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 void Thread::initialize_thread_current() {
286 assert(_thr_current == NULL, "Thread::current already initialized");
287 _thr_current = this;
288 }
289
290 void Thread::clear_thread_current() {
291 _thr_current = NULL;
292 }
293
294 void Thread::record_stack_base_and_size() {
295 set_stack_base(os::current_stack_base());
296 set_stack_size(os::current_stack_size());
297 if (is_Java_thread()) {
298 ((JavaThread*) this)->set_stack_overflow_limit();
299 }
300 // CR 7190089: on Solaris, primordial thread's stack is adjusted
301 // in initialize_thread(). Without the adjustment, stack size is
302 // incorrect if stack is set to unlimited (ulimit -s unlimited).
303 // So far, only Solaris has real implementation of initialize_thread().
304 //
305 // set up any platform-specific state.
306 os::initialize_thread(this);
307
308 #if INCLUDE_NMT
309 // record thread's native stack, stack grows downward
310 address stack_low_addr = stack_base() - stack_size();
311 MemTracker::record_thread_stack(stack_low_addr, stack_size());
312 #endif // INCLUDE_NMT
313 }
314
315
316 Thread::~Thread() {
317 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
318 ObjectSynchronizer::omFlush(this);
319
320 EVENT_THREAD_DESTRUCT(this);
321
322 // stack_base can be NULL if the thread is never started or exited before
323 // record_stack_base_and_size called. Although, we would like to ensure
324 // that all started threads do call record_stack_base_and_size(), there is
325 // not proper way to enforce that.
326 #if INCLUDE_NMT
327 if (_stack_base != NULL) {
328 address low_stack_addr = stack_base() - stack_size();
329 MemTracker::release_thread_stack(low_stack_addr, stack_size());
330 #ifdef ASSERT
331 set_stack_base(NULL);
332 #endif
333 }
334 #endif // INCLUDE_NMT
335
336 // deallocate data structures
337 delete resource_area();
338 // since the handle marks are using the handle area, we have to deallocated the root
339 // handle mark before deallocating the thread's handle area,
340 assert(last_handle_mark() != NULL, "check we have an element");
341 delete last_handle_mark();
342 assert(last_handle_mark() == NULL, "check we have reached the end");
343
344 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
345 // We NULL out the fields for good hygiene.
346 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
347 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
348 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
349 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
350
351 delete handle_area();
352 delete metadata_handles();
353
354 // osthread() can be NULL, if creation of thread failed.
355 if (osthread() != NULL) os::free_thread(osthread());
356
357 delete _SR_lock;
358
359 // clear Thread::current if thread is deleting itself.
360 // Needed to ensure JNI correctly detects non-attached threads.
361 if (this == Thread::current()) {
362 clear_thread_current();
363 }
364
365 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
366 }
367
368 // NOTE: dummy function for assertion purpose.
369 void Thread::run() {
370 ShouldNotReachHere();
371 }
372
373 #ifdef ASSERT
374 // Private method to check for dangling thread pointer
375 void check_for_dangling_thread_pointer(Thread *thread) {
376 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
377 "possibility of dangling Thread pointer");
378 }
379 #endif
380
381 ThreadPriority Thread::get_priority(const Thread* const thread) {
382 ThreadPriority priority;
383 // Can return an error!
384 (void)os::get_priority(thread, priority);
385 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
386 return priority;
387 }
388
389 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
390 debug_only(check_for_dangling_thread_pointer(thread);)
391 // Can return an error!
392 (void)os::set_priority(thread, priority);
393 }
394
395
396 void Thread::start(Thread* thread) {
397 // Start is different from resume in that its safety is guaranteed by context or
398 // being called from a Java method synchronized on the Thread object.
399 if (!DisableStartThread) {
400 if (thread->is_Java_thread()) {
401 // Initialize the thread state to RUNNABLE before starting this thread.
402 // Can not set it after the thread started because we do not know the
403 // exact thread state at that time. It could be in MONITOR_WAIT or
404 // in SLEEPING or some other state.
405 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
406 java_lang_Thread::RUNNABLE);
407 }
408 os::start_thread(thread);
409 }
410 }
411
412 // Enqueue a VM_Operation to do the job for us - sometime later
413 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
414 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
415 VMThread::execute(vm_stop);
416 }
417
418
419 // Check if an external suspend request has completed (or has been
420 // cancelled). Returns true if the thread is externally suspended and
421 // false otherwise.
422 //
423 // The bits parameter returns information about the code path through
424 // the routine. Useful for debugging:
425 //
426 // set in is_ext_suspend_completed():
427 // 0x00000001 - routine was entered
428 // 0x00000010 - routine return false at end
429 // 0x00000100 - thread exited (return false)
430 // 0x00000200 - suspend request cancelled (return false)
431 // 0x00000400 - thread suspended (return true)
432 // 0x00001000 - thread is in a suspend equivalent state (return true)
433 // 0x00002000 - thread is native and walkable (return true)
434 // 0x00004000 - thread is native_trans and walkable (needed retry)
435 //
436 // set in wait_for_ext_suspend_completion():
437 // 0x00010000 - routine was entered
438 // 0x00020000 - suspend request cancelled before loop (return false)
439 // 0x00040000 - thread suspended before loop (return true)
440 // 0x00080000 - suspend request cancelled in loop (return false)
441 // 0x00100000 - thread suspended in loop (return true)
442 // 0x00200000 - suspend not completed during retry loop (return false)
443
444 // Helper class for tracing suspend wait debug bits.
445 //
446 // 0x00000100 indicates that the target thread exited before it could
447 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
448 // 0x00080000 each indicate a cancelled suspend request so they don't
449 // count as wait failures either.
450 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
451
452 class TraceSuspendDebugBits : public StackObj {
453 private:
454 JavaThread * jt;
455 bool is_wait;
456 bool called_by_wait; // meaningful when !is_wait
457 uint32_t * bits;
458
459 public:
460 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
461 uint32_t *_bits) {
462 jt = _jt;
463 is_wait = _is_wait;
464 called_by_wait = _called_by_wait;
465 bits = _bits;
466 }
467
468 ~TraceSuspendDebugBits() {
469 if (!is_wait) {
470 #if 1
471 // By default, don't trace bits for is_ext_suspend_completed() calls.
472 // That trace is very chatty.
473 return;
474 #else
475 if (!called_by_wait) {
476 // If tracing for is_ext_suspend_completed() is enabled, then only
477 // trace calls to it from wait_for_ext_suspend_completion()
478 return;
479 }
480 #endif
481 }
482
483 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
484 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
485 MutexLocker ml(Threads_lock); // needed for get_thread_name()
486 ResourceMark rm;
487
488 tty->print_cr(
489 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
490 jt->get_thread_name(), *bits);
491
492 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
493 }
494 }
495 }
496 };
497 #undef DEBUG_FALSE_BITS
498
499
500 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
501 uint32_t *bits) {
502 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
503
504 bool did_trans_retry = false; // only do thread_in_native_trans retry once
505 bool do_trans_retry; // flag to force the retry
506
507 *bits |= 0x00000001;
508
509 do {
510 do_trans_retry = false;
511
512 if (is_exiting()) {
513 // Thread is in the process of exiting. This is always checked
514 // first to reduce the risk of dereferencing a freed JavaThread.
515 *bits |= 0x00000100;
516 return false;
517 }
518
519 if (!is_external_suspend()) {
520 // Suspend request is cancelled. This is always checked before
521 // is_ext_suspended() to reduce the risk of a rogue resume
522 // confusing the thread that made the suspend request.
523 *bits |= 0x00000200;
524 return false;
525 }
526
527 if (is_ext_suspended()) {
528 // thread is suspended
529 *bits |= 0x00000400;
530 return true;
531 }
532
533 // Now that we no longer do hard suspends of threads running
534 // native code, the target thread can be changing thread state
535 // while we are in this routine:
536 //
537 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
538 //
539 // We save a copy of the thread state as observed at this moment
540 // and make our decision about suspend completeness based on the
541 // copy. This closes the race where the thread state is seen as
542 // _thread_in_native_trans in the if-thread_blocked check, but is
543 // seen as _thread_blocked in if-thread_in_native_trans check.
544 JavaThreadState save_state = thread_state();
545
546 if (save_state == _thread_blocked && is_suspend_equivalent()) {
547 // If the thread's state is _thread_blocked and this blocking
548 // condition is known to be equivalent to a suspend, then we can
549 // consider the thread to be externally suspended. This means that
550 // the code that sets _thread_blocked has been modified to do
551 // self-suspension if the blocking condition releases. We also
552 // used to check for CONDVAR_WAIT here, but that is now covered by
553 // the _thread_blocked with self-suspension check.
554 //
555 // Return true since we wouldn't be here unless there was still an
556 // external suspend request.
557 *bits |= 0x00001000;
558 return true;
559 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
560 // Threads running native code will self-suspend on native==>VM/Java
561 // transitions. If its stack is walkable (should always be the case
562 // unless this function is called before the actual java_suspend()
563 // call), then the wait is done.
564 *bits |= 0x00002000;
565 return true;
566 } else if (!called_by_wait && !did_trans_retry &&
567 save_state == _thread_in_native_trans &&
568 frame_anchor()->walkable()) {
569 // The thread is transitioning from thread_in_native to another
570 // thread state. check_safepoint_and_suspend_for_native_trans()
571 // will force the thread to self-suspend. If it hasn't gotten
572 // there yet we may have caught the thread in-between the native
573 // code check above and the self-suspend. Lucky us. If we were
574 // called by wait_for_ext_suspend_completion(), then it
575 // will be doing the retries so we don't have to.
576 //
577 // Since we use the saved thread state in the if-statement above,
578 // there is a chance that the thread has already transitioned to
579 // _thread_blocked by the time we get here. In that case, we will
580 // make a single unnecessary pass through the logic below. This
581 // doesn't hurt anything since we still do the trans retry.
582
583 *bits |= 0x00004000;
584
585 // Once the thread leaves thread_in_native_trans for another
586 // thread state, we break out of this retry loop. We shouldn't
587 // need this flag to prevent us from getting back here, but
588 // sometimes paranoia is good.
589 did_trans_retry = true;
590
591 // We wait for the thread to transition to a more usable state.
592 for (int i = 1; i <= SuspendRetryCount; i++) {
593 // We used to do an "os::yield_all(i)" call here with the intention
594 // that yielding would increase on each retry. However, the parameter
595 // is ignored on Linux which means the yield didn't scale up. Waiting
596 // on the SR_lock below provides a much more predictable scale up for
597 // the delay. It also provides a simple/direct point to check for any
598 // safepoint requests from the VMThread
599
600 // temporarily drops SR_lock while doing wait with safepoint check
601 // (if we're a JavaThread - the WatcherThread can also call this)
602 // and increase delay with each retry
603 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
604
605 // check the actual thread state instead of what we saved above
606 if (thread_state() != _thread_in_native_trans) {
607 // the thread has transitioned to another thread state so
608 // try all the checks (except this one) one more time.
609 do_trans_retry = true;
610 break;
611 }
612 } // end retry loop
613
614
615 }
616 } while (do_trans_retry);
617
618 *bits |= 0x00000010;
619 return false;
620 }
621
622 // Wait for an external suspend request to complete (or be cancelled).
623 // Returns true if the thread is externally suspended and false otherwise.
624 //
625 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
626 uint32_t *bits) {
627 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
628 false /* !called_by_wait */, bits);
629
630 // local flag copies to minimize SR_lock hold time
631 bool is_suspended;
632 bool pending;
633 uint32_t reset_bits;
634
635 // set a marker so is_ext_suspend_completed() knows we are the caller
636 *bits |= 0x00010000;
637
638 // We use reset_bits to reinitialize the bits value at the top of
639 // each retry loop. This allows the caller to make use of any
640 // unused bits for their own marking purposes.
641 reset_bits = *bits;
642
643 {
644 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
645 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
646 delay, bits);
647 pending = is_external_suspend();
648 }
649 // must release SR_lock to allow suspension to complete
650
651 if (!pending) {
652 // A cancelled suspend request is the only false return from
653 // is_ext_suspend_completed() that keeps us from entering the
654 // retry loop.
655 *bits |= 0x00020000;
656 return false;
657 }
658
659 if (is_suspended) {
660 *bits |= 0x00040000;
661 return true;
662 }
663
664 for (int i = 1; i <= retries; i++) {
665 *bits = reset_bits; // reinit to only track last retry
666
667 // We used to do an "os::yield_all(i)" call here with the intention
668 // that yielding would increase on each retry. However, the parameter
669 // is ignored on Linux which means the yield didn't scale up. Waiting
670 // on the SR_lock below provides a much more predictable scale up for
671 // the delay. It also provides a simple/direct point to check for any
672 // safepoint requests from the VMThread
673
674 {
675 MutexLocker ml(SR_lock());
676 // wait with safepoint check (if we're a JavaThread - the WatcherThread
677 // can also call this) and increase delay with each retry
678 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
679
680 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
681 delay, bits);
682
683 // It is possible for the external suspend request to be cancelled
684 // (by a resume) before the actual suspend operation is completed.
685 // Refresh our local copy to see if we still need to wait.
686 pending = is_external_suspend();
687 }
688
689 if (!pending) {
690 // A cancelled suspend request is the only false return from
691 // is_ext_suspend_completed() that keeps us from staying in the
692 // retry loop.
693 *bits |= 0x00080000;
694 return false;
695 }
696
697 if (is_suspended) {
698 *bits |= 0x00100000;
699 return true;
700 }
701 } // end retry loop
702
703 // thread did not suspend after all our retries
704 *bits |= 0x00200000;
705 return false;
706 }
707
708 #ifndef PRODUCT
709 void JavaThread::record_jump(address target, address instr, const char* file,
710 int line) {
711
712 // This should not need to be atomic as the only way for simultaneous
713 // updates is via interrupts. Even then this should be rare or non-existent
714 // and we don't care that much anyway.
715
716 int index = _jmp_ring_index;
717 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
718 _jmp_ring[index]._target = (intptr_t) target;
719 _jmp_ring[index]._instruction = (intptr_t) instr;
720 _jmp_ring[index]._file = file;
721 _jmp_ring[index]._line = line;
722 }
723 #endif // PRODUCT
724
725 // Called by flat profiler
726 // Callers have already called wait_for_ext_suspend_completion
727 // The assertion for that is currently too complex to put here:
728 bool JavaThread::profile_last_Java_frame(frame* _fr) {
729 bool gotframe = false;
730 // self suspension saves needed state.
731 if (has_last_Java_frame() && _anchor.walkable()) {
732 *_fr = pd_last_frame();
733 gotframe = true;
734 }
735 return gotframe;
736 }
737
738 void Thread::interrupt(Thread* thread) {
739 debug_only(check_for_dangling_thread_pointer(thread);)
740 os::interrupt(thread);
741 }
742
743 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
744 debug_only(check_for_dangling_thread_pointer(thread);)
745 // Note: If clear_interrupted==false, this simply fetches and
746 // returns the value of the field osthread()->interrupted().
747 return os::is_interrupted(thread, clear_interrupted);
748 }
749
750
751 // GC Support
752 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
753 jint thread_parity = _oops_do_parity;
754 if (thread_parity != strong_roots_parity) {
755 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
756 if (res == thread_parity) {
757 return true;
758 } else {
759 guarantee(res == strong_roots_parity, "Or else what?");
760 return false;
761 }
762 }
763 return false;
764 }
765
766 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
767 active_handles()->oops_do(f);
768 // Do oop for ThreadShadow
769 f->do_oop((oop*)&_pending_exception);
770 handle_area()->oops_do(f);
771 }
772
773 void Thread::nmethods_do(CodeBlobClosure* cf) {
774 // no nmethods in a generic thread...
775 }
776
777 void Thread::metadata_handles_do(void f(Metadata*)) {
778 // Only walk the Handles in Thread.
779 if (metadata_handles() != NULL) {
780 for (int i = 0; i< metadata_handles()->length(); i++) {
781 f(metadata_handles()->at(i));
782 }
783 }
784 }
785
786 void Thread::print_on(outputStream* st) const {
787 // get_priority assumes osthread initialized
788 if (osthread() != NULL) {
789 int os_prio;
790 if (os::get_native_priority(this, &os_prio) == OS_OK) {
791 st->print("os_prio=%d ", os_prio);
792 }
793 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
794 ext().print_on(st);
795 osthread()->print_on(st);
796 }
797 debug_only(if (WizardMode) print_owned_locks_on(st);)
798 }
799
800 // Thread::print_on_error() is called by fatal error handler. Don't use
801 // any lock or allocate memory.
802 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
803 if (is_VM_thread()) st->print("VMThread");
804 else if (is_Compiler_thread()) st->print("CompilerThread");
805 else if (is_Java_thread()) st->print("JavaThread");
806 else if (is_GC_task_thread()) st->print("GCTaskThread");
807 else if (is_Watcher_thread()) st->print("WatcherThread");
808 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
809 else st->print("Thread");
810
811 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
812 p2i(_stack_base - _stack_size), p2i(_stack_base));
813
814 if (osthread()) {
815 st->print(" [id=%d]", osthread()->thread_id());
816 }
817 }
818
819 #ifdef ASSERT
820 void Thread::print_owned_locks_on(outputStream* st) const {
821 Monitor *cur = _owned_locks;
822 if (cur == NULL) {
823 st->print(" (no locks) ");
824 } else {
825 st->print_cr(" Locks owned:");
826 while (cur) {
827 cur->print_on(st);
828 cur = cur->next();
829 }
830 }
831 }
832
833 static int ref_use_count = 0;
834
835 bool Thread::owns_locks_but_compiled_lock() const {
836 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
837 if (cur != Compile_lock) return true;
838 }
839 return false;
840 }
841
842
843 #endif
844
845 #ifndef PRODUCT
846
847 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
848 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
849 // no threads which allow_vm_block's are held
850 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
851 // Check if current thread is allowed to block at a safepoint
852 if (!(_allow_safepoint_count == 0)) {
853 fatal("Possible safepoint reached by thread that does not allow it");
854 }
855 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
856 fatal("LEAF method calling lock?");
857 }
858
859 #ifdef ASSERT
860 if (potential_vm_operation && is_Java_thread()
861 && !Universe::is_bootstrapping()) {
862 // Make sure we do not hold any locks that the VM thread also uses.
