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/gcId.hpp"
35 #include "gc/shared/gcLocker.inline.hpp"
36 #include "gc/shared/workgroup.hpp"
37 #include "interpreter/interpreter.hpp"
38 #include "interpreter/linkResolver.hpp"
39 #include "interpreter/oopMapCache.hpp"
40 #include "jvmtifiles/jvmtiEnv.hpp"
41 #include "logging/logConfiguration.hpp"
42 #include "memory/metaspaceShared.hpp"
43 #include "memory/oopFactory.hpp"
44 #include "memory/universe.inline.hpp"
45 #include "oops/instanceKlass.hpp"
46 #include "oops/objArrayOop.hpp"
47 #include "oops/oop.inline.hpp"
48 #include "oops/symbol.hpp"
49 #include "oops/verifyOopClosure.hpp"
50 #include "prims/jvm_misc.hpp"
51 #include "prims/jvmtiExport.hpp"
52 #include "prims/jvmtiThreadState.hpp"
53 #include "prims/privilegedStack.hpp"
54 #include "runtime/arguments.hpp"
55 #include "runtime/atomic.inline.hpp"
56 #include "runtime/biasedLocking.hpp"
57 #include "runtime/commandLineFlagConstraintList.hpp"
58 #include "runtime/commandLineFlagRangeList.hpp"
59 #include "runtime/deoptimization.hpp"
60 #include "runtime/fprofiler.hpp"
61 #include "runtime/frame.inline.hpp"
62 #include "runtime/globals.hpp"
63 #include "runtime/init.hpp"
64 #include "runtime/interfaceSupport.hpp"
65 #include "runtime/java.hpp"
66 #include "runtime/javaCalls.hpp"
67 #include "runtime/jniPeriodicChecker.hpp"
68 #include "runtime/memprofiler.hpp"
69 #include "runtime/mutexLocker.hpp"
70 #include "runtime/objectMonitor.hpp"
71 #include "runtime/orderAccess.inline.hpp"
72 #include "runtime/osThread.hpp"
73 #include "runtime/safepoint.hpp"
74 #include "runtime/sharedRuntime.hpp"
75 #include "runtime/statSampler.hpp"
76 #include "runtime/stubRoutines.hpp"
77 #include "runtime/sweeper.hpp"
78 #include "runtime/task.hpp"
79 #include "runtime/thread.inline.hpp"
80 #include "runtime/threadCritical.hpp"
81 #include "runtime/vframe.hpp"
82 #include "runtime/vframeArray.hpp"
83 #include "runtime/vframe_hp.hpp"
84 #include "runtime/vmThread.hpp"
85 #include "runtime/vm_operations.hpp"
86 #include "runtime/vm_version.hpp"
87 #include "services/attachListener.hpp"
88 #include "services/management.hpp"
89 #include "services/memTracker.hpp"
90 #include "services/threadService.hpp"
91 #include "trace/traceMacros.hpp"
92 #include "trace/tracing.hpp"
93 #include "utilities/defaultStream.hpp"
94 #include "utilities/dtrace.hpp"
95 #include "utilities/events.hpp"
96 #include "utilities/macros.hpp"
97 #include "utilities/preserveException.hpp"
98 #if INCLUDE_ALL_GCS
99 #include "gc/cms/concurrentMarkSweepThread.hpp"
100 #include "gc/g1/concurrentMarkThread.inline.hpp"
101 #include "gc/parallel/pcTasks.hpp"
102 #endif // INCLUDE_ALL_GCS
103 #if INCLUDE_JVMCI
104 #include "jvmci/jvmciCompiler.hpp"
105 #include "jvmci/jvmciRuntime.hpp"
106 #endif
107 #ifdef COMPILER1
108 #include "c1/c1_Compiler.hpp"
109 #endif
110 #ifdef COMPILER2
111 #include "opto/c2compiler.hpp"
112 #include "opto/idealGraphPrinter.hpp"
113 #endif
114 #if INCLUDE_RTM_OPT
115 #include "runtime/rtmLocking.hpp"
116 #endif
117
118 #ifdef DTRACE_ENABLED
119
120 // Only bother with this argument setup if dtrace is available
121
122 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
123 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
124
125 #define DTRACE_THREAD_PROBE(probe, javathread) \
126 { \
127 ResourceMark rm(this); \
128 int len = 0; \
129 const char* name = (javathread)->get_thread_name(); \
130 len = strlen(name); \
131 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
132 (char *) name, len, \
133 java_lang_Thread::thread_id((javathread)->threadObj()), \
134 (uintptr_t) (javathread)->osthread()->thread_id(), \
135 java_lang_Thread::is_daemon((javathread)->threadObj())); \
136 }
137
138 #else // ndef DTRACE_ENABLED
139
140 #define DTRACE_THREAD_PROBE(probe, javathread)
141
142 #endif // ndef DTRACE_ENABLED
143
144 #ifndef USE_LIBRARY_BASED_TLS_ONLY
145 // Current thread is maintained as a thread-local variable
146 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
147 #endif
148
149 // Class hierarchy
150 // - Thread
151 // - VMThread
152 // - WatcherThread
153 // - ConcurrentMarkSweepThread
154 // - JavaThread
155 // - CompilerThread
156
157 // ======= Thread ========
158 // Support for forcing alignment of thread objects for biased locking
159 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
160 if (UseBiasedLocking) {
161 const int alignment = markOopDesc::biased_lock_alignment;
162 size_t aligned_size = size + (alignment - sizeof(intptr_t));
163 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
164 : AllocateHeap(aligned_size, flags, CURRENT_PC,
165 AllocFailStrategy::RETURN_NULL);
166 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
167 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
168 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
169 "JavaThread alignment code overflowed allocated storage");
170 if (TraceBiasedLocking) {
171 if (aligned_addr != real_malloc_addr) {
172 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
173 p2i(real_malloc_addr), p2i(aligned_addr));
174 }
175 }
176 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
177 return aligned_addr;
178 } else {
179 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
180 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
181 }
182 }
183
184 void Thread::operator delete(void* p) {
185 if (UseBiasedLocking) {
186 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
187 FreeHeap(real_malloc_addr);
188 } else {
189 FreeHeap(p);
190 }
191 }
192
193
194 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
195 // JavaThread
196
197
198 Thread::Thread() {
199 // stack and get_thread
200 set_stack_base(NULL);
201 set_stack_size(0);
202 set_self_raw_id(0);
203 set_lgrp_id(-1);
204 DEBUG_ONLY(clear_suspendible_thread();)
205
206 // allocated data structures
207 set_osthread(NULL);
208 set_resource_area(new (mtThread)ResourceArea());
209 DEBUG_ONLY(_current_resource_mark = NULL;)
210 set_handle_area(new (mtThread) HandleArea(NULL));
211 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
212 set_active_handles(NULL);
213 set_free_handle_block(NULL);
214 set_last_handle_mark(NULL);
215
216 // This initial value ==> never claimed.
217 _oops_do_parity = 0;
218
219 // the handle mark links itself to last_handle_mark
220 new HandleMark(this);
221
222 // plain initialization
223 debug_only(_owned_locks = NULL;)
224 debug_only(_allow_allocation_count = 0;)
225 NOT_PRODUCT(_allow_safepoint_count = 0;)
226 NOT_PRODUCT(_skip_gcalot = false;)
227 _jvmti_env_iteration_count = 0;
228 set_allocated_bytes(0);
229 _vm_operation_started_count = 0;
230 _vm_operation_completed_count = 0;
231 _current_pending_monitor = NULL;
232 _current_pending_monitor_is_from_java = true;
233 _current_waiting_monitor = NULL;
234 _num_nested_signal = 0;
235 omFreeList = NULL;
236 omFreeCount = 0;
237 omFreeProvision = 32;
238 omInUseList = NULL;
239 omInUseCount = 0;
240
241 #ifdef ASSERT
242 _visited_for_critical_count = false;
243 #endif
244
245 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
246 Monitor::_safepoint_check_sometimes);
247 _suspend_flags = 0;
248
249 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
250 _hashStateX = os::random();
251 _hashStateY = 842502087;
252 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
253 _hashStateW = 273326509;
254
255 _OnTrap = 0;
256 _schedctl = NULL;
257 _Stalled = 0;
258 _TypeTag = 0x2BAD;
259
260 // Many of the following fields are effectively final - immutable
261 // Note that nascent threads can't use the Native Monitor-Mutex
262 // construct until the _MutexEvent is initialized ...
263 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
264 // we might instead use a stack of ParkEvents that we could provision on-demand.
265 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
266 // and ::Release()
267 _ParkEvent = ParkEvent::Allocate(this);
268 _SleepEvent = ParkEvent::Allocate(this);
269 _MutexEvent = ParkEvent::Allocate(this);
270 _MuxEvent = ParkEvent::Allocate(this);
271
272 #ifdef CHECK_UNHANDLED_OOPS
273 if (CheckUnhandledOops) {
274 _unhandled_oops = new UnhandledOops(this);
275 }
276 #endif // CHECK_UNHANDLED_OOPS
277 #ifdef ASSERT
278 if (UseBiasedLocking) {
279 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
280 assert(this == _real_malloc_address ||
281 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
282 "bug in forced alignment of thread objects");
283 }
284 #endif // ASSERT
285 }
286
287 void Thread::initialize_thread_current() {
288 #ifndef USE_LIBRARY_BASED_TLS_ONLY
289 assert(_thr_current == NULL, "Thread::current already initialized");
290 _thr_current = this;
291 #endif
292 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
293 ThreadLocalStorage::set_thread(this);
294 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
295 }
296
297 void Thread::clear_thread_current() {
298 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
299 #ifndef USE_LIBRARY_BASED_TLS_ONLY
300 _thr_current = NULL;
301 #endif
302 ThreadLocalStorage::set_thread(NULL);
303 }
304
305 void Thread::record_stack_base_and_size() {
306 set_stack_base(os::current_stack_base());
307 set_stack_size(os::current_stack_size());
308 if (is_Java_thread()) {
309 ((JavaThread*) this)->set_stack_overflow_limit();
310 }
311 // CR 7190089: on Solaris, primordial thread's stack is adjusted
312 // in initialize_thread(). Without the adjustment, stack size is
313 // incorrect if stack is set to unlimited (ulimit -s unlimited).
314 // So far, only Solaris has real implementation of initialize_thread().
315 //
316 // set up any platform-specific state.
317 os::initialize_thread(this);
318
319 #if INCLUDE_NMT
320 // record thread's native stack, stack grows downward
321 address stack_low_addr = stack_base() - stack_size();
322 MemTracker::record_thread_stack(stack_low_addr, stack_size());
323 #endif // INCLUDE_NMT
324 }
325
326
327 Thread::~Thread() {
328 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
329 ObjectSynchronizer::omFlush(this);
330
331 EVENT_THREAD_DESTRUCT(this);
332
333 // stack_base can be NULL if the thread is never started or exited before
334 // record_stack_base_and_size called. Although, we would like to ensure
335 // that all started threads do call record_stack_base_and_size(), there is
336 // not proper way to enforce that.
337 #if INCLUDE_NMT
338 if (_stack_base != NULL) {
339 address low_stack_addr = stack_base() - stack_size();
340 MemTracker::release_thread_stack(low_stack_addr, stack_size());
341 #ifdef ASSERT
342 set_stack_base(NULL);
343 #endif
344 }
345 #endif // INCLUDE_NMT
346
347 // deallocate data structures
348 delete resource_area();
349 // since the handle marks are using the handle area, we have to deallocated the root
350 // handle mark before deallocating the thread's handle area,
351 assert(last_handle_mark() != NULL, "check we have an element");
352 delete last_handle_mark();
353 assert(last_handle_mark() == NULL, "check we have reached the end");
354
355 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
356 // We NULL out the fields for good hygiene.
357 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
358 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
359 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
360 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
361
362 delete handle_area();
363 delete metadata_handles();
364
365 // osthread() can be NULL, if creation of thread failed.
366 if (osthread() != NULL) os::free_thread(osthread());
367
368 delete _SR_lock;
369
370 // clear Thread::current if thread is deleting itself.
371 // Needed to ensure JNI correctly detects non-attached threads.
372 if (this == Thread::current()) {
373 clear_thread_current();
374 }
375
376 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
377 }
378
379 // NOTE: dummy function for assertion purpose.
380 void Thread::run() {
381 ShouldNotReachHere();
382 }
383
384 #ifdef ASSERT
385 // Private method to check for dangling thread pointer
386 void check_for_dangling_thread_pointer(Thread *thread) {
387 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
388 "possibility of dangling Thread pointer");
389 }
390 #endif
391
392 ThreadPriority Thread::get_priority(const Thread* const thread) {
393 ThreadPriority priority;
394 // Can return an error!
395 (void)os::get_priority(thread, priority);
396 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
397 return priority;
398 }
399
400 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
401 debug_only(check_for_dangling_thread_pointer(thread);)
402 // Can return an error!
403 (void)os::set_priority(thread, priority);
404 }
405
406
407 void Thread::start(Thread* thread) {
408 // Start is different from resume in that its safety is guaranteed by context or
409 // being called from a Java method synchronized on the Thread object.
410 if (!DisableStartThread) {
411 if (thread->is_Java_thread()) {
412 // Initialize the thread state to RUNNABLE before starting this thread.
413 // Can not set it after the thread started because we do not know the
414 // exact thread state at that time. It could be in MONITOR_WAIT or
415 // in SLEEPING or some other state.
416 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
417 java_lang_Thread::RUNNABLE);
418 }
419 os::start_thread(thread);
420 }
421 }
422
423 // Enqueue a VM_Operation to do the job for us - sometime later
424 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
425 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
426 VMThread::execute(vm_stop);
427 }
428
429
430 // Check if an external suspend request has completed (or has been
431 // cancelled). Returns true if the thread is externally suspended and
432 // false otherwise.
433 //
434 // The bits parameter returns information about the code path through
435 // the routine. Useful for debugging:
436 //
437 // set in is_ext_suspend_completed():
438 // 0x00000001 - routine was entered
439 // 0x00000010 - routine return false at end
440 // 0x00000100 - thread exited (return false)
441 // 0x00000200 - suspend request cancelled (return false)
442 // 0x00000400 - thread suspended (return true)
443 // 0x00001000 - thread is in a suspend equivalent state (return true)
444 // 0x00002000 - thread is native and walkable (return true)
445 // 0x00004000 - thread is native_trans and walkable (needed retry)
446 //
447 // set in wait_for_ext_suspend_completion():
448 // 0x00010000 - routine was entered
449 // 0x00020000 - suspend request cancelled before loop (return false)
450 // 0x00040000 - thread suspended before loop (return true)
451 // 0x00080000 - suspend request cancelled in loop (return false)
452 // 0x00100000 - thread suspended in loop (return true)
453 // 0x00200000 - suspend not completed during retry loop (return false)
454
455 // Helper class for tracing suspend wait debug bits.
456 //
457 // 0x00000100 indicates that the target thread exited before it could
458 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
459 // 0x00080000 each indicate a cancelled suspend request so they don't
460 // count as wait failures either.
461 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
462
463 class TraceSuspendDebugBits : public StackObj {
464 private:
465 JavaThread * jt;
466 bool is_wait;
467 bool called_by_wait; // meaningful when !is_wait
468 uint32_t * bits;
469
470 public:
471 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
472 uint32_t *_bits) {
473 jt = _jt;
474 is_wait = _is_wait;
475 called_by_wait = _called_by_wait;
476 bits = _bits;
477 }
478
479 ~TraceSuspendDebugBits() {
480 if (!is_wait) {
481 #if 1
482 // By default, don't trace bits for is_ext_suspend_completed() calls.
483 // That trace is very chatty.
484 return;
485 #else
486 if (!called_by_wait) {
487 // If tracing for is_ext_suspend_completed() is enabled, then only
488 // trace calls to it from wait_for_ext_suspend_completion()
489 return;
490 }
491 #endif
492 }
493
494 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
495 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
496 MutexLocker ml(Threads_lock); // needed for get_thread_name()
497 ResourceMark rm;
498
499 tty->print_cr(
500 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
501 jt->get_thread_name(), *bits);
502
503 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
504 }
505 }
506 }
507 };
508 #undef DEBUG_FALSE_BITS
509
510
511 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
512 uint32_t *bits) {
513 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
514
515 bool did_trans_retry = false; // only do thread_in_native_trans retry once
516 bool do_trans_retry; // flag to force the retry
517
518 *bits |= 0x00000001;
519
520 do {
521 do_trans_retry = false;
522
523 if (is_exiting()) {
524 // Thread is in the process of exiting. This is always checked
525 // first to reduce the risk of dereferencing a freed JavaThread.
526 *bits |= 0x00000100;
527 return false;
528 }
529
530 if (!is_external_suspend()) {
531 // Suspend request is cancelled. This is always checked before
532 // is_ext_suspended() to reduce the risk of a rogue resume
533 // confusing the thread that made the suspend request.
534 *bits |= 0x00000200;
535 return false;
536 }
537
538 if (is_ext_suspended()) {
539 // thread is suspended
540 *bits |= 0x00000400;
541 return true;
542 }
543
544 // Now that we no longer do hard suspends of threads running
545 // native code, the target thread can be changing thread state
546 // while we are in this routine:
547 //
548 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
549 //
550 // We save a copy of the thread state as observed at this moment
551 // and make our decision about suspend completeness based on the
552 // copy. This closes the race where the thread state is seen as
553 // _thread_in_native_trans in the if-thread_blocked check, but is
554 // seen as _thread_blocked in if-thread_in_native_trans check.
555 JavaThreadState save_state = thread_state();
556
557 if (save_state == _thread_blocked && is_suspend_equivalent()) {
558 // If the thread's state is _thread_blocked and this blocking
559 // condition is known to be equivalent to a suspend, then we can
560 // consider the thread to be externally suspended. This means that
561 // the code that sets _thread_blocked has been modified to do
562 // self-suspension if the blocking condition releases. We also
563 // used to check for CONDVAR_WAIT here, but that is now covered by
564 // the _thread_blocked with self-suspension check.
565 //
566 // Return true since we wouldn't be here unless there was still an
567 // external suspend request.
568 *bits |= 0x00001000;
569 return true;
570 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
571 // Threads running native code will self-suspend on native==>VM/Java
572 // transitions. If its stack is walkable (should always be the case
573 // unless this function is called before the actual java_suspend()
574 // call), then the wait is done.
575 *bits |= 0x00002000;
576 return true;
577 } else if (!called_by_wait && !did_trans_retry &&
578 save_state == _thread_in_native_trans &&
579 frame_anchor()->walkable()) {
580 // The thread is transitioning from thread_in_native to another
581 // thread state. check_safepoint_and_suspend_for_native_trans()
582 // will force the thread to self-suspend. If it hasn't gotten
583 // there yet we may have caught the thread in-between the native
584 // code check above and the self-suspend. Lucky us. If we were
585 // called by wait_for_ext_suspend_completion(), then it
586 // will be doing the retries so we don't have to.
