1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/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 "oops/verifyOopClosure.hpp"
46 #include "prims/jvm_misc.hpp"
47 #include "prims/jvmtiExport.hpp"
48 #include "prims/jvmtiThreadState.hpp"
49 #include "prims/privilegedStack.hpp"
50 #include "runtime/arguments.hpp"
51 #include "runtime/atomic.inline.hpp"
52 #include "runtime/biasedLocking.hpp"
53 #include "runtime/deoptimization.hpp"
54 #include "runtime/fprofiler.hpp"
55 #include "runtime/frame.inline.hpp"
56 #include "runtime/init.hpp"
57 #include "runtime/interfaceSupport.hpp"
58 #include "runtime/java.hpp"
59 #include "runtime/javaCalls.hpp"
60 #include "runtime/jniPeriodicChecker.hpp"
61 #include "runtime/memprofiler.hpp"
62 #include "runtime/mutexLocker.hpp"
63 #include "runtime/objectMonitor.hpp"
64 #include "runtime/orderAccess.inline.hpp"
65 #include "runtime/osThread.hpp"
66 #include "runtime/safepoint.hpp"
67 #include "runtime/sharedRuntime.hpp"
68 #include "runtime/statSampler.hpp"
69 #include "runtime/stubRoutines.hpp"
70 #include "runtime/sweeper.hpp"
71 #include "runtime/task.hpp"
72 #include "runtime/thread.inline.hpp"
73 #include "runtime/threadCritical.hpp"
74 #include "runtime/threadLocalStorage.hpp"
75 #include "runtime/vframe.hpp"
76 #include "runtime/vframeArray.hpp"
77 #include "runtime/vframe_hp.hpp"
78 #include "runtime/vmThread.hpp"
79 #include "runtime/vm_operations.hpp"
80 #include "runtime/vm_version.hpp"
81 #include "services/attachListener.hpp"
82 #include "services/management.hpp"
83 #include "services/memTracker.hpp"
84 #include "services/threadService.hpp"
85 #include "trace/tracing.hpp"
86 #include "trace/traceMacros.hpp"
87 #include "utilities/defaultStream.hpp"
88 #include "utilities/dtrace.hpp"
89 #include "utilities/events.hpp"
90 #include "utilities/macros.hpp"
91 #include "utilities/preserveException.hpp"
92 #include "utilities/workgroup.hpp"
93 #if INCLUDE_ALL_GCS
94 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
95 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
96 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
97 #endif // INCLUDE_ALL_GCS
98 #ifdef COMPILER1
99 #include "c1/c1_Compiler.hpp"
100 #endif
101 #ifdef COMPILER2
102 #include "opto/c2compiler.hpp"
103 #include "opto/idealGraphPrinter.hpp"
104 #endif
105 #if INCLUDE_RTM_OPT
106 #include "runtime/rtmLocking.hpp"
107 #endif
108
109 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
110
111 #ifdef DTRACE_ENABLED
112
113 // Only bother with this argument setup if dtrace is available
114
115 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
116 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
117
118 #define DTRACE_THREAD_PROBE(probe, javathread) \
119 { \
120 ResourceMark rm(this); \
121 int len = 0; \
122 const char* name = (javathread)->get_thread_name(); \
123 len = strlen(name); \
124 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
125 (char *) name, len, \
126 java_lang_Thread::thread_id((javathread)->threadObj()), \
127 (uintptr_t) (javathread)->osthread()->thread_id(), \
128 java_lang_Thread::is_daemon((javathread)->threadObj())); \
129 }
130
131 #else // ndef DTRACE_ENABLED
132
133 #define DTRACE_THREAD_PROBE(probe, javathread)
134
135 #endif // ndef DTRACE_ENABLED
136
137
138 // Class hierarchy
139 // - Thread
140 // - VMThread
141 // - WatcherThread
142 // - ConcurrentMarkSweepThread
143 // - JavaThread
144 // - CompilerThread
145
146 // ======= Thread ========
147 // Support for forcing alignment of thread objects for biased locking
148 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
149 if (UseBiasedLocking) {
150 const int alignment = markOopDesc::biased_lock_alignment;
151 size_t aligned_size = size + (alignment - sizeof(intptr_t));
152 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
153 : AllocateHeap(aligned_size, flags, CURRENT_PC,
154 AllocFailStrategy::RETURN_NULL);
155 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
156 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
157 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
158 "JavaThread alignment code overflowed allocated storage");
159 if (TraceBiasedLocking) {
160 if (aligned_addr != real_malloc_addr) {
161 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
162 real_malloc_addr, aligned_addr);
163 }
164 }
165 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
166 return aligned_addr;
167 } else {
168 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
169 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
170 }
171 }
172
173 void Thread::operator delete(void* p) {
174 if (UseBiasedLocking) {
175 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
176 FreeHeap(real_malloc_addr);
177 } else {
178 FreeHeap(p);
179 }
180 }
181
182
183 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
184 // JavaThread
185
186
187 Thread::Thread() {
188 // stack and get_thread
189 set_stack_base(NULL);
190 set_stack_size(0);
191 set_self_raw_id(0);
192 set_lgrp_id(-1);
193 DEBUG_ONLY(clear_suspendible_thread();)
194
195 // allocated data structures
196 set_osthread(NULL);
197 set_resource_area(new (mtThread)ResourceArea());
198 DEBUG_ONLY(_current_resource_mark = NULL;)
199 set_handle_area(new (mtThread) HandleArea(NULL));
200 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
201 set_active_handles(NULL);
202 set_free_handle_block(NULL);
203 set_last_handle_mark(NULL);
204
205 // This initial value ==> never claimed.
