // skip atexit/vm_exit/vm_abort hooks
1268 os::die();
1269 }
1270
1271 // Wake up 5 seconds later, the fatal handler may reset OnError or
1272 // ShowMessageBoxOnError when it is ready to abort.
1273 os::sleep(this, 5 * 1000, false);
1274 }
1275 }
1276
1277 PeriodicTask::real_time_tick(time_waited);
1278 }
1279
1280 // Signal that it is terminated
1281 {
1282 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1283 _watcher_thread = NULL;
1284 Terminator_lock->notify();
1285 }
1286
1287 // Thread destructor usually does this..
1288 ThreadLocalStorage::set_thread(NULL);
1289 }
1290
1291 void WatcherThread::start() {
1292 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1293
1294 if (watcher_thread() == NULL && _startable) {
1295 _should_terminate = false;
1296 // Create the single instance of WatcherThread
1297 new WatcherThread();
1298 }
1299 }
1300
1301 void WatcherThread::make_startable() {
1302 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1303 _startable = true;
1304 }
1305
1306 void WatcherThread::stop() {
1307 {
1308 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1309 _should_terminate = true;
1310 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1311
1312 WatcherThread* watcher = watcher_thread();
1313 if (watcher != NULL)
1314 watcher->unpark();
1315 }
1316
1317 // it is ok to take late safepoints here, if needed
1318 MutexLocker mu(Terminator_lock);
1319
1320 while(watcher_thread() != NULL) {
1321 // This wait should make safepoint checks, wait without a timeout,
1322 // and wait as a suspend-equivalent condition.
1323 //
1324 // Note: If the FlatProfiler is running, then this thread is waiting
1325 // for the WatcherThread to terminate and the WatcherThread, via the
1326 // FlatProfiler task, is waiting for the external suspend request on
1327 // this thread to complete. wait_for_ext_suspend_completion() will
1328 // eventually timeout, but that takes time. Making this wait a
1329 // suspend-equivalent condition solves that timeout problem.
1330 //
1331 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1332 Mutex::_as_suspend_equivalent_flag);
1333 }
1334 }
1335
1336 void WatcherThread::unpark() {
1337 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1338 PeriodicTask_lock->notify();
1339 }
1340
1341 void WatcherThread::print_on(outputStream* st) const {
1342 st->print("\"%s\" ", name());
1343 Thread::print_on(st);
1344 st->cr();
1345 }
1346
1347 // ======= JavaThread ========
1348
1349 // A JavaThread is a normal Java thread
1350
1351 void JavaThread::initialize() {
1352 // Initialize fields
1353
1354 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1355 set_claimed_par_id(-1);
1356
1357 set_saved_exception_pc(NULL);
1358 set_threadObj(NULL);
1359 _anchor.clear();
1360 set_entry_point(NULL);
1361 set_jni_functions(jni_functions());
1362 set_callee_target(NULL);
1363 set_vm_result(NULL);
1364 set_vm_result_2(NULL);
1365 set_vframe_array_head(NULL);
1366 set_vframe_array_last(NULL);
1367 set_deferred_locals(NULL);
1368 set_deopt_mark(NULL);
1369 set_deopt_nmethod(NULL);
1370 clear_must_deopt_id();
1371 set_monitor_chunks(NULL);
1372 set_next(NULL);
1373 set_thread_state(_thread_new);
1374 set_recorder(NULL);
1375 _terminated = _not_terminated;
1376 _privileged_stack_top = NULL;
1377 _array_for_gc = NULL;
1378 _suspend_equivalent = false;
1379 _in_deopt_handler = 0;
1380 _doing_unsafe_access = false;
1381 _stack_guard_state = stack_guard_unused;
1382 _exception_oop = NULL;
1383 _exception_pc = 0;
1384 _exception_handler_pc = 0;
1385 _is_method_handle_return = 0;
1386 _jvmti_thread_state= NULL;
1387 _should_post_on_exceptions_flag = JNI_FALSE;
1388 _jvmti_get_loaded_classes_closure = NULL;
1389 _interp_only_mode = 0;
1390 _special_runtime_exit_condition = _no_async_condition;
1391 _pending_async_exception = NULL;
1392 _is_compiling = false;
1393 _thread_stat = NULL;
1394 _thread_stat = new ThreadStatistics();
1395 _blocked_on_compilation = false;
1396 _jni_active_critical = 0;
1397 _do_not_unlock_if_synchronized = false;
1398 _cached_monitor_info = NULL;
1399 _parker = Parker::Allocate(this) ;
1400
1401 #ifndef PRODUCT
1402 _jmp_ring_index = 0;
1403 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1404 record_jump(NULL, NULL, NULL, 0);
1405 }
1406 #endif /* PRODUCT */
1407
1408 set_thread_profiler(NULL);
1409 if (FlatProfiler::is_active()) {
1410 // This is where we would decide to either give each thread it's own profiler
1411 // or use one global one from FlatProfiler,
1412 // or up to some count of the number of profiled threads, etc.
1413 ThreadProfiler* pp = new ThreadProfiler();
1414 pp->engage();
1415 set_thread_profiler(pp);
1416 }
1417
1418 // Setup safepoint state info for this thread
1419 ThreadSafepointState::create(this);
1420
1421 debug_only(_java_call_counter = 0);
1422
1423 // JVMTI PopFrame support
1424 _popframe_condition = popframe_inactive;
1425 _popframe_preserved_args = NULL;
1426 _popframe_preserved_args_size = 0;
1427
1428 pd_initialize();
1429 }
1430
1431 #ifndef SERIALGC
1432 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1433 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1434 #endif // !SERIALGC
1435
1436 JavaThread::JavaThread(bool is_attaching_via_jni) :
1437 Thread()
1438 #ifndef SERIALGC
1439 , _satb_mark_queue(&_satb_mark_queue_set),
1440 _dirty_card_queue(&_dirty_card_queue_set)
1441 #endif // !SERIALGC
1442 {
1443 initialize();
1444 if (is_attaching_via_jni) {
1445 _jni_attach_state = _attaching_via_jni;
1446 } else {
1447 _jni_attach_state = _not_attaching_via_jni;
1448 }
1449 assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor");
1450 _safepoint_visible = false;
1451 }
1452
1453 bool JavaThread::reguard_stack(address cur_sp) {
1454 if (_stack_guard_state != stack_guard_yellow_disabled) {
1455 return true; // Stack already guarded or guard pages not needed.
1456 }
1457
1458 if (register_stack_overflow()) {
1459 // For those architectures which have separate register and
1460 // memory stacks, we must check the register stack to see if
1461 // it has overflowed.
1462 return false;
1463 }
1464
1465 // Java code never executes within the yellow zone: the latter is only
1466 // there to provoke an exception during stack banging. If java code
1467 // is executing there, either StackShadowPages should be larger, or
1468 // some exception code in c1, c2 or the interpreter isn't unwinding
1469 // when it should.
1470 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1471
1472 enable_stack_yellow_zone();
1473 return true;
1474 }
1475
1476 bool JavaThread::reguard_stack(void) {
1477 return reguard_stack(os::current_stack_pointer());
1478 }
1479
1480
1481 void JavaThread::block_if_vm_exited() {
1482 if (_terminated == _vm_exited) {
1483 // _vm_exited is set at safepoint, and Threads_lock is never released
1484 // we will block here forever
1485 Threads_lock->lock_without_safepoint_check();
1486 ShouldNotReachHere();
1487 }
1488 }
1489
1490
1491 // Remove this ifdef when C1 is ported to the compiler interface.
1492 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1493
1494 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1495 Thread()
1496 #ifndef SERIALGC
1497 , _satb_mark_queue(&_satb_mark_queue_set),
1498 _dirty_card_queue(&_dirty_card_queue_set)
1499 #endif // !SERIALGC
1500 {
1501 if (TraceThreadEvents) {
1502 tty->print_cr("creating thread %p", this);
1503 }
1504 initialize();
1505 _jni_attach_state = _not_attaching_via_jni;
1506 set_entry_point(entry_point);
1507 // Create the native thread itself.
1508 // %note runtime_23
1509 os::ThreadType thr_type = os::java_thread;
1510 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1511 os::java_thread;
1512 os::create_thread(this, thr_type, stack_sz);
1513 _safepoint_visible = false;
1514 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1515 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1516 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1517 // the exception consists of creating the exception object & initializing it, initialization
1518 // will leave the VM via a JavaCall and then all locks must be unlocked).
1519 //
1520 // The thread is still suspended when we reach here. Thread must be explicit started
1521 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1522 // by calling Threads:add. The reason why this is not done here, is because the thread
1523 // object must be fully initialized (take a look at JVM_Start)
1524 }
1525
1526 JavaThread::~JavaThread() {
1527 if (TraceThreadEvents) {
1528 tty->print_cr("terminate thread %p", this);
1529 }
1530
1531 // Info NMT that this JavaThread is exiting, its memory
1532 // recorder should be collected
1533 assert(!is_safepoint_visible(), "wrong state");
1534 MemTracker::thread_exiting(this);
1535
1536 // JSR166 -- return the parker to the free list
1537 Parker::Release(_parker);
1538 _parker = NULL ;
1539
1540 // Free any remaining previous UnrollBlock
1541 vframeArray* old_array = vframe_array_last();
1542
1543 if (old_array != NULL) {
1544 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1545 old_array->set_unroll_block(NULL);
1546 delete old_info;
1547 delete old_array;
1548 }
1549
1550 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1551 if (deferred != NULL) {
1552 // This can only happen if thread is destroyed before deoptimization occurs.
1553 assert(deferred->length() != 0, "empty array!");
1554 do {
1555 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1556 deferred->remove_at(0);
1557 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1558 delete dlv;
1559 } while (deferred->length() != 0);
1560 delete deferred;
1561 }
1562
1563 // All Java related clean up happens in exit
1564 ThreadSafepointState::destroy(this);
1565 if (_thread_profiler != NULL) delete _thread_profiler;
1566 if (_thread_stat != NULL) delete _thread_stat;
1567 }
1568
1569
1570 // The first routine called by a new Java thread
1571 void JavaThread::run() {
1572 // initialize thread-local alloc buffer related fields
1573 this->initialize_tlab();
1574
1575 // used to test validitity of stack trace backs
1576 this->record_base_of_stack_pointer();
1577
1578 // Record real stack base and size.
1579 this->record_stack_base_and_size();
1580
1581 // Initialize thread local storage; set before calling MutexLocker
1582 this->initialize_thread_local_storage();
1583
1584 this->create_stack_guard_pages();
1585
1586 this->cache_global_variables();
1587
1588 // Thread is now sufficient initialized to be handled by the safepoint code as being
1589 // in the VM. Change thread state from _thread_new to _thread_in_vm
1590 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1591
1592 assert(JavaThread::current() == this, "sanity check");
1593 assert(!Thread::current()->owns_locks(), "sanity check");
1594
1595 DTRACE_THREAD_PROBE(start, this);
1596
1597 // This operation might block. We call that after all safepoint checks for a new thread has
1598 // been completed.
1599 this->set_active_handles(JNIHandleBlock::allocate_block());
1600
1601 if (JvmtiExport::should_post_thread_life()) {
1602 JvmtiExport::post_thread_start(this);
1603 }
1604
1605 EVENT_BEGIN(ThreadStart, event);
1606 EVENT_COMMIT(event,
1607 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj())));
1608
1609 // We call another function to do the rest so we are sure that the stack addresses used
1610 // from there will be lower than the stack base just computed
1611 thread_main_inner();
1612
1613 // Note, thread is no longer valid at this point!
1614 }
1615
1616
1617 void JavaThread::thread_main_inner() {
1618 assert(JavaThread::current() == this, "sanity check");
1619 assert(this->threadObj() != NULL, "just checking");
1620
1621 // Execute thread entry point unless this thread has a pending exception
1622 // or has been stopped before starting.
1623 // Note: Due to JVM_StopThread we can have pending exceptions already!
1624 if (!this->has_pending_exception() &&
1625 !java_lang_Thread::is_stillborn(this->threadObj())) {
1626 {
1627 ResourceMark rm(this);
1628 this->set_native_thread_name(this->get_thread_name());
1629 }
1630 HandleMark hm(this);
1631 this->entry_point()(this, this);
1632 }
1633
1634 DTRACE_THREAD_PROBE(stop, this);
1635
1636 this->exit(false);
1637 delete this;
1638 }
1639
1640
1641 static void ensure_join(JavaThread* thread) {
1642 // We do not need to grap the Threads_lock, since we are operating on ourself.
1643 Handle threadObj(thread, thread->threadObj());
1644 assert(threadObj.not_null(), "java thread object must exist");
1645 ObjectLocker lock(threadObj, thread);
1646 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1647 thread->clear_pending_exception();
1648 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1649 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1650 // Clear the native thread instance - this makes isAlive return false and allows the join()
1651 // to complete once we've done the notify_all below
1652 java_lang_Thread::set_thread(threadObj(), NULL);
1653 lock.notify_all(thread);
1654 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1655 thread->clear_pending_exception();
1656 }
1657
1658
1659 // For any new cleanup additions, please check to see if they need to be applied to
1660 // cleanup_failed_attach_current_thread as well.
