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 // Current thread is maintained as a thread-local variable
145 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
146
147 // Class hierarchy
148 // - Thread
149 // - VMThread
150 // - WatcherThread
151 // - ConcurrentMarkSweepThread
152 // - JavaThread
153 // - CompilerThread
154
155 // ======= Thread ========
156 // Support for forcing alignment of thread objects for biased locking
157 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
158 if (UseBiasedLocking) {
159 const int alignment = markOopDesc::biased_lock_alignment;
160 size_t aligned_size = size + (alignment - sizeof(intptr_t));
161 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
162 : AllocateHeap(aligned_size, flags, CURRENT_PC,
163 AllocFailStrategy::RETURN_NULL);
164 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
165 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
166 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
167 "JavaThread alignment code overflowed allocated storage");
168 if (TraceBiasedLocking) {
169 if (aligned_addr != real_malloc_addr) {
170 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
171 p2i(real_malloc_addr), p2i(aligned_addr));
172 }
173 }
174 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
175 return aligned_addr;
176 } else {
177 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
178 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
179 }
180 }
181
182 void Thread::operator delete(void* p) {
183 if (UseBiasedLocking) {
184 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
185 FreeHeap(real_malloc_addr);
186 } else {
187 FreeHeap(p);
188 }
189 }
190
191
192 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
193 // JavaThread
194
195
196 Thread::Thread() {
197 // stack and get_thread
198 set_stack_base(NULL);
199 set_stack_size(0);
200 set_self_raw_id(0);
201 set_lgrp_id(-1);
202 DEBUG_ONLY(clear_suspendible_thread();)
203
204 // allocated data structures
205 set_osthread(NULL);
206 set_resource_area(new (mtThread)ResourceArea());
207 DEBUG_ONLY(_current_resource_mark = NULL;)
208 set_handle_area(new (mtThread) HandleArea(NULL));
209 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
210 set_active_handles(NULL);
211 set_free_handle_block(NULL);
212 set_last_handle_mark(NULL);
213
214 // This initial value ==> never claimed.
215 _oops_do_parity = 0;
216
217 // the handle mark links itself to last_handle_mark
218 new HandleMark(this);
219
220 // plain initialization
221 debug_only(_owned_locks = NULL;)
222 debug_only(_allow_allocation_count = 0;)
223 NOT_PRODUCT(_allow_safepoint_count = 0;)
224 NOT_PRODUCT(_skip_gcalot = false;)
225 _jvmti_env_iteration_count = 0;
226 set_allocated_bytes(0);
227 _vm_operation_started_count = 0;
228 _vm_operation_completed_count = 0;
229 _current_pending_monitor = NULL;
230 _current_pending_monitor_is_from_java = true;
231 _current_waiting_monitor = NULL;
232 _num_nested_signal = 0;
233 omFreeList = NULL;
234 omFreeCount = 0;
235 omFreeProvision = 32;
236 omInUseList = NULL;
237 omInUseCount = 0;
238
239 #ifdef ASSERT
240 _visited_for_critical_count = false;
241 #endif
242
243 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
244 Monitor::_safepoint_check_sometimes);
245 _suspend_flags = 0;
246
247 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
248 _hashStateX = os::random();
249 _hashStateY = 842502087;
250 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
251 _hashStateW = 273326509;
252
253 _OnTrap = 0;
254 _schedctl = NULL;
255 _Stalled = 0;
256 _TypeTag = 0x2BAD;
257
258 // Many of the following fields are effectively final - immutable
259 // Note that nascent threads can't use the Native Monitor-Mutex
260 // construct until the _MutexEvent is initialized ...
261 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
262 // we might instead use a stack of ParkEvents that we could provision on-demand.
263 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
264 // and ::Release()
265 _ParkEvent = ParkEvent::Allocate(this);
266 _SleepEvent = ParkEvent::Allocate(this);
267 _MutexEvent = ParkEvent::Allocate(this);
268 _MuxEvent = ParkEvent::Allocate(this);
269
270 #ifdef CHECK_UNHANDLED_OOPS
271 if (CheckUnhandledOops) {
272 _unhandled_oops = new UnhandledOops(this);
273 }
274 #endif // CHECK_UNHANDLED_OOPS
275 #ifdef ASSERT
276 if (UseBiasedLocking) {
277 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
278 assert(this == _real_malloc_address ||
279 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
280 "bug in forced alignment of thread objects");
281 }
282 #endif // ASSERT
283 }
284
285 // Non-inlined version to be used where thread.inline.hpp shouldn't be included.
286 Thread* Thread::current_noinline() {
287 return Thread::current();
288 }
289
290 void Thread::initialize_thread_current() {
291 assert(_thr_current == NULL, "Thread::current already initialized");
292 _thr_current = this;
293 }
294
295 void Thread::clear_thread_current() {
296 _thr_current = NULL;
297 }
298
299 void Thread::record_stack_base_and_size() {
300 set_stack_base(os::current_stack_base());
301 set_stack_size(os::current_stack_size());
302 if (is_Java_thread()) {
303 ((JavaThread*) this)->set_stack_overflow_limit();
304 }
305 // CR 7190089: on Solaris, primordial thread's stack is adjusted
306 // in initialize_thread(). Without the adjustment, stack size is
307 // incorrect if stack is set to unlimited (ulimit -s unlimited).
308 // So far, only Solaris has real implementation of initialize_thread().
309 //
310 // set up any platform-specific state.
311 os::initialize_thread(this);
312
313 #if INCLUDE_NMT
314 // record thread's native stack, stack grows downward
315 address stack_low_addr = stack_base() - stack_size();
316 MemTracker::record_thread_stack(stack_low_addr, stack_size());
317 #endif // INCLUDE_NMT
318 }
319
320
321 Thread::~Thread() {
322 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
323 ObjectSynchronizer::omFlush(this);
324
325 EVENT_THREAD_DESTRUCT(this);
326
327 // stack_base can be NULL if the thread is never started or exited before
328 // record_stack_base_and_size called. Although, we would like to ensure
329 // that all started threads do call record_stack_base_and_size(), there is
330 // not proper way to enforce that.
331 #if INCLUDE_NMT
332 if (_stack_base != NULL) {
333 address low_stack_addr = stack_base() - stack_size();
334 MemTracker::release_thread_stack(low_stack_addr, stack_size());
335 #ifdef ASSERT
336 set_stack_base(NULL);
337 #endif
338 }
339 #endif // INCLUDE_NMT
340
341 // deallocate data structures
342 delete resource_area();
343 // since the handle marks are using the handle area, we have to deallocated the root
344 // handle mark before deallocating the thread's handle area,
345 assert(last_handle_mark() != NULL, "check we have an element");
346 delete last_handle_mark();
347 assert(last_handle_mark() == NULL, "check we have reached the end");
348
349 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
350 // We NULL out the fields for good hygiene.
351 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
352 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
353 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
354 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
355
356 delete handle_area();
357 delete metadata_handles();
358
359 // osthread() can be NULL, if creation of thread failed.
360 if (osthread() != NULL) os::free_thread(osthread());
361
362 delete _SR_lock;
363
364 // clear Thread::current if thread is deleting itself.
365 // Needed to ensure JNI correctly detects non-attached threads.
366 if (this == Thread::current()) {
367 clear_thread_current();
368 }
369
370 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
371 }
372
373 // NOTE: dummy function for assertion purpose.
374 void Thread::run() {
375 ShouldNotReachHere();
376 }
377
378 #ifdef ASSERT
379 // Private method to check for dangling thread pointer
380 void check_for_dangling_thread_pointer(Thread *thread) {
381 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
382 "possibility of dangling Thread pointer");
383 }
384 #endif
385
386 ThreadPriority Thread::get_priority(const Thread* const thread) {
387 ThreadPriority priority;
388 // Can return an error!
389 (void)os::get_priority(thread, priority);
390 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
391 return priority;
392 }
393
394 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
395 debug_only(check_for_dangling_thread_pointer(thread);)
396 // Can return an error!
397 (void)os::set_priority(thread, priority);
398 }
399
400
401 void Thread::start(Thread* thread) {
402 // Start is different from resume in that its safety is guaranteed by context or
403 // being called from a Java method synchronized on the Thread object.
404 if (!DisableStartThread) {
405 if (thread->is_Java_thread()) {
406 // Initialize the thread state to RUNNABLE before starting this thread.
407 // Can not set it after the thread started because we do not know the
408 // exact thread state at that time. It could be in MONITOR_WAIT or
409 // in SLEEPING or some other state.
410 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
411 java_lang_Thread::RUNNABLE);
412 }
413 os::start_thread(thread);
414 }
415 }
416
417 // Enqueue a VM_Operation to do the job for us - sometime later
418 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
419 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
420 VMThread::execute(vm_stop);
421 }
422
423
424 // Check if an external suspend request has completed (or has been
425 // cancelled). Returns true if the thread is externally suspended and
426 // false otherwise.
427 //
428 // The bits parameter returns information about the code path through
429 // the routine. Useful for debugging:
430 //
431 // set in is_ext_suspend_completed():
432 // 0x00000001 - routine was entered
433 // 0x00000010 - routine return false at end
434 // 0x00000100 - thread exited (return false)
435 // 0x00000200 - suspend request cancelled (return false)
436 // 0x00000400 - thread suspended (return true)
437 // 0x00001000 - thread is in a suspend equivalent state (return true)
438 // 0x00002000 - thread is native and walkable (return true)
439 // 0x00004000 - thread is native_trans and walkable (needed retry)
440 //
441 // set in wait_for_ext_suspend_completion():
442 // 0x00010000 - routine was entered
443 // 0x00020000 - suspend request cancelled before loop (return false)
444 // 0x00040000 - thread suspended before loop (return true)
445 // 0x00080000 - suspend request cancelled in loop (return false)
446 // 0x00100000 - thread suspended in loop (return true)
447 // 0x00200000 - suspend not completed during retry loop (return false)
448
449 // Helper class for tracing suspend wait debug bits.
450 //
451 // 0x00000100 indicates that the target thread exited before it could
452 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
453 // 0x00080000 each indicate a cancelled suspend request so they don't
454 // count as wait failures either.
455 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
456
457 class TraceSuspendDebugBits : public StackObj {
458 private:
459 JavaThread * jt;
460 bool is_wait;
461 bool called_by_wait; // meaningful when !is_wait
462 uint32_t * bits;
463
464 public:
465 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
466 uint32_t *_bits) {
467 jt = _jt;
468 is_wait = _is_wait;
469 called_by_wait = _called_by_wait;
470 bits = _bits;
471 }
472
473 ~TraceSuspendDebugBits() {
474 if (!is_wait) {
475 #if 1
476 // By default, don't trace bits for is_ext_suspend_completed() calls.
477 // That trace is very chatty.
478 return;
479 #else
480 if (!called_by_wait) {
481 // If tracing for is_ext_suspend_completed() is enabled, then only
482 // trace calls to it from wait_for_ext_suspend_completion()
483 return;
484 }
485 #endif
486 }
487
488 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
489 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
490 MutexLocker ml(Threads_lock); // needed for get_thread_name()
491 ResourceMark rm;
492
493 tty->print_cr(
494 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
495 jt->get_thread_name(), *bits);
496
497 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
498 }
499 }
500 }
501 };
502 #undef DEBUG_FALSE_BITS
503
504
505 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
506 uint32_t *bits) {
507 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
508
509 bool did_trans_retry = false; // only do thread_in_native_trans retry once
510 bool do_trans_retry; // flag to force the retry
511
512 *bits |= 0x00000001;
513
514 do {
515 do_trans_retry = false;
516
517 if (is_exiting()) {
518 // Thread is in the process of exiting. This is always checked
519 // first to reduce the risk of dereferencing a freed JavaThread.
520 *bits |= 0x00000100;
521 return false;
522 }
523
524 if (!is_external_suspend()) {
525 // Suspend request is cancelled. This is always checked before
526 // is_ext_suspended() to reduce the risk of a rogue resume
527 // confusing the thread that made the suspend request.
528 *bits |= 0x00000200;
529 return false;
530 }
531
532 if (is_ext_suspended()) {
533 // thread is suspended
534 *bits |= 0x00000400;
535 return true;
536 }
537
538 // Now that we no longer do hard suspends of threads running
539 // native code, the target thread can be changing thread state
540 // while we are in this routine:
541 //
542 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
543 //
544 // We save a copy of the thread state as observed at this moment
545 // and make our decision about suspend completeness based on the
546 // copy. This closes the race where the thread state is seen as
547 // _thread_in_native_trans in the if-thread_blocked check, but is
548 // seen as _thread_blocked in if-thread_in_native_trans check.
549 JavaThreadState save_state = thread_state();
550
551 if (save_state == _thread_blocked && is_suspend_equivalent()) {
552 // If the thread's state is _thread_blocked and this blocking
553 // condition is known to be equivalent to a suspend, then we can
554 // consider the thread to be externally suspended. This means that
555 // the code that sets _thread_blocked has been modified to do
556 // self-suspension if the blocking condition releases. We also
557 // used to check for CONDVAR_WAIT here, but that is now covered by
558 // the _thread_blocked with self-suspension check.
559 //
560 // Return true since we wouldn't be here unless there was still an
561 // external suspend request.
562 *bits |= 0x00001000;
563 return true;
564 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
565 // Threads running native code will self-suspend on native==>VM/Java
566 // transitions. If its stack is walkable (should always be the case
567 // unless this function is called before the actual java_suspend()
568 // call), then the wait is done.
569 *bits |= 0x00002000;
570 return true;
571 } else if (!called_by_wait && !did_trans_retry &&
572 save_state == _thread_in_native_trans &&
573 frame_anchor()->walkable()) {
574 // The thread is transitioning from thread_in_native to another
575 // thread state. check_safepoint_and_suspend_for_native_trans()
576 // will force the thread to self-suspend. If it hasn't gotten
577 // there yet we may have caught the thread in-between the native
578 // code check above and the self-suspend. Lucky us. If we were
579 // called by wait_for_ext_suspend_completion(), then it
580 // will be doing the retries so we don't have to.
581 //
582 // Since we use the saved thread state in the if-statement above,
583 // there is a chance that the thread has already transitioned to
584 // _thread_blocked by the time we get here. In that case, we will
585 // make a single unnecessary pass through the logic below. This
586 // doesn't hurt anything since we still do the trans retry.
587
588 *bits |= 0x00004000;
589
590 // Once the thread leaves thread_in_native_trans for another
591 // thread state, we break out of this retry loop. We shouldn't
592 // need this flag to prevent us from getting back here, but
593 // sometimes paranoia is good.
594 did_trans_retry = true;
595
596 // We wait for the thread to transition to a more usable state.
597 for (int i = 1; i <= SuspendRetryCount; i++) {
598 // We used to do an "os::yield_all(i)" call here with the intention
599 // that yielding would increase on each retry. However, the parameter
600 // is ignored on Linux which means the yield didn't scale up. Waiting
601 // on the SR_lock below provides a much more predictable scale up for
602 // the delay. It also provides a simple/direct point to check for any
603 // safepoint requests from the VMThread
604
605 // temporarily drops SR_lock while doing wait with safepoint check
606 // (if we're a JavaThread - the WatcherThread can also call this)
607 // and increase delay with each retry
608 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
609
610 // check the actual thread state instead of what we saved above
611 if (thread_state() != _thread_in_native_trans) {
612 // the thread has transitioned to another thread state so
613 // try all the checks (except this one) one more time.
614 do_trans_retry = true;
615 break;
616 }
617 } // end retry loop
618
619
620 }
621 } while (do_trans_retry);
622
623 *bits |= 0x00000010;
624 return false;
625 }
626
627 // Wait for an external suspend request to complete (or be cancelled).
628 // Returns true if the thread is externally suspended and false otherwise.
629 //
630 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
631 uint32_t *bits) {
632 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
633 false /* !called_by_wait */, bits);
634
635 // local flag copies to minimize SR_lock hold time
636 bool is_suspended;
637 bool pending;
638 uint32_t reset_bits;
639
640 // set a marker so is_ext_suspend_completed() knows we are the caller
641 *bits |= 0x00010000;
642
643 // We use reset_bits to reinitialize the bits value at the top of
644 // each retry loop. This allows the caller to make use of any
645 // unused bits for their own marking purposes.
646 reset_bits = *bits;
647
648 {
649 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
650 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
651 delay, bits);
652 pending = is_external_suspend();
653 }
654 // must release SR_lock to allow suspension to complete
655
656 if (!pending) {
657 // A cancelled suspend request is the only false return from
658 // is_ext_suspend_completed() that keeps us from entering the
659 // retry loop.
660 *bits |= 0x00020000;
661 return false;
662 }
663
664 if (is_suspended) {
665 *bits |= 0x00040000;
666 return true;
667 }
668
669 for (int i = 1; i <= retries; i++) {
670 *bits = reset_bits; // reinit to only track last retry
671
672 // We used to do an "os::yield_all(i)" call here with the intention
673 // that yielding would increase on each retry. However, the parameter
674 // is ignored on Linux which means the yield didn't scale up. Waiting
675 // on the SR_lock below provides a much more predictable scale up for
676 // the delay. It also provides a simple/direct point to check for any
677 // safepoint requests from the VMThread
678
679 {
680 MutexLocker ml(SR_lock());
681 // wait with safepoint check (if we're a JavaThread - the WatcherThread
682 // can also call this) and increase delay with each retry
683 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
684
685 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
686 delay, bits);
687
688 // It is possible for the external suspend request to be cancelled
689 // (by a resume) before the actual suspend operation is completed.
690 // Refresh our local copy to see if we still need to wait.
691 pending = is_external_suspend();
692 }
693
694 if (!pending) {
695 // A cancelled suspend request is the only false return from
696 // is_ext_suspend_completed() that keeps us from staying in the
697 // retry loop.
698 *bits |= 0x00080000;
699 return false;
700 }
701
702 if (is_suspended) {
703 *bits |= 0x00100000;
704 return true;
705 }
706 } // end retry loop
707
708 // thread did not suspend after all our retries
709 *bits |= 0x00200000;
710 return false;
711 }
712
713 #ifndef PRODUCT
714 void JavaThread::record_jump(address target, address instr, const char* file,
715 int line) {
716
717 // This should not need to be atomic as the only way for simultaneous
718 // updates is via interrupts. Even then this should be rare or non-existent
719 // and we don't care that much anyway.
