1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jvmtifiles/jvmtiEnv.hpp"
36 #include "memory/gcLocker.inline.hpp"
37 #include "memory/metaspaceShared.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "memory/universe.inline.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/objArrayOop.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/symbol.hpp"
44 #include "prims/jvm_misc.hpp"
45 #include "prims/jvmtiExport.hpp"
46 #include "prims/jvmtiThreadState.hpp"
47 #include "prims/privilegedStack.hpp"
48 #include "runtime/arguments.hpp"
49 #include "runtime/atomic.inline.hpp"
50 #include "runtime/biasedLocking.hpp"
51 #include "runtime/deoptimization.hpp"
52 #include "runtime/fprofiler.hpp"
53 #include "runtime/frame.inline.hpp"
54 #include "runtime/init.hpp"
55 #include "runtime/interfaceSupport.hpp"
56 #include "runtime/java.hpp"
57 #include "runtime/javaCalls.hpp"
58 #include "runtime/jniPeriodicChecker.hpp"
59 #include "runtime/memprofiler.hpp"
60 #include "runtime/mutexLocker.hpp"
61 #include "runtime/objectMonitor.hpp"
62 #include "runtime/orderAccess.inline.hpp"
63 #include "runtime/osThread.hpp"
64 #include "runtime/safepoint.hpp"
65 #include "runtime/sharedRuntime.hpp"
66 #include "runtime/statSampler.hpp"
67 #include "runtime/stubRoutines.hpp"
68 #include "runtime/task.hpp"
69 #include "runtime/thread.inline.hpp"
70 #include "runtime/threadCritical.hpp"
71 #include "runtime/threadLocalStorage.hpp"
72 #include "runtime/vframe.hpp"
73 #include "runtime/vframeArray.hpp"
74 #include "runtime/vframe_hp.hpp"
75 #include "runtime/vmThread.hpp"
76 #include "runtime/vm_operations.hpp"
77 #include "services/attachListener.hpp"
78 #include "services/management.hpp"
79 #include "services/memTracker.hpp"
80 #include "services/threadService.hpp"
81 #include "trace/tracing.hpp"
82 #include "trace/traceMacros.hpp"
83 #include "utilities/defaultStream.hpp"
84 #include "utilities/dtrace.hpp"
85 #include "utilities/events.hpp"
86 #include "utilities/preserveException.hpp"
87 #include "utilities/macros.hpp"
88 #ifdef TARGET_OS_FAMILY_linux
89 # include "os_linux.inline.hpp"
90 #endif
91 #ifdef TARGET_OS_FAMILY_solaris
92 # include "os_solaris.inline.hpp"
93 #endif
94 #ifdef TARGET_OS_FAMILY_windows
95 # include "os_windows.inline.hpp"
96 #endif
97 #ifdef TARGET_OS_FAMILY_bsd
98 # include "os_bsd.inline.hpp"
99 #endif
100 #if INCLUDE_ALL_GCS
101 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
102 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
103 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
104 #endif // INCLUDE_ALL_GCS
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 #if INCLUDE_RTM_OPT
113 #include "runtime/rtmLocking.hpp"
114 #endif
115
116 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
117
118 #ifdef DTRACE_ENABLED
119
120 // Only bother with this argument setup if dtrace is available
121
122 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
123 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
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 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
132 (char *) name, len, \
133 java_lang_Thread::thread_id((javathread)->threadObj()), \
134 (uintptr_t) (javathread)->osthread()->thread_id(), \
135 java_lang_Thread::is_daemon((javathread)->threadObj())); \
136 }
137
138 #else // ndef DTRACE_ENABLED
139
140 #define DTRACE_THREAD_PROBE(probe, javathread)
141
142 #endif // ndef DTRACE_ENABLED
143
144
145 // Class hierarchy
146 // - Thread
147 // - VMThread
148 // - WatcherThread
149 // - ConcurrentMarkSweepThread
150 // - JavaThread
151 // - CompilerThread
152
153 // ======= Thread ========
154 // Support for forcing alignment of thread objects for biased locking
155 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
156 if (UseBiasedLocking) {
157 const int alignment = markOopDesc::biased_lock_alignment;
158 size_t aligned_size = size + (alignment - sizeof(intptr_t));
159 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
160 : AllocateHeap(aligned_size, flags, CURRENT_PC,
161 AllocFailStrategy::RETURN_NULL);
162 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
163 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
164 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
165 "JavaThread alignment code overflowed allocated storage");
166 if (TraceBiasedLocking) {
167 if (aligned_addr != real_malloc_addr)
168 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
169 real_malloc_addr, aligned_addr);
170 }
171 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
172 return aligned_addr;
173 } else {
174 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
175 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
176 }
177 }
178
179 void Thread::operator delete(void* p) {
180 if (UseBiasedLocking) {
181 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
182 FreeHeap(real_malloc_addr, mtThread);
183 } else {
184 FreeHeap(p, mtThread);
185 }
186 }
187
188
189 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
190 // JavaThread
191
192
193 Thread::Thread() {
194 // stack and get_thread
195 set_stack_base(NULL);
196 set_stack_size(0);
197 set_self_raw_id(0);
198 set_lgrp_id(-1);
199
200 // allocated data structures
201 set_osthread(NULL);
202 set_resource_area(new (mtThread)ResourceArea());
203 DEBUG_ONLY(_current_resource_mark = NULL;)
204 set_handle_area(new (mtThread) HandleArea(NULL));
205 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
206 set_active_handles(NULL);
207 set_free_handle_block(NULL);
208 set_last_handle_mark(NULL);
209
210 // This initial value ==> never claimed.
211 _oops_do_parity = 0;
212
213 // the handle mark links itself to last_handle_mark
214 new HandleMark(this);
215
216 // plain initialization
217 debug_only(_owned_locks = NULL;)
218 debug_only(_allow_allocation_count = 0;)
219 NOT_PRODUCT(_allow_safepoint_count = 0;)
220 NOT_PRODUCT(_skip_gcalot = false;)
221 _jvmti_env_iteration_count = 0;
222 set_allocated_bytes(0);
223 _vm_operation_started_count = 0;
224 _vm_operation_completed_count = 0;
225 _current_pending_monitor = NULL;
226 _current_pending_monitor_is_from_java = true;
227 _current_waiting_monitor = NULL;
228 _num_nested_signal = 0;
229 omFreeList = NULL;
230 omFreeCount = 0;
231 omFreeProvision = 32;
232 omInUseList = NULL;
233 omInUseCount = 0;
234
235 #ifdef ASSERT
236 _visited_for_critical_count = false;
237 #endif
238
239 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
240 _suspend_flags = 0;
241
242 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
243 _hashStateX = os::random();
244 _hashStateY = 842502087;
245 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
246 _hashStateW = 273326509;
247
248 _OnTrap = 0;
249 _schedctl = NULL;
250 _Stalled = 0;
251 _TypeTag = 0x2BAD;
252
253 // Many of the following fields are effectively final - immutable
254 // Note that nascent threads can't use the Native Monitor-Mutex
255 // construct until the _MutexEvent is initialized ...
256 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
257 // we might instead use a stack of ParkEvents that we could provision on-demand.
258 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
259 // and ::Release()
260 _ParkEvent = ParkEvent::Allocate(this);
261 _SleepEvent = ParkEvent::Allocate(this);
262 _MutexEvent = ParkEvent::Allocate(this);
263 _MuxEvent = ParkEvent::Allocate(this);
264
265 #ifdef CHECK_UNHANDLED_OOPS
266 if (CheckUnhandledOops) {
267 _unhandled_oops = new UnhandledOops(this);
268 }
269 #endif // CHECK_UNHANDLED_OOPS
270 #ifdef ASSERT
271 if (UseBiasedLocking) {
272 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
273 assert(this == _real_malloc_address ||
274 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
275 "bug in forced alignment of thread objects");
276 }
277 #endif /* ASSERT */
278 }
279
280 void Thread::initialize_thread_local_storage() {
281 // Note: Make sure this method only calls
282 // non-blocking operations. Otherwise, it might not work
283 // with the thread-startup/safepoint interaction.
284
285 // During Java thread startup, safepoint code should allow this
286 // method to complete because it may need to allocate memory to
287 // store information for the new thread.
288
289 // initialize structure dependent on thread local storage
290 ThreadLocalStorage::set_thread(this);
291 }
292
293 void Thread::record_stack_base_and_size() {
294 set_stack_base(os::current_stack_base());
295 set_stack_size(os::current_stack_size());
296 if (is_Java_thread()) {
297 ((JavaThread*) this)->set_stack_overflow_limit();
298 }
299 // CR 7190089: on Solaris, primordial thread's stack is adjusted
300 // in initialize_thread(). Without the adjustment, stack size is
301 // incorrect if stack is set to unlimited (ulimit -s unlimited).
302 // So far, only Solaris has real implementation of initialize_thread().
303 //
304 // set up any platform-specific state.
305 os::initialize_thread(this);
306
307 #if INCLUDE_NMT
308 // record thread's native stack, stack grows downward
309 address stack_low_addr = stack_base() - stack_size();
310 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this,
311 CURRENT_PC);
312 #endif // INCLUDE_NMT
313 }
314
315
316 Thread::~Thread() {
317 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
318 ObjectSynchronizer::omFlush(this);
319
320 EVENT_THREAD_DESTRUCT(this);
321
322 // stack_base can be NULL if the thread is never started or exited before
323 // record_stack_base_and_size called. Although, we would like to ensure
324 // that all started threads do call record_stack_base_and_size(), there is
325 // not proper way to enforce that.
326 #if INCLUDE_NMT
327 if (_stack_base != NULL) {
328 address low_stack_addr = stack_base() - stack_size();
329 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this);
330 #ifdef ASSERT
331 set_stack_base(NULL);
332 #endif
333 }
334 #endif // INCLUDE_NMT
335
336 // deallocate data structures
337 delete resource_area();
338 // since the handle marks are using the handle area, we have to deallocated the root
339 // handle mark before deallocating the thread's handle area,
340 assert(last_handle_mark() != NULL, "check we have an element");
341 delete last_handle_mark();
342 assert(last_handle_mark() == NULL, "check we have reached the end");
343
344 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
345 // We NULL out the fields for good hygiene.
346 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
347 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
348 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
349 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
350
351 delete handle_area();
352 delete metadata_handles();
353
354 // osthread() can be NULL, if creation of thread failed.
355 if (osthread() != NULL) os::free_thread(osthread());
356
357 delete _SR_lock;
358
359 // clear thread local storage if the Thread is deleting itself
360 if (this == Thread::current()) {
361 ThreadLocalStorage::set_thread(NULL);
362 } else {
363 // In the case where we're not the current thread, invalidate all the
364 // caches in case some code tries to get the current thread or the
365 // thread that was destroyed, and gets stale information.
366 ThreadLocalStorage::invalidate_all();
367 }
368 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
369 }
370
371 // NOTE: dummy function for assertion purpose.
372 void Thread::run() {
373 ShouldNotReachHere();
374 }
375
376 #ifdef ASSERT
377 // Private method to check for dangling thread pointer
378 void check_for_dangling_thread_pointer(Thread *thread) {
379 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
380 "possibility of dangling Thread pointer");
381 }
382 #endif
383
384
385 #ifndef PRODUCT
386 // Tracing method for basic thread operations
387 void Thread::trace(const char* msg, const Thread* const thread) {
388 if (!TraceThreadEvents) return;
389 ResourceMark rm;
390 ThreadCritical tc;
391 const char *name = "non-Java thread";
392 int prio = -1;
393 if (thread->is_Java_thread()
394 && !thread->is_Compiler_thread()) {
395 // The Threads_lock must be held to get information about
396 // this thread but may not be in some situations when
397 // tracing thread events.
398 bool release_Threads_lock = false;
399 if (!Threads_lock->owned_by_self()) {
400 Threads_lock->lock();
401 release_Threads_lock = true;
402 }
403 JavaThread* jt = (JavaThread *)thread;
404 name = (char *)jt->get_thread_name();
405 oop thread_oop = jt->threadObj();
406 if (thread_oop != NULL) {
407 prio = java_lang_Thread::priority(thread_oop);
408 }
409 if (release_Threads_lock) {
410 Threads_lock->unlock();
411 }
412 }
413 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
414 }
415 #endif
416
417
418 ThreadPriority Thread::get_priority(const Thread* const thread) {
419 trace("get priority", thread);
420 ThreadPriority priority;
421 // Can return an error!
422 (void)os::get_priority(thread, priority);
423 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
424 return priority;
425 }
426
427 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
428 trace("set priority", thread);
429 debug_only(check_for_dangling_thread_pointer(thread);)
430 // Can return an error!
431 (void)os::set_priority(thread, priority);
432 }
433
434
435 void Thread::start(Thread* thread) {
436 trace("start", thread);
437 // Start is different from resume in that its safety is guaranteed by context or
438 // being called from a Java method synchronized on the Thread object.
439 if (!DisableStartThread) {
440 if (thread->is_Java_thread()) {
441 // Initialize the thread state to RUNNABLE before starting this thread.
442 // Can not set it after the thread started because we do not know the
443 // exact thread state at that time. It could be in MONITOR_WAIT or
444 // in SLEEPING or some other state.
445 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
446 java_lang_Thread::RUNNABLE);
447 }
448 os::start_thread(thread);
449 }
450 }
451
452 // Enqueue a VM_Operation to do the job for us - sometime later
453 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
454 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
455 VMThread::execute(vm_stop);
456 }
457
458
459 //
460 // Check if an external suspend request has completed (or has been
461 // cancelled). Returns true if the thread is externally suspended and
462 // false otherwise.
463 //
464 // The bits parameter returns information about the code path through
465 // the routine. Useful for debugging:
466 //
467 // set in is_ext_suspend_completed():
468 // 0x00000001 - routine was entered
469 // 0x00000010 - routine return false at end
470 // 0x00000100 - thread exited (return false)
471 // 0x00000200 - suspend request cancelled (return false)
472 // 0x00000400 - thread suspended (return true)
473 // 0x00001000 - thread is in a suspend equivalent state (return true)
474 // 0x00002000 - thread is native and walkable (return true)
475 // 0x00004000 - thread is native_trans and walkable (needed retry)
476 //
477 // set in wait_for_ext_suspend_completion():
478 // 0x00010000 - routine was entered
479 // 0x00020000 - suspend request cancelled before loop (return false)
480 // 0x00040000 - thread suspended before loop (return true)
481 // 0x00080000 - suspend request cancelled in loop (return false)
482 // 0x00100000 - thread suspended in loop (return true)
483 // 0x00200000 - suspend not completed during retry loop (return false)
484 //
485
486 // Helper class for tracing suspend wait debug bits.
487 //
488 // 0x00000100 indicates that the target thread exited before it could
489 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
490 // 0x00080000 each indicate a cancelled suspend request so they don't
491 // count as wait failures either.
492 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
493
494 class TraceSuspendDebugBits : public StackObj {
495 private:
496 JavaThread * jt;
497 bool is_wait;
498 bool called_by_wait; // meaningful when !is_wait
499 uint32_t * bits;
500
501 public:
502 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
503 uint32_t *_bits) {
504 jt = _jt;
505 is_wait = _is_wait;
506 called_by_wait = _called_by_wait;
507 bits = _bits;
508 }
509
510 ~TraceSuspendDebugBits() {
511 if (!is_wait) {
512 #if 1
513 // By default, don't trace bits for is_ext_suspend_completed() calls.
514 // That trace is very chatty.
515 return;
516 #else
517 if (!called_by_wait) {
518 // If tracing for is_ext_suspend_completed() is enabled, then only
519 // trace calls to it from wait_for_ext_suspend_completion()
520 return;
521 }
522 #endif
523 }
524
525 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
526 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
527 MutexLocker ml(Threads_lock); // needed for get_thread_name()
528 ResourceMark rm;
529
530 tty->print_cr(
531 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
532 jt->get_thread_name(), *bits);
533
534 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
535 }
536 }
537 }
538 };
539 #undef DEBUG_FALSE_BITS
540
541
542 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
543 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
544
545 bool did_trans_retry = false; // only do thread_in_native_trans retry once
546 bool do_trans_retry; // flag to force the retry
547
548 *bits |= 0x00000001;
549
550 do {
551 do_trans_retry = false;
552
553 if (is_exiting()) {
554 // Thread is in the process of exiting. This is always checked
555 // first to reduce the risk of dereferencing a freed JavaThread.
556 *bits |= 0x00000100;
557 return false;
558 }
559
560 if (!is_external_suspend()) {
561 // Suspend request is cancelled. This is always checked before
562 // is_ext_suspended() to reduce the risk of a rogue resume
563 // confusing the thread that made the suspend request.
564 *bits |= 0x00000200;
565 return false;
566 }
567
568 if (is_ext_suspended()) {
569 // thread is suspended
570 *bits |= 0x00000400;
571 return true;
572 }
573
574 // Now that we no longer do hard suspends of threads running
575 // native code, the target thread can be changing thread state
576 // while we are in this routine:
577 //
578 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
579 //
580 // We save a copy of the thread state as observed at this moment
581 // and make our decision about suspend completeness based on the
582 // copy. This closes the race where the thread state is seen as
583 // _thread_in_native_trans in the if-thread_blocked check, but is
584 // seen as _thread_blocked in if-thread_in_native_trans check.
585 JavaThreadState save_state = thread_state();
586
587 if (save_state == _thread_blocked && is_suspend_equivalent()) {
588 // If the thread's state is _thread_blocked and this blocking
589 // condition is known to be equivalent to a suspend, then we can
590 // consider the thread to be externally suspended. This means that
591 // the code that sets _thread_blocked has been modified to do
592 // self-suspension if the blocking condition releases. We also
593 // used to check for CONDVAR_WAIT here, but that is now covered by
594 // the _thread_blocked with self-suspension check.
595 //
596 // Return true since we wouldn't be here unless there was still an
597 // external suspend request.
598 *bits |= 0x00001000;
599 return true;
600 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
601 // Threads running native code will self-suspend on native==>VM/Java
602 // transitions. If its stack is walkable (should always be the case
603 // unless this function is called before the actual java_suspend()
604 // call), then the wait is done.
