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/codeCacheExtensions.hpp"
32 #include "code/scopeDesc.hpp"
33 #include "compiler/compileBroker.hpp"
34 #include "gc/shared/gcLocker.inline.hpp"
35 #include "gc/shared/workgroup.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "interpreter/linkResolver.hpp"
38 #include "interpreter/oopMapCache.hpp"
39 #include "jvmtifiles/jvmtiEnv.hpp"
40 #include "memory/metaspaceShared.hpp"
41 #include "memory/oopFactory.hpp"
42 #include "memory/universe.inline.hpp"
43 #include "oops/instanceKlass.hpp"
44 #include "oops/objArrayOop.hpp"
45 #include "oops/oop.inline.hpp"
46 #include "oops/symbol.hpp"
47 #include "oops/verifyOopClosure.hpp"
48 #include "prims/jvm_misc.hpp"
49 #include "prims/jvmtiExport.hpp"
50 #include "prims/jvmtiThreadState.hpp"
51 #include "prims/privilegedStack.hpp"
52 #include "runtime/arguments.hpp"
53 #include "runtime/atomic.inline.hpp"
54 #include "runtime/biasedLocking.hpp"
55 #include "runtime/deoptimization.hpp"
56 #include "runtime/fprofiler.hpp"
57 #include "runtime/frame.inline.hpp"
58 #include "runtime/globals.hpp"
59 #include "runtime/init.hpp"
60 #include "runtime/interfaceSupport.hpp"
61 #include "runtime/java.hpp"
62 #include "runtime/javaCalls.hpp"
63 #include "runtime/jniPeriodicChecker.hpp"
64 #include "runtime/memprofiler.hpp"
65 #include "runtime/mutexLocker.hpp"
66 #include "runtime/objectMonitor.hpp"
67 #include "runtime/orderAccess.inline.hpp"
68 #include "runtime/osThread.hpp"
69 #include "runtime/safepoint.hpp"
70 #include "runtime/sharedRuntime.hpp"
71 #include "runtime/statSampler.hpp"
72 #include "runtime/stubRoutines.hpp"
73 #include "runtime/sweeper.hpp"
74 #include "runtime/task.hpp"
75 #include "runtime/thread.inline.hpp"
76 #include "runtime/threadCritical.hpp"
77 #include "runtime/threadLocalStorage.hpp"
78 #include "runtime/vframe.hpp"
79 #include "runtime/vframeArray.hpp"
80 #include "runtime/vframe_hp.hpp"
81 #include "runtime/vmThread.hpp"
82 #include "runtime/vm_operations.hpp"
83 #include "runtime/vm_version.hpp"
84 #include "services/attachListener.hpp"
85 #include "services/management.hpp"
86 #include "services/memTracker.hpp"
87 #include "services/threadService.hpp"
88 #include "trace/traceMacros.hpp"
89 #include "trace/tracing.hpp"
90 #include "utilities/defaultStream.hpp"
91 #include "utilities/dtrace.hpp"
92 #include "utilities/events.hpp"
93 #include "utilities/macros.hpp"
94 #include "utilities/preserveException.hpp"
95 #if INCLUDE_ALL_GCS
96 #include "gc/cms/concurrentMarkSweepThread.hpp"
97 #include "gc/g1/concurrentMarkThread.inline.hpp"
98 #include "gc/parallel/pcTasks.hpp"
99 #endif // INCLUDE_ALL_GCS
100 #ifdef COMPILER1
101 #include "c1/c1_Compiler.hpp"
102 #endif
103 #ifdef COMPILER2
104 #include "opto/c2compiler.hpp"
105 #include "opto/idealGraphPrinter.hpp"
106 #endif
107 #if INCLUDE_RTM_OPT
108 #include "runtime/rtmLocking.hpp"
109 #endif
110
111 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
112
113 #ifdef DTRACE_ENABLED
114
115 // Only bother with this argument setup if dtrace is available
116
117 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
118 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
119
120 #define DTRACE_THREAD_PROBE(probe, javathread) \
121 { \
122 ResourceMark rm(this); \
123 int len = 0; \
124 const char* name = (javathread)->get_thread_name(); \
125 len = strlen(name); \
126 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
127 (char *) name, len, \
128 java_lang_Thread::thread_id((javathread)->threadObj()), \
129 (uintptr_t) (javathread)->osthread()->thread_id(), \
130 java_lang_Thread::is_daemon((javathread)->threadObj())); \
131 }
132
133 #else // ndef DTRACE_ENABLED
134
135 #define DTRACE_THREAD_PROBE(probe, javathread)
136
137 #endif // ndef DTRACE_ENABLED
138
139
140 // Class hierarchy
141 // - Thread
142 // - VMThread
143 // - WatcherThread
144 // - ConcurrentMarkSweepThread
145 // - JavaThread
146 // - CompilerThread
147
148 // ======= Thread ========
149 // Support for forcing alignment of thread objects for biased locking
150 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
151 if (UseBiasedLocking) {
152 const int alignment = markOopDesc::biased_lock_alignment;
153 size_t aligned_size = size + (alignment - sizeof(intptr_t));
154 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
155 : AllocateHeap(aligned_size, flags, CURRENT_PC,
156 AllocFailStrategy::RETURN_NULL);
157 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
158 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
159 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
160 "JavaThread alignment code overflowed allocated storage");
161 if (TraceBiasedLocking) {
162 if (aligned_addr != real_malloc_addr) {
163 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
164 real_malloc_addr, aligned_addr);
165 }
166 }
167 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
168 return aligned_addr;
169 } else {
170 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
171 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
172 }
173 }
174
175 void Thread::operator delete(void* p) {
176 if (UseBiasedLocking) {
177 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
178 FreeHeap(real_malloc_addr);
179 } else {
180 FreeHeap(p);
181 }
182 }
183
184
185 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
186 // JavaThread
187
188
189 Thread::Thread() {
190 // stack and get_thread
191 set_stack_base(NULL);
192 set_stack_size(0);
193 set_self_raw_id(0);
194 set_lgrp_id(-1);
195 DEBUG_ONLY(clear_suspendible_thread();)
196
197 // allocated data structures
198 set_osthread(NULL);
199 set_resource_area(new (mtThread)ResourceArea());
200 DEBUG_ONLY(_current_resource_mark = NULL;)
201 set_handle_area(new (mtThread) HandleArea(NULL));
202 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
203 set_active_handles(NULL);
204 set_free_handle_block(NULL);
205 set_last_handle_mark(NULL);
206
207 // This initial value ==> never claimed.
208 _oops_do_parity = 0;
209
210 // the handle mark links itself to last_handle_mark
211 new HandleMark(this);
212
213 // plain initialization
214 debug_only(_owned_locks = NULL;)
215 debug_only(_allow_allocation_count = 0;)
216 NOT_PRODUCT(_allow_safepoint_count = 0;)
217 NOT_PRODUCT(_skip_gcalot = false;)
218 _jvmti_env_iteration_count = 0;
219 set_allocated_bytes(0);
220 _vm_operation_started_count = 0;
221 _vm_operation_completed_count = 0;
222 _current_pending_monitor = NULL;
223 _current_pending_monitor_is_from_java = true;
224 _current_waiting_monitor = NULL;
225 _num_nested_signal = 0;
226 omFreeList = NULL;
227 omFreeCount = 0;
228 omFreeProvision = 32;
229 omInUseList = NULL;
230 omInUseCount = 0;
231
232 #ifdef ASSERT
233 _visited_for_critical_count = false;
234 #endif
235
236 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
237 Monitor::_safepoint_check_sometimes);
238 _suspend_flags = 0;
239
240 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
241 _hashStateX = os::random();
242 _hashStateY = 842502087;
243 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
244 _hashStateW = 273326509;
245
246 _OnTrap = 0;
247 _schedctl = NULL;
248 _Stalled = 0;
249 _TypeTag = 0x2BAD;
250
251 // Many of the following fields are effectively final - immutable
252 // Note that nascent threads can't use the Native Monitor-Mutex
253 // construct until the _MutexEvent is initialized ...
254 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
255 // we might instead use a stack of ParkEvents that we could provision on-demand.
256 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
257 // and ::Release()
258 _ParkEvent = ParkEvent::Allocate(this);
259 _SleepEvent = ParkEvent::Allocate(this);
260 _MutexEvent = ParkEvent::Allocate(this);
261 _MuxEvent = ParkEvent::Allocate(this);
262
263 #ifdef CHECK_UNHANDLED_OOPS
264 if (CheckUnhandledOops) {
265 _unhandled_oops = new UnhandledOops(this);
266 }
267 #endif // CHECK_UNHANDLED_OOPS
268 #ifdef ASSERT
269 if (UseBiasedLocking) {
270 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
271 assert(this == _real_malloc_address ||
272 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
273 "bug in forced alignment of thread objects");
274 }
275 #endif // ASSERT
276 }
277
278 // Non-inlined version to be used where thread.inline.hpp shouldn't be included.
279 Thread* Thread::current_noinline() {
280 return Thread::current();
281 }
282
283 void Thread::initialize_thread_local_storage() {
284 // Note: Make sure this method only calls
285 // non-blocking operations. Otherwise, it might not work
286 // with the thread-startup/safepoint interaction.
287
288 // During Java thread startup, safepoint code should allow this
289 // method to complete because it may need to allocate memory to
290 // store information for the new thread.
291
292 // initialize structure dependent on thread local storage
293 ThreadLocalStorage::set_thread(this);
294 }
295
296 void Thread::record_stack_base_and_size() {
297 set_stack_base(os::current_stack_base());
298 set_stack_size(os::current_stack_size());
299 if (is_Java_thread()) {
300 ((JavaThread*) this)->set_stack_overflow_limit();
301 }
302 // CR 7190089: on Solaris, primordial thread's stack is adjusted
303 // in initialize_thread(). Without the adjustment, stack size is
304 // incorrect if stack is set to unlimited (ulimit -s unlimited).
305 // So far, only Solaris has real implementation of initialize_thread().
306 //
307 // set up any platform-specific state.
308 os::initialize_thread(this);
309
310 #if INCLUDE_NMT
311 // record thread's native stack, stack grows downward
312 address stack_low_addr = stack_base() - stack_size();
313 MemTracker::record_thread_stack(stack_low_addr, stack_size());
314 #endif // INCLUDE_NMT
315 }
316
317
318 Thread::~Thread() {
319 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
320 ObjectSynchronizer::omFlush(this);
321
322 EVENT_THREAD_DESTRUCT(this);
323
324 // stack_base can be NULL if the thread is never started or exited before
325 // record_stack_base_and_size called. Although, we would like to ensure
326 // that all started threads do call record_stack_base_and_size(), there is
327 // not proper way to enforce that.
328 #if INCLUDE_NMT
329 if (_stack_base != NULL) {
330 address low_stack_addr = stack_base() - stack_size();
331 MemTracker::release_thread_stack(low_stack_addr, stack_size());
332 #ifdef ASSERT
333 set_stack_base(NULL);
334 #endif
335 }
336 #endif // INCLUDE_NMT
337
338 // deallocate data structures
339 delete resource_area();
340 // since the handle marks are using the handle area, we have to deallocated the root
341 // handle mark before deallocating the thread's handle area,
342 assert(last_handle_mark() != NULL, "check we have an element");
343 delete last_handle_mark();
344 assert(last_handle_mark() == NULL, "check we have reached the end");
345
346 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
347 // We NULL out the fields for good hygiene.
348 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
349 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
350 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
351 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
352
353 delete handle_area();
354 delete metadata_handles();
355
356 // osthread() can be NULL, if creation of thread failed.
357 if (osthread() != NULL) os::free_thread(osthread());
358
359 delete _SR_lock;
360
361 // clear thread local storage if the Thread is deleting itself
362 if (this == Thread::current()) {
363 ThreadLocalStorage::set_thread(NULL);
364 } else {
365 // In the case where we're not the current thread, invalidate all the
366 // caches in case some code tries to get the current thread or the
367 // thread that was destroyed, and gets stale information.
368 ThreadLocalStorage::invalidate_all();
369 }
370 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
371 }
372
373 // NOTE: dummy function for assertion purpose.
374 void Thread::run() {
375 ShouldNotReachHere();
376 }
377
378 #ifdef ASSERT
379 // Private method to check for dangling thread pointer
380 void check_for_dangling_thread_pointer(Thread *thread) {
381 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
382 "possibility of dangling Thread pointer");
383 }
384 #endif
385
386 ThreadPriority Thread::get_priority(const Thread* const thread) {
387 ThreadPriority priority;
388 // Can return an error!
389 (void)os::get_priority(thread, priority);
390 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
391 return priority;
392 }
393
394 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
395 debug_only(check_for_dangling_thread_pointer(thread);)
396 // Can return an error!
397 (void)os::set_priority(thread, priority);
398 }
399
400
401 void Thread::start(Thread* thread) {
402 // Start is different from resume in that its safety is guaranteed by context or
403 // being called from a Java method synchronized on the Thread object.
404 if (!DisableStartThread) {
405 if (thread->is_Java_thread()) {
406 // Initialize the thread state to RUNNABLE before starting this thread.
407 // Can not set it after the thread started because we do not know the
408 // exact thread state at that time. It could be in MONITOR_WAIT or
409 // in SLEEPING or some other state.
410 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
411 java_lang_Thread::RUNNABLE);
412 }
413 os::start_thread(thread);
414 }
415 }
416
417 // Enqueue a VM_Operation to do the job for us - sometime later
418 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
419 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
420 VMThread::execute(vm_stop);
421 }
422
423
424 // Check if an external suspend request has completed (or has been
425 // cancelled). Returns true if the thread is externally suspended and
426 // false otherwise.
427 //
428 // The bits parameter returns information about the code path through
429 // the routine. Useful for debugging:
430 //
431 // set in is_ext_suspend_completed():
432 // 0x00000001 - routine was entered
433 // 0x00000010 - routine return false at end
434 // 0x00000100 - thread exited (return false)
435 // 0x00000200 - suspend request cancelled (return false)
436 // 0x00000400 - thread suspended (return true)
437 // 0x00001000 - thread is in a suspend equivalent state (return true)
438 // 0x00002000 - thread is native and walkable (return true)
439 // 0x00004000 - thread is native_trans and walkable (needed retry)
440 //
441 // set in wait_for_ext_suspend_completion():
442 // 0x00010000 - routine was entered
443 // 0x00020000 - suspend request cancelled before loop (return false)
444 // 0x00040000 - thread suspended before loop (return true)
445 // 0x00080000 - suspend request cancelled in loop (return false)
446 // 0x00100000 - thread suspended in loop (return true)
447 // 0x00200000 - suspend not completed during retry loop (return false)
448
449 // Helper class for tracing suspend wait debug bits.
450 //
451 // 0x00000100 indicates that the target thread exited before it could
452 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
453 // 0x00080000 each indicate a cancelled suspend request so they don't
454 // count as wait failures either.
455 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
456
457 class TraceSuspendDebugBits : public StackObj {
458 private:
459 JavaThread * jt;
460 bool is_wait;
461 bool called_by_wait; // meaningful when !is_wait
462 uint32_t * bits;
463
464 public:
465 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
466 uint32_t *_bits) {
467 jt = _jt;
468 is_wait = _is_wait;
469 called_by_wait = _called_by_wait;
470 bits = _bits;
471 }
472
473 ~TraceSuspendDebugBits() {
474 if (!is_wait) {
475 #if 1
476 // By default, don't trace bits for is_ext_suspend_completed() calls.
477 // That trace is very chatty.
478 return;
479 #else
480 if (!called_by_wait) {
481 // If tracing for is_ext_suspend_completed() is enabled, then only
482 // trace calls to it from wait_for_ext_suspend_completion()
483 return;
484 }
485 #endif
486 }
487
488 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
489 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
490 MutexLocker ml(Threads_lock); // needed for get_thread_name()
491 ResourceMark rm;
492
493 tty->print_cr(
494 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
495 jt->get_thread_name(), *bits);
496
497 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
498 }
499 }
500 }
501 };
502 #undef DEBUG_FALSE_BITS
503
504
505 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
506 uint32_t *bits) {
507 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
508
509 bool did_trans_retry = false; // only do thread_in_native_trans retry once
510 bool do_trans_retry; // flag to force the retry
511
512 *bits |= 0x00000001;
513
514 do {
515 do_trans_retry = false;
516
517 if (is_exiting()) {
518 // Thread is in the process of exiting. This is always checked
519 // first to reduce the risk of dereferencing a freed JavaThread.
520 *bits |= 0x00000100;
521 return false;
522 }
523
524 if (!is_external_suspend()) {
525 // Suspend request is cancelled. This is always checked before
526 // is_ext_suspended() to reduce the risk of a rogue resume
527 // confusing the thread that made the suspend request.
528 *bits |= 0x00000200;
529 return false;
530 }
531
532 if (is_ext_suspended()) {
533 // thread is suspended
534 *bits |= 0x00000400;
535 return true;
536 }
537
538 // Now that we no longer do hard suspends of threads running
539 // native code, the target thread can be changing thread state
540 // while we are in this routine:
541 //
542 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
543 //
544 // We save a copy of the thread state as observed at this moment
545 // and make our decision about suspend completeness based on the
546 // copy. This closes the race where the thread state is seen as
547 // _thread_in_native_trans in the if-thread_blocked check, but is
548 // seen as _thread_blocked in if-thread_in_native_trans check.
549 JavaThreadState save_state = thread_state();
550
551 if (save_state == _thread_blocked && is_suspend_equivalent()) {
552 // If the thread's state is _thread_blocked and this blocking
553 // condition is known to be equivalent to a suspend, then we can
554 // consider the thread to be externally suspended. This means that
555 // the code that sets _thread_blocked has been modified to do
556 // self-suspension if the blocking condition releases. We also
557 // used to check for CONDVAR_WAIT here, but that is now covered by
558 // the _thread_blocked with self-suspension check.
559 //
560 // Return true since we wouldn't be here unless there was still an
561 // external suspend request.
562 *bits |= 0x00001000;
563 return true;
564 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
565 // Threads running native code will self-suspend on native==>VM/Java
566 // transitions. If its stack is walkable (should always be the case
567 // unless this function is called before the actual java_suspend()
568 // call), then the wait is done.
