1 /*
2 * Copyright (c) 1997, 2015, 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/codeCache.hpp"
31 #include "code/scopeDesc.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "interpreter/linkResolver.hpp"
35 #include "interpreter/oopMapCache.hpp"
36 #include "jvmtifiles/jvmtiEnv.hpp"
37 #include "memory/gcLocker.inline.hpp"
38 #include "memory/metaspaceShared.hpp"
39 #include "memory/oopFactory.hpp"
40 #include "memory/universe.inline.hpp"
41 #include "oops/instanceKlass.hpp"
42 #include "oops/objArrayOop.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "oops/symbol.hpp"
45 #include "oops/verifyOopClosure.hpp"
46 #include "prims/jvm_misc.hpp"
47 #include "prims/jvmtiExport.hpp"
48 #include "prims/jvmtiThreadState.hpp"
49 #include "prims/privilegedStack.hpp"
50 #include "runtime/arguments.hpp"
51 #include "runtime/atomic.inline.hpp"
52 #include "runtime/biasedLocking.hpp"
53 #include "runtime/deoptimization.hpp"
54 #include "runtime/fprofiler.hpp"
55 #include "runtime/frame.inline.hpp"
56 #include "runtime/init.hpp"
57 #include "runtime/interfaceSupport.hpp"
58 #include "runtime/java.hpp"
59 #include "runtime/javaCalls.hpp"
60 #include "runtime/jniPeriodicChecker.hpp"
61 #include "runtime/memprofiler.hpp"
62 #include "runtime/mutexLocker.hpp"
63 #include "runtime/objectMonitor.hpp"
64 #include "runtime/orderAccess.inline.hpp"
65 #include "runtime/osThread.hpp"
66 #include "runtime/safepoint.hpp"
67 #include "runtime/sharedRuntime.hpp"
68 #include "runtime/statSampler.hpp"
69 #include "runtime/stubRoutines.hpp"
70 #include "runtime/sweeper.hpp"
71 #include "runtime/task.hpp"
72 #include "runtime/thread.inline.hpp"
73 #include "runtime/threadCritical.hpp"
74 #include "runtime/threadLocalStorage.hpp"
75 #include "runtime/vframe.hpp"
76 #include "runtime/vframeArray.hpp"
77 #include "runtime/vframe_hp.hpp"
78 #include "runtime/vmThread.hpp"
79 #include "runtime/vm_operations.hpp"
80 #include "runtime/vm_version.hpp"
81 #include "services/attachListener.hpp"
82 #include "services/management.hpp"
83 #include "services/memTracker.hpp"
84 #include "services/threadService.hpp"
85 #include "trace/tracing.hpp"
86 #include "trace/traceMacros.hpp"
87 #include "utilities/defaultStream.hpp"
88 #include "utilities/dtrace.hpp"
89 #include "utilities/events.hpp"
90 #include "utilities/macros.hpp"
91 #include "utilities/preserveException.hpp"
92 #include "utilities/workgroup.hpp"
93 #if INCLUDE_ALL_GCS
94 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
95 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
96 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
97 #endif // INCLUDE_ALL_GCS
98 #ifdef COMPILER1
99 #include "c1/c1_Compiler.hpp"
100 #endif
101 #ifdef COMPILER2
102 #include "opto/c2compiler.hpp"
103 #include "opto/idealGraphPrinter.hpp"
104 #endif
105 #if INCLUDE_RTM_OPT
106 #include "runtime/rtmLocking.hpp"
107 #endif
108
109 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
110
111 #ifdef DTRACE_ENABLED
112
113 // Only bother with this argument setup if dtrace is available
114
115 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
116 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
117
118 #define DTRACE_THREAD_PROBE(probe, javathread) \
119 { \
120 ResourceMark rm(this); \
121 int len = 0; \
122 const char* name = (javathread)->get_thread_name(); \
123 len = strlen(name); \
124 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
125 (char *) name, len, \
126 java_lang_Thread::thread_id((javathread)->threadObj()), \
127 (uintptr_t) (javathread)->osthread()->thread_id(), \
128 java_lang_Thread::is_daemon((javathread)->threadObj())); \
129 }
130
131 #else // ndef DTRACE_ENABLED
132
133 #define DTRACE_THREAD_PROBE(probe, javathread)
134
135 #endif // ndef DTRACE_ENABLED
136
137
138 // Class hierarchy
139 // - Thread
140 // - VMThread
141 // - WatcherThread
142 // - ConcurrentMarkSweepThread
143 // - JavaThread
144 // - CompilerThread
145
146 // ======= Thread ========
147 // Support for forcing alignment of thread objects for biased locking
148 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
149 if (UseBiasedLocking) {
150 const int alignment = markOopDesc::biased_lock_alignment;
151 size_t aligned_size = size + (alignment - sizeof(intptr_t));
152 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
153 : AllocateHeap(aligned_size, flags, CURRENT_PC,
154 AllocFailStrategy::RETURN_NULL);
155 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
156 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
157 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
158 "JavaThread alignment code overflowed allocated storage");
159 if (TraceBiasedLocking) {
160 if (aligned_addr != real_malloc_addr) {
161 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
162 real_malloc_addr, aligned_addr);
163 }
164 }
165 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
166 return aligned_addr;
167 } else {
168 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
169 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
170 }
171 }
172
173 void Thread::operator delete(void* p) {
174 if (UseBiasedLocking) {
175 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
176 FreeHeap(real_malloc_addr);
177 } else {
178 FreeHeap(p);
179 }
180 }
181
182
183 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
184 // JavaThread
185
186
187 Thread::Thread() {
188 // stack and get_thread
189 set_stack_base(NULL);
190 set_stack_size(0);
191 set_self_raw_id(0);
192 set_lgrp_id(-1);
193
194 // allocated data structures
195 set_osthread(NULL);
196 set_resource_area(new (mtThread)ResourceArea());
197 DEBUG_ONLY(_current_resource_mark = NULL;)
198 set_handle_area(new (mtThread) HandleArea(NULL));
199 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
200 set_active_handles(NULL);
201 set_free_handle_block(NULL);
202 set_last_handle_mark(NULL);
203
204 // This initial value ==> never claimed.
205 _oops_do_parity = 0;
206
207 // the handle mark links itself to last_handle_mark
208 new HandleMark(this);
209
210 // plain initialization
211 debug_only(_owned_locks = NULL;)
212 debug_only(_allow_allocation_count = 0;)
213 NOT_PRODUCT(_allow_safepoint_count = 0;)
214 NOT_PRODUCT(_skip_gcalot = false;)
215 _jvmti_env_iteration_count = 0;
216 set_allocated_bytes(0);
217 _vm_operation_started_count = 0;
218 _vm_operation_completed_count = 0;
219 _current_pending_monitor = NULL;
220 _current_pending_monitor_is_from_java = true;
221 _current_waiting_monitor = NULL;
222 _num_nested_signal = 0;
223 omFreeList = NULL;
224 omFreeCount = 0;
225 omFreeProvision = 32;
226 omInUseList = NULL;
227 omInUseCount = 0;
228
229 #ifdef ASSERT
230 _visited_for_critical_count = false;
231 #endif
232
233 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
234 Monitor::_safepoint_check_sometimes);
235 _suspend_flags = 0;
236
237 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
238 _hashStateX = os::random();
239 _hashStateY = 842502087;
240 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
241 _hashStateW = 273326509;
242
243 _OnTrap = 0;
244 _schedctl = NULL;
245 _Stalled = 0;
246 _TypeTag = 0x2BAD;
247
248 // Many of the following fields are effectively final - immutable
249 // Note that nascent threads can't use the Native Monitor-Mutex
250 // construct until the _MutexEvent is initialized ...
251 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
252 // we might instead use a stack of ParkEvents that we could provision on-demand.
253 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
254 // and ::Release()
255 _ParkEvent = ParkEvent::Allocate(this);
256 _SleepEvent = ParkEvent::Allocate(this);
257 _MutexEvent = ParkEvent::Allocate(this);
258 _MuxEvent = ParkEvent::Allocate(this);
259
260 #ifdef CHECK_UNHANDLED_OOPS
261 if (CheckUnhandledOops) {
262 _unhandled_oops = new UnhandledOops(this);
263 }
264 #endif // CHECK_UNHANDLED_OOPS
265 #ifdef ASSERT
266 if (UseBiasedLocking) {
267 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
268 assert(this == _real_malloc_address ||
269 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
270 "bug in forced alignment of thread objects");
271 }
272 #endif // ASSERT
273 }
274
275 void Thread::initialize_thread_local_storage() {
276 // Note: Make sure this method only calls
277 // non-blocking operations. Otherwise, it might not work
278 // with the thread-startup/safepoint interaction.
279
280 // During Java thread startup, safepoint code should allow this
281 // method to complete because it may need to allocate memory to
282 // store information for the new thread.
283
284 // initialize structure dependent on thread local storage
285 ThreadLocalStorage::set_thread(this);
286 }
287
288 void Thread::record_stack_base_and_size() {
289 set_stack_base(os::current_stack_base());
290 set_stack_size(os::current_stack_size());
291 if (is_Java_thread()) {
292 ((JavaThread*) this)->set_stack_overflow_limit();
293 }
294 // CR 7190089: on Solaris, primordial thread's stack is adjusted
295 // in initialize_thread(). Without the adjustment, stack size is
296 // incorrect if stack is set to unlimited (ulimit -s unlimited).
297 // So far, only Solaris has real implementation of initialize_thread().
298 //
299 // set up any platform-specific state.
300 os::initialize_thread(this);
301
302 #if INCLUDE_NMT
303 // record thread's native stack, stack grows downward
304 address stack_low_addr = stack_base() - stack_size();
305 MemTracker::record_thread_stack(stack_low_addr, stack_size());
306 #endif // INCLUDE_NMT
307 }
308
309
310 Thread::~Thread() {
311 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
312 ObjectSynchronizer::omFlush(this);
313
314 EVENT_THREAD_DESTRUCT(this);
315
316 // stack_base can be NULL if the thread is never started or exited before
317 // record_stack_base_and_size called. Although, we would like to ensure
318 // that all started threads do call record_stack_base_and_size(), there is
319 // not proper way to enforce that.
320 #if INCLUDE_NMT
321 if (_stack_base != NULL) {
322 address low_stack_addr = stack_base() - stack_size();
323 MemTracker::release_thread_stack(low_stack_addr, stack_size());
324 #ifdef ASSERT
325 set_stack_base(NULL);
326 #endif
327 }
328 #endif // INCLUDE_NMT
329
330 // deallocate data structures
331 delete resource_area();
332 // since the handle marks are using the handle area, we have to deallocated the root
333 // handle mark before deallocating the thread's handle area,
334 assert(last_handle_mark() != NULL, "check we have an element");
335 delete last_handle_mark();
336 assert(last_handle_mark() == NULL, "check we have reached the end");
337
338 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
339 // We NULL out the fields for good hygiene.
340 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
341 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
342 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
343 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
344
345 delete handle_area();
346 delete metadata_handles();
347
348 // osthread() can be NULL, if creation of thread failed.
349 if (osthread() != NULL) os::free_thread(osthread());
350
351 delete _SR_lock;
352
353 // clear thread local storage if the Thread is deleting itself
354 if (this == Thread::current()) {
355 ThreadLocalStorage::set_thread(NULL);
356 } else {
357 // In the case where we're not the current thread, invalidate all the
358 // caches in case some code tries to get the current thread or the
359 // thread that was destroyed, and gets stale information.
360 ThreadLocalStorage::invalidate_all();
361 }
362 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
363 }
364
365 // NOTE: dummy function for assertion purpose.
366 void Thread::run() {
367 ShouldNotReachHere();
368 }
369
370 #ifdef ASSERT
371 // Private method to check for dangling thread pointer
372 void check_for_dangling_thread_pointer(Thread *thread) {
373 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
374 "possibility of dangling Thread pointer");
375 }
376 #endif
377
378 ThreadPriority Thread::get_priority(const Thread* const thread) {
379 ThreadPriority priority;
380 // Can return an error!
381 (void)os::get_priority(thread, priority);
382 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
383 return priority;
384 }
385
386 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
387 debug_only(check_for_dangling_thread_pointer(thread);)
388 // Can return an error!
389 (void)os::set_priority(thread, priority);
390 }
391
392
393 void Thread::start(Thread* thread) {
394 // Start is different from resume in that its safety is guaranteed by context or
395 // being called from a Java method synchronized on the Thread object.
396 if (!DisableStartThread) {
397 if (thread->is_Java_thread()) {
398 // Initialize the thread state to RUNNABLE before starting this thread.
399 // Can not set it after the thread started because we do not know the
400 // exact thread state at that time. It could be in MONITOR_WAIT or
401 // in SLEEPING or some other state.
402 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
403 java_lang_Thread::RUNNABLE);
404 }
405 os::start_thread(thread);
406 }
407 }
408
409 // Enqueue a VM_Operation to do the job for us - sometime later
410 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
411 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
412 VMThread::execute(vm_stop);
413 }
414
415
416 // Check if an external suspend request has completed (or has been
417 // cancelled). Returns true if the thread is externally suspended and
418 // false otherwise.
419 //
420 // The bits parameter returns information about the code path through
421 // the routine. Useful for debugging:
422 //
423 // set in is_ext_suspend_completed():
424 // 0x00000001 - routine was entered
425 // 0x00000010 - routine return false at end
426 // 0x00000100 - thread exited (return false)
427 // 0x00000200 - suspend request cancelled (return false)
428 // 0x00000400 - thread suspended (return true)
429 // 0x00001000 - thread is in a suspend equivalent state (return true)
430 // 0x00002000 - thread is native and walkable (return true)
431 // 0x00004000 - thread is native_trans and walkable (needed retry)
432 //
433 // set in wait_for_ext_suspend_completion():
434 // 0x00010000 - routine was entered
435 // 0x00020000 - suspend request cancelled before loop (return false)
436 // 0x00040000 - thread suspended before loop (return true)
437 // 0x00080000 - suspend request cancelled in loop (return false)
438 // 0x00100000 - thread suspended in loop (return true)
439 // 0x00200000 - suspend not completed during retry loop (return false)
440
441 // Helper class for tracing suspend wait debug bits.
442 //
443 // 0x00000100 indicates that the target thread exited before it could
444 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
445 // 0x00080000 each indicate a cancelled suspend request so they don't
446 // count as wait failures either.
447 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
448
449 class TraceSuspendDebugBits : public StackObj {
450 private:
451 JavaThread * jt;
452 bool is_wait;
453 bool called_by_wait; // meaningful when !is_wait
454 uint32_t * bits;
455
456 public:
457 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
458 uint32_t *_bits) {
459 jt = _jt;
460 is_wait = _is_wait;
461 called_by_wait = _called_by_wait;
462 bits = _bits;
463 }
464
465 ~TraceSuspendDebugBits() {
466 if (!is_wait) {
467 #if 1
468 // By default, don't trace bits for is_ext_suspend_completed() calls.
469 // That trace is very chatty.
470 return;
471 #else
472 if (!called_by_wait) {
473 // If tracing for is_ext_suspend_completed() is enabled, then only
474 // trace calls to it from wait_for_ext_suspend_completion()
475 return;
476 }
477 #endif
478 }
479
480 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
481 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
482 MutexLocker ml(Threads_lock); // needed for get_thread_name()
483 ResourceMark rm;
484
485 tty->print_cr(
486 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
487 jt->get_thread_name(), *bits);
488
489 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
490 }
491 }
492 }
493 };
494 #undef DEBUG_FALSE_BITS
495
496
497 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
498 uint32_t *bits) {
499 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
500
501 bool did_trans_retry = false; // only do thread_in_native_trans retry once
502 bool do_trans_retry; // flag to force the retry
503
504 *bits |= 0x00000001;
505
506 do {
507 do_trans_retry = false;
508
509 if (is_exiting()) {
510 // Thread is in the process of exiting. This is always checked
511 // first to reduce the risk of dereferencing a freed JavaThread.
512 *bits |= 0x00000100;
513 return false;
514 }
515
516 if (!is_external_suspend()) {
517 // Suspend request is cancelled. This is always checked before
518 // is_ext_suspended() to reduce the risk of a rogue resume
519 // confusing the thread that made the suspend request.
520 *bits |= 0x00000200;
521 return false;
522 }
523
524 if (is_ext_suspended()) {
525 // thread is suspended
526 *bits |= 0x00000400;
527 return true;
528 }
529
530 // Now that we no longer do hard suspends of threads running
531 // native code, the target thread can be changing thread state
532 // while we are in this routine:
533 //
534 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
535 //
536 // We save a copy of the thread state as observed at this moment
537 // and make our decision about suspend completeness based on the
538 // copy. This closes the race where the thread state is seen as
539 // _thread_in_native_trans in the if-thread_blocked check, but is
540 // seen as _thread_blocked in if-thread_in_native_trans check.
541 JavaThreadState save_state = thread_state();
542
543 if (save_state == _thread_blocked && is_suspend_equivalent()) {
544 // If the thread's state is _thread_blocked and this blocking
545 // condition is known to be equivalent to a suspend, then we can
546 // consider the thread to be externally suspended. This means that
547 // the code that sets _thread_blocked has been modified to do
548 // self-suspension if the blocking condition releases. We also
549 // used to check for CONDVAR_WAIT here, but that is now covered by
550 // the _thread_blocked with self-suspension check.
551 //
552 // Return true since we wouldn't be here unless there was still an
553 // external suspend request.
554 *bits |= 0x00001000;
555 return true;
556 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
557 // Threads running native code will self-suspend on native==>VM/Java
558 // transitions. If its stack is walkable (should always be the case
559 // unless this function is called before the actual java_suspend()
560 // call), then the wait is done.
561 *bits |= 0x00002000;
562 return true;
563 } else if (!called_by_wait && !did_trans_retry &&
564 save_state == _thread_in_native_trans &&
565 frame_anchor()->walkable()) {
566 // The thread is transitioning from thread_in_native to another
567 // thread state. check_safepoint_and_suspend_for_native_trans()
568 // will force the thread to self-suspend. If it hasn't gotten
569 // there yet we may have caught the thread in-between the native
570 // code check above and the self-suspend. Lucky us. If we were
571 // called by wait_for_ext_suspend_completion(), then it
572 // will be doing the retries so we don't have to.
