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 #ifndef USE_LIBRARY_BASED_TLS_ONLY
299 _thr_current = NULL;
300 #endif
301 ThreadLocalStorage::set_thread(NULL);
302 }
303
304 void Thread::record_stack_base_and_size() {
305 set_stack_base(os::current_stack_base());
306 set_stack_size(os::current_stack_size());
307 if (is_Java_thread()) {
308 ((JavaThread*) this)->set_stack_overflow_limit();
309 }
310 // CR 7190089: on Solaris, primordial thread's stack is adjusted
311 // in initialize_thread(). Without the adjustment, stack size is
312 // incorrect if stack is set to unlimited (ulimit -s unlimited).
313 // So far, only Solaris has real implementation of initialize_thread().
314 //
315 // set up any platform-specific state.
316 os::initialize_thread(this);
317
318 #if INCLUDE_NMT
319 // record thread's native stack, stack grows downward
320 address stack_low_addr = stack_base() - stack_size();
321 MemTracker::record_thread_stack(stack_low_addr, stack_size());
322 #endif // INCLUDE_NMT
323 }
324
325
326 Thread::~Thread() {
327 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
328 ObjectSynchronizer::omFlush(this);
329
330 EVENT_THREAD_DESTRUCT(this);
331
332 // stack_base can be NULL if the thread is never started or exited before
333 // record_stack_base_and_size called. Although, we would like to ensure
334 // that all started threads do call record_stack_base_and_size(), there is
335 // not proper way to enforce that.
336 #if INCLUDE_NMT
337 if (_stack_base != NULL) {
338 address low_stack_addr = stack_base() - stack_size();
339 MemTracker::release_thread_stack(low_stack_addr, stack_size());
340 #ifdef ASSERT
341 set_stack_base(NULL);
342 #endif
343 }
344 #endif // INCLUDE_NMT
345
346 // deallocate data structures
347 delete resource_area();
348 // since the handle marks are using the handle area, we have to deallocated the root
349 // handle mark before deallocating the thread's handle area,
350 assert(last_handle_mark() != NULL, "check we have an element");
351 delete last_handle_mark();
352 assert(last_handle_mark() == NULL, "check we have reached the end");
353
354 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
355 // We NULL out the fields for good hygiene.
356 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
357 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
358 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
359 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
360
361 delete handle_area();
362 delete metadata_handles();
363
364 // osthread() can be NULL, if creation of thread failed.
365 if (osthread() != NULL) os::free_thread(osthread());
366
367 delete _SR_lock;
368
369 // clear Thread::current if thread is deleting itself.
370 // Needed to ensure JNI correctly detects non-attached threads.
371 if (this == Thread::current()) {
372 clear_thread_current();
373 }
374
375 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
376 }
377
378 // NOTE: dummy function for assertion purpose.
379 void Thread::run() {
380 ShouldNotReachHere();
381 }
382
383 #ifdef ASSERT
384 // Private method to check for dangling thread pointer
385 void check_for_dangling_thread_pointer(Thread *thread) {
386 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
387 "possibility of dangling Thread pointer");
388 }
389 #endif
390
391 ThreadPriority Thread::get_priority(const Thread* const thread) {
392 ThreadPriority priority;
393 // Can return an error!
394 (void)os::get_priority(thread, priority);
395 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
396 return priority;
397 }
398
399 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
400 debug_only(check_for_dangling_thread_pointer(thread);)
401 // Can return an error!
402 (void)os::set_priority(thread, priority);
403 }
404
405
406 void Thread::start(Thread* thread) {
407 // Start is different from resume in that its safety is guaranteed by context or
408 // being called from a Java method synchronized on the Thread object.
409 if (!DisableStartThread) {
410 if (thread->is_Java_thread()) {
411 // Initialize the thread state to RUNNABLE before starting this thread.
412 // Can not set it after the thread started because we do not know the
413 // exact thread state at that time. It could be in MONITOR_WAIT or
414 // in SLEEPING or some other state.
415 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
416 java_lang_Thread::RUNNABLE);
417 }
418 os::start_thread(thread);
419 }
420 }
421
422 // Enqueue a VM_Operation to do the job for us - sometime later
423 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
424 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
425 VMThread::execute(vm_stop);
426 }
427
428
429 // Check if an external suspend request has completed (or has been
430 // cancelled). Returns true if the thread is externally suspended and
431 // false otherwise.
432 //
433 // The bits parameter returns information about the code path through
434 // the routine. Useful for debugging:
435 //
436 // set in is_ext_suspend_completed():
437 // 0x00000001 - routine was entered
438 // 0x00000010 - routine return false at end
439 // 0x00000100 - thread exited (return false)
440 // 0x00000200 - suspend request cancelled (return false)
441 // 0x00000400 - thread suspended (return true)
442 // 0x00001000 - thread is in a suspend equivalent state (return true)
443 // 0x00002000 - thread is native and walkable (return true)
444 // 0x00004000 - thread is native_trans and walkable (needed retry)
445 //
446 // set in wait_for_ext_suspend_completion():
447 // 0x00010000 - routine was entered
448 // 0x00020000 - suspend request cancelled before loop (return false)
449 // 0x00040000 - thread suspended before loop (return true)
450 // 0x00080000 - suspend request cancelled in loop (return false)
451 // 0x00100000 - thread suspended in loop (return true)
452 // 0x00200000 - suspend not completed during retry loop (return false)
453
454 // Helper class for tracing suspend wait debug bits.
455 //
456 // 0x00000100 indicates that the target thread exited before it could
457 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
458 // 0x00080000 each indicate a cancelled suspend request so they don't
459 // count as wait failures either.
460 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
461
462 class TraceSuspendDebugBits : public StackObj {
463 private:
464 JavaThread * jt;
465 bool is_wait;
466 bool called_by_wait; // meaningful when !is_wait
467 uint32_t * bits;
468
469 public:
470 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
471 uint32_t *_bits) {
472 jt = _jt;
473 is_wait = _is_wait;
474 called_by_wait = _called_by_wait;
475 bits = _bits;
476 }
477
478 ~TraceSuspendDebugBits() {
479 if (!is_wait) {
480 #if 1
481 // By default, don't trace bits for is_ext_suspend_completed() calls.
482 // That trace is very chatty.
483 return;
484 #else
485 if (!called_by_wait) {
486 // If tracing for is_ext_suspend_completed() is enabled, then only
487 // trace calls to it from wait_for_ext_suspend_completion()
488 return;
489 }
490 #endif
491 }
492
493 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
494 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
495 MutexLocker ml(Threads_lock); // needed for get_thread_name()
496 ResourceMark rm;
497
498 tty->print_cr(
499 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
500 jt->get_thread_name(), *bits);
501
502 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
503 }
504 }
505 }
506 };
507 #undef DEBUG_FALSE_BITS
508
509
510 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
511 uint32_t *bits) {
512 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
513
514 bool did_trans_retry = false; // only do thread_in_native_trans retry once
515 bool do_trans_retry; // flag to force the retry
516
517 *bits |= 0x00000001;
518
519 do {
520 do_trans_retry = false;
521
522 if (is_exiting()) {
523 // Thread is in the process of exiting. This is always checked
524 // first to reduce the risk of dereferencing a freed JavaThread.
525 *bits |= 0x00000100;
526 return false;
527 }
528
529 if (!is_external_suspend()) {
530 // Suspend request is cancelled. This is always checked before
531 // is_ext_suspended() to reduce the risk of a rogue resume
532 // confusing the thread that made the suspend request.
533 *bits |= 0x00000200;
534 return false;
535 }
536
537 if (is_ext_suspended()) {
538 // thread is suspended
539 *bits |= 0x00000400;
540 return true;
541 }
542
543 // Now that we no longer do hard suspends of threads running
544 // native code, the target thread can be changing thread state
545 // while we are in this routine:
546 //
547 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
548 //
549 // We save a copy of the thread state as observed at this moment
550 // and make our decision about suspend completeness based on the
551 // copy. This closes the race where the thread state is seen as
552 // _thread_in_native_trans in the if-thread_blocked check, but is
553 // seen as _thread_blocked in if-thread_in_native_trans check.
554 JavaThreadState save_state = thread_state();
555
556 if (save_state == _thread_blocked && is_suspend_equivalent()) {
557 // If the thread's state is _thread_blocked and this blocking
558 // condition is known to be equivalent to a suspend, then we can
559 // consider the thread to be externally suspended. This means that
560 // the code that sets _thread_blocked has been modified to do
561 // self-suspension if the blocking condition releases. We also
562 // used to check for CONDVAR_WAIT here, but that is now covered by
563 // the _thread_blocked with self-suspension check.
564 //
565 // Return true since we wouldn't be here unless there was still an
566 // external suspend request.
567 *bits |= 0x00001000;
568 return true;
569 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
570 // Threads running native code will self-suspend on native==>VM/Java
571 // transitions. If its stack is walkable (should always be the case
572 // unless this function is called before the actual java_suspend()
573 // call), then the wait is done.
574 *bits |= 0x00002000;
575 return true;
576 } else if (!called_by_wait && !did_trans_retry &&
577 save_state == _thread_in_native_trans &&
578 frame_anchor()->walkable()) {
579 // The thread is transitioning from thread_in_native to another
580 // thread state. check_safepoint_and_suspend_for_native_trans()
581 // will force the thread to self-suspend. If it hasn't gotten
582 // there yet we may have caught the thread in-between the native
583 // code check above and the self-suspend. Lucky us. If we were
584 // called by wait_for_ext_suspend_completion(), then it
585 // will be doing the retries so we don't have to.
586 //
587 // Since we use the saved thread state in the if-statement above,
588 // there is a chance that the thread has already transitioned to
589 // _thread_blocked by the time we get here. In that case, we will
590 // make a single unnecessary pass through the logic below. This
591 // doesn't hurt anything since we still do the trans retry.
592
593 *bits |= 0x00004000;
594
595 // Once the thread leaves thread_in_native_trans for another
596 // thread state, we break out of this retry loop. We shouldn't
597 // need this flag to prevent us from getting back here, but
598 // sometimes paranoia is good.
599 did_trans_retry = true;
600
601 // We wait for the thread to transition to a more usable state.
602 for (int i = 1; i <= SuspendRetryCount; i++) {
603 // We used to do an "os::yield_all(i)" call here with the intention
604 // that yielding would increase on each retry. However, the parameter
605 // is ignored on Linux which means the yield didn't scale up. Waiting
606 // on the SR_lock below provides a much more predictable scale up for
607 // the delay. It also provides a simple/direct point to check for any
608 // safepoint requests from the VMThread
609
610 // temporarily drops SR_lock while doing wait with safepoint check
611 // (if we're a JavaThread - the WatcherThread can also call this)
612 // and increase delay with each retry
613 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
614
615 // check the actual thread state instead of what we saved above
616 if (thread_state() != _thread_in_native_trans) {
617 // the thread has transitioned to another thread state so
618 // try all the checks (except this one) one more time.
619 do_trans_retry = true;
620 break;
621 }
622 } // end retry loop
623
624
625 }
626 } while (do_trans_retry);
627
628 *bits |= 0x00000010;
629 return false;
630 }
631
632 // Wait for an external suspend request to complete (or be cancelled).
633 // Returns true if the thread is externally suspended and false otherwise.
634 //
635 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
636 uint32_t *bits) {
637 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
638 false /* !called_by_wait */, bits);
639
640 // local flag copies to minimize SR_lock hold time
641 bool is_suspended;
642 bool pending;
643 uint32_t reset_bits;
644
645 // set a marker so is_ext_suspend_completed() knows we are the caller
646 *bits |= 0x00010000;
647
648 // We use reset_bits to reinitialize the bits value at the top of
649 // each retry loop. This allows the caller to make use of any
650 // unused bits for their own marking purposes.
651 reset_bits = *bits;
652
653 {
654 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
655 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
656 delay, bits);
657 pending = is_external_suspend();
658 }
659 // must release SR_lock to allow suspension to complete
660
661 if (!pending) {
662 // A cancelled suspend request is the only false return from
663 // is_ext_suspend_completed() that keeps us from entering the
664 // retry loop.
665 *bits |= 0x00020000;
666 return false;
667 }
668
669 if (is_suspended) {
670 *bits |= 0x00040000;
671 return true;
672 }
673
674 for (int i = 1; i <= retries; i++) {
675 *bits = reset_bits; // reinit to only track last retry
676
677 // We used to do an "os::yield_all(i)" call here with the intention
678 // that yielding would increase on each retry. However, the parameter
679 // is ignored on Linux which means the yield didn't scale up. Waiting
680 // on the SR_lock below provides a much more predictable scale up for
681 // the delay. It also provides a simple/direct point to check for any
682 // safepoint requests from the VMThread
683
684 {
685 MutexLocker ml(SR_lock());
686 // wait with safepoint check (if we're a JavaThread - the WatcherThread
687 // can also call this) and increase delay with each retry
688 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
689
690 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
691 delay, bits);
692
693 // It is possible for the external suspend request to be cancelled
694 // (by a resume) before the actual suspend operation is completed.
695 // Refresh our local copy to see if we still need to wait.
696 pending = is_external_suspend();
697 }
698
699 if (!pending) {
700 // A cancelled suspend request is the only false return from
701 // is_ext_suspend_completed() that keeps us from staying in the
702 // retry loop.
703 *bits |= 0x00080000;
704 return false;
705 }
706
707 if (is_suspended) {
708 *bits |= 0x00100000;
709 return true;
710 }
711 } // end retry loop
712
713 // thread did not suspend after all our retries
714 *bits |= 0x00200000;
715 return false;
716 }
717
718 #ifndef PRODUCT
719 void JavaThread::record_jump(address target, address instr, const char* file,
720 int line) {
721
722 // This should not need to be atomic as the only way for simultaneous
723 // updates is via interrupts. Even then this should be rare or non-existent
724 // and we don't care that much anyway.