206 _oops_do_parity = 0;
207
208 // the handle mark links itself to last_handle_mark
209 new HandleMark(this);
210
211 // plain initialization
212 debug_only(_owned_locks = NULL;)
213 debug_only(_allow_allocation_count = 0;)
214 NOT_PRODUCT(_allow_safepoint_count = 0;)
215 NOT_PRODUCT(_skip_gcalot = false;)
216 _jvmti_env_iteration_count = 0;
217 set_allocated_bytes(0);
218 _vm_operation_started_count = 0;
219 _vm_operation_completed_count = 0;
220 _current_pending_monitor = NULL;
221 _current_pending_monitor_is_from_java = true;
222 _current_waiting_monitor = NULL;
223 _num_nested_signal = 0;
224 omFreeList = NULL;
225 omFreeCount = 0;
226 omFreeProvision = 32;
227 omInUseList = NULL;
228 omInUseCount = 0;
229
230 #ifdef ASSERT
231 _visited_for_critical_count = false;
232 #endif
233
234 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
235 Monitor::_safepoint_check_sometimes);
236 _suspend_flags = 0;
237
238 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
239 _hashStateX = os::random();
240 _hashStateY = 842502087;
241 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
242 _hashStateW = 273326509;
243
244 _OnTrap = 0;
245 _schedctl = NULL;
246 _Stalled = 0;
247 _TypeTag = 0x2BAD;
248
249 // Many of the following fields are effectively final - immutable
250 // Note that nascent threads can't use the Native Monitor-Mutex
251 // construct until the _MutexEvent is initialized ...
252 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
253 // we might instead use a stack of ParkEvents that we could provision on-demand.
254 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
255 // and ::Release()
256 _ParkEvent = ParkEvent::Allocate(this);
257 _SleepEvent = ParkEvent::Allocate(this);
258 _MutexEvent = ParkEvent::Allocate(this);
259 _MuxEvent = ParkEvent::Allocate(this);
260
261 #ifdef CHECK_UNHANDLED_OOPS
262 if (CheckUnhandledOops) {
263 _unhandled_oops = new UnhandledOops(this);
264 }
265 #endif // CHECK_UNHANDLED_OOPS
266 #ifdef ASSERT
267 if (UseBiasedLocking) {
268 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
269 assert(this == _real_malloc_address ||
270 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
271 "bug in forced alignment of thread objects");
272 }
273 #endif // ASSERT
274 }
275
276 // Non-inlined version to be used where thread.inline.hpp shouldn't be included.
277 Thread* Thread::current_noinline() {
278 return Thread::current();
279 }
280
281 void Thread::initialize_thread_local_storage() {
282 // Note: Make sure this method only calls
283 // non-blocking operations. Otherwise, it might not work
284 // with the thread-startup/safepoint interaction.
285
286 // During Java thread startup, safepoint code should allow this
287 // method to complete because it may need to allocate memory to
288 // store information for the new thread.
289
290 // initialize structure dependent on thread local storage
291 ThreadLocalStorage::set_thread(this);
292 }
293
294 void Thread::record_stack_base_and_size() {
295 set_stack_base(os::current_stack_base());
296 set_stack_size(os::current_stack_size());
297 if (is_Java_thread()) {
298 ((JavaThread*) this)->set_stack_overflow_limit();
299 }
300 // CR 7190089: on Solaris, primordial thread's stack is adjusted
301 // in initialize_thread(). Without the adjustment, stack size is
302 // incorrect if stack is set to unlimited (ulimit -s unlimited).
303 // So far, only Solaris has real implementation of initialize_thread().
304 //
305 // set up any platform-specific state.
306 os::initialize_thread(this);
307
308 #if INCLUDE_NMT
309 // record thread's native stack, stack grows downward
310 address stack_low_addr = stack_base() - stack_size();
311 MemTracker::record_thread_stack(stack_low_addr, stack_size());
312 #endif // INCLUDE_NMT
313 }
314
315
316 Thread::~Thread() {
317 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
318 ObjectSynchronizer::omFlush(this);
319
320 EVENT_THREAD_DESTRUCT(this);
321
322 // stack_base can be NULL if the thread is never started or exited before
323 // record_stack_base_and_size called. Although, we would like to ensure
324 // that all started threads do call record_stack_base_and_size(), there is
325 // not proper way to enforce that.
326 #if INCLUDE_NMT
327 if (_stack_base != NULL) {
328 address low_stack_addr = stack_base() - stack_size();
329 MemTracker::release_thread_stack(low_stack_addr, stack_size());
330 #ifdef ASSERT
331 set_stack_base(NULL);
332 #endif
333 }
334 #endif // INCLUDE_NMT
335
336 // deallocate data structures
337 delete resource_area();
338 // since the handle marks are using the handle area, we have to deallocated the root
339 // handle mark before deallocating the thread's handle area,
340 assert(last_handle_mark() != NULL, "check we have an element");
341 delete last_handle_mark();
342 assert(last_handle_mark() == NULL, "check we have reached the end");
343
344 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
345 // We NULL out the fields for good hygiene.