720
721 int index = _jmp_ring_index;
722 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
723 _jmp_ring[index]._target = (intptr_t) target;
724 _jmp_ring[index]._instruction = (intptr_t) instr;
725 _jmp_ring[index]._file = file;
726 _jmp_ring[index]._line = line;
727 }
728 #endif // PRODUCT
729
730 // Called by flat profiler
731 // Callers have already called wait_for_ext_suspend_completion
732 // The assertion for that is currently too complex to put here:
733 bool JavaThread::profile_last_Java_frame(frame* _fr) {
734 bool gotframe = false;
735 // self suspension saves needed state.
736 if (has_last_Java_frame() && _anchor.walkable()) {
737 *_fr = pd_last_frame();
738 gotframe = true;
739 }
740 return gotframe;
741 }
742
743 void Thread::interrupt(Thread* thread) {
744 debug_only(check_for_dangling_thread_pointer(thread);)
745 os::interrupt(thread);
746 }
747
748 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
749 debug_only(check_for_dangling_thread_pointer(thread);)
750 // Note: If clear_interrupted==false, this simply fetches and
751 // returns the value of the field osthread()->interrupted().
752 return os::is_interrupted(thread, clear_interrupted);
753 }
754
755
756 // GC Support
757 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
758 jint thread_parity = _oops_do_parity;
759 if (thread_parity != strong_roots_parity) {
760 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
761 if (res == thread_parity) {
762 return true;
763 } else {
764 guarantee(res == strong_roots_parity, "Or else what?");
765 return false;
766 }
767 }
768 return false;
769 }
770
771 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
772 active_handles()->oops_do(f);
773 // Do oop for ThreadShadow
774 f->do_oop((oop*)&_pending_exception);
775 handle_area()->oops_do(f);
776 }
777
778 void Thread::nmethods_do(CodeBlobClosure* cf) {
779 // no nmethods in a generic thread...
780 }
781
782 void Thread::metadata_handles_do(void f(Metadata*)) {
783 // Only walk the Handles in Thread.
784 if (metadata_handles() != NULL) {
785 for (int i = 0; i< metadata_handles()->length(); i++) {
786 f(metadata_handles()->at(i));
787 }
788 }
789 }
790
791 void Thread::print_on(outputStream* st) const {
792 // get_priority assumes osthread initialized
793 if (osthread() != NULL) {
794 int os_prio;
795 if (os::get_native_priority(this, &os_prio) == OS_OK) {
796 st->print("os_prio=%d ", os_prio);
797 }
798 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
799 ext().print_on(st);
800 osthread()->print_on(st);
801 }
802 debug_only(if (WizardMode) print_owned_locks_on(st);)
803 }
804
805 // Thread::print_on_error() is called by fatal error handler. Don't use
806 // any lock or allocate memory.
807 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
808 if (is_VM_thread()) st->print("VMThread");
809 else if (is_Compiler_thread()) st->print("CompilerThread");
810 else if (is_Java_thread()) st->print("JavaThread");
811 else if (is_GC_task_thread()) st->print("GCTaskThread");
812 else if (is_Watcher_thread()) st->print("WatcherThread");
813 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
814 else st->print("Thread");
815
816 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
817 p2i(_stack_base - _stack_size), p2i(_stack_base));
818
819 if (osthread()) {
820 st->print(" [id=%d]", osthread()->thread_id());
821 }
822 }
823
824 #ifdef ASSERT
825 void Thread::print_owned_locks_on(outputStream* st) const {
826 Monitor *cur = _owned_locks;
827 if (cur == NULL) {
828 st->print(" (no locks) ");
829 } else {
830 st->print_cr(" Locks owned:");
831 while (cur) {
832 cur->print_on(st);
833 cur = cur->next();
834 }
835 }
836 }
837
838 static int ref_use_count = 0;
839
840 bool Thread::owns_locks_but_compiled_lock() const {
841 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
842 if (cur != Compile_lock) return true;
843 }
844 return false;
845 }
846
847
848 #endif
849
850 #ifndef PRODUCT
851
852 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
853 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
854 // no threads which allow_vm_block's are held
855 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
856 // Check if current thread is allowed to block at a safepoint
857 if (!(_allow_safepoint_count == 0)) {
858 fatal("Possible safepoint reached by thread that does not allow it");
859 }
860 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
861 fatal("LEAF method calling lock?");
862 }
863
864 #ifdef ASSERT
865 if (potential_vm_operation && is_Java_thread()
866 && !Universe::is_bootstrapping()) {
867 // Make sure we do not hold any locks that the VM thread also uses.
868 // This could potentially lead to deadlocks
869 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
870 // Threads_lock is special, since the safepoint synchronization will not start before this is
871 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
872 // since it is used to transfer control between JavaThreads and the VMThread
873 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
874 if ((cur->allow_vm_block() &&
875 cur != Threads_lock &&
876 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
877 cur != VMOperationRequest_lock &&
878 cur != VMOperationQueue_lock) ||
879 cur->rank() == Mutex::special) {
880 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
881 }
882 }
883 }
884
885 if (GCALotAtAllSafepoints) {
886 // We could enter a safepoint here and thus have a gc
887 InterfaceSupport::check_gc_alot();
888 }
889 #endif
890 }
891 #endif
892
893 bool Thread::is_in_stack(address adr) const {
894 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
895 address end = os::current_stack_pointer();
896 // Allow non Java threads to call this without stack_base
897 if (_stack_base == NULL) return true;
898 if (stack_base() >= adr && adr >= end) return true;
899
900 return false;
901 }
902
903
904 bool Thread::is_in_usable_stack(address adr) const {
905 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
906 size_t usable_stack_size = _stack_size - stack_guard_size;
907
908 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
909 }
910
911
912 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
913 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
914 // used for compilation in the future. If that change is made, the need for these methods
915 // should be revisited, and they should be removed if possible.
916
917 bool Thread::is_lock_owned(address adr) const {
918 return on_local_stack(adr);
919 }
920
921 bool Thread::set_as_starting_thread() {
922 // NOTE: this must be called inside the main thread.
923 return os::create_main_thread((JavaThread*)this);
924 }
925
926 static void initialize_class(Symbol* class_name, TRAPS) {
927 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
928 InstanceKlass::cast(klass)->initialize(CHECK);
929 }
930
931
932 // Creates the initial ThreadGroup
933 static Handle create_initial_thread_group(TRAPS) {
934 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
935 instanceKlassHandle klass (THREAD, k);
936
937 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
938 {
939 JavaValue result(T_VOID);
940 JavaCalls::call_special(&result,
941 system_instance,
942 klass,
943 vmSymbols::object_initializer_name(),
944 vmSymbols::void_method_signature(),
945 CHECK_NH);
946 }
947 Universe::set_system_thread_group(system_instance());
948
949 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
950 {
951 JavaValue result(T_VOID);
952 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
953 JavaCalls::call_special(&result,
954 main_instance,
955 klass,
956 vmSymbols::object_initializer_name(),
957 vmSymbols::threadgroup_string_void_signature(),
958 system_instance,
959 string,
960 CHECK_NH);
961 }
962 return main_instance;
963 }
964
965 // Creates the initial Thread
966 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
967 TRAPS) {
968 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
969 instanceKlassHandle klass (THREAD, k);
970 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
971
972 java_lang_Thread::set_thread(thread_oop(), thread);
973 java_lang_Thread::set_priority(thread_oop(), NormPriority);
974 thread->set_threadObj(thread_oop());
975
976 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
977
978 JavaValue result(T_VOID);
979 JavaCalls::call_special(&result, thread_oop,
980 klass,
981 vmSymbols::object_initializer_name(),
982 vmSymbols::threadgroup_string_void_signature(),
983 thread_group,
984 string,
985 CHECK_NULL);
986 return thread_oop();
987 }
988
989 static void call_initializeSystemClass(TRAPS) {
990 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
991 instanceKlassHandle klass (THREAD, k);
992
993 JavaValue result(T_VOID);
994 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
995 vmSymbols::void_method_signature(), CHECK);
996 }
997
998 char java_runtime_name[128] = "";
999 char java_runtime_version[128] = "";
1000
1001 // extract the JRE name from sun.misc.Version.java_runtime_name
1002 static const char* get_java_runtime_name(TRAPS) {
1003 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1004 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1005 fieldDescriptor fd;
1006 bool found = k != NULL &&
1007 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1008 vmSymbols::string_signature(), &fd);
1009 if (found) {
1010 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1011 if (name_oop == NULL) {
1012 return NULL;
1013 }
1014 const char* name = java_lang_String::as_utf8_string(name_oop,
1015 java_runtime_name,
1016 sizeof(java_runtime_name));
1017 return name;
1018 } else {
1019 return NULL;
1020 }
1021 }
1022
1023 // extract the JRE version from sun.misc.Version.java_runtime_version
1024 static const char* get_java_runtime_version(TRAPS) {
1025 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1026 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1027 fieldDescriptor fd;
1028 bool found = k != NULL &&
1029 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1030 vmSymbols::string_signature(), &fd);
1031 if (found) {
1032 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1033 if (name_oop == NULL) {
1034 return NULL;
1035 }
1036 const char* name = java_lang_String::as_utf8_string(name_oop,
1037 java_runtime_version,
1038 sizeof(java_runtime_version));
1039 return name;
1040 } else {
1041 return NULL;
1042 }
1043 }
1044
1045 // General purpose hook into Java code, run once when the VM is initialized.
1046 // The Java library method itself may be changed independently from the VM.
1047 static void call_postVMInitHook(TRAPS) {
1048 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1049 instanceKlassHandle klass (THREAD, k);
1050 if (klass.not_null()) {
1051 JavaValue result(T_VOID);
1052 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1053 vmSymbols::void_method_signature(),
1054 CHECK);
1055 }
1056 }
1057
1058 static void reset_vm_info_property(TRAPS) {
1059 // the vm info string
1060 ResourceMark rm(THREAD);
1061 const char *vm_info = VM_Version::vm_info_string();
1062
1063 // java.lang.System class
1064 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1065 instanceKlassHandle klass (THREAD, k);
1066
1067 // setProperty arguments
1068 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1069 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1070
1071 // return value
1072 JavaValue r(T_OBJECT);
1073
1074 // public static String setProperty(String key, String value);
1075 JavaCalls::call_static(&r,
1076 klass,
1077 vmSymbols::setProperty_name(),
1078 vmSymbols::string_string_string_signature(),
1079 key_str,
1080 value_str,
1081 CHECK);
1082 }
1083
1084
1085 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1086 bool daemon, TRAPS) {
1087 assert(thread_group.not_null(), "thread group should be specified");
1088 assert(threadObj() == NULL, "should only create Java thread object once");
1089
1090 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1091 instanceKlassHandle klass (THREAD, k);
1092 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1093
1094 java_lang_Thread::set_thread(thread_oop(), this);
1095 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1096 set_threadObj(thread_oop());
1097
1098 JavaValue result(T_VOID);
1099 if (thread_name != NULL) {
1100 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1101 // Thread gets assigned specified name and null target
1102 JavaCalls::call_special(&result,
1103 thread_oop,
1104 klass,
1105 vmSymbols::object_initializer_name(),
1106 vmSymbols::threadgroup_string_void_signature(),
1107 thread_group, // Argument 1
1108 name, // Argument 2
1109 THREAD);
1110 } else {
1111 // Thread gets assigned name "Thread-nnn" and null target
1112 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1113 JavaCalls::call_special(&result,
1114 thread_oop,
1115 klass,
1116 vmSymbols::object_initializer_name(),
1117 vmSymbols::threadgroup_runnable_void_signature(),
1118 thread_group, // Argument 1
1119 Handle(), // Argument 2
1120 THREAD);
1121 }
1122
1123
1124 if (daemon) {
1125 java_lang_Thread::set_daemon(thread_oop());
1126 }
1127
1128 if (HAS_PENDING_EXCEPTION) {
1129 return;
1130 }
1131
1132 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1133 Handle threadObj(THREAD, this->threadObj());
1134
1135 JavaCalls::call_special(&result,
1136 thread_group,
1137 group,
1138 vmSymbols::add_method_name(),
1139 vmSymbols::thread_void_signature(),
1140 threadObj, // Arg 1
1141 THREAD);
1142 }
1143
1144 // NamedThread -- non-JavaThread subclasses with multiple
1145 // uniquely named instances should derive from this.
1146 NamedThread::NamedThread() : Thread() {
1147 _name = NULL;
1148 _processed_thread = NULL;
1149 _gc_id = GCId::undefined();
1150 }
1151
1152 NamedThread::~NamedThread() {
1153 if (_name != NULL) {
1154 FREE_C_HEAP_ARRAY(char, _name);
1155 _name = NULL;
1156 }
1157 }
1158
1159 void NamedThread::set_name(const char* format, ...) {
1160 guarantee(_name == NULL, "Only get to set name once.");
1161 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1162 guarantee(_name != NULL, "alloc failure");
1163 va_list ap;
1164 va_start(ap, format);
1165 jio_vsnprintf(_name, max_name_len, format, ap);
1166 va_end(ap);
1167 }
1168
1169 void NamedThread::initialize_named_thread() {
1170 set_native_thread_name(name());
1171 }
1172
1173 void NamedThread::print_on(outputStream* st) const {
1174 st->print("\"%s\" ", name());
1175 Thread::print_on(st);
1176 st->cr();
1177 }
1178
1179
1180 // ======= WatcherThread ========
1181
1182 // The watcher thread exists to simulate timer interrupts. It should
1183 // be replaced by an abstraction over whatever native support for
1184 // timer interrupts exists on the platform.
1185
1186 WatcherThread* WatcherThread::_watcher_thread = NULL;
1187 bool WatcherThread::_startable = false;
1188 volatile bool WatcherThread::_should_terminate = false;
1189
1190 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1191 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1192 if (os::create_thread(this, os::watcher_thread)) {
1193 _watcher_thread = this;
1194
1195 // Set the watcher thread to the highest OS priority which should not be
1196 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1197 // is created. The only normal thread using this priority is the reference
1198 // handler thread, which runs for very short intervals only.
1199 // If the VMThread's priority is not lower than the WatcherThread profiling
1200 // will be inaccurate.
1201 os::set_priority(this, MaxPriority);
1202 if (!DisableStartThread) {
1203 os::start_thread(this);
1204 }
1205 }
1206 }
1207
1208 int WatcherThread::sleep() const {
1209 // The WatcherThread does not participate in the safepoint protocol
1210 // for the PeriodicTask_lock because it is not a JavaThread.
1211 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1212
1213 if (_should_terminate) {
1214 // check for termination before we do any housekeeping or wait
1215 return 0; // we did not sleep.
1216 }
1217
1218 // remaining will be zero if there are no tasks,
1219 // causing the WatcherThread to sleep until a task is
1220 // enrolled
1221 int remaining = PeriodicTask::time_to_wait();
1222 int time_slept = 0;
1223
1224 // we expect this to timeout - we only ever get unparked when
1225 // we should terminate or when a new task has been enrolled
1226 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1227
1228 jlong time_before_loop = os::javaTimeNanos();
1229
1230 while (true) {
1231 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1232 remaining);
1233 jlong now = os::javaTimeNanos();
1234
1235 if (remaining == 0) {
1236 // if we didn't have any tasks we could have waited for a long time
1237 // consider the time_slept zero and reset time_before_loop
1238 time_slept = 0;
1239 time_before_loop = now;
1240 } else {
1241 // need to recalculate since we might have new tasks in _tasks
1242 time_slept = (int) ((now - time_before_loop) / 1000000);
1243 }
1244
1245 // Change to task list or spurious wakeup of some kind
1246 if (timedout || _should_terminate) {
1247 break;
1248 }
1249
1250 remaining = PeriodicTask::time_to_wait();
1251 if (remaining == 0) {
1252 // Last task was just disenrolled so loop around and wait until
1253 // another task gets enrolled
1254 continue;
1255 }
1256
1257 remaining -= time_slept;
1258 if (remaining <= 0) {
1259 break;
1260 }
1261 }
1262
1263 return time_slept;
1264 }
1265
1266 void WatcherThread::run() {
1267 assert(this == watcher_thread(), "just checking");
1268
1269 this->record_stack_base_and_size();
1270 this->set_native_thread_name(this->name());
1271 this->set_active_handles(JNIHandleBlock::allocate_block());
1272 while (true) {
1273 assert(watcher_thread() == Thread::current(), "thread consistency check");
1274 assert(watcher_thread() == this, "thread consistency check");
1275
1276 // Calculate how long it'll be until the next PeriodicTask work
1277 // should be done, and sleep that amount of time.
1278 int time_waited = sleep();
1279
1280 if (is_error_reported()) {
1281 // A fatal error has happened, the error handler(VMError::report_and_die)
1282 // should abort JVM after creating an error log file. However in some
1283 // rare cases, the error handler itself might deadlock. Here we try to
1284 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1285 //
1286 // This code is in WatcherThread because WatcherThread wakes up
1287 // periodically so the fatal error handler doesn't need to do anything;
1288 // also because the WatcherThread is less likely to crash than other
1289 // threads.
1290
1291 for (;;) {
1292 if (!ShowMessageBoxOnError
1293 && (OnError == NULL || OnError[0] == '\0')
1294 && Arguments::abort_hook() == NULL) {
1295 os::sleep(this, ErrorLogTimeout * 60 * 1000, false);
1296 fdStream err(defaultStream::output_fd());
1297 err.print_raw_cr("# [ timer expired, abort... ]");
1298 // skip atexit/vm_exit/vm_abort hooks
1299 os::die();
1300 }
1301
1302 // Wake up 5 seconds later, the fatal handler may reset OnError or
1303 // ShowMessageBoxOnError when it is ready to abort.