725
726 int index = _jmp_ring_index;
727 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
728 _jmp_ring[index]._target = (intptr_t) target;
729 _jmp_ring[index]._instruction = (intptr_t) instr;
730 _jmp_ring[index]._file = file;
731 _jmp_ring[index]._line = line;
732 }
733 #endif // PRODUCT
734
735 // Called by flat profiler
736 // Callers have already called wait_for_ext_suspend_completion
737 // The assertion for that is currently too complex to put here:
738 bool JavaThread::profile_last_Java_frame(frame* _fr) {
739 bool gotframe = false;
740 // self suspension saves needed state.
741 if (has_last_Java_frame() && _anchor.walkable()) {
742 *_fr = pd_last_frame();
743 gotframe = true;
744 }
745 return gotframe;
746 }
747
748 void Thread::interrupt(Thread* thread) {
749 debug_only(check_for_dangling_thread_pointer(thread);)
750 os::interrupt(thread);
751 }
752
753 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
754 debug_only(check_for_dangling_thread_pointer(thread);)
755 // Note: If clear_interrupted==false, this simply fetches and
756 // returns the value of the field osthread()->interrupted().
757 return os::is_interrupted(thread, clear_interrupted);
758 }
759
760
761 // GC Support
762 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
763 jint thread_parity = _oops_do_parity;
764 if (thread_parity != strong_roots_parity) {
765 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
766 if (res == thread_parity) {
767 return true;
768 } else {
769 guarantee(res == strong_roots_parity, "Or else what?");
770 return false;
771 }
772 }
773 return false;
774 }
775
776 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
777 active_handles()->oops_do(f);
778 // Do oop for ThreadShadow
779 f->do_oop((oop*)&_pending_exception);
780 handle_area()->oops_do(f);
781 }
782
783 void Thread::nmethods_do(CodeBlobClosure* cf) {
784 // no nmethods in a generic thread...
785 }
786
787 void Thread::metadata_handles_do(void f(Metadata*)) {
788 // Only walk the Handles in Thread.
789 if (metadata_handles() != NULL) {
790 for (int i = 0; i< metadata_handles()->length(); i++) {
791 f(metadata_handles()->at(i));
792 }
793 }
794 }
795
796 void Thread::print_on(outputStream* st) const {
797 // get_priority assumes osthread initialized
798 if (osthread() != NULL) {
799 int os_prio;
800 if (os::get_native_priority(this, &os_prio) == OS_OK) {
801 st->print("os_prio=%d ", os_prio);
802 }
803 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
804 ext().print_on(st);
805 osthread()->print_on(st);
806 }
807 debug_only(if (WizardMode) print_owned_locks_on(st);)
808 }
809
810 // Thread::print_on_error() is called by fatal error handler. Don't use
811 // any lock or allocate memory.
812 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
813 if (is_VM_thread()) st->print("VMThread");
814 else if (is_Compiler_thread()) st->print("CompilerThread");
815 else if (is_Java_thread()) st->print("JavaThread");
816 else if (is_GC_task_thread()) st->print("GCTaskThread");
817 else if (is_Watcher_thread()) st->print("WatcherThread");
818 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
819 else st->print("Thread");
820
821 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
822 p2i(_stack_base - _stack_size), p2i(_stack_base));
823
824 if (osthread()) {
825 st->print(" [id=%d]", osthread()->thread_id());
826 }
827 }
828
829 #ifdef ASSERT
830 void Thread::print_owned_locks_on(outputStream* st) const {
831 Monitor *cur = _owned_locks;
832 if (cur == NULL) {
833 st->print(" (no locks) ");
834 } else {
835 st->print_cr(" Locks owned:");
836 while (cur) {
837 cur->print_on(st);
838 cur = cur->next();
839 }
840 }
841 }
842
843 static int ref_use_count = 0;
844
845 bool Thread::owns_locks_but_compiled_lock() const {
846 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
847 if (cur != Compile_lock) return true;
848 }
849 return false;
850 }
851
852
853 #endif
854
855 #ifndef PRODUCT
856
857 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
858 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
859 // no threads which allow_vm_block's are held
860 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
861 // Check if current thread is allowed to block at a safepoint
862 if (!(_allow_safepoint_count == 0)) {
863 fatal("Possible safepoint reached by thread that does not allow it");
864 }
865 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
866 fatal("LEAF method calling lock?");
867 }
868
869 #ifdef ASSERT
870 if (potential_vm_operation && is_Java_thread()
871 && !Universe::is_bootstrapping()) {
872 // Make sure we do not hold any locks that the VM thread also uses.
873 // This could potentially lead to deadlocks
874 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
875 // Threads_lock is special, since the safepoint synchronization will not start before this is
876 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
877 // since it is used to transfer control between JavaThreads and the VMThread
878 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
879 if ((cur->allow_vm_block() &&
880 cur != Threads_lock &&
881 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
882 cur != VMOperationRequest_lock &&
883 cur != VMOperationQueue_lock) ||
884 cur->rank() == Mutex::special) {
885 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
886 }
887 }
888 }
889
890 if (GCALotAtAllSafepoints) {
891 // We could enter a safepoint here and thus have a gc
892 InterfaceSupport::check_gc_alot();
893 }
894 #endif
895 }
896 #endif
897
898 bool Thread::is_in_stack(address adr) const {
899 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
900 address end = os::current_stack_pointer();
901 // Allow non Java threads to call this without stack_base
902 if (_stack_base == NULL) return true;
903 if (stack_base() >= adr && adr >= end) return true;
904
905 return false;
906 }
907
908
909 bool Thread::is_in_usable_stack(address adr) const {
910 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
911 size_t usable_stack_size = _stack_size - stack_guard_size;
912
913 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
914 }
915
916
917 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
918 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
919 // used for compilation in the future. If that change is made, the need for these methods
920 // should be revisited, and they should be removed if possible.
921
922 bool Thread::is_lock_owned(address adr) const {
923 return on_local_stack(adr);
924 }
925
926 bool Thread::set_as_starting_thread() {
927 // NOTE: this must be called inside the main thread.
928 return os::create_main_thread((JavaThread*)this);
929 }
930
931 static void initialize_class(Symbol* class_name, TRAPS) {
932 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
933 InstanceKlass::cast(klass)->initialize(CHECK);
934 }
935
936
937 // Creates the initial ThreadGroup
938 static Handle create_initial_thread_group(TRAPS) {
939 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
940 instanceKlassHandle klass (THREAD, k);
941
942 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
943 {
944 JavaValue result(T_VOID);
945 JavaCalls::call_special(&result,
946 system_instance,
947 klass,
948 vmSymbols::object_initializer_name(),
949 vmSymbols::void_method_signature(),
950 CHECK_NH);
951 }
952 Universe::set_system_thread_group(system_instance());
953
954 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
955 {
956 JavaValue result(T_VOID);
957 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
958 JavaCalls::call_special(&result,
959 main_instance,
960 klass,
961 vmSymbols::object_initializer_name(),
962 vmSymbols::threadgroup_string_void_signature(),
963 system_instance,
964 string,
965 CHECK_NH);
966 }
967 return main_instance;
968 }
969
970 // Creates the initial Thread
971 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
972 TRAPS) {
973 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
974 instanceKlassHandle klass (THREAD, k);
975 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
976
977 java_lang_Thread::set_thread(thread_oop(), thread);
978 java_lang_Thread::set_priority(thread_oop(), NormPriority);
979 thread->set_threadObj(thread_oop());
980
981 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
982
983 JavaValue result(T_VOID);
984 JavaCalls::call_special(&result, thread_oop,
985 klass,
986 vmSymbols::object_initializer_name(),
987 vmSymbols::threadgroup_string_void_signature(),
988 thread_group,
989 string,
990 CHECK_NULL);
991 return thread_oop();
992 }
993
994 static void call_initializeSystemClass(TRAPS) {
995 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
996 instanceKlassHandle klass (THREAD, k);
997
998 JavaValue result(T_VOID);
999 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1000 vmSymbols::void_method_signature(), CHECK);
1001 }
1002
1003 char java_runtime_name[128] = "";
1004 char java_runtime_version[128] = "";
1005
1006 // extract the JRE name from sun.misc.Version.java_runtime_name
1007 static const char* get_java_runtime_name(TRAPS) {
1008 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1009 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1010 fieldDescriptor fd;
1011 bool found = k != NULL &&
1012 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1013 vmSymbols::string_signature(), &fd);
1014 if (found) {
1015 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1016 if (name_oop == NULL) {
1017 return NULL;
1018 }
1019 const char* name = java_lang_String::as_utf8_string(name_oop,
1020 java_runtime_name,
1021 sizeof(java_runtime_name));
1022 return name;
1023 } else {
1024 return NULL;
1025 }
1026 }
1027
1028 // extract the JRE version from sun.misc.Version.java_runtime_version
1029 static const char* get_java_runtime_version(TRAPS) {
1030 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1031 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1032 fieldDescriptor fd;
1033 bool found = k != NULL &&
1034 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1035 vmSymbols::string_signature(), &fd);
1036 if (found) {
1037 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1038 if (name_oop == NULL) {
1039 return NULL;
1040 }
1041 const char* name = java_lang_String::as_utf8_string(name_oop,
1042 java_runtime_version,
1043 sizeof(java_runtime_version));
1044 return name;
1045 } else {
1046 return NULL;
1047 }
1048 }
1049
1050 // General purpose hook into Java code, run once when the VM is initialized.
1051 // The Java library method itself may be changed independently from the VM.
1052 static void call_postVMInitHook(TRAPS) {
1053 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1054 instanceKlassHandle klass (THREAD, k);
1055 if (klass.not_null()) {
1056 JavaValue result(T_VOID);
1057 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1058 vmSymbols::void_method_signature(),
1059 CHECK);
1060 }
1061 }
1062
1063 static void reset_vm_info_property(TRAPS) {
1064 // the vm info string
1065 ResourceMark rm(THREAD);
1066 const char *vm_info = VM_Version::vm_info_string();
1067
1068 // java.lang.System class
1069 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1070 instanceKlassHandle klass (THREAD, k);
1071
1072 // setProperty arguments
1073 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1074 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1075
1076 // return value
1077 JavaValue r(T_OBJECT);
1078
1079 // public static String setProperty(String key, String value);
1080 JavaCalls::call_static(&r,
1081 klass,
1082 vmSymbols::setProperty_name(),
1083 vmSymbols::string_string_string_signature(),
1084 key_str,
1085 value_str,
1086 CHECK);
1087 }
1088
1089
1090 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1091 bool daemon, TRAPS) {
1092 assert(thread_group.not_null(), "thread group should be specified");
1093 assert(threadObj() == NULL, "should only create Java thread object once");
1094
1095 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1096 instanceKlassHandle klass (THREAD, k);
1097 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1098
1099 java_lang_Thread::set_thread(thread_oop(), this);
1100 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1101 set_threadObj(thread_oop());
1102
1103 JavaValue result(T_VOID);
1104 if (thread_name != NULL) {
1105 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1106 // Thread gets assigned specified name and null target
1107 JavaCalls::call_special(&result,
1108 thread_oop,
1109 klass,
1110 vmSymbols::object_initializer_name(),
1111 vmSymbols::threadgroup_string_void_signature(),
1112 thread_group, // Argument 1
1113 name, // Argument 2
1114 THREAD);
1115 } else {
1116 // Thread gets assigned name "Thread-nnn" and null target
1117 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1118 JavaCalls::call_special(&result,
1119 thread_oop,
1120 klass,
1121 vmSymbols::object_initializer_name(),
1122 vmSymbols::threadgroup_runnable_void_signature(),
1123 thread_group, // Argument 1
1124 Handle(), // Argument 2
1125 THREAD);
1126 }
1127
1128
1129 if (daemon) {
1130 java_lang_Thread::set_daemon(thread_oop());
1131 }
1132
1133 if (HAS_PENDING_EXCEPTION) {
1134 return;
1135 }
1136
1137 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1138 Handle threadObj(THREAD, this->threadObj());
1139
1140 JavaCalls::call_special(&result,
1141 thread_group,
1142 group,
1143 vmSymbols::add_method_name(),
1144 vmSymbols::thread_void_signature(),
1145 threadObj, // Arg 1
1146 THREAD);
1147 }
1148
1149 // NamedThread -- non-JavaThread subclasses with multiple
1150 // uniquely named instances should derive from this.
1151 NamedThread::NamedThread() : Thread() {
1152 _name = NULL;
1153 _processed_thread = NULL;
1154 _gc_id = GCId::undefined();
1155 }
1156
1157 NamedThread::~NamedThread() {
1158 if (_name != NULL) {
1159 FREE_C_HEAP_ARRAY(char, _name);
1160 _name = NULL;
1161 }
1162 }
1163
1164 void NamedThread::set_name(const char* format, ...) {
1165 guarantee(_name == NULL, "Only get to set name once.");
1166 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1167 guarantee(_name != NULL, "alloc failure");
1168 va_list ap;
1169 va_start(ap, format);
1170 jio_vsnprintf(_name, max_name_len, format, ap);
1171 va_end(ap);
1172 }
1173
1174 void NamedThread::initialize_named_thread() {
1175 set_native_thread_name(name());
1176 }
1177
1178 void NamedThread::print_on(outputStream* st) const {
1179 st->print("\"%s\" ", name());
1180 Thread::print_on(st);
1181 st->cr();
1182 }
1183
1184
1185 // ======= WatcherThread ========
1186
1187 // The watcher thread exists to simulate timer interrupts. It should
1188 // be replaced by an abstraction over whatever native support for
1189 // timer interrupts exists on the platform.