346 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
347 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
348 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
349 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
350
351 delete handle_area();
352 delete metadata_handles();
353
354 // osthread() can be NULL, if creation of thread failed.
355 if (osthread() != NULL) os::free_thread(osthread());
356
357 delete _SR_lock;
358
359 // clear thread local storage if the Thread is deleting itself
360 if (this == Thread::current()) {
361 ThreadLocalStorage::set_thread(NULL);
362 } else {
363 // In the case where we're not the current thread, invalidate all the
364 // caches in case some code tries to get the current thread or the
365 // thread that was destroyed, and gets stale information.
366 ThreadLocalStorage::invalidate_all();
367 }
368 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
369 }
370
371 // NOTE: dummy function for assertion purpose.
372 void Thread::run() {
373 ShouldNotReachHere();
374 }
375
376 #ifdef ASSERT
377 // Private method to check for dangling thread pointer
378 void check_for_dangling_thread_pointer(Thread *thread) {
379 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
380 "possibility of dangling Thread pointer");
381 }
382 #endif
383
384 ThreadPriority Thread::get_priority(const Thread* const thread) {
385 ThreadPriority priority;
386 // Can return an error!
387 (void)os::get_priority(thread, priority);
388 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
389 return priority;
390 }
391
392 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
393 debug_only(check_for_dangling_thread_pointer(thread);)
394 // Can return an error!
395 (void)os::set_priority(thread, priority);
396 }
397
398
399 void Thread::start(Thread* thread) {
400 // Start is different from resume in that its safety is guaranteed by context or
401 // being called from a Java method synchronized on the Thread object.
402 if (!DisableStartThread) {
403 if (thread->is_Java_thread()) {
404 // Initialize the thread state to RUNNABLE before starting this thread.
405 // Can not set it after the thread started because we do not know the
406 // exact thread state at that time. It could be in MONITOR_WAIT or
407 // in SLEEPING or some other state.
408 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
409 java_lang_Thread::RUNNABLE);
410 }
411 os::start_thread(thread);
412 }
413 }
414
415 // Enqueue a VM_Operation to do the job for us - sometime later
416 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
417 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
418 VMThread::execute(vm_stop);
419 }
420
421
422 // Check if an external suspend request has completed (or has been
423 // cancelled). Returns true if the thread is externally suspended and
424 // false otherwise.
425 //
426 // The bits parameter returns information about the code path through
427 // the routine. Useful for debugging:
428 //
429 // set in is_ext_suspend_completed():
430 // 0x00000001 - routine was entered
431 // 0x00000010 - routine return false at end
432 // 0x00000100 - thread exited (return false)
433 // 0x00000200 - suspend request cancelled (return false)
434 // 0x00000400 - thread suspended (return true)
435 // 0x00001000 - thread is in a suspend equivalent state (return true)
436 // 0x00002000 - thread is native and walkable (return true)
437 // 0x00004000 - thread is native_trans and walkable (needed retry)
438 //
439 // set in wait_for_ext_suspend_completion():
440 // 0x00010000 - routine was entered
441 // 0x00020000 - suspend request cancelled before loop (return false)
442 // 0x00040000 - thread suspended before loop (return true)
443 // 0x00080000 - suspend request cancelled in loop (return false)
444 // 0x00100000 - thread suspended in loop (return true)
445 // 0x00200000 - suspend not completed during retry loop (return false)
446
447 // Helper class for tracing suspend wait debug bits.
448 //
449 // 0x00000100 indicates that the target thread exited before it could
450 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
451 // 0x00080000 each indicate a cancelled suspend request so they don't
452 // count as wait failures either.
453 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
454
455 class TraceSuspendDebugBits : public StackObj {
456 private:
457 JavaThread * jt;
458 bool is_wait;
459 bool called_by_wait; // meaningful when !is_wait
460 uint32_t * bits;
461
462 public:
463 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
464 uint32_t *_bits) {
465 jt = _jt;
466 is_wait = _is_wait;
467 called_by_wait = _called_by_wait;
468 bits = _bits;
469 }
470
471 ~TraceSuspendDebugBits() {
472 if (!is_wait) {
473 #if 1
474 // By default, don't trace bits for is_ext_suspend_completed() calls.
475 // That trace is very chatty.
476 return;
477 #else
478 if (!called_by_wait) {
479 // If tracing for is_ext_suspend_completed() is enabled, then only
480 // trace calls to it from wait_for_ext_suspend_completion()
481 return;
482 }
483 #endif
484 }
485
486 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
487 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
488 MutexLocker ml(Threads_lock); // needed for get_thread_name()
489 ResourceMark rm;
490
491 tty->print_cr(
492 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
493 jt->get_thread_name(), *bits);
494
495 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
496 }
497 }
498 }
499 };
500 #undef DEBUG_FALSE_BITS
501
502
503 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
504 uint32_t *bits) {
505 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
506
507 bool did_trans_retry = false; // only do thread_in_native_trans retry once
508 bool do_trans_retry; // flag to force the retry
509
510 *bits |= 0x00000001;
511
512 do {
513 do_trans_retry = false;
514
515 if (is_exiting()) {
516 // Thread is in the process of exiting. This is always checked
517 // first to reduce the risk of dereferencing a freed JavaThread.
518 *bits |= 0x00000100;
519 return false;
520 }
521
522 if (!is_external_suspend()) {
523 // Suspend request is cancelled. This is always checked before
524 // is_ext_suspended() to reduce the risk of a rogue resume
525 // confusing the thread that made the suspend request.