605 *bits |= 0x00002000;
606 return true;
607 } else if (!called_by_wait && !did_trans_retry &&
608 save_state == _thread_in_native_trans &&
609 frame_anchor()->walkable()) {
610 // The thread is transitioning from thread_in_native to another
611 // thread state. check_safepoint_and_suspend_for_native_trans()
612 // will force the thread to self-suspend. If it hasn't gotten
613 // there yet we may have caught the thread in-between the native
614 // code check above and the self-suspend. Lucky us. If we were
615 // called by wait_for_ext_suspend_completion(), then it
616 // will be doing the retries so we don't have to.
617 //
618 // Since we use the saved thread state in the if-statement above,
619 // there is a chance that the thread has already transitioned to
620 // _thread_blocked by the time we get here. In that case, we will
621 // make a single unnecessary pass through the logic below. This
622 // doesn't hurt anything since we still do the trans retry.
623
624 *bits |= 0x00004000;
625
626 // Once the thread leaves thread_in_native_trans for another
627 // thread state, we break out of this retry loop. We shouldn't
628 // need this flag to prevent us from getting back here, but
629 // sometimes paranoia is good.
630 did_trans_retry = true;
631
632 // We wait for the thread to transition to a more usable state.
633 for (int i = 1; i <= SuspendRetryCount; i++) {
634 // We used to do an "os::yield_all(i)" call here with the intention
635 // that yielding would increase on each retry. However, the parameter
636 // is ignored on Linux which means the yield didn't scale up. Waiting
637 // on the SR_lock below provides a much more predictable scale up for
638 // the delay. It also provides a simple/direct point to check for any
639 // safepoint requests from the VMThread
640
641 // temporarily drops SR_lock while doing wait with safepoint check
642 // (if we're a JavaThread - the WatcherThread can also call this)
643 // and increase delay with each retry
644 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
645
646 // check the actual thread state instead of what we saved above
647 if (thread_state() != _thread_in_native_trans) {
648 // the thread has transitioned to another thread state so
649 // try all the checks (except this one) one more time.
650 do_trans_retry = true;
651 break;
652 }
653 } // end retry loop
654
655
656 }
657 } while (do_trans_retry);
658
659 *bits |= 0x00000010;
660 return false;
661 }
662
663 //
664 // Wait for an external suspend request to complete (or be cancelled).
665 // Returns true if the thread is externally suspended and false otherwise.
666 //
667 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
668 uint32_t *bits) {
669 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
670 false /* !called_by_wait */, bits);
671
672 // local flag copies to minimize SR_lock hold time
673 bool is_suspended;
674 bool pending;
675 uint32_t reset_bits;
676
677 // set a marker so is_ext_suspend_completed() knows we are the caller
678 *bits |= 0x00010000;
679
680 // We use reset_bits to reinitialize the bits value at the top of
681 // each retry loop. This allows the caller to make use of any
682 // unused bits for their own marking purposes.
683 reset_bits = *bits;
684
685 {
686 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
687 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
688 delay, bits);
689 pending = is_external_suspend();
690 }
691 // must release SR_lock to allow suspension to complete
692
693 if (!pending) {
694 // A cancelled suspend request is the only false return from
695 // is_ext_suspend_completed() that keeps us from entering the
696 // retry loop.
697 *bits |= 0x00020000;
698 return false;
699 }
700
701 if (is_suspended) {
702 *bits |= 0x00040000;
703 return true;
704 }
705
706 for (int i = 1; i <= retries; i++) {
707 *bits = reset_bits; // reinit to only track last retry
708
709 // We used to do an "os::yield_all(i)" call here with the intention
710 // that yielding would increase on each retry. However, the parameter
711 // is ignored on Linux which means the yield didn't scale up. Waiting
712 // on the SR_lock below provides a much more predictable scale up for
713 // the delay. It also provides a simple/direct point to check for any
714 // safepoint requests from the VMThread
715
716 {
717 MutexLocker ml(SR_lock());
718 // wait with safepoint check (if we're a JavaThread - the WatcherThread
719 // can also call this) and increase delay with each retry
720 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
721
722 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
723 delay, bits);
724
725 // It is possible for the external suspend request to be cancelled
726 // (by a resume) before the actual suspend operation is completed.
727 // Refresh our local copy to see if we still need to wait.
728 pending = is_external_suspend();
729 }
730
731 if (!pending) {
732 // A cancelled suspend request is the only false return from
733 // is_ext_suspend_completed() that keeps us from staying in the
734 // retry loop.
735 *bits |= 0x00080000;
736 return false;
737 }
738
739 if (is_suspended) {
740 *bits |= 0x00100000;
741 return true;
742 }
743 } // end retry loop
744
745 // thread did not suspend after all our retries
746 *bits |= 0x00200000;
747 return false;
748 }
749
750 #ifndef PRODUCT
751 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
752
753 // This should not need to be atomic as the only way for simultaneous
754 // updates is via interrupts. Even then this should be rare or non-existent
755 // and we don't care that much anyway.
756
757 int index = _jmp_ring_index;
758 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
759 _jmp_ring[index]._target = (intptr_t) target;
760 _jmp_ring[index]._instruction = (intptr_t) instr;
761 _jmp_ring[index]._file = file;
762 _jmp_ring[index]._line = line;
763 }
764 #endif /* PRODUCT */
765
766 // Called by flat profiler
767 // Callers have already called wait_for_ext_suspend_completion
768 // The assertion for that is currently too complex to put here:
769 bool JavaThread::profile_last_Java_frame(frame* _fr) {
770 bool gotframe = false;
771 // self suspension saves needed state.
772 if (has_last_Java_frame() && _anchor.walkable()) {
773 *_fr = pd_last_frame();
774 gotframe = true;
775 }
776 return gotframe;
777 }
778
779 void Thread::interrupt(Thread* thread) {
780 trace("interrupt", thread);
781 debug_only(check_for_dangling_thread_pointer(thread);)
782 os::interrupt(thread);
783 }
784
785 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
786 trace("is_interrupted", thread);
787 debug_only(check_for_dangling_thread_pointer(thread);)
788 // Note: If clear_interrupted==false, this simply fetches and
789 // returns the value of the field osthread()->interrupted().
790 return os::is_interrupted(thread, clear_interrupted);
791 }
792
793
794 // GC Support
795 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
796 jint thread_parity = _oops_do_parity;
797 if (thread_parity != strong_roots_parity) {
798 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
799 if (res == thread_parity) {
800 return true;
801 } else {
802 guarantee(res == strong_roots_parity, "Or else what?");
803 assert(SharedHeap::heap()->workers()->active_workers() > 0,
804 "Should only fail when parallel.");
805 return false;
806 }
807 }
808 assert(SharedHeap::heap()->workers()->active_workers() > 0,
809 "Should only fail when parallel.");
810 return false;
811 }
812
813 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
814 active_handles()->oops_do(f);
815 // Do oop for ThreadShadow
816 f->do_oop((oop*)&_pending_exception);
817 handle_area()->oops_do(f);
818 }
819
820 void Thread::nmethods_do(CodeBlobClosure* cf) {
821 // no nmethods in a generic thread...
822 }
823
824 void Thread::metadata_do(void f(Metadata*)) {
825 if (metadata_handles() != NULL) {
826 for (int i = 0; i< metadata_handles()->length(); i++) {
827 f(metadata_handles()->at(i));
828 }
829 }
830 }
831
832 void Thread::print_on(outputStream* st) const {
833 // get_priority assumes osthread initialized
834 if (osthread() != NULL) {
835 int os_prio;
836 if (os::get_native_priority(this, &os_prio) == OS_OK) {
837 st->print("os_prio=%d ", os_prio);
838 }
839 st->print("tid=" INTPTR_FORMAT " ", this);
840 osthread()->print_on(st);
841 }
842 debug_only(if (WizardMode) print_owned_locks_on(st);)
843 }
844
845 // Thread::print_on_error() is called by fatal error handler. Don't use
846 // any lock or allocate memory.
847 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
848 if (is_VM_thread()) st->print("VMThread");
849 else if (is_Compiler_thread()) st->print("CompilerThread");
850 else if (is_Java_thread()) st->print("JavaThread");
851 else if (is_GC_task_thread()) st->print("GCTaskThread");
852 else if (is_Watcher_thread()) st->print("WatcherThread");
853 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
854 else st->print("Thread");
855
856 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
857 _stack_base - _stack_size, _stack_base);
858
859 if (osthread()) {
860 st->print(" [id=%d]", osthread()->thread_id());
861 }
862 }
863
864 #ifdef ASSERT
865 void Thread::print_owned_locks_on(outputStream* st) const {
866 Monitor *cur = _owned_locks;
867 if (cur == NULL) {
868 st->print(" (no locks) ");
869 } else {
870 st->print_cr(" Locks owned:");
871 while (cur) {
872 cur->print_on(st);
873 cur = cur->next();
874 }
875 }
876 }
877
878 static int ref_use_count = 0;
879
880 bool Thread::owns_locks_but_compiled_lock() const {
881 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
882 if (cur != Compile_lock) return true;
883 }
884 return false;
885 }
886
887
888 #endif
889
890 #ifndef PRODUCT
891
892 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
893 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
894 // no threads which allow_vm_block's are held
895 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
896 // Check if current thread is allowed to block at a safepoint
897 if (!(_allow_safepoint_count == 0))
898 fatal("Possible safepoint reached by thread that does not allow it");
899 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
900 fatal("LEAF method calling lock?");
901 }
902
903 #ifdef ASSERT
904 if (potential_vm_operation && is_Java_thread()
905 && !Universe::is_bootstrapping()) {
906 // Make sure we do not hold any locks that the VM thread also uses.
907 // This could potentially lead to deadlocks
908 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
909 // Threads_lock is special, since the safepoint synchronization will not start before this is
910 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
911 // since it is used to transfer control between JavaThreads and the VMThread
912 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
913 if ((cur->allow_vm_block() &&
914 cur != Threads_lock &&
915 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
916 cur != VMOperationRequest_lock &&
917 cur != VMOperationQueue_lock) ||
918 cur->rank() == Mutex::special) {
919 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
920 }
921 }
922 }
923
924 if (GCALotAtAllSafepoints) {
925 // We could enter a safepoint here and thus have a gc
926 InterfaceSupport::check_gc_alot();
927 }
928 #endif
929 }
930 #endif
931
932 bool Thread::is_in_stack(address adr) const {
933 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
934 address end = os::current_stack_pointer();
935 // Allow non Java threads to call this without stack_base
936 if (_stack_base == NULL) return true;
937 if (stack_base() >= adr && adr >= end) return true;
938
939 return false;
940 }
941
942
943 bool Thread::is_in_usable_stack(address adr) const {
944 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
945 size_t usable_stack_size = _stack_size - stack_guard_size;
946
947 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
948 }
949
950
951 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
952 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
953 // used for compilation in the future. If that change is made, the need for these methods
954 // should be revisited, and they should be removed if possible.
955
956 bool Thread::is_lock_owned(address adr) const {
957 return on_local_stack(adr);
958 }
959
960 bool Thread::set_as_starting_thread() {
961 // NOTE: this must be called inside the main thread.
962 return os::create_main_thread((JavaThread*)this);
963 }
964
965 static void initialize_class(Symbol* class_name, TRAPS) {
966 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
967 InstanceKlass::cast(klass)->initialize(CHECK);
968 }
969
970
971 // Creates the initial ThreadGroup
972 static Handle create_initial_thread_group(TRAPS) {
973 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
974 instanceKlassHandle klass (THREAD, k);
975
976 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
977 {
978 JavaValue result(T_VOID);
979 JavaCalls::call_special(&result,
980 system_instance,
981 klass,
982 vmSymbols::object_initializer_name(),
983 vmSymbols::void_method_signature(),
984 CHECK_NH);
985 }
986 Universe::set_system_thread_group(system_instance());
987
988 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
989 {
990 JavaValue result(T_VOID);
991 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
992 JavaCalls::call_special(&result,
993 main_instance,
994 klass,
995 vmSymbols::object_initializer_name(),
996 vmSymbols::threadgroup_string_void_signature(),
997 system_instance,
998 string,
999 CHECK_NH);
1000 }
1001 return main_instance;
1002 }
1003
1004 // Creates the initial Thread
1005 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1006 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1007 instanceKlassHandle klass (THREAD, k);
1008 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1009
1010 java_lang_Thread::set_thread(thread_oop(), thread);
1011 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1012 thread->set_threadObj(thread_oop());
1013
1014 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1015
1016 JavaValue result(T_VOID);
1017 JavaCalls::call_special(&result, thread_oop,
1018 klass,
1019 vmSymbols::object_initializer_name(),
1020 vmSymbols::threadgroup_string_void_signature(),
1021 thread_group,
1022 string,
1023 CHECK_NULL);
1024 return thread_oop();
1025 }
1026
1027 static void call_initializeSystemClass(TRAPS) {
1028 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1029 instanceKlassHandle klass (THREAD, k);
1030
1031 JavaValue result(T_VOID);
1032 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1033 vmSymbols::void_method_signature(), CHECK);
1034 }
1035
1036 char java_runtime_name[128] = "";
1037 char java_runtime_version[128] = "";
1038
1039 // extract the JRE name from sun.misc.Version.java_runtime_name
1040 static const char* get_java_runtime_name(TRAPS) {
1041 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1042 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1043 fieldDescriptor fd;
1044 bool found = k != NULL &&
1045 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1046 vmSymbols::string_signature(), &fd);
1047 if (found) {
1048 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1049 if (name_oop == NULL)
1050 return NULL;
1051 const char* name = java_lang_String::as_utf8_string(name_oop,
1052 java_runtime_name,
1053 sizeof(java_runtime_name));
1054 return name;
1055 } else {
1056 return NULL;
1057 }
1058 }
1059
1060 // extract the JRE version from sun.misc.Version.java_runtime_version
1061 static const char* get_java_runtime_version(TRAPS) {
1062 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1063 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1064 fieldDescriptor fd;
1065 bool found = k != NULL &&
1066 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1067 vmSymbols::string_signature(), &fd);
1068 if (found) {
1069 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1070 if (name_oop == NULL)
1071 return NULL;
1072 const char* name = java_lang_String::as_utf8_string(name_oop,
1073 java_runtime_version,
1074 sizeof(java_runtime_version));
1075 return name;
1076 } else {
1077 return NULL;
1078 }
1079 }
1080
1081 // General purpose hook into Java code, run once when the VM is initialized.
1082 // The Java library method itself may be changed independently from the VM.
1083 static void call_postVMInitHook(TRAPS) {
1084 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1085 instanceKlassHandle klass (THREAD, k);
1086 if (klass.not_null()) {
1087 JavaValue result(T_VOID);
1088 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1089 vmSymbols::void_method_signature(),
1090 CHECK);
1091 }
1092 }
1093
1094 static void reset_vm_info_property(TRAPS) {
1095 // the vm info string
1096 ResourceMark rm(THREAD);
1097 const char *vm_info = VM_Version::vm_info_string();
1098
1099 // java.lang.System class
1100 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1101 instanceKlassHandle klass (THREAD, k);
1102
1103 // setProperty arguments
1104 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1105 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1106
1107 // return value
1108 JavaValue r(T_OBJECT);
1109
1110 // public static String setProperty(String key, String value);
1111 JavaCalls::call_static(&r,
1112 klass,
1113 vmSymbols::setProperty_name(),
1114 vmSymbols::string_string_string_signature(),
1115 key_str,
1116 value_str,
1117 CHECK);
1118 }
1119
1120
1121 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1122 assert(thread_group.not_null(), "thread group should be specified");
1123 assert(threadObj() == NULL, "should only create Java thread object once");
1124
1125 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1126 instanceKlassHandle klass (THREAD, k);
1127 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1128
1129 java_lang_Thread::set_thread(thread_oop(), this);
1130 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1131 set_threadObj(thread_oop());
1132
1133 JavaValue result(T_VOID);
1134 if (thread_name != NULL) {
1135 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1136 // Thread gets assigned specified name and null target
1137 JavaCalls::call_special(&result,
1138 thread_oop,
1139 klass,
1140 vmSymbols::object_initializer_name(),
1141 vmSymbols::threadgroup_string_void_signature(),
1142 thread_group, // Argument 1
1143 name, // Argument 2
1144 THREAD);
1145 } else {
1146 // Thread gets assigned name "Thread-nnn" and null target
1147 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1148 JavaCalls::call_special(&result,
1149 thread_oop,
1150 klass,
1151 vmSymbols::object_initializer_name(),
1152 vmSymbols::threadgroup_runnable_void_signature(),
1153 thread_group, // Argument 1
1154 Handle(), // Argument 2
1155 THREAD);
1156 }
1157
1158
1159 if (daemon) {
1160 java_lang_Thread::set_daemon(thread_oop());
1161 }
1162
1163 if (HAS_PENDING_EXCEPTION) {
1164 return;
1165 }
1166
1167 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1168 Handle threadObj(this, this->threadObj());
1169
1170 JavaCalls::call_special(&result,
1171 thread_group,
1172 group,
1173 vmSymbols::add_method_name(),
1174 vmSymbols::thread_void_signature(),
1175 threadObj, // Arg 1
1176 THREAD);
1177
1178
1179 }
1180
1181 // NamedThread -- non-JavaThread subclasses with multiple
1182 // uniquely named instances should derive from this.
1183 NamedThread::NamedThread() : Thread() {
1184 _name = NULL;
1185 _processed_thread = NULL;
1186 }
1187
1188 NamedThread::~NamedThread() {
1189 if (_name != NULL) {
1190 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1191 _name = NULL;
1192 }
1193 }
1194
1195 void NamedThread::set_name(const char* format, ...) {
1196 guarantee(_name == NULL, "Only get to set name once.");
1197 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1198 guarantee(_name != NULL, "alloc failure");
1199 va_list ap;
1200 va_start(ap, format);
1201 jio_vsnprintf(_name, max_name_len, format, ap);
1202 va_end(ap);
1203 }
1204
1205 void NamedThread::print_on(outputStream* st) const {
1206 st->print("\"%s\" ", name());
1207 Thread::print_on(st);
1208 st->cr();
1209 }
1210
1211
1212 // ======= WatcherThread ========
1213
1214 // The watcher thread exists to simulate timer interrupts. It should
1215 // be replaced by an abstraction over whatever native support for
1216 // timer interrupts exists on the platform.