1190
1191 WatcherThread* WatcherThread::_watcher_thread = NULL;
1192 bool WatcherThread::_startable = false;
1193 volatile bool WatcherThread::_should_terminate = false;
1194
1195 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1196 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1197 if (os::create_thread(this, os::watcher_thread)) {
1198 _watcher_thread = this;
1199
1200 // Set the watcher thread to the highest OS priority which should not be
1201 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1202 // is created. The only normal thread using this priority is the reference
1203 // handler thread, which runs for very short intervals only.
1204 // If the VMThread's priority is not lower than the WatcherThread profiling
1205 // will be inaccurate.
1206 os::set_priority(this, MaxPriority);
1207 if (!DisableStartThread) {
1208 os::start_thread(this);
1209 }
1210 }
1211 }
1212
1213 int WatcherThread::sleep() const {
1214 // The WatcherThread does not participate in the safepoint protocol
1215 // for the PeriodicTask_lock because it is not a JavaThread.
1216 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1217
1218 if (_should_terminate) {
1219 // check for termination before we do any housekeeping or wait
1220 return 0; // we did not sleep.
1221 }
1222
1223 // remaining will be zero if there are no tasks,
1224 // causing the WatcherThread to sleep until a task is
1225 // enrolled
1226 int remaining = PeriodicTask::time_to_wait();
1227 int time_slept = 0;
1228
1229 // we expect this to timeout - we only ever get unparked when
1230 // we should terminate or when a new task has been enrolled
1231 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1232
1233 jlong time_before_loop = os::javaTimeNanos();
1234
1235 while (true) {
1236 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1237 remaining);
1238 jlong now = os::javaTimeNanos();
1239
1240 if (remaining == 0) {
1241 // if we didn't have any tasks we could have waited for a long time
1242 // consider the time_slept zero and reset time_before_loop
1243 time_slept = 0;
1244 time_before_loop = now;
1245 } else {
1246 // need to recalculate since we might have new tasks in _tasks
1247 time_slept = (int) ((now - time_before_loop) / 1000000);
1248 }
1249
1250 // Change to task list or spurious wakeup of some kind
1251 if (timedout || _should_terminate) {
1252 break;
1253 }
1254
1255 remaining = PeriodicTask::time_to_wait();
1256 if (remaining == 0) {
1257 // Last task was just disenrolled so loop around and wait until
1258 // another task gets enrolled
1259 continue;
1260 }
1261
1262 remaining -= time_slept;
1263 if (remaining <= 0) {
1264 break;
1265 }
1266 }
1267
1268 return time_slept;
1269 }
1270
1271 void WatcherThread::run() {
1272 assert(this == watcher_thread(), "just checking");
1273
1274 this->record_stack_base_and_size();
1275 this->set_native_thread_name(this->name());
1276 this->set_active_handles(JNIHandleBlock::allocate_block());
1277 while (true) {
1278 assert(watcher_thread() == Thread::current(), "thread consistency check");
1279 assert(watcher_thread() == this, "thread consistency check");
1280
1281 // Calculate how long it'll be until the next PeriodicTask work
1282 // should be done, and sleep that amount of time.
1283 int time_waited = sleep();
1284
1285 if (is_error_reported()) {
1286 // A fatal error has happened, the error handler(VMError::report_and_die)
1287 // should abort JVM after creating an error log file. However in some
1288 // rare cases, the error handler itself might deadlock. Here we try to
1289 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1290 //
1291 // This code is in WatcherThread because WatcherThread wakes up
1292 // periodically so the fatal error handler doesn't need to do anything;
1293 // also because the WatcherThread is less likely to crash than other
1294 // threads.
1295
1296 for (;;) {
1297 if (!ShowMessageBoxOnError
1298 && (OnError == NULL || OnError[0] == '\0')
1299 && Arguments::abort_hook() == NULL) {
1300 os::sleep(this, ErrorLogTimeout * 60 * 1000, false);
1301 fdStream err(defaultStream::output_fd());
1302 err.print_raw_cr("# [ timer expired, abort... ]");
1303 // skip atexit/vm_exit/vm_abort hooks
1304 os::die();
1305 }
1306
1307 // Wake up 5 seconds later, the fatal handler may reset OnError or
1308 // ShowMessageBoxOnError when it is ready to abort.
1309 os::sleep(this, 5 * 1000, false);
1310 }
1311 }
1312
1313 if (_should_terminate) {
1314 // check for termination before posting the next tick
1315 break;
1316 }
1317
1318 PeriodicTask::real_time_tick(time_waited);
1319 }
1320
1321 // Signal that it is terminated
1322 {
1323 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1324 _watcher_thread = NULL;
1325 Terminator_lock->notify();
1326 }
1327 }
1328
1329 void WatcherThread::start() {
1330 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1331
1332 if (watcher_thread() == NULL && _startable) {
1333 _should_terminate = false;
1334 // Create the single instance of WatcherThread
1335 new WatcherThread();
1336 }
1337 }
1338
1339 void WatcherThread::make_startable() {
1340 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1341 _startable = true;
1342 }
1343
1344 void WatcherThread::stop() {
1345 {
1346 // Follow normal safepoint aware lock enter protocol since the
1347 // WatcherThread is stopped by another JavaThread.
1348 MutexLocker ml(PeriodicTask_lock);
1349 _should_terminate = true;
1350
1351 WatcherThread* watcher = watcher_thread();
1352 if (watcher != NULL) {
1353 // unpark the WatcherThread so it can see that it should terminate
1354 watcher->unpark();
1355 }
1356 }
1357
1358 MutexLocker mu(Terminator_lock);
1359
1360 while (watcher_thread() != NULL) {
1361 // This wait should make safepoint checks, wait without a timeout,
1362 // and wait as a suspend-equivalent condition.
1363 //
1364 // Note: If the FlatProfiler is running, then this thread is waiting
1365 // for the WatcherThread to terminate and the WatcherThread, via the
1366 // FlatProfiler task, is waiting for the external suspend request on
1367 // this thread to complete. wait_for_ext_suspend_completion() will
1368 // eventually timeout, but that takes time. Making this wait a
1369 // suspend-equivalent condition solves that timeout problem.
1370 //
1371 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1372 Mutex::_as_suspend_equivalent_flag);
1373 }
1374 }
1375
1376 void WatcherThread::unpark() {
1377 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1378 PeriodicTask_lock->notify();
1379 }
1380
1381 void WatcherThread::print_on(outputStream* st) const {
1382 st->print("\"%s\" ", name());
1383 Thread::print_on(st);
1384 st->cr();
1385 }
1386
1387 // ======= JavaThread ========
1388
1389 #if INCLUDE_JVMCI
1390
1391 jlong* JavaThread::_jvmci_old_thread_counters;
1392
1393 bool jvmci_counters_include(JavaThread* thread) {
1394 oop threadObj = thread->threadObj();
1395 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1396 }
1397
1398 void JavaThread::collect_counters(typeArrayOop array) {
1399 if (JVMCICounterSize > 0) {
1400 MutexLocker tl(Threads_lock);
1401 for (int i = 0; i < array->length(); i++) {
1402 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1403 }
1404 for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) {
1405 if (jvmci_counters_include(tp)) {
1406 for (int i = 0; i < array->length(); i++) {
1407 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1408 }
1409 }
1410 }
1411 }
1412 }
1413
1414 #endif // INCLUDE_JVMCI
1415
1416 // A JavaThread is a normal Java thread
1417
1418 void JavaThread::initialize() {
1419 // Initialize fields
1420
1421 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1422 set_claimed_par_id(UINT_MAX);
1423
1424 set_saved_exception_pc(NULL);
1425 set_threadObj(NULL);
1426 _anchor.clear();
1427 set_entry_point(NULL);
1428 set_jni_functions(jni_functions());
1429 set_callee_target(NULL);
1430 set_vm_result(NULL);
1431 set_vm_result_2(NULL);
1432 set_vframe_array_head(NULL);
1433 set_vframe_array_last(NULL);
1434 set_deferred_locals(NULL);
1435 set_deopt_mark(NULL);
1436 set_deopt_nmethod(NULL);
1437 clear_must_deopt_id();
1438 set_monitor_chunks(NULL);
1439 set_next(NULL);
1440 set_thread_state(_thread_new);
1441 _terminated = _not_terminated;
1442 _privileged_stack_top = NULL;
1443 _array_for_gc = NULL;
1444 _suspend_equivalent = false;
1445 _in_deopt_handler = 0;
1446 _doing_unsafe_access = false;
1447 _stack_guard_state = stack_guard_unused;
1448 #if INCLUDE_JVMCI
1449 _pending_monitorenter = false;
1450 _pending_deoptimization = -1;
1451 _pending_failed_speculation = NULL;
1452 _pending_transfer_to_interpreter = false;
1453 _jvmci._alternate_call_target = NULL;
1454 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1455 if (JVMCICounterSize > 0) {
1456 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1457 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1458 } else {
1459 _jvmci_counters = NULL;
1460 }
1461 #endif // INCLUDE_JVMCI
1462 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1463 _exception_pc = 0;
1464 _exception_handler_pc = 0;
1465 _is_method_handle_return = 0;
1466 _jvmti_thread_state= NULL;
1467 _should_post_on_exceptions_flag = JNI_FALSE;
1468 _jvmti_get_loaded_classes_closure = NULL;
1469 _interp_only_mode = 0;
1470 _special_runtime_exit_condition = _no_async_condition;
1471 _pending_async_exception = NULL;
1472 _thread_stat = NULL;
1473 _thread_stat = new ThreadStatistics();
1474 _blocked_on_compilation = false;
1475 _jni_active_critical = 0;
1476 _pending_jni_exception_check_fn = NULL;
1477 _do_not_unlock_if_synchronized = false;
1478 _cached_monitor_info = NULL;
1479 _parker = Parker::Allocate(this);
1480
1481 #ifndef PRODUCT
1482 _jmp_ring_index = 0;
1483 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1484 record_jump(NULL, NULL, NULL, 0);
1485 }
1486 #endif // PRODUCT
1487
1488 set_thread_profiler(NULL);
1489 if (FlatProfiler::is_active()) {
1490 // This is where we would decide to either give each thread it's own profiler
1491 // or use one global one from FlatProfiler,
1492 // or up to some count of the number of profiled threads, etc.
1493 ThreadProfiler* pp = new ThreadProfiler();
1494 pp->engage();
1495 set_thread_profiler(pp);
1496 }
1497
1498 // Setup safepoint state info for this thread
1499 ThreadSafepointState::create(this);
1500
1501 debug_only(_java_call_counter = 0);
1502
1503 // JVMTI PopFrame support
1504 _popframe_condition = popframe_inactive;
1505 _popframe_preserved_args = NULL;
1506 _popframe_preserved_args_size = 0;
1507 _frames_to_pop_failed_realloc = 0;
1508
1509 pd_initialize();
1510 }
1511
1512 #if INCLUDE_ALL_GCS
1513 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1514 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1515 #endif // INCLUDE_ALL_GCS
1516
1517 JavaThread::JavaThread(bool is_attaching_via_jni) :
1518 Thread()
1519 #if INCLUDE_ALL_GCS
1520 , _satb_mark_queue(&_satb_mark_queue_set),
1521 _dirty_card_queue(&_dirty_card_queue_set)
1522 #endif // INCLUDE_ALL_GCS
1523 {
1524 initialize();
1525 if (is_attaching_via_jni) {
1526 _jni_attach_state = _attaching_via_jni;
1527 } else {
1528 _jni_attach_state = _not_attaching_via_jni;
1529 }
1530 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1531 }
1532
1533 bool JavaThread::reguard_stack(address cur_sp) {
1534 if (_stack_guard_state != stack_guard_yellow_disabled) {
1535 return true; // Stack already guarded or guard pages not needed.
1536 }
1537
1538 if (register_stack_overflow()) {
1539 // For those architectures which have separate register and
1540 // memory stacks, we must check the register stack to see if
1541 // it has overflowed.
1542 return false;
1543 }
1544
1545 // Java code never executes within the yellow zone: the latter is only
1546 // there to provoke an exception during stack banging. If java code
1547 // is executing there, either StackShadowPages should be larger, or
1548 // some exception code in c1, c2 or the interpreter isn't unwinding
1549 // when it should.
1550 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1551
1552 enable_stack_yellow_zone();
1553 return true;
1554 }
1555
1556 bool JavaThread::reguard_stack(void) {
1557 return reguard_stack(os::current_stack_pointer());
1558 }
1559
1560
1561 void JavaThread::block_if_vm_exited() {
1562 if (_terminated == _vm_exited) {
1563 // _vm_exited is set at safepoint, and Threads_lock is never released
1564 // we will block here forever
1565 Threads_lock->lock_without_safepoint_check();
1566 ShouldNotReachHere();
1567 }
1568 }
1569
1570
1571 // Remove this ifdef when C1 is ported to the compiler interface.
1572 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1573 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1574
1575 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1576 Thread()
1577 #if INCLUDE_ALL_GCS
1578 , _satb_mark_queue(&_satb_mark_queue_set),
1579 _dirty_card_queue(&_dirty_card_queue_set)
1580 #endif // INCLUDE_ALL_GCS
1581 {
1582 initialize();
1583 _jni_attach_state = _not_attaching_via_jni;
1584 set_entry_point(entry_point);
1585 // Create the native thread itself.
1586 // %note runtime_23
1587 os::ThreadType thr_type = os::java_thread;
1588 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1589 os::java_thread;
1590 os::create_thread(this, thr_type, stack_sz);
1591 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1592 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1593 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1594 // the exception consists of creating the exception object & initializing it, initialization
1595 // will leave the VM via a JavaCall and then all locks must be unlocked).
1596 //
1597 // The thread is still suspended when we reach here. Thread must be explicit started
1598 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1599 // by calling Threads:add. The reason why this is not done here, is because the thread
1600 // object must be fully initialized (take a look at JVM_Start)
1601 }
1602
1603 JavaThread::~JavaThread() {
1604
1605 // JSR166 -- return the parker to the free list
1606 Parker::Release(_parker);
1607 _parker = NULL;
1608
1609 // Free any remaining previous UnrollBlock
1610 vframeArray* old_array = vframe_array_last();
1611
1612 if (old_array != NULL) {
1613 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1614 old_array->set_unroll_block(NULL);
1615 delete old_info;
1616 delete old_array;
1617 }
1618
1619 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1620 if (deferred != NULL) {
1621 // This can only happen if thread is destroyed before deoptimization occurs.