1304 os::sleep(this, 5 * 1000, false);
1305 }
1306 }
1307
1308 if (_should_terminate) {
1309 // check for termination before posting the next tick
1310 break;
1311 }
1312
1313 PeriodicTask::real_time_tick(time_waited);
1314 }
1315
1316 // Signal that it is terminated
1317 {
1318 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1319 _watcher_thread = NULL;
1320 Terminator_lock->notify();
1321 }
1322 }
1323
1324 void WatcherThread::start() {
1325 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1326
1327 if (watcher_thread() == NULL && _startable) {
1328 _should_terminate = false;
1329 // Create the single instance of WatcherThread
1330 new WatcherThread();
1331 }
1332 }
1333
1334 void WatcherThread::make_startable() {
1335 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1336 _startable = true;
1337 }
1338
1339 void WatcherThread::stop() {
1340 {
1341 // Follow normal safepoint aware lock enter protocol since the
1342 // WatcherThread is stopped by another JavaThread.
1343 MutexLocker ml(PeriodicTask_lock);
1344 _should_terminate = true;
1345
1346 WatcherThread* watcher = watcher_thread();
1347 if (watcher != NULL) {
1348 // unpark the WatcherThread so it can see that it should terminate
1349 watcher->unpark();
1350 }
1351 }
1352
1353 MutexLocker mu(Terminator_lock);
1354
1355 while (watcher_thread() != NULL) {
1356 // This wait should make safepoint checks, wait without a timeout,
1357 // and wait as a suspend-equivalent condition.
1358 //
1359 // Note: If the FlatProfiler is running, then this thread is waiting
1360 // for the WatcherThread to terminate and the WatcherThread, via the
1361 // FlatProfiler task, is waiting for the external suspend request on
1362 // this thread to complete. wait_for_ext_suspend_completion() will
1363 // eventually timeout, but that takes time. Making this wait a
1364 // suspend-equivalent condition solves that timeout problem.
1365 //
1366 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1367 Mutex::_as_suspend_equivalent_flag);
1368 }
1369 }
1370
1371 void WatcherThread::unpark() {
1372 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1373 PeriodicTask_lock->notify();
1374 }
1375
1376 void WatcherThread::print_on(outputStream* st) const {
1377 st->print("\"%s\" ", name());
1378 Thread::print_on(st);
1379 st->cr();
1380 }
1381
1382 // ======= JavaThread ========
1383
1384 #if INCLUDE_JVMCI
1385
1386 jlong* JavaThread::_jvmci_old_thread_counters;
1387
1388 bool jvmci_counters_include(JavaThread* thread) {
1389 oop threadObj = thread->threadObj();
1390 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1391 }
1392
1393 void JavaThread::collect_counters(typeArrayOop array) {
1394 if (JVMCICounterSize > 0) {
1395 MutexLocker tl(Threads_lock);
1396 for (int i = 0; i < array->length(); i++) {
1397 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1398 }
1399 for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) {
1400 if (jvmci_counters_include(tp)) {
1401 for (int i = 0; i < array->length(); i++) {
1402 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1403 }
1404 }
1405 }
1406 }
1407 }
1408
1409 #endif // INCLUDE_JVMCI
1410
1411 // A JavaThread is a normal Java thread
1412
1413 void JavaThread::initialize() {
1414 // Initialize fields
1415
1416 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1417 set_claimed_par_id(UINT_MAX);
1418
1419 set_saved_exception_pc(NULL);
1420 set_threadObj(NULL);
1421 _anchor.clear();
1422 set_entry_point(NULL);
1423 set_jni_functions(jni_functions());
1424 set_callee_target(NULL);
1425 set_vm_result(NULL);
1426 set_vm_result_2(NULL);
1427 set_vframe_array_head(NULL);
1428 set_vframe_array_last(NULL);
1429 set_deferred_locals(NULL);
1430 set_deopt_mark(NULL);
1431 set_deopt_nmethod(NULL);
1432 clear_must_deopt_id();
1433 set_monitor_chunks(NULL);
1434 set_next(NULL);
1435 set_thread_state(_thread_new);
1436 _terminated = _not_terminated;
1437 _privileged_stack_top = NULL;
1438 _array_for_gc = NULL;
1439 _suspend_equivalent = false;
1440 _in_deopt_handler = 0;
1441 _doing_unsafe_access = false;
1442 _stack_guard_state = stack_guard_unused;
1443 #if INCLUDE_JVMCI
1444 _pending_monitorenter = false;
1445 _pending_deoptimization = -1;
1446 _pending_failed_speculation = NULL;
1447 _pending_transfer_to_interpreter = false;
1448 _jvmci._alternate_call_target = NULL;
1449 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1450 if (JVMCICounterSize > 0) {
1451 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1452 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1453 } else {
1454 _jvmci_counters = NULL;
1455 }
1456 #endif // INCLUDE_JVMCI
1457 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1458 _exception_pc = 0;
1459 _exception_handler_pc = 0;
1460 _is_method_handle_return = 0;
1461 _jvmti_thread_state= NULL;
1462 _should_post_on_exceptions_flag = JNI_FALSE;
1463 _jvmti_get_loaded_classes_closure = NULL;
1464 _interp_only_mode = 0;
1465 _special_runtime_exit_condition = _no_async_condition;
1466 _pending_async_exception = NULL;
1467 _thread_stat = NULL;
1468 _thread_stat = new ThreadStatistics();
1469 _blocked_on_compilation = false;
1470 _jni_active_critical = 0;
1471 _pending_jni_exception_check_fn = NULL;
1472 _do_not_unlock_if_synchronized = false;
1473 _cached_monitor_info = NULL;
1474 _parker = Parker::Allocate(this);
1475
1476 #ifndef PRODUCT
1477 _jmp_ring_index = 0;
1478 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1479 record_jump(NULL, NULL, NULL, 0);
1480 }
1481 #endif // PRODUCT
1482
1483 set_thread_profiler(NULL);
1484 if (FlatProfiler::is_active()) {
1485 // This is where we would decide to either give each thread it's own profiler
1486 // or use one global one from FlatProfiler,
1487 // or up to some count of the number of profiled threads, etc.
1488 ThreadProfiler* pp = new ThreadProfiler();
1489 pp->engage();
1490 set_thread_profiler(pp);
1491 }
1492
1493 // Setup safepoint state info for this thread
1494 ThreadSafepointState::create(this);
1495
1496 debug_only(_java_call_counter = 0);
1497
1498 // JVMTI PopFrame support
1499 _popframe_condition = popframe_inactive;
1500 _popframe_preserved_args = NULL;
1501 _popframe_preserved_args_size = 0;
1502 _frames_to_pop_failed_realloc = 0;
1503
1504 pd_initialize();
1505 }
1506
1507 #if INCLUDE_ALL_GCS
1508 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1509 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1510 #endif // INCLUDE_ALL_GCS
1511
1512 JavaThread::JavaThread(bool is_attaching_via_jni) :
1513 Thread()
1514 #if INCLUDE_ALL_GCS
1515 , _satb_mark_queue(&_satb_mark_queue_set),
1516 _dirty_card_queue(&_dirty_card_queue_set)
1517 #endif // INCLUDE_ALL_GCS
1518 {
1519 initialize();
1520 if (is_attaching_via_jni) {
1521 _jni_attach_state = _attaching_via_jni;
1522 } else {
1523 _jni_attach_state = _not_attaching_via_jni;
1524 }
1525 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1526 }
1527
1528 bool JavaThread::reguard_stack(address cur_sp) {
1529 if (_stack_guard_state != stack_guard_yellow_disabled) {
1530 return true; // Stack already guarded or guard pages not needed.
1531 }
1532
1533 if (register_stack_overflow()) {
1534 // For those architectures which have separate register and
1535 // memory stacks, we must check the register stack to see if
1536 // it has overflowed.
1537 return false;
1538 }
1539
1540 // Java code never executes within the yellow zone: the latter is only
1541 // there to provoke an exception during stack banging. If java code
1542 // is executing there, either StackShadowPages should be larger, or
1543 // some exception code in c1, c2 or the interpreter isn't unwinding
1544 // when it should.
1545 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1546
1547 enable_stack_yellow_zone();
1548 return true;
1549 }
1550
1551 bool JavaThread::reguard_stack(void) {
1552 return reguard_stack(os::current_stack_pointer());
1553 }
1554
1555
1556 void JavaThread::block_if_vm_exited() {
1557 if (_terminated == _vm_exited) {
1558 // _vm_exited is set at safepoint, and Threads_lock is never released
1559 // we will block here forever
1560 Threads_lock->lock_without_safepoint_check();
1561 ShouldNotReachHere();
1562 }
1563 }
1564
1565
1566 // Remove this ifdef when C1 is ported to the compiler interface.
1567 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1568 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1569
1570 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1571 Thread()
1572 #if INCLUDE_ALL_GCS
1573 , _satb_mark_queue(&_satb_mark_queue_set),
1574 _dirty_card_queue(&_dirty_card_queue_set)
1575 #endif // INCLUDE_ALL_GCS
1576 {
1577 initialize();
1578 _jni_attach_state = _not_attaching_via_jni;
1579 set_entry_point(entry_point);
1580 // Create the native thread itself.
1581 // %note runtime_23
1582 os::ThreadType thr_type = os::java_thread;
1583 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1584 os::java_thread;
1585 os::create_thread(this, thr_type, stack_sz);
1586 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1587 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1588 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1589 // the exception consists of creating the exception object & initializing it, initialization
1590 // will leave the VM via a JavaCall and then all locks must be unlocked).
1591 //
1592 // The thread is still suspended when we reach here. Thread must be explicit started
1593 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1594 // by calling Threads:add. The reason why this is not done here, is because the thread
1595 // object must be fully initialized (take a look at JVM_Start)
1596 }
1597
1598 JavaThread::~JavaThread() {
1599
1600 // JSR166 -- return the parker to the free list
1601 Parker::Release(_parker);
1602 _parker = NULL;
1603
1604 // Free any remaining previous UnrollBlock
1605 vframeArray* old_array = vframe_array_last();
1606
1607 if (old_array != NULL) {
1608 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1609 old_array->set_unroll_block(NULL);
1610 delete old_info;
1611 delete old_array;
1612 }
1613
1614 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1615 if (deferred != NULL) {
1616 // This can only happen if thread is destroyed before deoptimization occurs.
1617 assert(deferred->length() != 0, "empty array!");
1618 do {
1619 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1620 deferred->remove_at(0);
1621 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1622 delete dlv;
1623 } while (deferred->length() != 0);
1624 delete deferred;
1625 }
1626
1627 // All Java related clean up happens in exit
1628 ThreadSafepointState::destroy(this);
1629 if (_thread_profiler != NULL) delete _thread_profiler;
1630 if (_thread_stat != NULL) delete _thread_stat;
1631
1632 #if INCLUDE_JVMCI
1633 if (JVMCICounterSize > 0) {
1634 if (jvmci_counters_include(this)) {
1635 for (int i = 0; i < JVMCICounterSize; i++) {
1636 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1637 }
1638 }
1639 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1640 }
1641 #endif // INCLUDE_JVMCI
1642 }
1643
1644
1645 // The first routine called by a new Java thread
1646 void JavaThread::run() {
1647 // initialize thread-local alloc buffer related fields
1648 this->initialize_tlab();
1649
1650 // used to test validity of stack trace backs
1651 this->record_base_of_stack_pointer();
1652
1653 // Record real stack base and size.
1654 this->record_stack_base_and_size();
1655
1656 this->create_stack_guard_pages();
1657
1658 this->cache_global_variables();
1659
1660 // Thread is now sufficient initialized to be handled by the safepoint code as being
1661 // in the VM. Change thread state from _thread_new to _thread_in_vm
1662 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1663
1664 assert(JavaThread::current() == this, "sanity check");
1665 assert(!Thread::current()->owns_locks(), "sanity check");
1666
1667 DTRACE_THREAD_PROBE(start, this);
1668
1669 // This operation might block. We call that after all safepoint checks for a new thread has
1670 // been completed.
1671 this->set_active_handles(JNIHandleBlock::allocate_block());
1672
1673 if (JvmtiExport::should_post_thread_life()) {
1674 JvmtiExport::post_thread_start(this);
1675 }
1676
1677 EventThreadStart event;
1678 if (event.should_commit()) {
1679 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1680 event.commit();
1681 }
1682
1683 // We call another function to do the rest so we are sure that the stack addresses used
1684 // from there will be lower than the stack base just computed
1685 thread_main_inner();
1686
1687 // Note, thread is no longer valid at this point!
1688 }
1689
1690
1691 void JavaThread::thread_main_inner() {
1692 assert(JavaThread::current() == this, "sanity check");
1693 assert(this->threadObj() != NULL, "just checking");
1694
1695 // Execute thread entry point unless this thread has a pending exception
1696 // or has been stopped before starting.
1697 // Note: Due to JVM_StopThread we can have pending exceptions already!
1698 if (!this->has_pending_exception() &&
1699 !java_lang_Thread::is_stillborn(this->threadObj())) {
1700 {
1701 ResourceMark rm(this);
1702 this->set_native_thread_name(this->get_thread_name());
1703 }
1704 HandleMark hm(this);
1705 this->entry_point()(this, this);
1706 }
1707
1708 DTRACE_THREAD_PROBE(stop, this);
1709
1710 this->exit(false);
1711 delete this;
1712 }
1713
1714
1715 static void ensure_join(JavaThread* thread) {
1716 // We do not need to grap the Threads_lock, since we are operating on ourself.
1717 Handle threadObj(thread, thread->threadObj());
1718 assert(threadObj.not_null(), "java thread object must exist");
1719 ObjectLocker lock(threadObj, thread);
1720 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1721 thread->clear_pending_exception();
1722 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1723 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1724 // Clear the native thread instance - this makes isAlive return false and allows the join()
1725 // to complete once we've done the notify_all below
1726 java_lang_Thread::set_thread(threadObj(), NULL);
1727 lock.notify_all(thread);
1728 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1729 thread->clear_pending_exception();
1730 }
1731
1732
1733 // For any new cleanup additions, please check to see if they need to be applied to
1734 // cleanup_failed_attach_current_thread as well.
1735 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1736 assert(this == JavaThread::current(), "thread consistency check");
1737
1738 HandleMark hm(this);
1739 Handle uncaught_exception(this, this->pending_exception());
1740 this->clear_pending_exception();
1741 Handle threadObj(this, this->threadObj());
1742 assert(threadObj.not_null(), "Java thread object should be created");
1743
1744 if (get_thread_profiler() != NULL) {
1745 get_thread_profiler()->disengage();
1746 ResourceMark rm;
1747 get_thread_profiler()->print(get_thread_name());
1748 }
1749
1750
1751 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1752 {
1753 EXCEPTION_MARK;
1754
1755 CLEAR_PENDING_EXCEPTION;
1756 }
1757 if (!destroy_vm) {
1758 if (uncaught_exception.not_null()) {
1759 EXCEPTION_MARK;
1760 // Call method Thread.dispatchUncaughtException().
1761 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1762 JavaValue result(T_VOID);
1763 JavaCalls::call_virtual(&result,
1764 threadObj, thread_klass,
1765 vmSymbols::dispatchUncaughtException_name(),
1766 vmSymbols::throwable_void_signature(),
1767 uncaught_exception,
1768 THREAD);
1769 if (HAS_PENDING_EXCEPTION) {
1770 ResourceMark rm(this);
1771 jio_fprintf(defaultStream::error_stream(),
1772 "\nException: %s thrown from the UncaughtExceptionHandler"
1773 " in thread \"%s\"\n",
1774 pending_exception()->klass()->external_name(),
1775 get_thread_name());
1776 CLEAR_PENDING_EXCEPTION;
1777 }
1778 }
1779
1780 // Called before the java thread exit since we want to read info
1781 // from java_lang_Thread object
1782 EventThreadEnd event;
1783 if (event.should_commit()) {
1784 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1785 event.commit();
1786 }
1787
1788 // Call after last event on thread
1789 EVENT_THREAD_EXIT(this);
1790
1791 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1792 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1793 // is deprecated anyhow.
1794 if (!is_Compiler_thread()) {
1795 int count = 3;
1796 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1797 EXCEPTION_MARK;
1798 JavaValue result(T_VOID);
1799 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1800 JavaCalls::call_virtual(&result,
1801 threadObj, thread_klass,
1802 vmSymbols::exit_method_name(),
1803 vmSymbols::void_method_signature(),
1804 THREAD);
1805 CLEAR_PENDING_EXCEPTION;
1806 }
1807 }
1808 // notify JVMTI
1809 if (JvmtiExport::should_post_thread_life()) {
1810 JvmtiExport::post_thread_end(this);
1811 }
1812
1813 // We have notified the agents that we are exiting, before we go on,
1814 // we must check for a pending external suspend request and honor it
1815 // in order to not surprise the thread that made the suspend request.
1816 while (true) {
1817 {
1818 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1819 if (!is_external_suspend()) {
1820 set_terminated(_thread_exiting);
1821 ThreadService::current_thread_exiting(this);
1822 break;
1823 }
1824 // Implied else:
1825 // Things get a little tricky here. We have a pending external
1826 // suspend request, but we are holding the SR_lock so we
1827 // can't just self-suspend. So we temporarily drop the lock
1828 // and then self-suspend.
1829 }
1830
1831 ThreadBlockInVM tbivm(this);
1832 java_suspend_self();
1833
1834 // We're done with this suspend request, but we have to loop around
1835 // and check again. Eventually we will get SR_lock without a pending
1836 // external suspend request and will be able to mark ourselves as
1837 // exiting.
1838 }
1839 // no more external suspends are allowed at this point
1840 } else {
1841 // before_exit() has already posted JVMTI THREAD_END events
1842 }
1843
1844 // Notify waiters on thread object. This has to be done after exit() is called
1845 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1846 // group should have the destroyed bit set before waiters are notified).
1847 ensure_join(this);
1848 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1849
1850 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1851 // held by this thread must be released. The spec does not distinguish
1852 // between JNI-acquired and regular Java monitors. We can only see
1853 // regular Java monitors here if monitor enter-exit matching is broken.
1854 //
1855 // Optionally release any monitors for regular JavaThread exits. This
1856 // is provided as a work around for any bugs in monitor enter-exit
1857 // matching. This can be expensive so it is not enabled by default.
