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 {
1350 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1351 _should_terminate = true;
1352 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1353
1354 WatcherThread* watcher = watcher_thread();
1355 if (watcher != NULL)
1356 watcher->unpark();
1357 }
1358
1359 // it is ok to take late safepoints here, if needed
1360 MutexLocker mu(Terminator_lock);
1361
1362 while (watcher_thread() != NULL) {
1363 // This wait should make safepoint checks, wait without a timeout,
1364 // and wait as a suspend-equivalent condition.
1365 //
1366 // Note: If the FlatProfiler is running, then this thread is waiting
1367 // for the WatcherThread to terminate and the WatcherThread, via the
1368 // FlatProfiler task, is waiting for the external suspend request on
1369 // this thread to complete. wait_for_ext_suspend_completion() will
1370 // eventually timeout, but that takes time. Making this wait a
1371 // suspend-equivalent condition solves that timeout problem.
1372 //
1373 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1374 Mutex::_as_suspend_equivalent_flag);
1375 }
1376 }
1377
1378 void WatcherThread::unpark() {
1379 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1380 PeriodicTask_lock->notify();
1381 }
1382
1383 void WatcherThread::print_on(outputStream* st) const {
1384 st->print("\"%s\" ", name());
1385 Thread::print_on(st);
1386 st->cr();
1387 }
1388
1389 // ======= JavaThread ========
1390
1391 // A JavaThread is a normal Java thread
1392
1393 void JavaThread::initialize() {
1394 // Initialize fields
1395
1396 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1397 set_claimed_par_id(UINT_MAX);
1398
1399 set_saved_exception_pc(NULL);
1400 set_threadObj(NULL);
1401 _anchor.clear();
1402 set_entry_point(NULL);
1403 set_jni_functions(jni_functions());
1404 set_callee_target(NULL);
1405 set_vm_result(NULL);
1406 set_vm_result_2(NULL);
1407 set_vframe_array_head(NULL);
1408 set_vframe_array_last(NULL);
1409 set_deferred_locals(NULL);
1410 set_deopt_mark(NULL);
1411 set_deopt_nmethod(NULL);
1412 clear_must_deopt_id();
1413 set_monitor_chunks(NULL);
1414 set_next(NULL);
1415 set_thread_state(_thread_new);
1416 #if INCLUDE_NMT
1417 set_recorder(NULL);
1418 #endif
1419 _terminated = _not_terminated;
1420 _privileged_stack_top = NULL;
1421 _array_for_gc = NULL;
1422 _suspend_equivalent = false;
1423 _in_deopt_handler = 0;
1424 _doing_unsafe_access = false;
1425 _stack_guard_state = stack_guard_unused;
1426 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1427 _exception_pc = 0;
1428 _exception_handler_pc = 0;
1429 _is_method_handle_return = 0;
1430 _jvmti_thread_state= NULL;
1431 _should_post_on_exceptions_flag = JNI_FALSE;
1432 _jvmti_get_loaded_classes_closure = NULL;
1433 _interp_only_mode = 0;
1434 _special_runtime_exit_condition = _no_async_condition;
1435 _pending_async_exception = NULL;
1436 _thread_stat = NULL;
1437 _thread_stat = new ThreadStatistics();
1438 _blocked_on_compilation = false;
1439 _jni_active_critical = 0;
1440 _pending_jni_exception_check_fn = NULL;
1441 _do_not_unlock_if_synchronized = false;
1442 _cached_monitor_info = NULL;
1443 _parker = Parker::Allocate(this);
1444
1445 #ifndef PRODUCT
1446 _jmp_ring_index = 0;
1447 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1448 record_jump(NULL, NULL, NULL, 0);
1449 }
1450 #endif /* PRODUCT */
1451
1452 set_thread_profiler(NULL);
1453 if (FlatProfiler::is_active()) {
1454 // This is where we would decide to either give each thread it's own profiler
1455 // or use one global one from FlatProfiler,
1456 // or up to some count of the number of profiled threads, etc.
1457 ThreadProfiler* pp = new ThreadProfiler();
1458 pp->engage();
1459 set_thread_profiler(pp);
1460 }
1461
1462 // Setup safepoint state info for this thread
1463 ThreadSafepointState::create(this);
1464
1465 debug_only(_java_call_counter = 0);
1466
1467 // JVMTI PopFrame support
1468 _popframe_condition = popframe_inactive;
1469 _popframe_preserved_args = NULL;
1470 _popframe_preserved_args_size = 0;
1471
1472 pd_initialize();
1473 }
1474
1475 #if INCLUDE_ALL_GCS
1476 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1477 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1478 #endif // INCLUDE_ALL_GCS
1479
1480 JavaThread::JavaThread(bool is_attaching_via_jni) :
1481 Thread()
1482 #if INCLUDE_ALL_GCS
1483 , _satb_mark_queue(&_satb_mark_queue_set),
1484 _dirty_card_queue(&_dirty_card_queue_set)
1485 #endif // INCLUDE_ALL_GCS
1486 {
1487 initialize();
1488 if (is_attaching_via_jni) {
1489 _jni_attach_state = _attaching_via_jni;
1490 } else {
1491 _jni_attach_state = _not_attaching_via_jni;
1492 }
1493 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1494 _safepoint_visible = false;
1495 }
1496
1497 bool JavaThread::reguard_stack(address cur_sp) {
1498 if (_stack_guard_state != stack_guard_yellow_disabled) {
1499 return true; // Stack already guarded or guard pages not needed.
1500 }
1501
1502 if (register_stack_overflow()) {
1503 // For those architectures which have separate register and
1504 // memory stacks, we must check the register stack to see if
1505 // it has overflowed.
1506 return false;
1507 }
1508
1509 // Java code never executes within the yellow zone: the latter is only
1510 // there to provoke an exception during stack banging. If java code
1511 // is executing there, either StackShadowPages should be larger, or
1512 // some exception code in c1, c2 or the interpreter isn't unwinding
1513 // when it should.
1514 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1515
1516 enable_stack_yellow_zone();
1517 return true;
1518 }
1519
1520 bool JavaThread::reguard_stack(void) {
1521 return reguard_stack(os::current_stack_pointer());
1522 }
1523
1524
1525 void JavaThread::block_if_vm_exited() {
1526 if (_terminated == _vm_exited) {
1527 // _vm_exited is set at safepoint, and Threads_lock is never released
1528 // we will block here forever
1529 Threads_lock->lock_without_safepoint_check();
1530 ShouldNotReachHere();
1531 }
1532 }
1533
1534
1535 // Remove this ifdef when C1 is ported to the compiler interface.
1536 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1537
1538 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1539 Thread()
1540 #if INCLUDE_ALL_GCS
1541 , _satb_mark_queue(&_satb_mark_queue_set),
1542 _dirty_card_queue(&_dirty_card_queue_set)
1543 #endif // INCLUDE_ALL_GCS
1544 {
1545 if (TraceThreadEvents) {
1546 tty->print_cr("creating thread %p", this);
1547 }
1548 initialize();
1549 _jni_attach_state = _not_attaching_via_jni;
1550 set_entry_point(entry_point);
1551 // Create the native thread itself.
1552 // %note runtime_23
1553 os::ThreadType thr_type = os::java_thread;
1554 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1555 os::java_thread;
1556 os::create_thread(this, thr_type, stack_sz);
1557 _safepoint_visible = false;
1558 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1559 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1560 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1561 // the exception consists of creating the exception object & initializing it, initialization
1562 // will leave the VM via a JavaCall and then all locks must be unlocked).
1563 //
1564 // The thread is still suspended when we reach here. Thread must be explicit started
1565 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1566 // by calling Threads:add. The reason why this is not done here, is because the thread
1567 // object must be fully initialized (take a look at JVM_Start)
1568 }
1569
1570 JavaThread::~JavaThread() {
1571 if (TraceThreadEvents) {
1572 tty->print_cr("terminate thread %p", this);
1573 }
1574
1575 // By now, this thread should already be invisible to safepoint,
1576 // and its per-thread recorder also collected.
1577 assert(!is_safepoint_visible(), "wrong state");
1578 #if INCLUDE_NMT
1579 assert(get_recorder() == NULL, "Already collected");
1580 #endif // INCLUDE_NMT
1581
1582 // JSR166 -- return the parker to the free list
1583 Parker::Release(_parker);
1584 _parker = NULL;
1585
1586 // Free any remaining previous UnrollBlock
1587 vframeArray* old_array = vframe_array_last();
1588
1589 if (old_array != NULL) {
1590 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1591 old_array->set_unroll_block(NULL);
1592 delete old_info;
1593 delete old_array;
1594 }
1595
1596 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1597 if (deferred != NULL) {
1598 // This can only happen if thread is destroyed before deoptimization occurs.
1599 assert(deferred->length() != 0, "empty array!");
1600 do {
1601 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1602 deferred->remove_at(0);
1603 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1604 delete dlv;
1605 } while (deferred->length() != 0);
1606 delete deferred;
1607 }
1608
1609 // All Java related clean up happens in exit
1610 ThreadSafepointState::destroy(this);
1611 if (_thread_profiler != NULL) delete _thread_profiler;
1612 if (_thread_stat != NULL) delete _thread_stat;
1613 }
1614
1615
1616 // The first routine called by a new Java thread
1617 void JavaThread::run() {
1618 // initialize thread-local alloc buffer related fields
1619 this->initialize_tlab();
1620
1621 // used to test validity of stack trace backs
1622 this->record_base_of_stack_pointer();
1623
1624 // Record real stack base and size.
1625 this->record_stack_base_and_size();
1626
1627 // Initialize thread local storage; set before calling MutexLocker
1628 this->initialize_thread_local_storage();
1629
1630 this->create_stack_guard_pages();
1631
1632 this->cache_global_variables();
1633
1634 // Thread is now sufficient initialized to be handled by the safepoint code as being
1635 // in the VM. Change thread state from _thread_new to _thread_in_vm
1636 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1637
1638 assert(JavaThread::current() == this, "sanity check");
1639 assert(!Thread::current()->owns_locks(), "sanity check");
1640
1641 DTRACE_THREAD_PROBE(start, this);
1642
1643 // This operation might block. We call that after all safepoint checks for a new thread has
1644 // been completed.
1645 this->set_active_handles(JNIHandleBlock::allocate_block());
1646
1647 if (JvmtiExport::should_post_thread_life()) {
1648 JvmtiExport::post_thread_start(this);
1649 }
1650
1651 EventThreadStart event;
1652 if (event.should_commit()) {
1653 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1654 event.commit();
1655 }
1656
1657 // We call another function to do the rest so we are sure that the stack addresses used
1658 // from there will be lower than the stack base just computed
1659 thread_main_inner();
1660
1661 // Note, thread is no longer valid at this point!
1662 }
1663
1664
1665 void JavaThread::thread_main_inner() {
1666 assert(JavaThread::current() == this, "sanity check");
1667 assert(this->threadObj() != NULL, "just checking");
1668
1669 // Execute thread entry point unless this thread has a pending exception
1670 // or has been stopped before starting.
1671 // Note: Due to JVM_StopThread we can have pending exceptions already!
1672 if (!this->has_pending_exception() &&
1673 !java_lang_Thread::is_stillborn(this->threadObj())) {
1674 {
1675 ResourceMark rm(this);
1676 this->set_native_thread_name(this->get_thread_name());
1677 }
1678 HandleMark hm(this);
1679 this->entry_point()(this, this);
1680 }
1681
1682 DTRACE_THREAD_PROBE(stop, this);
1683
1684 this->exit(false);
1685 delete this;
1686 }
1687
1688
1689 static void ensure_join(JavaThread* thread) {
1690 // We do not need to grap the Threads_lock, since we are operating on ourself.
1691 Handle threadObj(thread, thread->threadObj());
1692 assert(threadObj.not_null(), "java thread object must exist");
1693 ObjectLocker lock(threadObj, thread);
1694 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1695 thread->clear_pending_exception();
1696 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1697 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1698 // Clear the native thread instance - this makes isAlive return false and allows the join()
1699 // to complete once we've done the notify_all below
1700 java_lang_Thread::set_thread(threadObj(), NULL);
1701 lock.notify_all(thread);
1702 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1703 thread->clear_pending_exception();
1704 }
1705
1706
1707 // For any new cleanup additions, please check to see if they need to be applied to
1708 // cleanup_failed_attach_current_thread as well.
1709 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1710 assert(this == JavaThread::current(), "thread consistency check");
1711
1712 HandleMark hm(this);
1713 Handle uncaught_exception(this, this->pending_exception());
1714 this->clear_pending_exception();
1715 Handle threadObj(this, this->threadObj());
1716 assert(threadObj.not_null(), "Java thread object should be created");
1717
1718 if (get_thread_profiler() != NULL) {
1719 get_thread_profiler()->disengage();
1720 ResourceMark rm;
1721 get_thread_profiler()->print(get_thread_name());
1722 }
1723
1724
1725 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1726 {
1727 EXCEPTION_MARK;
1728
1729 CLEAR_PENDING_EXCEPTION;
1730 }
1731 if (!destroy_vm) {
1732 if (uncaught_exception.not_null()) {
1733 EXCEPTION_MARK;
1734 // Call method Thread.dispatchUncaughtException().