1622 assert(deferred->length() != 0, "empty array!");
1623 do {
1624 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1625 deferred->remove_at(0);
1626 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1627 delete dlv;
1628 } while (deferred->length() != 0);
1629 delete deferred;
1630 }
1631
1632 // All Java related clean up happens in exit
1633 ThreadSafepointState::destroy(this);
1634 if (_thread_profiler != NULL) delete _thread_profiler;
1635 if (_thread_stat != NULL) delete _thread_stat;
1636
1637 #if INCLUDE_JVMCI
1638 if (JVMCICounterSize > 0) {
1639 if (jvmci_counters_include(this)) {
1640 for (int i = 0; i < JVMCICounterSize; i++) {
1641 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1642 }
1643 }
1644 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1645 }
1646 #endif // INCLUDE_JVMCI
1647 }
1648
1649
1650 // The first routine called by a new Java thread
1651 void JavaThread::run() {
1652 // initialize thread-local alloc buffer related fields
1653 this->initialize_tlab();
1654
1655 // used to test validity of stack trace backs
1656 this->record_base_of_stack_pointer();
1657
1658 // Record real stack base and size.
1659 this->record_stack_base_and_size();
1660
1661 this->create_stack_guard_pages();
1662
1663 this->cache_global_variables();
1664
1665 // Thread is now sufficient initialized to be handled by the safepoint code as being
1666 // in the VM. Change thread state from _thread_new to _thread_in_vm
1667 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1668
1669 assert(JavaThread::current() == this, "sanity check");
1670 assert(!Thread::current()->owns_locks(), "sanity check");
1671
1672 DTRACE_THREAD_PROBE(start, this);
1673
1674 // This operation might block. We call that after all safepoint checks for a new thread has
1675 // been completed.
1676 this->set_active_handles(JNIHandleBlock::allocate_block());
1677
1678 if (JvmtiExport::should_post_thread_life()) {
1679 JvmtiExport::post_thread_start(this);
1680 }
1681
1682 EventThreadStart event;
1683 if (event.should_commit()) {
1684 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1685 event.commit();
1686 }
1687
1688 // We call another function to do the rest so we are sure that the stack addresses used
1689 // from there will be lower than the stack base just computed
1690 thread_main_inner();
1691
1692 // Note, thread is no longer valid at this point!
1693 }
1694
1695
1696 void JavaThread::thread_main_inner() {
1697 assert(JavaThread::current() == this, "sanity check");
1698 assert(this->threadObj() != NULL, "just checking");
1699
1700 // Execute thread entry point unless this thread has a pending exception
1701 // or has been stopped before starting.
1702 // Note: Due to JVM_StopThread we can have pending exceptions already!
1703 if (!this->has_pending_exception() &&
1704 !java_lang_Thread::is_stillborn(this->threadObj())) {
1705 {
1706 ResourceMark rm(this);
1707 this->set_native_thread_name(this->get_thread_name());
1708 }
1709 HandleMark hm(this);
1710 this->entry_point()(this, this);
1711 }
1712
1713 DTRACE_THREAD_PROBE(stop, this);
1714
1715 this->exit(false);
1716 delete this;
1717 }
1718
1719
1720 static void ensure_join(JavaThread* thread) {
1721 // We do not need to grap the Threads_lock, since we are operating on ourself.
1722 Handle threadObj(thread, thread->threadObj());
1723 assert(threadObj.not_null(), "java thread object must exist");
1724 ObjectLocker lock(threadObj, thread);
1725 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1726 thread->clear_pending_exception();
1727 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1728 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1729 // Clear the native thread instance - this makes isAlive return false and allows the join()
1730 // to complete once we've done the notify_all below
1731 java_lang_Thread::set_thread(threadObj(), NULL);
1732 lock.notify_all(thread);
1733 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1734 thread->clear_pending_exception();
1735 }
1736
1737
1738 // For any new cleanup additions, please check to see if they need to be applied to
1739 // cleanup_failed_attach_current_thread as well.
1740 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1741 assert(this == JavaThread::current(), "thread consistency check");
1742
1743 HandleMark hm(this);
1744 Handle uncaught_exception(this, this->pending_exception());
1745 this->clear_pending_exception();
1746 Handle threadObj(this, this->threadObj());
1747 assert(threadObj.not_null(), "Java thread object should be created");
1748
1749 if (get_thread_profiler() != NULL) {
1750 get_thread_profiler()->disengage();
1751 ResourceMark rm;
1752 get_thread_profiler()->print(get_thread_name());
1753 }
1754
1755
1756 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1757 {
1758 EXCEPTION_MARK;
1759
1760 CLEAR_PENDING_EXCEPTION;
1761 }
1762 if (!destroy_vm) {
1763 if (uncaught_exception.not_null()) {
1764 EXCEPTION_MARK;
1765 // Call method Thread.dispatchUncaughtException().
1766 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1767 JavaValue result(T_VOID);
1768 JavaCalls::call_virtual(&result,
1769 threadObj, thread_klass,
1770 vmSymbols::dispatchUncaughtException_name(),
1771 vmSymbols::throwable_void_signature(),
1772 uncaught_exception,
1773 THREAD);
1774 if (HAS_PENDING_EXCEPTION) {
1775 ResourceMark rm(this);
1776 jio_fprintf(defaultStream::error_stream(),
1777 "\nException: %s thrown from the UncaughtExceptionHandler"
1778 " in thread \"%s\"\n",
1779 pending_exception()->klass()->external_name(),
1780 get_thread_name());
1781 CLEAR_PENDING_EXCEPTION;
1782 }
1783 }
1784
1785 // Called before the java thread exit since we want to read info
1786 // from java_lang_Thread object
1787 EventThreadEnd event;
1788 if (event.should_commit()) {
1789 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1790 event.commit();
1791 }
1792
1793 // Call after last event on thread
1794 EVENT_THREAD_EXIT(this);
1795
1796 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1797 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1798 // is deprecated anyhow.
1799 if (!is_Compiler_thread()) {
1800 int count = 3;
1801 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1802 EXCEPTION_MARK;
1803 JavaValue result(T_VOID);
1804 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1805 JavaCalls::call_virtual(&result,
1806 threadObj, thread_klass,
1807 vmSymbols::exit_method_name(),
1808 vmSymbols::void_method_signature(),
1809 THREAD);
1810 CLEAR_PENDING_EXCEPTION;
1811 }
1812 }
1813 // notify JVMTI
1814 if (JvmtiExport::should_post_thread_life()) {
1815 JvmtiExport::post_thread_end(this);
1816 }
1817
1818 // We have notified the agents that we are exiting, before we go on,
1819 // we must check for a pending external suspend request and honor it
1820 // in order to not surprise the thread that made the suspend request.
1821 while (true) {
1822 {
1823 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1824 if (!is_external_suspend()) {
1825 set_terminated(_thread_exiting);
1826 ThreadService::current_thread_exiting(this);
1827 break;
1828 }
1829 // Implied else:
1830 // Things get a little tricky here. We have a pending external
1831 // suspend request, but we are holding the SR_lock so we
1832 // can't just self-suspend. So we temporarily drop the lock
1833 // and then self-suspend.
1834 }
1835
1836 ThreadBlockInVM tbivm(this);
1837 java_suspend_self();
1838
1839 // We're done with this suspend request, but we have to loop around
1840 // and check again. Eventually we will get SR_lock without a pending
1841 // external suspend request and will be able to mark ourselves as
1842 // exiting.
1843 }
1844 // no more external suspends are allowed at this point
1845 } else {
1846 // before_exit() has already posted JVMTI THREAD_END events
1847 }
1848
1849 // Notify waiters on thread object. This has to be done after exit() is called
1850 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1851 // group should have the destroyed bit set before waiters are notified).
1852 ensure_join(this);
1853 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1854
1855 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1856 // held by this thread must be released. The spec does not distinguish
1857 // between JNI-acquired and regular Java monitors. We can only see
1858 // regular Java monitors here if monitor enter-exit matching is broken.
1859 //
1860 // Optionally release any monitors for regular JavaThread exits. This
1861 // is provided as a work around for any bugs in monitor enter-exit
1862 // matching. This can be expensive so it is not enabled by default.
1863 //
1864 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1865 // ObjectSynchronizer::release_monitors_owned_by_thread().
1866 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
1867 // Sanity check even though JNI DetachCurrentThread() would have
1868 // returned JNI_ERR if there was a Java frame. JavaThread exit
1869 // should be done executing Java code by the time we get here.
1870 assert(!this->has_last_Java_frame(),
1871 "should not have a Java frame when detaching or exiting");
1872 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1873 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1874 }
1875
1876 // These things needs to be done while we are still a Java Thread. Make sure that thread
1877 // is in a consistent state, in case GC happens
1878 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1879
1880 if (active_handles() != NULL) {
1881 JNIHandleBlock* block = active_handles();
1882 set_active_handles(NULL);
1883 JNIHandleBlock::release_block(block);
1884 }
1885
1886 if (free_handle_block() != NULL) {
1887 JNIHandleBlock* block = free_handle_block();
1888 set_free_handle_block(NULL);
1889 JNIHandleBlock::release_block(block);
1890 }
1891
1892 // These have to be removed while this is still a valid thread.
1893 remove_stack_guard_pages();
1894
1895 if (UseTLAB) {
1896 tlab().make_parsable(true); // retire TLAB
1897 }
1898
1899 if (JvmtiEnv::environments_might_exist()) {
1900 JvmtiExport::cleanup_thread(this);
1901 }
1902
1903 // We must flush any deferred card marks before removing a thread from
1904 // the list of active threads.
1905 Universe::heap()->flush_deferred_store_barrier(this);
1906 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1907
1908 #if INCLUDE_ALL_GCS
1909 // We must flush the G1-related buffers before removing a thread
1910 // from the list of active threads. We must do this after any deferred
1911 // card marks have been flushed (above) so that any entries that are
1912 // added to the thread's dirty card queue as a result are not lost.
1913 if (UseG1GC) {
1914 flush_barrier_queues();
1915 }
1916 #endif // INCLUDE_ALL_GCS
1917
1918 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1919 Threads::remove(this);
1920 }
1921
1922 #if INCLUDE_ALL_GCS
1923 // Flush G1-related queues.
1924 void JavaThread::flush_barrier_queues() {
1925 satb_mark_queue().flush();
1926 dirty_card_queue().flush();
1927 }
1928
1929 void JavaThread::initialize_queues() {
1930 assert(!SafepointSynchronize::is_at_safepoint(),
1931 "we should not be at a safepoint");
1932
1933 ObjPtrQueue& satb_queue = satb_mark_queue();
1934 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1935 // The SATB queue should have been constructed with its active
1936 // field set to false.
1937 assert(!satb_queue.is_active(), "SATB queue should not be active");
1938 assert(satb_queue.is_empty(), "SATB queue should be empty");
1939 // If we are creating the thread during a marking cycle, we should
1940 // set the active field of the SATB queue to true.
1941 if (satb_queue_set.is_active()) {
1942 satb_queue.set_active(true);
1943 }
1944
1945 DirtyCardQueue& dirty_queue = dirty_card_queue();
1946 // The dirty card queue should have been constructed with its
1947 // active field set to true.
1948 assert(dirty_queue.is_active(), "dirty card queue should be active");
1949 }
1950 #endif // INCLUDE_ALL_GCS
1951
1952 void JavaThread::cleanup_failed_attach_current_thread() {
1953 if (get_thread_profiler() != NULL) {
1954 get_thread_profiler()->disengage();
1955 ResourceMark rm;
1956 get_thread_profiler()->print(get_thread_name());
1957 }
1958
1959 if (active_handles() != NULL) {
1960 JNIHandleBlock* block = active_handles();
1961 set_active_handles(NULL);
1962 JNIHandleBlock::release_block(block);
1963 }
1964
1965 if (free_handle_block() != NULL) {
1966 JNIHandleBlock* block = free_handle_block();
1967 set_free_handle_block(NULL);
1968 JNIHandleBlock::release_block(block);
1969 }
1970
1971 // These have to be removed while this is still a valid thread.
1972 remove_stack_guard_pages();
1973
1974 if (UseTLAB) {
1975 tlab().make_parsable(true); // retire TLAB, if any
1976 }
1977
1978 #if INCLUDE_ALL_GCS
1979 if (UseG1GC) {
1980 flush_barrier_queues();
1981 }
1982 #endif // INCLUDE_ALL_GCS
1983
1984 Threads::remove(this);
1985 delete this;
1986 }
1987
1988
1989
1990
1991 JavaThread* JavaThread::active() {
1992 Thread* thread = Thread::current();
1993 assert(thread != NULL, "just checking");
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 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2926 // ThreadGroup.name can be null
2927 if (name != NULL) {
2928 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2929 return str;
2930 }
2931 }
2932 }
2933 return NULL;
2934 }
2935
2936 const char* JavaThread::get_parent_name() const {
2937 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2938 oop thread_obj = threadObj();
2939 if (thread_obj != NULL) {
2940 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2941 if (thread_group != NULL) {
2942 oop parent = java_lang_ThreadGroup::parent(thread_group);
2943 if (parent != NULL) {
2944 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2945 // ThreadGroup.name can be null
2946 if (name != NULL) {
2947 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2948 return str;
2949 }
2950 }
2951 }
2952 }
2953 return NULL;
2954 }
2955
2956 ThreadPriority JavaThread::java_priority() const {
2957 oop thr_oop = threadObj();
2958 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2959 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2960 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2961 return priority;
2962 }
2963
2964 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2965
2966 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2967 // Link Java Thread object <-> C++ Thread
2968
2969 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2970 // and put it into a new Handle. The Handle "thread_oop" can then
2971 // be used to pass the C++ thread object to other methods.