526 *bits |= 0x00000200;
527 return false;
528 }
529
530 if (is_ext_suspended()) {
531 // thread is suspended
532 *bits |= 0x00000400;
533 return true;
534 }
535
536 // Now that we no longer do hard suspends of threads running
537 // native code, the target thread can be changing thread state
538 // while we are in this routine:
539 //
540 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
541 //
542 // We save a copy of the thread state as observed at this moment
543 // and make our decision about suspend completeness based on the
544 // copy. This closes the race where the thread state is seen as
545 // _thread_in_native_trans in the if-thread_blocked check, but is
546 // seen as _thread_blocked in if-thread_in_native_trans check.
547 JavaThreadState save_state = thread_state();
548
549 if (save_state == _thread_blocked && is_suspend_equivalent()) {
550 // If the thread's state is _thread_blocked and this blocking
551 // condition is known to be equivalent to a suspend, then we can
552 // consider the thread to be externally suspended. This means that
553 // the code that sets _thread_blocked has been modified to do
554 // self-suspension if the blocking condition releases. We also
555 // used to check for CONDVAR_WAIT here, but that is now covered by
556 // the _thread_blocked with self-suspension check.
557 //
558 // Return true since we wouldn't be here unless there was still an
559 // external suspend request.
560 *bits |= 0x00001000;
561 return true;
562 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
563 // Threads running native code will self-suspend on native==>VM/Java
564 // transitions. If its stack is walkable (should always be the case
565 // unless this function is called before the actual java_suspend()
566 // call), then the wait is done.
567 *bits |= 0x00002000;
568 return true;
569 } else if (!called_by_wait && !did_trans_retry &&
570 save_state == _thread_in_native_trans &&
571 frame_anchor()->walkable()) {
572 // The thread is transitioning from thread_in_native to another
573 // thread state. check_safepoint_and_suspend_for_native_trans()
574 // will force the thread to self-suspend. If it hasn't gotten
575 // there yet we may have caught the thread in-between the native
576 // code check above and the self-suspend. Lucky us. If we were
577 // called by wait_for_ext_suspend_completion(), then it
578 // will be doing the retries so we don't have to.
579 //
580 // Since we use the saved thread state in the if-statement above,
581 // there is a chance that the thread has already transitioned to
582 // _thread_blocked by the time we get here. In that case, we will
583 // make a single unnecessary pass through the logic below. This
584 // doesn't hurt anything since we still do the trans retry.
585
586 *bits |= 0x00004000;
587
588 // Once the thread leaves thread_in_native_trans for another
589 // thread state, we break out of this retry loop. We shouldn't
590 // need this flag to prevent us from getting back here, but
591 // sometimes paranoia is good.
592 did_trans_retry = true;
593
594 // We wait for the thread to transition to a more usable state.
595 for (int i = 1; i <= SuspendRetryCount; i++) {
596 // We used to do an "os::yield_all(i)" call here with the intention
597 // that yielding would increase on each retry. However, the parameter
598 // is ignored on Linux which means the yield didn't scale up. Waiting
599 // on the SR_lock below provides a much more predictable scale up for
600 // the delay. It also provides a simple/direct point to check for any
601 // safepoint requests from the VMThread
602
603 // temporarily drops SR_lock while doing wait with safepoint check
604 // (if we're a JavaThread - the WatcherThread can also call this)
605 // and increase delay with each retry
606 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
607
608 // check the actual thread state instead of what we saved above
609 if (thread_state() != _thread_in_native_trans) {
610 // the thread has transitioned to another thread state so
611 // try all the checks (except this one) one more time.
612 do_trans_retry = true;
613 break;
614 }
615 } // end retry loop
616
617
618 }
619 } while (do_trans_retry);
620
621 *bits |= 0x00000010;
622 return false;
623 }
624
625 // Wait for an external suspend request to complete (or be cancelled).
626 // Returns true if the thread is externally suspended and false otherwise.
627 //
628 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
629 uint32_t *bits) {
630 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
631 false /* !called_by_wait */, bits);
632
633 // local flag copies to minimize SR_lock hold time
634 bool is_suspended;
635 bool pending;
636 uint32_t reset_bits;
637
638 // set a marker so is_ext_suspend_completed() knows we are the caller
639 *bits |= 0x00010000;
640
641 // We use reset_bits to reinitialize the bits value at the top of
642 // each retry loop. This allows the caller to make use of any
643 // unused bits for their own marking purposes.
644 reset_bits = *bits;
645
646 {
647 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
648 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
649 delay, bits);
650 pending = is_external_suspend();
651 }
652 // must release SR_lock to allow suspension to complete
653
654 if (!pending) {
655 // A cancelled suspend request is the only false return from
656 // is_ext_suspend_completed() that keeps us from entering the
657 // retry loop.