569 *bits |= 0x00002000;
570 return true;
571 } else if (!called_by_wait && !did_trans_retry &&
572 save_state == _thread_in_native_trans &&
573 frame_anchor()->walkable()) {
574 // The thread is transitioning from thread_in_native to another
575 // thread state. check_safepoint_and_suspend_for_native_trans()
576 // will force the thread to self-suspend. If it hasn't gotten
577 // there yet we may have caught the thread in-between the native
578 // code check above and the self-suspend. Lucky us. If we were
579 // called by wait_for_ext_suspend_completion(), then it
580 // will be doing the retries so we don't have to.
581 //
582 // Since we use the saved thread state in the if-statement above,
583 // there is a chance that the thread has already transitioned to
584 // _thread_blocked by the time we get here. In that case, we will
585 // make a single unnecessary pass through the logic below. This
586 // doesn't hurt anything since we still do the trans retry.
587
588 *bits |= 0x00004000;
589
590 // Once the thread leaves thread_in_native_trans for another
591 // thread state, we break out of this retry loop. We shouldn't
592 // need this flag to prevent us from getting back here, but
593 // sometimes paranoia is good.
594 did_trans_retry = true;
595
596 // We wait for the thread to transition to a more usable state.
597 for (int i = 1; i <= SuspendRetryCount; i++) {
598 // We used to do an "os::yield_all(i)" call here with the intention
599 // that yielding would increase on each retry. However, the parameter
600 // is ignored on Linux which means the yield didn't scale up. Waiting
601 // on the SR_lock below provides a much more predictable scale up for
602 // the delay. It also provides a simple/direct point to check for any
603 // safepoint requests from the VMThread
604
605 // temporarily drops SR_lock while doing wait with safepoint check
606 // (if we're a JavaThread - the WatcherThread can also call this)
607 // and increase delay with each retry
608 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
609
610 // check the actual thread state instead of what we saved above
611 if (thread_state() != _thread_in_native_trans) {
612 // the thread has transitioned to another thread state so
613 // try all the checks (except this one) one more time.
614 do_trans_retry = true;
615 break;
616 }
617 } // end retry loop
618
619
620 }
621 } while (do_trans_retry);
622
623 *bits |= 0x00000010;
624 return false;
625 }
626
627 // Wait for an external suspend request to complete (or be cancelled).
628 // Returns true if the thread is externally suspended and false otherwise.
629 //
630 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
631 uint32_t *bits) {
632 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
633 false /* !called_by_wait */, bits);
634
635 // local flag copies to minimize SR_lock hold time
636 bool is_suspended;
637 bool pending;
638 uint32_t reset_bits;
639
640 // set a marker so is_ext_suspend_completed() knows we are the caller
641 *bits |= 0x00010000;
642
643 // We use reset_bits to reinitialize the bits value at the top of
644 // each retry loop. This allows the caller to make use of any
645 // unused bits for their own marking purposes.
646 reset_bits = *bits;
647
648 {
649 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
650 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
651 delay, bits);
652 pending = is_external_suspend();
653 }
654 // must release SR_lock to allow suspension to complete
655
656 if (!pending) {
657 // A cancelled suspend request is the only false return from
658 // is_ext_suspend_completed() that keeps us from entering the
659 // retry loop.
660 *bits |= 0x00020000;
661 return false;
662 }
663
664 if (is_suspended) {
665 *bits |= 0x00040000;
666 return true;
667 }
668
669 for (int i = 1; i <= retries; i++) {
670 *bits = reset_bits; // reinit to only track last retry
671
672 // We used to do an "os::yield_all(i)" call here with the intention
673 // that yielding would increase on each retry. However, the parameter
674 // is ignored on Linux which means the yield didn't scale up. Waiting
675 // on the SR_lock below provides a much more predictable scale up for
676 // the delay. It also provides a simple/direct point to check for any
677 // safepoint requests from the VMThread
678
679 {
680 MutexLocker ml(SR_lock());
681 // wait with safepoint check (if we're a JavaThread - the WatcherThread
682 // can also call this) and increase delay with each retry
683 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
684
685 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
686 delay, bits);
687
688 // It is possible for the external suspend request to be cancelled
689 // (by a resume) before the actual suspend operation is completed.
690 // Refresh our local copy to see if we still need to wait.
691 pending = is_external_suspend();
692 }
693
694 if (!pending) {
695 // A cancelled suspend request is the only false return from
696 // is_ext_suspend_completed() that keeps us from staying in the
697 // retry loop.
698 *bits |= 0x00080000;
699 return false;
700 }
701
702 if (is_suspended) {
703 *bits |= 0x00100000;
704 return true;
705 }
706 } // end retry loop
707
708 // thread did not suspend after all our retries
709 *bits |= 0x00200000;
710 return false;
711 }
712
713 #ifndef PRODUCT
714 void JavaThread::record_jump(address target, address instr, const char* file,
715 int line) {
716
717 // This should not need to be atomic as the only way for simultaneous
718 // updates is via interrupts. Even then this should be rare or non-existent
719 // and we don't care that much anyway.
720
721 int index = _jmp_ring_index;
722 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
723 _jmp_ring[index]._target = (intptr_t) target;
724 _jmp_ring[index]._instruction = (intptr_t) instr;
725 _jmp_ring[index]._file = file;
726 _jmp_ring[index]._line = line;
727 }
728 #endif // PRODUCT
729
730 // Called by flat profiler
731 // Callers have already called wait_for_ext_suspend_completion
732 // The assertion for that is currently too complex to put here:
733 bool JavaThread::profile_last_Java_frame(frame* _fr) {
734 bool gotframe = false;
735 // self suspension saves needed state.
736 if (has_last_Java_frame() && _anchor.walkable()) {
737 *_fr = pd_last_frame();
738 gotframe = true;
739 }
740 return gotframe;
741 }
742
743 void Thread::interrupt(Thread* thread) {
744 debug_only(check_for_dangling_thread_pointer(thread);)
745 os::interrupt(thread);
746 }
747
748 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
749 debug_only(check_for_dangling_thread_pointer(thread);)
750 // Note: If clear_interrupted==false, this simply fetches and
751 // returns the value of the field osthread()->interrupted().
752 return os::is_interrupted(thread, clear_interrupted);
753 }
754
755
756 // GC Support
757 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
758 jint thread_parity = _oops_do_parity;
759 if (thread_parity != strong_roots_parity) {
760 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
761 if (res == thread_parity) {
762 return true;
763 } else {
764 guarantee(res == strong_roots_parity, "Or else what?");
765 return false;
766 }
767 }
768 return false;
769 }
770
771 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
772 active_handles()->oops_do(f);
773 // Do oop for ThreadShadow
774 f->do_oop((oop*)&_pending_exception);
775 handle_area()->oops_do(f);
776 }
777
778 void Thread::nmethods_do(CodeBlobClosure* cf) {
779 // no nmethods in a generic thread...
780 }
781
782 void Thread::metadata_handles_do(void f(Metadata*)) {
783 // Only walk the Handles in Thread.
784 if (metadata_handles() != NULL) {
785 for (int i = 0; i< metadata_handles()->length(); i++) {
786 f(metadata_handles()->at(i));
787 }
788 }
789 }
790
791 void Thread::print_on(outputStream* st) const {
792 // get_priority assumes osthread initialized
793 if (osthread() != NULL) {
794 int os_prio;
795 if (os::get_native_priority(this, &os_prio) == OS_OK) {
796 st->print("os_prio=%d ", os_prio);
797 }
798 st->print("tid=" INTPTR_FORMAT " ", this);
799 ext().print_on(st);
800 osthread()->print_on(st);
801 }
802 debug_only(if (WizardMode) print_owned_locks_on(st);)
803 }
804
805 // Thread::print_on_error() is called by fatal error handler. Don't use
806 // any lock or allocate memory.
807 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
808 if (is_VM_thread()) st->print("VMThread");
809 else if (is_Compiler_thread()) st->print("CompilerThread");
810 else if (is_Java_thread()) st->print("JavaThread");
811 else if (is_GC_task_thread()) st->print("GCTaskThread");
812 else if (is_Watcher_thread()) st->print("WatcherThread");
813 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
814 else st->print("Thread");
815
816 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
817 _stack_base - _stack_size, _stack_base);
818
819 if (osthread()) {
820 st->print(" [id=%d]", osthread()->thread_id());
821 }
822 }
823
824 #ifdef ASSERT
825 void Thread::print_owned_locks_on(outputStream* st) const {
826 Monitor *cur = _owned_locks;
827 if (cur == NULL) {
828 st->print(" (no locks) ");
829 } else {
830 st->print_cr(" Locks owned:");
831 while (cur) {
832 cur->print_on(st);
833 cur = cur->next();
834 }
835 }
836 }
837
838 static int ref_use_count = 0;
839
840 bool Thread::owns_locks_but_compiled_lock() const {
841 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
842 if (cur != Compile_lock) return true;
843 }
844 return false;
845 }
846
847
848 #endif
849
850 #ifndef PRODUCT
851
852 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
853 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
854 // no threads which allow_vm_block's are held
855 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
856 // Check if current thread is allowed to block at a safepoint
857 if (!(_allow_safepoint_count == 0)) {
858 fatal("Possible safepoint reached by thread that does not allow it");
859 }
860 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
861 fatal("LEAF method calling lock?");
862 }
863
864 #ifdef ASSERT
865 if (potential_vm_operation && is_Java_thread()
866 && !Universe::is_bootstrapping()) {
867 // Make sure we do not hold any locks that the VM thread also uses.
868 // This could potentially lead to deadlocks
869 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
870 // Threads_lock is special, since the safepoint synchronization will not start before this is
871 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
872 // since it is used to transfer control between JavaThreads and the VMThread
873 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
874 if ((cur->allow_vm_block() &&
875 cur != Threads_lock &&
876 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
877 cur != VMOperationRequest_lock &&
878 cur != VMOperationQueue_lock) ||
879 cur->rank() == Mutex::special) {
880 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
881 }
882 }
883 }
884
885 if (GCALotAtAllSafepoints) {
886 // We could enter a safepoint here and thus have a gc
887 InterfaceSupport::check_gc_alot();
888 }
889 #endif
890 }
891 #endif
892
893 bool Thread::is_in_stack(address adr) const {
894 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
895 address end = os::current_stack_pointer();
896 // Allow non Java threads to call this without stack_base
897 if (_stack_base == NULL) return true;
898 if (stack_base() >= adr && adr >= end) return true;
899
900 return false;
901 }
902
903
904 bool Thread::is_in_usable_stack(address adr) const {
905 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
906 size_t usable_stack_size = _stack_size - stack_guard_size;
907
908 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
909 }
910
911
912 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
913 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
914 // used for compilation in the future. If that change is made, the need for these methods
915 // should be revisited, and they should be removed if possible.
916
917 bool Thread::is_lock_owned(address adr) const {
918 return on_local_stack(adr);
919 }
920
921 bool Thread::set_as_starting_thread() {
922 // NOTE: this must be called inside the main thread.
923 return os::create_main_thread((JavaThread*)this);
924 }
925
926 static void initialize_class(Symbol* class_name, TRAPS) {
927 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
928 InstanceKlass::cast(klass)->initialize(CHECK);
929 }
930
931
932 // Creates the initial ThreadGroup
933 static Handle create_initial_thread_group(TRAPS) {
934 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
935 instanceKlassHandle klass (THREAD, k);
936
937 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
938 {
939 JavaValue result(T_VOID);
940 JavaCalls::call_special(&result,
941 system_instance,
942 klass,
943 vmSymbols::object_initializer_name(),
944 vmSymbols::void_method_signature(),
945 CHECK_NH);
946 }
947 Universe::set_system_thread_group(system_instance());
948
949 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
950 {
951 JavaValue result(T_VOID);
952 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
953 JavaCalls::call_special(&result,
954 main_instance,
955 klass,
956 vmSymbols::object_initializer_name(),
957 vmSymbols::threadgroup_string_void_signature(),
958 system_instance,
959 string,
960 CHECK_NH);
961 }
962 return main_instance;
963 }
964
965 // Creates the initial Thread
966 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
967 TRAPS) {
968 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
969 instanceKlassHandle klass (THREAD, k);
970 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
971
972 java_lang_Thread::set_thread(thread_oop(), thread);
973 java_lang_Thread::set_priority(thread_oop(), NormPriority);
974 thread->set_threadObj(thread_oop());
975
976 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
977
978 JavaValue result(T_VOID);
979 JavaCalls::call_special(&result, thread_oop,
980 klass,
981 vmSymbols::object_initializer_name(),
982 vmSymbols::threadgroup_string_void_signature(),
983 thread_group,
984 string,
985 CHECK_NULL);
986 return thread_oop();
987 }
988
989 static void call_initializeSystemClass(TRAPS) {
990 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
991 instanceKlassHandle klass (THREAD, k);
992
993 JavaValue result(T_VOID);
994 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
995 vmSymbols::void_method_signature(), CHECK);
996 }
997
998 char java_runtime_name[128] = "";
999 char java_runtime_version[128] = "";
1000
1001 // extract the JRE name from sun.misc.Version.java_runtime_name
1002 static const char* get_java_runtime_name(TRAPS) {
1003 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1004 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1005 fieldDescriptor fd;
1006 bool found = k != NULL &&
1007 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1008 vmSymbols::string_signature(), &fd);
1009 if (found) {
1010 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1011 if (name_oop == NULL) {
1012 return NULL;
1013 }
1014 const char* name = java_lang_String::as_utf8_string(name_oop,
1015 java_runtime_name,
1016 sizeof(java_runtime_name));
1017 return name;
1018 } else {
1019 return NULL;
1020 }
1021 }
1022
1023 // extract the JRE version from sun.misc.Version.java_runtime_version
1024 static const char* get_java_runtime_version(TRAPS) {
1025 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1026 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1027 fieldDescriptor fd;
1028 bool found = k != NULL &&
1029 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1030 vmSymbols::string_signature(), &fd);
1031 if (found) {
1032 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1033 if (name_oop == NULL) {
1034 return NULL;
1035 }
1036 const char* name = java_lang_String::as_utf8_string(name_oop,
1037 java_runtime_version,
1038 sizeof(java_runtime_version));
1039 return name;
1040 } else {
1041 return NULL;
1042 }
1043 }
1044
1045 // General purpose hook into Java code, run once when the VM is initialized.
1046 // The Java library method itself may be changed independently from the VM.
1047 static void call_postVMInitHook(TRAPS) {
1048 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1049 instanceKlassHandle klass (THREAD, k);
1050 if (klass.not_null()) {
1051 JavaValue result(T_VOID);
1052 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1053 vmSymbols::void_method_signature(),
1054 CHECK);
1055 }
1056 }
1057
1058 static void reset_vm_info_property(TRAPS) {
1059 // the vm info string
1060 ResourceMark rm(THREAD);
1061 const char *vm_info = VM_Version::vm_info_string();
1062
1063 // java.lang.System class
1064 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1065 instanceKlassHandle klass (THREAD, k);
1066
1067 // setProperty arguments
1068 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1069 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1070
1071 // return value
1072 JavaValue r(T_OBJECT);
1073
1074 // public static String setProperty(String key, String value);
1075 JavaCalls::call_static(&r,
1076 klass,
1077 vmSymbols::setProperty_name(),
1078 vmSymbols::string_string_string_signature(),
1079 key_str,
1080 value_str,
1081 CHECK);
1082 }
1083
1084
1085 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1086 bool daemon, TRAPS) {
1087 assert(thread_group.not_null(), "thread group should be specified");
1088 assert(threadObj() == NULL, "should only create Java thread object once");
1089
1090 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1091 instanceKlassHandle klass (THREAD, k);
1092 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1093
1094 java_lang_Thread::set_thread(thread_oop(), this);
1095 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1096 set_threadObj(thread_oop());
1097
1098 JavaValue result(T_VOID);
1099 if (thread_name != NULL) {
1100 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1101 // Thread gets assigned specified name and null target
1102 JavaCalls::call_special(&result,
1103 thread_oop,
1104 klass,
1105 vmSymbols::object_initializer_name(),
1106 vmSymbols::threadgroup_string_void_signature(),
1107 thread_group, // Argument 1
1108 name, // Argument 2
1109 THREAD);
1110 } else {
1111 // Thread gets assigned name "Thread-nnn" and null target
1112 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1113 JavaCalls::call_special(&result,
1114 thread_oop,
1115 klass,
1116 vmSymbols::object_initializer_name(),
1117 vmSymbols::threadgroup_runnable_void_signature(),
1118 thread_group, // Argument 1
1119 Handle(), // Argument 2
1120 THREAD);
1121 }
1122
1123
1124 if (daemon) {
1125 java_lang_Thread::set_daemon(thread_oop());
1126 }
1127
1128 if (HAS_PENDING_EXCEPTION) {
1129 return;
1130 }
1131
1132 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1133 Handle threadObj(THREAD, this->threadObj());
1134
1135 JavaCalls::call_special(&result,
1136 thread_group,
1137 group,
1138 vmSymbols::add_method_name(),
1139 vmSymbols::thread_void_signature(),
1140 threadObj, // Arg 1
1141 THREAD);
1142 }
1143
1144 // NamedThread -- non-JavaThread subclasses with multiple
1145 // uniquely named instances should derive from this.
1146 NamedThread::NamedThread() : Thread() {
1147 _name = NULL;
1148 _processed_thread = NULL;
1149 }
1150
1151 NamedThread::~NamedThread() {
1152 if (_name != NULL) {
1153 FREE_C_HEAP_ARRAY(char, _name);
1154 _name = NULL;
1155 }
1156 }
1157
1158 void NamedThread::set_name(const char* format, ...) {
1159 guarantee(_name == NULL, "Only get to set name once.");
1160 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1161 guarantee(_name != NULL, "alloc failure");
1162 va_list ap;
1163 va_start(ap, format);
1164 jio_vsnprintf(_name, max_name_len, format, ap);
1165 va_end(ap);
1166 }
1167
1168 void NamedThread::initialize_named_thread() {
1169 set_native_thread_name(name());
1170 }
1171
1172 void NamedThread::print_on(outputStream* st) const {
1173 st->print("\"%s\" ", name());
1174 Thread::print_on(st);
1175 st->cr();
1176 }
1177
1178
1179 // ======= WatcherThread ========
1180
1181 // The watcher thread exists to simulate timer interrupts. It should
1182 // be replaced by an abstraction over whatever native support for
1183 // timer interrupts exists on the platform.