1735 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1736 JavaValue result(T_VOID);
1737 JavaCalls::call_virtual(&result,
1738 threadObj, thread_klass,
1739 vmSymbols::dispatchUncaughtException_name(),
1740 vmSymbols::throwable_void_signature(),
1741 uncaught_exception,
1742 THREAD);
1743 if (HAS_PENDING_EXCEPTION) {
1744 ResourceMark rm(this);
1745 jio_fprintf(defaultStream::error_stream(),
1746 "\nException: %s thrown from the UncaughtExceptionHandler"
1747 " in thread \"%s\"\n",
1748 pending_exception()->klass()->external_name(),
1749 get_thread_name());
1750 CLEAR_PENDING_EXCEPTION;
1751 }
1752 }
1753
1754 // Called before the java thread exit since we want to read info
1755 // from java_lang_Thread object
1756 EventThreadEnd event;
1757 if (event.should_commit()) {
1758 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1759 event.commit();
1760 }
1761
1762 // Call after last event on thread
1763 EVENT_THREAD_EXIT(this);
1764
1765 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1766 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1767 // is deprecated anyhow.
1768 if (!is_Compiler_thread()) {
1769 int count = 3;
1770 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1771 EXCEPTION_MARK;
1772 JavaValue result(T_VOID);
1773 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1774 JavaCalls::call_virtual(&result,
1775 threadObj, thread_klass,
1776 vmSymbols::exit_method_name(),
1777 vmSymbols::void_method_signature(),
1778 THREAD);
1779 CLEAR_PENDING_EXCEPTION;
1780 }
1781 }
1782 // notify JVMTI
1783 if (JvmtiExport::should_post_thread_life()) {
1784 JvmtiExport::post_thread_end(this);
1785 }
1786
1787 // We have notified the agents that we are exiting, before we go on,
1788 // we must check for a pending external suspend request and honor it
1789 // in order to not surprise the thread that made the suspend request.
1790 while (true) {
1791 {
1792 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1793 if (!is_external_suspend()) {
1794 set_terminated(_thread_exiting);
1795 ThreadService::current_thread_exiting(this);
1796 break;
1797 }
1798 // Implied else:
1799 // Things get a little tricky here. We have a pending external
1800 // suspend request, but we are holding the SR_lock so we
1801 // can't just self-suspend. So we temporarily drop the lock
1802 // and then self-suspend.
1803 }
1804
1805 ThreadBlockInVM tbivm(this);
1806 java_suspend_self();
1807
1808 // We're done with this suspend request, but we have to loop around
1809 // and check again. Eventually we will get SR_lock without a pending
1810 // external suspend request and will be able to mark ourselves as
1811 // exiting.
1812 }
1813 // no more external suspends are allowed at this point
1814 } else {
1815 // before_exit() has already posted JVMTI THREAD_END events
1816 }
1817
1818 // Notify waiters on thread object. This has to be done after exit() is called
1819 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1820 // group should have the destroyed bit set before waiters are notified).
1821 ensure_join(this);
1822 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1823
1824 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1825 // held by this thread must be released. A detach operation must only
1826 // get here if there are no Java frames on the stack. Therefore, any
1827 // owned monitors at this point MUST be JNI-acquired monitors which are
1828 // pre-inflated and in the monitor cache.
1829 //
1830 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1831 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1832 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1833 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1834 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1835 }
1836
1837 // These things needs to be done while we are still a Java Thread. Make sure that thread
1838 // is in a consistent state, in case GC happens
1839 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1840
1841 if (active_handles() != NULL) {
1842 JNIHandleBlock* block = active_handles();
1843 set_active_handles(NULL);
1844 JNIHandleBlock::release_block(block);
1845 }
1846
1847 if (free_handle_block() != NULL) {
1848 JNIHandleBlock* block = free_handle_block();
1849 set_free_handle_block(NULL);
1850 JNIHandleBlock::release_block(block);
1851 }
1852
1853 // These have to be removed while this is still a valid thread.
1854 remove_stack_guard_pages();
1855
1856 if (UseTLAB) {
1857 tlab().make_parsable(true); // retire TLAB
1858 }
1859
1860 if (JvmtiEnv::environments_might_exist()) {
1861 JvmtiExport::cleanup_thread(this);
1862 }
1863
1864 // We must flush any deferred card marks before removing a thread from
1865 // the list of active threads.
1866 Universe::heap()->flush_deferred_store_barrier(this);
1867 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1868
1869 #if INCLUDE_ALL_GCS
1870 // We must flush the G1-related buffers before removing a thread
1871 // from the list of active threads. We must do this after any deferred
1872 // card marks have been flushed (above) so that any entries that are
1873 // added to the thread's dirty card queue as a result are not lost.
1874 if (UseG1GC) {
1875 flush_barrier_queues();
1876 }
1877 #endif // INCLUDE_ALL_GCS
1878
1879 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1880 Threads::remove(this);
1881 }
1882
1883 #if INCLUDE_ALL_GCS
1884 // Flush G1-related queues.
1885 void JavaThread::flush_barrier_queues() {
1886 satb_mark_queue().flush();
1887 dirty_card_queue().flush();
1888 }
1889
1890 void JavaThread::initialize_queues() {
1891 assert(!SafepointSynchronize::is_at_safepoint(),
1892 "we should not be at a safepoint");
1893
1894 ObjPtrQueue& satb_queue = satb_mark_queue();
1895 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1896 // The SATB queue should have been constructed with its active
1897 // field set to false.
1898 assert(!satb_queue.is_active(), "SATB queue should not be active");
1899 assert(satb_queue.is_empty(), "SATB queue should be empty");
1900 // If we are creating the thread during a marking cycle, we should
1901 // set the active field of the SATB queue to true.
1902 if (satb_queue_set.is_active()) {
1903 satb_queue.set_active(true);
1904 }
1905
1906 DirtyCardQueue& dirty_queue = dirty_card_queue();
1907 // The dirty card queue should have been constructed with its
1908 // active field set to true.
1909 assert(dirty_queue.is_active(), "dirty card queue should be active");
1910 }
1911 #endif // INCLUDE_ALL_GCS
1912
1913 void JavaThread::cleanup_failed_attach_current_thread() {
1914 if (get_thread_profiler() != NULL) {
1915 get_thread_profiler()->disengage();
1916 ResourceMark rm;
1917 get_thread_profiler()->print(get_thread_name());
1918 }
1919
1920 if (active_handles() != NULL) {
1921 JNIHandleBlock* block = active_handles();
1922 set_active_handles(NULL);
1923 JNIHandleBlock::release_block(block);
1924 }
1925
1926 if (free_handle_block() != NULL) {
1927 JNIHandleBlock* block = free_handle_block();
1928 set_free_handle_block(NULL);
1929 JNIHandleBlock::release_block(block);
1930 }
1931
1932 // These have to be removed while this is still a valid thread.
1933 remove_stack_guard_pages();
1934
1935 if (UseTLAB) {
1936 tlab().make_parsable(true); // retire TLAB, if any
1937 }
1938
1939 #if INCLUDE_ALL_GCS
1940 if (UseG1GC) {
1941 flush_barrier_queues();
1942 }
1943 #endif // INCLUDE_ALL_GCS
1944
1945 Threads::remove(this);
1946 delete this;
1947 }
1948
1949
1950
1951
1952 JavaThread* JavaThread::active() {
1953 Thread* thread = ThreadLocalStorage::thread();
1954 assert(thread != NULL, "just checking");
1955 if (thread->is_Java_thread()) {
1956 return (JavaThread*) thread;
1957 } else {
1958 assert(thread->is_VM_thread(), "this must be a vm thread");
1959 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1960 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1961 assert(ret->is_Java_thread(), "must be a Java thread");
1962 return ret;
1963 }
1964 }
1965
1966 bool JavaThread::is_lock_owned(address adr) const {
1967 if (Thread::is_lock_owned(adr)) return true;
1968
1969 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1970 if (chunk->contains(adr)) return true;
1971 }
1972
1973 return false;
1974 }
1975
1976
1977 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1978 chunk->set_next(monitor_chunks());
1979 set_monitor_chunks(chunk);
1980 }
1981
1982 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1983 guarantee(monitor_chunks() != NULL, "must be non empty");
1984 if (monitor_chunks() == chunk) {
1985 set_monitor_chunks(chunk->next());
1986 } else {
1987 MonitorChunk* prev = monitor_chunks();
1988 while (prev->next() != chunk) prev = prev->next();
1989 prev->set_next(chunk->next());
1990 }
1991 }
1992
1993 // JVM support.
1994
1995 // Note: this function shouldn't block if it's called in
1996 // _thread_in_native_trans state (such as from
1997 // check_special_condition_for_native_trans()).
1998 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1999
2000 if (has_last_Java_frame() && has_async_condition()) {
2001 // If we are at a polling page safepoint (not a poll return)
2002 // then we must defer async exception because live registers
2003 // will be clobbered by the exception path. Poll return is
2004 // ok because the call we a returning from already collides
2005 // with exception handling registers and so there is no issue.
2006 // (The exception handling path kills call result registers but
2007 // this is ok since the exception kills the result anyway).
2008
2009 if (is_at_poll_safepoint()) {
2010 // if the code we are returning to has deoptimized we must defer
2011 // the exception otherwise live registers get clobbered on the
2012 // exception path before deoptimization is able to retrieve them.
2013 //
2014 RegisterMap map(this, false);
2015 frame caller_fr = last_frame().sender(&map);
2016 assert(caller_fr.is_compiled_frame(), "what?");
2017 if (caller_fr.is_deoptimized_frame()) {
2018 if (TraceExceptions) {
2019 ResourceMark rm;
2020 tty->print_cr("deferred async exception at compiled safepoint");
2021 }
2022 return;
2023 }
2024 }
2025 }
2026
2027 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2028 if (condition == _no_async_condition) {
2029 // Conditions have changed since has_special_runtime_exit_condition()
2030 // was called:
2031 // - if we were here only because of an external suspend request,
2032 // then that was taken care of above (or cancelled) so we are done
2033 // - if we were here because of another async request, then it has
2034 // been cleared between the has_special_runtime_exit_condition()
2035 // and now so again we are done
2036 return;
2037 }
2038
2039 // Check for pending async. exception
2040 if (_pending_async_exception != NULL) {
2041 // Only overwrite an already pending exception, if it is not a threadDeath.
2042 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2043
2044 // We cannot call Exceptions::_throw(...) here because we cannot block
2045 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2046
2047 if (TraceExceptions) {
2048 ResourceMark rm;
2049 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2050 if (has_last_Java_frame()) {
2051 frame f = last_frame();
2052 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2053 }
2054 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2055 }
2056 _pending_async_exception = NULL;
2057 clear_has_async_exception();
2058 }
2059 }
2060
2061 if (check_unsafe_error &&
2062 condition == _async_unsafe_access_error && !has_pending_exception()) {
2063 condition = _no_async_condition; // done
2064 switch (thread_state()) {
2065 case _thread_in_vm:
2066 {
2067 JavaThread* THREAD = this;
2068 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2069 }
2070 case _thread_in_native:
2071 {
2072 ThreadInVMfromNative tiv(this);
2073 JavaThread* THREAD = this;
2074 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2075 }
2076 case _thread_in_Java:
2077 {
2078 ThreadInVMfromJava tiv(this);
2079 JavaThread* THREAD = this;
2080 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2081 }
2082 default:
2083 ShouldNotReachHere();
2084 }
2085 }
2086
2087 assert(condition == _no_async_condition || has_pending_exception() ||
2088 (!check_unsafe_error && condition == _async_unsafe_access_error),
2089 "must have handled the async condition, if no exception");
2090 }
2091
2092 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2093 //
2094 // Check for pending external suspend. Internal suspend requests do
2095 // not use handle_special_runtime_exit_condition().
2096 // If JNIEnv proxies are allowed, don't self-suspend if the target
2097 // thread is not the current thread. In older versions of jdbx, jdbx
2098 // threads could call into the VM with another thread's JNIEnv so we
2099 // can be here operating on behalf of a suspended thread (4432884).
2100 bool do_self_suspend = is_external_suspend_with_lock();
2101 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2102 //
2103 // Because thread is external suspended the safepoint code will count
2104 // thread as at a safepoint. This can be odd because we can be here
2105 // as _thread_in_Java which would normally transition to _thread_blocked
2106 // at a safepoint. We would like to mark the thread as _thread_blocked
2107 // before calling java_suspend_self like all other callers of it but
2108 // we must then observe proper safepoint protocol. (We can't leave
2109 // _thread_blocked with a safepoint in progress). However we can be
2110 // here as _thread_in_native_trans so we can't use a normal transition
2111 // constructor/destructor pair because they assert on that type of
2112 // transition. We could do something like:
2113 //
2114 // JavaThreadState state = thread_state();
2115 // set_thread_state(_thread_in_vm);
2116 // {
2117 // ThreadBlockInVM tbivm(this);
2118 // java_suspend_self()
2119 // }
2120 // set_thread_state(_thread_in_vm_trans);
2121 // if (safepoint) block;
2122 // set_thread_state(state);
2123 //
2124 // but that is pretty messy. Instead we just go with the way the
2125 // code has worked before and note that this is the only path to
2126 // java_suspend_self that doesn't put the thread in _thread_blocked
2127 // mode.