863 // This could potentially lead to deadlocks
864 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
865 // Threads_lock is special, since the safepoint synchronization will not start before this is
866 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
867 // since it is used to transfer control between JavaThreads and the VMThread
868 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
869 if ((cur->allow_vm_block() &&
870 cur != Threads_lock &&
871 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
872 cur != VMOperationRequest_lock &&
873 cur != VMOperationQueue_lock) ||
874 cur->rank() == Mutex::special) {
875 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
876 }
877 }
878 }
879
880 if (GCALotAtAllSafepoints) {
881 // We could enter a safepoint here and thus have a gc
882 InterfaceSupport::check_gc_alot();
883 }
884 #endif
885 }
886 #endif
887
888 bool Thread::is_in_stack(address adr) const {
889 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
890 address end = os::current_stack_pointer();
891 // Allow non Java threads to call this without stack_base
892 if (_stack_base == NULL) return true;
893 if (stack_base() >= adr && adr >= end) return true;
894
895 return false;
896 }
897
898
899 bool Thread::is_in_usable_stack(address adr) const {
900 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
901 size_t usable_stack_size = _stack_size - stack_guard_size;
902
903 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
904 }
905
906
907 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
908 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
909 // used for compilation in the future. If that change is made, the need for these methods
910 // should be revisited, and they should be removed if possible.
911
912 bool Thread::is_lock_owned(address adr) const {
913 return on_local_stack(adr);
914 }
915
916 bool Thread::set_as_starting_thread() {
917 // NOTE: this must be called inside the main thread.
918 return os::create_main_thread((JavaThread*)this);
919 }
920
921 static void initialize_class(Symbol* class_name, TRAPS) {
922 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
923 InstanceKlass::cast(klass)->initialize(CHECK);
924 }
925
926
927 // Creates the initial ThreadGroup
928 static Handle create_initial_thread_group(TRAPS) {
929 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
930 instanceKlassHandle klass (THREAD, k);
931
932 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
933 {
934 JavaValue result(T_VOID);
935 JavaCalls::call_special(&result,
936 system_instance,
937 klass,
938 vmSymbols::object_initializer_name(),
939 vmSymbols::void_method_signature(),
940 CHECK_NH);
941 }
942 Universe::set_system_thread_group(system_instance());
943
944 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
945 {
946 JavaValue result(T_VOID);
947 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
948 JavaCalls::call_special(&result,
949 main_instance,
950 klass,
951 vmSymbols::object_initializer_name(),
952 vmSymbols::threadgroup_string_void_signature(),
953 system_instance,
954 string,
955 CHECK_NH);
956 }
957 return main_instance;
958 }
959
960 // Creates the initial Thread
961 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
962 TRAPS) {
963 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
964 instanceKlassHandle klass (THREAD, k);
965 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
966
967 java_lang_Thread::set_thread(thread_oop(), thread);
968 java_lang_Thread::set_priority(thread_oop(), NormPriority);
969 thread->set_threadObj(thread_oop());
970
971 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
972
973 JavaValue result(T_VOID);
974 JavaCalls::call_special(&result, thread_oop,
975 klass,
976 vmSymbols::object_initializer_name(),
977 vmSymbols::threadgroup_string_void_signature(),
978 thread_group,
979 string,
980 CHECK_NULL);
981 return thread_oop();
982 }
983
984 static void call_initializeSystemClass(TRAPS) {
985 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
986 instanceKlassHandle klass (THREAD, k);
987
988 JavaValue result(T_VOID);
989 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
990 vmSymbols::void_method_signature(), CHECK);
991 }
992
993 char java_runtime_name[128] = "";
994 char java_runtime_version[128] = "";
995
996 // extract the JRE name from sun.misc.Version.java_runtime_name
997 static const char* get_java_runtime_name(TRAPS) {
998 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
999 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1000 fieldDescriptor fd;
1001 bool found = k != NULL &&
1002 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1003 vmSymbols::string_signature(), &fd);
1004 if (found) {
1005 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1006 if (name_oop == NULL) {
1007 return NULL;
1008 }
1009 const char* name = java_lang_String::as_utf8_string(name_oop,
1010 java_runtime_name,
1011 sizeof(java_runtime_name));
1012 return name;
1013 } else {
1014 return NULL;
1015 }
1016 }
1017
1018 // extract the JRE version from sun.misc.Version.java_runtime_version
1019 static const char* get_java_runtime_version(TRAPS) {
1020 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1021 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1022 fieldDescriptor fd;
1023 bool found = k != NULL &&
1024 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1025 vmSymbols::string_signature(), &fd);
1026 if (found) {
1027 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1028 if (name_oop == NULL) {
1029 return NULL;
1030 }
1031 const char* name = java_lang_String::as_utf8_string(name_oop,
1032 java_runtime_version,
1033 sizeof(java_runtime_version));
1034 return name;
1035 } else {
1036 return NULL;
1037 }
1038 }
1039
1040 // General purpose hook into Java code, run once when the VM is initialized.
1041 // The Java library method itself may be changed independently from the VM.
1042 static void call_postVMInitHook(TRAPS) {
1043 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1044 instanceKlassHandle klass (THREAD, k);
1045 if (klass.not_null()) {
1046 JavaValue result(T_VOID);
1047 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1048 vmSymbols::void_method_signature(),
1049 CHECK);
1050 }
1051 }
1052
1053 static void reset_vm_info_property(TRAPS) {
1054 // the vm info string
1055 ResourceMark rm(THREAD);
1056 const char *vm_info = VM_Version::vm_info_string();
1057
1058 // java.lang.System class
1059 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1060 instanceKlassHandle klass (THREAD, k);
1061
1062 // setProperty arguments
1063 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1064 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1065
1066 // return value
1067 JavaValue r(T_OBJECT);
1068
1069 // public static String setProperty(String key, String value);
1070 JavaCalls::call_static(&r,
1071 klass,
1072 vmSymbols::setProperty_name(),
1073 vmSymbols::string_string_string_signature(),
1074 key_str,
1075 value_str,
1076 CHECK);
1077 }
1078
1079
1080 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1081 bool daemon, TRAPS) {
1082 assert(thread_group.not_null(), "thread group should be specified");
1083 assert(threadObj() == NULL, "should only create Java thread object once");
1084
1085 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1086 instanceKlassHandle klass (THREAD, k);
1087 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1088
1089 java_lang_Thread::set_thread(thread_oop(), this);
1090 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1091 set_threadObj(thread_oop());
1092
1093 JavaValue result(T_VOID);
1094 if (thread_name != NULL) {
1095 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1096 // Thread gets assigned specified name and null target
1097 JavaCalls::call_special(&result,
1098 thread_oop,
1099 klass,
1100 vmSymbols::object_initializer_name(),
1101 vmSymbols::threadgroup_string_void_signature(),
1102 thread_group, // Argument 1
1103 name, // Argument 2
1104 THREAD);
1105 } else {
1106 // Thread gets assigned name "Thread-nnn" and null target
1107 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1108 JavaCalls::call_special(&result,
1109 thread_oop,
1110 klass,
1111 vmSymbols::object_initializer_name(),
1112 vmSymbols::threadgroup_runnable_void_signature(),
1113 thread_group, // Argument 1
1114 Handle(), // Argument 2
1115 THREAD);
1116 }
1117
1118
1119 if (daemon) {
1120 java_lang_Thread::set_daemon(thread_oop());
1121 }
1122
1123 if (HAS_PENDING_EXCEPTION) {
1124 return;
1125 }
1126
1127 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1128 Handle threadObj(THREAD, this->threadObj());
1129
1130 JavaCalls::call_special(&result,
1131 thread_group,
1132 group,
1133 vmSymbols::add_method_name(),
1134 vmSymbols::thread_void_signature(),
1135 threadObj, // Arg 1
1136 THREAD);
1137 }
1138
1139 // NamedThread -- non-JavaThread subclasses with multiple
1140 // uniquely named instances should derive from this.
1141 NamedThread::NamedThread() : Thread() {
1142 _name = NULL;
1143 _processed_thread = NULL;
1144 _gc_id = GCId::undefined();
1145 }
1146
1147 NamedThread::~NamedThread() {
1148 if (_name != NULL) {
1149 FREE_C_HEAP_ARRAY(char, _name);
1150 _name = NULL;
1151 }
1152 }
1153
1154 void NamedThread::set_name(const char* format, ...) {
1155 guarantee(_name == NULL, "Only get to set name once.");
1156 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1157 guarantee(_name != NULL, "alloc failure");
1158 va_list ap;
1159 va_start(ap, format);
1160 jio_vsnprintf(_name, max_name_len, format, ap);
1161 va_end(ap);
1162 }
1163
1164 void NamedThread::initialize_named_thread() {
1165 set_native_thread_name(name());
1166 }
1167
1168 void NamedThread::print_on(outputStream* st) const {
1169 st->print("\"%s\" ", name());
1170 Thread::print_on(st);
1171 st->cr();
1172 }
1173
1174
1175 // ======= WatcherThread ========
1176
1177 // The watcher thread exists to simulate timer interrupts. It should
1178 // be replaced by an abstraction over whatever native support for
1179 // timer interrupts exists on the platform.
1180
1181 WatcherThread* WatcherThread::_watcher_thread = NULL;
1182 bool WatcherThread::_startable = false;
1183 volatile bool WatcherThread::_should_terminate = false;
1184
1185 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1186 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1187 if (os::create_thread(this, os::watcher_thread)) {
1188 _watcher_thread = this;
1189
1190 // Set the watcher thread to the highest OS priority which should not be
1191 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1192 // is created. The only normal thread using this priority is the reference
1193 // handler thread, which runs for very short intervals only.
1194 // If the VMThread's priority is not lower than the WatcherThread profiling
1195 // will be inaccurate.
1196 os::set_priority(this, MaxPriority);
1197 if (!DisableStartThread) {
1198 os::start_thread(this);
1199 }
1200 }
1201 }
1202
1203 int WatcherThread::sleep() const {
1204 // The WatcherThread does not participate in the safepoint protocol
1205 // for the PeriodicTask_lock because it is not a JavaThread.
1206 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1207
1208 if (_should_terminate) {
1209 // check for termination before we do any housekeeping or wait
1210 return 0; // we did not sleep.
1211 }
1212
1213 // remaining will be zero if there are no tasks,
1214 // causing the WatcherThread to sleep until a task is
1215 // enrolled
1216 int remaining = PeriodicTask::time_to_wait();
1217 int time_slept = 0;
1218
1219 // we expect this to timeout - we only ever get unparked when
1220 // we should terminate or when a new task has been enrolled
1221 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1222
1223 jlong time_before_loop = os::javaTimeNanos();
1224
1225 while (true) {
1226 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1227 remaining);
1228 jlong now = os::javaTimeNanos();
1229
1230 if (remaining == 0) {
1231 // if we didn't have any tasks we could have waited for a long time
1232 // consider the time_slept zero and reset time_before_loop
1233 time_slept = 0;
1234 time_before_loop = now;
1235 } else {
1236 // need to recalculate since we might have new tasks in _tasks
1237 time_slept = (int) ((now - time_before_loop) / 1000000);
1238 }
1239
1240 // Change to task list or spurious wakeup of some kind
1241 if (timedout || _should_terminate) {
1242 break;
1243 }
1244
1245 remaining = PeriodicTask::time_to_wait();
1246 if (remaining == 0) {
1247 // Last task was just disenrolled so loop around and wait until
1248 // another task gets enrolled
1249 continue;
1250 }
1251
1252 remaining -= time_slept;
1253 if (remaining <= 0) {
1254 break;
1255 }
1256 }
1257
1258 return time_slept;
1259 }
1260
1261 void WatcherThread::run() {
1262 assert(this == watcher_thread(), "just checking");
1263
1264 this->record_stack_base_and_size();
1265 this->set_native_thread_name(this->name());
1266 this->set_active_handles(JNIHandleBlock::allocate_block());
1267 while (true) {
1268 assert(watcher_thread() == Thread::current(), "thread consistency check");
1269 assert(watcher_thread() == this, "thread consistency check");
1270
1271 // Calculate how long it'll be until the next PeriodicTask work
1272 // should be done, and sleep that amount of time.
1273 int time_waited = sleep();
1274
1275 if (is_error_reported()) {
1276 // A fatal error has happened, the error handler(VMError::report_and_die)
1277 // should abort JVM after creating an error log file. However in some
1278 // rare cases, the error handler itself might deadlock. Here we try to
1279 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1280 //
1281 // This code is in WatcherThread because WatcherThread wakes up
1282 // periodically so the fatal error handler doesn't need to do anything;
1283 // also because the WatcherThread is less likely to crash than other
1284 // threads.
1285
1286 for (;;) {
1287 if (!ShowMessageBoxOnError
1288 && (OnError == NULL || OnError[0] == '\0')
1289 && Arguments::abort_hook() == NULL) {
1290 os::sleep(this, ErrorLogTimeout * 60 * 1000, false);
1291 fdStream err(defaultStream::output_fd());
1292 err.print_raw_cr("# [ timer expired, abort... ]");
1293 // skip atexit/vm_exit/vm_abort hooks
1294 os::die();
1295 }
1296
1297 // Wake up 5 seconds later, the fatal handler may reset OnError or
1298 // ShowMessageBoxOnError when it is ready to abort.
1299 os::sleep(this, 5 * 1000, false);
1300 }
1301 }
1302
1303 if (_should_terminate) {
1304 // check for termination before posting the next tick
1305 break;
1306 }
1307
1308 PeriodicTask::real_time_tick(time_waited);
1309 }
1310
1311 // Signal that it is terminated
1312 {
1313 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1314 _watcher_thread = NULL;
1315 Terminator_lock->notify();
1316 }
1317 }
1318
1319 void WatcherThread::start() {
1320 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1321
1322 if (watcher_thread() == NULL && _startable) {
1323 _should_terminate = false;
1324 // Create the single instance of WatcherThread
1325 new WatcherThread();
1326 }
1327 }
1328
1329 void WatcherThread::make_startable() {
1330 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1331 _startable = true;
1332 }
1333
1334 void WatcherThread::stop() {
1335 {
1336 // Follow normal safepoint aware lock enter protocol since the
1337 // WatcherThread is stopped by another JavaThread.
1338 MutexLocker ml(PeriodicTask_lock);
1339 _should_terminate = true;
1340
1341 WatcherThread* watcher = watcher_thread();
1342 if (watcher != NULL) {
1343 // unpark the WatcherThread so it can see that it should terminate
1344 watcher->unpark();
1345 }
1346 }
1347
1348 MutexLocker mu(Terminator_lock);
1349
1350 while (watcher_thread() != NULL) {
1351 // This wait should make safepoint checks, wait without a timeout,
1352 // and wait as a suspend-equivalent condition.
1353 //
1354 // Note: If the FlatProfiler is running, then this thread is waiting
1355 // for the WatcherThread to terminate and the WatcherThread, via the
1356 // FlatProfiler task, is waiting for the external suspend request on
1357 // this thread to complete. wait_for_ext_suspend_completion() will
1358 // eventually timeout, but that takes time. Making this wait a
1359 // suspend-equivalent condition solves that timeout problem.