587 //
588 // Since we use the saved thread state in the if-statement above,
589 // there is a chance that the thread has already transitioned to
590 // _thread_blocked by the time we get here. In that case, we will
591 // make a single unnecessary pass through the logic below. This
592 // doesn't hurt anything since we still do the trans retry.
593
594 *bits |= 0x00004000;
595
596 // Once the thread leaves thread_in_native_trans for another
597 // thread state, we break out of this retry loop. We shouldn't
598 // need this flag to prevent us from getting back here, but
599 // sometimes paranoia is good.
600 did_trans_retry = true;
601
602 // We wait for the thread to transition to a more usable state.
603 for (int i = 1; i <= SuspendRetryCount; i++) {
604 // We used to do an "os::yield_all(i)" call here with the intention
605 // that yielding would increase on each retry. However, the parameter
606 // is ignored on Linux which means the yield didn't scale up. Waiting
607 // on the SR_lock below provides a much more predictable scale up for
608 // the delay. It also provides a simple/direct point to check for any
609 // safepoint requests from the VMThread
610
611 // temporarily drops SR_lock while doing wait with safepoint check
612 // (if we're a JavaThread - the WatcherThread can also call this)
613 // and increase delay with each retry
614 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
615
616 // check the actual thread state instead of what we saved above
617 if (thread_state() != _thread_in_native_trans) {
618 // the thread has transitioned to another thread state so
619 // try all the checks (except this one) one more time.
620 do_trans_retry = true;
621 break;
622 }
623 } // end retry loop
624
625
626 }
627 } while (do_trans_retry);
628
629 *bits |= 0x00000010;
630 return false;
631 }
632
633 // Wait for an external suspend request to complete (or be cancelled).
634 // Returns true if the thread is externally suspended and false otherwise.
635 //
636 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
637 uint32_t *bits) {
638 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
639 false /* !called_by_wait */, bits);
640
641 // local flag copies to minimize SR_lock hold time
642 bool is_suspended;
643 bool pending;
644 uint32_t reset_bits;
645
646 // set a marker so is_ext_suspend_completed() knows we are the caller
647 *bits |= 0x00010000;
648
649 // We use reset_bits to reinitialize the bits value at the top of
650 // each retry loop. This allows the caller to make use of any
651 // unused bits for their own marking purposes.
652 reset_bits = *bits;
653
654 {
655 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
656 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
657 delay, bits);
658 pending = is_external_suspend();
659 }
660 // must release SR_lock to allow suspension to complete
661
662 if (!pending) {
663 // A cancelled suspend request is the only false return from
664 // is_ext_suspend_completed() that keeps us from entering the
665 // retry loop.
666 *bits |= 0x00020000;
667 return false;
668 }
669
670 if (is_suspended) {
671 *bits |= 0x00040000;
672 return true;
673 }
674
675 for (int i = 1; i <= retries; i++) {
676 *bits = reset_bits; // reinit to only track last retry
677
678 // We used to do an "os::yield_all(i)" call here with the intention
679 // that yielding would increase on each retry. However, the parameter
680 // is ignored on Linux which means the yield didn't scale up. Waiting
681 // on the SR_lock below provides a much more predictable scale up for
682 // the delay. It also provides a simple/direct point to check for any
683 // safepoint requests from the VMThread
684
685 {
686 MutexLocker ml(SR_lock());
687 // wait with safepoint check (if we're a JavaThread - the WatcherThread
688 // can also call this) and increase delay with each retry
689 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
690
691 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
692 delay, bits);
693
694 // It is possible for the external suspend request to be cancelled
695 // (by a resume) before the actual suspend operation is completed.
696 // Refresh our local copy to see if we still need to wait.
697 pending = is_external_suspend();
698 }
699
700 if (!pending) {
701 // A cancelled suspend request is the only false return from
702 // is_ext_suspend_completed() that keeps us from staying in the
703 // retry loop.
704 *bits |= 0x00080000;
705 return false;
706 }
707
708 if (is_suspended) {
709 *bits |= 0x00100000;
710 return true;
711 }
712 } // end retry loop
713
714 // thread did not suspend after all our retries
715 *bits |= 0x00200000;
716 return false;
717 }
718
719 #ifndef PRODUCT
720 void JavaThread::record_jump(address target, address instr, const char* file,
721 int line) {
722
723 // This should not need to be atomic as the only way for simultaneous
724 // updates is via interrupts. Even then this should be rare or non-existent
725 // and we don't care that much anyway.
726
727 int index = _jmp_ring_index;
728 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
729 _jmp_ring[index]._target = (intptr_t) target;
730 _jmp_ring[index]._instruction = (intptr_t) instr;
731 _jmp_ring[index]._file = file;
732 _jmp_ring[index]._line = line;
733 }
734 #endif // PRODUCT
735
736 // Called by flat profiler
737 // Callers have already called wait_for_ext_suspend_completion
738 // The assertion for that is currently too complex to put here:
739 bool JavaThread::profile_last_Java_frame(frame* _fr) {
740 bool gotframe = false;
741 // self suspension saves needed state.
742 if (has_last_Java_frame() && _anchor.walkable()) {
743 *_fr = pd_last_frame();
744 gotframe = true;
745 }
746 return gotframe;
747 }
748
749 void Thread::interrupt(Thread* thread) {
750 debug_only(check_for_dangling_thread_pointer(thread);)
751 os::interrupt(thread);
752 }
753
754 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
755 debug_only(check_for_dangling_thread_pointer(thread);)
756 // Note: If clear_interrupted==false, this simply fetches and
757 // returns the value of the field osthread()->interrupted().
758 return os::is_interrupted(thread, clear_interrupted);
759 }
760
761
762 // GC Support
763 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
764 jint thread_parity = _oops_do_parity;
765 if (thread_parity != strong_roots_parity) {
766 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
767 if (res == thread_parity) {
768 return true;
769 } else {
770 guarantee(res == strong_roots_parity, "Or else what?");
771 return false;
772 }
773 }
774 return false;
775 }
776
777 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
778 active_handles()->oops_do(f);
779 // Do oop for ThreadShadow
780 f->do_oop((oop*)&_pending_exception);
781 handle_area()->oops_do(f);
782 }
783
784 void Thread::nmethods_do(CodeBlobClosure* cf) {
785 // no nmethods in a generic thread...
786 }
787
788 void Thread::metadata_handles_do(void f(Metadata*)) {
789 // Only walk the Handles in Thread.
790 if (metadata_handles() != NULL) {
791 for (int i = 0; i< metadata_handles()->length(); i++) {
792 f(metadata_handles()->at(i));
793 }
794 }
795 }
796
797 void Thread::print_on(outputStream* st) const {
798 // get_priority assumes osthread initialized
799 if (osthread() != NULL) {
800 int os_prio;
801 if (os::get_native_priority(this, &os_prio) == OS_OK) {
802 st->print("os_prio=%d ", os_prio);
803 }
804 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
805 ext().print_on(st);
806 osthread()->print_on(st);
807 }
808 debug_only(if (WizardMode) print_owned_locks_on(st);)
809 }
810
811 // Thread::print_on_error() is called by fatal error handler. Don't use
812 // any lock or allocate memory.
813 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
814 if (is_VM_thread()) st->print("VMThread");
815 else if (is_Compiler_thread()) st->print("CompilerThread");
816 else if (is_Java_thread()) st->print("JavaThread");
817 else if (is_GC_task_thread()) st->print("GCTaskThread");
818 else if (is_Watcher_thread()) st->print("WatcherThread");
819 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
820 else st->print("Thread");
821
822 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
823 p2i(_stack_base - _stack_size), p2i(_stack_base));
824
825 if (osthread()) {
826 st->print(" [id=%d]", osthread()->thread_id());
827 }
828 }
829
830 #ifdef ASSERT
831 void Thread::print_owned_locks_on(outputStream* st) const {
832 Monitor *cur = _owned_locks;
833 if (cur == NULL) {
834 st->print(" (no locks) ");
835 } else {
836 st->print_cr(" Locks owned:");
837 while (cur) {
838 cur->print_on(st);
839 cur = cur->next();
840 }
841 }
842 }
843
844 static int ref_use_count = 0;
845
846 bool Thread::owns_locks_but_compiled_lock() const {
847 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
848 if (cur != Compile_lock) return true;
849 }
850 return false;
851 }
852
853
854 #endif
855
856 #ifndef PRODUCT
857
858 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
859 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
860 // no threads which allow_vm_block's are held
861 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
862 // Check if current thread is allowed to block at a safepoint
863 if (!(_allow_safepoint_count == 0)) {
864 fatal("Possible safepoint reached by thread that does not allow it");
865 }
866 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
867 fatal("LEAF method calling lock?");
868 }
869
870 #ifdef ASSERT
871 if (potential_vm_operation && is_Java_thread()
872 && !Universe::is_bootstrapping()) {
873 // Make sure we do not hold any locks that the VM thread also uses.
874 // This could potentially lead to deadlocks
875 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
876 // Threads_lock is special, since the safepoint synchronization will not start before this is
877 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
878 // since it is used to transfer control between JavaThreads and the VMThread
879 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
880 if ((cur->allow_vm_block() &&
881 cur != Threads_lock &&
882 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
883 cur != VMOperationRequest_lock &&
884 cur != VMOperationQueue_lock) ||
885 cur->rank() == Mutex::special) {
886 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
887 }
888 }
889 }
890
891 if (GCALotAtAllSafepoints) {
892 // We could enter a safepoint here and thus have a gc
893 InterfaceSupport::check_gc_alot();
894 }
895 #endif
896 }
897 #endif
898
899 bool Thread::is_in_stack(address adr) const {
900 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
901 address end = os::current_stack_pointer();
902 // Allow non Java threads to call this without stack_base
903 if (_stack_base == NULL) return true;
904 if (stack_base() >= adr && adr >= end) return true;
905
906 return false;
907 }
908
909
910 bool Thread::is_in_usable_stack(address adr) const {
911 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
912 size_t usable_stack_size = _stack_size - stack_guard_size;
913
914 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
915 }
916
917
918 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
919 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
920 // used for compilation in the future. If that change is made, the need for these methods
921 // should be revisited, and they should be removed if possible.
922
923 bool Thread::is_lock_owned(address adr) const {
924 return on_local_stack(adr);
925 }
926
927 bool Thread::set_as_starting_thread() {
928 // NOTE: this must be called inside the main thread.
929 return os::create_main_thread((JavaThread*)this);
930 }
931
932 static void initialize_class(Symbol* class_name, TRAPS) {
933 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
934 InstanceKlass::cast(klass)->initialize(CHECK);
935 }
936
937
938 // Creates the initial ThreadGroup
939 static Handle create_initial_thread_group(TRAPS) {
940 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
941 instanceKlassHandle klass (THREAD, k);
942
943 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
944 {
945 JavaValue result(T_VOID);
946 JavaCalls::call_special(&result,
947 system_instance,
948 klass,
949 vmSymbols::object_initializer_name(),
950 vmSymbols::void_method_signature(),
951 CHECK_NH);
952 }
953 Universe::set_system_thread_group(system_instance());
954
955 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
956 {
957 JavaValue result(T_VOID);
958 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
959 JavaCalls::call_special(&result,
960 main_instance,
961 klass,
962 vmSymbols::object_initializer_name(),
963 vmSymbols::threadgroup_string_void_signature(),
964 system_instance,
965 string,
966 CHECK_NH);
967 }
968 return main_instance;
969 }
970
971 // Creates the initial Thread
972 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
973 TRAPS) {
974 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
975 instanceKlassHandle klass (THREAD, k);
976 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
977
978 java_lang_Thread::set_thread(thread_oop(), thread);
979 java_lang_Thread::set_priority(thread_oop(), NormPriority);
980 thread->set_threadObj(thread_oop());
981
982 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
983
984 JavaValue result(T_VOID);
985 JavaCalls::call_special(&result, thread_oop,
986 klass,
987 vmSymbols::object_initializer_name(),
988 vmSymbols::threadgroup_string_void_signature(),
989 thread_group,
990 string,
991 CHECK_NULL);
992 return thread_oop();
993 }
994
995 static void call_initializeSystemClass(TRAPS) {
996 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
997 instanceKlassHandle klass (THREAD, k);
998
999 JavaValue result(T_VOID);
1000 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1001 vmSymbols::void_method_signature(), CHECK);
1002 }
1003
1004 char java_runtime_name[128] = "";
1005 char java_runtime_version[128] = "";
1006
1007 // extract the JRE name from sun.misc.Version.java_runtime_name
1008 static const char* get_java_runtime_name(TRAPS) {
1009 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1010 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1011 fieldDescriptor fd;
1012 bool found = k != NULL &&
1013 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1014 vmSymbols::string_signature(), &fd);
1015 if (found) {
1016 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1017 if (name_oop == NULL) {
1018 return NULL;
1019 }
1020 const char* name = java_lang_String::as_utf8_string(name_oop,
1021 java_runtime_name,
1022 sizeof(java_runtime_name));
1023 return name;
1024 } else {
1025 return NULL;
1026 }
1027 }
1028
1029 // extract the JRE version from sun.misc.Version.java_runtime_version
1030 static const char* get_java_runtime_version(TRAPS) {
1031 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1032 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1033 fieldDescriptor fd;
1034 bool found = k != NULL &&
1035 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1036 vmSymbols::string_signature(), &fd);
1037 if (found) {
1038 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1039 if (name_oop == NULL) {
1040 return NULL;
1041 }
1042 const char* name = java_lang_String::as_utf8_string(name_oop,
1043 java_runtime_version,
1044 sizeof(java_runtime_version));
1045 return name;
1046 } else {
1047 return NULL;
1048 }
1049 }
1050
1051 // General purpose hook into Java code, run once when the VM is initialized.
1052 // The Java library method itself may be changed independently from the VM.
1053 static void call_postVMInitHook(TRAPS) {
1054 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1055 instanceKlassHandle klass (THREAD, k);
1056 if (klass.not_null()) {
1057 JavaValue result(T_VOID);
1058 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1059 vmSymbols::void_method_signature(),
1060 CHECK);
1061 }
1062 }
1063
1064 static void reset_vm_info_property(TRAPS) {
1065 // the vm info string
1066 ResourceMark rm(THREAD);
1067 const char *vm_info = VM_Version::vm_info_string();
1068
1069 // java.lang.System class
1070 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1071 instanceKlassHandle klass (THREAD, k);
1072
1073 // setProperty arguments
1074 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1075 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1076
1077 // return value
1078 JavaValue r(T_OBJECT);
1079
1080 // public static String setProperty(String key, String value);
1081 JavaCalls::call_static(&r,
1082 klass,
1083 vmSymbols::setProperty_name(),
1084 vmSymbols::string_string_string_signature(),
1085 key_str,
1086 value_str,
1087 CHECK);
1088 }
1089
1090
1091 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1092 bool daemon, TRAPS) {
1093 assert(thread_group.not_null(), "thread group should be specified");
1094 assert(threadObj() == NULL, "should only create Java thread object once");
1095
1096 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1097 instanceKlassHandle klass (THREAD, k);
1098 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1099
1100 java_lang_Thread::set_thread(thread_oop(), this);
1101 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1102 set_threadObj(thread_oop());
1103
1104 JavaValue result(T_VOID);
1105 if (thread_name != NULL) {
1106 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1107 // Thread gets assigned specified name and null target
1108 JavaCalls::call_special(&result,
1109 thread_oop,
1110 klass,
1111 vmSymbols::object_initializer_name(),
1112 vmSymbols::threadgroup_string_void_signature(),
1113 thread_group, // Argument 1
1114 name, // Argument 2
1115 THREAD);
1116 } else {
1117 // Thread gets assigned name "Thread-nnn" and null target
1118 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1119 JavaCalls::call_special(&result,
1120 thread_oop,
1121 klass,
1122 vmSymbols::object_initializer_name(),
1123 vmSymbols::threadgroup_runnable_void_signature(),
1124 thread_group, // Argument 1
1125 Handle(), // Argument 2
1126 THREAD);
1127 }
1128
1129
1130 if (daemon) {
1131 java_lang_Thread::set_daemon(thread_oop());
1132 }
1133
1134 if (HAS_PENDING_EXCEPTION) {
1135 return;
1136 }
1137
1138 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1139 Handle threadObj(THREAD, this->threadObj());
1140
1141 JavaCalls::call_special(&result,
1142 thread_group,
1143 group,
1144 vmSymbols::add_method_name(),
1145 vmSymbols::thread_void_signature(),
1146 threadObj, // Arg 1
1147 THREAD);
1148 }
1149
1150 // NamedThread -- non-JavaThread subclasses with multiple
1151 // uniquely named instances should derive from this.
1152 NamedThread::NamedThread() : Thread() {
1153 _name = NULL;
1154 _processed_thread = NULL;
1155 _gc_id = GCId::undefined();
1156 }
1157
1158 NamedThread::~NamedThread() {
1159 if (_name != NULL) {
1160 FREE_C_HEAP_ARRAY(char, _name);
1161 _name = NULL;
1162 }
1163 }
1164
1165 void NamedThread::set_name(const char* format, ...) {
1166 guarantee(_name == NULL, "Only get to set name once.");
1167 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1168 guarantee(_name != NULL, "alloc failure");
1169 va_list ap;
1170 va_start(ap, format);
1171 jio_vsnprintf(_name, max_name_len, format, ap);
1172 va_end(ap);
1173 }
1174
1175 void NamedThread::initialize_named_thread() {
1176 set_native_thread_name(name());
1177 }
1178
1179 void NamedThread::print_on(outputStream* st) const {
1180 st->print("\"%s\" ", name());
1181 Thread::print_on(st);
1182 st->cr();
1183 }
1184
1185
1186 // ======= WatcherThread ========
1187
1188 // The watcher thread exists to simulate timer interrupts. It should
1189 // be replaced by an abstraction over whatever native support for
1190 // timer interrupts exists on the platform.
1191
1192 WatcherThread* WatcherThread::_watcher_thread = NULL;
1193 bool WatcherThread::_startable = false;
1194 volatile bool WatcherThread::_should_terminate = false;
1195
1196 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1197 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1198 if (os::create_thread(this, os::watcher_thread)) {
1199 _watcher_thread = this;
1200
1201 // Set the watcher thread to the highest OS priority which should not be
1202 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1203 // is created. The only normal thread using this priority is the reference
1204 // handler thread, which runs for very short intervals only.
1205 // If the VMThread's priority is not lower than the WatcherThread profiling
1206 // will be inaccurate.