573 //
574 // Since we use the saved thread state in the if-statement above,
575 // there is a chance that the thread has already transitioned to
576 // _thread_blocked by the time we get here. In that case, we will
577 // make a single unnecessary pass through the logic below. This
578 // doesn't hurt anything since we still do the trans retry.
579
580 *bits |= 0x00004000;
581
582 // Once the thread leaves thread_in_native_trans for another
583 // thread state, we break out of this retry loop. We shouldn't
584 // need this flag to prevent us from getting back here, but
585 // sometimes paranoia is good.
586 did_trans_retry = true;
587
588 // We wait for the thread to transition to a more usable state.
589 for (int i = 1; i <= SuspendRetryCount; i++) {
590 // We used to do an "os::yield_all(i)" call here with the intention
591 // that yielding would increase on each retry. However, the parameter
592 // is ignored on Linux which means the yield didn't scale up. Waiting
593 // on the SR_lock below provides a much more predictable scale up for
594 // the delay. It also provides a simple/direct point to check for any
595 // safepoint requests from the VMThread
596
597 // temporarily drops SR_lock while doing wait with safepoint check
598 // (if we're a JavaThread - the WatcherThread can also call this)
599 // and increase delay with each retry
600 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
601
602 // check the actual thread state instead of what we saved above
603 if (thread_state() != _thread_in_native_trans) {
604 // the thread has transitioned to another thread state so
605 // try all the checks (except this one) one more time.
606 do_trans_retry = true;
607 break;
608 }
609 } // end retry loop
610
611
612 }
613 } while (do_trans_retry);
614
615 *bits |= 0x00000010;
616 return false;
617 }
618
619 // Wait for an external suspend request to complete (or be cancelled).
620 // Returns true if the thread is externally suspended and false otherwise.
621 //
622 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
623 uint32_t *bits) {
624 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
625 false /* !called_by_wait */, bits);
626
627 // local flag copies to minimize SR_lock hold time
628 bool is_suspended;
629 bool pending;
630 uint32_t reset_bits;
631
632 // set a marker so is_ext_suspend_completed() knows we are the caller
633 *bits |= 0x00010000;
634
635 // We use reset_bits to reinitialize the bits value at the top of
636 // each retry loop. This allows the caller to make use of any
637 // unused bits for their own marking purposes.
638 reset_bits = *bits;
639
640 {
641 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
642 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
643 delay, bits);
644 pending = is_external_suspend();
645 }
646 // must release SR_lock to allow suspension to complete
647
648 if (!pending) {
649 // A cancelled suspend request is the only false return from
650 // is_ext_suspend_completed() that keeps us from entering the
651 // retry loop.
652 *bits |= 0x00020000;
653 return false;
654 }
655
656 if (is_suspended) {
657 *bits |= 0x00040000;
658 return true;
659 }
660
661 for (int i = 1; i <= retries; i++) {
662 *bits = reset_bits; // reinit to only track last retry
663
664 // We used to do an "os::yield_all(i)" call here with the intention
665 // that yielding would increase on each retry. However, the parameter
666 // is ignored on Linux which means the yield didn't scale up. Waiting
667 // on the SR_lock below provides a much more predictable scale up for
668 // the delay. It also provides a simple/direct point to check for any
669 // safepoint requests from the VMThread
670
671 {
672 MutexLocker ml(SR_lock());
673 // wait with safepoint check (if we're a JavaThread - the WatcherThread
674 // can also call this) and increase delay with each retry
675 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
676
677 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
678 delay, bits);
679
680 // It is possible for the external suspend request to be cancelled
681 // (by a resume) before the actual suspend operation is completed.
682 // Refresh our local copy to see if we still need to wait.
683 pending = is_external_suspend();
684 }
685
686 if (!pending) {
687 // A cancelled suspend request is the only false return from
688 // is_ext_suspend_completed() that keeps us from staying in the
689 // retry loop.
690 *bits |= 0x00080000;
691 return false;
692 }
693
694 if (is_suspended) {
695 *bits |= 0x00100000;
696 return true;
697 }
698 } // end retry loop
699
700 // thread did not suspend after all our retries
701 *bits |= 0x00200000;
702 return false;
703 }
704
705 #ifndef PRODUCT
706 void JavaThread::record_jump(address target, address instr, const char* file,
707 int line) {
708
709 // This should not need to be atomic as the only way for simultaneous
710 // updates is via interrupts. Even then this should be rare or non-existent
711 // and we don't care that much anyway.
712
713 int index = _jmp_ring_index;
714 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
715 _jmp_ring[index]._target = (intptr_t) target;
716 _jmp_ring[index]._instruction = (intptr_t) instr;
717 _jmp_ring[index]._file = file;
718 _jmp_ring[index]._line = line;
719 }
720 #endif // PRODUCT
721
722 // Called by flat profiler
723 // Callers have already called wait_for_ext_suspend_completion
724 // The assertion for that is currently too complex to put here:
725 bool JavaThread::profile_last_Java_frame(frame* _fr) {
726 bool gotframe = false;
727 // self suspension saves needed state.
728 if (has_last_Java_frame() && _anchor.walkable()) {
729 *_fr = pd_last_frame();
730 gotframe = true;
731 }
732 return gotframe;
733 }
734
735 void Thread::interrupt(Thread* thread) {
736 debug_only(check_for_dangling_thread_pointer(thread);)
737 os::interrupt(thread);
738 }
739
740 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
741 debug_only(check_for_dangling_thread_pointer(thread);)
742 // Note: If clear_interrupted==false, this simply fetches and
743 // returns the value of the field osthread()->interrupted().
744 return os::is_interrupted(thread, clear_interrupted);
745 }
746
747
748 // GC Support
749 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
750 jint thread_parity = _oops_do_parity;
751 if (thread_parity != strong_roots_parity) {
752 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
753 if (res == thread_parity) {
754 return true;
755 } else {
756 guarantee(res == strong_roots_parity, "Or else what?");
757 assert(SharedHeap::heap()->workers()->active_workers() > 0,
758 "Should only fail when parallel.");
759 return false;
760 }
761 }
762 assert(SharedHeap::heap()->workers()->active_workers() > 0,
763 "Should only fail when parallel.");
764 return false;
765 }
766
767 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
768 active_handles()->oops_do(f);
769 // Do oop for ThreadShadow
770 f->do_oop((oop*)&_pending_exception);
771 handle_area()->oops_do(f);
772 }
773
774 void Thread::nmethods_do(CodeBlobClosure* cf) {
775 // no nmethods in a generic thread...
776 }
777
778 void Thread::metadata_handles_do(void f(Metadata*)) {
779 // Only walk the Handles in Thread.
780 if (metadata_handles() != NULL) {
781 for (int i = 0; i< metadata_handles()->length(); i++) {
782 f(metadata_handles()->at(i));
783 }
784 }
785 }
786
787 void Thread::print_on(outputStream* st) const {
788 // get_priority assumes osthread initialized
789 if (osthread() != NULL) {
790 int os_prio;
791 if (os::get_native_priority(this, &os_prio) == OS_OK) {
792 st->print("os_prio=%d ", os_prio);
793 }
794 st->print("tid=" INTPTR_FORMAT " ", this);
795 ext().print_on(st);
796 osthread()->print_on(st);
797 }
798 debug_only(if (WizardMode) print_owned_locks_on(st);)
799 }
800
801 // Thread::print_on_error() is called by fatal error handler. Don't use
802 // any lock or allocate memory.
803 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
804 if (is_VM_thread()) st->print("VMThread");
805 else if (is_Compiler_thread()) st->print("CompilerThread");
806 else if (is_Java_thread()) st->print("JavaThread");
807 else if (is_GC_task_thread()) st->print("GCTaskThread");
808 else if (is_Watcher_thread()) st->print("WatcherThread");
809 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
810 else st->print("Thread");
811
812 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
813 _stack_base - _stack_size, _stack_base);
814
815 if (osthread()) {
816 st->print(" [id=%d]", osthread()->thread_id());
817 }
818 }
819
820 #ifdef ASSERT
821 void Thread::print_owned_locks_on(outputStream* st) const {
822 Monitor *cur = _owned_locks;
823 if (cur == NULL) {
824 st->print(" (no locks) ");
825 } else {
826 st->print_cr(" Locks owned:");
827 while (cur) {
828 cur->print_on(st);
829 cur = cur->next();
830 }
831 }
832 }
833
834 static int ref_use_count = 0;
835
836 bool Thread::owns_locks_but_compiled_lock() const {
837 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
838 if (cur != Compile_lock) return true;
839 }
840 return false;
841 }
842
843
844 #endif
845
846 #ifndef PRODUCT
847
848 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
849 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
850 // no threads which allow_vm_block's are held
851 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
852 // Check if current thread is allowed to block at a safepoint
853 if (!(_allow_safepoint_count == 0)) {
854 fatal("Possible safepoint reached by thread that does not allow it");
855 }
856 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
857 fatal("LEAF method calling lock?");
858 }
859
860 #ifdef ASSERT
861 if (potential_vm_operation && is_Java_thread()
862 && !Universe::is_bootstrapping()) {
863 // Make sure we do not hold any locks that the VM thread also uses.
864 // This could potentially lead to deadlocks
865 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
866 // Threads_lock is special, since the safepoint synchronization will not start before this is
867 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
868 // since it is used to transfer control between JavaThreads and the VMThread
869 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
870 if ((cur->allow_vm_block() &&
871 cur != Threads_lock &&
872 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
873 cur != VMOperationRequest_lock &&
874 cur != VMOperationQueue_lock) ||
875 cur->rank() == Mutex::special) {
876 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
877 }
878 }
879 }
880
881 if (GCALotAtAllSafepoints) {
882 // We could enter a safepoint here and thus have a gc
883 InterfaceSupport::check_gc_alot();
884 }
885 #endif
886 }
887 #endif
888
889 bool Thread::is_in_stack(address adr) const {
890 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
891 address end = os::current_stack_pointer();
892 // Allow non Java threads to call this without stack_base
893 if (_stack_base == NULL) return true;
894 if (stack_base() >= adr && adr >= end) return true;
895
896 return false;
897 }
898
899
900 bool Thread::is_in_usable_stack(address adr) const {
901 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
902 size_t usable_stack_size = _stack_size - stack_guard_size;
903
904 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
905 }
906
907
908 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
909 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
910 // used for compilation in the future. If that change is made, the need for these methods
911 // should be revisited, and they should be removed if possible.
912
913 bool Thread::is_lock_owned(address adr) const {
914 return on_local_stack(adr);
915 }
916
917 bool Thread::set_as_starting_thread() {
918 // NOTE: this must be called inside the main thread.
919 return os::create_main_thread((JavaThread*)this);
920 }
921
922 static void initialize_class(Symbol* class_name, TRAPS) {
923 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
924 InstanceKlass::cast(klass)->initialize(CHECK);
925 }
926
927
928 // Creates the initial ThreadGroup
929 static Handle create_initial_thread_group(TRAPS) {
930 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
931 instanceKlassHandle klass (THREAD, k);
932
933 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
934 {
935 JavaValue result(T_VOID);
936 JavaCalls::call_special(&result,
937 system_instance,
938 klass,
939 vmSymbols::object_initializer_name(),
940 vmSymbols::void_method_signature(),
941 CHECK_NH);
942 }
943 Universe::set_system_thread_group(system_instance());
944
945 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
946 {
947 JavaValue result(T_VOID);
948 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
949 JavaCalls::call_special(&result,
950 main_instance,
951 klass,
952 vmSymbols::object_initializer_name(),
953 vmSymbols::threadgroup_string_void_signature(),
954 system_instance,
955 string,
956 CHECK_NH);
957 }
958 return main_instance;
959 }
960
961 // Creates the initial Thread
962 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
963 TRAPS) {
964 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
965 instanceKlassHandle klass (THREAD, k);
966 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
967
968 java_lang_Thread::set_thread(thread_oop(), thread);
969 java_lang_Thread::set_priority(thread_oop(), NormPriority);
970 thread->set_threadObj(thread_oop());
971
972 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
973
974 JavaValue result(T_VOID);
975 JavaCalls::call_special(&result, thread_oop,
976 klass,
977 vmSymbols::object_initializer_name(),
978 vmSymbols::threadgroup_string_void_signature(),
979 thread_group,
980 string,
981 CHECK_NULL);
982 return thread_oop();
983 }
984
985 static void call_initializeSystemClass(TRAPS) {
986 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
987 instanceKlassHandle klass (THREAD, k);
988
989 JavaValue result(T_VOID);
990 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
991 vmSymbols::void_method_signature(), CHECK);
992 }
993
994 char java_runtime_name[128] = "";
995 char java_runtime_version[128] = "";
996
997 // extract the JRE name from sun.misc.Version.java_runtime_name
998 static const char* get_java_runtime_name(TRAPS) {
999 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1000 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1001 fieldDescriptor fd;
1002 bool found = k != NULL &&
1003 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1004 vmSymbols::string_signature(), &fd);
1005 if (found) {
1006 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1007 if (name_oop == NULL) {
1008 return NULL;
1009 }
1010 const char* name = java_lang_String::as_utf8_string(name_oop,
1011 java_runtime_name,
1012 sizeof(java_runtime_name));
1013 return name;
1014 } else {
1015 return NULL;
1016 }
1017 }
1018
1019 // extract the JRE version from sun.misc.Version.java_runtime_version
1020 static const char* get_java_runtime_version(TRAPS) {
1021 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1022 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1023 fieldDescriptor fd;
1024 bool found = k != NULL &&
1025 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1026 vmSymbols::string_signature(), &fd);
1027 if (found) {
1028 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1029 if (name_oop == NULL) {
1030 return NULL;
1031 }
1032 const char* name = java_lang_String::as_utf8_string(name_oop,
1033 java_runtime_version,
1034 sizeof(java_runtime_version));
1035 return name;
1036 } else {
1037 return NULL;
1038 }
1039 }
1040
1041 // General purpose hook into Java code, run once when the VM is initialized.
1042 // The Java library method itself may be changed independently from the VM.
1043 static void call_postVMInitHook(TRAPS) {
1044 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1045 instanceKlassHandle klass (THREAD, k);
1046 if (klass.not_null()) {
1047 JavaValue result(T_VOID);
1048 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1049 vmSymbols::void_method_signature(),
1050 CHECK);
1051 }
1052 }
1053
1054 static void reset_vm_info_property(TRAPS) {
1055 // the vm info string
1056 ResourceMark rm(THREAD);
1057 const char *vm_info = VM_Version::vm_info_string();
1058
1059 // java.lang.System class
1060 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1061 instanceKlassHandle klass (THREAD, k);
1062
1063 // setProperty arguments
1064 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1065 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1066
1067 // return value
1068 JavaValue r(T_OBJECT);
1069
1070 // public static String setProperty(String key, String value);
1071 JavaCalls::call_static(&r,
1072 klass,
1073 vmSymbols::setProperty_name(),
1074 vmSymbols::string_string_string_signature(),
1075 key_str,
1076 value_str,
1077 CHECK);
1078 }
1079
1080
1081 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1082 bool daemon, TRAPS) {
1083 assert(thread_group.not_null(), "thread group should be specified");
1084 assert(threadObj() == NULL, "should only create Java thread object once");
1085
1086 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1087 instanceKlassHandle klass (THREAD, k);
1088 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1089
1090 java_lang_Thread::set_thread(thread_oop(), this);
1091 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1092 set_threadObj(thread_oop());
1093
1094 JavaValue result(T_VOID);
1095 if (thread_name != NULL) {
1096 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1097 // Thread gets assigned specified name and null target
1098 JavaCalls::call_special(&result,
1099 thread_oop,
1100 klass,
1101 vmSymbols::object_initializer_name(),
1102 vmSymbols::threadgroup_string_void_signature(),
1103 thread_group, // Argument 1
1104 name, // Argument 2
1105 THREAD);
1106 } else {
1107 // Thread gets assigned name "Thread-nnn" and null target
1108 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1109 JavaCalls::call_special(&result,
1110 thread_oop,
1111 klass,
1112 vmSymbols::object_initializer_name(),
1113 vmSymbols::threadgroup_runnable_void_signature(),
1114 thread_group, // Argument 1
1115 Handle(), // Argument 2
1116 THREAD);
1117 }
1118
1119
1120 if (daemon) {
1121 java_lang_Thread::set_daemon(thread_oop());
1122 }
1123
1124 if (HAS_PENDING_EXCEPTION) {
1125 return;
1126 }
1127
1128 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1129 Handle threadObj(THREAD, this->threadObj());
1130
1131 JavaCalls::call_special(&result,
1132 thread_group,
1133 group,
1134 vmSymbols::add_method_name(),
1135 vmSymbols::thread_void_signature(),
1136 threadObj, // Arg 1
1137 THREAD);
1138 }
1139
1140 // NamedThread -- non-JavaThread subclasses with multiple
1141 // uniquely named instances should derive from this.
1142 NamedThread::NamedThread() : Thread() {
1143 _name = NULL;
1144 _processed_thread = NULL;
1145 }
1146
1147 NamedThread::~NamedThread() {
1148 if (_name != NULL) {
1149 FREE_C_HEAP_ARRAY(char, _name);
1150 _name = NULL;
1151 }
1152 }
1153
1154 void NamedThread::set_name(const char* format, ...) {
1155 guarantee(_name == NULL, "Only get to set name once.");
1156 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1157 guarantee(_name != NULL, "alloc failure");
1158 va_list ap;
1159 va_start(ap, format);
1160 jio_vsnprintf(_name, max_name_len, format, ap);
1161 va_end(ap);
1162 }
1163
1164 void NamedThread::initialize_named_thread() {
1165 set_native_thread_name(name());
1166 }
1167
1168 void NamedThread::print_on(outputStream* st) const {
1169 st->print("\"%s\" ", name());
1170 Thread::print_on(st);
1171 st->cr();
1172 }
1173
1174
1175 // ======= WatcherThread ========
1176
1177 // The watcher thread exists to simulate timer interrupts. It should
1178 // be replaced by an abstraction over whatever native support for
1179 // timer interrupts exists on the platform.
1180
1181 WatcherThread* WatcherThread::_watcher_thread = NULL;
1182 bool WatcherThread::_startable = false;
1183 volatile bool WatcherThread::_should_terminate = false;
1184
1185 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1186 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1187 if (os::create_thread(this, os::watcher_thread)) {
1188 _watcher_thread = this;
1189
1190 // Set the watcher thread to the highest OS priority which should not be
1191 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1192 // is created. The only normal thread using this priority is the reference
1193 // handler thread, which runs for very short intervals only.