2128
2129 frame_anchor()->make_walkable(this);
2130 java_suspend_self();
2131
2132 // We might be here for reasons in addition to the self-suspend request
2133 // so check for other async requests.
2134 }
2135
2136 if (check_asyncs) {
2137 check_and_handle_async_exceptions();
2138 }
2139 }
2140
2141 void JavaThread::send_thread_stop(oop java_throwable) {
2142 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2143 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2144 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2145
2146 // Do not throw asynchronous exceptions against the compiler thread
2147 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2148 if (is_Compiler_thread()) return;
2149
2150 {
2151 // Actually throw the Throwable against the target Thread - however
2152 // only if there is no thread death exception installed already.
2153 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2154 // If the topmost frame is a runtime stub, then we are calling into
2155 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2156 // must deoptimize the caller before continuing, as the compiled exception handler table
2157 // may not be valid
2158 if (has_last_Java_frame()) {
2159 frame f = last_frame();
2160 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2161 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2162 RegisterMap reg_map(this, UseBiasedLocking);
2163 frame compiled_frame = f.sender(®_map);
2164 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2165 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2166 }
2167 }
2168 }
2169
2170 // Set async. pending exception in thread.
2171 set_pending_async_exception(java_throwable);
2172
2173 if (TraceExceptions) {
2174 ResourceMark rm;
2175 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2176 }
2177 // for AbortVMOnException flag
2178 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2179 }
2180 }
2181
2182
2183 // Interrupt thread so it will wake up from a potential wait()
2184 Thread::interrupt(this);
2185 }
2186
2187 // External suspension mechanism.
2188 //
2189 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2190 // to any VM_locks and it is at a transition
2191 // Self-suspension will happen on the transition out of the vm.
2192 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2193 //
2194 // Guarantees on return:
2195 // + Target thread will not execute any new bytecode (that's why we need to
2196 // force a safepoint)
2197 // + Target thread will not enter any new monitors
2198 //
2199 void JavaThread::java_suspend() {
2200 { MutexLocker mu(Threads_lock);
2201 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2202 return;
2203 }
2204 }
2205
2206 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2207 if (!is_external_suspend()) {
2208 // a racing resume has cancelled us; bail out now
2209 return;
2210 }
2211
2212 // suspend is done
2213 uint32_t debug_bits = 0;
2214 // Warning: is_ext_suspend_completed() may temporarily drop the
2215 // SR_lock to allow the thread to reach a stable thread state if
2216 // it is currently in a transient thread state.
2217 if (is_ext_suspend_completed(false /* !called_by_wait */,
2218 SuspendRetryDelay, &debug_bits) ) {
2219 return;
2220 }
2221 }
2222
2223 VM_ForceSafepoint vm_suspend;
2224 VMThread::execute(&vm_suspend);
2225 }
2226
2227 // Part II of external suspension.
2228 // A JavaThread self suspends when it detects a pending external suspend
2229 // request. This is usually on transitions. It is also done in places
2230 // where continuing to the next transition would surprise the caller,
2231 // e.g., monitor entry.
2232 //
2233 // Returns the number of times that the thread self-suspended.
2234 //
2235 // Note: DO NOT call java_suspend_self() when you just want to block current
2236 // thread. java_suspend_self() is the second stage of cooperative
2237 // suspension for external suspend requests and should only be used
2238 // to complete an external suspend request.
2239 //
2240 int JavaThread::java_suspend_self() {
2241 int ret = 0;
2242
2243 // we are in the process of exiting so don't suspend
2244 if (is_exiting()) {
2245 clear_external_suspend();
2246 return ret;
2247 }
2248
2249 assert(_anchor.walkable() ||
2250 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2251 "must have walkable stack");
2252
2253 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2254
2255 assert(!this->is_ext_suspended(),
2256 "a thread trying to self-suspend should not already be suspended");
2257
2258 if (this->is_suspend_equivalent()) {
2259 // If we are self-suspending as a result of the lifting of a
2260 // suspend equivalent condition, then the suspend_equivalent
2261 // flag is not cleared until we set the ext_suspended flag so
2262 // that wait_for_ext_suspend_completion() returns consistent
2263 // results.
2264 this->clear_suspend_equivalent();
2265 }
2266
2267 // A racing resume may have cancelled us before we grabbed SR_lock
2268 // above. Or another external suspend request could be waiting for us
2269 // by the time we return from SR_lock()->wait(). The thread
2270 // that requested the suspension may already be trying to walk our
2271 // stack and if we return now, we can change the stack out from under
2272 // it. This would be a "bad thing (TM)" and cause the stack walker
2273 // to crash. We stay self-suspended until there are no more pending
2274 // external suspend requests.
2275 while (is_external_suspend()) {
2276 ret++;
2277 this->set_ext_suspended();
2278
2279 // _ext_suspended flag is cleared by java_resume()
2280 while (is_ext_suspended()) {
2281 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2282 }
2283 }
2284
2285 return ret;
2286 }
2287
2288 #ifdef ASSERT
2289 // verify the JavaThread has not yet been published in the Threads::list, and
2290 // hence doesn't need protection from concurrent access at this stage
2291 void JavaThread::verify_not_published() {
2292 if (!Threads_lock->owned_by_self()) {
2293 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2294 assert(!Threads::includes(this),
2295 "java thread shouldn't have been published yet!");
2296 }
2297 else {
2298 assert(!Threads::includes(this),
2299 "java thread shouldn't have been published yet!");
2300 }
2301 }
2302 #endif
2303
2304 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2305 // progress or when _suspend_flags is non-zero.
2306 // Current thread needs to self-suspend if there is a suspend request and/or
2307 // block if a safepoint is in progress.
2308 // Async exception ISN'T checked.
2309 // Note only the ThreadInVMfromNative transition can call this function
2310 // directly and when thread state is _thread_in_native_trans
2311 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2312 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2313
2314 JavaThread *curJT = JavaThread::current();
2315 bool do_self_suspend = thread->is_external_suspend();
2316
2317 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2318
2319 // If JNIEnv proxies are allowed, don't self-suspend if the target
2320 // thread is not the current thread. In older versions of jdbx, jdbx
2321 // threads could call into the VM with another thread's JNIEnv so we
2322 // can be here operating on behalf of a suspended thread (4432884).
2323 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2324 JavaThreadState state = thread->thread_state();
2325
2326 // We mark this thread_blocked state as a suspend-equivalent so
2327 // that a caller to is_ext_suspend_completed() won't be confused.
2328 // The suspend-equivalent state is cleared by java_suspend_self().
2329 thread->set_suspend_equivalent();
2330
2331 // If the safepoint code sees the _thread_in_native_trans state, it will
2332 // wait until the thread changes to other thread state. There is no
2333 // guarantee on how soon we can obtain the SR_lock and complete the
2334 // self-suspend request. It would be a bad idea to let safepoint wait for
2335 // too long. Temporarily change the state to _thread_blocked to
2336 // let the VM thread know that this thread is ready for GC. The problem
2337 // of changing thread state is that safepoint could happen just after
2338 // java_suspend_self() returns after being resumed, and VM thread will
2339 // see the _thread_blocked state. We must check for safepoint
2340 // after restoring the state and make sure we won't leave while a safepoint
2341 // is in progress.
2342 thread->set_thread_state(_thread_blocked);
2343 thread->java_suspend_self();
2344 thread->set_thread_state(state);
2345 // Make sure new state is seen by VM thread
2346 if (os::is_MP()) {
2347 if (UseMembar) {
2348 // Force a fence between the write above and read below
2349 OrderAccess::fence();
2350 } else {
2351 // Must use this rather than serialization page in particular on Windows
2352 InterfaceSupport::serialize_memory(thread);
2353 }
2354 }
2355 }
2356
2357 if (SafepointSynchronize::do_call_back()) {
2358 // If we are safepointing, then block the caller which may not be
2359 // the same as the target thread (see above).
2360 SafepointSynchronize::block(curJT);
2361 }
2362
2363 if (thread->is_deopt_suspend()) {
2364 thread->clear_deopt_suspend();
2365 RegisterMap map(thread, false);
2366 frame f = thread->last_frame();
2367 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2368 f = f.sender(&map);
2369 }
2370 if (f.id() == thread->must_deopt_id()) {
2371 thread->clear_must_deopt_id();
2372 f.deoptimize(thread);
2373 } else {
2374 fatal("missed deoptimization!");
2375 }
2376 }
2377 }
2378
2379 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2380 // progress or when _suspend_flags is non-zero.
2381 // Current thread needs to self-suspend if there is a suspend request and/or
2382 // block if a safepoint is in progress.
2383 // Also check for pending async exception (not including unsafe access error).
2384 // Note only the native==>VM/Java barriers can call this function and when
2385 // thread state is _thread_in_native_trans.
2386 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2387 check_safepoint_and_suspend_for_native_trans(thread);
2388
2389 if (thread->has_async_exception()) {
2390 // We are in _thread_in_native_trans state, don't handle unsafe
2391 // access error since that may block.
2392 thread->check_and_handle_async_exceptions(false);
2393 }
2394 }
2395
2396 // This is a variant of the normal
2397 // check_special_condition_for_native_trans with slightly different
2398 // semantics for use by critical native wrappers. It does all the
2399 // normal checks but also performs the transition back into
2400 // thread_in_Java state. This is required so that critical natives
2401 // can potentially block and perform a GC if they are the last thread
2402 // exiting the GC_locker.
2403 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2404 check_special_condition_for_native_trans(thread);
2405
2406 // Finish the transition
2407 thread->set_thread_state(_thread_in_Java);
2408
2409 if (thread->do_critical_native_unlock()) {
2410 ThreadInVMfromJavaNoAsyncException tiv(thread);
2411 GC_locker::unlock_critical(thread);
2412 thread->clear_critical_native_unlock();
2413 }
2414 }
2415
2416 // We need to guarantee the Threads_lock here, since resumes are not
2417 // allowed during safepoint synchronization
2418 // Can only resume from an external suspension
2419 void JavaThread::java_resume() {
2420 assert_locked_or_safepoint(Threads_lock);
2421
2422 // Sanity check: thread is gone, has started exiting or the thread
2423 // was not externally suspended.
2424 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2425 return;
2426 }
2427
2428 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2429
2430 clear_external_suspend();
2431
2432 if (is_ext_suspended()) {
2433 clear_ext_suspended();
2434 SR_lock()->notify_all();
2435 }
2436 }
2437
2438 void JavaThread::create_stack_guard_pages() {
2439 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2440 address low_addr = stack_base() - stack_size();
2441 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2442
2443 int allocate = os::allocate_stack_guard_pages();
2444 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2445
2446 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2447 warning("Attempt to allocate stack guard pages failed.");
2448 return;
2449 }
2450
2451 if (os::guard_memory((char *) low_addr, len)) {
2452 _stack_guard_state = stack_guard_enabled;
2453 } else {
2454 warning("Attempt to protect stack guard pages failed.");
2455 if (os::uncommit_memory((char *) low_addr, len)) {
2456 warning("Attempt to deallocate stack guard pages failed.");
2457 }
2458 }
2459 }
2460
2461 void JavaThread::remove_stack_guard_pages() {
2462 assert(Thread::current() == this, "from different thread");
2463 if (_stack_guard_state == stack_guard_unused) return;
2464 address low_addr = stack_base() - stack_size();
2465 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2466
2467 if (os::allocate_stack_guard_pages()) {
2468 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2469 _stack_guard_state = stack_guard_unused;
2470 } else {
2471 warning("Attempt to deallocate stack guard pages failed.");
2472 }
2473 } else {
2474 if (_stack_guard_state == stack_guard_unused) return;
2475 if (os::unguard_memory((char *) low_addr, len)) {
2476 _stack_guard_state = stack_guard_unused;
2477 } else {
2478 warning("Attempt to unprotect stack guard pages failed.");
2479 }
2480 }
2481 }
2482
2483 void JavaThread::enable_stack_yellow_zone() {
2484 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2485 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2486
2487 // The base notation is from the stacks point of view, growing downward.
2488 // We need to adjust it to work correctly with guard_memory()
2489 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2490
2491 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2492 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2493
2494 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2495 _stack_guard_state = stack_guard_enabled;
2496 } else {
2497 warning("Attempt to guard stack yellow zone failed.");
2498 }
2499 enable_register_stack_guard();
2500 }
2501
2502 void JavaThread::disable_stack_yellow_zone() {
2503 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2504 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2505
2506 // Simply return if called for a thread that does not use guard pages.
2507 if (_stack_guard_state == stack_guard_unused) return;
2508
2509 // The base notation is from the stacks point of view, growing downward.
2510 // We need to adjust it to work correctly with guard_memory()
2511 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2512
2513 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2514 _stack_guard_state = stack_guard_yellow_disabled;
2515 } else {
2516 warning("Attempt to unguard stack yellow zone failed.");
2517 }
2518 disable_register_stack_guard();
2519 }
2520
2521 void JavaThread::enable_stack_red_zone() {
2522 // The base notation is from the stacks point of view, growing downward.
