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