1184
1185 WatcherThread* WatcherThread::_watcher_thread = NULL;
1186 bool WatcherThread::_startable = false;
1187 volatile bool WatcherThread::_should_terminate = false;
1188
1189 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1190 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1191 if (os::create_thread(this, os::watcher_thread)) {
1192 _watcher_thread = this;
1193
1194 // Set the watcher thread to the highest OS priority which should not be
1195 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1196 // is created. The only normal thread using this priority is the reference
1197 // handler thread, which runs for very short intervals only.
1198 // If the VMThread's priority is not lower than the WatcherThread profiling
1199 // will be inaccurate.
1200 os::set_priority(this, MaxPriority);
1201 if (!DisableStartThread) {
1202 os::start_thread(this);
1203 }
1204 }
1205 }
1206
1207 int WatcherThread::sleep() const {
1208 // The WatcherThread does not participate in the safepoint protocol
1209 // for the PeriodicTask_lock because it is not a JavaThread.
1210 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1211
1212 if (_should_terminate) {
1213 // check for termination before we do any housekeeping or wait
1214 return 0; // we did not sleep.
1215 }
1216
1217 // remaining will be zero if there are no tasks,
1218 // causing the WatcherThread to sleep until a task is
1219 // enrolled
1220 int remaining = PeriodicTask::time_to_wait();
1221 int time_slept = 0;
1222
1223 // we expect this to timeout - we only ever get unparked when
1224 // we should terminate or when a new task has been enrolled
1225 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1226
1227 jlong time_before_loop = os::javaTimeNanos();
1228
1229 while (true) {
1230 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1231 remaining);
1232 jlong now = os::javaTimeNanos();
1233
1234 if (remaining == 0) {
1235 // if we didn't have any tasks we could have waited for a long time
1236 // consider the time_slept zero and reset time_before_loop
1237 time_slept = 0;
1238 time_before_loop = now;
1239 } else {
1240 // need to recalculate since we might have new tasks in _tasks
1241 time_slept = (int) ((now - time_before_loop) / 1000000);
1242 }
1243
1244 // Change to task list or spurious wakeup of some kind
1245 if (timedout || _should_terminate) {
1246 break;
1247 }
1248
1249 remaining = PeriodicTask::time_to_wait();
1250 if (remaining == 0) {
1251 // Last task was just disenrolled so loop around and wait until
1252 // another task gets enrolled
1253 continue;
1254 }
1255
1256 remaining -= time_slept;
1257 if (remaining <= 0) {
1258 break;
1259 }
1260 }
1261
1262 return time_slept;
1263 }
1264
1265 void WatcherThread::run() {
1266 assert(this == watcher_thread(), "just checking");
1267
1268 this->record_stack_base_and_size();
1269 this->initialize_thread_local_storage();
1270 this->set_native_thread_name(this->name());
1271 this->set_active_handles(JNIHandleBlock::allocate_block());
1272 while (true) {
1273 assert(watcher_thread() == Thread::current(), "thread consistency check");
1274 assert(watcher_thread() == this, "thread consistency check");
1275
1276 // Calculate how long it'll be until the next PeriodicTask work
1277 // should be done, and sleep that amount of time.
1278 int time_waited = sleep();
1279
1280 if (is_error_reported()) {
1281 // A fatal error has happened, the error handler(VMError::report_and_die)
1282 // should abort JVM after creating an error log file. However in some
1283 // rare cases, the error handler itself might deadlock. Here we try to
1284 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1285 //
1286 // This code is in WatcherThread because WatcherThread wakes up
1287 // periodically so the fatal error handler doesn't need to do anything;
1288 // also because the WatcherThread is less likely to crash than other
1289 // threads.
1290
1291 for (;;) {
1292 if (!ShowMessageBoxOnError
1293 && (OnError == NULL || OnError[0] == '\0')
1294 && Arguments::abort_hook() == NULL) {
1295 os::sleep(this, ErrorLogTimeout * 60 * 1000, false);
1296 fdStream err(defaultStream::output_fd());
1297 err.print_raw_cr("# [ timer expired, abort... ]");
1298 // skip atexit/vm_exit/vm_abort hooks
1299 os::die();
1300 }
1301
1302 // Wake up 5 seconds later, the fatal handler may reset OnError or
1303 // ShowMessageBoxOnError when it is ready to abort.
1304 os::sleep(this, 5 * 1000, false);
1305 }
1306 }
1307
1308 if (_should_terminate) {
1309 // check for termination before posting the next tick
1310 break;
1311 }
1312
1313 PeriodicTask::real_time_tick(time_waited);
1314 }
1315
1316 // Signal that it is terminated
1317 {
1318 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1319 _watcher_thread = NULL;
1320 Terminator_lock->notify();
1321 }
1322
1323 // Thread destructor usually does this..
1324 ThreadLocalStorage::set_thread(NULL);
1325 }
1326
1327 void WatcherThread::start() {
1328 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1329
1330 if (watcher_thread() == NULL && _startable) {
1331 _should_terminate = false;
1332 // Create the single instance of WatcherThread
1333 new WatcherThread();
1334 }
1335 }
1336
1337 void WatcherThread::make_startable() {
1338 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1339 _startable = true;
1340 }
1341
1342 void WatcherThread::stop() {
1343 {
1344 // Follow normal safepoint aware lock enter protocol since the
1345 // WatcherThread is stopped by another JavaThread.
1346 MutexLocker ml(PeriodicTask_lock);
1347 _should_terminate = true;
1348
1349 WatcherThread* watcher = watcher_thread();
1350 if (watcher != NULL) {
1351 // unpark the WatcherThread so it can see that it should terminate
1352 watcher->unpark();
1353 }
1354 }
1355
1356 MutexLocker mu(Terminator_lock);
1357
1358 while (watcher_thread() != NULL) {
1359 // This wait should make safepoint checks, wait without a timeout,
1360 // and wait as a suspend-equivalent condition.
1361 //
1362 // Note: If the FlatProfiler is running, then this thread is waiting
1363 // for the WatcherThread to terminate and the WatcherThread, via the
1364 // FlatProfiler task, is waiting for the external suspend request on
1365 // this thread to complete. wait_for_ext_suspend_completion() will
1366 // eventually timeout, but that takes time. Making this wait a
1367 // suspend-equivalent condition solves that timeout problem.
1368 //
1369 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1370 Mutex::_as_suspend_equivalent_flag);
1371 }
1372 }
1373
1374 void WatcherThread::unpark() {
1375 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1376 PeriodicTask_lock->notify();
1377 }
1378
1379 void WatcherThread::print_on(outputStream* st) const {
1380 st->print("\"%s\" ", name());
1381 Thread::print_on(st);
1382 st->cr();
1383 }
1384
1385 // ======= JavaThread ========
1386
1387 // A JavaThread is a normal Java thread
1388
1389 void JavaThread::initialize() {
1390 // Initialize fields
1391
1392 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1393 set_claimed_par_id(UINT_MAX);
1394
1395 set_saved_exception_pc(NULL);
1396 set_threadObj(NULL);
1397 _anchor.clear();
1398 set_entry_point(NULL);
1399 set_jni_functions(jni_functions());
1400 set_callee_target(NULL);
1401 set_vm_result(NULL);
1402 set_vm_result_2(NULL);
1403 set_vframe_array_head(NULL);
1404 set_vframe_array_last(NULL);
1405 set_deferred_locals(NULL);
1406 set_deopt_mark(NULL);
1407 set_deopt_nmethod(NULL);
1408 clear_must_deopt_id();
1409 set_monitor_chunks(NULL);
1410 set_next(NULL);
1411 set_thread_state(_thread_new);
1412 _terminated = _not_terminated;
1413 _privileged_stack_top = NULL;
1414 _array_for_gc = NULL;
1415 _suspend_equivalent = false;
1416 _in_deopt_handler = 0;
1417 _doing_unsafe_access = false;
1418 _stack_guard_state = stack_guard_unused;
1419 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1420 _exception_pc = 0;
1421 _exception_handler_pc = 0;
1422 _is_method_handle_return = 0;
1423 _jvmti_thread_state= NULL;
1424 _should_post_on_exceptions_flag = JNI_FALSE;
1425 _jvmti_get_loaded_classes_closure = NULL;
1426 _interp_only_mode = 0;
1427 _special_runtime_exit_condition = _no_async_condition;
1428 _pending_async_exception = NULL;
1429 _thread_stat = NULL;
1430 _thread_stat = new ThreadStatistics();
1431 _blocked_on_compilation = false;
1432 _jni_active_critical = 0;
1433 _pending_jni_exception_check_fn = NULL;
1434 _do_not_unlock_if_synchronized = false;
1435 _cached_monitor_info = NULL;
1436 _parker = Parker::Allocate(this);
1437
1438 #ifndef PRODUCT
1439 _jmp_ring_index = 0;
1440 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1441 record_jump(NULL, NULL, NULL, 0);
1442 }
1443 #endif // PRODUCT
1444
1445 set_thread_profiler(NULL);
1446 if (FlatProfiler::is_active()) {
1447 // This is where we would decide to either give each thread it's own profiler
1448 // or use one global one from FlatProfiler,
1449 // or up to some count of the number of profiled threads, etc.
1450 ThreadProfiler* pp = new ThreadProfiler();
1451 pp->engage();
1452 set_thread_profiler(pp);
1453 }
1454
1455 // Setup safepoint state info for this thread
1456 ThreadSafepointState::create(this);
1457
1458 debug_only(_java_call_counter = 0);
1459
1460 // JVMTI PopFrame support
1461 _popframe_condition = popframe_inactive;
1462 _popframe_preserved_args = NULL;
1463 _popframe_preserved_args_size = 0;
1464 _frames_to_pop_failed_realloc = 0;
1465
1466 pd_initialize();
1467 }
1468
1469 #if INCLUDE_ALL_GCS
1470 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1471 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1472 #endif // INCLUDE_ALL_GCS
1473
1474 JavaThread::JavaThread(bool is_attaching_via_jni) :
1475 Thread()
1476 #if INCLUDE_ALL_GCS
1477 , _satb_mark_queue(&_satb_mark_queue_set),
1478 _dirty_card_queue(&_dirty_card_queue_set)
1479 #endif // INCLUDE_ALL_GCS
1480 {
1481 initialize();
1482 if (is_attaching_via_jni) {
1483 _jni_attach_state = _attaching_via_jni;
1484 } else {
1485 _jni_attach_state = _not_attaching_via_jni;
1486 }
1487 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1488 }
1489
1490 bool JavaThread::reguard_stack(address cur_sp) {
1491 if (_stack_guard_state != stack_guard_yellow_disabled) {
1492 return true; // Stack already guarded or guard pages not needed.
1493 }
1494
1495 if (register_stack_overflow()) {
1496 // For those architectures which have separate register and
1497 // memory stacks, we must check the register stack to see if
1498 // it has overflowed.
1499 return false;
1500 }
1501
1502 // Java code never executes within the yellow zone: the latter is only
1503 // there to provoke an exception during stack banging. If java code
1504 // is executing there, either StackShadowPages should be larger, or
1505 // some exception code in c1, c2 or the interpreter isn't unwinding
1506 // when it should.
1507 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1508
1509 enable_stack_yellow_zone();
1510 return true;
1511 }
1512
1513 bool JavaThread::reguard_stack(void) {
1514 return reguard_stack(os::current_stack_pointer());
1515 }
1516
1517
1518 void JavaThread::block_if_vm_exited() {
1519 if (_terminated == _vm_exited) {
1520 // _vm_exited is set at safepoint, and Threads_lock is never released
1521 // we will block here forever
1522 Threads_lock->lock_without_safepoint_check();
1523 ShouldNotReachHere();
1524 }
1525 }
1526
1527
1528 // Remove this ifdef when C1 is ported to the compiler interface.
1529 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1530 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1531
1532 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1533 Thread()
1534 #if INCLUDE_ALL_GCS
1535 , _satb_mark_queue(&_satb_mark_queue_set),
1536 _dirty_card_queue(&_dirty_card_queue_set)
1537 #endif // INCLUDE_ALL_GCS
1538 {
1539 initialize();
1540 _jni_attach_state = _not_attaching_via_jni;
1541 set_entry_point(entry_point);
1542 // Create the native thread itself.
1543 // %note runtime_23
1544 os::ThreadType thr_type = os::java_thread;
1545 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1546 os::java_thread;
1547 os::create_thread(this, thr_type, stack_sz);
1548 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1549 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1550 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1551 // the exception consists of creating the exception object & initializing it, initialization
1552 // will leave the VM via a JavaCall and then all locks must be unlocked).
1553 //
1554 // The thread is still suspended when we reach here. Thread must be explicit started
1555 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1556 // by calling Threads:add. The reason why this is not done here, is because the thread
1557 // object must be fully initialized (take a look at JVM_Start)
1558 }
1559
1560 JavaThread::~JavaThread() {
1561
1562 // JSR166 -- return the parker to the free list
1563 Parker::Release(_parker);
1564 _parker = NULL;
1565
1566 // Free any remaining previous UnrollBlock
1567 vframeArray* old_array = vframe_array_last();
1568
1569 if (old_array != NULL) {
1570 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1571 old_array->set_unroll_block(NULL);
1572 delete old_info;
1573 delete old_array;
1574 }
1575
1576 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1577 if (deferred != NULL) {
1578 // This can only happen if thread is destroyed before deoptimization occurs.
1579 assert(deferred->length() != 0, "empty array!");
1580 do {
1581 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1582 deferred->remove_at(0);
1583 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1584 delete dlv;
1585 } while (deferred->length() != 0);
1586 delete deferred;
1587 }
1588
1589 // All Java related clean up happens in exit
1590 ThreadSafepointState::destroy(this);
1591 if (_thread_profiler != NULL) delete _thread_profiler;
1592 if (_thread_stat != NULL) delete _thread_stat;
1593 }
1594
1595
1596 // The first routine called by a new Java thread
1597 void JavaThread::run() {
1598 // initialize thread-local alloc buffer related fields
1599 this->initialize_tlab();
1600
1601 // used to test validity of stack trace backs
1602 this->record_base_of_stack_pointer();
1603
1604 // Record real stack base and size.
1605 this->record_stack_base_and_size();
1606
1607 // Initialize thread local storage; set before calling MutexLocker
1608 this->initialize_thread_local_storage();
1609
1610 this->create_stack_guard_pages();
1611
1612 this->cache_global_variables();
1613
1614 // Thread is now sufficient initialized to be handled by the safepoint code as being
1615 // in the VM. Change thread state from _thread_new to _thread_in_vm
1616 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1617
1618 assert(JavaThread::current() == this, "sanity check");
1619 assert(!Thread::current()->owns_locks(), "sanity check");
1620
1621 DTRACE_THREAD_PROBE(start, this);
1622
1623 // This operation might block. We call that after all safepoint checks for a new thread has
1624 // been completed.
1625 this->set_active_handles(JNIHandleBlock::allocate_block());
1626
1627 if (JvmtiExport::should_post_thread_life()) {
1628 JvmtiExport::post_thread_start(this);
1629 }
1630
1631 EventThreadStart event;
1632 if (event.should_commit()) {
1633 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1634 event.commit();
1635 }
1636
1637 // We call another function to do the rest so we are sure that the stack addresses used
1638 // from there will be lower than the stack base just computed
1639 thread_main_inner();
1640
1641 // Note, thread is no longer valid at this point!
1642 }
1643
1644
1645 void JavaThread::thread_main_inner() {
1646 assert(JavaThread::current() == this, "sanity check");
1647 assert(this->threadObj() != NULL, "just checking");
1648
1649 // Execute thread entry point unless this thread has a pending exception
1650 // or has been stopped before starting.
1651 // Note: Due to JVM_StopThread we can have pending exceptions already!
1652 if (!this->has_pending_exception() &&
1653 !java_lang_Thread::is_stillborn(this->threadObj())) {
1654 {
1655 ResourceMark rm(this);
1656 this->set_native_thread_name(this->get_thread_name());
1657 }
1658 HandleMark hm(this);
1659 this->entry_point()(this, this);
1660 }
1661
1662 DTRACE_THREAD_PROBE(stop, this);
1663
1664 this->exit(false);
1665 delete this;
1666 }
1667
1668
1669 static void ensure_join(JavaThread* thread) {
1670 // We do not need to grap the Threads_lock, since we are operating on ourself.
1671 Handle threadObj(thread, thread->threadObj());
1672 assert(threadObj.not_null(), "java thread object must exist");
1673 ObjectLocker lock(threadObj, thread);
1674 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1675 thread->clear_pending_exception();
1676 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1677 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1678 // Clear the native thread instance - this makes isAlive return false and allows the join()
1679 // to complete once we've done the notify_all below
1680 java_lang_Thread::set_thread(threadObj(), NULL);
1681 lock.notify_all(thread);
1682 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1683 thread->clear_pending_exception();
1684 }
1685
1686
1687 // For any new cleanup additions, please check to see if they need to be applied to
1688 // cleanup_failed_attach_current_thread as well.
1689 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1690 assert(this == JavaThread::current(), "thread consistency check");
1691
1692 HandleMark hm(this);
1693 Handle uncaught_exception(this, this->pending_exception());
1694 this->clear_pending_exception();
1695 Handle threadObj(this, this->threadObj());
1696 assert(threadObj.not_null(), "Java thread object should be created");
1697
1698 if (get_thread_profiler() != NULL) {
1699 get_thread_profiler()->disengage();
1700 ResourceMark rm;
1701 get_thread_profiler()->print(get_thread_name());
1702 }
1703
1704
1705 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1706 {
1707 EXCEPTION_MARK;
1708
1709 CLEAR_PENDING_EXCEPTION;
1710 }
1711 if (!destroy_vm) {
1712 if (uncaught_exception.not_null()) {
1713 EXCEPTION_MARK;
1714 // Call method Thread.dispatchUncaughtException().
1715 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1716 JavaValue result(T_VOID);
1717 JavaCalls::call_virtual(&result,
1718 threadObj, thread_klass,
1719 vmSymbols::dispatchUncaughtException_name(),
1720 vmSymbols::throwable_void_signature(),
1721 uncaught_exception,
1722 THREAD);
1723 if (HAS_PENDING_EXCEPTION) {
1724 ResourceMark rm(this);
1725 jio_fprintf(defaultStream::error_stream(),
1726 "\nException: %s thrown from the UncaughtExceptionHandler"
1727 " in thread \"%s\"\n",
1728 pending_exception()->klass()->external_name(),
1729 get_thread_name());
1730 CLEAR_PENDING_EXCEPTION;
1731 }
1732 }
1733
1734 // Called before the java thread exit since we want to read info
1735 // from java_lang_Thread object
1736 EventThreadEnd event;
1737 if (event.should_commit()) {
1738 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1739 event.commit();
1740 }
1741
1742 // Call after last event on thread
1743 EVENT_THREAD_EXIT(this);
1744
1745 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1746 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1747 // is deprecated anyhow.
