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 #if INCLUDE_ALL_GCS
89 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
90 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
91 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
92 #endif // INCLUDE_ALL_GCS
93 #ifdef COMPILER1
94 #include "c1/c1_Compiler.hpp"
95 #endif
96 #ifdef COMPILER2
97 #include "opto/c2compiler.hpp"
98 #include "opto/idealGraphPrinter.hpp"
99 #endif
100 #if INCLUDE_RTM_OPT
101 #include "runtime/rtmLocking.hpp"
102 #endif
103
104 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
105
106 #ifdef DTRACE_ENABLED
107
108 // Only bother with this argument setup if dtrace is available
109
110 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
111 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
112
113 #define DTRACE_THREAD_PROBE(probe, javathread) \
114 { \
115 ResourceMark rm(this); \
116 int len = 0; \
117 const char* name = (javathread)->get_thread_name(); \
118 len = strlen(name); \
119 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
120 (char *) name, len, \
121 java_lang_Thread::thread_id((javathread)->threadObj()), \
122 (uintptr_t) (javathread)->osthread()->thread_id(), \
123 java_lang_Thread::is_daemon((javathread)->threadObj())); \
124 }
125
126 #else // ndef DTRACE_ENABLED
127
128 #define DTRACE_THREAD_PROBE(probe, javathread)
129
130 #endif // ndef DTRACE_ENABLED
131
132
133 // Class hierarchy
134 // - Thread
135 // - VMThread
136 // - WatcherThread
137 // - ConcurrentMarkSweepThread
138 // - JavaThread
139 // - CompilerThread
140
141 // ======= Thread ========
142 // Support for forcing alignment of thread objects for biased locking
143 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
144 if (UseBiasedLocking) {
145 const int alignment = markOopDesc::biased_lock_alignment;
146 size_t aligned_size = size + (alignment - sizeof(intptr_t));
147 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
148 : AllocateHeap(aligned_size, flags, CURRENT_PC,
149 AllocFailStrategy::RETURN_NULL);
150 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
151 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
152 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
153 "JavaThread alignment code overflowed allocated storage");
154 if (TraceBiasedLocking) {
155 if (aligned_addr != real_malloc_addr)
156 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
157 real_malloc_addr, aligned_addr);
158 }
159 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
160 return aligned_addr;
161 } else {
162 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
163 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
164 }
165 }
166
167 void Thread::operator delete(void* p) {
168 if (UseBiasedLocking) {
169 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
170 FreeHeap(real_malloc_addr, mtThread);
171 } else {
172 FreeHeap(p, mtThread);
173 }
174 }
175
176
177 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
178 // JavaThread
179
180
181 Thread::Thread() {
182 // stack and get_thread
183 set_stack_base(NULL);
184 set_stack_size(0);
185 set_self_raw_id(0);
186 set_lgrp_id(-1);
187
188 // allocated data structures
189 set_osthread(NULL);
190 set_resource_area(new (mtThread)ResourceArea());
191 DEBUG_ONLY(_current_resource_mark = NULL;)
192 set_handle_area(new (mtThread) HandleArea(NULL));
193 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
194 set_active_handles(NULL);
195 set_free_handle_block(NULL);
196 set_last_handle_mark(NULL);
197
198 // This initial value ==> never claimed.
199 _oops_do_parity = 0;
200
201 // the handle mark links itself to last_handle_mark
202 new HandleMark(this);
203
204 // plain initialization
205 debug_only(_owned_locks = NULL;)
206 debug_only(_allow_allocation_count = 0;)
207 NOT_PRODUCT(_allow_safepoint_count = 0;)
208 NOT_PRODUCT(_skip_gcalot = false;)
209 _jvmti_env_iteration_count = 0;
210 set_allocated_bytes(0);
211 _vm_operation_started_count = 0;
212 _vm_operation_completed_count = 0;
213 _current_pending_monitor = NULL;
214 _current_pending_monitor_is_from_java = true;
215 _current_waiting_monitor = NULL;
216 _num_nested_signal = 0;
217 omFreeList = NULL;
218 omFreeCount = 0;
219 omFreeProvision = 32;
220 omInUseList = NULL;
221 omInUseCount = 0;
222
223 #ifdef ASSERT
224 _visited_for_critical_count = false;
225 #endif
226
227 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
228 _suspend_flags = 0;
229
230 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
231 _hashStateX = os::random();
232 _hashStateY = 842502087;
233 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
234 _hashStateW = 273326509;
235
236 _OnTrap = 0;
237 _schedctl = NULL;
238 _Stalled = 0;
239 _TypeTag = 0x2BAD;
240
241 // Many of the following fields are effectively final - immutable
242 // Note that nascent threads can't use the Native Monitor-Mutex
243 // construct until the _MutexEvent is initialized ...
244 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
245 // we might instead use a stack of ParkEvents that we could provision on-demand.
246 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
247 // and ::Release()
248 _ParkEvent = ParkEvent::Allocate(this);
249 _SleepEvent = ParkEvent::Allocate(this);
250 _MutexEvent = ParkEvent::Allocate(this);
251 _MuxEvent = ParkEvent::Allocate(this);
252
253 #ifdef CHECK_UNHANDLED_OOPS
254 if (CheckUnhandledOops) {
255 _unhandled_oops = new UnhandledOops(this);
256 }
257 #endif // CHECK_UNHANDLED_OOPS
258 #ifdef ASSERT
259 if (UseBiasedLocking) {
260 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
261 assert(this == _real_malloc_address ||
262 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
263 "bug in forced alignment of thread objects");
264 }
265 #endif /* ASSERT */
266 }
267
268 void Thread::initialize_thread_local_storage() {
269 // Note: Make sure this method only calls
270 // non-blocking operations. Otherwise, it might not work
271 // with the thread-startup/safepoint interaction.
272
273 // During Java thread startup, safepoint code should allow this
274 // method to complete because it may need to allocate memory to
275 // store information for the new thread.
276
277 // initialize structure dependent on thread local storage
278 ThreadLocalStorage::set_thread(this);
279 }
280
281 void Thread::record_stack_base_and_size() {
282 set_stack_base(os::current_stack_base());
283 set_stack_size(os::current_stack_size());
284 if (is_Java_thread()) {
285 ((JavaThread*) this)->set_stack_overflow_limit();
286 }
287 // CR 7190089: on Solaris, primordial thread's stack is adjusted
288 // in initialize_thread(). Without the adjustment, stack size is
289 // incorrect if stack is set to unlimited (ulimit -s unlimited).
290 // So far, only Solaris has real implementation of initialize_thread().
291 //
292 // set up any platform-specific state.
293 os::initialize_thread(this);
294
295 #if INCLUDE_NMT
296 // record thread's native stack, stack grows downward
297 address stack_low_addr = stack_base() - stack_size();
298 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this,
299 CURRENT_PC);
300 #endif // INCLUDE_NMT
301 }
302
303
304 Thread::~Thread() {
305 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
306 ObjectSynchronizer::omFlush(this);
307
308 EVENT_THREAD_DESTRUCT(this);
309
310 // stack_base can be NULL if the thread is never started or exited before
311 // record_stack_base_and_size called. Although, we would like to ensure
312 // that all started threads do call record_stack_base_and_size(), there is
313 // not proper way to enforce that.
314 #if INCLUDE_NMT
315 if (_stack_base != NULL) {
316 address low_stack_addr = stack_base() - stack_size();
317 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this);
318 #ifdef ASSERT
319 set_stack_base(NULL);
320 #endif
321 }
322 #endif // INCLUDE_NMT
323
324 // deallocate data structures
325 delete resource_area();
326 // since the handle marks are using the handle area, we have to deallocated the root
327 // handle mark before deallocating the thread's handle area,
328 assert(last_handle_mark() != NULL, "check we have an element");
329 delete last_handle_mark();
330 assert(last_handle_mark() == NULL, "check we have reached the end");
331
332 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
333 // We NULL out the fields for good hygiene.
334 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
335 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
336 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
337 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
338
339 delete handle_area();
340 delete metadata_handles();
341
342 // osthread() can be NULL, if creation of thread failed.
343 if (osthread() != NULL) os::free_thread(osthread());
344
345 delete _SR_lock;
346
347 // clear thread local storage if the Thread is deleting itself
348 if (this == Thread::current()) {
349 ThreadLocalStorage::set_thread(NULL);
350 } else {
351 // In the case where we're not the current thread, invalidate all the
352 // caches in case some code tries to get the current thread or the
353 // thread that was destroyed, and gets stale information.
354 ThreadLocalStorage::invalidate_all();
355 }
356 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
357 }
358
359 // NOTE: dummy function for assertion purpose.
360 void Thread::run() {
361 ShouldNotReachHere();
362 }
363
364 #ifdef ASSERT
365 // Private method to check for dangling thread pointer
366 void check_for_dangling_thread_pointer(Thread *thread) {
367 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
368 "possibility of dangling Thread pointer");
369 }
370 #endif
371
372
373 #ifndef PRODUCT
374 // Tracing method for basic thread operations
375 void Thread::trace(const char* msg, const Thread* const thread) {
376 if (!TraceThreadEvents) return;
377 ResourceMark rm;
378 ThreadCritical tc;
379 const char *name = "non-Java thread";
380 int prio = -1;
381 if (thread->is_Java_thread()
382 && !thread->is_Compiler_thread()) {
383 // The Threads_lock must be held to get information about
384 // this thread but may not be in some situations when
385 // tracing thread events.
386 bool release_Threads_lock = false;
387 if (!Threads_lock->owned_by_self()) {
388 Threads_lock->lock();
389 release_Threads_lock = true;
390 }
391 JavaThread* jt = (JavaThread *)thread;
392 name = (char *)jt->get_thread_name();
393 oop thread_oop = jt->threadObj();
394 if (thread_oop != NULL) {
395 prio = java_lang_Thread::priority(thread_oop);
396 }
397 if (release_Threads_lock) {
398 Threads_lock->unlock();
399 }
400 }
401 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
402 }
403 #endif
404
405
406 ThreadPriority Thread::get_priority(const Thread* const thread) {
407 trace("get priority", thread);
408 ThreadPriority priority;
409 // Can return an error!
410 (void)os::get_priority(thread, priority);
411 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
412 return priority;
413 }
414
415 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
416 trace("set priority", thread);
417 debug_only(check_for_dangling_thread_pointer(thread);)
418 // Can return an error!
419 (void)os::set_priority(thread, priority);
420 }
421
422
423 void Thread::start(Thread* thread) {
424 trace("start", thread);
425 // Start is different from resume in that its safety is guaranteed by context or
426 // being called from a Java method synchronized on the Thread object.
427 if (!DisableStartThread) {
428 if (thread->is_Java_thread()) {
429 // Initialize the thread state to RUNNABLE before starting this thread.
430 // Can not set it after the thread started because we do not know the
431 // exact thread state at that time. It could be in MONITOR_WAIT or
432 // in SLEEPING or some other state.
433 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
434 java_lang_Thread::RUNNABLE);
435 }
436 os::start_thread(thread);
437 }
438 }
439
440 // Enqueue a VM_Operation to do the job for us - sometime later
441 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
442 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
443 VMThread::execute(vm_stop);
444 }
445
446
447 //
448 // Check if an external suspend request has completed (or has been
449 // cancelled). Returns true if the thread is externally suspended and
450 // false otherwise.
451 //
452 // The bits parameter returns information about the code path through
453 // the routine. Useful for debugging:
454 //
455 // set in is_ext_suspend_completed():
456 // 0x00000001 - routine was entered
457 // 0x00000010 - routine return false at end
458 // 0x00000100 - thread exited (return false)
459 // 0x00000200 - suspend request cancelled (return false)
460 // 0x00000400 - thread suspended (return true)
461 // 0x00001000 - thread is in a suspend equivalent state (return true)
462 // 0x00002000 - thread is native and walkable (return true)
463 // 0x00004000 - thread is native_trans and walkable (needed retry)
464 //
465 // set in wait_for_ext_suspend_completion():
466 // 0x00010000 - routine was entered
467 // 0x00020000 - suspend request cancelled before loop (return false)
468 // 0x00040000 - thread suspended before loop (return true)
469 // 0x00080000 - suspend request cancelled in loop (return false)
470 // 0x00100000 - thread suspended in loop (return true)
471 // 0x00200000 - suspend not completed during retry loop (return false)
472 //
473
474 // Helper class for tracing suspend wait debug bits.
475 //
476 // 0x00000100 indicates that the target thread exited before it could
477 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
478 // 0x00080000 each indicate a cancelled suspend request so they don't
479 // count as wait failures either.
480 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
481
482 class TraceSuspendDebugBits : public StackObj {
483 private:
484 JavaThread * jt;
485 bool is_wait;
486 bool called_by_wait; // meaningful when !is_wait
487 uint32_t * bits;
488
489 public:
490 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
491 uint32_t *_bits) {
492 jt = _jt;
493 is_wait = _is_wait;
494 called_by_wait = _called_by_wait;
495 bits = _bits;
496 }
497
498 ~TraceSuspendDebugBits() {
499 if (!is_wait) {
500 #if 1
501 // By default, don't trace bits for is_ext_suspend_completed() calls.
502 // That trace is very chatty.
503 return;
504 #else
505 if (!called_by_wait) {
506 // If tracing for is_ext_suspend_completed() is enabled, then only
507 // trace calls to it from wait_for_ext_suspend_completion()
508 return;
509 }
510 #endif
511 }
512
513 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
514 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
515 MutexLocker ml(Threads_lock); // needed for get_thread_name()
516 ResourceMark rm;
517
518 tty->print_cr(
519 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
520 jt->get_thread_name(), *bits);
521
522 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
523 }
524 }
525 }
526 };
527 #undef DEBUG_FALSE_BITS
528
529
530 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
531 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
532
533 bool did_trans_retry = false; // only do thread_in_native_trans retry once
534 bool do_trans_retry; // flag to force the retry
535
536 *bits |= 0x00000001;
537
538 do {
539 do_trans_retry = false;
540
541 if (is_exiting()) {
542 // Thread is in the process of exiting. This is always checked
543 // first to reduce the risk of dereferencing a freed JavaThread.
544 *bits |= 0x00000100;
545 return false;
546 }
547
548 if (!is_external_suspend()) {
549 // Suspend request is cancelled. This is always checked before
550 // is_ext_suspended() to reduce the risk of a rogue resume
551 // confusing the thread that made the suspend request.
552 *bits |= 0x00000200;
553 return false;
554 }
555
556 if (is_ext_suspended()) {
557 // thread is suspended
558 *bits |= 0x00000400;
559 return true;
560 }
561
562 // Now that we no longer do hard suspends of threads running
563 // native code, the target thread can be changing thread state
564 // while we are in this routine:
565 //
566 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
567 //
568 // We save a copy of the thread state as observed at this moment
569 // and make our decision about suspend completeness based on the
570 // copy. This closes the race where the thread state is seen as
571 // _thread_in_native_trans in the if-thread_blocked check, but is
572 // seen as _thread_blocked in if-thread_in_native_trans check.
573 JavaThreadState save_state = thread_state();
574
575 if (save_state == _thread_blocked && is_suspend_equivalent()) {
576 // If the thread's state is _thread_blocked and this blocking
577 // condition is known to be equivalent to a suspend, then we can
578 // consider the thread to be externally suspended. This means that
579 // the code that sets _thread_blocked has been modified to do
580 // self-suspension if the blocking condition releases. We also
581 // used to check for CONDVAR_WAIT here, but that is now covered by
582 // the _thread_blocked with self-suspension check.
583 //
584 // Return true since we wouldn't be here unless there was still an
585 // external suspend request.
586 *bits |= 0x00001000;
587 return true;
588 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
589 // Threads running native code will self-suspend on native==>VM/Java
590 // transitions. If its stack is walkable (should always be the case
591 // unless this function is called before the actual java_suspend()
592 // call), then the wait is done.
593 *bits |= 0x00002000;
594 return true;
595 } else if (!called_by_wait && !did_trans_retry &&
596 save_state == _thread_in_native_trans &&
597 frame_anchor()->walkable()) {
598 // The thread is transitioning from thread_in_native to another
599 // thread state. check_safepoint_and_suspend_for_native_trans()
600 // will force the thread to self-suspend. If it hasn't gotten
601 // there yet we may have caught the thread in-between the native
602 // code check above and the self-suspend. Lucky us. If we were
603 // called by wait_for_ext_suspend_completion(), then it
604 // will be doing the retries so we don't have to.
605 //
606 // Since we use the saved thread state in the if-statement above,
607 // there is a chance that the thread has already transitioned to
608 // _thread_blocked by the time we get here. In that case, we will
609 // make a single unnecessary pass through the logic below. This
610 // doesn't hurt anything since we still do the trans retry.
611
612 *bits |= 0x00004000;
613
614 // Once the thread leaves thread_in_native_trans for another
615 // thread state, we break out of this retry loop. We shouldn't
616 // need this flag to prevent us from getting back here, but
617 // sometimes paranoia is good.
618 did_trans_retry = true;
619
620 // We wait for the thread to transition to a more usable state.
621 for (int i = 1; i <= SuspendRetryCount; i++) {
622 // We used to do an "os::yield_all(i)" call here with the intention
623 // that yielding would increase on each retry. However, the parameter
624 // is ignored on Linux which means the yield didn't scale up. Waiting
625 // on the SR_lock below provides a much more predictable scale up for
626 // the delay. It also provides a simple/direct point to check for any
627 // safepoint requests from the VMThread
628
629 // temporarily drops SR_lock while doing wait with safepoint check
630 // (if we're a JavaThread - the WatcherThread can also call this)
631 // and increase delay with each retry
632 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
633
634 // check the actual thread state instead of what we saved above
635 if (thread_state() != _thread_in_native_trans) {
636 // the thread has transitioned to another thread state so
637 // try all the checks (except this one) one more time.
638 do_trans_retry = true;
639 break;
640 }
641 } // end retry loop
642
643
644 }
645 } while (do_trans_retry);
646
647 *bits |= 0x00000010;
648 return false;
649 }
650
651 //
652 // Wait for an external suspend request to complete (or be cancelled).