1217
1218 WatcherThread* WatcherThread::_watcher_thread = NULL;
1219 bool WatcherThread::_startable = false;
1220 volatile bool WatcherThread::_should_terminate = false;
1221
1222 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1223 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1224 if (os::create_thread(this, os::watcher_thread)) {
1225 _watcher_thread = this;
1226
1227 // Set the watcher thread to the highest OS priority which should not be
1228 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1229 // is created. The only normal thread using this priority is the reference
1230 // handler thread, which runs for very short intervals only.
1231 // If the VMThread's priority is not lower than the WatcherThread profiling
1232 // will be inaccurate.
1233 os::set_priority(this, MaxPriority);
1234 if (!DisableStartThread) {
1235 os::start_thread(this);
1236 }
1237 }
1238 }
1239
1240 int WatcherThread::sleep() const {
1241 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1242
1243 // remaining will be zero if there are no tasks,
1244 // causing the WatcherThread to sleep until a task is
1245 // enrolled
1246 int remaining = PeriodicTask::time_to_wait();
1247 int time_slept = 0;
1248
1249 // we expect this to timeout - we only ever get unparked when
1250 // we should terminate or when a new task has been enrolled
1251 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1252
1253 jlong time_before_loop = os::javaTimeNanos();
1254
1255 for (;;) {
1256 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1257 jlong now = os::javaTimeNanos();
1258
1259 if (remaining == 0) {
1260 // if we didn't have any tasks we could have waited for a long time
1261 // consider the time_slept zero and reset time_before_loop
1262 time_slept = 0;
1263 time_before_loop = now;
1264 } else {
1265 // need to recalculate since we might have new tasks in _tasks
1266 time_slept = (int) ((now - time_before_loop) / 1000000);
1267 }
1268
1269 // Change to task list or spurious wakeup of some kind
1270 if (timedout || _should_terminate) {
1271 break;
1272 }
1273
1274 remaining = PeriodicTask::time_to_wait();
1275 if (remaining == 0) {
1276 // Last task was just disenrolled so loop around and wait until
1277 // another task gets enrolled
1278 continue;
1279 }
1280
1281 remaining -= time_slept;
1282 if (remaining <= 0)
1283 break;
1284 }
1285
1286 return time_slept;
1287 }
1288
1289 void WatcherThread::run() {
1290 assert(this == watcher_thread(), "just checking");
1291
1292 this->record_stack_base_and_size();
1293 this->initialize_thread_local_storage();
1294 this->set_active_handles(JNIHandleBlock::allocate_block());
1295 while (!_should_terminate) {
1296 assert(watcher_thread() == Thread::current(), "thread consistency check");
1297 assert(watcher_thread() == this, "thread consistency check");
1298
1299 // Calculate how long it'll be until the next PeriodicTask work
1300 // should be done, and sleep that amount of time.
1301 int time_waited = sleep();
1302
1303 if (is_error_reported()) {
1304 // A fatal error has happened, the error handler(VMError::report_and_die)
1305 // should abort JVM after creating an error log file. However in some
1306 // rare cases, the error handler itself might deadlock. Here we try to
1307 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1308 //
1309 // This code is in WatcherThread because WatcherThread wakes up
1310 // periodically so the fatal error handler doesn't need to do anything;
1311 // also because the WatcherThread is less likely to crash than other
1312 // threads.
1313
1314 for (;;) {
1315 if (!ShowMessageBoxOnError
1316 && (OnError == NULL || OnError[0] == '\0')
1317 && Arguments::abort_hook() == NULL) {
1318 os::sleep(this, 2 * 60 * 1000, false);
1319 fdStream err(defaultStream::output_fd());
1320 err.print_raw_cr("# [ timer expired, abort... ]");
1321 // skip atexit/vm_exit/vm_abort hooks
1322 os::die();
1323 }
1324
1325 // Wake up 5 seconds later, the fatal handler may reset OnError or
1326 // ShowMessageBoxOnError when it is ready to abort.
1327 os::sleep(this, 5 * 1000, false);
1328 }
1329 }
1330
1331 PeriodicTask::real_time_tick(time_waited);
1332 }
1333
1334 // Signal that it is terminated
1335 {
1336 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1337 _watcher_thread = NULL;
1338 Terminator_lock->notify();
1339 }
1340
1341 // Thread destructor usually does this..
1342 ThreadLocalStorage::set_thread(NULL);
1343 }
1344
1345 void WatcherThread::start() {
1346 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1347
1348 if (watcher_thread() == NULL && _startable) {
1349 _should_terminate = false;
1350 // Create the single instance of WatcherThread
1351 new WatcherThread();
1352 }
1353 }
1354
1355 void WatcherThread::make_startable() {
1356 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1357 _startable = true;
1358 }
1359
1360 void WatcherThread::stop() {
1361 {
1362 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1363 _should_terminate = true;
1364 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1365
1366 WatcherThread* watcher = watcher_thread();
1367 if (watcher != NULL)
1368 watcher->unpark();
1369 }
1370
1371 // it is ok to take late safepoints here, if needed
1372 MutexLocker mu(Terminator_lock);
1373
1374 while (watcher_thread() != NULL) {
1375 // This wait should make safepoint checks, wait without a timeout,
1376 // and wait as a suspend-equivalent condition.
1377 //
1378 // Note: If the FlatProfiler is running, then this thread is waiting
1379 // for the WatcherThread to terminate and the WatcherThread, via the
1380 // FlatProfiler task, is waiting for the external suspend request on
1381 // this thread to complete. wait_for_ext_suspend_completion() will
1382 // eventually timeout, but that takes time. Making this wait a
1383 // suspend-equivalent condition solves that timeout problem.
1384 //
1385 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1386 Mutex::_as_suspend_equivalent_flag);
1387 }
1388 }
1389
1390 void WatcherThread::unpark() {
1391 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1392 PeriodicTask_lock->notify();
1393 }
1394
1395 void WatcherThread::print_on(outputStream* st) const {
1396 st->print("\"%s\" ", name());
1397 Thread::print_on(st);
1398 st->cr();
1399 }
1400
1401 // ======= JavaThread ========
1402
1403 // A JavaThread is a normal Java thread
1404
1405 void JavaThread::initialize() {
1406 // Initialize fields
1407
1408 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1409 set_claimed_par_id(UINT_MAX);
1410
1411 set_saved_exception_pc(NULL);
1412 set_threadObj(NULL);
1413 _anchor.clear();
1414 set_entry_point(NULL);
1415 set_jni_functions(jni_functions());
1416 set_callee_target(NULL);
1417 set_vm_result(NULL);
1418 set_vm_result_2(NULL);
1419 set_vframe_array_head(NULL);
1420 set_vframe_array_last(NULL);
1421 set_deferred_locals(NULL);
1422 set_deopt_mark(NULL);
1423 set_deopt_nmethod(NULL);
1424 clear_must_deopt_id();
1425 set_monitor_chunks(NULL);
1426 set_next(NULL);
1427 set_thread_state(_thread_new);
1428 #if INCLUDE_NMT
1429 set_recorder(NULL);
1430 #endif
1431 _terminated = _not_terminated;
1432 _privileged_stack_top = NULL;
1433 _array_for_gc = NULL;
1434 _suspend_equivalent = false;
1435 _in_deopt_handler = 0;
1436 _doing_unsafe_access = false;
1437 _stack_guard_state = stack_guard_unused;
1438 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1439 _exception_pc = 0;
1440 _exception_handler_pc = 0;
1441 _is_method_handle_return = 0;
1442 _jvmti_thread_state= NULL;
1443 _should_post_on_exceptions_flag = JNI_FALSE;
1444 _jvmti_get_loaded_classes_closure = NULL;
1445 _interp_only_mode = 0;
1446 _special_runtime_exit_condition = _no_async_condition;
1447 _pending_async_exception = NULL;
1448 _thread_stat = NULL;
1449 _thread_stat = new ThreadStatistics();
1450 _blocked_on_compilation = false;
1451 _jni_active_critical = 0;
1452 _pending_jni_exception_check_fn = NULL;
1453 _do_not_unlock_if_synchronized = false;
1454 _cached_monitor_info = NULL;
1455 _parker = Parker::Allocate(this);
1456
1457 #ifndef PRODUCT
1458 _jmp_ring_index = 0;
1459 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1460 record_jump(NULL, NULL, NULL, 0);
1461 }
1462 #endif /* PRODUCT */
1463
1464 set_thread_profiler(NULL);
1465 if (FlatProfiler::is_active()) {
1466 // This is where we would decide to either give each thread it's own profiler
1467 // or use one global one from FlatProfiler,
1468 // or up to some count of the number of profiled threads, etc.
1469 ThreadProfiler* pp = new ThreadProfiler();
1470 pp->engage();
1471 set_thread_profiler(pp);
1472 }
1473
1474 // Setup safepoint state info for this thread
1475 ThreadSafepointState::create(this);
1476
1477 debug_only(_java_call_counter = 0);
1478
1479 // JVMTI PopFrame support
1480 _popframe_condition = popframe_inactive;
1481 _popframe_preserved_args = NULL;
1482 _popframe_preserved_args_size = 0;
1483
1484 pd_initialize();
1485 }
1486
1487 #if INCLUDE_ALL_GCS
1488 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1489 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1490 #endif // INCLUDE_ALL_GCS
1491
1492 JavaThread::JavaThread(bool is_attaching_via_jni) :
1493 Thread()
1494 #if INCLUDE_ALL_GCS
1495 , _satb_mark_queue(&_satb_mark_queue_set),
1496 _dirty_card_queue(&_dirty_card_queue_set)
1497 #endif // INCLUDE_ALL_GCS
1498 {
1499 initialize();
1500 if (is_attaching_via_jni) {
1501 _jni_attach_state = _attaching_via_jni;
1502 } else {
1503 _jni_attach_state = _not_attaching_via_jni;
1504 }
1505 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1506 _safepoint_visible = false;
1507 }
1508
1509 bool JavaThread::reguard_stack(address cur_sp) {
1510 if (_stack_guard_state != stack_guard_yellow_disabled) {
1511 return true; // Stack already guarded or guard pages not needed.
1512 }
1513
1514 if (register_stack_overflow()) {
1515 // For those architectures which have separate register and
1516 // memory stacks, we must check the register stack to see if
1517 // it has overflowed.
1518 return false;
1519 }
1520
1521 // Java code never executes within the yellow zone: the latter is only
1522 // there to provoke an exception during stack banging. If java code
1523 // is executing there, either StackShadowPages should be larger, or
1524 // some exception code in c1, c2 or the interpreter isn't unwinding
1525 // when it should.
1526 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1527
1528 enable_stack_yellow_zone();
1529 return true;
1530 }
1531
1532 bool JavaThread::reguard_stack(void) {
1533 return reguard_stack(os::current_stack_pointer());
1534 }
1535
1536
1537 void JavaThread::block_if_vm_exited() {
1538 if (_terminated == _vm_exited) {
1539 // _vm_exited is set at safepoint, and Threads_lock is never released
1540 // we will block here forever
1541 Threads_lock->lock_without_safepoint_check();
1542 ShouldNotReachHere();
1543 }
1544 }
1545
1546
1547 // Remove this ifdef when C1 is ported to the compiler interface.
1548 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1549
1550 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1551 Thread()
1552 #if INCLUDE_ALL_GCS
1553 , _satb_mark_queue(&_satb_mark_queue_set),
1554 _dirty_card_queue(&_dirty_card_queue_set)
1555 #endif // INCLUDE_ALL_GCS
1556 {
1557 if (TraceThreadEvents) {
1558 tty->print_cr("creating thread %p", this);
1559 }
1560 initialize();
1561 _jni_attach_state = _not_attaching_via_jni;
1562 set_entry_point(entry_point);
1563 // Create the native thread itself.
1564 // %note runtime_23
1565 os::ThreadType thr_type = os::java_thread;
1566 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1567 os::java_thread;
1568 os::create_thread(this, thr_type, stack_sz);
1569 _safepoint_visible = false;
1570 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1571 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1572 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1573 // the exception consists of creating the exception object & initializing it, initialization
1574 // will leave the VM via a JavaCall and then all locks must be unlocked).
1575 //
1576 // The thread is still suspended when we reach here. Thread must be explicit started
1577 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1578 // by calling Threads:add. The reason why this is not done here, is because the thread
1579 // object must be fully initialized (take a look at JVM_Start)
1580 }
1581
1582 JavaThread::~JavaThread() {
1583 if (TraceThreadEvents) {
1584 tty->print_cr("terminate thread %p", this);
1585 }
1586
1587 // By now, this thread should already be invisible to safepoint,
1588 // and its per-thread recorder also collected.
1589 assert(!is_safepoint_visible(), "wrong state");
1590 #if INCLUDE_NMT
1591 assert(get_recorder() == NULL, "Already collected");
1592 #endif // INCLUDE_NMT
1593
1594 // JSR166 -- return the parker to the free list
1595 Parker::Release(_parker);
1596 _parker = NULL;
1597
1598 // Free any remaining previous UnrollBlock
1599 vframeArray* old_array = vframe_array_last();
1600
1601 if (old_array != NULL) {
1602 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1603 old_array->set_unroll_block(NULL);
1604 delete old_info;
1605 delete old_array;
1606 }
1607
1608 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1609 if (deferred != NULL) {
1610 // This can only happen if thread is destroyed before deoptimization occurs.
1611 assert(deferred->length() != 0, "empty array!");
1612 do {
1613 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1614 deferred->remove_at(0);
1615 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1616 delete dlv;
1617 } while (deferred->length() != 0);
1618 delete deferred;
1619 }
1620
1621 // All Java related clean up happens in exit
1622 ThreadSafepointState::destroy(this);
1623 if (_thread_profiler != NULL) delete _thread_profiler;
1624 if (_thread_stat != NULL) delete _thread_stat;
1625 }
1626
1627
1628 // The first routine called by a new Java thread
1629 void JavaThread::run() {
1630 // initialize thread-local alloc buffer related fields
1631 this->initialize_tlab();
1632
1633 // used to test validity of stack trace backs
1634 this->record_base_of_stack_pointer();
1635
1636 // Record real stack base and size.
1637 this->record_stack_base_and_size();
1638
1639 // Initialize thread local storage; set before calling MutexLocker
1640 this->initialize_thread_local_storage();
1641
1642 this->create_stack_guard_pages();
1643
1644 this->cache_global_variables();
1645
1646 // Thread is now sufficient initialized to be handled by the safepoint code as being
1647 // in the VM. Change thread state from _thread_new to _thread_in_vm
1648 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1649
1650 assert(JavaThread::current() == this, "sanity check");
1651 assert(!Thread::current()->owns_locks(), "sanity check");
1652
1653 DTRACE_THREAD_PROBE(start, this);
1654
1655 // This operation might block. We call that after all safepoint checks for a new thread has
1656 // been completed.
1657 this->set_active_handles(JNIHandleBlock::allocate_block());
1658
1659 if (JvmtiExport::should_post_thread_life()) {
1660 JvmtiExport::post_thread_start(this);
1661 }
1662
1663 EventThreadStart event;
1664 if (event.should_commit()) {
1665 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1666 event.commit();
1667 }
1668
1669 // We call another function to do the rest so we are sure that the stack addresses used
1670 // from there will be lower than the stack base just computed
1671 thread_main_inner();
1672
1673 // Note, thread is no longer valid at this point!
1674 }
1675
1676
1677 void JavaThread::thread_main_inner() {
1678 assert(JavaThread::current() == this, "sanity check");
1679 assert(this->threadObj() != NULL, "just checking");
1680
1681 // Execute thread entry point unless this thread has a pending exception
1682 // or has been stopped before starting.
1683 // Note: Due to JVM_StopThread we can have pending exceptions already!
1684 if (!this->has_pending_exception() &&
1685 !java_lang_Thread::is_stillborn(this->threadObj())) {
1686 {
1687 ResourceMark rm(this);
1688 this->set_native_thread_name(this->get_thread_name());
1689 }
1690 HandleMark hm(this);
1691 this->entry_point()(this, this);
1692 }
1693
1694 DTRACE_THREAD_PROBE(stop, this);
1695
1696 this->exit(false);
1697 delete this;
1698 }
1699
1700
1701 static void ensure_join(JavaThread* thread) {
1702 // We do not need to grap the Threads_lock, since we are operating on ourself.
1703 Handle threadObj(thread, thread->threadObj());
1704 assert(threadObj.not_null(), "java thread object must exist");
1705 ObjectLocker lock(threadObj, thread);
1706 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1707 thread->clear_pending_exception();
1708 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1709 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1710 // Clear the native thread instance - this makes isAlive return false and allows the join()
1711 // to complete once we've done the notify_all below
1712 java_lang_Thread::set_thread(threadObj(), NULL);
1713 lock.notify_all(thread);
1714 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1715 thread->clear_pending_exception();
1716 }
1717
1718
1719 // For any new cleanup additions, please check to see if they need to be applied to
1720 // cleanup_failed_attach_current_thread as well.
1721 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1722 assert(this == JavaThread::current(), "thread consistency check");
1723
1724 HandleMark hm(this);
1725 Handle uncaught_exception(this, this->pending_exception());
1726 this->clear_pending_exception();
1727 Handle threadObj(this, this->threadObj());
1728 assert(threadObj.not_null(), "Java thread object should be created");
1729
1730 if (get_thread_profiler() != NULL) {
1731 get_thread_profiler()->disengage();
1732 ResourceMark rm;
1733 get_thread_profiler()->print(get_thread_name());
1734 }
1735
1736
1737 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1738 {
1739 EXCEPTION_MARK;
1740
1741 CLEAR_PENDING_EXCEPTION;
1742 }
1743 if (!destroy_vm) {
1744 if (uncaught_exception.not_null()) {
1745 EXCEPTION_MARK;
1746 // Call method Thread.dispatchUncaughtException().