1194 // If the VMThread's priority is not lower than the WatcherThread profiling
1195 // will be inaccurate.
1196 os::set_priority(this, MaxPriority);
1197 if (!DisableStartThread) {
1198 os::start_thread(this);
1199 }
1200 }
1201 }
1202
1203 int WatcherThread::sleep() const {
1204 // The WatcherThread does not participate in the safepoint protocol
1205 // for the PeriodicTask_lock because it is not a JavaThread.
1206 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1207
1208 if (_should_terminate) {
1209 // check for termination before we do any housekeeping or wait
1210 return 0; // we did not sleep.
1211 }
1212
1213 // remaining will be zero if there are no tasks,
1214 // causing the WatcherThread to sleep until a task is
1215 // enrolled
1216 int remaining = PeriodicTask::time_to_wait();
1217 int time_slept = 0;
1218
1219 // we expect this to timeout - we only ever get unparked when
1220 // we should terminate or when a new task has been enrolled
1221 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1222
1223 jlong time_before_loop = os::javaTimeNanos();
1224
1225 while (true) {
1226 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1227 remaining);
1228 jlong now = os::javaTimeNanos();
1229
1230 if (remaining == 0) {
1231 // if we didn't have any tasks we could have waited for a long time
1232 // consider the time_slept zero and reset time_before_loop
1233 time_slept = 0;
1234 time_before_loop = now;
1235 } else {
1236 // need to recalculate since we might have new tasks in _tasks
1237 time_slept = (int) ((now - time_before_loop) / 1000000);
1238 }
1239
1240 // Change to task list or spurious wakeup of some kind
1241 if (timedout || _should_terminate) {
1242 break;
1243 }
1244
1245 remaining = PeriodicTask::time_to_wait();
1246 if (remaining == 0) {
1247 // Last task was just disenrolled so loop around and wait until
1248 // another task gets enrolled
1249 continue;
1250 }
1251
1252 remaining -= time_slept;
1253 if (remaining <= 0) {
1254 break;
1255 }
1256 }
1257
1258 return time_slept;
1259 }
1260
1261 void WatcherThread::run() {
1262 assert(this == watcher_thread(), "just checking");
1263
1264 this->record_stack_base_and_size();
1265 this->initialize_thread_local_storage();
1266 this->set_native_thread_name(this->name());
1267 this->set_active_handles(JNIHandleBlock::allocate_block());
1268 while (true) {
1269 assert(watcher_thread() == Thread::current(), "thread consistency check");
1270 assert(watcher_thread() == this, "thread consistency check");
1271
1272 // Calculate how long it'll be until the next PeriodicTask work
1273 // should be done, and sleep that amount of time.
1274 int time_waited = sleep();
1275
1276 if (is_error_reported()) {
1277 // A fatal error has happened, the error handler(VMError::report_and_die)
1278 // should abort JVM after creating an error log file. However in some
1279 // rare cases, the error handler itself might deadlock. Here we try to
1280 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1281 //
1282 // This code is in WatcherThread because WatcherThread wakes up
1283 // periodically so the fatal error handler doesn't need to do anything;
1284 // also because the WatcherThread is less likely to crash than other
1285 // threads.
1286
1287 for (;;) {
1288 if (!ShowMessageBoxOnError
1289 && (OnError == NULL || OnError[0] == '\0')
1290 && Arguments::abort_hook() == NULL) {
1291 os::sleep(this, 2 * 60 * 1000, false);
1292 fdStream err(defaultStream::output_fd());
1293 err.print_raw_cr("# [ timer expired, abort... ]");
1294 // skip atexit/vm_exit/vm_abort hooks
1295 os::die();
1296 }
1297
1298 // Wake up 5 seconds later, the fatal handler may reset OnError or
1299 // ShowMessageBoxOnError when it is ready to abort.
1300 os::sleep(this, 5 * 1000, false);
1301 }
1302 }
1303
1304 if (_should_terminate) {
1305 // check for termination before posting the next tick
1306 break;
1307 }
1308
1309 PeriodicTask::real_time_tick(time_waited);
1310 }
1311
1312 // Signal that it is terminated
1313 {
1314 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1315 _watcher_thread = NULL;
1316 Terminator_lock->notify();
1317 }
1318
1319 // Thread destructor usually does this..
1320 ThreadLocalStorage::set_thread(NULL);
1321 }
1322
1323 void WatcherThread::start() {
1324 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1325
1326 if (watcher_thread() == NULL && _startable) {
1327 _should_terminate = false;
1328 // Create the single instance of WatcherThread
1329 new WatcherThread();
1330 }
1331 }
1332
1333 void WatcherThread::make_startable() {
1334 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1335 _startable = true;
1336 }
1337
1338 void WatcherThread::stop() {
1339 {
1340 // Follow normal safepoint aware lock enter protocol since the
1341 // WatcherThread is stopped by another JavaThread.
1342 MutexLocker ml(PeriodicTask_lock);
1343 _should_terminate = true;
1344
1345 WatcherThread* watcher = watcher_thread();
1346 if (watcher != NULL) {
1347 // unpark the WatcherThread so it can see that it should terminate
1348 watcher->unpark();
1349 }
1350 }
1351
1352 MutexLocker mu(Terminator_lock);
1353
1354 while (watcher_thread() != NULL) {
1355 // This wait should make safepoint checks, wait without a timeout,
1356 // and wait as a suspend-equivalent condition.
1357 //
1358 // Note: If the FlatProfiler is running, then this thread is waiting
1359 // for the WatcherThread to terminate and the WatcherThread, via the
1360 // FlatProfiler task, is waiting for the external suspend request on
1361 // this thread to complete. wait_for_ext_suspend_completion() will
1362 // eventually timeout, but that takes time. Making this wait a
1363 // suspend-equivalent condition solves that timeout problem.
1364 //
1365 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1366 Mutex::_as_suspend_equivalent_flag);
1367 }
1368 }
1369
1370 void WatcherThread::unpark() {
1371 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1372 PeriodicTask_lock->notify();
1373 }
1374
1375 void WatcherThread::print_on(outputStream* st) const {
1376 st->print("\"%s\" ", name());
1377 Thread::print_on(st);
1378 st->cr();
1379 }
1380
1381 // ======= JavaThread ========
1382
1383 // A JavaThread is a normal Java thread
1384
1385 void JavaThread::initialize() {
1386 // Initialize fields
1387
1388 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1389 set_claimed_par_id(UINT_MAX);
1390
1391 set_saved_exception_pc(NULL);
1392 set_threadObj(NULL);
1393 _anchor.clear();
1394 set_entry_point(NULL);
1395 set_jni_functions(jni_functions());
1396 set_callee_target(NULL);
1397 set_vm_result(NULL);
1398 set_vm_result_2(NULL);
1399 set_vframe_array_head(NULL);
1400 set_vframe_array_last(NULL);
1401 set_deferred_locals(NULL);
1402 set_deopt_mark(NULL);
1403 set_deopt_nmethod(NULL);
1404 clear_must_deopt_id();
1405 set_monitor_chunks(NULL);
1406 set_next(NULL);
1407 set_thread_state(_thread_new);
1408 _terminated = _not_terminated;
1409 _privileged_stack_top = NULL;
1410 _array_for_gc = NULL;
1411 _suspend_equivalent = false;
1412 _in_deopt_handler = 0;
1413 _doing_unsafe_access = false;
1414 _stack_guard_state = stack_guard_unused;
1415 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1416 _exception_pc = 0;
1417 _exception_handler_pc = 0;
1418 _is_method_handle_return = 0;
1419 _jvmti_thread_state= NULL;
1420 _should_post_on_exceptions_flag = JNI_FALSE;
1421 _jvmti_get_loaded_classes_closure = NULL;
1422 _interp_only_mode = 0;
1423 _special_runtime_exit_condition = _no_async_condition;
1424 _pending_async_exception = NULL;
1425 _thread_stat = NULL;
1426 _thread_stat = new ThreadStatistics();
1427 _blocked_on_compilation = false;
1428 _jni_active_critical = 0;
1429 _pending_jni_exception_check_fn = NULL;
1430 _do_not_unlock_if_synchronized = false;
1431 _cached_monitor_info = NULL;
1432 _parker = Parker::Allocate(this);
1433
1434 #ifndef PRODUCT
1435 _jmp_ring_index = 0;
1436 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1437 record_jump(NULL, NULL, NULL, 0);
1438 }
1439 #endif // PRODUCT
1440
1441 set_thread_profiler(NULL);
1442 if (FlatProfiler::is_active()) {
1443 // This is where we would decide to either give each thread it's own profiler
1444 // or use one global one from FlatProfiler,
1445 // or up to some count of the number of profiled threads, etc.
1446 ThreadProfiler* pp = new ThreadProfiler();
1447 pp->engage();
1448 set_thread_profiler(pp);
1449 }
1450
1451 // Setup safepoint state info for this thread
1452 ThreadSafepointState::create(this);
1453
1454 debug_only(_java_call_counter = 0);
1455
1456 // JVMTI PopFrame support
1457 _popframe_condition = popframe_inactive;
1458 _popframe_preserved_args = NULL;
1459 _popframe_preserved_args_size = 0;
1460 _frames_to_pop_failed_realloc = 0;
1461
1462 pd_initialize();
1463 }
1464
1465 #if INCLUDE_ALL_GCS
1466 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1467 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1468 #endif // INCLUDE_ALL_GCS
1469
1470 JavaThread::JavaThread(bool is_attaching_via_jni) :
1471 Thread()
1472 #if INCLUDE_ALL_GCS
1473 , _satb_mark_queue(&_satb_mark_queue_set),
1474 _dirty_card_queue(&_dirty_card_queue_set)
1475 #endif // INCLUDE_ALL_GCS
1476 {
1477 initialize();
1478 if (is_attaching_via_jni) {
1479 _jni_attach_state = _attaching_via_jni;
1480 } else {
1481 _jni_attach_state = _not_attaching_via_jni;
1482 }
1483 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1484 }
1485
1486 bool JavaThread::reguard_stack(address cur_sp) {
1487 if (_stack_guard_state != stack_guard_yellow_disabled) {
1488 return true; // Stack already guarded or guard pages not needed.
1489 }
1490
1491 if (register_stack_overflow()) {
1492 // For those architectures which have separate register and
1493 // memory stacks, we must check the register stack to see if
1494 // it has overflowed.
1495 return false;
1496 }
1497
1498 // Java code never executes within the yellow zone: the latter is only
1499 // there to provoke an exception during stack banging. If java code
1500 // is executing there, either StackShadowPages should be larger, or
1501 // some exception code in c1, c2 or the interpreter isn't unwinding
1502 // when it should.
1503 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1504
1505 enable_stack_yellow_zone();
1506 return true;
1507 }
1508
1509 bool JavaThread::reguard_stack(void) {
1510 return reguard_stack(os::current_stack_pointer());
1511 }
1512
1513
1514 void JavaThread::block_if_vm_exited() {
1515 if (_terminated == _vm_exited) {
1516 // _vm_exited is set at safepoint, and Threads_lock is never released
1517 // we will block here forever
1518 Threads_lock->lock_without_safepoint_check();
1519 ShouldNotReachHere();
1520 }
1521 }
1522
1523
1524 // Remove this ifdef when C1 is ported to the compiler interface.
1525 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1526 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1527
1528 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1529 Thread()
1530 #if INCLUDE_ALL_GCS
1531 , _satb_mark_queue(&_satb_mark_queue_set),
1532 _dirty_card_queue(&_dirty_card_queue_set)
1533 #endif // INCLUDE_ALL_GCS
1534 {
1535 initialize();
1536 _jni_attach_state = _not_attaching_via_jni;
1537 set_entry_point(entry_point);
1538 // Create the native thread itself.
1539 // %note runtime_23
1540 os::ThreadType thr_type = os::java_thread;
1541 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1542 os::java_thread;
1543 os::create_thread(this, thr_type, stack_sz);
1544 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1545 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1546 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1547 // the exception consists of creating the exception object & initializing it, initialization
1548 // will leave the VM via a JavaCall and then all locks must be unlocked).
1549 //
1550 // The thread is still suspended when we reach here. Thread must be explicit started
1551 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1552 // by calling Threads:add. The reason why this is not done here, is because the thread
1553 // object must be fully initialized (take a look at JVM_Start)
1554 }
1555
1556 JavaThread::~JavaThread() {
1557
1558 // JSR166 -- return the parker to the free list
1559 Parker::Release(_parker);
1560 _parker = NULL;
1561
1562 // Free any remaining previous UnrollBlock
1563 vframeArray* old_array = vframe_array_last();
1564
1565 if (old_array != NULL) {
1566 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1567 old_array->set_unroll_block(NULL);
1568 delete old_info;
1569 delete old_array;
1570 }
1571
1572 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1573 if (deferred != NULL) {
1574 // This can only happen if thread is destroyed before deoptimization occurs.
1575 assert(deferred->length() != 0, "empty array!");
1576 do {
1577 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1578 deferred->remove_at(0);
1579 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1580 delete dlv;
1581 } while (deferred->length() != 0);
1582 delete deferred;
1583 }
1584
1585 // All Java related clean up happens in exit
1586 ThreadSafepointState::destroy(this);
1587 if (_thread_profiler != NULL) delete _thread_profiler;
1588 if (_thread_stat != NULL) delete _thread_stat;
1589 }
1590
1591
1592 // The first routine called by a new Java thread
1593 void JavaThread::run() {
1594 // initialize thread-local alloc buffer related fields
1595 this->initialize_tlab();
1596
1597 // used to test validity of stack trace backs
1598 this->record_base_of_stack_pointer();
1599
1600 // Record real stack base and size.
1601 this->record_stack_base_and_size();
1602
1603 // Initialize thread local storage; set before calling MutexLocker
1604 this->initialize_thread_local_storage();
1605
1606 this->create_stack_guard_pages();
1607
1608 this->cache_global_variables();
1609
1610 // Thread is now sufficient initialized to be handled by the safepoint code as being
1611 // in the VM. Change thread state from _thread_new to _thread_in_vm
1612 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1613
1614 assert(JavaThread::current() == this, "sanity check");
1615 assert(!Thread::current()->owns_locks(), "sanity check");
1616
1617 DTRACE_THREAD_PROBE(start, this);
1618
1619 // This operation might block. We call that after all safepoint checks for a new thread has
1620 // been completed.
1621 this->set_active_handles(JNIHandleBlock::allocate_block());
1622
1623 if (JvmtiExport::should_post_thread_life()) {
1624 JvmtiExport::post_thread_start(this);
1625 }
1626
1627 EventThreadStart event;
1628 if (event.should_commit()) {
1629 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1630 event.commit();
1631 }
1632
1633 // We call another function to do the rest so we are sure that the stack addresses used
1634 // from there will be lower than the stack base just computed
1635 thread_main_inner();
1636
1637 // Note, thread is no longer valid at this point!
1638 }
1639
1640
1641 void JavaThread::thread_main_inner() {
1642 assert(JavaThread::current() == this, "sanity check");
1643 assert(this->threadObj() != NULL, "just checking");
1644
1645 // Execute thread entry point unless this thread has a pending exception
1646 // or has been stopped before starting.
1647 // Note: Due to JVM_StopThread we can have pending exceptions already!
1648 if (!this->has_pending_exception() &&
1649 !java_lang_Thread::is_stillborn(this->threadObj())) {
1650 {
1651 ResourceMark rm(this);
1652 this->set_native_thread_name(this->get_thread_name());
1653 }
1654 HandleMark hm(this);
1655 this->entry_point()(this, this);
1656 }
1657
1658 DTRACE_THREAD_PROBE(stop, this);
1659
1660 this->exit(false);
1661 delete this;
1662 }
1663
1664
1665 static void ensure_join(JavaThread* thread) {
1666 // We do not need to grap the Threads_lock, since we are operating on ourself.
1667 Handle threadObj(thread, thread->threadObj());
1668 assert(threadObj.not_null(), "java thread object must exist");
1669 ObjectLocker lock(threadObj, thread);
1670 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1671 thread->clear_pending_exception();
1672 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1673 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1674 // Clear the native thread instance - this makes isAlive return false and allows the join()
1675 // to complete once we've done the notify_all below
1676 java_lang_Thread::set_thread(threadObj(), NULL);
1677 lock.notify_all(thread);
1678 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1679 thread->clear_pending_exception();
1680 }
1681
1682
1683 // For any new cleanup additions, please check to see if they need to be applied to
1684 // cleanup_failed_attach_current_thread as well.
1685 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1686 assert(this == JavaThread::current(), "thread consistency check");
1687
1688 HandleMark hm(this);
1689 Handle uncaught_exception(this, this->pending_exception());
1690 this->clear_pending_exception();
1691 Handle threadObj(this, this->threadObj());
1692 assert(threadObj.not_null(), "Java thread object should be created");
1693
1694 if (get_thread_profiler() != NULL) {
1695 get_thread_profiler()->disengage();
1696 ResourceMark rm;
1697 get_thread_profiler()->print(get_thread_name());
1698 }
1699
1700
1701 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1702 {
1703 EXCEPTION_MARK;
1704
1705 CLEAR_PENDING_EXCEPTION;
1706 }
1707 if (!destroy_vm) {
1708 if (uncaught_exception.not_null()) {
1709 EXCEPTION_MARK;
1710 // Call method Thread.dispatchUncaughtException().
1711 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1712 JavaValue result(T_VOID);
1713 JavaCalls::call_virtual(&result,
1714 threadObj, thread_klass,
1715 vmSymbols::dispatchUncaughtException_name(),
1716 vmSymbols::throwable_void_signature(),
1717 uncaught_exception,
1718 THREAD);
1719 if (HAS_PENDING_EXCEPTION) {
1720 ResourceMark rm(this);
1721 jio_fprintf(defaultStream::error_stream(),
1722 "\nException: %s thrown from the UncaughtExceptionHandler"
1723 " in thread \"%s\"\n",
1724 pending_exception()->klass()->external_name(),
1725 get_thread_name());
1726 CLEAR_PENDING_EXCEPTION;
1727 }
1728 }
1729
1730 // Called before the java thread exit since we want to read info
1731 // from java_lang_Thread object
1732 EventThreadEnd event;
1733 if (event.should_commit()) {
1734 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1735 event.commit();
1736 }
1737
1738 // Call after last event on thread
1739 EVENT_THREAD_EXIT(this);
1740
1741 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1742 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1743 // is deprecated anyhow.