2972
2973 // Set the Java level thread object (jthread) field of the
2974 // new thread (a JavaThread *) to C++ thread object using the
2975 // "thread_oop" handle.
2976
2977 // Set the thread field (a JavaThread *) of the
2978 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2979
2980 Handle thread_oop(Thread::current(),
2981 JNIHandles::resolve_non_null(jni_thread));
2982 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2983 "must be initialized");
2984 set_threadObj(thread_oop());
2985 java_lang_Thread::set_thread(thread_oop(), this);
2986
2987 if (prio == NoPriority) {
2988 prio = java_lang_Thread::priority(thread_oop());
2989 assert(prio != NoPriority, "A valid priority should be present");
2990 }
2991
2992 // Push the Java priority down to the native thread; needs Threads_lock
2993 Thread::set_priority(this, prio);
2994
2995 prepare_ext();
2996
2997 // Add the new thread to the Threads list and set it in motion.
2998 // We must have threads lock in order to call Threads::add.
2999 // It is crucial that we do not block before the thread is
3000 // added to the Threads list for if a GC happens, then the java_thread oop
3001 // will not be visited by GC.
3002 Threads::add(this);
3003 }
3004
3005 oop JavaThread::current_park_blocker() {
3006 // Support for JSR-166 locks
3007 oop thread_oop = threadObj();
3008 if (thread_oop != NULL &&
3009 JDK_Version::current().supports_thread_park_blocker()) {
3010 return java_lang_Thread::park_blocker(thread_oop);
3011 }
3012 return NULL;
3013 }
3014
3015
3016 void JavaThread::print_stack_on(outputStream* st) {
3017 if (!has_last_Java_frame()) return;
3018 ResourceMark rm;
3019 HandleMark hm;
3020
3021 RegisterMap reg_map(this);
3022 vframe* start_vf = last_java_vframe(®_map);
3023 int count = 0;
3024 for (vframe* f = start_vf; f; f = f->sender()) {
3025 if (f->is_java_frame()) {
3026 javaVFrame* jvf = javaVFrame::cast(f);
3027 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3028
3029 // Print out lock information
3030 if (JavaMonitorsInStackTrace) {
3031 jvf->print_lock_info_on(st, count);
3032 }
3033 } else {
3034 // Ignore non-Java frames
3035 }
3036
3037 // Bail-out case for too deep stacks
3038 count++;
3039 if (MaxJavaStackTraceDepth == count) return;
3040 }
3041 }
3042
3043
3044 // JVMTI PopFrame support
3045 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3046 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3047 if (in_bytes(size_in_bytes) != 0) {
3048 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3049 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3050 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3051 }
3052 }
3053
3054 void* JavaThread::popframe_preserved_args() {
3055 return _popframe_preserved_args;
3056 }
3057
3058 ByteSize JavaThread::popframe_preserved_args_size() {
3059 return in_ByteSize(_popframe_preserved_args_size);
3060 }
3061
3062 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3063 int sz = in_bytes(popframe_preserved_args_size());
3064 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3065 return in_WordSize(sz / wordSize);
3066 }
3067
3068 void JavaThread::popframe_free_preserved_args() {
3069 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3070 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3071 _popframe_preserved_args = NULL;
3072 _popframe_preserved_args_size = 0;
3073 }
3074
3075 #ifndef PRODUCT
3076
3077 void JavaThread::trace_frames() {
3078 tty->print_cr("[Describe stack]");
3079 int frame_no = 1;
3080 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3081 tty->print(" %d. ", frame_no++);
3082 fst.current()->print_value_on(tty, this);
3083 tty->cr();
3084 }
3085 }
3086
3087 class PrintAndVerifyOopClosure: public OopClosure {
3088 protected:
3089 template <class T> inline void do_oop_work(T* p) {
3090 oop obj = oopDesc::load_decode_heap_oop(p);
3091 if (obj == NULL) return;
3092 tty->print(INTPTR_FORMAT ": ", p2i(p));
3093 if (obj->is_oop_or_null()) {
3094 if (obj->is_objArray()) {
3095 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3096 } else {
3097 obj->print();
3098 }
3099 } else {
3100 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3101 }
3102 tty->cr();
3103 }
3104 public:
3105 virtual void do_oop(oop* p) { do_oop_work(p); }
3106 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3107 };
3108
3109
3110 static void oops_print(frame* f, const RegisterMap *map) {
3111 PrintAndVerifyOopClosure print;
3112 f->print_value();
3113 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3114 }
3115
3116 // Print our all the locations that contain oops and whether they are
3117 // valid or not. This useful when trying to find the oldest frame
3118 // where an oop has gone bad since the frame walk is from youngest to
3119 // oldest.
3120 void JavaThread::trace_oops() {
3121 tty->print_cr("[Trace oops]");
3122 frames_do(oops_print);
3123 }
3124
3125
3126 #ifdef ASSERT
3127 // Print or validate the layout of stack frames
3128 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3129 ResourceMark rm;
3130 PRESERVE_EXCEPTION_MARK;
3131 FrameValues values;
3132 int frame_no = 0;
3133 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3134 fst.current()->describe(values, ++frame_no);
3135 if (depth == frame_no) break;
3136 }
3137 if (validate_only) {
3138 values.validate();
3139 } else {
3140 tty->print_cr("[Describe stack layout]");
3141 values.print(this);
3142 }
3143 }
3144 #endif
3145
3146 void JavaThread::trace_stack_from(vframe* start_vf) {
3147 ResourceMark rm;
3148 int vframe_no = 1;
3149 for (vframe* f = start_vf; f; f = f->sender()) {
3150 if (f->is_java_frame()) {
3151 javaVFrame::cast(f)->print_activation(vframe_no++);
3152 } else {
3153 f->print();
3154 }
3155 if (vframe_no > StackPrintLimit) {
3156 tty->print_cr("...<more frames>...");
3157 return;
3158 }
3159 }
3160 }
3161
3162
3163 void JavaThread::trace_stack() {
3164 if (!has_last_Java_frame()) return;
3165 ResourceMark rm;
3166 HandleMark hm;
3167 RegisterMap reg_map(this);
3168 trace_stack_from(last_java_vframe(®_map));
3169 }
3170
3171
3172 #endif // PRODUCT
3173
3174
3175 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3176 assert(reg_map != NULL, "a map must be given");
3177 frame f = last_frame();
3178 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3179 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3180 }
3181 return NULL;
3182 }
3183
3184
3185 Klass* JavaThread::security_get_caller_class(int depth) {
3186 vframeStream vfst(this);
3187 vfst.security_get_caller_frame(depth);
3188 if (!vfst.at_end()) {
3189 return vfst.method()->method_holder();
3190 }
3191 return NULL;
3192 }
3193
3194 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3195 assert(thread->is_Compiler_thread(), "must be compiler thread");
3196 CompileBroker::compiler_thread_loop();
3197 }
3198
3199 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3200 NMethodSweeper::sweeper_loop();
3201 }
3202
3203 // Create a CompilerThread
3204 CompilerThread::CompilerThread(CompileQueue* queue,
3205 CompilerCounters* counters)
3206 : JavaThread(&compiler_thread_entry) {
3207 _env = NULL;
3208 _log = NULL;
3209 _task = NULL;
3210 _queue = queue;
3211 _counters = counters;
3212 _buffer_blob = NULL;
3213 _compiler = NULL;
3214
3215 #ifndef PRODUCT
3216 _ideal_graph_printer = NULL;
3217 #endif
3218 }
3219
3220 bool CompilerThread::can_call_java() const {
3221 return _compiler != NULL && _compiler->is_jvmci();
3222 }
3223
3224 // Create sweeper thread
3225 CodeCacheSweeperThread::CodeCacheSweeperThread()
3226 : JavaThread(&sweeper_thread_entry) {
3227 _scanned_nmethod = NULL;
3228 }
3229 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3230 JavaThread::oops_do(f, cld_f, cf);
3231 if (_scanned_nmethod != NULL && cf != NULL) {
3232 // Safepoints can occur when the sweeper is scanning an nmethod so
3233 // process it here to make sure it isn't unloaded in the middle of
3234 // a scan.
3235 cf->do_code_blob(_scanned_nmethod);
3236 }
3237 }
3238
3239
3240 // ======= Threads ========
3241
3242 // The Threads class links together all active threads, and provides
3243 // operations over all threads. It is protected by its own Mutex
3244 // lock, which is also used in other contexts to protect thread
3245 // operations from having the thread being operated on from exiting
3246 // and going away unexpectedly (e.g., safepoint synchronization)
3247
3248 JavaThread* Threads::_thread_list = NULL;
3249 int Threads::_number_of_threads = 0;
3250 int Threads::_number_of_non_daemon_threads = 0;
3251 int Threads::_return_code = 0;
3252 int Threads::_thread_claim_parity = 0;
3253 size_t JavaThread::_stack_size_at_create = 0;
3254 #ifdef ASSERT
3255 bool Threads::_vm_complete = false;
3256 #endif
3257
3258 // All JavaThreads
3259 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3260
3261 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3262 void Threads::threads_do(ThreadClosure* tc) {
3263 assert_locked_or_safepoint(Threads_lock);
3264 // ALL_JAVA_THREADS iterates through all JavaThreads
3265 ALL_JAVA_THREADS(p) {
3266 tc->do_thread(p);
3267 }
3268 // Someday we could have a table or list of all non-JavaThreads.
3269 // For now, just manually iterate through them.
3270 tc->do_thread(VMThread::vm_thread());
3271 Universe::heap()->gc_threads_do(tc);
3272 WatcherThread *wt = WatcherThread::watcher_thread();
3273 // Strictly speaking, the following NULL check isn't sufficient to make sure
3274 // the data for WatcherThread is still valid upon being examined. However,
3275 // considering that WatchThread terminates when the VM is on the way to
3276 // exit at safepoint, the chance of the above is extremely small. The right
3277 // way to prevent termination of WatcherThread would be to acquire
3278 // Terminator_lock, but we can't do that without violating the lock rank
3279 // checking in some cases.
3280 if (wt != NULL) {
3281 tc->do_thread(wt);
3282 }
3283
3284 // If CompilerThreads ever become non-JavaThreads, add them here
3285 }
3286
3287 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3288 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3289
3290 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3291 create_vm_init_libraries();
3292 }
3293
3294 initialize_class(vmSymbols::java_lang_String(), CHECK);
3295
3296 // Initialize java_lang.System (needed before creating the thread)
3297 initialize_class(vmSymbols::java_lang_System(), CHECK);
3298 // The VM creates & returns objects of this class. Make sure it's initialized.
3299 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3300 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3301 Handle thread_group = create_initial_thread_group(CHECK);
3302 Universe::set_main_thread_group(thread_group());
3303 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3304 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3305 main_thread->set_threadObj(thread_object);
3306 // Set thread status to running since main thread has
3307 // been started and running.
3308 java_lang_Thread::set_thread_status(thread_object,
3309 java_lang_Thread::RUNNABLE);
3310
3311 // The VM preresolves methods to these classes. Make sure that they get initialized
3312 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3313 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3314 call_initializeSystemClass(CHECK);
3315
3316 // get the Java runtime name after java.lang.System is initialized
3317 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3318 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3319
3320 // an instance of OutOfMemory exception has been allocated earlier
3321 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3322 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3323 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3324 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3325 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3326 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3327 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3328 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3329 }
3330
3331 void Threads::initialize_jsr292_core_classes(TRAPS) {
3332 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3333 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3334 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3335 }
3336
3337 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3338 extern void JDK_Version_init();
3339
3340 // Preinitialize version info.
3341 VM_Version::early_initialize();
3342
3343 // Check version
3344 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3345
3346 // Initialize the output stream module
3347 ostream_init();
3348
3349 // Process java launcher properties.
3350 Arguments::process_sun_java_launcher_properties(args);
3351
3352 // Initialize the os module before using TLS
3353 os::init();
3354
3355 // Record VM creation timing statistics
3356 TraceVmCreationTime create_vm_timer;
3357 create_vm_timer.start();
3358
3359 // Initialize system properties.
3360 Arguments::init_system_properties();
3361
3362 // So that JDK version can be used as a discriminator when parsing arguments
3363 JDK_Version_init();
3364
3365 // Update/Initialize System properties after JDK version number is known
3366 Arguments::init_version_specific_system_properties();
3367
3368 // Make sure to initialize log configuration *before* parsing arguments
3369 LogConfiguration::initialize(create_vm_timer.begin_time());
3370
3371 // Parse arguments
3372 jint parse_result = Arguments::parse(args);
3373 if (parse_result != JNI_OK) return parse_result;
3374
3375 os::init_before_ergo();
3376
3377 jint ergo_result = Arguments::apply_ergo();
3378 if (ergo_result != JNI_OK) return ergo_result;
3379
3380 // Final check of all ranges after ergonomics which may change values.