658 *bits |= 0x00020000;
659 return false;
660 }
661
662 if (is_suspended) {
663 *bits |= 0x00040000;
664 return true;
665 }
666
667 for (int i = 1; i <= retries; i++) {
668 *bits = reset_bits; // reinit to only track last retry
669
670 // We used to do an "os::yield_all(i)" call here with the intention
671 // that yielding would increase on each retry. However, the parameter
672 // is ignored on Linux which means the yield didn't scale up. Waiting
673 // on the SR_lock below provides a much more predictable scale up for
674 // the delay. It also provides a simple/direct point to check for any
675 // safepoint requests from the VMThread
676
677 {
678 MutexLocker ml(SR_lock());
679 // wait with safepoint check (if we're a JavaThread - the WatcherThread
680 // can also call this) and increase delay with each retry
681 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
682
683 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
684 delay, bits);
685
686 // It is possible for the external suspend request to be cancelled
687 // (by a resume) before the actual suspend operation is completed.
688 // Refresh our local copy to see if we still need to wait.
689 pending = is_external_suspend();
690 }
691
692 if (!pending) {
693 // A cancelled suspend request is the only false return from
694 // is_ext_suspend_completed() that keeps us from staying in the
695 // retry loop.
696 *bits |= 0x00080000;
697 return false;
698 }
699
700 if (is_suspended) {
701 *bits |= 0x00100000;
702 return true;
703 }
704 } // end retry loop
705
706 // thread did not suspend after all our retries
707 *bits |= 0x00200000;
708 return false;
709 }
710
711 #ifndef PRODUCT
712 void JavaThread::record_jump(address target, address instr, const char* file,
713 int line) {
714
715 // This should not need to be atomic as the only way for simultaneous
716 // updates is via interrupts. Even then this should be rare or non-existent
717 // and we don't care that much anyway.
718
719 int index = _jmp_ring_index;
720 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
721 _jmp_ring[index]._target = (intptr_t) target;
722 _jmp_ring[index]._instruction = (intptr_t) instr;
723 _jmp_ring[index]._file = file;
724 _jmp_ring[index]._line = line;
725 }
726 #endif // PRODUCT
727
728 // Called by flat profiler
729 // Callers have already called wait_for_ext_suspend_completion
730 // The assertion for that is currently too complex to put here:
731 bool JavaThread::profile_last_Java_frame(frame* _fr) {
732 bool gotframe = false;
733 // self suspension saves needed state.
734 if (has_last_Java_frame() && _anchor.walkable()) {
735 *_fr = pd_last_frame();
736 gotframe = true;
737 }
738 return gotframe;
739 }
740
741 void Thread::interrupt(Thread* thread) {
742 debug_only(check_for_dangling_thread_pointer(thread);)
743 os::interrupt(thread);
744 }
745
746 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
747 debug_only(check_for_dangling_thread_pointer(thread);)
748 // Note: If clear_interrupted==false, this simply fetches and
749 // returns the value of the field osthread()->interrupted().
750 return os::is_interrupted(thread, clear_interrupted);
751 }
752
753
754 // GC Support
755 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
756 jint thread_parity = _oops_do_parity;
757 if (thread_parity != strong_roots_parity) {
758 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
759 if (res == thread_parity) {
760 return true;
761 } else {
762 guarantee(res == strong_roots_parity, "Or else what?");
763 return false;
764 }
765 }
766 return false;
767 }
768
769 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
770 active_handles()->oops_do(f);
771 // Do oop for ThreadShadow
772 f->do_oop((oop*)&_pending_exception);
773 handle_area()->oops_do(f);
774 }
775
776 void Thread::nmethods_do(CodeBlobClosure* cf) {
777 // no nmethods in a generic thread...
778 }
779
780 void Thread::metadata_handles_do(void f(Metadata*)) {
781 // Only walk the Handles in Thread.
782 if (metadata_handles() != NULL) {
783 for (int i = 0; i< metadata_handles()->length(); i++) {
784 f(metadata_handles()->at(i));
785 }
786 }
787 }
788
789 void Thread::print_on(outputStream* st) const {
790 // get_priority assumes osthread initialized
791 if (osthread() != NULL) {
792 int os_prio;
793 if (os::get_native_priority(this, &os_prio) == OS_OK) {
794 st->print("os_prio=%d ", os_prio);
795 }
796 st->print("tid=" INTPTR_FORMAT " ", this);
797 ext().print_on(st);
798 osthread()->print_on(st);
799 }
800 debug_only(if (WizardMode) print_owned_locks_on(st);)
801 }
802
803 // Thread::print_on_error() is called by fatal error handler. Don't use
804 // any lock or allocate memory.
805 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
806 if (is_VM_thread()) st->print("VMThread");
807 else if (is_Compiler_thread()) st->print("CompilerThread");
808 else if (is_Java_thread()) st->print("JavaThread");
809 else if (is_GC_task_thread()) st->print("GCTaskThread");
810 else if (is_Watcher_thread()) st->print("WatcherThread");
811 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
812 else st->print("Thread");
813
814 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
815 _stack_base - _stack_size, _stack_base);
816
817 if (osthread()) {
818 st->print(" [id=%d]", osthread()->thread_id());
819 }
820 }
821
822 #ifdef ASSERT
823 void Thread::print_owned_locks_on(outputStream* st) const {
824 Monitor *cur = _owned_locks;
825 if (cur == NULL) {
826 st->print(" (no locks) ");
827 } else {
828 st->print_cr(" Locks owned:");
829 while (cur) {
830 cur->print_on(st);
831 cur = cur->next();
832 }
833 }
834 }
835
836 static int ref_use_count = 0;
837
838 bool Thread::owns_locks_but_compiled_lock() const {
839 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
840 if (cur != Compile_lock) return true;
841 }
842 return false;
843 }
844
845
846 #endif
847
848 #ifndef PRODUCT
849
850 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
851 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
852 // no threads which allow_vm_block's are held
853 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
854 // Check if current thread is allowed to block at a safepoint
855 if (!(_allow_safepoint_count == 0)) {
856 fatal("Possible safepoint reached by thread that does not allow it");
857 }
858 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
859 fatal("LEAF method calling lock?");
860 }
861
862 #ifdef ASSERT
863 if (potential_vm_operation && is_Java_thread()
864 && !Universe::is_bootstrapping()) {
865 // Make sure we do not hold any locks that the VM thread also uses.