1744 if (!is_Compiler_thread()) {
1745 int count = 3;
1746 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1747 EXCEPTION_MARK;
1748 JavaValue result(T_VOID);
1749 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1750 JavaCalls::call_virtual(&result,
1751 threadObj, thread_klass,
1752 vmSymbols::exit_method_name(),
1753 vmSymbols::void_method_signature(),
1754 THREAD);
1755 CLEAR_PENDING_EXCEPTION;
1756 }
1757 }
1758 // notify JVMTI
1759 if (JvmtiExport::should_post_thread_life()) {
1760 JvmtiExport::post_thread_end(this);
1761 }
1762
1763 // We have notified the agents that we are exiting, before we go on,
1764 // we must check for a pending external suspend request and honor it
1765 // in order to not surprise the thread that made the suspend request.
1766 while (true) {
1767 {
1768 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1769 if (!is_external_suspend()) {
1770 set_terminated(_thread_exiting);
1771 ThreadService::current_thread_exiting(this);
1772 break;
1773 }
1774 // Implied else:
1775 // Things get a little tricky here. We have a pending external
1776 // suspend request, but we are holding the SR_lock so we
1777 // can't just self-suspend. So we temporarily drop the lock
1778 // and then self-suspend.
1779 }
1780
1781 ThreadBlockInVM tbivm(this);
1782 java_suspend_self();
1783
1784 // We're done with this suspend request, but we have to loop around
1785 // and check again. Eventually we will get SR_lock without a pending
1786 // external suspend request and will be able to mark ourselves as
1787 // exiting.
1788 }
1789 // no more external suspends are allowed at this point
1790 } else {
1791 // before_exit() has already posted JVMTI THREAD_END events
1792 }
1793
1794 // Notify waiters on thread object. This has to be done after exit() is called
1795 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1796 // group should have the destroyed bit set before waiters are notified).
1797 ensure_join(this);
1798 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1799
1800 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1801 // held by this thread must be released. A detach operation must only
1802 // get here if there are no Java frames on the stack. Therefore, any
1803 // owned monitors at this point MUST be JNI-acquired monitors which are
1804 // pre-inflated and in the monitor cache.
1805 //
1806 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1807 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1808 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1809 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1810 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1811 }
1812
1813 // These things needs to be done while we are still a Java Thread. Make sure that thread
1814 // is in a consistent state, in case GC happens
1815 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1816
1817 if (active_handles() != NULL) {
1818 JNIHandleBlock* block = active_handles();
1819 set_active_handles(NULL);
1820 JNIHandleBlock::release_block(block);
1821 }
1822
1823 if (free_handle_block() != NULL) {
1824 JNIHandleBlock* block = free_handle_block();
1825 set_free_handle_block(NULL);
1826 JNIHandleBlock::release_block(block);
1827 }
1828
1829 // These have to be removed while this is still a valid thread.
1830 remove_stack_guard_pages();
1831
1832 if (UseTLAB) {
1833 tlab().make_parsable(true); // retire TLAB
1834 }
1835
1836 if (JvmtiEnv::environments_might_exist()) {
1837 JvmtiExport::cleanup_thread(this);
1838 }
1839
1840 // We must flush any deferred card marks before removing a thread from
1841 // the list of active threads.
1842 Universe::heap()->flush_deferred_store_barrier(this);
1843 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1844
1845 #if INCLUDE_ALL_GCS
1846 // We must flush the G1-related buffers before removing a thread
1847 // from the list of active threads. We must do this after any deferred
1848 // card marks have been flushed (above) so that any entries that are
1849 // added to the thread's dirty card queue as a result are not lost.
1850 if (UseG1GC) {
1851 flush_barrier_queues();
1852 }
1853 #endif // INCLUDE_ALL_GCS
1854
1855 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1856 Threads::remove(this);
1857 }
1858
1859 #if INCLUDE_ALL_GCS
1860 // Flush G1-related queues.
1861 void JavaThread::flush_barrier_queues() {
1862 satb_mark_queue().flush();
1863 dirty_card_queue().flush();
1864 }
1865
1866 void JavaThread::initialize_queues() {
1867 assert(!SafepointSynchronize::is_at_safepoint(),
1868 "we should not be at a safepoint");
1869
1870 ObjPtrQueue& satb_queue = satb_mark_queue();
1871 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1872 // The SATB queue should have been constructed with its active
1873 // field set to false.
1874 assert(!satb_queue.is_active(), "SATB queue should not be active");
1875 assert(satb_queue.is_empty(), "SATB queue should be empty");
1876 // If we are creating the thread during a marking cycle, we should
1877 // set the active field of the SATB queue to true.
1878 if (satb_queue_set.is_active()) {
1879 satb_queue.set_active(true);
1880 }
1881
1882 DirtyCardQueue& dirty_queue = dirty_card_queue();
1883 // The dirty card queue should have been constructed with its
1884 // active field set to true.
1885 assert(dirty_queue.is_active(), "dirty card queue should be active");
1886 }
1887 #endif // INCLUDE_ALL_GCS
1888
1889 void JavaThread::cleanup_failed_attach_current_thread() {
1890 if (get_thread_profiler() != NULL) {
1891 get_thread_profiler()->disengage();
1892 ResourceMark rm;
1893 get_thread_profiler()->print(get_thread_name());
1894 }
1895
1896 if (active_handles() != NULL) {
1897 JNIHandleBlock* block = active_handles();
1898 set_active_handles(NULL);
1899 JNIHandleBlock::release_block(block);
1900 }
1901
1902 if (free_handle_block() != NULL) {
1903 JNIHandleBlock* block = free_handle_block();
1904 set_free_handle_block(NULL);
1905 JNIHandleBlock::release_block(block);
1906 }
1907
1908 // These have to be removed while this is still a valid thread.
1909 remove_stack_guard_pages();
1910
1911 if (UseTLAB) {
1912 tlab().make_parsable(true); // retire TLAB, if any
1913 }
1914
1915 #if INCLUDE_ALL_GCS
1916 if (UseG1GC) {
1917 flush_barrier_queues();
1918 }
1919 #endif // INCLUDE_ALL_GCS
1920
1921 Threads::remove(this);
1922 delete this;
1923 }
1924
1925
1926
1927
1928 JavaThread* JavaThread::active() {
1929 Thread* thread = ThreadLocalStorage::thread();
1930 assert(thread != NULL, "just checking");
1931 if (thread->is_Java_thread()) {
1932 return (JavaThread*) thread;
1933 } else {
1934 assert(thread->is_VM_thread(), "this must be a vm thread");
1935 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1936 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1937 assert(ret->is_Java_thread(), "must be a Java thread");
1938 return ret;
1939 }
1940 }
1941
1942 bool JavaThread::is_lock_owned(address adr) const {
1943 if (Thread::is_lock_owned(adr)) return true;
1944
1945 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1946 if (chunk->contains(adr)) return true;
1947 }
1948
1949 return false;
1950 }
1951
1952
1953 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1954 chunk->set_next(monitor_chunks());
1955 set_monitor_chunks(chunk);
1956 }
1957
1958 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1959 guarantee(monitor_chunks() != NULL, "must be non empty");
1960 if (monitor_chunks() == chunk) {
1961 set_monitor_chunks(chunk->next());
1962 } else {
1963 MonitorChunk* prev = monitor_chunks();
1964 while (prev->next() != chunk) prev = prev->next();
1965 prev->set_next(chunk->next());
1966 }
1967 }
1968
1969 // JVM support.
1970
1971 // Note: this function shouldn't block if it's called in
1972 // _thread_in_native_trans state (such as from
1973 // check_special_condition_for_native_trans()).
1974 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1975
1976 if (has_last_Java_frame() && has_async_condition()) {
1977 // If we are at a polling page safepoint (not a poll return)
1978 // then we must defer async exception because live registers
1979 // will be clobbered by the exception path. Poll return is
1980 // ok because the call we a returning from already collides
1981 // with exception handling registers and so there is no issue.
1982 // (The exception handling path kills call result registers but
1983 // this is ok since the exception kills the result anyway).
1984
1985 if (is_at_poll_safepoint()) {
1986 // if the code we are returning to has deoptimized we must defer
1987 // the exception otherwise live registers get clobbered on the
1988 // exception path before deoptimization is able to retrieve them.
1989 //
1990 RegisterMap map(this, false);
1991 frame caller_fr = last_frame().sender(&map);
1992 assert(caller_fr.is_compiled_frame(), "what?");
1993 if (caller_fr.is_deoptimized_frame()) {
1994 if (TraceExceptions) {
1995 ResourceMark rm;
1996 tty->print_cr("deferred async exception at compiled safepoint");
1997 }
1998 return;
1999 }
2000 }
2001 }
2002
2003 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2004 if (condition == _no_async_condition) {
2005 // Conditions have changed since has_special_runtime_exit_condition()
2006 // was called:
2007 // - if we were here only because of an external suspend request,
2008 // then that was taken care of above (or cancelled) so we are done
2009 // - if we were here because of another async request, then it has
2010 // been cleared between the has_special_runtime_exit_condition()
2011 // and now so again we are done
2012 return;
2013 }
2014
2015 // Check for pending async. exception
2016 if (_pending_async_exception != NULL) {
2017 // Only overwrite an already pending exception, if it is not a threadDeath.
2018 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2019
2020 // We cannot call Exceptions::_throw(...) here because we cannot block
2021 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2022
2023 if (TraceExceptions) {
2024 ResourceMark rm;
2025 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2026 if (has_last_Java_frame()) {
2027 frame f = last_frame();
2028 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2029 }
2030 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2031 }
2032 _pending_async_exception = NULL;
2033 clear_has_async_exception();
2034 }
2035 }
2036
2037 if (check_unsafe_error &&
2038 condition == _async_unsafe_access_error && !has_pending_exception()) {
2039 condition = _no_async_condition; // done
2040 switch (thread_state()) {
2041 case _thread_in_vm: {
2042 JavaThread* THREAD = this;
2043 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2044 }
2045 case _thread_in_native: {
2046 ThreadInVMfromNative tiv(this);
2047 JavaThread* THREAD = this;
2048 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2049 }
2050 case _thread_in_Java: {
2051 ThreadInVMfromJava tiv(this);
2052 JavaThread* THREAD = this;
2053 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2054 }
2055 default:
2056 ShouldNotReachHere();
2057 }
2058 }
2059
2060 assert(condition == _no_async_condition || has_pending_exception() ||
2061 (!check_unsafe_error && condition == _async_unsafe_access_error),
2062 "must have handled the async condition, if no exception");
2063 }
2064
2065 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2066 //
2067 // Check for pending external suspend. Internal suspend requests do
2068 // not use handle_special_runtime_exit_condition().
2069 // If JNIEnv proxies are allowed, don't self-suspend if the target
2070 // thread is not the current thread. In older versions of jdbx, jdbx
2071 // threads could call into the VM with another thread's JNIEnv so we
2072 // can be here operating on behalf of a suspended thread (4432884).
2073 bool do_self_suspend = is_external_suspend_with_lock();
2074 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2075 //
2076 // Because thread is external suspended the safepoint code will count
2077 // thread as at a safepoint. This can be odd because we can be here
2078 // as _thread_in_Java which would normally transition to _thread_blocked
2079 // at a safepoint. We would like to mark the thread as _thread_blocked
2080 // before calling java_suspend_self like all other callers of it but
2081 // we must then observe proper safepoint protocol. (We can't leave
2082 // _thread_blocked with a safepoint in progress). However we can be
2083 // here as _thread_in_native_trans so we can't use a normal transition
2084 // constructor/destructor pair because they assert on that type of
2085 // transition. We could do something like:
2086 //
2087 // JavaThreadState state = thread_state();
2088 // set_thread_state(_thread_in_vm);
2089 // {
2090 // ThreadBlockInVM tbivm(this);
2091 // java_suspend_self()
2092 // }
2093 // set_thread_state(_thread_in_vm_trans);
2094 // if (safepoint) block;
2095 // set_thread_state(state);
2096 //
2097 // but that is pretty messy. Instead we just go with the way the
2098 // code has worked before and note that this is the only path to
2099 // java_suspend_self that doesn't put the thread in _thread_blocked
2100 // mode.
2101
2102 frame_anchor()->make_walkable(this);
2103 java_suspend_self();
2104
2105 // We might be here for reasons in addition to the self-suspend request
2106 // so check for other async requests.
2107 }
2108
2109 if (check_asyncs) {
2110 check_and_handle_async_exceptions();
2111 }
2112 }
2113
2114 void JavaThread::send_thread_stop(oop java_throwable) {
2115 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2116 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2117 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2118
2119 // Do not throw asynchronous exceptions against the compiler thread
2120 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2121 if (is_Compiler_thread()) return;
2122
2123 {
2124 // Actually throw the Throwable against the target Thread - however
2125 // only if there is no thread death exception installed already.
2126 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2127 // If the topmost frame is a runtime stub, then we are calling into
2128 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2129 // must deoptimize the caller before continuing, as the compiled exception handler table
2130 // may not be valid
2131 if (has_last_Java_frame()) {
2132 frame f = last_frame();
2133 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2134 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2135 RegisterMap reg_map(this, UseBiasedLocking);
2136 frame compiled_frame = f.sender(®_map);
2137 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2138 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2139 }
2140 }
2141 }
2142
2143 // Set async. pending exception in thread.
2144 set_pending_async_exception(java_throwable);
2145
2146 if (TraceExceptions) {
2147 ResourceMark rm;
2148 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2149 }
2150 // for AbortVMOnException flag
2151 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2152 }
2153 }
2154
2155
2156 // Interrupt thread so it will wake up from a potential wait()
2157 Thread::interrupt(this);
2158 }
2159
2160 // External suspension mechanism.
2161 //
2162 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2163 // to any VM_locks and it is at a transition
2164 // Self-suspension will happen on the transition out of the vm.
2165 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2166 //
2167 // Guarantees on return:
2168 // + Target thread will not execute any new bytecode (that's why we need to
2169 // force a safepoint)
2170 // + Target thread will not enter any new monitors
2171 //
2172 void JavaThread::java_suspend() {
2173 { MutexLocker mu(Threads_lock);
2174 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2175 return;
2176 }
2177 }
2178
2179 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2180 if (!is_external_suspend()) {
2181 // a racing resume has cancelled us; bail out now
2182 return;
2183 }
2184
2185 // suspend is done
2186 uint32_t debug_bits = 0;
2187 // Warning: is_ext_suspend_completed() may temporarily drop the
2188 // SR_lock to allow the thread to reach a stable thread state if
2189 // it is currently in a transient thread state.
2190 if (is_ext_suspend_completed(false /* !called_by_wait */,
2191 SuspendRetryDelay, &debug_bits)) {
2192 return;
2193 }
2194 }
2195
2196 VM_ForceSafepoint vm_suspend;
2197 VMThread::execute(&vm_suspend);
2198 }
2199
2200 // Part II of external suspension.
2201 // A JavaThread self suspends when it detects a pending external suspend
2202 // request. This is usually on transitions. It is also done in places
2203 // where continuing to the next transition would surprise the caller,
2204 // e.g., monitor entry.
2205 //
2206 // Returns the number of times that the thread self-suspended.
2207 //
2208 // Note: DO NOT call java_suspend_self() when you just want to block current
2209 // thread. java_suspend_self() is the second stage of cooperative
2210 // suspension for external suspend requests and should only be used
2211 // to complete an external suspend request.
2212 //
2213 int JavaThread::java_suspend_self() {
2214 int ret = 0;
2215
2216 // we are in the process of exiting so don't suspend
2217 if (is_exiting()) {
2218 clear_external_suspend();
2219 return ret;
2220 }
2221
2222 assert(_anchor.walkable() ||
2223 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2224 "must have walkable stack");
2225
2226 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2227
2228 assert(!this->is_ext_suspended(),
2229 "a thread trying to self-suspend should not already be suspended");
2230
2231 if (this->is_suspend_equivalent()) {
2232 // If we are self-suspending as a result of the lifting of a
2233 // suspend equivalent condition, then the suspend_equivalent
2234 // flag is not cleared until we set the ext_suspended flag so
2235 // that wait_for_ext_suspend_completion() returns consistent
2236 // results.
2237 this->clear_suspend_equivalent();
2238 }
2239
2240 // A racing resume may have cancelled us before we grabbed SR_lock
2241 // above. Or another external suspend request could be waiting for us
2242 // by the time we return from SR_lock()->wait(). The thread
2243 // that requested the suspension may already be trying to walk our
2244 // stack and if we return now, we can change the stack out from under
2245 // it. This would be a "bad thing (TM)" and cause the stack walker
2246 // to crash. We stay self-suspended until there are no more pending
2247 // external suspend requests.
2248 while (is_external_suspend()) {
2249 ret++;
2250 this->set_ext_suspended();
2251
2252 // _ext_suspended flag is cleared by java_resume()
2253 while (is_ext_suspended()) {
2254 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2255 }
2256 }
2257
2258 return ret;
2259 }
2260
2261 #ifdef ASSERT
2262 // verify the JavaThread has not yet been published in the Threads::list, and
2263 // hence doesn't need protection from concurrent access at this stage
2264 void JavaThread::verify_not_published() {
2265 if (!Threads_lock->owned_by_self()) {
2266 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2267 assert(!Threads::includes(this),
2268 "java thread shouldn't have been published yet!");
2269 } else {
2270 assert(!Threads::includes(this),
2271 "java thread shouldn't have been published yet!");
2272 }
2273 }
2274 #endif
2275
2276 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2277 // progress or when _suspend_flags is non-zero.
2278 // Current thread needs to self-suspend if there is a suspend request and/or
2279 // block if a safepoint is in progress.
2280 // Async exception ISN'T checked.
2281 // Note only the ThreadInVMfromNative transition can call this function
2282 // directly and when thread state is _thread_in_native_trans
2283 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2284 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2285
2286 JavaThread *curJT = JavaThread::current();
2287 bool do_self_suspend = thread->is_external_suspend();
2288
2289 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2290
2291 // If JNIEnv proxies are allowed, don't self-suspend if the target
2292 // thread is not the current thread. In older versions of jdbx, jdbx
2293 // threads could call into the VM with another thread's JNIEnv so we
2294 // can be here operating on behalf of a suspended thread (4432884).