1360 //
1361 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1362 Mutex::_as_suspend_equivalent_flag);
1363 }
1364 }
1365
1366 void WatcherThread::unpark() {
1367 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1368 PeriodicTask_lock->notify();
1369 }
1370
1371 void WatcherThread::print_on(outputStream* st) const {
1372 st->print("\"%s\" ", name());
1373 Thread::print_on(st);
1374 st->cr();
1375 }
1376
1377 // ======= JavaThread ========
1378
1379 #if INCLUDE_JVMCI
1380
1381 jlong* JavaThread::_jvmci_old_thread_counters;
1382
1383 bool jvmci_counters_include(JavaThread* thread) {
1384 oop threadObj = thread->threadObj();
1385 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1386 }
1387
1388 void JavaThread::collect_counters(typeArrayOop array) {
1389 if (JVMCICounterSize > 0) {
1390 MutexLocker tl(Threads_lock);
1391 for (int i = 0; i < array->length(); i++) {
1392 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1393 }
1394 for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) {
1395 if (jvmci_counters_include(tp)) {
1396 for (int i = 0; i < array->length(); i++) {
1397 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1398 }
1399 }
1400 }
1401 }
1402 }
1403
1404 #endif // INCLUDE_JVMCI
1405
1406 // A JavaThread is a normal Java thread
1407
1408 void JavaThread::initialize() {
1409 // Initialize fields
1410
1411 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1412 set_claimed_par_id(UINT_MAX);
1413
1414 set_saved_exception_pc(NULL);
1415 set_threadObj(NULL);
1416 _anchor.clear();
1417 set_entry_point(NULL);
1418 set_jni_functions(jni_functions());
1419 set_callee_target(NULL);
1420 set_vm_result(NULL);
1421 set_vm_result_2(NULL);
1422 set_vframe_array_head(NULL);
1423 set_vframe_array_last(NULL);
1424 set_deferred_locals(NULL);
1425 set_deopt_mark(NULL);
1426 set_deopt_nmethod(NULL);
1427 clear_must_deopt_id();
1428 set_monitor_chunks(NULL);
1429 set_next(NULL);
1430 set_thread_state(_thread_new);
1431 _terminated = _not_terminated;
1432 _privileged_stack_top = NULL;
1433 _array_for_gc = NULL;
1434 _suspend_equivalent = false;
1435 _in_deopt_handler = 0;
1436 _doing_unsafe_access = false;
1437 _stack_guard_state = stack_guard_unused;
1438 #if INCLUDE_JVMCI
1439 _pending_monitorenter = false;
1440 _pending_deoptimization = -1;
1441 _pending_failed_speculation = NULL;
1442 _pending_transfer_to_interpreter = false;
1443 _jvmci._alternate_call_target = NULL;
1444 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1445 if (JVMCICounterSize > 0) {
1446 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1447 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1448 } else {
1449 _jvmci_counters = NULL;
1450 }
1451 #endif // INCLUDE_JVMCI
1452 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1453 _exception_pc = 0;
1454 _exception_handler_pc = 0;
1455 _is_method_handle_return = 0;
1456 _jvmti_thread_state= NULL;
1457 _should_post_on_exceptions_flag = JNI_FALSE;
1458 _jvmti_get_loaded_classes_closure = NULL;
1459 _interp_only_mode = 0;
1460 _special_runtime_exit_condition = _no_async_condition;
1461 _pending_async_exception = NULL;
1462 _thread_stat = NULL;
1463 _thread_stat = new ThreadStatistics();
1464 _blocked_on_compilation = false;
1465 _jni_active_critical = 0;
1466 _pending_jni_exception_check_fn = NULL;
1467 _do_not_unlock_if_synchronized = false;
1468 _cached_monitor_info = NULL;
1469 _parker = Parker::Allocate(this);
1470
1471 #ifndef PRODUCT
1472 _jmp_ring_index = 0;
1473 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1474 record_jump(NULL, NULL, NULL, 0);
1475 }
1476 #endif // PRODUCT
1477
1478 set_thread_profiler(NULL);
1479 if (FlatProfiler::is_active()) {
1480 // This is where we would decide to either give each thread it's own profiler
1481 // or use one global one from FlatProfiler,
1482 // or up to some count of the number of profiled threads, etc.
1483 ThreadProfiler* pp = new ThreadProfiler();
1484 pp->engage();
1485 set_thread_profiler(pp);
1486 }
1487
1488 // Setup safepoint state info for this thread
1489 ThreadSafepointState::create(this);
1490
1491 debug_only(_java_call_counter = 0);
1492
1493 // JVMTI PopFrame support
1494 _popframe_condition = popframe_inactive;
1495 _popframe_preserved_args = NULL;
1496 _popframe_preserved_args_size = 0;
1497 _frames_to_pop_failed_realloc = 0;
1498
1499 pd_initialize();
1500 }
1501
1502 #if INCLUDE_ALL_GCS
1503 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1504 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1505 #endif // INCLUDE_ALL_GCS
1506
1507 JavaThread::JavaThread(bool is_attaching_via_jni) :
1508 Thread()
1509 #if INCLUDE_ALL_GCS
1510 , _satb_mark_queue(&_satb_mark_queue_set),
1511 _dirty_card_queue(&_dirty_card_queue_set)
1512 #endif // INCLUDE_ALL_GCS
1513 {
1514 initialize();
1515 if (is_attaching_via_jni) {
1516 _jni_attach_state = _attaching_via_jni;
1517 } else {
1518 _jni_attach_state = _not_attaching_via_jni;
1519 }
1520 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1521 }
1522
1523 bool JavaThread::reguard_stack(address cur_sp) {
1524 if (_stack_guard_state != stack_guard_yellow_disabled) {
1525 return true; // Stack already guarded or guard pages not needed.
1526 }
1527
1528 if (register_stack_overflow()) {
1529 // For those architectures which have separate register and
1530 // memory stacks, we must check the register stack to see if
1531 // it has overflowed.
1532 return false;
1533 }
1534
1535 // Java code never executes within the yellow zone: the latter is only
1536 // there to provoke an exception during stack banging. If java code
1537 // is executing there, either StackShadowPages should be larger, or
1538 // some exception code in c1, c2 or the interpreter isn't unwinding
1539 // when it should.
1540 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1541
1542 enable_stack_yellow_zone();
1543 return true;
1544 }
1545
1546 bool JavaThread::reguard_stack(void) {
1547 return reguard_stack(os::current_stack_pointer());
1548 }
1549
1550
1551 void JavaThread::block_if_vm_exited() {
1552 if (_terminated == _vm_exited) {
1553 // _vm_exited is set at safepoint, and Threads_lock is never released
1554 // we will block here forever
1555 Threads_lock->lock_without_safepoint_check();
1556 ShouldNotReachHere();
1557 }
1558 }
1559
1560
1561 // Remove this ifdef when C1 is ported to the compiler interface.
1562 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1563 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1564
1565 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1566 Thread()
1567 #if INCLUDE_ALL_GCS
1568 , _satb_mark_queue(&_satb_mark_queue_set),
1569 _dirty_card_queue(&_dirty_card_queue_set)
1570 #endif // INCLUDE_ALL_GCS
1571 {
1572 initialize();
1573 _jni_attach_state = _not_attaching_via_jni;
1574 set_entry_point(entry_point);
1575 // Create the native thread itself.
1576 // %note runtime_23
1577 os::ThreadType thr_type = os::java_thread;
1578 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1579 os::java_thread;
1580 os::create_thread(this, thr_type, stack_sz);
1581 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1582 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1583 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1584 // the exception consists of creating the exception object & initializing it, initialization
1585 // will leave the VM via a JavaCall and then all locks must be unlocked).
1586 //
1587 // The thread is still suspended when we reach here. Thread must be explicit started
1588 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1589 // by calling Threads:add. The reason why this is not done here, is because the thread
1590 // object must be fully initialized (take a look at JVM_Start)
1591 }
1592
1593 JavaThread::~JavaThread() {
1594
1595 // JSR166 -- return the parker to the free list
1596 Parker::Release(_parker);
1597 _parker = NULL;
1598
1599 // Free any remaining previous UnrollBlock
1600 vframeArray* old_array = vframe_array_last();
1601
1602 if (old_array != NULL) {
1603 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1604 old_array->set_unroll_block(NULL);
1605 delete old_info;
1606 delete old_array;
1607 }
1608
1609 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1610 if (deferred != NULL) {
1611 // This can only happen if thread is destroyed before deoptimization occurs.
1612 assert(deferred->length() != 0, "empty array!");
1613 do {
1614 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1615 deferred->remove_at(0);
1616 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1617 delete dlv;
1618 } while (deferred->length() != 0);
1619 delete deferred;
1620 }
1621
1622 // All Java related clean up happens in exit
1623 ThreadSafepointState::destroy(this);
1624 if (_thread_profiler != NULL) delete _thread_profiler;
1625 if (_thread_stat != NULL) delete _thread_stat;
1626
1627 #if INCLUDE_JVMCI
1628 if (JVMCICounterSize > 0) {
1629 if (jvmci_counters_include(this)) {
1630 for (int i = 0; i < JVMCICounterSize; i++) {
1631 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1632 }
1633 }
1634 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1635 }
1636 #endif // INCLUDE_JVMCI
1637 }
1638
1639
1640 // The first routine called by a new Java thread
1641 void JavaThread::run() {
1642 // initialize thread-local alloc buffer related fields
1643 this->initialize_tlab();
1644
1645 // used to test validity of stack trace backs
1646 this->record_base_of_stack_pointer();
1647
1648 // Record real stack base and size.
1649 this->record_stack_base_and_size();
1650
1651 this->create_stack_guard_pages();
1652
1653 this->cache_global_variables();
1654
1655 // Thread is now sufficient initialized to be handled by the safepoint code as being
1656 // in the VM. Change thread state from _thread_new to _thread_in_vm
1657 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1658
1659 assert(JavaThread::current() == this, "sanity check");
1660 assert(!Thread::current()->owns_locks(), "sanity check");
1661
1662 DTRACE_THREAD_PROBE(start, this);
1663
1664 // This operation might block. We call that after all safepoint checks for a new thread has
1665 // been completed.
1666 this->set_active_handles(JNIHandleBlock::allocate_block());
1667
1668 if (JvmtiExport::should_post_thread_life()) {
1669 JvmtiExport::post_thread_start(this);
1670 }
1671
1672 EventThreadStart event;
1673 if (event.should_commit()) {
1674 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1675 event.commit();
1676 }
1677
1678 // We call another function to do the rest so we are sure that the stack addresses used
1679 // from there will be lower than the stack base just computed
1680 thread_main_inner();
1681
1682 // Note, thread is no longer valid at this point!
1683 }
1684
1685
1686 void JavaThread::thread_main_inner() {
1687 assert(JavaThread::current() == this, "sanity check");
1688 assert(this->threadObj() != NULL, "just checking");
1689
1690 // Execute thread entry point unless this thread has a pending exception
1691 // or has been stopped before starting.
1692 // Note: Due to JVM_StopThread we can have pending exceptions already!
1693 if (!this->has_pending_exception() &&
1694 !java_lang_Thread::is_stillborn(this->threadObj())) {
1695 {
1696 ResourceMark rm(this);
1697 this->set_native_thread_name(this->get_thread_name());
1698 }
1699 HandleMark hm(this);
1700 this->entry_point()(this, this);
1701 }
1702
1703 DTRACE_THREAD_PROBE(stop, this);
1704
1705 this->exit(false);
1706 delete this;
1707 }
1708
1709
1710 static void ensure_join(JavaThread* thread) {
1711 // We do not need to grap the Threads_lock, since we are operating on ourself.
1712 Handle threadObj(thread, thread->threadObj());
1713 assert(threadObj.not_null(), "java thread object must exist");
1714 ObjectLocker lock(threadObj, thread);
1715 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1716 thread->clear_pending_exception();
1717 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1718 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1719 // Clear the native thread instance - this makes isAlive return false and allows the join()
1720 // to complete once we've done the notify_all below
1721 java_lang_Thread::set_thread(threadObj(), NULL);
1722 lock.notify_all(thread);
1723 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1724 thread->clear_pending_exception();
1725 }
1726
1727
1728 // For any new cleanup additions, please check to see if they need to be applied to
1729 // cleanup_failed_attach_current_thread as well.
1730 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1731 assert(this == JavaThread::current(), "thread consistency check");
1732
1733 HandleMark hm(this);
1734 Handle uncaught_exception(this, this->pending_exception());
1735 this->clear_pending_exception();
1736 Handle threadObj(this, this->threadObj());
1737 assert(threadObj.not_null(), "Java thread object should be created");
1738
1739 if (get_thread_profiler() != NULL) {
1740 get_thread_profiler()->disengage();
1741 ResourceMark rm;
1742 get_thread_profiler()->print(get_thread_name());
1743 }
1744
1745
1746 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1747 {
1748 EXCEPTION_MARK;
1749
1750 CLEAR_PENDING_EXCEPTION;
1751 }
1752 if (!destroy_vm) {
1753 if (uncaught_exception.not_null()) {
1754 EXCEPTION_MARK;
1755 // Call method Thread.dispatchUncaughtException().
1756 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1757 JavaValue result(T_VOID);
1758 JavaCalls::call_virtual(&result,
1759 threadObj, thread_klass,
1760 vmSymbols::dispatchUncaughtException_name(),
1761 vmSymbols::throwable_void_signature(),
1762 uncaught_exception,
1763 THREAD);
1764 if (HAS_PENDING_EXCEPTION) {
1765 ResourceMark rm(this);
1766 jio_fprintf(defaultStream::error_stream(),
1767 "\nException: %s thrown from the UncaughtExceptionHandler"
1768 " in thread \"%s\"\n",
1769 pending_exception()->klass()->external_name(),
1770 get_thread_name());
1771 CLEAR_PENDING_EXCEPTION;
1772 }
1773 }
1774
1775 // Called before the java thread exit since we want to read info
1776 // from java_lang_Thread object
1777 EventThreadEnd event;
1778 if (event.should_commit()) {
1779 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1780 event.commit();
1781 }
1782
1783 // Call after last event on thread
1784 EVENT_THREAD_EXIT(this);
1785
1786 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1787 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1788 // is deprecated anyhow.
1789 if (!is_Compiler_thread()) {
1790 int count = 3;
1791 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1792 EXCEPTION_MARK;
1793 JavaValue result(T_VOID);
1794 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1795 JavaCalls::call_virtual(&result,
1796 threadObj, thread_klass,
1797 vmSymbols::exit_method_name(),
1798 vmSymbols::void_method_signature(),
1799 THREAD);
1800 CLEAR_PENDING_EXCEPTION;
1801 }
1802 }
1803 // notify JVMTI
1804 if (JvmtiExport::should_post_thread_life()) {
1805 JvmtiExport::post_thread_end(this);
1806 }
1807
1808 // We have notified the agents that we are exiting, before we go on,
1809 // we must check for a pending external suspend request and honor it
1810 // in order to not surprise the thread that made the suspend request.
1811 while (true) {
1812 {
1813 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1814 if (!is_external_suspend()) {
1815 set_terminated(_thread_exiting);
1816 ThreadService::current_thread_exiting(this);
1817 break;
1818 }
1819 // Implied else:
1820 // Things get a little tricky here. We have a pending external
1821 // suspend request, but we are holding the SR_lock so we
1822 // can't just self-suspend. So we temporarily drop the lock
1823 // and then self-suspend.
1824 }
1825
1826 ThreadBlockInVM tbivm(this);
1827 java_suspend_self();
1828
1829 // We're done with this suspend request, but we have to loop around
1830 // and check again. Eventually we will get SR_lock without a pending
1831 // external suspend request and will be able to mark ourselves as
1832 // exiting.
1833 }
1834 // no more external suspends are allowed at this point
1835 } else {
1836 // before_exit() has already posted JVMTI THREAD_END events
1837 }
1838
1839 // Notify waiters on thread object. This has to be done after exit() is called
1840 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1841 // group should have the destroyed bit set before waiters are notified).
1842 ensure_join(this);
1843 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1844
1845 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1846 // held by this thread must be released. The spec does not distinguish
1847 // between JNI-acquired and regular Java monitors. We can only see
1848 // regular Java monitors here if monitor enter-exit matching is broken.
1849 //
1850 // Optionally release any monitors for regular JavaThread exits. This
1851 // is provided as a work around for any bugs in monitor enter-exit
1852 // matching. This can be expensive so it is not enabled by default.
1853 //
1854 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1855 // ObjectSynchronizer::release_monitors_owned_by_thread().
1856 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
1857 // Sanity check even though JNI DetachCurrentThread() would have
1858 // returned JNI_ERR if there was a Java frame. JavaThread exit
1859 // should be done executing Java code by the time we get here.
1860 assert(!this->has_last_Java_frame(),
1861 "should not have a Java frame when detaching or exiting");
1862 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1863 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1864 }
1865
1866 // These things needs to be done while we are still a Java Thread. Make sure that thread
1867 // is in a consistent state, in case GC happens
1868 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1869
1870 if (active_handles() != NULL) {
1871 JNIHandleBlock* block = active_handles();
1872 set_active_handles(NULL);
1873 JNIHandleBlock::release_block(block);
1874 }
1875
1876 if (free_handle_block() != NULL) {
1877 JNIHandleBlock* block = free_handle_block();
1878 set_free_handle_block(NULL);
1879 JNIHandleBlock::release_block(block);
1880 }
1881
1882 // These have to be removed while this is still a valid thread.
1883 remove_stack_guard_pages();
1884
1885 if (UseTLAB) {
1886 tlab().make_parsable(true); // retire TLAB
1887 }
1888
1889 if (JvmtiEnv::environments_might_exist()) {
1890 JvmtiExport::cleanup_thread(this);
1891 }
1892
1893 // We must flush any deferred card marks before removing a thread from
1894 // the list of active threads.
1895 Universe::heap()->flush_deferred_store_barrier(this);
1896 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1897
1898 #if INCLUDE_ALL_GCS
1899 // We must flush the G1-related buffers before removing a thread
1900 // from the list of active threads. We must do this after any deferred
1901 // card marks have been flushed (above) so that any entries that are
1902 // added to the thread's dirty card queue as a result are not lost.
1903 if (UseG1GC) {
1904 flush_barrier_queues();
1905 }
1906 #endif // INCLUDE_ALL_GCS
1907
1908 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1909 Threads::remove(this);
1910 }
1911
1912 #if INCLUDE_ALL_GCS
1913 // Flush G1-related queues.
1914 void JavaThread::flush_barrier_queues() {
1915 satb_mark_queue().flush();
1916 dirty_card_queue().flush();
1917 }
1918
1919 void JavaThread::initialize_queues() {
1920 assert(!SafepointSynchronize::is_at_safepoint(),
1921 "we should not be at a safepoint");
1922
1923 ObjPtrQueue& satb_queue = satb_mark_queue();
1924 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1925 // The SATB queue should have been constructed with its active
1926 // field set to false.
1927 assert(!satb_queue.is_active(), "SATB queue should not be active");
1928 assert(satb_queue.is_empty(), "SATB queue should be empty");
1929 // If we are creating the thread during a marking cycle, we should
1930 // set the active field of the SATB queue to true.