1207 os::set_priority(this, MaxPriority);
1208 if (!DisableStartThread) {
1209 os::start_thread(this);
1210 }
1211 }
1212 }
1213
1214 int WatcherThread::sleep() const {
1215 // The WatcherThread does not participate in the safepoint protocol
1216 // for the PeriodicTask_lock because it is not a JavaThread.
1217 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1218
1219 if (_should_terminate) {
1220 // check for termination before we do any housekeeping or wait
1221 return 0; // we did not sleep.
1222 }
1223
1224 // remaining will be zero if there are no tasks,
1225 // causing the WatcherThread to sleep until a task is
1226 // enrolled
1227 int remaining = PeriodicTask::time_to_wait();
1228 int time_slept = 0;
1229
1230 // we expect this to timeout - we only ever get unparked when
1231 // we should terminate or when a new task has been enrolled
1232 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1233
1234 jlong time_before_loop = os::javaTimeNanos();
1235
1236 while (true) {
1237 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1238 remaining);
1239 jlong now = os::javaTimeNanos();
1240
1241 if (remaining == 0) {
1242 // if we didn't have any tasks we could have waited for a long time
1243 // consider the time_slept zero and reset time_before_loop
1244 time_slept = 0;
1245 time_before_loop = now;
1246 } else {
1247 // need to recalculate since we might have new tasks in _tasks
1248 time_slept = (int) ((now - time_before_loop) / 1000000);
1249 }
1250
1251 // Change to task list or spurious wakeup of some kind
1252 if (timedout || _should_terminate) {
1253 break;
1254 }
1255
1256 remaining = PeriodicTask::time_to_wait();
1257 if (remaining == 0) {
1258 // Last task was just disenrolled so loop around and wait until
1259 // another task gets enrolled
1260 continue;
1261 }
1262
1263 remaining -= time_slept;
1264 if (remaining <= 0) {
1265 break;
1266 }
1267 }
1268
1269 return time_slept;
1270 }
1271
1272 void WatcherThread::run() {
1273 assert(this == watcher_thread(), "just checking");
1274
1275 this->record_stack_base_and_size();
1276 this->set_native_thread_name(this->name());
1277 this->set_active_handles(JNIHandleBlock::allocate_block());
1278 while (true) {
1279 assert(watcher_thread() == Thread::current(), "thread consistency check");
1280 assert(watcher_thread() == this, "thread consistency check");
1281
1282 // Calculate how long it'll be until the next PeriodicTask work
1283 // should be done, and sleep that amount of time.
1284 int time_waited = sleep();
1285
1286 if (is_error_reported()) {
1287 // A fatal error has happened, the error handler(VMError::report_and_die)
1288 // should abort JVM after creating an error log file. However in some
1289 // rare cases, the error handler itself might deadlock. Here we try to
1290 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1291 //
1292 // This code is in WatcherThread because WatcherThread wakes up
1293 // periodically so the fatal error handler doesn't need to do anything;
1294 // also because the WatcherThread is less likely to crash than other
1295 // threads.
1296
1297 for (;;) {
1298 if (!ShowMessageBoxOnError
1299 && (OnError == NULL || OnError[0] == '\0')
1300 && Arguments::abort_hook() == NULL) {
1301 os::sleep(this, (jlong)ErrorLogTimeout * 1000, false); // in seconds
1302 fdStream err(defaultStream::output_fd());
1303 err.print_raw_cr("# [ timer expired, abort... ]");
1304 // skip atexit/vm_exit/vm_abort hooks
1305 os::die();
1306 }
1307
1308 // Wake up 5 seconds later, the fatal handler may reset OnError or
1309 // ShowMessageBoxOnError when it is ready to abort.
1310 os::sleep(this, 5 * 1000, false);
1311 }
1312 }
1313
1314 if (_should_terminate) {
1315 // check for termination before posting the next tick
1316 break;
1317 }
1318
1319 PeriodicTask::real_time_tick(time_waited);
1320 }
1321
1322 // Signal that it is terminated
1323 {
1324 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1325 _watcher_thread = NULL;
1326 Terminator_lock->notify();
1327 }
1328 }
1329
1330 void WatcherThread::start() {
1331 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1332
1333 if (watcher_thread() == NULL && _startable) {
1334 _should_terminate = false;
1335 // Create the single instance of WatcherThread
1336 new WatcherThread();
1337 }
1338 }
1339
1340 void WatcherThread::make_startable() {
1341 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1342 _startable = true;
1343 }
1344
1345 void WatcherThread::stop() {
1346 {
1347 // Follow normal safepoint aware lock enter protocol since the
1348 // WatcherThread is stopped by another JavaThread.
1349 MutexLocker ml(PeriodicTask_lock);
1350 _should_terminate = true;
1351
1352 WatcherThread* watcher = watcher_thread();
1353 if (watcher != NULL) {
1354 // unpark the WatcherThread so it can see that it should terminate
1355 watcher->unpark();
1356 }
1357 }
1358
1359 MutexLocker mu(Terminator_lock);
1360
1361 while (watcher_thread() != NULL) {
1362 // This wait should make safepoint checks, wait without a timeout,
1363 // and wait as a suspend-equivalent condition.
1364 //
1365 // Note: If the FlatProfiler is running, then this thread is waiting
1366 // for the WatcherThread to terminate and the WatcherThread, via the
1367 // FlatProfiler task, is waiting for the external suspend request on
1368 // this thread to complete. wait_for_ext_suspend_completion() will
1369 // eventually timeout, but that takes time. Making this wait a
1370 // suspend-equivalent condition solves that timeout problem.
1371 //
1372 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1373 Mutex::_as_suspend_equivalent_flag);
1374 }
1375 }
1376
1377 void WatcherThread::unpark() {
1378 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1379 PeriodicTask_lock->notify();
1380 }
1381
1382 void WatcherThread::print_on(outputStream* st) const {
1383 st->print("\"%s\" ", name());
1384 Thread::print_on(st);
1385 st->cr();
1386 }
1387
1388 // ======= JavaThread ========
1389
1390 #if INCLUDE_JVMCI
1391
1392 jlong* JavaThread::_jvmci_old_thread_counters;
1393
1394 bool jvmci_counters_include(JavaThread* thread) {
1395 oop threadObj = thread->threadObj();
1396 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1397 }
1398
1399 void JavaThread::collect_counters(typeArrayOop array) {
1400 if (JVMCICounterSize > 0) {
1401 MutexLocker tl(Threads_lock);
1402 for (int i = 0; i < array->length(); i++) {
1403 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1404 }
1405 for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) {
1406 if (jvmci_counters_include(tp)) {
1407 for (int i = 0; i < array->length(); i++) {
1408 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1409 }
1410 }
1411 }
1412 }
1413 }
1414
1415 #endif // INCLUDE_JVMCI
1416
1417 // A JavaThread is a normal Java thread
1418
1419 void JavaThread::initialize() {
1420 // Initialize fields
1421
1422 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1423 set_claimed_par_id(UINT_MAX);
1424
1425 set_saved_exception_pc(NULL);
1426 set_threadObj(NULL);
1427 _anchor.clear();
1428 set_entry_point(NULL);
1429 set_jni_functions(jni_functions());
1430 set_callee_target(NULL);
1431 set_vm_result(NULL);
1432 set_vm_result_2(NULL);
1433 set_vframe_array_head(NULL);
1434 set_vframe_array_last(NULL);
1435 set_deferred_locals(NULL);
1436 set_deopt_mark(NULL);
1437 set_deopt_nmethod(NULL);
1438 clear_must_deopt_id();
1439 set_monitor_chunks(NULL);
1440 set_next(NULL);
1441 set_thread_state(_thread_new);
1442 _terminated = _not_terminated;
1443 _privileged_stack_top = NULL;
1444 _array_for_gc = NULL;
1445 _suspend_equivalent = false;
1446 _in_deopt_handler = 0;
1447 _doing_unsafe_access = false;
1448 _stack_guard_state = stack_guard_unused;
1449 #if INCLUDE_JVMCI
1450 _pending_monitorenter = false;
1451 _pending_deoptimization = -1;
1452 _pending_failed_speculation = NULL;
1453 _pending_transfer_to_interpreter = false;
1454 _jvmci._alternate_call_target = NULL;
1455 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1456 if (JVMCICounterSize > 0) {
1457 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1458 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1459 } else {
1460 _jvmci_counters = NULL;
1461 }
1462 #endif // INCLUDE_JVMCI
1463 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1464 _exception_pc = 0;
1465 _exception_handler_pc = 0;
1466 _is_method_handle_return = 0;
1467 _jvmti_thread_state= NULL;
1468 _should_post_on_exceptions_flag = JNI_FALSE;
1469 _jvmti_get_loaded_classes_closure = NULL;
1470 _interp_only_mode = 0;
1471 _special_runtime_exit_condition = _no_async_condition;
1472 _pending_async_exception = NULL;
1473 _thread_stat = NULL;
1474 _thread_stat = new ThreadStatistics();
1475 _blocked_on_compilation = false;
1476 _jni_active_critical = 0;
1477 _pending_jni_exception_check_fn = NULL;
1478 _do_not_unlock_if_synchronized = false;
1479 _cached_monitor_info = NULL;
1480 _parker = Parker::Allocate(this);
1481
1482 #ifndef PRODUCT
1483 _jmp_ring_index = 0;
1484 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1485 record_jump(NULL, NULL, NULL, 0);
1486 }
1487 #endif // PRODUCT
1488
1489 set_thread_profiler(NULL);
1490 if (FlatProfiler::is_active()) {
1491 // This is where we would decide to either give each thread it's own profiler
1492 // or use one global one from FlatProfiler,
1493 // or up to some count of the number of profiled threads, etc.
1494 ThreadProfiler* pp = new ThreadProfiler();
1495 pp->engage();
1496 set_thread_profiler(pp);
1497 }
1498
1499 // Setup safepoint state info for this thread
1500 ThreadSafepointState::create(this);
1501
1502 debug_only(_java_call_counter = 0);
1503
1504 // JVMTI PopFrame support
1505 _popframe_condition = popframe_inactive;
1506 _popframe_preserved_args = NULL;
1507 _popframe_preserved_args_size = 0;
1508 _frames_to_pop_failed_realloc = 0;
1509
1510 pd_initialize();
1511 }
1512
1513 #if INCLUDE_ALL_GCS
1514 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1515 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1516 #endif // INCLUDE_ALL_GCS
1517
1518 JavaThread::JavaThread(bool is_attaching_via_jni) :
1519 Thread()
1520 #if INCLUDE_ALL_GCS
1521 , _satb_mark_queue(&_satb_mark_queue_set),
1522 _dirty_card_queue(&_dirty_card_queue_set)
1523 #endif // INCLUDE_ALL_GCS
1524 {
1525 initialize();
1526 if (is_attaching_via_jni) {
1527 _jni_attach_state = _attaching_via_jni;
1528 } else {
1529 _jni_attach_state = _not_attaching_via_jni;
1530 }
1531 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1532 }
1533
1534 bool JavaThread::reguard_stack(address cur_sp) {
1535 if (_stack_guard_state != stack_guard_yellow_disabled) {
1536 return true; // Stack already guarded or guard pages not needed.
1537 }
1538
1539 if (register_stack_overflow()) {
1540 // For those architectures which have separate register and
1541 // memory stacks, we must check the register stack to see if
1542 // it has overflowed.
1543 return false;
1544 }
1545
1546 // Java code never executes within the yellow zone: the latter is only
1547 // there to provoke an exception during stack banging. If java code
1548 // is executing there, either StackShadowPages should be larger, or
1549 // some exception code in c1, c2 or the interpreter isn't unwinding
1550 // when it should.
1551 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1552
1553 enable_stack_yellow_zone();
1554 return true;
1555 }
1556
1557 bool JavaThread::reguard_stack(void) {
1558 return reguard_stack(os::current_stack_pointer());
1559 }
1560
1561
1562 void JavaThread::block_if_vm_exited() {
1563 if (_terminated == _vm_exited) {
1564 // _vm_exited is set at safepoint, and Threads_lock is never released
1565 // we will block here forever
1566 Threads_lock->lock_without_safepoint_check();
1567 ShouldNotReachHere();
1568 }
1569 }
1570
1571
1572 // Remove this ifdef when C1 is ported to the compiler interface.
1573 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1574 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1575
1576 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1577 Thread()
1578 #if INCLUDE_ALL_GCS
1579 , _satb_mark_queue(&_satb_mark_queue_set),
1580 _dirty_card_queue(&_dirty_card_queue_set)
1581 #endif // INCLUDE_ALL_GCS
1582 {
1583 initialize();
1584 _jni_attach_state = _not_attaching_via_jni;
1585 set_entry_point(entry_point);
1586 // Create the native thread itself.
1587 // %note runtime_23
1588 os::ThreadType thr_type = os::java_thread;
1589 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1590 os::java_thread;
1591 os::create_thread(this, thr_type, stack_sz);
1592 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1593 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1594 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1595 // the exception consists of creating the exception object & initializing it, initialization
1596 // will leave the VM via a JavaCall and then all locks must be unlocked).
1597 //
1598 // The thread is still suspended when we reach here. Thread must be explicit started
1599 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1600 // by calling Threads:add. The reason why this is not done here, is because the thread
1601 // object must be fully initialized (take a look at JVM_Start)
1602 }
1603
1604 JavaThread::~JavaThread() {
1605
1606 // JSR166 -- return the parker to the free list
1607 Parker::Release(_parker);
1608 _parker = NULL;
1609
1610 // Free any remaining previous UnrollBlock
1611 vframeArray* old_array = vframe_array_last();
1612
1613 if (old_array != NULL) {
1614 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1615 old_array->set_unroll_block(NULL);
1616 delete old_info;
1617 delete old_array;
1618 }
1619
1620 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1621 if (deferred != NULL) {
1622 // This can only happen if thread is destroyed before deoptimization occurs.
1623 assert(deferred->length() != 0, "empty array!");
1624 do {
1625 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1626 deferred->remove_at(0);
1627 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1628 delete dlv;
1629 } while (deferred->length() != 0);
1630 delete deferred;
1631 }
1632
1633 // All Java related clean up happens in exit
1634 ThreadSafepointState::destroy(this);
1635 if (_thread_profiler != NULL) delete _thread_profiler;
1636 if (_thread_stat != NULL) delete _thread_stat;
1637
1638 #if INCLUDE_JVMCI
1639 if (JVMCICounterSize > 0) {
1640 if (jvmci_counters_include(this)) {
1641 for (int i = 0; i < JVMCICounterSize; i++) {
1642 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1643 }
1644 }
1645 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1646 }
1647 #endif // INCLUDE_JVMCI
1648 }
1649
1650
1651 // The first routine called by a new Java thread
1652 void JavaThread::run() {
1653 // initialize thread-local alloc buffer related fields
1654 this->initialize_tlab();
1655
1656 // used to test validity of stack trace backs
1657 this->record_base_of_stack_pointer();
1658
1659 // Record real stack base and size.
1660 this->record_stack_base_and_size();
1661
1662 this->create_stack_guard_pages();
1663
1664 this->cache_global_variables();
1665
1666 // Thread is now sufficient initialized to be handled by the safepoint code as being
1667 // in the VM. Change thread state from _thread_new to _thread_in_vm
1668 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1669
1670 assert(JavaThread::current() == this, "sanity check");
1671 assert(!Thread::current()->owns_locks(), "sanity check");
1672
1673 DTRACE_THREAD_PROBE(start, this);
1674
1675 // This operation might block. We call that after all safepoint checks for a new thread has
1676 // been completed.
1677 this->set_active_handles(JNIHandleBlock::allocate_block());
1678
1679 if (JvmtiExport::should_post_thread_life()) {
1680 JvmtiExport::post_thread_start(this);
1681 }
1682
1683 EventThreadStart event;
1684 if (event.should_commit()) {
1685 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1686 event.commit();
1687 }
1688
1689 // We call another function to do the rest so we are sure that the stack addresses used
1690 // from there will be lower than the stack base just computed
1691 thread_main_inner();
1692
1693 // Note, thread is no longer valid at this point!
1694 }
1695
1696
1697 void JavaThread::thread_main_inner() {
1698 assert(JavaThread::current() == this, "sanity check");
1699 assert(this->threadObj() != NULL, "just checking");
1700
1701 // Execute thread entry point unless this thread has a pending exception
1702 // or has been stopped before starting.
1703 // Note: Due to JVM_StopThread we can have pending exceptions already!
1704 if (!this->has_pending_exception() &&
1705 !java_lang_Thread::is_stillborn(this->threadObj())) {
1706 {
1707 ResourceMark rm(this);
1708 this->set_native_thread_name(this->get_thread_name());
1709 }
1710 HandleMark hm(this);
1711 this->entry_point()(this, this);
1712 }
1713
1714 DTRACE_THREAD_PROBE(stop, this);
1715
1716 this->exit(false);
1717 delete this;
1718 }
1719
1720
1721 static void ensure_join(JavaThread* thread) {
1722 // We do not need to grap the Threads_lock, since we are operating on ourself.
1723 Handle threadObj(thread, thread->threadObj());
1724 assert(threadObj.not_null(), "java thread object must exist");
1725 ObjectLocker lock(threadObj, thread);
1726 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1727 thread->clear_pending_exception();
1728 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1729 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1730 // Clear the native thread instance - this makes isAlive return false and allows the join()
1731 // to complete once we've done the notify_all below
1732 java_lang_Thread::set_thread(threadObj(), NULL);
1733 lock.notify_all(thread);
1734 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1735 thread->clear_pending_exception();
1736 }
1737
1738
1739 // For any new cleanup additions, please check to see if they need to be applied to
1740 // cleanup_failed_attach_current_thread as well.
1741 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1742 assert(this == JavaThread::current(), "thread consistency check");
1743
1744 HandleMark hm(this);
1745 Handle uncaught_exception(this, this->pending_exception());
1746 this->clear_pending_exception();
1747 Handle threadObj(this, this->threadObj());
1748 assert(threadObj.not_null(), "Java thread object should be created");
1749
1750 if (get_thread_profiler() != NULL) {
1751 get_thread_profiler()->disengage();
1752 ResourceMark rm;
1753 get_thread_profiler()->print(get_thread_name());
1754 }
1755
1756
1757 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1758 {
1759 EXCEPTION_MARK;
1760
1761 CLEAR_PENDING_EXCEPTION;
1762 }
1763 if (!destroy_vm) {
1764 if (uncaught_exception.not_null()) {
1765 EXCEPTION_MARK;
1766 // Call method Thread.dispatchUncaughtException().
