1 /*
2 * Copyright (c) 1997, 2014, 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/scopeDesc.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "interpreter/linkResolver.hpp"
35 #include "interpreter/oopMapCache.hpp"
36 #include "jvmtifiles/jvmtiEnv.hpp"
37 #include "memory/gcLocker.inline.hpp"
38 #include "memory/metaspaceShared.hpp"
39 #include "memory/oopFactory.hpp"
40 #include "memory/universe.inline.hpp"
41 #include "oops/instanceKlass.hpp"
42 #include "oops/objArrayOop.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "oops/symbol.hpp"
45 #include "prims/jvm_misc.hpp"
46 #include "prims/jvmtiExport.hpp"
47 #include "prims/jvmtiThreadState.hpp"
48 #include "prims/privilegedStack.hpp"
49 #include "runtime/arguments.hpp"
50 #include "runtime/atomic.inline.hpp"
51 #include "runtime/biasedLocking.hpp"
52 #include "runtime/deoptimization.hpp"
53 #include "runtime/fprofiler.hpp"
54 #include "runtime/frame.inline.hpp"
55 #include "runtime/init.hpp"
56 #include "runtime/interfaceSupport.hpp"
57 #include "runtime/java.hpp"
58 #include "runtime/javaCalls.hpp"
59 #include "runtime/jniPeriodicChecker.hpp"
60 #include "runtime/memprofiler.hpp"
61 #include "runtime/mutexLocker.hpp"
62 #include "runtime/objectMonitor.hpp"
63 #include "runtime/orderAccess.inline.hpp"
64 #include "runtime/osThread.hpp"
65 #include "runtime/safepoint.hpp"
66 #include "runtime/sharedRuntime.hpp"
67 #include "runtime/statSampler.hpp"
68 #include "runtime/stubRoutines.hpp"
69 #include "runtime/sweeper.hpp"
70 #include "runtime/task.hpp"
71 #include "runtime/thread.inline.hpp"
72 #include "runtime/threadCritical.hpp"
73 #include "runtime/threadLocalStorage.hpp"
74 #include "runtime/vframe.hpp"
75 #include "runtime/vframeArray.hpp"
76 #include "runtime/vframe_hp.hpp"
77 #include "runtime/vmThread.hpp"
78 #include "runtime/vm_operations.hpp"
79 #include "runtime/vm_version.hpp"
80 #include "services/attachListener.hpp"
81 #include "services/management.hpp"
82 #include "services/memTracker.hpp"
83 #include "services/threadService.hpp"
84 #include "trace/tracing.hpp"
85 #include "trace/traceMacros.hpp"
86 #include "utilities/defaultStream.hpp"
87 #include "utilities/dtrace.hpp"
88 #include "utilities/events.hpp"
89 #include "utilities/preserveException.hpp"
90 #include "utilities/macros.hpp"
91 #if INCLUDE_ALL_GCS
92 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
93 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
94 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
95 #endif // INCLUDE_ALL_GCS
96 #ifdef COMPILER1
97 #include "c1/c1_Compiler.hpp"
98 #endif
99 #ifdef COMPILER2
100 #include "opto/c2compiler.hpp"
101 #include "opto/idealGraphPrinter.hpp"
102 #endif
103 #if INCLUDE_RTM_OPT
104 #include "runtime/rtmLocking.hpp"
105 #endif
106
107 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
108
109 #ifdef DTRACE_ENABLED
110
111 // Only bother with this argument setup if dtrace is available
112
113 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
114 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
115
116 #define DTRACE_THREAD_PROBE(probe, javathread) \
117 { \
118 ResourceMark rm(this); \
119 int len = 0; \
120 const char* name = (javathread)->get_thread_name(); \
121 len = strlen(name); \
122 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
123 (char *) name, len, \
124 java_lang_Thread::thread_id((javathread)->threadObj()), \
125 (uintptr_t) (javathread)->osthread()->thread_id(), \
126 java_lang_Thread::is_daemon((javathread)->threadObj())); \
127 }
128
129 #else // ndef DTRACE_ENABLED
130
131 #define DTRACE_THREAD_PROBE(probe, javathread)
132
133 #endif // ndef DTRACE_ENABLED
134
135
136 // Class hierarchy
137 // - Thread
138 // - VMThread
139 // - WatcherThread
140 // - ConcurrentMarkSweepThread
141 // - JavaThread
142 // - CompilerThread
143
144 // ======= Thread ========
145 // Support for forcing alignment of thread objects for biased locking
146 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
147 if (UseBiasedLocking) {
148 const int alignment = markOopDesc::biased_lock_alignment;
149 size_t aligned_size = size + (alignment - sizeof(intptr_t));
150 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
151 : AllocateHeap(aligned_size, flags, CURRENT_PC,
152 AllocFailStrategy::RETURN_NULL);
153 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
154 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
155 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
156 "JavaThread alignment code overflowed allocated storage");
157 if (TraceBiasedLocking) {
158 if (aligned_addr != real_malloc_addr) {
159 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
160 real_malloc_addr, aligned_addr);
161 }
162 }
163 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
164 return aligned_addr;
165 } else {
166 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
167 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
168 }
169 }
170
171 void Thread::operator delete(void* p) {
172 if (UseBiasedLocking) {
173 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
174 FreeHeap(real_malloc_addr);
175 } else {
176 FreeHeap(p);
177 }
178 }
179
180
181 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
182 // JavaThread
183
184
185 Thread::Thread() {
186 // stack and get_thread
187 set_stack_base(NULL);
188 set_stack_size(0);
189 set_self_raw_id(0);
190 set_lgrp_id(-1);
191
192 // allocated data structures
193 set_osthread(NULL);
194 set_resource_area(new (mtThread)ResourceArea());
195 DEBUG_ONLY(_current_resource_mark = NULL;)
196 set_handle_area(new (mtThread) HandleArea(NULL));
197 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
198 set_active_handles(NULL);
199 set_free_handle_block(NULL);
200 set_last_handle_mark(NULL);
201
202 // This initial value ==> never claimed.
203 _oops_do_parity = 0;
204
205 _metadata_on_stack_buffer = NULL;
206
207 // the handle mark links itself to last_handle_mark
208 new HandleMark(this);
209
210 // plain initialization
211 debug_only(_owned_locks = NULL;)
212 debug_only(_allow_allocation_count = 0;)
213 NOT_PRODUCT(_allow_safepoint_count = 0;)
214 NOT_PRODUCT(_skip_gcalot = false;)
215 _jvmti_env_iteration_count = 0;
216 set_allocated_bytes(0);
217 _vm_operation_started_count = 0;
218 _vm_operation_completed_count = 0;
219 _current_pending_monitor = NULL;
220 _current_pending_monitor_is_from_java = true;
221 _current_waiting_monitor = NULL;
222 _num_nested_signal = 0;
223 omFreeList = NULL;
224 omFreeCount = 0;
225 omFreeProvision = 32;
226 omInUseList = NULL;
227 omInUseCount = 0;
228
229 #ifdef ASSERT
230 _visited_for_critical_count = false;
231 #endif
232
233 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
234 _suspend_flags = 0;
235
236 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
237 _hashStateX = os::random();
238 _hashStateY = 842502087;
239 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
240 _hashStateW = 273326509;
241
242 _OnTrap = 0;
243 _schedctl = NULL;
244 _Stalled = 0;
245 _TypeTag = 0x2BAD;
246
247 // Many of the following fields are effectively final - immutable
248 // Note that nascent threads can't use the Native Monitor-Mutex
249 // construct until the _MutexEvent is initialized ...
250 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
251 // we might instead use a stack of ParkEvents that we could provision on-demand.
252 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
253 // and ::Release()
254 _ParkEvent = ParkEvent::Allocate(this);
255 _SleepEvent = ParkEvent::Allocate(this);
256 _MutexEvent = ParkEvent::Allocate(this);
257 _MuxEvent = ParkEvent::Allocate(this);
258
259 #ifdef CHECK_UNHANDLED_OOPS
260 if (CheckUnhandledOops) {
261 _unhandled_oops = new UnhandledOops(this);
262 }
263 #endif // CHECK_UNHANDLED_OOPS
264 #ifdef ASSERT
265 if (UseBiasedLocking) {
266 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
267 assert(this == _real_malloc_address ||
268 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
269 "bug in forced alignment of thread objects");
270 }
271 #endif // ASSERT
272 }
273
274 void Thread::initialize_thread_local_storage() {
275 // Note: Make sure this method only calls
276 // non-blocking operations. Otherwise, it might not work
277 // with the thread-startup/safepoint interaction.
278
279 // During Java thread startup, safepoint code should allow this
280 // method to complete because it may need to allocate memory to
281 // store information for the new thread.
282
283 // initialize structure dependent on thread local storage
284 ThreadLocalStorage::set_thread(this);
285 }
286
287 void Thread::record_stack_base_and_size() {
288 set_stack_base(os::current_stack_base());
289 set_stack_size(os::current_stack_size());
290 if (is_Java_thread()) {
291 ((JavaThread*) this)->set_stack_overflow_limit();
292 }
293 // CR 7190089: on Solaris, primordial thread's stack is adjusted
294 // in initialize_thread(). Without the adjustment, stack size is
295 // incorrect if stack is set to unlimited (ulimit -s unlimited).
296 // So far, only Solaris has real implementation of initialize_thread().
297 //
298 // set up any platform-specific state.
299 os::initialize_thread(this);
300
301 #if INCLUDE_NMT
302 // record thread's native stack, stack grows downward
303 address stack_low_addr = stack_base() - stack_size();
304 MemTracker::record_thread_stack(stack_low_addr, stack_size());
305 #endif // INCLUDE_NMT
306 }
307
308
309 Thread::~Thread() {
310 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
311 ObjectSynchronizer::omFlush(this);
312
313 EVENT_THREAD_DESTRUCT(this);
314
315 // stack_base can be NULL if the thread is never started or exited before
316 // record_stack_base_and_size called. Although, we would like to ensure
317 // that all started threads do call record_stack_base_and_size(), there is
318 // not proper way to enforce that.
319 #if INCLUDE_NMT
320 if (_stack_base != NULL) {
321 address low_stack_addr = stack_base() - stack_size();
322 MemTracker::release_thread_stack(low_stack_addr, stack_size());
323 #ifdef ASSERT
324 set_stack_base(NULL);
325 #endif
326 }
327 #endif // INCLUDE_NMT
328
329 // deallocate data structures
330 delete resource_area();
331 // since the handle marks are using the handle area, we have to deallocated the root
332 // handle mark before deallocating the thread's handle area,
333 assert(last_handle_mark() != NULL, "check we have an element");
334 delete last_handle_mark();
335 assert(last_handle_mark() == NULL, "check we have reached the end");
336
337 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
338 // We NULL out the fields for good hygiene.
339 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
340 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
341 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
342 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
343
344 delete handle_area();
345 delete metadata_handles();
346
347 // osthread() can be NULL, if creation of thread failed.
348 if (osthread() != NULL) os::free_thread(osthread());
349
350 delete _SR_lock;
351
352 // clear thread local storage if the Thread is deleting itself
353 if (this == Thread::current()) {
354 ThreadLocalStorage::set_thread(NULL);
355 } else {
356 // In the case where we're not the current thread, invalidate all the
357 // caches in case some code tries to get the current thread or the
358 // thread that was destroyed, and gets stale information.
359 ThreadLocalStorage::invalidate_all();
360 }
361 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
362 }
363
364 // NOTE: dummy function for assertion purpose.
365 void Thread::run() {
366 ShouldNotReachHere();
367 }
368
369 #ifdef ASSERT
370 // Private method to check for dangling thread pointer
371 void check_for_dangling_thread_pointer(Thread *thread) {
372 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
373 "possibility of dangling Thread pointer");
374 }
375 #endif
376
377 ThreadPriority Thread::get_priority(const Thread* const thread) {
378 ThreadPriority priority;
379 // Can return an error!
380 (void)os::get_priority(thread, priority);
381 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
382 return priority;
383 }
384
385 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
386 debug_only(check_for_dangling_thread_pointer(thread);)
387 // Can return an error!
388 (void)os::set_priority(thread, priority);
389 }
390
391
392 void Thread::start(Thread* thread) {
393 // Start is different from resume in that its safety is guaranteed by context or
394 // being called from a Java method synchronized on the Thread object.
395 if (!DisableStartThread) {
396 if (thread->is_Java_thread()) {
397 // Initialize the thread state to RUNNABLE before starting this thread.
398 // Can not set it after the thread started because we do not know the
399 // exact thread state at that time. It could be in MONITOR_WAIT or
400 // in SLEEPING or some other state.
401 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
402 java_lang_Thread::RUNNABLE);
403 }
404 os::start_thread(thread);
405 }
406 }
407
408 // Enqueue a VM_Operation to do the job for us - sometime later
409 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
410 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
411 VMThread::execute(vm_stop);
412 }
413
414
415 // Check if an external suspend request has completed (or has been
416 // cancelled). Returns true if the thread is externally suspended and
417 // false otherwise.
418 //
419 // The bits parameter returns information about the code path through
420 // the routine. Useful for debugging:
421 //
422 // set in is_ext_suspend_completed():
423 // 0x00000001 - routine was entered
424 // 0x00000010 - routine return false at end
425 // 0x00000100 - thread exited (return false)
426 // 0x00000200 - suspend request cancelled (return false)
427 // 0x00000400 - thread suspended (return true)
428 // 0x00001000 - thread is in a suspend equivalent state (return true)
429 // 0x00002000 - thread is native and walkable (return true)
430 // 0x00004000 - thread is native_trans and walkable (needed retry)
431 //
432 // set in wait_for_ext_suspend_completion():
433 // 0x00010000 - routine was entered
434 // 0x00020000 - suspend request cancelled before loop (return false)
435 // 0x00040000 - thread suspended before loop (return true)
436 // 0x00080000 - suspend request cancelled in loop (return false)
437 // 0x00100000 - thread suspended in loop (return true)
438 // 0x00200000 - suspend not completed during retry loop (return false)
439
440 // Helper class for tracing suspend wait debug bits.
441 //
442 // 0x00000100 indicates that the target thread exited before it could
443 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
444 // 0x00080000 each indicate a cancelled suspend request so they don't
445 // count as wait failures either.
446 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
447
448 class TraceSuspendDebugBits : public StackObj {
449 private:
450 JavaThread * jt;
451 bool is_wait;
452 bool called_by_wait; // meaningful when !is_wait
453 uint32_t * bits;
454
455 public:
456 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
457 uint32_t *_bits) {
458 jt = _jt;
459 is_wait = _is_wait;
460 called_by_wait = _called_by_wait;
461 bits = _bits;
462 }
463
464 ~TraceSuspendDebugBits() {
465 if (!is_wait) {
466 #if 1
467 // By default, don't trace bits for is_ext_suspend_completed() calls.
468 // That trace is very chatty.
469 return;
470 #else
471 if (!called_by_wait) {
472 // If tracing for is_ext_suspend_completed() is enabled, then only
473 // trace calls to it from wait_for_ext_suspend_completion()
474 return;
475 }
476 #endif
477 }
478
479 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
480 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
481 MutexLocker ml(Threads_lock); // needed for get_thread_name()
482 ResourceMark rm;
483
484 tty->print_cr(
485 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
486 jt->get_thread_name(), *bits);
487
488 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
489 }
490 }
491 }
492 };
493 #undef DEBUG_FALSE_BITS
494
495
496 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
497 uint32_t *bits) {
498 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
499
500 bool did_trans_retry = false; // only do thread_in_native_trans retry once
501 bool do_trans_retry; // flag to force the retry
502
503 *bits |= 0x00000001;
504
505 do {
506 do_trans_retry = false;
507
508 if (is_exiting()) {
509 // Thread is in the process of exiting. This is always checked
510 // first to reduce the risk of dereferencing a freed JavaThread.
511 *bits |= 0x00000100;
512 return false;
513 }
514
515 if (!is_external_suspend()) {
516 // Suspend request is cancelled. This is always checked before
517 // is_ext_suspended() to reduce the risk of a rogue resume
518 // confusing the thread that made the suspend request.
519 *bits |= 0x00000200;
520 return false;
521 }
522
523 if (is_ext_suspended()) {
524 // thread is suspended
525 *bits |= 0x00000400;
526 return true;
527 }
528
529 // Now that we no longer do hard suspends of threads running
530 // native code, the target thread can be changing thread state
531 // while we are in this routine:
532 //
533 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
534 //
535 // We save a copy of the thread state as observed at this moment
536 // and make our decision about suspend completeness based on the
537 // copy. This closes the race where the thread state is seen as
538 // _thread_in_native_trans in the if-thread_blocked check, but is
539 // seen as _thread_blocked in if-thread_in_native_trans check.
540 JavaThreadState save_state = thread_state();
541
542 if (save_state == _thread_blocked && is_suspend_equivalent()) {
543 // If the thread's state is _thread_blocked and this blocking
544 // condition is known to be equivalent to a suspend, then we can
545 // consider the thread to be externally suspended. This means that
546 // the code that sets _thread_blocked has been modified to do
547 // self-suspension if the blocking condition releases. We also
548 // used to check for CONDVAR_WAIT here, but that is now covered by
549 // the _thread_blocked with self-suspension check.
550 //
551 // Return true since we wouldn't be here unless there was still an
552 // external suspend request.
553 *bits |= 0x00001000;
554 return true;
555 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
556 // Threads running native code will self-suspend on native==>VM/Java
557 // transitions. If its stack is walkable (should always be the case
558 // unless this function is called before the actual java_suspend()
559 // call), then the wait is done.
560 *bits |= 0x00002000;
561 return true;
562 } else if (!called_by_wait && !did_trans_retry &&
563 save_state == _thread_in_native_trans &&
564 frame_anchor()->walkable()) {
565 // The thread is transitioning from thread_in_native to another
566 // thread state. check_safepoint_and_suspend_for_native_trans()
567 // will force the thread to self-suspend. If it hasn't gotten
568 // there yet we may have caught the thread in-between the native
569 // code check above and the self-suspend. Lucky us. If we were
570 // called by wait_for_ext_suspend_completion(), then it
571 // will be doing the retries so we don't have to.