1747 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1748 JavaValue result(T_VOID);
1749 JavaCalls::call_virtual(&result,
1750 threadObj, thread_klass,
1751 vmSymbols::dispatchUncaughtException_name(),
1752 vmSymbols::throwable_void_signature(),
1753 uncaught_exception,
1754 THREAD);
1755 if (HAS_PENDING_EXCEPTION) {
1756 ResourceMark rm(this);
1757 jio_fprintf(defaultStream::error_stream(),
1758 "\nException: %s thrown from the UncaughtExceptionHandler"
1759 " in thread \"%s\"\n",
1760 pending_exception()->klass()->external_name(),
1761 get_thread_name());
1762 CLEAR_PENDING_EXCEPTION;
1763 }
1764 }
1765
1766 // Called before the java thread exit since we want to read info
1767 // from java_lang_Thread object
1768 EventThreadEnd event;
1769 if (event.should_commit()) {
1770 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1771 event.commit();
1772 }
1773
1774 // Call after last event on thread
1775 EVENT_THREAD_EXIT(this);
1776
1777 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1778 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1779 // is deprecated anyhow.
1780 if (!is_Compiler_thread()) {
1781 int count = 3;
1782 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1783 EXCEPTION_MARK;
1784 JavaValue result(T_VOID);
1785 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1786 JavaCalls::call_virtual(&result,
1787 threadObj, thread_klass,
1788 vmSymbols::exit_method_name(),
1789 vmSymbols::void_method_signature(),
1790 THREAD);
1791 CLEAR_PENDING_EXCEPTION;
1792 }
1793 }
1794 // notify JVMTI
1795 if (JvmtiExport::should_post_thread_life()) {
1796 JvmtiExport::post_thread_end(this);
1797 }
1798
1799 // We have notified the agents that we are exiting, before we go on,
1800 // we must check for a pending external suspend request and honor it
1801 // in order to not surprise the thread that made the suspend request.
1802 while (true) {
1803 {
1804 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1805 if (!is_external_suspend()) {
1806 set_terminated(_thread_exiting);
1807 ThreadService::current_thread_exiting(this);
1808 break;
1809 }
1810 // Implied else:
1811 // Things get a little tricky here. We have a pending external
1812 // suspend request, but we are holding the SR_lock so we
1813 // can't just self-suspend. So we temporarily drop the lock
1814 // and then self-suspend.
1815 }
1816
1817 ThreadBlockInVM tbivm(this);
1818 java_suspend_self();
1819
1820 // We're done with this suspend request, but we have to loop around
1821 // and check again. Eventually we will get SR_lock without a pending
1822 // external suspend request and will be able to mark ourselves as
1823 // exiting.
1824 }
1825 // no more external suspends are allowed at this point
1826 } else {
1827 // before_exit() has already posted JVMTI THREAD_END events
1828 }
1829
1830 // Notify waiters on thread object. This has to be done after exit() is called
1831 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1832 // group should have the destroyed bit set before waiters are notified).
1833 ensure_join(this);
1834 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1835
1836 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1837 // held by this thread must be released. A detach operation must only
1838 // get here if there are no Java frames on the stack. Therefore, any
1839 // owned monitors at this point MUST be JNI-acquired monitors which are
1840 // pre-inflated and in the monitor cache.
1841 //
1842 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1843 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1844 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1845 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1846 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1847 }
1848
1849 // These things needs to be done while we are still a Java Thread. Make sure that thread
1850 // is in a consistent state, in case GC happens
1851 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1852
1853 if (active_handles() != NULL) {
1854 JNIHandleBlock* block = active_handles();
1855 set_active_handles(NULL);
1856 JNIHandleBlock::release_block(block);
1857 }
1858
1859 if (free_handle_block() != NULL) {
1860 JNIHandleBlock* block = free_handle_block();
1861 set_free_handle_block(NULL);
1862 JNIHandleBlock::release_block(block);
1863 }
1864
1865 // These have to be removed while this is still a valid thread.
1866 remove_stack_guard_pages();
1867
1868 if (UseTLAB) {
1869 tlab().make_parsable(true); // retire TLAB
1870 }
1871
1872 if (JvmtiEnv::environments_might_exist()) {
1873 JvmtiExport::cleanup_thread(this);
1874 }
1875
1876 // We must flush any deferred card marks before removing a thread from
1877 // the list of active threads.
1878 Universe::heap()->flush_deferred_store_barrier(this);
1879 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1880
1881 #if INCLUDE_ALL_GCS
1882 // We must flush the G1-related buffers before removing a thread
1883 // from the list of active threads. We must do this after any deferred
1884 // card marks have been flushed (above) so that any entries that are
1885 // added to the thread's dirty card queue as a result are not lost.
1886 if (UseG1GC) {
1887 flush_barrier_queues();
1888 }
1889 #endif // INCLUDE_ALL_GCS
1890
1891 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1892 Threads::remove(this);
1893 }
1894
1895 #if INCLUDE_ALL_GCS
1896 // Flush G1-related queues.
1897 void JavaThread::flush_barrier_queues() {
1898 satb_mark_queue().flush();
1899 dirty_card_queue().flush();
1900 }
1901
1902 void JavaThread::initialize_queues() {
1903 assert(!SafepointSynchronize::is_at_safepoint(),
1904 "we should not be at a safepoint");
1905
1906 ObjPtrQueue& satb_queue = satb_mark_queue();
1907 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1908 // The SATB queue should have been constructed with its active
1909 // field set to false.
1910 assert(!satb_queue.is_active(), "SATB queue should not be active");
1911 assert(satb_queue.is_empty(), "SATB queue should be empty");
1912 // If we are creating the thread during a marking cycle, we should
1913 // set the active field of the SATB queue to true.
1914 if (satb_queue_set.is_active()) {
1915 satb_queue.set_active(true);
1916 }
1917
1918 DirtyCardQueue& dirty_queue = dirty_card_queue();
1919 // The dirty card queue should have been constructed with its
1920 // active field set to true.
1921 assert(dirty_queue.is_active(), "dirty card queue should be active");
1922 }
1923 #endif // INCLUDE_ALL_GCS
1924
1925 void JavaThread::cleanup_failed_attach_current_thread() {
1926 if (get_thread_profiler() != NULL) {
1927 get_thread_profiler()->disengage();
1928 ResourceMark rm;
1929 get_thread_profiler()->print(get_thread_name());
1930 }
1931
1932 if (active_handles() != NULL) {
1933 JNIHandleBlock* block = active_handles();
1934 set_active_handles(NULL);
1935 JNIHandleBlock::release_block(block);
1936 }
1937
1938 if (free_handle_block() != NULL) {
1939 JNIHandleBlock* block = free_handle_block();
1940 set_free_handle_block(NULL);
1941 JNIHandleBlock::release_block(block);
1942 }
1943
1944 // These have to be removed while this is still a valid thread.
1945 remove_stack_guard_pages();
1946
1947 if (UseTLAB) {
1948 tlab().make_parsable(true); // retire TLAB, if any
1949 }
1950
1951 #if INCLUDE_ALL_GCS
1952 if (UseG1GC) {
1953 flush_barrier_queues();
1954 }
1955 #endif // INCLUDE_ALL_GCS
1956
1957 Threads::remove(this);
1958 delete this;
1959 }
1960
1961
1962
1963
1964 JavaThread* JavaThread::active() {
1965 Thread* thread = ThreadLocalStorage::thread();
1966 assert(thread != NULL, "just checking");
1967 if (thread->is_Java_thread()) {
1968 return (JavaThread*) thread;
1969 } else {
1970 assert(thread->is_VM_thread(), "this must be a vm thread");
1971 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1972 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1973 assert(ret->is_Java_thread(), "must be a Java thread");
1974 return ret;
1975 }
1976 }
1977
1978 bool JavaThread::is_lock_owned(address adr) const {
1979 if (Thread::is_lock_owned(adr)) return true;
1980
1981 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1982 if (chunk->contains(adr)) return true;
1983 }
1984
1985 return false;
1986 }
1987
1988
1989 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1990 chunk->set_next(monitor_chunks());
1991 set_monitor_chunks(chunk);
1992 }
1993
1994 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1995 guarantee(monitor_chunks() != NULL, "must be non empty");
1996 if (monitor_chunks() == chunk) {
1997 set_monitor_chunks(chunk->next());
1998 } else {
1999 MonitorChunk* prev = monitor_chunks();
2000 while (prev->next() != chunk) prev = prev->next();
2001 prev->set_next(chunk->next());
2002 }
2003 }
2004
2005 // JVM support.
2006
2007 // Note: this function shouldn't block if it's called in
2008 // _thread_in_native_trans state (such as from
2009 // check_special_condition_for_native_trans()).
2010 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2011
2012 if (has_last_Java_frame() && has_async_condition()) {
2013 // If we are at a polling page safepoint (not a poll return)
2014 // then we must defer async exception because live registers
2015 // will be clobbered by the exception path. Poll return is
2016 // ok because the call we a returning from already collides
2017 // with exception handling registers and so there is no issue.
2018 // (The exception handling path kills call result registers but
2019 // this is ok since the exception kills the result anyway).
2020
2021 if (is_at_poll_safepoint()) {
2022 // if the code we are returning to has deoptimized we must defer
2023 // the exception otherwise live registers get clobbered on the
2024 // exception path before deoptimization is able to retrieve them.
2025 //
2026 RegisterMap map(this, false);
2027 frame caller_fr = last_frame().sender(&map);
2028 assert(caller_fr.is_compiled_frame(), "what?");
2029 if (caller_fr.is_deoptimized_frame()) {
2030 if (TraceExceptions) {
2031 ResourceMark rm;
2032 tty->print_cr("deferred async exception at compiled safepoint");
2033 }
2034 return;
2035 }
2036 }
2037 }
2038
2039 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2040 if (condition == _no_async_condition) {
2041 // Conditions have changed since has_special_runtime_exit_condition()
2042 // was called:
2043 // - if we were here only because of an external suspend request,
2044 // then that was taken care of above (or cancelled) so we are done
2045 // - if we were here because of another async request, then it has
2046 // been cleared between the has_special_runtime_exit_condition()
2047 // and now so again we are done
2048 return;
2049 }
2050
2051 // Check for pending async. exception
2052 if (_pending_async_exception != NULL) {
2053 // Only overwrite an already pending exception, if it is not a threadDeath.
2054 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2055
2056 // We cannot call Exceptions::_throw(...) here because we cannot block
2057 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2058
2059 if (TraceExceptions) {
2060 ResourceMark rm;
2061 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2062 if (has_last_Java_frame()) {
2063 frame f = last_frame();
2064 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2065 }
2066 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2067 }
2068 _pending_async_exception = NULL;
2069 clear_has_async_exception();
2070 }
2071 }
2072
2073 if (check_unsafe_error &&
2074 condition == _async_unsafe_access_error && !has_pending_exception()) {
2075 condition = _no_async_condition; // done
2076 switch (thread_state()) {
2077 case _thread_in_vm:
2078 {
2079 JavaThread* THREAD = this;
2080 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2081 }
2082 case _thread_in_native:
2083 {
2084 ThreadInVMfromNative tiv(this);
2085 JavaThread* THREAD = this;
2086 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2087 }
2088 case _thread_in_Java:
2089 {
2090 ThreadInVMfromJava tiv(this);
2091 JavaThread* THREAD = this;
2092 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2093 }
2094 default:
2095 ShouldNotReachHere();
2096 }
2097 }
2098
2099 assert(condition == _no_async_condition || has_pending_exception() ||
2100 (!check_unsafe_error && condition == _async_unsafe_access_error),
2101 "must have handled the async condition, if no exception");
2102 }
2103
2104 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2105 //
2106 // Check for pending external suspend. Internal suspend requests do
2107 // not use handle_special_runtime_exit_condition().
2108 // If JNIEnv proxies are allowed, don't self-suspend if the target
2109 // thread is not the current thread. In older versions of jdbx, jdbx
2110 // threads could call into the VM with another thread's JNIEnv so we
2111 // can be here operating on behalf of a suspended thread (4432884).
2112 bool do_self_suspend = is_external_suspend_with_lock();
2113 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2114 //
2115 // Because thread is external suspended the safepoint code will count
2116 // thread as at a safepoint. This can be odd because we can be here
2117 // as _thread_in_Java which would normally transition to _thread_blocked
2118 // at a safepoint. We would like to mark the thread as _thread_blocked
2119 // before calling java_suspend_self like all other callers of it but
2120 // we must then observe proper safepoint protocol. (We can't leave
2121 // _thread_blocked with a safepoint in progress). However we can be
2122 // here as _thread_in_native_trans so we can't use a normal transition
2123 // constructor/destructor pair because they assert on that type of
2124 // transition. We could do something like:
2125 //
2126 // JavaThreadState state = thread_state();
2127 // set_thread_state(_thread_in_vm);
2128 // {
2129 // ThreadBlockInVM tbivm(this);
2130 // java_suspend_self()
2131 // }
2132 // set_thread_state(_thread_in_vm_trans);
2133 // if (safepoint) block;
2134 // set_thread_state(state);
2135 //
2136 // but that is pretty messy. Instead we just go with the way the
2137 // code has worked before and note that this is the only path to
2138 // java_suspend_self that doesn't put the thread in _thread_blocked
2139 // mode.
2140
2141 frame_anchor()->make_walkable(this);
2142 java_suspend_self();
2143
2144 // We might be here for reasons in addition to the self-suspend request
2145 // so check for other async requests.
2146 }
2147
2148 if (check_asyncs) {
2149 check_and_handle_async_exceptions();
2150 }
2151 }
2152
2153 void JavaThread::send_thread_stop(oop java_throwable) {
2154 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2155 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2156 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2157
2158 // Do not throw asynchronous exceptions against the compiler thread
2159 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2160 if (is_Compiler_thread()) return;
2161
2162 {
2163 // Actually throw the Throwable against the target Thread - however
2164 // only if there is no thread death exception installed already.
2165 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2166 // If the topmost frame is a runtime stub, then we are calling into
2167 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2168 // must deoptimize the caller before continuing, as the compiled exception handler table
2169 // may not be valid
2170 if (has_last_Java_frame()) {
2171 frame f = last_frame();
2172 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2173 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2174 RegisterMap reg_map(this, UseBiasedLocking);
2175 frame compiled_frame = f.sender(®_map);
2176 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2177 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2178 }
2179 }
2180 }
2181
2182 // Set async. pending exception in thread.
2183 set_pending_async_exception(java_throwable);
2184
2185 if (TraceExceptions) {
2186 ResourceMark rm;
2187 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2188 }
2189 // for AbortVMOnException flag
2190 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2191 }
2192 }
2193
2194
2195 // Interrupt thread so it will wake up from a potential wait()
2196 Thread::interrupt(this);
2197 }
2198
2199 // External suspension mechanism.
2200 //
2201 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2202 // to any VM_locks and it is at a transition
2203 // Self-suspension will happen on the transition out of the vm.
2204 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2205 //
2206 // Guarantees on return:
2207 // + Target thread will not execute any new bytecode (that's why we need to
2208 // force a safepoint)
2209 // + Target thread will not enter any new monitors
2210 //
2211 void JavaThread::java_suspend() {
2212 { MutexLocker mu(Threads_lock);
2213 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2214 return;
2215 }
2216 }
2217
2218 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2219 if (!is_external_suspend()) {
2220 // a racing resume has cancelled us; bail out now
2221 return;
2222 }
2223
2224 // suspend is done
2225 uint32_t debug_bits = 0;
2226 // Warning: is_ext_suspend_completed() may temporarily drop the
2227 // SR_lock to allow the thread to reach a stable thread state if
2228 // it is currently in a transient thread state.
2229 if (is_ext_suspend_completed(false /* !called_by_wait */,
2230 SuspendRetryDelay, &debug_bits) ) {
2231 return;
2232 }
2233 }
2234
2235 VM_ForceSafepoint vm_suspend;
2236 VMThread::execute(&vm_suspend);
2237 }
2238
2239 // Part II of external suspension.
2240 // A JavaThread self suspends when it detects a pending external suspend
2241 // request. This is usually on transitions. It is also done in places
2242 // where continuing to the next transition would surprise the caller,
2243 // e.g., monitor entry.
2244 //
2245 // Returns the number of times that the thread self-suspended.
2246 //
2247 // Note: DO NOT call java_suspend_self() when you just want to block current
2248 // thread. java_suspend_self() is the second stage of cooperative
2249 // suspension for external suspend requests and should only be used
2250 // to complete an external suspend request.
2251 //
2252 int JavaThread::java_suspend_self() {
2253 int ret = 0;
2254
2255 // we are in the process of exiting so don't suspend
2256 if (is_exiting()) {
2257 clear_external_suspend();
2258 return ret;
2259 }
2260
2261 assert(_anchor.walkable() ||
2262 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2263 "must have walkable stack");
2264
2265 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2266
2267 assert(!this->is_ext_suspended(),
2268 "a thread trying to self-suspend should not already be suspended");
2269
2270 if (this->is_suspend_equivalent()) {
2271 // If we are self-suspending as a result of the lifting of a
2272 // suspend equivalent condition, then the suspend_equivalent
2273 // flag is not cleared until we set the ext_suspended flag so
2274 // that wait_for_ext_suspend_completion() returns consistent
2275 // results.
2276 this->clear_suspend_equivalent();
2277 }
2278
2279 // A racing resume may have cancelled us before we grabbed SR_lock
2280 // above. Or another external suspend request could be waiting for us
2281 // by the time we return from SR_lock()->wait(). The thread
2282 // that requested the suspension may already be trying to walk our
2283 // stack and if we return now, we can change the stack out from under
2284 // it. This would be a "bad thing (TM)" and cause the stack walker
2285 // to crash. We stay self-suspended until there are no more pending
2286 // external suspend requests.
2287 while (is_external_suspend()) {
2288 ret++;
2289 this->set_ext_suspended();
2290
2291 // _ext_suspended flag is cleared by java_resume()
2292 while (is_ext_suspended()) {
2293 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2294 }
2295 }
2296
2297 return ret;
2298 }
2299
2300 #ifdef ASSERT
2301 // verify the JavaThread has not yet been published in the Threads::list, and
2302 // hence doesn't need protection from concurrent access at this stage
2303 void JavaThread::verify_not_published() {
2304 if (!Threads_lock->owned_by_self()) {
2305 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2306 assert(!Threads::includes(this),
2307 "java thread shouldn't have been published yet!");
2308 }
2309 else {
2310 assert(!Threads::includes(this),
2311 "java thread shouldn't have been published yet!");
2312 }
2313 }
2314 #endif
2315
2316 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2317 // progress or when _suspend_flags is non-zero.