1767 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1768 JavaValue result(T_VOID);
1769 JavaCalls::call_virtual(&result,
1770 threadObj, thread_klass,
1771 vmSymbols::dispatchUncaughtException_name(),
1772 vmSymbols::throwable_void_signature(),
1773 uncaught_exception,
1774 THREAD);
1775 if (HAS_PENDING_EXCEPTION) {
1776 ResourceMark rm(this);
1777 jio_fprintf(defaultStream::error_stream(),
1778 "\nException: %s thrown from the UncaughtExceptionHandler"
1779 " in thread \"%s\"\n",
1780 pending_exception()->klass()->external_name(),
1781 get_thread_name());
1782 CLEAR_PENDING_EXCEPTION;
1783 }
1784 }
1785
1786 // Called before the java thread exit since we want to read info
1787 // from java_lang_Thread object
1788 EventThreadEnd event;
1789 if (event.should_commit()) {
1790 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1791 event.commit();
1792 }
1793
1794 // Call after last event on thread
1795 EVENT_THREAD_EXIT(this);
1796
1797 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1798 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1799 // is deprecated anyhow.
1800 if (!is_Compiler_thread()) {
1801 int count = 3;
1802 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1803 EXCEPTION_MARK;
1804 JavaValue result(T_VOID);
1805 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1806 JavaCalls::call_virtual(&result,
1807 threadObj, thread_klass,
1808 vmSymbols::exit_method_name(),
1809 vmSymbols::void_method_signature(),
1810 THREAD);
1811 CLEAR_PENDING_EXCEPTION;
1812 }
1813 }
1814 // notify JVMTI
1815 if (JvmtiExport::should_post_thread_life()) {
1816 JvmtiExport::post_thread_end(this);
1817 }
1818
1819 // We have notified the agents that we are exiting, before we go on,
1820 // we must check for a pending external suspend request and honor it
1821 // in order to not surprise the thread that made the suspend request.
1822 while (true) {
1823 {
1824 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1825 if (!is_external_suspend()) {
1826 set_terminated(_thread_exiting);
1827 ThreadService::current_thread_exiting(this);
1828 break;
1829 }
1830 // Implied else:
1831 // Things get a little tricky here. We have a pending external
1832 // suspend request, but we are holding the SR_lock so we
1833 // can't just self-suspend. So we temporarily drop the lock
1834 // and then self-suspend.
1835 }
1836
1837 ThreadBlockInVM tbivm(this);
1838 java_suspend_self();
1839
1840 // We're done with this suspend request, but we have to loop around
1841 // and check again. Eventually we will get SR_lock without a pending
1842 // external suspend request and will be able to mark ourselves as
1843 // exiting.
1844 }
1845 // no more external suspends are allowed at this point
1846 } else {
1847 // before_exit() has already posted JVMTI THREAD_END events
1848 }
1849
1850 // Notify waiters on thread object. This has to be done after exit() is called
1851 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1852 // group should have the destroyed bit set before waiters are notified).
1853 ensure_join(this);
1854 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1855
1856 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1857 // held by this thread must be released. The spec does not distinguish
1858 // between JNI-acquired and regular Java monitors. We can only see
1859 // regular Java monitors here if monitor enter-exit matching is broken.
1860 //
1861 // Optionally release any monitors for regular JavaThread exits. This
1862 // is provided as a work around for any bugs in monitor enter-exit
1863 // matching. This can be expensive so it is not enabled by default.
1864 //
1865 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1866 // ObjectSynchronizer::release_monitors_owned_by_thread().
1867 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
1868 // Sanity check even though JNI DetachCurrentThread() would have
1869 // returned JNI_ERR if there was a Java frame. JavaThread exit
1870 // should be done executing Java code by the time we get here.
1871 assert(!this->has_last_Java_frame(),
1872 "should not have a Java frame when detaching or exiting");
1873 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1874 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1875 }
1876
1877 // These things needs to be done while we are still a Java Thread. Make sure that thread
1878 // is in a consistent state, in case GC happens
1879 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1880
1881 if (active_handles() != NULL) {
1882 JNIHandleBlock* block = active_handles();
1883 set_active_handles(NULL);
1884 JNIHandleBlock::release_block(block);
1885 }
1886
1887 if (free_handle_block() != NULL) {
1888 JNIHandleBlock* block = free_handle_block();
1889 set_free_handle_block(NULL);
1890 JNIHandleBlock::release_block(block);
1891 }
1892
1893 // These have to be removed while this is still a valid thread.
1894 remove_stack_guard_pages();
1895
1896 if (UseTLAB) {
1897 tlab().make_parsable(true); // retire TLAB
1898 }
1899
1900 if (JvmtiEnv::environments_might_exist()) {
1901 JvmtiExport::cleanup_thread(this);
1902 }
1903
1904 // We must flush any deferred card marks before removing a thread from
1905 // the list of active threads.
1906 Universe::heap()->flush_deferred_store_barrier(this);
1907 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1908
1909 #if INCLUDE_ALL_GCS
1910 // We must flush the G1-related buffers before removing a thread
1911 // from the list of active threads. We must do this after any deferred
1912 // card marks have been flushed (above) so that any entries that are
1913 // added to the thread's dirty card queue as a result are not lost.
1914 if (UseG1GC) {
1915 flush_barrier_queues();
1916 }
1917 #endif // INCLUDE_ALL_GCS
1918
1919 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1920 Threads::remove(this);
1921 }
1922
1923 #if INCLUDE_ALL_GCS
1924 // Flush G1-related queues.
1925 void JavaThread::flush_barrier_queues() {
1926 satb_mark_queue().flush();
1927 dirty_card_queue().flush();
1928 }
1929
1930 void JavaThread::initialize_queues() {
1931 assert(!SafepointSynchronize::is_at_safepoint(),
1932 "we should not be at a safepoint");
1933
1934 SATBMarkQueue& satb_queue = satb_mark_queue();
1935 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1936 // The SATB queue should have been constructed with its active
1937 // field set to false.
1938 assert(!satb_queue.is_active(), "SATB queue should not be active");
1939 assert(satb_queue.is_empty(), "SATB queue should be empty");
1940 // If we are creating the thread during a marking cycle, we should
1941 // set the active field of the SATB queue to true.
1942 if (satb_queue_set.is_active()) {
1943 satb_queue.set_active(true);
1944 }
1945
1946 DirtyCardQueue& dirty_queue = dirty_card_queue();
1947 // The dirty card queue should have been constructed with its
1948 // active field set to true.
1949 assert(dirty_queue.is_active(), "dirty card queue should be active");
1950 }
1951 #endif // INCLUDE_ALL_GCS
1952
1953 void JavaThread::cleanup_failed_attach_current_thread() {
1954 if (get_thread_profiler() != NULL) {
1955 get_thread_profiler()->disengage();
1956 ResourceMark rm;
1957 get_thread_profiler()->print(get_thread_name());
1958 }
1959
1960 if (active_handles() != NULL) {
1961 JNIHandleBlock* block = active_handles();
1962 set_active_handles(NULL);
1963 JNIHandleBlock::release_block(block);
1964 }
1965
1966 if (free_handle_block() != NULL) {
1967 JNIHandleBlock* block = free_handle_block();
1968 set_free_handle_block(NULL);
1969 JNIHandleBlock::release_block(block);
1970 }
1971
1972 // These have to be removed while this is still a valid thread.
1973 remove_stack_guard_pages();
1974
1975 if (UseTLAB) {
1976 tlab().make_parsable(true); // retire TLAB, if any
1977 }
1978
1979 #if INCLUDE_ALL_GCS
1980 if (UseG1GC) {
1981 flush_barrier_queues();
1982 }
1983 #endif // INCLUDE_ALL_GCS
1984
1985 Threads::remove(this);
1986 delete this;
1987 }
1988
1989
1990
1991
1992 JavaThread* JavaThread::active() {
1993 Thread* thread = Thread::current();
1994 if (thread->is_Java_thread()) {
1995 return (JavaThread*) thread;
1996 } else {
1997 assert(thread->is_VM_thread(), "this must be a vm thread");
1998 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1999 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2000 assert(ret->is_Java_thread(), "must be a Java thread");
2001 return ret;
2002 }
2003 }
2004
2005 bool JavaThread::is_lock_owned(address adr) const {
2006 if (Thread::is_lock_owned(adr)) return true;
2007
2008 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2009 if (chunk->contains(adr)) return true;
2010 }
2011
2012 return false;
2013 }
2014
2015
2016 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2017 chunk->set_next(monitor_chunks());
2018 set_monitor_chunks(chunk);
2019 }
2020
2021 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2022 guarantee(monitor_chunks() != NULL, "must be non empty");
2023 if (monitor_chunks() == chunk) {
2024 set_monitor_chunks(chunk->next());
2025 } else {
2026 MonitorChunk* prev = monitor_chunks();
2027 while (prev->next() != chunk) prev = prev->next();
2028 prev->set_next(chunk->next());
2029 }
2030 }
2031
2032 // JVM support.
2033
2034 // Note: this function shouldn't block if it's called in
2035 // _thread_in_native_trans state (such as from
2036 // check_special_condition_for_native_trans()).
2037 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2038
2039 if (has_last_Java_frame() && has_async_condition()) {
2040 // If we are at a polling page safepoint (not a poll return)
2041 // then we must defer async exception because live registers
2042 // will be clobbered by the exception path. Poll return is
2043 // ok because the call we a returning from already collides
2044 // with exception handling registers and so there is no issue.
2045 // (The exception handling path kills call result registers but
2046 // this is ok since the exception kills the result anyway).
2047
2048 if (is_at_poll_safepoint()) {
2049 // if the code we are returning to has deoptimized we must defer
2050 // the exception otherwise live registers get clobbered on the
2051 // exception path before deoptimization is able to retrieve them.
2052 //
2053 RegisterMap map(this, false);
2054 frame caller_fr = last_frame().sender(&map);
2055 assert(caller_fr.is_compiled_frame(), "what?");
2056 if (caller_fr.is_deoptimized_frame()) {
2057 if (TraceExceptions) {
2058 ResourceMark rm;
2059 tty->print_cr("deferred async exception at compiled safepoint");
2060 }
2061 return;
2062 }
2063 }
2064 }
2065
2066 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2067 if (condition == _no_async_condition) {
2068 // Conditions have changed since has_special_runtime_exit_condition()
2069 // was called:
2070 // - if we were here only because of an external suspend request,
2071 // then that was taken care of above (or cancelled) so we are done
2072 // - if we were here because of another async request, then it has
2073 // been cleared between the has_special_runtime_exit_condition()
2074 // and now so again we are done
2075 return;
2076 }
2077
2078 // Check for pending async. exception
2079 if (_pending_async_exception != NULL) {
2080 // Only overwrite an already pending exception, if it is not a threadDeath.
2081 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2082
2083 // We cannot call Exceptions::_throw(...) here because we cannot block
2084 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2085
2086 if (TraceExceptions) {
2087 ResourceMark rm;
2088 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2089 if (has_last_Java_frame()) {
2090 frame f = last_frame();
2091 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2092 }
2093 tty->print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2094 }
2095 _pending_async_exception = NULL;
2096 clear_has_async_exception();
2097 }
2098 }
2099
2100 if (check_unsafe_error &&
2101 condition == _async_unsafe_access_error && !has_pending_exception()) {
2102 condition = _no_async_condition; // done
2103 switch (thread_state()) {
2104 case _thread_in_vm: {
2105 JavaThread* THREAD = this;
2106 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2107 }
2108 case _thread_in_native: {
2109 ThreadInVMfromNative tiv(this);
2110 JavaThread* THREAD = this;
2111 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2112 }
2113 case _thread_in_Java: {
2114 ThreadInVMfromJava tiv(this);
2115 JavaThread* THREAD = this;
2116 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2117 }
2118 default:
2119 ShouldNotReachHere();
2120 }
2121 }
2122
2123 assert(condition == _no_async_condition || has_pending_exception() ||
2124 (!check_unsafe_error && condition == _async_unsafe_access_error),
2125 "must have handled the async condition, if no exception");
2126 }
2127
2128 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2129 //
2130 // Check for pending external suspend. Internal suspend requests do
2131 // not use handle_special_runtime_exit_condition().
2132 // If JNIEnv proxies are allowed, don't self-suspend if the target
2133 // thread is not the current thread. In older versions of jdbx, jdbx
2134 // threads could call into the VM with another thread's JNIEnv so we
2135 // can be here operating on behalf of a suspended thread (4432884).
2136 bool do_self_suspend = is_external_suspend_with_lock();
2137 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2138 //
2139 // Because thread is external suspended the safepoint code will count
2140 // thread as at a safepoint. This can be odd because we can be here
2141 // as _thread_in_Java which would normally transition to _thread_blocked
2142 // at a safepoint. We would like to mark the thread as _thread_blocked
2143 // before calling java_suspend_self like all other callers of it but
2144 // we must then observe proper safepoint protocol. (We can't leave
2145 // _thread_blocked with a safepoint in progress). However we can be
2146 // here as _thread_in_native_trans so we can't use a normal transition
2147 // constructor/destructor pair because they assert on that type of
2148 // transition. We could do something like:
2149 //
2150 // JavaThreadState state = thread_state();
2151 // set_thread_state(_thread_in_vm);
2152 // {
2153 // ThreadBlockInVM tbivm(this);
2154 // java_suspend_self()
2155 // }
2156 // set_thread_state(_thread_in_vm_trans);
2157 // if (safepoint) block;
2158 // set_thread_state(state);
2159 //
2160 // but that is pretty messy. Instead we just go with the way the
2161 // code has worked before and note that this is the only path to
2162 // java_suspend_self that doesn't put the thread in _thread_blocked
2163 // mode.
2164
2165 frame_anchor()->make_walkable(this);
2166 java_suspend_self();
2167
2168 // We might be here for reasons in addition to the self-suspend request
2169 // so check for other async requests.
2170 }
2171
2172 if (check_asyncs) {
2173 check_and_handle_async_exceptions();
2174 }
2175 }
2176
2177 void JavaThread::send_thread_stop(oop java_throwable) {
2178 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2179 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2180 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2181
2182 // Do not throw asynchronous exceptions against the compiler thread
2183 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2184 if (!can_call_java()) return;
2185
2186 {
2187 // Actually throw the Throwable against the target Thread - however
2188 // only if there is no thread death exception installed already.
2189 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2190 // If the topmost frame is a runtime stub, then we are calling into
2191 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2192 // must deoptimize the caller before continuing, as the compiled exception handler table
2193 // may not be valid
2194 if (has_last_Java_frame()) {
2195 frame f = last_frame();
2196 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2197 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2198 RegisterMap reg_map(this, UseBiasedLocking);
2199 frame compiled_frame = f.sender(®_map);
2200 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2201 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2202 }
2203 }
2204 }
2205
2206 // Set async. pending exception in thread.
2207 set_pending_async_exception(java_throwable);
2208
2209 if (TraceExceptions) {
2210 ResourceMark rm;
2211 tty->print_cr("Pending Async. exception installed of type: %s", _pending_async_exception->klass()->external_name());
2212 }
2213 // for AbortVMOnException flag
2214 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2215 }
2216 }
2217
2218
2219 // Interrupt thread so it will wake up from a potential wait()
2220 Thread::interrupt(this);
2221 }
2222
2223 // External suspension mechanism.
2224 //
2225 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2226 // to any VM_locks and it is at a transition
2227 // Self-suspension will happen on the transition out of the vm.
2228 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2229 //
2230 // Guarantees on return:
2231 // + Target thread will not execute any new bytecode (that's why we need to
2232 // force a safepoint)
2233 // + Target thread will not enter any new monitors
2234 //
2235 void JavaThread::java_suspend() {
2236 { MutexLocker mu(Threads_lock);
2237 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2238 return;
2239 }
2240 }
2241
2242 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2243 if (!is_external_suspend()) {
2244 // a racing resume has cancelled us; bail out now
2245 return;
2246 }
2247
2248 // suspend is done
2249 uint32_t debug_bits = 0;
2250 // Warning: is_ext_suspend_completed() may temporarily drop the
2251 // SR_lock to allow the thread to reach a stable thread state if
2252 // it is currently in a transient thread state.
2253 if (is_ext_suspend_completed(false /* !called_by_wait */,
2254 SuspendRetryDelay, &debug_bits)) {
2255 return;
2256 }
2257 }
2258
2259 VM_ForceSafepoint vm_suspend;
2260 VMThread::execute(&vm_suspend);
2261 }
2262
2263 // Part II of external suspension.
2264 // A JavaThread self suspends when it detects a pending external suspend
2265 // request. This is usually on transitions. It is also done in places
2266 // where continuing to the next transition would surprise the caller,
2267 // e.g., monitor entry.
2268 //
2269 // Returns the number of times that the thread self-suspended.
2270 //
2271 // Note: DO NOT call java_suspend_self() when you just want to block current
2272 // thread. java_suspend_self() is the second stage of cooperative
2273 // suspension for external suspend requests and should only be used
2274 // to complete an external suspend request.
2275 //
2276 int JavaThread::java_suspend_self() {
2277 int ret = 0;
2278
2279 // we are in the process of exiting so don't suspend
2280 if (is_exiting()) {
2281 clear_external_suspend();
2282 return ret;
2283 }
2284
2285 assert(_anchor.walkable() ||
2286 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2287 "must have walkable stack");
2288
2289 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2290
2291 assert(!this->is_ext_suspended(),
2292 "a thread trying to self-suspend should not already be suspended");
2293
2294 if (this->is_suspend_equivalent()) {
2295 // If we are self-suspending as a result of the lifting of a
2296 // suspend equivalent condition, then the suspend_equivalent
2297 // flag is not cleared until we set the ext_suspended flag so
2298 // that wait_for_ext_suspend_completion() returns consistent
2299 // results.
2300 this->clear_suspend_equivalent();
2301 }
2302
2303 // A racing resume may have cancelled us before we grabbed SR_lock
2304 // above. Or another external suspend request could be waiting for us
2305 // by the time we return from SR_lock()->wait(). The thread
2306 // that requested the suspension may already be trying to walk our
2307 // stack and if we return now, we can change the stack out from under
2308 // it. This would be a "bad thing (TM)" and cause the stack walker
2309 // to crash. We stay self-suspended until there are no more pending
2310 // external suspend requests.
2311 while (is_external_suspend()) {
2312 ret++;
2313 this->set_ext_suspended();
2314
2315 // _ext_suspended flag is cleared by java_resume()
2316 while (is_ext_suspended()) {
2317 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2318 }
2319 }
2320
2321 return ret;
2322 }
2323
2324 #ifdef ASSERT
2325 // verify the JavaThread has not yet been published in the Threads::list, and
2326 // hence doesn't need protection from concurrent access at this stage
2327 void JavaThread::verify_not_published() {
2328 if (!Threads_lock->owned_by_self()) {
2329 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2330 assert(!Threads::includes(this),
2331 "java thread shouldn't have been published yet!");
2332 } else {
2333 assert(!Threads::includes(this),
2334 "java thread shouldn't have been published yet!");
2335 }
2336 }
2337 #endif
2338
2339 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2340 // progress or when _suspend_flags is non-zero.