653 // Returns true if the thread is externally suspended and false otherwise.
654 //
655 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
656 uint32_t *bits) {
657 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
658 false /* !called_by_wait */, bits);
659
660 // local flag copies to minimize SR_lock hold time
661 bool is_suspended;
662 bool pending;
663 uint32_t reset_bits;
664
665 // set a marker so is_ext_suspend_completed() knows we are the caller
666 *bits |= 0x00010000;
667
668 // We use reset_bits to reinitialize the bits value at the top of
669 // each retry loop. This allows the caller to make use of any
670 // unused bits for their own marking purposes.
671 reset_bits = *bits;
672
673 {
674 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
675 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
676 delay, bits);
677 pending = is_external_suspend();
678 }
679 // must release SR_lock to allow suspension to complete
680
681 if (!pending) {
682 // A cancelled suspend request is the only false return from
683 // is_ext_suspend_completed() that keeps us from entering the
684 // retry loop.
685 *bits |= 0x00020000;
686 return false;
687 }
688
689 if (is_suspended) {
690 *bits |= 0x00040000;
691 return true;
692 }
693
694 for (int i = 1; i <= retries; i++) {
695 *bits = reset_bits; // reinit to only track last retry
696
697 // We used to do an "os::yield_all(i)" call here with the intention
698 // that yielding would increase on each retry. However, the parameter
699 // is ignored on Linux which means the yield didn't scale up. Waiting
700 // on the SR_lock below provides a much more predictable scale up for
701 // the delay. It also provides a simple/direct point to check for any
702 // safepoint requests from the VMThread
703
704 {
705 MutexLocker ml(SR_lock());
706 // wait with safepoint check (if we're a JavaThread - the WatcherThread
707 // can also call this) and increase delay with each retry
708 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
709
710 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
711 delay, bits);
712
713 // It is possible for the external suspend request to be cancelled
714 // (by a resume) before the actual suspend operation is completed.
715 // Refresh our local copy to see if we still need to wait.
716 pending = is_external_suspend();
717 }
718
719 if (!pending) {
720 // A cancelled suspend request is the only false return from
721 // is_ext_suspend_completed() that keeps us from staying in the
722 // retry loop.
723 *bits |= 0x00080000;
724 return false;
725 }
726
727 if (is_suspended) {
728 *bits |= 0x00100000;
729 return true;
730 }
731 } // end retry loop
732
733 // thread did not suspend after all our retries
734 *bits |= 0x00200000;
735 return false;
736 }
737
738 #ifndef PRODUCT
739 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
740
741 // This should not need to be atomic as the only way for simultaneous
742 // updates is via interrupts. Even then this should be rare or non-existent
743 // and we don't care that much anyway.
744
745 int index = _jmp_ring_index;
746 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
747 _jmp_ring[index]._target = (intptr_t) target;
748 _jmp_ring[index]._instruction = (intptr_t) instr;
749 _jmp_ring[index]._file = file;
750 _jmp_ring[index]._line = line;
751 }
752 #endif /* PRODUCT */
753
754 // Called by flat profiler
755 // Callers have already called wait_for_ext_suspend_completion
756 // The assertion for that is currently too complex to put here:
757 bool JavaThread::profile_last_Java_frame(frame* _fr) {
758 bool gotframe = false;
759 // self suspension saves needed state.
760 if (has_last_Java_frame() && _anchor.walkable()) {
761 *_fr = pd_last_frame();
762 gotframe = true;
763 }
764 return gotframe;
765 }
766
767 void Thread::interrupt(Thread* thread) {
768 trace("interrupt", thread);
769 debug_only(check_for_dangling_thread_pointer(thread);)
770 os::interrupt(thread);
771 }
772
773 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
774 trace("is_interrupted", thread);
775 debug_only(check_for_dangling_thread_pointer(thread);)
776 // Note: If clear_interrupted==false, this simply fetches and
777 // returns the value of the field osthread()->interrupted().
778 return os::is_interrupted(thread, clear_interrupted);
779 }
780
781
782 // GC Support
783 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
784 jint thread_parity = _oops_do_parity;
785 if (thread_parity != strong_roots_parity) {
786 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
787 if (res == thread_parity) {
788 return true;
789 } else {
790 guarantee(res == strong_roots_parity, "Or else what?");
791 assert(SharedHeap::heap()->workers()->active_workers() > 0,
792 "Should only fail when parallel.");
793 return false;
794 }
795 }
796 assert(SharedHeap::heap()->workers()->active_workers() > 0,
797 "Should only fail when parallel.");
798 return false;
799 }
800
801 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
802 active_handles()->oops_do(f);
803 // Do oop for ThreadShadow
804 f->do_oop((oop*)&_pending_exception);
805 handle_area()->oops_do(f);
806 }
807
808 void Thread::nmethods_do(CodeBlobClosure* cf) {
809 // no nmethods in a generic thread...
810 }
811
812 void Thread::metadata_do(void f(Metadata*)) {
813 if (metadata_handles() != NULL) {
814 for (int i = 0; i< metadata_handles()->length(); i++) {
815 f(metadata_handles()->at(i));
816 }
817 }
818 }
819
820 void Thread::print_on(outputStream* st) const {
821 // get_priority assumes osthread initialized
822 if (osthread() != NULL) {
823 int os_prio;
824 if (os::get_native_priority(this, &os_prio) == OS_OK) {
825 st->print("os_prio=%d ", os_prio);
826 }
827 st->print("tid=" INTPTR_FORMAT " ", this);
828 osthread()->print_on(st);
829 }
830 debug_only(if (WizardMode) print_owned_locks_on(st);)
831 }
832
833 // Thread::print_on_error() is called by fatal error handler. Don't use
834 // any lock or allocate memory.
835 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
836 if (is_VM_thread()) st->print("VMThread");
837 else if (is_Compiler_thread()) st->print("CompilerThread");
838 else if (is_Java_thread()) st->print("JavaThread");
839 else if (is_GC_task_thread()) st->print("GCTaskThread");
840 else if (is_Watcher_thread()) st->print("WatcherThread");
841 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
842 else st->print("Thread");
843
844 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
845 _stack_base - _stack_size, _stack_base);
846
847 if (osthread()) {
848 st->print(" [id=%d]", osthread()->thread_id());
849 }
850 }
851
852 #ifdef ASSERT
853 void Thread::print_owned_locks_on(outputStream* st) const {
854 Monitor *cur = _owned_locks;
855 if (cur == NULL) {
856 st->print(" (no locks) ");
857 } else {
858 st->print_cr(" Locks owned:");
859 while (cur) {
860 cur->print_on(st);
861 cur = cur->next();
862 }
863 }
864 }
865
866 static int ref_use_count = 0;
867
868 bool Thread::owns_locks_but_compiled_lock() const {
869 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
870 if (cur != Compile_lock) return true;
871 }
872 return false;
873 }
874
875
876 #endif
877
878 #ifndef PRODUCT
879
880 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
881 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
882 // no threads which allow_vm_block's are held
883 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
884 // Check if current thread is allowed to block at a safepoint
885 if (!(_allow_safepoint_count == 0))
886 fatal("Possible safepoint reached by thread that does not allow it");
887 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
888 fatal("LEAF method calling lock?");
889 }
890
891 #ifdef ASSERT
892 if (potential_vm_operation && is_Java_thread()
893 && !Universe::is_bootstrapping()) {
894 // Make sure we do not hold any locks that the VM thread also uses.
895 // This could potentially lead to deadlocks
896 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
897 // Threads_lock is special, since the safepoint synchronization will not start before this is
898 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
899 // since it is used to transfer control between JavaThreads and the VMThread
900 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
901 if ((cur->allow_vm_block() &&
902 cur != Threads_lock &&
903 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
904 cur != VMOperationRequest_lock &&
905 cur != VMOperationQueue_lock) ||
906 cur->rank() == Mutex::special) {
907 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
908 }
909 }
910 }
911
912 if (GCALotAtAllSafepoints) {
913 // We could enter a safepoint here and thus have a gc
914 InterfaceSupport::check_gc_alot();
915 }
916 #endif
917 }
918 #endif
919
920 bool Thread::is_in_stack(address adr) const {
921 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
922 address end = os::current_stack_pointer();
923 // Allow non Java threads to call this without stack_base
924 if (_stack_base == NULL) return true;
925 if (stack_base() >= adr && adr >= end) return true;
926
927 return false;
928 }
929
930
931 bool Thread::is_in_usable_stack(address adr) const {
932 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
933 size_t usable_stack_size = _stack_size - stack_guard_size;
934
935 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
936 }
937
938
939 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
940 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
941 // used for compilation in the future. If that change is made, the need for these methods
942 // should be revisited, and they should be removed if possible.
943
944 bool Thread::is_lock_owned(address adr) const {
945 return on_local_stack(adr);
946 }
947
948 bool Thread::set_as_starting_thread() {
949 // NOTE: this must be called inside the main thread.
950 return os::create_main_thread((JavaThread*)this);
951 }
952
953 static void initialize_class(Symbol* class_name, TRAPS) {
954 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
955 InstanceKlass::cast(klass)->initialize(CHECK);
956 }
957
958
959 // Creates the initial ThreadGroup
960 static Handle create_initial_thread_group(TRAPS) {
961 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
962 instanceKlassHandle klass (THREAD, k);
963
964 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
965 {
966 JavaValue result(T_VOID);
967 JavaCalls::call_special(&result,
968 system_instance,
969 klass,
970 vmSymbols::object_initializer_name(),
971 vmSymbols::void_method_signature(),
972 CHECK_NH);
973 }
974 Universe::set_system_thread_group(system_instance());
975
976 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
977 {
978 JavaValue result(T_VOID);
979 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
980 JavaCalls::call_special(&result,
981 main_instance,
982 klass,
983 vmSymbols::object_initializer_name(),
984 vmSymbols::threadgroup_string_void_signature(),
985 system_instance,
986 string,
987 CHECK_NH);
988 }
989 return main_instance;
990 }
991
992 // Creates the initial Thread
993 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
994 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
995 instanceKlassHandle klass (THREAD, k);
996 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
997
998 java_lang_Thread::set_thread(thread_oop(), thread);
999 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1000 thread->set_threadObj(thread_oop());
1001
1002 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1003
1004 JavaValue result(T_VOID);
1005 JavaCalls::call_special(&result, thread_oop,
1006 klass,
1007 vmSymbols::object_initializer_name(),
1008 vmSymbols::threadgroup_string_void_signature(),
1009 thread_group,
1010 string,
1011 CHECK_NULL);
1012 return thread_oop();
1013 }
1014
1015 static void call_initializeSystemClass(TRAPS) {
1016 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1017 instanceKlassHandle klass (THREAD, k);
1018
1019 JavaValue result(T_VOID);
1020 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1021 vmSymbols::void_method_signature(), CHECK);
1022 }
1023
1024 char java_runtime_name[128] = "";
1025 char java_runtime_version[128] = "";
1026
1027 // extract the JRE name from sun.misc.Version.java_runtime_name
1028 static const char* get_java_runtime_name(TRAPS) {
1029 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1030 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1031 fieldDescriptor fd;
1032 bool found = k != NULL &&
1033 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1034 vmSymbols::string_signature(), &fd);
1035 if (found) {
1036 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1037 if (name_oop == NULL)
1038 return NULL;
1039 const char* name = java_lang_String::as_utf8_string(name_oop,
1040 java_runtime_name,
1041 sizeof(java_runtime_name));
1042 return name;
1043 } else {
1044 return NULL;
1045 }
1046 }
1047
1048 // extract the JRE version from sun.misc.Version.java_runtime_version
1049 static const char* get_java_runtime_version(TRAPS) {
1050 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1051 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1052 fieldDescriptor fd;
1053 bool found = k != NULL &&
1054 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1055 vmSymbols::string_signature(), &fd);
1056 if (found) {
1057 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1058 if (name_oop == NULL)
1059 return NULL;
1060 const char* name = java_lang_String::as_utf8_string(name_oop,
1061 java_runtime_version,
1062 sizeof(java_runtime_version));
1063 return name;
1064 } else {
1065 return NULL;
1066 }
1067 }
1068
1069 // General purpose hook into Java code, run once when the VM is initialized.
1070 // The Java library method itself may be changed independently from the VM.
1071 static void call_postVMInitHook(TRAPS) {
1072 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1073 instanceKlassHandle klass (THREAD, k);
1074 if (klass.not_null()) {
1075 JavaValue result(T_VOID);
1076 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1077 vmSymbols::void_method_signature(),
1078 CHECK);
1079 }
1080 }
1081
1082 static void reset_vm_info_property(TRAPS) {
1083 // the vm info string
1084 ResourceMark rm(THREAD);
1085 const char *vm_info = VM_Version::vm_info_string();
1086
1087 // java.lang.System class
1088 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1089 instanceKlassHandle klass (THREAD, k);
1090
1091 // setProperty arguments
1092 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1093 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1094
1095 // return value
1096 JavaValue r(T_OBJECT);
1097
1098 // public static String setProperty(String key, String value);
1099 JavaCalls::call_static(&r,
1100 klass,
1101 vmSymbols::setProperty_name(),
1102 vmSymbols::string_string_string_signature(),
1103 key_str,
1104 value_str,
1105 CHECK);
1106 }
1107
1108
1109 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1110 assert(thread_group.not_null(), "thread group should be specified");
1111 assert(threadObj() == NULL, "should only create Java thread object once");
1112
1113 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1114 instanceKlassHandle klass (THREAD, k);
1115 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1116
1117 java_lang_Thread::set_thread(thread_oop(), this);
1118 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1119 set_threadObj(thread_oop());
1120
1121 JavaValue result(T_VOID);
1122 if (thread_name != NULL) {
1123 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1124 // Thread gets assigned specified name and null target
1125 JavaCalls::call_special(&result,
1126 thread_oop,
1127 klass,
1128 vmSymbols::object_initializer_name(),
1129 vmSymbols::threadgroup_string_void_signature(),
1130 thread_group, // Argument 1
1131 name, // Argument 2
1132 THREAD);
1133 } else {
1134 // Thread gets assigned name "Thread-nnn" and null target
1135 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1136 JavaCalls::call_special(&result,
1137 thread_oop,
1138 klass,
1139 vmSymbols::object_initializer_name(),
1140 vmSymbols::threadgroup_runnable_void_signature(),
1141 thread_group, // Argument 1
1142 Handle(), // Argument 2
1143 THREAD);
1144 }
1145
1146
1147 if (daemon) {
1148 java_lang_Thread::set_daemon(thread_oop());
1149 }
1150
1151 if (HAS_PENDING_EXCEPTION) {
1152 return;
1153 }
1154
1155 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1156 Handle threadObj(this, this->threadObj());
1157
1158 JavaCalls::call_special(&result,
1159 thread_group,
1160 group,
1161 vmSymbols::add_method_name(),
1162 vmSymbols::thread_void_signature(),
1163 threadObj, // Arg 1
1164 THREAD);
1165
1166
1167 }
1168
1169 // NamedThread -- non-JavaThread subclasses with multiple
1170 // uniquely named instances should derive from this.
1171 NamedThread::NamedThread() : Thread() {
1172 _name = NULL;
1173 _processed_thread = NULL;
1174 }
1175
1176 NamedThread::~NamedThread() {
1177 if (_name != NULL) {
1178 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1179 _name = NULL;
1180 }
1181 }
1182
1183 void NamedThread::set_name(const char* format, ...) {
1184 guarantee(_name == NULL, "Only get to set name once.");
1185 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1186 guarantee(_name != NULL, "alloc failure");
1187 va_list ap;
1188 va_start(ap, format);
1189 jio_vsnprintf(_name, max_name_len, format, ap);
1190 va_end(ap);
1191 }
1192
1193 void NamedThread::print_on(outputStream* st) const {
1194 st->print("\"%s\" ", name());
1195 Thread::print_on(st);
1196 st->cr();
1197 }
1198
1199
1200 // ======= WatcherThread ========
1201
1202 // The watcher thread exists to simulate timer interrupts. It should
1203 // be replaced by an abstraction over whatever native support for
1204 // timer interrupts exists on the platform.
1205
1206 WatcherThread* WatcherThread::_watcher_thread = NULL;
1207 bool WatcherThread::_startable = false;
1208 volatile bool WatcherThread::_should_terminate = false;
1209
1210 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1211 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1212 if (os::create_thread(this, os::watcher_thread)) {
1213 _watcher_thread = this;
1214
1215 // Set the watcher thread to the highest OS priority which should not be
1216 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1217 // is created. The only normal thread using this priority is the reference
1218 // handler thread, which runs for very short intervals only.
1219 // If the VMThread's priority is not lower than the WatcherThread profiling
1220 // will be inaccurate.
1221 os::set_priority(this, MaxPriority);
1222 if (!DisableStartThread) {
1223 os::start_thread(this);
1224 }
1225 }
1226 }
1227
1228 int WatcherThread::sleep() const {
1229 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1230
1231 // remaining will be zero if there are no tasks,
1232 // causing the WatcherThread to sleep until a task is
1233 // enrolled
1234 int remaining = PeriodicTask::time_to_wait();
1235 int time_slept = 0;
1236
1237 // we expect this to timeout - we only ever get unparked when
1238 // we should terminate or when a new task has been enrolled
1239 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1240
1241 jlong time_before_loop = os::javaTimeNanos();
1242
1243 for (;;) {
1244 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1245 jlong now = os::javaTimeNanos();
1246
1247 if (remaining == 0) {
1248 // if we didn't have any tasks we could have waited for a long time
1249 // consider the time_slept zero and reset time_before_loop
1250 time_slept = 0;
1251 time_before_loop = now;
1252 } else {
1253 // need to recalculate since we might have new tasks in _tasks
1254 time_slept = (int) ((now - time_before_loop) / 1000000);
1255 }
1256
1257 // Change to task list or spurious wakeup of some kind
1258 if (timedout || _should_terminate) {
1259 break;
1260 }
1261
1262 remaining = PeriodicTask::time_to_wait();
1263 if (remaining == 0) {
1264 // Last task was just disenrolled so loop around and wait until
1265 // another task gets enrolled
1266 continue;
1267 }
1268
1269 remaining -= time_slept;
1270 if (remaining <= 0)
1271 break;
1272 }
1273
1274 return time_slept;
1275 }
1276
1277 void WatcherThread::run() {
1278 assert(this == watcher_thread(), "just checking");
1279
1280 this->record_stack_base_and_size();
1281 this->initialize_thread_local_storage();
1282 this->set_active_handles(JNIHandleBlock::allocate_block());
1283 while (!_should_terminate) {
1284 assert(watcher_thread() == Thread::current(), "thread consistency check");
1285 assert(watcher_thread() == this, "thread consistency check");
1286
1287 // Calculate how long it'll be until the next PeriodicTask work
1288 // should be done, and sleep that amount of time.