1661 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1662 assert(this == JavaThread::current(), "thread consistency check");
1663 if (!InitializeJavaLangSystem) return;
1664
1665 HandleMark hm(this);
1666 Handle uncaught_exception(this, this->pending_exception());
1667 this->clear_pending_exception();
1668 Handle threadObj(this, this->threadObj());
1669 assert(threadObj.not_null(), "Java thread object should be created");
1670
1671 if (get_thread_profiler() != NULL) {
1672 get_thread_profiler()->disengage();
1673 ResourceMark rm;
1674 get_thread_profiler()->print(get_thread_name());
1675 }
1676
1677
1678 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1679 {
1680 EXCEPTION_MARK;
1681
1682 CLEAR_PENDING_EXCEPTION;
1683 }
1684 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1685 // has to be fixed by a runtime query method
1686 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1687 // JSR-166: change call from from ThreadGroup.uncaughtException to
1688 // java.lang.Thread.dispatchUncaughtException
1689 if (uncaught_exception.not_null()) {
1690 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1691 {
1692 EXCEPTION_MARK;
1693 // Check if the method Thread.dispatchUncaughtException() exists. If so
1694 // call it. Otherwise we have an older library without the JSR-166 changes,
1695 // so call ThreadGroup.uncaughtException()
1696 KlassHandle recvrKlass(THREAD, threadObj->klass());
1697 CallInfo callinfo;
1698 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1699 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1700 vmSymbols::dispatchUncaughtException_name(),
1701 vmSymbols::throwable_void_signature(),
1702 KlassHandle(), false, false, THREAD);
1703 CLEAR_PENDING_EXCEPTION;
1704 methodHandle method = callinfo.selected_method();
1705 if (method.not_null()) {
1706 JavaValue result(T_VOID);
1707 JavaCalls::call_virtual(&result,
1708 threadObj, thread_klass,
1709 vmSymbols::dispatchUncaughtException_name(),
1710 vmSymbols::throwable_void_signature(),
1711 uncaught_exception,
1712 THREAD);
1713 } else {
1714 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1715 JavaValue result(T_VOID);
1716 JavaCalls::call_virtual(&result,
1717 group, thread_group,
1718 vmSymbols::uncaughtException_name(),
1719 vmSymbols::thread_throwable_void_signature(),
1720 threadObj, // Arg 1
1721 uncaught_exception, // Arg 2
1722 THREAD);
1723 }
1724 if (HAS_PENDING_EXCEPTION) {
1725 ResourceMark rm(this);
1726 jio_fprintf(defaultStream::error_stream(),
1727 "\nException: %s thrown from the UncaughtExceptionHandler"
1728 " in thread \"%s\"\n",
1729 Klass::cast(pending_exception()->klass())->external_name(),
1730 get_thread_name());
1731 CLEAR_PENDING_EXCEPTION;
1732 }
1733 }
1734 }
1735
1736 // Called before the java thread exit since we want to read info
1737 // from java_lang_Thread object
1738 EVENT_BEGIN(ThreadEnd, event);
1739 EVENT_COMMIT(event,
1740 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj())));
1741
1742 // Call after last event on thread
1743 EVENT_THREAD_EXIT(this);
1744
1745 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1746 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1747 // is deprecated anyhow.
1748 { int count = 3;
1749 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1750 EXCEPTION_MARK;
1751 JavaValue result(T_VOID);
1752 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1753 JavaCalls::call_virtual(&result,
1754 threadObj, thread_klass,
1755 vmSymbols::exit_method_name(),
1756 vmSymbols::void_method_signature(),
1757 THREAD);
1758 CLEAR_PENDING_EXCEPTION;
1759 }
1760 }
1761
1762 // notify JVMTI
1763 if (JvmtiExport::should_post_thread_life()) {
1764 JvmtiExport::post_thread_end(this);
1765 }
1766
1767 // We have notified the agents that we are exiting, before we go on,
1768 // we must check for a pending external suspend request and honor it
1769 // in order to not surprise the thread that made the suspend request.
1770 while (true) {
1771 {
1772 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1773 if (!is_external_suspend()) {
1774 set_terminated(_thread_exiting);
1775 ThreadService::current_thread_exiting(this);
1776 break;
1777 }
1778 // Implied else:
1779 // Things get a little tricky here. We have a pending external
1780 // suspend request, but we are holding the SR_lock so we
1781 // can't just self-suspend. So we temporarily drop the lock
1782 // and then self-suspend.
1783 }
1784
1785 ThreadBlockInVM tbivm(this);
1786 java_suspend_self();
1787
1788 // We're done with this suspend request, but we have to loop around
1789 // and check again. Eventually we will get SR_lock without a pending
1790 // external suspend request and will be able to mark ourselves as
1791 // exiting.
1792 }
1793 // no more external suspends are allowed at this point
1794 } else {
1795 // before_exit() has already posted JVMTI THREAD_END events
1796 }
1797
1798 // Notify waiters on thread object. This has to be done after exit() is called
1799 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1800 // group should have the destroyed bit set before waiters are notified).
1801 ensure_join(this);
1802 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1803
1804 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1805 // held by this thread must be released. A detach operation must only
1806 // get here if there are no Java frames on the stack. Therefore, any
1807 // owned monitors at this point MUST be JNI-acquired monitors which are
1808 // pre-inflated and in the monitor cache.
1809 //
1810 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1811 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1812 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1813 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1814 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1815 }
1816
1817 // These things needs to be done while we are still a Java Thread. Make sure that thread
1818 // is in a consistent state, in case GC happens
1819 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1820
1821 if (active_handles() != NULL) {
1822 JNIHandleBlock* block = active_handles();
1823 set_active_handles(NULL);
1824 JNIHandleBlock::release_block(block);
1825 }
1826
1827 if (free_handle_block() != NULL) {
1828 JNIHandleBlock* block = free_handle_block();
1829 set_free_handle_block(NULL);
1830 JNIHandleBlock::release_block(block);
1831 }
1832
1833 // These have to be removed while this is still a valid thread.
1834 remove_stack_guard_pages();
1835
1836 if (UseTLAB) {
1837 tlab().make_parsable(true); // retire TLAB
1838 }
1839
1840 if (JvmtiEnv::environments_might_exist()) {
1841 JvmtiExport::cleanup_thread(this);
1842 }
1843
1844 #ifndef SERIALGC
1845 // We must flush G1-related buffers before removing a thread from
1846 // the list of active threads.
1847 if (UseG1GC) {
1848 flush_barrier_queues();
1849 }
1850 #endif
1851
1852 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1853 Threads::remove(this);
1854 }
1855
1856 #ifndef SERIALGC
1857 // Flush G1-related queues.
1858 void JavaThread::flush_barrier_queues() {
1859 satb_mark_queue().flush();
1860 dirty_card_queue().flush();
1861 }
1862
1863 void JavaThread::initialize_queues() {
1864 assert(!SafepointSynchronize::is_at_safepoint(),
1865 "we should not be at a safepoint");
1866
1867 ObjPtrQueue& satb_queue = satb_mark_queue();
1868 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1869 // The SATB queue should have been constructed with its active
1870 // field set to false.
1871 assert(!satb_queue.is_active(), "SATB queue should not be active");
1872 assert(satb_queue.is_empty(), "SATB queue should be empty");
1873 // If we are creating the thread during a marking cycle, we should
1874 // set the active field of the SATB queue to true.
1875 if (satb_queue_set.is_active()) {
1876 satb_queue.set_active(true);
1877 }
1878
1879 DirtyCardQueue& dirty_queue = dirty_card_queue();
1880 // The dirty card queue should have been constructed with its
1881 // active field set to true.
1882 assert(dirty_queue.is_active(), "dirty card queue should be active");
1883 }
1884 #endif // !SERIALGC
1885
1886 void JavaThread::cleanup_failed_attach_current_thread() {
1887 if (get_thread_profiler() != NULL) {
1888 get_thread_profiler()->disengage();
1889 ResourceMark rm;
1890 get_thread_profiler()->print(get_thread_name());
1891 }
1892
1893 if (active_handles() != NULL) {
1894 JNIHandleBlock* block = active_handles();
1895 set_active_handles(NULL);
1896 JNIHandleBlock::release_block(block);
1897 }
1898
1899 if (free_handle_block() != NULL) {
1900 JNIHandleBlock* block = free_handle_block();
1901 set_free_handle_block(NULL);
1902 JNIHandleBlock::release_block(block);
1903 }
1904
1905 // These have to be removed while this is still a valid thread.
1906 remove_stack_guard_pages();
1907
1908 if (UseTLAB) {
1909 tlab().make_parsable(true); // retire TLAB, if any
1910 }
1911
1912 #ifndef SERIALGC
1913 if (UseG1GC) {
1914 flush_barrier_queues();
1915 }
1916 #endif
1917
1918 Threads::remove(this);
1919 delete this;
1920 }
1921
1922
1923
1924
1925 JavaThread* JavaThread::active() {
1926 Thread* thread = ThreadLocalStorage::thread();
1927 assert(thread != NULL, "just checking");
1928 if (thread->is_Java_thread()) {
1929 return (JavaThread*) thread;
1930 } else {
1931 assert(thread->is_VM_thread(), "this must be a vm thread");
1932 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1933 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1934 assert(ret->is_Java_thread(), "must be a Java thread");
1935 return ret;
1936 }
1937 }
1938
1939 bool JavaThread::is_lock_owned(address adr) const {
1940 if (Thread::is_lock_owned(adr)) return true;
1941
1942 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1943 if (chunk->contains(adr)) return true;
1944 }
1945
1946 return false;
1947 }
1948
1949
1950 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1951 chunk->set_next(monitor_chunks());
1952 set_monitor_chunks(chunk);
1953 }
1954
1955 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1956 guarantee(monitor_chunks() != NULL, "must be non empty");
1957 if (monitor_chunks() == chunk) {
1958 set_monitor_chunks(chunk->next());
1959 } else {
1960 MonitorChunk* prev = monitor_chunks();
1961 while (prev->next() != chunk) prev = prev->next();
1962 prev->set_next(chunk->next());
1963 }
1964 }
1965
1966 // JVM support.
1967
1968 // Note: this function shouldn't block if it's called in
1969 // _thread_in_native_trans state (such as from
1970 // check_special_condition_for_native_trans()).
1971 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1972
1973 if (has_last_Java_frame() && has_async_condition()) {
1974 // If we are at a polling page safepoint (not a poll return)
1975 // then we must defer async exception because live registers
1976 // will be clobbered by the exception path. Poll return is
1977 // ok because the call we a returning from already collides
1978 // with exception handling registers and so there is no issue.
1979 // (The exception handling path kills call result registers but
1980 // this is ok since the exception kills the result anyway).
1981
1982 if (is_at_poll_safepoint()) {
1983 // if the code we are returning to has deoptimized we must defer
1984 // the exception otherwise live registers get clobbered on the
1985 // exception path before deoptimization is able to retrieve them.
1986 //
1987 RegisterMap map(this, false);
1988 frame caller_fr = last_frame().sender(&map);
1989 assert(caller_fr.is_compiled_frame(), "what?");
1990 if (caller_fr.is_deoptimized_frame()) {
1991 if (TraceExceptions) {
1992 ResourceMark rm;
1993 tty->print_cr("deferred async exception at compiled safepoint");
1994 }
1995 return;
1996 }
1997 }
1998 }
1999
2000 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2001 if (condition == _no_async_condition) {
2002 // Conditions have changed since has_special_runtime_exit_condition()
2003 // was called:
2004 // - if we were here only because of an external suspend request,
2005 // then that was taken care of above (or cancelled) so we are done
2006 // - if we were here because of another async request, then it has
2007 // been cleared between the has_special_runtime_exit_condition()
2008 // and now so again we are done
2009 return;
2010 }
2011
2012 // Check for pending async. exception
2013 if (_pending_async_exception != NULL) {
2014 // Only overwrite an already pending exception, if it is not a threadDeath.
2015 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2016
2017 // We cannot call Exceptions::_throw(...) here because we cannot block
2018 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2019
2020 if (TraceExceptions) {
2021 ResourceMark rm;
2022 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2023 if (has_last_Java_frame() ) {
2024 frame f = last_frame();
2025 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2026 }
2027 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
2028 }
2029 _pending_async_exception = NULL;
2030 clear_has_async_exception();
2031 }
2032 }
2033
2034 if (check_unsafe_error &&
2035 condition == _async_unsafe_access_error && !has_pending_exception()) {
2036 condition = _no_async_condition; // done
2037 switch (thread_state()) {
2038 case _thread_in_vm:
2039 {
2040 JavaThread* THREAD = this;
2041 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2042 }
2043 case _thread_in_native:
2044 {
2045 ThreadInVMfromNative tiv(this);
2046 JavaThread* THREAD = this;
2047 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2048 }
2049 case _thread_in_Java:
2050 {
2051 ThreadInVMfromJava tiv(this);
2052 JavaThread* THREAD = this;
2053 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2054 }
2055 default:
2056 ShouldNotReachHere();
2057 }
2058 }
2059
2060 assert(condition == _no_async_condition || has_pending_exception() ||
2061 (!check_unsafe_error && condition == _async_unsafe_access_error),
2062 "must have handled the async condition, if no exception");
2063 }
2064
2065 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2066 //
2067 // Check for pending external suspend. Internal suspend requests do
2068 // not use handle_special_runtime_exit_condition().
2069 // If JNIEnv proxies are allowed, don't self-suspend if the target
2070 // thread is not the current thread. In older versions of jdbx, jdbx
2071 // threads could call into the VM with another thread's JNIEnv so we
2072 // can be here operating on behalf of a suspended thread (4432884).