2341 // Current thread needs to self-suspend if there is a suspend request and/or
2342 // block if a safepoint is in progress.
2343 // Async exception ISN'T checked.
2344 // Note only the ThreadInVMfromNative transition can call this function
2345 // directly and when thread state is _thread_in_native_trans
2346 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2347 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2348
2349 JavaThread *curJT = JavaThread::current();
2350 bool do_self_suspend = thread->is_external_suspend();
2351
2352 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2353
2354 // If JNIEnv proxies are allowed, don't self-suspend if the target
2355 // thread is not the current thread. In older versions of jdbx, jdbx
2356 // threads could call into the VM with another thread's JNIEnv so we
2357 // can be here operating on behalf of a suspended thread (4432884).
2358 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2359 JavaThreadState state = thread->thread_state();
2360
2361 // We mark this thread_blocked state as a suspend-equivalent so
2362 // that a caller to is_ext_suspend_completed() won't be confused.
2363 // The suspend-equivalent state is cleared by java_suspend_self().
2364 thread->set_suspend_equivalent();
2365
2366 // If the safepoint code sees the _thread_in_native_trans state, it will
2367 // wait until the thread changes to other thread state. There is no
2368 // guarantee on how soon we can obtain the SR_lock and complete the
2369 // self-suspend request. It would be a bad idea to let safepoint wait for
2370 // too long. Temporarily change the state to _thread_blocked to
2371 // let the VM thread know that this thread is ready for GC. The problem
2372 // of changing thread state is that safepoint could happen just after
2373 // java_suspend_self() returns after being resumed, and VM thread will
2374 // see the _thread_blocked state. We must check for safepoint
2375 // after restoring the state and make sure we won't leave while a safepoint
2376 // is in progress.
2377 thread->set_thread_state(_thread_blocked);
2378 thread->java_suspend_self();
2379 thread->set_thread_state(state);
2380 // Make sure new state is seen by VM thread
2381 if (os::is_MP()) {
2382 if (UseMembar) {
2383 // Force a fence between the write above and read below
2384 OrderAccess::fence();
2385 } else {
2386 // Must use this rather than serialization page in particular on Windows
2387 InterfaceSupport::serialize_memory(thread);
2388 }
2389 }
2390 }
2391
2392 if (SafepointSynchronize::do_call_back()) {
2393 // If we are safepointing, then block the caller which may not be
2394 // the same as the target thread (see above).
2395 SafepointSynchronize::block(curJT);
2396 }
2397
2398 if (thread->is_deopt_suspend()) {
2399 thread->clear_deopt_suspend();
2400 RegisterMap map(thread, false);
2401 frame f = thread->last_frame();
2402 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2403 f = f.sender(&map);
2404 }
2405 if (f.id() == thread->must_deopt_id()) {
2406 thread->clear_must_deopt_id();
2407 f.deoptimize(thread);
2408 } else {
2409 fatal("missed deoptimization!");
2410 }
2411 }
2412 }
2413
2414 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2415 // progress or when _suspend_flags is non-zero.
2416 // Current thread needs to self-suspend if there is a suspend request and/or
2417 // block if a safepoint is in progress.
2418 // Also check for pending async exception (not including unsafe access error).
2419 // Note only the native==>VM/Java barriers can call this function and when
2420 // thread state is _thread_in_native_trans.
2421 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2422 check_safepoint_and_suspend_for_native_trans(thread);
2423
2424 if (thread->has_async_exception()) {
2425 // We are in _thread_in_native_trans state, don't handle unsafe
2426 // access error since that may block.
2427 thread->check_and_handle_async_exceptions(false);
2428 }
2429 }
2430
2431 // This is a variant of the normal
2432 // check_special_condition_for_native_trans with slightly different
2433 // semantics for use by critical native wrappers. It does all the
2434 // normal checks but also performs the transition back into
2435 // thread_in_Java state. This is required so that critical natives
2436 // can potentially block and perform a GC if they are the last thread
2437 // exiting the GC_locker.
2438 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2439 check_special_condition_for_native_trans(thread);
2440
2441 // Finish the transition
2442 thread->set_thread_state(_thread_in_Java);
2443
2444 if (thread->do_critical_native_unlock()) {
2445 ThreadInVMfromJavaNoAsyncException tiv(thread);
2446 GC_locker::unlock_critical(thread);
2447 thread->clear_critical_native_unlock();
2448 }
2449 }
2450
2451 // We need to guarantee the Threads_lock here, since resumes are not
2452 // allowed during safepoint synchronization
2453 // Can only resume from an external suspension
2454 void JavaThread::java_resume() {
2455 assert_locked_or_safepoint(Threads_lock);
2456
2457 // Sanity check: thread is gone, has started exiting or the thread
2458 // was not externally suspended.
2459 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2460 return;
2461 }
2462
2463 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2464
2465 clear_external_suspend();
2466
2467 if (is_ext_suspended()) {
2468 clear_ext_suspended();
2469 SR_lock()->notify_all();
2470 }
2471 }
2472
2473 void JavaThread::create_stack_guard_pages() {
2474 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2475 address low_addr = stack_base() - stack_size();
2476 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2477
2478 int allocate = os::allocate_stack_guard_pages();
2479 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2480
2481 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2482 warning("Attempt to allocate stack guard pages failed.");
2483 return;
2484 }
2485
2486 if (os::guard_memory((char *) low_addr, len)) {
2487 _stack_guard_state = stack_guard_enabled;
2488 } else {
2489 warning("Attempt to protect stack guard pages failed.");
2490 if (os::uncommit_memory((char *) low_addr, len)) {
2491 warning("Attempt to deallocate stack guard pages failed.");
2492 }
2493 }
2494 }
2495
2496 void JavaThread::remove_stack_guard_pages() {
2497 assert(Thread::current() == this, "from different thread");
2498 if (_stack_guard_state == stack_guard_unused) return;
2499 address low_addr = stack_base() - stack_size();
2500 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2501
2502 if (os::allocate_stack_guard_pages()) {
2503 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2504 _stack_guard_state = stack_guard_unused;
2505 } else {
2506 warning("Attempt to deallocate stack guard pages failed.");
2507 }
2508 } else {
2509 if (_stack_guard_state == stack_guard_unused) return;
2510 if (os::unguard_memory((char *) low_addr, len)) {
2511 _stack_guard_state = stack_guard_unused;
2512 } else {
2513 warning("Attempt to unprotect stack guard pages failed.");
2514 }
2515 }
2516 }
2517
2518 void JavaThread::enable_stack_yellow_zone() {
2519 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2520 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2521
2522 // The base notation is from the stacks point of view, growing downward.
2523 // We need to adjust it to work correctly with guard_memory()
2524 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2525
2526 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2527 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2528
2529 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2530 _stack_guard_state = stack_guard_enabled;
2531 } else {
2532 warning("Attempt to guard stack yellow zone failed.");
2533 }
2534 enable_register_stack_guard();
2535 }
2536
2537 void JavaThread::disable_stack_yellow_zone() {
2538 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2539 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2540
2541 // Simply return if called for a thread that does not use guard pages.
2542 if (_stack_guard_state == stack_guard_unused) return;
2543
2544 // The base notation is from the stacks point of view, growing downward.
2545 // We need to adjust it to work correctly with guard_memory()
2546 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2547
2548 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2549 _stack_guard_state = stack_guard_yellow_disabled;
2550 } else {
2551 warning("Attempt to unguard stack yellow zone failed.");
2552 }
2553 disable_register_stack_guard();
2554 }
2555
2556 void JavaThread::enable_stack_red_zone() {
2557 // The base notation is from the stacks point of view, growing downward.
2558 // We need to adjust it to work correctly with guard_memory()
2559 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2560 address base = stack_red_zone_base() - stack_red_zone_size();
2561
2562 guarantee(base < stack_base(), "Error calculating stack red zone");
2563 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2564
2565 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2566 warning("Attempt to guard stack red zone failed.");
2567 }
2568 }
2569
2570 void JavaThread::disable_stack_red_zone() {
2571 // The base notation is from the stacks point of view, growing downward.
2572 // We need to adjust it to work correctly with guard_memory()
2573 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2574 address base = stack_red_zone_base() - stack_red_zone_size();
2575 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2576 warning("Attempt to unguard stack red zone failed.");
2577 }
2578 }
2579
2580 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2581 // ignore is there is no stack
2582 if (!has_last_Java_frame()) return;
2583 // traverse the stack frames. Starts from top frame.
2584 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2585 frame* fr = fst.current();
2586 f(fr, fst.register_map());
2587 }
2588 }
2589
2590
2591 #ifndef PRODUCT
2592 // Deoptimization
2593 // Function for testing deoptimization
2594 void JavaThread::deoptimize() {
2595 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2596 StackFrameStream fst(this, UseBiasedLocking);
2597 bool deopt = false; // Dump stack only if a deopt actually happens.
2598 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2599 // Iterate over all frames in the thread and deoptimize
2600 for (; !fst.is_done(); fst.next()) {
2601 if (fst.current()->can_be_deoptimized()) {
2602
2603 if (only_at) {
2604 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2605 // consists of comma or carriage return separated numbers so
2606 // search for the current bci in that string.
2607 address pc = fst.current()->pc();
2608 nmethod* nm = (nmethod*) fst.current()->cb();
2609 ScopeDesc* sd = nm->scope_desc_at(pc);
2610 char buffer[8];
2611 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2612 size_t len = strlen(buffer);
2613 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2614 while (found != NULL) {
2615 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2616 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2617 // Check that the bci found is bracketed by terminators.
2618 break;
2619 }
2620 found = strstr(found + 1, buffer);
2621 }
2622 if (!found) {
2623 continue;
2624 }
2625 }
2626
2627 if (DebugDeoptimization && !deopt) {
2628 deopt = true; // One-time only print before deopt
2629 tty->print_cr("[BEFORE Deoptimization]");
2630 trace_frames();
2631 trace_stack();
2632 }
2633 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2634 }
2635 }
2636
2637 if (DebugDeoptimization && deopt) {
2638 tty->print_cr("[AFTER Deoptimization]");
2639 trace_frames();
2640 }
2641 }
2642
2643
2644 // Make zombies
2645 void JavaThread::make_zombies() {
2646 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2647 if (fst.current()->can_be_deoptimized()) {
2648 // it is a Java nmethod
2649 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2650 nm->make_not_entrant();
2651 }
2652 }
2653 }
2654 #endif // PRODUCT
2655
2656
2657 void JavaThread::deoptimized_wrt_marked_nmethods() {
2658 if (!has_last_Java_frame()) return;
2659 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2660 StackFrameStream fst(this, UseBiasedLocking);
2661 for (; !fst.is_done(); fst.next()) {
2662 if (fst.current()->should_be_deoptimized()) {
2663 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2664 }
2665 }
2666 }
2667
2668
2669 // If the caller is a NamedThread, then remember, in the current scope,
2670 // the given JavaThread in its _processed_thread field.
2671 class RememberProcessedThread: public StackObj {
2672 NamedThread* _cur_thr;
2673 public:
2674 RememberProcessedThread(JavaThread* jthr) {
2675 Thread* thread = Thread::current();
2676 if (thread->is_Named_thread()) {
2677 _cur_thr = (NamedThread *)thread;
2678 _cur_thr->set_processed_thread(jthr);
2679 } else {
2680 _cur_thr = NULL;
2681 }
2682 }
2683
2684 ~RememberProcessedThread() {
2685 if (_cur_thr) {
2686 _cur_thr->set_processed_thread(NULL);
2687 }
2688 }
2689 };
2690
2691 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2692 // Verify that the deferred card marks have been flushed.
2693 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2694
2695 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2696 // since there may be more than one thread using each ThreadProfiler.
2697
2698 // Traverse the GCHandles
2699 Thread::oops_do(f, cld_f, cf);
2700
2701 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2702
2703 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2704 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2705
2706 if (has_last_Java_frame()) {
2707 // Record JavaThread to GC thread
2708 RememberProcessedThread rpt(this);
2709
2710 // Traverse the privileged stack
2711 if (_privileged_stack_top != NULL) {
2712 _privileged_stack_top->oops_do(f);
2713 }
2714
2715 // traverse the registered growable array
2716 if (_array_for_gc != NULL) {
2717 for (int index = 0; index < _array_for_gc->length(); index++) {
2718 f->do_oop(_array_for_gc->adr_at(index));
2719 }
2720 }
2721
2722 // Traverse the monitor chunks
2723 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2724 chunk->oops_do(f);
2725 }
2726
2727 // Traverse the execution stack
2728 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2729 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2730 }
2731 }
2732
2733 // callee_target is never live across a gc point so NULL it here should
2734 // it still contain a methdOop.
2735
2736 set_callee_target(NULL);
2737
2738 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2739 // If we have deferred set_locals there might be oops waiting to be
2740 // written
2741 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2742 if (list != NULL) {
2743 for (int i = 0; i < list->length(); i++) {
2744 list->at(i)->oops_do(f);
2745 }
2746 }
2747
2748 // Traverse instance variables at the end since the GC may be moving things
2749 // around using this function
2750 f->do_oop((oop*) &_threadObj);
2751 f->do_oop((oop*) &_vm_result);
2752 f->do_oop((oop*) &_exception_oop);
2753 f->do_oop((oop*) &_pending_async_exception);
2754
2755 if (jvmti_thread_state() != NULL) {
2756 jvmti_thread_state()->oops_do(f);
2757 }
2758 }
2759
2760 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2761 Thread::nmethods_do(cf); // (super method is a no-op)
2762
2763 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2764 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2765
2766 if (has_last_Java_frame()) {
2767 // Traverse the execution stack
2768 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2769 fst.current()->nmethods_do(cf);
2770 }
2771 }
2772 }
2773
2774 void JavaThread::metadata_do(void f(Metadata*)) {
2775 if (has_last_Java_frame()) {
2776 // Traverse the execution stack to call f() on the methods in the stack
2777 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2778 fst.current()->metadata_do(f);
2779 }
2780 } else if (is_Compiler_thread()) {
2781 // need to walk ciMetadata in current compile tasks to keep alive.
2782 CompilerThread* ct = (CompilerThread*)this;
2783 if (ct->env() != NULL) {
2784 ct->env()->metadata_do(f);
2785 }
2786 if (ct->task() != NULL) {
2787 ct->task()->metadata_do(f);
2788 }
2789 }
2790 }
2791
2792 // Printing
2793 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2794 switch (_thread_state) {
2795 case _thread_uninitialized: return "_thread_uninitialized";
2796 case _thread_new: return "_thread_new";
2797 case _thread_new_trans: return "_thread_new_trans";
2798 case _thread_in_native: return "_thread_in_native";
2799 case _thread_in_native_trans: return "_thread_in_native_trans";
2800 case _thread_in_vm: return "_thread_in_vm";
2801 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2802 case _thread_in_Java: return "_thread_in_Java";
2803 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2804 case _thread_blocked: return "_thread_blocked";
2805 case _thread_blocked_trans: return "_thread_blocked_trans";
2806 default: return "unknown thread state";
2807 }
2808 }
2809
2810 #ifndef PRODUCT
2811 void JavaThread::print_thread_state_on(outputStream *st) const {
2812 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2813 };
2814 void JavaThread::print_thread_state() const {
2815 print_thread_state_on(tty);
2816 }
2817 #endif // PRODUCT
2818
2819 // Called by Threads::print() for VM_PrintThreads operation
2820 void JavaThread::print_on(outputStream *st) const {
2821 st->print("\"%s\" ", get_thread_name());
2822 oop thread_oop = threadObj();
2823 if (thread_oop != NULL) {
2824 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2825 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2826 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2827 }
2828 Thread::print_on(st);
2829 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2830 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2831 if (thread_oop != NULL) {
2832 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2833 }
2834 #ifndef PRODUCT
2835 print_thread_state_on(st);
2836 _safepoint_state->print_on(st);
2837 #endif // PRODUCT
2838 }
2839
2840 // Called by fatal error handler. The difference between this and
2841 // JavaThread::print() is that we can't grab lock or allocate memory.
2842 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2843 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2844 oop thread_obj = threadObj();
2845 if (thread_obj != NULL) {
2846 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2847 }
2848 st->print(" [");
2849 st->print("%s", _get_thread_state_name(_thread_state));
2850 if (osthread()) {
2851 st->print(", id=%d", osthread()->thread_id());
2852 }
2853 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2854 p2i(_stack_base - _stack_size), p2i(_stack_base));
2855 st->print("]");
2856 return;
2857 }
2858
2859 // Verification
2860
2861 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2862
2863 void JavaThread::verify() {
2864 // Verify oops in the thread.
2865 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2866
2867 // Verify the stack frames.
2868 frames_do(frame_verify);
2869 }
2870
2871 // CR 6300358 (sub-CR 2137150)
2872 // Most callers of this method assume that it can't return NULL but a
2873 // thread may not have a name whilst it is in the process of attaching to
2874 // the VM - see CR 6412693, and there are places where a JavaThread can be
2875 // seen prior to having it's threadObj set (eg JNI attaching threads and
2876 // if vm exit occurs during initialization). These cases can all be accounted
2877 // for such that this method never returns NULL.
2878 const char* JavaThread::get_thread_name() const {
2879 #ifdef ASSERT
2880 // early safepoints can hit while current thread does not yet have TLS
2881 if (!SafepointSynchronize::is_at_safepoint()) {
2882 Thread *cur = Thread::current();
2883 if (!(cur->is_Java_thread() && cur == this)) {
2884 // Current JavaThreads are allowed to get their own name without
2885 // the Threads_lock.