1289 int time_waited = sleep();
1290
1291 if (is_error_reported()) {
1292 // A fatal error has happened, the error handler(VMError::report_and_die)
1293 // should abort JVM after creating an error log file. However in some
1294 // rare cases, the error handler itself might deadlock. Here we try to
1295 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1296 //
1297 // This code is in WatcherThread because WatcherThread wakes up
1298 // periodically so the fatal error handler doesn't need to do anything;
1299 // also because the WatcherThread is less likely to crash than other
1300 // threads.
1301
1302 for (;;) {
1303 if (!ShowMessageBoxOnError
1304 && (OnError == NULL || OnError[0] == '\0')
1305 && Arguments::abort_hook() == NULL) {
1306 os::sleep(this, 2 * 60 * 1000, false);
1307 fdStream err(defaultStream::output_fd());
1308 err.print_raw_cr("# [ timer expired, abort... ]");
1309 // skip atexit/vm_exit/vm_abort hooks
1310 os::die();
1311 }
1312
1313 // Wake up 5 seconds later, the fatal handler may reset OnError or
1314 // ShowMessageBoxOnError when it is ready to abort.
1315 os::sleep(this, 5 * 1000, false);
1316 }
1317 }
1318
1319 PeriodicTask::real_time_tick(time_waited);
1320 }
1321
1322 // Signal that it is terminated
1323 {
1324 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1325 _watcher_thread = NULL;
1326 Terminator_lock->notify();
1327 }
1328
1329 // Thread destructor usually does this..
1330 ThreadLocalStorage::set_thread(NULL);
1331 }
1332
1333 void WatcherThread::start() {
1334 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1335
1336 if (watcher_thread() == NULL && _startable) {
1337 _should_terminate = false;
1338 // Create the single instance of WatcherThread
1339 new WatcherThread();
1340 }
1341 }
1342
1343 void WatcherThread::make_startable() {
1344 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1345 _startable = true;
1346 }
1347
1348 void WatcherThread::stop() {
1349 // Get the PeriodicTask_lock if we can. If we cannot, then the
1350 // WatcherThread is using it and we don't want to block on that lock
1351 // here because that might cause a safepoint deadlock depending on
1352 // what the current WatcherThread tasks are doing.
1353 bool have_lock = PeriodicTask_lock->try_lock();
1354
1355 _should_terminate = true;
1356 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1357
1358 if (have_lock) {
1359 WatcherThread* watcher = watcher_thread();
1360 if (watcher != NULL) {
1361 // If we managed to get the lock, then we should unpark the
1362 // WatcherThread so that it can see we want it to stop.
1363 watcher->unpark();
1364 }
1365
1366 PeriodicTask_lock->unlock();
1367 }
1368
1369 // it is ok to take late safepoints here, if needed
1370 MutexLocker mu(Terminator_lock);
1371
1372 while (watcher_thread() != NULL) {
1373 // This wait should make safepoint checks, wait without a timeout,
1374 // and wait as a suspend-equivalent condition.
1375 //
1376 // Note: If the FlatProfiler is running, then this thread is waiting
1377 // for the WatcherThread to terminate and the WatcherThread, via the
1378 // FlatProfiler task, is waiting for the external suspend request on
1379 // this thread to complete. wait_for_ext_suspend_completion() will
1380 // eventually timeout, but that takes time. Making this wait a
1381 // suspend-equivalent condition solves that timeout problem.
1382 //
1383 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1384 Mutex::_as_suspend_equivalent_flag);
1385 }
1386 }
1387
1388 void WatcherThread::unpark() {
1389 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1390 PeriodicTask_lock->notify();
1391 }
1392
1393 void WatcherThread::print_on(outputStream* st) const {
1394 st->print("\"%s\" ", name());
1395 Thread::print_on(st);
1396 st->cr();
1397 }
1398
1399 // ======= JavaThread ========
1400
1401 // A JavaThread is a normal Java thread
1402
1403 void JavaThread::initialize() {
1404 // Initialize fields
1405
1406 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1407 set_claimed_par_id(UINT_MAX);
1408
1409 set_saved_exception_pc(NULL);
1410 set_threadObj(NULL);
1411 _anchor.clear();
1412 set_entry_point(NULL);
1413 set_jni_functions(jni_functions());
1414 set_callee_target(NULL);
1415 set_vm_result(NULL);
1416 set_vm_result_2(NULL);
1417 set_vframe_array_head(NULL);
1418 set_vframe_array_last(NULL);
1419 set_deferred_locals(NULL);
1420 set_deopt_mark(NULL);
1421 set_deopt_nmethod(NULL);
1422 clear_must_deopt_id();
1423 set_monitor_chunks(NULL);
1424 set_next(NULL);
1425 set_thread_state(_thread_new);
1426 #if INCLUDE_NMT
1427 set_recorder(NULL);
1428 #endif
1429 _terminated = _not_terminated;
1430 _privileged_stack_top = NULL;
1431 _array_for_gc = NULL;
1432 _suspend_equivalent = false;
1433 _in_deopt_handler = 0;
1434 _doing_unsafe_access = false;
1435 _stack_guard_state = stack_guard_unused;
1436 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1437 _exception_pc = 0;
1438 _exception_handler_pc = 0;
1439 _is_method_handle_return = 0;
1440 _jvmti_thread_state= NULL;
1441 _should_post_on_exceptions_flag = JNI_FALSE;
1442 _jvmti_get_loaded_classes_closure = NULL;
1443 _interp_only_mode = 0;
1444 _special_runtime_exit_condition = _no_async_condition;
1445 _pending_async_exception = NULL;
1446 _thread_stat = NULL;
1447 _thread_stat = new ThreadStatistics();
1448 _blocked_on_compilation = false;
1449 _jni_active_critical = 0;
1450 _pending_jni_exception_check_fn = NULL;
1451 _do_not_unlock_if_synchronized = false;
1452 _cached_monitor_info = NULL;
1453 _parker = Parker::Allocate(this);
1454
1455 #ifndef PRODUCT
1456 _jmp_ring_index = 0;
1457 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1458 record_jump(NULL, NULL, NULL, 0);
1459 }
1460 #endif /* PRODUCT */
1461
1462 set_thread_profiler(NULL);
1463 if (FlatProfiler::is_active()) {
1464 // This is where we would decide to either give each thread it's own profiler
1465 // or use one global one from FlatProfiler,
1466 // or up to some count of the number of profiled threads, etc.
1467 ThreadProfiler* pp = new ThreadProfiler();
1468 pp->engage();
1469 set_thread_profiler(pp);
1470 }
1471
1472 // Setup safepoint state info for this thread
1473 ThreadSafepointState::create(this);
1474
1475 debug_only(_java_call_counter = 0);
1476
1477 // JVMTI PopFrame support
1478 _popframe_condition = popframe_inactive;
1479 _popframe_preserved_args = NULL;
1480 _popframe_preserved_args_size = 0;
1481
1482 pd_initialize();
1483 }
1484
1485 #if INCLUDE_ALL_GCS
1486 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1487 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1488 #endif // INCLUDE_ALL_GCS
1489
1490 JavaThread::JavaThread(bool is_attaching_via_jni) :
1491 Thread()
1492 #if INCLUDE_ALL_GCS
1493 , _satb_mark_queue(&_satb_mark_queue_set),
1494 _dirty_card_queue(&_dirty_card_queue_set)
1495 #endif // INCLUDE_ALL_GCS
1496 {
1497 initialize();
1498 if (is_attaching_via_jni) {
1499 _jni_attach_state = _attaching_via_jni;
1500 } else {
1501 _jni_attach_state = _not_attaching_via_jni;
1502 }
1503 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1504 _safepoint_visible = false;
1505 }
1506
1507 bool JavaThread::reguard_stack(address cur_sp) {
1508 if (_stack_guard_state != stack_guard_yellow_disabled) {
1509 return true; // Stack already guarded or guard pages not needed.
1510 }
1511
1512 if (register_stack_overflow()) {
1513 // For those architectures which have separate register and
1514 // memory stacks, we must check the register stack to see if
1515 // it has overflowed.
1516 return false;
1517 }
1518
1519 // Java code never executes within the yellow zone: the latter is only
1520 // there to provoke an exception during stack banging. If java code
1521 // is executing there, either StackShadowPages should be larger, or
1522 // some exception code in c1, c2 or the interpreter isn't unwinding
1523 // when it should.
1524 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1525
1526 enable_stack_yellow_zone();
1527 return true;
1528 }
1529
1530 bool JavaThread::reguard_stack(void) {
1531 return reguard_stack(os::current_stack_pointer());
1532 }
1533
1534
1535 void JavaThread::block_if_vm_exited() {
1536 if (_terminated == _vm_exited) {
1537 // _vm_exited is set at safepoint, and Threads_lock is never released
1538 // we will block here forever
1539 Threads_lock->lock_without_safepoint_check();
1540 ShouldNotReachHere();
1541 }
1542 }
1543
1544
1545 // Remove this ifdef when C1 is ported to the compiler interface.
1546 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1547
1548 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1549 Thread()
1550 #if INCLUDE_ALL_GCS
1551 , _satb_mark_queue(&_satb_mark_queue_set),
1552 _dirty_card_queue(&_dirty_card_queue_set)
1553 #endif // INCLUDE_ALL_GCS
1554 {
1555 if (TraceThreadEvents) {
1556 tty->print_cr("creating thread %p", this);
1557 }
1558 initialize();
1559 _jni_attach_state = _not_attaching_via_jni;
1560 set_entry_point(entry_point);
1561 // Create the native thread itself.
1562 // %note runtime_23
1563 os::ThreadType thr_type = os::java_thread;
1564 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1565 os::java_thread;
1566 os::create_thread(this, thr_type, stack_sz);
1567 _safepoint_visible = false;
1568 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1569 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1570 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1571 // the exception consists of creating the exception object & initializing it, initialization
1572 // will leave the VM via a JavaCall and then all locks must be unlocked).
1573 //
1574 // The thread is still suspended when we reach here. Thread must be explicit started
1575 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1576 // by calling Threads:add. The reason why this is not done here, is because the thread
1577 // object must be fully initialized (take a look at JVM_Start)
1578 }
1579
1580 JavaThread::~JavaThread() {
1581 if (TraceThreadEvents) {
1582 tty->print_cr("terminate thread %p", this);
1583 }
1584
1585 // By now, this thread should already be invisible to safepoint,
1586 // and its per-thread recorder also collected.
1587 assert(!is_safepoint_visible(), "wrong state");
1588 #if INCLUDE_NMT
1589 assert(get_recorder() == NULL, "Already collected");
1590 #endif // INCLUDE_NMT
1591
1592 // JSR166 -- return the parker to the free list
1593 Parker::Release(_parker);
1594 _parker = NULL;
1595
1596 // Free any remaining previous UnrollBlock
1597 vframeArray* old_array = vframe_array_last();
1598
1599 if (old_array != NULL) {
1600 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1601 old_array->set_unroll_block(NULL);
1602 delete old_info;
1603 delete old_array;
1604 }
1605
1606 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1607 if (deferred != NULL) {
1608 // This can only happen if thread is destroyed before deoptimization occurs.
1609 assert(deferred->length() != 0, "empty array!");
1610 do {
1611 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1612 deferred->remove_at(0);
1613 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1614 delete dlv;
1615 } while (deferred->length() != 0);
1616 delete deferred;
1617 }
1618
1619 // All Java related clean up happens in exit
1620 ThreadSafepointState::destroy(this);
1621 if (_thread_profiler != NULL) delete _thread_profiler;
1622 if (_thread_stat != NULL) delete _thread_stat;
1623 }
1624
1625
1626 // The first routine called by a new Java thread
1627 void JavaThread::run() {
1628 // initialize thread-local alloc buffer related fields
1629 this->initialize_tlab();
1630
1631 // used to test validity of stack trace backs
1632 this->record_base_of_stack_pointer();
1633
1634 // Record real stack base and size.
1635 this->record_stack_base_and_size();
1636
1637 // Initialize thread local storage; set before calling MutexLocker
1638 this->initialize_thread_local_storage();
1639
1640 this->create_stack_guard_pages();
1641
1642 this->cache_global_variables();
1643
1644 // Thread is now sufficient initialized to be handled by the safepoint code as being
1645 // in the VM. Change thread state from _thread_new to _thread_in_vm
1646 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1647
1648 assert(JavaThread::current() == this, "sanity check");
1649 assert(!Thread::current()->owns_locks(), "sanity check");
1650
1651 DTRACE_THREAD_PROBE(start, this);
1652
1653 // This operation might block. We call that after all safepoint checks for a new thread has
1654 // been completed.
1655 this->set_active_handles(JNIHandleBlock::allocate_block());
1656
1657 if (JvmtiExport::should_post_thread_life()) {
1658 JvmtiExport::post_thread_start(this);
1659 }
1660
1661 EventThreadStart event;
1662 if (event.should_commit()) {
1663 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1664 event.commit();
1665 }
1666
1667 // We call another function to do the rest so we are sure that the stack addresses used
1668 // from there will be lower than the stack base just computed
1669 thread_main_inner();
1670
1671 // Note, thread is no longer valid at this point!
1672 }
1673
1674
1675 void JavaThread::thread_main_inner() {
1676 assert(JavaThread::current() == this, "sanity check");
1677 assert(this->threadObj() != NULL, "just checking");
1678
1679 // Execute thread entry point unless this thread has a pending exception
1680 // or has been stopped before starting.
1681 // Note: Due to JVM_StopThread we can have pending exceptions already!
1682 if (!this->has_pending_exception() &&
1683 !java_lang_Thread::is_stillborn(this->threadObj())) {
1684 {
1685 ResourceMark rm(this);
1686 this->set_native_thread_name(this->get_thread_name());
1687 }
1688 HandleMark hm(this);
1689 this->entry_point()(this, this);
1690 }
1691
1692 DTRACE_THREAD_PROBE(stop, this);
1693
1694 this->exit(false);
1695 delete this;
1696 }
1697
1698
1699 static void ensure_join(JavaThread* thread) {
1700 // We do not need to grap the Threads_lock, since we are operating on ourself.
1701 Handle threadObj(thread, thread->threadObj());
1702 assert(threadObj.not_null(), "java thread object must exist");
1703 ObjectLocker lock(threadObj, thread);
1704 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1705 thread->clear_pending_exception();
1706 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1707 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1708 // Clear the native thread instance - this makes isAlive return false and allows the join()
1709 // to complete once we've done the notify_all below
1710 java_lang_Thread::set_thread(threadObj(), NULL);
1711 lock.notify_all(thread);
1712 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1713 thread->clear_pending_exception();
1714 }
1715
1716
1717 // For any new cleanup additions, please check to see if they need to be applied to
1718 // cleanup_failed_attach_current_thread as well.
1719 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1720 assert(this == JavaThread::current(), "thread consistency check");
1721
1722 HandleMark hm(this);
1723 Handle uncaught_exception(this, this->pending_exception());
1724 this->clear_pending_exception();
1725 Handle threadObj(this, this->threadObj());
1726 assert(threadObj.not_null(), "Java thread object should be created");
1727
1728 if (get_thread_profiler() != NULL) {
1729 get_thread_profiler()->disengage();
1730 ResourceMark rm;
1731 get_thread_profiler()->print(get_thread_name());
1732 }
1733
1734
1735 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1736 {
1737 EXCEPTION_MARK;
1738
1739 CLEAR_PENDING_EXCEPTION;
1740 }
1741 if (!destroy_vm) {
1742 if (uncaught_exception.not_null()) {
1743 EXCEPTION_MARK;
1744 // Call method Thread.dispatchUncaughtException().
1745 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1746 JavaValue result(T_VOID);
1747 JavaCalls::call_virtual(&result,
1748 threadObj, thread_klass,
1749 vmSymbols::dispatchUncaughtException_name(),
1750 vmSymbols::throwable_void_signature(),
1751 uncaught_exception,
1752 THREAD);
1753 if (HAS_PENDING_EXCEPTION) {
1754 ResourceMark rm(this);
1755 jio_fprintf(defaultStream::error_stream(),
1756 "\nException: %s thrown from the UncaughtExceptionHandler"
1757 " in thread \"%s\"\n",
1758 pending_exception()->klass()->external_name(),
1759 get_thread_name());
1760 CLEAR_PENDING_EXCEPTION;
1761 }
1762 }
1763
1764 // Called before the java thread exit since we want to read info
1765 // from java_lang_Thread object
1766 EventThreadEnd event;
1767 if (event.should_commit()) {
1768 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1769 event.commit();
1770 }
1771
1772 // Call after last event on thread
1773 EVENT_THREAD_EXIT(this);
1774
1775 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1776 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1777 // is deprecated anyhow.
1778 if (!is_Compiler_thread()) {
1779 int count = 3;
1780 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1781 EXCEPTION_MARK;
1782 JavaValue result(T_VOID);
1783 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1784 JavaCalls::call_virtual(&result,
1785 threadObj, thread_klass,
1786 vmSymbols::exit_method_name(),
1787 vmSymbols::void_method_signature(),
1788 THREAD);
1789 CLEAR_PENDING_EXCEPTION;
1790 }
1791 }
1792 // notify JVMTI
1793 if (JvmtiExport::should_post_thread_life()) {
1794 JvmtiExport::post_thread_end(this);
1795 }
1796
1797 // We have notified the agents that we are exiting, before we go on,
1798 // we must check for a pending external suspend request and honor it
1799 // in order to not surprise the thread that made the suspend request.