2073 bool do_self_suspend = is_external_suspend_with_lock();
2074 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2075 //
2076 // Because thread is external suspended the safepoint code will count
2077 // thread as at a safepoint. This can be odd because we can be here
2078 // as _thread_in_Java which would normally transition to _thread_blocked
2079 // at a safepoint. We would like to mark the thread as _thread_blocked
2080 // before calling java_suspend_self like all other callers of it but
2081 // we must then observe proper safepoint protocol. (We can't leave
2082 // _thread_blocked with a safepoint in progress). However we can be
2083 // here as _thread_in_native_trans so we can't use a normal transition
2084 // constructor/destructor pair because they assert on that type of
2085 // transition. We could do something like:
2086 //
2087 // JavaThreadState state = thread_state();
2088 // set_thread_state(_thread_in_vm);
2089 // {
2090 // ThreadBlockInVM tbivm(this);
2091 // java_suspend_self()
2092 // }
2093 // set_thread_state(_thread_in_vm_trans);
2094 // if (safepoint) block;
2095 // set_thread_state(state);
2096 //
2097 // but that is pretty messy. Instead we just go with the way the
2098 // code has worked before and note that this is the only path to
2099 // java_suspend_self that doesn't put the thread in _thread_blocked
2100 // mode.
2101
2102 frame_anchor()->make_walkable(this);
2103 java_suspend_self();
2104
2105 // We might be here for reasons in addition to the self-suspend request
2106 // so check for other async requests.
2107 }
2108
2109 if (check_asyncs) {
2110 check_and_handle_async_exceptions();
2111 }
2112 }
2113
2114 void JavaThread::send_thread_stop(oop java_throwable) {
2115 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2116 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2117 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2118
2119 // Do not throw asynchronous exceptions against the compiler thread
2120 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2121 if (is_Compiler_thread()) return;
2122
2123 {
2124 // Actually throw the Throwable against the target Thread - however
2125 // only if there is no thread death exception installed already.
2126 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2127 // If the topmost frame is a runtime stub, then we are calling into
2128 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2129 // must deoptimize the caller before continuing, as the compiled exception handler table
2130 // may not be valid
2131 if (has_last_Java_frame()) {
2132 frame f = last_frame();
2133 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2134 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2135 RegisterMap reg_map(this, UseBiasedLocking);
2136 frame compiled_frame = f.sender(®_map);
2137 if (compiled_frame.can_be_deoptimized()) {
2138 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2139 }
2140 }
2141 }
2142
2143 // Set async. pending exception in thread.
2144 set_pending_async_exception(java_throwable);
2145
2146 if (TraceExceptions) {
2147 ResourceMark rm;
2148 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
2149 }
2150 // for AbortVMOnException flag
2151 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
2152 }
2153 }
2154
2155
2156 // Interrupt thread so it will wake up from a potential wait()
2157 Thread::interrupt(this);
2158 }
2159
2160 // External suspension mechanism.
2161 //
2162 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2163 // to any VM_locks and it is at a transition
2164 // Self-suspension will happen on the transition out of the vm.
2165 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2166 //
2167 // Guarantees on return:
2168 // + Target thread will not execute any new bytecode (that's why we need to
2169 // force a safepoint)
2170 // + Target thread will not enter any new monitors
2171 //
2172 void JavaThread::java_suspend() {
2173 { MutexLocker mu(Threads_lock);
2174 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2175 return;
2176 }
2177 }
2178
2179 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2180 if (!is_external_suspend()) {
2181 // a racing resume has cancelled us; bail out now
2182 return;
2183 }
2184
2185 // suspend is done
2186 uint32_t debug_bits = 0;
2187 // Warning: is_ext_suspend_completed() may temporarily drop the
2188 // SR_lock to allow the thread to reach a stable thread state if
2189 // it is currently in a transient thread state.
2190 if (is_ext_suspend_completed(false /* !called_by_wait */,
2191 SuspendRetryDelay, &debug_bits) ) {
2192 return;
2193 }
2194 }
2195
2196 VM_ForceSafepoint vm_suspend;
2197 VMThread::execute(&vm_suspend);
2198 }
2199
2200 // Part II of external suspension.
2201 // A JavaThread self suspends when it detects a pending external suspend
2202 // request. This is usually on transitions. It is also done in places
2203 // where continuing to the next transition would surprise the caller,
2204 // e.g., monitor entry.
2205 //
2206 // Returns the number of times that the thread self-suspended.
2207 //
2208 // Note: DO NOT call java_suspend_self() when you just want to block current
2209 // thread. java_suspend_self() is the second stage of cooperative
2210 // suspension for external suspend requests and should only be used
2211 // to complete an external suspend request.
2212 //
2213 int JavaThread::java_suspend_self() {
2214 int ret = 0;
2215
2216 // we are in the process of exiting so don't suspend
2217 if (is_exiting()) {
2218 clear_external_suspend();
2219 return ret;
2220 }
2221
2222 assert(_anchor.walkable() ||
2223 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2224 "must have walkable stack");
2225
2226 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2227
2228 assert(!this->is_ext_suspended(),
2229 "a thread trying to self-suspend should not already be suspended");
2230
2231 if (this->is_suspend_equivalent()) {
2232 // If we are self-suspending as a result of the lifting of a
2233 // suspend equivalent condition, then the suspend_equivalent
2234 // flag is not cleared until we set the ext_suspended flag so
2235 // that wait_for_ext_suspend_completion() returns consistent
2236 // results.
2237 this->clear_suspend_equivalent();
2238 }
2239
2240 // A racing resume may have cancelled us before we grabbed SR_lock
2241 // above. Or another external suspend request could be waiting for us
2242 // by the time we return from SR_lock()->wait(). The thread
2243 // that requested the suspension may already be trying to walk our
2244 // stack and if we return now, we can change the stack out from under
2245 // it. This would be a "bad thing (TM)" and cause the stack walker
2246 // to crash. We stay self-suspended until there are no more pending
2247 // external suspend requests.
2248 while (is_external_suspend()) {
2249 ret++;
2250 this->set_ext_suspended();
2251
2252 // _ext_suspended flag is cleared by java_resume()
2253 while (is_ext_suspended()) {
2254 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2255 }
2256 }
2257
2258 return ret;
2259 }
2260
2261 #ifdef ASSERT
2262 // verify the JavaThread has not yet been published in the Threads::list, and
2263 // hence doesn't need protection from concurrent access at this stage
2264 void JavaThread::verify_not_published() {
2265 if (!Threads_lock->owned_by_self()) {
2266 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2267 assert( !Threads::includes(this),
2268 "java thread shouldn't have been published yet!");
2269 }
2270 else {
2271 assert( !Threads::includes(this),
2272 "java thread shouldn't have been published yet!");
2273 }
2274 }
2275 #endif
2276
2277 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2278 // progress or when _suspend_flags is non-zero.
2279 // Current thread needs to self-suspend if there is a suspend request and/or
2280 // block if a safepoint is in progress.
2281 // Async exception ISN'T checked.
2282 // Note only the ThreadInVMfromNative transition can call this function
2283 // directly and when thread state is _thread_in_native_trans
2284 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2285 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2286
2287 JavaThread *curJT = JavaThread::current();
2288 bool do_self_suspend = thread->is_external_suspend();
2289
2290 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2291
2292 // If JNIEnv proxies are allowed, don't self-suspend if the target
2293 // thread is not the current thread. In older versions of jdbx, jdbx
2294 // threads could call into the VM with another thread's JNIEnv so we
2295 // can be here operating on behalf of a suspended thread (4432884).
2296 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2297 JavaThreadState state = thread->thread_state();
2298
2299 // We mark this thread_blocked state as a suspend-equivalent so
2300 // that a caller to is_ext_suspend_completed() won't be confused.
2301 // The suspend-equivalent state is cleared by java_suspend_self().
2302 thread->set_suspend_equivalent();
2303
2304 // If the safepoint code sees the _thread_in_native_trans state, it will
2305 // wait until the thread changes to other thread state. There is no
2306 // guarantee on how soon we can obtain the SR_lock and complete the
2307 // self-suspend request. It would be a bad idea to let safepoint wait for
2308 // too long. Temporarily change the state to _thread_blocked to
2309 // let the VM thread know that this thread is ready for GC. The problem
2310 // of changing thread state is that safepoint could happen just after
2311 // java_suspend_self() returns after being resumed, and VM thread will
2312 // see the _thread_blocked state. We must check for safepoint
2313 // after restoring the state and make sure we won't leave while a safepoint
2314 // is in progress.
2315 thread->set_thread_state(_thread_blocked);
2316 thread->java_suspend_self();
2317 thread->set_thread_state(state);
2318 // Make sure new state is seen by VM thread
2319 if (os::is_MP()) {
2320 if (UseMembar) {
2321 // Force a fence between the write above and read below
2322 OrderAccess::fence();
2323 } else {
2324 // Must use this rather than serialization page in particular on Windows
2325 InterfaceSupport::serialize_memory(thread);
2326 }
2327 }
2328 }
2329
2330 if (SafepointSynchronize::do_call_back()) {
2331 // If we are safepointing, then block the caller which may not be
2332 // the same as the target thread (see above).
2333 SafepointSynchronize::block(curJT);
2334 }
2335
2336 if (thread->is_deopt_suspend()) {
2337 thread->clear_deopt_suspend();
2338 RegisterMap map(thread, false);
2339 frame f = thread->last_frame();
2340 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2341 f = f.sender(&map);
2342 }
2343 if (f.id() == thread->must_deopt_id()) {
2344 thread->clear_must_deopt_id();
2345 f.deoptimize(thread);
2346 } else {
2347 fatal("missed deoptimization!");
2348 }
2349 }
2350 }
2351
2352 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2353 // progress or when _suspend_flags is non-zero.
2354 // Current thread needs to self-suspend if there is a suspend request and/or
2355 // block if a safepoint is in progress.
2356 // Also check for pending async exception (not including unsafe access error).
2357 // Note only the native==>VM/Java barriers can call this function and when
2358 // thread state is _thread_in_native_trans.
2359 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2360 check_safepoint_and_suspend_for_native_trans(thread);
2361
2362 if (thread->has_async_exception()) {
2363 // We are in _thread_in_native_trans state, don't handle unsafe
2364 // access error since that may block.
2365 thread->check_and_handle_async_exceptions(false);
2366 }
2367 }
2368
2369 // This is a variant of the normal
2370 // check_special_condition_for_native_trans with slightly different
2371 // semantics for use by critical native wrappers. It does all the
2372 // normal checks but also performs the transition back into
2373 // thread_in_Java state. This is required so that critical natives
2374 // can potentially block and perform a GC if they are the last thread
2375 // exiting the GC_locker.
2376 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2377 check_special_condition_for_native_trans(thread);
2378
2379 // Finish the transition
2380 thread->set_thread_state(_thread_in_Java);
2381
2382 if (thread->do_critical_native_unlock()) {
2383 ThreadInVMfromJavaNoAsyncException tiv(thread);
2384 GC_locker::unlock_critical(thread);
2385 thread->clear_critical_native_unlock();
2386 }
2387 }
2388
2389 // We need to guarantee the Threads_lock here, since resumes are not
2390 // allowed during safepoint synchronization
2391 // Can only resume from an external suspension
2392 void JavaThread::java_resume() {
2393 assert_locked_or_safepoint(Threads_lock);
2394
2395 // Sanity check: thread is gone, has started exiting or the thread
2396 // was not externally suspended.
2397 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2398 return;
2399 }
2400
2401 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2402
2403 clear_external_suspend();
2404
2405 if (is_ext_suspended()) {
2406 clear_ext_suspended();
2407 SR_lock()->notify_all();
2408 }
2409 }
2410
2411 void JavaThread::create_stack_guard_pages() {
2412 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2413 address low_addr = stack_base() - stack_size();
2414 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2415
2416 int allocate = os::allocate_stack_guard_pages();
2417 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2418
2419 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2420 warning("Attempt to allocate stack guard pages failed.");
2421 return;
2422 }
2423
2424 if (os::guard_memory((char *) low_addr, len)) {
2425 _stack_guard_state = stack_guard_enabled;
2426 } else {
2427 warning("Attempt to protect stack guard pages failed.");
2428 if (os::uncommit_memory((char *) low_addr, len)) {
2429 warning("Attempt to deallocate stack guard pages failed.");
2430 }
2431 }
2432 }
2433
2434 void JavaThread::remove_stack_guard_pages() {
2435 if (_stack_guard_state == stack_guard_unused) return;
2436 address low_addr = stack_base() - stack_size();
2437 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2438
2439 if (os::allocate_stack_guard_pages()) {
2440 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2441 _stack_guard_state = stack_guard_unused;
2442 } else {
2443 warning("Attempt to deallocate stack guard pages failed.");
2444 }
2445 } else {
2446 if (_stack_guard_state == stack_guard_unused) return;
2447 if (os::unguard_memory((char *) low_addr, len)) {
2448 _stack_guard_state = stack_guard_unused;
2449 } else {
2450 warning("Attempt to unprotect stack guard pages failed.");
2451 }
2452 }
2453 }
2454
2455 void JavaThread::enable_stack_yellow_zone() {
2456 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2457 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2458
2459 // The base notation is from the stacks point of view, growing downward.
2460 // We need to adjust it to work correctly with guard_memory()
2461 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2462
2463 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2464 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2465
2466 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2467 _stack_guard_state = stack_guard_enabled;
2468 } else {
2469 warning("Attempt to guard stack yellow zone failed.");
2470 }
2471 enable_register_stack_guard();
2472 }
2473
2474 void JavaThread::disable_stack_yellow_zone() {
2475 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2476 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2477
2478 // Simply return if called for a thread that does not use guard pages.
2479 if (_stack_guard_state == stack_guard_unused) return;
2480
2481 // The base notation is from the stacks point of view, growing downward.
2482 // We need to adjust it to work correctly with guard_memory()
2483 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2484
2485 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2486 _stack_guard_state = stack_guard_yellow_disabled;
2487 } else {
2488 warning("Attempt to unguard stack yellow zone failed.");
2489 }
2490 disable_register_stack_guard();
2491 }
2492
2493 void JavaThread::enable_stack_red_zone() {
2494 // The base notation is from the stacks point of view, growing downward.