1931 if (satb_queue_set.is_active()) {
1932 satb_queue.set_active(true);
1933 }
1934
1935 DirtyCardQueue& dirty_queue = dirty_card_queue();
1936 // The dirty card queue should have been constructed with its
1937 // active field set to true.
1938 assert(dirty_queue.is_active(), "dirty card queue should be active");
1939 }
1940 #endif // INCLUDE_ALL_GCS
1941
1942 void JavaThread::cleanup_failed_attach_current_thread() {
1943 if (get_thread_profiler() != NULL) {
1944 get_thread_profiler()->disengage();
1945 ResourceMark rm;
1946 get_thread_profiler()->print(get_thread_name());
1947 }
1948
1949 if (active_handles() != NULL) {
1950 JNIHandleBlock* block = active_handles();
1951 set_active_handles(NULL);
1952 JNIHandleBlock::release_block(block);
1953 }
1954
1955 if (free_handle_block() != NULL) {
1956 JNIHandleBlock* block = free_handle_block();
1957 set_free_handle_block(NULL);
1958 JNIHandleBlock::release_block(block);
1959 }
1960
1961 // These have to be removed while this is still a valid thread.
1962 remove_stack_guard_pages();
1963
1964 if (UseTLAB) {
1965 tlab().make_parsable(true); // retire TLAB, if any
1966 }
1967
1968 #if INCLUDE_ALL_GCS
1969 if (UseG1GC) {
1970 flush_barrier_queues();
1971 }
1972 #endif // INCLUDE_ALL_GCS
1973
1974 Threads::remove(this);
1975 delete this;
1976 }
1977
1978
1979
1980
1981 JavaThread* JavaThread::active() {
1982 Thread* thread = Thread::current();
1983 assert(thread != NULL, "just checking");
1984 if (thread->is_Java_thread()) {
1985 return (JavaThread*) thread;
1986 } else {
1987 assert(thread->is_VM_thread(), "this must be a vm thread");
1988 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1989 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1990 assert(ret->is_Java_thread(), "must be a Java thread");
1991 return ret;
1992 }
1993 }
1994
1995 bool JavaThread::is_lock_owned(address adr) const {
1996 if (Thread::is_lock_owned(adr)) return true;
1997
1998 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1999 if (chunk->contains(adr)) return true;
2000 }
2001
2002 return false;
2003 }
2004
2005
2006 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2007 chunk->set_next(monitor_chunks());
2008 set_monitor_chunks(chunk);
2009 }
2010
2011 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2012 guarantee(monitor_chunks() != NULL, "must be non empty");
2013 if (monitor_chunks() == chunk) {
2014 set_monitor_chunks(chunk->next());
2015 } else {
2016 MonitorChunk* prev = monitor_chunks();
2017 while (prev->next() != chunk) prev = prev->next();
2018 prev->set_next(chunk->next());
2019 }
2020 }
2021
2022 // JVM support.
2023
2024 // Note: this function shouldn't block if it's called in
2025 // _thread_in_native_trans state (such as from
2026 // check_special_condition_for_native_trans()).
2027 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2028
2029 if (has_last_Java_frame() && has_async_condition()) {
2030 // If we are at a polling page safepoint (not a poll return)
2031 // then we must defer async exception because live registers
2032 // will be clobbered by the exception path. Poll return is
2033 // ok because the call we a returning from already collides
2034 // with exception handling registers and so there is no issue.
2035 // (The exception handling path kills call result registers but
2036 // this is ok since the exception kills the result anyway).
2037
2038 if (is_at_poll_safepoint()) {
2039 // if the code we are returning to has deoptimized we must defer
2040 // the exception otherwise live registers get clobbered on the
2041 // exception path before deoptimization is able to retrieve them.
2042 //
2043 RegisterMap map(this, false);
2044 frame caller_fr = last_frame().sender(&map);
2045 assert(caller_fr.is_compiled_frame(), "what?");
2046 if (caller_fr.is_deoptimized_frame()) {
2047 if (TraceExceptions) {
2048 ResourceMark rm;
2049 tty->print_cr("deferred async exception at compiled safepoint");
2050 }
2051 return;
2052 }
2053 }
2054 }
2055
2056 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2057 if (condition == _no_async_condition) {
2058 // Conditions have changed since has_special_runtime_exit_condition()
2059 // was called:
2060 // - if we were here only because of an external suspend request,
2061 // then that was taken care of above (or cancelled) so we are done
2062 // - if we were here because of another async request, then it has
2063 // been cleared between the has_special_runtime_exit_condition()
2064 // and now so again we are done
2065 return;
2066 }
2067
2068 // Check for pending async. exception
2069 if (_pending_async_exception != NULL) {
2070 // Only overwrite an already pending exception, if it is not a threadDeath.
2071 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2072
2073 // We cannot call Exceptions::_throw(...) here because we cannot block
2074 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2075
2076 if (TraceExceptions) {
2077 ResourceMark rm;
2078 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2079 if (has_last_Java_frame()) {
2080 frame f = last_frame();
2081 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2082 }
2083 tty->print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2084 }
2085 _pending_async_exception = NULL;
2086 clear_has_async_exception();
2087 }
2088 }
2089
2090 if (check_unsafe_error &&
2091 condition == _async_unsafe_access_error && !has_pending_exception()) {
2092 condition = _no_async_condition; // done
2093 switch (thread_state()) {
2094 case _thread_in_vm: {
2095 JavaThread* THREAD = this;
2096 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2097 }
2098 case _thread_in_native: {
2099 ThreadInVMfromNative tiv(this);
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_Java: {
2104 ThreadInVMfromJava tiv(this);
2105 JavaThread* THREAD = this;
2106 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2107 }
2108 default:
2109 ShouldNotReachHere();
2110 }
2111 }
2112
2113 assert(condition == _no_async_condition || has_pending_exception() ||
2114 (!check_unsafe_error && condition == _async_unsafe_access_error),
2115 "must have handled the async condition, if no exception");
2116 }
2117
2118 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2119 //
2120 // Check for pending external suspend. Internal suspend requests do
2121 // not use handle_special_runtime_exit_condition().
2122 // If JNIEnv proxies are allowed, don't self-suspend if the target
2123 // thread is not the current thread. In older versions of jdbx, jdbx
2124 // threads could call into the VM with another thread's JNIEnv so we
2125 // can be here operating on behalf of a suspended thread (4432884).
2126 bool do_self_suspend = is_external_suspend_with_lock();
2127 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2128 //
2129 // Because thread is external suspended the safepoint code will count
2130 // thread as at a safepoint. This can be odd because we can be here
2131 // as _thread_in_Java which would normally transition to _thread_blocked
2132 // at a safepoint. We would like to mark the thread as _thread_blocked
2133 // before calling java_suspend_self like all other callers of it but
2134 // we must then observe proper safepoint protocol. (We can't leave
2135 // _thread_blocked with a safepoint in progress). However we can be
2136 // here as _thread_in_native_trans so we can't use a normal transition
2137 // constructor/destructor pair because they assert on that type of
2138 // transition. We could do something like:
2139 //
2140 // JavaThreadState state = thread_state();
2141 // set_thread_state(_thread_in_vm);
2142 // {
2143 // ThreadBlockInVM tbivm(this);
2144 // java_suspend_self()
2145 // }
2146 // set_thread_state(_thread_in_vm_trans);
2147 // if (safepoint) block;
2148 // set_thread_state(state);
2149 //
2150 // but that is pretty messy. Instead we just go with the way the
2151 // code has worked before and note that this is the only path to
2152 // java_suspend_self that doesn't put the thread in _thread_blocked
2153 // mode.
2154
2155 frame_anchor()->make_walkable(this);
2156 java_suspend_self();
2157
2158 // We might be here for reasons in addition to the self-suspend request
2159 // so check for other async requests.
2160 }
2161
2162 if (check_asyncs) {
2163 check_and_handle_async_exceptions();
2164 }
2165 }
2166
2167 void JavaThread::send_thread_stop(oop java_throwable) {
2168 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2169 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2170 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2171
2172 // Do not throw asynchronous exceptions against the compiler thread
2173 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2174 if (!can_call_java()) return;
2175
2176 {
2177 // Actually throw the Throwable against the target Thread - however
2178 // only if there is no thread death exception installed already.
2179 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2180 // If the topmost frame is a runtime stub, then we are calling into
2181 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2182 // must deoptimize the caller before continuing, as the compiled exception handler table
2183 // may not be valid
2184 if (has_last_Java_frame()) {
2185 frame f = last_frame();
2186 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2187 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2188 RegisterMap reg_map(this, UseBiasedLocking);
2189 frame compiled_frame = f.sender(®_map);
2190 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2191 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2192 }
2193 }
2194 }
2195
2196 // Set async. pending exception in thread.
2197 set_pending_async_exception(java_throwable);
2198
2199 if (TraceExceptions) {
2200 ResourceMark rm;
2201 tty->print_cr("Pending Async. exception installed of type: %s", _pending_async_exception->klass()->external_name());
2202 }
2203 // for AbortVMOnException flag
2204 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2205 }
2206 }
2207
2208
2209 // Interrupt thread so it will wake up from a potential wait()
2210 Thread::interrupt(this);
2211 }
2212
2213 // External suspension mechanism.
2214 //
2215 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2216 // to any VM_locks and it is at a transition
2217 // Self-suspension will happen on the transition out of the vm.
2218 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2219 //
2220 // Guarantees on return:
2221 // + Target thread will not execute any new bytecode (that's why we need to
2222 // force a safepoint)
2223 // + Target thread will not enter any new monitors
2224 //
2225 void JavaThread::java_suspend() {
2226 { MutexLocker mu(Threads_lock);
2227 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2228 return;
2229 }
2230 }
2231
2232 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2233 if (!is_external_suspend()) {
2234 // a racing resume has cancelled us; bail out now
2235 return;
2236 }
2237
2238 // suspend is done
2239 uint32_t debug_bits = 0;
2240 // Warning: is_ext_suspend_completed() may temporarily drop the
2241 // SR_lock to allow the thread to reach a stable thread state if
2242 // it is currently in a transient thread state.
2243 if (is_ext_suspend_completed(false /* !called_by_wait */,
2244 SuspendRetryDelay, &debug_bits)) {
2245 return;
2246 }
2247 }
2248
2249 VM_ForceSafepoint vm_suspend;
2250 VMThread::execute(&vm_suspend);
2251 }
2252
2253 // Part II of external suspension.
2254 // A JavaThread self suspends when it detects a pending external suspend
2255 // request. This is usually on transitions. It is also done in places
2256 // where continuing to the next transition would surprise the caller,
2257 // e.g., monitor entry.
2258 //
2259 // Returns the number of times that the thread self-suspended.
2260 //
2261 // Note: DO NOT call java_suspend_self() when you just want to block current
2262 // thread. java_suspend_self() is the second stage of cooperative
2263 // suspension for external suspend requests and should only be used
2264 // to complete an external suspend request.
2265 //
2266 int JavaThread::java_suspend_self() {
2267 int ret = 0;
2268
2269 // we are in the process of exiting so don't suspend
2270 if (is_exiting()) {
2271 clear_external_suspend();
2272 return ret;
2273 }
2274
2275 assert(_anchor.walkable() ||
2276 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2277 "must have walkable stack");
2278
2279 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2280
2281 assert(!this->is_ext_suspended(),
2282 "a thread trying to self-suspend should not already be suspended");
2283
2284 if (this->is_suspend_equivalent()) {
2285 // If we are self-suspending as a result of the lifting of a
2286 // suspend equivalent condition, then the suspend_equivalent
2287 // flag is not cleared until we set the ext_suspended flag so
2288 // that wait_for_ext_suspend_completion() returns consistent
2289 // results.
2290 this->clear_suspend_equivalent();
2291 }
2292
2293 // A racing resume may have cancelled us before we grabbed SR_lock
2294 // above. Or another external suspend request could be waiting for us
2295 // by the time we return from SR_lock()->wait(). The thread
2296 // that requested the suspension may already be trying to walk our
2297 // stack and if we return now, we can change the stack out from under
2298 // it. This would be a "bad thing (TM)" and cause the stack walker
2299 // to crash. We stay self-suspended until there are no more pending
2300 // external suspend requests.
2301 while (is_external_suspend()) {
2302 ret++;
2303 this->set_ext_suspended();
2304
2305 // _ext_suspended flag is cleared by java_resume()
2306 while (is_ext_suspended()) {
2307 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2308 }
2309 }
2310
2311 return ret;
2312 }
2313
2314 #ifdef ASSERT
2315 // verify the JavaThread has not yet been published in the Threads::list, and
2316 // hence doesn't need protection from concurrent access at this stage
2317 void JavaThread::verify_not_published() {
2318 if (!Threads_lock->owned_by_self()) {
2319 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2320 assert(!Threads::includes(this),
2321 "java thread shouldn't have been published yet!");
2322 } else {
2323 assert(!Threads::includes(this),
2324 "java thread shouldn't have been published yet!");
2325 }
2326 }
2327 #endif
2328
2329 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2330 // progress or when _suspend_flags is non-zero.
2331 // Current thread needs to self-suspend if there is a suspend request and/or
2332 // block if a safepoint is in progress.
2333 // Async exception ISN'T checked.
2334 // Note only the ThreadInVMfromNative transition can call this function
2335 // directly and when thread state is _thread_in_native_trans
2336 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2337 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2338
2339 JavaThread *curJT = JavaThread::current();
2340 bool do_self_suspend = thread->is_external_suspend();
2341
2342 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2343
2344 // If JNIEnv proxies are allowed, don't self-suspend if the target
2345 // thread is not the current thread. In older versions of jdbx, jdbx
2346 // threads could call into the VM with another thread's JNIEnv so we
2347 // can be here operating on behalf of a suspended thread (4432884).
2348 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2349 JavaThreadState state = thread->thread_state();
2350
2351 // We mark this thread_blocked state as a suspend-equivalent so
2352 // that a caller to is_ext_suspend_completed() won't be confused.
2353 // The suspend-equivalent state is cleared by java_suspend_self().
2354 thread->set_suspend_equivalent();
2355
2356 // If the safepoint code sees the _thread_in_native_trans state, it will
2357 // wait until the thread changes to other thread state. There is no
2358 // guarantee on how soon we can obtain the SR_lock and complete the
2359 // self-suspend request. It would be a bad idea to let safepoint wait for
2360 // too long. Temporarily change the state to _thread_blocked to
2361 // let the VM thread know that this thread is ready for GC. The problem
2362 // of changing thread state is that safepoint could happen just after
2363 // java_suspend_self() returns after being resumed, and VM thread will
2364 // see the _thread_blocked state. We must check for safepoint
2365 // after restoring the state and make sure we won't leave while a safepoint
2366 // is in progress.
2367 thread->set_thread_state(_thread_blocked);
2368 thread->java_suspend_self();
2369 thread->set_thread_state(state);
2370 // Make sure new state is seen by VM thread
2371 if (os::is_MP()) {
2372 if (UseMembar) {
2373 // Force a fence between the write above and read below
2374 OrderAccess::fence();
2375 } else {
2376 // Must use this rather than serialization page in particular on Windows
2377 InterfaceSupport::serialize_memory(thread);
2378 }
2379 }
2380 }
2381
2382 if (SafepointSynchronize::do_call_back()) {
2383 // If we are safepointing, then block the caller which may not be
2384 // the same as the target thread (see above).
2385 SafepointSynchronize::block(curJT);
2386 }
2387
2388 if (thread->is_deopt_suspend()) {
2389 thread->clear_deopt_suspend();
2390 RegisterMap map(thread, false);
2391 frame f = thread->last_frame();
2392 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2393 f = f.sender(&map);
2394 }
2395 if (f.id() == thread->must_deopt_id()) {
2396 thread->clear_must_deopt_id();
2397 f.deoptimize(thread);
2398 } else {
2399 fatal("missed deoptimization!");
2400 }
2401 }
2402 }
2403
2404 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2405 // progress or when _suspend_flags is non-zero.
2406 // Current thread needs to self-suspend if there is a suspend request and/or
2407 // block if a safepoint is in progress.
2408 // Also check for pending async exception (not including unsafe access error).
2409 // Note only the native==>VM/Java barriers can call this function and when
2410 // thread state is _thread_in_native_trans.
2411 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2412 check_safepoint_and_suspend_for_native_trans(thread);
2413
2414 if (thread->has_async_exception()) {
2415 // We are in _thread_in_native_trans state, don't handle unsafe
2416 // access error since that may block.
2417 thread->check_and_handle_async_exceptions(false);
2418 }
2419 }
2420
2421 // This is a variant of the normal
2422 // check_special_condition_for_native_trans with slightly different
2423 // semantics for use by critical native wrappers. It does all the
2424 // normal checks but also performs the transition back into
2425 // thread_in_Java state. This is required so that critical natives
2426 // can potentially block and perform a GC if they are the last thread
2427 // exiting the GC_locker.
2428 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2429 check_special_condition_for_native_trans(thread);
2430
2431 // Finish the transition
2432 thread->set_thread_state(_thread_in_Java);
2433
2434 if (thread->do_critical_native_unlock()) {
2435 ThreadInVMfromJavaNoAsyncException tiv(thread);
2436 GC_locker::unlock_critical(thread);
2437 thread->clear_critical_native_unlock();
2438 }
2439 }
2440
2441 // We need to guarantee the Threads_lock here, since resumes are not
2442 // allowed during safepoint synchronization
2443 // Can only resume from an external suspension
2444 void JavaThread::java_resume() {
2445 assert_locked_or_safepoint(Threads_lock);
2446
2447 // Sanity check: thread is gone, has started exiting or the thread
2448 // was not externally suspended.