3381 if (!CommandLineFlagRangeList::check_ranges()) {
3382 return JNI_EINVAL;
3383 }
3384
3385 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3386 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3387 if (!constraint_result) {
3388 return JNI_EINVAL;
3389 }
3390
3391 if (PauseAtStartup) {
3392 os::pause();
3393 }
3394
3395 HOTSPOT_VM_INIT_BEGIN();
3396
3397 // Timing (must come after argument parsing)
3398 TraceTime timer("Create VM", TraceStartupTime);
3399
3400 // Initialize the os module after parsing the args
3401 jint os_init_2_result = os::init_2();
3402 if (os_init_2_result != JNI_OK) return os_init_2_result;
3403
3404 jint adjust_after_os_result = Arguments::adjust_after_os();
3405 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3406
3407 // Initialize library-based TLS
3408 ThreadLocalStorage::init();
3409
3410 // Initialize output stream logging
3411 ostream_init_log();
3412
3413 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3414 // Must be before create_vm_init_agents()
3415 if (Arguments::init_libraries_at_startup()) {
3416 convert_vm_init_libraries_to_agents();
3417 }
3418
3419 // Launch -agentlib/-agentpath and converted -Xrun agents
3420 if (Arguments::init_agents_at_startup()) {
3421 create_vm_init_agents();
3422 }
3423
3424 // Initialize Threads state
3425 _thread_list = NULL;
3426 _number_of_threads = 0;
3427 _number_of_non_daemon_threads = 0;
3428
3429 // Initialize global data structures and create system classes in heap
3430 vm_init_globals();
3431
3432 #if INCLUDE_JVMCI
3433 if (JVMCICounterSize > 0) {
3434 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3435 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3436 } else {
3437 JavaThread::_jvmci_old_thread_counters = NULL;
3438 }
3439 #endif // INCLUDE_JVMCI
3440
3441 // Attach the main thread to this os thread
3442 JavaThread* main_thread = new JavaThread();
3443 main_thread->set_thread_state(_thread_in_vm);
3444 main_thread->initialize_thread_current();
3445 // must do this before set_active_handles
3446 main_thread->record_stack_base_and_size();
3447 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3448
3449 if (!main_thread->set_as_starting_thread()) {
3450 vm_shutdown_during_initialization(
3451 "Failed necessary internal allocation. Out of swap space");
3452 delete main_thread;
3453 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3454 return JNI_ENOMEM;
3455 }
3456
3457 // Enable guard page *after* os::create_main_thread(), otherwise it would
3458 // crash Linux VM, see notes in os_linux.cpp.
3459 main_thread->create_stack_guard_pages();
3460
3461 // Initialize Java-Level synchronization subsystem
3462 ObjectMonitor::Initialize();
3463
3464 // Initialize global modules
3465 jint status = init_globals();
3466 if (status != JNI_OK) {
3467 delete main_thread;
3468 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3469 return status;
3470 }
3471
3472 // Should be done after the heap is fully created
3473 main_thread->cache_global_variables();
3474
3475 HandleMark hm;
3476
3477 { MutexLocker mu(Threads_lock);
3478 Threads::add(main_thread);
3479 }
3480
3481 // Any JVMTI raw monitors entered in onload will transition into
3482 // real raw monitor. VM is setup enough here for raw monitor enter.
3483 JvmtiExport::transition_pending_onload_raw_monitors();
3484
3485 // Create the VMThread
3486 { TraceTime timer("Start VMThread", TraceStartupTime);
3487 VMThread::create();
3488 Thread* vmthread = VMThread::vm_thread();
3489
3490 if (!os::create_thread(vmthread, os::vm_thread)) {
3491 vm_exit_during_initialization("Cannot create VM thread. "
3492 "Out of system resources.");
3493 }
3494
3495 // Wait for the VM thread to become ready, and VMThread::run to initialize
3496 // Monitors can have spurious returns, must always check another state flag
3497 {
3498 MutexLocker ml(Notify_lock);
3499 os::start_thread(vmthread);
3500 while (vmthread->active_handles() == NULL) {
3501 Notify_lock->wait();
3502 }
3503 }
3504 }
3505
3506 assert(Universe::is_fully_initialized(), "not initialized");
3507 if (VerifyDuringStartup) {
3508 // Make sure we're starting with a clean slate.
3509 VM_Verify verify_op;
3510 VMThread::execute(&verify_op);
3511 }
3512
3513 Thread* THREAD = Thread::current();
3514
3515 // At this point, the Universe is initialized, but we have not executed
3516 // any byte code. Now is a good time (the only time) to dump out the
3517 // internal state of the JVM for sharing.
3518 if (DumpSharedSpaces) {
3519 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3520 ShouldNotReachHere();
3521 }
3522
3523 // Always call even when there are not JVMTI environments yet, since environments
3524 // may be attached late and JVMTI must track phases of VM execution
3525 JvmtiExport::enter_start_phase();
3526
3527 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3528 JvmtiExport::post_vm_start();
3529
3530 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3531
3532 // We need this for ClassDataSharing - the initial vm.info property is set
3533 // with the default value of CDS "sharing" which may be reset through
3534 // command line options.
3535 reset_vm_info_property(CHECK_JNI_ERR);
3536
3537 quicken_jni_functions();
3538
3539 // Must be run after init_ft which initializes ft_enabled
3540 if (TRACE_INITIALIZE() != JNI_OK) {
3541 vm_exit_during_initialization("Failed to initialize tracing backend");
3542 }
3543
3544 // Set flag that basic initialization has completed. Used by exceptions and various
3545 // debug stuff, that does not work until all basic classes have been initialized.
3546 set_init_completed();
3547
3548 LogConfiguration::post_initialize();
3549 Metaspace::post_initialize();
3550
3551 HOTSPOT_VM_INIT_END();
3552
3553 // record VM initialization completion time
3554 #if INCLUDE_MANAGEMENT
3555 Management::record_vm_init_completed();
3556 #endif // INCLUDE_MANAGEMENT
3557
3558 // Compute system loader. Note that this has to occur after set_init_completed, since
3559 // valid exceptions may be thrown in the process.
3560 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3561 // set_init_completed has just been called, causing exceptions not to be shortcut
3562 // anymore. We call vm_exit_during_initialization directly instead.
3563 SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR));
3564
3565 #if INCLUDE_ALL_GCS
3566 // Support for ConcurrentMarkSweep. This should be cleaned up
3567 // and better encapsulated. The ugly nested if test would go away
3568 // once things are properly refactored. XXX YSR
3569 if (UseConcMarkSweepGC || UseG1GC) {
3570 if (UseConcMarkSweepGC) {
3571 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3572 } else {
3573 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3574 }
3575 }
3576 #endif // INCLUDE_ALL_GCS
3577
3578 // Always call even when there are not JVMTI environments yet, since environments
3579 // may be attached late and JVMTI must track phases of VM execution
3580 JvmtiExport::enter_live_phase();
3581
3582 // Signal Dispatcher needs to be started before VMInit event is posted
3583 os::signal_init();
3584
3585 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3586 if (!DisableAttachMechanism) {
3587 AttachListener::vm_start();
3588 if (StartAttachListener || AttachListener::init_at_startup()) {
3589 AttachListener::init();
3590 }
3591 }
3592
3593 // Launch -Xrun agents
3594 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3595 // back-end can launch with -Xdebug -Xrunjdwp.
3596 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3597 create_vm_init_libraries();
3598 }
3599
3600 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3601 JvmtiExport::post_vm_initialized();
3602
3603 if (TRACE_START() != JNI_OK) {
3604 vm_exit_during_initialization("Failed to start tracing backend.");
3605 }
3606
3607 if (CleanChunkPoolAsync) {
3608 Chunk::start_chunk_pool_cleaner_task();
3609 }
3610
3611 #if INCLUDE_JVMCI
3612 if (EnableJVMCI) {
3613 const char* jvmciCompiler = Arguments::PropertyList_get_value(Arguments::system_properties(), "jvmci.compiler");
3614 if (jvmciCompiler != NULL) {
3615 JVMCIRuntime::save_compiler(jvmciCompiler);
3616 }
3617 }
3618 #endif // INCLUDE_JVMCI
3619
3620 // initialize compiler(s)
3621 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI
3622 CompileBroker::compilation_init();
3623 #endif
3624
3625 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3626 // It is done after compilers are initialized, because otherwise compilations of
3627 // signature polymorphic MH intrinsics can be missed
3628 // (see SystemDictionary::find_method_handle_intrinsic).
3629 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3630
3631 #if INCLUDE_MANAGEMENT
3632 Management::initialize(THREAD);
3633
3634 if (HAS_PENDING_EXCEPTION) {
3635 // management agent fails to start possibly due to
3636 // configuration problem and is responsible for printing
3637 // stack trace if appropriate. Simply exit VM.
3638 vm_exit(1);
3639 }
3640 #endif // INCLUDE_MANAGEMENT
3641
3642 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3643 if (MemProfiling) MemProfiler::engage();
3644 StatSampler::engage();
3645 if (CheckJNICalls) JniPeriodicChecker::engage();
3646
3647 BiasedLocking::init();
3648
3649 #if INCLUDE_RTM_OPT
3650 RTMLockingCounters::init();
3651 #endif
3652
3653 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3654 call_postVMInitHook(THREAD);
3655 // The Java side of PostVMInitHook.run must deal with all
3656 // exceptions and provide means of diagnosis.
3657 if (HAS_PENDING_EXCEPTION) {
3658 CLEAR_PENDING_EXCEPTION;
3659 }
3660 }
3661
3662 {
3663 MutexLocker ml(PeriodicTask_lock);
3664 // Make sure the WatcherThread can be started by WatcherThread::start()
3665 // or by dynamic enrollment.
3666 WatcherThread::make_startable();
3667 // Start up the WatcherThread if there are any periodic tasks
3668 // NOTE: All PeriodicTasks should be registered by now. If they
3669 // aren't, late joiners might appear to start slowly (we might
3670 // take a while to process their first tick).
3671 if (PeriodicTask::num_tasks() > 0) {
3672 WatcherThread::start();
3673 }
3674 }
3675
3676 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3677
3678 create_vm_timer.end();
3679 #ifdef ASSERT
3680 _vm_complete = true;
3681 #endif
3682 return JNI_OK;
3683 }
3684
3685 // type for the Agent_OnLoad and JVM_OnLoad entry points
3686 extern "C" {
3687 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3688 }
3689 // Find a command line agent library and return its entry point for
3690 // -agentlib: -agentpath: -Xrun
3691 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3692 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3693 const char *on_load_symbols[],
3694 size_t num_symbol_entries) {
3695 OnLoadEntry_t on_load_entry = NULL;
3696 void *library = NULL;
3697
3698 if (!agent->valid()) {
3699 char buffer[JVM_MAXPATHLEN];
3700 char ebuf[1024] = "";
3701 const char *name = agent->name();
3702 const char *msg = "Could not find agent library ";
3703
3704 // First check to see if agent is statically linked into executable
3705 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3706 library = agent->os_lib();
3707 } else if (agent->is_absolute_path()) {
3708 library = os::dll_load(name, ebuf, sizeof ebuf);
3709 if (library == NULL) {
3710 const char *sub_msg = " in absolute path, with error: ";
3711 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3712 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3713 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3714 // If we can't find the agent, exit.
3715 vm_exit_during_initialization(buf, NULL);
3716 FREE_C_HEAP_ARRAY(char, buf);
3717 }
3718 } else {
3719 // Try to load the agent from the standard dll directory
3720 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3721 name)) {
3722 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3723 }
3724 if (library == NULL) { // Try the local directory
3725 char ns[1] = {0};
3726 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3727 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3728 }
3729 if (library == NULL) {
3730 const char *sub_msg = " on the library path, with error: ";
3731 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3732 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3733 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3734 // If we can't find the agent, exit.
3735 vm_exit_during_initialization(buf, NULL);
3736 FREE_C_HEAP_ARRAY(char, buf);
3737 }
3738 }
3739 }
3740 agent->set_os_lib(library);
3741 agent->set_valid();
3742 }
3743
3744 // Find the OnLoad function.
3745 on_load_entry =
3746 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3747 false,
3748 on_load_symbols,
3749 num_symbol_entries));
3750 return on_load_entry;
3751 }
3752
3753 // Find the JVM_OnLoad entry point
3754 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3755 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3756 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3757 }
3758
3759 // Find the Agent_OnLoad entry point
3760 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3761 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3762 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3763 }
3764
3765 // For backwards compatibility with -Xrun
3766 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3767 // treated like -agentpath:
3768 // Must be called before agent libraries are created
3769 void Threads::convert_vm_init_libraries_to_agents() {
3770 AgentLibrary* agent;
3771 AgentLibrary* next;
3772
3773 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3774 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3775 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3776
3777 // If there is an JVM_OnLoad function it will get called later,
3778 // otherwise see if there is an Agent_OnLoad
3779 if (on_load_entry == NULL) {
3780 on_load_entry = lookup_agent_on_load(agent);
3781 if (on_load_entry != NULL) {
3782 // switch it to the agent list -- so that Agent_OnLoad will be called,
3783 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3784 Arguments::convert_library_to_agent(agent);
3785 } else {
3786 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3787 }
3788 }
3789 }
3790 }
3791
3792 // Create agents for -agentlib: -agentpath: and converted -Xrun
3793 // Invokes Agent_OnLoad
3794 // Called very early -- before JavaThreads exist
3795 void Threads::create_vm_init_agents() {
3796 extern struct JavaVM_ main_vm;
3797 AgentLibrary* agent;
3798
3799 JvmtiExport::enter_onload_phase();
3800
3801 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3802 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3803
3804 if (on_load_entry != NULL) {
3805 // Invoke the Agent_OnLoad function
3806 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3807 if (err != JNI_OK) {
3808 vm_exit_during_initialization("agent library failed to init", agent->name());
3809 }
3810 } else {
3811 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3812 }
3813 }
3814 JvmtiExport::enter_primordial_phase();
3815 }
3816
3817 extern "C" {
3818 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3819 }
3820
3821 void Threads::shutdown_vm_agents() {
3822 // Send any Agent_OnUnload notifications
3823 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3824 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3825 extern struct JavaVM_ main_vm;
3826 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3827
3828 // Find the Agent_OnUnload function.