2495 // We need to adjust it to work correctly with guard_memory()
2496 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2497 address base = stack_red_zone_base() - stack_red_zone_size();
2498
2499 guarantee(base < stack_base(),"Error calculating stack red zone");
2500 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2501
2502 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2503 warning("Attempt to guard stack red zone failed.");
2504 }
2505 }
2506
2507 void JavaThread::disable_stack_red_zone() {
2508 // The base notation is from the stacks point of view, growing downward.
2509 // We need to adjust it to work correctly with guard_memory()
2510 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2511 address base = stack_red_zone_base() - stack_red_zone_size();
2512 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2513 warning("Attempt to unguard stack red zone failed.");
2514 }
2515 }
2516
2517 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2518 // ignore is there is no stack
2519 if (!has_last_Java_frame()) return;
2520 // traverse the stack frames. Starts from top frame.
2521 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2522 frame* fr = fst.current();
2523 f(fr, fst.register_map());
2524 }
2525 }
2526
2527
2528 #ifndef PRODUCT
2529 // Deoptimization
2530 // Function for testing deoptimization
2531 void JavaThread::deoptimize() {
2532 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2533 StackFrameStream fst(this, UseBiasedLocking);
2534 bool deopt = false; // Dump stack only if a deopt actually happens.
2535 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2536 // Iterate over all frames in the thread and deoptimize
2537 for(; !fst.is_done(); fst.next()) {
2538 if(fst.current()->can_be_deoptimized()) {
2539
2540 if (only_at) {
2541 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2542 // consists of comma or carriage return separated numbers so
2543 // search for the current bci in that string.
2544 address pc = fst.current()->pc();
2545 nmethod* nm = (nmethod*) fst.current()->cb();
2546 ScopeDesc* sd = nm->scope_desc_at( pc);
2547 char buffer[8];
2548 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2549 size_t len = strlen(buffer);
2550 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2551 while (found != NULL) {
2552 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2553 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2554 // Check that the bci found is bracketed by terminators.
2555 break;
2556 }
2557 found = strstr(found + 1, buffer);
2558 }
2559 if (!found) {
2560 continue;
2561 }
2562 }
2563
2564 if (DebugDeoptimization && !deopt) {
2565 deopt = true; // One-time only print before deopt
2566 tty->print_cr("[BEFORE Deoptimization]");
2567 trace_frames();
2568 trace_stack();
2569 }
2570 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2571 }
2572 }
2573
2574 if (DebugDeoptimization && deopt) {
2575 tty->print_cr("[AFTER Deoptimization]");
2576 trace_frames();
2577 }
2578 }
2579
2580
2581 // Make zombies
2582 void JavaThread::make_zombies() {
2583 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2584 if (fst.current()->can_be_deoptimized()) {
2585 // it is a Java nmethod
2586 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2587 nm->make_not_entrant();
2588 }
2589 }
2590 }
2591 #endif // PRODUCT
2592
2593
2594 void JavaThread::deoptimized_wrt_marked_nmethods() {
2595 if (!has_last_Java_frame()) return;
2596 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2597 StackFrameStream fst(this, UseBiasedLocking);
2598 for(; !fst.is_done(); fst.next()) {
2599 if (fst.current()->should_be_deoptimized()) {
2600 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2601 }
2602 }
2603 }
2604
2605
2606 // GC support
2607 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2608
2609 void JavaThread::gc_epilogue() {
2610 frames_do(frame_gc_epilogue);
2611 }
2612
2613
2614 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2615
2616 void JavaThread::gc_prologue() {
2617 frames_do(frame_gc_prologue);
2618 }
2619
2620 // If the caller is a NamedThread, then remember, in the current scope,
2621 // the given JavaThread in its _processed_thread field.
2622 class RememberProcessedThread: public StackObj {
2623 NamedThread* _cur_thr;
2624 public:
2625 RememberProcessedThread(JavaThread* jthr) {
2626 Thread* thread = Thread::current();
2627 if (thread->is_Named_thread()) {
2628 _cur_thr = (NamedThread *)thread;
2629 _cur_thr->set_processed_thread(jthr);
2630 } else {
2631 _cur_thr = NULL;
2632 }
2633 }
2634
2635 ~RememberProcessedThread() {
2636 if (_cur_thr) {
2637 _cur_thr->set_processed_thread(NULL);
2638 }
2639 }
2640 };
2641
2642 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2643 // Verify that the deferred card marks have been flushed.
2644 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2645
2646 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2647 // since there may be more than one thread using each ThreadProfiler.
2648
2649 // Traverse the GCHandles
2650 Thread::oops_do(f, cf);
2651
2652 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2653 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2654
2655 if (has_last_Java_frame()) {
2656 // Record JavaThread to GC thread
2657 RememberProcessedThread rpt(this);
2658
2659 // Traverse the privileged stack
2660 if (_privileged_stack_top != NULL) {
2661 _privileged_stack_top->oops_do(f);
2662 }
2663
2664 // traverse the registered growable array
2665 if (_array_for_gc != NULL) {
2666 for (int index = 0; index < _array_for_gc->length(); index++) {
2667 f->do_oop(_array_for_gc->adr_at(index));
2668 }
2669 }
2670
2671 // Traverse the monitor chunks
2672 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2673 chunk->oops_do(f);
2674 }
2675
2676 // Traverse the execution stack
2677 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2678 fst.current()->oops_do(f, cf, fst.register_map());
2679 }
2680 }
2681
2682 // callee_target is never live across a gc point so NULL it here should
2683 // it still contain a methdOop.
2684
2685 set_callee_target(NULL);
2686
2687 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2688 // If we have deferred set_locals there might be oops waiting to be
2689 // written
2690 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2691 if (list != NULL) {
2692 for (int i = 0; i < list->length(); i++) {
2693 list->at(i)->oops_do(f);
2694 }
2695 }
2696
2697 // Traverse instance variables at the end since the GC may be moving things
2698 // around using this function
2699 f->do_oop((oop*) &_threadObj);
2700 f->do_oop((oop*) &_vm_result);
2701 f->do_oop((oop*) &_vm_result_2);
2702 f->do_oop((oop*) &_exception_oop);
2703 f->do_oop((oop*) &_pending_async_exception);
2704
2705 if (jvmti_thread_state() != NULL) {
2706 jvmti_thread_state()->oops_do(f);
2707 }
2708 }
2709
2710 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2711 Thread::nmethods_do(cf); // (super method is a no-op)
2712
2713 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2714 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2715
2716 if (has_last_Java_frame()) {
2717 // Traverse the execution stack
2718 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2719 fst.current()->nmethods_do(cf);
2720 }
2721 }
2722 }
2723
2724 // Printing
2725 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2726 switch (_thread_state) {
2727 case _thread_uninitialized: return "_thread_uninitialized";
2728 case _thread_new: return "_thread_new";
2729 case _thread_new_trans: return "_thread_new_trans";
2730 case _thread_in_native: return "_thread_in_native";
2731 case _thread_in_native_trans: return "_thread_in_native_trans";
2732 case _thread_in_vm: return "_thread_in_vm";
2733 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2734 case _thread_in_Java: return "_thread_in_Java";
2735 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2736 case _thread_blocked: return "_thread_blocked";
2737 case _thread_blocked_trans: return "_thread_blocked_trans";
2738 default: return "unknown thread state";
2739 }
2740 }
2741
2742 #ifndef PRODUCT
2743 void JavaThread::print_thread_state_on(outputStream *st) const {
2744 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2745 };
2746 void JavaThread::print_thread_state() const {
2747 print_thread_state_on(tty);
2748 };
2749 #endif // PRODUCT
2750
2751 // Called by Threads::print() for VM_PrintThreads operation
2752 void JavaThread::print_on(outputStream *st) const {
2753 st->print("\"%s\" ", get_thread_name());
2754 oop thread_oop = threadObj();
2755 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2756 Thread::print_on(st);
2757 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2758 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2759 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2760 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2761 }
2762 #ifndef PRODUCT
2763 print_thread_state_on(st);
2764 _safepoint_state->print_on(st);
2765 #endif // PRODUCT
2766 }
2767
2768 // Called by fatal error handler. The difference between this and
2769 // JavaThread::print() is that we can't grab lock or allocate memory.
2770 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2771 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2772 oop thread_obj = threadObj();
2773 if (thread_obj != NULL) {
2774 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2775 }
2776 st->print(" [");
2777 st->print("%s", _get_thread_state_name(_thread_state));
2778 if (osthread()) {
2779 st->print(", id=%d", osthread()->thread_id());
2780 }
2781 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2782 _stack_base - _stack_size, _stack_base);
2783 st->print("]");
2784 return;
2785 }
2786
2787 // Verification
2788
2789 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2790
2791 void JavaThread::verify() {
2792 // Verify oops in the thread.
2793 oops_do(&VerifyOopClosure::verify_oop, NULL);
2794
2795 // Verify the stack frames.
2796 frames_do(frame_verify);
2797 }
2798
2799 // CR 6300358 (sub-CR 2137150)
2800 // Most callers of this method assume that it can't return NULL but a
2801 // thread may not have a name whilst it is in the process of attaching to
2802 // the VM - see CR 6412693, and there are places where a JavaThread can be
2803 // seen prior to having it's threadObj set (eg JNI attaching threads and
2804 // if vm exit occurs during initialization). These cases can all be accounted
2805 // for such that this method never returns NULL.
2806 const char* JavaThread::get_thread_name() const {
2807 #ifdef ASSERT
2808 // early safepoints can hit while current thread does not yet have TLS
2809 if (!SafepointSynchronize::is_at_safepoint()) {
2810 Thread *cur = Thread::current();
2811 if (!(cur->is_Java_thread() && cur == this)) {
2812 // Current JavaThreads are allowed to get their own name without
2813 // the Threads_lock.
2814 assert_locked_or_safepoint(Threads_lock);
2815 }
2816 }
2817 #endif // ASSERT
2818 return get_thread_name_string();
2819 }
2820
2821 // Returns a non-NULL representation of this thread's name, or a suitable
2822 // descriptive string if there is no set name
2823 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2824 const char* name_str;
2825 oop thread_obj = threadObj();
2826 if (thread_obj != NULL) {
2827 typeArrayOop name = java_lang_Thread::name(thread_obj);
2828 if (name != NULL) {
2829 if (buf == NULL) {
2830 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2831 }
2832 else {
2833 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2834 }
2835 }
2836 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2837 name_str = "<no-name - thread is attaching>";
2838 }
2839 else {
2840 name_str = Thread::name();
2841 }
2842 }
2843 else {
2844 name_str = Thread::name();
2845 }
2846 assert(name_str != NULL, "unexpected NULL thread name");
2847 return name_str;
2848 }
2849
2850
2851 const char* JavaThread::get_threadgroup_name() const {
2852 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2853 oop thread_obj = threadObj();
2854 if (thread_obj != NULL) {
2855 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2856 if (thread_group != NULL) {
2857 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2858 // ThreadGroup.name can be null
2859 if (name != NULL) {
2860 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2861 return str;
2862 }
2863 }
2864 }
2865 return NULL;
2866 }
2867
2868 const char* JavaThread::get_parent_name() const {
2869 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2870 oop thread_obj = threadObj();
2871 if (thread_obj != NULL) {
2872 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2873 if (thread_group != NULL) {
2874 oop parent = java_lang_ThreadGroup::parent(thread_group);
2875 if (parent != NULL) {
2876 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2877 // ThreadGroup.name can be null
2878 if (name != NULL) {
2879 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2880 return str;
2881 }
2882 }
2883 }
2884 }
2885 return NULL;
2886 }
2887
2888 ThreadPriority JavaThread::java_priority() const {
2889 oop thr_oop = threadObj();
2890 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2891 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2892 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2893 return priority;
2894 }
2895
2896 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2897
2898 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2899 // Link Java Thread object <-> C++ Thread
2900
2901 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2902 // and put it into a new Handle. The Handle "thread_oop" can then
2903 // be used to pass the C++ thread object to other methods.
2904
2905 // Set the Java level thread object (jthread) field of the
2906 // new thread (a JavaThread *) to C++ thread object using the
2907 // "thread_oop" handle.
2908
2909 // Set the thread field (a JavaThread *) of the
2910 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2911
2912 Handle thread_oop(Thread::current(),
2913 JNIHandles::resolve_non_null(jni_thread));
2914 assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
2915 "must be initialized");
2916 set_threadObj(thread_oop());
2917 java_lang_Thread::set_thread(thread_oop(), this);
2918
2919 if (prio == NoPriority) {
2920 prio = java_lang_Thread::priority(thread_oop());
2921 assert(prio != NoPriority, "A valid priority should be present");
2922 }
2923
2924 // Push the Java priority down to the native thread; needs Threads_lock
2925 Thread::set_priority(this, prio);
2926
2927 // Add the new thread to the Threads list and set it in motion.
2928 // We must have threads lock in order to call Threads::add.
2929 // It is crucial that we do not block before the thread is
2930 // added to the Threads list for if a GC happens, then the java_thread oop
2931 // will not be visited by GC.