1858 //
1859 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1860 // ObjectSynchronizer::release_monitors_owned_by_thread().
1861 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
1862 // Sanity check even though JNI DetachCurrentThread() would have
1863 // returned JNI_ERR if there was a Java frame. JavaThread exit
1864 // should be done executing Java code by the time we get here.
1865 assert(!this->has_last_Java_frame(),
1866 "should not have a Java frame when detaching or exiting");
1867 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1868 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1869 }
1870
1871 // These things needs to be done while we are still a Java Thread. Make sure that thread
1872 // is in a consistent state, in case GC happens
1873 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1874
1875 if (active_handles() != NULL) {
1876 JNIHandleBlock* block = active_handles();
1877 set_active_handles(NULL);
1878 JNIHandleBlock::release_block(block);
1879 }
1880
1881 if (free_handle_block() != NULL) {
1882 JNIHandleBlock* block = free_handle_block();
1883 set_free_handle_block(NULL);
1884 JNIHandleBlock::release_block(block);
1885 }
1886
1887 // These have to be removed while this is still a valid thread.
1888 remove_stack_guard_pages();
1889
1890 if (UseTLAB) {
1891 tlab().make_parsable(true); // retire TLAB
1892 }
1893
1894 if (JvmtiEnv::environments_might_exist()) {
1895 JvmtiExport::cleanup_thread(this);
1896 }
1897
1898 // We must flush any deferred card marks before removing a thread from
1899 // the list of active threads.
1900 Universe::heap()->flush_deferred_store_barrier(this);
1901 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1902
1903 #if INCLUDE_ALL_GCS
1904 // We must flush the G1-related buffers before removing a thread
1905 // from the list of active threads. We must do this after any deferred
1906 // card marks have been flushed (above) so that any entries that are
1907 // added to the thread's dirty card queue as a result are not lost.
1908 if (UseG1GC) {
1909 flush_barrier_queues();
1910 }
1911 #endif // INCLUDE_ALL_GCS
1912
1913 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1914 Threads::remove(this);
1915 }
1916
1917 #if INCLUDE_ALL_GCS
1918 // Flush G1-related queues.
1919 void JavaThread::flush_barrier_queues() {
1920 satb_mark_queue().flush();
1921 dirty_card_queue().flush();
1922 }
1923
1924 void JavaThread::initialize_queues() {
1925 assert(!SafepointSynchronize::is_at_safepoint(),
1926 "we should not be at a safepoint");
1927
1928 ObjPtrQueue& satb_queue = satb_mark_queue();
1929 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1930 // The SATB queue should have been constructed with its active
1931 // field set to false.
1932 assert(!satb_queue.is_active(), "SATB queue should not be active");
1933 assert(satb_queue.is_empty(), "SATB queue should be empty");
1934 // If we are creating the thread during a marking cycle, we should
1935 // set the active field of the SATB queue to true.
1936 if (satb_queue_set.is_active()) {
1937 satb_queue.set_active(true);
1938 }
1939
1940 DirtyCardQueue& dirty_queue = dirty_card_queue();
1941 // The dirty card queue should have been constructed with its
1942 // active field set to true.
1943 assert(dirty_queue.is_active(), "dirty card queue should be active");
1944 }
1945 #endif // INCLUDE_ALL_GCS
1946
1947 void JavaThread::cleanup_failed_attach_current_thread() {
1948 if (get_thread_profiler() != NULL) {
1949 get_thread_profiler()->disengage();
1950 ResourceMark rm;
1951 get_thread_profiler()->print(get_thread_name());
1952 }
1953
1954 if (active_handles() != NULL) {
1955 JNIHandleBlock* block = active_handles();
1956 set_active_handles(NULL);
1957 JNIHandleBlock::release_block(block);
1958 }
1959
1960 if (free_handle_block() != NULL) {
1961 JNIHandleBlock* block = free_handle_block();
1962 set_free_handle_block(NULL);
1963 JNIHandleBlock::release_block(block);
1964 }
1965
1966 // These have to be removed while this is still a valid thread.
1967 remove_stack_guard_pages();
1968
1969 if (UseTLAB) {
1970 tlab().make_parsable(true); // retire TLAB, if any
1971 }
1972
1973 #if INCLUDE_ALL_GCS
1974 if (UseG1GC) {
1975 flush_barrier_queues();
1976 }
1977 #endif // INCLUDE_ALL_GCS
1978
1979 Threads::remove(this);
1980 delete this;
1981 }
1982
1983
1984
1985
1986 JavaThread* JavaThread::active() {
1987 Thread* thread = Thread::current();
1988 assert(thread != NULL, "just checking");
1989 if (thread->is_Java_thread()) {
1990 return (JavaThread*) thread;
1991 } else {
1992 assert(thread->is_VM_thread(), "this must be a vm thread");
1993 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1994 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1995 assert(ret->is_Java_thread(), "must be a Java thread");
1996 return ret;
1997 }
1998 }
1999
2000 bool JavaThread::is_lock_owned(address adr) const {
2001 if (Thread::is_lock_owned(adr)) return true;
2002
2003 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2004 if (chunk->contains(adr)) return true;
2005 }
2006
2007 return false;
2008 }
2009
2010
2011 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2012 chunk->set_next(monitor_chunks());
2013 set_monitor_chunks(chunk);
2014 }
2015
2016 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2017 guarantee(monitor_chunks() != NULL, "must be non empty");
2018 if (monitor_chunks() == chunk) {
2019 set_monitor_chunks(chunk->next());
2020 } else {
2021 MonitorChunk* prev = monitor_chunks();
2022 while (prev->next() != chunk) prev = prev->next();
2023 prev->set_next(chunk->next());
2024 }
2025 }
2026
2027 // JVM support.
2028
2029 // Note: this function shouldn't block if it's called in
2030 // _thread_in_native_trans state (such as from
2031 // check_special_condition_for_native_trans()).
2032 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2033
2034 if (has_last_Java_frame() && has_async_condition()) {
2035 // If we are at a polling page safepoint (not a poll return)
2036 // then we must defer async exception because live registers
2037 // will be clobbered by the exception path. Poll return is
2038 // ok because the call we a returning from already collides
2039 // with exception handling registers and so there is no issue.
2040 // (The exception handling path kills call result registers but
2041 // this is ok since the exception kills the result anyway).
2042
2043 if (is_at_poll_safepoint()) {
2044 // if the code we are returning to has deoptimized we must defer
2045 // the exception otherwise live registers get clobbered on the
2046 // exception path before deoptimization is able to retrieve them.
2047 //
2048 RegisterMap map(this, false);
2049 frame caller_fr = last_frame().sender(&map);
2050 assert(caller_fr.is_compiled_frame(), "what?");
2051 if (caller_fr.is_deoptimized_frame()) {
2052 if (TraceExceptions) {
2053 ResourceMark rm;
2054 tty->print_cr("deferred async exception at compiled safepoint");
2055 }
2056 return;
2057 }
2058 }
2059 }
2060
2061 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2062 if (condition == _no_async_condition) {
2063 // Conditions have changed since has_special_runtime_exit_condition()
2064 // was called:
2065 // - if we were here only because of an external suspend request,
2066 // then that was taken care of above (or cancelled) so we are done
2067 // - if we were here because of another async request, then it has
2068 // been cleared between the has_special_runtime_exit_condition()
2069 // and now so again we are done
2070 return;
2071 }
2072
2073 // Check for pending async. exception
2074 if (_pending_async_exception != NULL) {
2075 // Only overwrite an already pending exception, if it is not a threadDeath.
2076 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2077
2078 // We cannot call Exceptions::_throw(...) here because we cannot block
2079 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2080
2081 if (TraceExceptions) {
2082 ResourceMark rm;
2083 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2084 if (has_last_Java_frame()) {
2085 frame f = last_frame();
2086 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2087 }
2088 tty->print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2089 }
2090 _pending_async_exception = NULL;
2091 clear_has_async_exception();
2092 }
2093 }
2094
2095 if (check_unsafe_error &&
2096 condition == _async_unsafe_access_error && !has_pending_exception()) {
2097 condition = _no_async_condition; // done
2098 switch (thread_state()) {
2099 case _thread_in_vm: {
2100 JavaThread* THREAD = this;
2101 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2102 }
2103 case _thread_in_native: {
2104 ThreadInVMfromNative tiv(this);
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_Java: {
2109 ThreadInVMfromJava tiv(this);
2110 JavaThread* THREAD = this;
2111 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2112 }
2113 default:
2114 ShouldNotReachHere();
2115 }
2116 }
2117
2118 assert(condition == _no_async_condition || has_pending_exception() ||
2119 (!check_unsafe_error && condition == _async_unsafe_access_error),
2120 "must have handled the async condition, if no exception");
2121 }
2122
2123 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2124 //
2125 // Check for pending external suspend. Internal suspend requests do
2126 // not use handle_special_runtime_exit_condition().
2127 // If JNIEnv proxies are allowed, don't self-suspend if the target
2128 // thread is not the current thread. In older versions of jdbx, jdbx
2129 // threads could call into the VM with another thread's JNIEnv so we
2130 // can be here operating on behalf of a suspended thread (4432884).
2131 bool do_self_suspend = is_external_suspend_with_lock();
2132 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2133 //
2134 // Because thread is external suspended the safepoint code will count
2135 // thread as at a safepoint. This can be odd because we can be here
2136 // as _thread_in_Java which would normally transition to _thread_blocked
2137 // at a safepoint. We would like to mark the thread as _thread_blocked
2138 // before calling java_suspend_self like all other callers of it but
2139 // we must then observe proper safepoint protocol. (We can't leave
2140 // _thread_blocked with a safepoint in progress). However we can be
2141 // here as _thread_in_native_trans so we can't use a normal transition
2142 // constructor/destructor pair because they assert on that type of
2143 // transition. We could do something like:
2144 //
2145 // JavaThreadState state = thread_state();
2146 // set_thread_state(_thread_in_vm);
2147 // {
2148 // ThreadBlockInVM tbivm(this);
2149 // java_suspend_self()
2150 // }
2151 // set_thread_state(_thread_in_vm_trans);
2152 // if (safepoint) block;
2153 // set_thread_state(state);
2154 //
2155 // but that is pretty messy. Instead we just go with the way the
2156 // code has worked before and note that this is the only path to
2157 // java_suspend_self that doesn't put the thread in _thread_blocked
2158 // mode.
2159
2160 frame_anchor()->make_walkable(this);
2161 java_suspend_self();
2162
2163 // We might be here for reasons in addition to the self-suspend request
2164 // so check for other async requests.
2165 }
2166
2167 if (check_asyncs) {
2168 check_and_handle_async_exceptions();
2169 }
2170 }
2171
2172 void JavaThread::send_thread_stop(oop java_throwable) {
2173 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2174 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2175 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2176
2177 // Do not throw asynchronous exceptions against the compiler thread
2178 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2179 if (!can_call_java()) return;
2180
2181 {
2182 // Actually throw the Throwable against the target Thread - however
2183 // only if there is no thread death exception installed already.
2184 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2185 // If the topmost frame is a runtime stub, then we are calling into
2186 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2187 // must deoptimize the caller before continuing, as the compiled exception handler table
2188 // may not be valid
2189 if (has_last_Java_frame()) {
2190 frame f = last_frame();
2191 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2192 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2193 RegisterMap reg_map(this, UseBiasedLocking);
2194 frame compiled_frame = f.sender(®_map);
2195 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2196 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2197 }
2198 }
2199 }
2200
2201 // Set async. pending exception in thread.
2202 set_pending_async_exception(java_throwable);
2203
2204 if (TraceExceptions) {
2205 ResourceMark rm;
2206 tty->print_cr("Pending Async. exception installed of type: %s", _pending_async_exception->klass()->external_name());
2207 }
2208 // for AbortVMOnException flag
2209 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2210 }
2211 }
2212
2213
2214 // Interrupt thread so it will wake up from a potential wait()
2215 Thread::interrupt(this);
2216 }
2217
2218 // External suspension mechanism.
2219 //
2220 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2221 // to any VM_locks and it is at a transition
2222 // Self-suspension will happen on the transition out of the vm.
2223 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2224 //
2225 // Guarantees on return:
2226 // + Target thread will not execute any new bytecode (that's why we need to
2227 // force a safepoint)
2228 // + Target thread will not enter any new monitors
2229 //
2230 void JavaThread::java_suspend() {
2231 { MutexLocker mu(Threads_lock);
2232 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2233 return;
2234 }
2235 }
2236
2237 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2238 if (!is_external_suspend()) {
2239 // a racing resume has cancelled us; bail out now
2240 return;
2241 }
2242
2243 // suspend is done
2244 uint32_t debug_bits = 0;
2245 // Warning: is_ext_suspend_completed() may temporarily drop the
2246 // SR_lock to allow the thread to reach a stable thread state if
2247 // it is currently in a transient thread state.
2248 if (is_ext_suspend_completed(false /* !called_by_wait */,
2249 SuspendRetryDelay, &debug_bits)) {
2250 return;
2251 }
2252 }
2253
2254 VM_ForceSafepoint vm_suspend;
2255 VMThread::execute(&vm_suspend);
2256 }
2257
2258 // Part II of external suspension.
2259 // A JavaThread self suspends when it detects a pending external suspend
2260 // request. This is usually on transitions. It is also done in places
2261 // where continuing to the next transition would surprise the caller,
2262 // e.g., monitor entry.
2263 //
2264 // Returns the number of times that the thread self-suspended.
2265 //
2266 // Note: DO NOT call java_suspend_self() when you just want to block current
2267 // thread. java_suspend_self() is the second stage of cooperative
2268 // suspension for external suspend requests and should only be used
2269 // to complete an external suspend request.
2270 //
2271 int JavaThread::java_suspend_self() {
2272 int ret = 0;
2273
2274 // we are in the process of exiting so don't suspend
2275 if (is_exiting()) {
2276 clear_external_suspend();
2277 return ret;
2278 }
2279
2280 assert(_anchor.walkable() ||
2281 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2282 "must have walkable stack");
2283
2284 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2285
2286 assert(!this->is_ext_suspended(),
2287 "a thread trying to self-suspend should not already be suspended");
2288
2289 if (this->is_suspend_equivalent()) {
2290 // If we are self-suspending as a result of the lifting of a
2291 // suspend equivalent condition, then the suspend_equivalent
2292 // flag is not cleared until we set the ext_suspended flag so
2293 // that wait_for_ext_suspend_completion() returns consistent
2294 // results.
2295 this->clear_suspend_equivalent();
2296 }
2297
2298 // A racing resume may have cancelled us before we grabbed SR_lock
2299 // above. Or another external suspend request could be waiting for us
2300 // by the time we return from SR_lock()->wait(). The thread
2301 // that requested the suspension may already be trying to walk our
2302 // stack and if we return now, we can change the stack out from under
2303 // it. This would be a "bad thing (TM)" and cause the stack walker
2304 // to crash. We stay self-suspended until there are no more pending
2305 // external suspend requests.
2306 while (is_external_suspend()) {
2307 ret++;
2308 this->set_ext_suspended();
2309
2310 // _ext_suspended flag is cleared by java_resume()
2311 while (is_ext_suspended()) {
2312 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2313 }
2314 }
2315
2316 return ret;
2317 }
2318
2319 #ifdef ASSERT
2320 // verify the JavaThread has not yet been published in the Threads::list, and
2321 // hence doesn't need protection from concurrent access at this stage
2322 void JavaThread::verify_not_published() {
2323 if (!Threads_lock->owned_by_self()) {
2324 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2325 assert(!Threads::includes(this),
2326 "java thread shouldn't have been published yet!");
2327 } else {
2328 assert(!Threads::includes(this),
2329 "java thread shouldn't have been published yet!");
2330 }
2331 }
2332 #endif
2333
2334 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2335 // progress or when _suspend_flags is non-zero.
2336 // Current thread needs to self-suspend if there is a suspend request and/or
2337 // block if a safepoint is in progress.
2338 // Async exception ISN'T checked.
2339 // Note only the ThreadInVMfromNative transition can call this function
2340 // directly and when thread state is _thread_in_native_trans
2341 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2342 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2343
2344 JavaThread *curJT = JavaThread::current();
2345 bool do_self_suspend = thread->is_external_suspend();
2346
2347 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2348
2349 // If JNIEnv proxies are allowed, don't self-suspend if the target
2350 // thread is not the current thread. In older versions of jdbx, jdbx
2351 // threads could call into the VM with another thread's JNIEnv so we
2352 // can be here operating on behalf of a suspended thread (4432884).
2353 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2354 JavaThreadState state = thread->thread_state();
2355
2356 // We mark this thread_blocked state as a suspend-equivalent so
2357 // that a caller to is_ext_suspend_completed() won't be confused.
2358 // The suspend-equivalent state is cleared by java_suspend_self().
2359 thread->set_suspend_equivalent();
2360
2361 // If the safepoint code sees the _thread_in_native_trans state, it will
2362 // wait until the thread changes to other thread state. There is no
2363 // guarantee on how soon we can obtain the SR_lock and complete the
2364 // self-suspend request. It would be a bad idea to let safepoint wait for
2365 // too long. Temporarily change the state to _thread_blocked to
2366 // let the VM thread know that this thread is ready for GC. The problem
2367 // of changing thread state is that safepoint could happen just after
2368 // java_suspend_self() returns after being resumed, and VM thread will
2369 // see the _thread_blocked state. We must check for safepoint
2370 // after restoring the state and make sure we won't leave while a safepoint
2371 // is in progress.
2372 thread->set_thread_state(_thread_blocked);
2373 thread->java_suspend_self();
2374 thread->set_thread_state(state);
2375 // Make sure new state is seen by VM thread
2376 if (os::is_MP()) {
2377 if (UseMembar) {
2378 // Force a fence between the write above and read below
2379 OrderAccess::fence();
2380 } else {
2381 // Must use this rather than serialization page in particular on Windows
2382 InterfaceSupport::serialize_memory(thread);
2383 }
2384 }
2385 }
2386
2387 if (SafepointSynchronize::do_call_back()) {
2388 // If we are safepointing, then block the caller which may not be
2389 // the same as the target thread (see above).