2523 // We need to adjust it to work correctly with guard_memory()
2524 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2525 address base = stack_red_zone_base() - stack_red_zone_size();
2526
2527 guarantee(base < stack_base(), "Error calculating stack red zone");
2528 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2529
2530 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2531 warning("Attempt to guard stack red zone failed.");
2532 }
2533 }
2534
2535 void JavaThread::disable_stack_red_zone() {
2536 // The base notation is from the stacks point of view, growing downward.
2537 // We need to adjust it to work correctly with guard_memory()
2538 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2539 address base = stack_red_zone_base() - stack_red_zone_size();
2540 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2541 warning("Attempt to unguard stack red zone failed.");
2542 }
2543 }
2544
2545 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2546 // ignore is there is no stack
2547 if (!has_last_Java_frame()) return;
2548 // traverse the stack frames. Starts from top frame.
2549 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2550 frame* fr = fst.current();
2551 f(fr, fst.register_map());
2552 }
2553 }
2554
2555
2556 #ifndef PRODUCT
2557 // Deoptimization
2558 // Function for testing deoptimization
2559 void JavaThread::deoptimize() {
2560 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2561 StackFrameStream fst(this, UseBiasedLocking);
2562 bool deopt = false; // Dump stack only if a deopt actually happens.
2563 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2564 // Iterate over all frames in the thread and deoptimize
2565 for (; !fst.is_done(); fst.next()) {
2566 if (fst.current()->can_be_deoptimized()) {
2567
2568 if (only_at) {
2569 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2570 // consists of comma or carriage return separated numbers so
2571 // search for the current bci in that string.
2572 address pc = fst.current()->pc();
2573 nmethod* nm = (nmethod*) fst.current()->cb();
2574 ScopeDesc* sd = nm->scope_desc_at( pc);
2575 char buffer[8];
2576 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2577 size_t len = strlen(buffer);
2578 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2579 while (found != NULL) {
2580 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2581 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2582 // Check that the bci found is bracketed by terminators.
2583 break;
2584 }
2585 found = strstr(found + 1, buffer);
2586 }
2587 if (!found) {
2588 continue;
2589 }
2590 }
2591
2592 if (DebugDeoptimization && !deopt) {
2593 deopt = true; // One-time only print before deopt
2594 tty->print_cr("[BEFORE Deoptimization]");
2595 trace_frames();
2596 trace_stack();
2597 }
2598 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2599 }
2600 }
2601
2602 if (DebugDeoptimization && deopt) {
2603 tty->print_cr("[AFTER Deoptimization]");
2604 trace_frames();
2605 }
2606 }
2607
2608
2609 // Make zombies
2610 void JavaThread::make_zombies() {
2611 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2612 if (fst.current()->can_be_deoptimized()) {
2613 // it is a Java nmethod
2614 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2615 nm->make_not_entrant();
2616 }
2617 }
2618 }
2619 #endif // PRODUCT
2620
2621
2622 void JavaThread::deoptimized_wrt_marked_nmethods() {
2623 if (!has_last_Java_frame()) return;
2624 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2625 StackFrameStream fst(this, UseBiasedLocking);
2626 for (; !fst.is_done(); fst.next()) {
2627 if (fst.current()->should_be_deoptimized()) {
2628 if (LogCompilation && xtty != NULL) {
2629 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2630 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2631 this->name(), nm != NULL ? nm->compile_id() : -1);
2632 }
2633
2634 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2635 }
2636 }
2637 }
2638
2639
2640 // GC support
2641 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2642
2643 void JavaThread::gc_epilogue() {
2644 frames_do(frame_gc_epilogue);
2645 }
2646
2647
2648 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2649
2650 void JavaThread::gc_prologue() {
2651 frames_do(frame_gc_prologue);
2652 }
2653
2654 // If the caller is a NamedThread, then remember, in the current scope,
2655 // the given JavaThread in its _processed_thread field.
2656 class RememberProcessedThread: public StackObj {
2657 NamedThread* _cur_thr;
2658 public:
2659 RememberProcessedThread(JavaThread* jthr) {
2660 Thread* thread = Thread::current();
2661 if (thread->is_Named_thread()) {
2662 _cur_thr = (NamedThread *)thread;
2663 _cur_thr->set_processed_thread(jthr);
2664 } else {
2665 _cur_thr = NULL;
2666 }
2667 }
2668
2669 ~RememberProcessedThread() {
2670 if (_cur_thr) {
2671 _cur_thr->set_processed_thread(NULL);
2672 }
2673 }
2674 };
2675
2676 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2677 // Verify that the deferred card marks have been flushed.
2678 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2679
2680 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2681 // since there may be more than one thread using each ThreadProfiler.
2682
2683 // Traverse the GCHandles
2684 Thread::oops_do(f, cld_f, cf);
2685
2686 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2687 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2688
2689 if (has_last_Java_frame()) {
2690 // Record JavaThread to GC thread
2691 RememberProcessedThread rpt(this);
2692
2693 // Traverse the privileged stack
2694 if (_privileged_stack_top != NULL) {
2695 _privileged_stack_top->oops_do(f);
2696 }
2697
2698 // traverse the registered growable array
2699 if (_array_for_gc != NULL) {
2700 for (int index = 0; index < _array_for_gc->length(); index++) {
2701 f->do_oop(_array_for_gc->adr_at(index));
2702 }
2703 }
2704
2705 // Traverse the monitor chunks
2706 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2707 chunk->oops_do(f);
2708 }
2709
2710 // Traverse the execution stack
2711 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2712 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2713 }
2714 }
2715
2716 // callee_target is never live across a gc point so NULL it here should
2717 // it still contain a methdOop.
2718
2719 set_callee_target(NULL);
2720
2721 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2722 // If we have deferred set_locals there might be oops waiting to be
2723 // written
2724 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2725 if (list != NULL) {
2726 for (int i = 0; i < list->length(); i++) {
2727 list->at(i)->oops_do(f);
2728 }
2729 }
2730
2731 // Traverse instance variables at the end since the GC may be moving things
2732 // around using this function
2733 f->do_oop((oop*) &_threadObj);
2734 f->do_oop((oop*) &_vm_result);
2735 f->do_oop((oop*) &_exception_oop);
2736 f->do_oop((oop*) &_pending_async_exception);
2737
2738 if (jvmti_thread_state() != NULL) {
2739 jvmti_thread_state()->oops_do(f);
2740 }
2741 }
2742
2743 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2744 Thread::nmethods_do(cf); // (super method is a no-op)
2745
2746 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2747 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2748
2749 if (has_last_Java_frame()) {
2750 // Traverse the execution stack
2751 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2752 fst.current()->nmethods_do(cf);
2753 }
2754 }
2755 }
2756
2757 void JavaThread::metadata_do(void f(Metadata*)) {
2758 Thread::metadata_do(f);
2759 if (has_last_Java_frame()) {
2760 // Traverse the execution stack to call f() on the methods in the stack
2761 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2762 fst.current()->metadata_do(f);
2763 }
2764 } else if (is_Compiler_thread()) {
2765 // need to walk ciMetadata in current compile tasks to keep alive.
2766 CompilerThread* ct = (CompilerThread*)this;
2767 if (ct->env() != NULL) {
2768 ct->env()->metadata_do(f);
2769 }
2770 }
2771 }
2772
2773 // Printing
2774 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2775 switch (_thread_state) {
2776 case _thread_uninitialized: return "_thread_uninitialized";
2777 case _thread_new: return "_thread_new";
2778 case _thread_new_trans: return "_thread_new_trans";
2779 case _thread_in_native: return "_thread_in_native";
2780 case _thread_in_native_trans: return "_thread_in_native_trans";
2781 case _thread_in_vm: return "_thread_in_vm";
2782 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2783 case _thread_in_Java: return "_thread_in_Java";
2784 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2785 case _thread_blocked: return "_thread_blocked";
2786 case _thread_blocked_trans: return "_thread_blocked_trans";
2787 default: return "unknown thread state";
2788 }
2789 }
2790
2791 #ifndef PRODUCT
2792 void JavaThread::print_thread_state_on(outputStream *st) const {
2793 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2794 };
2795 void JavaThread::print_thread_state() const {
2796 print_thread_state_on(tty);
2797 };
2798 #endif // PRODUCT
2799
2800 // Called by Threads::print() for VM_PrintThreads operation
2801 void JavaThread::print_on(outputStream *st) const {
2802 st->print("\"%s\" ", get_thread_name());
2803 oop thread_oop = threadObj();
2804 if (thread_oop != NULL) {
2805 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2806 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2807 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2808 }
2809 Thread::print_on(st);
2810 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2811 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2812 if (thread_oop != NULL) {
2813 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2814 }
2815 #ifndef PRODUCT
2816 print_thread_state_on(st);
2817 _safepoint_state->print_on(st);
2818 #endif // PRODUCT
2819 }
2820
2821 // Called by fatal error handler. The difference between this and
2822 // JavaThread::print() is that we can't grab lock or allocate memory.
2823 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2824 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2825 oop thread_obj = threadObj();
2826 if (thread_obj != NULL) {
2827 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2828 }
2829 st->print(" [");
2830 st->print("%s", _get_thread_state_name(_thread_state));
2831 if (osthread()) {
2832 st->print(", id=%d", osthread()->thread_id());
2833 }
2834 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2835 _stack_base - _stack_size, _stack_base);
2836 st->print("]");
2837 return;
2838 }
2839
2840 // Verification
2841
2842 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2843
2844 void JavaThread::verify() {
2845 // Verify oops in the thread.
2846 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2847
2848 // Verify the stack frames.
2849 frames_do(frame_verify);
2850 }
2851
2852 // CR 6300358 (sub-CR 2137150)
2853 // Most callers of this method assume that it can't return NULL but a
2854 // thread may not have a name whilst it is in the process of attaching to
2855 // the VM - see CR 6412693, and there are places where a JavaThread can be
2856 // seen prior to having it's threadObj set (eg JNI attaching threads and
2857 // if vm exit occurs during initialization). These cases can all be accounted
2858 // for such that this method never returns NULL.
2859 const char* JavaThread::get_thread_name() const {
2860 #ifdef ASSERT
2861 // early safepoints can hit while current thread does not yet have TLS
2862 if (!SafepointSynchronize::is_at_safepoint()) {
2863 Thread *cur = Thread::current();
2864 if (!(cur->is_Java_thread() && cur == this)) {
2865 // Current JavaThreads are allowed to get their own name without
2866 // the Threads_lock.
2867 assert_locked_or_safepoint(Threads_lock);
2868 }
2869 }
2870 #endif // ASSERT
2871 return get_thread_name_string();
2872 }
2873
2874 // Returns a non-NULL representation of this thread's name, or a suitable
2875 // descriptive string if there is no set name
2876 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2877 const char* name_str;
2878 oop thread_obj = threadObj();
2879 if (thread_obj != NULL) {
2880 typeArrayOop name = java_lang_Thread::name(thread_obj);
2881 if (name != NULL) {
2882 if (buf == NULL) {
2883 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2884 }
2885 else {
2886 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2887 }
2888 }
2889 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2890 name_str = "<no-name - thread is attaching>";
2891 }
2892 else {
2893 name_str = Thread::name();
2894 }
2895 }
2896 else {
2897 name_str = Thread::name();
2898 }
2899 assert(name_str != NULL, "unexpected NULL thread name");
2900 return name_str;
2901 }
2902
2903
2904 const char* JavaThread::get_threadgroup_name() const {
2905 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2906 oop thread_obj = threadObj();
2907 if (thread_obj != NULL) {
2908 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2909 if (thread_group != NULL) {
2910 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2911 // ThreadGroup.name can be null
2912 if (name != NULL) {
2913 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2914 return str;
2915 }
2916 }
2917 }
2918 return NULL;
2919 }
2920
2921 const char* JavaThread::get_parent_name() const {
2922 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2923 oop thread_obj = threadObj();
2924 if (thread_obj != NULL) {
2925 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2926 if (thread_group != NULL) {
2927 oop parent = java_lang_ThreadGroup::parent(thread_group);
2928 if (parent != NULL) {
2929 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2930 // ThreadGroup.name can be null
2931 if (name != NULL) {
2932 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2933 return str;
2934 }
2935 }
2936 }
2937 }
2938 return NULL;
2939 }
2940
2941 ThreadPriority JavaThread::java_priority() const {
2942 oop thr_oop = threadObj();
2943 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2944 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2945 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2946 return priority;
2947 }
2948
2949 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2950
2951 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2952 // Link Java Thread object <-> C++ Thread
2953
2954 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2955 // and put it into a new Handle. The Handle "thread_oop" can then
2956 // be used to pass the C++ thread object to other methods.
2957
2958 // Set the Java level thread object (jthread) field of the
2959 // new thread (a JavaThread *) to C++ thread object using the
2960 // "thread_oop" handle.