3829 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3830 os::find_agent_function(agent,
3831 false,
3832 on_unload_symbols,
3833 num_symbol_entries));
3834
3835 // Invoke the Agent_OnUnload function
3836 if (unload_entry != NULL) {
3837 JavaThread* thread = JavaThread::current();
3838 ThreadToNativeFromVM ttn(thread);
3839 HandleMark hm(thread);
3840 (*unload_entry)(&main_vm);
3841 }
3842 }
3843 }
3844
3845 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3846 // Invokes JVM_OnLoad
3847 void Threads::create_vm_init_libraries() {
3848 extern struct JavaVM_ main_vm;
3849 AgentLibrary* agent;
3850
3851 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3852 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3853
3854 if (on_load_entry != NULL) {
3855 // Invoke the JVM_OnLoad function
3856 JavaThread* thread = JavaThread::current();
3857 ThreadToNativeFromVM ttn(thread);
3858 HandleMark hm(thread);
3859 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3860 if (err != JNI_OK) {
3861 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3862 }
3863 } else {
3864 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3865 }
3866 }
3867 }
3868
3869 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3870 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3871
3872 JavaThread* java_thread = NULL;
3873 // Sequential search for now. Need to do better optimization later.
3874 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3875 oop tobj = thread->threadObj();
3876 if (!thread->is_exiting() &&
3877 tobj != NULL &&
3878 java_tid == java_lang_Thread::thread_id(tobj)) {
3879 java_thread = thread;
3880 break;
3881 }
3882 }
3883 return java_thread;
3884 }
3885
3886
3887 // Last thread running calls java.lang.Shutdown.shutdown()
3888 void JavaThread::invoke_shutdown_hooks() {
3889 HandleMark hm(this);
3890
3891 // We could get here with a pending exception, if so clear it now.
3892 if (this->has_pending_exception()) {
3893 this->clear_pending_exception();
3894 }
3895
3896 EXCEPTION_MARK;
3897 Klass* k =
3898 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3899 THREAD);
3900 if (k != NULL) {
3901 // SystemDictionary::resolve_or_null will return null if there was
3902 // an exception. If we cannot load the Shutdown class, just don't
3903 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3904 // and finalizers (if runFinalizersOnExit is set) won't be run.
3905 // Note that if a shutdown hook was registered or runFinalizersOnExit
3906 // was called, the Shutdown class would have already been loaded
3907 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3908 instanceKlassHandle shutdown_klass (THREAD, k);
3909 JavaValue result(T_VOID);
3910 JavaCalls::call_static(&result,
3911 shutdown_klass,
3912 vmSymbols::shutdown_method_name(),
3913 vmSymbols::void_method_signature(),
3914 THREAD);
3915 }
3916 CLEAR_PENDING_EXCEPTION;
3917 }
3918
3919 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3920 // the program falls off the end of main(). Another VM exit path is through
3921 // vm_exit() when the program calls System.exit() to return a value or when
3922 // there is a serious error in VM. The two shutdown paths are not exactly
3923 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3924 // and VM_Exit op at VM level.
3925 //
3926 // Shutdown sequence:
3927 // + Shutdown native memory tracking if it is on
3928 // + Wait until we are the last non-daemon thread to execute
3929 // <-- every thing is still working at this moment -->
3930 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3931 // shutdown hooks, run finalizers if finalization-on-exit
3932 // + Call before_exit(), prepare for VM exit
3933 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3934 // currently the only user of this mechanism is File.deleteOnExit())
3935 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3936 // post thread end and vm death events to JVMTI,
3937 // stop signal thread
3938 // + Call JavaThread::exit(), it will:
3939 // > release JNI handle blocks, remove stack guard pages
3940 // > remove this thread from Threads list
3941 // <-- no more Java code from this thread after this point -->
3942 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3943 // the compiler threads at safepoint
3944 // <-- do not use anything that could get blocked by Safepoint -->
3945 // + Disable tracing at JNI/JVM barriers
3946 // + Set _vm_exited flag for threads that are still running native code
3947 // + Delete this thread
3948 // + Call exit_globals()
3949 // > deletes tty
3950 // > deletes PerfMemory resources
3951 // + Return to caller
3952
3953 bool Threads::destroy_vm() {
3954 JavaThread* thread = JavaThread::current();
3955
3956 #ifdef ASSERT
3957 _vm_complete = false;
3958 #endif
3959 // Wait until we are the last non-daemon thread to execute
3960 { MutexLocker nu(Threads_lock);
3961 while (Threads::number_of_non_daemon_threads() > 1)
3962 // This wait should make safepoint checks, wait without a timeout,
3963 // and wait as a suspend-equivalent condition.
3964 //
3965 // Note: If the FlatProfiler is running and this thread is waiting
3966 // for another non-daemon thread to finish, then the FlatProfiler
3967 // is waiting for the external suspend request on this thread to
3968 // complete. wait_for_ext_suspend_completion() will eventually
3969 // timeout, but that takes time. Making this wait a suspend-
3970 // equivalent condition solves that timeout problem.
3971 //
3972 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3973 Mutex::_as_suspend_equivalent_flag);
3974 }
3975
3976 // Hang forever on exit if we are reporting an error.
3977 if (ShowMessageBoxOnError && is_error_reported()) {
3978 os::infinite_sleep();
3979 }
3980 os::wait_for_keypress_at_exit();
3981
3982 // run Java level shutdown hooks
3983 thread->invoke_shutdown_hooks();
3984
3985 before_exit(thread);
3986
3987 thread->exit(true);
3988
3989 // Stop VM thread.
3990 {
3991 // 4945125 The vm thread comes to a safepoint during exit.
3992 // GC vm_operations can get caught at the safepoint, and the
3993 // heap is unparseable if they are caught. Grab the Heap_lock
3994 // to prevent this. The GC vm_operations will not be able to
3995 // queue until after the vm thread is dead. After this point,
3996 // we'll never emerge out of the safepoint before the VM exits.
3997
3998 MutexLocker ml(Heap_lock);
3999
4000 VMThread::wait_for_vm_thread_exit();
4001 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4002 VMThread::destroy();
4003 }
4004
4005 // clean up ideal graph printers
4006 #if defined(COMPILER2) && !defined(PRODUCT)
4007 IdealGraphPrinter::clean_up();
4008 #endif
4009
4010 // Now, all Java threads are gone except daemon threads. Daemon threads
4011 // running Java code or in VM are stopped by the Safepoint. However,
4012 // daemon threads executing native code are still running. But they
4013 // will be stopped at native=>Java/VM barriers. Note that we can't
4014 // simply kill or suspend them, as it is inherently deadlock-prone.
4015
4016 #ifndef PRODUCT
4017 // disable function tracing at JNI/JVM barriers
4018 TraceJNICalls = false;
4019 TraceJVMCalls = false;
4020 TraceRuntimeCalls = false;
4021 #endif
4022
4023 VM_Exit::set_vm_exited();
4024
4025 notify_vm_shutdown();
4026
4027 delete thread;
4028
4029 #if INCLUDE_JVMCI
4030 if (JVMCICounterSize > 0) {
4031 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4032 }
4033 #endif
4034
4035 // exit_globals() will delete tty
4036 exit_globals();
4037
4038 LogConfiguration::finalize();
4039
4040 return true;
4041 }
4042
4043
4044 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4045 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4046 return is_supported_jni_version(version);
4047 }
4048
4049
4050 jboolean Threads::is_supported_jni_version(jint version) {
4051 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4052 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4053 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4054 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4055 return JNI_FALSE;
4056 }
4057
4058
4059 void Threads::add(JavaThread* p, bool force_daemon) {
4060 // The threads lock must be owned at this point
4061 assert_locked_or_safepoint(Threads_lock);
4062
4063 // See the comment for this method in thread.hpp for its purpose and
4064 // why it is called here.
4065 p->initialize_queues();
4066 p->set_next(_thread_list);
4067 _thread_list = p;
4068 _number_of_threads++;
4069 oop threadObj = p->threadObj();
4070 bool daemon = true;
4071 // Bootstrapping problem: threadObj can be null for initial
4072 // JavaThread (or for threads attached via JNI)
4073 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4074 _number_of_non_daemon_threads++;
4075 daemon = false;
4076 }
4077
4078 ThreadService::add_thread(p, daemon);
4079
4080 // Possible GC point.
4081 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4082 }
4083
4084 void Threads::remove(JavaThread* p) {
4085 // Extra scope needed for Thread_lock, so we can check
4086 // that we do not remove thread without safepoint code notice
4087 { MutexLocker ml(Threads_lock);
4088
4089 assert(includes(p), "p must be present");
4090
4091 JavaThread* current = _thread_list;
4092 JavaThread* prev = NULL;
4093
4094 while (current != p) {
4095 prev = current;
4096 current = current->next();
4097 }
4098
4099 if (prev) {
4100 prev->set_next(current->next());
4101 } else {
4102 _thread_list = p->next();
4103 }
4104 _number_of_threads--;
4105 oop threadObj = p->threadObj();
4106 bool daemon = true;
4107 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4108 _number_of_non_daemon_threads--;
4109 daemon = false;
4110
4111 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4112 // on destroy_vm will wake up.
4113 if (number_of_non_daemon_threads() == 1) {
4114 Threads_lock->notify_all();
4115 }
4116 }
4117 ThreadService::remove_thread(p, daemon);
4118
4119 // Make sure that safepoint code disregard this thread. This is needed since
4120 // the thread might mess around with locks after this point. This can cause it
4121 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4122 // of this thread since it is removed from the queue.
4123 p->set_terminated_value();
4124 } // unlock Threads_lock
4125
4126 // Since Events::log uses a lock, we grab it outside the Threads_lock
4127 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4128 }
4129
4130 // Threads_lock must be held when this is called (or must be called during a safepoint)
4131 bool Threads::includes(JavaThread* p) {
4132 assert(Threads_lock->is_locked(), "sanity check");
4133 ALL_JAVA_THREADS(q) {
4134 if (q == p) {
4135 return true;
4136 }
4137 }
4138 return false;
4139 }
4140
4141 // Operations on the Threads list for GC. These are not explicitly locked,
4142 // but the garbage collector must provide a safe context for them to run.
4143 // In particular, these things should never be called when the Threads_lock
4144 // is held by some other thread. (Note: the Safepoint abstraction also
4145 // uses the Threads_lock to guarantee this property. It also makes sure that
4146 // all threads gets blocked when exiting or starting).
4147
4148 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4149 ALL_JAVA_THREADS(p) {
4150 p->oops_do(f, cld_f, cf);
4151 }
4152 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4153 }
4154
4155 void Threads::change_thread_claim_parity() {
4156 // Set the new claim parity.
4157 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4158 "Not in range.");
4159 _thread_claim_parity++;
4160 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4161 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4162 "Not in range.");
4163 }
4164
4165 #ifdef ASSERT
4166 void Threads::assert_all_threads_claimed() {
4167 ALL_JAVA_THREADS(p) {
4168 const int thread_parity = p->oops_do_parity();
4169 assert((thread_parity == _thread_claim_parity),
4170 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4171 }
4172 }
4173 #endif // ASSERT
4174
4175 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4176 int cp = Threads::thread_claim_parity();
4177 ALL_JAVA_THREADS(p) {
4178 if (p->claim_oops_do(is_par, cp)) {
4179 p->oops_do(f, cld_f, cf);
4180 }
4181 }
4182 VMThread* vmt = VMThread::vm_thread();
4183 if (vmt->claim_oops_do(is_par, cp)) {
4184 vmt->oops_do(f, cld_f, cf);
4185 }
4186 }
4187
4188 #if INCLUDE_ALL_GCS
4189 // Used by ParallelScavenge
4190 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4191 ALL_JAVA_THREADS(p) {
4192 q->enqueue(new ThreadRootsTask(p));
4193 }
4194 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4195 }
4196
4197 // Used by Parallel Old
4198 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4199 ALL_JAVA_THREADS(p) {
4200 q->enqueue(new ThreadRootsMarkingTask(p));
4201 }
4202 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4203 }
4204 #endif // INCLUDE_ALL_GCS
4205
4206 void Threads::nmethods_do(CodeBlobClosure* cf) {
4207 ALL_JAVA_THREADS(p) {
4208 p->nmethods_do(cf);
4209 }
4210 VMThread::vm_thread()->nmethods_do(cf);
4211 }
4212
4213 void Threads::metadata_do(void f(Metadata*)) {
4214 ALL_JAVA_THREADS(p) {
4215 p->metadata_do(f);
4216 }
4217 }
4218
4219 class ThreadHandlesClosure : public ThreadClosure {
4220 void (*_f)(Metadata*);
4221 public:
4222 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4223 virtual void do_thread(Thread* thread) {
4224 thread->metadata_handles_do(_f);
4225 }
4226 };
4227
4228 void Threads::metadata_handles_do(void f(Metadata*)) {
4229 // Only walk the Handles in Thread.
4230 ThreadHandlesClosure handles_closure(f);
4231 threads_do(&handles_closure);
4232 }
4233
4234 void Threads::deoptimized_wrt_marked_nmethods() {
4235 ALL_JAVA_THREADS(p) {
4236 p->deoptimized_wrt_marked_nmethods();
4237 }
4238 }
4239
4240
4241 // Get count Java threads that are waiting to enter the specified monitor.
4242 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4243 address monitor,
4244 bool doLock) {
4245 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4246 "must grab Threads_lock or be at safepoint");
4247 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4248
4249 int i = 0;
4250 {
4251 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4252 ALL_JAVA_THREADS(p) {
4253 if (!p->can_call_java()) continue;
4254
4255 address pending = (address)p->current_pending_monitor();
4256 if (pending == monitor) { // found a match
4257 if (i < count) result->append(p); // save the first count matches
4258 i++;
4259 }
4260 }
4261 }
4262 return result;
4263 }
4264
4265
4266 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4267 bool doLock) {
4268 assert(doLock ||
4269 Threads_lock->owned_by_self() ||
4270 SafepointSynchronize::is_at_safepoint(),
4271 "must grab Threads_lock or be at safepoint");
4272
4273 // NULL owner means not locked so we can skip the search
4274 if (owner == NULL) return NULL;
4275
4276 {
4277 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4278 ALL_JAVA_THREADS(p) {
4279 // first, see if owner is the address of a Java thread
4280 if (owner == (address)p) return p;
4281 }
4282 }
4283 // Cannot assert on lack of success here since this function may be
4284 // used by code that is trying to report useful problem information
4285 // like deadlock detection.