2449 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2450 return;
2451 }
2452
2453 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2454
2455 clear_external_suspend();
2456
2457 if (is_ext_suspended()) {
2458 clear_ext_suspended();
2459 SR_lock()->notify_all();
2460 }
2461 }
2462
2463 void JavaThread::create_stack_guard_pages() {
2464 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2465 address low_addr = stack_base() - stack_size();
2466 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2467
2468 int allocate = os::allocate_stack_guard_pages();
2469 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2470
2471 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2472 warning("Attempt to allocate stack guard pages failed.");
2473 return;
2474 }
2475
2476 if (os::guard_memory((char *) low_addr, len)) {
2477 _stack_guard_state = stack_guard_enabled;
2478 } else {
2479 warning("Attempt to protect stack guard pages failed.");
2480 if (os::uncommit_memory((char *) low_addr, len)) {
2481 warning("Attempt to deallocate stack guard pages failed.");
2482 }
2483 }
2484 }
2485
2486 void JavaThread::remove_stack_guard_pages() {
2487 assert(Thread::current() == this, "from different thread");
2488 if (_stack_guard_state == stack_guard_unused) return;
2489 address low_addr = stack_base() - stack_size();
2490 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2491
2492 if (os::allocate_stack_guard_pages()) {
2493 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2494 _stack_guard_state = stack_guard_unused;
2495 } else {
2496 warning("Attempt to deallocate stack guard pages failed.");
2497 }
2498 } else {
2499 if (_stack_guard_state == stack_guard_unused) return;
2500 if (os::unguard_memory((char *) low_addr, len)) {
2501 _stack_guard_state = stack_guard_unused;
2502 } else {
2503 warning("Attempt to unprotect stack guard pages failed.");
2504 }
2505 }
2506 }
2507
2508 void JavaThread::enable_stack_yellow_zone() {
2509 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2510 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2511
2512 // The base notation is from the stacks point of view, growing downward.
2513 // We need to adjust it to work correctly with guard_memory()
2514 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2515
2516 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2517 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2518
2519 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2520 _stack_guard_state = stack_guard_enabled;
2521 } else {
2522 warning("Attempt to guard stack yellow zone failed.");
2523 }
2524 enable_register_stack_guard();
2525 }
2526
2527 void JavaThread::disable_stack_yellow_zone() {
2528 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2529 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2530
2531 // Simply return if called for a thread that does not use guard pages.
2532 if (_stack_guard_state == stack_guard_unused) return;
2533
2534 // The base notation is from the stacks point of view, growing downward.
2535 // We need to adjust it to work correctly with guard_memory()
2536 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2537
2538 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2539 _stack_guard_state = stack_guard_yellow_disabled;
2540 } else {
2541 warning("Attempt to unguard stack yellow zone failed.");
2542 }
2543 disable_register_stack_guard();
2544 }
2545
2546 void JavaThread::enable_stack_red_zone() {
2547 // The base notation is from the stacks point of view, growing downward.
2548 // We need to adjust it to work correctly with guard_memory()
2549 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2550 address base = stack_red_zone_base() - stack_red_zone_size();
2551
2552 guarantee(base < stack_base(), "Error calculating stack red zone");
2553 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2554
2555 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2556 warning("Attempt to guard stack red zone failed.");
2557 }
2558 }
2559
2560 void JavaThread::disable_stack_red_zone() {
2561 // The base notation is from the stacks point of view, growing downward.
2562 // We need to adjust it to work correctly with guard_memory()
2563 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2564 address base = stack_red_zone_base() - stack_red_zone_size();
2565 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2566 warning("Attempt to unguard stack red zone failed.");
2567 }
2568 }
2569
2570 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2571 // ignore is there is no stack
2572 if (!has_last_Java_frame()) return;
2573 // traverse the stack frames. Starts from top frame.
2574 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2575 frame* fr = fst.current();
2576 f(fr, fst.register_map());
2577 }
2578 }
2579
2580
2581 #ifndef PRODUCT
2582 // Deoptimization
2583 // Function for testing deoptimization
2584 void JavaThread::deoptimize() {
2585 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2586 StackFrameStream fst(this, UseBiasedLocking);
2587 bool deopt = false; // Dump stack only if a deopt actually happens.
2588 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2589 // Iterate over all frames in the thread and deoptimize
2590 for (; !fst.is_done(); fst.next()) {
2591 if (fst.current()->can_be_deoptimized()) {
2592
2593 if (only_at) {
2594 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2595 // consists of comma or carriage return separated numbers so
2596 // search for the current bci in that string.
2597 address pc = fst.current()->pc();
2598 nmethod* nm = (nmethod*) fst.current()->cb();
2599 ScopeDesc* sd = nm->scope_desc_at(pc);
2600 char buffer[8];
2601 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2602 size_t len = strlen(buffer);
2603 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2604 while (found != NULL) {
2605 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2606 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2607 // Check that the bci found is bracketed by terminators.
2608 break;
2609 }
2610 found = strstr(found + 1, buffer);
2611 }
2612 if (!found) {
2613 continue;
2614 }
2615 }
2616
2617 if (DebugDeoptimization && !deopt) {
2618 deopt = true; // One-time only print before deopt
2619 tty->print_cr("[BEFORE Deoptimization]");
2620 trace_frames();
2621 trace_stack();
2622 }
2623 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2624 }
2625 }
2626
2627 if (DebugDeoptimization && deopt) {
2628 tty->print_cr("[AFTER Deoptimization]");
2629 trace_frames();
2630 }
2631 }
2632
2633
2634 // Make zombies
2635 void JavaThread::make_zombies() {
2636 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2637 if (fst.current()->can_be_deoptimized()) {
2638 // it is a Java nmethod
2639 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2640 nm->make_not_entrant();
2641 }
2642 }
2643 }
2644 #endif // PRODUCT
2645
2646
2647 void JavaThread::deoptimized_wrt_marked_nmethods() {
2648 if (!has_last_Java_frame()) return;
2649 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2650 StackFrameStream fst(this, UseBiasedLocking);
2651 for (; !fst.is_done(); fst.next()) {
2652 if (fst.current()->should_be_deoptimized()) {
2653 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2654 }
2655 }
2656 }
2657
2658
2659 // If the caller is a NamedThread, then remember, in the current scope,
2660 // the given JavaThread in its _processed_thread field.
2661 class RememberProcessedThread: public StackObj {
2662 NamedThread* _cur_thr;
2663 public:
2664 RememberProcessedThread(JavaThread* jthr) {
2665 Thread* thread = Thread::current();
2666 if (thread->is_Named_thread()) {
2667 _cur_thr = (NamedThread *)thread;
2668 _cur_thr->set_processed_thread(jthr);
2669 } else {
2670 _cur_thr = NULL;
2671 }
2672 }
2673
2674 ~RememberProcessedThread() {
2675 if (_cur_thr) {
2676 _cur_thr->set_processed_thread(NULL);
2677 }
2678 }
2679 };
2680
2681 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2682 // Verify that the deferred card marks have been flushed.
2683 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2684
2685 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2686 // since there may be more than one thread using each ThreadProfiler.
2687
2688 // Traverse the GCHandles
2689 Thread::oops_do(f, cld_f, cf);
2690
2691 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2692
2693 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2694 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2695
2696 if (has_last_Java_frame()) {
2697 // Record JavaThread to GC thread
2698 RememberProcessedThread rpt(this);
2699
2700 // Traverse the privileged stack
2701 if (_privileged_stack_top != NULL) {
2702 _privileged_stack_top->oops_do(f);
2703 }
2704
2705 // traverse the registered growable array
2706 if (_array_for_gc != NULL) {
2707 for (int index = 0; index < _array_for_gc->length(); index++) {
2708 f->do_oop(_array_for_gc->adr_at(index));
2709 }
2710 }
2711
2712 // Traverse the monitor chunks
2713 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2714 chunk->oops_do(f);
2715 }
2716
2717 // Traverse the execution stack
2718 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2719 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2720 }
2721 }
2722
2723 // callee_target is never live across a gc point so NULL it here should
2724 // it still contain a methdOop.
2725
2726 set_callee_target(NULL);
2727
2728 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2729 // If we have deferred set_locals there might be oops waiting to be
2730 // written
2731 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2732 if (list != NULL) {
2733 for (int i = 0; i < list->length(); i++) {
2734 list->at(i)->oops_do(f);
2735 }
2736 }
2737
2738 // Traverse instance variables at the end since the GC may be moving things
2739 // around using this function
2740 f->do_oop((oop*) &_threadObj);
2741 f->do_oop((oop*) &_vm_result);
2742 f->do_oop((oop*) &_exception_oop);
2743 f->do_oop((oop*) &_pending_async_exception);
2744
2745 if (jvmti_thread_state() != NULL) {
2746 jvmti_thread_state()->oops_do(f);
2747 }
2748 }
2749
2750 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2751 Thread::nmethods_do(cf); // (super method is a no-op)
2752
2753 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2754 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2755
2756 if (has_last_Java_frame()) {
2757 // Traverse the execution stack
2758 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2759 fst.current()->nmethods_do(cf);
2760 }
2761 }
2762 }
2763
2764 void JavaThread::metadata_do(void f(Metadata*)) {
2765 if (has_last_Java_frame()) {
2766 // Traverse the execution stack to call f() on the methods in the stack
2767 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2768 fst.current()->metadata_do(f);
2769 }
2770 } else if (is_Compiler_thread()) {
2771 // need to walk ciMetadata in current compile tasks to keep alive.
2772 CompilerThread* ct = (CompilerThread*)this;
2773 if (ct->env() != NULL) {
2774 ct->env()->metadata_do(f);
2775 }
2776 if (ct->task() != NULL) {
2777 ct->task()->metadata_do(f);
2778 }
2779 }
2780 }
2781
2782 // Printing
2783 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2784 switch (_thread_state) {
2785 case _thread_uninitialized: return "_thread_uninitialized";
2786 case _thread_new: return "_thread_new";
2787 case _thread_new_trans: return "_thread_new_trans";
2788 case _thread_in_native: return "_thread_in_native";
2789 case _thread_in_native_trans: return "_thread_in_native_trans";
2790 case _thread_in_vm: return "_thread_in_vm";
2791 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2792 case _thread_in_Java: return "_thread_in_Java";
2793 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2794 case _thread_blocked: return "_thread_blocked";
2795 case _thread_blocked_trans: return "_thread_blocked_trans";
2796 default: return "unknown thread state";
2797 }
2798 }
2799
2800 #ifndef PRODUCT
2801 void JavaThread::print_thread_state_on(outputStream *st) const {
2802 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2803 };
2804 void JavaThread::print_thread_state() const {
2805 print_thread_state_on(tty);
2806 }
2807 #endif // PRODUCT
2808
2809 // Called by Threads::print() for VM_PrintThreads operation
2810 void JavaThread::print_on(outputStream *st) const {
2811 st->print("\"%s\" ", get_thread_name());
2812 oop thread_oop = threadObj();
2813 if (thread_oop != NULL) {
2814 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2815 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2816 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2817 }
2818 Thread::print_on(st);
2819 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2820 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2821 if (thread_oop != NULL) {
2822 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2823 }
2824 #ifndef PRODUCT
2825 print_thread_state_on(st);
2826 _safepoint_state->print_on(st);
2827 #endif // PRODUCT
2828 }
2829
2830 // Called by fatal error handler. The difference between this and
2831 // JavaThread::print() is that we can't grab lock or allocate memory.
2832 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2833 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2834 oop thread_obj = threadObj();
2835 if (thread_obj != NULL) {
2836 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2837 }
2838 st->print(" [");
2839 st->print("%s", _get_thread_state_name(_thread_state));
2840 if (osthread()) {
2841 st->print(", id=%d", osthread()->thread_id());
2842 }
2843 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2844 p2i(_stack_base - _stack_size), p2i(_stack_base));
2845 st->print("]");
2846 return;
2847 }
2848
2849 // Verification
2850
2851 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2852
2853 void JavaThread::verify() {
2854 // Verify oops in the thread.
2855 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2856
2857 // Verify the stack frames.
2858 frames_do(frame_verify);
2859 }
2860
2861 // CR 6300358 (sub-CR 2137150)
2862 // Most callers of this method assume that it can't return NULL but a
2863 // thread may not have a name whilst it is in the process of attaching to
2864 // the VM - see CR 6412693, and there are places where a JavaThread can be
2865 // seen prior to having it's threadObj set (eg JNI attaching threads and
2866 // if vm exit occurs during initialization). These cases can all be accounted
2867 // for such that this method never returns NULL.
2868 const char* JavaThread::get_thread_name() const {
2869 #ifdef ASSERT
2870 // early safepoints can hit while current thread does not yet have TLS
2871 if (!SafepointSynchronize::is_at_safepoint()) {
2872 Thread *cur = Thread::current();
2873 if (!(cur->is_Java_thread() && cur == this)) {
2874 // Current JavaThreads are allowed to get their own name without
2875 // the Threads_lock.
2876 assert_locked_or_safepoint(Threads_lock);
2877 }
2878 }
2879 #endif // ASSERT
2880 return get_thread_name_string();
2881 }
2882
2883 // Returns a non-NULL representation of this thread's name, or a suitable
2884 // descriptive string if there is no set name
2885 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2886 const char* name_str;
2887 oop thread_obj = threadObj();
2888 if (thread_obj != NULL) {
2889 oop name = java_lang_Thread::name(thread_obj);
2890 if (name != NULL) {
2891 if (buf == NULL) {
2892 name_str = java_lang_String::as_utf8_string(name);
2893 } else {
2894 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2895 }
2896 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2897 name_str = "<no-name - thread is attaching>";
2898 } else {
2899 name_str = Thread::name();
2900 }
2901 } else {
2902 name_str = Thread::name();
2903 }
2904 assert(name_str != NULL, "unexpected NULL thread name");
2905 return name_str;
2906 }
2907
2908
2909 const char* JavaThread::get_threadgroup_name() const {
2910 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2911 oop thread_obj = threadObj();
2912 if (thread_obj != NULL) {
2913 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2914 if (thread_group != NULL) {
2915 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2916 // ThreadGroup.name can be null
2917 if (name != NULL) {
2918 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2919 return str;
2920 }
2921 }
2922 }
2923 return NULL;
2924 }
2925
2926 const char* JavaThread::get_parent_name() const {
2927 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2928 oop thread_obj = threadObj();
2929 if (thread_obj != NULL) {
2930 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2931 if (thread_group != NULL) {
2932 oop parent = java_lang_ThreadGroup::parent(thread_group);
2933 if (parent != NULL) {
2934 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2935 // ThreadGroup.name can be null
2936 if (name != NULL) {
2937 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2938 return str;
2939 }
2940 }
2941 }
2942 }
2943 return NULL;
2944 }
2945
2946 ThreadPriority JavaThread::java_priority() const {
2947 oop thr_oop = threadObj();
2948 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2949 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2950 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2951 return priority;
2952 }
2953
2954 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2955
2956 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2957 // Link Java Thread object <-> C++ Thread
2958
2959 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2960 // and put it into a new Handle. The Handle "thread_oop" can then
2961 // be used to pass the C++ thread object to other methods.
2962
2963 // Set the Java level thread object (jthread) field of the
2964 // new thread (a JavaThread *) to C++ thread object using the
2965 // "thread_oop" handle.
2966
2967 // Set the thread field (a JavaThread *) of the
2968 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2969
2970 Handle thread_oop(Thread::current(),
2971 JNIHandles::resolve_non_null(jni_thread));
2972 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2973 "must be initialized");
2974 set_threadObj(thread_oop());
2975 java_lang_Thread::set_thread(thread_oop(), this);
2976
2977 if (prio == NoPriority) {
2978 prio = java_lang_Thread::priority(thread_oop());
2979 assert(prio != NoPriority, "A valid priority should be present");
2980 }
2981
2982 // Push the Java priority down to the native thread; needs Threads_lock
2983 Thread::set_priority(this, prio);
2984
2985 prepare_ext();
2986
2987 // Add the new thread to the Threads list and set it in motion.
2988 // We must have threads lock in order to call Threads::add.
2989 // It is crucial that we do not block before the thread is
2990 // added to the Threads list for if a GC happens, then the java_thread oop
2991 // will not be visited by GC.