2932 Threads::add(this);
2933 }
2934
2935 oop JavaThread::current_park_blocker() {
2936 // Support for JSR-166 locks
2937 oop thread_oop = threadObj();
2938 if (thread_oop != NULL &&
2939 JDK_Version::current().supports_thread_park_blocker()) {
2940 return java_lang_Thread::park_blocker(thread_oop);
2941 }
2942 return NULL;
2943 }
2944
2945
2946 void JavaThread::print_stack_on(outputStream* st) {
2947 if (!has_last_Java_frame()) return;
2948 ResourceMark rm;
2949 HandleMark hm;
2950
2951 RegisterMap reg_map(this);
2952 vframe* start_vf = last_java_vframe(®_map);
2953 int count = 0;
2954 for (vframe* f = start_vf; f; f = f->sender() ) {
2955 if (f->is_java_frame()) {
2956 javaVFrame* jvf = javaVFrame::cast(f);
2957 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2958
2959 // Print out lock information
2960 if (JavaMonitorsInStackTrace) {
2961 jvf->print_lock_info_on(st, count);
2962 }
2963 } else {
2964 // Ignore non-Java frames
2965 }
2966
2967 // Bail-out case for too deep stacks
2968 count++;
2969 if (MaxJavaStackTraceDepth == count) return;
2970 }
2971 }
2972
2973
2974 // JVMTI PopFrame support
2975 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2976 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2977 if (in_bytes(size_in_bytes) != 0) {
2978 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
2979 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2980 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2981 }
2982 }
2983
2984 void* JavaThread::popframe_preserved_args() {
2985 return _popframe_preserved_args;
2986 }
2987
2988 ByteSize JavaThread::popframe_preserved_args_size() {
2989 return in_ByteSize(_popframe_preserved_args_size);
2990 }
2991
2992 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2993 int sz = in_bytes(popframe_preserved_args_size());
2994 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2995 return in_WordSize(sz / wordSize);
2996 }
2997
2998 void JavaThread::popframe_free_preserved_args() {
2999 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3000 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3001 _popframe_preserved_args = NULL;
3002 _popframe_preserved_args_size = 0;
3003 }
3004
3005 #ifndef PRODUCT
3006
3007 void JavaThread::trace_frames() {
3008 tty->print_cr("[Describe stack]");
3009 int frame_no = 1;
3010 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3011 tty->print(" %d. ", frame_no++);
3012 fst.current()->print_value_on(tty,this);
3013 tty->cr();
3014 }
3015 }
3016
3017 class PrintAndVerifyOopClosure: public OopClosure {
3018 protected:
3019 template <class T> inline void do_oop_work(T* p) {
3020 oop obj = oopDesc::load_decode_heap_oop(p);
3021 if (obj == NULL) return;
3022 tty->print(INTPTR_FORMAT ": ", p);
3023 if (obj->is_oop_or_null()) {
3024 if (obj->is_objArray()) {
3025 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3026 } else {
3027 obj->print();
3028 }
3029 } else {
3030 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3031 }
3032 tty->cr();
3033 }
3034 public:
3035 virtual void do_oop(oop* p) { do_oop_work(p); }
3036 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3037 };
3038
3039
3040 static void oops_print(frame* f, const RegisterMap *map) {
3041 PrintAndVerifyOopClosure print;
3042 f->print_value();
3043 f->oops_do(&print, NULL, (RegisterMap*)map);
3044 }
3045
3046 // Print our all the locations that contain oops and whether they are
3047 // valid or not. This useful when trying to find the oldest frame
3048 // where an oop has gone bad since the frame walk is from youngest to
3049 // oldest.
3050 void JavaThread::trace_oops() {
3051 tty->print_cr("[Trace oops]");
3052 frames_do(oops_print);
3053 }
3054
3055
3056 #ifdef ASSERT
3057 // Print or validate the layout of stack frames
3058 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3059 ResourceMark rm;
3060 PRESERVE_EXCEPTION_MARK;
3061 FrameValues values;
3062 int frame_no = 0;
3063 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3064 fst.current()->describe(values, ++frame_no);
3065 if (depth == frame_no) break;
3066 }
3067 if (validate_only) {
3068 values.validate();
3069 } else {
3070 tty->print_cr("[Describe stack layout]");
3071 values.print(this);
3072 }
3073 }
3074 #endif
3075
3076 void JavaThread::trace_stack_from(vframe* start_vf) {
3077 ResourceMark rm;
3078 int vframe_no = 1;
3079 for (vframe* f = start_vf; f; f = f->sender() ) {
3080 if (f->is_java_frame()) {
3081 javaVFrame::cast(f)->print_activation(vframe_no++);
3082 } else {
3083 f->print();
3084 }
3085 if (vframe_no > StackPrintLimit) {
3086 tty->print_cr("...<more frames>...");
3087 return;
3088 }
3089 }
3090 }
3091
3092
3093 void JavaThread::trace_stack() {
3094 if (!has_last_Java_frame()) return;
3095 ResourceMark rm;
3096 HandleMark hm;
3097 RegisterMap reg_map(this);
3098 trace_stack_from(last_java_vframe(®_map));
3099 }
3100
3101
3102 #endif // PRODUCT
3103
3104
3105 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3106 assert(reg_map != NULL, "a map must be given");
3107 frame f = last_frame();
3108 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3109 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3110 }
3111 return NULL;
3112 }
3113
3114
3115 klassOop JavaThread::security_get_caller_class(int depth) {
3116 vframeStream vfst(this);
3117 vfst.security_get_caller_frame(depth);
3118 if (!vfst.at_end()) {
3119 return vfst.method()->method_holder();
3120 }
3121 return NULL;
3122 }
3123
3124 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3125 assert(thread->is_Compiler_thread(), "must be compiler thread");
3126 CompileBroker::compiler_thread_loop();
3127 }
3128
3129 // Create a CompilerThread
3130 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3131 : JavaThread(&compiler_thread_entry) {
3132 _env = NULL;
3133 _log = NULL;
3134 _task = NULL;
3135 _queue = queue;
3136 _counters = counters;
3137 _buffer_blob = NULL;
3138 _scanned_nmethod = NULL;
3139
3140 #ifndef PRODUCT
3141 _ideal_graph_printer = NULL;
3142 #endif
3143 }
3144
3145 void CompilerThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3146 JavaThread::oops_do(f, cf);
3147 if (_scanned_nmethod != NULL && cf != NULL) {
3148 // Safepoints can occur when the sweeper is scanning an nmethod so
3149 // process it here to make sure it isn't unloaded in the middle of
3150 // a scan.
3151 cf->do_code_blob(_scanned_nmethod);
3152 }
3153 }
3154
3155 // ======= Threads ========
3156
3157 // The Threads class links together all active threads, and provides
3158 // operations over all threads. It is protected by its own Mutex
3159 // lock, which is also used in other contexts to protect thread
3160 // operations from having the thread being operated on from exiting
3161 // and going away unexpectedly (e.g., safepoint synchronization)
3162
3163 JavaThread* Threads::_thread_list = NULL;
3164 int Threads::_number_of_threads = 0;
3165 int Threads::_number_of_non_daemon_threads = 0;
3166 int Threads::_return_code = 0;
3167 size_t JavaThread::_stack_size_at_create = 0;
3168
3169 // All JavaThreads
3170 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3171
3172 void os_stream();
3173
3174 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3175 void Threads::threads_do(ThreadClosure* tc) {
3176 assert_locked_or_safepoint(Threads_lock);
3177 // ALL_JAVA_THREADS iterates through all JavaThreads
3178 ALL_JAVA_THREADS(p) {
3179 tc->do_thread(p);
3180 }
3181 // Someday we could have a table or list of all non-JavaThreads.
3182 // For now, just manually iterate through them.
3183 tc->do_thread(VMThread::vm_thread());
3184 Universe::heap()->gc_threads_do(tc);
3185 WatcherThread *wt = WatcherThread::watcher_thread();
3186 // Strictly speaking, the following NULL check isn't sufficient to make sure
3187 // the data for WatcherThread is still valid upon being examined. However,
3188 // considering that WatchThread terminates when the VM is on the way to
3189 // exit at safepoint, the chance of the above is extremely small. The right
3190 // way to prevent termination of WatcherThread would be to acquire
3191 // Terminator_lock, but we can't do that without violating the lock rank
3192 // checking in some cases.
3193 if (wt != NULL)
3194 tc->do_thread(wt);
3195
3196 // If CompilerThreads ever become non-JavaThreads, add them here
3197 }
3198
3199 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3200
3201 extern void JDK_Version_init();
3202
3203 // Check version
3204 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3205
3206 // Initialize the output stream module
3207 ostream_init();
3208
3209 // Process java launcher properties.
3210 Arguments::process_sun_java_launcher_properties(args);
3211
3212 // Initialize the os module before using TLS
3213 os::init();
3214
3215 // Initialize system properties.
3216 Arguments::init_system_properties();
3217
3218 // So that JDK version can be used as a discrimintor when parsing arguments
3219 JDK_Version_init();
3220
3221 // Update/Initialize System properties after JDK version number is known
3222 Arguments::init_version_specific_system_properties();
3223
3224 // Parse arguments
3225 jint parse_result = Arguments::parse(args);
3226 if (parse_result != JNI_OK) return parse_result;
3227
3228 if (PauseAtStartup) {
3229 os::pause();
3230 }
3231
3232 #ifndef USDT2
3233 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3234 #else /* USDT2 */
3235 HOTSPOT_VM_INIT_BEGIN();
3236 #endif /* USDT2 */
3237
3238 // Record VM creation timing statistics
3239 TraceVmCreationTime create_vm_timer;
3240 create_vm_timer.start();
3241
3242 // Timing (must come after argument parsing)
3243 TraceTime timer("Create VM", TraceStartupTime);
3244
3245 // Initialize the os module after parsing the args
3246 jint os_init_2_result = os::init_2();
3247 if (os_init_2_result != JNI_OK) return os_init_2_result;
3248
3249 // intialize TLS
3250 ThreadLocalStorage::init();
3251
3252 // Bootstrap native memory tracking, so it can start recording memory
3253 // activities before worker thread is started. This is the first phase
3254 // of bootstrapping, VM is currently running in single-thread mode.
3255 MemTracker::bootstrap_single_thread();
3256
3257 // Initialize output stream logging
3258 ostream_init_log();
3259
3260 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3261 // Must be before create_vm_init_agents()
3262 if (Arguments::init_libraries_at_startup()) {
3263 convert_vm_init_libraries_to_agents();
3264 }
3265
3266 // Launch -agentlib/-agentpath and converted -Xrun agents
3267 if (Arguments::init_agents_at_startup()) {
3268 create_vm_init_agents();
3269 }
3270
3271 // Initialize Threads state
3272 _thread_list = NULL;
3273 _number_of_threads = 0;
3274 _number_of_non_daemon_threads = 0;
3275
3276 // Initialize global data structures and create system classes in heap
3277 vm_init_globals();
3278
3279 // Attach the main thread to this os thread
3280 JavaThread* main_thread = new JavaThread();
3281 main_thread->set_thread_state(_thread_in_vm);
3282 // must do this before set_active_handles and initialize_thread_local_storage
3283 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3284 // change the stack size recorded here to one based on the java thread
3285 // stacksize. This adjusted size is what is used to figure the placement
3286 // of the guard pages.
3287 main_thread->record_stack_base_and_size();
3288 main_thread->initialize_thread_local_storage();
3289
3290 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3291
3292 if (!main_thread->set_as_starting_thread()) {
3293 vm_shutdown_during_initialization(
3294 "Failed necessary internal allocation. Out of swap space");
3295 delete main_thread;
3296 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3297 return JNI_ENOMEM;
3298 }
3299
3300 // Enable guard page *after* os::create_main_thread(), otherwise it would
3301 // crash Linux VM, see notes in os_linux.cpp.
3302 main_thread->create_stack_guard_pages();
3303
3304 // Initialize Java-Level synchronization subsystem
3305 ObjectMonitor::Initialize() ;
3306
3307 // Second phase of bootstrapping, VM is about entering multi-thread mode
3308 MemTracker::bootstrap_multi_thread();
3309
3310 // Initialize global modules
3311 jint status = init_globals();
3312 if (status != JNI_OK) {
3313 delete main_thread;
3314 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3315 return status;
3316 }
3317
3318 // Should be done after the heap is fully created
3319 main_thread->cache_global_variables();
3320
3321 HandleMark hm;
3322
3323 { MutexLocker mu(Threads_lock);
3324 Threads::add(main_thread);
3325 }
3326
3327 // Any JVMTI raw monitors entered in onload will transition into
3328 // real raw monitor. VM is setup enough here for raw monitor enter.
3329 JvmtiExport::transition_pending_onload_raw_monitors();
3330
3331 if (VerifyBeforeGC &&
3332 Universe::heap()->total_collections() >= VerifyGCStartAt) {
3333 Universe::heap()->prepare_for_verify();
3334 Universe::verify(); // make sure we're starting with a clean slate
3335 }
3336
3337 // Fully start NMT
3338 MemTracker::start();
3339
3340 // Create the VMThread
3341 { TraceTime timer("Start VMThread", TraceStartupTime);
3342 VMThread::create();
3343 Thread* vmthread = VMThread::vm_thread();
3344
3345 if (!os::create_thread(vmthread, os::vm_thread))
3346 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3347
3348 // Wait for the VM thread to become ready, and VMThread::run to initialize
3349 // Monitors can have spurious returns, must always check another state flag
3350 {
3351 MutexLocker ml(Notify_lock);
3352 os::start_thread(vmthread);
3353 while (vmthread->active_handles() == NULL) {
3354 Notify_lock->wait();
3355 }
3356 }
3357 }
3358
3359 assert (Universe::is_fully_initialized(), "not initialized");
3360 EXCEPTION_MARK;
3361
3362 // At this point, the Universe is initialized, but we have not executed
3363 // any byte code. Now is a good time (the only time) to dump out the
3364 // internal state of the JVM for sharing.