2886 assert_locked_or_safepoint(Threads_lock);
2887 }
2888 }
2889 #endif // ASSERT
2890 return get_thread_name_string();
2891 }
2892
2893 // Returns a non-NULL representation of this thread's name, or a suitable
2894 // descriptive string if there is no set name
2895 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2896 const char* name_str;
2897 oop thread_obj = threadObj();
2898 if (thread_obj != NULL) {
2899 oop name = java_lang_Thread::name(thread_obj);
2900 if (name != NULL) {
2901 if (buf == NULL) {
2902 name_str = java_lang_String::as_utf8_string(name);
2903 } else {
2904 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2905 }
2906 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2907 name_str = "<no-name - thread is attaching>";
2908 } else {
2909 name_str = Thread::name();
2910 }
2911 } else {
2912 name_str = Thread::name();
2913 }
2914 assert(name_str != NULL, "unexpected NULL thread name");
2915 return name_str;
2916 }
2917
2918
2919 const char* JavaThread::get_threadgroup_name() const {
2920 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2921 oop thread_obj = threadObj();
2922 if (thread_obj != NULL) {
2923 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2924 if (thread_group != NULL) {
2925 // ThreadGroup.name can be null
2926 return java_lang_ThreadGroup::name(thread_group);
2927 }
2928 }
2929 return NULL;
2930 }
2931
2932 const char* JavaThread::get_parent_name() const {
2933 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2934 oop thread_obj = threadObj();
2935 if (thread_obj != NULL) {
2936 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2937 if (thread_group != NULL) {
2938 oop parent = java_lang_ThreadGroup::parent(thread_group);
2939 if (parent != NULL) {
2940 // ThreadGroup.name can be null
2941 return java_lang_ThreadGroup::name(parent);
2942 }
2943 }
2944 }
2945 return NULL;
2946 }
2947
2948 ThreadPriority JavaThread::java_priority() const {
2949 oop thr_oop = threadObj();
2950 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2951 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2952 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2953 return priority;
2954 }
2955
2956 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2957
2958 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2959 // Link Java Thread object <-> C++ Thread
2960
2961 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2962 // and put it into a new Handle. The Handle "thread_oop" can then
2963 // be used to pass the C++ thread object to other methods.
2964
2965 // Set the Java level thread object (jthread) field of the
2966 // new thread (a JavaThread *) to C++ thread object using the
2967 // "thread_oop" handle.
2968
2969 // Set the thread field (a JavaThread *) of the
2970 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2971
2972 Handle thread_oop(Thread::current(),
2973 JNIHandles::resolve_non_null(jni_thread));
2974 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2975 "must be initialized");
2976 set_threadObj(thread_oop());
2977 java_lang_Thread::set_thread(thread_oop(), this);
2978
2979 if (prio == NoPriority) {
2980 prio = java_lang_Thread::priority(thread_oop());
2981 assert(prio != NoPriority, "A valid priority should be present");
2982 }
2983
2984 // Push the Java priority down to the native thread; needs Threads_lock
2985 Thread::set_priority(this, prio);
2986
2987 prepare_ext();
2988
2989 // Add the new thread to the Threads list and set it in motion.
2990 // We must have threads lock in order to call Threads::add.
2991 // It is crucial that we do not block before the thread is
2992 // added to the Threads list for if a GC happens, then the java_thread oop
2993 // will not be visited by GC.
2994 Threads::add(this);
2995 }
2996
2997 oop JavaThread::current_park_blocker() {
2998 // Support for JSR-166 locks
2999 oop thread_oop = threadObj();
3000 if (thread_oop != NULL &&
3001 JDK_Version::current().supports_thread_park_blocker()) {
3002 return java_lang_Thread::park_blocker(thread_oop);
3003 }
3004 return NULL;
3005 }
3006
3007
3008 void JavaThread::print_stack_on(outputStream* st) {
3009 if (!has_last_Java_frame()) return;
3010 ResourceMark rm;
3011 HandleMark hm;
3012
3013 RegisterMap reg_map(this);
3014 vframe* start_vf = last_java_vframe(®_map);
3015 int count = 0;
3016 for (vframe* f = start_vf; f; f = f->sender()) {
3017 if (f->is_java_frame()) {
3018 javaVFrame* jvf = javaVFrame::cast(f);
3019 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3020
3021 // Print out lock information
3022 if (JavaMonitorsInStackTrace) {
3023 jvf->print_lock_info_on(st, count);
3024 }
3025 } else {
3026 // Ignore non-Java frames
3027 }
3028
3029 // Bail-out case for too deep stacks
3030 count++;
3031 if (MaxJavaStackTraceDepth == count) return;
3032 }
3033 }
3034
3035
3036 // JVMTI PopFrame support
3037 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3038 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3039 if (in_bytes(size_in_bytes) != 0) {
3040 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3041 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3042 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3043 }
3044 }
3045
3046 void* JavaThread::popframe_preserved_args() {
3047 return _popframe_preserved_args;
3048 }
3049
3050 ByteSize JavaThread::popframe_preserved_args_size() {
3051 return in_ByteSize(_popframe_preserved_args_size);
3052 }
3053
3054 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3055 int sz = in_bytes(popframe_preserved_args_size());
3056 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3057 return in_WordSize(sz / wordSize);
3058 }
3059
3060 void JavaThread::popframe_free_preserved_args() {
3061 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3062 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3063 _popframe_preserved_args = NULL;
3064 _popframe_preserved_args_size = 0;
3065 }
3066
3067 #ifndef PRODUCT
3068
3069 void JavaThread::trace_frames() {
3070 tty->print_cr("[Describe stack]");
3071 int frame_no = 1;
3072 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3073 tty->print(" %d. ", frame_no++);
3074 fst.current()->print_value_on(tty, this);
3075 tty->cr();
3076 }
3077 }
3078
3079 class PrintAndVerifyOopClosure: public OopClosure {
3080 protected:
3081 template <class T> inline void do_oop_work(T* p) {
3082 oop obj = oopDesc::load_decode_heap_oop(p);
3083 if (obj == NULL) return;
3084 tty->print(INTPTR_FORMAT ": ", p2i(p));
3085 if (obj->is_oop_or_null()) {
3086 if (obj->is_objArray()) {
3087 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3088 } else {
3089 obj->print();
3090 }
3091 } else {
3092 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3093 }
3094 tty->cr();
3095 }
3096 public:
3097 virtual void do_oop(oop* p) { do_oop_work(p); }
3098 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3099 };
3100
3101
3102 static void oops_print(frame* f, const RegisterMap *map) {
3103 PrintAndVerifyOopClosure print;
3104 f->print_value();
3105 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3106 }
3107
3108 // Print our all the locations that contain oops and whether they are
3109 // valid or not. This useful when trying to find the oldest frame
3110 // where an oop has gone bad since the frame walk is from youngest to
3111 // oldest.
3112 void JavaThread::trace_oops() {
3113 tty->print_cr("[Trace oops]");
3114 frames_do(oops_print);
3115 }
3116
3117
3118 #ifdef ASSERT
3119 // Print or validate the layout of stack frames
3120 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3121 ResourceMark rm;
3122 PRESERVE_EXCEPTION_MARK;
3123 FrameValues values;
3124 int frame_no = 0;
3125 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3126 fst.current()->describe(values, ++frame_no);
3127 if (depth == frame_no) break;
3128 }
3129 if (validate_only) {
3130 values.validate();
3131 } else {
3132 tty->print_cr("[Describe stack layout]");
3133 values.print(this);
3134 }
3135 }
3136 #endif
3137
3138 void JavaThread::trace_stack_from(vframe* start_vf) {
3139 ResourceMark rm;
3140 int vframe_no = 1;
3141 for (vframe* f = start_vf; f; f = f->sender()) {
3142 if (f->is_java_frame()) {
3143 javaVFrame::cast(f)->print_activation(vframe_no++);
3144 } else {
3145 f->print();
3146 }
3147 if (vframe_no > StackPrintLimit) {
3148 tty->print_cr("...<more frames>...");
3149 return;
3150 }
3151 }
3152 }
3153
3154
3155 void JavaThread::trace_stack() {
3156 if (!has_last_Java_frame()) return;
3157 ResourceMark rm;
3158 HandleMark hm;
3159 RegisterMap reg_map(this);
3160 trace_stack_from(last_java_vframe(®_map));
3161 }
3162
3163
3164 #endif // PRODUCT
3165
3166
3167 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3168 assert(reg_map != NULL, "a map must be given");
3169 frame f = last_frame();
3170 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3171 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3172 }
3173 return NULL;
3174 }
3175
3176
3177 Klass* JavaThread::security_get_caller_class(int depth) {
3178 vframeStream vfst(this);
3179 vfst.security_get_caller_frame(depth);
3180 if (!vfst.at_end()) {
3181 return vfst.method()->method_holder();
3182 }
3183 return NULL;
3184 }
3185
3186 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3187 assert(thread->is_Compiler_thread(), "must be compiler thread");
3188 CompileBroker::compiler_thread_loop();
3189 }
3190
3191 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3192 NMethodSweeper::sweeper_loop();
3193 }
3194
3195 // Create a CompilerThread
3196 CompilerThread::CompilerThread(CompileQueue* queue,
3197 CompilerCounters* counters)
3198 : JavaThread(&compiler_thread_entry) {
3199 _env = NULL;
3200 _log = NULL;
3201 _task = NULL;
3202 _queue = queue;
3203 _counters = counters;
3204 _buffer_blob = NULL;
3205 _compiler = NULL;
3206
3207 #ifndef PRODUCT
3208 _ideal_graph_printer = NULL;
3209 #endif
3210 }
3211
3212 bool CompilerThread::can_call_java() const {
3213 return _compiler != NULL && _compiler->is_jvmci();
3214 }
3215
3216 // Create sweeper thread
3217 CodeCacheSweeperThread::CodeCacheSweeperThread()
3218 : JavaThread(&sweeper_thread_entry) {
3219 _scanned_nmethod = NULL;
3220 }
3221 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3222 JavaThread::oops_do(f, cld_f, cf);
3223 if (_scanned_nmethod != NULL && cf != NULL) {
3224 // Safepoints can occur when the sweeper is scanning an nmethod so
3225 // process it here to make sure it isn't unloaded in the middle of
3226 // a scan.
3227 cf->do_code_blob(_scanned_nmethod);
3228 }
3229 }
3230
3231
3232 // ======= Threads ========
3233
3234 // The Threads class links together all active threads, and provides
3235 // operations over all threads. It is protected by its own Mutex
3236 // lock, which is also used in other contexts to protect thread
3237 // operations from having the thread being operated on from exiting
3238 // and going away unexpectedly (e.g., safepoint synchronization)
3239
3240 JavaThread* Threads::_thread_list = NULL;
3241 int Threads::_number_of_threads = 0;
3242 int Threads::_number_of_non_daemon_threads = 0;
3243 int Threads::_return_code = 0;
3244 int Threads::_thread_claim_parity = 0;
3245 size_t JavaThread::_stack_size_at_create = 0;
3246 #ifdef ASSERT
3247 bool Threads::_vm_complete = false;
3248 #endif
3249
3250 // All JavaThreads
3251 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3252
3253 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3254 void Threads::threads_do(ThreadClosure* tc) {
3255 assert_locked_or_safepoint(Threads_lock);
3256 // ALL_JAVA_THREADS iterates through all JavaThreads
3257 ALL_JAVA_THREADS(p) {
3258 tc->do_thread(p);
3259 }
3260 // Someday we could have a table or list of all non-JavaThreads.
3261 // For now, just manually iterate through them.
3262 tc->do_thread(VMThread::vm_thread());
3263 Universe::heap()->gc_threads_do(tc);
3264 WatcherThread *wt = WatcherThread::watcher_thread();
3265 // Strictly speaking, the following NULL check isn't sufficient to make sure
3266 // the data for WatcherThread is still valid upon being examined. However,
3267 // considering that WatchThread terminates when the VM is on the way to
3268 // exit at safepoint, the chance of the above is extremely small. The right
3269 // way to prevent termination of WatcherThread would be to acquire
3270 // Terminator_lock, but we can't do that without violating the lock rank
3271 // checking in some cases.
3272 if (wt != NULL) {
3273 tc->do_thread(wt);
3274 }
3275
3276 // If CompilerThreads ever become non-JavaThreads, add them here
3277 }
3278
3279 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3280 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3281
3282 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3283 create_vm_init_libraries();
3284 }
3285
3286 initialize_class(vmSymbols::java_lang_String(), CHECK);
3287
3288 // Inject CompactStrings value after the static initializers for String ran.
3289 java_lang_String::set_compact_strings(CompactStrings);
3290
3291 // Initialize java_lang.System (needed before creating the thread)
3292 initialize_class(vmSymbols::java_lang_System(), CHECK);
3293 // The VM creates & returns objects of this class. Make sure it's initialized.
3294 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3295 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3296 Handle thread_group = create_initial_thread_group(CHECK);
3297 Universe::set_main_thread_group(thread_group());
3298 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3299 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3300 main_thread->set_threadObj(thread_object);
3301 // Set thread status to running since main thread has
3302 // been started and running.
3303 java_lang_Thread::set_thread_status(thread_object,
3304 java_lang_Thread::RUNNABLE);
3305
3306 // The VM preresolves methods to these classes. Make sure that they get initialized
3307 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3308 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3309 call_initializeSystemClass(CHECK);
3310
3311 // get the Java runtime name after java.lang.System is initialized
3312 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3313 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3314
3315 // an instance of OutOfMemory exception has been allocated earlier
3316 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3317 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3318 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3319 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3320 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3321 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3322 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3323 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3324 }
3325
3326 void Threads::initialize_jsr292_core_classes(TRAPS) {
3327 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3328 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3329 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3330 }
3331
3332 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3333 extern void JDK_Version_init();
3334
3335 // Preinitialize version info.
3336 VM_Version::early_initialize();
3337
3338 // Check version
3339 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3340
3341 // Initialize the output stream module
3342 ostream_init();
3343
3344 // Process java launcher properties.
3345 Arguments::process_sun_java_launcher_properties(args);
3346
3347 // Initialize the os module before using TLS
3348 os::init();
3349
3350 // Record VM creation timing statistics
3351 TraceVmCreationTime create_vm_timer;
3352 create_vm_timer.start();
3353
3354 // Initialize system properties.
3355 Arguments::init_system_properties();
3356
3357 // So that JDK version can be used as a discriminator when parsing arguments
3358 JDK_Version_init();
3359
3360 // Update/Initialize System properties after JDK version number is known
3361 Arguments::init_version_specific_system_properties();
3362
3363 // Make sure to initialize log configuration *before* parsing arguments
3364 LogConfiguration::initialize(create_vm_timer.begin_time());
3365
3366 // Parse arguments
3367 jint parse_result = Arguments::parse(args);
3368 if (parse_result != JNI_OK) return parse_result;
3369
3370 os::init_before_ergo();
3371
3372 jint ergo_result = Arguments::apply_ergo();
3373 if (ergo_result != JNI_OK) return ergo_result;
3374
3375 // Final check of all ranges after ergonomics which may change values.
3376 if (!CommandLineFlagRangeList::check_ranges()) {
3377 return JNI_EINVAL;
3378 }
3379
3380 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3381 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3382 if (!constraint_result) {
3383 return JNI_EINVAL;
3384 }
3385
3386 if (PauseAtStartup) {
3387 os::pause();
3388 }
3389
3390 HOTSPOT_VM_INIT_BEGIN();
3391
3392 // Timing (must come after argument parsing)
3393 TraceTime timer("Create VM", TraceStartupTime);
3394
3395 // Initialize the os module after parsing the args
3396 jint os_init_2_result = os::init_2();
3397 if (os_init_2_result != JNI_OK) return os_init_2_result;
3398
3399 jint adjust_after_os_result = Arguments::adjust_after_os();
3400 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3401
3402 // Initialize library-based TLS
3403 ThreadLocalStorage::init();
3404
3405 // Initialize output stream logging
3406 ostream_init_log();
3407
3408 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3409 // Must be before create_vm_init_agents()
3410 if (Arguments::init_libraries_at_startup()) {
3411 convert_vm_init_libraries_to_agents();
3412 }
3413
3414 // Launch -agentlib/-agentpath and converted -Xrun agents
3415 if (Arguments::init_agents_at_startup()) {
3416 create_vm_init_agents();
3417 }
3418
3419 // Initialize Threads state
3420 _thread_list = NULL;
3421 _number_of_threads = 0;
3422 _number_of_non_daemon_threads = 0;
3423
3424 // Initialize global data structures and create system classes in heap
3425 vm_init_globals();
3426
3427 #if INCLUDE_JVMCI
3428 if (JVMCICounterSize > 0) {
3429 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3430 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3431 } else {
3432 JavaThread::_jvmci_old_thread_counters = NULL;
3433 }
3434 #endif // INCLUDE_JVMCI
3435
3436 // Attach the main thread to this os thread
3437 JavaThread* main_thread = new JavaThread();
3438 main_thread->set_thread_state(_thread_in_vm);
3439 main_thread->initialize_thread_current();
3440 // must do this before set_active_handles
3441 main_thread->record_stack_base_and_size();
3442 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3443
3444 if (!main_thread->set_as_starting_thread()) {
3445 vm_shutdown_during_initialization(
3446 "Failed necessary internal allocation. Out of swap space");
3447 delete main_thread;
3448 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3449 return JNI_ENOMEM;
3450 }
3451
3452 // Enable guard page *after* os::create_main_thread(), otherwise it would
3453 // crash Linux VM, see notes in os_linux.cpp.
3454 main_thread->create_stack_guard_pages();
3455
3456 // Initialize Java-Level synchronization subsystem
3457 ObjectMonitor::Initialize();
3458
3459 // Initialize global modules
3460 jint status = init_globals();
3461 if (status != JNI_OK) {
3462 delete main_thread;
3463 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3464 return status;
3465 }
3466
3467 // Should be done after the heap is fully created
3468 main_thread->cache_global_variables();
3469
3470 HandleMark hm;
3471
3472 { MutexLocker mu(Threads_lock);
3473 Threads::add(main_thread);
3474 }
3475
3476 // Any JVMTI raw monitors entered in onload will transition into
3477 // real raw monitor. VM is setup enough here for raw monitor enter.
3478 JvmtiExport::transition_pending_onload_raw_monitors();
3479
3480 // Create the VMThread
3481 { TraceTime timer("Start VMThread", TraceStartupTime);
3482 VMThread::create();
3483 Thread* vmthread = VMThread::vm_thread();
3484
3485 if (!os::create_thread(vmthread, os::vm_thread)) {
3486 vm_exit_during_initialization("Cannot create VM thread. "
3487 "Out of system resources.");
3488 }
3489
3490 // Wait for the VM thread to become ready, and VMThread::run to initialize
3491 // Monitors can have spurious returns, must always check another state flag
3492 {
3493 MutexLocker ml(Notify_lock);
3494 os::start_thread(vmthread);
3495 while (vmthread->active_handles() == NULL) {
3496 Notify_lock->wait();
3497 }
3498 }
3499 }
3500
3501 assert(Universe::is_fully_initialized(), "not initialized");
3502 if (VerifyDuringStartup) {
3503 // Make sure we're starting with a clean slate.
3504 VM_Verify verify_op;
3505 VMThread::execute(&verify_op);
3506 }
3507
3508 Thread* THREAD = Thread::current();
3509
3510 // At this point, the Universe is initialized, but we have not executed
3511 // any byte code. Now is a good time (the only time) to dump out the
3512 // internal state of the JVM for sharing.