866 // This could potentially lead to deadlocks
867 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
868 // Threads_lock is special, since the safepoint synchronization will not start before this is
869 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
870 // since it is used to transfer control between JavaThreads and the VMThread
871 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
872 if ((cur->allow_vm_block() &&
873 cur != Threads_lock &&
874 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
875 cur != VMOperationRequest_lock &&
876 cur != VMOperationQueue_lock) ||
877 cur->rank() == Mutex::special) {
878 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
879 }
880 }
881 }
882
883 if (GCALotAtAllSafepoints) {
884 // We could enter a safepoint here and thus have a gc
885 InterfaceSupport::check_gc_alot();
886 }
887 #endif
888 }
889 #endif
890
891 bool Thread::is_in_stack(address adr) const {
892 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
893 address end = os::current_stack_pointer();
894 // Allow non Java threads to call this without stack_base
895 if (_stack_base == NULL) return true;
896 if (stack_base() >= adr && adr >= end) return true;
897
898 return false;
899 }
900
901
902 bool Thread::is_in_usable_stack(address adr) const {
903 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
904 size_t usable_stack_size = _stack_size - stack_guard_size;
905
906 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
907 }
908
909
910 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
911 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
912 // used for compilation in the future. If that change is made, the need for these methods
913 // should be revisited, and they should be removed if possible.
914
915 bool Thread::is_lock_owned(address adr) const {
916 return on_local_stack(adr);
917 }
918
919 bool Thread::set_as_starting_thread() {
920 // NOTE: this must be called inside the main thread.
921 return os::create_main_thread((JavaThread*)this);
922 }
923
924 static void initialize_class(Symbol* class_name, TRAPS) {
925 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
926 InstanceKlass::cast(klass)->initialize(CHECK);
927 }
928
929
930 // Creates the initial ThreadGroup
931 static Handle create_initial_thread_group(TRAPS) {
932 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
933 instanceKlassHandle klass (THREAD, k);
934
935 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
936 {
937 JavaValue result(T_VOID);
938 JavaCalls::call_special(&result,
939 system_instance,
940 klass,
941 vmSymbols::object_initializer_name(),
942 vmSymbols::void_method_signature(),
943 CHECK_NH);
944 }
945 Universe::set_system_thread_group(system_instance());
946
947 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
948 {
949 JavaValue result(T_VOID);
950 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
951 JavaCalls::call_special(&result,
952 main_instance,
953 klass,
954 vmSymbols::object_initializer_name(),
955 vmSymbols::threadgroup_string_void_signature(),
956 system_instance,
957 string,
958 CHECK_NH);
959 }
960 return main_instance;
961 }
962
963 // Creates the initial Thread
964 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
965 TRAPS) {
966 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
967 instanceKlassHandle klass (THREAD, k);
968 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
969
970 java_lang_Thread::set_thread(thread_oop(), thread);
971 java_lang_Thread::set_priority(thread_oop(), NormPriority);
972 thread->set_threadObj(thread_oop());
973
974 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
975
976 JavaValue result(T_VOID);
977 JavaCalls::call_special(&result, thread_oop,
978 klass,
979 vmSymbols::object_initializer_name(),
980 vmSymbols::threadgroup_string_void_signature(),
981 thread_group,
982 string,
983 CHECK_NULL);
984 return thread_oop();
985 }
986
987 static void call_initializeSystemClass(TRAPS) {
988 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
989 instanceKlassHandle klass (THREAD, k);
990
991 JavaValue result(T_VOID);
992 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
993 vmSymbols::void_method_signature(), CHECK);
994 }
995
996 char java_runtime_name[128] = "";
997 char java_runtime_version[128] = "";
998
999 // extract the JRE name from sun.misc.Version.java_runtime_name
1000 static const char* get_java_runtime_name(TRAPS) {
1001 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1002 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1003 fieldDescriptor fd;
1004 bool found = k != NULL &&
1005 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1006 vmSymbols::string_signature(), &fd);
1007 if (found) {
1008 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1009 if (name_oop == NULL) {
1010 return NULL;
1011 }
1012 const char* name = java_lang_String::as_utf8_string(name_oop,
1013 java_runtime_name,
1014 sizeof(java_runtime_name));
1015 return name;
1016 } else {
1017 return NULL;
1018 }
1019 }
1020
1021 // extract the JRE version from sun.misc.Version.java_runtime_version
1022 static const char* get_java_runtime_version(TRAPS) {
1023 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1024 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1025 fieldDescriptor fd;
1026 bool found = k != NULL &&
1027 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1028 vmSymbols::string_signature(), &fd);
1029 if (found) {
1030 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1031 if (name_oop == NULL) {
1032 return NULL;
1033 }
1034 const char* name = java_lang_String::as_utf8_string(name_oop,
1035 java_runtime_version,
1036 sizeof(java_runtime_version));
1037 return name;
1038 } else {
1039 return NULL;
1040 }
1041 }
1042
1043 // General purpose hook into Java code, run once when the VM is initialized.