2390 SafepointSynchronize::block(curJT);
2391 }
2392
2393 if (thread->is_deopt_suspend()) {
2394 thread->clear_deopt_suspend();
2395 RegisterMap map(thread, false);
2396 frame f = thread->last_frame();
2397 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2398 f = f.sender(&map);
2399 }
2400 if (f.id() == thread->must_deopt_id()) {
2401 thread->clear_must_deopt_id();
2402 f.deoptimize(thread);
2403 } else {
2404 fatal("missed deoptimization!");
2405 }
2406 }
2407 }
2408
2409 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2410 // progress or when _suspend_flags is non-zero.
2411 // Current thread needs to self-suspend if there is a suspend request and/or
2412 // block if a safepoint is in progress.
2413 // Also check for pending async exception (not including unsafe access error).
2414 // Note only the native==>VM/Java barriers can call this function and when
2415 // thread state is _thread_in_native_trans.
2416 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2417 check_safepoint_and_suspend_for_native_trans(thread);
2418
2419 if (thread->has_async_exception()) {
2420 // We are in _thread_in_native_trans state, don't handle unsafe
2421 // access error since that may block.
2422 thread->check_and_handle_async_exceptions(false);
2423 }
2424 }
2425
2426 // This is a variant of the normal
2427 // check_special_condition_for_native_trans with slightly different
2428 // semantics for use by critical native wrappers. It does all the
2429 // normal checks but also performs the transition back into
2430 // thread_in_Java state. This is required so that critical natives
2431 // can potentially block and perform a GC if they are the last thread
2432 // exiting the GC_locker.
2433 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2434 check_special_condition_for_native_trans(thread);
2435
2436 // Finish the transition
2437 thread->set_thread_state(_thread_in_Java);
2438
2439 if (thread->do_critical_native_unlock()) {
2440 ThreadInVMfromJavaNoAsyncException tiv(thread);
2441 GC_locker::unlock_critical(thread);
2442 thread->clear_critical_native_unlock();
2443 }
2444 }
2445
2446 // We need to guarantee the Threads_lock here, since resumes are not
2447 // allowed during safepoint synchronization
2448 // Can only resume from an external suspension
2449 void JavaThread::java_resume() {
2450 assert_locked_or_safepoint(Threads_lock);
2451
2452 // Sanity check: thread is gone, has started exiting or the thread
2453 // was not externally suspended.
2454 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2455 return;
2456 }
2457
2458 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2459
2460 clear_external_suspend();
2461
2462 if (is_ext_suspended()) {
2463 clear_ext_suspended();
2464 SR_lock()->notify_all();
2465 }
2466 }
2467
2468 void JavaThread::create_stack_guard_pages() {
2469 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2470 address low_addr = stack_base() - stack_size();
2471 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2472
2473 int allocate = os::allocate_stack_guard_pages();
2474 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2475
2476 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2477 warning("Attempt to allocate stack guard pages failed.");
2478 return;
2479 }
2480
2481 if (os::guard_memory((char *) low_addr, len)) {
2482 _stack_guard_state = stack_guard_enabled;
2483 } else {
2484 warning("Attempt to protect stack guard pages failed.");
2485 if (os::uncommit_memory((char *) low_addr, len)) {
2486 warning("Attempt to deallocate stack guard pages failed.");
2487 }
2488 }
2489 }
2490
2491 void JavaThread::remove_stack_guard_pages() {
2492 assert(Thread::current() == this, "from different thread");
2493 if (_stack_guard_state == stack_guard_unused) return;
2494 address low_addr = stack_base() - stack_size();
2495 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2496
2497 if (os::allocate_stack_guard_pages()) {
2498 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2499 _stack_guard_state = stack_guard_unused;
2500 } else {
2501 warning("Attempt to deallocate stack guard pages failed.");
2502 }
2503 } else {
2504 if (_stack_guard_state == stack_guard_unused) return;
2505 if (os::unguard_memory((char *) low_addr, len)) {
2506 _stack_guard_state = stack_guard_unused;
2507 } else {
2508 warning("Attempt to unprotect stack guard pages failed.");
2509 }
2510 }
2511 }
2512
2513 void JavaThread::enable_stack_yellow_zone() {
2514 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2515 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2516
2517 // The base notation is from the stacks point of view, growing downward.
2518 // We need to adjust it to work correctly with guard_memory()
2519 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2520
2521 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2522 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2523
2524 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2525 _stack_guard_state = stack_guard_enabled;
2526 } else {
2527 warning("Attempt to guard stack yellow zone failed.");
2528 }
2529 enable_register_stack_guard();
2530 }
2531
2532 void JavaThread::disable_stack_yellow_zone() {
2533 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2534 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2535
2536 // Simply return if called for a thread that does not use guard pages.
2537 if (_stack_guard_state == stack_guard_unused) return;
2538
2539 // The base notation is from the stacks point of view, growing downward.
2540 // We need to adjust it to work correctly with guard_memory()
2541 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2542
2543 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2544 _stack_guard_state = stack_guard_yellow_disabled;
2545 } else {
2546 warning("Attempt to unguard stack yellow zone failed.");
2547 }
2548 disable_register_stack_guard();
2549 }
2550
2551 void JavaThread::enable_stack_red_zone() {
2552 // The base notation is from the stacks point of view, growing downward.
2553 // We need to adjust it to work correctly with guard_memory()
2554 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2555 address base = stack_red_zone_base() - stack_red_zone_size();
2556
2557 guarantee(base < stack_base(), "Error calculating stack red zone");
2558 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2559
2560 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2561 warning("Attempt to guard stack red zone failed.");
2562 }
2563 }
2564
2565 void JavaThread::disable_stack_red_zone() {
2566 // The base notation is from the stacks point of view, growing downward.
2567 // We need to adjust it to work correctly with guard_memory()
2568 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2569 address base = stack_red_zone_base() - stack_red_zone_size();
2570 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2571 warning("Attempt to unguard stack red zone failed.");
2572 }
2573 }
2574
2575 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2576 // ignore is there is no stack
2577 if (!has_last_Java_frame()) return;
2578 // traverse the stack frames. Starts from top frame.
2579 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2580 frame* fr = fst.current();
2581 f(fr, fst.register_map());
2582 }
2583 }
2584
2585
2586 #ifndef PRODUCT
2587 // Deoptimization
2588 // Function for testing deoptimization
2589 void JavaThread::deoptimize() {
2590 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2591 StackFrameStream fst(this, UseBiasedLocking);
2592 bool deopt = false; // Dump stack only if a deopt actually happens.
2593 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2594 // Iterate over all frames in the thread and deoptimize
2595 for (; !fst.is_done(); fst.next()) {
2596 if (fst.current()->can_be_deoptimized()) {
2597
2598 if (only_at) {
2599 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2600 // consists of comma or carriage return separated numbers so
2601 // search for the current bci in that string.
2602 address pc = fst.current()->pc();
2603 nmethod* nm = (nmethod*) fst.current()->cb();
2604 ScopeDesc* sd = nm->scope_desc_at(pc);
2605 char buffer[8];
2606 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2607 size_t len = strlen(buffer);
2608 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2609 while (found != NULL) {
2610 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2611 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2612 // Check that the bci found is bracketed by terminators.
2613 break;
2614 }
2615 found = strstr(found + 1, buffer);
2616 }
2617 if (!found) {
2618 continue;
2619 }
2620 }
2621
2622 if (DebugDeoptimization && !deopt) {
2623 deopt = true; // One-time only print before deopt
2624 tty->print_cr("[BEFORE Deoptimization]");
2625 trace_frames();
2626 trace_stack();
2627 }
2628 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2629 }
2630 }
2631
2632 if (DebugDeoptimization && deopt) {
2633 tty->print_cr("[AFTER Deoptimization]");
2634 trace_frames();
2635 }
2636 }
2637
2638
2639 // Make zombies
2640 void JavaThread::make_zombies() {
2641 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2642 if (fst.current()->can_be_deoptimized()) {
2643 // it is a Java nmethod
2644 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2645 nm->make_not_entrant();
2646 }
2647 }
2648 }
2649 #endif // PRODUCT
2650
2651
2652 void JavaThread::deoptimized_wrt_marked_nmethods() {
2653 if (!has_last_Java_frame()) return;
2654 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2655 StackFrameStream fst(this, UseBiasedLocking);
2656 for (; !fst.is_done(); fst.next()) {
2657 if (fst.current()->should_be_deoptimized()) {
2658 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2659 }
2660 }
2661 }
2662
2663
2664 // If the caller is a NamedThread, then remember, in the current scope,
2665 // the given JavaThread in its _processed_thread field.
2666 class RememberProcessedThread: public StackObj {
2667 NamedThread* _cur_thr;
2668 public:
2669 RememberProcessedThread(JavaThread* jthr) {
2670 Thread* thread = Thread::current();
2671 if (thread->is_Named_thread()) {
2672 _cur_thr = (NamedThread *)thread;
2673 _cur_thr->set_processed_thread(jthr);
2674 } else {
2675 _cur_thr = NULL;
2676 }
2677 }
2678
2679 ~RememberProcessedThread() {
2680 if (_cur_thr) {
2681 _cur_thr->set_processed_thread(NULL);
2682 }
2683 }
2684 };
2685
2686 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2687 // Verify that the deferred card marks have been flushed.
2688 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2689
2690 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2691 // since there may be more than one thread using each ThreadProfiler.
2692
2693 // Traverse the GCHandles
2694 Thread::oops_do(f, cld_f, cf);
2695
2696 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2697
2698 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2699 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2700
2701 if (has_last_Java_frame()) {
2702 // Record JavaThread to GC thread
2703 RememberProcessedThread rpt(this);
2704
2705 // Traverse the privileged stack
2706 if (_privileged_stack_top != NULL) {
2707 _privileged_stack_top->oops_do(f);
2708 }
2709
2710 // traverse the registered growable array
2711 if (_array_for_gc != NULL) {
2712 for (int index = 0; index < _array_for_gc->length(); index++) {
2713 f->do_oop(_array_for_gc->adr_at(index));
2714 }
2715 }
2716
2717 // Traverse the monitor chunks
2718 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2719 chunk->oops_do(f);
2720 }
2721
2722 // Traverse the execution stack
2723 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2724 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2725 }
2726 }
2727
2728 // callee_target is never live across a gc point so NULL it here should
2729 // it still contain a methdOop.
2730
2731 set_callee_target(NULL);
2732
2733 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2734 // If we have deferred set_locals there might be oops waiting to be
2735 // written
2736 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2737 if (list != NULL) {
2738 for (int i = 0; i < list->length(); i++) {
2739 list->at(i)->oops_do(f);
2740 }
2741 }
2742
2743 // Traverse instance variables at the end since the GC may be moving things
2744 // around using this function
2745 f->do_oop((oop*) &_threadObj);
2746 f->do_oop((oop*) &_vm_result);
2747 f->do_oop((oop*) &_exception_oop);
2748 f->do_oop((oop*) &_pending_async_exception);
2749
2750 if (jvmti_thread_state() != NULL) {
2751 jvmti_thread_state()->oops_do(f);
2752 }
2753 }
2754
2755 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2756 Thread::nmethods_do(cf); // (super method is a no-op)
2757
2758 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2759 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2760
2761 if (has_last_Java_frame()) {
2762 // Traverse the execution stack
2763 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2764 fst.current()->nmethods_do(cf);
2765 }
2766 }
2767 }
2768
2769 void JavaThread::metadata_do(void f(Metadata*)) {
2770 if (has_last_Java_frame()) {
2771 // Traverse the execution stack to call f() on the methods in the stack
2772 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2773 fst.current()->metadata_do(f);
2774 }
2775 } else if (is_Compiler_thread()) {
2776 // need to walk ciMetadata in current compile tasks to keep alive.
2777 CompilerThread* ct = (CompilerThread*)this;
2778 if (ct->env() != NULL) {
2779 ct->env()->metadata_do(f);
2780 }
2781 if (ct->task() != NULL) {
2782 ct->task()->metadata_do(f);
2783 }
2784 }
2785 }
2786
2787 // Printing
2788 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2789 switch (_thread_state) {
2790 case _thread_uninitialized: return "_thread_uninitialized";
2791 case _thread_new: return "_thread_new";
2792 case _thread_new_trans: return "_thread_new_trans";
2793 case _thread_in_native: return "_thread_in_native";
2794 case _thread_in_native_trans: return "_thread_in_native_trans";
2795 case _thread_in_vm: return "_thread_in_vm";
2796 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2797 case _thread_in_Java: return "_thread_in_Java";
2798 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2799 case _thread_blocked: return "_thread_blocked";
2800 case _thread_blocked_trans: return "_thread_blocked_trans";
2801 default: return "unknown thread state";
2802 }
2803 }
2804
2805 #ifndef PRODUCT
2806 void JavaThread::print_thread_state_on(outputStream *st) const {
2807 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2808 };
2809 void JavaThread::print_thread_state() const {
2810 print_thread_state_on(tty);
2811 }
2812 #endif // PRODUCT
2813
2814 // Called by Threads::print() for VM_PrintThreads operation
2815 void JavaThread::print_on(outputStream *st) const {
2816 st->print("\"%s\" ", get_thread_name());
2817 oop thread_oop = threadObj();
2818 if (thread_oop != NULL) {
2819 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2820 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2821 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2822 }
2823 Thread::print_on(st);
2824 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2825 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2826 if (thread_oop != NULL) {
2827 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2828 }
2829 #ifndef PRODUCT
2830 print_thread_state_on(st);
2831 _safepoint_state->print_on(st);
2832 #endif // PRODUCT
2833 }
2834
2835 // Called by fatal error handler. The difference between this and
2836 // JavaThread::print() is that we can't grab lock or allocate memory.
2837 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2838 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2839 oop thread_obj = threadObj();
2840 if (thread_obj != NULL) {
2841 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2842 }
2843 st->print(" [");
2844 st->print("%s", _get_thread_state_name(_thread_state));
2845 if (osthread()) {
2846 st->print(", id=%d", osthread()->thread_id());
2847 }
2848 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2849 p2i(_stack_base - _stack_size), p2i(_stack_base));
2850 st->print("]");
2851 return;
2852 }
2853
2854 // Verification
2855
2856 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2857
2858 void JavaThread::verify() {
2859 // Verify oops in the thread.
2860 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2861
2862 // Verify the stack frames.
2863 frames_do(frame_verify);
2864 }
2865
2866 // CR 6300358 (sub-CR 2137150)
2867 // Most callers of this method assume that it can't return NULL but a
2868 // thread may not have a name whilst it is in the process of attaching to
2869 // the VM - see CR 6412693, and there are places where a JavaThread can be
2870 // seen prior to having it's threadObj set (eg JNI attaching threads and
2871 // if vm exit occurs during initialization). These cases can all be accounted
2872 // for such that this method never returns NULL.
2873 const char* JavaThread::get_thread_name() const {
2874 #ifdef ASSERT
2875 // early safepoints can hit while current thread does not yet have TLS
2876 if (!SafepointSynchronize::is_at_safepoint()) {
2877 Thread *cur = Thread::current();
2878 if (!(cur->is_Java_thread() && cur == this)) {
2879 // Current JavaThreads are allowed to get their own name without
2880 // the Threads_lock.
2881 assert_locked_or_safepoint(Threads_lock);
2882 }
2883 }
2884 #endif // ASSERT
2885 return get_thread_name_string();
2886 }
2887
2888 // Returns a non-NULL representation of this thread's name, or a suitable
2889 // descriptive string if there is no set name
2890 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2891 const char* name_str;
2892 oop thread_obj = threadObj();
2893 if (thread_obj != NULL) {
2894 oop name = java_lang_Thread::name(thread_obj);
2895 if (name != NULL) {
2896 if (buf == NULL) {
2897 name_str = java_lang_String::as_utf8_string(name);
2898 } else {
2899 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2900 }
2901 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2902 name_str = "<no-name - thread is attaching>";
2903 } else {
2904 name_str = Thread::name();
2905 }
2906 } else {
2907 name_str = Thread::name();
2908 }
2909 assert(name_str != NULL, "unexpected NULL thread name");
2910 return name_str;
2911 }
2912
2913
2914 const char* JavaThread::get_threadgroup_name() const {
2915 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2916 oop thread_obj = threadObj();
2917 if (thread_obj != NULL) {
2918 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2919 if (thread_group != NULL) {
2920 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2921 // ThreadGroup.name can be null
2922 if (name != NULL) {
2923 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2924 return str;
2925 }
2926 }
2927 }
2928 return NULL;
2929 }
2930
2931 const char* JavaThread::get_parent_name() const {
2932 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2933 oop thread_obj = threadObj();
2934 if (thread_obj != NULL) {
2935 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2936 if (thread_group != NULL) {
2937 oop parent = java_lang_ThreadGroup::parent(thread_group);
2938 if (parent != NULL) {
2939 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2940 // ThreadGroup.name can be null
2941 if (name != NULL) {
2942 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2943 return str;
2944 }
2945 }
2946 }
2947 }
2948 return NULL;
2949 }
2950
2951 ThreadPriority JavaThread::java_priority() const {
2952 oop thr_oop = threadObj();
2953 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2954 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2955 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2956 return priority;
2957 }
2958
2959 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2960
2961 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2962 // Link Java Thread object <-> C++ Thread
2963
2964 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2965 // and put it into a new Handle. The Handle "thread_oop" can then
2966 // be used to pass the C++ thread object to other methods.
2967
2968 // Set the Java level thread object (jthread) field of the
2969 // new thread (a JavaThread *) to C++ thread object using the
2970 // "thread_oop" handle.
2971
2972 // Set the thread field (a JavaThread *) of the
2973 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2974
2975 Handle thread_oop(Thread::current(),
2976 JNIHandles::resolve_non_null(jni_thread));
2977 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2978 "must be initialized");
2979 set_threadObj(thread_oop());
2980 java_lang_Thread::set_thread(thread_oop(), this);
2981
2982 if (prio == NoPriority) {
2983 prio = java_lang_Thread::priority(thread_oop());
2984 assert(prio != NoPriority, "A valid priority should be present");
2985 }
2986
2987 // Push the Java priority down to the native thread; needs Threads_lock
2988 Thread::set_priority(this, prio);
2989
2990 prepare_ext();
2991
2992 // Add the new thread to the Threads list and set it in motion.