2318 // Current thread needs to self-suspend if there is a suspend request and/or
2319 // block if a safepoint is in progress.
2320 // Async exception ISN'T checked.
2321 // Note only the ThreadInVMfromNative transition can call this function
2322 // directly and when thread state is _thread_in_native_trans
2323 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2324 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2325
2326 JavaThread *curJT = JavaThread::current();
2327 bool do_self_suspend = thread->is_external_suspend();
2328
2329 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2330
2331 // If JNIEnv proxies are allowed, don't self-suspend if the target
2332 // thread is not the current thread. In older versions of jdbx, jdbx
2333 // threads could call into the VM with another thread's JNIEnv so we
2334 // can be here operating on behalf of a suspended thread (4432884).
2335 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2336 JavaThreadState state = thread->thread_state();
2337
2338 // We mark this thread_blocked state as a suspend-equivalent so
2339 // that a caller to is_ext_suspend_completed() won't be confused.
2340 // The suspend-equivalent state is cleared by java_suspend_self().
2341 thread->set_suspend_equivalent();
2342
2343 // If the safepoint code sees the _thread_in_native_trans state, it will
2344 // wait until the thread changes to other thread state. There is no
2345 // guarantee on how soon we can obtain the SR_lock and complete the
2346 // self-suspend request. It would be a bad idea to let safepoint wait for
2347 // too long. Temporarily change the state to _thread_blocked to
2348 // let the VM thread know that this thread is ready for GC. The problem
2349 // of changing thread state is that safepoint could happen just after
2350 // java_suspend_self() returns after being resumed, and VM thread will
2351 // see the _thread_blocked state. We must check for safepoint
2352 // after restoring the state and make sure we won't leave while a safepoint
2353 // is in progress.
2354 thread->set_thread_state(_thread_blocked);
2355 thread->java_suspend_self();
2356 thread->set_thread_state(state);
2357 // Make sure new state is seen by VM thread
2358 if (os::is_MP()) {
2359 if (UseMembar) {
2360 // Force a fence between the write above and read below
2361 OrderAccess::fence();
2362 } else {
2363 // Must use this rather than serialization page in particular on Windows
2364 InterfaceSupport::serialize_memory(thread);
2365 }
2366 }
2367 }
2368
2369 if (SafepointSynchronize::do_call_back()) {
2370 // If we are safepointing, then block the caller which may not be
2371 // the same as the target thread (see above).
2372 SafepointSynchronize::block(curJT);
2373 }
2374
2375 if (thread->is_deopt_suspend()) {
2376 thread->clear_deopt_suspend();
2377 RegisterMap map(thread, false);
2378 frame f = thread->last_frame();
2379 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2380 f = f.sender(&map);
2381 }
2382 if (f.id() == thread->must_deopt_id()) {
2383 thread->clear_must_deopt_id();
2384 f.deoptimize(thread);
2385 } else {
2386 fatal("missed deoptimization!");
2387 }
2388 }
2389 }
2390
2391 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2392 // progress or when _suspend_flags is non-zero.
2393 // Current thread needs to self-suspend if there is a suspend request and/or
2394 // block if a safepoint is in progress.
2395 // Also check for pending async exception (not including unsafe access error).
2396 // Note only the native==>VM/Java barriers can call this function and when
2397 // thread state is _thread_in_native_trans.
2398 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2399 check_safepoint_and_suspend_for_native_trans(thread);
2400
2401 if (thread->has_async_exception()) {
2402 // We are in _thread_in_native_trans state, don't handle unsafe
2403 // access error since that may block.
2404 thread->check_and_handle_async_exceptions(false);
2405 }
2406 }
2407
2408 // This is a variant of the normal
2409 // check_special_condition_for_native_trans with slightly different
2410 // semantics for use by critical native wrappers. It does all the
2411 // normal checks but also performs the transition back into
2412 // thread_in_Java state. This is required so that critical natives
2413 // can potentially block and perform a GC if they are the last thread
2414 // exiting the GC_locker.
2415 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2416 check_special_condition_for_native_trans(thread);
2417
2418 // Finish the transition
2419 thread->set_thread_state(_thread_in_Java);
2420
2421 if (thread->do_critical_native_unlock()) {
2422 ThreadInVMfromJavaNoAsyncException tiv(thread);
2423 GC_locker::unlock_critical(thread);
2424 thread->clear_critical_native_unlock();
2425 }
2426 }
2427
2428 // We need to guarantee the Threads_lock here, since resumes are not
2429 // allowed during safepoint synchronization
2430 // Can only resume from an external suspension
2431 void JavaThread::java_resume() {
2432 assert_locked_or_safepoint(Threads_lock);
2433
2434 // Sanity check: thread is gone, has started exiting or the thread
2435 // was not externally suspended.
2436 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2437 return;
2438 }
2439
2440 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2441
2442 clear_external_suspend();
2443
2444 if (is_ext_suspended()) {
2445 clear_ext_suspended();
2446 SR_lock()->notify_all();
2447 }
2448 }
2449
2450 void JavaThread::create_stack_guard_pages() {
2451 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2452 address low_addr = stack_base() - stack_size();
2453 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2454
2455 int allocate = os::allocate_stack_guard_pages();
2456 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2457
2458 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2459 warning("Attempt to allocate stack guard pages failed.");
2460 return;
2461 }
2462
2463 if (os::guard_memory((char *) low_addr, len)) {
2464 _stack_guard_state = stack_guard_enabled;
2465 } else {
2466 warning("Attempt to protect stack guard pages failed.");
2467 if (os::uncommit_memory((char *) low_addr, len)) {
2468 warning("Attempt to deallocate stack guard pages failed.");
2469 }
2470 }
2471 }
2472
2473 void JavaThread::remove_stack_guard_pages() {
2474 assert(Thread::current() == this, "from different thread");
2475 if (_stack_guard_state == stack_guard_unused) return;
2476 address low_addr = stack_base() - stack_size();
2477 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2478
2479 if (os::allocate_stack_guard_pages()) {
2480 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2481 _stack_guard_state = stack_guard_unused;
2482 } else {
2483 warning("Attempt to deallocate stack guard pages failed.");
2484 }
2485 } else {
2486 if (_stack_guard_state == stack_guard_unused) return;
2487 if (os::unguard_memory((char *) low_addr, len)) {
2488 _stack_guard_state = stack_guard_unused;
2489 } else {
2490 warning("Attempt to unprotect stack guard pages failed.");
2491 }
2492 }
2493 }
2494
2495 void JavaThread::enable_stack_yellow_zone() {
2496 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2497 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2498
2499 // The base notation is from the stacks point of view, growing downward.
2500 // We need to adjust it to work correctly with guard_memory()
2501 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2502
2503 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2504 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2505
2506 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2507 _stack_guard_state = stack_guard_enabled;
2508 } else {
2509 warning("Attempt to guard stack yellow zone failed.");
2510 }
2511 enable_register_stack_guard();
2512 }
2513
2514 void JavaThread::disable_stack_yellow_zone() {
2515 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2516 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2517
2518 // Simply return if called for a thread that does not use guard pages.
2519 if (_stack_guard_state == stack_guard_unused) return;
2520
2521 // The base notation is from the stacks point of view, growing downward.
2522 // We need to adjust it to work correctly with guard_memory()
2523 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2524
2525 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2526 _stack_guard_state = stack_guard_yellow_disabled;
2527 } else {
2528 warning("Attempt to unguard stack yellow zone failed.");
2529 }
2530 disable_register_stack_guard();
2531 }
2532
2533 void JavaThread::enable_stack_red_zone() {
2534 // The base notation is from the stacks point of view, growing downward.
2535 // We need to adjust it to work correctly with guard_memory()
2536 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2537 address base = stack_red_zone_base() - stack_red_zone_size();
2538
2539 guarantee(base < stack_base(), "Error calculating stack red zone");
2540 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2541
2542 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2543 warning("Attempt to guard stack red zone failed.");
2544 }
2545 }
2546
2547 void JavaThread::disable_stack_red_zone() {
2548 // The base notation is from the stacks point of view, growing downward.
2549 // We need to adjust it to work correctly with guard_memory()
2550 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2551 address base = stack_red_zone_base() - stack_red_zone_size();
2552 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2553 warning("Attempt to unguard stack red zone failed.");
2554 }
2555 }
2556
2557 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2558 // ignore is there is no stack
2559 if (!has_last_Java_frame()) return;
2560 // traverse the stack frames. Starts from top frame.
2561 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2562 frame* fr = fst.current();
2563 f(fr, fst.register_map());
2564 }
2565 }
2566
2567
2568 #ifndef PRODUCT
2569 // Deoptimization
2570 // Function for testing deoptimization
2571 void JavaThread::deoptimize() {
2572 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2573 StackFrameStream fst(this, UseBiasedLocking);
2574 bool deopt = false; // Dump stack only if a deopt actually happens.
2575 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2576 // Iterate over all frames in the thread and deoptimize
2577 for (; !fst.is_done(); fst.next()) {
2578 if (fst.current()->can_be_deoptimized()) {
2579
2580 if (only_at) {
2581 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2582 // consists of comma or carriage return separated numbers so
2583 // search for the current bci in that string.
2584 address pc = fst.current()->pc();
2585 nmethod* nm = (nmethod*) fst.current()->cb();
2586 ScopeDesc* sd = nm->scope_desc_at( pc);
2587 char buffer[8];
2588 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2589 size_t len = strlen(buffer);
2590 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2591 while (found != NULL) {
2592 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2593 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2594 // Check that the bci found is bracketed by terminators.
2595 break;
2596 }
2597 found = strstr(found + 1, buffer);
2598 }
2599 if (!found) {
2600 continue;
2601 }
2602 }
2603
2604 if (DebugDeoptimization && !deopt) {
2605 deopt = true; // One-time only print before deopt
2606 tty->print_cr("[BEFORE Deoptimization]");
2607 trace_frames();
2608 trace_stack();
2609 }
2610 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2611 }
2612 }
2613
2614 if (DebugDeoptimization && deopt) {
2615 tty->print_cr("[AFTER Deoptimization]");
2616 trace_frames();
2617 }
2618 }
2619
2620
2621 // Make zombies
2622 void JavaThread::make_zombies() {
2623 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2624 if (fst.current()->can_be_deoptimized()) {
2625 // it is a Java nmethod
2626 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2627 nm->make_not_entrant();
2628 }
2629 }
2630 }
2631 #endif // PRODUCT
2632
2633
2634 void JavaThread::deoptimized_wrt_marked_nmethods() {
2635 if (!has_last_Java_frame()) return;
2636 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2637 StackFrameStream fst(this, UseBiasedLocking);
2638 for (; !fst.is_done(); fst.next()) {
2639 if (fst.current()->should_be_deoptimized()) {
2640 if (LogCompilation && xtty != NULL) {
2641 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2642 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2643 this->name(), nm != NULL ? nm->compile_id() : -1);
2644 }
2645
2646 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2647 }
2648 }
2649 }
2650
2651
2652 // GC support
2653 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2654
2655 void JavaThread::gc_epilogue() {
2656 frames_do(frame_gc_epilogue);
2657 }
2658
2659
2660 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2661
2662 void JavaThread::gc_prologue() {
2663 frames_do(frame_gc_prologue);
2664 }
2665
2666 // If the caller is a NamedThread, then remember, in the current scope,
2667 // the given JavaThread in its _processed_thread field.
2668 class RememberProcessedThread: public StackObj {
2669 NamedThread* _cur_thr;
2670 public:
2671 RememberProcessedThread(JavaThread* jthr) {
2672 Thread* thread = Thread::current();
2673 if (thread->is_Named_thread()) {
2674 _cur_thr = (NamedThread *)thread;
2675 _cur_thr->set_processed_thread(jthr);
2676 } else {
2677 _cur_thr = NULL;
2678 }
2679 }
2680
2681 ~RememberProcessedThread() {
2682 if (_cur_thr) {
2683 _cur_thr->set_processed_thread(NULL);
2684 }
2685 }
2686 };
2687
2688 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2689 // Verify that the deferred card marks have been flushed.
2690 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2691
2692 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2693 // since there may be more than one thread using each ThreadProfiler.
2694
2695 // Traverse the GCHandles
2696 Thread::oops_do(f, cld_f, cf);
2697
2698 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2699 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2700
2701 if (has_last_Java_frame()) {
2702 // Record JavaThread to GC thread
2703 RememberProcessedThread rpt(this);
2704
2705 // Traverse the privileged stack
2706 if (_privileged_stack_top != NULL) {
2707 _privileged_stack_top->oops_do(f);
2708 }
2709
2710 // traverse the registered growable array
2711 if (_array_for_gc != NULL) {
2712 for (int index = 0; index < _array_for_gc->length(); index++) {
2713 f->do_oop(_array_for_gc->adr_at(index));
2714 }
2715 }
2716
2717 // Traverse the monitor chunks
2718 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2719 chunk->oops_do(f);
2720 }
2721
2722 // Traverse the execution stack
2723 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2724 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2725 }
2726 }
2727
2728 // callee_target is never live across a gc point so NULL it here should
2729 // it still contain a methdOop.
2730
2731 set_callee_target(NULL);
2732
2733 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2734 // If we have deferred set_locals there might be oops waiting to be
2735 // written
2736 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2737 if (list != NULL) {
2738 for (int i = 0; i < list->length(); i++) {
2739 list->at(i)->oops_do(f);
2740 }
2741 }
2742
2743 // Traverse instance variables at the end since the GC may be moving things
2744 // around using this function
2745 f->do_oop((oop*) &_threadObj);
2746 f->do_oop((oop*) &_vm_result);
2747 f->do_oop((oop*) &_exception_oop);
2748 f->do_oop((oop*) &_pending_async_exception);
2749
2750 if (jvmti_thread_state() != NULL) {
2751 jvmti_thread_state()->oops_do(f);
2752 }
2753 }
2754
2755 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2756 Thread::nmethods_do(cf); // (super method is a no-op)
2757
2758 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2759 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2760
2761 if (has_last_Java_frame()) {
2762 // Traverse the execution stack
2763 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2764 fst.current()->nmethods_do(cf);
2765 }
2766 }
2767 }
2768
2769 void JavaThread::metadata_do(void f(Metadata*)) {
2770 Thread::metadata_do(f);
2771 if (has_last_Java_frame()) {
2772 // Traverse the execution stack to call f() on the methods in the stack
2773 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2774 fst.current()->metadata_do(f);
2775 }
2776 } else if (is_Compiler_thread()) {
2777 // need to walk ciMetadata in current compile tasks to keep alive.
2778 CompilerThread* ct = (CompilerThread*)this;
2779 if (ct->env() != NULL) {
2780 ct->env()->metadata_do(f);
2781 }
2782 }
2783 }
2784
2785 // Printing
2786 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2787 switch (_thread_state) {
2788 case _thread_uninitialized: return "_thread_uninitialized";
2789 case _thread_new: return "_thread_new";
2790 case _thread_new_trans: return "_thread_new_trans";
2791 case _thread_in_native: return "_thread_in_native";
2792 case _thread_in_native_trans: return "_thread_in_native_trans";
2793 case _thread_in_vm: return "_thread_in_vm";
2794 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2795 case _thread_in_Java: return "_thread_in_Java";
2796 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2797 case _thread_blocked: return "_thread_blocked";
2798 case _thread_blocked_trans: return "_thread_blocked_trans";
2799 default: return "unknown thread state";
2800 }
2801 }
2802
2803 #ifndef PRODUCT
2804 void JavaThread::print_thread_state_on(outputStream *st) const {
2805 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2806 };
2807 void JavaThread::print_thread_state() const {
2808 print_thread_state_on(tty);
2809 };
2810 #endif // PRODUCT
2811
2812 // Called by Threads::print() for VM_PrintThreads operation
2813 void JavaThread::print_on(outputStream *st) const {
2814 st->print("\"%s\" ", get_thread_name());
2815 oop thread_oop = threadObj();
2816 if (thread_oop != NULL) {
2817 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2818 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2819 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2820 }
2821 Thread::print_on(st);
2822 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2823 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2824 if (thread_oop != NULL) {
2825 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2826 }
2827 #ifndef PRODUCT
2828 print_thread_state_on(st);
2829 _safepoint_state->print_on(st);
2830 #endif // PRODUCT
2831 }
2832
2833 // Called by fatal error handler. The difference between this and
2834 // JavaThread::print() is that we can't grab lock or allocate memory.
2835 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2836 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2837 oop thread_obj = threadObj();
2838 if (thread_obj != NULL) {
2839 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2840 }
2841 st->print(" [");
2842 st->print("%s", _get_thread_state_name(_thread_state));
2843 if (osthread()) {
2844 st->print(", id=%d", osthread()->thread_id());
2845 }
2846 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2847 _stack_base - _stack_size, _stack_base);
2848 st->print("]");
2849 return;
2850 }
2851
2852 // Verification
2853
2854 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2855
2856 void JavaThread::verify() {
2857 // Verify oops in the thread.
2858 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2859
2860 // Verify the stack frames.
2861 frames_do(frame_verify);
2862 }
2863
2864 // CR 6300358 (sub-CR 2137150)
2865 // Most callers of this method assume that it can't return NULL but a
2866 // thread may not have a name whilst it is in the process of attaching to
2867 // the VM - see CR 6412693, and there are places where a JavaThread can be
2868 // seen prior to having it's threadObj set (eg JNI attaching threads and
2869 // if vm exit occurs during initialization). These cases can all be accounted
2870 // for such that this method never returns NULL.
2871 const char* JavaThread::get_thread_name() const {
2872 #ifdef ASSERT
2873 // early safepoints can hit while current thread does not yet have TLS
2874 if (!SafepointSynchronize::is_at_safepoint()) {
2875 Thread *cur = Thread::current();
2876 if (!(cur->is_Java_thread() && cur == this)) {
2877 // Current JavaThreads are allowed to get their own name without
2878 // the Threads_lock.