1800 while (true) {
1801 {
1802 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1803 if (!is_external_suspend()) {
1804 set_terminated(_thread_exiting);
1805 ThreadService::current_thread_exiting(this);
1806 break;
1807 }
1808 // Implied else:
1809 // Things get a little tricky here. We have a pending external
1810 // suspend request, but we are holding the SR_lock so we
1811 // can't just self-suspend. So we temporarily drop the lock
1812 // and then self-suspend.
1813 }
1814
1815 ThreadBlockInVM tbivm(this);
1816 java_suspend_self();
1817
1818 // We're done with this suspend request, but we have to loop around
1819 // and check again. Eventually we will get SR_lock without a pending
1820 // external suspend request and will be able to mark ourselves as
1821 // exiting.
1822 }
1823 // no more external suspends are allowed at this point
1824 } else {
1825 // before_exit() has already posted JVMTI THREAD_END events
1826 }
1827
1828 // Notify waiters on thread object. This has to be done after exit() is called
1829 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1830 // group should have the destroyed bit set before waiters are notified).
1831 ensure_join(this);
1832 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1833
1834 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1835 // held by this thread must be released. A detach operation must only
1836 // get here if there are no Java frames on the stack. Therefore, any
1837 // owned monitors at this point MUST be JNI-acquired monitors which are
1838 // pre-inflated and in the monitor cache.
1839 //
1840 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1841 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1842 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1843 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1844 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1845 }
1846
1847 // These things needs to be done while we are still a Java Thread. Make sure that thread
1848 // is in a consistent state, in case GC happens
1849 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1850
1851 if (active_handles() != NULL) {
1852 JNIHandleBlock* block = active_handles();
1853 set_active_handles(NULL);
1854 JNIHandleBlock::release_block(block);
1855 }
1856
1857 if (free_handle_block() != NULL) {
1858 JNIHandleBlock* block = free_handle_block();
1859 set_free_handle_block(NULL);
1860 JNIHandleBlock::release_block(block);
1861 }
1862
1863 // These have to be removed while this is still a valid thread.
1864 remove_stack_guard_pages();
1865
1866 if (UseTLAB) {
1867 tlab().make_parsable(true); // retire TLAB
1868 }
1869
1870 if (JvmtiEnv::environments_might_exist()) {
1871 JvmtiExport::cleanup_thread(this);
1872 }
1873
1874 // We must flush any deferred card marks before removing a thread from
1875 // the list of active threads.
1876 Universe::heap()->flush_deferred_store_barrier(this);
1877 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1878
1879 #if INCLUDE_ALL_GCS
1880 // We must flush the G1-related buffers before removing a thread
1881 // from the list of active threads. We must do this after any deferred
1882 // card marks have been flushed (above) so that any entries that are
1883 // added to the thread's dirty card queue as a result are not lost.
1884 if (UseG1GC) {
1885 flush_barrier_queues();
1886 }
1887 #endif // INCLUDE_ALL_GCS
1888
1889 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1890 Threads::remove(this);
1891 }
1892
1893 #if INCLUDE_ALL_GCS
1894 // Flush G1-related queues.
1895 void JavaThread::flush_barrier_queues() {
1896 satb_mark_queue().flush();
1897 dirty_card_queue().flush();
1898 }
1899
1900 void JavaThread::initialize_queues() {
1901 assert(!SafepointSynchronize::is_at_safepoint(),
1902 "we should not be at a safepoint");
1903
1904 ObjPtrQueue& satb_queue = satb_mark_queue();
1905 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1906 // The SATB queue should have been constructed with its active
1907 // field set to false.
1908 assert(!satb_queue.is_active(), "SATB queue should not be active");
1909 assert(satb_queue.is_empty(), "SATB queue should be empty");
1910 // If we are creating the thread during a marking cycle, we should
1911 // set the active field of the SATB queue to true.
1912 if (satb_queue_set.is_active()) {
1913 satb_queue.set_active(true);
1914 }
1915
1916 DirtyCardQueue& dirty_queue = dirty_card_queue();
1917 // The dirty card queue should have been constructed with its
1918 // active field set to true.
1919 assert(dirty_queue.is_active(), "dirty card queue should be active");
1920 }
1921 #endif // INCLUDE_ALL_GCS
1922
1923 void JavaThread::cleanup_failed_attach_current_thread() {
1924 if (get_thread_profiler() != NULL) {
1925 get_thread_profiler()->disengage();
1926 ResourceMark rm;
1927 get_thread_profiler()->print(get_thread_name());
1928 }
1929
1930 if (active_handles() != NULL) {
1931 JNIHandleBlock* block = active_handles();
1932 set_active_handles(NULL);
1933 JNIHandleBlock::release_block(block);
1934 }
1935
1936 if (free_handle_block() != NULL) {
1937 JNIHandleBlock* block = free_handle_block();
1938 set_free_handle_block(NULL);
1939 JNIHandleBlock::release_block(block);
1940 }
1941
1942 // These have to be removed while this is still a valid thread.
1943 remove_stack_guard_pages();
1944
1945 if (UseTLAB) {
1946 tlab().make_parsable(true); // retire TLAB, if any
1947 }
1948
1949 #if INCLUDE_ALL_GCS
1950 if (UseG1GC) {
1951 flush_barrier_queues();
1952 }
1953 #endif // INCLUDE_ALL_GCS
1954
1955 Threads::remove(this);
1956 delete this;
1957 }
1958
1959
1960
1961
1962 JavaThread* JavaThread::active() {
1963 Thread* thread = ThreadLocalStorage::thread();
1964 assert(thread != NULL, "just checking");
1965 if (thread->is_Java_thread()) {
1966 return (JavaThread*) thread;
1967 } else {
1968 assert(thread->is_VM_thread(), "this must be a vm thread");
1969 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1970 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1971 assert(ret->is_Java_thread(), "must be a Java thread");
1972 return ret;
1973 }
1974 }
1975
1976 bool JavaThread::is_lock_owned(address adr) const {
1977 if (Thread::is_lock_owned(adr)) return true;
1978
1979 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1980 if (chunk->contains(adr)) return true;
1981 }
1982
1983 return false;
1984 }
1985
1986
1987 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1988 chunk->set_next(monitor_chunks());
1989 set_monitor_chunks(chunk);
1990 }
1991
1992 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1993 guarantee(monitor_chunks() != NULL, "must be non empty");
1994 if (monitor_chunks() == chunk) {
1995 set_monitor_chunks(chunk->next());
1996 } else {
1997 MonitorChunk* prev = monitor_chunks();
1998 while (prev->next() != chunk) prev = prev->next();
1999 prev->set_next(chunk->next());
2000 }
2001 }
2002
2003 // JVM support.
2004
2005 // Note: this function shouldn't block if it's called in
2006 // _thread_in_native_trans state (such as from
2007 // check_special_condition_for_native_trans()).
2008 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2009
2010 if (has_last_Java_frame() && has_async_condition()) {
2011 // If we are at a polling page safepoint (not a poll return)
2012 // then we must defer async exception because live registers
2013 // will be clobbered by the exception path. Poll return is
2014 // ok because the call we a returning from already collides
2015 // with exception handling registers and so there is no issue.
2016 // (The exception handling path kills call result registers but
2017 // this is ok since the exception kills the result anyway).
2018
2019 if (is_at_poll_safepoint()) {
2020 // if the code we are returning to has deoptimized we must defer
2021 // the exception otherwise live registers get clobbered on the
2022 // exception path before deoptimization is able to retrieve them.
2023 //
2024 RegisterMap map(this, false);
2025 frame caller_fr = last_frame().sender(&map);
2026 assert(caller_fr.is_compiled_frame(), "what?");
2027 if (caller_fr.is_deoptimized_frame()) {
2028 if (TraceExceptions) {
2029 ResourceMark rm;
2030 tty->print_cr("deferred async exception at compiled safepoint");
2031 }
2032 return;
2033 }
2034 }
2035 }
2036
2037 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2038 if (condition == _no_async_condition) {
2039 // Conditions have changed since has_special_runtime_exit_condition()
2040 // was called:
2041 // - if we were here only because of an external suspend request,
2042 // then that was taken care of above (or cancelled) so we are done
2043 // - if we were here because of another async request, then it has
2044 // been cleared between the has_special_runtime_exit_condition()
2045 // and now so again we are done
2046 return;
2047 }
2048
2049 // Check for pending async. exception
2050 if (_pending_async_exception != NULL) {
2051 // Only overwrite an already pending exception, if it is not a threadDeath.
2052 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2053
2054 // We cannot call Exceptions::_throw(...) here because we cannot block
2055 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2056
2057 if (TraceExceptions) {
2058 ResourceMark rm;
2059 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2060 if (has_last_Java_frame()) {
2061 frame f = last_frame();
2062 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2063 }
2064 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2065 }
2066 _pending_async_exception = NULL;
2067 clear_has_async_exception();
2068 }
2069 }
2070
2071 if (check_unsafe_error &&
2072 condition == _async_unsafe_access_error && !has_pending_exception()) {
2073 condition = _no_async_condition; // done
2074 switch (thread_state()) {
2075 case _thread_in_vm:
2076 {
2077 JavaThread* THREAD = this;
2078 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2079 }
2080 case _thread_in_native:
2081 {
2082 ThreadInVMfromNative tiv(this);
2083 JavaThread* THREAD = this;
2084 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2085 }
2086 case _thread_in_Java:
2087 {
2088 ThreadInVMfromJava tiv(this);
2089 JavaThread* THREAD = this;
2090 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2091 }
2092 default:
2093 ShouldNotReachHere();
2094 }
2095 }
2096
2097 assert(condition == _no_async_condition || has_pending_exception() ||
2098 (!check_unsafe_error && condition == _async_unsafe_access_error),
2099 "must have handled the async condition, if no exception");
2100 }
2101
2102 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2103 //
2104 // Check for pending external suspend. Internal suspend requests do
2105 // not use handle_special_runtime_exit_condition().
2106 // If JNIEnv proxies are allowed, don't self-suspend if the target
2107 // thread is not the current thread. In older versions of jdbx, jdbx
2108 // threads could call into the VM with another thread's JNIEnv so we
2109 // can be here operating on behalf of a suspended thread (4432884).
2110 bool do_self_suspend = is_external_suspend_with_lock();
2111 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2112 //
2113 // Because thread is external suspended the safepoint code will count
2114 // thread as at a safepoint. This can be odd because we can be here
2115 // as _thread_in_Java which would normally transition to _thread_blocked
2116 // at a safepoint. We would like to mark the thread as _thread_blocked
2117 // before calling java_suspend_self like all other callers of it but
2118 // we must then observe proper safepoint protocol. (We can't leave
2119 // _thread_blocked with a safepoint in progress). However we can be
2120 // here as _thread_in_native_trans so we can't use a normal transition
2121 // constructor/destructor pair because they assert on that type of
2122 // transition. We could do something like:
2123 //
2124 // JavaThreadState state = thread_state();
2125 // set_thread_state(_thread_in_vm);
2126 // {
2127 // ThreadBlockInVM tbivm(this);
2128 // java_suspend_self()
2129 // }
2130 // set_thread_state(_thread_in_vm_trans);
2131 // if (safepoint) block;
2132 // set_thread_state(state);
2133 //
2134 // but that is pretty messy. Instead we just go with the way the
2135 // code has worked before and note that this is the only path to
2136 // java_suspend_self that doesn't put the thread in _thread_blocked
2137 // mode.
2138
2139 frame_anchor()->make_walkable(this);
2140 java_suspend_self();
2141
2142 // We might be here for reasons in addition to the self-suspend request
2143 // so check for other async requests.
2144 }
2145
2146 if (check_asyncs) {
2147 check_and_handle_async_exceptions();
2148 }
2149 }
2150
2151 void JavaThread::send_thread_stop(oop java_throwable) {
2152 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2153 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2154 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2155
2156 // Do not throw asynchronous exceptions against the compiler thread
2157 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2158 if (is_Compiler_thread()) return;
2159
2160 {
2161 // Actually throw the Throwable against the target Thread - however
2162 // only if there is no thread death exception installed already.
2163 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2164 // If the topmost frame is a runtime stub, then we are calling into
2165 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2166 // must deoptimize the caller before continuing, as the compiled exception handler table
2167 // may not be valid
2168 if (has_last_Java_frame()) {
2169 frame f = last_frame();
2170 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2171 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2172 RegisterMap reg_map(this, UseBiasedLocking);
2173 frame compiled_frame = f.sender(®_map);
2174 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2175 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2176 }
2177 }
2178 }
2179
2180 // Set async. pending exception in thread.
2181 set_pending_async_exception(java_throwable);
2182
2183 if (TraceExceptions) {
2184 ResourceMark rm;
2185 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2186 }
2187 // for AbortVMOnException flag
2188 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2189 }
2190 }
2191
2192
2193 // Interrupt thread so it will wake up from a potential wait()
2194 Thread::interrupt(this);
2195 }
2196
2197 // External suspension mechanism.
2198 //
2199 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2200 // to any VM_locks and it is at a transition
2201 // Self-suspension will happen on the transition out of the vm.
2202 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2203 //
2204 // Guarantees on return:
2205 // + Target thread will not execute any new bytecode (that's why we need to
2206 // force a safepoint)
2207 // + Target thread will not enter any new monitors
2208 //
2209 void JavaThread::java_suspend() {
2210 { MutexLocker mu(Threads_lock);
2211 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2212 return;
2213 }
2214 }
2215
2216 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2217 if (!is_external_suspend()) {
2218 // a racing resume has cancelled us; bail out now
2219 return;
2220 }
2221
2222 // suspend is done
2223 uint32_t debug_bits = 0;
2224 // Warning: is_ext_suspend_completed() may temporarily drop the
2225 // SR_lock to allow the thread to reach a stable thread state if
2226 // it is currently in a transient thread state.
2227 if (is_ext_suspend_completed(false /* !called_by_wait */,
2228 SuspendRetryDelay, &debug_bits) ) {
2229 return;
2230 }
2231 }
2232
2233 VM_ForceSafepoint vm_suspend;
2234 VMThread::execute(&vm_suspend);
2235 }
2236
2237 // Part II of external suspension.
2238 // A JavaThread self suspends when it detects a pending external suspend
2239 // request. This is usually on transitions. It is also done in places
2240 // where continuing to the next transition would surprise the caller,
2241 // e.g., monitor entry.
2242 //
2243 // Returns the number of times that the thread self-suspended.
2244 //
2245 // Note: DO NOT call java_suspend_self() when you just want to block current
2246 // thread. java_suspend_self() is the second stage of cooperative
2247 // suspension for external suspend requests and should only be used
2248 // to complete an external suspend request.
2249 //
2250 int JavaThread::java_suspend_self() {
2251 int ret = 0;
2252
2253 // we are in the process of exiting so don't suspend
2254 if (is_exiting()) {
2255 clear_external_suspend();
2256 return ret;
2257 }
2258
2259 assert(_anchor.walkable() ||
2260 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2261 "must have walkable stack");
2262
2263 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2264
2265 assert(!this->is_ext_suspended(),
2266 "a thread trying to self-suspend should not already be suspended");
2267
2268 if (this->is_suspend_equivalent()) {
2269 // If we are self-suspending as a result of the lifting of a
2270 // suspend equivalent condition, then the suspend_equivalent
2271 // flag is not cleared until we set the ext_suspended flag so
2272 // that wait_for_ext_suspend_completion() returns consistent
2273 // results.
2274 this->clear_suspend_equivalent();
2275 }
2276
2277 // A racing resume may have cancelled us before we grabbed SR_lock
2278 // above. Or another external suspend request could be waiting for us
2279 // by the time we return from SR_lock()->wait(). The thread
2280 // that requested the suspension may already be trying to walk our
2281 // stack and if we return now, we can change the stack out from under
2282 // it. This would be a "bad thing (TM)" and cause the stack walker
2283 // to crash. We stay self-suspended until there are no more pending
2284 // external suspend requests.
2285 while (is_external_suspend()) {
2286 ret++;
2287 this->set_ext_suspended();
2288
2289 // _ext_suspended flag is cleared by java_resume()
2290 while (is_ext_suspended()) {
2291 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2292 }
2293 }
2294
2295 return ret;
2296 }
2297
2298 #ifdef ASSERT
2299 // verify the JavaThread has not yet been published in the Threads::list, and
2300 // hence doesn't need protection from concurrent access at this stage
2301 void JavaThread::verify_not_published() {
2302 if (!Threads_lock->owned_by_self()) {
2303 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2304 assert(!Threads::includes(this),
2305 "java thread shouldn't have been published yet!");
2306 }
2307 else {
2308 assert(!Threads::includes(this),
2309 "java thread shouldn't have been published yet!");
2310 }
2311 }
2312 #endif
2313
2314 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2315 // progress or when _suspend_flags is non-zero.
2316 // Current thread needs to self-suspend if there is a suspend request and/or
2317 // block if a safepoint is in progress.
2318 // Async exception ISN'T checked.
2319 // Note only the ThreadInVMfromNative transition can call this function
2320 // directly and when thread state is _thread_in_native_trans
2321 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2322 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2323
2324 JavaThread *curJT = JavaThread::current();
2325 bool do_self_suspend = thread->is_external_suspend();
2326
2327 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2328
2329 // If JNIEnv proxies are allowed, don't self-suspend if the target
2330 // thread is not the current thread. In older versions of jdbx, jdbx
2331 // threads could call into the VM with another thread's JNIEnv so we
2332 // can be here operating on behalf of a suspended thread (4432884).
2333 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2334 JavaThreadState state = thread->thread_state();
2335
2336 // We mark this thread_blocked state as a suspend-equivalent so
2337 // that a caller to is_ext_suspend_completed() won't be confused.
2338 // The suspend-equivalent state is cleared by java_suspend_self().