1044 // The Java library method itself may be changed independently from the VM.
1045 static void call_postVMInitHook(TRAPS) {
1046 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1047 instanceKlassHandle klass (THREAD, k);
1048 if (klass.not_null()) {
1049 JavaValue result(T_VOID);
1050 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1051 vmSymbols::void_method_signature(),
1052 CHECK);
1053 }
1054 }
1055
1056 static void reset_vm_info_property(TRAPS) {
1057 // the vm info string
1058 ResourceMark rm(THREAD);
1059 const char *vm_info = VM_Version::vm_info_string();
1060
1061 // java.lang.System class
1062 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1063 instanceKlassHandle klass (THREAD, k);
1064
1065 // setProperty arguments
1066 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1067 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1068
1069 // return value
1070 JavaValue r(T_OBJECT);
1071
1072 // public static String setProperty(String key, String value);
1073 JavaCalls::call_static(&r,
1074 klass,
1075 vmSymbols::setProperty_name(),
1076 vmSymbols::string_string_string_signature(),
1077 key_str,
1078 value_str,
1079 CHECK);
1080 }
1081
1082
1083 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1084 bool daemon, TRAPS) {
1085 assert(thread_group.not_null(), "thread group should be specified");
1086 assert(threadObj() == NULL, "should only create Java thread object once");
1087
1088 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1089 instanceKlassHandle klass (THREAD, k);
1090 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1091
1092 java_lang_Thread::set_thread(thread_oop(), this);
1093 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1094 set_threadObj(thread_oop());
1095
1096 JavaValue result(T_VOID);
1097 if (thread_name != NULL) {
1098 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1099 // Thread gets assigned specified name and null target
1100 JavaCalls::call_special(&result,
1101 thread_oop,
1102 klass,
1103 vmSymbols::object_initializer_name(),
1104 vmSymbols::threadgroup_string_void_signature(),
1105 thread_group, // Argument 1
1106 name, // Argument 2
1107 THREAD);
1108 } else {
1109 // Thread gets assigned name "Thread-nnn" and null target
1110 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1111 JavaCalls::call_special(&result,
1112 thread_oop,
1113 klass,
1114 vmSymbols::object_initializer_name(),
1115 vmSymbols::threadgroup_runnable_void_signature(),
1116 thread_group, // Argument 1
1117 Handle(), // Argument 2
1118 THREAD);
1119 }
1120
1121
1122 if (daemon) {
1123 java_lang_Thread::set_daemon(thread_oop());
1124 }
1125
1126 if (HAS_PENDING_EXCEPTION) {
1127 return;
1128 }
1129
1130 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1131 Handle threadObj(THREAD, this->threadObj());
1132
1133 JavaCalls::call_special(&result,
1134 thread_group,
1135 group,
1136 vmSymbols::add_method_name(),
1137 vmSymbols::thread_void_signature(),
1138 threadObj, // Arg 1
1139 THREAD);
1140 }
1141
1142 // NamedThread -- non-JavaThread subclasses with multiple
1143 // uniquely named instances should derive from this.
1144 NamedThread::NamedThread() : Thread() {
1145 _name = NULL;
1146 _processed_thread = NULL;
1147 }
1148
1149 NamedThread::~NamedThread() {
1150 if (_name != NULL) {
1151 FREE_C_HEAP_ARRAY(char, _name);
1152 _name = NULL;
1153 }
1154 }
1155
1156 void NamedThread::set_name(const char* format, ...) {
1157 guarantee(_name == NULL, "Only get to set name once.");
1158 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1159 guarantee(_name != NULL, "alloc failure");
1160 va_list ap;
1161 va_start(ap, format);
1162 jio_vsnprintf(_name, max_name_len, format, ap);
1163 va_end(ap);
1164 }
1165
1166 void NamedThread::initialize_named_thread() {
1167 set_native_thread_name(name());
1168 }
1169
1170 void NamedThread::print_on(outputStream* st) const {
1171 st->print("\"%s\" ", name());
1172 Thread::print_on(st);
1173 st->cr();
1174 }
1175
1176
1177 // ======= WatcherThread ========
1178
1179 // The watcher thread exists to simulate timer interrupts. It should
1180 // be replaced by an abstraction over whatever native support for
1181 // timer interrupts exists on the platform.
1182
1183 WatcherThread* WatcherThread::_watcher_thread = NULL;
1184 bool WatcherThread::_startable = false;
1185 volatile bool WatcherThread::_should_terminate = false;
1186
1187 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1188 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1189 if (os::create_thread(this, os::watcher_thread)) {
1190 _watcher_thread = this;
1191
1192 // Set the watcher thread to the highest OS priority which should not be
1193 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1194 // is created. The only normal thread using this priority is the reference
1195 // handler thread, which runs for very short intervals only.
1196 // If the VMThread's priority is not lower than the WatcherThread profiling
1197 // will be inaccurate.
1198 os::set_priority(this, MaxPriority);
1199 if (!DisableStartThread) {
1200 os::start_thread(this);
1201 }
1202 }
1203 }
1204
1205 int WatcherThread::sleep() const {
1206 // The WatcherThread does not participate in the safepoint protocol
1207 // for the PeriodicTask_lock because it is not a JavaThread.