3513 if (DumpSharedSpaces) {
3514 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3515 ShouldNotReachHere();
3516 }
3517
3518 // Always call even when there are not JVMTI environments yet, since environments
3519 // may be attached late and JVMTI must track phases of VM execution
3520 JvmtiExport::enter_start_phase();
3521
3522 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3523 JvmtiExport::post_vm_start();
3524
3525 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3526
3527 // We need this for ClassDataSharing - the initial vm.info property is set
3528 // with the default value of CDS "sharing" which may be reset through
3529 // command line options.
3530 reset_vm_info_property(CHECK_JNI_ERR);
3531
3532 quicken_jni_functions();
3533
3534 // Must be run after init_ft which initializes ft_enabled
3535 if (TRACE_INITIALIZE() != JNI_OK) {
3536 vm_exit_during_initialization("Failed to initialize tracing backend");
3537 }
3538
3539 // Set flag that basic initialization has completed. Used by exceptions and various
3540 // debug stuff, that does not work until all basic classes have been initialized.
3541 set_init_completed();
3542
3543 LogConfiguration::post_initialize();
3544 Metaspace::post_initialize();
3545
3546 HOTSPOT_VM_INIT_END();
3547
3548 // record VM initialization completion time
3549 #if INCLUDE_MANAGEMENT
3550 Management::record_vm_init_completed();
3551 #endif // INCLUDE_MANAGEMENT
3552
3553 // Compute system loader. Note that this has to occur after set_init_completed, since
3554 // valid exceptions may be thrown in the process.
3555 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3556 // set_init_completed has just been called, causing exceptions not to be shortcut
3557 // anymore. We call vm_exit_during_initialization directly instead.
3558 SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR));
3559
3560 #if INCLUDE_ALL_GCS
3561 // Support for ConcurrentMarkSweep. This should be cleaned up
3562 // and better encapsulated. The ugly nested if test would go away
3563 // once things are properly refactored. XXX YSR
3564 if (UseConcMarkSweepGC || UseG1GC) {
3565 if (UseConcMarkSweepGC) {
3566 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3567 } else {
3568 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3569 }
3570 }
3571 #endif // INCLUDE_ALL_GCS
3572
3573 // Always call even when there are not JVMTI environments yet, since environments
3574 // may be attached late and JVMTI must track phases of VM execution
3575 JvmtiExport::enter_live_phase();
3576
3577 // Signal Dispatcher needs to be started before VMInit event is posted
3578 os::signal_init();
3579
3580 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3581 if (!DisableAttachMechanism) {
3582 AttachListener::vm_start();
3583 if (StartAttachListener || AttachListener::init_at_startup()) {
3584 AttachListener::init();
3585 }
3586 }
3587
3588 // Launch -Xrun agents
3589 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3590 // back-end can launch with -Xdebug -Xrunjdwp.
3591 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3592 create_vm_init_libraries();
3593 }
3594
3595 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3596 JvmtiExport::post_vm_initialized();
3597
3598 if (TRACE_START() != JNI_OK) {
3599 vm_exit_during_initialization("Failed to start tracing backend.");
3600 }
3601
3602 if (CleanChunkPoolAsync) {
3603 Chunk::start_chunk_pool_cleaner_task();
3604 }
3605
3606 #if INCLUDE_JVMCI
3607 if (EnableJVMCI) {
3608 const char* jvmciCompiler = Arguments::PropertyList_get_value(Arguments::system_properties(), "jvmci.compiler");
3609 if (jvmciCompiler != NULL) {
3610 JVMCIRuntime::save_compiler(jvmciCompiler);
3611 }
3612 JVMCIRuntime::maybe_print_flags(CHECK_JNI_ERR);
3613 }
3614 #endif // INCLUDE_JVMCI
3615
3616 // initialize compiler(s)
3617 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI
3618 CompileBroker::compilation_init();
3619 #endif
3620
3621 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3622 // It is done after compilers are initialized, because otherwise compilations of
3623 // signature polymorphic MH intrinsics can be missed
3624 // (see SystemDictionary::find_method_handle_intrinsic).
3625 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3626
3627 #if INCLUDE_MANAGEMENT
3628 Management::initialize(THREAD);
3629
3630 if (HAS_PENDING_EXCEPTION) {
3631 // management agent fails to start possibly due to
3632 // configuration problem and is responsible for printing
3633 // stack trace if appropriate. Simply exit VM.
3634 vm_exit(1);
3635 }
3636 #endif // INCLUDE_MANAGEMENT
3637
3638 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3639 if (MemProfiling) MemProfiler::engage();
3640 StatSampler::engage();
3641 if (CheckJNICalls) JniPeriodicChecker::engage();
3642
3643 BiasedLocking::init();
3644
3645 #if INCLUDE_RTM_OPT
3646 RTMLockingCounters::init();
3647 #endif
3648
3649 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3650 call_postVMInitHook(THREAD);
3651 // The Java side of PostVMInitHook.run must deal with all
3652 // exceptions and provide means of diagnosis.
3653 if (HAS_PENDING_EXCEPTION) {
3654 CLEAR_PENDING_EXCEPTION;
3655 }
3656 }
3657
3658 {
3659 MutexLocker ml(PeriodicTask_lock);
3660 // Make sure the WatcherThread can be started by WatcherThread::start()
3661 // or by dynamic enrollment.
3662 WatcherThread::make_startable();
3663 // Start up the WatcherThread if there are any periodic tasks
3664 // NOTE: All PeriodicTasks should be registered by now. If they
3665 // aren't, late joiners might appear to start slowly (we might
3666 // take a while to process their first tick).
3667 if (PeriodicTask::num_tasks() > 0) {
3668 WatcherThread::start();
3669 }
3670 }
3671
3672 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3673
3674 create_vm_timer.end();
3675 #ifdef ASSERT
3676 _vm_complete = true;
3677 #endif
3678 return JNI_OK;
3679 }
3680
3681 // type for the Agent_OnLoad and JVM_OnLoad entry points
3682 extern "C" {
3683 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3684 }
3685 // Find a command line agent library and return its entry point for
3686 // -agentlib: -agentpath: -Xrun
3687 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3688 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3689 const char *on_load_symbols[],
3690 size_t num_symbol_entries) {
3691 OnLoadEntry_t on_load_entry = NULL;
3692 void *library = NULL;
3693
3694 if (!agent->valid()) {
3695 char buffer[JVM_MAXPATHLEN];
3696 char ebuf[1024] = "";
3697 const char *name = agent->name();
3698 const char *msg = "Could not find agent library ";
3699
3700 // First check to see if agent is statically linked into executable
3701 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3702 library = agent->os_lib();
3703 } else if (agent->is_absolute_path()) {
3704 library = os::dll_load(name, ebuf, sizeof ebuf);
3705 if (library == NULL) {
3706 const char *sub_msg = " in absolute path, with error: ";
3707 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3708 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3709 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3710 // If we can't find the agent, exit.
3711 vm_exit_during_initialization(buf, NULL);
3712 FREE_C_HEAP_ARRAY(char, buf);
3713 }
3714 } else {
3715 // Try to load the agent from the standard dll directory
3716 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3717 name)) {
3718 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3719 }
3720 if (library == NULL) { // Try the local directory
3721 char ns[1] = {0};
3722 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3723 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3724 }
3725 if (library == NULL) {
3726 const char *sub_msg = " on the library path, with error: ";
3727 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3728 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3729 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3730 // If we can't find the agent, exit.
3731 vm_exit_during_initialization(buf, NULL);
3732 FREE_C_HEAP_ARRAY(char, buf);
3733 }
3734 }
3735 }
3736 agent->set_os_lib(library);
3737 agent->set_valid();
3738 }
3739
3740 // Find the OnLoad function.
3741 on_load_entry =
3742 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3743 false,
3744 on_load_symbols,
3745 num_symbol_entries));
3746 return on_load_entry;
3747 }
3748
3749 // Find the JVM_OnLoad entry point
3750 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3751 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3752 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3753 }
3754
3755 // Find the Agent_OnLoad entry point
3756 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3757 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3758 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3759 }
3760
3761 // For backwards compatibility with -Xrun
3762 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3763 // treated like -agentpath:
3764 // Must be called before agent libraries are created
3765 void Threads::convert_vm_init_libraries_to_agents() {
3766 AgentLibrary* agent;
3767 AgentLibrary* next;
3768
3769 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3770 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3771 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3772
3773 // If there is an JVM_OnLoad function it will get called later,
3774 // otherwise see if there is an Agent_OnLoad
3775 if (on_load_entry == NULL) {
3776 on_load_entry = lookup_agent_on_load(agent);
3777 if (on_load_entry != NULL) {
3778 // switch it to the agent list -- so that Agent_OnLoad will be called,
3779 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3780 Arguments::convert_library_to_agent(agent);
3781 } else {
3782 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3783 }
3784 }
3785 }
3786 }
3787
3788 // Create agents for -agentlib: -agentpath: and converted -Xrun
3789 // Invokes Agent_OnLoad
3790 // Called very early -- before JavaThreads exist
3791 void Threads::create_vm_init_agents() {
3792 extern struct JavaVM_ main_vm;
3793 AgentLibrary* agent;
3794
3795 JvmtiExport::enter_onload_phase();
3796
3797 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3798 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3799
3800 if (on_load_entry != NULL) {
3801 // Invoke the Agent_OnLoad function
3802 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3803 if (err != JNI_OK) {
3804 vm_exit_during_initialization("agent library failed to init", agent->name());
3805 }
3806 } else {
3807 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3808 }
3809 }
3810 JvmtiExport::enter_primordial_phase();
3811 }
3812
3813 extern "C" {
3814 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3815 }
3816
3817 void Threads::shutdown_vm_agents() {
3818 // Send any Agent_OnUnload notifications
3819 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3820 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3821 extern struct JavaVM_ main_vm;
3822 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3823
3824 // Find the Agent_OnUnload function.
3825 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3826 os::find_agent_function(agent,
3827 false,
3828 on_unload_symbols,
3829 num_symbol_entries));
3830
3831 // Invoke the Agent_OnUnload function
3832 if (unload_entry != NULL) {
3833 JavaThread* thread = JavaThread::current();
3834 ThreadToNativeFromVM ttn(thread);
3835 HandleMark hm(thread);
3836 (*unload_entry)(&main_vm);
3837 }
3838 }
3839 }
3840
3841 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3842 // Invokes JVM_OnLoad
3843 void Threads::create_vm_init_libraries() {
3844 extern struct JavaVM_ main_vm;
3845 AgentLibrary* agent;
3846
3847 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3848 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3849
3850 if (on_load_entry != NULL) {
3851 // Invoke the JVM_OnLoad function
3852 JavaThread* thread = JavaThread::current();
3853 ThreadToNativeFromVM ttn(thread);
3854 HandleMark hm(thread);
3855 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3856 if (err != JNI_OK) {
3857 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3858 }
3859 } else {
3860 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3861 }
3862 }
3863 }
3864
3865 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3866 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3867
3868 JavaThread* java_thread = NULL;
3869 // Sequential search for now. Need to do better optimization later.
3870 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3871 oop tobj = thread->threadObj();
3872 if (!thread->is_exiting() &&
3873 tobj != NULL &&
3874 java_tid == java_lang_Thread::thread_id(tobj)) {
3875 java_thread = thread;
3876 break;
3877 }
3878 }
3879 return java_thread;
3880 }
3881
3882
3883 // Last thread running calls java.lang.Shutdown.shutdown()
3884 void JavaThread::invoke_shutdown_hooks() {
3885 HandleMark hm(this);
3886
3887 // We could get here with a pending exception, if so clear it now.
3888 if (this->has_pending_exception()) {
3889 this->clear_pending_exception();
3890 }
3891
3892 EXCEPTION_MARK;
3893 Klass* k =
3894 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3895 THREAD);
3896 if (k != NULL) {
3897 // SystemDictionary::resolve_or_null will return null if there was
3898 // an exception. If we cannot load the Shutdown class, just don't
3899 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3900 // and finalizers (if runFinalizersOnExit is set) won't be run.
3901 // Note that if a shutdown hook was registered or runFinalizersOnExit
3902 // was called, the Shutdown class would have already been loaded
3903 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3904 instanceKlassHandle shutdown_klass (THREAD, k);
3905 JavaValue result(T_VOID);
3906 JavaCalls::call_static(&result,
3907 shutdown_klass,
3908 vmSymbols::shutdown_method_name(),
3909 vmSymbols::void_method_signature(),
3910 THREAD);
3911 }
3912 CLEAR_PENDING_EXCEPTION;
3913 }
3914
3915 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3916 // the program falls off the end of main(). Another VM exit path is through
3917 // vm_exit() when the program calls System.exit() to return a value or when
3918 // there is a serious error in VM. The two shutdown paths are not exactly
3919 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3920 // and VM_Exit op at VM level.
3921 //
3922 // Shutdown sequence:
3923 // + Shutdown native memory tracking if it is on
3924 // + Wait until we are the last non-daemon thread to execute
3925 // <-- every thing is still working at this moment -->
3926 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3927 // shutdown hooks, run finalizers if finalization-on-exit
3928 // + Call before_exit(), prepare for VM exit
3929 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3930 // currently the only user of this mechanism is File.deleteOnExit())
3931 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3932 // post thread end and vm death events to JVMTI,
3933 // stop signal thread
3934 // + Call JavaThread::exit(), it will:
3935 // > release JNI handle blocks, remove stack guard pages
3936 // > remove this thread from Threads list
3937 // <-- no more Java code from this thread after this point -->
3938 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3939 // the compiler threads at safepoint
3940 // <-- do not use anything that could get blocked by Safepoint -->
3941 // + Disable tracing at JNI/JVM barriers
3942 // + Set _vm_exited flag for threads that are still running native code
3943 // + Delete this thread
3944 // + Call exit_globals()
3945 // > deletes tty
3946 // > deletes PerfMemory resources
3947 // + Return to caller
3948
3949 bool Threads::destroy_vm() {
3950 JavaThread* thread = JavaThread::current();
3951
3952 #ifdef ASSERT
3953 _vm_complete = false;
3954 #endif
3955 // Wait until we are the last non-daemon thread to execute
3956 { MutexLocker nu(Threads_lock);
3957 while (Threads::number_of_non_daemon_threads() > 1)
3958 // This wait should make safepoint checks, wait without a timeout,
3959 // and wait as a suspend-equivalent condition.
3960 //
3961 // Note: If the FlatProfiler is running and this thread is waiting
3962 // for another non-daemon thread to finish, then the FlatProfiler
3963 // is waiting for the external suspend request on this thread to
3964 // complete. wait_for_ext_suspend_completion() will eventually
3965 // timeout, but that takes time. Making this wait a suspend-
3966 // equivalent condition solves that timeout problem.
3967 //
3968 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3969 Mutex::_as_suspend_equivalent_flag);
3970 }
3971
3972 // Hang forever on exit if we are reporting an error.
3973 if (ShowMessageBoxOnError && is_error_reported()) {
3974 os::infinite_sleep();
3975 }
3976 os::wait_for_keypress_at_exit();
3977
3978 // run Java level shutdown hooks
3979 thread->invoke_shutdown_hooks();
3980
3981 before_exit(thread);
3982
3983 thread->exit(true);
3984
3985 // Stop VM thread.
3986 {
3987 // 4945125 The vm thread comes to a safepoint during exit.
3988 // GC vm_operations can get caught at the safepoint, and the
3989 // heap is unparseable if they are caught. Grab the Heap_lock
3990 // to prevent this. The GC vm_operations will not be able to
3991 // queue until after the vm thread is dead. After this point,
3992 // we'll never emerge out of the safepoint before the VM exits.
3993
3994 MutexLocker ml(Heap_lock);
3995
3996 VMThread::wait_for_vm_thread_exit();
3997 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3998 VMThread::destroy();
3999 }
4000
4001 // clean up ideal graph printers
4002 #if defined(COMPILER2) && !defined(PRODUCT)
4003 IdealGraphPrinter::clean_up();
4004 #endif
4005
4006 // Now, all Java threads are gone except daemon threads. Daemon threads
4007 // running Java code or in VM are stopped by the Safepoint. However,
4008 // daemon threads executing native code are still running. But they
4009 // will be stopped at native=>Java/VM barriers. Note that we can't
4010 // simply kill or suspend them, as it is inherently deadlock-prone.
4011
4012 #ifndef PRODUCT
4013 // disable function tracing at JNI/JVM barriers
4014 TraceJNICalls = false;
4015 TraceJVMCalls = false;
4016 TraceRuntimeCalls = false;
4017 #endif
4018
4019 VM_Exit::set_vm_exited();
4020
4021 notify_vm_shutdown();
4022
4023 delete thread;
4024
4025 #if INCLUDE_JVMCI
4026 if (JVMCICounterSize > 0) {
4027 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4028 }
4029 #endif
4030
4031 // exit_globals() will delete tty
4032 exit_globals();
4033
4034 LogConfiguration::finalize();
4035
4036 return true;
4037 }
4038
4039
4040 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4041 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4042 return is_supported_jni_version(version);
4043 }
4044
4045
4046 jboolean Threads::is_supported_jni_version(jint version) {
4047 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4048 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4049 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4050 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4051 return JNI_FALSE;
4052 }
4053
4054
4055 void Threads::add(JavaThread* p, bool force_daemon) {
4056 // The threads lock must be owned at this point
4057 assert_locked_or_safepoint(Threads_lock);
4058
4059 // See the comment for this method in thread.hpp for its purpose and
4060 // why it is called here.
4061 p->initialize_queues();
4062 p->set_next(_thread_list);
4063 _thread_list = p;
4064 _number_of_threads++;
4065 oop threadObj = p->threadObj();
4066 bool daemon = true;
4067 // Bootstrapping problem: threadObj can be null for initial
4068 // JavaThread (or for threads attached via JNI)
4069 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4070 _number_of_non_daemon_threads++;
4071 daemon = false;
4072 }
4073
4074 ThreadService::add_thread(p, daemon);
4075
4076 // Possible GC point.
4077 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4078 }
4079
4080 void Threads::remove(JavaThread* p) {
4081 // Extra scope needed for Thread_lock, so we can check
4082 // that we do not remove thread without safepoint code notice
4083 { MutexLocker ml(Threads_lock);
4084
4085 assert(includes(p), "p must be present");
4086
4087 JavaThread* current = _thread_list;
4088 JavaThread* prev = NULL;
4089
4090 while (current != p) {
4091 prev = current;
4092 current = current->next();
4093 }
4094
4095 if (prev) {
4096 prev->set_next(current->next());
4097 } else {
4098 _thread_list = p->next();
4099 }
4100 _number_of_threads--;
4101 oop threadObj = p->threadObj();
4102 bool daemon = true;
4103 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4104 _number_of_non_daemon_threads--;
4105 daemon = false;
4106
4107 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4108 // on destroy_vm will wake up.