572 //
573 // Since we use the saved thread state in the if-statement above,
574 // there is a chance that the thread has already transitioned to
575 // _thread_blocked by the time we get here. In that case, we will
576 // make a single unnecessary pass through the logic below. This
577 // doesn't hurt anything since we still do the trans retry.
578
579 *bits |= 0x00004000;
580
581 // Once the thread leaves thread_in_native_trans for another
582 // thread state, we break out of this retry loop. We shouldn't
583 // need this flag to prevent us from getting back here, but
584 // sometimes paranoia is good.
585 did_trans_retry = true;
586
587 // We wait for the thread to transition to a more usable state.
588 for (int i = 1; i <= SuspendRetryCount; i++) {
589 // We used to do an "os::yield_all(i)" call here with the intention
590 // that yielding would increase on each retry. However, the parameter
591 // is ignored on Linux which means the yield didn't scale up. Waiting
592 // on the SR_lock below provides a much more predictable scale up for
593 // the delay. It also provides a simple/direct point to check for any
594 // safepoint requests from the VMThread
595
596 // temporarily drops SR_lock while doing wait with safepoint check
597 // (if we're a JavaThread - the WatcherThread can also call this)
598 // and increase delay with each retry
599 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
600
601 // check the actual thread state instead of what we saved above
602 if (thread_state() != _thread_in_native_trans) {
603 // the thread has transitioned to another thread state so
604 // try all the checks (except this one) one more time.
605 do_trans_retry = true;
606 break;
607 }
608 } // end retry loop
609
610
611 }
612 } while (do_trans_retry);
613
614 *bits |= 0x00000010;
615 return false;
616 }
617
618 // Wait for an external suspend request to complete (or be cancelled).
619 // Returns true if the thread is externally suspended and false otherwise.
620 //
621 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
622 uint32_t *bits) {
623 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
624 false /* !called_by_wait */, bits);
625
626 // local flag copies to minimize SR_lock hold time
627 bool is_suspended;
628 bool pending;
629 uint32_t reset_bits;
630
631 // set a marker so is_ext_suspend_completed() knows we are the caller
632 *bits |= 0x00010000;
633
634 // We use reset_bits to reinitialize the bits value at the top of
635 // each retry loop. This allows the caller to make use of any
636 // unused bits for their own marking purposes.
637 reset_bits = *bits;
638
639 {
640 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
641 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
642 delay, bits);
643 pending = is_external_suspend();
644 }
645 // must release SR_lock to allow suspension to complete
646
647 if (!pending) {
648 // A cancelled suspend request is the only false return from
649 // is_ext_suspend_completed() that keeps us from entering the
650 // retry loop.
651 *bits |= 0x00020000;
652 return false;
653 }
654
655 if (is_suspended) {
656 *bits |= 0x00040000;
657 return true;
658 }
659
660 for (int i = 1; i <= retries; i++) {
661 *bits = reset_bits; // reinit to only track last retry
662
663 // We used to do an "os::yield_all(i)" call here with the intention
664 // that yielding would increase on each retry. However, the parameter
665 // is ignored on Linux which means the yield didn't scale up. Waiting
666 // on the SR_lock below provides a much more predictable scale up for
667 // the delay. It also provides a simple/direct point to check for any
668 // safepoint requests from the VMThread
669
670 {
671 MutexLocker ml(SR_lock());
672 // wait with safepoint check (if we're a JavaThread - the WatcherThread
673 // can also call this) and increase delay with each retry
674 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
675
676 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
677 delay, bits);
678
679 // It is possible for the external suspend request to be cancelled
680 // (by a resume) before the actual suspend operation is completed.
681 // Refresh our local copy to see if we still need to wait.
682 pending = is_external_suspend();
683 }
684
685 if (!pending) {
686 // A cancelled suspend request is the only false return from
687 // is_ext_suspend_completed() that keeps us from staying in the
688 // retry loop.
689 *bits |= 0x00080000;
690 return false;
691 }
692
693 if (is_suspended) {
694 *bits |= 0x00100000;
695 return true;
696 }
697 } // end retry loop
698
699 // thread did not suspend after all our retries
700 *bits |= 0x00200000;
701 return false;
702 }
703
704 #ifndef PRODUCT
705 void JavaThread::record_jump(address target, address instr, const char* file,
706 int line) {
707
708 // This should not need to be atomic as the only way for simultaneous
709 // updates is via interrupts. Even then this should be rare or non-existent
710 // and we don't care that much anyway.
711
712 int index = _jmp_ring_index;
713 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
714 _jmp_ring[index]._target = (intptr_t) target;
715 _jmp_ring[index]._instruction = (intptr_t) instr;
716 _jmp_ring[index]._file = file;
717 _jmp_ring[index]._line = line;
718 }
719 #endif // PRODUCT
720
721 // Called by flat profiler
722 // Callers have already called wait_for_ext_suspend_completion
723 // The assertion for that is currently too complex to put here:
724 bool JavaThread::profile_last_Java_frame(frame* _fr) {
725 bool gotframe = false;
726 // self suspension saves needed state.
727 if (has_last_Java_frame() && _anchor.walkable()) {
728 *_fr = pd_last_frame();
729 gotframe = true;
730 }
731 return gotframe;
732 }
733
734 void Thread::interrupt(Thread* thread) {
735 debug_only(check_for_dangling_thread_pointer(thread);)
736 os::interrupt(thread);
737 }
738
739 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
740 debug_only(check_for_dangling_thread_pointer(thread);)
741 // Note: If clear_interrupted==false, this simply fetches and
742 // returns the value of the field osthread()->interrupted().
743 return os::is_interrupted(thread, clear_interrupted);
744 }
745
746
747 // GC Support
748 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
749 jint thread_parity = _oops_do_parity;
750 if (thread_parity != strong_roots_parity) {
751 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
752 if (res == thread_parity) {
753 return true;
754 } else {
755 guarantee(res == strong_roots_parity, "Or else what?");
756 assert(SharedHeap::heap()->workers()->active_workers() > 0,
757 "Should only fail when parallel.");
758 return false;
759 }
760 }
761 assert(SharedHeap::heap()->workers()->active_workers() > 0,
762 "Should only fail when parallel.");
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_do(void f(Metadata*)) {
778 if (metadata_handles() != NULL) {
779 for (int i = 0; i< metadata_handles()->length(); i++) {
780 f(metadata_handles()->at(i));
781 }
782 }
783 }
784
785 void Thread::print_on(outputStream* st) const {
786 // get_priority assumes osthread initialized
787 if (osthread() != NULL) {
788 int os_prio;
789 if (os::get_native_priority(this, &os_prio) == OS_OK) {
790 st->print("os_prio=%d ", os_prio);
791 }
792 st->print("tid=" INTPTR_FORMAT " ", this);
793 ext().print_on(st);
794 osthread()->print_on(st);
795 }
796 debug_only(if (WizardMode) print_owned_locks_on(st);)
797 }
798
799 // Thread::print_on_error() is called by fatal error handler. Don't use
800 // any lock or allocate memory.
801 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
802 if (is_VM_thread()) st->print("VMThread");
803 else if (is_Compiler_thread()) st->print("CompilerThread");
804 else if (is_Java_thread()) st->print("JavaThread");
805 else if (is_GC_task_thread()) st->print("GCTaskThread");
806 else if (is_Watcher_thread()) st->print("WatcherThread");
807 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
808 else st->print("Thread");
809
810 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
811 _stack_base - _stack_size, _stack_base);
812
813 if (osthread()) {
814 st->print(" [id=%d]", osthread()->thread_id());
815 }
816 }
817
818 #ifdef ASSERT
819 void Thread::print_owned_locks_on(outputStream* st) const {
820 Monitor *cur = _owned_locks;
821 if (cur == NULL) {
822 st->print(" (no locks) ");
823 } else {
824 st->print_cr(" Locks owned:");
825 while (cur) {
826 cur->print_on(st);
827 cur = cur->next();
828 }
829 }
830 }
831
832 static int ref_use_count = 0;
833
834 bool Thread::owns_locks_but_compiled_lock() const {
835 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
836 if (cur != Compile_lock) return true;
837 }
838 return false;
839 }
840
841
842 #endif
843
844 #ifndef PRODUCT
845
846 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
847 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
848 // no threads which allow_vm_block's are held
849 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
850 // Check if current thread is allowed to block at a safepoint
851 if (!(_allow_safepoint_count == 0)) {
852 fatal("Possible safepoint reached by thread that does not allow it");
853 }
854 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
855 fatal("LEAF method calling lock?");
856 }
857
858 #ifdef ASSERT
859 if (potential_vm_operation && is_Java_thread()
860 && !Universe::is_bootstrapping()) {
861 // Make sure we do not hold any locks that the VM thread also uses.
862 // This could potentially lead to deadlocks
863 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
864 // Threads_lock is special, since the safepoint synchronization will not start before this is
865 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
866 // since it is used to transfer control between JavaThreads and the VMThread
867 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
868 if ((cur->allow_vm_block() &&
869 cur != Threads_lock &&
870 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
871 cur != VMOperationRequest_lock &&
872 cur != VMOperationQueue_lock) ||
873 cur->rank() == Mutex::special) {
874 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
875 }
876 }
877 }
878
879 if (GCALotAtAllSafepoints) {
880 // We could enter a safepoint here and thus have a gc
881 InterfaceSupport::check_gc_alot();
882 }
883 #endif
884 }
885 #endif
886
887 bool Thread::is_in_stack(address adr) const {
888 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
889 address end = os::current_stack_pointer();
890 // Allow non Java threads to call this without stack_base
891 if (_stack_base == NULL) return true;
892 if (stack_base() >= adr && adr >= end) return true;
893
894 return false;
895 }
896
897
898 bool Thread::is_in_usable_stack(address adr) const {
899 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
900 size_t usable_stack_size = _stack_size - stack_guard_size;
901
902 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
903 }
904
905
906 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
907 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
908 // used for compilation in the future. If that change is made, the need for these methods
909 // should be revisited, and they should be removed if possible.
910
911 bool Thread::is_lock_owned(address adr) const {
912 return on_local_stack(adr);
913 }
914
915 bool Thread::set_as_starting_thread() {
916 // NOTE: this must be called inside the main thread.
917 return os::create_main_thread((JavaThread*)this);
918 }
919
920 static void initialize_class(Symbol* class_name, TRAPS) {
921 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
922 InstanceKlass::cast(klass)->initialize(CHECK);
923 }
924
925
926 // Creates the initial ThreadGroup
927 static Handle create_initial_thread_group(TRAPS) {
928 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
929 instanceKlassHandle klass (THREAD, k);
930
931 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
932 {
933 JavaValue result(T_VOID);
934 JavaCalls::call_special(&result,
935 system_instance,
936 klass,
937 vmSymbols::object_initializer_name(),
938 vmSymbols::void_method_signature(),
939 CHECK_NH);
940 }
941 Universe::set_system_thread_group(system_instance());
942
943 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
944 {
945 JavaValue result(T_VOID);
946 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
947 JavaCalls::call_special(&result,
948 main_instance,
949 klass,
950 vmSymbols::object_initializer_name(),
951 vmSymbols::threadgroup_string_void_signature(),
952 system_instance,
953 string,
954 CHECK_NH);
955 }
956 return main_instance;
957 }
958
959 // Creates the initial Thread
960 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
961 TRAPS) {
962 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
963 instanceKlassHandle klass (THREAD, k);
964 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
965
966 java_lang_Thread::set_thread(thread_oop(), thread);
967 java_lang_Thread::set_priority(thread_oop(), NormPriority);
968 thread->set_threadObj(thread_oop());
969
970 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
971
972 JavaValue result(T_VOID);
973 JavaCalls::call_special(&result, thread_oop,
974 klass,
975 vmSymbols::object_initializer_name(),
976 vmSymbols::threadgroup_string_void_signature(),
977 thread_group,
978 string,
979 CHECK_NULL);
980 return thread_oop();
981 }
982
983 static void call_initializeSystemClass(TRAPS) {
984 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
985 instanceKlassHandle klass (THREAD, k);
986
987 JavaValue result(T_VOID);
988 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
989 vmSymbols::void_method_signature(), CHECK);
990 }
991
992 char java_runtime_name[128] = "";
993 char java_runtime_version[128] = "";
994
995 // extract the JRE name from sun.misc.Version.java_runtime_name
996 static const char* get_java_runtime_name(TRAPS) {
997 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
998 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
999 fieldDescriptor fd;
1000 bool found = k != NULL &&
1001 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1002 vmSymbols::string_signature(), &fd);
1003 if (found) {
1004 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1005 if (name_oop == NULL) {
1006 return NULL;
1007 }
1008 const char* name = java_lang_String::as_utf8_string(name_oop,
1009 java_runtime_name,
1010 sizeof(java_runtime_name));
1011 return name;
1012 } else {
1013 return NULL;
1014 }
1015 }
1016
1017 // extract the JRE version from sun.misc.Version.java_runtime_version
1018 static const char* get_java_runtime_version(TRAPS) {
1019 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1020 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1021 fieldDescriptor fd;
1022 bool found = k != NULL &&
1023 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1024 vmSymbols::string_signature(), &fd);
1025 if (found) {
1026 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1027 if (name_oop == NULL) {
1028 return NULL;
1029 }
1030 const char* name = java_lang_String::as_utf8_string(name_oop,
1031 java_runtime_version,
1032 sizeof(java_runtime_version));
1033 return name;
1034 } else {
1035 return NULL;
1036 }
1037 }
1038
1039 // General purpose hook into Java code, run once when the VM is initialized.
1040 // The Java library method itself may be changed independently from the VM.
1041 static void call_postVMInitHook(TRAPS) {
1042 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1043 instanceKlassHandle klass (THREAD, k);
1044 if (klass.not_null()) {
1045 JavaValue result(T_VOID);
1046 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1047 vmSymbols::void_method_signature(),
1048 CHECK);
1049 }
1050 }
1051
1052 static void reset_vm_info_property(TRAPS) {
1053 // the vm info string
1054 ResourceMark rm(THREAD);
1055 const char *vm_info = VM_Version::vm_info_string();
1056
1057 // java.lang.System class
1058 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1059 instanceKlassHandle klass (THREAD, k);
1060
1061 // setProperty arguments
1062 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1063 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1064
1065 // return value
1066 JavaValue r(T_OBJECT);
1067
1068 // public static String setProperty(String key, String value);
1069 JavaCalls::call_static(&r,
1070 klass,
1071 vmSymbols::setProperty_name(),
1072 vmSymbols::string_string_string_signature(),
1073 key_str,
1074 value_str,
1075 CHECK);
1076 }
1077
1078
1079 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name,
1080 bool daemon, TRAPS) {
1081 assert(thread_group.not_null(), "thread group should be specified");
1082 assert(threadObj() == NULL, "should only create Java thread object once");
1083
1084 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1085 instanceKlassHandle klass (THREAD, k);
1086 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1087
1088 java_lang_Thread::set_thread(thread_oop(), this);
1089 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1090 set_threadObj(thread_oop());
1091
1092 JavaValue result(T_VOID);
1093 if (thread_name != NULL) {
1094 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1095 // Thread gets assigned specified name and null target
1096 JavaCalls::call_special(&result,
1097 thread_oop,
1098 klass,
1099 vmSymbols::object_initializer_name(),
1100 vmSymbols::threadgroup_string_void_signature(),
1101 thread_group, // Argument 1
1102 name, // Argument 2
1103 THREAD);
1104 } else {
1105 // Thread gets assigned name "Thread-nnn" and null target
1106 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1107 JavaCalls::call_special(&result,
1108 thread_oop,
1109 klass,
1110 vmSymbols::object_initializer_name(),
1111 vmSymbols::threadgroup_runnable_void_signature(),
1112 thread_group, // Argument 1
1113 Handle(), // Argument 2
1114 THREAD);
1115 }
1116
1117
1118 if (daemon) {
1119 java_lang_Thread::set_daemon(thread_oop());
1120 }
1121
1122 if (HAS_PENDING_EXCEPTION) {
1123 return;
1124 }
1125
1126 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1127 Handle threadObj(this, this->threadObj());
1128
1129 JavaCalls::call_special(&result,
1130 thread_group,
1131 group,
1132 vmSymbols::add_method_name(),
1133 vmSymbols::thread_void_signature(),
1134 threadObj, // Arg 1
1135 THREAD);
1136
1137
1138 }
1139
1140 // NamedThread -- non-JavaThread subclasses with multiple
1141 // uniquely named instances should derive from this.
1142 NamedThread::NamedThread() : Thread() {
1143 _name = NULL;
1144 _processed_thread = NULL;
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::print_on(outputStream* st) const {
1165 st->print("\"%s\" ", name());
1166 Thread::print_on(st);
1167 st->cr();
1168 }
1169
1170
1171 // ======= WatcherThread ========
1172
1173 // The watcher thread exists to simulate timer interrupts. It should
1174 // be replaced by an abstraction over whatever native support for
1175 // timer interrupts exists on the platform.
1176
1177 WatcherThread* WatcherThread::_watcher_thread = NULL;
1178 bool WatcherThread::_startable = false;
1179 volatile bool WatcherThread::_should_terminate = false;
1180
1181 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1182 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1183 if (os::create_thread(this, os::watcher_thread)) {
1184 _watcher_thread = this;
1185
1186 // Set the watcher thread to the highest OS priority which should not be
1187 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1188 // is created. The only normal thread using this priority is the reference
1189 // handler thread, which runs for very short intervals only.
1190 // If the VMThread's priority is not lower than the WatcherThread profiling
1191 // will be inaccurate.