2295 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2296 JavaThreadState state = thread->thread_state();
2297
2298 // We mark this thread_blocked state as a suspend-equivalent so
2299 // that a caller to is_ext_suspend_completed() won't be confused.
2300 // The suspend-equivalent state is cleared by java_suspend_self().
2301 thread->set_suspend_equivalent();
2302
2303 // If the safepoint code sees the _thread_in_native_trans state, it will
2304 // wait until the thread changes to other thread state. There is no
2305 // guarantee on how soon we can obtain the SR_lock and complete the
2306 // self-suspend request. It would be a bad idea to let safepoint wait for
2307 // too long. Temporarily change the state to _thread_blocked to
2308 // let the VM thread know that this thread is ready for GC. The problem
2309 // of changing thread state is that safepoint could happen just after
2310 // java_suspend_self() returns after being resumed, and VM thread will
2311 // see the _thread_blocked state. We must check for safepoint
2312 // after restoring the state and make sure we won't leave while a safepoint
2313 // is in progress.
2314 thread->set_thread_state(_thread_blocked);
2315 thread->java_suspend_self();
2316 thread->set_thread_state(state);
2317 // Make sure new state is seen by VM thread
2318 if (os::is_MP()) {
2319 if (UseMembar) {
2320 // Force a fence between the write above and read below
2321 OrderAccess::fence();
2322 } else {
2323 // Must use this rather than serialization page in particular on Windows
2324 InterfaceSupport::serialize_memory(thread);
2325 }
2326 }
2327 }
2328
2329 if (SafepointSynchronize::do_call_back()) {
2330 // If we are safepointing, then block the caller which may not be
2331 // the same as the target thread (see above).
2332 SafepointSynchronize::block(curJT);
2333 }
2334
2335 if (thread->is_deopt_suspend()) {
2336 thread->clear_deopt_suspend();
2337 RegisterMap map(thread, false);
2338 frame f = thread->last_frame();
2339 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2340 f = f.sender(&map);
2341 }
2342 if (f.id() == thread->must_deopt_id()) {
2343 thread->clear_must_deopt_id();
2344 f.deoptimize(thread);
2345 } else {
2346 fatal("missed deoptimization!");
2347 }
2348 }
2349 }
2350
2351 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2352 // progress or when _suspend_flags is non-zero.
2353 // Current thread needs to self-suspend if there is a suspend request and/or
2354 // block if a safepoint is in progress.
2355 // Also check for pending async exception (not including unsafe access error).
2356 // Note only the native==>VM/Java barriers can call this function and when
2357 // thread state is _thread_in_native_trans.
2358 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2359 check_safepoint_and_suspend_for_native_trans(thread);
2360
2361 if (thread->has_async_exception()) {
2362 // We are in _thread_in_native_trans state, don't handle unsafe
2363 // access error since that may block.
2364 thread->check_and_handle_async_exceptions(false);
2365 }
2366 }
2367
2368 // This is a variant of the normal
2369 // check_special_condition_for_native_trans with slightly different
2370 // semantics for use by critical native wrappers. It does all the
2371 // normal checks but also performs the transition back into
2372 // thread_in_Java state. This is required so that critical natives
2373 // can potentially block and perform a GC if they are the last thread
2374 // exiting the GC_locker.
2375 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2376 check_special_condition_for_native_trans(thread);
2377
2378 // Finish the transition
2379 thread->set_thread_state(_thread_in_Java);
2380
2381 if (thread->do_critical_native_unlock()) {
2382 ThreadInVMfromJavaNoAsyncException tiv(thread);
2383 GC_locker::unlock_critical(thread);
2384 thread->clear_critical_native_unlock();
2385 }
2386 }
2387
2388 // We need to guarantee the Threads_lock here, since resumes are not
2389 // allowed during safepoint synchronization
2390 // Can only resume from an external suspension
2391 void JavaThread::java_resume() {
2392 assert_locked_or_safepoint(Threads_lock);
2393
2394 // Sanity check: thread is gone, has started exiting or the thread
2395 // was not externally suspended.
2396 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2397 return;
2398 }
2399
2400 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2401
2402 clear_external_suspend();
2403
2404 if (is_ext_suspended()) {
2405 clear_ext_suspended();
2406 SR_lock()->notify_all();
2407 }
2408 }
2409
2410 void JavaThread::create_stack_guard_pages() {
2411 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2412 address low_addr = stack_base() - stack_size();
2413 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2414
2415 int allocate = os::allocate_stack_guard_pages();
2416 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2417
2418 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2419 warning("Attempt to allocate stack guard pages failed.");
2420 return;
2421 }
2422
2423 if (os::guard_memory((char *) low_addr, len)) {
2424 _stack_guard_state = stack_guard_enabled;
2425 } else {
2426 warning("Attempt to protect stack guard pages failed.");
2427 if (os::uncommit_memory((char *) low_addr, len)) {
2428 warning("Attempt to deallocate stack guard pages failed.");
2429 }
2430 }
2431 }
2432
2433 void JavaThread::remove_stack_guard_pages() {
2434 assert(Thread::current() == this, "from different thread");
2435 if (_stack_guard_state == stack_guard_unused) return;
2436 address low_addr = stack_base() - stack_size();
2437 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2438
2439 if (os::allocate_stack_guard_pages()) {
2440 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2441 _stack_guard_state = stack_guard_unused;
2442 } else {
2443 warning("Attempt to deallocate stack guard pages failed.");
2444 }
2445 } else {
2446 if (_stack_guard_state == stack_guard_unused) return;
2447 if (os::unguard_memory((char *) low_addr, len)) {
2448 _stack_guard_state = stack_guard_unused;
2449 } else {
2450 warning("Attempt to unprotect stack guard pages failed.");
2451 }
2452 }
2453 }
2454
2455 void JavaThread::enable_stack_yellow_zone() {
2456 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2457 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2458
2459 // The base notation is from the stacks point of view, growing downward.
2460 // We need to adjust it to work correctly with guard_memory()
2461 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2462
2463 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2464 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2465
2466 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2467 _stack_guard_state = stack_guard_enabled;
2468 } else {
2469 warning("Attempt to guard stack yellow zone failed.");
2470 }
2471 enable_register_stack_guard();
2472 }
2473
2474 void JavaThread::disable_stack_yellow_zone() {
2475 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2476 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2477
2478 // Simply return if called for a thread that does not use guard pages.
2479 if (_stack_guard_state == stack_guard_unused) return;
2480
2481 // The base notation is from the stacks point of view, growing downward.
2482 // We need to adjust it to work correctly with guard_memory()
2483 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2484
2485 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2486 _stack_guard_state = stack_guard_yellow_disabled;
2487 } else {
2488 warning("Attempt to unguard stack yellow zone failed.");
2489 }
2490 disable_register_stack_guard();
2491 }
2492
2493 void JavaThread::enable_stack_red_zone() {
2494 // The base notation is from the stacks point of view, growing downward.
2495 // We need to adjust it to work correctly with guard_memory()
2496 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2497 address base = stack_red_zone_base() - stack_red_zone_size();
2498
2499 guarantee(base < stack_base(), "Error calculating stack red zone");
2500 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2501
2502 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2503 warning("Attempt to guard stack red zone failed.");
2504 }
2505 }
2506
2507 void JavaThread::disable_stack_red_zone() {
2508 // The base notation is from the stacks point of view, growing downward.
2509 // We need to adjust it to work correctly with guard_memory()
2510 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2511 address base = stack_red_zone_base() - stack_red_zone_size();
2512 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2513 warning("Attempt to unguard stack red zone failed.");
2514 }
2515 }
2516
2517 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2518 // ignore is there is no stack
2519 if (!has_last_Java_frame()) return;
2520 // traverse the stack frames. Starts from top frame.
2521 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2522 frame* fr = fst.current();
2523 f(fr, fst.register_map());
2524 }
2525 }
2526
2527
2528 #ifndef PRODUCT
2529 // Deoptimization
2530 // Function for testing deoptimization
2531 void JavaThread::deoptimize() {
2532 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2533 StackFrameStream fst(this, UseBiasedLocking);
2534 bool deopt = false; // Dump stack only if a deopt actually happens.
2535 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2536 // Iterate over all frames in the thread and deoptimize
2537 for (; !fst.is_done(); fst.next()) {
2538 if (fst.current()->can_be_deoptimized()) {
2539
2540 if (only_at) {
2541 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2542 // consists of comma or carriage return separated numbers so
2543 // search for the current bci in that string.
2544 address pc = fst.current()->pc();
2545 nmethod* nm = (nmethod*) fst.current()->cb();
2546 ScopeDesc* sd = nm->scope_desc_at(pc);
2547 char buffer[8];
2548 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2549 size_t len = strlen(buffer);
2550 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2551 while (found != NULL) {
2552 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2553 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2554 // Check that the bci found is bracketed by terminators.
2555 break;
2556 }
2557 found = strstr(found + 1, buffer);
2558 }
2559 if (!found) {
2560 continue;
2561 }
2562 }
2563
2564 if (DebugDeoptimization && !deopt) {
2565 deopt = true; // One-time only print before deopt
2566 tty->print_cr("[BEFORE Deoptimization]");
2567 trace_frames();
2568 trace_stack();
2569 }
2570 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2571 }
2572 }
2573
2574 if (DebugDeoptimization && deopt) {
2575 tty->print_cr("[AFTER Deoptimization]");
2576 trace_frames();
2577 }
2578 }
2579
2580
2581 // Make zombies
2582 void JavaThread::make_zombies() {
2583 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2584 if (fst.current()->can_be_deoptimized()) {
2585 // it is a Java nmethod
2586 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2587 nm->make_not_entrant();
2588 }
2589 }
2590 }
2591 #endif // PRODUCT
2592
2593
2594 void JavaThread::deoptimized_wrt_marked_nmethods() {
2595 if (!has_last_Java_frame()) return;
2596 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2597 StackFrameStream fst(this, UseBiasedLocking);
2598 for (; !fst.is_done(); fst.next()) {
2599 if (fst.current()->should_be_deoptimized()) {
2600 if (LogCompilation && xtty != NULL) {
2601 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2602 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2603 this->name(), nm != NULL ? nm->compile_id() : -1);
2604 }
2605
2606 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2607 }
2608 }
2609 }
2610
2611
2612 // If the caller is a NamedThread, then remember, in the current scope,
2613 // the given JavaThread in its _processed_thread field.
2614 class RememberProcessedThread: public StackObj {
2615 NamedThread* _cur_thr;
2616 public:
2617 RememberProcessedThread(JavaThread* jthr) {
2618 Thread* thread = Thread::current();
2619 if (thread->is_Named_thread()) {
2620 _cur_thr = (NamedThread *)thread;
2621 _cur_thr->set_processed_thread(jthr);
2622 } else {
2623 _cur_thr = NULL;
2624 }
2625 }
2626
2627 ~RememberProcessedThread() {
2628 if (_cur_thr) {
2629 _cur_thr->set_processed_thread(NULL);
2630 }
2631 }
2632 };
2633
2634 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2635 // Verify that the deferred card marks have been flushed.
2636 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2637
2638 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2639 // since there may be more than one thread using each ThreadProfiler.
2640
2641 // Traverse the GCHandles
2642 Thread::oops_do(f, cld_f, cf);
2643
2644 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2645 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2646
2647 if (has_last_Java_frame()) {
2648 // Record JavaThread to GC thread
2649 RememberProcessedThread rpt(this);
2650
2651 // Traverse the privileged stack
2652 if (_privileged_stack_top != NULL) {
2653 _privileged_stack_top->oops_do(f);
2654 }
2655
2656 // traverse the registered growable array
2657 if (_array_for_gc != NULL) {
2658 for (int index = 0; index < _array_for_gc->length(); index++) {
2659 f->do_oop(_array_for_gc->adr_at(index));
2660 }
2661 }
2662
2663 // Traverse the monitor chunks
2664 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2665 chunk->oops_do(f);
2666 }
2667
2668 // Traverse the execution stack
2669 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2670 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2671 }
2672 }
2673
2674 // callee_target is never live across a gc point so NULL it here should
2675 // it still contain a methdOop.
2676
2677 set_callee_target(NULL);
2678
2679 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2680 // If we have deferred set_locals there might be oops waiting to be
2681 // written
2682 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2683 if (list != NULL) {
2684 for (int i = 0; i < list->length(); i++) {
2685 list->at(i)->oops_do(f);
2686 }
2687 }
2688
2689 // Traverse instance variables at the end since the GC may be moving things
2690 // around using this function
2691 f->do_oop((oop*) &_threadObj);
2692 f->do_oop((oop*) &_vm_result);
2693 f->do_oop((oop*) &_exception_oop);
2694 f->do_oop((oop*) &_pending_async_exception);
2695
2696 if (jvmti_thread_state() != NULL) {
2697 jvmti_thread_state()->oops_do(f);
2698 }
2699 }
2700
2701 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2702 Thread::nmethods_do(cf); // (super method is a no-op)
2703
2704 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2705 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2706
2707 if (has_last_Java_frame()) {
2708 // Traverse the execution stack
2709 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2710 fst.current()->nmethods_do(cf);
2711 }
2712 }
2713 }
2714
2715 void JavaThread::metadata_do(void f(Metadata*)) {
2716 if (has_last_Java_frame()) {
2717 // Traverse the execution stack to call f() on the methods in the stack
2718 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2719 fst.current()->metadata_do(f);
2720 }
2721 } else if (is_Compiler_thread()) {
2722 // need to walk ciMetadata in current compile tasks to keep alive.
2723 CompilerThread* ct = (CompilerThread*)this;
2724 if (ct->env() != NULL) {
2725 ct->env()->metadata_do(f);
2726 }
2727 }
2728 }
2729
2730 // Printing
2731 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2732 switch (_thread_state) {
2733 case _thread_uninitialized: return "_thread_uninitialized";
2734 case _thread_new: return "_thread_new";
2735 case _thread_new_trans: return "_thread_new_trans";
2736 case _thread_in_native: return "_thread_in_native";
2737 case _thread_in_native_trans: return "_thread_in_native_trans";
2738 case _thread_in_vm: return "_thread_in_vm";
2739 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2740 case _thread_in_Java: return "_thread_in_Java";
2741 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2742 case _thread_blocked: return "_thread_blocked";
2743 case _thread_blocked_trans: return "_thread_blocked_trans";
2744 default: return "unknown thread state";
2745 }
2746 }
2747
2748 #ifndef PRODUCT
2749 void JavaThread::print_thread_state_on(outputStream *st) const {
2750 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2751 };
2752 void JavaThread::print_thread_state() const {
2753 print_thread_state_on(tty);
2754 }
2755 #endif // PRODUCT
2756
2757 // Called by Threads::print() for VM_PrintThreads operation
2758 void JavaThread::print_on(outputStream *st) const {
2759 st->print("\"%s\" ", get_thread_name());
2760 oop thread_oop = threadObj();
2761 if (thread_oop != NULL) {
2762 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2763 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2764 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2765 }
2766 Thread::print_on(st);
2767 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2768 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2769 if (thread_oop != NULL) {
2770 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2771 }
2772 #ifndef PRODUCT
2773 print_thread_state_on(st);
2774 _safepoint_state->print_on(st);
2775 #endif // PRODUCT
2776 }
2777
2778 // Called by fatal error handler. The difference between this and
2779 // JavaThread::print() is that we can't grab lock or allocate memory.
2780 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2781 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2782 oop thread_obj = threadObj();
2783 if (thread_obj != NULL) {
2784 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2785 }
2786 st->print(" [");
2787 st->print("%s", _get_thread_state_name(_thread_state));
2788 if (osthread()) {
2789 st->print(", id=%d", osthread()->thread_id());
2790 }
2791 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2792 _stack_base - _stack_size, _stack_base);
2793 st->print("]");
2794 return;
2795 }
2796
2797 // Verification
2798
2799 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2800
2801 void JavaThread::verify() {
2802 // Verify oops in the thread.
2803 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2804
2805 // Verify the stack frames.
2806 frames_do(frame_verify);
2807 }
2808
2809 // CR 6300358 (sub-CR 2137150)
2810 // Most callers of this method assume that it can't return NULL but a
2811 // thread may not have a name whilst it is in the process of attaching to
2812 // the VM - see CR 6412693, and there are places where a JavaThread can be
2813 // seen prior to having it's threadObj set (eg JNI attaching threads and
2814 // if vm exit occurs during initialization). These cases can all be accounted
2815 // for such that this method never returns NULL.
2816 const char* JavaThread::get_thread_name() const {
2817 #ifdef ASSERT
2818 // early safepoints can hit while current thread does not yet have TLS
2819 if (!SafepointSynchronize::is_at_safepoint()) {
2820 Thread *cur = Thread::current();
2821 if (!(cur->is_Java_thread() && cur == this)) {
2822 // Current JavaThreads are allowed to get their own name without
2823 // the Threads_lock.
2824 assert_locked_or_safepoint(Threads_lock);
2825 }
2826 }
2827 #endif // ASSERT
2828 return get_thread_name_string();
2829 }
2830
2831 // Returns a non-NULL representation of this thread's name, or a suitable
2832 // descriptive string if there is no set name
2833 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2834 const char* name_str;
2835 oop thread_obj = threadObj();
2836 if (thread_obj != NULL) {
2837 oop name = java_lang_Thread::name(thread_obj);
2838 if (name != NULL) {
2839 if (buf == NULL) {
2840 name_str = java_lang_String::as_utf8_string(name);
2841 } else {
2842 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2843 }
2844 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2845 name_str = "<no-name - thread is attaching>";
2846 } else {
2847 name_str = Thread::name();
2848 }
2849 } else {
2850 name_str = Thread::name();
2851 }
2852 assert(name_str != NULL, "unexpected NULL thread name");
2853 return name_str;
2854 }
2855
2856
2857 const char* JavaThread::get_threadgroup_name() const {
2858 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2859 oop thread_obj = threadObj();
2860 if (thread_obj != NULL) {
2861 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2862 if (thread_group != NULL) {
2863 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2864 // ThreadGroup.name can be null
2865 if (name != NULL) {
2866 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2867 return str;
2868 }
2869 }
2870 }
2871 return NULL;
2872 }
2873
2874 const char* JavaThread::get_parent_name() const {
2875 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2876 oop thread_obj = threadObj();
2877 if (thread_obj != NULL) {
2878 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2879 if (thread_group != NULL) {
2880 oop parent = java_lang_ThreadGroup::parent(thread_group);
2881 if (parent != NULL) {
2882 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2883 // ThreadGroup.name can be null
2884 if (name != NULL) {
2885 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2886 return str;
2887 }
2888 }
2889 }
2890 }
2891 return NULL;
2892 }
2893
2894 ThreadPriority JavaThread::java_priority() const {
2895 oop thr_oop = threadObj();
2896 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2897 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2898 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2899 return priority;
2900 }
2901
2902 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2903
2904 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2905 // Link Java Thread object <-> C++ Thread
2906
2907 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2908 // and put it into a new Handle. The Handle "thread_oop" can then
2909 // be used to pass the C++ thread object to other methods.