2961
2962 // Set the thread field (a JavaThread *) of the
2963 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2964
2965 Handle thread_oop(Thread::current(),
2966 JNIHandles::resolve_non_null(jni_thread));
2967 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2968 "must be initialized");
2969 set_threadObj(thread_oop());
2970 java_lang_Thread::set_thread(thread_oop(), this);
2971
2972 if (prio == NoPriority) {
2973 prio = java_lang_Thread::priority(thread_oop());
2974 assert(prio != NoPriority, "A valid priority should be present");
2975 }
2976
2977 // Push the Java priority down to the native thread; needs Threads_lock
2978 Thread::set_priority(this, prio);
2979
2980 // Add the new thread to the Threads list and set it in motion.
2981 // We must have threads lock in order to call Threads::add.
2982 // It is crucial that we do not block before the thread is
2983 // added to the Threads list for if a GC happens, then the java_thread oop
2984 // will not be visited by GC.
2985 Threads::add(this);
2986 }
2987
2988 oop JavaThread::current_park_blocker() {
2989 // Support for JSR-166 locks
2990 oop thread_oop = threadObj();
2991 if (thread_oop != NULL &&
2992 JDK_Version::current().supports_thread_park_blocker()) {
2993 return java_lang_Thread::park_blocker(thread_oop);
2994 }
2995 return NULL;
2996 }
2997
2998
2999 void JavaThread::print_stack_on(outputStream* st) {
3000 if (!has_last_Java_frame()) return;
3001 ResourceMark rm;
3002 HandleMark hm;
3003
3004 RegisterMap reg_map(this);
3005 vframe* start_vf = last_java_vframe(®_map);
3006 int count = 0;
3007 for (vframe* f = start_vf; f; f = f->sender()) {
3008 if (f->is_java_frame()) {
3009 javaVFrame* jvf = javaVFrame::cast(f);
3010 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3011
3012 // Print out lock information
3013 if (JavaMonitorsInStackTrace) {
3014 jvf->print_lock_info_on(st, count);
3015 }
3016 } else {
3017 // Ignore non-Java frames
3018 }
3019
3020 // Bail-out case for too deep stacks
3021 count++;
3022 if (MaxJavaStackTraceDepth == count) return;
3023 }
3024 }
3025
3026
3027 // JVMTI PopFrame support
3028 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3029 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3030 if (in_bytes(size_in_bytes) != 0) {
3031 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3032 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3033 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3034 }
3035 }
3036
3037 void* JavaThread::popframe_preserved_args() {
3038 return _popframe_preserved_args;
3039 }
3040
3041 ByteSize JavaThread::popframe_preserved_args_size() {
3042 return in_ByteSize(_popframe_preserved_args_size);
3043 }
3044
3045 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3046 int sz = in_bytes(popframe_preserved_args_size());
3047 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3048 return in_WordSize(sz / wordSize);
3049 }
3050
3051 void JavaThread::popframe_free_preserved_args() {
3052 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3053 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3054 _popframe_preserved_args = NULL;
3055 _popframe_preserved_args_size = 0;
3056 }
3057
3058 #ifndef PRODUCT
3059
3060 void JavaThread::trace_frames() {
3061 tty->print_cr("[Describe stack]");
3062 int frame_no = 1;
3063 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3064 tty->print(" %d. ", frame_no++);
3065 fst.current()->print_value_on(tty, this);
3066 tty->cr();
3067 }
3068 }
3069
3070 class PrintAndVerifyOopClosure: public OopClosure {
3071 protected:
3072 template <class T> inline void do_oop_work(T* p) {
3073 oop obj = oopDesc::load_decode_heap_oop(p);
3074 if (obj == NULL) return;
3075 tty->print(INTPTR_FORMAT ": ", p);
3076 if (obj->is_oop_or_null()) {
3077 if (obj->is_objArray()) {
3078 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3079 } else {
3080 obj->print();
3081 }
3082 } else {
3083 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3084 }
3085 tty->cr();
3086 }
3087 public:
3088 virtual void do_oop(oop* p) { do_oop_work(p); }
3089 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3090 };
3091
3092
3093 static void oops_print(frame* f, const RegisterMap *map) {
3094 PrintAndVerifyOopClosure print;
3095 f->print_value();
3096 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3097 }
3098
3099 // Print our all the locations that contain oops and whether they are
3100 // valid or not. This useful when trying to find the oldest frame
3101 // where an oop has gone bad since the frame walk is from youngest to
3102 // oldest.
3103 void JavaThread::trace_oops() {
3104 tty->print_cr("[Trace oops]");
3105 frames_do(oops_print);
3106 }
3107
3108
3109 #ifdef ASSERT
3110 // Print or validate the layout of stack frames
3111 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3112 ResourceMark rm;
3113 PRESERVE_EXCEPTION_MARK;
3114 FrameValues values;
3115 int frame_no = 0;
3116 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3117 fst.current()->describe(values, ++frame_no);
3118 if (depth == frame_no) break;
3119 }
3120 if (validate_only) {
3121 values.validate();
3122 } else {
3123 tty->print_cr("[Describe stack layout]");
3124 values.print(this);
3125 }
3126 }
3127 #endif
3128
3129 void JavaThread::trace_stack_from(vframe* start_vf) {
3130 ResourceMark rm;
3131 int vframe_no = 1;
3132 for (vframe* f = start_vf; f; f = f->sender()) {
3133 if (f->is_java_frame()) {
3134 javaVFrame::cast(f)->print_activation(vframe_no++);
3135 } else {
3136 f->print();
3137 }
3138 if (vframe_no > StackPrintLimit) {
3139 tty->print_cr("...<more frames>...");
3140 return;
3141 }
3142 }
3143 }
3144
3145
3146 void JavaThread::trace_stack() {
3147 if (!has_last_Java_frame()) return;
3148 ResourceMark rm;
3149 HandleMark hm;
3150 RegisterMap reg_map(this);
3151 trace_stack_from(last_java_vframe(®_map));
3152 }
3153
3154
3155 #endif // PRODUCT
3156
3157
3158 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3159 assert(reg_map != NULL, "a map must be given");
3160 frame f = last_frame();
3161 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3162 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3163 }
3164 return NULL;
3165 }
3166
3167
3168 Klass* JavaThread::security_get_caller_class(int depth) {
3169 vframeStream vfst(this);
3170 vfst.security_get_caller_frame(depth);
3171 if (!vfst.at_end()) {
3172 return vfst.method()->method_holder();
3173 }
3174 return NULL;
3175 }
3176
3177 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3178 assert(thread->is_Compiler_thread(), "must be compiler thread");
3179 CompileBroker::compiler_thread_loop();
3180 }
3181
3182 // Create a CompilerThread
3183 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3184 : JavaThread(&compiler_thread_entry) {
3185 _env = NULL;
3186 _log = NULL;
3187 _task = NULL;
3188 _queue = queue;
3189 _counters = counters;
3190 _buffer_blob = NULL;
3191 _scanned_nmethod = NULL;
3192 _compiler = NULL;
3193
3194 #ifndef PRODUCT
3195 _ideal_graph_printer = NULL;
3196 #endif
3197 }
3198
3199 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3200 JavaThread::oops_do(f, cld_f, cf);
3201 if (_scanned_nmethod != NULL && cf != NULL) {
3202 // Safepoints can occur when the sweeper is scanning an nmethod so
3203 // process it here to make sure it isn't unloaded in the middle of
3204 // a scan.
3205 cf->do_code_blob(_scanned_nmethod);
3206 }
3207 }
3208
3209
3210 // ======= Threads ========
3211
3212 // The Threads class links together all active threads, and provides
3213 // operations over all threads. It is protected by its own Mutex
3214 // lock, which is also used in other contexts to protect thread
3215 // operations from having the thread being operated on from exiting
3216 // and going away unexpectedly (e.g., safepoint synchronization)
3217
3218 JavaThread* Threads::_thread_list = NULL;
3219 int Threads::_number_of_threads = 0;
3220 int Threads::_number_of_non_daemon_threads = 0;
3221 int Threads::_return_code = 0;
3222 size_t JavaThread::_stack_size_at_create = 0;
3223 #ifdef ASSERT
3224 bool Threads::_vm_complete = false;
3225 #endif
3226
3227 // All JavaThreads
3228 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3229
3230 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3231 void Threads::threads_do(ThreadClosure* tc) {
3232 assert_locked_or_safepoint(Threads_lock);
3233 // ALL_JAVA_THREADS iterates through all JavaThreads
3234 ALL_JAVA_THREADS(p) {
3235 tc->do_thread(p);
3236 }
3237 // Someday we could have a table or list of all non-JavaThreads.
3238 // For now, just manually iterate through them.
3239 tc->do_thread(VMThread::vm_thread());
3240 Universe::heap()->gc_threads_do(tc);
3241 WatcherThread *wt = WatcherThread::watcher_thread();
3242 // Strictly speaking, the following NULL check isn't sufficient to make sure
3243 // the data for WatcherThread is still valid upon being examined. However,
3244 // considering that WatchThread terminates when the VM is on the way to
3245 // exit at safepoint, the chance of the above is extremely small. The right
3246 // way to prevent termination of WatcherThread would be to acquire
3247 // Terminator_lock, but we can't do that without violating the lock rank
3248 // checking in some cases.
3249 if (wt != NULL)
3250 tc->do_thread(wt);
3251
3252 // If CompilerThreads ever become non-JavaThreads, add them here
3253 }
3254
3255
3256 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3257 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3258
3259 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3260 create_vm_init_libraries();
3261 }
3262
3263 initialize_class(vmSymbols::java_lang_String(), CHECK);
3264
3265 // Initialize java_lang.System (needed before creating the thread)
3266 initialize_class(vmSymbols::java_lang_System(), CHECK);
3267 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3268 Handle thread_group = create_initial_thread_group(CHECK);
3269 Universe::set_main_thread_group(thread_group());
3270 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3271 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3272 main_thread->set_threadObj(thread_object);
3273 // Set thread status to running since main thread has
3274 // been started and running.
3275 java_lang_Thread::set_thread_status(thread_object,
3276 java_lang_Thread::RUNNABLE);
3277
3278 // The VM creates & returns objects of this class. Make sure it's initialized.
3279 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3280
3281 // The VM preresolves methods to these classes. Make sure that they get initialized
3282 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3283 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3284 call_initializeSystemClass(CHECK);
3285
3286 // get the Java runtime name after java.lang.System is initialized
3287 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3288 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3289
3290 // an instance of OutOfMemory exception has been allocated earlier
3291 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3292 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3293 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3294 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3295 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3296 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3297 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3298 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3299 }
3300
3301 void Threads::initialize_jsr292_core_classes(TRAPS) {
3302 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3303 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3304 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3305 }
3306
3307 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3308
3309 extern void JDK_Version_init();
3310
3311 // Check version
3312 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3313
3314 // Initialize the output stream module
3315 ostream_init();
3316
3317 // Process java launcher properties.
3318 Arguments::process_sun_java_launcher_properties(args);
3319
3320 // Initialize the os module before using TLS
3321 os::init();
3322
3323 // Initialize system properties.
3324 Arguments::init_system_properties();
3325
3326 // So that JDK version can be used as a discriminator when parsing arguments
3327 JDK_Version_init();
3328
3329 // Update/Initialize System properties after JDK version number is known
3330 Arguments::init_version_specific_system_properties();
3331
3332 // Parse arguments
3333 jint parse_result = Arguments::parse(args);
3334 if (parse_result != JNI_OK) return parse_result;
3335
3336 os::init_before_ergo();
3337
3338 jint ergo_result = Arguments::apply_ergo();
3339 if (ergo_result != JNI_OK) return ergo_result;
3340
3341 if (PauseAtStartup) {
3342 os::pause();
3343 }
3344
3345 HOTSPOT_VM_INIT_BEGIN();
3346
3347 // Record VM creation timing statistics
3348 TraceVmCreationTime create_vm_timer;
3349 create_vm_timer.start();
3350
3351 // Timing (must come after argument parsing)
3352 TraceTime timer("Create VM", TraceStartupTime);
3353
3354 // Initialize the os module after parsing the args
3355 jint os_init_2_result = os::init_2();
3356 if (os_init_2_result != JNI_OK) return os_init_2_result;
3357
3358 jint adjust_after_os_result = Arguments::adjust_after_os();
3359 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3360
3361 // initialize TLS
3362 ThreadLocalStorage::init();
3363
3364 // Bootstrap native memory tracking, so it can start recording memory
3365 // activities before worker thread is started. This is the first phase
3366 // of bootstrapping, VM is currently running in single-thread mode.
3367 MemTracker::bootstrap_single_thread();
3368
3369 // Initialize output stream logging
3370 ostream_init_log();
3371
3372 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3373 // Must be before create_vm_init_agents()
3374 if (Arguments::init_libraries_at_startup()) {
3375 convert_vm_init_libraries_to_agents();
3376 }
3377
3378 // Launch -agentlib/-agentpath and converted -Xrun agents
3379 if (Arguments::init_agents_at_startup()) {
3380 create_vm_init_agents();
3381 }
3382
3383 // Initialize Threads state
3384 _thread_list = NULL;
3385 _number_of_threads = 0;
3386 _number_of_non_daemon_threads = 0;
3387
3388 // Initialize global data structures and create system classes in heap
3389 vm_init_globals();
3390
3391 // Attach the main thread to this os thread
3392 JavaThread* main_thread = new JavaThread();
3393 main_thread->set_thread_state(_thread_in_vm);
3394 // must do this before set_active_handles and initialize_thread_local_storage
3395 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3396 // change the stack size recorded here to one based on the java thread
3397 // stacksize. This adjusted size is what is used to figure the placement
3398 // of the guard pages.