1192 os::set_priority(this, MaxPriority);
1193 if (!DisableStartThread) {
1194 os::start_thread(this);
1195 }
1196 }
1197 }
1198
1199 int WatcherThread::sleep() const {
1200 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1201
1202 // remaining will be zero if there are no tasks,
1203 // causing the WatcherThread to sleep until a task is
1204 // enrolled
1205 int remaining = PeriodicTask::time_to_wait();
1206 int time_slept = 0;
1207
1208 // we expect this to timeout - we only ever get unparked when
1209 // we should terminate or when a new task has been enrolled
1210 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1211
1212 jlong time_before_loop = os::javaTimeNanos();
1213
1214 for (;;) {
1215 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1216 jlong now = os::javaTimeNanos();
1217
1218 if (remaining == 0) {
1219 // if we didn't have any tasks we could have waited for a long time
1220 // consider the time_slept zero and reset time_before_loop
1221 time_slept = 0;
1222 time_before_loop = now;
1223 } else {
1224 // need to recalculate since we might have new tasks in _tasks
1225 time_slept = (int) ((now - time_before_loop) / 1000000);
1226 }
1227
1228 // Change to task list or spurious wakeup of some kind
1229 if (timedout || _should_terminate) {
1230 break;
1231 }
1232
1233 remaining = PeriodicTask::time_to_wait();
1234 if (remaining == 0) {
1235 // Last task was just disenrolled so loop around and wait until
1236 // another task gets enrolled
1237 continue;
1238 }
1239
1240 remaining -= time_slept;
1241 if (remaining <= 0) {
1242 break;
1243 }
1244 }
1245
1246 return time_slept;
1247 }
1248
1249 void WatcherThread::run() {
1250 assert(this == watcher_thread(), "just checking");
1251
1252 this->record_stack_base_and_size();
1253 this->initialize_thread_local_storage();
1254 this->set_native_thread_name(this->name());
1255 this->set_active_handles(JNIHandleBlock::allocate_block());
1256 while (!_should_terminate) {
1257 assert(watcher_thread() == Thread::current(), "thread consistency check");
1258 assert(watcher_thread() == this, "thread consistency check");
1259
1260 // Calculate how long it'll be until the next PeriodicTask work
1261 // should be done, and sleep that amount of time.
1262 int time_waited = sleep();
1263
1264 if (is_error_reported()) {
1265 // A fatal error has happened, the error handler(VMError::report_and_die)
1266 // should abort JVM after creating an error log file. However in some
1267 // rare cases, the error handler itself might deadlock. Here we try to
1268 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1269 //
1270 // This code is in WatcherThread because WatcherThread wakes up
1271 // periodically so the fatal error handler doesn't need to do anything;
1272 // also because the WatcherThread is less likely to crash than other
1273 // threads.
1274
1275 for (;;) {
1276 if (!ShowMessageBoxOnError
1277 && (OnError == NULL || OnError[0] == '\0')
1278 && Arguments::abort_hook() == NULL) {
1279 os::sleep(this, 2 * 60 * 1000, false);
1280 fdStream err(defaultStream::output_fd());
1281 err.print_raw_cr("# [ timer expired, abort... ]");
1282 // skip atexit/vm_exit/vm_abort hooks
1283 os::die();
1284 }
1285
1286 // Wake up 5 seconds later, the fatal handler may reset OnError or
1287 // ShowMessageBoxOnError when it is ready to abort.
1288 os::sleep(this, 5 * 1000, false);
1289 }
1290 }
1291
1292 PeriodicTask::real_time_tick(time_waited);
1293 }
1294
1295 // Signal that it is terminated
1296 {
1297 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1298 _watcher_thread = NULL;
1299 Terminator_lock->notify();
1300 }
1301
1302 // Thread destructor usually does this..
1303 ThreadLocalStorage::set_thread(NULL);
1304 }
1305
1306 void WatcherThread::start() {
1307 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1308
1309 if (watcher_thread() == NULL && _startable) {
1310 _should_terminate = false;
1311 // Create the single instance of WatcherThread
1312 new WatcherThread();
1313 }
1314 }
1315
1316 void WatcherThread::make_startable() {
1317 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1318 _startable = true;
1319 }
1320
1321 void WatcherThread::stop() {
1322 // Get the PeriodicTask_lock if we can. If we cannot, then the
1323 // WatcherThread is using it and we don't want to block on that lock
1324 // here because that might cause a safepoint deadlock depending on
1325 // what the current WatcherThread tasks are doing.
1326 bool have_lock = PeriodicTask_lock->try_lock();
1327
1328 _should_terminate = true;
1329 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1330
1331 if (have_lock) {
1332 WatcherThread* watcher = watcher_thread();
1333 if (watcher != NULL) {
1334 // If we managed to get the lock, then we should unpark the
1335 // WatcherThread so that it can see we want it to stop.
1336 watcher->unpark();
1337 }
1338
1339 PeriodicTask_lock->unlock();
1340 }
1341
1342 // it is ok to take late safepoints here, if needed
1343 MutexLocker mu(Terminator_lock);
1344
1345 while (watcher_thread() != NULL) {
1346 // This wait should make safepoint checks, wait without a timeout,
1347 // and wait as a suspend-equivalent condition.
1348 //
1349 // Note: If the FlatProfiler is running, then this thread is waiting
1350 // for the WatcherThread to terminate and the WatcherThread, via the
1351 // FlatProfiler task, is waiting for the external suspend request on
1352 // this thread to complete. wait_for_ext_suspend_completion() will
1353 // eventually timeout, but that takes time. Making this wait a
1354 // suspend-equivalent condition solves that timeout problem.
1355 //
1356 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1357 Mutex::_as_suspend_equivalent_flag);
1358 }
1359 }
1360
1361 void WatcherThread::unpark() {
1362 MutexLockerEx ml(PeriodicTask_lock->owned_by_self()
1363 ? NULL
1364 : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1365 PeriodicTask_lock->notify();
1366 }
1367
1368 void WatcherThread::print_on(outputStream* st) const {
1369 st->print("\"%s\" ", name());
1370 Thread::print_on(st);
1371 st->cr();
1372 }
1373
1374 // ======= JavaThread ========
1375
1376 // A JavaThread is a normal Java thread
1377
1378 void JavaThread::initialize() {
1379 // Initialize fields
1380
1381 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1382 set_claimed_par_id(UINT_MAX);
1383
1384 set_saved_exception_pc(NULL);
1385 set_threadObj(NULL);
1386 _anchor.clear();
1387 set_entry_point(NULL);
1388 set_jni_functions(jni_functions());
1389 set_callee_target(NULL);
1390 set_vm_result(NULL);
1391 set_vm_result_2(NULL);
1392 set_vframe_array_head(NULL);
1393 set_vframe_array_last(NULL);
1394 set_deferred_locals(NULL);
1395 set_deopt_mark(NULL);
1396 set_deopt_nmethod(NULL);
1397 clear_must_deopt_id();
1398 set_monitor_chunks(NULL);
1399 set_next(NULL);
1400 set_thread_state(_thread_new);
1401 _terminated = _not_terminated;
1402 _privileged_stack_top = NULL;
1403 _array_for_gc = NULL;
1404 _suspend_equivalent = false;
1405 _in_deopt_handler = 0;
1406 _doing_unsafe_access = false;
1407 _stack_guard_state = stack_guard_unused;
1408 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1409 _exception_pc = 0;
1410 _exception_handler_pc = 0;
1411 _is_method_handle_return = 0;
1412 _jvmti_thread_state= NULL;
1413 _should_post_on_exceptions_flag = JNI_FALSE;
1414 _jvmti_get_loaded_classes_closure = NULL;
1415 _interp_only_mode = 0;
1416 _special_runtime_exit_condition = _no_async_condition;
1417 _pending_async_exception = NULL;
1418 _thread_stat = NULL;
1419 _thread_stat = new ThreadStatistics();
1420 _blocked_on_compilation = false;
1421 _jni_active_critical = 0;
1422 _pending_jni_exception_check_fn = NULL;
1423 _do_not_unlock_if_synchronized = false;
1424 _cached_monitor_info = NULL;
1425 _parker = Parker::Allocate(this);
1426
1427 #ifndef PRODUCT
1428 _jmp_ring_index = 0;
1429 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1430 record_jump(NULL, NULL, NULL, 0);
1431 }
1432 #endif // PRODUCT
1433
1434 set_thread_profiler(NULL);
1435 if (FlatProfiler::is_active()) {
1436 // This is where we would decide to either give each thread it's own profiler
1437 // or use one global one from FlatProfiler,
1438 // or up to some count of the number of profiled threads, etc.
1439 ThreadProfiler* pp = new ThreadProfiler();
1440 pp->engage();
1441 set_thread_profiler(pp);
1442 }
1443
1444 // Setup safepoint state info for this thread
1445 ThreadSafepointState::create(this);
1446
1447 debug_only(_java_call_counter = 0);
1448
1449 // JVMTI PopFrame support
1450 _popframe_condition = popframe_inactive;
1451 _popframe_preserved_args = NULL;
1452 _popframe_preserved_args_size = 0;
1453
1454 pd_initialize();
1455 }
1456
1457 #if INCLUDE_ALL_GCS
1458 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1459 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1460 #endif // INCLUDE_ALL_GCS
1461
1462 JavaThread::JavaThread(bool is_attaching_via_jni) :
1463 Thread()
1464 #if INCLUDE_ALL_GCS
1465 , _satb_mark_queue(&_satb_mark_queue_set),
1466 _dirty_card_queue(&_dirty_card_queue_set)
1467 #endif // INCLUDE_ALL_GCS
1468 {
1469 initialize();
1470 if (is_attaching_via_jni) {
1471 _jni_attach_state = _attaching_via_jni;
1472 } else {
1473 _jni_attach_state = _not_attaching_via_jni;
1474 }
1475 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1476 }
1477
1478 bool JavaThread::reguard_stack(address cur_sp) {
1479 if (_stack_guard_state != stack_guard_yellow_disabled) {
1480 return true; // Stack already guarded or guard pages not needed.
1481 }
1482
1483 if (register_stack_overflow()) {
1484 // For those architectures which have separate register and
1485 // memory stacks, we must check the register stack to see if
1486 // it has overflowed.
1487 return false;
1488 }
1489
1490 // Java code never executes within the yellow zone: the latter is only
1491 // there to provoke an exception during stack banging. If java code
1492 // is executing there, either StackShadowPages should be larger, or
1493 // some exception code in c1, c2 or the interpreter isn't unwinding
1494 // when it should.
1495 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1496
1497 enable_stack_yellow_zone();
1498 return true;
1499 }
1500
1501 bool JavaThread::reguard_stack(void) {
1502 return reguard_stack(os::current_stack_pointer());
1503 }
1504
1505
1506 void JavaThread::block_if_vm_exited() {
1507 if (_terminated == _vm_exited) {
1508 // _vm_exited is set at safepoint, and Threads_lock is never released
1509 // we will block here forever
1510 Threads_lock->lock_without_safepoint_check();
1511 ShouldNotReachHere();
1512 }
1513 }
1514
1515
1516 // Remove this ifdef when C1 is ported to the compiler interface.
1517 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1518 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1519
1520 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1521 Thread()
1522 #if INCLUDE_ALL_GCS
1523 , _satb_mark_queue(&_satb_mark_queue_set),
1524 _dirty_card_queue(&_dirty_card_queue_set)
1525 #endif // INCLUDE_ALL_GCS
1526 {
1527 initialize();
1528 _jni_attach_state = _not_attaching_via_jni;
1529 set_entry_point(entry_point);
1530 // Create the native thread itself.
1531 // %note runtime_23
1532 os::ThreadType thr_type = os::java_thread;
1533 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1534 os::java_thread;
1535 os::create_thread(this, thr_type, stack_sz);
1536 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1537 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1538 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1539 // the exception consists of creating the exception object & initializing it, initialization
1540 // will leave the VM via a JavaCall and then all locks must be unlocked).
1541 //
1542 // The thread is still suspended when we reach here. Thread must be explicit started
1543 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1544 // by calling Threads:add. The reason why this is not done here, is because the thread
1545 // object must be fully initialized (take a look at JVM_Start)
1546 }
1547
1548 JavaThread::~JavaThread() {
1549
1550 // JSR166 -- return the parker to the free list
1551 Parker::Release(_parker);
1552 _parker = NULL;
1553
1554 // Free any remaining previous UnrollBlock
1555 vframeArray* old_array = vframe_array_last();
1556
1557 if (old_array != NULL) {
1558 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1559 old_array->set_unroll_block(NULL);
1560 delete old_info;
1561 delete old_array;
1562 }
1563
1564 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1565 if (deferred != NULL) {
1566 // This can only happen if thread is destroyed before deoptimization occurs.
1567 assert(deferred->length() != 0, "empty array!");
1568 do {
1569 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1570 deferred->remove_at(0);
1571 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1572 delete dlv;
1573 } while (deferred->length() != 0);
1574 delete deferred;
1575 }
1576
1577 // All Java related clean up happens in exit
1578 ThreadSafepointState::destroy(this);
1579 if (_thread_profiler != NULL) delete _thread_profiler;
1580 if (_thread_stat != NULL) delete _thread_stat;
1581 }
1582
1583
1584 // The first routine called by a new Java thread
1585 void JavaThread::run() {
1586 // initialize thread-local alloc buffer related fields
1587 this->initialize_tlab();
1588
1589 // used to test validity of stack trace backs
1590 this->record_base_of_stack_pointer();
1591
1592 // Record real stack base and size.
1593 this->record_stack_base_and_size();
1594
1595 // Initialize thread local storage; set before calling MutexLocker
1596 this->initialize_thread_local_storage();
1597
1598 this->create_stack_guard_pages();
1599
1600 this->cache_global_variables();
1601
1602 // Thread is now sufficient initialized to be handled by the safepoint code as being
1603 // in the VM. Change thread state from _thread_new to _thread_in_vm
1604 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1605
1606 assert(JavaThread::current() == this, "sanity check");
1607 assert(!Thread::current()->owns_locks(), "sanity check");
1608
1609 DTRACE_THREAD_PROBE(start, this);
1610
1611 // This operation might block. We call that after all safepoint checks for a new thread has
1612 // been completed.
1613 this->set_active_handles(JNIHandleBlock::allocate_block());
1614
1615 if (JvmtiExport::should_post_thread_life()) {
1616 JvmtiExport::post_thread_start(this);
1617 }
1618
1619 EventThreadStart event;
1620 if (event.should_commit()) {
1621 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1622 event.commit();
1623 }
1624
1625 // We call another function to do the rest so we are sure that the stack addresses used
1626 // from there will be lower than the stack base just computed
1627 thread_main_inner();
1628
1629 // Note, thread is no longer valid at this point!
1630 }
1631
1632
1633 void JavaThread::thread_main_inner() {
1634 assert(JavaThread::current() == this, "sanity check");
1635 assert(this->threadObj() != NULL, "just checking");
1636
1637 // Execute thread entry point unless this thread has a pending exception
1638 // or has been stopped before starting.
1639 // Note: Due to JVM_StopThread we can have pending exceptions already!
1640 if (!this->has_pending_exception() &&
1641 !java_lang_Thread::is_stillborn(this->threadObj())) {
1642 {
1643 ResourceMark rm(this);
1644 this->set_native_thread_name(this->get_thread_name());
1645 }
1646 HandleMark hm(this);
1647 this->entry_point()(this, this);
1648 }
1649
1650 DTRACE_THREAD_PROBE(stop, this);
1651
1652 this->exit(false);
1653 delete this;
1654 }
1655
1656
1657 static void ensure_join(JavaThread* thread) {
1658 // We do not need to grap the Threads_lock, since we are operating on ourself.
1659 Handle threadObj(thread, thread->threadObj());
1660 assert(threadObj.not_null(), "java thread object must exist");
1661 ObjectLocker lock(threadObj, thread);
1662 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1663 thread->clear_pending_exception();
1664 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1665 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1666 // Clear the native thread instance - this makes isAlive return false and allows the join()
1667 // to complete once we've done the notify_all below
1668 java_lang_Thread::set_thread(threadObj(), NULL);
1669 lock.notify_all(thread);
1670 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1671 thread->clear_pending_exception();
1672 }
1673
1674
1675 // For any new cleanup additions, please check to see if they need to be applied to
1676 // cleanup_failed_attach_current_thread as well.
1677 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1678 assert(this == JavaThread::current(), "thread consistency check");
1679
1680 HandleMark hm(this);
1681 Handle uncaught_exception(this, this->pending_exception());
1682 this->clear_pending_exception();
1683 Handle threadObj(this, this->threadObj());
1684 assert(threadObj.not_null(), "Java thread object should be created");
1685
1686 if (get_thread_profiler() != NULL) {
1687 get_thread_profiler()->disengage();
1688 ResourceMark rm;
1689 get_thread_profiler()->print(get_thread_name());
1690 }
1691
1692
1693 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1694 {
1695 EXCEPTION_MARK;
1696
1697 CLEAR_PENDING_EXCEPTION;
1698 }
1699 if (!destroy_vm) {
1700 if (uncaught_exception.not_null()) {
1701 EXCEPTION_MARK;
1702 // Call method Thread.dispatchUncaughtException().
1703 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1704 JavaValue result(T_VOID);
1705 JavaCalls::call_virtual(&result,
1706 threadObj, thread_klass,
1707 vmSymbols::dispatchUncaughtException_name(),
1708 vmSymbols::throwable_void_signature(),
1709 uncaught_exception,
1710 THREAD);
1711 if (HAS_PENDING_EXCEPTION) {
1712 ResourceMark rm(this);
1713 jio_fprintf(defaultStream::error_stream(),
1714 "\nException: %s thrown from the UncaughtExceptionHandler"
1715 " in thread \"%s\"\n",
1716 pending_exception()->klass()->external_name(),
1717 get_thread_name());
1718 CLEAR_PENDING_EXCEPTION;
1719 }
1720 }
1721
1722 // Called before the java thread exit since we want to read info
1723 // from java_lang_Thread object
1724 EventThreadEnd event;
1725 if (event.should_commit()) {
1726 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1727 event.commit();
1728 }
1729
1730 // Call after last event on thread
1731 EVENT_THREAD_EXIT(this);
1732
1733 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1734 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1735 // is deprecated anyhow.