2992 Threads::add(this);
2993 }
2994
2995 oop JavaThread::current_park_blocker() {
2996 // Support for JSR-166 locks
2997 oop thread_oop = threadObj();
2998 if (thread_oop != NULL &&
2999 JDK_Version::current().supports_thread_park_blocker()) {
3000 return java_lang_Thread::park_blocker(thread_oop);
3001 }
3002 return NULL;
3003 }
3004
3005
3006 void JavaThread::print_stack_on(outputStream* st) {
3007 if (!has_last_Java_frame()) return;
3008 ResourceMark rm;
3009 HandleMark hm;
3010
3011 RegisterMap reg_map(this);
3012 vframe* start_vf = last_java_vframe(®_map);
3013 int count = 0;
3014 for (vframe* f = start_vf; f; f = f->sender()) {
3015 if (f->is_java_frame()) {
3016 javaVFrame* jvf = javaVFrame::cast(f);
3017 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3018
3019 // Print out lock information
3020 if (JavaMonitorsInStackTrace) {
3021 jvf->print_lock_info_on(st, count);
3022 }
3023 } else {
3024 // Ignore non-Java frames
3025 }
3026
3027 // Bail-out case for too deep stacks
3028 count++;
3029 if (MaxJavaStackTraceDepth == count) return;
3030 }
3031 }
3032
3033
3034 // JVMTI PopFrame support
3035 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3036 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3037 if (in_bytes(size_in_bytes) != 0) {
3038 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3039 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3040 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3041 }
3042 }
3043
3044 void* JavaThread::popframe_preserved_args() {
3045 return _popframe_preserved_args;
3046 }
3047
3048 ByteSize JavaThread::popframe_preserved_args_size() {
3049 return in_ByteSize(_popframe_preserved_args_size);
3050 }
3051
3052 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3053 int sz = in_bytes(popframe_preserved_args_size());
3054 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3055 return in_WordSize(sz / wordSize);
3056 }
3057
3058 void JavaThread::popframe_free_preserved_args() {
3059 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3060 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3061 _popframe_preserved_args = NULL;
3062 _popframe_preserved_args_size = 0;
3063 }
3064
3065 #ifndef PRODUCT
3066
3067 void JavaThread::trace_frames() {
3068 tty->print_cr("[Describe stack]");
3069 int frame_no = 1;
3070 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3071 tty->print(" %d. ", frame_no++);
3072 fst.current()->print_value_on(tty, this);
3073 tty->cr();
3074 }
3075 }
3076
3077 class PrintAndVerifyOopClosure: public OopClosure {
3078 protected:
3079 template <class T> inline void do_oop_work(T* p) {
3080 oop obj = oopDesc::load_decode_heap_oop(p);
3081 if (obj == NULL) return;
3082 tty->print(INTPTR_FORMAT ": ", p2i(p));
3083 if (obj->is_oop_or_null()) {
3084 if (obj->is_objArray()) {
3085 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3086 } else {
3087 obj->print();
3088 }
3089 } else {
3090 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3091 }
3092 tty->cr();
3093 }
3094 public:
3095 virtual void do_oop(oop* p) { do_oop_work(p); }
3096 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3097 };
3098
3099
3100 static void oops_print(frame* f, const RegisterMap *map) {
3101 PrintAndVerifyOopClosure print;
3102 f->print_value();
3103 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3104 }
3105
3106 // Print our all the locations that contain oops and whether they are
3107 // valid or not. This useful when trying to find the oldest frame
3108 // where an oop has gone bad since the frame walk is from youngest to
3109 // oldest.
3110 void JavaThread::trace_oops() {
3111 tty->print_cr("[Trace oops]");
3112 frames_do(oops_print);
3113 }
3114
3115
3116 #ifdef ASSERT
3117 // Print or validate the layout of stack frames
3118 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3119 ResourceMark rm;
3120 PRESERVE_EXCEPTION_MARK;
3121 FrameValues values;
3122 int frame_no = 0;
3123 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3124 fst.current()->describe(values, ++frame_no);
3125 if (depth == frame_no) break;
3126 }
3127 if (validate_only) {
3128 values.validate();
3129 } else {
3130 tty->print_cr("[Describe stack layout]");
3131 values.print(this);
3132 }
3133 }
3134 #endif
3135
3136 void JavaThread::trace_stack_from(vframe* start_vf) {
3137 ResourceMark rm;
3138 int vframe_no = 1;
3139 for (vframe* f = start_vf; f; f = f->sender()) {
3140 if (f->is_java_frame()) {
3141 javaVFrame::cast(f)->print_activation(vframe_no++);
3142 } else {
3143 f->print();
3144 }
3145 if (vframe_no > StackPrintLimit) {
3146 tty->print_cr("...<more frames>...");
3147 return;
3148 }
3149 }
3150 }
3151
3152
3153 void JavaThread::trace_stack() {
3154 if (!has_last_Java_frame()) return;
3155 ResourceMark rm;
3156 HandleMark hm;
3157 RegisterMap reg_map(this);
3158 trace_stack_from(last_java_vframe(®_map));
3159 }
3160
3161
3162 #endif // PRODUCT
3163
3164
3165 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3166 assert(reg_map != NULL, "a map must be given");
3167 frame f = last_frame();
3168 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3169 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3170 }
3171 return NULL;
3172 }
3173
3174
3175 Klass* JavaThread::security_get_caller_class(int depth) {
3176 vframeStream vfst(this);
3177 vfst.security_get_caller_frame(depth);
3178 if (!vfst.at_end()) {
3179 return vfst.method()->method_holder();
3180 }
3181 return NULL;
3182 }
3183
3184 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3185 assert(thread->is_Compiler_thread(), "must be compiler thread");
3186 CompileBroker::compiler_thread_loop();
3187 }
3188
3189 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3190 NMethodSweeper::sweeper_loop();
3191 }
3192
3193 // Create a CompilerThread
3194 CompilerThread::CompilerThread(CompileQueue* queue,
3195 CompilerCounters* counters)
3196 : JavaThread(&compiler_thread_entry) {
3197 _env = NULL;
3198 _log = NULL;
3199 _task = NULL;
3200 _queue = queue;
3201 _counters = counters;
3202 _buffer_blob = NULL;
3203 _compiler = NULL;
3204
3205 #ifndef PRODUCT
3206 _ideal_graph_printer = NULL;
3207 #endif
3208 }
3209
3210 bool CompilerThread::can_call_java() const {
3211 return _compiler != NULL && _compiler->is_jvmci();
3212 }
3213
3214 // Create sweeper thread
3215 CodeCacheSweeperThread::CodeCacheSweeperThread()
3216 : JavaThread(&sweeper_thread_entry) {
3217 _scanned_nmethod = NULL;
3218 }
3219 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3220 JavaThread::oops_do(f, cld_f, cf);
3221 if (_scanned_nmethod != NULL && cf != NULL) {
3222 // Safepoints can occur when the sweeper is scanning an nmethod so
3223 // process it here to make sure it isn't unloaded in the middle of
3224 // a scan.
3225 cf->do_code_blob(_scanned_nmethod);
3226 }
3227 }
3228
3229
3230 // ======= Threads ========
3231
3232 // The Threads class links together all active threads, and provides
3233 // operations over all threads. It is protected by its own Mutex
3234 // lock, which is also used in other contexts to protect thread
3235 // operations from having the thread being operated on from exiting
3236 // and going away unexpectedly (e.g., safepoint synchronization)
3237
3238 JavaThread* Threads::_thread_list = NULL;
3239 int Threads::_number_of_threads = 0;
3240 int Threads::_number_of_non_daemon_threads = 0;
3241 int Threads::_return_code = 0;
3242 int Threads::_thread_claim_parity = 0;
3243 size_t JavaThread::_stack_size_at_create = 0;
3244 #ifdef ASSERT
3245 bool Threads::_vm_complete = false;
3246 #endif
3247
3248 // All JavaThreads
3249 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3250
3251 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3252 void Threads::threads_do(ThreadClosure* tc) {
3253 assert_locked_or_safepoint(Threads_lock);
3254 // ALL_JAVA_THREADS iterates through all JavaThreads
3255 ALL_JAVA_THREADS(p) {
3256 tc->do_thread(p);
3257 }
3258 // Someday we could have a table or list of all non-JavaThreads.
3259 // For now, just manually iterate through them.
3260 tc->do_thread(VMThread::vm_thread());
3261 Universe::heap()->gc_threads_do(tc);
3262 WatcherThread *wt = WatcherThread::watcher_thread();
3263 // Strictly speaking, the following NULL check isn't sufficient to make sure
3264 // the data for WatcherThread is still valid upon being examined. However,
3265 // considering that WatchThread terminates when the VM is on the way to
3266 // exit at safepoint, the chance of the above is extremely small. The right
3267 // way to prevent termination of WatcherThread would be to acquire
3268 // Terminator_lock, but we can't do that without violating the lock rank
3269 // checking in some cases.
3270 if (wt != NULL) {
3271 tc->do_thread(wt);
3272 }
3273
3274 // If CompilerThreads ever become non-JavaThreads, add them here
3275 }
3276
3277 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3278 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3279
3280 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3281 create_vm_init_libraries();
3282 }
3283
3284 initialize_class(vmSymbols::java_lang_String(), CHECK);
3285
3286 // Initialize java_lang.System (needed before creating the thread)
3287 initialize_class(vmSymbols::java_lang_System(), CHECK);
3288 // The VM creates & returns objects of this class. Make sure it's initialized.
3289 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3290 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3291 Handle thread_group = create_initial_thread_group(CHECK);
3292 Universe::set_main_thread_group(thread_group());
3293 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3294 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3295 main_thread->set_threadObj(thread_object);
3296 // Set thread status to running since main thread has
3297 // been started and running.
3298 java_lang_Thread::set_thread_status(thread_object,
3299 java_lang_Thread::RUNNABLE);
3300
3301 // The VM preresolves methods to these classes. Make sure that they get initialized
3302 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3303 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3304 call_initializeSystemClass(CHECK);
3305
3306 // get the Java runtime name after java.lang.System is initialized
3307 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3308 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3309
3310 // an instance of OutOfMemory exception has been allocated earlier
3311 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3312 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3313 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3314 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3315 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3316 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3317 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3318 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3319 }
3320
3321 void Threads::initialize_jsr292_core_classes(TRAPS) {
3322 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3323 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3324 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3325 }
3326
3327 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3328 extern void JDK_Version_init();
3329
3330 // Preinitialize version info.
3331 VM_Version::early_initialize();
3332
3333 // Check version
3334 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3335
3336 // Initialize the output stream module
3337 ostream_init();
3338
3339 // Process java launcher properties.
3340 Arguments::process_sun_java_launcher_properties(args);
3341
3342 // Initialize the os module before using TLS
3343 os::init();
3344
3345 // Record VM creation timing statistics
3346 TraceVmCreationTime create_vm_timer;
3347 create_vm_timer.start();
3348
3349 // Initialize system properties.
3350 Arguments::init_system_properties();
3351
3352 // So that JDK version can be used as a discriminator when parsing arguments
3353 JDK_Version_init();
3354
3355 // Update/Initialize System properties after JDK version number is known
3356 Arguments::init_version_specific_system_properties();
3357
3358 // Make sure to initialize log configuration *before* parsing arguments
3359 LogConfiguration::initialize(create_vm_timer.begin_time());
3360
3361 // Parse arguments
3362 jint parse_result = Arguments::parse(args);
3363 if (parse_result != JNI_OK) return parse_result;
3364
3365 os::init_before_ergo();
3366
3367 jint ergo_result = Arguments::apply_ergo();
3368 if (ergo_result != JNI_OK) return ergo_result;
3369
3370 // Final check of all ranges after ergonomics which may change values.
3371 if (!CommandLineFlagRangeList::check_ranges()) {
3372 return JNI_EINVAL;
3373 }
3374
3375 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3376 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3377 if (!constraint_result) {
3378 return JNI_EINVAL;
3379 }
3380
3381 if (PauseAtStartup) {
3382 os::pause();
3383 }
3384
3385 HOTSPOT_VM_INIT_BEGIN();
3386
3387 // Timing (must come after argument parsing)
3388 TraceTime timer("Create VM", TraceStartupTime);
3389
3390 // Initialize the os module after parsing the args
3391 jint os_init_2_result = os::init_2();
3392 if (os_init_2_result != JNI_OK) return os_init_2_result;
3393
3394 jint adjust_after_os_result = Arguments::adjust_after_os();
3395 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3396
3397 // Initialize output stream logging
3398 ostream_init_log();
3399
3400 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3401 // Must be before create_vm_init_agents()
3402 if (Arguments::init_libraries_at_startup()) {
3403 convert_vm_init_libraries_to_agents();
3404 }
3405
3406 // Launch -agentlib/-agentpath and converted -Xrun agents
3407 if (Arguments::init_agents_at_startup()) {
3408 create_vm_init_agents();
3409 }
3410
3411 // Initialize Threads state
3412 _thread_list = NULL;
3413 _number_of_threads = 0;
3414 _number_of_non_daemon_threads = 0;
3415
3416 // Initialize global data structures and create system classes in heap
3417 vm_init_globals();
3418
3419 #if INCLUDE_JVMCI
3420 if (JVMCICounterSize > 0) {
3421 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3422 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3423 } else {
3424 JavaThread::_jvmci_old_thread_counters = NULL;
3425 }
3426 #endif // INCLUDE_JVMCI
3427
3428 // Attach the main thread to this os thread
3429 JavaThread* main_thread = new JavaThread();
3430 main_thread->set_thread_state(_thread_in_vm);
3431 main_thread->initialize_thread_current();
3432 // must do this before set_active_handles
3433 main_thread->record_stack_base_and_size();
3434 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3435
3436 if (!main_thread->set_as_starting_thread()) {
3437 vm_shutdown_during_initialization(
3438 "Failed necessary internal allocation. Out of swap space");
3439 delete main_thread;
3440 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3441 return JNI_ENOMEM;
3442 }
3443
3444 // Enable guard page *after* os::create_main_thread(), otherwise it would
3445 // crash Linux VM, see notes in os_linux.cpp.
3446 main_thread->create_stack_guard_pages();
3447
3448 // Initialize Java-Level synchronization subsystem
3449 ObjectMonitor::Initialize();
3450
3451 // Initialize global modules
3452 jint status = init_globals();
3453 if (status != JNI_OK) {
3454 delete main_thread;
3455 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3456 return status;
3457 }
3458
3459 // Should be done after the heap is fully created
3460 main_thread->cache_global_variables();
3461
3462 HandleMark hm;
3463
3464 { MutexLocker mu(Threads_lock);
3465 Threads::add(main_thread);
3466 }
3467
3468 // Any JVMTI raw monitors entered in onload will transition into
3469 // real raw monitor. VM is setup enough here for raw monitor enter.
3470 JvmtiExport::transition_pending_onload_raw_monitors();
3471
3472 // Create the VMThread
3473 { TraceTime timer("Start VMThread", TraceStartupTime);
3474 VMThread::create();
3475 Thread* vmthread = VMThread::vm_thread();
3476
3477 if (!os::create_thread(vmthread, os::vm_thread)) {
3478 vm_exit_during_initialization("Cannot create VM thread. "
3479 "Out of system resources.");
3480 }
3481
3482 // Wait for the VM thread to become ready, and VMThread::run to initialize
3483 // Monitors can have spurious returns, must always check another state flag
3484 {
3485 MutexLocker ml(Notify_lock);
3486 os::start_thread(vmthread);
3487 while (vmthread->active_handles() == NULL) {
3488 Notify_lock->wait();
3489 }
3490 }
3491 }
3492
3493 assert(Universe::is_fully_initialized(), "not initialized");
3494 if (VerifyDuringStartup) {
3495 // Make sure we're starting with a clean slate.
3496 VM_Verify verify_op;
3497 VMThread::execute(&verify_op);
3498 }
3499
3500 Thread* THREAD = Thread::current();
3501
3502 // At this point, the Universe is initialized, but we have not executed
3503 // any byte code. Now is a good time (the only time) to dump out the
3504 // internal state of the JVM for sharing.
3505 if (DumpSharedSpaces) {
3506 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3507 ShouldNotReachHere();
3508 }
3509
3510 // Always call even when there are not JVMTI environments yet, since environments
3511 // may be attached late and JVMTI must track phases of VM execution
3512 JvmtiExport::enter_start_phase();
3513
3514 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3515 JvmtiExport::post_vm_start();
3516
3517 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3518
3519 // We need this for ClassDataSharing - the initial vm.info property is set
3520 // with the default value of CDS "sharing" which may be reset through
3521 // command line options.
3522 reset_vm_info_property(CHECK_JNI_ERR);
3523
3524 quicken_jni_functions();
3525
3526 // Must be run after init_ft which initializes ft_enabled
3527 if (TRACE_INITIALIZE() != JNI_OK) {
3528 vm_exit_during_initialization("Failed to initialize tracing backend");
3529 }
3530
3531 // Set flag that basic initialization has completed. Used by exceptions and various
3532 // debug stuff, that does not work until all basic classes have been initialized.
3533 set_init_completed();
3534
3535 LogConfiguration::post_initialize();
3536 Metaspace::post_initialize();
3537
3538 HOTSPOT_VM_INIT_END();
3539
3540 // record VM initialization completion time
3541 #if INCLUDE_MANAGEMENT
3542 Management::record_vm_init_completed();
3543 #endif // INCLUDE_MANAGEMENT
3544
3545 // Compute system loader. Note that this has to occur after set_init_completed, since
3546 // valid exceptions may be thrown in the process.
3547 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3548 // set_init_completed has just been called, causing exceptions not to be shortcut
3549 // anymore. We call vm_exit_during_initialization directly instead.
3550 SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR));
3551
3552 #if INCLUDE_ALL_GCS
3553 // Support for ConcurrentMarkSweep. This should be cleaned up
3554 // and better encapsulated. The ugly nested if test would go away
3555 // once things are properly refactored. XXX YSR
3556 if (UseConcMarkSweepGC || UseG1GC) {
3557 if (UseConcMarkSweepGC) {
3558 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3559 } else {
3560 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3561 }
3562 }
3563 #endif // INCLUDE_ALL_GCS
3564
3565 // Always call even when there are not JVMTI environments yet, since environments
3566 // may be attached late and JVMTI must track phases of VM execution
3567 JvmtiExport::enter_live_phase();
3568
3569 // Signal Dispatcher needs to be started before VMInit event is posted
3570 os::signal_init();
3571
3572 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3573 if (!DisableAttachMechanism) {
3574 AttachListener::vm_start();
3575 if (StartAttachListener || AttachListener::init_at_startup()) {
3576 AttachListener::init();
3577 }
3578 }
3579
3580 // Launch -Xrun agents
3581 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3582 // back-end can launch with -Xdebug -Xrunjdwp.