3399 main_thread->record_stack_base_and_size();
3400 main_thread->initialize_thread_local_storage();
3401
3402 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3403
3404 if (!main_thread->set_as_starting_thread()) {
3405 vm_shutdown_during_initialization(
3406 "Failed necessary internal allocation. Out of swap space");
3407 delete main_thread;
3408 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3409 return JNI_ENOMEM;
3410 }
3411
3412 // Enable guard page *after* os::create_main_thread(), otherwise it would
3413 // crash Linux VM, see notes in os_linux.cpp.
3414 main_thread->create_stack_guard_pages();
3415
3416 // Initialize Java-Level synchronization subsystem
3417 ObjectMonitor::Initialize();
3418
3419 // Second phase of bootstrapping, VM is about entering multi-thread mode
3420 MemTracker::bootstrap_multi_thread();
3421
3422 // Initialize global modules
3423 jint status = init_globals();
3424 if (status != JNI_OK) {
3425 delete main_thread;
3426 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3427 return status;
3428 }
3429
3430 // Should be done after the heap is fully created
3431 main_thread->cache_global_variables();
3432
3433 HandleMark hm;
3434
3435 { MutexLocker mu(Threads_lock);
3436 Threads::add(main_thread);
3437 }
3438
3439 // Any JVMTI raw monitors entered in onload will transition into
3440 // real raw monitor. VM is setup enough here for raw monitor enter.
3441 JvmtiExport::transition_pending_onload_raw_monitors();
3442
3443 // Fully start NMT
3444 MemTracker::start();
3445
3446 // Create the VMThread
3447 { TraceTime timer("Start VMThread", TraceStartupTime);
3448 VMThread::create();
3449 Thread* vmthread = VMThread::vm_thread();
3450
3451 if (!os::create_thread(vmthread, os::vm_thread))
3452 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3453
3454 // Wait for the VM thread to become ready, and VMThread::run to initialize
3455 // Monitors can have spurious returns, must always check another state flag
3456 {
3457 MutexLocker ml(Notify_lock);
3458 os::start_thread(vmthread);
3459 while (vmthread->active_handles() == NULL) {
3460 Notify_lock->wait();
3461 }
3462 }
3463 }
3464
3465 assert(Universe::is_fully_initialized(), "not initialized");
3466 if (VerifyDuringStartup) {
3467 // Make sure we're starting with a clean slate.
3468 VM_Verify verify_op;
3469 VMThread::execute(&verify_op);
3470 }
3471
3472 Thread* THREAD = Thread::current();
3473
3474 // At this point, the Universe is initialized, but we have not executed
3475 // any byte code. Now is a good time (the only time) to dump out the
3476 // internal state of the JVM for sharing.
3477 if (DumpSharedSpaces) {
3478 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3479 ShouldNotReachHere();
3480 }
3481
3482 // Always call even when there are not JVMTI environments yet, since environments
3483 // may be attached late and JVMTI must track phases of VM execution
3484 JvmtiExport::enter_start_phase();
3485
3486 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3487 JvmtiExport::post_vm_start();
3488
3489 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3490
3491 // We need this for ClassDataSharing - the initial vm.info property is set
3492 // with the default value of CDS "sharing" which may be reset through
3493 // command line options.
3494 reset_vm_info_property(CHECK_JNI_ERR);
3495
3496 quicken_jni_functions();
3497
3498 // Must be run after init_ft which initializes ft_enabled
3499 if (TRACE_INITIALIZE() != JNI_OK) {
3500 vm_exit_during_initialization("Failed to initialize tracing backend");
3501 }
3502
3503 // Set flag that basic initialization has completed. Used by exceptions and various
3504 // debug stuff, that does not work until all basic classes have been initialized.
3505 set_init_completed();
3506
3507 Metaspace::post_initialize();
3508
3509 HOTSPOT_VM_INIT_END();
3510
3511 // record VM initialization completion time
3512 #if INCLUDE_MANAGEMENT
3513 Management::record_vm_init_completed();
3514 #endif // INCLUDE_MANAGEMENT
3515
3516 // Compute system loader. Note that this has to occur after set_init_completed, since
3517 // valid exceptions may be thrown in the process.
3518 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3519 // set_init_completed has just been called, causing exceptions not to be shortcut
3520 // anymore. We call vm_exit_during_initialization directly instead.
3521 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3522
3523 #if INCLUDE_ALL_GCS
3524 // Support for ConcurrentMarkSweep. This should be cleaned up
3525 // and better encapsulated. The ugly nested if test would go away
3526 // once things are properly refactored. XXX YSR
3527 if (UseConcMarkSweepGC || UseG1GC) {
3528 if (UseConcMarkSweepGC) {
3529 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3530 } else {
3531 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3532 }
3533 }
3534 #endif // INCLUDE_ALL_GCS
3535
3536 // Always call even when there are not JVMTI environments yet, since environments
3537 // may be attached late and JVMTI must track phases of VM execution
3538 JvmtiExport::enter_live_phase();
3539
3540 // Signal Dispatcher needs to be started before VMInit event is posted
3541 os::signal_init();
3542
3543 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3544 if (!DisableAttachMechanism) {
3545 AttachListener::vm_start();
3546 if (StartAttachListener || AttachListener::init_at_startup()) {
3547 AttachListener::init();
3548 }
3549 }
3550
3551 // Launch -Xrun agents
3552 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3553 // back-end can launch with -Xdebug -Xrunjdwp.
3554 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3555 create_vm_init_libraries();
3556 }
3557
3558 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3559 JvmtiExport::post_vm_initialized();
3560
3561 if (TRACE_START() != JNI_OK) {
3562 vm_exit_during_initialization("Failed to start tracing backend.");
3563 }
3564
3565 if (CleanChunkPoolAsync) {
3566 Chunk::start_chunk_pool_cleaner_task();
3567 }
3568
3569 // initialize compiler(s)
3570 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3571 CompileBroker::compilation_init();
3572 #endif
3573
3574 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3575 // It is done after compilers are initialized, because otherwise compilations of
3576 // signature polymorphic MH intrinsics can be missed
3577 // (see SystemDictionary::find_method_handle_intrinsic).
3578 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3579
3580 #if INCLUDE_MANAGEMENT
3581 Management::initialize(THREAD);
3582
3583 if (HAS_PENDING_EXCEPTION) {
3584 // management agent fails to start possibly due to
3585 // configuration problem and is responsible for printing
3586 // stack trace if appropriate. Simply exit VM.
3587 vm_exit(1);
3588 }
3589 #endif // INCLUDE_MANAGEMENT
3590
3591 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3592 if (MemProfiling) MemProfiler::engage();
3593 StatSampler::engage();
3594 if (CheckJNICalls) JniPeriodicChecker::engage();
3595
3596 BiasedLocking::init();
3597
3598 #if INCLUDE_RTM_OPT
3599 RTMLockingCounters::init();
3600 #endif
3601
3602 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3603 call_postVMInitHook(THREAD);
3604 // The Java side of PostVMInitHook.run must deal with all
3605 // exceptions and provide means of diagnosis.
3606 if (HAS_PENDING_EXCEPTION) {
3607 CLEAR_PENDING_EXCEPTION;
3608 }
3609 }
3610
3611 {
3612 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3613 // Make sure the watcher thread can be started by WatcherThread::start()
3614 // or by dynamic enrollment.
3615 WatcherThread::make_startable();
3616 // Start up the WatcherThread if there are any periodic tasks
3617 // NOTE: All PeriodicTasks should be registered by now. If they
3618 // aren't, late joiners might appear to start slowly (we might
3619 // take a while to process their first tick).
3620 if (PeriodicTask::num_tasks() > 0) {
3621 WatcherThread::start();
3622 }
3623 }
3624
3625 // Give os specific code one last chance to start
3626 os::init_3();
3627
3628 create_vm_timer.end();
3629 #ifdef ASSERT
3630 _vm_complete = true;
3631 #endif
3632 return JNI_OK;
3633 }
3634
3635 // type for the Agent_OnLoad and JVM_OnLoad entry points
3636 extern "C" {
3637 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3638 }
3639 // Find a command line agent library and return its entry point for
3640 // -agentlib: -agentpath: -Xrun
3641 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3642 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3643 OnLoadEntry_t on_load_entry = NULL;
3644 void *library = NULL;
3645
3646 if (!agent->valid()) {
3647 char buffer[JVM_MAXPATHLEN];
3648 char ebuf[1024];
3649 const char *name = agent->name();
3650 const char *msg = "Could not find agent library ";
3651
3652 // First check to see if agent is statically linked into executable
3653 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3654 library = agent->os_lib();
3655 } else if (agent->is_absolute_path()) {
3656 library = os::dll_load(name, ebuf, sizeof ebuf);
3657 if (library == NULL) {
3658 const char *sub_msg = " in absolute path, with error: ";
3659 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3660 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3661 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3662 // If we can't find the agent, exit.
3663 vm_exit_during_initialization(buf, NULL);
3664 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3665 }
3666 } else {
3667 // Try to load the agent from the standard dll directory
3668 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3669 name)) {
3670 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3671 }
3672 if (library == NULL) { // Try the local directory
3673 char ns[1] = {0};
3674 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3675 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3676 }
3677 if (library == NULL) {
3678 const char *sub_msg = " on the library path, with error: ";
3679 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3680 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3681 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3682 // If we can't find the agent, exit.
3683 vm_exit_during_initialization(buf, NULL);
3684 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3685 }
3686 }
3687 }
3688 agent->set_os_lib(library);
3689 agent->set_valid();
3690 }
3691
3692 // Find the OnLoad function.
3693 on_load_entry =
3694 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3695 false,
3696 on_load_symbols,
3697 num_symbol_entries));
3698 return on_load_entry;
3699 }
3700
3701 // Find the JVM_OnLoad entry point
3702 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3703 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3704 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3705 }
3706
3707 // Find the Agent_OnLoad entry point
3708 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3709 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3710 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3711 }
3712
3713 // For backwards compatibility with -Xrun
3714 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3715 // treated like -agentpath:
3716 // Must be called before agent libraries are created
3717 void Threads::convert_vm_init_libraries_to_agents() {
3718 AgentLibrary* agent;
3719 AgentLibrary* next;
3720
3721 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3722 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3723 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3724
3725 // If there is an JVM_OnLoad function it will get called later,
3726 // otherwise see if there is an Agent_OnLoad
3727 if (on_load_entry == NULL) {
3728 on_load_entry = lookup_agent_on_load(agent);
3729 if (on_load_entry != NULL) {
3730 // switch it to the agent list -- so that Agent_OnLoad will be called,
3731 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3732 Arguments::convert_library_to_agent(agent);
3733 } else {
3734 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3735 }
3736 }
3737 }
3738 }
3739
3740 // Create agents for -agentlib: -agentpath: and converted -Xrun
3741 // Invokes Agent_OnLoad
3742 // Called very early -- before JavaThreads exist
3743 void Threads::create_vm_init_agents() {
3744 extern struct JavaVM_ main_vm;
3745 AgentLibrary* agent;
3746
3747 JvmtiExport::enter_onload_phase();
3748
3749 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3750 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3751
3752 if (on_load_entry != NULL) {
3753 // Invoke the Agent_OnLoad function
3754 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3755 if (err != JNI_OK) {
3756 vm_exit_during_initialization("agent library failed to init", agent->name());
3757 }
3758 } else {
3759 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3760 }
3761 }
3762 JvmtiExport::enter_primordial_phase();
3763 }
3764
3765 extern "C" {
3766 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3767 }
3768
3769 void Threads::shutdown_vm_agents() {
3770 // Send any Agent_OnUnload notifications
3771 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3772 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3773 extern struct JavaVM_ main_vm;
3774 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3775
3776 // Find the Agent_OnUnload function.
3777 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3778 os::find_agent_function(agent,
3779 false,
3780 on_unload_symbols,
3781 num_symbol_entries));
3782
3783 // Invoke the Agent_OnUnload function
3784 if (unload_entry != NULL) {
3785 JavaThread* thread = JavaThread::current();
3786 ThreadToNativeFromVM ttn(thread);
3787 HandleMark hm(thread);
3788 (*unload_entry)(&main_vm);
3789 }
3790 }
3791 }
3792
3793 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3794 // Invokes JVM_OnLoad
3795 void Threads::create_vm_init_libraries() {
3796 extern struct JavaVM_ main_vm;
3797 AgentLibrary* agent;
3798
3799 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3800 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3801
3802 if (on_load_entry != NULL) {
3803 // Invoke the JVM_OnLoad function
3804 JavaThread* thread = JavaThread::current();
3805 ThreadToNativeFromVM ttn(thread);
3806 HandleMark hm(thread);
3807 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3808 if (err != JNI_OK) {
3809 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3810 }
3811 } else {
3812 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3813 }
3814 }
3815 }
3816
3817 // Last thread running calls java.lang.Shutdown.shutdown()
3818 void JavaThread::invoke_shutdown_hooks() {
3819 HandleMark hm(this);
3820
3821 // We could get here with a pending exception, if so clear it now.