1736 if (!is_Compiler_thread()) {
1737 int count = 3;
1738 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1739 EXCEPTION_MARK;
1740 JavaValue result(T_VOID);
1741 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1742 JavaCalls::call_virtual(&result,
1743 threadObj, thread_klass,
1744 vmSymbols::exit_method_name(),
1745 vmSymbols::void_method_signature(),
1746 THREAD);
1747 CLEAR_PENDING_EXCEPTION;
1748 }
1749 }
1750 // notify JVMTI
1751 if (JvmtiExport::should_post_thread_life()) {
1752 JvmtiExport::post_thread_end(this);
1753 }
1754
1755 // We have notified the agents that we are exiting, before we go on,
1756 // we must check for a pending external suspend request and honor it
1757 // in order to not surprise the thread that made the suspend request.
1758 while (true) {
1759 {
1760 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1761 if (!is_external_suspend()) {
1762 set_terminated(_thread_exiting);
1763 ThreadService::current_thread_exiting(this);
1764 break;
1765 }
1766 // Implied else:
1767 // Things get a little tricky here. We have a pending external
1768 // suspend request, but we are holding the SR_lock so we
1769 // can't just self-suspend. So we temporarily drop the lock
1770 // and then self-suspend.
1771 }
1772
1773 ThreadBlockInVM tbivm(this);
1774 java_suspend_self();
1775
1776 // We're done with this suspend request, but we have to loop around
1777 // and check again. Eventually we will get SR_lock without a pending
1778 // external suspend request and will be able to mark ourselves as
1779 // exiting.
1780 }
1781 // no more external suspends are allowed at this point
1782 } else {
1783 // before_exit() has already posted JVMTI THREAD_END events
1784 }
1785
1786 // Notify waiters on thread object. This has to be done after exit() is called
1787 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1788 // group should have the destroyed bit set before waiters are notified).
1789 ensure_join(this);
1790 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1791
1792 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1793 // held by this thread must be released. A detach operation must only
1794 // get here if there are no Java frames on the stack. Therefore, any
1795 // owned monitors at this point MUST be JNI-acquired monitors which are
1796 // pre-inflated and in the monitor cache.
1797 //
1798 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1799 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1800 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1801 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1802 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1803 }
1804
1805 // These things needs to be done while we are still a Java Thread. Make sure that thread
1806 // is in a consistent state, in case GC happens
1807 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1808
1809 if (active_handles() != NULL) {
1810 JNIHandleBlock* block = active_handles();
1811 set_active_handles(NULL);
1812 JNIHandleBlock::release_block(block);
1813 }
1814
1815 if (free_handle_block() != NULL) {
1816 JNIHandleBlock* block = free_handle_block();
1817 set_free_handle_block(NULL);
1818 JNIHandleBlock::release_block(block);
1819 }
1820
1821 // These have to be removed while this is still a valid thread.
1822 remove_stack_guard_pages();
1823
1824 if (UseTLAB) {
1825 tlab().make_parsable(true); // retire TLAB
1826 }
1827
1828 if (JvmtiEnv::environments_might_exist()) {
1829 JvmtiExport::cleanup_thread(this);
1830 }
1831
1832 // We must flush any deferred card marks before removing a thread from
1833 // the list of active threads.
1834 Universe::heap()->flush_deferred_store_barrier(this);
1835 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1836
1837 #if INCLUDE_ALL_GCS
1838 // We must flush the G1-related buffers before removing a thread
1839 // from the list of active threads. We must do this after any deferred
1840 // card marks have been flushed (above) so that any entries that are
1841 // added to the thread's dirty card queue as a result are not lost.
1842 if (UseG1GC) {
1843 flush_barrier_queues();
1844 }
1845 #endif // INCLUDE_ALL_GCS
1846
1847 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1848 Threads::remove(this);
1849 }
1850
1851 #if INCLUDE_ALL_GCS
1852 // Flush G1-related queues.
1853 void JavaThread::flush_barrier_queues() {
1854 satb_mark_queue().flush();
1855 dirty_card_queue().flush();
1856 }
1857
1858 void JavaThread::initialize_queues() {
1859 assert(!SafepointSynchronize::is_at_safepoint(),
1860 "we should not be at a safepoint");
1861
1862 ObjPtrQueue& satb_queue = satb_mark_queue();
1863 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1864 // The SATB queue should have been constructed with its active
1865 // field set to false.
1866 assert(!satb_queue.is_active(), "SATB queue should not be active");
1867 assert(satb_queue.is_empty(), "SATB queue should be empty");
1868 // If we are creating the thread during a marking cycle, we should
1869 // set the active field of the SATB queue to true.
1870 if (satb_queue_set.is_active()) {
1871 satb_queue.set_active(true);
1872 }
1873
1874 DirtyCardQueue& dirty_queue = dirty_card_queue();
1875 // The dirty card queue should have been constructed with its
1876 // active field set to true.
1877 assert(dirty_queue.is_active(), "dirty card queue should be active");
1878 }
1879 #endif // INCLUDE_ALL_GCS
1880
1881 void JavaThread::cleanup_failed_attach_current_thread() {
1882 if (get_thread_profiler() != NULL) {
1883 get_thread_profiler()->disengage();
1884 ResourceMark rm;
1885 get_thread_profiler()->print(get_thread_name());
1886 }
1887
1888 if (active_handles() != NULL) {
1889 JNIHandleBlock* block = active_handles();
1890 set_active_handles(NULL);
1891 JNIHandleBlock::release_block(block);
1892 }
1893
1894 if (free_handle_block() != NULL) {
1895 JNIHandleBlock* block = free_handle_block();
1896 set_free_handle_block(NULL);
1897 JNIHandleBlock::release_block(block);
1898 }
1899
1900 // These have to be removed while this is still a valid thread.
1901 remove_stack_guard_pages();
1902
1903 if (UseTLAB) {
1904 tlab().make_parsable(true); // retire TLAB, if any
1905 }
1906
1907 #if INCLUDE_ALL_GCS
1908 if (UseG1GC) {
1909 flush_barrier_queues();
1910 }
1911 #endif // INCLUDE_ALL_GCS
1912
1913 Threads::remove(this);
1914 delete this;
1915 }
1916
1917
1918
1919
1920 JavaThread* JavaThread::active() {
1921 Thread* thread = ThreadLocalStorage::thread();
1922 assert(thread != NULL, "just checking");
1923 if (thread->is_Java_thread()) {
1924 return (JavaThread*) thread;
1925 } else {
1926 assert(thread->is_VM_thread(), "this must be a vm thread");
1927 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1928 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1929 assert(ret->is_Java_thread(), "must be a Java thread");
1930 return ret;
1931 }
1932 }
1933
1934 bool JavaThread::is_lock_owned(address adr) const {
1935 if (Thread::is_lock_owned(adr)) return true;
1936
1937 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1938 if (chunk->contains(adr)) return true;
1939 }
1940
1941 return false;
1942 }
1943
1944
1945 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1946 chunk->set_next(monitor_chunks());
1947 set_monitor_chunks(chunk);
1948 }
1949
1950 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1951 guarantee(monitor_chunks() != NULL, "must be non empty");
1952 if (monitor_chunks() == chunk) {
1953 set_monitor_chunks(chunk->next());
1954 } else {
1955 MonitorChunk* prev = monitor_chunks();
1956 while (prev->next() != chunk) prev = prev->next();
1957 prev->set_next(chunk->next());
1958 }
1959 }
1960
1961 // JVM support.
1962
1963 // Note: this function shouldn't block if it's called in
1964 // _thread_in_native_trans state (such as from
1965 // check_special_condition_for_native_trans()).
1966 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1967
1968 if (has_last_Java_frame() && has_async_condition()) {
1969 // If we are at a polling page safepoint (not a poll return)
1970 // then we must defer async exception because live registers
1971 // will be clobbered by the exception path. Poll return is
1972 // ok because the call we a returning from already collides
1973 // with exception handling registers and so there is no issue.
1974 // (The exception handling path kills call result registers but
1975 // this is ok since the exception kills the result anyway).
1976
1977 if (is_at_poll_safepoint()) {
1978 // if the code we are returning to has deoptimized we must defer
1979 // the exception otherwise live registers get clobbered on the
1980 // exception path before deoptimization is able to retrieve them.
1981 //
1982 RegisterMap map(this, false);
1983 frame caller_fr = last_frame().sender(&map);
1984 assert(caller_fr.is_compiled_frame(), "what?");
1985 if (caller_fr.is_deoptimized_frame()) {
1986 if (TraceExceptions) {
1987 ResourceMark rm;
1988 tty->print_cr("deferred async exception at compiled safepoint");
1989 }
1990 return;
1991 }
1992 }
1993 }
1994
1995 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
1996 if (condition == _no_async_condition) {
1997 // Conditions have changed since has_special_runtime_exit_condition()
1998 // was called:
1999 // - if we were here only because of an external suspend request,
2000 // then that was taken care of above (or cancelled) so we are done
2001 // - if we were here because of another async request, then it has
2002 // been cleared between the has_special_runtime_exit_condition()
2003 // and now so again we are done
2004 return;
2005 }
2006
2007 // Check for pending async. exception
2008 if (_pending_async_exception != NULL) {
2009 // Only overwrite an already pending exception, if it is not a threadDeath.
2010 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2011
2012 // We cannot call Exceptions::_throw(...) here because we cannot block
2013 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2014
2015 if (TraceExceptions) {
2016 ResourceMark rm;
2017 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2018 if (has_last_Java_frame()) {
2019 frame f = last_frame();
2020 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2021 }
2022 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2023 }
2024 _pending_async_exception = NULL;
2025 clear_has_async_exception();
2026 }
2027 }
2028
2029 if (check_unsafe_error &&
2030 condition == _async_unsafe_access_error && !has_pending_exception()) {
2031 condition = _no_async_condition; // done
2032 switch (thread_state()) {
2033 case _thread_in_vm: {
2034 JavaThread* THREAD = this;
2035 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2036 }
2037 case _thread_in_native: {
2038 ThreadInVMfromNative tiv(this);
2039 JavaThread* THREAD = this;
2040 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2041 }
2042 case _thread_in_Java: {
2043 ThreadInVMfromJava tiv(this);
2044 JavaThread* THREAD = this;
2045 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2046 }
2047 default:
2048 ShouldNotReachHere();
2049 }
2050 }
2051
2052 assert(condition == _no_async_condition || has_pending_exception() ||
2053 (!check_unsafe_error && condition == _async_unsafe_access_error),
2054 "must have handled the async condition, if no exception");
2055 }
2056
2057 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2058 //
2059 // Check for pending external suspend. Internal suspend requests do
2060 // not use handle_special_runtime_exit_condition().
2061 // If JNIEnv proxies are allowed, don't self-suspend if the target
2062 // thread is not the current thread. In older versions of jdbx, jdbx
2063 // threads could call into the VM with another thread's JNIEnv so we
2064 // can be here operating on behalf of a suspended thread (4432884).
2065 bool do_self_suspend = is_external_suspend_with_lock();
2066 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2067 //
2068 // Because thread is external suspended the safepoint code will count
2069 // thread as at a safepoint. This can be odd because we can be here
2070 // as _thread_in_Java which would normally transition to _thread_blocked
2071 // at a safepoint. We would like to mark the thread as _thread_blocked
2072 // before calling java_suspend_self like all other callers of it but
2073 // we must then observe proper safepoint protocol. (We can't leave
2074 // _thread_blocked with a safepoint in progress). However we can be
2075 // here as _thread_in_native_trans so we can't use a normal transition
2076 // constructor/destructor pair because they assert on that type of
2077 // transition. We could do something like:
2078 //
2079 // JavaThreadState state = thread_state();
2080 // set_thread_state(_thread_in_vm);
2081 // {
2082 // ThreadBlockInVM tbivm(this);
2083 // java_suspend_self()
2084 // }
2085 // set_thread_state(_thread_in_vm_trans);
2086 // if (safepoint) block;
2087 // set_thread_state(state);
2088 //
2089 // but that is pretty messy. Instead we just go with the way the
2090 // code has worked before and note that this is the only path to
2091 // java_suspend_self that doesn't put the thread in _thread_blocked
2092 // mode.
2093
2094 frame_anchor()->make_walkable(this);
2095 java_suspend_self();
2096
2097 // We might be here for reasons in addition to the self-suspend request
2098 // so check for other async requests.
2099 }
2100
2101 if (check_asyncs) {
2102 check_and_handle_async_exceptions();
2103 }
2104 }
2105
2106 void JavaThread::send_thread_stop(oop java_throwable) {
2107 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2108 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2109 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2110
2111 // Do not throw asynchronous exceptions against the compiler thread
2112 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2113 if (is_Compiler_thread()) return;
2114
2115 {
2116 // Actually throw the Throwable against the target Thread - however
2117 // only if there is no thread death exception installed already.
2118 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2119 // If the topmost frame is a runtime stub, then we are calling into
2120 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2121 // must deoptimize the caller before continuing, as the compiled exception handler table
2122 // may not be valid
2123 if (has_last_Java_frame()) {
2124 frame f = last_frame();
2125 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2126 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2127 RegisterMap reg_map(this, UseBiasedLocking);
2128 frame compiled_frame = f.sender(®_map);
2129 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2130 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2131 }
2132 }
2133 }
2134
2135 // Set async. pending exception in thread.
2136 set_pending_async_exception(java_throwable);
2137
2138 if (TraceExceptions) {
2139 ResourceMark rm;
2140 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2141 }
2142 // for AbortVMOnException flag
2143 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2144 }
2145 }
2146
2147
2148 // Interrupt thread so it will wake up from a potential wait()
2149 Thread::interrupt(this);
2150 }
2151
2152 // External suspension mechanism.
2153 //
2154 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2155 // to any VM_locks and it is at a transition
2156 // Self-suspension will happen on the transition out of the vm.
2157 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2158 //
2159 // Guarantees on return:
2160 // + Target thread will not execute any new bytecode (that's why we need to
2161 // force a safepoint)
2162 // + Target thread will not enter any new monitors
2163 //
2164 void JavaThread::java_suspend() {
2165 { MutexLocker mu(Threads_lock);
2166 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2167 return;
2168 }
2169 }
2170
2171 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2172 if (!is_external_suspend()) {
2173 // a racing resume has cancelled us; bail out now
2174 return;
2175 }
2176
2177 // suspend is done
2178 uint32_t debug_bits = 0;
2179 // Warning: is_ext_suspend_completed() may temporarily drop the
2180 // SR_lock to allow the thread to reach a stable thread state if
2181 // it is currently in a transient thread state.
2182 if (is_ext_suspend_completed(false /* !called_by_wait */,
2183 SuspendRetryDelay, &debug_bits)) {
2184 return;
2185 }
2186 }
2187
2188 VM_ForceSafepoint vm_suspend;
2189 VMThread::execute(&vm_suspend);
2190 }
2191
2192 // Part II of external suspension.
2193 // A JavaThread self suspends when it detects a pending external suspend
2194 // request. This is usually on transitions. It is also done in places
2195 // where continuing to the next transition would surprise the caller,
2196 // e.g., monitor entry.
2197 //
2198 // Returns the number of times that the thread self-suspended.
2199 //
2200 // Note: DO NOT call java_suspend_self() when you just want to block current
2201 // thread. java_suspend_self() is the second stage of cooperative
2202 // suspension for external suspend requests and should only be used
2203 // to complete an external suspend request.
2204 //
2205 int JavaThread::java_suspend_self() {
2206 int ret = 0;
2207
2208 // we are in the process of exiting so don't suspend
2209 if (is_exiting()) {
2210 clear_external_suspend();
2211 return ret;
2212 }
2213
2214 assert(_anchor.walkable() ||
2215 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2216 "must have walkable stack");
2217
2218 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2219
2220 assert(!this->is_ext_suspended(),
2221 "a thread trying to self-suspend should not already be suspended");
2222
2223 if (this->is_suspend_equivalent()) {
2224 // If we are self-suspending as a result of the lifting of a
2225 // suspend equivalent condition, then the suspend_equivalent
2226 // flag is not cleared until we set the ext_suspended flag so
2227 // that wait_for_ext_suspend_completion() returns consistent
2228 // results.
2229 this->clear_suspend_equivalent();
2230 }
2231
2232 // A racing resume may have cancelled us before we grabbed SR_lock
2233 // above. Or another external suspend request could be waiting for us
2234 // by the time we return from SR_lock()->wait(). The thread
2235 // that requested the suspension may already be trying to walk our
2236 // stack and if we return now, we can change the stack out from under
2237 // it. This would be a "bad thing (TM)" and cause the stack walker
2238 // to crash. We stay self-suspended until there are no more pending
2239 // external suspend requests.
2240 while (is_external_suspend()) {
2241 ret++;
2242 this->set_ext_suspended();
2243
2244 // _ext_suspended flag is cleared by java_resume()
2245 while (is_ext_suspended()) {
2246 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2247 }
2248 }
2249
2250 return ret;
2251 }
2252
2253 #ifdef ASSERT
2254 // verify the JavaThread has not yet been published in the Threads::list, and
2255 // hence doesn't need protection from concurrent access at this stage
2256 void JavaThread::verify_not_published() {
2257 if (!Threads_lock->owned_by_self()) {
2258 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2259 assert(!Threads::includes(this),
2260 "java thread shouldn't have been published yet!");
2261 } else {
2262 assert(!Threads::includes(this),
2263 "java thread shouldn't have been published yet!");
2264 }
2265 }
2266 #endif
2267
2268 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2269 // progress or when _suspend_flags is non-zero.
2270 // Current thread needs to self-suspend if there is a suspend request and/or
2271 // block if a safepoint is in progress.
2272 // Async exception ISN'T checked.
2273 // Note only the ThreadInVMfromNative transition can call this function
2274 // directly and when thread state is _thread_in_native_trans
2275 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2276 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2277
2278 JavaThread *curJT = JavaThread::current();
2279 bool do_self_suspend = thread->is_external_suspend();
2280
2281 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2282
2283 // If JNIEnv proxies are allowed, don't self-suspend if the target
2284 // thread is not the current thread. In older versions of jdbx, jdbx
2285 // threads could call into the VM with another thread's JNIEnv so we
2286 // can be here operating on behalf of a suspended thread (4432884).