1748 if (!is_Compiler_thread()) {
1749 int count = 3;
1750 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1751 EXCEPTION_MARK;
1752 JavaValue result(T_VOID);
1753 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1754 JavaCalls::call_virtual(&result,
1755 threadObj, thread_klass,
1756 vmSymbols::exit_method_name(),
1757 vmSymbols::void_method_signature(),
1758 THREAD);
1759 CLEAR_PENDING_EXCEPTION;
1760 }
1761 }
1762 // notify JVMTI
1763 if (JvmtiExport::should_post_thread_life()) {
1764 JvmtiExport::post_thread_end(this);
1765 }
1766
1767 // We have notified the agents that we are exiting, before we go on,
1768 // we must check for a pending external suspend request and honor it
1769 // in order to not surprise the thread that made the suspend request.
1770 while (true) {
1771 {
1772 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1773 if (!is_external_suspend()) {
1774 set_terminated(_thread_exiting);
1775 ThreadService::current_thread_exiting(this);
1776 break;
1777 }
1778 // Implied else:
1779 // Things get a little tricky here. We have a pending external
1780 // suspend request, but we are holding the SR_lock so we
1781 // can't just self-suspend. So we temporarily drop the lock
1782 // and then self-suspend.
1783 }
1784
1785 ThreadBlockInVM tbivm(this);
1786 java_suspend_self();
1787
1788 // We're done with this suspend request, but we have to loop around
1789 // and check again. Eventually we will get SR_lock without a pending
1790 // external suspend request and will be able to mark ourselves as
1791 // exiting.
1792 }
1793 // no more external suspends are allowed at this point
1794 } else {
1795 // before_exit() has already posted JVMTI THREAD_END events
1796 }
1797
1798 // Notify waiters on thread object. This has to be done after exit() is called
1799 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1800 // group should have the destroyed bit set before waiters are notified).
1801 ensure_join(this);
1802 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1803
1804 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1805 // held by this thread must be released. A detach operation must only
1806 // get here if there are no Java frames on the stack. Therefore, any
1807 // owned monitors at this point MUST be JNI-acquired monitors which are
1808 // pre-inflated and in the monitor cache.
1809 //
1810 // Optionally release any monitors for regular JavaThread exits. This
1811 // is provided as a work around for any bugs in monitor enter-exit
1812 // matching. This can be expensive so it is not enabled by default.
1813 //
1814 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1815 // ObjectSynchronizer::release_monitors_owned_by_thread().
1816 if ((exit_type == jni_detach && JNIDetachReleasesMonitors) ||
1817 JavaThreadExitReleasesMonitors) {
1818 assert(!this->has_last_Java_frame(),
1819 "should not have a Java frame when detaching or exiting");
1820 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1821 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1822 }
1823
1824 // These things needs to be done while we are still a Java Thread. Make sure that thread
1825 // is in a consistent state, in case GC happens
1826 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1827
1828 if (active_handles() != NULL) {
1829 JNIHandleBlock* block = active_handles();
1830 set_active_handles(NULL);
1831 JNIHandleBlock::release_block(block);
1832 }
1833
1834 if (free_handle_block() != NULL) {
1835 JNIHandleBlock* block = free_handle_block();
1836 set_free_handle_block(NULL);
1837 JNIHandleBlock::release_block(block);
1838 }
1839
1840 // These have to be removed while this is still a valid thread.
1841 remove_stack_guard_pages();
1842
1843 if (UseTLAB) {
1844 tlab().make_parsable(true); // retire TLAB
1845 }
1846
1847 if (JvmtiEnv::environments_might_exist()) {
1848 JvmtiExport::cleanup_thread(this);
1849 }
1850
1851 // We must flush any deferred card marks before removing a thread from
1852 // the list of active threads.
1853 Universe::heap()->flush_deferred_store_barrier(this);
1854 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1855
1856 #if INCLUDE_ALL_GCS
1857 // We must flush the G1-related buffers before removing a thread
1858 // from the list of active threads. We must do this after any deferred
1859 // card marks have been flushed (above) so that any entries that are
1860 // added to the thread's dirty card queue as a result are not lost.
1861 if (UseG1GC) {
1862 flush_barrier_queues();
1863 }
1864 #endif // INCLUDE_ALL_GCS
1865
1866 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1867 Threads::remove(this);
1868 }
1869
1870 #if INCLUDE_ALL_GCS
1871 // Flush G1-related queues.
1872 void JavaThread::flush_barrier_queues() {
1873 satb_mark_queue().flush();
1874 dirty_card_queue().flush();
1875 }
1876
1877 void JavaThread::initialize_queues() {
1878 assert(!SafepointSynchronize::is_at_safepoint(),
1879 "we should not be at a safepoint");
1880
1881 ObjPtrQueue& satb_queue = satb_mark_queue();
1882 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1883 // The SATB queue should have been constructed with its active
1884 // field set to false.
1885 assert(!satb_queue.is_active(), "SATB queue should not be active");
1886 assert(satb_queue.is_empty(), "SATB queue should be empty");
1887 // If we are creating the thread during a marking cycle, we should
1888 // set the active field of the SATB queue to true.
1889 if (satb_queue_set.is_active()) {
1890 satb_queue.set_active(true);
1891 }
1892
1893 DirtyCardQueue& dirty_queue = dirty_card_queue();
1894 // The dirty card queue should have been constructed with its
1895 // active field set to true.
1896 assert(dirty_queue.is_active(), "dirty card queue should be active");
1897 }
1898 #endif // INCLUDE_ALL_GCS
1899
1900 void JavaThread::cleanup_failed_attach_current_thread() {
1901 if (get_thread_profiler() != NULL) {
1902 get_thread_profiler()->disengage();
1903 ResourceMark rm;
1904 get_thread_profiler()->print(get_thread_name());
1905 }
1906
1907 if (active_handles() != NULL) {
1908 JNIHandleBlock* block = active_handles();
1909 set_active_handles(NULL);
1910 JNIHandleBlock::release_block(block);
1911 }
1912
1913 if (free_handle_block() != NULL) {
1914 JNIHandleBlock* block = free_handle_block();
1915 set_free_handle_block(NULL);
1916 JNIHandleBlock::release_block(block);
1917 }
1918
1919 // These have to be removed while this is still a valid thread.
1920 remove_stack_guard_pages();
1921
1922 if (UseTLAB) {
1923 tlab().make_parsable(true); // retire TLAB, if any
1924 }
1925
1926 #if INCLUDE_ALL_GCS
1927 if (UseG1GC) {
1928 flush_barrier_queues();
1929 }
1930 #endif // INCLUDE_ALL_GCS
1931
1932 Threads::remove(this);
1933 delete this;
1934 }
1935
1936
1937
1938
1939 JavaThread* JavaThread::active() {
1940 Thread* thread = ThreadLocalStorage::thread();
1941 assert(thread != NULL, "just checking");
1942 if (thread->is_Java_thread()) {
1943 return (JavaThread*) thread;
1944 } else {
1945 assert(thread->is_VM_thread(), "this must be a vm thread");
1946 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1947 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1948 assert(ret->is_Java_thread(), "must be a Java thread");
1949 return ret;
1950 }
1951 }
1952
1953 bool JavaThread::is_lock_owned(address adr) const {
1954 if (Thread::is_lock_owned(adr)) return true;
1955
1956 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1957 if (chunk->contains(adr)) return true;
1958 }
1959
1960 return false;
1961 }
1962
1963
1964 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1965 chunk->set_next(monitor_chunks());
1966 set_monitor_chunks(chunk);
1967 }
1968
1969 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1970 guarantee(monitor_chunks() != NULL, "must be non empty");
1971 if (monitor_chunks() == chunk) {
1972 set_monitor_chunks(chunk->next());
1973 } else {
1974 MonitorChunk* prev = monitor_chunks();
1975 while (prev->next() != chunk) prev = prev->next();
1976 prev->set_next(chunk->next());
1977 }
1978 }
1979
1980 // JVM support.
1981
1982 // Note: this function shouldn't block if it's called in
1983 // _thread_in_native_trans state (such as from
1984 // check_special_condition_for_native_trans()).
1985 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1986
1987 if (has_last_Java_frame() && has_async_condition()) {
1988 // If we are at a polling page safepoint (not a poll return)
1989 // then we must defer async exception because live registers
1990 // will be clobbered by the exception path. Poll return is
1991 // ok because the call we a returning from already collides
1992 // with exception handling registers and so there is no issue.
1993 // (The exception handling path kills call result registers but
1994 // this is ok since the exception kills the result anyway).
1995
1996 if (is_at_poll_safepoint()) {
1997 // if the code we are returning to has deoptimized we must defer
1998 // the exception otherwise live registers get clobbered on the
1999 // exception path before deoptimization is able to retrieve them.
2000 //
2001 RegisterMap map(this, false);
2002 frame caller_fr = last_frame().sender(&map);
2003 assert(caller_fr.is_compiled_frame(), "what?");
2004 if (caller_fr.is_deoptimized_frame()) {
2005 if (TraceExceptions) {
2006 ResourceMark rm;
2007 tty->print_cr("deferred async exception at compiled safepoint");
2008 }
2009 return;
2010 }
2011 }
2012 }
2013
2014 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2015 if (condition == _no_async_condition) {
2016 // Conditions have changed since has_special_runtime_exit_condition()
2017 // was called:
2018 // - if we were here only because of an external suspend request,
2019 // then that was taken care of above (or cancelled) so we are done
2020 // - if we were here because of another async request, then it has
2021 // been cleared between the has_special_runtime_exit_condition()
2022 // and now so again we are done
2023 return;
2024 }
2025
2026 // Check for pending async. exception
2027 if (_pending_async_exception != NULL) {
2028 // Only overwrite an already pending exception, if it is not a threadDeath.
2029 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2030
2031 // We cannot call Exceptions::_throw(...) here because we cannot block
2032 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2033
2034 if (TraceExceptions) {
2035 ResourceMark rm;
2036 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2037 if (has_last_Java_frame()) {
2038 frame f = last_frame();
2039 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2040 }
2041 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2042 }
2043 _pending_async_exception = NULL;
2044 clear_has_async_exception();
2045 }
2046 }
2047
2048 if (check_unsafe_error &&
2049 condition == _async_unsafe_access_error && !has_pending_exception()) {
2050 condition = _no_async_condition; // done
2051 switch (thread_state()) {
2052 case _thread_in_vm: {
2053 JavaThread* THREAD = this;
2054 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2055 }
2056 case _thread_in_native: {
2057 ThreadInVMfromNative tiv(this);
2058 JavaThread* THREAD = this;
2059 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2060 }
2061 case _thread_in_Java: {
2062 ThreadInVMfromJava tiv(this);
2063 JavaThread* THREAD = this;
2064 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2065 }
2066 default:
2067 ShouldNotReachHere();
2068 }
2069 }
2070
2071 assert(condition == _no_async_condition || has_pending_exception() ||
2072 (!check_unsafe_error && condition == _async_unsafe_access_error),
2073 "must have handled the async condition, if no exception");
2074 }
2075
2076 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2077 //
2078 // Check for pending external suspend. Internal suspend requests do
2079 // not use handle_special_runtime_exit_condition().
2080 // If JNIEnv proxies are allowed, don't self-suspend if the target
2081 // thread is not the current thread. In older versions of jdbx, jdbx
2082 // threads could call into the VM with another thread's JNIEnv so we
2083 // can be here operating on behalf of a suspended thread (4432884).
2084 bool do_self_suspend = is_external_suspend_with_lock();
2085 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2086 //
2087 // Because thread is external suspended the safepoint code will count
2088 // thread as at a safepoint. This can be odd because we can be here
2089 // as _thread_in_Java which would normally transition to _thread_blocked
2090 // at a safepoint. We would like to mark the thread as _thread_blocked
2091 // before calling java_suspend_self like all other callers of it but
2092 // we must then observe proper safepoint protocol. (We can't leave
2093 // _thread_blocked with a safepoint in progress). However we can be
2094 // here as _thread_in_native_trans so we can't use a normal transition
2095 // constructor/destructor pair because they assert on that type of
2096 // transition. We could do something like:
2097 //
2098 // JavaThreadState state = thread_state();
2099 // set_thread_state(_thread_in_vm);
2100 // {
2101 // ThreadBlockInVM tbivm(this);
2102 // java_suspend_self()
2103 // }
2104 // set_thread_state(_thread_in_vm_trans);
2105 // if (safepoint) block;
2106 // set_thread_state(state);
2107 //
2108 // but that is pretty messy. Instead we just go with the way the
2109 // code has worked before and note that this is the only path to
2110 // java_suspend_self that doesn't put the thread in _thread_blocked
2111 // mode.
2112
2113 frame_anchor()->make_walkable(this);
2114 java_suspend_self();
2115
2116 // We might be here for reasons in addition to the self-suspend request
2117 // so check for other async requests.
2118 }
2119
2120 if (check_asyncs) {
2121 check_and_handle_async_exceptions();
2122 }
2123 }
2124
2125 void JavaThread::send_thread_stop(oop java_throwable) {
2126 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2127 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2128 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2129
2130 // Do not throw asynchronous exceptions against the compiler thread
2131 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2132 if (is_Compiler_thread()) return;
2133
2134 {
2135 // Actually throw the Throwable against the target Thread - however
2136 // only if there is no thread death exception installed already.
2137 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2138 // If the topmost frame is a runtime stub, then we are calling into
2139 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2140 // must deoptimize the caller before continuing, as the compiled exception handler table
2141 // may not be valid
2142 if (has_last_Java_frame()) {
2143 frame f = last_frame();
2144 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2145 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2146 RegisterMap reg_map(this, UseBiasedLocking);
2147 frame compiled_frame = f.sender(®_map);
2148 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2149 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2150 }
2151 }
2152 }
2153
2154 // Set async. pending exception in thread.
2155 set_pending_async_exception(java_throwable);
2156
2157 if (TraceExceptions) {
2158 ResourceMark rm;
2159 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2160 }
2161 // for AbortVMOnException flag
2162 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2163 }
2164 }
2165
2166
2167 // Interrupt thread so it will wake up from a potential wait()
2168 Thread::interrupt(this);
2169 }
2170
2171 // External suspension mechanism.
2172 //
2173 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2174 // to any VM_locks and it is at a transition
2175 // Self-suspension will happen on the transition out of the vm.
2176 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2177 //
2178 // Guarantees on return:
2179 // + Target thread will not execute any new bytecode (that's why we need to
2180 // force a safepoint)
2181 // + Target thread will not enter any new monitors
2182 //
2183 void JavaThread::java_suspend() {
2184 { MutexLocker mu(Threads_lock);
2185 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2186 return;
2187 }
2188 }
2189
2190 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2191 if (!is_external_suspend()) {
2192 // a racing resume has cancelled us; bail out now
2193 return;
2194 }
2195
2196 // suspend is done
2197 uint32_t debug_bits = 0;
2198 // Warning: is_ext_suspend_completed() may temporarily drop the
2199 // SR_lock to allow the thread to reach a stable thread state if
2200 // it is currently in a transient thread state.
2201 if (is_ext_suspend_completed(false /* !called_by_wait */,
2202 SuspendRetryDelay, &debug_bits)) {
2203 return;
2204 }
2205 }
2206
2207 VM_ForceSafepoint vm_suspend;
2208 VMThread::execute(&vm_suspend);
2209 }
2210
2211 // Part II of external suspension.
2212 // A JavaThread self suspends when it detects a pending external suspend
2213 // request. This is usually on transitions. It is also done in places
2214 // where continuing to the next transition would surprise the caller,
2215 // e.g., monitor entry.
2216 //
2217 // Returns the number of times that the thread self-suspended.
2218 //
2219 // Note: DO NOT call java_suspend_self() when you just want to block current
2220 // thread. java_suspend_self() is the second stage of cooperative
2221 // suspension for external suspend requests and should only be used
2222 // to complete an external suspend request.
2223 //
2224 int JavaThread::java_suspend_self() {
2225 int ret = 0;
2226
2227 // we are in the process of exiting so don't suspend
2228 if (is_exiting()) {
2229 clear_external_suspend();
2230 return ret;
2231 }
2232
2233 assert(_anchor.walkable() ||
2234 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2235 "must have walkable stack");
2236
2237 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2238
2239 assert(!this->is_ext_suspended(),
2240 "a thread trying to self-suspend should not already be suspended");
2241
2242 if (this->is_suspend_equivalent()) {
2243 // If we are self-suspending as a result of the lifting of a
2244 // suspend equivalent condition, then the suspend_equivalent
2245 // flag is not cleared until we set the ext_suspended flag so
2246 // that wait_for_ext_suspend_completion() returns consistent
2247 // results.
2248 this->clear_suspend_equivalent();
2249 }
2250
2251 // A racing resume may have cancelled us before we grabbed SR_lock
2252 // above. Or another external suspend request could be waiting for us
2253 // by the time we return from SR_lock()->wait(). The thread
2254 // that requested the suspension may already be trying to walk our
2255 // stack and if we return now, we can change the stack out from under
2256 // it. This would be a "bad thing (TM)" and cause the stack walker
2257 // to crash. We stay self-suspended until there are no more pending
2258 // external suspend requests.
2259 while (is_external_suspend()) {
2260 ret++;
2261 this->set_ext_suspended();
2262
2263 // _ext_suspended flag is cleared by java_resume()
2264 while (is_ext_suspended()) {
2265 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2266 }
2267 }
2268
2269 return ret;
2270 }
2271
2272 #ifdef ASSERT
2273 // verify the JavaThread has not yet been published in the Threads::list, and
2274 // hence doesn't need protection from concurrent access at this stage
2275 void JavaThread::verify_not_published() {
2276 if (!Threads_lock->owned_by_self()) {
2277 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2278 assert(!Threads::includes(this),
2279 "java thread shouldn't have been published yet!");
2280 } else {
2281 assert(!Threads::includes(this),
2282 "java thread shouldn't have been published yet!");
2283 }
2284 }
2285 #endif
2286
2287 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2288 // progress or when _suspend_flags is non-zero.