2910
2911 // Set the Java level thread object (jthread) field of the
2912 // new thread (a JavaThread *) to C++ thread object using the
2913 // "thread_oop" handle.
2914
2915 // Set the thread field (a JavaThread *) of the
2916 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2917
2918 Handle thread_oop(Thread::current(),
2919 JNIHandles::resolve_non_null(jni_thread));
2920 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2921 "must be initialized");
2922 set_threadObj(thread_oop());
2923 java_lang_Thread::set_thread(thread_oop(), this);
2924
2925 if (prio == NoPriority) {
2926 prio = java_lang_Thread::priority(thread_oop());
2927 assert(prio != NoPriority, "A valid priority should be present");
2928 }
2929
2930 // Push the Java priority down to the native thread; needs Threads_lock
2931 Thread::set_priority(this, prio);
2932
2933 prepare_ext();
2934
2935 // Add the new thread to the Threads list and set it in motion.
2936 // We must have threads lock in order to call Threads::add.
2937 // It is crucial that we do not block before the thread is
2938 // added to the Threads list for if a GC happens, then the java_thread oop
2939 // will not be visited by GC.
2940 Threads::add(this);
2941 }
2942
2943 oop JavaThread::current_park_blocker() {
2944 // Support for JSR-166 locks
2945 oop thread_oop = threadObj();
2946 if (thread_oop != NULL &&
2947 JDK_Version::current().supports_thread_park_blocker()) {
2948 return java_lang_Thread::park_blocker(thread_oop);
2949 }
2950 return NULL;
2951 }
2952
2953
2954 void JavaThread::print_stack_on(outputStream* st) {
2955 if (!has_last_Java_frame()) return;
2956 ResourceMark rm;
2957 HandleMark hm;
2958
2959 RegisterMap reg_map(this);
2960 vframe* start_vf = last_java_vframe(®_map);
2961 int count = 0;
2962 for (vframe* f = start_vf; f; f = f->sender()) {
2963 if (f->is_java_frame()) {
2964 javaVFrame* jvf = javaVFrame::cast(f);
2965 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2966
2967 // Print out lock information
2968 if (JavaMonitorsInStackTrace) {
2969 jvf->print_lock_info_on(st, count);
2970 }
2971 } else {
2972 // Ignore non-Java frames
2973 }
2974
2975 // Bail-out case for too deep stacks
2976 count++;
2977 if (MaxJavaStackTraceDepth == count) return;
2978 }
2979 }
2980
2981
2982 // JVMTI PopFrame support
2983 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2984 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2985 if (in_bytes(size_in_bytes) != 0) {
2986 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
2987 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2988 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2989 }
2990 }
2991
2992 void* JavaThread::popframe_preserved_args() {
2993 return _popframe_preserved_args;
2994 }
2995
2996 ByteSize JavaThread::popframe_preserved_args_size() {
2997 return in_ByteSize(_popframe_preserved_args_size);
2998 }
2999
3000 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3001 int sz = in_bytes(popframe_preserved_args_size());
3002 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3003 return in_WordSize(sz / wordSize);
3004 }
3005
3006 void JavaThread::popframe_free_preserved_args() {
3007 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3008 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3009 _popframe_preserved_args = NULL;
3010 _popframe_preserved_args_size = 0;
3011 }
3012
3013 #ifndef PRODUCT
3014
3015 void JavaThread::trace_frames() {
3016 tty->print_cr("[Describe stack]");
3017 int frame_no = 1;
3018 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3019 tty->print(" %d. ", frame_no++);
3020 fst.current()->print_value_on(tty, this);
3021 tty->cr();
3022 }
3023 }
3024
3025 class PrintAndVerifyOopClosure: public OopClosure {
3026 protected:
3027 template <class T> inline void do_oop_work(T* p) {
3028 oop obj = oopDesc::load_decode_heap_oop(p);
3029 if (obj == NULL) return;
3030 tty->print(INTPTR_FORMAT ": ", p);
3031 if (obj->is_oop_or_null()) {
3032 if (obj->is_objArray()) {
3033 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3034 } else {
3035 obj->print();
3036 }
3037 } else {
3038 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3039 }
3040 tty->cr();
3041 }
3042 public:
3043 virtual void do_oop(oop* p) { do_oop_work(p); }
3044 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3045 };
3046
3047
3048 static void oops_print(frame* f, const RegisterMap *map) {
3049 PrintAndVerifyOopClosure print;
3050 f->print_value();
3051 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3052 }
3053
3054 // Print our all the locations that contain oops and whether they are
3055 // valid or not. This useful when trying to find the oldest frame
3056 // where an oop has gone bad since the frame walk is from youngest to
3057 // oldest.
3058 void JavaThread::trace_oops() {
3059 tty->print_cr("[Trace oops]");
3060 frames_do(oops_print);
3061 }
3062
3063
3064 #ifdef ASSERT
3065 // Print or validate the layout of stack frames
3066 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3067 ResourceMark rm;
3068 PRESERVE_EXCEPTION_MARK;
3069 FrameValues values;
3070 int frame_no = 0;
3071 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3072 fst.current()->describe(values, ++frame_no);
3073 if (depth == frame_no) break;
3074 }
3075 if (validate_only) {
3076 values.validate();
3077 } else {
3078 tty->print_cr("[Describe stack layout]");
3079 values.print(this);
3080 }
3081 }
3082 #endif
3083
3084 void JavaThread::trace_stack_from(vframe* start_vf) {
3085 ResourceMark rm;
3086 int vframe_no = 1;
3087 for (vframe* f = start_vf; f; f = f->sender()) {
3088 if (f->is_java_frame()) {
3089 javaVFrame::cast(f)->print_activation(vframe_no++);
3090 } else {
3091 f->print();
3092 }
3093 if (vframe_no > StackPrintLimit) {
3094 tty->print_cr("...<more frames>...");
3095 return;
3096 }
3097 }
3098 }
3099
3100
3101 void JavaThread::trace_stack() {
3102 if (!has_last_Java_frame()) return;
3103 ResourceMark rm;
3104 HandleMark hm;
3105 RegisterMap reg_map(this);
3106 trace_stack_from(last_java_vframe(®_map));
3107 }
3108
3109
3110 #endif // PRODUCT
3111
3112
3113 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3114 assert(reg_map != NULL, "a map must be given");
3115 frame f = last_frame();
3116 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3117 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3118 }
3119 return NULL;
3120 }
3121
3122
3123 Klass* JavaThread::security_get_caller_class(int depth) {
3124 vframeStream vfst(this);
3125 vfst.security_get_caller_frame(depth);
3126 if (!vfst.at_end()) {
3127 return vfst.method()->method_holder();
3128 }
3129 return NULL;
3130 }
3131
3132 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3133 assert(thread->is_Compiler_thread(), "must be compiler thread");
3134 CompileBroker::compiler_thread_loop();
3135 }
3136
3137 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3138 NMethodSweeper::sweeper_loop();
3139 }
3140
3141 // Create a CompilerThread
3142 CompilerThread::CompilerThread(CompileQueue* queue,
3143 CompilerCounters* counters)
3144 : JavaThread(&compiler_thread_entry) {
3145 _env = NULL;
3146 _log = NULL;
3147 _task = NULL;
3148 _queue = queue;
3149 _counters = counters;
3150 _buffer_blob = NULL;
3151 _compiler = NULL;
3152
3153 #ifndef PRODUCT
3154 _ideal_graph_printer = NULL;
3155 #endif
3156 }
3157
3158 // Create sweeper thread
3159 CodeCacheSweeperThread::CodeCacheSweeperThread()
3160 : JavaThread(&sweeper_thread_entry) {
3161 _scanned_nmethod = NULL;
3162 }
3163 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3164 JavaThread::oops_do(f, cld_f, cf);
3165 if (_scanned_nmethod != NULL && cf != NULL) {
3166 // Safepoints can occur when the sweeper is scanning an nmethod so
3167 // process it here to make sure it isn't unloaded in the middle of
3168 // a scan.
3169 cf->do_code_blob(_scanned_nmethod);
3170 }
3171 }
3172
3173
3174 // ======= Threads ========
3175
3176 // The Threads class links together all active threads, and provides
3177 // operations over all threads. It is protected by its own Mutex
3178 // lock, which is also used in other contexts to protect thread
3179 // operations from having the thread being operated on from exiting
3180 // and going away unexpectedly (e.g., safepoint synchronization)
3181
3182 JavaThread* Threads::_thread_list = NULL;
3183 int Threads::_number_of_threads = 0;
3184 int Threads::_number_of_non_daemon_threads = 0;
3185 int Threads::_return_code = 0;
3186 int Threads::_thread_claim_parity = 0;
3187 size_t JavaThread::_stack_size_at_create = 0;
3188 #ifdef ASSERT
3189 bool Threads::_vm_complete = false;
3190 #endif
3191
3192 // All JavaThreads
3193 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3194
3195 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3196 void Threads::threads_do(ThreadClosure* tc) {
3197 assert_locked_or_safepoint(Threads_lock);
3198 // ALL_JAVA_THREADS iterates through all JavaThreads
3199 ALL_JAVA_THREADS(p) {
3200 tc->do_thread(p);
3201 }
3202 // Someday we could have a table or list of all non-JavaThreads.
3203 // For now, just manually iterate through them.
3204 tc->do_thread(VMThread::vm_thread());
3205 Universe::heap()->gc_threads_do(tc);
3206 WatcherThread *wt = WatcherThread::watcher_thread();
3207 // Strictly speaking, the following NULL check isn't sufficient to make sure
3208 // the data for WatcherThread is still valid upon being examined. However,
3209 // considering that WatchThread terminates when the VM is on the way to
3210 // exit at safepoint, the chance of the above is extremely small. The right
3211 // way to prevent termination of WatcherThread would be to acquire
3212 // Terminator_lock, but we can't do that without violating the lock rank
3213 // checking in some cases.
3214 if (wt != NULL) {
3215 tc->do_thread(wt);
3216 }
3217
3218 // If CompilerThreads ever become non-JavaThreads, add them here
3219 }
3220
3221 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3222 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3223
3224 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3225 create_vm_init_libraries();
3226 }
3227
3228 initialize_class(vmSymbols::java_lang_String(), CHECK);
3229
3230 // Initialize java_lang.System (needed before creating the thread)
3231 initialize_class(vmSymbols::java_lang_System(), CHECK);
3232 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3233 Handle thread_group = create_initial_thread_group(CHECK);
3234 Universe::set_main_thread_group(thread_group());
3235 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3236 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3237 main_thread->set_threadObj(thread_object);
3238 // Set thread status to running since main thread has
3239 // been started and running.
3240 java_lang_Thread::set_thread_status(thread_object,
3241 java_lang_Thread::RUNNABLE);
3242
3243 // The VM creates & returns objects of this class. Make sure it's initialized.
3244 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3245
3246 // The VM preresolves methods to these classes. Make sure that they get initialized
3247 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3248 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3249 call_initializeSystemClass(CHECK);
3250
3251 // get the Java runtime name after java.lang.System is initialized
3252 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3253 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3254
3255 // an instance of OutOfMemory exception has been allocated earlier
3256 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3257 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3258 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3259 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3260 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3261 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3262 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3263 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3264 }
3265
3266 void Threads::initialize_jsr292_core_classes(TRAPS) {
3267 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3268 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3269 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3270 }
3271
3272 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3273 extern void JDK_Version_init();
3274
3275 // Check version
3276 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3277
3278 // Initialize the output stream module
3279 ostream_init();
3280
3281 // Process java launcher properties.
3282 Arguments::process_sun_java_launcher_properties(args);
3283
3284 // Initialize the os module before using TLS
3285 os::init();
3286
3287 // Initialize system properties.
3288 Arguments::init_system_properties();
3289
3290 // So that JDK version can be used as a discriminator when parsing arguments
3291 JDK_Version_init();
3292
3293 // Update/Initialize System properties after JDK version number is known
3294 Arguments::init_version_specific_system_properties();
3295
3296 // Parse arguments
3297 jint parse_result = Arguments::parse(args);
3298 if (parse_result != JNI_OK) return parse_result;
3299
3300 os::init_before_ergo();
3301
3302 jint ergo_result = Arguments::apply_ergo();
3303 if (ergo_result != JNI_OK) return ergo_result;
3304
3305 if (PauseAtStartup) {
3306 os::pause();
3307 }
3308
3309 HOTSPOT_VM_INIT_BEGIN();
3310
3311 // Record VM creation timing statistics
3312 TraceVmCreationTime create_vm_timer;
3313 create_vm_timer.start();
3314
3315 // Timing (must come after argument parsing)
3316 TraceTime timer("Create VM", TraceStartupTime);
3317
3318 // Initialize the os module after parsing the args
3319 jint os_init_2_result = os::init_2();
3320 if (os_init_2_result != JNI_OK) return os_init_2_result;
3321
3322 jint adjust_after_os_result = Arguments::adjust_after_os();
3323 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3324
3325 // initialize TLS
3326 ThreadLocalStorage::init();
3327
3328 // Initialize output stream logging
3329 ostream_init_log();
3330
3331 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3332 // Must be before create_vm_init_agents()
3333 if (Arguments::init_libraries_at_startup()) {
3334 convert_vm_init_libraries_to_agents();
3335 }
3336
3337 // Launch -agentlib/-agentpath and converted -Xrun agents
3338 if (Arguments::init_agents_at_startup()) {
3339 create_vm_init_agents();
3340 }
3341
3342 // Initialize Threads state
3343 _thread_list = NULL;
3344 _number_of_threads = 0;
3345 _number_of_non_daemon_threads = 0;
3346
3347 // Initialize global data structures and create system classes in heap
3348 vm_init_globals();
3349
3350 // Attach the main thread to this os thread
3351 JavaThread* main_thread = new JavaThread();
3352 main_thread->set_thread_state(_thread_in_vm);
3353 // must do this before set_active_handles and initialize_thread_local_storage
3354 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3355 // change the stack size recorded here to one based on the java thread
3356 // stacksize. This adjusted size is what is used to figure the placement
3357 // of the guard pages.
3358 main_thread->record_stack_base_and_size();
3359 main_thread->initialize_thread_local_storage();
3360
3361 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3362
3363 if (!main_thread->set_as_starting_thread()) {
3364 vm_shutdown_during_initialization(
3365 "Failed necessary internal allocation. Out of swap space");
3366 delete main_thread;
3367 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3368 return JNI_ENOMEM;
3369 }
3370
3371 // Enable guard page *after* os::create_main_thread(), otherwise it would
3372 // crash Linux VM, see notes in os_linux.cpp.
3373 main_thread->create_stack_guard_pages();
3374
3375 // Initialize Java-Level synchronization subsystem
3376 ObjectMonitor::Initialize();
3377
3378 // Initialize global modules
3379 jint status = init_globals();
3380 if (status != JNI_OK) {
3381 delete main_thread;
3382 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3383 return status;
3384 }
3385
3386 // Should be done after the heap is fully created
3387 main_thread->cache_global_variables();
3388
3389 HandleMark hm;
3390
3391 { MutexLocker mu(Threads_lock);
3392 Threads::add(main_thread);
3393 }
3394
3395 // Any JVMTI raw monitors entered in onload will transition into
3396 // real raw monitor. VM is setup enough here for raw monitor enter.
3397 JvmtiExport::transition_pending_onload_raw_monitors();
3398
3399 // Create the VMThread
3400 { TraceTime timer("Start VMThread", TraceStartupTime);
3401 VMThread::create();
3402 Thread* vmthread = VMThread::vm_thread();
3403
3404 if (!os::create_thread(vmthread, os::vm_thread)) {
3405 vm_exit_during_initialization("Cannot create VM thread. "
3406 "Out of system resources.");
3407 }
3408
3409 // Wait for the VM thread to become ready, and VMThread::run to initialize
3410 // Monitors can have spurious returns, must always check another state flag
3411 {
3412 MutexLocker ml(Notify_lock);
3413 os::start_thread(vmthread);
3414 while (vmthread->active_handles() == NULL) {
3415 Notify_lock->wait();
3416 }
3417 }
3418 }
3419
3420 assert(Universe::is_fully_initialized(), "not initialized");
3421 if (VerifyDuringStartup) {
3422 // Make sure we're starting with a clean slate.
3423 VM_Verify verify_op;
3424 VMThread::execute(&verify_op);
3425 }
3426
3427 Thread* THREAD = Thread::current();
3428
3429 // At this point, the Universe is initialized, but we have not executed
3430 // any byte code. Now is a good time (the only time) to dump out the
3431 // internal state of the JVM for sharing.
3432 if (DumpSharedSpaces) {
3433 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3434 ShouldNotReachHere();
3435 }
3436
3437 // Always call even when there are not JVMTI environments yet, since environments
3438 // may be attached late and JVMTI must track phases of VM execution
3439 JvmtiExport::enter_start_phase();
3440
3441 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3442 JvmtiExport::post_vm_start();
3443
3444 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3445
3446 // We need this for ClassDataSharing - the initial vm.info property is set
3447 // with the default value of CDS "sharing" which may be reset through
3448 // command line options.
3449 reset_vm_info_property(CHECK_JNI_ERR);
3450
3451 quicken_jni_functions();
3452
3453 // Must be run after init_ft which initializes ft_enabled
3454 if (TRACE_INITIALIZE() != JNI_OK) {
3455 vm_exit_during_initialization("Failed to initialize tracing backend");
3456 }
3457
3458 // Set flag that basic initialization has completed. Used by exceptions and various
3459 // debug stuff, that does not work until all basic classes have been initialized.