2287 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2288 JavaThreadState state = thread->thread_state();
2289
2290 // We mark this thread_blocked state as a suspend-equivalent so
2291 // that a caller to is_ext_suspend_completed() won't be confused.
2292 // The suspend-equivalent state is cleared by java_suspend_self().
2293 thread->set_suspend_equivalent();
2294
2295 // If the safepoint code sees the _thread_in_native_trans state, it will
2296 // wait until the thread changes to other thread state. There is no
2297 // guarantee on how soon we can obtain the SR_lock and complete the
2298 // self-suspend request. It would be a bad idea to let safepoint wait for
2299 // too long. Temporarily change the state to _thread_blocked to
2300 // let the VM thread know that this thread is ready for GC. The problem
2301 // of changing thread state is that safepoint could happen just after
2302 // java_suspend_self() returns after being resumed, and VM thread will
2303 // see the _thread_blocked state. We must check for safepoint
2304 // after restoring the state and make sure we won't leave while a safepoint
2305 // is in progress.
2306 thread->set_thread_state(_thread_blocked);
2307 thread->java_suspend_self();
2308 thread->set_thread_state(state);
2309 // Make sure new state is seen by VM thread
2310 if (os::is_MP()) {
2311 if (UseMembar) {
2312 // Force a fence between the write above and read below
2313 OrderAccess::fence();
2314 } else {
2315 // Must use this rather than serialization page in particular on Windows
2316 InterfaceSupport::serialize_memory(thread);
2317 }
2318 }
2319 }
2320
2321 if (SafepointSynchronize::do_call_back()) {
2322 // If we are safepointing, then block the caller which may not be
2323 // the same as the target thread (see above).
2324 SafepointSynchronize::block(curJT);
2325 }
2326
2327 if (thread->is_deopt_suspend()) {
2328 thread->clear_deopt_suspend();
2329 RegisterMap map(thread, false);
2330 frame f = thread->last_frame();
2331 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2332 f = f.sender(&map);
2333 }
2334 if (f.id() == thread->must_deopt_id()) {
2335 thread->clear_must_deopt_id();
2336 f.deoptimize(thread);
2337 } else {
2338 fatal("missed deoptimization!");
2339 }
2340 }
2341 }
2342
2343 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2344 // progress or when _suspend_flags is non-zero.
2345 // Current thread needs to self-suspend if there is a suspend request and/or
2346 // block if a safepoint is in progress.
2347 // Also check for pending async exception (not including unsafe access error).
2348 // Note only the native==>VM/Java barriers can call this function and when
2349 // thread state is _thread_in_native_trans.
2350 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2351 check_safepoint_and_suspend_for_native_trans(thread);
2352
2353 if (thread->has_async_exception()) {
2354 // We are in _thread_in_native_trans state, don't handle unsafe
2355 // access error since that may block.
2356 thread->check_and_handle_async_exceptions(false);
2357 }
2358 }
2359
2360 // This is a variant of the normal
2361 // check_special_condition_for_native_trans with slightly different
2362 // semantics for use by critical native wrappers. It does all the
2363 // normal checks but also performs the transition back into
2364 // thread_in_Java state. This is required so that critical natives
2365 // can potentially block and perform a GC if they are the last thread
2366 // exiting the GC_locker.
2367 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2368 check_special_condition_for_native_trans(thread);
2369
2370 // Finish the transition
2371 thread->set_thread_state(_thread_in_Java);
2372
2373 if (thread->do_critical_native_unlock()) {
2374 ThreadInVMfromJavaNoAsyncException tiv(thread);
2375 GC_locker::unlock_critical(thread);
2376 thread->clear_critical_native_unlock();
2377 }
2378 }
2379
2380 // We need to guarantee the Threads_lock here, since resumes are not
2381 // allowed during safepoint synchronization
2382 // Can only resume from an external suspension
2383 void JavaThread::java_resume() {
2384 assert_locked_or_safepoint(Threads_lock);
2385
2386 // Sanity check: thread is gone, has started exiting or the thread
2387 // was not externally suspended.
2388 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2389 return;
2390 }
2391
2392 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2393
2394 clear_external_suspend();
2395
2396 if (is_ext_suspended()) {
2397 clear_ext_suspended();
2398 SR_lock()->notify_all();
2399 }
2400 }
2401
2402 void JavaThread::create_stack_guard_pages() {
2403 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2404 address low_addr = stack_base() - stack_size();
2405 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2406
2407 int allocate = os::allocate_stack_guard_pages();
2408 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2409
2410 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2411 warning("Attempt to allocate stack guard pages failed.");
2412 return;
2413 }
2414
2415 if (os::guard_memory((char *) low_addr, len)) {
2416 _stack_guard_state = stack_guard_enabled;
2417 } else {
2418 warning("Attempt to protect stack guard pages failed.");
2419 if (os::uncommit_memory((char *) low_addr, len)) {
2420 warning("Attempt to deallocate stack guard pages failed.");
2421 }
2422 }
2423 }
2424
2425 void JavaThread::remove_stack_guard_pages() {
2426 assert(Thread::current() == this, "from different thread");
2427 if (_stack_guard_state == stack_guard_unused) return;
2428 address low_addr = stack_base() - stack_size();
2429 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2430
2431 if (os::allocate_stack_guard_pages()) {
2432 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2433 _stack_guard_state = stack_guard_unused;
2434 } else {
2435 warning("Attempt to deallocate stack guard pages failed.");
2436 }
2437 } else {
2438 if (_stack_guard_state == stack_guard_unused) return;
2439 if (os::unguard_memory((char *) low_addr, len)) {
2440 _stack_guard_state = stack_guard_unused;
2441 } else {
2442 warning("Attempt to unprotect stack guard pages failed.");
2443 }
2444 }
2445 }
2446
2447 void JavaThread::enable_stack_yellow_zone() {
2448 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2449 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2450
2451 // The base notation is from the stacks point of view, growing downward.
2452 // We need to adjust it to work correctly with guard_memory()
2453 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2454
2455 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2456 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2457
2458 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2459 _stack_guard_state = stack_guard_enabled;
2460 } else {
2461 warning("Attempt to guard stack yellow zone failed.");
2462 }
2463 enable_register_stack_guard();
2464 }
2465
2466 void JavaThread::disable_stack_yellow_zone() {
2467 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2468 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2469
2470 // Simply return if called for a thread that does not use guard pages.
2471 if (_stack_guard_state == stack_guard_unused) return;
2472
2473 // The base notation is from the stacks point of view, growing downward.
2474 // We need to adjust it to work correctly with guard_memory()
2475 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2476
2477 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2478 _stack_guard_state = stack_guard_yellow_disabled;
2479 } else {
2480 warning("Attempt to unguard stack yellow zone failed.");
2481 }
2482 disable_register_stack_guard();
2483 }
2484
2485 void JavaThread::enable_stack_red_zone() {
2486 // The base notation is from the stacks point of view, growing downward.
2487 // We need to adjust it to work correctly with guard_memory()
2488 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2489 address base = stack_red_zone_base() - stack_red_zone_size();
2490
2491 guarantee(base < stack_base(), "Error calculating stack red zone");
2492 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2493
2494 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2495 warning("Attempt to guard stack red zone failed.");
2496 }
2497 }
2498
2499 void JavaThread::disable_stack_red_zone() {
2500 // The base notation is from the stacks point of view, growing downward.
2501 // We need to adjust it to work correctly with guard_memory()
2502 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2503 address base = stack_red_zone_base() - stack_red_zone_size();
2504 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2505 warning("Attempt to unguard stack red zone failed.");
2506 }
2507 }
2508
2509 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2510 // ignore is there is no stack
2511 if (!has_last_Java_frame()) return;
2512 // traverse the stack frames. Starts from top frame.
2513 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2514 frame* fr = fst.current();
2515 f(fr, fst.register_map());
2516 }
2517 }
2518
2519
2520 #ifndef PRODUCT
2521 // Deoptimization
2522 // Function for testing deoptimization
2523 void JavaThread::deoptimize() {
2524 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2525 StackFrameStream fst(this, UseBiasedLocking);
2526 bool deopt = false; // Dump stack only if a deopt actually happens.
2527 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2528 // Iterate over all frames in the thread and deoptimize
2529 for (; !fst.is_done(); fst.next()) {
2530 if (fst.current()->can_be_deoptimized()) {
2531
2532 if (only_at) {
2533 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2534 // consists of comma or carriage return separated numbers so
2535 // search for the current bci in that string.
2536 address pc = fst.current()->pc();
2537 nmethod* nm = (nmethod*) fst.current()->cb();
2538 ScopeDesc* sd = nm->scope_desc_at(pc);
2539 char buffer[8];
2540 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2541 size_t len = strlen(buffer);
2542 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2543 while (found != NULL) {
2544 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2545 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2546 // Check that the bci found is bracketed by terminators.
2547 break;
2548 }
2549 found = strstr(found + 1, buffer);
2550 }
2551 if (!found) {
2552 continue;
2553 }
2554 }
2555
2556 if (DebugDeoptimization && !deopt) {
2557 deopt = true; // One-time only print before deopt
2558 tty->print_cr("[BEFORE Deoptimization]");
2559 trace_frames();
2560 trace_stack();
2561 }
2562 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2563 }
2564 }
2565
2566 if (DebugDeoptimization && deopt) {
2567 tty->print_cr("[AFTER Deoptimization]");
2568 trace_frames();
2569 }
2570 }
2571
2572
2573 // Make zombies
2574 void JavaThread::make_zombies() {
2575 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2576 if (fst.current()->can_be_deoptimized()) {
2577 // it is a Java nmethod
2578 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2579 nm->make_not_entrant();
2580 }
2581 }
2582 }
2583 #endif // PRODUCT
2584
2585
2586 void JavaThread::deoptimized_wrt_marked_nmethods() {
2587 if (!has_last_Java_frame()) return;
2588 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2589 StackFrameStream fst(this, UseBiasedLocking);
2590 for (; !fst.is_done(); fst.next()) {
2591 if (fst.current()->should_be_deoptimized()) {
2592 if (LogCompilation && xtty != NULL) {
2593 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2594 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2595 this->name(), nm != NULL ? nm->compile_id() : -1);
2596 }
2597
2598 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2599 }
2600 }
2601 }
2602
2603
2604 // If the caller is a NamedThread, then remember, in the current scope,
2605 // the given JavaThread in its _processed_thread field.
2606 class RememberProcessedThread: public StackObj {
2607 NamedThread* _cur_thr;
2608 public:
2609 RememberProcessedThread(JavaThread* jthr) {
2610 Thread* thread = Thread::current();
2611 if (thread->is_Named_thread()) {
2612 _cur_thr = (NamedThread *)thread;
2613 _cur_thr->set_processed_thread(jthr);
2614 } else {
2615 _cur_thr = NULL;
2616 }
2617 }
2618
2619 ~RememberProcessedThread() {
2620 if (_cur_thr) {
2621 _cur_thr->set_processed_thread(NULL);
2622 }
2623 }
2624 };
2625
2626 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2627 // Verify that the deferred card marks have been flushed.
2628 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2629
2630 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2631 // since there may be more than one thread using each ThreadProfiler.
2632
2633 // Traverse the GCHandles
2634 Thread::oops_do(f, cld_f, cf);
2635
2636 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2637 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2638
2639 if (has_last_Java_frame()) {
2640 // Record JavaThread to GC thread
2641 RememberProcessedThread rpt(this);
2642
2643 // Traverse the privileged stack
2644 if (_privileged_stack_top != NULL) {
2645 _privileged_stack_top->oops_do(f);
2646 }
2647
2648 // traverse the registered growable array
2649 if (_array_for_gc != NULL) {
2650 for (int index = 0; index < _array_for_gc->length(); index++) {
2651 f->do_oop(_array_for_gc->adr_at(index));
2652 }
2653 }
2654
2655 // Traverse the monitor chunks
2656 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2657 chunk->oops_do(f);
2658 }
2659
2660 // Traverse the execution stack
2661 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2662 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2663 }
2664 }
2665
2666 // callee_target is never live across a gc point so NULL it here should
2667 // it still contain a methdOop.
2668
2669 set_callee_target(NULL);
2670
2671 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2672 // If we have deferred set_locals there might be oops waiting to be
2673 // written
2674 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2675 if (list != NULL) {
2676 for (int i = 0; i < list->length(); i++) {
2677 list->at(i)->oops_do(f);
2678 }
2679 }
2680
2681 // Traverse instance variables at the end since the GC may be moving things
2682 // around using this function
2683 f->do_oop((oop*) &_threadObj);
2684 f->do_oop((oop*) &_vm_result);
2685 f->do_oop((oop*) &_exception_oop);
2686 f->do_oop((oop*) &_pending_async_exception);
2687
2688 if (jvmti_thread_state() != NULL) {
2689 jvmti_thread_state()->oops_do(f);
2690 }
2691 }
2692
2693 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2694 Thread::nmethods_do(cf); // (super method is a no-op)
2695
2696 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2697 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2698
2699 if (has_last_Java_frame()) {
2700 // Traverse the execution stack
2701 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2702 fst.current()->nmethods_do(cf);
2703 }
2704 }
2705 }
2706
2707 void JavaThread::metadata_do(void f(Metadata*)) {
2708 Thread::metadata_do(f);
2709 if (has_last_Java_frame()) {
2710 // Traverse the execution stack to call f() on the methods in the stack
2711 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2712 fst.current()->metadata_do(f);
2713 }
2714 } else if (is_Compiler_thread()) {
2715 // need to walk ciMetadata in current compile tasks to keep alive.
2716 CompilerThread* ct = (CompilerThread*)this;
2717 if (ct->env() != NULL) {
2718 ct->env()->metadata_do(f);
2719 }
2720 }
2721 }
2722
2723 // Printing
2724 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2725 switch (_thread_state) {
2726 case _thread_uninitialized: return "_thread_uninitialized";
2727 case _thread_new: return "_thread_new";
2728 case _thread_new_trans: return "_thread_new_trans";
2729 case _thread_in_native: return "_thread_in_native";
2730 case _thread_in_native_trans: return "_thread_in_native_trans";
2731 case _thread_in_vm: return "_thread_in_vm";
2732 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2733 case _thread_in_Java: return "_thread_in_Java";
2734 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2735 case _thread_blocked: return "_thread_blocked";
2736 case _thread_blocked_trans: return "_thread_blocked_trans";
2737 default: return "unknown thread state";
2738 }
2739 }
2740
2741 #ifndef PRODUCT
2742 void JavaThread::print_thread_state_on(outputStream *st) const {
2743 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2744 };
2745 void JavaThread::print_thread_state() const {
2746 print_thread_state_on(tty);
2747 }
2748 #endif // PRODUCT
2749
2750 // Called by Threads::print() for VM_PrintThreads operation
2751 void JavaThread::print_on(outputStream *st) const {
2752 st->print("\"%s\" ", get_thread_name());
2753 oop thread_oop = threadObj();
2754 if (thread_oop != NULL) {
2755 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2756 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2757 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2758 }
2759 Thread::print_on(st);
2760 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2761 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2762 if (thread_oop != NULL) {
2763 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2764 }
2765 #ifndef PRODUCT
2766 print_thread_state_on(st);
2767 _safepoint_state->print_on(st);
2768 #endif // PRODUCT
2769 }
2770
2771 // Called by fatal error handler. The difference between this and
2772 // JavaThread::print() is that we can't grab lock or allocate memory.
2773 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2774 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2775 oop thread_obj = threadObj();
2776 if (thread_obj != NULL) {
2777 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2778 }
2779 st->print(" [");
2780 st->print("%s", _get_thread_state_name(_thread_state));
2781 if (osthread()) {
2782 st->print(", id=%d", osthread()->thread_id());
2783 }
2784 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2785 _stack_base - _stack_size, _stack_base);
2786 st->print("]");
2787 return;
2788 }
2789
2790 // Verification
2791
2792 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2793
2794 void JavaThread::verify() {
2795 // Verify oops in the thread.
2796 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2797
2798 // Verify the stack frames.
2799 frames_do(frame_verify);
2800 }
2801
2802 // CR 6300358 (sub-CR 2137150)
2803 // Most callers of this method assume that it can't return NULL but a
2804 // thread may not have a name whilst it is in the process of attaching to
2805 // the VM - see CR 6412693, and there are places where a JavaThread can be
2806 // seen prior to having it's threadObj set (eg JNI attaching threads and
2807 // if vm exit occurs during initialization). These cases can all be accounted
2808 // for such that this method never returns NULL.
2809 const char* JavaThread::get_thread_name() const {
2810 #ifdef ASSERT
2811 // early safepoints can hit while current thread does not yet have TLS
2812 if (!SafepointSynchronize::is_at_safepoint()) {
2813 Thread *cur = Thread::current();
2814 if (!(cur->is_Java_thread() && cur == this)) {
2815 // Current JavaThreads are allowed to get their own name without
2816 // the Threads_lock.
2817 assert_locked_or_safepoint(Threads_lock);
2818 }
2819 }
2820 #endif // ASSERT
2821 return get_thread_name_string();
2822 }
2823
2824 // Returns a non-NULL representation of this thread's name, or a suitable
2825 // descriptive string if there is no set name
2826 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2827 const char* name_str;
2828 oop thread_obj = threadObj();
2829 if (thread_obj != NULL) {
2830 oop name = java_lang_Thread::name(thread_obj);
2831 if (name != NULL) {
2832 if (buf == NULL) {
2833 name_str = java_lang_String::as_utf8_string(name);
2834 } else {
2835 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2836 }
2837 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2838 name_str = "<no-name - thread is attaching>";
2839 } else {
2840 name_str = Thread::name();
2841 }
2842 } else {
2843 name_str = Thread::name();
2844 }
2845 assert(name_str != NULL, "unexpected NULL thread name");
2846 return name_str;
2847 }
2848
2849
2850 const char* JavaThread::get_threadgroup_name() const {
2851 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2852 oop thread_obj = threadObj();
2853 if (thread_obj != NULL) {
2854 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2855 if (thread_group != NULL) {
2856 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2857 // ThreadGroup.name can be null
2858 if (name != NULL) {
2859 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2860 return str;
2861 }
2862 }
2863 }
2864 return NULL;
2865 }
2866
2867 const char* JavaThread::get_parent_name() const {
2868 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2869 oop thread_obj = threadObj();
2870 if (thread_obj != NULL) {
2871 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2872 if (thread_group != NULL) {
2873 oop parent = java_lang_ThreadGroup::parent(thread_group);
2874 if (parent != NULL) {
2875 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2876 // ThreadGroup.name can be null
2877 if (name != NULL) {
2878 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2879 return str;
2880 }
2881 }
2882 }
2883 }
2884 return NULL;
2885 }
2886
2887 ThreadPriority JavaThread::java_priority() const {
2888 oop thr_oop = threadObj();
2889 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2890 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2891 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2892 return priority;
2893 }
2894
2895 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2896
2897 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2898 // Link Java Thread object <-> C++ Thread
2899
2900 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2901 // and put it into a new Handle. The Handle "thread_oop" can then
2902 // be used to pass the C++ thread object to other methods.