2339 thread->set_suspend_equivalent();
2340
2341 // If the safepoint code sees the _thread_in_native_trans state, it will
2342 // wait until the thread changes to other thread state. There is no
2343 // guarantee on how soon we can obtain the SR_lock and complete the
2344 // self-suspend request. It would be a bad idea to let safepoint wait for
2345 // too long. Temporarily change the state to _thread_blocked to
2346 // let the VM thread know that this thread is ready for GC. The problem
2347 // of changing thread state is that safepoint could happen just after
2348 // java_suspend_self() returns after being resumed, and VM thread will
2349 // see the _thread_blocked state. We must check for safepoint
2350 // after restoring the state and make sure we won't leave while a safepoint
2351 // is in progress.
2352 thread->set_thread_state(_thread_blocked);
2353 thread->java_suspend_self();
2354 thread->set_thread_state(state);
2355 // Make sure new state is seen by VM thread
2356 if (os::is_MP()) {
2357 if (UseMembar) {
2358 // Force a fence between the write above and read below
2359 OrderAccess::fence();
2360 } else {
2361 // Must use this rather than serialization page in particular on Windows
2362 InterfaceSupport::serialize_memory(thread);
2363 }
2364 }
2365 }
2366
2367 if (SafepointSynchronize::do_call_back()) {
2368 // If we are safepointing, then block the caller which may not be
2369 // the same as the target thread (see above).
2370 SafepointSynchronize::block(curJT);
2371 }
2372
2373 if (thread->is_deopt_suspend()) {
2374 thread->clear_deopt_suspend();
2375 RegisterMap map(thread, false);
2376 frame f = thread->last_frame();
2377 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2378 f = f.sender(&map);
2379 }
2380 if (f.id() == thread->must_deopt_id()) {
2381 thread->clear_must_deopt_id();
2382 f.deoptimize(thread);
2383 } else {
2384 fatal("missed deoptimization!");
2385 }
2386 }
2387 }
2388
2389 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2390 // progress or when _suspend_flags is non-zero.
2391 // Current thread needs to self-suspend if there is a suspend request and/or
2392 // block if a safepoint is in progress.
2393 // Also check for pending async exception (not including unsafe access error).
2394 // Note only the native==>VM/Java barriers can call this function and when
2395 // thread state is _thread_in_native_trans.
2396 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2397 check_safepoint_and_suspend_for_native_trans(thread);
2398
2399 if (thread->has_async_exception()) {
2400 // We are in _thread_in_native_trans state, don't handle unsafe
2401 // access error since that may block.
2402 thread->check_and_handle_async_exceptions(false);
2403 }
2404 }
2405
2406 // This is a variant of the normal
2407 // check_special_condition_for_native_trans with slightly different
2408 // semantics for use by critical native wrappers. It does all the
2409 // normal checks but also performs the transition back into
2410 // thread_in_Java state. This is required so that critical natives
2411 // can potentially block and perform a GC if they are the last thread
2412 // exiting the GC_locker.
2413 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2414 check_special_condition_for_native_trans(thread);
2415
2416 // Finish the transition
2417 thread->set_thread_state(_thread_in_Java);
2418
2419 if (thread->do_critical_native_unlock()) {
2420 ThreadInVMfromJavaNoAsyncException tiv(thread);
2421 GC_locker::unlock_critical(thread);
2422 thread->clear_critical_native_unlock();
2423 }
2424 }
2425
2426 // We need to guarantee the Threads_lock here, since resumes are not
2427 // allowed during safepoint synchronization
2428 // Can only resume from an external suspension
2429 void JavaThread::java_resume() {
2430 assert_locked_or_safepoint(Threads_lock);
2431
2432 // Sanity check: thread is gone, has started exiting or the thread
2433 // was not externally suspended.
2434 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2435 return;
2436 }
2437
2438 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2439
2440 clear_external_suspend();
2441
2442 if (is_ext_suspended()) {
2443 clear_ext_suspended();
2444 SR_lock()->notify_all();
2445 }
2446 }
2447
2448 void JavaThread::create_stack_guard_pages() {
2449 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2450 address low_addr = stack_base() - stack_size();
2451 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2452
2453 int allocate = os::allocate_stack_guard_pages();
2454 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2455
2456 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2457 warning("Attempt to allocate stack guard pages failed.");
2458 return;
2459 }
2460
2461 if (os::guard_memory((char *) low_addr, len)) {
2462 _stack_guard_state = stack_guard_enabled;
2463 } else {
2464 warning("Attempt to protect stack guard pages failed.");
2465 if (os::uncommit_memory((char *) low_addr, len)) {
2466 warning("Attempt to deallocate stack guard pages failed.");
2467 }
2468 }
2469 }
2470
2471 void JavaThread::remove_stack_guard_pages() {
2472 assert(Thread::current() == this, "from different thread");
2473 if (_stack_guard_state == stack_guard_unused) return;
2474 address low_addr = stack_base() - stack_size();
2475 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2476
2477 if (os::allocate_stack_guard_pages()) {
2478 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2479 _stack_guard_state = stack_guard_unused;
2480 } else {
2481 warning("Attempt to deallocate stack guard pages failed.");
2482 }
2483 } else {
2484 if (_stack_guard_state == stack_guard_unused) return;
2485 if (os::unguard_memory((char *) low_addr, len)) {
2486 _stack_guard_state = stack_guard_unused;
2487 } else {
2488 warning("Attempt to unprotect stack guard pages failed.");
2489 }
2490 }
2491 }
2492
2493 void JavaThread::enable_stack_yellow_zone() {
2494 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2495 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2496
2497 // The base notation is from the stacks point of view, growing downward.
2498 // We need to adjust it to work correctly with guard_memory()
2499 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2500
2501 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2502 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2503
2504 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2505 _stack_guard_state = stack_guard_enabled;
2506 } else {
2507 warning("Attempt to guard stack yellow zone failed.");
2508 }
2509 enable_register_stack_guard();
2510 }
2511
2512 void JavaThread::disable_stack_yellow_zone() {
2513 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2514 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2515
2516 // Simply return if called for a thread that does not use guard pages.
2517 if (_stack_guard_state == stack_guard_unused) return;
2518
2519 // The base notation is from the stacks point of view, growing downward.
2520 // We need to adjust it to work correctly with guard_memory()
2521 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2522
2523 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2524 _stack_guard_state = stack_guard_yellow_disabled;
2525 } else {
2526 warning("Attempt to unguard stack yellow zone failed.");
2527 }
2528 disable_register_stack_guard();
2529 }
2530
2531 void JavaThread::enable_stack_red_zone() {
2532 // The base notation is from the stacks point of view, growing downward.
2533 // We need to adjust it to work correctly with guard_memory()
2534 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2535 address base = stack_red_zone_base() - stack_red_zone_size();
2536
2537 guarantee(base < stack_base(), "Error calculating stack red zone");
2538 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2539
2540 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2541 warning("Attempt to guard stack red zone failed.");
2542 }
2543 }
2544
2545 void JavaThread::disable_stack_red_zone() {
2546 // The base notation is from the stacks point of view, growing downward.
2547 // We need to adjust it to work correctly with guard_memory()
2548 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2549 address base = stack_red_zone_base() - stack_red_zone_size();
2550 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2551 warning("Attempt to unguard stack red zone failed.");
2552 }
2553 }
2554
2555 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2556 // ignore is there is no stack
2557 if (!has_last_Java_frame()) return;
2558 // traverse the stack frames. Starts from top frame.
2559 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2560 frame* fr = fst.current();
2561 f(fr, fst.register_map());
2562 }
2563 }
2564
2565
2566 #ifndef PRODUCT
2567 // Deoptimization
2568 // Function for testing deoptimization
2569 void JavaThread::deoptimize() {
2570 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2571 StackFrameStream fst(this, UseBiasedLocking);
2572 bool deopt = false; // Dump stack only if a deopt actually happens.
2573 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2574 // Iterate over all frames in the thread and deoptimize
2575 for (; !fst.is_done(); fst.next()) {
2576 if (fst.current()->can_be_deoptimized()) {
2577
2578 if (only_at) {
2579 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2580 // consists of comma or carriage return separated numbers so
2581 // search for the current bci in that string.
2582 address pc = fst.current()->pc();
2583 nmethod* nm = (nmethod*) fst.current()->cb();
2584 ScopeDesc* sd = nm->scope_desc_at( pc);
2585 char buffer[8];
2586 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2587 size_t len = strlen(buffer);
2588 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2589 while (found != NULL) {
2590 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2591 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2592 // Check that the bci found is bracketed by terminators.
2593 break;
2594 }
2595 found = strstr(found + 1, buffer);
2596 }
2597 if (!found) {
2598 continue;
2599 }
2600 }
2601
2602 if (DebugDeoptimization && !deopt) {
2603 deopt = true; // One-time only print before deopt
2604 tty->print_cr("[BEFORE Deoptimization]");
2605 trace_frames();
2606 trace_stack();
2607 }
2608 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2609 }
2610 }
2611
2612 if (DebugDeoptimization && deopt) {
2613 tty->print_cr("[AFTER Deoptimization]");
2614 trace_frames();
2615 }
2616 }
2617
2618
2619 // Make zombies
2620 void JavaThread::make_zombies() {
2621 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2622 if (fst.current()->can_be_deoptimized()) {
2623 // it is a Java nmethod
2624 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2625 nm->make_not_entrant();
2626 }
2627 }
2628 }
2629 #endif // PRODUCT
2630
2631
2632 void JavaThread::deoptimized_wrt_marked_nmethods() {
2633 if (!has_last_Java_frame()) return;
2634 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2635 StackFrameStream fst(this, UseBiasedLocking);
2636 for (; !fst.is_done(); fst.next()) {
2637 if (fst.current()->should_be_deoptimized()) {
2638 if (LogCompilation && xtty != NULL) {
2639 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2640 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2641 this->name(), nm != NULL ? nm->compile_id() : -1);
2642 }
2643
2644 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2645 }
2646 }
2647 }
2648
2649
2650 // GC support
2651 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2652
2653 void JavaThread::gc_epilogue() {
2654 frames_do(frame_gc_epilogue);
2655 }
2656
2657
2658 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2659
2660 void JavaThread::gc_prologue() {
2661 frames_do(frame_gc_prologue);
2662 }
2663
2664 // If the caller is a NamedThread, then remember, in the current scope,
2665 // the given JavaThread in its _processed_thread field.
2666 class RememberProcessedThread: public StackObj {
2667 NamedThread* _cur_thr;
2668 public:
2669 RememberProcessedThread(JavaThread* jthr) {
2670 Thread* thread = Thread::current();
2671 if (thread->is_Named_thread()) {
2672 _cur_thr = (NamedThread *)thread;
2673 _cur_thr->set_processed_thread(jthr);
2674 } else {
2675 _cur_thr = NULL;
2676 }
2677 }
2678
2679 ~RememberProcessedThread() {
2680 if (_cur_thr) {
2681 _cur_thr->set_processed_thread(NULL);
2682 }
2683 }
2684 };
2685
2686 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2687 // Verify that the deferred card marks have been flushed.
2688 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2689
2690 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2691 // since there may be more than one thread using each ThreadProfiler.
2692
2693 // Traverse the GCHandles
2694 Thread::oops_do(f, cld_f, cf);
2695
2696 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2697 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2698
2699 if (has_last_Java_frame()) {
2700 // Record JavaThread to GC thread
2701 RememberProcessedThread rpt(this);
2702
2703 // Traverse the privileged stack
2704 if (_privileged_stack_top != NULL) {
2705 _privileged_stack_top->oops_do(f);
2706 }
2707
2708 // traverse the registered growable array
2709 if (_array_for_gc != NULL) {
2710 for (int index = 0; index < _array_for_gc->length(); index++) {
2711 f->do_oop(_array_for_gc->adr_at(index));
2712 }
2713 }
2714
2715 // Traverse the monitor chunks
2716 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2717 chunk->oops_do(f);
2718 }
2719
2720 // Traverse the execution stack
2721 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2722 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2723 }
2724 }
2725
2726 // callee_target is never live across a gc point so NULL it here should
2727 // it still contain a methdOop.
2728
2729 set_callee_target(NULL);
2730
2731 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2732 // If we have deferred set_locals there might be oops waiting to be
2733 // written
2734 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2735 if (list != NULL) {
2736 for (int i = 0; i < list->length(); i++) {
2737 list->at(i)->oops_do(f);
2738 }
2739 }
2740
2741 // Traverse instance variables at the end since the GC may be moving things
2742 // around using this function
2743 f->do_oop((oop*) &_threadObj);
2744 f->do_oop((oop*) &_vm_result);
2745 f->do_oop((oop*) &_exception_oop);
2746 f->do_oop((oop*) &_pending_async_exception);
2747
2748 if (jvmti_thread_state() != NULL) {
2749 jvmti_thread_state()->oops_do(f);
2750 }
2751 }
2752
2753 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2754 Thread::nmethods_do(cf); // (super method is a no-op)
2755
2756 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2757 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2758
2759 if (has_last_Java_frame()) {
2760 // Traverse the execution stack
2761 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2762 fst.current()->nmethods_do(cf);
2763 }
2764 }
2765 }
2766
2767 void JavaThread::metadata_do(void f(Metadata*)) {
2768 Thread::metadata_do(f);
2769 if (has_last_Java_frame()) {
2770 // Traverse the execution stack to call f() on the methods in the stack
2771 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2772 fst.current()->metadata_do(f);
2773 }
2774 } else if (is_Compiler_thread()) {
2775 // need to walk ciMetadata in current compile tasks to keep alive.
2776 CompilerThread* ct = (CompilerThread*)this;
2777 if (ct->env() != NULL) {
2778 ct->env()->metadata_do(f);
2779 }
2780 }
2781 }
2782
2783 // Printing
2784 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2785 switch (_thread_state) {
2786 case _thread_uninitialized: return "_thread_uninitialized";
2787 case _thread_new: return "_thread_new";
2788 case _thread_new_trans: return "_thread_new_trans";
2789 case _thread_in_native: return "_thread_in_native";
2790 case _thread_in_native_trans: return "_thread_in_native_trans";
2791 case _thread_in_vm: return "_thread_in_vm";
2792 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2793 case _thread_in_Java: return "_thread_in_Java";
2794 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2795 case _thread_blocked: return "_thread_blocked";
2796 case _thread_blocked_trans: return "_thread_blocked_trans";
2797 default: return "unknown thread state";
2798 }
2799 }
2800
2801 #ifndef PRODUCT
2802 void JavaThread::print_thread_state_on(outputStream *st) const {
2803 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2804 };
2805 void JavaThread::print_thread_state() const {
2806 print_thread_state_on(tty);
2807 };
2808 #endif // PRODUCT
2809
2810 // Called by Threads::print() for VM_PrintThreads operation
2811 void JavaThread::print_on(outputStream *st) const {
2812 st->print("\"%s\" ", get_thread_name());
2813 oop thread_oop = threadObj();
2814 if (thread_oop != NULL) {
2815 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2816 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2817 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2818 }
2819 Thread::print_on(st);
2820 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2821 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2822 if (thread_oop != NULL) {
2823 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2824 }
2825 #ifndef PRODUCT
2826 print_thread_state_on(st);
2827 _safepoint_state->print_on(st);
2828 #endif // PRODUCT
2829 }
2830
2831 // Called by fatal error handler. The difference between this and
2832 // JavaThread::print() is that we can't grab lock or allocate memory.
2833 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2834 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2835 oop thread_obj = threadObj();
2836 if (thread_obj != NULL) {
2837 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2838 }
2839 st->print(" [");
2840 st->print("%s", _get_thread_state_name(_thread_state));
2841 if (osthread()) {
2842 st->print(", id=%d", osthread()->thread_id());
2843 }
2844 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2845 _stack_base - _stack_size, _stack_base);
2846 st->print("]");
2847 return;
2848 }
2849
2850 // Verification
2851
2852 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2853
2854 void JavaThread::verify() {
2855 // Verify oops in the thread.
2856 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2857
2858 // Verify the stack frames.
2859 frames_do(frame_verify);
2860 }
2861
2862 // CR 6300358 (sub-CR 2137150)
2863 // Most callers of this method assume that it can't return NULL but a
2864 // thread may not have a name whilst it is in the process of attaching to
2865 // the VM - see CR 6412693, and there are places where a JavaThread can be
2866 // seen prior to having it's threadObj set (eg JNI attaching threads and
2867 // if vm exit occurs during initialization). These cases can all be accounted
2868 // for such that this method never returns NULL.
2869 const char* JavaThread::get_thread_name() const {
2870 #ifdef ASSERT
2871 // early safepoints can hit while current thread does not yet have TLS
2872 if (!SafepointSynchronize::is_at_safepoint()) {
2873 Thread *cur = Thread::current();
2874 if (!(cur->is_Java_thread() && cur == this)) {
2875 // Current JavaThreads are allowed to get their own name without
2876 // the Threads_lock.
2877 assert_locked_or_safepoint(Threads_lock);
2878 }
2879 }
2880 #endif // ASSERT
2881 return get_thread_name_string();
2882 }
2883
2884 // Returns a non-NULL representation of this thread's name, or a suitable
2885 // descriptive string if there is no set name
2886 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2887 const char* name_str;
2888 oop thread_obj = threadObj();
2889 if (thread_obj != NULL) {
2890 typeArrayOop name = java_lang_Thread::name(thread_obj);
2891 if (name != NULL) {
2892 if (buf == NULL) {
2893 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2894 }
2895 else {
2896 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2897 }
2898 }
2899 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2900 name_str = "<no-name - thread is attaching>";
2901 }
2902 else {
2903 name_str = Thread::name();
2904 }
2905 }
2906 else {
2907 name_str = Thread::name();
2908 }
2909 assert(name_str != NULL, "unexpected NULL thread name");
2910 return name_str;
2911 }
2912
2913
2914 const char* JavaThread::get_threadgroup_name() const {
2915 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2916 oop thread_obj = threadObj();
2917 if (thread_obj != NULL) {
2918 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2919 if (thread_group != NULL) {
2920 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2921 // ThreadGroup.name can be null
2922 if (name != NULL) {
2923 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2924 return str;
2925 }
2926 }
2927 }
2928 return NULL;
2929 }
2930
2931 const char* JavaThread::get_parent_name() const {
2932 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2933 oop thread_obj = threadObj();
2934 if (thread_obj != NULL) {
2935 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2936 if (thread_group != NULL) {
2937 oop parent = java_lang_ThreadGroup::parent(thread_group);
2938 if (parent != NULL) {
2939 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2940 // ThreadGroup.name can be null
2941 if (name != NULL) {
2942 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2943 return str;
2944 }
2945 }
2946 }
2947 }
2948 return NULL;
2949 }
2950
2951 ThreadPriority JavaThread::java_priority() const {
2952 oop thr_oop = threadObj();
2953 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2954 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2955 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2956 return priority;
2957 }
2958
2959 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2960
2961 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2962 // Link Java Thread object <-> C++ Thread
2963
2964 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2965 // and put it into a new Handle. The Handle "thread_oop" can then
2966 // be used to pass the C++ thread object to other methods.