3460 set_init_completed();
3461
3462 Metaspace::post_initialize();
3463
3464 HOTSPOT_VM_INIT_END();
3465
3466 // record VM initialization completion time
3467 #if INCLUDE_MANAGEMENT
3468 Management::record_vm_init_completed();
3469 #endif // INCLUDE_MANAGEMENT
3470
3471 // Compute system loader. Note that this has to occur after set_init_completed, since
3472 // valid exceptions may be thrown in the process.
3473 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3474 // set_init_completed has just been called, causing exceptions not to be shortcut
3475 // anymore. We call vm_exit_during_initialization directly instead.
3476 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3477
3478 #if INCLUDE_ALL_GCS
3479 // Support for ConcurrentMarkSweep. This should be cleaned up
3480 // and better encapsulated. The ugly nested if test would go away
3481 // once things are properly refactored. XXX YSR
3482 if (UseConcMarkSweepGC || UseG1GC) {
3483 if (UseConcMarkSweepGC) {
3484 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3485 } else {
3486 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3487 }
3488 }
3489 #endif // INCLUDE_ALL_GCS
3490
3491 // Always call even when there are not JVMTI environments yet, since environments
3492 // may be attached late and JVMTI must track phases of VM execution
3493 JvmtiExport::enter_live_phase();
3494
3495 // Signal Dispatcher needs to be started before VMInit event is posted
3496 os::signal_init();
3497
3498 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3499 if (!DisableAttachMechanism) {
3500 AttachListener::vm_start();
3501 if (StartAttachListener || AttachListener::init_at_startup()) {
3502 AttachListener::init();
3503 }
3504 }
3505
3506 // Launch -Xrun agents
3507 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3508 // back-end can launch with -Xdebug -Xrunjdwp.
3509 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3510 create_vm_init_libraries();
3511 }
3512
3513 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3514 JvmtiExport::post_vm_initialized();
3515
3516 if (TRACE_START() != JNI_OK) {
3517 vm_exit_during_initialization("Failed to start tracing backend.");
3518 }
3519
3520 if (CleanChunkPoolAsync) {
3521 Chunk::start_chunk_pool_cleaner_task();
3522 }
3523
3524 // initialize compiler(s)
3525 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3526 CompileBroker::compilation_init();
3527 #endif
3528
3529 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3530 // It is done after compilers are initialized, because otherwise compilations of
3531 // signature polymorphic MH intrinsics can be missed
3532 // (see SystemDictionary::find_method_handle_intrinsic).
3533 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3534
3535 #if INCLUDE_MANAGEMENT
3536 Management::initialize(THREAD);
3537
3538 if (HAS_PENDING_EXCEPTION) {
3539 // management agent fails to start possibly due to
3540 // configuration problem and is responsible for printing
3541 // stack trace if appropriate. Simply exit VM.
3542 vm_exit(1);
3543 }
3544 #endif // INCLUDE_MANAGEMENT
3545
3546 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3547 if (MemProfiling) MemProfiler::engage();
3548 StatSampler::engage();
3549 if (CheckJNICalls) JniPeriodicChecker::engage();
3550
3551 BiasedLocking::init();
3552
3553 #if INCLUDE_RTM_OPT
3554 RTMLockingCounters::init();
3555 #endif
3556
3557 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3558 call_postVMInitHook(THREAD);
3559 // The Java side of PostVMInitHook.run must deal with all
3560 // exceptions and provide means of diagnosis.
3561 if (HAS_PENDING_EXCEPTION) {
3562 CLEAR_PENDING_EXCEPTION;
3563 }
3564 }
3565
3566 {
3567 MutexLocker ml(PeriodicTask_lock);
3568 // Make sure the WatcherThread can be started by WatcherThread::start()
3569 // or by dynamic enrollment.
3570 WatcherThread::make_startable();
3571 // Start up the WatcherThread if there are any periodic tasks
3572 // NOTE: All PeriodicTasks should be registered by now. If they
3573 // aren't, late joiners might appear to start slowly (we might
3574 // take a while to process their first tick).
3575 if (PeriodicTask::num_tasks() > 0) {
3576 WatcherThread::start();
3577 }
3578 }
3579
3580 create_vm_timer.end();
3581 #ifdef ASSERT
3582 _vm_complete = true;
3583 #endif
3584 return JNI_OK;
3585 }
3586
3587 // type for the Agent_OnLoad and JVM_OnLoad entry points
3588 extern "C" {
3589 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3590 }
3591 // Find a command line agent library and return its entry point for
3592 // -agentlib: -agentpath: -Xrun
3593 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3594 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3595 const char *on_load_symbols[],
3596 size_t num_symbol_entries) {
3597 OnLoadEntry_t on_load_entry = NULL;
3598 void *library = NULL;
3599
3600 if (!agent->valid()) {
3601 char buffer[JVM_MAXPATHLEN];
3602 char ebuf[1024] = "";
3603 const char *name = agent->name();
3604 const char *msg = "Could not find agent library ";
3605
3606 // First check to see if agent is statically linked into executable
3607 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3608 library = agent->os_lib();
3609 } else if (agent->is_absolute_path()) {
3610 library = os::dll_load(name, ebuf, sizeof ebuf);
3611 if (library == NULL) {
3612 const char *sub_msg = " in absolute path, with error: ";
3613 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3614 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3615 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3616 // If we can't find the agent, exit.
3617 vm_exit_during_initialization(buf, NULL);
3618 FREE_C_HEAP_ARRAY(char, buf);
3619 }
3620 } else {
3621 // Try to load the agent from the standard dll directory
3622 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3623 name)) {
3624 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3625 }
3626 if (library == NULL) { // Try the local directory
3627 char ns[1] = {0};
3628 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3629 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3630 }
3631 if (library == NULL) {
3632 const char *sub_msg = " on the library path, with error: ";
3633 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3634 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3635 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3636 // If we can't find the agent, exit.
3637 vm_exit_during_initialization(buf, NULL);
3638 FREE_C_HEAP_ARRAY(char, buf);
3639 }
3640 }
3641 }
3642 agent->set_os_lib(library);
3643 agent->set_valid();
3644 }
3645
3646 // Find the OnLoad function.
3647 on_load_entry =
3648 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3649 false,
3650 on_load_symbols,
3651 num_symbol_entries));
3652 return on_load_entry;
3653 }
3654
3655 // Find the JVM_OnLoad entry point
3656 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3657 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3658 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3659 }
3660
3661 // Find the Agent_OnLoad entry point
3662 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3663 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3664 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3665 }
3666
3667 // For backwards compatibility with -Xrun
3668 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3669 // treated like -agentpath:
3670 // Must be called before agent libraries are created
3671 void Threads::convert_vm_init_libraries_to_agents() {
3672 AgentLibrary* agent;
3673 AgentLibrary* next;
3674
3675 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3676 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3677 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3678
3679 // If there is an JVM_OnLoad function it will get called later,
3680 // otherwise see if there is an Agent_OnLoad
3681 if (on_load_entry == NULL) {
3682 on_load_entry = lookup_agent_on_load(agent);
3683 if (on_load_entry != NULL) {
3684 // switch it to the agent list -- so that Agent_OnLoad will be called,
3685 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3686 Arguments::convert_library_to_agent(agent);
3687 } else {
3688 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3689 }
3690 }
3691 }
3692 }
3693
3694 // Create agents for -agentlib: -agentpath: and converted -Xrun
3695 // Invokes Agent_OnLoad
3696 // Called very early -- before JavaThreads exist
3697 void Threads::create_vm_init_agents() {
3698 extern struct JavaVM_ main_vm;
3699 AgentLibrary* agent;
3700
3701 JvmtiExport::enter_onload_phase();
3702
3703 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3704 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3705
3706 if (on_load_entry != NULL) {
3707 // Invoke the Agent_OnLoad function
3708 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3709 if (err != JNI_OK) {
3710 vm_exit_during_initialization("agent library failed to init", agent->name());
3711 }
3712 } else {
3713 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3714 }
3715 }
3716 JvmtiExport::enter_primordial_phase();
3717 }
3718
3719 extern "C" {
3720 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3721 }
3722
3723 void Threads::shutdown_vm_agents() {
3724 // Send any Agent_OnUnload notifications
3725 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3726 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3727 extern struct JavaVM_ main_vm;
3728 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3729
3730 // Find the Agent_OnUnload function.
3731 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3732 os::find_agent_function(agent,
3733 false,
3734 on_unload_symbols,
3735 num_symbol_entries));
3736
3737 // Invoke the Agent_OnUnload function
3738 if (unload_entry != NULL) {
3739 JavaThread* thread = JavaThread::current();
3740 ThreadToNativeFromVM ttn(thread);
3741 HandleMark hm(thread);
3742 (*unload_entry)(&main_vm);
3743 }
3744 }
3745 }
3746
3747 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3748 // Invokes JVM_OnLoad
3749 void Threads::create_vm_init_libraries() {
3750 extern struct JavaVM_ main_vm;
3751 AgentLibrary* agent;
3752
3753 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3754 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3755
3756 if (on_load_entry != NULL) {
3757 // Invoke the JVM_OnLoad function
3758 JavaThread* thread = JavaThread::current();
3759 ThreadToNativeFromVM ttn(thread);
3760 HandleMark hm(thread);
3761 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3762 if (err != JNI_OK) {
3763 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3764 }
3765 } else {
3766 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3767 }
3768 }
3769 }
3770
3771 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3772 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3773
3774 JavaThread* java_thread = NULL;
3775 // Sequential search for now. Need to do better optimization later.
3776 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3777 oop tobj = thread->threadObj();
3778 if (!thread->is_exiting() &&
3779 tobj != NULL &&
3780 java_tid == java_lang_Thread::thread_id(tobj)) {
3781 java_thread = thread;
3782 break;
3783 }
3784 }
3785 return java_thread;
3786 }
3787
3788
3789 // Last thread running calls java.lang.Shutdown.shutdown()
3790 void JavaThread::invoke_shutdown_hooks() {
3791 HandleMark hm(this);
3792
3793 // We could get here with a pending exception, if so clear it now.
3794 if (this->has_pending_exception()) {
3795 this->clear_pending_exception();
3796 }
3797
3798 EXCEPTION_MARK;
3799 Klass* k =
3800 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3801 THREAD);
3802 if (k != NULL) {
3803 // SystemDictionary::resolve_or_null will return null if there was
3804 // an exception. If we cannot load the Shutdown class, just don't
3805 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3806 // and finalizers (if runFinalizersOnExit is set) won't be run.
3807 // Note that if a shutdown hook was registered or runFinalizersOnExit
3808 // was called, the Shutdown class would have already been loaded
3809 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3810 instanceKlassHandle shutdown_klass (THREAD, k);
3811 JavaValue result(T_VOID);
3812 JavaCalls::call_static(&result,
3813 shutdown_klass,
3814 vmSymbols::shutdown_method_name(),
3815 vmSymbols::void_method_signature(),
3816 THREAD);
3817 }
3818 CLEAR_PENDING_EXCEPTION;
3819 }
3820
3821 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3822 // the program falls off the end of main(). Another VM exit path is through
3823 // vm_exit() when the program calls System.exit() to return a value or when
3824 // there is a serious error in VM. The two shutdown paths are not exactly
3825 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3826 // and VM_Exit op at VM level.
3827 //
3828 // Shutdown sequence:
3829 // + Shutdown native memory tracking if it is on
3830 // + Wait until we are the last non-daemon thread to execute
3831 // <-- every thing is still working at this moment -->
3832 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3833 // shutdown hooks, run finalizers if finalization-on-exit
3834 // + Call before_exit(), prepare for VM exit
3835 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3836 // currently the only user of this mechanism is File.deleteOnExit())
3837 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3838 // post thread end and vm death events to JVMTI,
3839 // stop signal thread
3840 // + Call JavaThread::exit(), it will:
3841 // > release JNI handle blocks, remove stack guard pages
3842 // > remove this thread from Threads list
3843 // <-- no more Java code from this thread after this point -->
3844 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3845 // the compiler threads at safepoint
3846 // <-- do not use anything that could get blocked by Safepoint -->
3847 // + Disable tracing at JNI/JVM barriers
3848 // + Set _vm_exited flag for threads that are still running native code
3849 // + Delete this thread
3850 // + Call exit_globals()
3851 // > deletes tty
3852 // > deletes PerfMemory resources
3853 // + Return to caller
3854
3855 bool Threads::destroy_vm() {
3856 JavaThread* thread = JavaThread::current();
3857
3858 #ifdef ASSERT
3859 _vm_complete = false;
3860 #endif
3861 // Wait until we are the last non-daemon thread to execute
3862 { MutexLocker nu(Threads_lock);
3863 while (Threads::number_of_non_daemon_threads() > 1)
3864 // This wait should make safepoint checks, wait without a timeout,
3865 // and wait as a suspend-equivalent condition.
3866 //
3867 // Note: If the FlatProfiler is running and this thread is waiting
3868 // for another non-daemon thread to finish, then the FlatProfiler
3869 // is waiting for the external suspend request on this thread to
3870 // complete. wait_for_ext_suspend_completion() will eventually
3871 // timeout, but that takes time. Making this wait a suspend-
3872 // equivalent condition solves that timeout problem.
3873 //
3874 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3875 Mutex::_as_suspend_equivalent_flag);
3876 }
3877
3878 // Hang forever on exit if we are reporting an error.
3879 if (ShowMessageBoxOnError && is_error_reported()) {
3880 os::infinite_sleep();
3881 }
3882 os::wait_for_keypress_at_exit();
3883
3884 // run Java level shutdown hooks
3885 thread->invoke_shutdown_hooks();
3886
3887 before_exit(thread);
3888
3889 thread->exit(true);
3890
3891 // Stop VM thread.
3892 {
3893 // 4945125 The vm thread comes to a safepoint during exit.
3894 // GC vm_operations can get caught at the safepoint, and the
3895 // heap is unparseable if they are caught. Grab the Heap_lock
3896 // to prevent this. The GC vm_operations will not be able to
3897 // queue until after the vm thread is dead. After this point,
3898 // we'll never emerge out of the safepoint before the VM exits.
3899
3900 MutexLocker ml(Heap_lock);
3901
3902 VMThread::wait_for_vm_thread_exit();
3903 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3904 VMThread::destroy();
3905 }
3906
3907 // clean up ideal graph printers
3908 #if defined(COMPILER2) && !defined(PRODUCT)
3909 IdealGraphPrinter::clean_up();
3910 #endif
3911
3912 // Now, all Java threads are gone except daemon threads. Daemon threads
3913 // running Java code or in VM are stopped by the Safepoint. However,
3914 // daemon threads executing native code are still running. But they
3915 // will be stopped at native=>Java/VM barriers. Note that we can't
3916 // simply kill or suspend them, as it is inherently deadlock-prone.
3917
3918 #ifndef PRODUCT
3919 // disable function tracing at JNI/JVM barriers
3920 TraceJNICalls = false;
3921 TraceJVMCalls = false;
3922 TraceRuntimeCalls = false;
3923 #endif
3924
3925 VM_Exit::set_vm_exited();
3926
3927 notify_vm_shutdown();
3928
3929 delete thread;
3930
3931 // exit_globals() will delete tty
3932 exit_globals();
3933
3934 return true;
3935 }
3936
3937
3938 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3939 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3940 return is_supported_jni_version(version);
3941 }
3942
3943
3944 jboolean Threads::is_supported_jni_version(jint version) {
3945 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3946 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3947 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3948 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3949 return JNI_FALSE;
3950 }
3951
3952
3953 void Threads::add(JavaThread* p, bool force_daemon) {
3954 // The threads lock must be owned at this point
3955 assert_locked_or_safepoint(Threads_lock);
3956
3957 // See the comment for this method in thread.hpp for its purpose and
3958 // why it is called here.
3959 p->initialize_queues();
3960 p->set_next(_thread_list);
3961 _thread_list = p;
3962 _number_of_threads++;
3963 oop threadObj = p->threadObj();
3964 bool daemon = true;
3965 // Bootstrapping problem: threadObj can be null for initial
3966 // JavaThread (or for threads attached via JNI)
3967 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3968 _number_of_non_daemon_threads++;
3969 daemon = false;
3970 }
3971
3972 ThreadService::add_thread(p, daemon);
3973
3974 // Possible GC point.
3975 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
3976 }
3977
3978 void Threads::remove(JavaThread* p) {
3979 // Extra scope needed for Thread_lock, so we can check
3980 // that we do not remove thread without safepoint code notice
3981 { MutexLocker ml(Threads_lock);
3982
3983 assert(includes(p), "p must be present");
3984
3985 JavaThread* current = _thread_list;
3986 JavaThread* prev = NULL;
3987
3988 while (current != p) {
3989 prev = current;
3990 current = current->next();
3991 }
3992
3993 if (prev) {
3994 prev->set_next(current->next());
3995 } else {
3996 _thread_list = p->next();
3997 }
3998 _number_of_threads--;
3999 oop threadObj = p->threadObj();
4000 bool daemon = true;
4001 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4002 _number_of_non_daemon_threads--;
4003 daemon = false;
4004
4005 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4006 // on destroy_vm will wake up.
4007 if (number_of_non_daemon_threads() == 1) {
4008 Threads_lock->notify_all();
4009 }
4010 }
4011 ThreadService::remove_thread(p, daemon);
4012
4013 // Make sure that safepoint code disregard this thread. This is needed since
4014 // the thread might mess around with locks after this point. This can cause it
4015 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4016 // of this thread since it is removed from the queue.
4017 p->set_terminated_value();
4018 } // unlock Threads_lock
4019
4020 // Since Events::log uses a lock, we grab it outside the Threads_lock
4021 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4022 }
4023
4024 // Threads_lock must be held when this is called (or must be called during a safepoint)
4025 bool Threads::includes(JavaThread* p) {
4026 assert(Threads_lock->is_locked(), "sanity check");
4027 ALL_JAVA_THREADS(q) {
4028 if (q == p) {
4029 return true;
4030 }
4031 }
4032 return false;
4033 }
4034
4035 // Operations on the Threads list for GC. These are not explicitly locked,
4036 // but the garbage collector must provide a safe context for them to run.
4037 // In particular, these things should never be called when the Threads_lock
4038 // is held by some other thread. (Note: the Safepoint abstraction also
4039 // uses the Threads_lock to guarantee this property. It also makes sure that
4040 // all threads gets blocked when exiting or starting).