3583 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3584 create_vm_init_libraries();
3585 }
3586
3587 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3588 JvmtiExport::post_vm_initialized();
3589
3590 if (TRACE_START() != JNI_OK) {
3591 vm_exit_during_initialization("Failed to start tracing backend.");
3592 }
3593
3594 if (CleanChunkPoolAsync) {
3595 Chunk::start_chunk_pool_cleaner_task();
3596 }
3597
3598 #if INCLUDE_JVMCI
3599 if (EnableJVMCI) {
3600 const char* jvmciCompiler = Arguments::PropertyList_get_value(Arguments::system_properties(), "jvmci.compiler");
3601 if (jvmciCompiler != NULL) {
3602 JVMCIRuntime::save_compiler(jvmciCompiler);
3603 }
3604 }
3605 #endif // INCLUDE_JVMCI
3606
3607 // initialize compiler(s)
3608 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI
3609 CompileBroker::compilation_init();
3610 #endif
3611
3612 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3613 // It is done after compilers are initialized, because otherwise compilations of
3614 // signature polymorphic MH intrinsics can be missed
3615 // (see SystemDictionary::find_method_handle_intrinsic).
3616 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3617
3618 #if INCLUDE_MANAGEMENT
3619 Management::initialize(THREAD);
3620
3621 if (HAS_PENDING_EXCEPTION) {
3622 // management agent fails to start possibly due to
3623 // configuration problem and is responsible for printing
3624 // stack trace if appropriate. Simply exit VM.
3625 vm_exit(1);
3626 }
3627 #endif // INCLUDE_MANAGEMENT
3628
3629 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3630 if (MemProfiling) MemProfiler::engage();
3631 StatSampler::engage();
3632 if (CheckJNICalls) JniPeriodicChecker::engage();
3633
3634 BiasedLocking::init();
3635
3636 #if INCLUDE_RTM_OPT
3637 RTMLockingCounters::init();
3638 #endif
3639
3640 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3641 call_postVMInitHook(THREAD);
3642 // The Java side of PostVMInitHook.run must deal with all
3643 // exceptions and provide means of diagnosis.
3644 if (HAS_PENDING_EXCEPTION) {
3645 CLEAR_PENDING_EXCEPTION;
3646 }
3647 }
3648
3649 {
3650 MutexLocker ml(PeriodicTask_lock);
3651 // Make sure the WatcherThread can be started by WatcherThread::start()
3652 // or by dynamic enrollment.
3653 WatcherThread::make_startable();
3654 // Start up the WatcherThread if there are any periodic tasks
3655 // NOTE: All PeriodicTasks should be registered by now. If they
3656 // aren't, late joiners might appear to start slowly (we might
3657 // take a while to process their first tick).
3658 if (PeriodicTask::num_tasks() > 0) {
3659 WatcherThread::start();
3660 }
3661 }
3662
3663 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3664
3665 create_vm_timer.end();
3666 #ifdef ASSERT
3667 _vm_complete = true;
3668 #endif
3669 return JNI_OK;
3670 }
3671
3672 // type for the Agent_OnLoad and JVM_OnLoad entry points
3673 extern "C" {
3674 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3675 }
3676 // Find a command line agent library and return its entry point for
3677 // -agentlib: -agentpath: -Xrun
3678 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3679 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3680 const char *on_load_symbols[],
3681 size_t num_symbol_entries) {
3682 OnLoadEntry_t on_load_entry = NULL;
3683 void *library = NULL;
3684
3685 if (!agent->valid()) {
3686 char buffer[JVM_MAXPATHLEN];
3687 char ebuf[1024] = "";
3688 const char *name = agent->name();
3689 const char *msg = "Could not find agent library ";
3690
3691 // First check to see if agent is statically linked into executable
3692 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3693 library = agent->os_lib();
3694 } else if (agent->is_absolute_path()) {
3695 library = os::dll_load(name, ebuf, sizeof ebuf);
3696 if (library == NULL) {
3697 const char *sub_msg = " in absolute path, with error: ";
3698 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3699 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3700 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3701 // If we can't find the agent, exit.
3702 vm_exit_during_initialization(buf, NULL);
3703 FREE_C_HEAP_ARRAY(char, buf);
3704 }
3705 } else {
3706 // Try to load the agent from the standard dll directory
3707 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3708 name)) {
3709 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3710 }
3711 if (library == NULL) { // Try the local directory
3712 char ns[1] = {0};
3713 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3714 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3715 }
3716 if (library == NULL) {
3717 const char *sub_msg = " on the library path, with error: ";
3718 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3719 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3720 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3721 // If we can't find the agent, exit.
3722 vm_exit_during_initialization(buf, NULL);
3723 FREE_C_HEAP_ARRAY(char, buf);
3724 }
3725 }
3726 }
3727 agent->set_os_lib(library);
3728 agent->set_valid();
3729 }
3730
3731 // Find the OnLoad function.
3732 on_load_entry =
3733 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3734 false,
3735 on_load_symbols,
3736 num_symbol_entries));
3737 return on_load_entry;
3738 }
3739
3740 // Find the JVM_OnLoad entry point
3741 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3742 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3743 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3744 }
3745
3746 // Find the Agent_OnLoad entry point
3747 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3748 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3749 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3750 }
3751
3752 // For backwards compatibility with -Xrun
3753 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3754 // treated like -agentpath:
3755 // Must be called before agent libraries are created
3756 void Threads::convert_vm_init_libraries_to_agents() {
3757 AgentLibrary* agent;
3758 AgentLibrary* next;
3759
3760 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3761 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3762 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3763
3764 // If there is an JVM_OnLoad function it will get called later,
3765 // otherwise see if there is an Agent_OnLoad
3766 if (on_load_entry == NULL) {
3767 on_load_entry = lookup_agent_on_load(agent);
3768 if (on_load_entry != NULL) {
3769 // switch it to the agent list -- so that Agent_OnLoad will be called,
3770 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3771 Arguments::convert_library_to_agent(agent);
3772 } else {
3773 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3774 }
3775 }
3776 }
3777 }
3778
3779 // Create agents for -agentlib: -agentpath: and converted -Xrun
3780 // Invokes Agent_OnLoad
3781 // Called very early -- before JavaThreads exist
3782 void Threads::create_vm_init_agents() {
3783 extern struct JavaVM_ main_vm;
3784 AgentLibrary* agent;
3785
3786 JvmtiExport::enter_onload_phase();
3787
3788 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3789 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3790
3791 if (on_load_entry != NULL) {
3792 // Invoke the Agent_OnLoad function
3793 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3794 if (err != JNI_OK) {
3795 vm_exit_during_initialization("agent library failed to init", agent->name());
3796 }
3797 } else {
3798 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3799 }
3800 }
3801 JvmtiExport::enter_primordial_phase();
3802 }
3803
3804 extern "C" {
3805 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3806 }
3807
3808 void Threads::shutdown_vm_agents() {
3809 // Send any Agent_OnUnload notifications
3810 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3811 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3812 extern struct JavaVM_ main_vm;
3813 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3814
3815 // Find the Agent_OnUnload function.
3816 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3817 os::find_agent_function(agent,
3818 false,
3819 on_unload_symbols,
3820 num_symbol_entries));
3821
3822 // Invoke the Agent_OnUnload function
3823 if (unload_entry != NULL) {
3824 JavaThread* thread = JavaThread::current();
3825 ThreadToNativeFromVM ttn(thread);
3826 HandleMark hm(thread);
3827 (*unload_entry)(&main_vm);
3828 }
3829 }
3830 }
3831
3832 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3833 // Invokes JVM_OnLoad
3834 void Threads::create_vm_init_libraries() {
3835 extern struct JavaVM_ main_vm;
3836 AgentLibrary* agent;
3837
3838 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3839 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3840
3841 if (on_load_entry != NULL) {
3842 // Invoke the JVM_OnLoad function
3843 JavaThread* thread = JavaThread::current();
3844 ThreadToNativeFromVM ttn(thread);
3845 HandleMark hm(thread);
3846 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3847 if (err != JNI_OK) {
3848 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3849 }
3850 } else {
3851 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3852 }
3853 }
3854 }
3855
3856 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3857 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3858
3859 JavaThread* java_thread = NULL;
3860 // Sequential search for now. Need to do better optimization later.
3861 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3862 oop tobj = thread->threadObj();
3863 if (!thread->is_exiting() &&
3864 tobj != NULL &&
3865 java_tid == java_lang_Thread::thread_id(tobj)) {
3866 java_thread = thread;
3867 break;
3868 }
3869 }
3870 return java_thread;
3871 }
3872
3873
3874 // Last thread running calls java.lang.Shutdown.shutdown()
3875 void JavaThread::invoke_shutdown_hooks() {
3876 HandleMark hm(this);
3877
3878 // We could get here with a pending exception, if so clear it now.
3879 if (this->has_pending_exception()) {
3880 this->clear_pending_exception();
3881 }
3882
3883 EXCEPTION_MARK;
3884 Klass* k =
3885 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3886 THREAD);
3887 if (k != NULL) {
3888 // SystemDictionary::resolve_or_null will return null if there was
3889 // an exception. If we cannot load the Shutdown class, just don't
3890 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3891 // and finalizers (if runFinalizersOnExit is set) won't be run.
3892 // Note that if a shutdown hook was registered or runFinalizersOnExit
3893 // was called, the Shutdown class would have already been loaded
3894 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3895 instanceKlassHandle shutdown_klass (THREAD, k);
3896 JavaValue result(T_VOID);
3897 JavaCalls::call_static(&result,
3898 shutdown_klass,
3899 vmSymbols::shutdown_method_name(),
3900 vmSymbols::void_method_signature(),
3901 THREAD);
3902 }
3903 CLEAR_PENDING_EXCEPTION;
3904 }
3905
3906 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3907 // the program falls off the end of main(). Another VM exit path is through
3908 // vm_exit() when the program calls System.exit() to return a value or when
3909 // there is a serious error in VM. The two shutdown paths are not exactly
3910 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3911 // and VM_Exit op at VM level.
3912 //
3913 // Shutdown sequence:
3914 // + Shutdown native memory tracking if it is on
3915 // + Wait until we are the last non-daemon thread to execute
3916 // <-- every thing is still working at this moment -->
3917 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3918 // shutdown hooks, run finalizers if finalization-on-exit
3919 // + Call before_exit(), prepare for VM exit
3920 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3921 // currently the only user of this mechanism is File.deleteOnExit())
3922 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3923 // post thread end and vm death events to JVMTI,
3924 // stop signal thread
3925 // + Call JavaThread::exit(), it will:
3926 // > release JNI handle blocks, remove stack guard pages
3927 // > remove this thread from Threads list
3928 // <-- no more Java code from this thread after this point -->
3929 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3930 // the compiler threads at safepoint
3931 // <-- do not use anything that could get blocked by Safepoint -->
3932 // + Disable tracing at JNI/JVM barriers
3933 // + Set _vm_exited flag for threads that are still running native code
3934 // + Delete this thread
3935 // + Call exit_globals()
3936 // > deletes tty
3937 // > deletes PerfMemory resources
3938 // + Return to caller
3939
3940 bool Threads::destroy_vm() {
3941 JavaThread* thread = JavaThread::current();
3942
3943 #ifdef ASSERT
3944 _vm_complete = false;
3945 #endif
3946 // Wait until we are the last non-daemon thread to execute
3947 { MutexLocker nu(Threads_lock);
3948 while (Threads::number_of_non_daemon_threads() > 1)
3949 // This wait should make safepoint checks, wait without a timeout,
3950 // and wait as a suspend-equivalent condition.
3951 //
3952 // Note: If the FlatProfiler is running and this thread is waiting
3953 // for another non-daemon thread to finish, then the FlatProfiler
3954 // is waiting for the external suspend request on this thread to
3955 // complete. wait_for_ext_suspend_completion() will eventually
3956 // timeout, but that takes time. Making this wait a suspend-
3957 // equivalent condition solves that timeout problem.
3958 //
3959 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3960 Mutex::_as_suspend_equivalent_flag);
3961 }
3962
3963 // Hang forever on exit if we are reporting an error.
3964 if (ShowMessageBoxOnError && is_error_reported()) {
3965 os::infinite_sleep();
3966 }
3967 os::wait_for_keypress_at_exit();
3968
3969 // run Java level shutdown hooks
3970 thread->invoke_shutdown_hooks();
3971
3972 before_exit(thread);
3973
3974 thread->exit(true);
3975
3976 // Stop VM thread.
3977 {
3978 // 4945125 The vm thread comes to a safepoint during exit.
3979 // GC vm_operations can get caught at the safepoint, and the
3980 // heap is unparseable if they are caught. Grab the Heap_lock
3981 // to prevent this. The GC vm_operations will not be able to
3982 // queue until after the vm thread is dead. After this point,
3983 // we'll never emerge out of the safepoint before the VM exits.
3984
3985 MutexLocker ml(Heap_lock);
3986
3987 VMThread::wait_for_vm_thread_exit();
3988 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3989 VMThread::destroy();
3990 }
3991
3992 // clean up ideal graph printers
3993 #if defined(COMPILER2) && !defined(PRODUCT)
3994 IdealGraphPrinter::clean_up();
3995 #endif
3996
3997 // Now, all Java threads are gone except daemon threads. Daemon threads
3998 // running Java code or in VM are stopped by the Safepoint. However,
3999 // daemon threads executing native code are still running. But they
4000 // will be stopped at native=>Java/VM barriers. Note that we can't
4001 // simply kill or suspend them, as it is inherently deadlock-prone.
4002
4003 #ifndef PRODUCT
4004 // disable function tracing at JNI/JVM barriers
4005 TraceJNICalls = false;
4006 TraceJVMCalls = false;
4007 TraceRuntimeCalls = false;
4008 #endif
4009
4010 VM_Exit::set_vm_exited();
4011
4012 notify_vm_shutdown();
4013
4014 delete thread;
4015
4016 #if INCLUDE_JVMCI
4017 if (JVMCICounterSize > 0) {
4018 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4019 }
4020 #endif
4021
4022 // exit_globals() will delete tty
4023 exit_globals();
4024
4025 LogConfiguration::finalize();
4026
4027 return true;
4028 }
4029
4030
4031 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4032 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4033 return is_supported_jni_version(version);
4034 }
4035
4036
4037 jboolean Threads::is_supported_jni_version(jint version) {
4038 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4039 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4040 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4041 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4042 return JNI_FALSE;
4043 }
4044
4045
4046 void Threads::add(JavaThread* p, bool force_daemon) {
4047 // The threads lock must be owned at this point
4048 assert_locked_or_safepoint(Threads_lock);
4049
4050 // See the comment for this method in thread.hpp for its purpose and
4051 // why it is called here.
4052 p->initialize_queues();
4053 p->set_next(_thread_list);
4054 _thread_list = p;
4055 _number_of_threads++;
4056 oop threadObj = p->threadObj();
4057 bool daemon = true;
4058 // Bootstrapping problem: threadObj can be null for initial
4059 // JavaThread (or for threads attached via JNI)
4060 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4061 _number_of_non_daemon_threads++;
4062 daemon = false;
4063 }
4064
4065 ThreadService::add_thread(p, daemon);
4066
4067 // Possible GC point.
4068 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4069 }
4070
4071 void Threads::remove(JavaThread* p) {
4072 // Extra scope needed for Thread_lock, so we can check
4073 // that we do not remove thread without safepoint code notice
4074 { MutexLocker ml(Threads_lock);
4075
4076 assert(includes(p), "p must be present");
4077
4078 JavaThread* current = _thread_list;
4079 JavaThread* prev = NULL;
4080
4081 while (current != p) {
4082 prev = current;
4083 current = current->next();
4084 }
4085
4086 if (prev) {
4087 prev->set_next(current->next());
4088 } else {
4089 _thread_list = p->next();
4090 }
4091 _number_of_threads--;
4092 oop threadObj = p->threadObj();
4093 bool daemon = true;
4094 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4095 _number_of_non_daemon_threads--;
4096 daemon = false;
4097
4098 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4099 // on destroy_vm will wake up.
4100 if (number_of_non_daemon_threads() == 1) {
4101 Threads_lock->notify_all();
4102 }
4103 }
4104 ThreadService::remove_thread(p, daemon);
4105
4106 // Make sure that safepoint code disregard this thread. This is needed since
4107 // the thread might mess around with locks after this point. This can cause it
4108 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4109 // of this thread since it is removed from the queue.
4110 p->set_terminated_value();
4111 } // unlock Threads_lock
4112
4113 // Since Events::log uses a lock, we grab it outside the Threads_lock
4114 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4115 }
4116
4117 // Threads_lock must be held when this is called (or must be called during a safepoint)
4118 bool Threads::includes(JavaThread* p) {
4119 assert(Threads_lock->is_locked(), "sanity check");
4120 ALL_JAVA_THREADS(q) {
4121 if (q == p) {
4122 return true;
4123 }
4124 }
4125 return false;
4126 }
4127
4128 // Operations on the Threads list for GC. These are not explicitly locked,
4129 // but the garbage collector must provide a safe context for them to run.
4130 // In particular, these things should never be called when the Threads_lock
4131 // is held by some other thread. (Note: the Safepoint abstraction also
4132 // uses the Threads_lock to guarantee this property. It also makes sure that
4133 // all threads gets blocked when exiting or starting).