2967
2968 // Set the Java level thread object (jthread) field of the
2969 // new thread (a JavaThread *) to C++ thread object using the
2970 // "thread_oop" handle.
2971
2972 // Set the thread field (a JavaThread *) of the
2973 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2974
2975 Handle thread_oop(Thread::current(),
2976 JNIHandles::resolve_non_null(jni_thread));
2977 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2978 "must be initialized");
2979 set_threadObj(thread_oop());
2980 java_lang_Thread::set_thread(thread_oop(), this);
2981
2982 if (prio == NoPriority) {
2983 prio = java_lang_Thread::priority(thread_oop());
2984 assert(prio != NoPriority, "A valid priority should be present");
2985 }
2986
2987 // Push the Java priority down to the native thread; needs Threads_lock
2988 Thread::set_priority(this, prio);
2989
2990 // Add the new thread to the Threads list and set it in motion.
2991 // We must have threads lock in order to call Threads::add.
2992 // It is crucial that we do not block before the thread is
2993 // added to the Threads list for if a GC happens, then the java_thread oop
2994 // will not be visited by GC.
2995 Threads::add(this);
2996 }
2997
2998 oop JavaThread::current_park_blocker() {
2999 // Support for JSR-166 locks
3000 oop thread_oop = threadObj();
3001 if (thread_oop != NULL &&
3002 JDK_Version::current().supports_thread_park_blocker()) {
3003 return java_lang_Thread::park_blocker(thread_oop);
3004 }
3005 return NULL;
3006 }
3007
3008
3009 void JavaThread::print_stack_on(outputStream* st) {
3010 if (!has_last_Java_frame()) return;
3011 ResourceMark rm;
3012 HandleMark hm;
3013
3014 RegisterMap reg_map(this);
3015 vframe* start_vf = last_java_vframe(®_map);
3016 int count = 0;
3017 for (vframe* f = start_vf; f; f = f->sender()) {
3018 if (f->is_java_frame()) {
3019 javaVFrame* jvf = javaVFrame::cast(f);
3020 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3021
3022 // Print out lock information
3023 if (JavaMonitorsInStackTrace) {
3024 jvf->print_lock_info_on(st, count);
3025 }
3026 } else {
3027 // Ignore non-Java frames
3028 }
3029
3030 // Bail-out case for too deep stacks
3031 count++;
3032 if (MaxJavaStackTraceDepth == count) return;
3033 }
3034 }
3035
3036
3037 // JVMTI PopFrame support
3038 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3039 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3040 if (in_bytes(size_in_bytes) != 0) {
3041 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3042 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3043 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3044 }
3045 }
3046
3047 void* JavaThread::popframe_preserved_args() {
3048 return _popframe_preserved_args;
3049 }
3050
3051 ByteSize JavaThread::popframe_preserved_args_size() {
3052 return in_ByteSize(_popframe_preserved_args_size);
3053 }
3054
3055 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3056 int sz = in_bytes(popframe_preserved_args_size());
3057 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3058 return in_WordSize(sz / wordSize);
3059 }
3060
3061 void JavaThread::popframe_free_preserved_args() {
3062 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3063 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3064 _popframe_preserved_args = NULL;
3065 _popframe_preserved_args_size = 0;
3066 }
3067
3068 #ifndef PRODUCT
3069
3070 void JavaThread::trace_frames() {
3071 tty->print_cr("[Describe stack]");
3072 int frame_no = 1;
3073 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3074 tty->print(" %d. ", frame_no++);
3075 fst.current()->print_value_on(tty, this);
3076 tty->cr();
3077 }
3078 }
3079
3080 class PrintAndVerifyOopClosure: public OopClosure {
3081 protected:
3082 template <class T> inline void do_oop_work(T* p) {
3083 oop obj = oopDesc::load_decode_heap_oop(p);
3084 if (obj == NULL) return;
3085 tty->print(INTPTR_FORMAT ": ", p);
3086 if (obj->is_oop_or_null()) {
3087 if (obj->is_objArray()) {
3088 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3089 } else {
3090 obj->print();
3091 }
3092 } else {
3093 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3094 }
3095 tty->cr();
3096 }
3097 public:
3098 virtual void do_oop(oop* p) { do_oop_work(p); }
3099 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3100 };
3101
3102
3103 static void oops_print(frame* f, const RegisterMap *map) {
3104 PrintAndVerifyOopClosure print;
3105 f->print_value();
3106 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3107 }
3108
3109 // Print our all the locations that contain oops and whether they are
3110 // valid or not. This useful when trying to find the oldest frame
3111 // where an oop has gone bad since the frame walk is from youngest to
3112 // oldest.
3113 void JavaThread::trace_oops() {
3114 tty->print_cr("[Trace oops]");
3115 frames_do(oops_print);
3116 }
3117
3118
3119 #ifdef ASSERT
3120 // Print or validate the layout of stack frames
3121 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3122 ResourceMark rm;
3123 PRESERVE_EXCEPTION_MARK;
3124 FrameValues values;
3125 int frame_no = 0;
3126 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3127 fst.current()->describe(values, ++frame_no);
3128 if (depth == frame_no) break;
3129 }
3130 if (validate_only) {
3131 values.validate();
3132 } else {
3133 tty->print_cr("[Describe stack layout]");
3134 values.print(this);
3135 }
3136 }
3137 #endif
3138
3139 void JavaThread::trace_stack_from(vframe* start_vf) {
3140 ResourceMark rm;
3141 int vframe_no = 1;
3142 for (vframe* f = start_vf; f; f = f->sender()) {
3143 if (f->is_java_frame()) {
3144 javaVFrame::cast(f)->print_activation(vframe_no++);
3145 } else {
3146 f->print();
3147 }
3148 if (vframe_no > StackPrintLimit) {
3149 tty->print_cr("...<more frames>...");
3150 return;
3151 }
3152 }
3153 }
3154
3155
3156 void JavaThread::trace_stack() {
3157 if (!has_last_Java_frame()) return;
3158 ResourceMark rm;
3159 HandleMark hm;
3160 RegisterMap reg_map(this);
3161 trace_stack_from(last_java_vframe(®_map));
3162 }
3163
3164
3165 #endif // PRODUCT
3166
3167
3168 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3169 assert(reg_map != NULL, "a map must be given");
3170 frame f = last_frame();
3171 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3172 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3173 }
3174 return NULL;
3175 }
3176
3177
3178 Klass* JavaThread::security_get_caller_class(int depth) {
3179 vframeStream vfst(this);
3180 vfst.security_get_caller_frame(depth);
3181 if (!vfst.at_end()) {
3182 return vfst.method()->method_holder();
3183 }
3184 return NULL;
3185 }
3186
3187 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3188 assert(thread->is_Compiler_thread(), "must be compiler thread");
3189 CompileBroker::compiler_thread_loop();
3190 }
3191
3192 // Create a CompilerThread
3193 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3194 : JavaThread(&compiler_thread_entry) {
3195 _env = NULL;
3196 _log = NULL;
3197 _task = NULL;
3198 _queue = queue;
3199 _counters = counters;
3200 _buffer_blob = NULL;
3201 _scanned_nmethod = NULL;
3202 _compiler = NULL;
3203
3204 #ifndef PRODUCT
3205 _ideal_graph_printer = NULL;
3206 #endif
3207 }
3208
3209 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3210 JavaThread::oops_do(f, cld_f, cf);
3211 if (_scanned_nmethod != NULL && cf != NULL) {
3212 // Safepoints can occur when the sweeper is scanning an nmethod so
3213 // process it here to make sure it isn't unloaded in the middle of
3214 // a scan.
3215 cf->do_code_blob(_scanned_nmethod);
3216 }
3217 }
3218
3219
3220 // ======= Threads ========
3221
3222 // The Threads class links together all active threads, and provides
3223 // operations over all threads. It is protected by its own Mutex
3224 // lock, which is also used in other contexts to protect thread
3225 // operations from having the thread being operated on from exiting
3226 // and going away unexpectedly (e.g., safepoint synchronization)
3227
3228 JavaThread* Threads::_thread_list = NULL;
3229 int Threads::_number_of_threads = 0;
3230 int Threads::_number_of_non_daemon_threads = 0;
3231 int Threads::_return_code = 0;
3232 size_t JavaThread::_stack_size_at_create = 0;
3233 #ifdef ASSERT
3234 bool Threads::_vm_complete = false;
3235 #endif
3236
3237 // All JavaThreads
3238 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3239
3240 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3241 void Threads::threads_do(ThreadClosure* tc) {
3242 assert_locked_or_safepoint(Threads_lock);
3243 // ALL_JAVA_THREADS iterates through all JavaThreads
3244 ALL_JAVA_THREADS(p) {
3245 tc->do_thread(p);
3246 }
3247 // Someday we could have a table or list of all non-JavaThreads.
3248 // For now, just manually iterate through them.
3249 tc->do_thread(VMThread::vm_thread());
3250 Universe::heap()->gc_threads_do(tc);
3251 WatcherThread *wt = WatcherThread::watcher_thread();
3252 // Strictly speaking, the following NULL check isn't sufficient to make sure
3253 // the data for WatcherThread is still valid upon being examined. However,
3254 // considering that WatchThread terminates when the VM is on the way to
3255 // exit at safepoint, the chance of the above is extremely small. The right
3256 // way to prevent termination of WatcherThread would be to acquire
3257 // Terminator_lock, but we can't do that without violating the lock rank
3258 // checking in some cases.
3259 if (wt != NULL)
3260 tc->do_thread(wt);
3261
3262 // If CompilerThreads ever become non-JavaThreads, add them here
3263 }
3264
3265
3266 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3267 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3268
3269 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3270 create_vm_init_libraries();
3271 }
3272
3273 initialize_class(vmSymbols::java_lang_String(), CHECK);
3274
3275 // Initialize java_lang.System (needed before creating the thread)
3276 initialize_class(vmSymbols::java_lang_System(), CHECK);
3277 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3278 Handle thread_group = create_initial_thread_group(CHECK);
3279 Universe::set_main_thread_group(thread_group());
3280 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3281 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3282 main_thread->set_threadObj(thread_object);
3283 // Set thread status to running since main thread has
3284 // been started and running.
3285 java_lang_Thread::set_thread_status(thread_object,
3286 java_lang_Thread::RUNNABLE);
3287
3288 // The VM creates & returns objects of this class. Make sure it's initialized.
3289 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3290
3291 // The VM preresolves methods to these classes. Make sure that they get initialized
3292 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3293 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3294 call_initializeSystemClass(CHECK);
3295
3296 // get the Java runtime name after java.lang.System is initialized
3297 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3298 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3299
3300 // an instance of OutOfMemory exception has been allocated earlier
3301 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3302 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3303 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3304 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3305 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3306 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3307 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3308 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3309 }
3310
3311 void Threads::initialize_jsr292_core_classes(TRAPS) {
3312 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3313 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3314 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3315 }
3316
3317 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3318
3319 extern void JDK_Version_init();
3320
3321 // Check version
3322 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3323
3324 // Initialize the output stream module
3325 ostream_init();
3326
3327 // Process java launcher properties.
3328 Arguments::process_sun_java_launcher_properties(args);
3329
3330 // Initialize the os module before using TLS
3331 os::init();
3332
3333 // Initialize system properties.
3334 Arguments::init_system_properties();
3335
3336 // So that JDK version can be used as a discriminator when parsing arguments
3337 JDK_Version_init();
3338
3339 // Update/Initialize System properties after JDK version number is known
3340 Arguments::init_version_specific_system_properties();
3341
3342 // Parse arguments
3343 jint parse_result = Arguments::parse(args);
3344 if (parse_result != JNI_OK) return parse_result;
3345
3346 os::init_before_ergo();
3347
3348 jint ergo_result = Arguments::apply_ergo();
3349 if (ergo_result != JNI_OK) return ergo_result;
3350
3351 if (PauseAtStartup) {
3352 os::pause();
3353 }
3354
3355 HOTSPOT_VM_INIT_BEGIN();
3356
3357 // Record VM creation timing statistics
3358 TraceVmCreationTime create_vm_timer;
3359 create_vm_timer.start();
3360
3361 // Timing (must come after argument parsing)
3362 TraceTime timer("Create VM", TraceStartupTime);
3363
3364 // Initialize the os module after parsing the args
3365 jint os_init_2_result = os::init_2();
3366 if (os_init_2_result != JNI_OK) return os_init_2_result;
3367
3368 jint adjust_after_os_result = Arguments::adjust_after_os();
3369 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3370
3371 // initialize TLS
3372 ThreadLocalStorage::init();
3373
3374 // Bootstrap native memory tracking, so it can start recording memory
3375 // activities before worker thread is started. This is the first phase
3376 // of bootstrapping, VM is currently running in single-thread mode.
3377 MemTracker::bootstrap_single_thread();
3378
3379 // Initialize output stream logging
3380 ostream_init_log();
3381
3382 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3383 // Must be before create_vm_init_agents()
3384 if (Arguments::init_libraries_at_startup()) {
3385 convert_vm_init_libraries_to_agents();
3386 }
3387
3388 // Launch -agentlib/-agentpath and converted -Xrun agents
3389 if (Arguments::init_agents_at_startup()) {
3390 create_vm_init_agents();
3391 }
3392
3393 // Initialize Threads state
3394 _thread_list = NULL;
3395 _number_of_threads = 0;
3396 _number_of_non_daemon_threads = 0;
3397
3398 // Initialize global data structures and create system classes in heap
3399 vm_init_globals();
3400
3401 // Attach the main thread to this os thread
3402 JavaThread* main_thread = new JavaThread();
3403 main_thread->set_thread_state(_thread_in_vm);
3404 // must do this before set_active_handles and initialize_thread_local_storage
3405 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3406 // change the stack size recorded here to one based on the java thread
3407 // stacksize. This adjusted size is what is used to figure the placement
3408 // of the guard pages.
3409 main_thread->record_stack_base_and_size();
3410 main_thread->initialize_thread_local_storage();
3411
3412 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3413
3414 if (!main_thread->set_as_starting_thread()) {
3415 vm_shutdown_during_initialization(
3416 "Failed necessary internal allocation. Out of swap space");
3417 delete main_thread;
3418 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3419 return JNI_ENOMEM;
3420 }
3421
3422 // Enable guard page *after* os::create_main_thread(), otherwise it would
3423 // crash Linux VM, see notes in os_linux.cpp.
3424 main_thread->create_stack_guard_pages();
3425
3426 // Initialize Java-Level synchronization subsystem
3427 ObjectMonitor::Initialize();
3428
3429 // Second phase of bootstrapping, VM is about entering multi-thread mode
3430 MemTracker::bootstrap_multi_thread();
3431
3432 // Initialize global modules
3433 jint status = init_globals();
3434 if (status != JNI_OK) {
3435 delete main_thread;
3436 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3437 return status;
3438 }
3439
3440 // Should be done after the heap is fully created
3441 main_thread->cache_global_variables();
3442
3443 HandleMark hm;
3444
3445 { MutexLocker mu(Threads_lock);
3446 Threads::add(main_thread);
3447 }
3448
3449 // Any JVMTI raw monitors entered in onload will transition into
3450 // real raw monitor. VM is setup enough here for raw monitor enter.
3451 JvmtiExport::transition_pending_onload_raw_monitors();
3452
3453 // Fully start NMT
3454 MemTracker::start();
3455
3456 // Create the VMThread
3457 { TraceTime timer("Start VMThread", TraceStartupTime);
3458 VMThread::create();
3459 Thread* vmthread = VMThread::vm_thread();
3460
3461 if (!os::create_thread(vmthread, os::vm_thread))
3462 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3463
3464 // Wait for the VM thread to become ready, and VMThread::run to initialize
3465 // Monitors can have spurious returns, must always check another state flag
3466 {
3467 MutexLocker ml(Notify_lock);
3468 os::start_thread(vmthread);
3469 while (vmthread->active_handles() == NULL) {
3470 Notify_lock->wait();
3471 }
3472 }
3473 }
3474
3475 assert(Universe::is_fully_initialized(), "not initialized");
3476 if (VerifyDuringStartup) {
3477 // Make sure we're starting with a clean slate.
3478 VM_Verify verify_op;
3479 VMThread::execute(&verify_op);
3480 }
3481
3482 Thread* THREAD = Thread::current();
3483
3484 // At this point, the Universe is initialized, but we have not executed
3485 // any byte code. Now is a good time (the only time) to dump out the
3486 // internal state of the JVM for sharing.
3487 if (DumpSharedSpaces) {
3488 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3489 ShouldNotReachHere();
3490 }
3491
3492 // Always call even when there are not JVMTI environments yet, since environments
3493 // may be attached late and JVMTI must track phases of VM execution
3494 JvmtiExport::enter_start_phase();
3495
3496 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3497 JvmtiExport::post_vm_start();
3498
3499 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3500
3501 // We need this for ClassDataSharing - the initial vm.info property is set
3502 // with the default value of CDS "sharing" which may be reset through
3503 // command line options.