2289 // Current thread needs to self-suspend if there is a suspend request and/or
2290 // block if a safepoint is in progress.
2291 // Async exception ISN'T checked.
2292 // Note only the ThreadInVMfromNative transition can call this function
2293 // directly and when thread state is _thread_in_native_trans
2294 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2295 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2296
2297 JavaThread *curJT = JavaThread::current();
2298 bool do_self_suspend = thread->is_external_suspend();
2299
2300 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2301
2302 // If JNIEnv proxies are allowed, don't self-suspend if the target
2303 // thread is not the current thread. In older versions of jdbx, jdbx
2304 // threads could call into the VM with another thread's JNIEnv so we
2305 // can be here operating on behalf of a suspended thread (4432884).
2306 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2307 JavaThreadState state = thread->thread_state();
2308
2309 // We mark this thread_blocked state as a suspend-equivalent so
2310 // that a caller to is_ext_suspend_completed() won't be confused.
2311 // The suspend-equivalent state is cleared by java_suspend_self().
2312 thread->set_suspend_equivalent();
2313
2314 // If the safepoint code sees the _thread_in_native_trans state, it will
2315 // wait until the thread changes to other thread state. There is no
2316 // guarantee on how soon we can obtain the SR_lock and complete the
2317 // self-suspend request. It would be a bad idea to let safepoint wait for
2318 // too long. Temporarily change the state to _thread_blocked to
2319 // let the VM thread know that this thread is ready for GC. The problem
2320 // of changing thread state is that safepoint could happen just after
2321 // java_suspend_self() returns after being resumed, and VM thread will
2322 // see the _thread_blocked state. We must check for safepoint
2323 // after restoring the state and make sure we won't leave while a safepoint
2324 // is in progress.
2325 thread->set_thread_state(_thread_blocked);
2326 thread->java_suspend_self();
2327 thread->set_thread_state(state);
2328 // Make sure new state is seen by VM thread
2329 if (os::is_MP()) {
2330 if (UseMembar) {
2331 // Force a fence between the write above and read below
2332 OrderAccess::fence();
2333 } else {
2334 // Must use this rather than serialization page in particular on Windows
2335 InterfaceSupport::serialize_memory(thread);
2336 }
2337 }
2338 }
2339
2340 if (SafepointSynchronize::do_call_back()) {
2341 // If we are safepointing, then block the caller which may not be
2342 // the same as the target thread (see above).
2343 SafepointSynchronize::block(curJT);
2344 }
2345
2346 if (thread->is_deopt_suspend()) {
2347 thread->clear_deopt_suspend();
2348 RegisterMap map(thread, false);
2349 frame f = thread->last_frame();
2350 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2351 f = f.sender(&map);
2352 }
2353 if (f.id() == thread->must_deopt_id()) {
2354 thread->clear_must_deopt_id();
2355 f.deoptimize(thread);
2356 } else {
2357 fatal("missed deoptimization!");
2358 }
2359 }
2360 }
2361
2362 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2363 // progress or when _suspend_flags is non-zero.
2364 // Current thread needs to self-suspend if there is a suspend request and/or
2365 // block if a safepoint is in progress.
2366 // Also check for pending async exception (not including unsafe access error).
2367 // Note only the native==>VM/Java barriers can call this function and when
2368 // thread state is _thread_in_native_trans.
2369 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2370 check_safepoint_and_suspend_for_native_trans(thread);
2371
2372 if (thread->has_async_exception()) {
2373 // We are in _thread_in_native_trans state, don't handle unsafe
2374 // access error since that may block.
2375 thread->check_and_handle_async_exceptions(false);
2376 }
2377 }
2378
2379 // This is a variant of the normal
2380 // check_special_condition_for_native_trans with slightly different
2381 // semantics for use by critical native wrappers. It does all the
2382 // normal checks but also performs the transition back into
2383 // thread_in_Java state. This is required so that critical natives
2384 // can potentially block and perform a GC if they are the last thread
2385 // exiting the GC_locker.
2386 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2387 check_special_condition_for_native_trans(thread);
2388
2389 // Finish the transition
2390 thread->set_thread_state(_thread_in_Java);
2391
2392 if (thread->do_critical_native_unlock()) {
2393 ThreadInVMfromJavaNoAsyncException tiv(thread);
2394 GC_locker::unlock_critical(thread);
2395 thread->clear_critical_native_unlock();
2396 }
2397 }
2398
2399 // We need to guarantee the Threads_lock here, since resumes are not
2400 // allowed during safepoint synchronization
2401 // Can only resume from an external suspension
2402 void JavaThread::java_resume() {
2403 assert_locked_or_safepoint(Threads_lock);
2404
2405 // Sanity check: thread is gone, has started exiting or the thread
2406 // was not externally suspended.
2407 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2408 return;
2409 }
2410
2411 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2412
2413 clear_external_suspend();
2414
2415 if (is_ext_suspended()) {
2416 clear_ext_suspended();
2417 SR_lock()->notify_all();
2418 }
2419 }
2420
2421 void JavaThread::create_stack_guard_pages() {
2422 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2423 address low_addr = stack_base() - stack_size();
2424 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2425
2426 int allocate = os::allocate_stack_guard_pages();
2427 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2428
2429 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2430 warning("Attempt to allocate stack guard pages failed.");
2431 return;
2432 }
2433
2434 if (os::guard_memory((char *) low_addr, len)) {
2435 _stack_guard_state = stack_guard_enabled;
2436 } else {
2437 warning("Attempt to protect stack guard pages failed.");
2438 if (os::uncommit_memory((char *) low_addr, len)) {
2439 warning("Attempt to deallocate stack guard pages failed.");
2440 }
2441 }
2442 }
2443
2444 void JavaThread::remove_stack_guard_pages() {
2445 assert(Thread::current() == this, "from different thread");
2446 if (_stack_guard_state == stack_guard_unused) return;
2447 address low_addr = stack_base() - stack_size();
2448 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2449
2450 if (os::allocate_stack_guard_pages()) {
2451 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2452 _stack_guard_state = stack_guard_unused;
2453 } else {
2454 warning("Attempt to deallocate stack guard pages failed.");
2455 }
2456 } else {
2457 if (_stack_guard_state == stack_guard_unused) return;
2458 if (os::unguard_memory((char *) low_addr, len)) {
2459 _stack_guard_state = stack_guard_unused;
2460 } else {
2461 warning("Attempt to unprotect stack guard pages failed.");
2462 }
2463 }
2464 }
2465
2466 void JavaThread::enable_stack_yellow_zone() {
2467 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2468 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2469
2470 // The base notation is from the stacks point of view, growing downward.
2471 // We need to adjust it to work correctly with guard_memory()
2472 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2473
2474 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2475 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2476
2477 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2478 _stack_guard_state = stack_guard_enabled;
2479 } else {
2480 warning("Attempt to guard stack yellow zone failed.");
2481 }
2482 enable_register_stack_guard();
2483 }
2484
2485 void JavaThread::disable_stack_yellow_zone() {
2486 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2487 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2488
2489 // Simply return if called for a thread that does not use guard pages.
2490 if (_stack_guard_state == stack_guard_unused) return;
2491
2492 // The base notation is from the stacks point of view, growing downward.
2493 // We need to adjust it to work correctly with guard_memory()
2494 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2495
2496 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2497 _stack_guard_state = stack_guard_yellow_disabled;
2498 } else {
2499 warning("Attempt to unguard stack yellow zone failed.");
2500 }
2501 disable_register_stack_guard();
2502 }
2503
2504 void JavaThread::enable_stack_red_zone() {
2505 // The base notation is from the stacks point of view, growing downward.
2506 // We need to adjust it to work correctly with guard_memory()
2507 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2508 address base = stack_red_zone_base() - stack_red_zone_size();
2509
2510 guarantee(base < stack_base(), "Error calculating stack red zone");
2511 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2512
2513 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2514 warning("Attempt to guard stack red zone failed.");
2515 }
2516 }
2517
2518 void JavaThread::disable_stack_red_zone() {
2519 // The base notation is from the stacks point of view, growing downward.
2520 // We need to adjust it to work correctly with guard_memory()
2521 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2522 address base = stack_red_zone_base() - stack_red_zone_size();
2523 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2524 warning("Attempt to unguard stack red zone failed.");
2525 }
2526 }
2527
2528 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2529 // ignore is there is no stack
2530 if (!has_last_Java_frame()) return;
2531 // traverse the stack frames. Starts from top frame.
2532 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2533 frame* fr = fst.current();
2534 f(fr, fst.register_map());
2535 }
2536 }
2537
2538
2539 #ifndef PRODUCT
2540 // Deoptimization
2541 // Function for testing deoptimization
2542 void JavaThread::deoptimize() {
2543 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2544 StackFrameStream fst(this, UseBiasedLocking);
2545 bool deopt = false; // Dump stack only if a deopt actually happens.
2546 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2547 // Iterate over all frames in the thread and deoptimize
2548 for (; !fst.is_done(); fst.next()) {
2549 if (fst.current()->can_be_deoptimized()) {
2550
2551 if (only_at) {
2552 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2553 // consists of comma or carriage return separated numbers so
2554 // search for the current bci in that string.
2555 address pc = fst.current()->pc();
2556 nmethod* nm = (nmethod*) fst.current()->cb();
2557 ScopeDesc* sd = nm->scope_desc_at(pc);
2558 char buffer[8];
2559 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2560 size_t len = strlen(buffer);
2561 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2562 while (found != NULL) {
2563 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2564 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2565 // Check that the bci found is bracketed by terminators.
2566 break;
2567 }
2568 found = strstr(found + 1, buffer);
2569 }
2570 if (!found) {
2571 continue;
2572 }
2573 }
2574
2575 if (DebugDeoptimization && !deopt) {
2576 deopt = true; // One-time only print before deopt
2577 tty->print_cr("[BEFORE Deoptimization]");
2578 trace_frames();
2579 trace_stack();
2580 }
2581 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2582 }
2583 }
2584
2585 if (DebugDeoptimization && deopt) {
2586 tty->print_cr("[AFTER Deoptimization]");
2587 trace_frames();
2588 }
2589 }
2590
2591
2592 // Make zombies
2593 void JavaThread::make_zombies() {
2594 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2595 if (fst.current()->can_be_deoptimized()) {
2596 // it is a Java nmethod
2597 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2598 nm->make_not_entrant();
2599 }
2600 }
2601 }
2602 #endif // PRODUCT
2603
2604
2605 void JavaThread::deoptimized_wrt_marked_nmethods() {
2606 if (!has_last_Java_frame()) return;
2607 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2608 StackFrameStream fst(this, UseBiasedLocking);
2609 for (; !fst.is_done(); fst.next()) {
2610 if (fst.current()->should_be_deoptimized()) {
2611 if (LogCompilation && xtty != NULL) {
2612 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2613 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2614 this->name(), nm != NULL ? nm->compile_id() : -1);
2615 }
2616
2617 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2618 }
2619 }
2620 }
2621
2622
2623 // If the caller is a NamedThread, then remember, in the current scope,
2624 // the given JavaThread in its _processed_thread field.
2625 class RememberProcessedThread: public StackObj {
2626 NamedThread* _cur_thr;
2627 public:
2628 RememberProcessedThread(JavaThread* jthr) {
2629 Thread* thread = Thread::current();
2630 if (thread->is_Named_thread()) {
2631 _cur_thr = (NamedThread *)thread;
2632 _cur_thr->set_processed_thread(jthr);
2633 } else {
2634 _cur_thr = NULL;
2635 }
2636 }
2637
2638 ~RememberProcessedThread() {
2639 if (_cur_thr) {
2640 _cur_thr->set_processed_thread(NULL);
2641 }
2642 }
2643 };
2644
2645 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2646 // Verify that the deferred card marks have been flushed.
2647 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2648
2649 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2650 // since there may be more than one thread using each ThreadProfiler.
2651
2652 // Traverse the GCHandles
2653 Thread::oops_do(f, cld_f, cf);
2654
2655 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2656 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2657
2658 if (has_last_Java_frame()) {
2659 // Record JavaThread to GC thread
2660 RememberProcessedThread rpt(this);
2661
2662 // Traverse the privileged stack
2663 if (_privileged_stack_top != NULL) {
2664 _privileged_stack_top->oops_do(f);
2665 }
2666
2667 // traverse the registered growable array
2668 if (_array_for_gc != NULL) {
2669 for (int index = 0; index < _array_for_gc->length(); index++) {
2670 f->do_oop(_array_for_gc->adr_at(index));
2671 }
2672 }
2673
2674 // Traverse the monitor chunks
2675 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2676 chunk->oops_do(f);
2677 }
2678
2679 // Traverse the execution stack
2680 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2681 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2682 }
2683 }
2684
2685 // callee_target is never live across a gc point so NULL it here should
2686 // it still contain a methdOop.
2687
2688 set_callee_target(NULL);
2689
2690 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2691 // If we have deferred set_locals there might be oops waiting to be
2692 // written
2693 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2694 if (list != NULL) {
2695 for (int i = 0; i < list->length(); i++) {
2696 list->at(i)->oops_do(f);
2697 }
2698 }
2699
2700 // Traverse instance variables at the end since the GC may be moving things
2701 // around using this function
2702 f->do_oop((oop*) &_threadObj);
2703 f->do_oop((oop*) &_vm_result);
2704 f->do_oop((oop*) &_exception_oop);
2705 f->do_oop((oop*) &_pending_async_exception);
2706
2707 if (jvmti_thread_state() != NULL) {
2708 jvmti_thread_state()->oops_do(f);
2709 }
2710 }
2711
2712 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2713 Thread::nmethods_do(cf); // (super method is a no-op)
2714
2715 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2716 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2717
2718 if (has_last_Java_frame()) {
2719 // Traverse the execution stack
2720 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2721 fst.current()->nmethods_do(cf);
2722 }
2723 }
2724 }
2725
2726 void JavaThread::metadata_do(void f(Metadata*)) {
2727 if (has_last_Java_frame()) {
2728 // Traverse the execution stack to call f() on the methods in the stack
2729 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2730 fst.current()->metadata_do(f);
2731 }
2732 } else if (is_Compiler_thread()) {
2733 // need to walk ciMetadata in current compile tasks to keep alive.
2734 CompilerThread* ct = (CompilerThread*)this;
2735 if (ct->env() != NULL) {
2736 ct->env()->metadata_do(f);
2737 }
2738 }
2739 }
2740
2741 // Printing
2742 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2743 switch (_thread_state) {
2744 case _thread_uninitialized: return "_thread_uninitialized";
2745 case _thread_new: return "_thread_new";
2746 case _thread_new_trans: return "_thread_new_trans";
2747 case _thread_in_native: return "_thread_in_native";
2748 case _thread_in_native_trans: return "_thread_in_native_trans";
2749 case _thread_in_vm: return "_thread_in_vm";
2750 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2751 case _thread_in_Java: return "_thread_in_Java";
2752 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2753 case _thread_blocked: return "_thread_blocked";
2754 case _thread_blocked_trans: return "_thread_blocked_trans";
2755 default: return "unknown thread state";
2756 }
2757 }
2758
2759 #ifndef PRODUCT
2760 void JavaThread::print_thread_state_on(outputStream *st) const {
2761 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2762 };
2763 void JavaThread::print_thread_state() const {
2764 print_thread_state_on(tty);
2765 }
2766 #endif // PRODUCT
2767
2768 // Called by Threads::print() for VM_PrintThreads operation
2769 void JavaThread::print_on(outputStream *st) const {
2770 st->print("\"%s\" ", get_thread_name());
2771 oop thread_oop = threadObj();
2772 if (thread_oop != NULL) {
2773 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2774 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2775 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2776 }
2777 Thread::print_on(st);
2778 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2779 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2780 if (thread_oop != NULL) {
2781 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2782 }
2783 #ifndef PRODUCT
2784 print_thread_state_on(st);
2785 _safepoint_state->print_on(st);
2786 #endif // PRODUCT
2787 }
2788
2789 // Called by fatal error handler. The difference between this and
2790 // JavaThread::print() is that we can't grab lock or allocate memory.
2791 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2792 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2793 oop thread_obj = threadObj();
2794 if (thread_obj != NULL) {
2795 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2796 }
2797 st->print(" [");
2798 st->print("%s", _get_thread_state_name(_thread_state));
2799 if (osthread()) {
2800 st->print(", id=%d", osthread()->thread_id());
2801 }
2802 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2803 _stack_base - _stack_size, _stack_base);
2804 st->print("]");
2805 return;
2806 }
2807
2808 // Verification
2809
2810 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2811
2812 void JavaThread::verify() {
2813 // Verify oops in the thread.
2814 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2815
2816 // Verify the stack frames.
2817 frames_do(frame_verify);
2818 }
2819
2820 // CR 6300358 (sub-CR 2137150)
2821 // Most callers of this method assume that it can't return NULL but a
2822 // thread may not have a name whilst it is in the process of attaching to
2823 // the VM - see CR 6412693, and there are places where a JavaThread can be
2824 // seen prior to having it's threadObj set (eg JNI attaching threads and
2825 // if vm exit occurs during initialization). These cases can all be accounted
2826 // for such that this method never returns NULL.
2827 const char* JavaThread::get_thread_name() const {
2828 #ifdef ASSERT
2829 // early safepoints can hit while current thread does not yet have TLS
2830 if (!SafepointSynchronize::is_at_safepoint()) {
2831 Thread *cur = Thread::current();
2832 if (!(cur->is_Java_thread() && cur == this)) {
2833 // Current JavaThreads are allowed to get their own name without
2834 // the Threads_lock.