4134
4135 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4136 ALL_JAVA_THREADS(p) {
4137 p->oops_do(f, cld_f, cf);
4138 }
4139 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4140 }
4141
4142 void Threads::change_thread_claim_parity() {
4143 // Set the new claim parity.
4144 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4145 "Not in range.");
4146 _thread_claim_parity++;
4147 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4148 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4149 "Not in range.");
4150 }
4151
4152 #ifdef ASSERT
4153 void Threads::assert_all_threads_claimed() {
4154 ALL_JAVA_THREADS(p) {
4155 const int thread_parity = p->oops_do_parity();
4156 assert((thread_parity == _thread_claim_parity),
4157 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4158 }
4159 }
4160 #endif // ASSERT
4161
4162 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4163 int cp = Threads::thread_claim_parity();
4164 ALL_JAVA_THREADS(p) {
4165 if (p->claim_oops_do(is_par, cp)) {
4166 p->oops_do(f, cld_f, cf);
4167 }
4168 }
4169 VMThread* vmt = VMThread::vm_thread();
4170 if (vmt->claim_oops_do(is_par, cp)) {
4171 vmt->oops_do(f, cld_f, cf);
4172 }
4173 }
4174
4175 #if INCLUDE_ALL_GCS
4176 // Used by ParallelScavenge
4177 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4178 ALL_JAVA_THREADS(p) {
4179 q->enqueue(new ThreadRootsTask(p));
4180 }
4181 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4182 }
4183
4184 // Used by Parallel Old
4185 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4186 ALL_JAVA_THREADS(p) {
4187 q->enqueue(new ThreadRootsMarkingTask(p));
4188 }
4189 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4190 }
4191 #endif // INCLUDE_ALL_GCS
4192
4193 void Threads::nmethods_do(CodeBlobClosure* cf) {
4194 ALL_JAVA_THREADS(p) {
4195 p->nmethods_do(cf);
4196 }
4197 VMThread::vm_thread()->nmethods_do(cf);
4198 }
4199
4200 void Threads::metadata_do(void f(Metadata*)) {
4201 ALL_JAVA_THREADS(p) {
4202 p->metadata_do(f);
4203 }
4204 }
4205
4206 class ThreadHandlesClosure : public ThreadClosure {
4207 void (*_f)(Metadata*);
4208 public:
4209 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4210 virtual void do_thread(Thread* thread) {
4211 thread->metadata_handles_do(_f);
4212 }
4213 };
4214
4215 void Threads::metadata_handles_do(void f(Metadata*)) {
4216 // Only walk the Handles in Thread.
4217 ThreadHandlesClosure handles_closure(f);
4218 threads_do(&handles_closure);
4219 }
4220
4221 void Threads::deoptimized_wrt_marked_nmethods() {
4222 ALL_JAVA_THREADS(p) {
4223 p->deoptimized_wrt_marked_nmethods();
4224 }
4225 }
4226
4227
4228 // Get count Java threads that are waiting to enter the specified monitor.
4229 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4230 address monitor,
4231 bool doLock) {
4232 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4233 "must grab Threads_lock or be at safepoint");
4234 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4235
4236 int i = 0;
4237 {
4238 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4239 ALL_JAVA_THREADS(p) {
4240 if (!p->can_call_java()) continue;
4241
4242 address pending = (address)p->current_pending_monitor();
4243 if (pending == monitor) { // found a match
4244 if (i < count) result->append(p); // save the first count matches
4245 i++;
4246 }
4247 }
4248 }
4249 return result;
4250 }
4251
4252
4253 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4254 bool doLock) {
4255 assert(doLock ||
4256 Threads_lock->owned_by_self() ||
4257 SafepointSynchronize::is_at_safepoint(),
4258 "must grab Threads_lock or be at safepoint");
4259
4260 // NULL owner means not locked so we can skip the search
4261 if (owner == NULL) return NULL;
4262
4263 {
4264 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4265 ALL_JAVA_THREADS(p) {
4266 // first, see if owner is the address of a Java thread
4267 if (owner == (address)p) return p;
4268 }
4269 }
4270 // Cannot assert on lack of success here since this function may be
4271 // used by code that is trying to report useful problem information
4272 // like deadlock detection.
4273 if (UseHeavyMonitors) return NULL;
4274
4275 // If we didn't find a matching Java thread and we didn't force use of
4276 // heavyweight monitors, then the owner is the stack address of the
4277 // Lock Word in the owning Java thread's stack.
4278 //
4279 JavaThread* the_owner = NULL;
4280 {
4281 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4282 ALL_JAVA_THREADS(q) {
4283 if (q->is_lock_owned(owner)) {
4284 the_owner = q;
4285 break;
4286 }
4287 }
4288 }
4289 // cannot assert on lack of success here; see above comment
4290 return the_owner;
4291 }
4292
4293 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4294 void Threads::print_on(outputStream* st, bool print_stacks,
4295 bool internal_format, bool print_concurrent_locks) {
4296 char buf[32];
4297 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4298
4299 st->print_cr("Full thread dump %s (%s %s):",
4300 Abstract_VM_Version::vm_name(),
4301 Abstract_VM_Version::vm_release(),
4302 Abstract_VM_Version::vm_info_string());
4303 st->cr();
4304
4305 #if INCLUDE_SERVICES
4306 // Dump concurrent locks
4307 ConcurrentLocksDump concurrent_locks;
4308 if (print_concurrent_locks) {
4309 concurrent_locks.dump_at_safepoint();
4310 }
4311 #endif // INCLUDE_SERVICES
4312
4313 ALL_JAVA_THREADS(p) {
4314 ResourceMark rm;
4315 p->print_on(st);
4316 if (print_stacks) {
4317 if (internal_format) {
4318 p->trace_stack();
4319 } else {
4320 p->print_stack_on(st);
4321 }
4322 }
4323 st->cr();
4324 #if INCLUDE_SERVICES
4325 if (print_concurrent_locks) {
4326 concurrent_locks.print_locks_on(p, st);
4327 }
4328 #endif // INCLUDE_SERVICES
4329 }
4330
4331 VMThread::vm_thread()->print_on(st);
4332 st->cr();
4333 Universe::heap()->print_gc_threads_on(st);
4334 WatcherThread* wt = WatcherThread::watcher_thread();
4335 if (wt != NULL) {
4336 wt->print_on(st);
4337 st->cr();
4338 }
4339 CompileBroker::print_compiler_threads_on(st);
4340 st->flush();
4341 }
4342
4343 // Threads::print_on_error() is called by fatal error handler. It's possible
4344 // that VM is not at safepoint and/or current thread is inside signal handler.
4345 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4346 // memory (even in resource area), it might deadlock the error handler.
4347 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4348 int buflen) {
4349 bool found_current = false;
4350 st->print_cr("Java Threads: ( => current thread )");
4351 ALL_JAVA_THREADS(thread) {
4352 bool is_current = (current == thread);
4353 found_current = found_current || is_current;
4354
4355 st->print("%s", is_current ? "=>" : " ");
4356
4357 st->print(PTR_FORMAT, p2i(thread));
4358 st->print(" ");
4359 thread->print_on_error(st, buf, buflen);
4360 st->cr();
4361 }
4362 st->cr();
4363
4364 st->print_cr("Other Threads:");
4365 if (VMThread::vm_thread()) {
4366 bool is_current = (current == VMThread::vm_thread());
4367 found_current = found_current || is_current;
4368 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4369
4370 st->print(PTR_FORMAT, p2i(VMThread::vm_thread()));
4371 st->print(" ");
4372 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4373 st->cr();
4374 }
4375 WatcherThread* wt = WatcherThread::watcher_thread();
4376 if (wt != NULL) {
4377 bool is_current = (current == wt);
4378 found_current = found_current || is_current;
4379 st->print("%s", is_current ? "=>" : " ");
4380
4381 st->print(PTR_FORMAT, p2i(wt));
4382 st->print(" ");
4383 wt->print_on_error(st, buf, buflen);
4384 st->cr();
4385 }
4386 if (!found_current) {
4387 st->cr();
4388 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4389 current->print_on_error(st, buf, buflen);
4390 st->cr();
4391 }
4392 }
4393
4394 // Internal SpinLock and Mutex
4395 // Based on ParkEvent
4396
4397 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4398 //
4399 // We employ SpinLocks _only for low-contention, fixed-length
4400 // short-duration critical sections where we're concerned
4401 // about native mutex_t or HotSpot Mutex:: latency.
4402 // The mux construct provides a spin-then-block mutual exclusion
4403 // mechanism.
4404 //
4405 // Testing has shown that contention on the ListLock guarding gFreeList
4406 // is common. If we implement ListLock as a simple SpinLock it's common
4407 // for the JVM to devolve to yielding with little progress. This is true
4408 // despite the fact that the critical sections protected by ListLock are
4409 // extremely short.
4410 //
4411 // TODO-FIXME: ListLock should be of type SpinLock.
4412 // We should make this a 1st-class type, integrated into the lock
4413 // hierarchy as leaf-locks. Critically, the SpinLock structure
4414 // should have sufficient padding to avoid false-sharing and excessive
4415 // cache-coherency traffic.
4416
4417
4418 typedef volatile int SpinLockT;
4419
4420 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4421 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4422 return; // normal fast-path return
4423 }
4424
4425 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4426 TEVENT(SpinAcquire - ctx);
4427 int ctr = 0;
4428 int Yields = 0;
4429 for (;;) {
4430 while (*adr != 0) {
4431 ++ctr;
4432 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4433 if (Yields > 5) {
4434 os::naked_short_sleep(1);
4435 } else {
4436 os::naked_yield();
4437 ++Yields;
4438 }
4439 } else {
4440 SpinPause();
4441 }
4442 }
4443 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4444 }
4445 }
4446
4447 void Thread::SpinRelease(volatile int * adr) {
4448 assert(*adr != 0, "invariant");
4449 OrderAccess::fence(); // guarantee at least release consistency.
4450 // Roach-motel semantics.
4451 // It's safe if subsequent LDs and STs float "up" into the critical section,
4452 // but prior LDs and STs within the critical section can't be allowed
4453 // to reorder or float past the ST that releases the lock.
4454 // Loads and stores in the critical section - which appear in program
4455 // order before the store that releases the lock - must also appear
4456 // before the store that releases the lock in memory visibility order.
4457 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4458 // the ST of 0 into the lock-word which releases the lock, so fence
4459 // more than covers this on all platforms.
4460 *adr = 0;
4461 }
4462
4463 // muxAcquire and muxRelease:
4464 //
4465 // * muxAcquire and muxRelease support a single-word lock-word construct.
4466 // The LSB of the word is set IFF the lock is held.
4467 // The remainder of the word points to the head of a singly-linked list
4468 // of threads blocked on the lock.
4469 //
4470 // * The current implementation of muxAcquire-muxRelease uses its own
4471 // dedicated Thread._MuxEvent instance. If we're interested in
4472 // minimizing the peak number of extant ParkEvent instances then
4473 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4474 // as certain invariants were satisfied. Specifically, care would need
4475 // to be taken with regards to consuming unpark() "permits".
4476 // A safe rule of thumb is that a thread would never call muxAcquire()
4477 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4478 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4479 // consume an unpark() permit intended for monitorenter, for instance.
4480 // One way around this would be to widen the restricted-range semaphore
4481 // implemented in park(). Another alternative would be to provide
4482 // multiple instances of the PlatformEvent() for each thread. One
4483 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4484 //
4485 // * Usage:
4486 // -- Only as leaf locks
4487 // -- for short-term locking only as muxAcquire does not perform
4488 // thread state transitions.
4489 //
4490 // Alternatives:
4491 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4492 // but with parking or spin-then-park instead of pure spinning.
4493 // * Use Taura-Oyama-Yonenzawa locks.
4494 // * It's possible to construct a 1-0 lock if we encode the lockword as
4495 // (List,LockByte). Acquire will CAS the full lockword while Release
4496 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4497 // acquiring threads use timers (ParkTimed) to detect and recover from
4498 // the stranding window. Thread/Node structures must be aligned on 256-byte
4499 // boundaries by using placement-new.
4500 // * Augment MCS with advisory back-link fields maintained with CAS().
4501 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4502 // The validity of the backlinks must be ratified before we trust the value.
4503 // If the backlinks are invalid the exiting thread must back-track through the
4504 // the forward links, which are always trustworthy.
4505 // * Add a successor indication. The LockWord is currently encoded as
4506 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4507 // to provide the usual futile-wakeup optimization.
4508 // See RTStt for details.
4509 // * Consider schedctl.sc_nopreempt to cover the critical section.
4510 //
4511
4512
4513 typedef volatile intptr_t MutexT; // Mux Lock-word
4514 enum MuxBits { LOCKBIT = 1 };
4515
4516 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4517 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4518 if (w == 0) return;
4519 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4520 return;
4521 }
4522
4523 TEVENT(muxAcquire - Contention);
4524 ParkEvent * const Self = Thread::current()->_MuxEvent;
4525 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4526 for (;;) {
4527 int its = (os::is_MP() ? 100 : 0) + 1;
4528
4529 // Optional spin phase: spin-then-park strategy
4530 while (--its >= 0) {
4531 w = *Lock;
4532 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4533 return;
4534 }
4535 }
4536
4537 Self->reset();
4538 Self->OnList = intptr_t(Lock);
4539 // The following fence() isn't _strictly necessary as the subsequent
4540 // CAS() both serializes execution and ratifies the fetched *Lock value.
4541 OrderAccess::fence();
4542 for (;;) {
4543 w = *Lock;
4544 if ((w & LOCKBIT) == 0) {
4545 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4546 Self->OnList = 0; // hygiene - allows stronger asserts
4547 return;
4548 }
4549 continue; // Interference -- *Lock changed -- Just retry
4550 }
4551 assert(w & LOCKBIT, "invariant");
4552 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4553 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4554 }
4555
4556 while (Self->OnList != 0) {
4557 Self->park();
4558 }
4559 }
4560 }
4561
4562 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4563 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4564 if (w == 0) return;
4565 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4566 return;
4567 }
4568
4569 TEVENT(muxAcquire - Contention);
4570 ParkEvent * ReleaseAfter = NULL;
4571 if (ev == NULL) {
4572 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4573 }
4574 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4575 for (;;) {
4576 guarantee(ev->OnList == 0, "invariant");
4577 int its = (os::is_MP() ? 100 : 0) + 1;
4578
4579 // Optional spin phase: spin-then-park strategy
4580 while (--its >= 0) {
4581 w = *Lock;
4582 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4583 if (ReleaseAfter != NULL) {
4584 ParkEvent::Release(ReleaseAfter);
4585 }
4586 return;
4587 }
4588 }
4589
4590 ev->reset();
4591 ev->OnList = intptr_t(Lock);
4592 // The following fence() isn't _strictly necessary as the subsequent
4593 // CAS() both serializes execution and ratifies the fetched *Lock value.
4594 OrderAccess::fence();
4595 for (;;) {
4596 w = *Lock;
4597 if ((w & LOCKBIT) == 0) {
4598 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4599 ev->OnList = 0;
4600 // We call ::Release while holding the outer lock, thus
4601 // artificially lengthening the critical section.
4602 // Consider deferring the ::Release() until the subsequent unlock(),
4603 // after we've dropped the outer lock.
4604 if (ReleaseAfter != NULL) {
4605 ParkEvent::Release(ReleaseAfter);
4606 }
4607 return;
4608 }
4609 continue; // Interference -- *Lock changed -- Just retry
4610 }
4611 assert(w & LOCKBIT, "invariant");
4612 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4613 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4614 }
4615
4616 while (ev->OnList != 0) {
4617 ev->park();
4618 }
4619 }
4620 }
4621
4622 // Release() must extract a successor from the list and then wake that thread.
4623 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4624 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4625 // Release() would :
4626 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4627 // (B) Extract a successor from the private list "in-hand"
4628 // (C) attempt to CAS() the residual back into *Lock over null.
4629 // If there were any newly arrived threads and the CAS() would fail.
4630 // In that case Release() would detach the RATs, re-merge the list in-hand
4631 // with the RATs and repeat as needed. Alternately, Release() might
4632 // detach and extract a successor, but then pass the residual list to the wakee.
4633 // The wakee would be responsible for reattaching and remerging before it
4634 // competed for the lock.
4635 //
4636 // Both "pop" and DMR are immune from ABA corruption -- there can be
4637 // multiple concurrent pushers, but only one popper or detacher.
4638 // This implementation pops from the head of the list. This is unfair,
4639 // but tends to provide excellent throughput as hot threads remain hot.
4640 // (We wake recently run threads first).
4641 //
4642 // All paths through muxRelease() will execute a CAS.
4643 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4644 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4645 // executed within the critical section are complete and globally visible before the
4646 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4647 void Thread::muxRelease(volatile intptr_t * Lock) {
4648 for (;;) {
4649 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4650 assert(w & LOCKBIT, "invariant");
4651 if (w == LOCKBIT) return;
4652 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4653 assert(List != NULL, "invariant");
4654 assert(List->OnList == intptr_t(Lock), "invariant");
4655 ParkEvent * const nxt = List->ListNext;
4656 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4657
4658 // The following CAS() releases the lock and pops the head element.
4659 // The CAS() also ratifies the previously fetched lock-word value.
4660 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4661 continue;
4662 }
4663 List->OnList = 0;
4664 OrderAccess::fence();
4665 List->unpark();
4666 return;
4667 }
4668 }
4669
4670
4671 void Threads::verify() {
4672 ALL_JAVA_THREADS(p) {
4673 p->verify();
4674 }
4675 VMThread* thread = VMThread::vm_thread();
4676 if (thread != NULL) thread->verify();
4677 }