2903
2904 // Set the Java level thread object (jthread) field of the
2905 // new thread (a JavaThread *) to C++ thread object using the
2906 // "thread_oop" handle.
2907
2908 // Set the thread field (a JavaThread *) of the
2909 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2910
2911 Handle thread_oop(Thread::current(),
2912 JNIHandles::resolve_non_null(jni_thread));
2913 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2914 "must be initialized");
2915 set_threadObj(thread_oop());
2916 java_lang_Thread::set_thread(thread_oop(), this);
2917
2918 if (prio == NoPriority) {
2919 prio = java_lang_Thread::priority(thread_oop());
2920 assert(prio != NoPriority, "A valid priority should be present");
2921 }
2922
2923 // Push the Java priority down to the native thread; needs Threads_lock
2924 Thread::set_priority(this, prio);
2925
2926 prepare_ext();
2927
2928 // Add the new thread to the Threads list and set it in motion.
2929 // We must have threads lock in order to call Threads::add.
2930 // It is crucial that we do not block before the thread is
2931 // added to the Threads list for if a GC happens, then the java_thread oop
2932 // will not be visited by GC.
2933 Threads::add(this);
2934 }
2935
2936 oop JavaThread::current_park_blocker() {
2937 // Support for JSR-166 locks
2938 oop thread_oop = threadObj();
2939 if (thread_oop != NULL &&
2940 JDK_Version::current().supports_thread_park_blocker()) {
2941 return java_lang_Thread::park_blocker(thread_oop);
2942 }
2943 return NULL;
2944 }
2945
2946
2947 void JavaThread::print_stack_on(outputStream* st) {
2948 if (!has_last_Java_frame()) return;
2949 ResourceMark rm;
2950 HandleMark hm;
2951
2952 RegisterMap reg_map(this);
2953 vframe* start_vf = last_java_vframe(®_map);
2954 int count = 0;
2955 for (vframe* f = start_vf; f; f = f->sender()) {
2956 if (f->is_java_frame()) {
2957 javaVFrame* jvf = javaVFrame::cast(f);
2958 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2959
2960 // Print out lock information
2961 if (JavaMonitorsInStackTrace) {
2962 jvf->print_lock_info_on(st, count);
2963 }
2964 } else {
2965 // Ignore non-Java frames
2966 }
2967
2968 // Bail-out case for too deep stacks
2969 count++;
2970 if (MaxJavaStackTraceDepth == count) return;
2971 }
2972 }
2973
2974
2975 // JVMTI PopFrame support
2976 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2977 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2978 if (in_bytes(size_in_bytes) != 0) {
2979 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
2980 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2981 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2982 }
2983 }
2984
2985 void* JavaThread::popframe_preserved_args() {
2986 return _popframe_preserved_args;
2987 }
2988
2989 ByteSize JavaThread::popframe_preserved_args_size() {
2990 return in_ByteSize(_popframe_preserved_args_size);
2991 }
2992
2993 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2994 int sz = in_bytes(popframe_preserved_args_size());
2995 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2996 return in_WordSize(sz / wordSize);
2997 }
2998
2999 void JavaThread::popframe_free_preserved_args() {
3000 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3001 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3002 _popframe_preserved_args = NULL;
3003 _popframe_preserved_args_size = 0;
3004 }
3005
3006 #ifndef PRODUCT
3007
3008 void JavaThread::trace_frames() {
3009 tty->print_cr("[Describe stack]");
3010 int frame_no = 1;
3011 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3012 tty->print(" %d. ", frame_no++);
3013 fst.current()->print_value_on(tty, this);
3014 tty->cr();
3015 }
3016 }
3017
3018 class PrintAndVerifyOopClosure: public OopClosure {
3019 protected:
3020 template <class T> inline void do_oop_work(T* p) {
3021 oop obj = oopDesc::load_decode_heap_oop(p);
3022 if (obj == NULL) return;
3023 tty->print(INTPTR_FORMAT ": ", p);
3024 if (obj->is_oop_or_null()) {
3025 if (obj->is_objArray()) {
3026 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3027 } else {
3028 obj->print();
3029 }
3030 } else {
3031 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3032 }
3033 tty->cr();
3034 }
3035 public:
3036 virtual void do_oop(oop* p) { do_oop_work(p); }
3037 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3038 };
3039
3040
3041 static void oops_print(frame* f, const RegisterMap *map) {
3042 PrintAndVerifyOopClosure print;
3043 f->print_value();
3044 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3045 }
3046
3047 // Print our all the locations that contain oops and whether they are
3048 // valid or not. This useful when trying to find the oldest frame
3049 // where an oop has gone bad since the frame walk is from youngest to
3050 // oldest.
3051 void JavaThread::trace_oops() {
3052 tty->print_cr("[Trace oops]");
3053 frames_do(oops_print);
3054 }
3055
3056
3057 #ifdef ASSERT
3058 // Print or validate the layout of stack frames
3059 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3060 ResourceMark rm;
3061 PRESERVE_EXCEPTION_MARK;
3062 FrameValues values;
3063 int frame_no = 0;
3064 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3065 fst.current()->describe(values, ++frame_no);
3066 if (depth == frame_no) break;
3067 }
3068 if (validate_only) {
3069 values.validate();
3070 } else {
3071 tty->print_cr("[Describe stack layout]");
3072 values.print(this);
3073 }
3074 }
3075 #endif
3076
3077 void JavaThread::trace_stack_from(vframe* start_vf) {
3078 ResourceMark rm;
3079 int vframe_no = 1;
3080 for (vframe* f = start_vf; f; f = f->sender()) {
3081 if (f->is_java_frame()) {
3082 javaVFrame::cast(f)->print_activation(vframe_no++);
3083 } else {
3084 f->print();
3085 }
3086 if (vframe_no > StackPrintLimit) {
3087 tty->print_cr("...<more frames>...");
3088 return;
3089 }
3090 }
3091 }
3092
3093
3094 void JavaThread::trace_stack() {
3095 if (!has_last_Java_frame()) return;
3096 ResourceMark rm;
3097 HandleMark hm;
3098 RegisterMap reg_map(this);
3099 trace_stack_from(last_java_vframe(®_map));
3100 }
3101
3102
3103 #endif // PRODUCT
3104
3105
3106 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3107 assert(reg_map != NULL, "a map must be given");
3108 frame f = last_frame();
3109 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3110 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3111 }
3112 return NULL;
3113 }
3114
3115
3116 Klass* JavaThread::security_get_caller_class(int depth) {
3117 vframeStream vfst(this);
3118 vfst.security_get_caller_frame(depth);
3119 if (!vfst.at_end()) {
3120 return vfst.method()->method_holder();
3121 }
3122 return NULL;
3123 }
3124
3125 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3126 assert(thread->is_Compiler_thread(), "must be compiler thread");
3127 CompileBroker::compiler_thread_loop();
3128 }
3129
3130 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3131 NMethodSweeper::sweeper_loop();
3132 }
3133
3134 // Create a CompilerThread
3135 CompilerThread::CompilerThread(CompileQueue* queue,
3136 CompilerCounters* counters)
3137 : JavaThread(&compiler_thread_entry) {
3138 _env = NULL;
3139 _log = NULL;
3140 _task = NULL;
3141 _queue = queue;
3142 _counters = counters;
3143 _buffer_blob = NULL;
3144 _compiler = NULL;
3145
3146 #ifndef PRODUCT
3147 _ideal_graph_printer = NULL;
3148 #endif
3149 }
3150
3151 // Create sweeper thread
3152 CodeCacheSweeperThread::CodeCacheSweeperThread()
3153 : JavaThread(&sweeper_thread_entry) {
3154 _scanned_nmethod = NULL;
3155 }
3156 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3157 JavaThread::oops_do(f, cld_f, cf);
3158 if (_scanned_nmethod != NULL && cf != NULL) {
3159 // Safepoints can occur when the sweeper is scanning an nmethod so
3160 // process it here to make sure it isn't unloaded in the middle of
3161 // a scan.
3162 cf->do_code_blob(_scanned_nmethod);
3163 }
3164 }
3165
3166
3167 // ======= Threads ========
3168
3169 // The Threads class links together all active threads, and provides
3170 // operations over all threads. It is protected by its own Mutex
3171 // lock, which is also used in other contexts to protect thread
3172 // operations from having the thread being operated on from exiting
3173 // and going away unexpectedly (e.g., safepoint synchronization)
3174
3175 JavaThread* Threads::_thread_list = NULL;
3176 int Threads::_number_of_threads = 0;
3177 int Threads::_number_of_non_daemon_threads = 0;
3178 int Threads::_return_code = 0;
3179 size_t JavaThread::_stack_size_at_create = 0;
3180 #ifdef ASSERT
3181 bool Threads::_vm_complete = false;
3182 #endif
3183
3184 // All JavaThreads
3185 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3186
3187 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3188 void Threads::threads_do(ThreadClosure* tc) {
3189 assert_locked_or_safepoint(Threads_lock);
3190 // ALL_JAVA_THREADS iterates through all JavaThreads
3191 ALL_JAVA_THREADS(p) {
3192 tc->do_thread(p);
3193 }
3194 // Someday we could have a table or list of all non-JavaThreads.
3195 // For now, just manually iterate through them.
3196 tc->do_thread(VMThread::vm_thread());
3197 Universe::heap()->gc_threads_do(tc);
3198 WatcherThread *wt = WatcherThread::watcher_thread();
3199 // Strictly speaking, the following NULL check isn't sufficient to make sure
3200 // the data for WatcherThread is still valid upon being examined. However,
3201 // considering that WatchThread terminates when the VM is on the way to
3202 // exit at safepoint, the chance of the above is extremely small. The right
3203 // way to prevent termination of WatcherThread would be to acquire
3204 // Terminator_lock, but we can't do that without violating the lock rank
3205 // checking in some cases.
3206 if (wt != NULL) {
3207 tc->do_thread(wt);
3208 }
3209
3210 // If CompilerThreads ever become non-JavaThreads, add them here
3211 }
3212
3213
3214 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3215 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3216
3217 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3218 create_vm_init_libraries();
3219 }
3220
3221 initialize_class(vmSymbols::java_lang_String(), CHECK);
3222
3223 // Initialize java_lang.System (needed before creating the thread)
3224 initialize_class(vmSymbols::java_lang_System(), CHECK);
3225 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3226 Handle thread_group = create_initial_thread_group(CHECK);
3227 Universe::set_main_thread_group(thread_group());
3228 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3229 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3230 main_thread->set_threadObj(thread_object);
3231 // Set thread status to running since main thread has
3232 // been started and running.
3233 java_lang_Thread::set_thread_status(thread_object,
3234 java_lang_Thread::RUNNABLE);
3235
3236 // The VM creates & returns objects of this class. Make sure it's initialized.
3237 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3238
3239 // The VM preresolves methods to these classes. Make sure that they get initialized
3240 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3241 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3242 call_initializeSystemClass(CHECK);
3243
3244 // get the Java runtime name after java.lang.System is initialized
3245 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3246 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3247
3248 // an instance of OutOfMemory exception has been allocated earlier
3249 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3250 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3251 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3252 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3253 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3254 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3255 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3256 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3257 }
3258
3259 void Threads::initialize_jsr292_core_classes(TRAPS) {
3260 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3261 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3262 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3263 }
3264
3265 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3266 extern void JDK_Version_init();
3267
3268 // Check version
3269 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3270
3271 // Initialize the output stream module
3272 ostream_init();
3273
3274 // Process java launcher properties.
3275 Arguments::process_sun_java_launcher_properties(args);
3276
3277 // Initialize the os module before using TLS
3278 os::init();
3279
3280 // Initialize system properties.
3281 Arguments::init_system_properties();
3282
3283 // So that JDK version can be used as a discriminator when parsing arguments
3284 JDK_Version_init();
3285
3286 // Update/Initialize System properties after JDK version number is known
3287 Arguments::init_version_specific_system_properties();
3288
3289 // Parse arguments
3290 jint parse_result = Arguments::parse(args);
3291 if (parse_result != JNI_OK) return parse_result;
3292
3293 os::init_before_ergo();
3294
3295 jint ergo_result = Arguments::apply_ergo();
3296 if (ergo_result != JNI_OK) return ergo_result;
3297
3298 if (PauseAtStartup) {
3299 os::pause();
3300 }
3301
3302 HOTSPOT_VM_INIT_BEGIN();
3303
3304 // Record VM creation timing statistics
3305 TraceVmCreationTime create_vm_timer;
3306 create_vm_timer.start();
3307
3308 // Timing (must come after argument parsing)
3309 TraceTime timer("Create VM", TraceStartupTime);
3310
3311 // Initialize the os module after parsing the args
3312 jint os_init_2_result = os::init_2();
3313 if (os_init_2_result != JNI_OK) return os_init_2_result;
3314
3315 jint adjust_after_os_result = Arguments::adjust_after_os();
3316 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3317
3318 // initialize TLS
3319 ThreadLocalStorage::init();
3320
3321 // Initialize output stream logging
3322 ostream_init_log();
3323
3324 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3325 // Must be before create_vm_init_agents()
3326 if (Arguments::init_libraries_at_startup()) {
3327 convert_vm_init_libraries_to_agents();
3328 }
3329
3330 // Launch -agentlib/-agentpath and converted -Xrun agents
3331 if (Arguments::init_agents_at_startup()) {
3332 create_vm_init_agents();
3333 }
3334
3335 // Initialize Threads state
3336 _thread_list = NULL;
3337 _number_of_threads = 0;
3338 _number_of_non_daemon_threads = 0;
3339
3340 // Initialize global data structures and create system classes in heap
3341 vm_init_globals();
3342
3343 // Attach the main thread to this os thread
3344 JavaThread* main_thread = new JavaThread();
3345 main_thread->set_thread_state(_thread_in_vm);
3346 // must do this before set_active_handles and initialize_thread_local_storage
3347 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3348 // change the stack size recorded here to one based on the java thread
3349 // stacksize. This adjusted size is what is used to figure the placement
3350 // of the guard pages.
3351 main_thread->record_stack_base_and_size();
3352 main_thread->initialize_thread_local_storage();
3353
3354 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3355
3356 if (!main_thread->set_as_starting_thread()) {
3357 vm_shutdown_during_initialization(
3358 "Failed necessary internal allocation. Out of swap space");
3359 delete main_thread;
3360 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3361 return JNI_ENOMEM;
3362 }
3363
3364 // Enable guard page *after* os::create_main_thread(), otherwise it would
3365 // crash Linux VM, see notes in os_linux.cpp.
3366 main_thread->create_stack_guard_pages();
3367
3368 // Initialize Java-Level synchronization subsystem
3369 ObjectMonitor::Initialize();
3370
3371 // Initialize global modules
3372 jint status = init_globals();
3373 if (status != JNI_OK) {
3374 delete main_thread;
3375 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3376 return status;
3377 }
3378
3379 // Should be done after the heap is fully created
3380 main_thread->cache_global_variables();
3381
3382 HandleMark hm;
3383
3384 { MutexLocker mu(Threads_lock);
3385 Threads::add(main_thread);
3386 }
3387
3388 // Any JVMTI raw monitors entered in onload will transition into
3389 // real raw monitor. VM is setup enough here for raw monitor enter.
3390 JvmtiExport::transition_pending_onload_raw_monitors();
3391
3392 // Create the VMThread
3393 { TraceTime timer("Start VMThread", TraceStartupTime);
3394 VMThread::create();
3395 Thread* vmthread = VMThread::vm_thread();
3396
3397 if (!os::create_thread(vmthread, os::vm_thread)) {
3398 vm_exit_during_initialization("Cannot create VM thread. "
3399 "Out of system resources.");
3400 }
3401
3402 // Wait for the VM thread to become ready, and VMThread::run to initialize
3403 // Monitors can have spurious returns, must always check another state flag
3404 {
3405 MutexLocker ml(Notify_lock);
3406 os::start_thread(vmthread);
3407 while (vmthread->active_handles() == NULL) {
3408 Notify_lock->wait();
3409 }
3410 }
3411 }
3412
3413 assert(Universe::is_fully_initialized(), "not initialized");
3414 if (VerifyDuringStartup) {
3415 // Make sure we're starting with a clean slate.
3416 VM_Verify verify_op;
3417 VMThread::execute(&verify_op);
3418 }
3419
3420 Thread* THREAD = Thread::current();
3421
3422 // At this point, the Universe is initialized, but we have not executed
3423 // any byte code. Now is a good time (the only time) to dump out the
3424 // internal state of the JVM for sharing.
3425 if (DumpSharedSpaces) {
3426 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3427 ShouldNotReachHere();
3428 }
3429
3430 // Always call even when there are not JVMTI environments yet, since environments
3431 // may be attached late and JVMTI must track phases of VM execution
3432 JvmtiExport::enter_start_phase();
3433
3434 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3435 JvmtiExport::post_vm_start();
3436
3437 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3438
3439 // We need this for ClassDataSharing - the initial vm.info property is set
3440 // with the default value of CDS "sharing" which may be reset through
3441 // command line options.