2835 assert_locked_or_safepoint(Threads_lock);
2836 }
2837 }
2838 #endif // ASSERT
2839 return get_thread_name_string();
2840 }
2841
2842 // Returns a non-NULL representation of this thread's name, or a suitable
2843 // descriptive string if there is no set name
2844 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2845 const char* name_str;
2846 oop thread_obj = threadObj();
2847 if (thread_obj != NULL) {
2848 oop name = java_lang_Thread::name(thread_obj);
2849 if (name != NULL) {
2850 if (buf == NULL) {
2851 name_str = java_lang_String::as_utf8_string(name);
2852 } else {
2853 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2854 }
2855 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2856 name_str = "<no-name - thread is attaching>";
2857 } else {
2858 name_str = Thread::name();
2859 }
2860 } else {
2861 name_str = Thread::name();
2862 }
2863 assert(name_str != NULL, "unexpected NULL thread name");
2864 return name_str;
2865 }
2866
2867
2868 const char* JavaThread::get_threadgroup_name() const {
2869 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2870 oop thread_obj = threadObj();
2871 if (thread_obj != NULL) {
2872 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2873 if (thread_group != NULL) {
2874 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2875 // ThreadGroup.name can be null
2876 if (name != NULL) {
2877 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2878 return str;
2879 }
2880 }
2881 }
2882 return NULL;
2883 }
2884
2885 const char* JavaThread::get_parent_name() const {
2886 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2887 oop thread_obj = threadObj();
2888 if (thread_obj != NULL) {
2889 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2890 if (thread_group != NULL) {
2891 oop parent = java_lang_ThreadGroup::parent(thread_group);
2892 if (parent != NULL) {
2893 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2894 // ThreadGroup.name can be null
2895 if (name != NULL) {
2896 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2897 return str;
2898 }
2899 }
2900 }
2901 }
2902 return NULL;
2903 }
2904
2905 ThreadPriority JavaThread::java_priority() const {
2906 oop thr_oop = threadObj();
2907 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2908 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2909 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2910 return priority;
2911 }
2912
2913 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2914
2915 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2916 // Link Java Thread object <-> C++ Thread
2917
2918 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2919 // and put it into a new Handle. The Handle "thread_oop" can then
2920 // be used to pass the C++ thread object to other methods.
2921
2922 // Set the Java level thread object (jthread) field of the
2923 // new thread (a JavaThread *) to C++ thread object using the
2924 // "thread_oop" handle.
2925
2926 // Set the thread field (a JavaThread *) of the
2927 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2928
2929 Handle thread_oop(Thread::current(),
2930 JNIHandles::resolve_non_null(jni_thread));
2931 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2932 "must be initialized");
2933 set_threadObj(thread_oop());
2934 java_lang_Thread::set_thread(thread_oop(), this);
2935
2936 if (prio == NoPriority) {
2937 prio = java_lang_Thread::priority(thread_oop());
2938 assert(prio != NoPriority, "A valid priority should be present");
2939 }
2940
2941 // Push the Java priority down to the native thread; needs Threads_lock
2942 Thread::set_priority(this, prio);
2943
2944 prepare_ext();
2945
2946 // Add the new thread to the Threads list and set it in motion.
2947 // We must have threads lock in order to call Threads::add.
2948 // It is crucial that we do not block before the thread is
2949 // added to the Threads list for if a GC happens, then the java_thread oop
2950 // will not be visited by GC.
2951 Threads::add(this);
2952 }
2953
2954 oop JavaThread::current_park_blocker() {
2955 // Support for JSR-166 locks
2956 oop thread_oop = threadObj();
2957 if (thread_oop != NULL &&
2958 JDK_Version::current().supports_thread_park_blocker()) {
2959 return java_lang_Thread::park_blocker(thread_oop);
2960 }
2961 return NULL;
2962 }
2963
2964
2965 void JavaThread::print_stack_on(outputStream* st) {
2966 if (!has_last_Java_frame()) return;
2967 ResourceMark rm;
2968 HandleMark hm;
2969
2970 RegisterMap reg_map(this);
2971 vframe* start_vf = last_java_vframe(®_map);
2972 int count = 0;
2973 for (vframe* f = start_vf; f; f = f->sender()) {
2974 if (f->is_java_frame()) {
2975 javaVFrame* jvf = javaVFrame::cast(f);
2976 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2977
2978 // Print out lock information
2979 if (JavaMonitorsInStackTrace) {
2980 jvf->print_lock_info_on(st, count);
2981 }
2982 } else {
2983 // Ignore non-Java frames
2984 }
2985
2986 // Bail-out case for too deep stacks
2987 count++;
2988 if (MaxJavaStackTraceDepth == count) return;
2989 }
2990 }
2991
2992
2993 // JVMTI PopFrame support
2994 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2995 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2996 if (in_bytes(size_in_bytes) != 0) {
2997 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
2998 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2999 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3000 }
3001 }
3002
3003 void* JavaThread::popframe_preserved_args() {
3004 return _popframe_preserved_args;
3005 }
3006
3007 ByteSize JavaThread::popframe_preserved_args_size() {
3008 return in_ByteSize(_popframe_preserved_args_size);
3009 }
3010
3011 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3012 int sz = in_bytes(popframe_preserved_args_size());
3013 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3014 return in_WordSize(sz / wordSize);
3015 }
3016
3017 void JavaThread::popframe_free_preserved_args() {
3018 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3019 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3020 _popframe_preserved_args = NULL;
3021 _popframe_preserved_args_size = 0;
3022 }
3023
3024 #ifndef PRODUCT
3025
3026 void JavaThread::trace_frames() {
3027 tty->print_cr("[Describe stack]");
3028 int frame_no = 1;
3029 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3030 tty->print(" %d. ", frame_no++);
3031 fst.current()->print_value_on(tty, this);
3032 tty->cr();
3033 }
3034 }
3035
3036 class PrintAndVerifyOopClosure: public OopClosure {
3037 protected:
3038 template <class T> inline void do_oop_work(T* p) {
3039 oop obj = oopDesc::load_decode_heap_oop(p);
3040 if (obj == NULL) return;
3041 tty->print(INTPTR_FORMAT ": ", p);
3042 if (obj->is_oop_or_null()) {
3043 if (obj->is_objArray()) {
3044 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3045 } else {
3046 obj->print();
3047 }
3048 } else {
3049 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3050 }
3051 tty->cr();
3052 }
3053 public:
3054 virtual void do_oop(oop* p) { do_oop_work(p); }
3055 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3056 };
3057
3058
3059 static void oops_print(frame* f, const RegisterMap *map) {
3060 PrintAndVerifyOopClosure print;
3061 f->print_value();
3062 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3063 }
3064
3065 // Print our all the locations that contain oops and whether they are
3066 // valid or not. This useful when trying to find the oldest frame
3067 // where an oop has gone bad since the frame walk is from youngest to
3068 // oldest.
3069 void JavaThread::trace_oops() {
3070 tty->print_cr("[Trace oops]");
3071 frames_do(oops_print);
3072 }
3073
3074
3075 #ifdef ASSERT
3076 // Print or validate the layout of stack frames
3077 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3078 ResourceMark rm;
3079 PRESERVE_EXCEPTION_MARK;
3080 FrameValues values;
3081 int frame_no = 0;
3082 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3083 fst.current()->describe(values, ++frame_no);
3084 if (depth == frame_no) break;
3085 }
3086 if (validate_only) {
3087 values.validate();
3088 } else {
3089 tty->print_cr("[Describe stack layout]");
3090 values.print(this);
3091 }
3092 }
3093 #endif
3094
3095 void JavaThread::trace_stack_from(vframe* start_vf) {
3096 ResourceMark rm;
3097 int vframe_no = 1;
3098 for (vframe* f = start_vf; f; f = f->sender()) {
3099 if (f->is_java_frame()) {
3100 javaVFrame::cast(f)->print_activation(vframe_no++);
3101 } else {
3102 f->print();
3103 }
3104 if (vframe_no > StackPrintLimit) {
3105 tty->print_cr("...<more frames>...");
3106 return;
3107 }
3108 }
3109 }
3110
3111
3112 void JavaThread::trace_stack() {
3113 if (!has_last_Java_frame()) return;
3114 ResourceMark rm;
3115 HandleMark hm;
3116 RegisterMap reg_map(this);
3117 trace_stack_from(last_java_vframe(®_map));
3118 }
3119
3120
3121 #endif // PRODUCT
3122
3123
3124 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3125 assert(reg_map != NULL, "a map must be given");
3126 frame f = last_frame();
3127 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3128 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3129 }
3130 return NULL;
3131 }
3132
3133
3134 Klass* JavaThread::security_get_caller_class(int depth) {
3135 vframeStream vfst(this);
3136 vfst.security_get_caller_frame(depth);
3137 if (!vfst.at_end()) {
3138 return vfst.method()->method_holder();
3139 }
3140 return NULL;
3141 }
3142
3143 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3144 assert(thread->is_Compiler_thread(), "must be compiler thread");
3145 CompileBroker::compiler_thread_loop();
3146 }
3147
3148 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3149 NMethodSweeper::sweeper_loop();
3150 }
3151
3152 // Create a CompilerThread
3153 CompilerThread::CompilerThread(CompileQueue* queue,
3154 CompilerCounters* counters)
3155 : JavaThread(&compiler_thread_entry) {
3156 _env = NULL;
3157 _log = NULL;
3158 _task = NULL;
3159 _queue = queue;
3160 _counters = counters;
3161 _buffer_blob = NULL;
3162 _compiler = NULL;
3163
3164 #ifndef PRODUCT
3165 _ideal_graph_printer = NULL;
3166 #endif
3167 }
3168
3169 // Create sweeper thread
3170 CodeCacheSweeperThread::CodeCacheSweeperThread()
3171 : JavaThread(&sweeper_thread_entry) {
3172 _scanned_nmethod = NULL;
3173 }
3174 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3175 JavaThread::oops_do(f, cld_f, cf);
3176 if (_scanned_nmethod != NULL && cf != NULL) {
3177 // Safepoints can occur when the sweeper is scanning an nmethod so
3178 // process it here to make sure it isn't unloaded in the middle of
3179 // a scan.
3180 cf->do_code_blob(_scanned_nmethod);
3181 }
3182 }
3183
3184
3185 // ======= Threads ========
3186
3187 // The Threads class links together all active threads, and provides
3188 // operations over all threads. It is protected by its own Mutex
3189 // lock, which is also used in other contexts to protect thread
3190 // operations from having the thread being operated on from exiting
3191 // and going away unexpectedly (e.g., safepoint synchronization)
3192
3193 JavaThread* Threads::_thread_list = NULL;
3194 int Threads::_number_of_threads = 0;
3195 int Threads::_number_of_non_daemon_threads = 0;
3196 int Threads::_return_code = 0;
3197 int Threads::_thread_claim_parity = 0;
3198 size_t JavaThread::_stack_size_at_create = 0;
3199 #ifdef ASSERT
3200 bool Threads::_vm_complete = false;
3201 #endif
3202
3203 // All JavaThreads
3204 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3205
3206 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3207 void Threads::threads_do(ThreadClosure* tc) {
3208 assert_locked_or_safepoint(Threads_lock);
3209 // ALL_JAVA_THREADS iterates through all JavaThreads
3210 ALL_JAVA_THREADS(p) {
3211 tc->do_thread(p);
3212 }
3213 // Someday we could have a table or list of all non-JavaThreads.
3214 // For now, just manually iterate through them.
3215 tc->do_thread(VMThread::vm_thread());
3216 Universe::heap()->gc_threads_do(tc);
3217 WatcherThread *wt = WatcherThread::watcher_thread();
3218 // Strictly speaking, the following NULL check isn't sufficient to make sure
3219 // the data for WatcherThread is still valid upon being examined. However,
3220 // considering that WatchThread terminates when the VM is on the way to
3221 // exit at safepoint, the chance of the above is extremely small. The right
3222 // way to prevent termination of WatcherThread would be to acquire
3223 // Terminator_lock, but we can't do that without violating the lock rank
3224 // checking in some cases.
3225 if (wt != NULL) {
3226 tc->do_thread(wt);
3227 }
3228
3229 // If CompilerThreads ever become non-JavaThreads, add them here
3230 }
3231
3232 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3233 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3234
3235 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3236 create_vm_init_libraries();
3237 }
3238
3239 initialize_class(vmSymbols::java_lang_String(), CHECK);
3240
3241 // Initialize java_lang.System (needed before creating the thread)
3242 initialize_class(vmSymbols::java_lang_System(), CHECK);
3243 // The VM creates & returns objects of this class. Make sure it's initialized.
3244 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3245 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3246 Handle thread_group = create_initial_thread_group(CHECK);
3247 Universe::set_main_thread_group(thread_group());
3248 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3249 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3250 main_thread->set_threadObj(thread_object);
3251 // Set thread status to running since main thread has
3252 // been started and running.
3253 java_lang_Thread::set_thread_status(thread_object,
3254 java_lang_Thread::RUNNABLE);
3255
3256 // The VM preresolves methods to these classes. Make sure that they get initialized
3257 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3258 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3259 call_initializeSystemClass(CHECK);
3260
3261 // get the Java runtime name after java.lang.System is initialized
3262 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3263 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3264
3265 // an instance of OutOfMemory exception has been allocated earlier
3266 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3267 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3268 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3269 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3270 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3271 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3272 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3273 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3274 }
3275
3276 void Threads::initialize_jsr292_core_classes(TRAPS) {
3277 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3278 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3279 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3280 }
3281
3282 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3283 extern void JDK_Version_init();
3284
3285 // Preinitialize version info.
3286 VM_Version::early_initialize();
3287
3288 // Check version
3289 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3290
3291 // Initialize the output stream module
3292 ostream_init();
3293
3294 // Process java launcher properties.
3295 Arguments::process_sun_java_launcher_properties(args);
3296
3297 // Initialize the os module before using TLS
3298 os::init();
3299
3300 // Initialize system properties.
3301 Arguments::init_system_properties();
3302
3303 // So that JDK version can be used as a discriminator when parsing arguments
3304 JDK_Version_init();
3305
3306 // Update/Initialize System properties after JDK version number is known
3307 Arguments::init_version_specific_system_properties();
3308
3309 // Parse arguments
3310 jint parse_result = Arguments::parse(args);
3311 if (parse_result != JNI_OK) return parse_result;
3312
3313 os::init_before_ergo();
3314
3315 jint ergo_result = Arguments::apply_ergo();
3316 if (ergo_result != JNI_OK) return ergo_result;
3317
3318 // Final check of all arguments after ergonomics which may change values.
3319 if (!CommandLineFlags::check_all_ranges_and_constraints()) {
3320 return JNI_EINVAL;
3321 }
3322
3323 if (PauseAtStartup) {
3324 os::pause();
3325 }
3326
3327 HOTSPOT_VM_INIT_BEGIN();
3328
3329 // Record VM creation timing statistics
3330 TraceVmCreationTime create_vm_timer;
3331 create_vm_timer.start();
3332
3333 // Timing (must come after argument parsing)
3334 TraceTime timer("Create VM", TraceStartupTime);
3335
3336 // Initialize the os module after parsing the args
3337 jint os_init_2_result = os::init_2();
3338 if (os_init_2_result != JNI_OK) return os_init_2_result;
3339
3340 jint adjust_after_os_result = Arguments::adjust_after_os();
3341 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3342
3343 // initialize TLS
3344 ThreadLocalStorage::init();
3345
3346 // Initialize output stream logging
3347 ostream_init_log();
3348
3349 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3350 // Must be before create_vm_init_agents()
3351 if (Arguments::init_libraries_at_startup()) {
3352 convert_vm_init_libraries_to_agents();
3353 }
3354
3355 // Launch -agentlib/-agentpath and converted -Xrun agents
3356 if (Arguments::init_agents_at_startup()) {
3357 create_vm_init_agents();
3358 }
3359
3360 // Initialize Threads state
3361 _thread_list = NULL;
3362 _number_of_threads = 0;
3363 _number_of_non_daemon_threads = 0;
3364
3365 // Initialize global data structures and create system classes in heap
3366 vm_init_globals();
3367
3368 // Attach the main thread to this os thread
3369 JavaThread* main_thread = new JavaThread();
3370 main_thread->set_thread_state(_thread_in_vm);
3371 // must do this before set_active_handles and initialize_thread_local_storage
3372 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3373 // change the stack size recorded here to one based on the java thread
3374 // stacksize. This adjusted size is what is used to figure the placement
3375 // of the guard pages.
3376 main_thread->record_stack_base_and_size();
3377 main_thread->initialize_thread_local_storage();
3378
3379 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3380
3381 if (!main_thread->set_as_starting_thread()) {
3382 vm_shutdown_during_initialization(
3383 "Failed necessary internal allocation. Out of swap space");
3384 delete main_thread;
3385 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3386 return JNI_ENOMEM;
3387 }
3388
3389 // Enable guard page *after* os::create_main_thread(), otherwise it would
3390 // crash Linux VM, see notes in os_linux.cpp.
3391 main_thread->create_stack_guard_pages();
3392
3393 // Initialize Java-Level synchronization subsystem
3394 ObjectMonitor::Initialize();
3395
3396 // Initialize global modules
3397 jint status = init_globals();
3398 if (status != JNI_OK) {
3399 delete main_thread;
3400 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3401 return status;
3402 }
3403
3404 // Should be done after the heap is fully created
3405 main_thread->cache_global_variables();
3406
3407 HandleMark hm;
3408
3409 { MutexLocker mu(Threads_lock);
3410 Threads::add(main_thread);
3411 }
3412
3413 // Any JVMTI raw monitors entered in onload will transition into
3414 // real raw monitor. VM is setup enough here for raw monitor enter.
3415 JvmtiExport::transition_pending_onload_raw_monitors();
3416
3417 // Create the VMThread
3418 { TraceTime timer("Start VMThread", TraceStartupTime);
3419 VMThread::create();
3420 Thread* vmthread = VMThread::vm_thread();
3421
3422 if (!os::create_thread(vmthread, os::vm_thread)) {
3423 vm_exit_during_initialization("Cannot create VM thread. "
3424 "Out of system resources.");
3425 }
3426
3427 // Wait for the VM thread to become ready, and VMThread::run to initialize
3428 // Monitors can have spurious returns, must always check another state flag
3429 {
3430 MutexLocker ml(Notify_lock);
3431 os::start_thread(vmthread);
3432 while (vmthread->active_handles() == NULL) {
3433 Notify_lock->wait();
3434 }
3435 }
3436 }
3437
3438 assert(Universe::is_fully_initialized(), "not initialized");
3439 if (VerifyDuringStartup) {
3440 // Make sure we're starting with a clean slate.
3441 VM_Verify verify_op;
3442 VMThread::execute(&verify_op);
3443 }
3444
3445 Thread* THREAD = Thread::current();
3446
3447 // At this point, the Universe is initialized, but we have not executed
3448 // any byte code. Now is a good time (the only time) to dump out the
3449 // internal state of the JVM for sharing.