4041
4042 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4043 ALL_JAVA_THREADS(p) {
4044 p->oops_do(f, cld_f, cf);
4045 }
4046 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4047 }
4048
4049 void Threads::change_thread_claim_parity() {
4050 // Set the new claim parity.
4051 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4052 "Not in range.");
4053 _thread_claim_parity++;
4054 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4055 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4056 "Not in range.");
4057 }
4058
4059 #ifndef PRODUCT
4060 void Threads::assert_all_threads_claimed() {
4061 ALL_JAVA_THREADS(p) {
4062 const int thread_parity = p->oops_do_parity();
4063 assert((thread_parity == _thread_claim_parity),
4064 err_msg("Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity));
4065 }
4066 }
4067 #endif // PRODUCT
4068
4069 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4070 // Introduce a mechanism allowing parallel threads to claim threads as
4071 // root groups. Overhead should be small enough to use all the time,
4072 // even in sequential code.
4073 SharedHeap* sh = SharedHeap::heap();
4074 // Cannot yet substitute active_workers for n_par_threads
4075 // because of G1CollectedHeap::verify() use of
4076 // SharedHeap::process_roots(). n_par_threads == 0 will
4077 // turn off parallelism in process_roots while active_workers
4078 // is being used for parallelism elsewhere.
4079 bool is_par = sh->n_par_threads() > 0;
4080 assert(!is_par ||
4081 (SharedHeap::heap()->n_par_threads() ==
4082 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4083 int cp = Threads::thread_claim_parity();
4084 ALL_JAVA_THREADS(p) {
4085 if (p->claim_oops_do(is_par, cp)) {
4086 p->oops_do(f, cld_f, cf);
4087 }
4088 }
4089 VMThread* vmt = VMThread::vm_thread();
4090 if (vmt->claim_oops_do(is_par, cp)) {
4091 vmt->oops_do(f, cld_f, cf);
4092 }
4093 }
4094
4095 #if INCLUDE_ALL_GCS
4096 // Used by ParallelScavenge
4097 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4098 ALL_JAVA_THREADS(p) {
4099 q->enqueue(new ThreadRootsTask(p));
4100 }
4101 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4102 }
4103
4104 // Used by Parallel Old
4105 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4106 ALL_JAVA_THREADS(p) {
4107 q->enqueue(new ThreadRootsMarkingTask(p));
4108 }
4109 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4110 }
4111 #endif // INCLUDE_ALL_GCS
4112
4113 void Threads::nmethods_do(CodeBlobClosure* cf) {
4114 ALL_JAVA_THREADS(p) {
4115 p->nmethods_do(cf);
4116 }
4117 VMThread::vm_thread()->nmethods_do(cf);
4118 }
4119
4120 void Threads::metadata_do(void f(Metadata*)) {
4121 ALL_JAVA_THREADS(p) {
4122 p->metadata_do(f);
4123 }
4124 }
4125
4126 class ThreadHandlesClosure : public ThreadClosure {
4127 void (*_f)(Metadata*);
4128 public:
4129 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4130 virtual void do_thread(Thread* thread) {
4131 thread->metadata_handles_do(_f);
4132 }
4133 };
4134
4135 void Threads::metadata_handles_do(void f(Metadata*)) {
4136 // Only walk the Handles in Thread.
4137 ThreadHandlesClosure handles_closure(f);
4138 threads_do(&handles_closure);
4139 }
4140
4141 void Threads::deoptimized_wrt_marked_nmethods() {
4142 ALL_JAVA_THREADS(p) {
4143 p->deoptimized_wrt_marked_nmethods();
4144 }
4145 }
4146
4147
4148 // Get count Java threads that are waiting to enter the specified monitor.
4149 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4150 address monitor,
4151 bool doLock) {
4152 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4153 "must grab Threads_lock or be at safepoint");
4154 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4155
4156 int i = 0;
4157 {
4158 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4159 ALL_JAVA_THREADS(p) {
4160 if (p->is_Compiler_thread()) continue;
4161
4162 address pending = (address)p->current_pending_monitor();
4163 if (pending == monitor) { // found a match
4164 if (i < count) result->append(p); // save the first count matches
4165 i++;
4166 }
4167 }
4168 }
4169 return result;
4170 }
4171
4172
4173 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4174 bool doLock) {
4175 assert(doLock ||
4176 Threads_lock->owned_by_self() ||
4177 SafepointSynchronize::is_at_safepoint(),
4178 "must grab Threads_lock or be at safepoint");
4179
4180 // NULL owner means not locked so we can skip the search
4181 if (owner == NULL) return NULL;
4182
4183 {
4184 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4185 ALL_JAVA_THREADS(p) {
4186 // first, see if owner is the address of a Java thread
4187 if (owner == (address)p) return p;
4188 }
4189 }
4190 // Cannot assert on lack of success here since this function may be
4191 // used by code that is trying to report useful problem information
4192 // like deadlock detection.
4193 if (UseHeavyMonitors) return NULL;
4194
4195 // If we didn't find a matching Java thread and we didn't force use of
4196 // heavyweight monitors, then the owner is the stack address of the
4197 // Lock Word in the owning Java thread's stack.
4198 //
4199 JavaThread* the_owner = NULL;
4200 {
4201 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4202 ALL_JAVA_THREADS(q) {
4203 if (q->is_lock_owned(owner)) {
4204 the_owner = q;
4205 break;
4206 }
4207 }
4208 }
4209 // cannot assert on lack of success here; see above comment
4210 return the_owner;
4211 }
4212
4213 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4214 void Threads::print_on(outputStream* st, bool print_stacks,
4215 bool internal_format, bool print_concurrent_locks) {
4216 char buf[32];
4217 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4218
4219 st->print_cr("Full thread dump %s (%s %s):",
4220 Abstract_VM_Version::vm_name(),
4221 Abstract_VM_Version::vm_release(),
4222 Abstract_VM_Version::vm_info_string());
4223 st->cr();
4224
4225 #if INCLUDE_ALL_GCS
4226 // Dump concurrent locks
4227 ConcurrentLocksDump concurrent_locks;
4228 if (print_concurrent_locks) {
4229 concurrent_locks.dump_at_safepoint();
4230 }
4231 #endif // INCLUDE_ALL_GCS
4232
4233 ALL_JAVA_THREADS(p) {
4234 ResourceMark rm;
4235 p->print_on(st);
4236 if (print_stacks) {
4237 if (internal_format) {
4238 p->trace_stack();
4239 } else {
4240 p->print_stack_on(st);
4241 }
4242 }
4243 st->cr();
4244 #if INCLUDE_ALL_GCS
4245 if (print_concurrent_locks) {
4246 concurrent_locks.print_locks_on(p, st);
4247 }
4248 #endif // INCLUDE_ALL_GCS
4249 }
4250
4251 VMThread::vm_thread()->print_on(st);
4252 st->cr();
4253 Universe::heap()->print_gc_threads_on(st);
4254 WatcherThread* wt = WatcherThread::watcher_thread();
4255 if (wt != NULL) {
4256 wt->print_on(st);
4257 st->cr();
4258 }
4259 CompileBroker::print_compiler_threads_on(st);
4260 st->flush();
4261 }
4262
4263 // Threads::print_on_error() is called by fatal error handler. It's possible
4264 // that VM is not at safepoint and/or current thread is inside signal handler.
4265 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4266 // memory (even in resource area), it might deadlock the error handler.
4267 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4268 int buflen) {
4269 bool found_current = false;
4270 st->print_cr("Java Threads: ( => current thread )");
4271 ALL_JAVA_THREADS(thread) {
4272 bool is_current = (current == thread);
4273 found_current = found_current || is_current;
4274
4275 st->print("%s", is_current ? "=>" : " ");
4276
4277 st->print(PTR_FORMAT, thread);
4278 st->print(" ");
4279 thread->print_on_error(st, buf, buflen);
4280 st->cr();
4281 }
4282 st->cr();
4283
4284 st->print_cr("Other Threads:");
4285 if (VMThread::vm_thread()) {
4286 bool is_current = (current == VMThread::vm_thread());
4287 found_current = found_current || is_current;
4288 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4289
4290 st->print(PTR_FORMAT, VMThread::vm_thread());
4291 st->print(" ");
4292 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4293 st->cr();
4294 }
4295 WatcherThread* wt = WatcherThread::watcher_thread();
4296 if (wt != NULL) {
4297 bool is_current = (current == wt);
4298 found_current = found_current || is_current;
4299 st->print("%s", is_current ? "=>" : " ");
4300
4301 st->print(PTR_FORMAT, wt);
4302 st->print(" ");
4303 wt->print_on_error(st, buf, buflen);
4304 st->cr();
4305 }
4306 if (!found_current) {
4307 st->cr();
4308 st->print("=>" PTR_FORMAT " (exited) ", current);
4309 current->print_on_error(st, buf, buflen);
4310 st->cr();
4311 }
4312 }
4313
4314 // Internal SpinLock and Mutex
4315 // Based on ParkEvent
4316
4317 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4318 //
4319 // We employ SpinLocks _only for low-contention, fixed-length
4320 // short-duration critical sections where we're concerned
4321 // about native mutex_t or HotSpot Mutex:: latency.
4322 // The mux construct provides a spin-then-block mutual exclusion
4323 // mechanism.
4324 //
4325 // Testing has shown that contention on the ListLock guarding gFreeList
4326 // is common. If we implement ListLock as a simple SpinLock it's common
4327 // for the JVM to devolve to yielding with little progress. This is true
4328 // despite the fact that the critical sections protected by ListLock are
4329 // extremely short.
4330 //
4331 // TODO-FIXME: ListLock should be of type SpinLock.
4332 // We should make this a 1st-class type, integrated into the lock
4333 // hierarchy as leaf-locks. Critically, the SpinLock structure
4334 // should have sufficient padding to avoid false-sharing and excessive
4335 // cache-coherency traffic.
4336
4337
4338 typedef volatile int SpinLockT;
4339
4340 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4341 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4342 return; // normal fast-path return
4343 }
4344
4345 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4346 TEVENT(SpinAcquire - ctx);
4347 int ctr = 0;
4348 int Yields = 0;
4349 for (;;) {
4350 while (*adr != 0) {
4351 ++ctr;
4352 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4353 if (Yields > 5) {
4354 os::naked_short_sleep(1);
4355 } else {
4356 os::naked_yield();
4357 ++Yields;
4358 }
4359 } else {
4360 SpinPause();
4361 }
4362 }
4363 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4364 }
4365 }
4366
4367 void Thread::SpinRelease(volatile int * adr) {
4368 assert(*adr != 0, "invariant");
4369 OrderAccess::fence(); // guarantee at least release consistency.
4370 // Roach-motel semantics.
4371 // It's safe if subsequent LDs and STs float "up" into the critical section,
4372 // but prior LDs and STs within the critical section can't be allowed
4373 // to reorder or float past the ST that releases the lock.
4374 // Loads and stores in the critical section - which appear in program
4375 // order before the store that releases the lock - must also appear
4376 // before the store that releases the lock in memory visibility order.
4377 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4378 // the ST of 0 into the lock-word which releases the lock, so fence
4379 // more than covers this on all platforms.
4380 *adr = 0;
4381 }
4382
4383 // muxAcquire and muxRelease:
4384 //
4385 // * muxAcquire and muxRelease support a single-word lock-word construct.
4386 // The LSB of the word is set IFF the lock is held.
4387 // The remainder of the word points to the head of a singly-linked list
4388 // of threads blocked on the lock.
4389 //
4390 // * The current implementation of muxAcquire-muxRelease uses its own
4391 // dedicated Thread._MuxEvent instance. If we're interested in
4392 // minimizing the peak number of extant ParkEvent instances then
4393 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4394 // as certain invariants were satisfied. Specifically, care would need
4395 // to be taken with regards to consuming unpark() "permits".
4396 // A safe rule of thumb is that a thread would never call muxAcquire()
4397 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4398 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4399 // consume an unpark() permit intended for monitorenter, for instance.
4400 // One way around this would be to widen the restricted-range semaphore
4401 // implemented in park(). Another alternative would be to provide
4402 // multiple instances of the PlatformEvent() for each thread. One
4403 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4404 //
4405 // * Usage:
4406 // -- Only as leaf locks
4407 // -- for short-term locking only as muxAcquire does not perform
4408 // thread state transitions.
4409 //
4410 // Alternatives:
4411 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4412 // but with parking or spin-then-park instead of pure spinning.
4413 // * Use Taura-Oyama-Yonenzawa locks.
4414 // * It's possible to construct a 1-0 lock if we encode the lockword as
4415 // (List,LockByte). Acquire will CAS the full lockword while Release
4416 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4417 // acquiring threads use timers (ParkTimed) to detect and recover from
4418 // the stranding window. Thread/Node structures must be aligned on 256-byte
4419 // boundaries by using placement-new.
4420 // * Augment MCS with advisory back-link fields maintained with CAS().
4421 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4422 // The validity of the backlinks must be ratified before we trust the value.
4423 // If the backlinks are invalid the exiting thread must back-track through the
4424 // the forward links, which are always trustworthy.
4425 // * Add a successor indication. The LockWord is currently encoded as
4426 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4427 // to provide the usual futile-wakeup optimization.
4428 // See RTStt for details.
4429 // * Consider schedctl.sc_nopreempt to cover the critical section.
4430 //
4431
4432
4433 typedef volatile intptr_t MutexT; // Mux Lock-word
4434 enum MuxBits { LOCKBIT = 1 };
4435
4436 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4437 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4438 if (w == 0) return;
4439 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4440 return;
4441 }
4442
4443 TEVENT(muxAcquire - Contention);
4444 ParkEvent * const Self = Thread::current()->_MuxEvent;
4445 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4446 for (;;) {
4447 int its = (os::is_MP() ? 100 : 0) + 1;
4448
4449 // Optional spin phase: spin-then-park strategy
4450 while (--its >= 0) {
4451 w = *Lock;
4452 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4453 return;
4454 }
4455 }
4456
4457 Self->reset();
4458 Self->OnList = intptr_t(Lock);
4459 // The following fence() isn't _strictly necessary as the subsequent
4460 // CAS() both serializes execution and ratifies the fetched *Lock value.
4461 OrderAccess::fence();
4462 for (;;) {
4463 w = *Lock;
4464 if ((w & LOCKBIT) == 0) {
4465 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4466 Self->OnList = 0; // hygiene - allows stronger asserts
4467 return;
4468 }
4469 continue; // Interference -- *Lock changed -- Just retry
4470 }
4471 assert(w & LOCKBIT, "invariant");
4472 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4473 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4474 }
4475
4476 while (Self->OnList != 0) {
4477 Self->park();
4478 }
4479 }
4480 }
4481
4482 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4483 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4484 if (w == 0) return;
4485 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4486 return;
4487 }
4488
4489 TEVENT(muxAcquire - Contention);
4490 ParkEvent * ReleaseAfter = NULL;
4491 if (ev == NULL) {
4492 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4493 }
4494 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4495 for (;;) {
4496 guarantee(ev->OnList == 0, "invariant");
4497 int its = (os::is_MP() ? 100 : 0) + 1;
4498
4499 // Optional spin phase: spin-then-park strategy
4500 while (--its >= 0) {
4501 w = *Lock;
4502 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4503 if (ReleaseAfter != NULL) {
4504 ParkEvent::Release(ReleaseAfter);
4505 }
4506 return;
4507 }
4508 }
4509
4510 ev->reset();
4511 ev->OnList = intptr_t(Lock);
4512 // The following fence() isn't _strictly necessary as the subsequent
4513 // CAS() both serializes execution and ratifies the fetched *Lock value.
4514 OrderAccess::fence();
4515 for (;;) {
4516 w = *Lock;
4517 if ((w & LOCKBIT) == 0) {
4518 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4519 ev->OnList = 0;
4520 // We call ::Release while holding the outer lock, thus
4521 // artificially lengthening the critical section.
4522 // Consider deferring the ::Release() until the subsequent unlock(),
4523 // after we've dropped the outer lock.
4524 if (ReleaseAfter != NULL) {
4525 ParkEvent::Release(ReleaseAfter);
4526 }
4527 return;
4528 }
4529 continue; // Interference -- *Lock changed -- Just retry
4530 }
4531 assert(w & LOCKBIT, "invariant");
4532 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4533 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4534 }
4535
4536 while (ev->OnList != 0) {
4537 ev->park();
4538 }
4539 }
4540 }
4541
4542 // Release() must extract a successor from the list and then wake that thread.
4543 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4544 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4545 // Release() would :
4546 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4547 // (B) Extract a successor from the private list "in-hand"
4548 // (C) attempt to CAS() the residual back into *Lock over null.
4549 // If there were any newly arrived threads and the CAS() would fail.
4550 // In that case Release() would detach the RATs, re-merge the list in-hand
4551 // with the RATs and repeat as needed. Alternately, Release() might
4552 // detach and extract a successor, but then pass the residual list to the wakee.
4553 // The wakee would be responsible for reattaching and remerging before it
4554 // competed for the lock.
4555 //
4556 // Both "pop" and DMR are immune from ABA corruption -- there can be
4557 // multiple concurrent pushers, but only one popper or detacher.
4558 // This implementation pops from the head of the list. This is unfair,
4559 // but tends to provide excellent throughput as hot threads remain hot.
4560 // (We wake recently run threads first).
4561 //
4562 // All paths through muxRelease() will execute a CAS.
4563 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4564 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4565 // executed within the critical section are complete and globally visible before the
4566 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4567 void Thread::muxRelease(volatile intptr_t * Lock) {
4568 for (;;) {
4569 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4570 assert(w & LOCKBIT, "invariant");
4571 if (w == LOCKBIT) return;
4572 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4573 assert(List != NULL, "invariant");
4574 assert(List->OnList == intptr_t(Lock), "invariant");
4575 ParkEvent * const nxt = List->ListNext;
4576 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4577
4578 // The following CAS() releases the lock and pops the head element.
4579 // The CAS() also ratifies the previously fetched lock-word value.
4580 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4581 continue;
4582 }
4583 List->OnList = 0;
4584 OrderAccess::fence();
4585 List->unpark();
4586 return;
4587 }
4588 }
4589
4590
4591 void Threads::verify() {
4592 ALL_JAVA_THREADS(p) {
4593 p->verify();
4594 }
4595 VMThread* thread = VMThread::vm_thread();
4596 if (thread != NULL) thread->verify();
4597 }