3822 if (this->has_pending_exception()) {
3823 this->clear_pending_exception();
3824 }
3825
3826 EXCEPTION_MARK;
3827 Klass* k =
3828 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3829 THREAD);
3830 if (k != NULL) {
3831 // SystemDictionary::resolve_or_null will return null if there was
3832 // an exception. If we cannot load the Shutdown class, just don't
3833 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3834 // and finalizers (if runFinalizersOnExit is set) won't be run.
3835 // Note that if a shutdown hook was registered or runFinalizersOnExit
3836 // was called, the Shutdown class would have already been loaded
3837 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3838 instanceKlassHandle shutdown_klass (THREAD, k);
3839 JavaValue result(T_VOID);
3840 JavaCalls::call_static(&result,
3841 shutdown_klass,
3842 vmSymbols::shutdown_method_name(),
3843 vmSymbols::void_method_signature(),
3844 THREAD);
3845 }
3846 CLEAR_PENDING_EXCEPTION;
3847 }
3848
3849 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3850 // the program falls off the end of main(). Another VM exit path is through
3851 // vm_exit() when the program calls System.exit() to return a value or when
3852 // there is a serious error in VM. The two shutdown paths are not exactly
3853 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3854 // and VM_Exit op at VM level.
3855 //
3856 // Shutdown sequence:
3857 // + Shutdown native memory tracking if it is on
3858 // + Wait until we are the last non-daemon thread to execute
3859 // <-- every thing is still working at this moment -->
3860 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3861 // shutdown hooks, run finalizers if finalization-on-exit
3862 // + Call before_exit(), prepare for VM exit
3863 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3864 // currently the only user of this mechanism is File.deleteOnExit())
3865 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3866 // post thread end and vm death events to JVMTI,
3867 // stop signal thread
3868 // + Call JavaThread::exit(), it will:
3869 // > release JNI handle blocks, remove stack guard pages
3870 // > remove this thread from Threads list
3871 // <-- no more Java code from this thread after this point -->
3872 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3873 // the compiler threads at safepoint
3874 // <-- do not use anything that could get blocked by Safepoint -->
3875 // + Disable tracing at JNI/JVM barriers
3876 // + Set _vm_exited flag for threads that are still running native code
3877 // + Delete this thread
3878 // + Call exit_globals()
3879 // > deletes tty
3880 // > deletes PerfMemory resources
3881 // + Return to caller
3882
3883 bool Threads::destroy_vm() {
3884 JavaThread* thread = JavaThread::current();
3885
3886 #ifdef ASSERT
3887 _vm_complete = false;
3888 #endif
3889 // Wait until we are the last non-daemon thread to execute
3890 { MutexLocker nu(Threads_lock);
3891 while (Threads::number_of_non_daemon_threads() > 1)
3892 // This wait should make safepoint checks, wait without a timeout,
3893 // and wait as a suspend-equivalent condition.
3894 //
3895 // Note: If the FlatProfiler is running and this thread is waiting
3896 // for another non-daemon thread to finish, then the FlatProfiler
3897 // is waiting for the external suspend request on this thread to
3898 // complete. wait_for_ext_suspend_completion() will eventually
3899 // timeout, but that takes time. Making this wait a suspend-
3900 // equivalent condition solves that timeout problem.
3901 //
3902 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3903 Mutex::_as_suspend_equivalent_flag);
3904 }
3905
3906 // Hang forever on exit if we are reporting an error.
3907 if (ShowMessageBoxOnError && is_error_reported()) {
3908 os::infinite_sleep();
3909 }
3910 os::wait_for_keypress_at_exit();
3911
3912 // run Java level shutdown hooks
3913 thread->invoke_shutdown_hooks();
3914
3915 before_exit(thread);
3916
3917 thread->exit(true);
3918
3919 // Stop VM thread.
3920 {
3921 // 4945125 The vm thread comes to a safepoint during exit.
3922 // GC vm_operations can get caught at the safepoint, and the
3923 // heap is unparseable if they are caught. Grab the Heap_lock
3924 // to prevent this. The GC vm_operations will not be able to
3925 // queue until after the vm thread is dead. After this point,
3926 // we'll never emerge out of the safepoint before the VM exits.
3927
3928 MutexLocker ml(Heap_lock);
3929
3930 VMThread::wait_for_vm_thread_exit();
3931 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3932 VMThread::destroy();
3933 }
3934
3935 // clean up ideal graph printers
3936 #if defined(COMPILER2) && !defined(PRODUCT)
3937 IdealGraphPrinter::clean_up();
3938 #endif
3939
3940 // Now, all Java threads are gone except daemon threads. Daemon threads
3941 // running Java code or in VM are stopped by the Safepoint. However,
3942 // daemon threads executing native code are still running. But they
3943 // will be stopped at native=>Java/VM barriers. Note that we can't
3944 // simply kill or suspend them, as it is inherently deadlock-prone.
3945
3946 #ifndef PRODUCT
3947 // disable function tracing at JNI/JVM barriers
3948 TraceJNICalls = false;
3949 TraceJVMCalls = false;
3950 TraceRuntimeCalls = false;
3951 #endif
3952
3953 VM_Exit::set_vm_exited();
3954
3955 notify_vm_shutdown();
3956
3957 delete thread;
3958
3959 // exit_globals() will delete tty
3960 exit_globals();
3961
3962 return true;
3963 }
3964
3965
3966 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3967 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3968 return is_supported_jni_version(version);
3969 }
3970
3971
3972 jboolean Threads::is_supported_jni_version(jint version) {
3973 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3974 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3975 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3976 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3977 return JNI_FALSE;
3978 }
3979
3980
3981 void Threads::add(JavaThread* p, bool force_daemon) {
3982 // The threads lock must be owned at this point
3983 assert_locked_or_safepoint(Threads_lock);
3984
3985 // See the comment for this method in thread.hpp for its purpose and
3986 // why it is called here.
3987 p->initialize_queues();
3988 p->set_next(_thread_list);
3989 _thread_list = p;
3990 _number_of_threads++;
3991 oop threadObj = p->threadObj();
3992 bool daemon = true;
3993 // Bootstrapping problem: threadObj can be null for initial
3994 // JavaThread (or for threads attached via JNI)
3995 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3996 _number_of_non_daemon_threads++;
3997 daemon = false;
3998 }
3999
4000 p->set_safepoint_visible(true);
4001
4002 ThreadService::add_thread(p, daemon);
4003
4004 // Possible GC point.
4005 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4006 }
4007
4008 void Threads::remove(JavaThread* p) {
4009 // Extra scope needed for Thread_lock, so we can check
4010 // that we do not remove thread without safepoint code notice
4011 { MutexLocker ml(Threads_lock);
4012
4013 assert(includes(p), "p must be present");
4014
4015 JavaThread* current = _thread_list;
4016 JavaThread* prev = NULL;
4017
4018 while (current != p) {
4019 prev = current;
4020 current = current->next();
4021 }
4022
4023 if (prev) {
4024 prev->set_next(current->next());
4025 } else {
4026 _thread_list = p->next();
4027 }
4028 _number_of_threads--;
4029 oop threadObj = p->threadObj();
4030 bool daemon = true;
4031 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4032 _number_of_non_daemon_threads--;
4033 daemon = false;
4034
4035 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4036 // on destroy_vm will wake up.
4037 if (number_of_non_daemon_threads() == 1)
4038 Threads_lock->notify_all();
4039 }
4040 ThreadService::remove_thread(p, daemon);
4041
4042 // Make sure that safepoint code disregard this thread. This is needed since
4043 // the thread might mess around with locks after this point. This can cause it
4044 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4045 // of this thread since it is removed from the queue.
4046 p->set_terminated_value();
4047
4048 // Now, this thread is not visible to safepoint
4049 p->set_safepoint_visible(false);
4050 // once the thread becomes safepoint invisible, we can not use its per-thread
4051 // recorder. And Threads::do_threads() no longer walks this thread, so we have
4052 // to release its per-thread recorder here.
4053 MemTracker::thread_exiting(p);
4054 } // unlock Threads_lock
4055
4056 // Since Events::log uses a lock, we grab it outside the Threads_lock
4057 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4058 }
4059
4060 // Threads_lock must be held when this is called (or must be called during a safepoint)
4061 bool Threads::includes(JavaThread* p) {
4062 assert(Threads_lock->is_locked(), "sanity check");
4063 ALL_JAVA_THREADS(q) {
4064 if (q == p) {
4065 return true;
4066 }
4067 }
4068 return false;
4069 }
4070
4071 // Operations on the Threads list for GC. These are not explicitly locked,
4072 // but the garbage collector must provide a safe context for them to run.
4073 // In particular, these things should never be called when the Threads_lock
4074 // is held by some other thread. (Note: the Safepoint abstraction also
4075 // uses the Threads_lock to guarantee this property. It also makes sure that
4076 // all threads gets blocked when exiting or starting).
4077
4078 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4079 ALL_JAVA_THREADS(p) {
4080 p->oops_do(f, cld_f, cf);
4081 }
4082 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4083 }
4084
4085 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4086 // Introduce a mechanism allowing parallel threads to claim threads as
4087 // root groups. Overhead should be small enough to use all the time,
4088 // even in sequential code.
4089 SharedHeap* sh = SharedHeap::heap();
4090 // Cannot yet substitute active_workers for n_par_threads
4091 // because of G1CollectedHeap::verify() use of
4092 // SharedHeap::process_strong_roots(). n_par_threads == 0 will
4093 // turn off parallelism in process_strong_roots while active_workers
4094 // is being used for parallelism elsewhere.
4095 bool is_par = sh->n_par_threads() > 0;
4096 assert(!is_par ||
4097 (SharedHeap::heap()->n_par_threads() ==
4098 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4099 int cp = SharedHeap::heap()->strong_roots_parity();
4100 ALL_JAVA_THREADS(p) {
4101 if (p->claim_oops_do(is_par, cp)) {
4102 p->oops_do(f, cld_f, cf);
4103 }
4104 }
4105 VMThread* vmt = VMThread::vm_thread();
4106 if (vmt->claim_oops_do(is_par, cp)) {
4107 vmt->oops_do(f, cld_f, cf);
4108 }
4109 }
4110
4111 #if INCLUDE_ALL_GCS
4112 // Used by ParallelScavenge
4113 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4114 ALL_JAVA_THREADS(p) {
4115 q->enqueue(new ThreadRootsTask(p));
4116 }
4117 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4118 }
4119
4120 // Used by Parallel Old
4121 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4122 ALL_JAVA_THREADS(p) {
4123 q->enqueue(new ThreadRootsMarkingTask(p));
4124 }
4125 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4126 }
4127 #endif // INCLUDE_ALL_GCS
4128
4129 void Threads::nmethods_do(CodeBlobClosure* cf) {
4130 ALL_JAVA_THREADS(p) {
4131 p->nmethods_do(cf);
4132 }
4133 VMThread::vm_thread()->nmethods_do(cf);
4134 }
4135
4136 void Threads::metadata_do(void f(Metadata*)) {
4137 ALL_JAVA_THREADS(p) {
4138 p->metadata_do(f);
4139 }
4140 }
4141
4142 void Threads::gc_epilogue() {
4143 ALL_JAVA_THREADS(p) {
4144 p->gc_epilogue();
4145 }
4146 }
4147
4148 void Threads::gc_prologue() {
4149 ALL_JAVA_THREADS(p) {
4150 p->gc_prologue();
4151 }
4152 }
4153
4154 void Threads::deoptimized_wrt_marked_nmethods() {
4155 ALL_JAVA_THREADS(p) {
4156 p->deoptimized_wrt_marked_nmethods();
4157 }
4158 }
4159
4160
4161 // Get count Java threads that are waiting to enter the specified monitor.
4162 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4163 address monitor, bool doLock) {
4164 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4165 "must grab Threads_lock or be at safepoint");
4166 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4167
4168 int i = 0;
4169 {
4170 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4171 ALL_JAVA_THREADS(p) {
4172 if (p->is_Compiler_thread()) continue;
4173
4174 address pending = (address)p->current_pending_monitor();
4175 if (pending == monitor) { // found a match
4176 if (i < count) result->append(p); // save the first count matches
4177 i++;
4178 }
4179 }
4180 }
4181 return result;
4182 }
4183
4184
4185 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4186 assert(doLock ||
4187 Threads_lock->owned_by_self() ||
4188 SafepointSynchronize::is_at_safepoint(),
4189 "must grab Threads_lock or be at safepoint");
4190
4191 // NULL owner means not locked so we can skip the search
4192 if (owner == NULL) return NULL;
4193
4194 {
4195 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4196 ALL_JAVA_THREADS(p) {
4197 // first, see if owner is the address of a Java thread
4198 if (owner == (address)p) return p;
4199 }
4200 }
4201 // Cannot assert on lack of success here since this function may be
4202 // used by code that is trying to report useful problem information
4203 // like deadlock detection.