2993 // We must have threads lock in order to call Threads::add.
2994 // It is crucial that we do not block before the thread is
2995 // added to the Threads list for if a GC happens, then the java_thread oop
2996 // will not be visited by GC.
2997 Threads::add(this);
2998 }
2999
3000 oop JavaThread::current_park_blocker() {
3001 // Support for JSR-166 locks
3002 oop thread_oop = threadObj();
3003 if (thread_oop != NULL &&
3004 JDK_Version::current().supports_thread_park_blocker()) {
3005 return java_lang_Thread::park_blocker(thread_oop);
3006 }
3007 return NULL;
3008 }
3009
3010
3011 void JavaThread::print_stack_on(outputStream* st) {
3012 if (!has_last_Java_frame()) return;
3013 ResourceMark rm;
3014 HandleMark hm;
3015
3016 RegisterMap reg_map(this);
3017 vframe* start_vf = last_java_vframe(®_map);
3018 int count = 0;
3019 for (vframe* f = start_vf; f; f = f->sender()) {
3020 if (f->is_java_frame()) {
3021 javaVFrame* jvf = javaVFrame::cast(f);
3022 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3023
3024 // Print out lock information
3025 if (JavaMonitorsInStackTrace) {
3026 jvf->print_lock_info_on(st, count);
3027 }
3028 } else {
3029 // Ignore non-Java frames
3030 }
3031
3032 // Bail-out case for too deep stacks
3033 count++;
3034 if (MaxJavaStackTraceDepth == count) return;
3035 }
3036 }
3037
3038
3039 // JVMTI PopFrame support
3040 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3041 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3042 if (in_bytes(size_in_bytes) != 0) {
3043 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3044 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3045 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3046 }
3047 }
3048
3049 void* JavaThread::popframe_preserved_args() {
3050 return _popframe_preserved_args;
3051 }
3052
3053 ByteSize JavaThread::popframe_preserved_args_size() {
3054 return in_ByteSize(_popframe_preserved_args_size);
3055 }
3056
3057 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3058 int sz = in_bytes(popframe_preserved_args_size());
3059 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3060 return in_WordSize(sz / wordSize);
3061 }
3062
3063 void JavaThread::popframe_free_preserved_args() {
3064 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3065 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3066 _popframe_preserved_args = NULL;
3067 _popframe_preserved_args_size = 0;
3068 }
3069
3070 #ifndef PRODUCT
3071
3072 void JavaThread::trace_frames() {
3073 tty->print_cr("[Describe stack]");
3074 int frame_no = 1;
3075 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3076 tty->print(" %d. ", frame_no++);
3077 fst.current()->print_value_on(tty, this);
3078 tty->cr();
3079 }
3080 }
3081
3082 class PrintAndVerifyOopClosure: public OopClosure {
3083 protected:
3084 template <class T> inline void do_oop_work(T* p) {
3085 oop obj = oopDesc::load_decode_heap_oop(p);
3086 if (obj == NULL) return;
3087 tty->print(INTPTR_FORMAT ": ", p2i(p));
3088 if (obj->is_oop_or_null()) {
3089 if (obj->is_objArray()) {
3090 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3091 } else {
3092 obj->print();
3093 }
3094 } else {
3095 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3096 }
3097 tty->cr();
3098 }
3099 public:
3100 virtual void do_oop(oop* p) { do_oop_work(p); }
3101 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3102 };
3103
3104
3105 static void oops_print(frame* f, const RegisterMap *map) {
3106 PrintAndVerifyOopClosure print;
3107 f->print_value();
3108 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3109 }
3110
3111 // Print our all the locations that contain oops and whether they are
3112 // valid or not. This useful when trying to find the oldest frame
3113 // where an oop has gone bad since the frame walk is from youngest to
3114 // oldest.
3115 void JavaThread::trace_oops() {
3116 tty->print_cr("[Trace oops]");
3117 frames_do(oops_print);
3118 }
3119
3120
3121 #ifdef ASSERT
3122 // Print or validate the layout of stack frames
3123 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3124 ResourceMark rm;
3125 PRESERVE_EXCEPTION_MARK;
3126 FrameValues values;
3127 int frame_no = 0;
3128 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3129 fst.current()->describe(values, ++frame_no);
3130 if (depth == frame_no) break;
3131 }
3132 if (validate_only) {
3133 values.validate();
3134 } else {
3135 tty->print_cr("[Describe stack layout]");
3136 values.print(this);
3137 }
3138 }
3139 #endif
3140
3141 void JavaThread::trace_stack_from(vframe* start_vf) {
3142 ResourceMark rm;
3143 int vframe_no = 1;
3144 for (vframe* f = start_vf; f; f = f->sender()) {
3145 if (f->is_java_frame()) {
3146 javaVFrame::cast(f)->print_activation(vframe_no++);
3147 } else {
3148 f->print();
3149 }
3150 if (vframe_no > StackPrintLimit) {
3151 tty->print_cr("...<more frames>...");
3152 return;
3153 }
3154 }
3155 }
3156
3157
3158 void JavaThread::trace_stack() {
3159 if (!has_last_Java_frame()) return;
3160 ResourceMark rm;
3161 HandleMark hm;
3162 RegisterMap reg_map(this);
3163 trace_stack_from(last_java_vframe(®_map));
3164 }
3165
3166
3167 #endif // PRODUCT
3168
3169
3170 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3171 assert(reg_map != NULL, "a map must be given");
3172 frame f = last_frame();
3173 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3174 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3175 }
3176 return NULL;
3177 }
3178
3179
3180 Klass* JavaThread::security_get_caller_class(int depth) {
3181 vframeStream vfst(this);
3182 vfst.security_get_caller_frame(depth);
3183 if (!vfst.at_end()) {
3184 return vfst.method()->method_holder();
3185 }
3186 return NULL;
3187 }
3188
3189 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3190 assert(thread->is_Compiler_thread(), "must be compiler thread");
3191 CompileBroker::compiler_thread_loop();
3192 }
3193
3194 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3195 NMethodSweeper::sweeper_loop();
3196 }
3197
3198 // Create a CompilerThread
3199 CompilerThread::CompilerThread(CompileQueue* queue,
3200 CompilerCounters* counters)
3201 : JavaThread(&compiler_thread_entry) {
3202 _env = NULL;
3203 _log = NULL;
3204 _task = NULL;
3205 _queue = queue;
3206 _counters = counters;
3207 _buffer_blob = NULL;
3208 _compiler = NULL;
3209
3210 #ifndef PRODUCT
3211 _ideal_graph_printer = NULL;
3212 #endif
3213 }
3214
3215 bool CompilerThread::can_call_java() const {
3216 return _compiler != NULL && _compiler->is_jvmci();
3217 }
3218
3219 // Create sweeper thread
3220 CodeCacheSweeperThread::CodeCacheSweeperThread()
3221 : JavaThread(&sweeper_thread_entry) {
3222 _scanned_nmethod = NULL;
3223 }
3224 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3225 JavaThread::oops_do(f, cld_f, cf);
3226 if (_scanned_nmethod != NULL && cf != NULL) {
3227 // Safepoints can occur when the sweeper is scanning an nmethod so
3228 // process it here to make sure it isn't unloaded in the middle of
3229 // a scan.
3230 cf->do_code_blob(_scanned_nmethod);
3231 }
3232 }
3233
3234
3235 // ======= Threads ========
3236
3237 // The Threads class links together all active threads, and provides
3238 // operations over all threads. It is protected by its own Mutex
3239 // lock, which is also used in other contexts to protect thread
3240 // operations from having the thread being operated on from exiting
3241 // and going away unexpectedly (e.g., safepoint synchronization)
3242
3243 JavaThread* Threads::_thread_list = NULL;
3244 int Threads::_number_of_threads = 0;
3245 int Threads::_number_of_non_daemon_threads = 0;
3246 int Threads::_return_code = 0;
3247 int Threads::_thread_claim_parity = 0;
3248 size_t JavaThread::_stack_size_at_create = 0;
3249 #ifdef ASSERT
3250 bool Threads::_vm_complete = false;
3251 #endif
3252
3253 // All JavaThreads
3254 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3255
3256 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3257 void Threads::threads_do(ThreadClosure* tc) {
3258 assert_locked_or_safepoint(Threads_lock);
3259 // ALL_JAVA_THREADS iterates through all JavaThreads
3260 ALL_JAVA_THREADS(p) {
3261 tc->do_thread(p);
3262 }
3263 // Someday we could have a table or list of all non-JavaThreads.
3264 // For now, just manually iterate through them.
3265 tc->do_thread(VMThread::vm_thread());
3266 Universe::heap()->gc_threads_do(tc);
3267 WatcherThread *wt = WatcherThread::watcher_thread();
3268 // Strictly speaking, the following NULL check isn't sufficient to make sure
3269 // the data for WatcherThread is still valid upon being examined. However,
3270 // considering that WatchThread terminates when the VM is on the way to
3271 // exit at safepoint, the chance of the above is extremely small. The right
3272 // way to prevent termination of WatcherThread would be to acquire
3273 // Terminator_lock, but we can't do that without violating the lock rank
3274 // checking in some cases.
3275 if (wt != NULL) {
3276 tc->do_thread(wt);
3277 }
3278
3279 // If CompilerThreads ever become non-JavaThreads, add them here
3280 }
3281
3282 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3283 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3284
3285 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3286 create_vm_init_libraries();
3287 }
3288
3289 initialize_class(vmSymbols::java_lang_String(), CHECK);
3290
3291 // Initialize java_lang.System (needed before creating the thread)
3292 initialize_class(vmSymbols::java_lang_System(), CHECK);
3293 // The VM creates & returns objects of this class. Make sure it's initialized.
3294 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3295 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3296 Handle thread_group = create_initial_thread_group(CHECK);
3297 Universe::set_main_thread_group(thread_group());
3298 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3299 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3300 main_thread->set_threadObj(thread_object);
3301 // Set thread status to running since main thread has
3302 // been started and running.
3303 java_lang_Thread::set_thread_status(thread_object,
3304 java_lang_Thread::RUNNABLE);
3305
3306 // The VM preresolves methods to these classes. Make sure that they get initialized
3307 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3308 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3309 call_initializeSystemClass(CHECK);
3310
3311 // get the Java runtime name after java.lang.System is initialized
3312 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3313 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3314
3315 // an instance of OutOfMemory exception has been allocated earlier
3316 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3317 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3318 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3319 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3320 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3321 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3322 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3323 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3324 }
3325
3326 void Threads::initialize_jsr292_core_classes(TRAPS) {
3327 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3328 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3329 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3330 }
3331
3332 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3333 extern void JDK_Version_init();
3334
3335 // Preinitialize version info.
3336 VM_Version::early_initialize();
3337
3338 // Check version
3339 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3340
3341 // Initialize the output stream module
3342 ostream_init();
3343
3344 // Process java launcher properties.
3345 Arguments::process_sun_java_launcher_properties(args);
3346
3347 // Initialize the os module before using TLS
3348 os::init();
3349
3350 // Record VM creation timing statistics
3351 TraceVmCreationTime create_vm_timer;
3352 create_vm_timer.start();
3353
3354 // Initialize system properties.
3355 Arguments::init_system_properties();
3356
3357 // So that JDK version can be used as a discriminator when parsing arguments
3358 JDK_Version_init();
3359
3360 // Update/Initialize System properties after JDK version number is known
3361 Arguments::init_version_specific_system_properties();
3362
3363 // Make sure to initialize log configuration *before* parsing arguments
3364 LogConfiguration::initialize(create_vm_timer.begin_time());
3365
3366 // Parse arguments
3367 jint parse_result = Arguments::parse(args);
3368 if (parse_result != JNI_OK) return parse_result;
3369
3370 os::init_before_ergo();
3371
3372 jint ergo_result = Arguments::apply_ergo();
3373 if (ergo_result != JNI_OK) return ergo_result;
3374
3375 // Final check of all ranges after ergonomics which may change values.
3376 if (!CommandLineFlagRangeList::check_ranges()) {
3377 return JNI_EINVAL;
3378 }
3379
3380 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3381 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3382 if (!constraint_result) {
3383 return JNI_EINVAL;
3384 }
3385
3386 if (PauseAtStartup) {
3387 os::pause();
3388 }
3389
3390 HOTSPOT_VM_INIT_BEGIN();
3391
3392 // Timing (must come after argument parsing)
3393 TraceTime timer("Create VM", TraceStartupTime);
3394
3395 // Initialize the os module after parsing the args
3396 jint os_init_2_result = os::init_2();
3397 if (os_init_2_result != JNI_OK) return os_init_2_result;
3398
3399 jint adjust_after_os_result = Arguments::adjust_after_os();
3400 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3401
3402 // Initialize output stream logging
3403 ostream_init_log();
3404
3405 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3406 // Must be before create_vm_init_agents()
3407 if (Arguments::init_libraries_at_startup()) {
3408 convert_vm_init_libraries_to_agents();
3409 }
3410
3411 // Launch -agentlib/-agentpath and converted -Xrun agents
3412 if (Arguments::init_agents_at_startup()) {
3413 create_vm_init_agents();
3414 }
3415
3416 // Initialize Threads state
3417 _thread_list = NULL;
3418 _number_of_threads = 0;
3419 _number_of_non_daemon_threads = 0;
3420
3421 // Initialize global data structures and create system classes in heap
3422 vm_init_globals();
3423
3424 #if INCLUDE_JVMCI
3425 if (JVMCICounterSize > 0) {
3426 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3427 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3428 } else {
3429 JavaThread::_jvmci_old_thread_counters = NULL;
3430 }
3431 #endif // INCLUDE_JVMCI
3432
3433 // Attach the main thread to this os thread
3434 JavaThread* main_thread = new JavaThread();
3435 main_thread->set_thread_state(_thread_in_vm);
3436 main_thread->initialize_thread_current();
3437 // must do this before set_active_handles
3438 main_thread->record_stack_base_and_size();
3439 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3440
3441 if (!main_thread->set_as_starting_thread()) {
3442 vm_shutdown_during_initialization(
3443 "Failed necessary internal allocation. Out of swap space");
3444 delete main_thread;
3445 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3446 return JNI_ENOMEM;
3447 }
3448
3449 // Enable guard page *after* os::create_main_thread(), otherwise it would
3450 // crash Linux VM, see notes in os_linux.cpp.
3451 main_thread->create_stack_guard_pages();
3452
3453 // Initialize Java-Level synchronization subsystem
3454 ObjectMonitor::Initialize();
3455
3456 // Initialize global modules
3457 jint status = init_globals();
3458 if (status != JNI_OK) {
3459 delete main_thread;
3460 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3461 return status;
3462 }
3463
3464 // Should be done after the heap is fully created
3465 main_thread->cache_global_variables();
3466
3467 HandleMark hm;
3468
3469 { MutexLocker mu(Threads_lock);
3470 Threads::add(main_thread);
3471 }
3472
3473 // Any JVMTI raw monitors entered in onload will transition into
3474 // real raw monitor. VM is setup enough here for raw monitor enter.
3475 JvmtiExport::transition_pending_onload_raw_monitors();
3476
3477 // Create the VMThread
3478 { TraceTime timer("Start VMThread", TraceStartupTime);
3479 VMThread::create();
3480 Thread* vmthread = VMThread::vm_thread();
3481
3482 if (!os::create_thread(vmthread, os::vm_thread)) {
3483 vm_exit_during_initialization("Cannot create VM thread. "
3484 "Out of system resources.");
3485 }
3486
3487 // Wait for the VM thread to become ready, and VMThread::run to initialize
3488 // Monitors can have spurious returns, must always check another state flag
3489 {
3490 MutexLocker ml(Notify_lock);
3491 os::start_thread(vmthread);
3492 while (vmthread->active_handles() == NULL) {
3493 Notify_lock->wait();
3494 }
3495 }
3496 }
3497
3498 assert(Universe::is_fully_initialized(), "not initialized");
3499 if (VerifyDuringStartup) {
3500 // Make sure we're starting with a clean slate.
3501 VM_Verify verify_op;
3502 VMThread::execute(&verify_op);
3503 }
3504
3505 Thread* THREAD = Thread::current();
3506
3507 // At this point, the Universe is initialized, but we have not executed
3508 // any byte code. Now is a good time (the only time) to dump out the
3509 // internal state of the JVM for sharing.
3510 if (DumpSharedSpaces) {
3511 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3512 ShouldNotReachHere();
3513 }
3514
3515 // Always call even when there are not JVMTI environments yet, since environments
3516 // may be attached late and JVMTI must track phases of VM execution
3517 JvmtiExport::enter_start_phase();
3518
3519 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3520 JvmtiExport::post_vm_start();
3521
3522 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3523
3524 // We need this for ClassDataSharing - the initial vm.info property is set
3525 // with the default value of CDS "sharing" which may be reset through
3526 // command line options.
3527 reset_vm_info_property(CHECK_JNI_ERR);
3528
3529 quicken_jni_functions();
3530
3531 // Must be run after init_ft which initializes ft_enabled
3532 if (TRACE_INITIALIZE() != JNI_OK) {
3533 vm_exit_during_initialization("Failed to initialize tracing backend");
3534 }
3535
3536 // Set flag that basic initialization has completed. Used by exceptions and various
3537 // debug stuff, that does not work until all basic classes have been initialized.
3538 set_init_completed();
3539
3540 LogConfiguration::post_initialize();
3541 Metaspace::post_initialize();
3542
3543 HOTSPOT_VM_INIT_END();
3544
3545 // record VM initialization completion time
3546 #if INCLUDE_MANAGEMENT
3547 Management::record_vm_init_completed();
3548 #endif // INCLUDE_MANAGEMENT
3549
3550 // Compute system loader. Note that this has to occur after set_init_completed, since
3551 // valid exceptions may be thrown in the process.