3504 reset_vm_info_property(CHECK_JNI_ERR);
3505
3506 quicken_jni_functions();
3507
3508 // Must be run after init_ft which initializes ft_enabled
3509 if (TRACE_INITIALIZE() != JNI_OK) {
3510 vm_exit_during_initialization("Failed to initialize tracing backend");
3511 }
3512
3513 // Set flag that basic initialization has completed. Used by exceptions and various
3514 // debug stuff, that does not work until all basic classes have been initialized.
3515 set_init_completed();
3516
3517 Metaspace::post_initialize();
3518
3519 HOTSPOT_VM_INIT_END();
3520
3521 // record VM initialization completion time
3522 #if INCLUDE_MANAGEMENT
3523 Management::record_vm_init_completed();
3524 #endif // INCLUDE_MANAGEMENT
3525
3526 // Compute system loader. Note that this has to occur after set_init_completed, since
3527 // valid exceptions may be thrown in the process.
3528 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3529 // set_init_completed has just been called, causing exceptions not to be shortcut
3530 // anymore. We call vm_exit_during_initialization directly instead.
3531 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3532
3533 #if INCLUDE_ALL_GCS
3534 // Support for ConcurrentMarkSweep. This should be cleaned up
3535 // and better encapsulated. The ugly nested if test would go away
3536 // once things are properly refactored. XXX YSR
3537 if (UseConcMarkSweepGC || UseG1GC) {
3538 if (UseConcMarkSweepGC) {
3539 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3540 } else {
3541 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3542 }
3543 }
3544 #endif // INCLUDE_ALL_GCS
3545
3546 // Always call even when there are not JVMTI environments yet, since environments
3547 // may be attached late and JVMTI must track phases of VM execution
3548 JvmtiExport::enter_live_phase();
3549
3550 // Signal Dispatcher needs to be started before VMInit event is posted
3551 os::signal_init();
3552
3553 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3554 if (!DisableAttachMechanism) {
3555 AttachListener::vm_start();
3556 if (StartAttachListener || AttachListener::init_at_startup()) {
3557 AttachListener::init();
3558 }
3559 }
3560
3561 // Launch -Xrun agents
3562 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3563 // back-end can launch with -Xdebug -Xrunjdwp.
3564 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3565 create_vm_init_libraries();
3566 }
3567
3568 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3569 JvmtiExport::post_vm_initialized();
3570
3571 if (TRACE_START() != JNI_OK) {
3572 vm_exit_during_initialization("Failed to start tracing backend.");
3573 }
3574
3575 if (CleanChunkPoolAsync) {
3576 Chunk::start_chunk_pool_cleaner_task();
3577 }
3578
3579 // initialize compiler(s)
3580 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3581 CompileBroker::compilation_init();
3582 #endif
3583
3584 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3585 // It is done after compilers are initialized, because otherwise compilations of
3586 // signature polymorphic MH intrinsics can be missed
3587 // (see SystemDictionary::find_method_handle_intrinsic).
3588 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3589
3590 #if INCLUDE_MANAGEMENT
3591 Management::initialize(THREAD);
3592
3593 if (HAS_PENDING_EXCEPTION) {
3594 // management agent fails to start possibly due to
3595 // configuration problem and is responsible for printing
3596 // stack trace if appropriate. Simply exit VM.
3597 vm_exit(1);
3598 }
3599 #endif // INCLUDE_MANAGEMENT
3600
3601 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3602 if (MemProfiling) MemProfiler::engage();
3603 StatSampler::engage();
3604 if (CheckJNICalls) JniPeriodicChecker::engage();
3605
3606 BiasedLocking::init();
3607
3608 #if INCLUDE_RTM_OPT
3609 RTMLockingCounters::init();
3610 #endif
3611
3612 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3613 call_postVMInitHook(THREAD);
3614 // The Java side of PostVMInitHook.run must deal with all
3615 // exceptions and provide means of diagnosis.
3616 if (HAS_PENDING_EXCEPTION) {
3617 CLEAR_PENDING_EXCEPTION;
3618 }
3619 }
3620
3621 {
3622 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3623 // Make sure the watcher thread can be started by WatcherThread::start()
3624 // or by dynamic enrollment.
3625 WatcherThread::make_startable();
3626 // Start up the WatcherThread if there are any periodic tasks
3627 // NOTE: All PeriodicTasks should be registered by now. If they
3628 // aren't, late joiners might appear to start slowly (we might
3629 // take a while to process their first tick).
3630 if (PeriodicTask::num_tasks() > 0) {
3631 WatcherThread::start();
3632 }
3633 }
3634
3635 // Give os specific code one last chance to start
3636 os::init_3();
3637
3638 create_vm_timer.end();
3639 #ifdef ASSERT
3640 _vm_complete = true;
3641 #endif
3642 return JNI_OK;
3643 }
3644
3645 // type for the Agent_OnLoad and JVM_OnLoad entry points
3646 extern "C" {
3647 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3648 }
3649 // Find a command line agent library and return its entry point for
3650 // -agentlib: -agentpath: -Xrun
3651 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3652 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3653 OnLoadEntry_t on_load_entry = NULL;
3654 void *library = NULL;
3655
3656 if (!agent->valid()) {
3657 char buffer[JVM_MAXPATHLEN];
3658 char ebuf[1024];
3659 const char *name = agent->name();
3660 const char *msg = "Could not find agent library ";
3661
3662 // First check to see if agent is statically linked into executable
3663 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3664 library = agent->os_lib();
3665 } else if (agent->is_absolute_path()) {
3666 library = os::dll_load(name, ebuf, sizeof ebuf);
3667 if (library == NULL) {
3668 const char *sub_msg = " in absolute path, with error: ";
3669 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3670 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3671 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3672 // If we can't find the agent, exit.
3673 vm_exit_during_initialization(buf, NULL);
3674 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3675 }
3676 } else {
3677 // Try to load the agent from the standard dll directory
3678 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3679 name)) {
3680 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3681 }
3682 if (library == NULL) { // Try the local directory
3683 char ns[1] = {0};
3684 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3685 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3686 }
3687 if (library == NULL) {
3688 const char *sub_msg = " on the library path, with error: ";
3689 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3690 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3691 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3692 // If we can't find the agent, exit.
3693 vm_exit_during_initialization(buf, NULL);
3694 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3695 }
3696 }
3697 }
3698 agent->set_os_lib(library);
3699 agent->set_valid();
3700 }
3701
3702 // Find the OnLoad function.
3703 on_load_entry =
3704 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3705 false,
3706 on_load_symbols,
3707 num_symbol_entries));
3708 return on_load_entry;
3709 }
3710
3711 // Find the JVM_OnLoad entry point
3712 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3713 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3714 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3715 }
3716
3717 // Find the Agent_OnLoad entry point
3718 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3719 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3720 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3721 }
3722
3723 // For backwards compatibility with -Xrun
3724 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3725 // treated like -agentpath:
3726 // Must be called before agent libraries are created
3727 void Threads::convert_vm_init_libraries_to_agents() {
3728 AgentLibrary* agent;
3729 AgentLibrary* next;
3730
3731 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3732 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3733 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3734
3735 // If there is an JVM_OnLoad function it will get called later,
3736 // otherwise see if there is an Agent_OnLoad
3737 if (on_load_entry == NULL) {
3738 on_load_entry = lookup_agent_on_load(agent);
3739 if (on_load_entry != NULL) {
3740 // switch it to the agent list -- so that Agent_OnLoad will be called,
3741 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3742 Arguments::convert_library_to_agent(agent);
3743 } else {
3744 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3745 }
3746 }
3747 }
3748 }
3749
3750 // Create agents for -agentlib: -agentpath: and converted -Xrun
3751 // Invokes Agent_OnLoad
3752 // Called very early -- before JavaThreads exist
3753 void Threads::create_vm_init_agents() {
3754 extern struct JavaVM_ main_vm;
3755 AgentLibrary* agent;
3756
3757 JvmtiExport::enter_onload_phase();
3758
3759 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3760 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3761
3762 if (on_load_entry != NULL) {
3763 // Invoke the Agent_OnLoad function
3764 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3765 if (err != JNI_OK) {
3766 vm_exit_during_initialization("agent library failed to init", agent->name());
3767 }
3768 } else {
3769 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3770 }
3771 }
3772 JvmtiExport::enter_primordial_phase();
3773 }
3774
3775 extern "C" {
3776 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3777 }
3778
3779 void Threads::shutdown_vm_agents() {
3780 // Send any Agent_OnUnload notifications
3781 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3782 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3783 extern struct JavaVM_ main_vm;
3784 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3785
3786 // Find the Agent_OnUnload function.
3787 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3788 os::find_agent_function(agent,
3789 false,
3790 on_unload_symbols,
3791 num_symbol_entries));
3792
3793 // Invoke the Agent_OnUnload function
3794 if (unload_entry != NULL) {
3795 JavaThread* thread = JavaThread::current();
3796 ThreadToNativeFromVM ttn(thread);
3797 HandleMark hm(thread);
3798 (*unload_entry)(&main_vm);
3799 }
3800 }
3801 }
3802
3803 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3804 // Invokes JVM_OnLoad
3805 void Threads::create_vm_init_libraries() {
3806 extern struct JavaVM_ main_vm;
3807 AgentLibrary* agent;
3808
3809 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3810 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3811
3812 if (on_load_entry != NULL) {
3813 // Invoke the JVM_OnLoad function
3814 JavaThread* thread = JavaThread::current();
3815 ThreadToNativeFromVM ttn(thread);
3816 HandleMark hm(thread);
3817 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3818 if (err != JNI_OK) {
3819 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3820 }
3821 } else {
3822 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3823 }
3824 }
3825 }
3826
3827 // Last thread running calls java.lang.Shutdown.shutdown()
3828 void JavaThread::invoke_shutdown_hooks() {
3829 HandleMark hm(this);
3830
3831 // We could get here with a pending exception, if so clear it now.
3832 if (this->has_pending_exception()) {
3833 this->clear_pending_exception();
3834 }
3835
3836 EXCEPTION_MARK;
3837 Klass* k =
3838 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3839 THREAD);
3840 if (k != NULL) {
3841 // SystemDictionary::resolve_or_null will return null if there was
3842 // an exception. If we cannot load the Shutdown class, just don't
3843 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3844 // and finalizers (if runFinalizersOnExit is set) won't be run.
3845 // Note that if a shutdown hook was registered or runFinalizersOnExit
3846 // was called, the Shutdown class would have already been loaded
3847 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3848 instanceKlassHandle shutdown_klass (THREAD, k);
3849 JavaValue result(T_VOID);
3850 JavaCalls::call_static(&result,
3851 shutdown_klass,
3852 vmSymbols::shutdown_method_name(),
3853 vmSymbols::void_method_signature(),
3854 THREAD);
3855 }
3856 CLEAR_PENDING_EXCEPTION;
3857 }
3858
3859 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3860 // the program falls off the end of main(). Another VM exit path is through
3861 // vm_exit() when the program calls System.exit() to return a value or when
3862 // there is a serious error in VM. The two shutdown paths are not exactly
3863 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3864 // and VM_Exit op at VM level.
3865 //
3866 // Shutdown sequence:
3867 // + Shutdown native memory tracking if it is on
3868 // + Wait until we are the last non-daemon thread to execute
3869 // <-- every thing is still working at this moment -->
3870 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3871 // shutdown hooks, run finalizers if finalization-on-exit
3872 // + Call before_exit(), prepare for VM exit
3873 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3874 // currently the only user of this mechanism is File.deleteOnExit())
3875 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3876 // post thread end and vm death events to JVMTI,
3877 // stop signal thread
3878 // + Call JavaThread::exit(), it will:
3879 // > release JNI handle blocks, remove stack guard pages
3880 // > remove this thread from Threads list
3881 // <-- no more Java code from this thread after this point -->
3882 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3883 // the compiler threads at safepoint
3884 // <-- do not use anything that could get blocked by Safepoint -->
3885 // + Disable tracing at JNI/JVM barriers
3886 // + Set _vm_exited flag for threads that are still running native code
3887 // + Delete this thread
3888 // + Call exit_globals()
3889 // > deletes tty
3890 // > deletes PerfMemory resources
3891 // + Return to caller
3892
3893 bool Threads::destroy_vm() {
3894 JavaThread* thread = JavaThread::current();
3895
3896 #ifdef ASSERT
3897 _vm_complete = false;
3898 #endif
3899 // Wait until we are the last non-daemon thread to execute
3900 { MutexLocker nu(Threads_lock);
3901 while (Threads::number_of_non_daemon_threads() > 1)
3902 // This wait should make safepoint checks, wait without a timeout,
3903 // and wait as a suspend-equivalent condition.
3904 //
3905 // Note: If the FlatProfiler is running and this thread is waiting
3906 // for another non-daemon thread to finish, then the FlatProfiler
3907 // is waiting for the external suspend request on this thread to
3908 // complete. wait_for_ext_suspend_completion() will eventually
3909 // timeout, but that takes time. Making this wait a suspend-
3910 // equivalent condition solves that timeout problem.
3911 //
3912 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3913 Mutex::_as_suspend_equivalent_flag);
3914 }
3915
3916 // Hang forever on exit if we are reporting an error.
3917 if (ShowMessageBoxOnError && is_error_reported()) {
3918 os::infinite_sleep();
3919 }
3920 os::wait_for_keypress_at_exit();
3921
3922 // run Java level shutdown hooks
3923 thread->invoke_shutdown_hooks();
3924
3925 before_exit(thread);
3926
3927 thread->exit(true);
3928
3929 // Stop VM thread.
3930 {
3931 // 4945125 The vm thread comes to a safepoint during exit.
3932 // GC vm_operations can get caught at the safepoint, and the
3933 // heap is unparseable if they are caught. Grab the Heap_lock
3934 // to prevent this. The GC vm_operations will not be able to
3935 // queue until after the vm thread is dead. After this point,
3936 // we'll never emerge out of the safepoint before the VM exits.
3937
3938 MutexLocker ml(Heap_lock);
3939
3940 VMThread::wait_for_vm_thread_exit();
3941 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3942 VMThread::destroy();
3943 }
3944
3945 // clean up ideal graph printers
3946 #if defined(COMPILER2) && !defined(PRODUCT)
3947 IdealGraphPrinter::clean_up();
3948 #endif
3949
3950 // Now, all Java threads are gone except daemon threads. Daemon threads
3951 // running Java code or in VM are stopped by the Safepoint. However,
3952 // daemon threads executing native code are still running. But they
3953 // will be stopped at native=>Java/VM barriers. Note that we can't
3954 // simply kill or suspend them, as it is inherently deadlock-prone.
3955
3956 #ifndef PRODUCT
3957 // disable function tracing at JNI/JVM barriers
3958 TraceJNICalls = false;
3959 TraceJVMCalls = false;
3960 TraceRuntimeCalls = false;
3961 #endif
3962
3963 VM_Exit::set_vm_exited();
3964
3965 notify_vm_shutdown();
3966
3967 delete thread;
3968
3969 // exit_globals() will delete tty
3970 exit_globals();
3971
3972 return true;
3973 }
3974
3975
3976 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3977 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3978 return is_supported_jni_version(version);
3979 }
3980
3981
3982 jboolean Threads::is_supported_jni_version(jint version) {
3983 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3984 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3985 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3986 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3987 return JNI_FALSE;
3988 }
3989
3990
3991 void Threads::add(JavaThread* p, bool force_daemon) {
3992 // The threads lock must be owned at this point
3993 assert_locked_or_safepoint(Threads_lock);
3994
3995 // See the comment for this method in thread.hpp for its purpose and
3996 // why it is called here.
3997 p->initialize_queues();
3998 p->set_next(_thread_list);
3999 _thread_list = p;
4000 _number_of_threads++;
4001 oop threadObj = p->threadObj();
4002 bool daemon = true;
4003 // Bootstrapping problem: threadObj can be null for initial
4004 // JavaThread (or for threads attached via JNI)
4005 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4006 _number_of_non_daemon_threads++;
4007 daemon = false;
4008 }
4009
4010 p->set_safepoint_visible(true);
4011
4012 ThreadService::add_thread(p, daemon);
4013
4014 // Possible GC point.
4015 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4016 }
4017
4018 void Threads::remove(JavaThread* p) {
4019 // Extra scope needed for Thread_lock, so we can check
4020 // that we do not remove thread without safepoint code notice
4021 { MutexLocker ml(Threads_lock);
4022
4023 assert(includes(p), "p must be present");
4024
4025 JavaThread* current = _thread_list;
4026 JavaThread* prev = NULL;
4027
4028 while (current != p) {
4029 prev = current;
4030 current = current->next();
4031 }
4032
4033 if (prev) {
4034 prev->set_next(current->next());
4035 } else {
4036 _thread_list = p->next();
4037 }
4038 _number_of_threads--;
4039 oop threadObj = p->threadObj();
4040 bool daemon = true;
4041 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4042 _number_of_non_daemon_threads--;
4043 daemon = false;
4044
4045 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4046 // on destroy_vm will wake up.
4047 if (number_of_non_daemon_threads() == 1)
4048 Threads_lock->notify_all();
4049 }
4050 ThreadService::remove_thread(p, daemon);
4051
4052 // Make sure that safepoint code disregard this thread. This is needed since
4053 // the thread might mess around with locks after this point. This can cause it
4054 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4055 // of this thread since it is removed from the queue.
4056 p->set_terminated_value();
4057
4058 // Now, this thread is not visible to safepoint
4059 p->set_safepoint_visible(false);
4060 // once the thread becomes safepoint invisible, we can not use its per-thread
4061 // recorder. And Threads::do_threads() no longer walks this thread, so we have
4062 // to release its per-thread recorder here.
4063 MemTracker::thread_exiting(p);
4064 } // unlock Threads_lock
4065
4066 // Since Events::log uses a lock, we grab it outside the Threads_lock
4067 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4068 }
4069
4070 // Threads_lock must be held when this is called (or must be called during a safepoint)
4071 bool Threads::includes(JavaThread* p) {
4072 assert(Threads_lock->is_locked(), "sanity check");
4073 ALL_JAVA_THREADS(q) {
4074 if (q == p) {
4075 return true;
4076 }
4077 }
4078 return false;
4079 }
4080
4081 // Operations on the Threads list for GC. These are not explicitly locked,
4082 // but the garbage collector must provide a safe context for them to run.