4286 if (UseHeavyMonitors) return NULL;
4287
4288 // If we didn't find a matching Java thread and we didn't force use of
4289 // heavyweight monitors, then the owner is the stack address of the
4290 // Lock Word in the owning Java thread's stack.
4291 //
4292 JavaThread* the_owner = NULL;
4293 {
4294 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4295 ALL_JAVA_THREADS(q) {
4296 if (q->is_lock_owned(owner)) {
4297 the_owner = q;
4298 break;
4299 }
4300 }
4301 }
4302 // cannot assert on lack of success here; see above comment
4303 return the_owner;
4304 }
4305
4306 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4307 void Threads::print_on(outputStream* st, bool print_stacks,
4308 bool internal_format, bool print_concurrent_locks) {
4309 char buf[32];
4310 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4311
4312 st->print_cr("Full thread dump %s (%s %s):",
4313 Abstract_VM_Version::vm_name(),
4314 Abstract_VM_Version::vm_release(),
4315 Abstract_VM_Version::vm_info_string());
4316 st->cr();
4317
4318 #if INCLUDE_SERVICES
4319 // Dump concurrent locks
4320 ConcurrentLocksDump concurrent_locks;
4321 if (print_concurrent_locks) {
4322 concurrent_locks.dump_at_safepoint();
4323 }
4324 #endif // INCLUDE_SERVICES
4325
4326 ALL_JAVA_THREADS(p) {
4327 ResourceMark rm;
4328 p->print_on(st);
4329 if (print_stacks) {
4330 if (internal_format) {
4331 p->trace_stack();
4332 } else {
4333 p->print_stack_on(st);
4334 }
4335 }
4336 st->cr();
4337 #if INCLUDE_SERVICES
4338 if (print_concurrent_locks) {
4339 concurrent_locks.print_locks_on(p, st);
4340 }
4341 #endif // INCLUDE_SERVICES
4342 }
4343
4344 VMThread::vm_thread()->print_on(st);
4345 st->cr();
4346 Universe::heap()->print_gc_threads_on(st);
4347 WatcherThread* wt = WatcherThread::watcher_thread();
4348 if (wt != NULL) {
4349 wt->print_on(st);
4350 st->cr();
4351 }
4352 CompileBroker::print_compiler_threads_on(st);
4353 st->flush();
4354 }
4355
4356 // Threads::print_on_error() is called by fatal error handler. It's possible
4357 // that VM is not at safepoint and/or current thread is inside signal handler.
4358 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4359 // memory (even in resource area), it might deadlock the error handler.
4360 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4361 int buflen) {
4362 bool found_current = false;
4363 st->print_cr("Java Threads: ( => current thread )");
4364 ALL_JAVA_THREADS(thread) {
4365 bool is_current = (current == thread);
4366 found_current = found_current || is_current;
4367
4368 st->print("%s", is_current ? "=>" : " ");
4369
4370 st->print(PTR_FORMAT, p2i(thread));
4371 st->print(" ");
4372 thread->print_on_error(st, buf, buflen);
4373 st->cr();
4374 }
4375 st->cr();
4376
4377 st->print_cr("Other Threads:");
4378 if (VMThread::vm_thread()) {
4379 bool is_current = (current == VMThread::vm_thread());
4380 found_current = found_current || is_current;
4381 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4382
4383 st->print(PTR_FORMAT, p2i(VMThread::vm_thread()));
4384 st->print(" ");
4385 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4386 st->cr();
4387 }
4388 WatcherThread* wt = WatcherThread::watcher_thread();
4389 if (wt != NULL) {
4390 bool is_current = (current == wt);
4391 found_current = found_current || is_current;
4392 st->print("%s", is_current ? "=>" : " ");
4393
4394 st->print(PTR_FORMAT, p2i(wt));
4395 st->print(" ");
4396 wt->print_on_error(st, buf, buflen);
4397 st->cr();
4398 }
4399 if (!found_current) {
4400 st->cr();
4401 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4402 current->print_on_error(st, buf, buflen);
4403 st->cr();
4404 }
4405 }
4406
4407 // Internal SpinLock and Mutex
4408 // Based on ParkEvent
4409
4410 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4411 //
4412 // We employ SpinLocks _only for low-contention, fixed-length
4413 // short-duration critical sections where we're concerned
4414 // about native mutex_t or HotSpot Mutex:: latency.
4415 // The mux construct provides a spin-then-block mutual exclusion
4416 // mechanism.
4417 //
4418 // Testing has shown that contention on the ListLock guarding gFreeList
4419 // is common. If we implement ListLock as a simple SpinLock it's common
4420 // for the JVM to devolve to yielding with little progress. This is true
4421 // despite the fact that the critical sections protected by ListLock are
4422 // extremely short.
4423 //
4424 // TODO-FIXME: ListLock should be of type SpinLock.
4425 // We should make this a 1st-class type, integrated into the lock
4426 // hierarchy as leaf-locks. Critically, the SpinLock structure
4427 // should have sufficient padding to avoid false-sharing and excessive
4428 // cache-coherency traffic.
4429
4430
4431 typedef volatile int SpinLockT;
4432
4433 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4434 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4435 return; // normal fast-path return
4436 }
4437
4438 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4439 TEVENT(SpinAcquire - ctx);
4440 int ctr = 0;
4441 int Yields = 0;
4442 for (;;) {
4443 while (*adr != 0) {
4444 ++ctr;
4445 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4446 if (Yields > 5) {
4447 os::naked_short_sleep(1);
4448 } else {
4449 os::naked_yield();
4450 ++Yields;
4451 }
4452 } else {
4453 SpinPause();
4454 }
4455 }
4456 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4457 }
4458 }
4459
4460 void Thread::SpinRelease(volatile int * adr) {
4461 assert(*adr != 0, "invariant");
4462 OrderAccess::fence(); // guarantee at least release consistency.
4463 // Roach-motel semantics.
4464 // It's safe if subsequent LDs and STs float "up" into the critical section,
4465 // but prior LDs and STs within the critical section can't be allowed
4466 // to reorder or float past the ST that releases the lock.
4467 // Loads and stores in the critical section - which appear in program
4468 // order before the store that releases the lock - must also appear
4469 // before the store that releases the lock in memory visibility order.
4470 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4471 // the ST of 0 into the lock-word which releases the lock, so fence
4472 // more than covers this on all platforms.
4473 *adr = 0;
4474 }
4475
4476 // muxAcquire and muxRelease:
4477 //
4478 // * muxAcquire and muxRelease support a single-word lock-word construct.
4479 // The LSB of the word is set IFF the lock is held.
4480 // The remainder of the word points to the head of a singly-linked list
4481 // of threads blocked on the lock.
4482 //
4483 // * The current implementation of muxAcquire-muxRelease uses its own
4484 // dedicated Thread._MuxEvent instance. If we're interested in
4485 // minimizing the peak number of extant ParkEvent instances then
4486 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4487 // as certain invariants were satisfied. Specifically, care would need
4488 // to be taken with regards to consuming unpark() "permits".
4489 // A safe rule of thumb is that a thread would never call muxAcquire()
4490 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4491 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4492 // consume an unpark() permit intended for monitorenter, for instance.
4493 // One way around this would be to widen the restricted-range semaphore
4494 // implemented in park(). Another alternative would be to provide
4495 // multiple instances of the PlatformEvent() for each thread. One
4496 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4497 //
4498 // * Usage:
4499 // -- Only as leaf locks
4500 // -- for short-term locking only as muxAcquire does not perform
4501 // thread state transitions.
4502 //
4503 // Alternatives:
4504 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4505 // but with parking or spin-then-park instead of pure spinning.
4506 // * Use Taura-Oyama-Yonenzawa locks.
4507 // * It's possible to construct a 1-0 lock if we encode the lockword as
4508 // (List,LockByte). Acquire will CAS the full lockword while Release
4509 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4510 // acquiring threads use timers (ParkTimed) to detect and recover from
4511 // the stranding window. Thread/Node structures must be aligned on 256-byte
4512 // boundaries by using placement-new.
4513 // * Augment MCS with advisory back-link fields maintained with CAS().
4514 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4515 // The validity of the backlinks must be ratified before we trust the value.
4516 // If the backlinks are invalid the exiting thread must back-track through the
4517 // the forward links, which are always trustworthy.
4518 // * Add a successor indication. The LockWord is currently encoded as
4519 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4520 // to provide the usual futile-wakeup optimization.
4521 // See RTStt for details.
4522 // * Consider schedctl.sc_nopreempt to cover the critical section.
4523 //
4524
4525
4526 typedef volatile intptr_t MutexT; // Mux Lock-word
4527 enum MuxBits { LOCKBIT = 1 };
4528
4529 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4530 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4531 if (w == 0) return;
4532 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4533 return;
4534 }
4535
4536 TEVENT(muxAcquire - Contention);
4537 ParkEvent * const Self = Thread::current()->_MuxEvent;
4538 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4539 for (;;) {
4540 int its = (os::is_MP() ? 100 : 0) + 1;
4541
4542 // Optional spin phase: spin-then-park strategy
4543 while (--its >= 0) {
4544 w = *Lock;
4545 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4546 return;
4547 }
4548 }
4549
4550 Self->reset();
4551 Self->OnList = intptr_t(Lock);
4552 // The following fence() isn't _strictly necessary as the subsequent
4553 // CAS() both serializes execution and ratifies the fetched *Lock value.
4554 OrderAccess::fence();
4555 for (;;) {
4556 w = *Lock;
4557 if ((w & LOCKBIT) == 0) {
4558 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4559 Self->OnList = 0; // hygiene - allows stronger asserts
4560 return;
4561 }
4562 continue; // Interference -- *Lock changed -- Just retry
4563 }
4564 assert(w & LOCKBIT, "invariant");
4565 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4566 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4567 }
4568
4569 while (Self->OnList != 0) {
4570 Self->park();
4571 }
4572 }
4573 }
4574
4575 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4576 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4577 if (w == 0) return;
4578 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4579 return;
4580 }
4581
4582 TEVENT(muxAcquire - Contention);
4583 ParkEvent * ReleaseAfter = NULL;
4584 if (ev == NULL) {
4585 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4586 }
4587 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4588 for (;;) {
4589 guarantee(ev->OnList == 0, "invariant");
4590 int its = (os::is_MP() ? 100 : 0) + 1;
4591
4592 // Optional spin phase: spin-then-park strategy
4593 while (--its >= 0) {
4594 w = *Lock;
4595 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4596 if (ReleaseAfter != NULL) {
4597 ParkEvent::Release(ReleaseAfter);
4598 }
4599 return;
4600 }
4601 }
4602
4603 ev->reset();
4604 ev->OnList = intptr_t(Lock);
4605 // The following fence() isn't _strictly necessary as the subsequent
4606 // CAS() both serializes execution and ratifies the fetched *Lock value.
4607 OrderAccess::fence();
4608 for (;;) {
4609 w = *Lock;
4610 if ((w & LOCKBIT) == 0) {
4611 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4612 ev->OnList = 0;
4613 // We call ::Release while holding the outer lock, thus
4614 // artificially lengthening the critical section.
4615 // Consider deferring the ::Release() until the subsequent unlock(),
4616 // after we've dropped the outer lock.
4617 if (ReleaseAfter != NULL) {
4618 ParkEvent::Release(ReleaseAfter);
4619 }
4620 return;
4621 }
4622 continue; // Interference -- *Lock changed -- Just retry
4623 }
4624 assert(w & LOCKBIT, "invariant");
4625 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4626 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4627 }
4628
4629 while (ev->OnList != 0) {
4630 ev->park();
4631 }
4632 }
4633 }
4634
4635 // Release() must extract a successor from the list and then wake that thread.
4636 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4637 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4638 // Release() would :
4639 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4640 // (B) Extract a successor from the private list "in-hand"
4641 // (C) attempt to CAS() the residual back into *Lock over null.
4642 // If there were any newly arrived threads and the CAS() would fail.
4643 // In that case Release() would detach the RATs, re-merge the list in-hand
4644 // with the RATs and repeat as needed. Alternately, Release() might
4645 // detach and extract a successor, but then pass the residual list to the wakee.
4646 // The wakee would be responsible for reattaching and remerging before it
4647 // competed for the lock.
4648 //
4649 // Both "pop" and DMR are immune from ABA corruption -- there can be
4650 // multiple concurrent pushers, but only one popper or detacher.
4651 // This implementation pops from the head of the list. This is unfair,
4652 // but tends to provide excellent throughput as hot threads remain hot.
4653 // (We wake recently run threads first).
4654 //
4655 // All paths through muxRelease() will execute a CAS.
4656 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4657 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4658 // executed within the critical section are complete and globally visible before the
4659 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4660 void Thread::muxRelease(volatile intptr_t * Lock) {
4661 for (;;) {
4662 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4663 assert(w & LOCKBIT, "invariant");
4664 if (w == LOCKBIT) return;
4665 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4666 assert(List != NULL, "invariant");
4667 assert(List->OnList == intptr_t(Lock), "invariant");
4668 ParkEvent * const nxt = List->ListNext;
4669 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4670
4671 // The following CAS() releases the lock and pops the head element.
4672 // The CAS() also ratifies the previously fetched lock-word value.
4673 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4674 continue;
4675 }
4676 List->OnList = 0;
4677 OrderAccess::fence();
4678 List->unpark();
4679 return;
4680 }
4681 }
4682
4683
4684 void Threads::verify() {
4685 ALL_JAVA_THREADS(p) {
4686 p->verify();
4687 }
4688 VMThread* thread = VMThread::vm_thread();
4689 if (thread != NULL) thread->verify();
4690 }