3552 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3553 // set_init_completed has just been called, causing exceptions not to be shortcut
3554 // anymore. We call vm_exit_during_initialization directly instead.
3555 SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR));
3556
3557 #if INCLUDE_ALL_GCS
3558 // Support for ConcurrentMarkSweep. This should be cleaned up
3559 // and better encapsulated. The ugly nested if test would go away
3560 // once things are properly refactored. XXX YSR
3561 if (UseConcMarkSweepGC || UseG1GC) {
3562 if (UseConcMarkSweepGC) {
3563 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3564 } else {
3565 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3566 }
3567 }
3568 #endif // INCLUDE_ALL_GCS
3569
3570 // Always call even when there are not JVMTI environments yet, since environments
3571 // may be attached late and JVMTI must track phases of VM execution
3572 JvmtiExport::enter_live_phase();
3573
3574 // Signal Dispatcher needs to be started before VMInit event is posted
3575 os::signal_init();
3576
3577 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3578 if (!DisableAttachMechanism) {
3579 AttachListener::vm_start();
3580 if (StartAttachListener || AttachListener::init_at_startup()) {
3581 AttachListener::init();
3582 }
3583 }
3584
3585 // Launch -Xrun agents
3586 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3587 // back-end can launch with -Xdebug -Xrunjdwp.
3588 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3589 create_vm_init_libraries();
3590 }
3591
3592 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3593 JvmtiExport::post_vm_initialized();
3594
3595 if (TRACE_START() != JNI_OK) {
3596 vm_exit_during_initialization("Failed to start tracing backend.");
3597 }
3598
3599 if (CleanChunkPoolAsync) {
3600 Chunk::start_chunk_pool_cleaner_task();
3601 }
3602
3603 #if INCLUDE_JVMCI
3604 if (EnableJVMCI) {
3605 const char* jvmciCompiler = Arguments::PropertyList_get_value(Arguments::system_properties(), "jvmci.compiler");
3606 if (jvmciCompiler != NULL) {
3607 JVMCIRuntime::save_compiler(jvmciCompiler);
3608 }
3609 }
3610 #endif // INCLUDE_JVMCI
3611
3612 // initialize compiler(s)
3613 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI
3614 CompileBroker::compilation_init();
3615 #endif
3616
3617 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3618 // It is done after compilers are initialized, because otherwise compilations of
3619 // signature polymorphic MH intrinsics can be missed
3620 // (see SystemDictionary::find_method_handle_intrinsic).
3621 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3622
3623 #if INCLUDE_MANAGEMENT
3624 Management::initialize(THREAD);
3625
3626 if (HAS_PENDING_EXCEPTION) {
3627 // management agent fails to start possibly due to
3628 // configuration problem and is responsible for printing
3629 // stack trace if appropriate. Simply exit VM.
3630 vm_exit(1);
3631 }
3632 #endif // INCLUDE_MANAGEMENT
3633
3634 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3635 if (MemProfiling) MemProfiler::engage();
3636 StatSampler::engage();
3637 if (CheckJNICalls) JniPeriodicChecker::engage();
3638
3639 BiasedLocking::init();
3640
3641 #if INCLUDE_RTM_OPT
3642 RTMLockingCounters::init();
3643 #endif
3644
3645 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3646 call_postVMInitHook(THREAD);
3647 // The Java side of PostVMInitHook.run must deal with all
3648 // exceptions and provide means of diagnosis.
3649 if (HAS_PENDING_EXCEPTION) {
3650 CLEAR_PENDING_EXCEPTION;
3651 }
3652 }
3653
3654 {
3655 MutexLocker ml(PeriodicTask_lock);
3656 // Make sure the WatcherThread can be started by WatcherThread::start()
3657 // or by dynamic enrollment.
3658 WatcherThread::make_startable();
3659 // Start up the WatcherThread if there are any periodic tasks
3660 // NOTE: All PeriodicTasks should be registered by now. If they
3661 // aren't, late joiners might appear to start slowly (we might
3662 // take a while to process their first tick).
3663 if (PeriodicTask::num_tasks() > 0) {
3664 WatcherThread::start();
3665 }
3666 }
3667
3668 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3669
3670 create_vm_timer.end();
3671 #ifdef ASSERT
3672 _vm_complete = true;
3673 #endif
3674 return JNI_OK;
3675 }
3676
3677 // type for the Agent_OnLoad and JVM_OnLoad entry points
3678 extern "C" {
3679 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3680 }
3681 // Find a command line agent library and return its entry point for
3682 // -agentlib: -agentpath: -Xrun
3683 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3684 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3685 const char *on_load_symbols[],
3686 size_t num_symbol_entries) {
3687 OnLoadEntry_t on_load_entry = NULL;
3688 void *library = NULL;
3689
3690 if (!agent->valid()) {
3691 char buffer[JVM_MAXPATHLEN];
3692 char ebuf[1024] = "";
3693 const char *name = agent->name();
3694 const char *msg = "Could not find agent library ";
3695
3696 // First check to see if agent is statically linked into executable
3697 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3698 library = agent->os_lib();
3699 } else if (agent->is_absolute_path()) {
3700 library = os::dll_load(name, ebuf, sizeof ebuf);
3701 if (library == NULL) {
3702 const char *sub_msg = " in absolute path, with error: ";
3703 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3704 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3705 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3706 // If we can't find the agent, exit.
3707 vm_exit_during_initialization(buf, NULL);
3708 FREE_C_HEAP_ARRAY(char, buf);
3709 }
3710 } else {
3711 // Try to load the agent from the standard dll directory
3712 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3713 name)) {
3714 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3715 }
3716 if (library == NULL) { // Try the local directory
3717 char ns[1] = {0};
3718 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3719 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3720 }
3721 if (library == NULL) {
3722 const char *sub_msg = " on the library path, with error: ";
3723 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3724 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3725 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3726 // If we can't find the agent, exit.
3727 vm_exit_during_initialization(buf, NULL);
3728 FREE_C_HEAP_ARRAY(char, buf);
3729 }
3730 }
3731 }
3732 agent->set_os_lib(library);
3733 agent->set_valid();
3734 }
3735
3736 // Find the OnLoad function.
3737 on_load_entry =
3738 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3739 false,
3740 on_load_symbols,
3741 num_symbol_entries));
3742 return on_load_entry;
3743 }
3744
3745 // Find the JVM_OnLoad entry point
3746 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3747 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3748 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3749 }
3750
3751 // Find the Agent_OnLoad entry point
3752 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3753 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3754 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3755 }
3756
3757 // For backwards compatibility with -Xrun
3758 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3759 // treated like -agentpath:
3760 // Must be called before agent libraries are created
3761 void Threads::convert_vm_init_libraries_to_agents() {
3762 AgentLibrary* agent;
3763 AgentLibrary* next;
3764
3765 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3766 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3767 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3768
3769 // If there is an JVM_OnLoad function it will get called later,
3770 // otherwise see if there is an Agent_OnLoad
3771 if (on_load_entry == NULL) {
3772 on_load_entry = lookup_agent_on_load(agent);
3773 if (on_load_entry != NULL) {
3774 // switch it to the agent list -- so that Agent_OnLoad will be called,
3775 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3776 Arguments::convert_library_to_agent(agent);
3777 } else {
3778 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3779 }
3780 }
3781 }
3782 }
3783
3784 // Create agents for -agentlib: -agentpath: and converted -Xrun
3785 // Invokes Agent_OnLoad
3786 // Called very early -- before JavaThreads exist
3787 void Threads::create_vm_init_agents() {
3788 extern struct JavaVM_ main_vm;
3789 AgentLibrary* agent;
3790
3791 JvmtiExport::enter_onload_phase();
3792
3793 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3794 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3795
3796 if (on_load_entry != NULL) {
3797 // Invoke the Agent_OnLoad function
3798 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3799 if (err != JNI_OK) {
3800 vm_exit_during_initialization("agent library failed to init", agent->name());
3801 }
3802 } else {
3803 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3804 }
3805 }
3806 JvmtiExport::enter_primordial_phase();
3807 }
3808
3809 extern "C" {
3810 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3811 }
3812
3813 void Threads::shutdown_vm_agents() {
3814 // Send any Agent_OnUnload notifications
3815 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3816 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3817 extern struct JavaVM_ main_vm;
3818 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3819
3820 // Find the Agent_OnUnload function.
3821 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3822 os::find_agent_function(agent,
3823 false,
3824 on_unload_symbols,
3825 num_symbol_entries));
3826
3827 // Invoke the Agent_OnUnload function
3828 if (unload_entry != NULL) {
3829 JavaThread* thread = JavaThread::current();
3830 ThreadToNativeFromVM ttn(thread);
3831 HandleMark hm(thread);
3832 (*unload_entry)(&main_vm);
3833 }
3834 }
3835 }
3836
3837 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3838 // Invokes JVM_OnLoad
3839 void Threads::create_vm_init_libraries() {
3840 extern struct JavaVM_ main_vm;
3841 AgentLibrary* agent;
3842
3843 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3844 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3845
3846 if (on_load_entry != NULL) {
3847 // Invoke the JVM_OnLoad function
3848 JavaThread* thread = JavaThread::current();
3849 ThreadToNativeFromVM ttn(thread);
3850 HandleMark hm(thread);
3851 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3852 if (err != JNI_OK) {
3853 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3854 }
3855 } else {
3856 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3857 }
3858 }
3859 }
3860
3861 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3862 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3863
3864 JavaThread* java_thread = NULL;
3865 // Sequential search for now. Need to do better optimization later.
3866 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3867 oop tobj = thread->threadObj();
3868 if (!thread->is_exiting() &&
3869 tobj != NULL &&
3870 java_tid == java_lang_Thread::thread_id(tobj)) {
3871 java_thread = thread;
3872 break;
3873 }
3874 }
3875 return java_thread;
3876 }
3877
3878
3879 // Last thread running calls java.lang.Shutdown.shutdown()
3880 void JavaThread::invoke_shutdown_hooks() {
3881 HandleMark hm(this);
3882
3883 // We could get here with a pending exception, if so clear it now.
3884 if (this->has_pending_exception()) {
3885 this->clear_pending_exception();
3886 }
3887
3888 EXCEPTION_MARK;
3889 Klass* k =
3890 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3891 THREAD);
3892 if (k != NULL) {
3893 // SystemDictionary::resolve_or_null will return null if there was
3894 // an exception. If we cannot load the Shutdown class, just don't
3895 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3896 // and finalizers (if runFinalizersOnExit is set) won't be run.
3897 // Note that if a shutdown hook was registered or runFinalizersOnExit
3898 // was called, the Shutdown class would have already been loaded
3899 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3900 instanceKlassHandle shutdown_klass (THREAD, k);
3901 JavaValue result(T_VOID);
3902 JavaCalls::call_static(&result,
3903 shutdown_klass,
3904 vmSymbols::shutdown_method_name(),
3905 vmSymbols::void_method_signature(),
3906 THREAD);
3907 }
3908 CLEAR_PENDING_EXCEPTION;
3909 }
3910
3911 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3912 // the program falls off the end of main(). Another VM exit path is through
3913 // vm_exit() when the program calls System.exit() to return a value or when
3914 // there is a serious error in VM. The two shutdown paths are not exactly
3915 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3916 // and VM_Exit op at VM level.
3917 //
3918 // Shutdown sequence:
3919 // + Shutdown native memory tracking if it is on
3920 // + Wait until we are the last non-daemon thread to execute
3921 // <-- every thing is still working at this moment -->
3922 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3923 // shutdown hooks, run finalizers if finalization-on-exit
3924 // + Call before_exit(), prepare for VM exit
3925 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3926 // currently the only user of this mechanism is File.deleteOnExit())
3927 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3928 // post thread end and vm death events to JVMTI,
3929 // stop signal thread
3930 // + Call JavaThread::exit(), it will:
3931 // > release JNI handle blocks, remove stack guard pages
3932 // > remove this thread from Threads list
3933 // <-- no more Java code from this thread after this point -->
3934 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3935 // the compiler threads at safepoint
3936 // <-- do not use anything that could get blocked by Safepoint -->
3937 // + Disable tracing at JNI/JVM barriers
3938 // + Set _vm_exited flag for threads that are still running native code
3939 // + Delete this thread
3940 // + Call exit_globals()
3941 // > deletes tty
3942 // > deletes PerfMemory resources
3943 // + Return to caller
3944
3945 bool Threads::destroy_vm() {
3946 JavaThread* thread = JavaThread::current();
3947
3948 #ifdef ASSERT
3949 _vm_complete = false;
3950 #endif
3951 // Wait until we are the last non-daemon thread to execute
3952 { MutexLocker nu(Threads_lock);
3953 while (Threads::number_of_non_daemon_threads() > 1)
3954 // This wait should make safepoint checks, wait without a timeout,
3955 // and wait as a suspend-equivalent condition.
3956 //
3957 // Note: If the FlatProfiler is running and this thread is waiting
3958 // for another non-daemon thread to finish, then the FlatProfiler
3959 // is waiting for the external suspend request on this thread to
3960 // complete. wait_for_ext_suspend_completion() will eventually
3961 // timeout, but that takes time. Making this wait a suspend-
3962 // equivalent condition solves that timeout problem.
3963 //
3964 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3965 Mutex::_as_suspend_equivalent_flag);
3966 }
3967
3968 // Hang forever on exit if we are reporting an error.
3969 if (ShowMessageBoxOnError && is_error_reported()) {
3970 os::infinite_sleep();
3971 }
3972 os::wait_for_keypress_at_exit();
3973
3974 // run Java level shutdown hooks
3975 thread->invoke_shutdown_hooks();
3976
3977 before_exit(thread);
3978
3979 thread->exit(true);
3980
3981 // Stop VM thread.
3982 {
3983 // 4945125 The vm thread comes to a safepoint during exit.
3984 // GC vm_operations can get caught at the safepoint, and the
3985 // heap is unparseable if they are caught. Grab the Heap_lock
3986 // to prevent this. The GC vm_operations will not be able to
3987 // queue until after the vm thread is dead. After this point,
3988 // we'll never emerge out of the safepoint before the VM exits.
3989
3990 MutexLocker ml(Heap_lock);
3991
3992 VMThread::wait_for_vm_thread_exit();
3993 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3994 VMThread::destroy();
3995 }
3996
3997 // clean up ideal graph printers
3998 #if defined(COMPILER2) && !defined(PRODUCT)
3999 IdealGraphPrinter::clean_up();
4000 #endif
4001
4002 // Now, all Java threads are gone except daemon threads. Daemon threads
4003 // running Java code or in VM are stopped by the Safepoint. However,
4004 // daemon threads executing native code are still running. But they
4005 // will be stopped at native=>Java/VM barriers. Note that we can't
4006 // simply kill or suspend them, as it is inherently deadlock-prone.
4007
4008 #ifndef PRODUCT
4009 // disable function tracing at JNI/JVM barriers
4010 TraceJNICalls = false;
4011 TraceJVMCalls = false;
4012 TraceRuntimeCalls = false;
4013 #endif
4014
4015 VM_Exit::set_vm_exited();
4016
4017 notify_vm_shutdown();
4018
4019 delete thread;
4020
4021 #if INCLUDE_JVMCI
4022 if (JVMCICounterSize > 0) {
4023 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4024 }
4025 #endif
4026
4027 // exit_globals() will delete tty
4028 exit_globals();
4029
4030 LogConfiguration::finalize();
4031
4032 return true;
4033 }
4034
4035
4036 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4037 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4038 return is_supported_jni_version(version);
4039 }
4040
4041
4042 jboolean Threads::is_supported_jni_version(jint version) {
4043 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4044 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4045 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4046 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4047 return JNI_FALSE;
4048 }
4049
4050
4051 void Threads::add(JavaThread* p, bool force_daemon) {
4052 // The threads lock must be owned at this point
4053 assert_locked_or_safepoint(Threads_lock);
4054
4055 // See the comment for this method in thread.hpp for its purpose and
4056 // why it is called here.
4057 p->initialize_queues();
4058 p->set_next(_thread_list);
4059 _thread_list = p;
4060 _number_of_threads++;
4061 oop threadObj = p->threadObj();
4062 bool daemon = true;
4063 // Bootstrapping problem: threadObj can be null for initial
4064 // JavaThread (or for threads attached via JNI)
4065 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4066 _number_of_non_daemon_threads++;
4067 daemon = false;
4068 }
4069
4070 ThreadService::add_thread(p, daemon);
4071
4072 // Possible GC point.
4073 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4074 }
4075
4076 void Threads::remove(JavaThread* p) {
4077 // Extra scope needed for Thread_lock, so we can check
4078 // that we do not remove thread without safepoint code notice
4079 { MutexLocker ml(Threads_lock);
4080
4081 assert(includes(p), "p must be present");
4082
4083 JavaThread* current = _thread_list;
4084 JavaThread* prev = NULL;
4085
4086 while (current != p) {
4087 prev = current;
4088 current = current->next();
4089 }
4090
4091 if (prev) {
4092 prev->set_next(current->next());
4093 } else {
4094 _thread_list = p->next();
4095 }
4096 _number_of_threads--;
4097 oop threadObj = p->threadObj();
4098 bool daemon = true;
4099 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4100 _number_of_non_daemon_threads--;
4101 daemon = false;
4102
4103 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4104 // on destroy_vm will wake up.
4105 if (number_of_non_daemon_threads() == 1) {
4106 Threads_lock->notify_all();
4107 }
4108 }
4109 ThreadService::remove_thread(p, daemon);
4110
4111 // Make sure that safepoint code disregard this thread. This is needed since
4112 // the thread might mess around with locks after this point. This can cause it
4113 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4114 // of this thread since it is removed from the queue.
4115 p->set_terminated_value();
4116 } // unlock Threads_lock
4117
4118 // Since Events::log uses a lock, we grab it outside the Threads_lock
4119 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4120 }
4121
4122 // Threads_lock must be held when this is called (or must be called during a safepoint)
4123 bool Threads::includes(JavaThread* p) {
4124 assert(Threads_lock->is_locked(), "sanity check");
4125 ALL_JAVA_THREADS(q) {
4126 if (q == p) {
4127 return true;
4128 }
4129 }
4130 return false;
4131 }
4132
4133 // Operations on the Threads list for GC. These are not explicitly locked,
4134 // but the garbage collector must provide a safe context for them to run.