3450 if (DumpSharedSpaces) {
3451 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3452 ShouldNotReachHere();
3453 }
3454
3455 // Always call even when there are not JVMTI environments yet, since environments
3456 // may be attached late and JVMTI must track phases of VM execution
3457 JvmtiExport::enter_start_phase();
3458
3459 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3460 JvmtiExport::post_vm_start();
3461
3462 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3463
3464 // We need this for ClassDataSharing - the initial vm.info property is set
3465 // with the default value of CDS "sharing" which may be reset through
3466 // command line options.
3467 reset_vm_info_property(CHECK_JNI_ERR);
3468
3469 quicken_jni_functions();
3470
3471 // Must be run after init_ft which initializes ft_enabled
3472 if (TRACE_INITIALIZE() != JNI_OK) {
3473 vm_exit_during_initialization("Failed to initialize tracing backend");
3474 }
3475
3476 // Set flag that basic initialization has completed. Used by exceptions and various
3477 // debug stuff, that does not work until all basic classes have been initialized.
3478 set_init_completed();
3479
3480 Metaspace::post_initialize();
3481
3482 HOTSPOT_VM_INIT_END();
3483
3484 // record VM initialization completion time
3485 #if INCLUDE_MANAGEMENT
3486 Management::record_vm_init_completed();
3487 #endif // INCLUDE_MANAGEMENT
3488
3489 // Compute system loader. Note that this has to occur after set_init_completed, since
3490 // valid exceptions may be thrown in the process.
3491 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3492 // set_init_completed has just been called, causing exceptions not to be shortcut
3493 // anymore. We call vm_exit_during_initialization directly instead.
3494 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3495
3496 #if INCLUDE_ALL_GCS
3497 // Support for ConcurrentMarkSweep. This should be cleaned up
3498 // and better encapsulated. The ugly nested if test would go away
3499 // once things are properly refactored. XXX YSR
3500 if (UseConcMarkSweepGC || UseG1GC) {
3501 if (UseConcMarkSweepGC) {
3502 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3503 } else {
3504 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3505 }
3506 }
3507 #endif // INCLUDE_ALL_GCS
3508
3509 // Always call even when there are not JVMTI environments yet, since environments
3510 // may be attached late and JVMTI must track phases of VM execution
3511 JvmtiExport::enter_live_phase();
3512
3513 // Signal Dispatcher needs to be started before VMInit event is posted
3514 os::signal_init();
3515
3516 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3517 if (!DisableAttachMechanism) {
3518 AttachListener::vm_start();
3519 if (StartAttachListener || AttachListener::init_at_startup()) {
3520 AttachListener::init();
3521 }
3522 }
3523
3524 // Launch -Xrun agents
3525 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3526 // back-end can launch with -Xdebug -Xrunjdwp.
3527 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3528 create_vm_init_libraries();
3529 }
3530
3531 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3532 JvmtiExport::post_vm_initialized();
3533
3534 if (TRACE_START() != JNI_OK) {
3535 vm_exit_during_initialization("Failed to start tracing backend.");
3536 }
3537
3538 if (CleanChunkPoolAsync) {
3539 Chunk::start_chunk_pool_cleaner_task();
3540 }
3541
3542 // initialize compiler(s)
3543 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3544 CompileBroker::compilation_init();
3545 #endif
3546
3547 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3548 // It is done after compilers are initialized, because otherwise compilations of
3549 // signature polymorphic MH intrinsics can be missed
3550 // (see SystemDictionary::find_method_handle_intrinsic).
3551 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3552
3553 #if INCLUDE_MANAGEMENT
3554 Management::initialize(THREAD);
3555
3556 if (HAS_PENDING_EXCEPTION) {
3557 // management agent fails to start possibly due to
3558 // configuration problem and is responsible for printing
3559 // stack trace if appropriate. Simply exit VM.
3560 vm_exit(1);
3561 }
3562 #endif // INCLUDE_MANAGEMENT
3563
3564 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3565 if (MemProfiling) MemProfiler::engage();
3566 StatSampler::engage();
3567 if (CheckJNICalls) JniPeriodicChecker::engage();
3568
3569 BiasedLocking::init();
3570
3571 #if INCLUDE_RTM_OPT
3572 RTMLockingCounters::init();
3573 #endif
3574
3575 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3576 call_postVMInitHook(THREAD);
3577 // The Java side of PostVMInitHook.run must deal with all
3578 // exceptions and provide means of diagnosis.
3579 if (HAS_PENDING_EXCEPTION) {
3580 CLEAR_PENDING_EXCEPTION;
3581 }
3582 }
3583
3584 {
3585 MutexLocker ml(PeriodicTask_lock);
3586 // Make sure the WatcherThread can be started by WatcherThread::start()
3587 // or by dynamic enrollment.
3588 WatcherThread::make_startable();
3589 // Start up the WatcherThread if there are any periodic tasks
3590 // NOTE: All PeriodicTasks should be registered by now. If they
3591 // aren't, late joiners might appear to start slowly (we might
3592 // take a while to process their first tick).
3593 if (PeriodicTask::num_tasks() > 0) {
3594 WatcherThread::start();
3595 }
3596 }
3597
3598 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3599
3600 create_vm_timer.end();
3601 #ifdef ASSERT
3602 _vm_complete = true;
3603 #endif
3604 return JNI_OK;
3605 }
3606
3607 // type for the Agent_OnLoad and JVM_OnLoad entry points
3608 extern "C" {
3609 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3610 }
3611 // Find a command line agent library and return its entry point for
3612 // -agentlib: -agentpath: -Xrun
3613 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3614 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3615 const char *on_load_symbols[],
3616 size_t num_symbol_entries) {
3617 OnLoadEntry_t on_load_entry = NULL;
3618 void *library = NULL;
3619
3620 if (!agent->valid()) {
3621 char buffer[JVM_MAXPATHLEN];
3622 char ebuf[1024] = "";
3623 const char *name = agent->name();
3624 const char *msg = "Could not find agent library ";
3625
3626 // First check to see if agent is statically linked into executable
3627 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3628 library = agent->os_lib();
3629 } else if (agent->is_absolute_path()) {
3630 library = os::dll_load(name, ebuf, sizeof ebuf);
3631 if (library == NULL) {
3632 const char *sub_msg = " in absolute 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 } else {
3641 // Try to load the agent from the standard dll directory
3642 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3643 name)) {
3644 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3645 }
3646 if (library == NULL) { // Try the local directory
3647 char ns[1] = {0};
3648 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3649 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3650 }
3651 if (library == NULL) {
3652 const char *sub_msg = " on the library path, with error: ";
3653 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3654 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3655 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3656 // If we can't find the agent, exit.
3657 vm_exit_during_initialization(buf, NULL);
3658 FREE_C_HEAP_ARRAY(char, buf);
3659 }
3660 }
3661 }
3662 agent->set_os_lib(library);
3663 agent->set_valid();
3664 }
3665
3666 // Find the OnLoad function.
3667 on_load_entry =
3668 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3669 false,
3670 on_load_symbols,
3671 num_symbol_entries));
3672 return on_load_entry;
3673 }
3674
3675 // Find the JVM_OnLoad entry point
3676 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3677 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3678 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3679 }
3680
3681 // Find the Agent_OnLoad entry point
3682 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3683 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3684 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3685 }
3686
3687 // For backwards compatibility with -Xrun
3688 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3689 // treated like -agentpath:
3690 // Must be called before agent libraries are created
3691 void Threads::convert_vm_init_libraries_to_agents() {
3692 AgentLibrary* agent;
3693 AgentLibrary* next;
3694
3695 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3696 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3697 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3698
3699 // If there is an JVM_OnLoad function it will get called later,
3700 // otherwise see if there is an Agent_OnLoad
3701 if (on_load_entry == NULL) {
3702 on_load_entry = lookup_agent_on_load(agent);
3703 if (on_load_entry != NULL) {
3704 // switch it to the agent list -- so that Agent_OnLoad will be called,
3705 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3706 Arguments::convert_library_to_agent(agent);
3707 } else {
3708 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3709 }
3710 }
3711 }
3712 }
3713
3714 // Create agents for -agentlib: -agentpath: and converted -Xrun
3715 // Invokes Agent_OnLoad
3716 // Called very early -- before JavaThreads exist
3717 void Threads::create_vm_init_agents() {
3718 extern struct JavaVM_ main_vm;
3719 AgentLibrary* agent;
3720
3721 JvmtiExport::enter_onload_phase();
3722
3723 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3724 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3725
3726 if (on_load_entry != NULL) {
3727 // Invoke the Agent_OnLoad function
3728 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3729 if (err != JNI_OK) {
3730 vm_exit_during_initialization("agent library failed to init", agent->name());
3731 }
3732 } else {
3733 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3734 }
3735 }
3736 JvmtiExport::enter_primordial_phase();
3737 }
3738
3739 extern "C" {
3740 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3741 }
3742
3743 void Threads::shutdown_vm_agents() {
3744 // Send any Agent_OnUnload notifications
3745 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3746 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3747 extern struct JavaVM_ main_vm;
3748 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3749
3750 // Find the Agent_OnUnload function.
3751 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3752 os::find_agent_function(agent,
3753 false,
3754 on_unload_symbols,
3755 num_symbol_entries));
3756
3757 // Invoke the Agent_OnUnload function
3758 if (unload_entry != NULL) {
3759 JavaThread* thread = JavaThread::current();
3760 ThreadToNativeFromVM ttn(thread);
3761 HandleMark hm(thread);
3762 (*unload_entry)(&main_vm);
3763 }
3764 }
3765 }
3766
3767 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3768 // Invokes JVM_OnLoad
3769 void Threads::create_vm_init_libraries() {
3770 extern struct JavaVM_ main_vm;
3771 AgentLibrary* agent;
3772
3773 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3774 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3775
3776 if (on_load_entry != NULL) {
3777 // Invoke the JVM_OnLoad function
3778 JavaThread* thread = JavaThread::current();
3779 ThreadToNativeFromVM ttn(thread);
3780 HandleMark hm(thread);
3781 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3782 if (err != JNI_OK) {
3783 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3784 }
3785 } else {
3786 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3787 }
3788 }
3789 }
3790
3791 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3792 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3793
3794 JavaThread* java_thread = NULL;
3795 // Sequential search for now. Need to do better optimization later.
3796 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3797 oop tobj = thread->threadObj();
3798 if (!thread->is_exiting() &&
3799 tobj != NULL &&
3800 java_tid == java_lang_Thread::thread_id(tobj)) {
3801 java_thread = thread;
3802 break;
3803 }
3804 }
3805 return java_thread;
3806 }
3807
3808
3809 // Last thread running calls java.lang.Shutdown.shutdown()
3810 void JavaThread::invoke_shutdown_hooks() {
3811 HandleMark hm(this);
3812
3813 // We could get here with a pending exception, if so clear it now.
3814 if (this->has_pending_exception()) {
3815 this->clear_pending_exception();
3816 }
3817
3818 EXCEPTION_MARK;
3819 Klass* k =
3820 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3821 THREAD);
3822 if (k != NULL) {
3823 // SystemDictionary::resolve_or_null will return null if there was
3824 // an exception. If we cannot load the Shutdown class, just don't
3825 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3826 // and finalizers (if runFinalizersOnExit is set) won't be run.
3827 // Note that if a shutdown hook was registered or runFinalizersOnExit
3828 // was called, the Shutdown class would have already been loaded
3829 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3830 instanceKlassHandle shutdown_klass (THREAD, k);
3831 JavaValue result(T_VOID);
3832 JavaCalls::call_static(&result,
3833 shutdown_klass,
3834 vmSymbols::shutdown_method_name(),
3835 vmSymbols::void_method_signature(),
3836 THREAD);
3837 }
3838 CLEAR_PENDING_EXCEPTION;
3839 }
3840
3841 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3842 // the program falls off the end of main(). Another VM exit path is through
3843 // vm_exit() when the program calls System.exit() to return a value or when
3844 // there is a serious error in VM. The two shutdown paths are not exactly
3845 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3846 // and VM_Exit op at VM level.
3847 //
3848 // Shutdown sequence:
3849 // + Shutdown native memory tracking if it is on
3850 // + Wait until we are the last non-daemon thread to execute
3851 // <-- every thing is still working at this moment -->
3852 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3853 // shutdown hooks, run finalizers if finalization-on-exit
3854 // + Call before_exit(), prepare for VM exit
3855 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3856 // currently the only user of this mechanism is File.deleteOnExit())
3857 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3858 // post thread end and vm death events to JVMTI,
3859 // stop signal thread
3860 // + Call JavaThread::exit(), it will:
3861 // > release JNI handle blocks, remove stack guard pages
3862 // > remove this thread from Threads list
3863 // <-- no more Java code from this thread after this point -->
3864 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3865 // the compiler threads at safepoint
3866 // <-- do not use anything that could get blocked by Safepoint -->
3867 // + Disable tracing at JNI/JVM barriers
3868 // + Set _vm_exited flag for threads that are still running native code
3869 // + Delete this thread
3870 // + Call exit_globals()
3871 // > deletes tty
3872 // > deletes PerfMemory resources
3873 // + Return to caller
3874
3875 bool Threads::destroy_vm() {
3876 JavaThread* thread = JavaThread::current();
3877
3878 #ifdef ASSERT
3879 _vm_complete = false;
3880 #endif
3881 // Wait until we are the last non-daemon thread to execute
3882 { MutexLocker nu(Threads_lock);
3883 while (Threads::number_of_non_daemon_threads() > 1)
3884 // This wait should make safepoint checks, wait without a timeout,
3885 // and wait as a suspend-equivalent condition.
3886 //
3887 // Note: If the FlatProfiler is running and this thread is waiting
3888 // for another non-daemon thread to finish, then the FlatProfiler
3889 // is waiting for the external suspend request on this thread to
3890 // complete. wait_for_ext_suspend_completion() will eventually
3891 // timeout, but that takes time. Making this wait a suspend-
3892 // equivalent condition solves that timeout problem.
3893 //
3894 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3895 Mutex::_as_suspend_equivalent_flag);
3896 }
3897
3898 // Hang forever on exit if we are reporting an error.
3899 if (ShowMessageBoxOnError && is_error_reported()) {
3900 os::infinite_sleep();
3901 }
3902 os::wait_for_keypress_at_exit();
3903
3904 // run Java level shutdown hooks
3905 thread->invoke_shutdown_hooks();
3906
3907 before_exit(thread);
3908
3909 thread->exit(true);
3910
3911 // Stop VM thread.
3912 {
3913 // 4945125 The vm thread comes to a safepoint during exit.
3914 // GC vm_operations can get caught at the safepoint, and the
3915 // heap is unparseable if they are caught. Grab the Heap_lock
3916 // to prevent this. The GC vm_operations will not be able to
3917 // queue until after the vm thread is dead. After this point,
3918 // we'll never emerge out of the safepoint before the VM exits.
3919
3920 MutexLocker ml(Heap_lock);
3921
3922 VMThread::wait_for_vm_thread_exit();
3923 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3924 VMThread::destroy();
3925 }
3926
3927 // clean up ideal graph printers
3928 #if defined(COMPILER2) && !defined(PRODUCT)
3929 IdealGraphPrinter::clean_up();
3930 #endif
3931
3932 // Now, all Java threads are gone except daemon threads. Daemon threads
3933 // running Java code or in VM are stopped by the Safepoint. However,
3934 // daemon threads executing native code are still running. But they
3935 // will be stopped at native=>Java/VM barriers. Note that we can't
3936 // simply kill or suspend them, as it is inherently deadlock-prone.
3937
3938 #ifndef PRODUCT
3939 // disable function tracing at JNI/JVM barriers
3940 TraceJNICalls = false;
3941 TraceJVMCalls = false;
3942 TraceRuntimeCalls = false;
3943 #endif
3944
3945 VM_Exit::set_vm_exited();
3946
3947 notify_vm_shutdown();
3948
3949 delete thread;
3950
3951 // exit_globals() will delete tty
3952 exit_globals();
3953
3954 return true;
3955 }
3956
3957
3958 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3959 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3960 return is_supported_jni_version(version);
3961 }
3962
3963
3964 jboolean Threads::is_supported_jni_version(jint version) {
3965 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3966 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3967 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3968 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3969 return JNI_FALSE;
3970 }
3971
3972
3973 void Threads::add(JavaThread* p, bool force_daemon) {
3974 // The threads lock must be owned at this point
3975 assert_locked_or_safepoint(Threads_lock);
3976
3977 // See the comment for this method in thread.hpp for its purpose and
3978 // why it is called here.
3979 p->initialize_queues();
3980 p->set_next(_thread_list);
3981 _thread_list = p;
3982 _number_of_threads++;
3983 oop threadObj = p->threadObj();
3984 bool daemon = true;
3985 // Bootstrapping problem: threadObj can be null for initial
3986 // JavaThread (or for threads attached via JNI)
3987 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3988 _number_of_non_daemon_threads++;
3989 daemon = false;
3990 }
3991
3992 ThreadService::add_thread(p, daemon);
3993
3994 // Possible GC point.
3995 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
3996 }
3997
3998 void Threads::remove(JavaThread* p) {
3999 // Extra scope needed for Thread_lock, so we can check
4000 // that we do not remove thread without safepoint code notice
4001 { MutexLocker ml(Threads_lock);
4002
4003 assert(includes(p), "p must be present");
4004
4005 JavaThread* current = _thread_list;
4006 JavaThread* prev = NULL;
4007
4008 while (current != p) {
4009 prev = current;
4010 current = current->next();
4011 }
4012
4013 if (prev) {
4014 prev->set_next(current->next());
4015 } else {
4016 _thread_list = p->next();
4017 }
4018 _number_of_threads--;
4019 oop threadObj = p->threadObj();
4020 bool daemon = true;
4021 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4022 _number_of_non_daemon_threads--;
4023 daemon = false;
4024
4025 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4026 // on destroy_vm will wake up.
4027 if (number_of_non_daemon_threads() == 1) {
4028 Threads_lock->notify_all();
4029 }
4030 }
4031 ThreadService::remove_thread(p, daemon);
4032
4033 // Make sure that safepoint code disregard this thread. This is needed since
4034 // the thread might mess around with locks after this point. This can cause it
4035 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4036 // of this thread since it is removed from the queue.