4083 // In particular, these things should never be called when the Threads_lock
4084 // is held by some other thread. (Note: the Safepoint abstraction also
4085 // uses the Threads_lock to guarantee this property. It also makes sure that
4086 // all threads gets blocked when exiting or starting).
4087
4088 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4089 ALL_JAVA_THREADS(p) {
4090 p->oops_do(f, cld_f, cf);
4091 }
4092 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4093 }
4094
4095 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4096 // Introduce a mechanism allowing parallel threads to claim threads as
4097 // root groups. Overhead should be small enough to use all the time,
4098 // even in sequential code.
4099 SharedHeap* sh = SharedHeap::heap();
4100 // Cannot yet substitute active_workers for n_par_threads
4101 // because of G1CollectedHeap::verify() use of
4102 // SharedHeap::process_roots(). n_par_threads == 0 will
4103 // turn off parallelism in process_roots while active_workers
4104 // is being used for parallelism elsewhere.
4105 bool is_par = sh->n_par_threads() > 0;
4106 assert(!is_par ||
4107 (SharedHeap::heap()->n_par_threads() ==
4108 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4109 int cp = SharedHeap::heap()->strong_roots_parity();
4110 ALL_JAVA_THREADS(p) {
4111 if (p->claim_oops_do(is_par, cp)) {
4112 p->oops_do(f, cld_f, cf);
4113 }
4114 }
4115 VMThread* vmt = VMThread::vm_thread();
4116 if (vmt->claim_oops_do(is_par, cp)) {
4117 vmt->oops_do(f, cld_f, cf);
4118 }
4119 }
4120
4121 #if INCLUDE_ALL_GCS
4122 // Used by ParallelScavenge
4123 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4124 ALL_JAVA_THREADS(p) {
4125 q->enqueue(new ThreadRootsTask(p));
4126 }
4127 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4128 }
4129
4130 // Used by Parallel Old
4131 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4132 ALL_JAVA_THREADS(p) {
4133 q->enqueue(new ThreadRootsMarkingTask(p));
4134 }
4135 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4136 }
4137 #endif // INCLUDE_ALL_GCS
4138
4139 void Threads::nmethods_do(CodeBlobClosure* cf) {
4140 ALL_JAVA_THREADS(p) {
4141 p->nmethods_do(cf);
4142 }
4143 VMThread::vm_thread()->nmethods_do(cf);
4144 }
4145
4146 void Threads::metadata_do(void f(Metadata*)) {
4147 ALL_JAVA_THREADS(p) {
4148 p->metadata_do(f);
4149 }
4150 }
4151
4152 void Threads::gc_epilogue() {
4153 ALL_JAVA_THREADS(p) {
4154 p->gc_epilogue();
4155 }
4156 }
4157
4158 void Threads::gc_prologue() {
4159 ALL_JAVA_THREADS(p) {
4160 p->gc_prologue();
4161 }
4162 }
4163
4164 void Threads::deoptimized_wrt_marked_nmethods() {
4165 ALL_JAVA_THREADS(p) {
4166 p->deoptimized_wrt_marked_nmethods();
4167 }
4168 }
4169
4170
4171 // Get count Java threads that are waiting to enter the specified monitor.
4172 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4173 address monitor, bool doLock) {
4174 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4175 "must grab Threads_lock or be at safepoint");
4176 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4177
4178 int i = 0;
4179 {
4180 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4181 ALL_JAVA_THREADS(p) {
4182 if (p->is_Compiler_thread()) continue;
4183
4184 address pending = (address)p->current_pending_monitor();
4185 if (pending == monitor) { // found a match
4186 if (i < count) result->append(p); // save the first count matches
4187 i++;
4188 }
4189 }
4190 }
4191 return result;
4192 }
4193
4194
4195 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4196 assert(doLock ||
4197 Threads_lock->owned_by_self() ||
4198 SafepointSynchronize::is_at_safepoint(),
4199 "must grab Threads_lock or be at safepoint");
4200
4201 // NULL owner means not locked so we can skip the search
4202 if (owner == NULL) return NULL;
4203
4204 {
4205 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4206 ALL_JAVA_THREADS(p) {
4207 // first, see if owner is the address of a Java thread
4208 if (owner == (address)p) return p;
4209 }
4210 }
4211 // Cannot assert on lack of success here since this function may be
4212 // used by code that is trying to report useful problem information
4213 // like deadlock detection.
4214 if (UseHeavyMonitors) return NULL;
4215
4216 //
4217 // If we didn't find a matching Java thread and we didn't force use of
4218 // heavyweight monitors, then the owner is the stack address of the
4219 // Lock Word in the owning Java thread's stack.
4220 //
4221 JavaThread* the_owner = NULL;
4222 {
4223 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4224 ALL_JAVA_THREADS(q) {
4225 if (q->is_lock_owned(owner)) {
4226 the_owner = q;
4227 break;
4228 }
4229 }
4230 }
4231 // cannot assert on lack of success here; see above comment
4232 return the_owner;
4233 }
4234
4235 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4236 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4237 char buf[32];
4238 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4239
4240 st->print_cr("Full thread dump %s (%s %s):",
4241 Abstract_VM_Version::vm_name(),
4242 Abstract_VM_Version::vm_release(),
4243 Abstract_VM_Version::vm_info_string()
4244 );
4245 st->cr();
4246
4247 #if INCLUDE_ALL_GCS
4248 // Dump concurrent locks
4249 ConcurrentLocksDump concurrent_locks;
4250 if (print_concurrent_locks) {
4251 concurrent_locks.dump_at_safepoint();
4252 }
4253 #endif // INCLUDE_ALL_GCS
4254
4255 ALL_JAVA_THREADS(p) {
4256 ResourceMark rm;
4257 p->print_on(st);
4258 if (print_stacks) {
4259 if (internal_format) {
4260 p->trace_stack();
4261 } else {
4262 p->print_stack_on(st);
4263 }
4264 }
4265 st->cr();
4266 #if INCLUDE_ALL_GCS
4267 if (print_concurrent_locks) {
4268 concurrent_locks.print_locks_on(p, st);
4269 }
4270 #endif // INCLUDE_ALL_GCS
4271 }
4272
4273 VMThread::vm_thread()->print_on(st);
4274 st->cr();
4275 Universe::heap()->print_gc_threads_on(st);
4276 WatcherThread* wt = WatcherThread::watcher_thread();
4277 if (wt != NULL) {
4278 wt->print_on(st);
4279 st->cr();
4280 }
4281 CompileBroker::print_compiler_threads_on(st);
4282 st->flush();
4283 }
4284
4285 // Threads::print_on_error() is called by fatal error handler. It's possible
4286 // that VM is not at safepoint and/or current thread is inside signal handler.
4287 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4288 // memory (even in resource area), it might deadlock the error handler.
4289 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4290 bool found_current = false;
4291 st->print_cr("Java Threads: ( => current thread )");
4292 ALL_JAVA_THREADS(thread) {
4293 bool is_current = (current == thread);
4294 found_current = found_current || is_current;
4295
4296 st->print("%s", is_current ? "=>" : " ");
4297
4298 st->print(PTR_FORMAT, thread);
4299 st->print(" ");
4300 thread->print_on_error(st, buf, buflen);
4301 st->cr();
4302 }
4303 st->cr();
4304
4305 st->print_cr("Other Threads:");
4306 if (VMThread::vm_thread()) {
4307 bool is_current = (current == VMThread::vm_thread());
4308 found_current = found_current || is_current;
4309 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4310
4311 st->print(PTR_FORMAT, VMThread::vm_thread());
4312 st->print(" ");
4313 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4314 st->cr();
4315 }
4316 WatcherThread* wt = WatcherThread::watcher_thread();
4317 if (wt != NULL) {
4318 bool is_current = (current == wt);
4319 found_current = found_current || is_current;
4320 st->print("%s", is_current ? "=>" : " ");
4321
4322 st->print(PTR_FORMAT, wt);
4323 st->print(" ");
4324 wt->print_on_error(st, buf, buflen);
4325 st->cr();
4326 }
4327 if (!found_current) {
4328 st->cr();
4329 st->print("=>" PTR_FORMAT " (exited) ", current);
4330 current->print_on_error(st, buf, buflen);
4331 st->cr();
4332 }
4333 }
4334
4335 // Internal SpinLock and Mutex
4336 // Based on ParkEvent
4337
4338 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4339 //
4340 // We employ SpinLocks _only for low-contention, fixed-length
4341 // short-duration critical sections where we're concerned
4342 // about native mutex_t or HotSpot Mutex:: latency.
4343 // The mux construct provides a spin-then-block mutual exclusion
4344 // mechanism.
4345 //
4346 // Testing has shown that contention on the ListLock guarding gFreeList
4347 // is common. If we implement ListLock as a simple SpinLock it's common
4348 // for the JVM to devolve to yielding with little progress. This is true
4349 // despite the fact that the critical sections protected by ListLock are
4350 // extremely short.
4351 //
4352 // TODO-FIXME: ListLock should be of type SpinLock.
4353 // We should make this a 1st-class type, integrated into the lock
4354 // hierarchy as leaf-locks. Critically, the SpinLock structure
4355 // should have sufficient padding to avoid false-sharing and excessive
4356 // cache-coherency traffic.
4357
4358
4359 typedef volatile int SpinLockT;
4360
4361 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4362 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4363 return; // normal fast-path return
4364 }
4365
4366 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4367 TEVENT(SpinAcquire - ctx);
4368 int ctr = 0;
4369 int Yields = 0;
4370 for (;;) {
4371 while (*adr != 0) {
4372 ++ctr;
4373 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4374 if (Yields > 5) {
4375 os::naked_short_sleep(1);
4376 } else {
4377 os::naked_yield();
4378 ++Yields;
4379 }
4380 } else {
4381 SpinPause();
4382 }
4383 }
4384 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4385 }
4386 }
4387
4388 void Thread::SpinRelease (volatile int * adr) {
4389 assert(*adr != 0, "invariant");
4390 OrderAccess::fence(); // guarantee at least release consistency.
4391 // Roach-motel semantics.
4392 // It's safe if subsequent LDs and STs float "up" into the critical section,
4393 // but prior LDs and STs within the critical section can't be allowed
4394 // to reorder or float past the ST that releases the lock.
4395 // Loads and stores in the critical section - which appear in program
4396 // order before the store that releases the lock - must also appear
4397 // before the store that releases the lock in memory visibility order.
4398 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4399 // the ST of 0 into the lock-word which releases the lock, so fence
4400 // more than covers this on all platforms.
4401 *adr = 0;
4402 }
4403
4404 // muxAcquire and muxRelease:
4405 //
4406 // * muxAcquire and muxRelease support a single-word lock-word construct.
4407 // The LSB of the word is set IFF the lock is held.
4408 // The remainder of the word points to the head of a singly-linked list
4409 // of threads blocked on the lock.
4410 //
4411 // * The current implementation of muxAcquire-muxRelease uses its own
4412 // dedicated Thread._MuxEvent instance. If we're interested in
4413 // minimizing the peak number of extant ParkEvent instances then
4414 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4415 // as certain invariants were satisfied. Specifically, care would need
4416 // to be taken with regards to consuming unpark() "permits".
4417 // A safe rule of thumb is that a thread would never call muxAcquire()
4418 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4419 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4420 // consume an unpark() permit intended for monitorenter, for instance.
4421 // One way around this would be to widen the restricted-range semaphore
4422 // implemented in park(). Another alternative would be to provide
4423 // multiple instances of the PlatformEvent() for each thread. One
4424 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4425 //
4426 // * Usage:
4427 // -- Only as leaf locks
4428 // -- for short-term locking only as muxAcquire does not perform
4429 // thread state transitions.
4430 //
4431 // Alternatives:
4432 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4433 // but with parking or spin-then-park instead of pure spinning.
4434 // * Use Taura-Oyama-Yonenzawa locks.
4435 // * It's possible to construct a 1-0 lock if we encode the lockword as
4436 // (List,LockByte). Acquire will CAS the full lockword while Release
4437 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4438 // acquiring threads use timers (ParkTimed) to detect and recover from
4439 // the stranding window. Thread/Node structures must be aligned on 256-byte
4440 // boundaries by using placement-new.
4441 // * Augment MCS with advisory back-link fields maintained with CAS().
4442 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4443 // The validity of the backlinks must be ratified before we trust the value.
4444 // If the backlinks are invalid the exiting thread must back-track through the
4445 // the forward links, which are always trustworthy.
4446 // * Add a successor indication. The LockWord is currently encoded as
4447 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4448 // to provide the usual futile-wakeup optimization.
4449 // See RTStt for details.
4450 // * Consider schedctl.sc_nopreempt to cover the critical section.
4451 //
4452
4453
4454 typedef volatile intptr_t MutexT; // Mux Lock-word
4455 enum MuxBits { LOCKBIT = 1 };
4456
4457 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4458 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4459 if (w == 0) return;
4460 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4461 return;
4462 }
4463
4464 TEVENT(muxAcquire - Contention);
4465 ParkEvent * const Self = Thread::current()->_MuxEvent;
4466 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4467 for (;;) {
4468 int its = (os::is_MP() ? 100 : 0) + 1;
4469
4470 // Optional spin phase: spin-then-park strategy
4471 while (--its >= 0) {
4472 w = *Lock;
4473 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4474 return;
4475 }
4476 }
4477
4478 Self->reset();
4479 Self->OnList = intptr_t(Lock);
4480 // The following fence() isn't _strictly necessary as the subsequent
4481 // CAS() both serializes execution and ratifies the fetched *Lock value.
4482 OrderAccess::fence();
4483 for (;;) {
4484 w = *Lock;
4485 if ((w & LOCKBIT) == 0) {
4486 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4487 Self->OnList = 0; // hygiene - allows stronger asserts
4488 return;
4489 }
4490 continue; // Interference -- *Lock changed -- Just retry
4491 }
4492 assert(w & LOCKBIT, "invariant");
4493 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4494 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4495 }
4496
4497 while (Self->OnList != 0) {
4498 Self->park();
4499 }
4500 }
4501 }
4502
4503 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4504 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4505 if (w == 0) return;
4506 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4507 return;
4508 }
4509
4510 TEVENT(muxAcquire - Contention);
4511 ParkEvent * ReleaseAfter = NULL;
4512 if (ev == NULL) {
4513 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4514 }
4515 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4516 for (;;) {
4517 guarantee(ev->OnList == 0, "invariant");
4518 int its = (os::is_MP() ? 100 : 0) + 1;
4519
4520 // Optional spin phase: spin-then-park strategy
4521 while (--its >= 0) {
4522 w = *Lock;
4523 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4524 if (ReleaseAfter != NULL) {
4525 ParkEvent::Release(ReleaseAfter);
4526 }
4527 return;
4528 }
4529 }
4530
4531 ev->reset();
4532 ev->OnList = intptr_t(Lock);
4533 // The following fence() isn't _strictly necessary as the subsequent
4534 // CAS() both serializes execution and ratifies the fetched *Lock value.
4535 OrderAccess::fence();
4536 for (;;) {
4537 w = *Lock;
4538 if ((w & LOCKBIT) == 0) {
4539 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4540 ev->OnList = 0;
4541 // We call ::Release while holding the outer lock, thus
4542 // artificially lengthening the critical section.
4543 // Consider deferring the ::Release() until the subsequent unlock(),
4544 // after we've dropped the outer lock.
4545 if (ReleaseAfter != NULL) {
4546 ParkEvent::Release(ReleaseAfter);
4547 }
4548 return;
4549 }
4550 continue; // Interference -- *Lock changed -- Just retry
4551 }
4552 assert(w & LOCKBIT, "invariant");
4553 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4554 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4555 }
4556
4557 while (ev->OnList != 0) {
4558 ev->park();
4559 }
4560 }
4561 }
4562
4563 // Release() must extract a successor from the list and then wake that thread.
4564 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4565 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4566 // Release() would :
4567 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4568 // (B) Extract a successor from the private list "in-hand"
4569 // (C) attempt to CAS() the residual back into *Lock over null.
4570 // If there were any newly arrived threads and the CAS() would fail.
4571 // In that case Release() would detach the RATs, re-merge the list in-hand
4572 // with the RATs and repeat as needed. Alternately, Release() might
4573 // detach and extract a successor, but then pass the residual list to the wakee.
4574 // The wakee would be responsible for reattaching and remerging before it
4575 // competed for the lock.
4576 //
4577 // Both "pop" and DMR are immune from ABA corruption -- there can be
4578 // multiple concurrent pushers, but only one popper or detacher.
4579 // This implementation pops from the head of the list. This is unfair,
4580 // but tends to provide excellent throughput as hot threads remain hot.
4581 // (We wake recently run threads first).
4582 //
4583 // All paths through muxRelease() will execute a CAS.
4584 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4585 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4586 // executed within the critical section are complete and globally visible before the
4587 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4588 void Thread::muxRelease (volatile intptr_t * Lock) {
4589 for (;;) {
4590 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4591 assert(w & LOCKBIT, "invariant");
4592 if (w == LOCKBIT) return;
4593 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4594 assert(List != NULL, "invariant");
4595 assert(List->OnList == intptr_t(Lock), "invariant");
4596 ParkEvent * const nxt = List->ListNext;
4597 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4598
4599 // The following CAS() releases the lock and pops the head element.
4600 // The CAS() also ratifies the previously fetched lock-word value.
4601 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4602 continue;
4603 }
4604 List->OnList = 0;
4605 OrderAccess::fence();
4606 List->unpark();
4607 return;
4608 }
4609 }
4610
4611
4612 void Threads::verify() {
4613 ALL_JAVA_THREADS(p) {
4614 p->verify();
4615 }
4616 VMThread* thread = VMThread::vm_thread();
4617 if (thread != NULL) thread->verify();
4618 }