4204 if (UseHeavyMonitors) return NULL;
4205
4206 //
4207 // If we didn't find a matching Java thread and we didn't force use of
4208 // heavyweight monitors, then the owner is the stack address of the
4209 // Lock Word in the owning Java thread's stack.
4210 //
4211 JavaThread* the_owner = NULL;
4212 {
4213 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4214 ALL_JAVA_THREADS(q) {
4215 if (q->is_lock_owned(owner)) {
4216 the_owner = q;
4217 break;
4218 }
4219 }
4220 }
4221 // cannot assert on lack of success here; see above comment
4222 return the_owner;
4223 }
4224
4225 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4226 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4227 char buf[32];
4228 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4229
4230 st->print_cr("Full thread dump %s (%s %s):",
4231 Abstract_VM_Version::vm_name(),
4232 Abstract_VM_Version::vm_release(),
4233 Abstract_VM_Version::vm_info_string()
4234 );
4235 st->cr();
4236
4237 #if INCLUDE_ALL_GCS
4238 // Dump concurrent locks
4239 ConcurrentLocksDump concurrent_locks;
4240 if (print_concurrent_locks) {
4241 concurrent_locks.dump_at_safepoint();
4242 }
4243 #endif // INCLUDE_ALL_GCS
4244
4245 ALL_JAVA_THREADS(p) {
4246 ResourceMark rm;
4247 p->print_on(st);
4248 if (print_stacks) {
4249 if (internal_format) {
4250 p->trace_stack();
4251 } else {
4252 p->print_stack_on(st);
4253 }
4254 }
4255 st->cr();
4256 #if INCLUDE_ALL_GCS
4257 if (print_concurrent_locks) {
4258 concurrent_locks.print_locks_on(p, st);
4259 }
4260 #endif // INCLUDE_ALL_GCS
4261 }
4262
4263 VMThread::vm_thread()->print_on(st);
4264 st->cr();
4265 Universe::heap()->print_gc_threads_on(st);
4266 WatcherThread* wt = WatcherThread::watcher_thread();
4267 if (wt != NULL) {
4268 wt->print_on(st);
4269 st->cr();
4270 }
4271 CompileBroker::print_compiler_threads_on(st);
4272 st->flush();
4273 }
4274
4275 // Threads::print_on_error() is called by fatal error handler. It's possible
4276 // that VM is not at safepoint and/or current thread is inside signal handler.
4277 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4278 // memory (even in resource area), it might deadlock the error handler.
4279 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4280 bool found_current = false;
4281 st->print_cr("Java Threads: ( => current thread )");
4282 ALL_JAVA_THREADS(thread) {
4283 bool is_current = (current == thread);
4284 found_current = found_current || is_current;
4285
4286 st->print("%s", is_current ? "=>" : " ");
4287
4288 st->print(PTR_FORMAT, thread);
4289 st->print(" ");
4290 thread->print_on_error(st, buf, buflen);
4291 st->cr();
4292 }
4293 st->cr();
4294
4295 st->print_cr("Other Threads:");
4296 if (VMThread::vm_thread()) {
4297 bool is_current = (current == VMThread::vm_thread());
4298 found_current = found_current || is_current;
4299 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4300
4301 st->print(PTR_FORMAT, VMThread::vm_thread());
4302 st->print(" ");
4303 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4304 st->cr();
4305 }
4306 WatcherThread* wt = WatcherThread::watcher_thread();
4307 if (wt != NULL) {
4308 bool is_current = (current == wt);
4309 found_current = found_current || is_current;
4310 st->print("%s", is_current ? "=>" : " ");
4311
4312 st->print(PTR_FORMAT, wt);
4313 st->print(" ");
4314 wt->print_on_error(st, buf, buflen);
4315 st->cr();
4316 }
4317 if (!found_current) {
4318 st->cr();
4319 st->print("=>" PTR_FORMAT " (exited) ", current);
4320 current->print_on_error(st, buf, buflen);
4321 st->cr();
4322 }
4323 }
4324
4325 // Internal SpinLock and Mutex
4326 // Based on ParkEvent
4327
4328 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4329 //
4330 // We employ SpinLocks _only for low-contention, fixed-length
4331 // short-duration critical sections where we're concerned
4332 // about native mutex_t or HotSpot Mutex:: latency.
4333 // The mux construct provides a spin-then-block mutual exclusion
4334 // mechanism.
4335 //
4336 // Testing has shown that contention on the ListLock guarding gFreeList
4337 // is common. If we implement ListLock as a simple SpinLock it's common
4338 // for the JVM to devolve to yielding with little progress. This is true
4339 // despite the fact that the critical sections protected by ListLock are
4340 // extremely short.
4341 //
4342 // TODO-FIXME: ListLock should be of type SpinLock.
4343 // We should make this a 1st-class type, integrated into the lock
4344 // hierarchy as leaf-locks. Critically, the SpinLock structure
4345 // should have sufficient padding to avoid false-sharing and excessive
4346 // cache-coherency traffic.
4347
4348
4349 typedef volatile int SpinLockT;
4350
4351 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4352 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4353 return; // normal fast-path return
4354 }
4355
4356 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4357 TEVENT(SpinAcquire - ctx);
4358 int ctr = 0;
4359 int Yields = 0;
4360 for (;;) {
4361 while (*adr != 0) {
4362 ++ctr;
4363 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4364 if (Yields > 5) {
4365 os::naked_short_sleep(1);
4366 } else {
4367 os::NakedYield();
4368 ++Yields;
4369 }
4370 } else {
4371 SpinPause();
4372 }
4373 }
4374 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4375 }
4376 }
4377
4378 void Thread::SpinRelease (volatile int * adr) {
4379 assert(*adr != 0, "invariant");
4380 OrderAccess::fence(); // guarantee at least release consistency.
4381 // Roach-motel semantics.
4382 // It's safe if subsequent LDs and STs float "up" into the critical section,
4383 // but prior LDs and STs within the critical section can't be allowed
4384 // to reorder or float past the ST that releases the lock.
4385 *adr = 0;
4386 }
4387
4388 // muxAcquire and muxRelease:
4389 //
4390 // * muxAcquire and muxRelease support a single-word lock-word construct.
4391 // The LSB of the word is set IFF the lock is held.
4392 // The remainder of the word points to the head of a singly-linked list
4393 // of threads blocked on the lock.
4394 //
4395 // * The current implementation of muxAcquire-muxRelease uses its own
4396 // dedicated Thread._MuxEvent instance. If we're interested in
4397 // minimizing the peak number of extant ParkEvent instances then
4398 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4399 // as certain invariants were satisfied. Specifically, care would need
4400 // to be taken with regards to consuming unpark() "permits".
4401 // A safe rule of thumb is that a thread would never call muxAcquire()
4402 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4403 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4404 // consume an unpark() permit intended for monitorenter, for instance.
4405 // One way around this would be to widen the restricted-range semaphore
4406 // implemented in park(). Another alternative would be to provide
4407 // multiple instances of the PlatformEvent() for each thread. One
4408 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4409 //
4410 // * Usage:
4411 // -- Only as leaf locks
4412 // -- for short-term locking only as muxAcquire does not perform
4413 // thread state transitions.
4414 //
4415 // Alternatives:
4416 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4417 // but with parking or spin-then-park instead of pure spinning.
4418 // * Use Taura-Oyama-Yonenzawa locks.
4419 // * It's possible to construct a 1-0 lock if we encode the lockword as
4420 // (List,LockByte). Acquire will CAS the full lockword while Release
4421 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4422 // acquiring threads use timers (ParkTimed) to detect and recover from
4423 // the stranding window. Thread/Node structures must be aligned on 256-byte
4424 // boundaries by using placement-new.
4425 // * Augment MCS with advisory back-link fields maintained with CAS().
4426 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4427 // The validity of the backlinks must be ratified before we trust the value.
4428 // If the backlinks are invalid the exiting thread must back-track through the
4429 // the forward links, which are always trustworthy.
4430 // * Add a successor indication. The LockWord is currently encoded as
4431 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4432 // to provide the usual futile-wakeup optimization.
4433 // See RTStt for details.
4434 // * Consider schedctl.sc_nopreempt to cover the critical section.
4435 //
4436
4437
4438 typedef volatile intptr_t MutexT; // Mux Lock-word
4439 enum MuxBits { LOCKBIT = 1 };
4440
4441 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4442 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4443 if (w == 0) return;
4444 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4445 return;
4446 }
4447
4448 TEVENT(muxAcquire - Contention);
4449 ParkEvent * const Self = Thread::current()->_MuxEvent;
4450 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4451 for (;;) {
4452 int its = (os::is_MP() ? 100 : 0) + 1;
4453
4454 // Optional spin phase: spin-then-park strategy
4455 while (--its >= 0) {
4456 w = *Lock;
4457 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4458 return;
4459 }
4460 }
4461
4462 Self->reset();
4463 Self->OnList = intptr_t(Lock);
4464 // The following fence() isn't _strictly necessary as the subsequent
4465 // CAS() both serializes execution and ratifies the fetched *Lock value.
4466 OrderAccess::fence();
4467 for (;;) {
4468 w = *Lock;
4469 if ((w & LOCKBIT) == 0) {
4470 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4471 Self->OnList = 0; // hygiene - allows stronger asserts
4472 return;
4473 }
4474 continue; // Interference -- *Lock changed -- Just retry
4475 }
4476 assert(w & LOCKBIT, "invariant");
4477 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4478 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4479 }
4480
4481 while (Self->OnList != 0) {
4482 Self->park();
4483 }
4484 }
4485 }
4486
4487 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4488 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4489 if (w == 0) return;
4490 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4491 return;
4492 }
4493
4494 TEVENT(muxAcquire - Contention);
4495 ParkEvent * ReleaseAfter = NULL;
4496 if (ev == NULL) {
4497 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4498 }
4499 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4500 for (;;) {
4501 guarantee(ev->OnList == 0, "invariant");
4502 int its = (os::is_MP() ? 100 : 0) + 1;
4503
4504 // Optional spin phase: spin-then-park strategy
4505 while (--its >= 0) {
4506 w = *Lock;
4507 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4508 if (ReleaseAfter != NULL) {
4509 ParkEvent::Release(ReleaseAfter);
4510 }
4511 return;
4512 }
4513 }
4514
4515 ev->reset();
4516 ev->OnList = intptr_t(Lock);
4517 // The following fence() isn't _strictly necessary as the subsequent
4518 // CAS() both serializes execution and ratifies the fetched *Lock value.
4519 OrderAccess::fence();
4520 for (;;) {
4521 w = *Lock;
4522 if ((w & LOCKBIT) == 0) {
4523 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4524 ev->OnList = 0;
4525 // We call ::Release while holding the outer lock, thus
4526 // artificially lengthening the critical section.
4527 // Consider deferring the ::Release() until the subsequent unlock(),
4528 // after we've dropped the outer lock.
4529 if (ReleaseAfter != NULL) {
4530 ParkEvent::Release(ReleaseAfter);
4531 }
4532 return;
4533 }
4534 continue; // Interference -- *Lock changed -- Just retry
4535 }
4536 assert(w & LOCKBIT, "invariant");
4537 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4538 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4539 }
4540
4541 while (ev->OnList != 0) {
4542 ev->park();
4543 }
4544 }
4545 }
4546
4547 // Release() must extract a successor from the list and then wake that thread.
4548 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4549 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4550 // Release() would :
4551 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4552 // (B) Extract a successor from the private list "in-hand"
4553 // (C) attempt to CAS() the residual back into *Lock over null.
4554 // If there were any newly arrived threads and the CAS() would fail.
4555 // In that case Release() would detach the RATs, re-merge the list in-hand
4556 // with the RATs and repeat as needed. Alternately, Release() might
4557 // detach and extract a successor, but then pass the residual list to the wakee.
4558 // The wakee would be responsible for reattaching and remerging before it
4559 // competed for the lock.
4560 //
4561 // Both "pop" and DMR are immune from ABA corruption -- there can be
4562 // multiple concurrent pushers, but only one popper or detacher.
4563 // This implementation pops from the head of the list. This is unfair,
4564 // but tends to provide excellent throughput as hot threads remain hot.
4565 // (We wake recently run threads first).
4566
4567 void Thread::muxRelease (volatile intptr_t * Lock) {
4568 for (;;) {
4569 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4570 assert(w & LOCKBIT, "invariant");
4571 if (w == LOCKBIT) return;
4572 ParkEvent * List = (ParkEvent *)(w & ~LOCKBIT);
4573 assert(List != NULL, "invariant");
4574 assert(List->OnList == intptr_t(Lock), "invariant");
4575 ParkEvent * nxt = List->ListNext;
4576
4577 // The following CAS() releases the lock and pops the head element.
4578 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4579 continue;
4580 }
4581 List->OnList = 0;
4582 OrderAccess::fence();
4583 List->unpark();
4584 return;
4585 }
4586 }
4587
4588
4589 void Threads::verify() {
4590 ALL_JAVA_THREADS(p) {
4591 p->verify();
4592 }
4593 VMThread* thread = VMThread::vm_thread();
4594 if (thread != NULL) thread->verify();
4595 }