4037 p->set_terminated_value();
4038 } // unlock Threads_lock
4039
4040 // Since Events::log uses a lock, we grab it outside the Threads_lock
4041 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4042 }
4043
4044 // Threads_lock must be held when this is called (or must be called during a safepoint)
4045 bool Threads::includes(JavaThread* p) {
4046 assert(Threads_lock->is_locked(), "sanity check");
4047 ALL_JAVA_THREADS(q) {
4048 if (q == p) {
4049 return true;
4050 }
4051 }
4052 return false;
4053 }
4054
4055 // Operations on the Threads list for GC. These are not explicitly locked,
4056 // but the garbage collector must provide a safe context for them to run.
4057 // In particular, these things should never be called when the Threads_lock
4058 // is held by some other thread. (Note: the Safepoint abstraction also
4059 // uses the Threads_lock to guarantee this property. It also makes sure that
4060 // all threads gets blocked when exiting or starting).
4061
4062 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4063 ALL_JAVA_THREADS(p) {
4064 p->oops_do(f, cld_f, cf);
4065 }
4066 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4067 }
4068
4069 void Threads::change_thread_claim_parity() {
4070 // Set the new claim parity.
4071 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4072 "Not in range.");
4073 _thread_claim_parity++;
4074 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4075 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4076 "Not in range.");
4077 }
4078
4079 #ifdef ASSERT
4080 void Threads::assert_all_threads_claimed() {
4081 ALL_JAVA_THREADS(p) {
4082 const int thread_parity = p->oops_do_parity();
4083 assert((thread_parity == _thread_claim_parity),
4084 err_msg("Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity));
4085 }
4086 }
4087 #endif // ASSERT
4088
4089 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4090 int cp = Threads::thread_claim_parity();
4091 ALL_JAVA_THREADS(p) {
4092 if (p->claim_oops_do(is_par, cp)) {
4093 p->oops_do(f, cld_f, cf);
4094 }
4095 }
4096 VMThread* vmt = VMThread::vm_thread();
4097 if (vmt->claim_oops_do(is_par, cp)) {
4098 vmt->oops_do(f, cld_f, cf);
4099 }
4100 }
4101
4102 #if INCLUDE_ALL_GCS
4103 // Used by ParallelScavenge
4104 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4105 ALL_JAVA_THREADS(p) {
4106 q->enqueue(new ThreadRootsTask(p));
4107 }
4108 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4109 }
4110
4111 // Used by Parallel Old
4112 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4113 ALL_JAVA_THREADS(p) {
4114 q->enqueue(new ThreadRootsMarkingTask(p));
4115 }
4116 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4117 }
4118 #endif // INCLUDE_ALL_GCS
4119
4120 void Threads::nmethods_do(CodeBlobClosure* cf) {
4121 ALL_JAVA_THREADS(p) {
4122 p->nmethods_do(cf);
4123 }
4124 VMThread::vm_thread()->nmethods_do(cf);
4125 }
4126
4127 void Threads::metadata_do(void f(Metadata*)) {
4128 ALL_JAVA_THREADS(p) {
4129 p->metadata_do(f);
4130 }
4131 }
4132
4133 class ThreadHandlesClosure : public ThreadClosure {
4134 void (*_f)(Metadata*);
4135 public:
4136 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4137 virtual void do_thread(Thread* thread) {
4138 thread->metadata_handles_do(_f);
4139 }
4140 };
4141
4142 void Threads::metadata_handles_do(void f(Metadata*)) {
4143 // Only walk the Handles in Thread.
4144 ThreadHandlesClosure handles_closure(f);
4145 threads_do(&handles_closure);
4146 }
4147
4148 void Threads::deoptimized_wrt_marked_nmethods() {
4149 ALL_JAVA_THREADS(p) {
4150 p->deoptimized_wrt_marked_nmethods();
4151 }
4152 }
4153
4154
4155 // Get count Java threads that are waiting to enter the specified monitor.
4156 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4157 address monitor,
4158 bool doLock) {
4159 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4160 "must grab Threads_lock or be at safepoint");
4161 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4162
4163 int i = 0;
4164 {
4165 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4166 ALL_JAVA_THREADS(p) {
4167 if (p->is_Compiler_thread()) continue;
4168
4169 address pending = (address)p->current_pending_monitor();
4170 if (pending == monitor) { // found a match
4171 if (i < count) result->append(p); // save the first count matches
4172 i++;
4173 }
4174 }
4175 }
4176 return result;
4177 }
4178
4179
4180 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4181 bool doLock) {
4182 assert(doLock ||
4183 Threads_lock->owned_by_self() ||
4184 SafepointSynchronize::is_at_safepoint(),
4185 "must grab Threads_lock or be at safepoint");
4186
4187 // NULL owner means not locked so we can skip the search
4188 if (owner == NULL) return NULL;
4189
4190 {
4191 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4192 ALL_JAVA_THREADS(p) {
4193 // first, see if owner is the address of a Java thread
4194 if (owner == (address)p) return p;
4195 }
4196 }
4197 // Cannot assert on lack of success here since this function may be
4198 // used by code that is trying to report useful problem information
4199 // like deadlock detection.
4200 if (UseHeavyMonitors) return NULL;
4201
4202 // If we didn't find a matching Java thread and we didn't force use of
4203 // heavyweight monitors, then the owner is the stack address of the
4204 // Lock Word in the owning Java thread's stack.
4205 //
4206 JavaThread* the_owner = NULL;
4207 {
4208 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4209 ALL_JAVA_THREADS(q) {
4210 if (q->is_lock_owned(owner)) {
4211 the_owner = q;
4212 break;
4213 }
4214 }
4215 }
4216 // cannot assert on lack of success here; see above comment
4217 return the_owner;
4218 }
4219
4220 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4221 void Threads::print_on(outputStream* st, bool print_stacks,
4222 bool internal_format, bool print_concurrent_locks) {
4223 char buf[32];
4224 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4225
4226 st->print_cr("Full thread dump %s (%s %s):",
4227 Abstract_VM_Version::vm_name(),
4228 Abstract_VM_Version::vm_release(),
4229 Abstract_VM_Version::vm_info_string());
4230 st->cr();
4231
4232 #if INCLUDE_SERVICES
4233 // Dump concurrent locks
4234 ConcurrentLocksDump concurrent_locks;
4235 if (print_concurrent_locks) {
4236 concurrent_locks.dump_at_safepoint();
4237 }
4238 #endif // INCLUDE_SERVICES
4239
4240 ALL_JAVA_THREADS(p) {
4241 ResourceMark rm;
4242 p->print_on(st);
4243 if (print_stacks) {
4244 if (internal_format) {
4245 p->trace_stack();
4246 } else {
4247 p->print_stack_on(st);
4248 }
4249 }
4250 st->cr();
4251 #if INCLUDE_SERVICES
4252 if (print_concurrent_locks) {
4253 concurrent_locks.print_locks_on(p, st);
4254 }
4255 #endif // INCLUDE_SERVICES
4256 }
4257
4258 VMThread::vm_thread()->print_on(st);
4259 st->cr();
4260 Universe::heap()->print_gc_threads_on(st);
4261 WatcherThread* wt = WatcherThread::watcher_thread();
4262 if (wt != NULL) {
4263 wt->print_on(st);
4264 st->cr();
4265 }
4266 CompileBroker::print_compiler_threads_on(st);
4267 st->flush();
4268 }
4269
4270 // Threads::print_on_error() is called by fatal error handler. It's possible
4271 // that VM is not at safepoint and/or current thread is inside signal handler.
4272 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4273 // memory (even in resource area), it might deadlock the error handler.
4274 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4275 int buflen) {
4276 bool found_current = false;
4277 st->print_cr("Java Threads: ( => current thread )");
4278 ALL_JAVA_THREADS(thread) {
4279 bool is_current = (current == thread);
4280 found_current = found_current || is_current;
4281
4282 st->print("%s", is_current ? "=>" : " ");
4283
4284 st->print(PTR_FORMAT, thread);
4285 st->print(" ");
4286 thread->print_on_error(st, buf, buflen);
4287 st->cr();
4288 }
4289 st->cr();
4290
4291 st->print_cr("Other Threads:");
4292 if (VMThread::vm_thread()) {
4293 bool is_current = (current == VMThread::vm_thread());
4294 found_current = found_current || is_current;
4295 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4296
4297 st->print(PTR_FORMAT, VMThread::vm_thread());
4298 st->print(" ");
4299 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4300 st->cr();
4301 }
4302 WatcherThread* wt = WatcherThread::watcher_thread();
4303 if (wt != NULL) {
4304 bool is_current = (current == wt);
4305 found_current = found_current || is_current;
4306 st->print("%s", is_current ? "=>" : " ");
4307
4308 st->print(PTR_FORMAT, wt);
4309 st->print(" ");
4310 wt->print_on_error(st, buf, buflen);
4311 st->cr();
4312 }
4313 if (!found_current) {
4314 st->cr();
4315 st->print("=>" PTR_FORMAT " (exited) ", current);
4316 current->print_on_error(st, buf, buflen);
4317 st->cr();
4318 }
4319 }
4320
4321 // Internal SpinLock and Mutex
4322 // Based on ParkEvent
4323
4324 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4325 //
4326 // We employ SpinLocks _only for low-contention, fixed-length
4327 // short-duration critical sections where we're concerned
4328 // about native mutex_t or HotSpot Mutex:: latency.
4329 // The mux construct provides a spin-then-block mutual exclusion
4330 // mechanism.
4331 //
4332 // Testing has shown that contention on the ListLock guarding gFreeList
4333 // is common. If we implement ListLock as a simple SpinLock it's common
4334 // for the JVM to devolve to yielding with little progress. This is true
4335 // despite the fact that the critical sections protected by ListLock are
4336 // extremely short.
4337 //
4338 // TODO-FIXME: ListLock should be of type SpinLock.
4339 // We should make this a 1st-class type, integrated into the lock
4340 // hierarchy as leaf-locks. Critically, the SpinLock structure
4341 // should have sufficient padding to avoid false-sharing and excessive
4342 // cache-coherency traffic.
4343
4344
4345 typedef volatile int SpinLockT;
4346
4347 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4348 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4349 return; // normal fast-path return
4350 }
4351
4352 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4353 TEVENT(SpinAcquire - ctx);
4354 int ctr = 0;
4355 int Yields = 0;
4356 for (;;) {
4357 while (*adr != 0) {
4358 ++ctr;
4359 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4360 if (Yields > 5) {
4361 os::naked_short_sleep(1);
4362 } else {
4363 os::naked_yield();
4364 ++Yields;
4365 }
4366 } else {
4367 SpinPause();
4368 }
4369 }
4370 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4371 }
4372 }
4373
4374 void Thread::SpinRelease(volatile int * adr) {
4375 assert(*adr != 0, "invariant");
4376 OrderAccess::fence(); // guarantee at least release consistency.
4377 // Roach-motel semantics.
4378 // It's safe if subsequent LDs and STs float "up" into the critical section,
4379 // but prior LDs and STs within the critical section can't be allowed
4380 // to reorder or float past the ST that releases the lock.
4381 // Loads and stores in the critical section - which appear in program
4382 // order before the store that releases the lock - must also appear
4383 // before the store that releases the lock in memory visibility order.
4384 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4385 // the ST of 0 into the lock-word which releases the lock, so fence
4386 // more than covers this on all platforms.
4387 *adr = 0;
4388 }
4389
4390 // muxAcquire and muxRelease:
4391 //
4392 // * muxAcquire and muxRelease support a single-word lock-word construct.
4393 // The LSB of the word is set IFF the lock is held.
4394 // The remainder of the word points to the head of a singly-linked list
4395 // of threads blocked on the lock.
4396 //
4397 // * The current implementation of muxAcquire-muxRelease uses its own
4398 // dedicated Thread._MuxEvent instance. If we're interested in
4399 // minimizing the peak number of extant ParkEvent instances then
4400 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4401 // as certain invariants were satisfied. Specifically, care would need
4402 // to be taken with regards to consuming unpark() "permits".
4403 // A safe rule of thumb is that a thread would never call muxAcquire()
4404 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4405 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4406 // consume an unpark() permit intended for monitorenter, for instance.
4407 // One way around this would be to widen the restricted-range semaphore
4408 // implemented in park(). Another alternative would be to provide
4409 // multiple instances of the PlatformEvent() for each thread. One
4410 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4411 //
4412 // * Usage:
4413 // -- Only as leaf locks
4414 // -- for short-term locking only as muxAcquire does not perform
4415 // thread state transitions.
4416 //
4417 // Alternatives:
4418 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4419 // but with parking or spin-then-park instead of pure spinning.
4420 // * Use Taura-Oyama-Yonenzawa locks.
4421 // * It's possible to construct a 1-0 lock if we encode the lockword as
4422 // (List,LockByte). Acquire will CAS the full lockword while Release
4423 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4424 // acquiring threads use timers (ParkTimed) to detect and recover from
4425 // the stranding window. Thread/Node structures must be aligned on 256-byte
4426 // boundaries by using placement-new.
4427 // * Augment MCS with advisory back-link fields maintained with CAS().
4428 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4429 // The validity of the backlinks must be ratified before we trust the value.
4430 // If the backlinks are invalid the exiting thread must back-track through the
4431 // the forward links, which are always trustworthy.
4432 // * Add a successor indication. The LockWord is currently encoded as
4433 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4434 // to provide the usual futile-wakeup optimization.
4435 // See RTStt for details.
4436 // * Consider schedctl.sc_nopreempt to cover the critical section.
4437 //
4438
4439
4440 typedef volatile intptr_t MutexT; // Mux Lock-word
4441 enum MuxBits { LOCKBIT = 1 };
4442
4443 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4444 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4445 if (w == 0) return;
4446 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4447 return;
4448 }
4449
4450 TEVENT(muxAcquire - Contention);
4451 ParkEvent * const Self = Thread::current()->_MuxEvent;
4452 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4453 for (;;) {
4454 int its = (os::is_MP() ? 100 : 0) + 1;
4455
4456 // Optional spin phase: spin-then-park strategy
4457 while (--its >= 0) {
4458 w = *Lock;
4459 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4460 return;
4461 }
4462 }
4463
4464 Self->reset();
4465 Self->OnList = intptr_t(Lock);
4466 // The following fence() isn't _strictly necessary as the subsequent
4467 // CAS() both serializes execution and ratifies the fetched *Lock value.
4468 OrderAccess::fence();
4469 for (;;) {
4470 w = *Lock;
4471 if ((w & LOCKBIT) == 0) {
4472 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4473 Self->OnList = 0; // hygiene - allows stronger asserts
4474 return;
4475 }
4476 continue; // Interference -- *Lock changed -- Just retry
4477 }
4478 assert(w & LOCKBIT, "invariant");
4479 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4480 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4481 }
4482
4483 while (Self->OnList != 0) {
4484 Self->park();
4485 }
4486 }
4487 }
4488
4489 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4490 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4491 if (w == 0) return;
4492 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4493 return;
4494 }
4495
4496 TEVENT(muxAcquire - Contention);
4497 ParkEvent * ReleaseAfter = NULL;
4498 if (ev == NULL) {
4499 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4500 }
4501 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4502 for (;;) {
4503 guarantee(ev->OnList == 0, "invariant");
4504 int its = (os::is_MP() ? 100 : 0) + 1;
4505
4506 // Optional spin phase: spin-then-park strategy
4507 while (--its >= 0) {
4508 w = *Lock;
4509 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4510 if (ReleaseAfter != NULL) {
4511 ParkEvent::Release(ReleaseAfter);
4512 }
4513 return;
4514 }
4515 }
4516
4517 ev->reset();
4518 ev->OnList = intptr_t(Lock);
4519 // The following fence() isn't _strictly necessary as the subsequent
4520 // CAS() both serializes execution and ratifies the fetched *Lock value.
4521 OrderAccess::fence();
4522 for (;;) {
4523 w = *Lock;
4524 if ((w & LOCKBIT) == 0) {
4525 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4526 ev->OnList = 0;
4527 // We call ::Release while holding the outer lock, thus
4528 // artificially lengthening the critical section.
4529 // Consider deferring the ::Release() until the subsequent unlock(),
4530 // after we've dropped the outer lock.
4531 if (ReleaseAfter != NULL) {
4532 ParkEvent::Release(ReleaseAfter);
4533 }
4534 return;
4535 }
4536 continue; // Interference -- *Lock changed -- Just retry
4537 }
4538 assert(w & LOCKBIT, "invariant");
4539 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4540 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4541 }
4542
4543 while (ev->OnList != 0) {
4544 ev->park();
4545 }
4546 }
4547 }
4548
4549 // Release() must extract a successor from the list and then wake that thread.
4550 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4551 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4552 // Release() would :
4553 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4554 // (B) Extract a successor from the private list "in-hand"
4555 // (C) attempt to CAS() the residual back into *Lock over null.
4556 // If there were any newly arrived threads and the CAS() would fail.
4557 // In that case Release() would detach the RATs, re-merge the list in-hand
4558 // with the RATs and repeat as needed. Alternately, Release() might
4559 // detach and extract a successor, but then pass the residual list to the wakee.
4560 // The wakee would be responsible for reattaching and remerging before it
4561 // competed for the lock.
4562 //
4563 // Both "pop" and DMR are immune from ABA corruption -- there can be
4564 // multiple concurrent pushers, but only one popper or detacher.
4565 // This implementation pops from the head of the list. This is unfair,
4566 // but tends to provide excellent throughput as hot threads remain hot.
4567 // (We wake recently run threads first).
4568 //
4569 // All paths through muxRelease() will execute a CAS.
4570 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4571 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4572 // executed within the critical section are complete and globally visible before the
4573 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4574 void Thread::muxRelease(volatile intptr_t * Lock) {
4575 for (;;) {
4576 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4577 assert(w & LOCKBIT, "invariant");
4578 if (w == LOCKBIT) return;
4579 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4580 assert(List != NULL, "invariant");
4581 assert(List->OnList == intptr_t(Lock), "invariant");
4582 ParkEvent * const nxt = List->ListNext;
4583 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4584
4585 // The following CAS() releases the lock and pops the head element.
4586 // The CAS() also ratifies the previously fetched lock-word value.
4587 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4588 continue;
4589 }
4590 List->OnList = 0;
4591 OrderAccess::fence();
4592 List->unpark();
4593 return;
4594 }
4595 }
4596
4597
4598 void Threads::verify() {
4599 ALL_JAVA_THREADS(p) {
4600 p->verify();
4601 }
4602 VMThread* thread = VMThread::vm_thread();
4603 if (thread != NULL) thread->verify();
4604 }