3442 reset_vm_info_property(CHECK_JNI_ERR);
3443
3444 quicken_jni_functions();
3445
3446 // Must be run after init_ft which initializes ft_enabled
3447 if (TRACE_INITIALIZE() != JNI_OK) {
3448 vm_exit_during_initialization("Failed to initialize tracing backend");
3449 }
3450
3451 // Set flag that basic initialization has completed. Used by exceptions and various
3452 // debug stuff, that does not work until all basic classes have been initialized.
3453 set_init_completed();
3454
3455 Metaspace::post_initialize();
3456
3457 HOTSPOT_VM_INIT_END();
3458
3459 // record VM initialization completion time
3460 #if INCLUDE_MANAGEMENT
3461 Management::record_vm_init_completed();
3462 #endif // INCLUDE_MANAGEMENT
3463
3464 // Compute system loader. Note that this has to occur after set_init_completed, since
3465 // valid exceptions may be thrown in the process.
3466 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3467 // set_init_completed has just been called, causing exceptions not to be shortcut
3468 // anymore. We call vm_exit_during_initialization directly instead.
3469 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3470
3471 #if INCLUDE_ALL_GCS
3472 // Support for ConcurrentMarkSweep. This should be cleaned up
3473 // and better encapsulated. The ugly nested if test would go away
3474 // once things are properly refactored. XXX YSR
3475 if (UseConcMarkSweepGC || UseG1GC) {
3476 if (UseConcMarkSweepGC) {
3477 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3478 } else {
3479 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3480 }
3481 }
3482 #endif // INCLUDE_ALL_GCS
3483
3484 // Always call even when there are not JVMTI environments yet, since environments
3485 // may be attached late and JVMTI must track phases of VM execution
3486 JvmtiExport::enter_live_phase();
3487
3488 // Signal Dispatcher needs to be started before VMInit event is posted
3489 os::signal_init();
3490
3491 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3492 if (!DisableAttachMechanism) {
3493 AttachListener::vm_start();
3494 if (StartAttachListener || AttachListener::init_at_startup()) {
3495 AttachListener::init();
3496 }
3497 }
3498
3499 // Launch -Xrun agents
3500 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3501 // back-end can launch with -Xdebug -Xrunjdwp.
3502 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3503 create_vm_init_libraries();
3504 }
3505
3506 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3507 JvmtiExport::post_vm_initialized();
3508
3509 if (TRACE_START() != JNI_OK) {
3510 vm_exit_during_initialization("Failed to start tracing backend.");
3511 }
3512
3513 if (CleanChunkPoolAsync) {
3514 Chunk::start_chunk_pool_cleaner_task();
3515 }
3516
3517 // initialize compiler(s)
3518 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3519 CompileBroker::compilation_init();
3520 #endif
3521
3522 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3523 // It is done after compilers are initialized, because otherwise compilations of
3524 // signature polymorphic MH intrinsics can be missed
3525 // (see SystemDictionary::find_method_handle_intrinsic).
3526 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3527
3528 #if INCLUDE_MANAGEMENT
3529 Management::initialize(THREAD);
3530
3531 if (HAS_PENDING_EXCEPTION) {
3532 // management agent fails to start possibly due to
3533 // configuration problem and is responsible for printing
3534 // stack trace if appropriate. Simply exit VM.
3535 vm_exit(1);
3536 }
3537 #endif // INCLUDE_MANAGEMENT
3538
3539 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3540 if (MemProfiling) MemProfiler::engage();
3541 StatSampler::engage();
3542 if (CheckJNICalls) JniPeriodicChecker::engage();
3543
3544 BiasedLocking::init();
3545
3546 #if INCLUDE_RTM_OPT
3547 RTMLockingCounters::init();
3548 #endif
3549
3550 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3551 call_postVMInitHook(THREAD);
3552 // The Java side of PostVMInitHook.run must deal with all
3553 // exceptions and provide means of diagnosis.
3554 if (HAS_PENDING_EXCEPTION) {
3555 CLEAR_PENDING_EXCEPTION;
3556 }
3557 }
3558
3559 {
3560 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3561 // Make sure the watcher thread can be started by WatcherThread::start()
3562 // or by dynamic enrollment.
3563 WatcherThread::make_startable();
3564 // Start up the WatcherThread if there are any periodic tasks
3565 // NOTE: All PeriodicTasks should be registered by now. If they
3566 // aren't, late joiners might appear to start slowly (we might
3567 // take a while to process their first tick).
3568 if (PeriodicTask::num_tasks() > 0) {
3569 WatcherThread::start();
3570 }
3571 }
3572
3573 create_vm_timer.end();
3574 #ifdef ASSERT
3575 _vm_complete = true;
3576 #endif
3577 return JNI_OK;
3578 }
3579
3580 // type for the Agent_OnLoad and JVM_OnLoad entry points
3581 extern "C" {
3582 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3583 }
3584 // Find a command line agent library and return its entry point for
3585 // -agentlib: -agentpath: -Xrun
3586 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3587 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3588 const char *on_load_symbols[],
3589 size_t num_symbol_entries) {
3590 OnLoadEntry_t on_load_entry = NULL;
3591 void *library = NULL;
3592
3593 if (!agent->valid()) {
3594 char buffer[JVM_MAXPATHLEN];
3595 char ebuf[1024] = "";
3596 const char *name = agent->name();
3597 const char *msg = "Could not find agent library ";
3598
3599 // First check to see if agent is statically linked into executable
3600 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3601 library = agent->os_lib();
3602 } else if (agent->is_absolute_path()) {
3603 library = os::dll_load(name, ebuf, sizeof ebuf);
3604 if (library == NULL) {
3605 const char *sub_msg = " in absolute path, with error: ";
3606 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3607 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3608 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3609 // If we can't find the agent, exit.
3610 vm_exit_during_initialization(buf, NULL);
3611 FREE_C_HEAP_ARRAY(char, buf);
3612 }
3613 } else {
3614 // Try to load the agent from the standard dll directory
3615 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3616 name)) {
3617 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3618 }
3619 if (library == NULL) { // Try the local directory
3620 char ns[1] = {0};
3621 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3622 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3623 }
3624 if (library == NULL) {
3625 const char *sub_msg = " on the library path, with error: ";
3626 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3627 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3628 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3629 // If we can't find the agent, exit.
3630 vm_exit_during_initialization(buf, NULL);
3631 FREE_C_HEAP_ARRAY(char, buf);
3632 }
3633 }
3634 }
3635 agent->set_os_lib(library);
3636 agent->set_valid();
3637 }
3638
3639 // Find the OnLoad function.
3640 on_load_entry =
3641 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3642 false,
3643 on_load_symbols,
3644 num_symbol_entries));
3645 return on_load_entry;
3646 }
3647
3648 // Find the JVM_OnLoad entry point
3649 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3650 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3651 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3652 }
3653
3654 // Find the Agent_OnLoad entry point
3655 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3656 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3657 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3658 }
3659
3660 // For backwards compatibility with -Xrun
3661 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3662 // treated like -agentpath:
3663 // Must be called before agent libraries are created
3664 void Threads::convert_vm_init_libraries_to_agents() {
3665 AgentLibrary* agent;
3666 AgentLibrary* next;
3667
3668 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3669 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3670 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3671
3672 // If there is an JVM_OnLoad function it will get called later,
3673 // otherwise see if there is an Agent_OnLoad
3674 if (on_load_entry == NULL) {
3675 on_load_entry = lookup_agent_on_load(agent);
3676 if (on_load_entry != NULL) {
3677 // switch it to the agent list -- so that Agent_OnLoad will be called,
3678 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3679 Arguments::convert_library_to_agent(agent);
3680 } else {
3681 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3682 }
3683 }
3684 }
3685 }
3686
3687 // Create agents for -agentlib: -agentpath: and converted -Xrun
3688 // Invokes Agent_OnLoad
3689 // Called very early -- before JavaThreads exist
3690 void Threads::create_vm_init_agents() {
3691 extern struct JavaVM_ main_vm;
3692 AgentLibrary* agent;
3693
3694 JvmtiExport::enter_onload_phase();
3695
3696 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3697 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3698
3699 if (on_load_entry != NULL) {
3700 // Invoke the Agent_OnLoad function
3701 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3702 if (err != JNI_OK) {
3703 vm_exit_during_initialization("agent library failed to init", agent->name());
3704 }
3705 } else {
3706 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3707 }
3708 }
3709 JvmtiExport::enter_primordial_phase();
3710 }
3711
3712 extern "C" {
3713 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3714 }
3715
3716 void Threads::shutdown_vm_agents() {
3717 // Send any Agent_OnUnload notifications
3718 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3719 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3720 extern struct JavaVM_ main_vm;
3721 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3722
3723 // Find the Agent_OnUnload function.
3724 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3725 os::find_agent_function(agent,
3726 false,
3727 on_unload_symbols,
3728 num_symbol_entries));
3729
3730 // Invoke the Agent_OnUnload function
3731 if (unload_entry != NULL) {
3732 JavaThread* thread = JavaThread::current();
3733 ThreadToNativeFromVM ttn(thread);
3734 HandleMark hm(thread);
3735 (*unload_entry)(&main_vm);
3736 }
3737 }
3738 }
3739
3740 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3741 // Invokes JVM_OnLoad
3742 void Threads::create_vm_init_libraries() {
3743 extern struct JavaVM_ main_vm;
3744 AgentLibrary* agent;
3745
3746 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3747 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3748
3749 if (on_load_entry != NULL) {
3750 // Invoke the JVM_OnLoad function
3751 JavaThread* thread = JavaThread::current();
3752 ThreadToNativeFromVM ttn(thread);
3753 HandleMark hm(thread);
3754 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3755 if (err != JNI_OK) {
3756 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3757 }
3758 } else {
3759 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3760 }
3761 }
3762 }
3763
3764 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3765 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3766
3767 JavaThread* java_thread = NULL;
3768 // Sequential search for now. Need to do better optimization later.
3769 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3770 oop tobj = thread->threadObj();
3771 if (!thread->is_exiting() &&
3772 tobj != NULL &&
3773 java_tid == java_lang_Thread::thread_id(tobj)) {
3774 java_thread = thread;
3775 break;
3776 }
3777 }
3778 return java_thread;
3779 }
3780
3781
3782 // Last thread running calls java.lang.Shutdown.shutdown()
3783 void JavaThread::invoke_shutdown_hooks() {
3784 HandleMark hm(this);
3785
3786 // We could get here with a pending exception, if so clear it now.
3787 if (this->has_pending_exception()) {
3788 this->clear_pending_exception();
3789 }
3790
3791 EXCEPTION_MARK;
3792 Klass* k =
3793 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3794 THREAD);
3795 if (k != NULL) {
3796 // SystemDictionary::resolve_or_null will return null if there was
3797 // an exception. If we cannot load the Shutdown class, just don't
3798 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3799 // and finalizers (if runFinalizersOnExit is set) won't be run.
3800 // Note that if a shutdown hook was registered or runFinalizersOnExit
3801 // was called, the Shutdown class would have already been loaded
3802 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3803 instanceKlassHandle shutdown_klass (THREAD, k);
3804 JavaValue result(T_VOID);
3805 JavaCalls::call_static(&result,
3806 shutdown_klass,
3807 vmSymbols::shutdown_method_name(),
3808 vmSymbols::void_method_signature(),
3809 THREAD);
3810 }
3811 CLEAR_PENDING_EXCEPTION;
3812 }
3813
3814 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3815 // the program falls off the end of main(). Another VM exit path is through
3816 // vm_exit() when the program calls System.exit() to return a value or when
3817 // there is a serious error in VM. The two shutdown paths are not exactly
3818 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3819 // and VM_Exit op at VM level.
3820 //
3821 // Shutdown sequence:
3822 // + Shutdown native memory tracking if it is on
3823 // + Wait until we are the last non-daemon thread to execute
3824 // <-- every thing is still working at this moment -->
3825 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3826 // shutdown hooks, run finalizers if finalization-on-exit
3827 // + Call before_exit(), prepare for VM exit
3828 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3829 // currently the only user of this mechanism is File.deleteOnExit())
3830 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3831 // post thread end and vm death events to JVMTI,
3832 // stop signal thread
3833 // + Call JavaThread::exit(), it will:
3834 // > release JNI handle blocks, remove stack guard pages
3835 // > remove this thread from Threads list
3836 // <-- no more Java code from this thread after this point -->
3837 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3838 // the compiler threads at safepoint
3839 // <-- do not use anything that could get blocked by Safepoint -->
3840 // + Disable tracing at JNI/JVM barriers
3841 // + Set _vm_exited flag for threads that are still running native code
3842 // + Delete this thread
3843 // + Call exit_globals()
3844 // > deletes tty
3845 // > deletes PerfMemory resources
3846 // + Return to caller
3847
3848 bool Threads::destroy_vm() {
3849 JavaThread* thread = JavaThread::current();
3850
3851 #ifdef ASSERT
3852 _vm_complete = false;
3853 #endif
3854 // Wait until we are the last non-daemon thread to execute
3855 { MutexLocker nu(Threads_lock);
3856 while (Threads::number_of_non_daemon_threads() > 1)
3857 // This wait should make safepoint checks, wait without a timeout,
3858 // and wait as a suspend-equivalent condition.
3859 //
3860 // Note: If the FlatProfiler is running and this thread is waiting
3861 // for another non-daemon thread to finish, then the FlatProfiler
3862 // is waiting for the external suspend request on this thread to
3863 // complete. wait_for_ext_suspend_completion() will eventually
3864 // timeout, but that takes time. Making this wait a suspend-
3865 // equivalent condition solves that timeout problem.
3866 //
3867 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3868 Mutex::_as_suspend_equivalent_flag);
3869 }
3870
3871 // Hang forever on exit if we are reporting an error.
3872 if (ShowMessageBoxOnError && is_error_reported()) {
3873 os::infinite_sleep();
3874 }
3875 os::wait_for_keypress_at_exit();
3876
3877 // run Java level shutdown hooks
3878 thread->invoke_shutdown_hooks();
3879
3880 before_exit(thread);
3881
3882 thread->exit(true);
3883
3884 // Stop VM thread.
3885 {
3886 // 4945125 The vm thread comes to a safepoint during exit.
3887 // GC vm_operations can get caught at the safepoint, and the
3888 // heap is unparseable if they are caught. Grab the Heap_lock
3889 // to prevent this. The GC vm_operations will not be able to
3890 // queue until after the vm thread is dead. After this point,
3891 // we'll never emerge out of the safepoint before the VM exits.
3892
3893 MutexLocker ml(Heap_lock);
3894
3895 VMThread::wait_for_vm_thread_exit();
3896 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3897 VMThread::destroy();
3898 }
3899
3900 // clean up ideal graph printers
3901 #if defined(COMPILER2) && !defined(PRODUCT)
3902 IdealGraphPrinter::clean_up();
3903 #endif
3904
3905 // Now, all Java threads are gone except daemon threads. Daemon threads
3906 // running Java code or in VM are stopped by the Safepoint. However,
3907 // daemon threads executing native code are still running. But they
3908 // will be stopped at native=>Java/VM barriers. Note that we can't
3909 // simply kill or suspend them, as it is inherently deadlock-prone.
3910
3911 #ifndef PRODUCT
3912 // disable function tracing at JNI/JVM barriers
3913 TraceJNICalls = false;
3914 TraceJVMCalls = false;
3915 TraceRuntimeCalls = false;
3916 #endif
3917
3918 VM_Exit::set_vm_exited();
3919
3920 notify_vm_shutdown();
3921
3922 delete thread;
3923
3924 // exit_globals() will delete tty
3925 exit_globals();
3926
3927 return true;
3928 }
3929
3930
3931 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3932 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3933 return is_supported_jni_version(version);
3934 }
3935
3936
3937 jboolean Threads::is_supported_jni_version(jint version) {
3938 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3939 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3940 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3941 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3942 return JNI_FALSE;
3943 }
3944
3945
3946 void Threads::add(JavaThread* p, bool force_daemon) {
3947 // The threads lock must be owned at this point
3948 assert_locked_or_safepoint(Threads_lock);
3949
3950 // See the comment for this method in thread.hpp for its purpose and
3951 // why it is called here.
3952 p->initialize_queues();
3953 p->set_next(_thread_list);
3954 _thread_list = p;
3955 _number_of_threads++;
3956 oop threadObj = p->threadObj();
3957 bool daemon = true;
3958 // Bootstrapping problem: threadObj can be null for initial
3959 // JavaThread (or for threads attached via JNI)
3960 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3961 _number_of_non_daemon_threads++;
3962 daemon = false;
3963 }
3964
3965 ThreadService::add_thread(p, daemon);
3966
3967 // Possible GC point.
3968 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
3969 }
3970
3971 void Threads::remove(JavaThread* p) {
3972 // Extra scope needed for Thread_lock, so we can check
3973 // that we do not remove thread without safepoint code notice
3974 { MutexLocker ml(Threads_lock);
3975
3976 assert(includes(p), "p must be present");
3977
3978 JavaThread* current = _thread_list;
3979 JavaThread* prev = NULL;
3980
3981 while (current != p) {
3982 prev = current;
3983 current = current->next();
3984 }
3985
3986 if (prev) {
3987 prev->set_next(current->next());
3988 } else {
3989 _thread_list = p->next();
3990 }
3991 _number_of_threads--;
3992 oop threadObj = p->threadObj();
3993 bool daemon = true;
3994 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
3995 _number_of_non_daemon_threads--;
3996 daemon = false;
3997
3998 // Only one thread left, do a notify on the Threads_lock so a thread waiting
3999 // on destroy_vm will wake up.
4000 if (number_of_non_daemon_threads() == 1) {
4001 Threads_lock->notify_all();
4002 }
4003 }
4004 ThreadService::remove_thread(p, daemon);
4005
4006 // Make sure that safepoint code disregard this thread. This is needed since
4007 // the thread might mess around with locks after this point. This can cause it
4008 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4009 // of this thread since it is removed from the queue.