3365
3366 if (DumpSharedSpaces) {
3367 Universe::heap()->preload_and_dump(CHECK_0);
3368 ShouldNotReachHere();
3369 }
3370
3371 // Always call even when there are not JVMTI environments yet, since environments
3372 // may be attached late and JVMTI must track phases of VM execution
3373 JvmtiExport::enter_start_phase();
3374
3375 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3376 JvmtiExport::post_vm_start();
3377
3378 {
3379 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3380
3381 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3382 create_vm_init_libraries();
3383 }
3384
3385 if (InitializeJavaLangString) {
3386 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3387 } else {
3388 warning("java.lang.String not initialized");
3389 }
3390
3391 if (AggressiveOpts) {
3392 {
3393 // Forcibly initialize java/util/HashMap and mutate the private
3394 // static final "frontCacheEnabled" field before we start creating instances
3395 #ifdef ASSERT
3396 klassOop tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3397 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
3398 #endif
3399 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3400 KlassHandle k = KlassHandle(THREAD, k_o);
3401 guarantee(k.not_null(), "Must find java/util/HashMap");
3402 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3403 ik->initialize(CHECK_0);
3404 fieldDescriptor fd;
3405 // Possible we might not find this field; if so, don't break
3406 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3407 k()->java_mirror()->bool_field_put(fd.offset(), true);
3408 }
3409 }
3410
3411 if (UseStringCache) {
3412 // Forcibly initialize java/lang/StringValue and mutate the private
3413 // static final "stringCacheEnabled" field before we start creating instances
3414 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3415 // Possible that StringValue isn't present: if so, silently don't break
3416 if (k_o != NULL) {
3417 KlassHandle k = KlassHandle(THREAD, k_o);
3418 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3419 ik->initialize(CHECK_0);
3420 fieldDescriptor fd;
3421 // Possible we might not find this field: if so, silently don't break
3422 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3423 k()->java_mirror()->bool_field_put(fd.offset(), true);
3424 }
3425 }
3426 }
3427 }
3428
3429 // Initialize java_lang.System (needed before creating the thread)
3430 if (InitializeJavaLangSystem) {
3431 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3432 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3433 Handle thread_group = create_initial_thread_group(CHECK_0);
3434 Universe::set_main_thread_group(thread_group());
3435 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3436 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3437 main_thread->set_threadObj(thread_object);
3438 // Set thread status to running since main thread has
3439 // been started and running.
3440 java_lang_Thread::set_thread_status(thread_object,
3441 java_lang_Thread::RUNNABLE);
3442
3443 // The VM preresolve methods to these classes. Make sure that get initialized
3444 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3445 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3446 // The VM creates & returns objects of this class. Make sure it's initialized.
3447 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3448 call_initializeSystemClass(CHECK_0);
3449
3450 // get the Java runtime name after java.lang.System is initialized
3451 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3452 } else {
3453 warning("java.lang.System not initialized");
3454 }
3455
3456 // an instance of OutOfMemory exception has been allocated earlier
3457 if (InitializeJavaLangExceptionsErrors) {
3458 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3459 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3460 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3461 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3462 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3463 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3464 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3465 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3466 } else {
3467 warning("java.lang.OutOfMemoryError has not been initialized");
3468 warning("java.lang.NullPointerException has not been initialized");
3469 warning("java.lang.ClassCastException has not been initialized");
3470 warning("java.lang.ArrayStoreException has not been initialized");
3471 warning("java.lang.ArithmeticException has not been initialized");
3472 warning("java.lang.StackOverflowError has not been initialized");
3473 warning("java.lang.IllegalArgumentException has not been initialized");
3474 }
3475 }
3476
3477 // See : bugid 4211085.
3478 // Background : the static initializer of java.lang.Compiler tries to read
3479 // property"java.compiler" and read & write property "java.vm.info".
3480 // When a security manager is installed through the command line
3481 // option "-Djava.security.manager", the above properties are not
3482 // readable and the static initializer for java.lang.Compiler fails
3483 // resulting in a NoClassDefFoundError. This can happen in any
3484 // user code which calls methods in java.lang.Compiler.
3485 // Hack : the hack is to pre-load and initialize this class, so that only
3486 // system domains are on the stack when the properties are read.
3487 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3488 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3489 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3490 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3491 // Once that is done, we should remove this hack.
3492 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3493
3494 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3495 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3496 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3497 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3498 // This should also be taken out as soon as 4211383 gets fixed.
3499 reset_vm_info_property(CHECK_0);
3500
3501 quicken_jni_functions();
3502
3503 // Must be run after init_ft which initializes ft_enabled
3504 if (TRACE_INITIALIZE() != JNI_OK) {
3505 vm_exit_during_initialization("Failed to initialize tracing backend");
3506 }
3507
3508 // Set flag that basic initialization has completed. Used by exceptions and various
3509 // debug stuff, that does not work until all basic classes have been initialized.
3510 set_init_completed();
3511
3512 #ifndef USDT2
3513 HS_DTRACE_PROBE(hotspot, vm__init__end);
3514 #else /* USDT2 */
3515 HOTSPOT_VM_INIT_END();
3516 #endif /* USDT2 */
3517
3518 // record VM initialization completion time
3519 Management::record_vm_init_completed();
3520
3521 // Compute system loader. Note that this has to occur after set_init_completed, since
3522 // valid exceptions may be thrown in the process.
3523 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3524 // set_init_completed has just been called, causing exceptions not to be shortcut
3525 // anymore. We call vm_exit_during_initialization directly instead.
3526 SystemDictionary::compute_java_system_loader(THREAD);
3527 if (HAS_PENDING_EXCEPTION) {
3528 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3529 }
3530
3531 #ifndef SERIALGC
3532 // Support for ConcurrentMarkSweep. This should be cleaned up
3533 // and better encapsulated. The ugly nested if test would go away
3534 // once things are properly refactored. XXX YSR
3535 if (UseConcMarkSweepGC || UseG1GC) {
3536 if (UseConcMarkSweepGC) {
3537 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3538 } else {
3539 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3540 }
3541 if (HAS_PENDING_EXCEPTION) {
3542 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3543 }
3544 }
3545 #endif // SERIALGC
3546
3547 // Always call even when there are not JVMTI environments yet, since environments
3548 // may be attached late and JVMTI must track phases of VM execution
3549 JvmtiExport::enter_live_phase();
3550
3551 // Signal Dispatcher needs to be started before VMInit event is posted
3552 os::signal_init();
3553
3554 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3555 if (!DisableAttachMechanism) {
3556 if (StartAttachListener || AttachListener::init_at_startup()) {
3557 AttachListener::init();
3558 }
3559 }
3560
3561 // Launch -Xrun agents
3562 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3563 // back-end can launch with -Xdebug -Xrunjdwp.
3564 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3565 create_vm_init_libraries();
3566 }
3567
3568 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3569 JvmtiExport::post_vm_initialized();
3570
3571 if (TRACE_START() != JNI_OK) {
3572 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3573 }
3574
3575 if (CleanChunkPoolAsync) {
3576 Chunk::start_chunk_pool_cleaner_task();
3577 }
3578
3579 // initialize compiler(s)
3580 CompileBroker::compilation_init();
3581
3582 Management::initialize(THREAD);
3583 if (HAS_PENDING_EXCEPTION) {
3584 // management agent fails to start possibly due to
3585 // configuration problem and is responsible for printing
3586 // stack trace if appropriate. Simply exit VM.
3587 vm_exit(1);
3588 }
3589
3590 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3591 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3592 if (MemProfiling) MemProfiler::engage();
3593 StatSampler::engage();
3594 if (CheckJNICalls) JniPeriodicChecker::engage();
3595
3596 BiasedLocking::init();
3597
3598 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3599 call_postVMInitHook(THREAD);
3600 // The Java side of PostVMInitHook.run must deal with all
3601 // exceptions and provide means of diagnosis.
3602 if (HAS_PENDING_EXCEPTION) {
3603 CLEAR_PENDING_EXCEPTION;
3604 }
3605 }
3606
3607 {
3608 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3609 // Make sure the watcher thread can be started by WatcherThread::start()
3610 // or by dynamic enrollment.
3611 WatcherThread::make_startable();
3612 // Start up the WatcherThread if there are any periodic tasks
3613 // NOTE: All PeriodicTasks should be registered by now. If they
3614 // aren't, late joiners might appear to start slowly (we might
3615 // take a while to process their first tick).
3616 if (PeriodicTask::num_tasks() > 0) {
3617 WatcherThread::start();
3618 }
3619 }
3620
3621 // Give os specific code one last chance to start
3622 os::init_3();
3623
3624 create_vm_timer.end();
3625 return JNI_OK;
3626 }
3627
3628 // type for the Agent_OnLoad and JVM_OnLoad entry points
3629 extern "C" {
3630 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3631 }
3632 // Find a command line agent library and return its entry point for
3633 // -agentlib: -agentpath: -Xrun
3634 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3635 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3636 OnLoadEntry_t on_load_entry = NULL;
3637 void *library = agent->os_lib(); // check if we have looked it up before
3638
3639 if (library == NULL) {
3640 char buffer[JVM_MAXPATHLEN];
3641 char ebuf[1024];
3642 const char *name = agent->name();
3643 const char *msg = "Could not find agent library ";
3644
3645 if (agent->is_absolute_path()) {
3646 library = os::dll_load(name, ebuf, sizeof ebuf);
3647 if (library == NULL) {
3648 const char *sub_msg = " in absolute path, with error: ";
3649 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3650 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3651 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3652 // If we can't find the agent, exit.
3653 vm_exit_during_initialization(buf, NULL);
3654 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3655 }
3656 } else {
3657 // Try to load the agent from the standard dll directory
3658 os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
3659 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3660 #ifdef KERNEL
3661 // Download instrument dll
3662 if (library == NULL && strcmp(name, "instrument") == 0) {
3663 char *props = Arguments::get_kernel_properties();
3664 char *home = Arguments::get_java_home();
3665 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false"
3666 " sun.jkernel.DownloadManager -download client_jvm";
3667 size_t length = strlen(props) + strlen(home) + strlen(fmt) + 1;
3668 char *cmd = NEW_C_HEAP_ARRAY(char, length, mtThread);
3669 jio_snprintf(cmd, length, fmt, home, props);
3670 int status = os::fork_and_exec(cmd);
3671 FreeHeap(props);
3672 if (status == -1) {
3673 warning(cmd);
3674 vm_exit_during_initialization("fork_and_exec failed: %s",
3675 strerror(errno));
3676 }
3677 FREE_C_HEAP_ARRAY(char, cmd, mtThread);
3678 // when this comes back the instrument.dll should be where it belongs.
3679 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3680 }
3681 #endif // KERNEL
3682 if (library == NULL) { // Try the local directory
3683 char ns[1] = {0};
3684 os::dll_build_name(buffer, sizeof(buffer), ns, name);
3685 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3686 if (library == NULL) {
3687 const char *sub_msg = " on the library path, with error: ";
3688 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3689 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3690 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3691 // If we can't find the agent, exit.
3692 vm_exit_during_initialization(buf, NULL);
3693 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3694 }
3695 }
3696 }
3697 agent->set_os_lib(library);
3698 }
3699
3700 // Find the OnLoad function.
3701 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3702 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index]));
3703 if (on_load_entry != NULL) break;
3704 }
3705 return on_load_entry;
3706 }
3707
3708 // Find the JVM_OnLoad entry point
3709 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3710 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3711 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3712 }
3713
3714 // Find the Agent_OnLoad entry point
3715 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3716 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3717 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3718 }
3719
3720 // For backwards compatibility with -Xrun
3721 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3722 // treated like -agentpath:
3723 // Must be called before agent libraries are created
3724 void Threads::convert_vm_init_libraries_to_agents() {
3725 AgentLibrary* agent;
3726 AgentLibrary* next;
3727
3728 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3729 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3730 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3731
3732 // If there is an JVM_OnLoad function it will get called later,
3733 // otherwise see if there is an Agent_OnLoad
3734 if (on_load_entry == NULL) {
3735 on_load_entry = lookup_agent_on_load(agent);
3736 if (on_load_entry != NULL) {
3737 // switch it to the agent list -- so that Agent_OnLoad will be called,
3738 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3739 Arguments::convert_library_to_agent(agent);
3740 } else {
3741 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3742 }
3743 }
3744 }
3745 }
3746
3747 // Create agents for -agentlib: -agentpath: and converted -Xrun
3748 // Invokes Agent_OnLoad
3749 // Called very early -- before JavaThreads exist
3750 void Threads::create_vm_init_agents() {
3751 extern struct JavaVM_ main_vm;
3752 AgentLibrary* agent;
3753
3754 JvmtiExport::enter_onload_phase();
3755 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3756 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3757
3758 if (on_load_entry != NULL) {
3759 // Invoke the Agent_OnLoad function
3760 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3761 if (err != JNI_OK) {
3762 vm_exit_during_initialization("agent library failed to init", agent->name());
3763 }
3764 } else {
3765 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3766 }
3767 }
3768 JvmtiExport::enter_primordial_phase();
3769 }
3770
3771 extern "C" {
3772 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3773 }
3774
3775 void Threads::shutdown_vm_agents() {
3776 // Send any Agent_OnUnload notifications
3777 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3778 extern struct JavaVM_ main_vm;
3779 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3780
3781 // Find the Agent_OnUnload function.