2879 assert_locked_or_safepoint(Threads_lock);
2880 }
2881 }
2882 #endif // ASSERT
2883 return get_thread_name_string();
2884 }
2885
2886 // Returns a non-NULL representation of this thread's name, or a suitable
2887 // descriptive string if there is no set name
2888 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2889 const char* name_str;
2890 oop thread_obj = threadObj();
2891 if (thread_obj != NULL) {
2892 typeArrayOop name = java_lang_Thread::name(thread_obj);
2893 if (name != NULL) {
2894 if (buf == NULL) {
2895 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2896 }
2897 else {
2898 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2899 }
2900 }
2901 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2902 name_str = "<no-name - thread is attaching>";
2903 }
2904 else {
2905 name_str = Thread::name();
2906 }
2907 }
2908 else {
2909 name_str = Thread::name();
2910 }
2911 assert(name_str != NULL, "unexpected NULL thread name");
2912 return name_str;
2913 }
2914
2915
2916 const char* JavaThread::get_threadgroup_name() const {
2917 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2918 oop thread_obj = threadObj();
2919 if (thread_obj != NULL) {
2920 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2921 if (thread_group != NULL) {
2922 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2923 // ThreadGroup.name can be null
2924 if (name != NULL) {
2925 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2926 return str;
2927 }
2928 }
2929 }
2930 return NULL;
2931 }
2932
2933 const char* JavaThread::get_parent_name() const {
2934 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2935 oop thread_obj = threadObj();
2936 if (thread_obj != NULL) {
2937 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2938 if (thread_group != NULL) {
2939 oop parent = java_lang_ThreadGroup::parent(thread_group);
2940 if (parent != NULL) {
2941 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2942 // ThreadGroup.name can be null
2943 if (name != NULL) {
2944 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2945 return str;
2946 }
2947 }
2948 }
2949 }
2950 return NULL;
2951 }
2952
2953 ThreadPriority JavaThread::java_priority() const {
2954 oop thr_oop = threadObj();
2955 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2956 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2957 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2958 return priority;
2959 }
2960
2961 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2962
2963 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2964 // Link Java Thread object <-> C++ Thread
2965
2966 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2967 // and put it into a new Handle. The Handle "thread_oop" can then
2968 // be used to pass the C++ thread object to other methods.
2969
2970 // Set the Java level thread object (jthread) field of the
2971 // new thread (a JavaThread *) to C++ thread object using the
2972 // "thread_oop" handle.
2973
2974 // Set the thread field (a JavaThread *) of the
2975 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2976
2977 Handle thread_oop(Thread::current(),
2978 JNIHandles::resolve_non_null(jni_thread));
2979 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2980 "must be initialized");
2981 set_threadObj(thread_oop());
2982 java_lang_Thread::set_thread(thread_oop(), this);
2983
2984 if (prio == NoPriority) {
2985 prio = java_lang_Thread::priority(thread_oop());
2986 assert(prio != NoPriority, "A valid priority should be present");
2987 }
2988
2989 // Push the Java priority down to the native thread; needs Threads_lock
2990 Thread::set_priority(this, prio);
2991
2992 // Add the new thread to the Threads list and set it in motion.
2993 // We must have threads lock in order to call Threads::add.
2994 // It is crucial that we do not block before the thread is
2995 // added to the Threads list for if a GC happens, then the java_thread oop
2996 // will not be visited by GC.
2997 Threads::add(this);
2998 }
2999
3000 oop JavaThread::current_park_blocker() {
3001 // Support for JSR-166 locks
3002 oop thread_oop = threadObj();
3003 if (thread_oop != NULL &&
3004 JDK_Version::current().supports_thread_park_blocker()) {
3005 return java_lang_Thread::park_blocker(thread_oop);
3006 }
3007 return NULL;
3008 }
3009
3010
3011 void JavaThread::print_stack_on(outputStream* st) {
3012 if (!has_last_Java_frame()) return;
3013 ResourceMark rm;
3014 HandleMark hm;
3015
3016 RegisterMap reg_map(this);
3017 vframe* start_vf = last_java_vframe(®_map);
3018 int count = 0;
3019 for (vframe* f = start_vf; f; f = f->sender()) {
3020 if (f->is_java_frame()) {
3021 javaVFrame* jvf = javaVFrame::cast(f);
3022 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3023
3024 // Print out lock information
3025 if (JavaMonitorsInStackTrace) {
3026 jvf->print_lock_info_on(st, count);
3027 }
3028 } else {
3029 // Ignore non-Java frames
3030 }
3031
3032 // Bail-out case for too deep stacks
3033 count++;
3034 if (MaxJavaStackTraceDepth == count) return;
3035 }
3036 }
3037
3038
3039 // JVMTI PopFrame support
3040 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3041 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3042 if (in_bytes(size_in_bytes) != 0) {
3043 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3044 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3045 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3046 }
3047 }
3048
3049 void* JavaThread::popframe_preserved_args() {
3050 return _popframe_preserved_args;
3051 }
3052
3053 ByteSize JavaThread::popframe_preserved_args_size() {
3054 return in_ByteSize(_popframe_preserved_args_size);
3055 }
3056
3057 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3058 int sz = in_bytes(popframe_preserved_args_size());
3059 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3060 return in_WordSize(sz / wordSize);
3061 }
3062
3063 void JavaThread::popframe_free_preserved_args() {
3064 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3065 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3066 _popframe_preserved_args = NULL;
3067 _popframe_preserved_args_size = 0;
3068 }
3069
3070 #ifndef PRODUCT
3071
3072 void JavaThread::trace_frames() {
3073 tty->print_cr("[Describe stack]");
3074 int frame_no = 1;
3075 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3076 tty->print(" %d. ", frame_no++);
3077 fst.current()->print_value_on(tty, this);
3078 tty->cr();
3079 }
3080 }
3081
3082 class PrintAndVerifyOopClosure: public OopClosure {
3083 protected:
3084 template <class T> inline void do_oop_work(T* p) {
3085 oop obj = oopDesc::load_decode_heap_oop(p);
3086 if (obj == NULL) return;
3087 tty->print(INTPTR_FORMAT ": ", p);
3088 if (obj->is_oop_or_null()) {
3089 if (obj->is_objArray()) {
3090 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3091 } else {
3092 obj->print();
3093 }
3094 } else {
3095 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3096 }
3097 tty->cr();
3098 }
3099 public:
3100 virtual void do_oop(oop* p) { do_oop_work(p); }
3101 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3102 };
3103
3104
3105 static void oops_print(frame* f, const RegisterMap *map) {
3106 PrintAndVerifyOopClosure print;
3107 f->print_value();
3108 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3109 }
3110
3111 // Print our all the locations that contain oops and whether they are
3112 // valid or not. This useful when trying to find the oldest frame
3113 // where an oop has gone bad since the frame walk is from youngest to
3114 // oldest.
3115 void JavaThread::trace_oops() {
3116 tty->print_cr("[Trace oops]");
3117 frames_do(oops_print);
3118 }
3119
3120
3121 #ifdef ASSERT
3122 // Print or validate the layout of stack frames
3123 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3124 ResourceMark rm;
3125 PRESERVE_EXCEPTION_MARK;
3126 FrameValues values;
3127 int frame_no = 0;
3128 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3129 fst.current()->describe(values, ++frame_no);
3130 if (depth == frame_no) break;
3131 }
3132 if (validate_only) {
3133 values.validate();
3134 } else {
3135 tty->print_cr("[Describe stack layout]");
3136 values.print(this);
3137 }
3138 }
3139 #endif
3140
3141 void JavaThread::trace_stack_from(vframe* start_vf) {
3142 ResourceMark rm;
3143 int vframe_no = 1;
3144 for (vframe* f = start_vf; f; f = f->sender()) {
3145 if (f->is_java_frame()) {
3146 javaVFrame::cast(f)->print_activation(vframe_no++);
3147 } else {
3148 f->print();
3149 }
3150 if (vframe_no > StackPrintLimit) {
3151 tty->print_cr("...<more frames>...");
3152 return;
3153 }
3154 }
3155 }
3156
3157
3158 void JavaThread::trace_stack() {
3159 if (!has_last_Java_frame()) return;
3160 ResourceMark rm;
3161 HandleMark hm;
3162 RegisterMap reg_map(this);
3163 trace_stack_from(last_java_vframe(®_map));
3164 }
3165
3166
3167 #endif // PRODUCT
3168
3169
3170 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3171 assert(reg_map != NULL, "a map must be given");
3172 frame f = last_frame();
3173 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3174 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3175 }
3176 return NULL;
3177 }
3178
3179
3180 Klass* JavaThread::security_get_caller_class(int depth) {
3181 vframeStream vfst(this);
3182 vfst.security_get_caller_frame(depth);
3183 if (!vfst.at_end()) {
3184 return vfst.method()->method_holder();
3185 }
3186 return NULL;
3187 }
3188
3189 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3190 assert(thread->is_Compiler_thread(), "must be compiler thread");
3191 CompileBroker::compiler_thread_loop();
3192 }
3193
3194 // Create a CompilerThread
3195 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3196 : JavaThread(&compiler_thread_entry) {
3197 _env = NULL;
3198 _log = NULL;
3199 _task = NULL;
3200 _queue = queue;
3201 _counters = counters;
3202 _buffer_blob = NULL;
3203 _scanned_nmethod = NULL;
3204 _compiler = NULL;
3205
3206 #ifndef PRODUCT
3207 _ideal_graph_printer = NULL;
3208 #endif
3209 }
3210
3211 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3212 JavaThread::oops_do(f, cld_f, cf);
3213 if (_scanned_nmethod != NULL && cf != NULL) {
3214 // Safepoints can occur when the sweeper is scanning an nmethod so
3215 // process it here to make sure it isn't unloaded in the middle of
3216 // a scan.
3217 cf->do_code_blob(_scanned_nmethod);
3218 }
3219 }
3220
3221
3222 // ======= Threads ========
3223
3224 // The Threads class links together all active threads, and provides
3225 // operations over all threads. It is protected by its own Mutex
3226 // lock, which is also used in other contexts to protect thread
3227 // operations from having the thread being operated on from exiting
3228 // and going away unexpectedly (e.g., safepoint synchronization)
3229
3230 JavaThread* Threads::_thread_list = NULL;
3231 int Threads::_number_of_threads = 0;
3232 int Threads::_number_of_non_daemon_threads = 0;
3233 int Threads::_return_code = 0;
3234 size_t JavaThread::_stack_size_at_create = 0;
3235 #ifdef ASSERT
3236 bool Threads::_vm_complete = false;
3237 #endif
3238
3239 // All JavaThreads
3240 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3241
3242 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3243 void Threads::threads_do(ThreadClosure* tc) {
3244 assert_locked_or_safepoint(Threads_lock);
3245 // ALL_JAVA_THREADS iterates through all JavaThreads
3246 ALL_JAVA_THREADS(p) {
3247 tc->do_thread(p);
3248 }
3249 // Someday we could have a table or list of all non-JavaThreads.
3250 // For now, just manually iterate through them.
3251 tc->do_thread(VMThread::vm_thread());
3252 Universe::heap()->gc_threads_do(tc);
3253 WatcherThread *wt = WatcherThread::watcher_thread();
3254 // Strictly speaking, the following NULL check isn't sufficient to make sure
3255 // the data for WatcherThread is still valid upon being examined. However,
3256 // considering that WatchThread terminates when the VM is on the way to
3257 // exit at safepoint, the chance of the above is extremely small. The right
3258 // way to prevent termination of WatcherThread would be to acquire
3259 // Terminator_lock, but we can't do that without violating the lock rank
3260 // checking in some cases.
3261 if (wt != NULL)
3262 tc->do_thread(wt);
3263
3264 // If CompilerThreads ever become non-JavaThreads, add them here
3265 }
3266
3267
3268 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3269 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3270
3271 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3272 create_vm_init_libraries();
3273 }
3274
3275 initialize_class(vmSymbols::java_lang_String(), CHECK);
3276
3277 // Initialize java_lang.System (needed before creating the thread)
3278 initialize_class(vmSymbols::java_lang_System(), CHECK);
3279 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3280 Handle thread_group = create_initial_thread_group(CHECK);
3281 Universe::set_main_thread_group(thread_group());
3282 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3283 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3284 main_thread->set_threadObj(thread_object);
3285 // Set thread status to running since main thread has
3286 // been started and running.
3287 java_lang_Thread::set_thread_status(thread_object,
3288 java_lang_Thread::RUNNABLE);
3289
3290 // The VM creates & returns objects of this class. Make sure it's initialized.
3291 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3292
3293 // The VM preresolves methods to these classes. Make sure that they get initialized
3294 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3295 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3296 call_initializeSystemClass(CHECK);
3297
3298 // get the Java runtime name after java.lang.System is initialized
3299 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3300 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3301
3302 // an instance of OutOfMemory exception has been allocated earlier
3303 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3304 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3305 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3306 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3307 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3308 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3309 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3310 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3311 }
3312
3313 void Threads::initialize_jsr292_core_classes(TRAPS) {
3314 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3315 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3316 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3317 }
3318
3319 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3320
3321 extern void JDK_Version_init();
3322
3323 // Check version
3324 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3325
3326 // Initialize the output stream module
3327 ostream_init();
3328
3329 // Process java launcher properties.
3330 Arguments::process_sun_java_launcher_properties(args);
3331
3332 // Initialize the os module before using TLS
3333 os::init();
3334
3335 // Initialize system properties.
3336 Arguments::init_system_properties();
3337
3338 // So that JDK version can be used as a discriminator when parsing arguments
3339 JDK_Version_init();
3340
3341 // Update/Initialize System properties after JDK version number is known
3342 Arguments::init_version_specific_system_properties();
3343
3344 // Parse arguments
3345 jint parse_result = Arguments::parse(args);
3346 if (parse_result != JNI_OK) return parse_result;
3347
3348 os::init_before_ergo();
3349
3350 jint ergo_result = Arguments::apply_ergo();
3351 if (ergo_result != JNI_OK) return ergo_result;
3352
3353 if (PauseAtStartup) {
3354 os::pause();
3355 }
3356
3357 HOTSPOT_VM_INIT_BEGIN();
3358
3359 // Record VM creation timing statistics
3360 TraceVmCreationTime create_vm_timer;
3361 create_vm_timer.start();
3362
3363 // Timing (must come after argument parsing)
3364 TraceTime timer("Create VM", TraceStartupTime);
3365
3366 // Initialize the os module after parsing the args
3367 jint os_init_2_result = os::init_2();
3368 if (os_init_2_result != JNI_OK) return os_init_2_result;
3369
3370 jint adjust_after_os_result = Arguments::adjust_after_os();
3371 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3372
3373 // initialize TLS
3374 ThreadLocalStorage::init();
3375
3376 // Bootstrap native memory tracking, so it can start recording memory
3377 // activities before worker thread is started. This is the first phase
3378 // of bootstrapping, VM is currently running in single-thread mode.
3379 MemTracker::bootstrap_single_thread();
3380
3381 // Initialize output stream logging
3382 ostream_init_log();
3383
3384 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3385 // Must be before create_vm_init_agents()
3386 if (Arguments::init_libraries_at_startup()) {
3387 convert_vm_init_libraries_to_agents();
3388 }
3389
3390 // Launch -agentlib/-agentpath and converted -Xrun agents
3391 if (Arguments::init_agents_at_startup()) {
3392 create_vm_init_agents();
3393 }
3394
3395 // Initialize Threads state
3396 _thread_list = NULL;
3397 _number_of_threads = 0;
3398 _number_of_non_daemon_threads = 0;
3399
3400 // Initialize global data structures and create system classes in heap
3401 vm_init_globals();
3402
3403 // Attach the main thread to this os thread
3404 JavaThread* main_thread = new JavaThread();
3405 main_thread->set_thread_state(_thread_in_vm);
3406 // must do this before set_active_handles and initialize_thread_local_storage
3407 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3408 // change the stack size recorded here to one based on the java thread
3409 // stacksize. This adjusted size is what is used to figure the placement
3410 // of the guard pages.
3411 main_thread->record_stack_base_and_size();
3412 main_thread->initialize_thread_local_storage();
3413
3414 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3415
3416 if (!main_thread->set_as_starting_thread()) {
3417 vm_shutdown_during_initialization(
3418 "Failed necessary internal allocation. Out of swap space");
3419 delete main_thread;
3420 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3421 return JNI_ENOMEM;
3422 }
3423
3424 // Enable guard page *after* os::create_main_thread(), otherwise it would
3425 // crash Linux VM, see notes in os_linux.cpp.
3426 main_thread->create_stack_guard_pages();
3427
3428 // Initialize Java-Level synchronization subsystem
3429 ObjectMonitor::Initialize();
3430
3431 // Second phase of bootstrapping, VM is about entering multi-thread mode
3432 MemTracker::bootstrap_multi_thread();
3433
3434 // Initialize global modules
3435 jint status = init_globals();
3436 if (status != JNI_OK) {
3437 delete main_thread;
3438 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3439 return status;
3440 }
3441
3442 // Should be done after the heap is fully created
3443 main_thread->cache_global_variables();
3444
3445 HandleMark hm;
3446
3447 { MutexLocker mu(Threads_lock);
3448 Threads::add(main_thread);
3449 }
3450
3451 // Any JVMTI raw monitors entered in onload will transition into
3452 // real raw monitor. VM is setup enough here for raw monitor enter.
3453 JvmtiExport::transition_pending_onload_raw_monitors();
3454
3455 // Fully start NMT
3456 MemTracker::start();
3457
3458 // Create the VMThread
3459 { TraceTime timer("Start VMThread", TraceStartupTime);
3460 VMThread::create();
3461 Thread* vmthread = VMThread::vm_thread();
3462
3463 if (!os::create_thread(vmthread, os::vm_thread))
3464 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3465
3466 // Wait for the VM thread to become ready, and VMThread::run to initialize
3467 // Monitors can have spurious returns, must always check another state flag
3468 {
3469 MutexLocker ml(Notify_lock);
3470 os::start_thread(vmthread);
3471 while (vmthread->active_handles() == NULL) {
3472 Notify_lock->wait();
3473 }
3474 }
3475 }
3476
3477 assert(Universe::is_fully_initialized(), "not initialized");
3478 if (VerifyDuringStartup) {
3479 // Make sure we're starting with a clean slate.