4109 if (number_of_non_daemon_threads() == 1) {
4110 Threads_lock->notify_all();
4111 }
4112 }
4113 ThreadService::remove_thread(p, daemon);
4114
4115 // Make sure that safepoint code disregard this thread. This is needed since
4116 // the thread might mess around with locks after this point. This can cause it
4117 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4118 // of this thread since it is removed from the queue.
4119 p->set_terminated_value();
4120 } // unlock Threads_lock
4121
4122 // Since Events::log uses a lock, we grab it outside the Threads_lock
4123 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4124 }
4125
4126 // Threads_lock must be held when this is called (or must be called during a safepoint)
4127 bool Threads::includes(JavaThread* p) {
4128 assert(Threads_lock->is_locked(), "sanity check");
4129 ALL_JAVA_THREADS(q) {
4130 if (q == p) {
4131 return true;
4132 }
4133 }
4134 return false;
4135 }
4136
4137 // Operations on the Threads list for GC. These are not explicitly locked,
4138 // but the garbage collector must provide a safe context for them to run.
4139 // In particular, these things should never be called when the Threads_lock
4140 // is held by some other thread. (Note: the Safepoint abstraction also
4141 // uses the Threads_lock to guarantee this property. It also makes sure that
4142 // all threads gets blocked when exiting or starting).
4143
4144 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4145 ALL_JAVA_THREADS(p) {
4146 p->oops_do(f, cld_f, cf);
4147 }
4148 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4149 }
4150
4151 void Threads::change_thread_claim_parity() {
4152 // Set the new claim parity.
4153 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4154 "Not in range.");
4155 _thread_claim_parity++;
4156 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4157 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4158 "Not in range.");
4159 }
4160
4161 #ifdef ASSERT
4162 void Threads::assert_all_threads_claimed() {
4163 ALL_JAVA_THREADS(p) {
4164 const int thread_parity = p->oops_do_parity();
4165 assert((thread_parity == _thread_claim_parity),
4166 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4167 }
4168 }
4169 #endif // ASSERT
4170
4171 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4172 int cp = Threads::thread_claim_parity();
4173 ALL_JAVA_THREADS(p) {
4174 if (p->claim_oops_do(is_par, cp)) {
4175 p->oops_do(f, cld_f, cf);
4176 }
4177 }
4178 VMThread* vmt = VMThread::vm_thread();
4179 if (vmt->claim_oops_do(is_par, cp)) {
4180 vmt->oops_do(f, cld_f, cf);
4181 }
4182 }
4183
4184 #if INCLUDE_ALL_GCS
4185 // Used by ParallelScavenge
4186 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4187 ALL_JAVA_THREADS(p) {
4188 q->enqueue(new ThreadRootsTask(p));
4189 }
4190 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4191 }
4192
4193 // Used by Parallel Old
4194 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4195 ALL_JAVA_THREADS(p) {
4196 q->enqueue(new ThreadRootsMarkingTask(p));
4197 }
4198 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4199 }
4200 #endif // INCLUDE_ALL_GCS
4201
4202 void Threads::nmethods_do(CodeBlobClosure* cf) {
4203 ALL_JAVA_THREADS(p) {
4204 p->nmethods_do(cf);
4205 }
4206 VMThread::vm_thread()->nmethods_do(cf);
4207 }
4208
4209 void Threads::metadata_do(void f(Metadata*)) {
4210 ALL_JAVA_THREADS(p) {
4211 p->metadata_do(f);
4212 }
4213 }
4214
4215 class ThreadHandlesClosure : public ThreadClosure {
4216 void (*_f)(Metadata*);
4217 public:
4218 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4219 virtual void do_thread(Thread* thread) {
4220 thread->metadata_handles_do(_f);
4221 }
4222 };
4223
4224 void Threads::metadata_handles_do(void f(Metadata*)) {
4225 // Only walk the Handles in Thread.
4226 ThreadHandlesClosure handles_closure(f);
4227 threads_do(&handles_closure);
4228 }
4229
4230 void Threads::deoptimized_wrt_marked_nmethods() {
4231 ALL_JAVA_THREADS(p) {
4232 p->deoptimized_wrt_marked_nmethods();
4233 }
4234 }
4235
4236
4237 // Get count Java threads that are waiting to enter the specified monitor.
4238 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4239 address monitor,
4240 bool doLock) {
4241 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4242 "must grab Threads_lock or be at safepoint");
4243 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4244
4245 int i = 0;
4246 {
4247 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4248 ALL_JAVA_THREADS(p) {
4249 if (!p->can_call_java()) continue;
4250
4251 address pending = (address)p->current_pending_monitor();
4252 if (pending == monitor) { // found a match
4253 if (i < count) result->append(p); // save the first count matches
4254 i++;
4255 }
4256 }
4257 }
4258 return result;
4259 }
4260
4261
4262 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4263 bool doLock) {
4264 assert(doLock ||
4265 Threads_lock->owned_by_self() ||
4266 SafepointSynchronize::is_at_safepoint(),
4267 "must grab Threads_lock or be at safepoint");
4268
4269 // NULL owner means not locked so we can skip the search
4270 if (owner == NULL) return NULL;
4271
4272 {
4273 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4274 ALL_JAVA_THREADS(p) {
4275 // first, see if owner is the address of a Java thread
4276 if (owner == (address)p) return p;
4277 }
4278 }
4279 // Cannot assert on lack of success here since this function may be
4280 // used by code that is trying to report useful problem information
4281 // like deadlock detection.
4282 if (UseHeavyMonitors) return NULL;
4283
4284 // If we didn't find a matching Java thread and we didn't force use of
4285 // heavyweight monitors, then the owner is the stack address of the
4286 // Lock Word in the owning Java thread's stack.
4287 //
4288 JavaThread* the_owner = NULL;
4289 {
4290 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4291 ALL_JAVA_THREADS(q) {
4292 if (q->is_lock_owned(owner)) {
4293 the_owner = q;
4294 break;
4295 }
4296 }
4297 }
4298 // cannot assert on lack of success here; see above comment
4299 return the_owner;
4300 }
4301
4302 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4303 void Threads::print_on(outputStream* st, bool print_stacks,
4304 bool internal_format, bool print_concurrent_locks) {
4305 char buf[32];
4306 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4307
4308 st->print_cr("Full thread dump %s (%s %s):",
4309 Abstract_VM_Version::vm_name(),
4310 Abstract_VM_Version::vm_release(),
4311 Abstract_VM_Version::vm_info_string());
4312 st->cr();
4313
4314 #if INCLUDE_SERVICES
4315 // Dump concurrent locks
4316 ConcurrentLocksDump concurrent_locks;
4317 if (print_concurrent_locks) {
4318 concurrent_locks.dump_at_safepoint();
4319 }
4320 #endif // INCLUDE_SERVICES
4321
4322 ALL_JAVA_THREADS(p) {
4323 ResourceMark rm;
4324 p->print_on(st);
4325 if (print_stacks) {
4326 if (internal_format) {
4327 p->trace_stack();
4328 } else {
4329 p->print_stack_on(st);
4330 }
4331 }
4332 st->cr();
4333 #if INCLUDE_SERVICES
4334 if (print_concurrent_locks) {
4335 concurrent_locks.print_locks_on(p, st);
4336 }
4337 #endif // INCLUDE_SERVICES
4338 }
4339
4340 VMThread::vm_thread()->print_on(st);
4341 st->cr();
4342 Universe::heap()->print_gc_threads_on(st);
4343 WatcherThread* wt = WatcherThread::watcher_thread();
4344 if (wt != NULL) {
4345 wt->print_on(st);
4346 st->cr();
4347 }
4348 CompileBroker::print_compiler_threads_on(st);
4349 st->flush();
4350 }
4351
4352 // Threads::print_on_error() is called by fatal error handler. It's possible
4353 // that VM is not at safepoint and/or current thread is inside signal handler.
4354 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4355 // memory (even in resource area), it might deadlock the error handler.
4356 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4357 int buflen) {
4358 bool found_current = false;
4359 st->print_cr("Java Threads: ( => current thread )");
4360 ALL_JAVA_THREADS(thread) {
4361 bool is_current = (current == thread);
4362 found_current = found_current || is_current;
4363
4364 st->print("%s", is_current ? "=>" : " ");
4365
4366 st->print(PTR_FORMAT, p2i(thread));
4367 st->print(" ");
4368 thread->print_on_error(st, buf, buflen);
4369 st->cr();
4370 }
4371 st->cr();
4372
4373 st->print_cr("Other Threads:");
4374 if (VMThread::vm_thread()) {
4375 bool is_current = (current == VMThread::vm_thread());
4376 found_current = found_current || is_current;
4377 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4378
4379 st->print(PTR_FORMAT, p2i(VMThread::vm_thread()));
4380 st->print(" ");
4381 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4382 st->cr();
4383 }
4384 WatcherThread* wt = WatcherThread::watcher_thread();
4385 if (wt != NULL) {
4386 bool is_current = (current == wt);
4387 found_current = found_current || is_current;
4388 st->print("%s", is_current ? "=>" : " ");
4389
4390 st->print(PTR_FORMAT, p2i(wt));
4391 st->print(" ");
4392 wt->print_on_error(st, buf, buflen);
4393 st->cr();
4394 }
4395 if (!found_current) {
4396 st->cr();
4397 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4398 current->print_on_error(st, buf, buflen);
4399 st->cr();
4400 }
4401 }
4402
4403 // Internal SpinLock and Mutex
4404 // Based on ParkEvent
4405
4406 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4407 //
4408 // We employ SpinLocks _only for low-contention, fixed-length
4409 // short-duration critical sections where we're concerned
4410 // about native mutex_t or HotSpot Mutex:: latency.
4411 // The mux construct provides a spin-then-block mutual exclusion
4412 // mechanism.
4413 //
4414 // Testing has shown that contention on the ListLock guarding gFreeList
4415 // is common. If we implement ListLock as a simple SpinLock it's common
4416 // for the JVM to devolve to yielding with little progress. This is true
4417 // despite the fact that the critical sections protected by ListLock are
4418 // extremely short.
4419 //
4420 // TODO-FIXME: ListLock should be of type SpinLock.
4421 // We should make this a 1st-class type, integrated into the lock
4422 // hierarchy as leaf-locks. Critically, the SpinLock structure
4423 // should have sufficient padding to avoid false-sharing and excessive
4424 // cache-coherency traffic.
4425
4426
4427 typedef volatile int SpinLockT;
4428
4429 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4430 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4431 return; // normal fast-path return
4432 }
4433
4434 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4435 TEVENT(SpinAcquire - ctx);
4436 int ctr = 0;
4437 int Yields = 0;
4438 for (;;) {
4439 while (*adr != 0) {
4440 ++ctr;
4441 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4442 if (Yields > 5) {
4443 os::naked_short_sleep(1);
4444 } else {
4445 os::naked_yield();
4446 ++Yields;
4447 }
4448 } else {
4449 SpinPause();
4450 }
4451 }
4452 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4453 }
4454 }
4455
4456 void Thread::SpinRelease(volatile int * adr) {
4457 assert(*adr != 0, "invariant");
4458 OrderAccess::fence(); // guarantee at least release consistency.
4459 // Roach-motel semantics.
4460 // It's safe if subsequent LDs and STs float "up" into the critical section,
4461 // but prior LDs and STs within the critical section can't be allowed
4462 // to reorder or float past the ST that releases the lock.
4463 // Loads and stores in the critical section - which appear in program
4464 // order before the store that releases the lock - must also appear
4465 // before the store that releases the lock in memory visibility order.
4466 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4467 // the ST of 0 into the lock-word which releases the lock, so fence
4468 // more than covers this on all platforms.
4469 *adr = 0;
4470 }
4471
4472 // muxAcquire and muxRelease:
4473 //
4474 // * muxAcquire and muxRelease support a single-word lock-word construct.
4475 // The LSB of the word is set IFF the lock is held.
4476 // The remainder of the word points to the head of a singly-linked list
4477 // of threads blocked on the lock.
4478 //
4479 // * The current implementation of muxAcquire-muxRelease uses its own
4480 // dedicated Thread._MuxEvent instance. If we're interested in
4481 // minimizing the peak number of extant ParkEvent instances then
4482 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4483 // as certain invariants were satisfied. Specifically, care would need
4484 // to be taken with regards to consuming unpark() "permits".
4485 // A safe rule of thumb is that a thread would never call muxAcquire()
4486 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4487 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4488 // consume an unpark() permit intended for monitorenter, for instance.
4489 // One way around this would be to widen the restricted-range semaphore
4490 // implemented in park(). Another alternative would be to provide
4491 // multiple instances of the PlatformEvent() for each thread. One
4492 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4493 //
4494 // * Usage:
4495 // -- Only as leaf locks
4496 // -- for short-term locking only as muxAcquire does not perform
4497 // thread state transitions.
4498 //
4499 // Alternatives:
4500 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4501 // but with parking or spin-then-park instead of pure spinning.
4502 // * Use Taura-Oyama-Yonenzawa locks.
4503 // * It's possible to construct a 1-0 lock if we encode the lockword as
4504 // (List,LockByte). Acquire will CAS the full lockword while Release
4505 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4506 // acquiring threads use timers (ParkTimed) to detect and recover from
4507 // the stranding window. Thread/Node structures must be aligned on 256-byte
4508 // boundaries by using placement-new.
4509 // * Augment MCS with advisory back-link fields maintained with CAS().
4510 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4511 // The validity of the backlinks must be ratified before we trust the value.
4512 // If the backlinks are invalid the exiting thread must back-track through the
4513 // the forward links, which are always trustworthy.
4514 // * Add a successor indication. The LockWord is currently encoded as
4515 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4516 // to provide the usual futile-wakeup optimization.
4517 // See RTStt for details.
4518 // * Consider schedctl.sc_nopreempt to cover the critical section.
4519 //
4520
4521
4522 typedef volatile intptr_t MutexT; // Mux Lock-word
4523 enum MuxBits { LOCKBIT = 1 };
4524
4525 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4526 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4527 if (w == 0) return;
4528 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4529 return;
4530 }
4531
4532 TEVENT(muxAcquire - Contention);
4533 ParkEvent * const Self = Thread::current()->_MuxEvent;
4534 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4535 for (;;) {
4536 int its = (os::is_MP() ? 100 : 0) + 1;
4537
4538 // Optional spin phase: spin-then-park strategy
4539 while (--its >= 0) {
4540 w = *Lock;
4541 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4542 return;
4543 }
4544 }
4545
4546 Self->reset();
4547 Self->OnList = intptr_t(Lock);
4548 // The following fence() isn't _strictly necessary as the subsequent
4549 // CAS() both serializes execution and ratifies the fetched *Lock value.
4550 OrderAccess::fence();
4551 for (;;) {
4552 w = *Lock;
4553 if ((w & LOCKBIT) == 0) {
4554 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4555 Self->OnList = 0; // hygiene - allows stronger asserts
4556 return;
4557 }
4558 continue; // Interference -- *Lock changed -- Just retry
4559 }
4560 assert(w & LOCKBIT, "invariant");
4561 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4562 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4563 }
4564
4565 while (Self->OnList != 0) {
4566 Self->park();
4567 }
4568 }
4569 }
4570
4571 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4572 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4573 if (w == 0) return;
4574 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4575 return;
4576 }
4577
4578 TEVENT(muxAcquire - Contention);
4579 ParkEvent * ReleaseAfter = NULL;
4580 if (ev == NULL) {
4581 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4582 }
4583 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4584 for (;;) {
4585 guarantee(ev->OnList == 0, "invariant");
4586 int its = (os::is_MP() ? 100 : 0) + 1;
4587
4588 // Optional spin phase: spin-then-park strategy
4589 while (--its >= 0) {
4590 w = *Lock;
4591 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4592 if (ReleaseAfter != NULL) {
4593 ParkEvent::Release(ReleaseAfter);
4594 }
4595 return;
4596 }
4597 }
4598
4599 ev->reset();
4600 ev->OnList = intptr_t(Lock);
4601 // The following fence() isn't _strictly necessary as the subsequent
4602 // CAS() both serializes execution and ratifies the fetched *Lock value.
4603 OrderAccess::fence();
4604 for (;;) {
4605 w = *Lock;
4606 if ((w & LOCKBIT) == 0) {
4607 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4608 ev->OnList = 0;
4609 // We call ::Release while holding the outer lock, thus
4610 // artificially lengthening the critical section.
4611 // Consider deferring the ::Release() until the subsequent unlock(),
4612 // after we've dropped the outer lock.
4613 if (ReleaseAfter != NULL) {
4614 ParkEvent::Release(ReleaseAfter);
4615 }
4616 return;
4617 }
4618 continue; // Interference -- *Lock changed -- Just retry
4619 }
4620 assert(w & LOCKBIT, "invariant");
4621 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4622 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4623 }
4624
4625 while (ev->OnList != 0) {
4626 ev->park();
4627 }
4628 }
4629 }
4630
4631 // Release() must extract a successor from the list and then wake that thread.
4632 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4633 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4634 // Release() would :
4635 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4636 // (B) Extract a successor from the private list "in-hand"
4637 // (C) attempt to CAS() the residual back into *Lock over null.
4638 // If there were any newly arrived threads and the CAS() would fail.
4639 // In that case Release() would detach the RATs, re-merge the list in-hand
4640 // with the RATs and repeat as needed. Alternately, Release() might
4641 // detach and extract a successor, but then pass the residual list to the wakee.
4642 // The wakee would be responsible for reattaching and remerging before it
4643 // competed for the lock.
4644 //
4645 // Both "pop" and DMR are immune from ABA corruption -- there can be
4646 // multiple concurrent pushers, but only one popper or detacher.
4647 // This implementation pops from the head of the list. This is unfair,
4648 // but tends to provide excellent throughput as hot threads remain hot.
4649 // (We wake recently run threads first).
4650 //
4651 // All paths through muxRelease() will execute a CAS.
4652 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4653 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4654 // executed within the critical section are complete and globally visible before the
4655 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4656 void Thread::muxRelease(volatile intptr_t * Lock) {
4657 for (;;) {
4658 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4659 assert(w & LOCKBIT, "invariant");
4660 if (w == LOCKBIT) return;
4661 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4662 assert(List != NULL, "invariant");
4663 assert(List->OnList == intptr_t(Lock), "invariant");
4664 ParkEvent * const nxt = List->ListNext;
4665 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4666
4667 // The following CAS() releases the lock and pops the head element.
4668 // The CAS() also ratifies the previously fetched lock-word value.
4669 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4670 continue;
4671 }
4672 List->OnList = 0;
4673 OrderAccess::fence();
4674 List->unpark();
4675 return;
4676 }
4677 }
4678
4679
4680 void Threads::verify() {
4681 ALL_JAVA_THREADS(p) {
4682 p->verify();
4683 }
4684 VMThread* thread = VMThread::vm_thread();
4685 if (thread != NULL) thread->verify();
4686 }