3782 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3783 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3784 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3785
3786 // Invoke the Agent_OnUnload function
3787 if (unload_entry != NULL) {
3788 JavaThread* thread = JavaThread::current();
3789 ThreadToNativeFromVM ttn(thread);
3790 HandleMark hm(thread);
3791 (*unload_entry)(&main_vm);
3792 break;
3793 }
3794 }
3795 }
3796 }
3797
3798 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3799 // Invokes JVM_OnLoad
3800 void Threads::create_vm_init_libraries() {
3801 extern struct JavaVM_ main_vm;
3802 AgentLibrary* agent;
3803
3804 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3805 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3806
3807 if (on_load_entry != NULL) {
3808 // Invoke the JVM_OnLoad function
3809 JavaThread* thread = JavaThread::current();
3810 ThreadToNativeFromVM ttn(thread);
3811 HandleMark hm(thread);
3812 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3813 if (err != JNI_OK) {
3814 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3815 }
3816 } else {
3817 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3818 }
3819 }
3820 }
3821
3822 // Last thread running calls java.lang.Shutdown.shutdown()
3823 void JavaThread::invoke_shutdown_hooks() {
3824 HandleMark hm(this);
3825
3826 // We could get here with a pending exception, if so clear it now.
3827 if (this->has_pending_exception()) {
3828 this->clear_pending_exception();
3829 }
3830
3831 EXCEPTION_MARK;
3832 klassOop k =
3833 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3834 THREAD);
3835 if (k != NULL) {
3836 // SystemDictionary::resolve_or_null will return null if there was
3837 // an exception. If we cannot load the Shutdown class, just don't
3838 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3839 // and finalizers (if runFinalizersOnExit is set) won't be run.
3840 // Note that if a shutdown hook was registered or runFinalizersOnExit
3841 // was called, the Shutdown class would have already been loaded
3842 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3843 instanceKlassHandle shutdown_klass (THREAD, k);
3844 JavaValue result(T_VOID);
3845 JavaCalls::call_static(&result,
3846 shutdown_klass,
3847 vmSymbols::shutdown_method_name(),
3848 vmSymbols::void_method_signature(),
3849 THREAD);
3850 }
3851 CLEAR_PENDING_EXCEPTION;
3852 }
3853
3854 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3855 // the program falls off the end of main(). Another VM exit path is through
3856 // vm_exit() when the program calls System.exit() to return a value or when
3857 // there is a serious error in VM. The two shutdown paths are not exactly
3858 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3859 // and VM_Exit op at VM level.
3860 //
3861 // Shutdown sequence:
3862 // + Shutdown native memory tracking if it is on
3863 // + Wait until we are the last non-daemon thread to execute
3864 // <-- every thing is still working at this moment -->
3865 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3866 // shutdown hooks, run finalizers if finalization-on-exit
3867 // + Call before_exit(), prepare for VM exit
3868 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3869 // currently the only user of this mechanism is File.deleteOnExit())
3870 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3871 // post thread end and vm death events to JVMTI,
3872 // stop signal thread
3873 // + Call JavaThread::exit(), it will:
3874 // > release JNI handle blocks, remove stack guard pages
3875 // > remove this thread from Threads list
3876 // <-- no more Java code from this thread after this point -->
3877 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3878 // the compiler threads at safepoint
3879 // <-- do not use anything that could get blocked by Safepoint -->
3880 // + Disable tracing at JNI/JVM barriers
3881 // + Set _vm_exited flag for threads that are still running native code
3882 // + Delete this thread
3883 // + Call exit_globals()
3884 // > deletes tty
3885 // > deletes PerfMemory resources
3886 // + Return to caller
3887
3888 bool Threads::destroy_vm() {
3889 JavaThread* thread = JavaThread::current();
3890
3891 // Wait until we are the last non-daemon thread to execute
3892 { MutexLocker nu(Threads_lock);
3893 while (Threads::number_of_non_daemon_threads() > 1 )
3894 // This wait should make safepoint checks, wait without a timeout,
3895 // and wait as a suspend-equivalent condition.
3896 //
3897 // Note: If the FlatProfiler is running and this thread is waiting
3898 // for another non-daemon thread to finish, then the FlatProfiler
3899 // is waiting for the external suspend request on this thread to
3900 // complete. wait_for_ext_suspend_completion() will eventually
3901 // timeout, but that takes time. Making this wait a suspend-
3902 // equivalent condition solves that timeout problem.
3903 //
3904 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3905 Mutex::_as_suspend_equivalent_flag);
3906 }
3907
3908 // Shutdown NMT before exit. Otherwise,
3909 // it will run into trouble when system destroys static variables.
3910 MemTracker::shutdown(MemTracker::NMT_normal);
3911
3912 // Hang forever on exit if we are reporting an error.
3913 if (ShowMessageBoxOnError && is_error_reported()) {
3914 os::infinite_sleep();
3915 }
3916 os::wait_for_keypress_at_exit();
3917
3918 if (JDK_Version::is_jdk12x_version()) {
3919 // We are the last thread running, so check if finalizers should be run.
3920 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3921 HandleMark rm(thread);
3922 Universe::run_finalizers_on_exit();
3923 } else {
3924 // run Java level shutdown hooks
3925 thread->invoke_shutdown_hooks();
3926 }
3927
3928 before_exit(thread);
3929
3930 thread->exit(true);
3931
3932 // Stop VM thread.
3933 {
3934 // 4945125 The vm thread comes to a safepoint during exit.
3935 // GC vm_operations can get caught at the safepoint, and the
3936 // heap is unparseable if they are caught. Grab the Heap_lock
3937 // to prevent this. The GC vm_operations will not be able to
3938 // queue until after the vm thread is dead.
3939 // After this point, we'll never emerge out of the safepoint before
3940 // the VM exits, so concurrent GC threads do not need to be explicitly
3941 // stopped; they remain inactive until the process exits.
3942 // Note: some concurrent G1 threads may be running during a safepoint,
3943 // but these will not be accessing the heap, just some G1-specific side
3944 // data structures that are not accessed by any other threads but them
3945 // after this point in a terminal safepoint.
3946
3947 MutexLocker ml(Heap_lock);
3948
3949 VMThread::wait_for_vm_thread_exit();
3950 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3951 VMThread::destroy();
3952 }
3953
3954 // clean up ideal graph printers
3955 #if defined(COMPILER2) && !defined(PRODUCT)
3956 IdealGraphPrinter::clean_up();
3957 #endif
3958
3959 // Now, all Java threads are gone except daemon threads. Daemon threads
3960 // running Java code or in VM are stopped by the Safepoint. However,
3961 // daemon threads executing native code are still running. But they
3962 // will be stopped at native=>Java/VM barriers. Note that we can't
3963 // simply kill or suspend them, as it is inherently deadlock-prone.
3964
3965 #ifndef PRODUCT
3966 // disable function tracing at JNI/JVM barriers
3967 TraceJNICalls = false;
3968 TraceJVMCalls = false;
3969 TraceRuntimeCalls = false;
3970 #endif
3971
3972 VM_Exit::set_vm_exited();
3973
3974 notify_vm_shutdown();
3975
3976 delete thread;
3977
3978 // exit_globals() will delete tty
3979 exit_globals();
3980
3981 return true;
3982 }
3983
3984
3985 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3986 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3987 return is_supported_jni_version(version);
3988 }
3989
3990
3991 jboolean Threads::is_supported_jni_version(jint version) {
3992 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3993 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3994 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3995 return JNI_FALSE;
3996 }
3997
3998
3999 void Threads::add(JavaThread* p, bool force_daemon) {
4000 // The threads lock must be owned at this point
4001 assert_locked_or_safepoint(Threads_lock);
4002
4003 // See the comment for this method in thread.hpp for its purpose and
4004 // why it is called here.
4005 p->initialize_queues();
4006 p->set_next(_thread_list);
4007 _thread_list = p;
4008 _number_of_threads++;
4009 oop threadObj = p->threadObj();
4010 bool daemon = true;
4011 // Bootstrapping problem: threadObj can be null for initial
4012 // JavaThread (or for threads attached via JNI)
4013 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4014 _number_of_non_daemon_threads++;
4015 daemon = false;
4016 }
4017
4018 p->set_safepoint_visible(true);
4019
4020 ThreadService::add_thread(p, daemon);
4021
4022 // Possible GC point.
4023 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4024 }
4025
4026 void Threads::remove(JavaThread* p) {
4027 // Extra scope needed for Thread_lock, so we can check
4028 // that we do not remove thread without safepoint code notice
4029 { MutexLocker ml(Threads_lock);
4030
4031 assert(includes(p), "p must be present");
4032
4033 JavaThread* current = _thread_list;
4034 JavaThread* prev = NULL;
4035
4036 while (current != p) {
4037 prev = current;
4038 current = current->next();
4039 }
4040
4041 if (prev) {
4042 prev->set_next(current->next());
4043 } else {
4044 _thread_list = p->next();
4045 }
4046 _number_of_threads--;
4047 oop threadObj = p->threadObj();
4048 bool daemon = true;
4049 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4050 _number_of_non_daemon_threads--;
4051 daemon = false;
4052
4053 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4054 // on destroy_vm will wake up.
4055 if (number_of_non_daemon_threads() == 1)
4056 Threads_lock->notify_all();
4057 }
4058 ThreadService::remove_thread(p, daemon);
4059
4060 // Make sure that safepoint code disregard this thread. This is needed since
4061 // the thread might mess around with locks after this point. This can cause it
4062 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4063 // of this thread since it is removed from the queue.
4064 p->set_terminated_value();
4065
4066 // Now, this thread is not visible to safepoint
4067 p->set_safepoint_visible(false);
4068
4069 } // unlock Threads_lock
4070
4071 // Since Events::log uses a lock, we grab it outside the Threads_lock
4072 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4073 }
4074
4075 // Threads_lock must be held when this is called (or must be called during a safepoint)
4076 bool Threads::includes(JavaThread* p) {
4077 assert(Threads_lock->is_locked(), "sanity check");
4078 ALL_JAVA_THREADS(q) {
4079 if (q == p ) {
4080 return true;
4081 }
4082 }
4083 return false;
4084 }
4085
4086 // Operations on the Threads list for GC. These are not explicitly locked,
4087 // but the garbage collector must provide a safe context for them to run.
4088 // In particular, these things should never be called when the Threads_lock
4089 // is held by some other thread. (Note: the Safepoint abstraction also
4090 // uses the Threads_lock to gurantee this property. It also makes sure that
4091 // all threads gets blocked when exiting or starting).
4092
4093 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4094 ALL_JAVA_THREADS(p) {
4095 p->oops_do(f, cf);
4096 }
4097 VMThread::vm_thread()->oops_do(f, cf);
4098 }
4099
4100 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) {
4101 // Introduce a mechanism allowing parallel threads to claim threads as
4102 // root groups. Overhead should be small enough to use all the time,
4103 // even in sequential code.
4104 SharedHeap* sh = SharedHeap::heap();
4105 // Cannot yet substitute active_workers for n_par_threads
4106 // because of G1CollectedHeap::verify() use of
4107 // SharedHeap::process_strong_roots(). n_par_threads == 0 will
4108 // turn off parallelism in process_strong_roots while active_workers
4109 // is being used for parallelism elsewhere.
4110 bool is_par = sh->n_par_threads() > 0;
4111 assert(!is_par ||
4112 (SharedHeap::heap()->n_par_threads() ==
4113 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4114 int cp = SharedHeap::heap()->strong_roots_parity();
4115 ALL_JAVA_THREADS(p) {
4116 if (p->claim_oops_do(is_par, cp)) {
4117 p->oops_do(f, cf);
4118 }
4119 }
4120 VMThread* vmt = VMThread::vm_thread();
4121 if (vmt->claim_oops_do(is_par, cp)) {
4122 vmt->oops_do(f, cf);
4123 }
4124 }
4125
4126 #ifndef SERIALGC
4127 // Used by ParallelScavenge
4128 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4129 ALL_JAVA_THREADS(p) {
4130 q->enqueue(new ThreadRootsTask(p));
4131 }
4132 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4133 }
4134
4135 // Used by Parallel Old
4136 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4137 ALL_JAVA_THREADS(p) {
4138 q->enqueue(new ThreadRootsMarkingTask(p));
4139 }
4140 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4141 }
4142 #endif // SERIALGC
4143
4144 void Threads::nmethods_do(CodeBlobClosure* cf) {
4145 ALL_JAVA_THREADS(p) {
4146 p->nmethods_do(cf);
4147 }
4148 VMThread::vm_thread()->nmethods_do(cf);
4149 }
4150
4151 void Threads::gc_epilogue() {
4152 ALL_JAVA_THREADS(p) {
4153 p->gc_epilogue();
4154 }
4155 }
4156
4157 void Threads::gc_prologue() {
4158 ALL_JAVA_THREADS(p) {
4159 p->gc_prologue();
4160 }
4161 }
4162
4163 void Threads::deoptimized_wrt_marked_nmethods() {
4164 ALL_JAVA_THREADS(p) {
4165 p->deoptimized_wrt_marked_nmethods();
4166 }
4167 }
4168
4169
4170 // Get count Java threads that are waiting to enter the specified monitor.
4171 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4172 address monitor, bool doLock) {
4173 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4174 "must grab Threads_lock or be at safepoint");
4175 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4176
4177 int i = 0;
4178 {
4179 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4180 ALL_JAVA_THREADS(p) {
4181 if (p->is_Compiler_thread()) continue;
4182
4183 address pending = (address)p->current_pending_monitor();
4184 if (pending == monitor) { // found a match
4185 if (i < count) result->append(p); // save the first count matches
4186 i++;
4187 }
4188 }
4189 }
4190 return result;
4191 }
4192
4193
4194 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4195 assert(doLock ||
4196 Threads_lock->owned_by_self() ||
4197 SafepointSynchronize::is_at_safepoint(),
4198 "must grab Threads_lock or be at safepoint");
4199
4200 // NULL owner means not locked so we can skip the search
4201 if (owner == NULL) return NULL;
4202
4203 {
4204 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4205 ALL_JAVA_THREADS(p) {
4206 // first, see if owner is the address of a Java thread
4207 if (owner == (address)p) return p;
4208 }
4209 }
4210 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
4211 if (UseHeavyMonitors) return NULL;
4212
4213 //
4214 // If we didn't find a matching Java thread and we didn't force use of
4215 // heavyweight monitors, then the owner is the stack address of the
4216 // Lock Word in the owning Java thread's stack.