4010 p->set_terminated_value();
4011 } // unlock Threads_lock
4012
4013 // Since Events::log uses a lock, we grab it outside the Threads_lock
4014 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4015 }
4016
4017 // Threads_lock must be held when this is called (or must be called during a safepoint)
4018 bool Threads::includes(JavaThread* p) {
4019 assert(Threads_lock->is_locked(), "sanity check");
4020 ALL_JAVA_THREADS(q) {
4021 if (q == p) {
4022 return true;
4023 }
4024 }
4025 return false;
4026 }
4027
4028 // Operations on the Threads list for GC. These are not explicitly locked,
4029 // but the garbage collector must provide a safe context for them to run.
4030 // In particular, these things should never be called when the Threads_lock
4031 // is held by some other thread. (Note: the Safepoint abstraction also
4032 // uses the Threads_lock to guarantee this property. It also makes sure that
4033 // all threads gets blocked when exiting or starting).
4034
4035 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4036 ALL_JAVA_THREADS(p) {
4037 p->oops_do(f, cld_f, cf);
4038 }
4039 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4040 }
4041
4042 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4043 // Introduce a mechanism allowing parallel threads to claim threads as
4044 // root groups. Overhead should be small enough to use all the time,
4045 // even in sequential code.
4046 SharedHeap* sh = SharedHeap::heap();
4047 // Cannot yet substitute active_workers for n_par_threads
4048 // because of G1CollectedHeap::verify() use of
4049 // SharedHeap::process_roots(). n_par_threads == 0 will
4050 // turn off parallelism in process_roots while active_workers
4051 // is being used for parallelism elsewhere.
4052 bool is_par = sh->n_par_threads() > 0;
4053 assert(!is_par ||
4054 (SharedHeap::heap()->n_par_threads() ==
4055 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4056 int cp = SharedHeap::heap()->strong_roots_parity();
4057 ALL_JAVA_THREADS(p) {
4058 if (p->claim_oops_do(is_par, cp)) {
4059 p->oops_do(f, cld_f, cf);
4060 }
4061 }
4062 VMThread* vmt = VMThread::vm_thread();
4063 if (vmt->claim_oops_do(is_par, cp)) {
4064 vmt->oops_do(f, cld_f, cf);
4065 }
4066 }
4067
4068 #if INCLUDE_ALL_GCS
4069 // Used by ParallelScavenge
4070 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4071 ALL_JAVA_THREADS(p) {
4072 q->enqueue(new ThreadRootsTask(p));
4073 }
4074 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4075 }
4076
4077 // Used by Parallel Old
4078 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4079 ALL_JAVA_THREADS(p) {
4080 q->enqueue(new ThreadRootsMarkingTask(p));
4081 }
4082 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4083 }
4084 #endif // INCLUDE_ALL_GCS
4085
4086 void Threads::nmethods_do(CodeBlobClosure* cf) {
4087 ALL_JAVA_THREADS(p) {
4088 p->nmethods_do(cf);
4089 }
4090 VMThread::vm_thread()->nmethods_do(cf);
4091 }
4092
4093 void Threads::metadata_do(void f(Metadata*)) {
4094 ALL_JAVA_THREADS(p) {
4095 p->metadata_do(f);
4096 }
4097 }
4098
4099 void Threads::deoptimized_wrt_marked_nmethods() {
4100 ALL_JAVA_THREADS(p) {
4101 p->deoptimized_wrt_marked_nmethods();
4102 }
4103 }
4104
4105
4106 // Get count Java threads that are waiting to enter the specified monitor.
4107 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4108 address monitor,
4109 bool doLock) {
4110 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4111 "must grab Threads_lock or be at safepoint");
4112 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4113
4114 int i = 0;
4115 {
4116 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4117 ALL_JAVA_THREADS(p) {
4118 if (p->is_Compiler_thread()) continue;
4119
4120 address pending = (address)p->current_pending_monitor();
4121 if (pending == monitor) { // found a match
4122 if (i < count) result->append(p); // save the first count matches
4123 i++;
4124 }
4125 }
4126 }
4127 return result;
4128 }
4129
4130
4131 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4132 bool doLock) {
4133 assert(doLock ||
4134 Threads_lock->owned_by_self() ||
4135 SafepointSynchronize::is_at_safepoint(),
4136 "must grab Threads_lock or be at safepoint");
4137
4138 // NULL owner means not locked so we can skip the search
4139 if (owner == NULL) return NULL;
4140
4141 {
4142 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4143 ALL_JAVA_THREADS(p) {
4144 // first, see if owner is the address of a Java thread
4145 if (owner == (address)p) return p;
4146 }
4147 }
4148 // Cannot assert on lack of success here since this function may be
4149 // used by code that is trying to report useful problem information
4150 // like deadlock detection.
4151 if (UseHeavyMonitors) return NULL;
4152
4153 // If we didn't find a matching Java thread and we didn't force use of
4154 // heavyweight monitors, then the owner is the stack address of the
4155 // Lock Word in the owning Java thread's stack.
4156 //
4157 JavaThread* the_owner = NULL;
4158 {
4159 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4160 ALL_JAVA_THREADS(q) {
4161 if (q->is_lock_owned(owner)) {
4162 the_owner = q;
4163 break;
4164 }
4165 }
4166 }
4167 // cannot assert on lack of success here; see above comment
4168 return the_owner;
4169 }
4170
4171 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4172 void Threads::print_on(outputStream* st, bool print_stacks,
4173 bool internal_format, bool print_concurrent_locks) {
4174 char buf[32];
4175 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4176
4177 st->print_cr("Full thread dump %s (%s %s):",
4178 Abstract_VM_Version::vm_name(),
4179 Abstract_VM_Version::vm_release(),
4180 Abstract_VM_Version::vm_info_string());
4181 st->cr();
4182
4183 #if INCLUDE_ALL_GCS
4184 // Dump concurrent locks
4185 ConcurrentLocksDump concurrent_locks;
4186 if (print_concurrent_locks) {
4187 concurrent_locks.dump_at_safepoint();
4188 }
4189 #endif // INCLUDE_ALL_GCS
4190
4191 ALL_JAVA_THREADS(p) {
4192 ResourceMark rm;
4193 p->print_on(st);
4194 if (print_stacks) {
4195 if (internal_format) {
4196 p->trace_stack();
4197 } else {
4198 p->print_stack_on(st);
4199 }
4200 }
4201 st->cr();
4202 #if INCLUDE_ALL_GCS
4203 if (print_concurrent_locks) {
4204 concurrent_locks.print_locks_on(p, st);
4205 }
4206 #endif // INCLUDE_ALL_GCS
4207 }
4208
4209 VMThread::vm_thread()->print_on(st);
4210 st->cr();
4211 Universe::heap()->print_gc_threads_on(st);
4212 WatcherThread* wt = WatcherThread::watcher_thread();
4213 if (wt != NULL) {
4214 wt->print_on(st);
4215 st->cr();
4216 }
4217 CompileBroker::print_compiler_threads_on(st);
4218 st->flush();
4219 }
4220
4221 // Threads::print_on_error() is called by fatal error handler. It's possible
4222 // that VM is not at safepoint and/or current thread is inside signal handler.
4223 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4224 // memory (even in resource area), it might deadlock the error handler.
4225 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4226 int buflen) {
4227 bool found_current = false;
4228 st->print_cr("Java Threads: ( => current thread )");
4229 ALL_JAVA_THREADS(thread) {
4230 bool is_current = (current == thread);
4231 found_current = found_current || is_current;
4232
4233 st->print("%s", is_current ? "=>" : " ");
4234
4235 st->print(PTR_FORMAT, thread);
4236 st->print(" ");
4237 thread->print_on_error(st, buf, buflen);
4238 st->cr();
4239 }
4240 st->cr();
4241
4242 st->print_cr("Other Threads:");
4243 if (VMThread::vm_thread()) {
4244 bool is_current = (current == VMThread::vm_thread());
4245 found_current = found_current || is_current;
4246 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4247
4248 st->print(PTR_FORMAT, VMThread::vm_thread());
4249 st->print(" ");
4250 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4251 st->cr();
4252 }
4253 WatcherThread* wt = WatcherThread::watcher_thread();
4254 if (wt != NULL) {
4255 bool is_current = (current == wt);
4256 found_current = found_current || is_current;
4257 st->print("%s", is_current ? "=>" : " ");
4258
4259 st->print(PTR_FORMAT, wt);
4260 st->print(" ");
4261 wt->print_on_error(st, buf, buflen);
4262 st->cr();
4263 }
4264 if (!found_current) {
4265 st->cr();
4266 st->print("=>" PTR_FORMAT " (exited) ", current);
4267 current->print_on_error(st, buf, buflen);
4268 st->cr();
4269 }
4270 }
4271
4272 // Internal SpinLock and Mutex
4273 // Based on ParkEvent
4274
4275 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4276 //
4277 // We employ SpinLocks _only for low-contention, fixed-length
4278 // short-duration critical sections where we're concerned
4279 // about native mutex_t or HotSpot Mutex:: latency.
4280 // The mux construct provides a spin-then-block mutual exclusion
4281 // mechanism.
4282 //
4283 // Testing has shown that contention on the ListLock guarding gFreeList
4284 // is common. If we implement ListLock as a simple SpinLock it's common
4285 // for the JVM to devolve to yielding with little progress. This is true
4286 // despite the fact that the critical sections protected by ListLock are
4287 // extremely short.
4288 //
4289 // TODO-FIXME: ListLock should be of type SpinLock.
4290 // We should make this a 1st-class type, integrated into the lock
4291 // hierarchy as leaf-locks. Critically, the SpinLock structure
4292 // should have sufficient padding to avoid false-sharing and excessive
4293 // cache-coherency traffic.
4294
4295
4296 typedef volatile int SpinLockT;
4297
4298 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4299 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4300 return; // normal fast-path return
4301 }
4302
4303 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4304 TEVENT(SpinAcquire - ctx);
4305 int ctr = 0;
4306 int Yields = 0;
4307 for (;;) {
4308 while (*adr != 0) {
4309 ++ctr;
4310 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4311 if (Yields > 5) {
4312 os::naked_short_sleep(1);
4313 } else {
4314 os::naked_yield();
4315 ++Yields;
4316 }
4317 } else {
4318 SpinPause();
4319 }
4320 }
4321 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4322 }
4323 }
4324
4325 void Thread::SpinRelease(volatile int * adr) {
4326 assert(*adr != 0, "invariant");
4327 OrderAccess::fence(); // guarantee at least release consistency.
4328 // Roach-motel semantics.
4329 // It's safe if subsequent LDs and STs float "up" into the critical section,
4330 // but prior LDs and STs within the critical section can't be allowed
4331 // to reorder or float past the ST that releases the lock.
4332 // Loads and stores in the critical section - which appear in program
4333 // order before the store that releases the lock - must also appear
4334 // before the store that releases the lock in memory visibility order.
4335 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4336 // the ST of 0 into the lock-word which releases the lock, so fence
4337 // more than covers this on all platforms.
4338 *adr = 0;
4339 }
4340
4341 // muxAcquire and muxRelease:
4342 //
4343 // * muxAcquire and muxRelease support a single-word lock-word construct.
4344 // The LSB of the word is set IFF the lock is held.
4345 // The remainder of the word points to the head of a singly-linked list
4346 // of threads blocked on the lock.
4347 //
4348 // * The current implementation of muxAcquire-muxRelease uses its own
4349 // dedicated Thread._MuxEvent instance. If we're interested in
4350 // minimizing the peak number of extant ParkEvent instances then
4351 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4352 // as certain invariants were satisfied. Specifically, care would need
4353 // to be taken with regards to consuming unpark() "permits".
4354 // A safe rule of thumb is that a thread would never call muxAcquire()
4355 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4356 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4357 // consume an unpark() permit intended for monitorenter, for instance.
4358 // One way around this would be to widen the restricted-range semaphore
4359 // implemented in park(). Another alternative would be to provide
4360 // multiple instances of the PlatformEvent() for each thread. One
4361 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4362 //
4363 // * Usage:
4364 // -- Only as leaf locks
4365 // -- for short-term locking only as muxAcquire does not perform
4366 // thread state transitions.
4367 //
4368 // Alternatives:
4369 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4370 // but with parking or spin-then-park instead of pure spinning.
4371 // * Use Taura-Oyama-Yonenzawa locks.
4372 // * It's possible to construct a 1-0 lock if we encode the lockword as
4373 // (List,LockByte). Acquire will CAS the full lockword while Release
4374 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4375 // acquiring threads use timers (ParkTimed) to detect and recover from
4376 // the stranding window. Thread/Node structures must be aligned on 256-byte
4377 // boundaries by using placement-new.
4378 // * Augment MCS with advisory back-link fields maintained with CAS().
4379 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4380 // The validity of the backlinks must be ratified before we trust the value.
4381 // If the backlinks are invalid the exiting thread must back-track through the
4382 // the forward links, which are always trustworthy.
4383 // * Add a successor indication. The LockWord is currently encoded as
4384 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4385 // to provide the usual futile-wakeup optimization.
4386 // See RTStt for details.
4387 // * Consider schedctl.sc_nopreempt to cover the critical section.
4388 //
4389
4390
4391 typedef volatile intptr_t MutexT; // Mux Lock-word
4392 enum MuxBits { LOCKBIT = 1 };
4393
4394 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4395 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4396 if (w == 0) return;
4397 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4398 return;
4399 }
4400
4401 TEVENT(muxAcquire - Contention);
4402 ParkEvent * const Self = Thread::current()->_MuxEvent;
4403 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4404 for (;;) {
4405 int its = (os::is_MP() ? 100 : 0) + 1;
4406
4407 // Optional spin phase: spin-then-park strategy
4408 while (--its >= 0) {
4409 w = *Lock;
4410 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4411 return;
4412 }
4413 }
4414
4415 Self->reset();
4416 Self->OnList = intptr_t(Lock);
4417 // The following fence() isn't _strictly necessary as the subsequent
4418 // CAS() both serializes execution and ratifies the fetched *Lock value.
4419 OrderAccess::fence();
4420 for (;;) {
4421 w = *Lock;
4422 if ((w & LOCKBIT) == 0) {
4423 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4424 Self->OnList = 0; // hygiene - allows stronger asserts
4425 return;
4426 }
4427 continue; // Interference -- *Lock changed -- Just retry
4428 }
4429 assert(w & LOCKBIT, "invariant");
4430 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4431 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4432 }
4433
4434 while (Self->OnList != 0) {
4435 Self->park();
4436 }
4437 }
4438 }
4439
4440 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4441 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4442 if (w == 0) return;
4443 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4444 return;
4445 }
4446
4447 TEVENT(muxAcquire - Contention);
4448 ParkEvent * ReleaseAfter = NULL;
4449 if (ev == NULL) {
4450 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4451 }
4452 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4453 for (;;) {
4454 guarantee(ev->OnList == 0, "invariant");
4455 int its = (os::is_MP() ? 100 : 0) + 1;
4456
4457 // Optional spin phase: spin-then-park strategy
4458 while (--its >= 0) {
4459 w = *Lock;
4460 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4461 if (ReleaseAfter != NULL) {
4462 ParkEvent::Release(ReleaseAfter);
4463 }
4464 return;
4465 }
4466 }
4467
4468 ev->reset();
4469 ev->OnList = intptr_t(Lock);
4470 // The following fence() isn't _strictly necessary as the subsequent
4471 // CAS() both serializes execution and ratifies the fetched *Lock value.
4472 OrderAccess::fence();
4473 for (;;) {
4474 w = *Lock;
4475 if ((w & LOCKBIT) == 0) {
4476 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4477 ev->OnList = 0;
4478 // We call ::Release while holding the outer lock, thus
4479 // artificially lengthening the critical section.
4480 // Consider deferring the ::Release() until the subsequent unlock(),
4481 // after we've dropped the outer lock.
4482 if (ReleaseAfter != NULL) {
4483 ParkEvent::Release(ReleaseAfter);
4484 }
4485 return;
4486 }
4487 continue; // Interference -- *Lock changed -- Just retry
4488 }
4489 assert(w & LOCKBIT, "invariant");
4490 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4491 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4492 }
4493
4494 while (ev->OnList != 0) {
4495 ev->park();
4496 }
4497 }
4498 }
4499
4500 // Release() must extract a successor from the list and then wake that thread.
4501 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4502 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4503 // Release() would :
4504 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4505 // (B) Extract a successor from the private list "in-hand"
4506 // (C) attempt to CAS() the residual back into *Lock over null.
4507 // If there were any newly arrived threads and the CAS() would fail.
4508 // In that case Release() would detach the RATs, re-merge the list in-hand
4509 // with the RATs and repeat as needed. Alternately, Release() might
4510 // detach and extract a successor, but then pass the residual list to the wakee.
4511 // The wakee would be responsible for reattaching and remerging before it
4512 // competed for the lock.
4513 //
4514 // Both "pop" and DMR are immune from ABA corruption -- there can be
4515 // multiple concurrent pushers, but only one popper or detacher.
4516 // This implementation pops from the head of the list. This is unfair,
4517 // but tends to provide excellent throughput as hot threads remain hot.
4518 // (We wake recently run threads first).
4519 //
4520 // All paths through muxRelease() will execute a CAS.
4521 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4522 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4523 // executed within the critical section are complete and globally visible before the
4524 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4525 void Thread::muxRelease(volatile intptr_t * Lock) {
4526 for (;;) {
4527 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4528 assert(w & LOCKBIT, "invariant");
4529 if (w == LOCKBIT) return;
4530 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4531 assert(List != NULL, "invariant");
4532 assert(List->OnList == intptr_t(Lock), "invariant");
4533 ParkEvent * const nxt = List->ListNext;
4534 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4535
4536 // The following CAS() releases the lock and pops the head element.
4537 // The CAS() also ratifies the previously fetched lock-word value.
4538 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4539 continue;
4540 }
4541 List->OnList = 0;
4542 OrderAccess::fence();
4543 List->unpark();
4544 return;
4545 }
4546 }
4547
4548
4549 void Threads::verify() {
4550 ALL_JAVA_THREADS(p) {
4551 p->verify();
4552 }
4553 VMThread* thread = VMThread::vm_thread();
4554 if (thread != NULL) thread->verify();
4555 }