3480 VM_Verify verify_op;
3481 VMThread::execute(&verify_op);
3482 }
3483
3484 Thread* THREAD = Thread::current();
3485
3486 // At this point, the Universe is initialized, but we have not executed
3487 // any byte code. Now is a good time (the only time) to dump out the
3488 // internal state of the JVM for sharing.
3489 if (DumpSharedSpaces) {
3490 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3491 ShouldNotReachHere();
3492 }
3493
3494 // Always call even when there are not JVMTI environments yet, since environments
3495 // may be attached late and JVMTI must track phases of VM execution
3496 JvmtiExport::enter_start_phase();
3497
3498 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3499 JvmtiExport::post_vm_start();
3500
3501 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3502
3503 // We need this for ClassDataSharing - the initial vm.info property is set
3504 // with the default value of CDS "sharing" which may be reset through
3505 // command line options.
3506 reset_vm_info_property(CHECK_JNI_ERR);
3507
3508 quicken_jni_functions();
3509
3510 // Must be run after init_ft which initializes ft_enabled
3511 if (TRACE_INITIALIZE() != JNI_OK) {
3512 vm_exit_during_initialization("Failed to initialize tracing backend");
3513 }
3514
3515 // Set flag that basic initialization has completed. Used by exceptions and various
3516 // debug stuff, that does not work until all basic classes have been initialized.
3517 set_init_completed();
3518
3519 Metaspace::post_initialize();
3520
3521 HOTSPOT_VM_INIT_END();
3522
3523 // record VM initialization completion time
3524 #if INCLUDE_MANAGEMENT
3525 Management::record_vm_init_completed();
3526 #endif // INCLUDE_MANAGEMENT
3527
3528 // Compute system loader. Note that this has to occur after set_init_completed, since
3529 // valid exceptions may be thrown in the process.
3530 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3531 // set_init_completed has just been called, causing exceptions not to be shortcut
3532 // anymore. We call vm_exit_during_initialization directly instead.
3533 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3534
3535 #if INCLUDE_ALL_GCS
3536 // Support for ConcurrentMarkSweep. This should be cleaned up
3537 // and better encapsulated. The ugly nested if test would go away
3538 // once things are properly refactored. XXX YSR
3539 if (UseConcMarkSweepGC || UseG1GC) {
3540 if (UseConcMarkSweepGC) {
3541 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3542 } else {
3543 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3544 }
3545 }
3546 #endif // INCLUDE_ALL_GCS
3547
3548 // Always call even when there are not JVMTI environments yet, since environments
3549 // may be attached late and JVMTI must track phases of VM execution
3550 JvmtiExport::enter_live_phase();
3551
3552 // Signal Dispatcher needs to be started before VMInit event is posted
3553 os::signal_init();
3554
3555 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3556 if (!DisableAttachMechanism) {
3557 AttachListener::vm_start();
3558 if (StartAttachListener || AttachListener::init_at_startup()) {
3559 AttachListener::init();
3560 }
3561 }
3562
3563 // Launch -Xrun agents
3564 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3565 // back-end can launch with -Xdebug -Xrunjdwp.
3566 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3567 create_vm_init_libraries();
3568 }
3569
3570 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3571 JvmtiExport::post_vm_initialized();
3572
3573 if (TRACE_START() != JNI_OK) {
3574 vm_exit_during_initialization("Failed to start tracing backend.");
3575 }
3576
3577 if (CleanChunkPoolAsync) {
3578 Chunk::start_chunk_pool_cleaner_task();
3579 }
3580
3581 // initialize compiler(s)
3582 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3583 CompileBroker::compilation_init();
3584 #endif
3585
3586 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3587 // It is done after compilers are initialized, because otherwise compilations of
3588 // signature polymorphic MH intrinsics can be missed
3589 // (see SystemDictionary::find_method_handle_intrinsic).
3590 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3591
3592 #if INCLUDE_MANAGEMENT
3593 Management::initialize(THREAD);
3594
3595 if (HAS_PENDING_EXCEPTION) {
3596 // management agent fails to start possibly due to
3597 // configuration problem and is responsible for printing
3598 // stack trace if appropriate. Simply exit VM.
3599 vm_exit(1);
3600 }
3601 #endif // INCLUDE_MANAGEMENT
3602
3603 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3604 if (MemProfiling) MemProfiler::engage();
3605 StatSampler::engage();
3606 if (CheckJNICalls) JniPeriodicChecker::engage();
3607
3608 BiasedLocking::init();
3609
3610 #if INCLUDE_RTM_OPT
3611 RTMLockingCounters::init();
3612 #endif
3613
3614 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3615 call_postVMInitHook(THREAD);
3616 // The Java side of PostVMInitHook.run must deal with all
3617 // exceptions and provide means of diagnosis.
3618 if (HAS_PENDING_EXCEPTION) {
3619 CLEAR_PENDING_EXCEPTION;
3620 }
3621 }
3622
3623 {
3624 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3625 // Make sure the watcher thread can be started by WatcherThread::start()
3626 // or by dynamic enrollment.
3627 WatcherThread::make_startable();
3628 // Start up the WatcherThread if there are any periodic tasks
3629 // NOTE: All PeriodicTasks should be registered by now. If they
3630 // aren't, late joiners might appear to start slowly (we might
3631 // take a while to process their first tick).
3632 if (PeriodicTask::num_tasks() > 0) {
3633 WatcherThread::start();
3634 }
3635 }
3636
3637 // Give os specific code one last chance to start
3638 os::init_3();
3639
3640 create_vm_timer.end();
3641 #ifdef ASSERT
3642 _vm_complete = true;
3643 #endif
3644 return JNI_OK;
3645 }
3646
3647 // type for the Agent_OnLoad and JVM_OnLoad entry points
3648 extern "C" {
3649 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3650 }
3651 // Find a command line agent library and return its entry point for
3652 // -agentlib: -agentpath: -Xrun
3653 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3654 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3655 OnLoadEntry_t on_load_entry = NULL;
3656 void *library = NULL;
3657
3658 if (!agent->valid()) {
3659 char buffer[JVM_MAXPATHLEN];
3660 char ebuf[1024];
3661 const char *name = agent->name();
3662 const char *msg = "Could not find agent library ";
3663
3664 // First check to see if agent is statically linked into executable
3665 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3666 library = agent->os_lib();
3667 } else if (agent->is_absolute_path()) {
3668 library = os::dll_load(name, ebuf, sizeof ebuf);
3669 if (library == NULL) {
3670 const char *sub_msg = " in absolute path, with error: ";
3671 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3672 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3673 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3674 // If we can't find the agent, exit.
3675 vm_exit_during_initialization(buf, NULL);
3676 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3677 }
3678 } else {
3679 // Try to load the agent from the standard dll directory
3680 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3681 name)) {
3682 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3683 }
3684 if (library == NULL) { // Try the local directory
3685 char ns[1] = {0};
3686 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3687 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3688 }
3689 if (library == NULL) {
3690 const char *sub_msg = " on the library path, with error: ";
3691 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3692 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3693 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3694 // If we can't find the agent, exit.
3695 vm_exit_during_initialization(buf, NULL);
3696 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3697 }
3698 }
3699 }
3700 agent->set_os_lib(library);
3701 agent->set_valid();
3702 }
3703
3704 // Find the OnLoad function.
3705 on_load_entry =
3706 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3707 false,
3708 on_load_symbols,
3709 num_symbol_entries));
3710 return on_load_entry;
3711 }
3712
3713 // Find the JVM_OnLoad entry point
3714 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3715 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3716 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3717 }
3718
3719 // Find the Agent_OnLoad entry point
3720 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3721 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3722 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3723 }
3724
3725 // For backwards compatibility with -Xrun
3726 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3727 // treated like -agentpath:
3728 // Must be called before agent libraries are created
3729 void Threads::convert_vm_init_libraries_to_agents() {
3730 AgentLibrary* agent;
3731 AgentLibrary* next;
3732
3733 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3734 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3735 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3736
3737 // If there is an JVM_OnLoad function it will get called later,
3738 // otherwise see if there is an Agent_OnLoad
3739 if (on_load_entry == NULL) {
3740 on_load_entry = lookup_agent_on_load(agent);
3741 if (on_load_entry != NULL) {
3742 // switch it to the agent list -- so that Agent_OnLoad will be called,
3743 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3744 Arguments::convert_library_to_agent(agent);
3745 } else {
3746 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3747 }
3748 }
3749 }
3750 }
3751
3752 // Create agents for -agentlib: -agentpath: and converted -Xrun
3753 // Invokes Agent_OnLoad
3754 // Called very early -- before JavaThreads exist
3755 void Threads::create_vm_init_agents() {
3756 extern struct JavaVM_ main_vm;
3757 AgentLibrary* agent;
3758
3759 JvmtiExport::enter_onload_phase();
3760
3761 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3762 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3763
3764 if (on_load_entry != NULL) {
3765 // Invoke the Agent_OnLoad function
3766 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3767 if (err != JNI_OK) {
3768 vm_exit_during_initialization("agent library failed to init", agent->name());
3769 }
3770 } else {
3771 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3772 }
3773 }
3774 JvmtiExport::enter_primordial_phase();
3775 }
3776
3777 extern "C" {
3778 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3779 }
3780
3781 void Threads::shutdown_vm_agents() {
3782 // Send any Agent_OnUnload notifications
3783 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3784 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3785 extern struct JavaVM_ main_vm;
3786 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3787
3788 // Find the Agent_OnUnload function.
3789 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3790 os::find_agent_function(agent,
3791 false,
3792 on_unload_symbols,
3793 num_symbol_entries));
3794
3795 // Invoke the Agent_OnUnload function
3796 if (unload_entry != NULL) {
3797 JavaThread* thread = JavaThread::current();
3798 ThreadToNativeFromVM ttn(thread);
3799 HandleMark hm(thread);
3800 (*unload_entry)(&main_vm);
3801 }
3802 }
3803 }
3804
3805 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3806 // Invokes JVM_OnLoad
3807 void Threads::create_vm_init_libraries() {
3808 extern struct JavaVM_ main_vm;
3809 AgentLibrary* agent;
3810
3811 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3812 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3813
3814 if (on_load_entry != NULL) {
3815 // Invoke the JVM_OnLoad function
3816 JavaThread* thread = JavaThread::current();
3817 ThreadToNativeFromVM ttn(thread);
3818 HandleMark hm(thread);
3819 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3820 if (err != JNI_OK) {
3821 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3822 }
3823 } else {
3824 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3825 }
3826 }
3827 }
3828
3829 // Last thread running calls java.lang.Shutdown.shutdown()
3830 void JavaThread::invoke_shutdown_hooks() {
3831 HandleMark hm(this);
3832
3833 // We could get here with a pending exception, if so clear it now.
3834 if (this->has_pending_exception()) {
3835 this->clear_pending_exception();
3836 }
3837
3838 EXCEPTION_MARK;
3839 Klass* k =
3840 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3841 THREAD);
3842 if (k != NULL) {
3843 // SystemDictionary::resolve_or_null will return null if there was
3844 // an exception. If we cannot load the Shutdown class, just don't
3845 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3846 // and finalizers (if runFinalizersOnExit is set) won't be run.
3847 // Note that if a shutdown hook was registered or runFinalizersOnExit
3848 // was called, the Shutdown class would have already been loaded
3849 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3850 instanceKlassHandle shutdown_klass (THREAD, k);
3851 JavaValue result(T_VOID);
3852 JavaCalls::call_static(&result,
3853 shutdown_klass,
3854 vmSymbols::shutdown_method_name(),
3855 vmSymbols::void_method_signature(),
3856 THREAD);
3857 }
3858 CLEAR_PENDING_EXCEPTION;
3859 }
3860
3861 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3862 // the program falls off the end of main(). Another VM exit path is through
3863 // vm_exit() when the program calls System.exit() to return a value or when
3864 // there is a serious error in VM. The two shutdown paths are not exactly
3865 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3866 // and VM_Exit op at VM level.
3867 //
3868 // Shutdown sequence:
3869 // + Shutdown native memory tracking if it is on
3870 // + Wait until we are the last non-daemon thread to execute
3871 // <-- every thing is still working at this moment -->
3872 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3873 // shutdown hooks, run finalizers if finalization-on-exit
3874 // + Call before_exit(), prepare for VM exit
3875 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3876 // currently the only user of this mechanism is File.deleteOnExit())
3877 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3878 // post thread end and vm death events to JVMTI,
3879 // stop signal thread
3880 // + Call JavaThread::exit(), it will:
3881 // > release JNI handle blocks, remove stack guard pages
3882 // > remove this thread from Threads list
3883 // <-- no more Java code from this thread after this point -->
3884 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3885 // the compiler threads at safepoint
3886 // <-- do not use anything that could get blocked by Safepoint -->
3887 // + Disable tracing at JNI/JVM barriers
3888 // + Set _vm_exited flag for threads that are still running native code
3889 // + Delete this thread
3890 // + Call exit_globals()
3891 // > deletes tty
3892 // > deletes PerfMemory resources
3893 // + Return to caller
3894
3895 bool Threads::destroy_vm() {
3896 JavaThread* thread = JavaThread::current();
3897
3898 #ifdef ASSERT
3899 _vm_complete = false;
3900 #endif
3901 // Wait until we are the last non-daemon thread to execute
3902 { MutexLocker nu(Threads_lock);
3903 while (Threads::number_of_non_daemon_threads() > 1)
3904 // This wait should make safepoint checks, wait without a timeout,
3905 // and wait as a suspend-equivalent condition.
3906 //
3907 // Note: If the FlatProfiler is running and this thread is waiting
3908 // for another non-daemon thread to finish, then the FlatProfiler
3909 // is waiting for the external suspend request on this thread to
3910 // complete. wait_for_ext_suspend_completion() will eventually
3911 // timeout, but that takes time. Making this wait a suspend-
3912 // equivalent condition solves that timeout problem.
3913 //
3914 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3915 Mutex::_as_suspend_equivalent_flag);
3916 }
3917
3918 // Hang forever on exit if we are reporting an error.
3919 if (ShowMessageBoxOnError && is_error_reported()) {
3920 os::infinite_sleep();
3921 }
3922 os::wait_for_keypress_at_exit();
3923
3924 // run Java level shutdown hooks
3925 thread->invoke_shutdown_hooks();
3926
3927 before_exit(thread);
3928
3929 thread->exit(true);
3930
3931 // Stop VM thread.
3932 {
3933 // 4945125 The vm thread comes to a safepoint during exit.
3934 // GC vm_operations can get caught at the safepoint, and the
3935 // heap is unparseable if they are caught. Grab the Heap_lock
3936 // to prevent this. The GC vm_operations will not be able to
3937 // queue until after the vm thread is dead. After this point,
3938 // we'll never emerge out of the safepoint before the VM exits.
3939
3940 MutexLocker ml(Heap_lock);
3941
3942 VMThread::wait_for_vm_thread_exit();
3943 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3944 VMThread::destroy();
3945 }
3946
3947 // clean up ideal graph printers
3948 #if defined(COMPILER2) && !defined(PRODUCT)
3949 IdealGraphPrinter::clean_up();
3950 #endif
3951
3952 // Now, all Java threads are gone except daemon threads. Daemon threads
3953 // running Java code or in VM are stopped by the Safepoint. However,
3954 // daemon threads executing native code are still running. But they
3955 // will be stopped at native=>Java/VM barriers. Note that we can't
3956 // simply kill or suspend them, as it is inherently deadlock-prone.
3957
3958 #ifndef PRODUCT
3959 // disable function tracing at JNI/JVM barriers
3960 TraceJNICalls = false;
3961 TraceJVMCalls = false;
3962 TraceRuntimeCalls = false;
3963 #endif
3964
3965 VM_Exit::set_vm_exited();
3966
3967 notify_vm_shutdown();
3968
3969 delete thread;
3970
3971 // exit_globals() will delete tty
3972 exit_globals();
3973
3974 return true;
3975 }
3976
3977
3978 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3979 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3980 return is_supported_jni_version(version);
3981 }
3982
3983
3984 jboolean Threads::is_supported_jni_version(jint version) {
3985 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3986 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3987 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3988 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3989 return JNI_FALSE;
3990 }
3991
3992
3993 void Threads::add(JavaThread* p, bool force_daemon) {
3994 // The threads lock must be owned at this point
3995 assert_locked_or_safepoint(Threads_lock);
3996
3997 // See the comment for this method in thread.hpp for its purpose and
3998 // why it is called here.
3999 p->initialize_queues();
4000 p->set_next(_thread_list);
4001 _thread_list = p;
4002 _number_of_threads++;
4003 oop threadObj = p->threadObj();
4004 bool daemon = true;
4005 // Bootstrapping problem: threadObj can be null for initial
4006 // JavaThread (or for threads attached via JNI)
4007 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4008 _number_of_non_daemon_threads++;
4009 daemon = false;
4010 }
4011
4012 p->set_safepoint_visible(true);
4013
4014 ThreadService::add_thread(p, daemon);
4015
4016 // Possible GC point.
4017 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4018 }
4019
4020 void Threads::remove(JavaThread* p) {
4021 // Extra scope needed for Thread_lock, so we can check
4022 // that we do not remove thread without safepoint code notice
4023 { MutexLocker ml(Threads_lock);
4024
4025 assert(includes(p), "p must be present");
4026
4027 JavaThread* current = _thread_list;
4028 JavaThread* prev = NULL;
4029
4030 while (current != p) {
4031 prev = current;
4032 current = current->next();
4033 }
4034
4035 if (prev) {
4036 prev->set_next(current->next());
4037 } else {
4038 _thread_list = p->next();
4039 }
4040 _number_of_threads--;
4041 oop threadObj = p->threadObj();
4042 bool daemon = true;
4043 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4044 _number_of_non_daemon_threads--;
4045 daemon = false;
4046
4047 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4048 // on destroy_vm will wake up.
4049 if (number_of_non_daemon_threads() == 1)
4050 Threads_lock->notify_all();
4051 }
4052 ThreadService::remove_thread(p, daemon);
4053
4054 // Make sure that safepoint code disregard this thread. This is needed since
4055 // the thread might mess around with locks after this point. This can cause it
4056 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4057 // of this thread since it is removed from the queue.