4217 //
4218 JavaThread* the_owner = NULL;
4219 {
4220 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4221 ALL_JAVA_THREADS(q) {
4222 if (q->is_lock_owned(owner)) {
4223 the_owner = q;
4224 break;
4225 }
4226 }
4227 }
4228 assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
4229 return the_owner;
4230 }
4231
4232 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4233 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4234 char buf[32];
4235 st->print_cr(os::local_time_string(buf, sizeof(buf)));
4236
4237 st->print_cr("Full thread dump %s (%s %s):",
4238 Abstract_VM_Version::vm_name(),
4239 Abstract_VM_Version::vm_release(),
4240 Abstract_VM_Version::vm_info_string()
4241 );
4242 st->cr();
4243
4244 #ifndef SERIALGC
4245 // Dump concurrent locks
4246 ConcurrentLocksDump concurrent_locks;
4247 if (print_concurrent_locks) {
4248 concurrent_locks.dump_at_safepoint();
4249 }
4250 #endif // SERIALGC
4251
4252 ALL_JAVA_THREADS(p) {
4253 ResourceMark rm;
4254 p->print_on(st);
4255 if (print_stacks) {
4256 if (internal_format) {
4257 p->trace_stack();
4258 } else {
4259 p->print_stack_on(st);
4260 }
4261 }
4262 st->cr();
4263 #ifndef SERIALGC
4264 if (print_concurrent_locks) {
4265 concurrent_locks.print_locks_on(p, st);
4266 }
4267 #endif // SERIALGC
4268 }
4269
4270 VMThread::vm_thread()->print_on(st);
4271 st->cr();
4272 Universe::heap()->print_gc_threads_on(st);
4273 WatcherThread* wt = WatcherThread::watcher_thread();
4274 if (wt != NULL) wt->print_on(st);
4275 st->cr();
4276 CompileBroker::print_compiler_threads_on(st);
4277 st->flush();
4278 }
4279
4280 // Threads::print_on_error() is called by fatal error handler. It's possible
4281 // that VM is not at safepoint and/or current thread is inside signal handler.
4282 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4283 // memory (even in resource area), it might deadlock the error handler.
4284 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4285 bool found_current = false;
4286 st->print_cr("Java Threads: ( => current thread )");
4287 ALL_JAVA_THREADS(thread) {
4288 bool is_current = (current == thread);
4289 found_current = found_current || is_current;
4290
4291 st->print("%s", is_current ? "=>" : " ");
4292
4293 st->print(PTR_FORMAT, thread);
4294 st->print(" ");
4295 thread->print_on_error(st, buf, buflen);
4296 st->cr();
4297 }
4298 st->cr();
4299
4300 st->print_cr("Other Threads:");
4301 if (VMThread::vm_thread()) {
4302 bool is_current = (current == VMThread::vm_thread());
4303 found_current = found_current || is_current;
4304 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4305
4306 st->print(PTR_FORMAT, VMThread::vm_thread());
4307 st->print(" ");
4308 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4309 st->cr();
4310 }
4311 WatcherThread* wt = WatcherThread::watcher_thread();
4312 if (wt != NULL) {
4313 bool is_current = (current == wt);
4314 found_current = found_current || is_current;
4315 st->print("%s", is_current ? "=>" : " ");
4316
4317 st->print(PTR_FORMAT, wt);
4318 st->print(" ");
4319 wt->print_on_error(st, buf, buflen);
4320 st->cr();
4321 }
4322 if (!found_current) {
4323 st->cr();
4324 st->print("=>" PTR_FORMAT " (exited) ", current);
4325 current->print_on_error(st, buf, buflen);
4326 st->cr();
4327 }
4328 }
4329
4330 // Internal SpinLock and Mutex
4331 // Based on ParkEvent
4332
4333 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4334 //
4335 // We employ SpinLocks _only for low-contention, fixed-length
4336 // short-duration critical sections where we're concerned
4337 // about native mutex_t or HotSpot Mutex:: latency.
4338 // The mux construct provides a spin-then-block mutual exclusion
4339 // mechanism.
4340 //
4341 // Testing has shown that contention on the ListLock guarding gFreeList
4342 // is common. If we implement ListLock as a simple SpinLock it's common
4343 // for the JVM to devolve to yielding with little progress. This is true
4344 // despite the fact that the critical sections protected by ListLock are
4345 // extremely short.
4346 //
4347 // TODO-FIXME: ListLock should be of type SpinLock.
4348 // We should make this a 1st-class type, integrated into the lock
4349 // hierarchy as leaf-locks. Critically, the SpinLock structure
4350 // should have sufficient padding to avoid false-sharing and excessive
4351 // cache-coherency traffic.
4352
4353
4354 typedef volatile int SpinLockT ;
4355
4356 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4357 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4358 return ; // normal fast-path return
4359 }
4360
4361 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4362 TEVENT (SpinAcquire - ctx) ;
4363 int ctr = 0 ;
4364 int Yields = 0 ;
4365 for (;;) {
4366 while (*adr != 0) {
4367 ++ctr ;
4368 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4369 if (Yields > 5) {
4370 // Consider using a simple NakedSleep() instead.
4371 // Then SpinAcquire could be called by non-JVM threads
4372 Thread::current()->_ParkEvent->park(1) ;
4373 } else {
4374 os::NakedYield() ;
4375 ++Yields ;
4376 }
4377 } else {
4378 SpinPause() ;
4379 }
4380 }
4381 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4382 }
4383 }
4384
4385 void Thread::SpinRelease (volatile int * adr) {
4386 assert (*adr != 0, "invariant") ;
4387 OrderAccess::fence() ; // guarantee at least release consistency.
4388 // Roach-motel semantics.
4389 // It's safe if subsequent LDs and STs float "up" into the critical section,
4390 // but prior LDs and STs within the critical section can't be allowed
4391 // to reorder or float past the ST that releases the lock.
4392 *adr = 0 ;
4393 }
4394
4395 // muxAcquire and muxRelease:
4396 //
4397 // * muxAcquire and muxRelease support a single-word lock-word construct.
4398 // The LSB of the word is set IFF the lock is held.
4399 // The remainder of the word points to the head of a singly-linked list
4400 // of threads blocked on the lock.
4401 //
4402 // * The current implementation of muxAcquire-muxRelease uses its own
4403 // dedicated Thread._MuxEvent instance. If we're interested in
4404 // minimizing the peak number of extant ParkEvent instances then
4405 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4406 // as certain invariants were satisfied. Specifically, care would need
4407 // to be taken with regards to consuming unpark() "permits".
4408 // A safe rule of thumb is that a thread would never call muxAcquire()
4409 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4410 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4411 // consume an unpark() permit intended for monitorenter, for instance.
4412 // One way around this would be to widen the restricted-range semaphore
4413 // implemented in park(). Another alternative would be to provide
4414 // multiple instances of the PlatformEvent() for each thread. One
4415 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4416 //
4417 // * Usage:
4418 // -- Only as leaf locks
4419 // -- for short-term locking only as muxAcquire does not perform
4420 // thread state transitions.
4421 //
4422 // Alternatives:
4423 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4424 // but with parking or spin-then-park instead of pure spinning.
4425 // * Use Taura-Oyama-Yonenzawa locks.
4426 // * It's possible to construct a 1-0 lock if we encode the lockword as
4427 // (List,LockByte). Acquire will CAS the full lockword while Release
4428 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4429 // acquiring threads use timers (ParkTimed) to detect and recover from
4430 // the stranding window. Thread/Node structures must be aligned on 256-byte
4431 // boundaries by using placement-new.
4432 // * Augment MCS with advisory back-link fields maintained with CAS().
4433 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4434 // The validity of the backlinks must be ratified before we trust the value.
4435 // If the backlinks are invalid the exiting thread must back-track through the
4436 // the forward links, which are always trustworthy.
4437 // * Add a successor indication. The LockWord is currently encoded as
4438 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4439 // to provide the usual futile-wakeup optimization.
4440 // See RTStt for details.
4441 // * Consider schedctl.sc_nopreempt to cover the critical section.
4442 //
4443
4444
4445 typedef volatile intptr_t MutexT ; // Mux Lock-word
4446 enum MuxBits { LOCKBIT = 1 } ;
4447
4448 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4449 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4450 if (w == 0) return ;
4451 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4452 return ;
4453 }
4454
4455 TEVENT (muxAcquire - Contention) ;
4456 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4457 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4458 for (;;) {
4459 int its = (os::is_MP() ? 100 : 0) + 1 ;
4460
4461 // Optional spin phase: spin-then-park strategy
4462 while (--its >= 0) {
4463 w = *Lock ;
4464 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4465 return ;
4466 }
4467 }
4468
4469 Self->reset() ;
4470 Self->OnList = intptr_t(Lock) ;
4471 // The following fence() isn't _strictly necessary as the subsequent
4472 // CAS() both serializes execution and ratifies the fetched *Lock value.
4473 OrderAccess::fence();
4474 for (;;) {
4475 w = *Lock ;
4476 if ((w & LOCKBIT) == 0) {
4477 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4478 Self->OnList = 0 ; // hygiene - allows stronger asserts
4479 return ;
4480 }
4481 continue ; // Interference -- *Lock changed -- Just retry
4482 }
4483 assert (w & LOCKBIT, "invariant") ;
4484 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4485 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4486 }
4487
4488 while (Self->OnList != 0) {
4489 Self->park() ;
4490 }
4491 }
4492 }
4493
4494 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4495 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4496 if (w == 0) return ;
4497 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4498 return ;
4499 }
4500
4501 TEVENT (muxAcquire - Contention) ;
4502 ParkEvent * ReleaseAfter = NULL ;
4503 if (ev == NULL) {
4504 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4505 }
4506 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4507 for (;;) {
4508 guarantee (ev->OnList == 0, "invariant") ;
4509 int its = (os::is_MP() ? 100 : 0) + 1 ;
4510
4511 // Optional spin phase: spin-then-park strategy
4512 while (--its >= 0) {
4513 w = *Lock ;
4514 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4515 if (ReleaseAfter != NULL) {
4516 ParkEvent::Release (ReleaseAfter) ;
4517 }
4518 return ;
4519 }
4520 }
4521
4522 ev->reset() ;
4523 ev->OnList = intptr_t(Lock) ;
4524 // The following fence() isn't _strictly necessary as the subsequent
4525 // CAS() both serializes execution and ratifies the fetched *Lock value.
4526 OrderAccess::fence();
4527 for (;;) {
4528 w = *Lock ;
4529 if ((w & LOCKBIT) == 0) {
4530 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4531 ev->OnList = 0 ;
4532 // We call ::Release while holding the outer lock, thus
4533 // artificially lengthening the critical section.
4534 // Consider deferring the ::Release() until the subsequent unlock(),
4535 // after we've dropped the outer lock.
4536 if (ReleaseAfter != NULL) {
4537 ParkEvent::Release (ReleaseAfter) ;
4538 }
4539 return ;
4540 }
4541 continue ; // Interference -- *Lock changed -- Just retry
4542 }
4543 assert (w & LOCKBIT, "invariant") ;
4544 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4545 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4546 }
4547
4548 while (ev->OnList != 0) {
4549 ev->park() ;
4550 }
4551 }
4552 }
4553
4554 // Release() must extract a successor from the list and then wake that thread.
4555 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4556 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4557 // Release() would :
4558 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4559 // (B) Extract a successor from the private list "in-hand"
4560 // (C) attempt to CAS() the residual back into *Lock over null.
4561 // If there were any newly arrived threads and the CAS() would fail.
4562 // In that case Release() would detach the RATs, re-merge the list in-hand
4563 // with the RATs and repeat as needed. Alternately, Release() might
4564 // detach and extract a successor, but then pass the residual list to the wakee.
4565 // The wakee would be responsible for reattaching and remerging before it
4566 // competed for the lock.
4567 //
4568 // Both "pop" and DMR are immune from ABA corruption -- there can be
4569 // multiple concurrent pushers, but only one popper or detacher.
4570 // This implementation pops from the head of the list. This is unfair,
4571 // but tends to provide excellent throughput as hot threads remain hot.
4572 // (We wake recently run threads first).
4573
4574 void Thread::muxRelease (volatile intptr_t * Lock) {
4575 for (;;) {
4576 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4577 assert (w & LOCKBIT, "invariant") ;
4578 if (w == LOCKBIT) return ;
4579 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4580 assert (List != NULL, "invariant") ;
4581 assert (List->OnList == intptr_t(Lock), "invariant") ;
4582 ParkEvent * nxt = List->ListNext ;
4583
4584 // The following CAS() releases the lock and pops the head element.
4585 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4586 continue ;
4587 }
4588 List->OnList = 0 ;
4589 OrderAccess::fence() ;
4590 List->unpark () ;
4591 return ;
4592 }
4593 }
4594
4595
4596 void Threads::verify() {
4597 ALL_JAVA_THREADS(p) {
4598 p->verify();
4599 }
4600 VMThread* thread = VMThread::vm_thread();
4601 if (thread != NULL) thread->verify();
4602 }