4135 // In particular, these things should never be called when the Threads_lock
4136 // is held by some other thread. (Note: the Safepoint abstraction also
4137 // uses the Threads_lock to guarantee this property. It also makes sure that
4138 // all threads gets blocked when exiting or starting).
4139
4140 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4141 ALL_JAVA_THREADS(p) {
4142 p->oops_do(f, cld_f, cf);
4143 }
4144 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4145 }
4146
4147 void Threads::change_thread_claim_parity() {
4148 // Set the new claim parity.
4149 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4150 "Not in range.");
4151 _thread_claim_parity++;
4152 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4153 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4154 "Not in range.");
4155 }
4156
4157 #ifdef ASSERT
4158 void Threads::assert_all_threads_claimed() {
4159 ALL_JAVA_THREADS(p) {
4160 const int thread_parity = p->oops_do_parity();
4161 assert((thread_parity == _thread_claim_parity),
4162 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4163 }
4164 }
4165 #endif // ASSERT
4166
4167 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4168 int cp = Threads::thread_claim_parity();
4169 ALL_JAVA_THREADS(p) {
4170 if (p->claim_oops_do(is_par, cp)) {
4171 p->oops_do(f, cld_f, cf);
4172 }
4173 }
4174 VMThread* vmt = VMThread::vm_thread();
4175 if (vmt->claim_oops_do(is_par, cp)) {
4176 vmt->oops_do(f, cld_f, cf);
4177 }
4178 }
4179
4180 #if INCLUDE_ALL_GCS
4181 // Used by ParallelScavenge
4182 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4183 ALL_JAVA_THREADS(p) {
4184 q->enqueue(new ThreadRootsTask(p));
4185 }
4186 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4187 }
4188
4189 // Used by Parallel Old
4190 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4191 ALL_JAVA_THREADS(p) {
4192 q->enqueue(new ThreadRootsMarkingTask(p));
4193 }
4194 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4195 }
4196 #endif // INCLUDE_ALL_GCS
4197
4198 void Threads::nmethods_do(CodeBlobClosure* cf) {
4199 ALL_JAVA_THREADS(p) {
4200 p->nmethods_do(cf);
4201 }
4202 VMThread::vm_thread()->nmethods_do(cf);
4203 }
4204
4205 void Threads::metadata_do(void f(Metadata*)) {
4206 ALL_JAVA_THREADS(p) {
4207 p->metadata_do(f);
4208 }
4209 }
4210
4211 class ThreadHandlesClosure : public ThreadClosure {
4212 void (*_f)(Metadata*);
4213 public:
4214 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4215 virtual void do_thread(Thread* thread) {
4216 thread->metadata_handles_do(_f);
4217 }
4218 };
4219
4220 void Threads::metadata_handles_do(void f(Metadata*)) {
4221 // Only walk the Handles in Thread.
4222 ThreadHandlesClosure handles_closure(f);
4223 threads_do(&handles_closure);
4224 }
4225
4226 void Threads::deoptimized_wrt_marked_nmethods() {
4227 ALL_JAVA_THREADS(p) {
4228 p->deoptimized_wrt_marked_nmethods();
4229 }
4230 }
4231
4232
4233 // Get count Java threads that are waiting to enter the specified monitor.
4234 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4235 address monitor,
4236 bool doLock) {
4237 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4238 "must grab Threads_lock or be at safepoint");
4239 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4240
4241 int i = 0;
4242 {
4243 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4244 ALL_JAVA_THREADS(p) {
4245 if (!p->can_call_java()) continue;
4246
4247 address pending = (address)p->current_pending_monitor();
4248 if (pending == monitor) { // found a match
4249 if (i < count) result->append(p); // save the first count matches
4250 i++;
4251 }
4252 }
4253 }
4254 return result;
4255 }
4256
4257
4258 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4259 bool doLock) {
4260 assert(doLock ||
4261 Threads_lock->owned_by_self() ||
4262 SafepointSynchronize::is_at_safepoint(),
4263 "must grab Threads_lock or be at safepoint");
4264
4265 // NULL owner means not locked so we can skip the search
4266 if (owner == NULL) return NULL;
4267
4268 {
4269 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4270 ALL_JAVA_THREADS(p) {
4271 // first, see if owner is the address of a Java thread
4272 if (owner == (address)p) return p;
4273 }
4274 }
4275 // Cannot assert on lack of success here since this function may be
4276 // used by code that is trying to report useful problem information
4277 // like deadlock detection.
4278 if (UseHeavyMonitors) return NULL;
4279
4280 // If we didn't find a matching Java thread and we didn't force use of
4281 // heavyweight monitors, then the owner is the stack address of the
4282 // Lock Word in the owning Java thread's stack.
4283 //
4284 JavaThread* the_owner = NULL;
4285 {
4286 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4287 ALL_JAVA_THREADS(q) {
4288 if (q->is_lock_owned(owner)) {
4289 the_owner = q;
4290 break;
4291 }
4292 }
4293 }
4294 // cannot assert on lack of success here; see above comment
4295 return the_owner;
4296 }
4297
4298 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4299 void Threads::print_on(outputStream* st, bool print_stacks,
4300 bool internal_format, bool print_concurrent_locks) {
4301 char buf[32];
4302 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4303
4304 st->print_cr("Full thread dump %s (%s %s):",
4305 Abstract_VM_Version::vm_name(),
4306 Abstract_VM_Version::vm_release(),
4307 Abstract_VM_Version::vm_info_string());
4308 st->cr();
4309
4310 #if INCLUDE_SERVICES
4311 // Dump concurrent locks
4312 ConcurrentLocksDump concurrent_locks;
4313 if (print_concurrent_locks) {
4314 concurrent_locks.dump_at_safepoint();
4315 }
4316 #endif // INCLUDE_SERVICES
4317
4318 ALL_JAVA_THREADS(p) {
4319 ResourceMark rm;
4320 p->print_on(st);
4321 if (print_stacks) {
4322 if (internal_format) {
4323 p->trace_stack();
4324 } else {
4325 p->print_stack_on(st);
4326 }
4327 }
4328 st->cr();
4329 #if INCLUDE_SERVICES
4330 if (print_concurrent_locks) {
4331 concurrent_locks.print_locks_on(p, st);
4332 }
4333 #endif // INCLUDE_SERVICES
4334 }
4335
4336 VMThread::vm_thread()->print_on(st);
4337 st->cr();
4338 Universe::heap()->print_gc_threads_on(st);
4339 WatcherThread* wt = WatcherThread::watcher_thread();
4340 if (wt != NULL) {
4341 wt->print_on(st);
4342 st->cr();
4343 }
4344 CompileBroker::print_compiler_threads_on(st);
4345 st->flush();
4346 }
4347
4348 // Threads::print_on_error() is called by fatal error handler. It's possible
4349 // that VM is not at safepoint and/or current thread is inside signal handler.
4350 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4351 // memory (even in resource area), it might deadlock the error handler.
4352 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4353 int buflen) {
4354 bool found_current = false;
4355 st->print_cr("Java Threads: ( => current thread )");
4356 ALL_JAVA_THREADS(thread) {
4357 bool is_current = (current == thread);
4358 found_current = found_current || is_current;
4359
4360 st->print("%s", is_current ? "=>" : " ");
4361
4362 st->print(PTR_FORMAT, p2i(thread));
4363 st->print(" ");
4364 thread->print_on_error(st, buf, buflen);
4365 st->cr();
4366 }
4367 st->cr();
4368
4369 st->print_cr("Other Threads:");
4370 if (VMThread::vm_thread()) {
4371 bool is_current = (current == VMThread::vm_thread());
4372 found_current = found_current || is_current;
4373 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4374
4375 st->print(PTR_FORMAT, p2i(VMThread::vm_thread()));
4376 st->print(" ");
4377 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4378 st->cr();
4379 }
4380 WatcherThread* wt = WatcherThread::watcher_thread();
4381 if (wt != NULL) {
4382 bool is_current = (current == wt);
4383 found_current = found_current || is_current;
4384 st->print("%s", is_current ? "=>" : " ");
4385
4386 st->print(PTR_FORMAT, p2i(wt));
4387 st->print(" ");
4388 wt->print_on_error(st, buf, buflen);
4389 st->cr();
4390 }
4391 if (!found_current) {
4392 st->cr();
4393 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4394 current->print_on_error(st, buf, buflen);
4395 st->cr();
4396 }
4397 }
4398
4399 // Internal SpinLock and Mutex
4400 // Based on ParkEvent
4401
4402 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4403 //
4404 // We employ SpinLocks _only for low-contention, fixed-length
4405 // short-duration critical sections where we're concerned
4406 // about native mutex_t or HotSpot Mutex:: latency.
4407 // The mux construct provides a spin-then-block mutual exclusion
4408 // mechanism.
4409 //
4410 // Testing has shown that contention on the ListLock guarding gFreeList
4411 // is common. If we implement ListLock as a simple SpinLock it's common
4412 // for the JVM to devolve to yielding with little progress. This is true
4413 // despite the fact that the critical sections protected by ListLock are
4414 // extremely short.
4415 //
4416 // TODO-FIXME: ListLock should be of type SpinLock.
4417 // We should make this a 1st-class type, integrated into the lock
4418 // hierarchy as leaf-locks. Critically, the SpinLock structure
4419 // should have sufficient padding to avoid false-sharing and excessive
4420 // cache-coherency traffic.
4421
4422
4423 typedef volatile int SpinLockT;
4424
4425 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4426 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4427 return; // normal fast-path return
4428 }
4429
4430 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4431 TEVENT(SpinAcquire - ctx);
4432 int ctr = 0;
4433 int Yields = 0;
4434 for (;;) {
4435 while (*adr != 0) {
4436 ++ctr;
4437 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4438 if (Yields > 5) {
4439 os::naked_short_sleep(1);
4440 } else {
4441 os::naked_yield();
4442 ++Yields;
4443 }
4444 } else {
4445 SpinPause();
4446 }
4447 }
4448 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4449 }
4450 }
4451
4452 void Thread::SpinRelease(volatile int * adr) {
4453 assert(*adr != 0, "invariant");
4454 OrderAccess::fence(); // guarantee at least release consistency.
4455 // Roach-motel semantics.
4456 // It's safe if subsequent LDs and STs float "up" into the critical section,
4457 // but prior LDs and STs within the critical section can't be allowed
4458 // to reorder or float past the ST that releases the lock.
4459 // Loads and stores in the critical section - which appear in program
4460 // order before the store that releases the lock - must also appear
4461 // before the store that releases the lock in memory visibility order.
4462 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4463 // the ST of 0 into the lock-word which releases the lock, so fence
4464 // more than covers this on all platforms.
4465 *adr = 0;
4466 }
4467
4468 // muxAcquire and muxRelease:
4469 //
4470 // * muxAcquire and muxRelease support a single-word lock-word construct.
4471 // The LSB of the word is set IFF the lock is held.
4472 // The remainder of the word points to the head of a singly-linked list
4473 // of threads blocked on the lock.
4474 //
4475 // * The current implementation of muxAcquire-muxRelease uses its own
4476 // dedicated Thread._MuxEvent instance. If we're interested in
4477 // minimizing the peak number of extant ParkEvent instances then
4478 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4479 // as certain invariants were satisfied. Specifically, care would need
4480 // to be taken with regards to consuming unpark() "permits".
4481 // A safe rule of thumb is that a thread would never call muxAcquire()
4482 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4483 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4484 // consume an unpark() permit intended for monitorenter, for instance.
4485 // One way around this would be to widen the restricted-range semaphore
4486 // implemented in park(). Another alternative would be to provide
4487 // multiple instances of the PlatformEvent() for each thread. One
4488 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4489 //
4490 // * Usage:
4491 // -- Only as leaf locks
4492 // -- for short-term locking only as muxAcquire does not perform
4493 // thread state transitions.
4494 //
4495 // Alternatives:
4496 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4497 // but with parking or spin-then-park instead of pure spinning.
4498 // * Use Taura-Oyama-Yonenzawa locks.
4499 // * It's possible to construct a 1-0 lock if we encode the lockword as
4500 // (List,LockByte). Acquire will CAS the full lockword while Release
4501 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4502 // acquiring threads use timers (ParkTimed) to detect and recover from
4503 // the stranding window. Thread/Node structures must be aligned on 256-byte
4504 // boundaries by using placement-new.
4505 // * Augment MCS with advisory back-link fields maintained with CAS().
4506 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4507 // The validity of the backlinks must be ratified before we trust the value.
4508 // If the backlinks are invalid the exiting thread must back-track through the
4509 // the forward links, which are always trustworthy.
4510 // * Add a successor indication. The LockWord is currently encoded as
4511 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4512 // to provide the usual futile-wakeup optimization.
4513 // See RTStt for details.
4514 // * Consider schedctl.sc_nopreempt to cover the critical section.
4515 //
4516
4517
4518 typedef volatile intptr_t MutexT; // Mux Lock-word
4519 enum MuxBits { LOCKBIT = 1 };
4520
4521 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4522 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4523 if (w == 0) return;
4524 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4525 return;
4526 }
4527
4528 TEVENT(muxAcquire - Contention);
4529 ParkEvent * const Self = Thread::current()->_MuxEvent;
4530 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4531 for (;;) {
4532 int its = (os::is_MP() ? 100 : 0) + 1;
4533
4534 // Optional spin phase: spin-then-park strategy
4535 while (--its >= 0) {
4536 w = *Lock;
4537 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4538 return;
4539 }
4540 }
4541
4542 Self->reset();
4543 Self->OnList = intptr_t(Lock);
4544 // The following fence() isn't _strictly necessary as the subsequent
4545 // CAS() both serializes execution and ratifies the fetched *Lock value.
4546 OrderAccess::fence();
4547 for (;;) {
4548 w = *Lock;
4549 if ((w & LOCKBIT) == 0) {
4550 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4551 Self->OnList = 0; // hygiene - allows stronger asserts
4552 return;
4553 }
4554 continue; // Interference -- *Lock changed -- Just retry
4555 }
4556 assert(w & LOCKBIT, "invariant");
4557 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4558 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4559 }
4560
4561 while (Self->OnList != 0) {
4562 Self->park();
4563 }
4564 }
4565 }
4566
4567 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4568 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4569 if (w == 0) return;
4570 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4571 return;
4572 }
4573
4574 TEVENT(muxAcquire - Contention);
4575 ParkEvent * ReleaseAfter = NULL;
4576 if (ev == NULL) {
4577 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4578 }
4579 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4580 for (;;) {
4581 guarantee(ev->OnList == 0, "invariant");
4582 int its = (os::is_MP() ? 100 : 0) + 1;
4583
4584 // Optional spin phase: spin-then-park strategy
4585 while (--its >= 0) {
4586 w = *Lock;
4587 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4588 if (ReleaseAfter != NULL) {
4589 ParkEvent::Release(ReleaseAfter);
4590 }
4591 return;
4592 }
4593 }
4594
4595 ev->reset();
4596 ev->OnList = intptr_t(Lock);
4597 // The following fence() isn't _strictly necessary as the subsequent
4598 // CAS() both serializes execution and ratifies the fetched *Lock value.
4599 OrderAccess::fence();
4600 for (;;) {
4601 w = *Lock;
4602 if ((w & LOCKBIT) == 0) {
4603 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4604 ev->OnList = 0;
4605 // We call ::Release while holding the outer lock, thus
4606 // artificially lengthening the critical section.
4607 // Consider deferring the ::Release() until the subsequent unlock(),
4608 // after we've dropped the outer lock.
4609 if (ReleaseAfter != NULL) {
4610 ParkEvent::Release(ReleaseAfter);
4611 }
4612 return;
4613 }
4614 continue; // Interference -- *Lock changed -- Just retry
4615 }
4616 assert(w & LOCKBIT, "invariant");
4617 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4618 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4619 }
4620
4621 while (ev->OnList != 0) {
4622 ev->park();
4623 }
4624 }
4625 }
4626
4627 // Release() must extract a successor from the list and then wake that thread.
4628 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4629 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4630 // Release() would :
4631 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4632 // (B) Extract a successor from the private list "in-hand"
4633 // (C) attempt to CAS() the residual back into *Lock over null.
4634 // If there were any newly arrived threads and the CAS() would fail.
4635 // In that case Release() would detach the RATs, re-merge the list in-hand
4636 // with the RATs and repeat as needed. Alternately, Release() might
4637 // detach and extract a successor, but then pass the residual list to the wakee.
4638 // The wakee would be responsible for reattaching and remerging before it
4639 // competed for the lock.
4640 //
4641 // Both "pop" and DMR are immune from ABA corruption -- there can be
4642 // multiple concurrent pushers, but only one popper or detacher.
4643 // This implementation pops from the head of the list. This is unfair,
4644 // but tends to provide excellent throughput as hot threads remain hot.
4645 // (We wake recently run threads first).
4646 //
4647 // All paths through muxRelease() will execute a CAS.
4648 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4649 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4650 // executed within the critical section are complete and globally visible before the
4651 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4652 void Thread::muxRelease(volatile intptr_t * Lock) {
4653 for (;;) {
4654 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4655 assert(w & LOCKBIT, "invariant");
4656 if (w == LOCKBIT) return;
4657 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4658 assert(List != NULL, "invariant");
4659 assert(List->OnList == intptr_t(Lock), "invariant");
4660 ParkEvent * const nxt = List->ListNext;
4661 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4662
4663 // The following CAS() releases the lock and pops the head element.
4664 // The CAS() also ratifies the previously fetched lock-word value.
4665 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4666 continue;
4667 }
4668 List->OnList = 0;
4669 OrderAccess::fence();
4670 List->unpark();
4671 return;
4672 }
4673 }
4674
4675
4676 void Threads::verify() {
4677 ALL_JAVA_THREADS(p) {
4678 p->verify();
4679 }
4680 VMThread* thread = VMThread::vm_thread();
4681 if (thread != NULL) thread->verify();
4682 }