4058 p->set_terminated_value();
4059
4060 // Now, this thread is not visible to safepoint
4061 p->set_safepoint_visible(false);
4062 // once the thread becomes safepoint invisible, we can not use its per-thread
4063 // recorder. And Threads::do_threads() no longer walks this thread, so we have
4064 // to release its per-thread recorder here.
4065 MemTracker::thread_exiting(p);
4066 } // unlock Threads_lock
4067
4068 // Since Events::log uses a lock, we grab it outside the Threads_lock
4069 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4070 }
4071
4072 // Threads_lock must be held when this is called (or must be called during a safepoint)
4073 bool Threads::includes(JavaThread* p) {
4074 assert(Threads_lock->is_locked(), "sanity check");
4075 ALL_JAVA_THREADS(q) {
4076 if (q == p) {
4077 return true;
4078 }
4079 }
4080 return false;
4081 }
4082
4083 // Operations on the Threads list for GC. These are not explicitly locked,
4084 // but the garbage collector must provide a safe context for them to run.
4085 // In particular, these things should never be called when the Threads_lock
4086 // is held by some other thread. (Note: the Safepoint abstraction also
4087 // uses the Threads_lock to guarantee this property. It also makes sure that
4088 // all threads gets blocked when exiting or starting).
4089
4090 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4091 ALL_JAVA_THREADS(p) {
4092 p->oops_do(f, cld_f, cf);
4093 }
4094 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4095 }
4096
4097 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4098 // Introduce a mechanism allowing parallel threads to claim threads as
4099 // root groups. Overhead should be small enough to use all the time,
4100 // even in sequential code.
4101 SharedHeap* sh = SharedHeap::heap();
4102 // Cannot yet substitute active_workers for n_par_threads
4103 // because of G1CollectedHeap::verify() use of
4104 // SharedHeap::process_strong_roots(). n_par_threads == 0 will
4105 // turn off parallelism in process_strong_roots while active_workers
4106 // is being used for parallelism elsewhere.
4107 bool is_par = sh->n_par_threads() > 0;
4108 assert(!is_par ||
4109 (SharedHeap::heap()->n_par_threads() ==
4110 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4111 int cp = SharedHeap::heap()->strong_roots_parity();
4112 ALL_JAVA_THREADS(p) {
4113 if (p->claim_oops_do(is_par, cp)) {
4114 p->oops_do(f, cld_f, cf);
4115 }
4116 }
4117 VMThread* vmt = VMThread::vm_thread();
4118 if (vmt->claim_oops_do(is_par, cp)) {
4119 vmt->oops_do(f, cld_f, cf);
4120 }
4121 }
4122
4123 #if INCLUDE_ALL_GCS
4124 // Used by ParallelScavenge
4125 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4126 ALL_JAVA_THREADS(p) {
4127 q->enqueue(new ThreadRootsTask(p));
4128 }
4129 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4130 }
4131
4132 // Used by Parallel Old
4133 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4134 ALL_JAVA_THREADS(p) {
4135 q->enqueue(new ThreadRootsMarkingTask(p));
4136 }
4137 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4138 }
4139 #endif // INCLUDE_ALL_GCS
4140
4141 void Threads::nmethods_do(CodeBlobClosure* cf) {
4142 ALL_JAVA_THREADS(p) {
4143 p->nmethods_do(cf);
4144 }
4145 VMThread::vm_thread()->nmethods_do(cf);
4146 }
4147
4148 void Threads::metadata_do(void f(Metadata*)) {
4149 ALL_JAVA_THREADS(p) {
4150 p->metadata_do(f);
4151 }
4152 }
4153
4154 void Threads::gc_epilogue() {
4155 ALL_JAVA_THREADS(p) {
4156 p->gc_epilogue();
4157 }
4158 }
4159
4160 void Threads::gc_prologue() {
4161 ALL_JAVA_THREADS(p) {
4162 p->gc_prologue();
4163 }
4164 }
4165
4166 void Threads::deoptimized_wrt_marked_nmethods() {
4167 ALL_JAVA_THREADS(p) {
4168 p->deoptimized_wrt_marked_nmethods();
4169 }
4170 }
4171
4172
4173 // Get count Java threads that are waiting to enter the specified monitor.
4174 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4175 address monitor, bool doLock) {
4176 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4177 "must grab Threads_lock or be at safepoint");
4178 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4179
4180 int i = 0;
4181 {
4182 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4183 ALL_JAVA_THREADS(p) {
4184 if (p->is_Compiler_thread()) continue;
4185
4186 address pending = (address)p->current_pending_monitor();
4187 if (pending == monitor) { // found a match
4188 if (i < count) result->append(p); // save the first count matches
4189 i++;
4190 }
4191 }
4192 }
4193 return result;
4194 }
4195
4196
4197 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4198 assert(doLock ||
4199 Threads_lock->owned_by_self() ||
4200 SafepointSynchronize::is_at_safepoint(),
4201 "must grab Threads_lock or be at safepoint");
4202
4203 // NULL owner means not locked so we can skip the search
4204 if (owner == NULL) return NULL;
4205
4206 {
4207 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4208 ALL_JAVA_THREADS(p) {
4209 // first, see if owner is the address of a Java thread
4210 if (owner == (address)p) return p;
4211 }
4212 }
4213 // Cannot assert on lack of success here since this function may be
4214 // used by code that is trying to report useful problem information
4215 // like deadlock detection.
4216 if (UseHeavyMonitors) return NULL;
4217
4218 //
4219 // If we didn't find a matching Java thread and we didn't force use of
4220 // heavyweight monitors, then the owner is the stack address of the
4221 // Lock Word in the owning Java thread's stack.
4222 //
4223 JavaThread* the_owner = NULL;
4224 {
4225 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4226 ALL_JAVA_THREADS(q) {
4227 if (q->is_lock_owned(owner)) {
4228 the_owner = q;
4229 break;
4230 }
4231 }
4232 }
4233 // cannot assert on lack of success here; see above comment
4234 return the_owner;
4235 }
4236
4237 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4238 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4239 char buf[32];
4240 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4241
4242 st->print_cr("Full thread dump %s (%s %s):",
4243 Abstract_VM_Version::vm_name(),
4244 Abstract_VM_Version::vm_release(),
4245 Abstract_VM_Version::vm_info_string()
4246 );
4247 st->cr();
4248
4249 #if INCLUDE_ALL_GCS
4250 // Dump concurrent locks
4251 ConcurrentLocksDump concurrent_locks;
4252 if (print_concurrent_locks) {
4253 concurrent_locks.dump_at_safepoint();
4254 }
4255 #endif // INCLUDE_ALL_GCS
4256
4257 ALL_JAVA_THREADS(p) {
4258 ResourceMark rm;
4259 p->print_on(st);
4260 if (print_stacks) {
4261 if (internal_format) {
4262 p->trace_stack();
4263 } else {
4264 p->print_stack_on(st);
4265 }
4266 }
4267 st->cr();
4268 #if INCLUDE_ALL_GCS
4269 if (print_concurrent_locks) {
4270 concurrent_locks.print_locks_on(p, st);
4271 }
4272 #endif // INCLUDE_ALL_GCS
4273 }
4274
4275 VMThread::vm_thread()->print_on(st);
4276 st->cr();
4277 Universe::heap()->print_gc_threads_on(st);
4278 WatcherThread* wt = WatcherThread::watcher_thread();
4279 if (wt != NULL) {
4280 wt->print_on(st);
4281 st->cr();
4282 }
4283 CompileBroker::print_compiler_threads_on(st);
4284 st->flush();
4285 }
4286
4287 // Threads::print_on_error() is called by fatal error handler. It's possible
4288 // that VM is not at safepoint and/or current thread is inside signal handler.
4289 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4290 // memory (even in resource area), it might deadlock the error handler.
4291 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4292 bool found_current = false;
4293 st->print_cr("Java Threads: ( => current thread )");
4294 ALL_JAVA_THREADS(thread) {
4295 bool is_current = (current == thread);
4296 found_current = found_current || is_current;
4297
4298 st->print("%s", is_current ? "=>" : " ");
4299
4300 st->print(PTR_FORMAT, thread);
4301 st->print(" ");
4302 thread->print_on_error(st, buf, buflen);
4303 st->cr();
4304 }
4305 st->cr();
4306
4307 st->print_cr("Other Threads:");
4308 if (VMThread::vm_thread()) {
4309 bool is_current = (current == VMThread::vm_thread());
4310 found_current = found_current || is_current;
4311 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4312
4313 st->print(PTR_FORMAT, VMThread::vm_thread());
4314 st->print(" ");
4315 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4316 st->cr();
4317 }
4318 WatcherThread* wt = WatcherThread::watcher_thread();
4319 if (wt != NULL) {
4320 bool is_current = (current == wt);
4321 found_current = found_current || is_current;
4322 st->print("%s", is_current ? "=>" : " ");
4323
4324 st->print(PTR_FORMAT, wt);
4325 st->print(" ");
4326 wt->print_on_error(st, buf, buflen);
4327 st->cr();
4328 }
4329 if (!found_current) {
4330 st->cr();
4331 st->print("=>" PTR_FORMAT " (exited) ", current);
4332 current->print_on_error(st, buf, buflen);
4333 st->cr();
4334 }
4335 }
4336
4337 // Internal SpinLock and Mutex
4338 // Based on ParkEvent
4339
4340 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4341 //
4342 // We employ SpinLocks _only for low-contention, fixed-length
4343 // short-duration critical sections where we're concerned
4344 // about native mutex_t or HotSpot Mutex:: latency.
4345 // The mux construct provides a spin-then-block mutual exclusion
4346 // mechanism.
4347 //
4348 // Testing has shown that contention on the ListLock guarding gFreeList
4349 // is common. If we implement ListLock as a simple SpinLock it's common
4350 // for the JVM to devolve to yielding with little progress. This is true
4351 // despite the fact that the critical sections protected by ListLock are
4352 // extremely short.
4353 //
4354 // TODO-FIXME: ListLock should be of type SpinLock.
4355 // We should make this a 1st-class type, integrated into the lock
4356 // hierarchy as leaf-locks. Critically, the SpinLock structure
4357 // should have sufficient padding to avoid false-sharing and excessive
4358 // cache-coherency traffic.
4359
4360
4361 typedef volatile int SpinLockT;
4362
4363 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4364 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4365 return; // normal fast-path return
4366 }
4367
4368 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4369 TEVENT(SpinAcquire - ctx);
4370 int ctr = 0;
4371 int Yields = 0;
4372 for (;;) {
4373 while (*adr != 0) {
4374 ++ctr;
4375 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4376 if (Yields > 5) {
4377 os::naked_short_sleep(1);
4378 } else {
4379 os::NakedYield();
4380 ++Yields;
4381 }
4382 } else {
4383 SpinPause();
4384 }
4385 }
4386 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4387 }
4388 }
4389
4390 void Thread::SpinRelease (volatile int * adr) {
4391 assert(*adr != 0, "invariant");
4392 OrderAccess::fence(); // guarantee at least release consistency.
4393 // Roach-motel semantics.
4394 // It's safe if subsequent LDs and STs float "up" into the critical section,
4395 // but prior LDs and STs within the critical section can't be allowed
4396 // to reorder or float past the ST that releases the lock.
4397 *adr = 0;
4398 }
4399
4400 // muxAcquire and muxRelease:
4401 //
4402 // * muxAcquire and muxRelease support a single-word lock-word construct.
4403 // The LSB of the word is set IFF the lock is held.
4404 // The remainder of the word points to the head of a singly-linked list
4405 // of threads blocked on the lock.
4406 //
4407 // * The current implementation of muxAcquire-muxRelease uses its own
4408 // dedicated Thread._MuxEvent instance. If we're interested in
4409 // minimizing the peak number of extant ParkEvent instances then
4410 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4411 // as certain invariants were satisfied. Specifically, care would need
4412 // to be taken with regards to consuming unpark() "permits".
4413 // A safe rule of thumb is that a thread would never call muxAcquire()
4414 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4415 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4416 // consume an unpark() permit intended for monitorenter, for instance.
4417 // One way around this would be to widen the restricted-range semaphore
4418 // implemented in park(). Another alternative would be to provide
4419 // multiple instances of the PlatformEvent() for each thread. One
4420 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4421 //
4422 // * Usage:
4423 // -- Only as leaf locks
4424 // -- for short-term locking only as muxAcquire does not perform
4425 // thread state transitions.
4426 //
4427 // Alternatives:
4428 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4429 // but with parking or spin-then-park instead of pure spinning.
4430 // * Use Taura-Oyama-Yonenzawa locks.
4431 // * It's possible to construct a 1-0 lock if we encode the lockword as
4432 // (List,LockByte). Acquire will CAS the full lockword while Release
4433 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4434 // acquiring threads use timers (ParkTimed) to detect and recover from
4435 // the stranding window. Thread/Node structures must be aligned on 256-byte
4436 // boundaries by using placement-new.
4437 // * Augment MCS with advisory back-link fields maintained with CAS().
4438 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4439 // The validity of the backlinks must be ratified before we trust the value.
4440 // If the backlinks are invalid the exiting thread must back-track through the
4441 // the forward links, which are always trustworthy.
4442 // * Add a successor indication. The LockWord is currently encoded as
4443 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4444 // to provide the usual futile-wakeup optimization.
4445 // See RTStt for details.
4446 // * Consider schedctl.sc_nopreempt to cover the critical section.
4447 //
4448
4449
4450 typedef volatile intptr_t MutexT; // Mux Lock-word
4451 enum MuxBits { LOCKBIT = 1 };
4452
4453 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4454 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4455 if (w == 0) return;
4456 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4457 return;
4458 }
4459
4460 TEVENT(muxAcquire - Contention);
4461 ParkEvent * const Self = Thread::current()->_MuxEvent;
4462 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4463 for (;;) {
4464 int its = (os::is_MP() ? 100 : 0) + 1;
4465
4466 // Optional spin phase: spin-then-park strategy
4467 while (--its >= 0) {
4468 w = *Lock;
4469 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4470 return;
4471 }
4472 }
4473
4474 Self->reset();
4475 Self->OnList = intptr_t(Lock);
4476 // The following fence() isn't _strictly necessary as the subsequent
4477 // CAS() both serializes execution and ratifies the fetched *Lock value.
4478 OrderAccess::fence();
4479 for (;;) {
4480 w = *Lock;
4481 if ((w & LOCKBIT) == 0) {
4482 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4483 Self->OnList = 0; // hygiene - allows stronger asserts
4484 return;
4485 }
4486 continue; // Interference -- *Lock changed -- Just retry
4487 }
4488 assert(w & LOCKBIT, "invariant");
4489 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4490 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4491 }
4492
4493 while (Self->OnList != 0) {
4494 Self->park();
4495 }
4496 }
4497 }
4498
4499 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4500 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4501 if (w == 0) return;
4502 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4503 return;
4504 }
4505
4506 TEVENT(muxAcquire - Contention);
4507 ParkEvent * ReleaseAfter = NULL;
4508 if (ev == NULL) {
4509 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4510 }
4511 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4512 for (;;) {
4513 guarantee(ev->OnList == 0, "invariant");
4514 int its = (os::is_MP() ? 100 : 0) + 1;
4515
4516 // Optional spin phase: spin-then-park strategy
4517 while (--its >= 0) {
4518 w = *Lock;
4519 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4520 if (ReleaseAfter != NULL) {
4521 ParkEvent::Release(ReleaseAfter);
4522 }
4523 return;
4524 }
4525 }
4526
4527 ev->reset();
4528 ev->OnList = intptr_t(Lock);
4529 // The following fence() isn't _strictly necessary as the subsequent
4530 // CAS() both serializes execution and ratifies the fetched *Lock value.
4531 OrderAccess::fence();
4532 for (;;) {
4533 w = *Lock;
4534 if ((w & LOCKBIT) == 0) {
4535 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4536 ev->OnList = 0;
4537 // We call ::Release while holding the outer lock, thus
4538 // artificially lengthening the critical section.
4539 // Consider deferring the ::Release() until the subsequent unlock(),
4540 // after we've dropped the outer lock.
4541 if (ReleaseAfter != NULL) {
4542 ParkEvent::Release(ReleaseAfter);
4543 }
4544 return;
4545 }
4546 continue; // Interference -- *Lock changed -- Just retry
4547 }
4548 assert(w & LOCKBIT, "invariant");
4549 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4550 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4551 }
4552
4553 while (ev->OnList != 0) {
4554 ev->park();
4555 }
4556 }
4557 }
4558
4559 // Release() must extract a successor from the list and then wake that thread.
4560 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4561 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4562 // Release() would :
4563 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4564 // (B) Extract a successor from the private list "in-hand"
4565 // (C) attempt to CAS() the residual back into *Lock over null.
4566 // If there were any newly arrived threads and the CAS() would fail.
4567 // In that case Release() would detach the RATs, re-merge the list in-hand
4568 // with the RATs and repeat as needed. Alternately, Release() might
4569 // detach and extract a successor, but then pass the residual list to the wakee.
4570 // The wakee would be responsible for reattaching and remerging before it
4571 // competed for the lock.
4572 //
4573 // Both "pop" and DMR are immune from ABA corruption -- there can be
4574 // multiple concurrent pushers, but only one popper or detacher.
4575 // This implementation pops from the head of the list. This is unfair,
4576 // but tends to provide excellent throughput as hot threads remain hot.
4577 // (We wake recently run threads first).
4578
4579 void Thread::muxRelease (volatile intptr_t * Lock) {
4580 for (;;) {
4581 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4582 assert(w & LOCKBIT, "invariant");
4583 if (w == LOCKBIT) return;
4584 ParkEvent * List = (ParkEvent *)(w & ~LOCKBIT);
4585 assert(List != NULL, "invariant");
4586 assert(List->OnList == intptr_t(Lock), "invariant");
4587 ParkEvent * nxt = List->ListNext;
4588
4589 // The following CAS() releases the lock and pops the head element.
4590 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4591 continue;
4592 }
4593 List->OnList = 0;
4594 OrderAccess::fence();
4595 List->unpark();
4596 return;
4597 }
4598 }
4599
4600
4601 void Threads::verify() {
4602 ALL_JAVA_THREADS(p) {
4603 p->verify();
4604 }
4605 VMThread* thread = VMThread::vm_thread();
4606 if (thread != NULL) thread->verify();
4607 }