1208 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1209
1210 if (_should_terminate) {
1211 // check for termination before we do any housekeeping or wait
1212 return 0; // we did not sleep.
1213 }
1214
1215 // remaining will be zero if there are no tasks,
1216 // causing the WatcherThread to sleep until a task is
1217 // enrolled
1218 int remaining = PeriodicTask::time_to_wait();
1219 int time_slept = 0;
1220
1221 // we expect this to timeout - we only ever get unparked when
1222 // we should terminate or when a new task has been enrolled
1223 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1224
1225 jlong time_before_loop = os::javaTimeNanos();
1226
1227 while (true) {
1228 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1229 remaining);
1230 jlong now = os::javaTimeNanos();
1231
1232 if (remaining == 0) {
1233 // if we didn't have any tasks we could have waited for a long time
1234 // consider the time_slept zero and reset time_before_loop
1235 time_slept = 0;
1236 time_before_loop = now;
1237 } else {
1238 // need to recalculate since we might have new tasks in _tasks
1239 time_slept = (int) ((now - time_before_loop) / 1000000);
1240 }
1241
1242 // Change to task list or spurious wakeup of some kind
1243 if (timedout || _should_terminate) {
1244 break;
1245 }
1246
1247 remaining = PeriodicTask::time_to_wait();
1248 if (remaining == 0) {
1249 // Last task was just disenrolled so loop around and wait until
1250 // another task gets enrolled
1251 continue;
1252 }
1253
1254 remaining -= time_slept;
1255 if (remaining <= 0) {
1256 break;
1257 }
1258 }
1259
1260 return time_slept;
1261 }
1262
1263 void WatcherThread::run() {
1264 assert(this == watcher_thread(), "just checking");
1265
1266 this->record_stack_base_and_size();
1267 this->initialize_thread_local_storage();
1268 this->set_native_thread_name(this->name());
1269 this->set_active_handles(JNIHandleBlock::allocate_block());
1270 while (true) {
1271 assert(watcher_thread() == Thread::current(), "thread consistency check");
1272 assert(watcher_thread() == this, "thread consistency check");
1273
1274 // Calculate how long it'll be until the next PeriodicTask work
1275 // should be done, and sleep that amount of time.
1276 int time_waited = sleep();
1277
1278 if (is_error_reported()) {
1279 // A fatal error has happened, the error handler(VMError::report_and_die)
1280 // should abort JVM after creating an error log file. However in some
1281 // rare cases, the error handler itself might deadlock. Here we try to
1282 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1283 //
1284 // This code is in WatcherThread because WatcherThread wakes up
1285 // periodically so the fatal error handler doesn't need to do anything;
1286 // also because the WatcherThread is less likely to crash than other
1287 // threads.
1288
1289 for (;;) {
1290 if (!ShowMessageBoxOnError
1291 && (OnError == NULL || OnError[0] == '\0')
1292 && Arguments::abort_hook() == NULL) {
1293 os::sleep(this, 2 * 60 * 1000, false);
1294 fdStream err(defaultStream::output_fd());
1295 err.print_raw_cr("# [ timer expired, abort... ]");
1296 // skip atexit/vm_exit/vm_abort hooks
1297 os::die();
1298 }
1299
1300 // Wake up 5 seconds later, the fatal handler may reset OnError or
1301 // ShowMessageBoxOnError when it is ready to abort.
1302 os::sleep(this, 5 * 1000, false);
1303 }
1304 }
1305
1306 if (_should_terminate) {
1307 // check for termination before posting the next tick
1308 break;
1309 }
1310
1311 PeriodicTask::real_time_tick(time_waited);
1312 }
1313
1314 // Signal that it is terminated
1315 {
1316 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1317 _watcher_thread = NULL;
1318 Terminator_lock->notify();
1319 }
1320
1321 // Thread destructor usually does this..
1322 ThreadLocalStorage::set_thread(NULL);
1323 }
1324
1325 void WatcherThread::start() {
1326 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1327
1328 if (watcher_thread() == NULL && _startable) {
1329 _should_terminate = false;
1330 // Create the single instance of WatcherThread
1331 new WatcherThread();
1332 }
1333 }
1334
1335 void WatcherThread::make_startable() {
1336 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1337 _startable = true;
1338 }
1339
1340 void WatcherThread::stop() {
1341 {
1342 // Follow normal safepoint aware lock enter protocol since the
1343 // WatcherThread is stopped by another JavaThread.
1344 MutexLocker ml(PeriodicTask_lock);
1345 _should_terminate = true;
1346
1347 WatcherThread* watcher = watcher_thread();
1348 if (watcher != NULL) {
1349 // unpark the WatcherThread so it can see that it should terminate
1350 watcher->unpark();
1351 }
1352 }
1353
1354 MutexLocker mu(Terminator_lock);
1355
1356 while (watcher_thread() != NULL) {
1357 // This wait should make safepoint checks, wait without a timeout,
1358 // and wait as a suspend-equivalent condition.
1359 //
1360 // Note: If the FlatProfiler is running, then this thread is waiting
1361 // for the WatcherThread to terminate and the WatcherThread, via the
1362 // FlatProfiler task, is waiting for the external suspend request on
1363 // this thread to complete. wait_for_ext_suspend_completion() will
1364 // eventually timeout, but that takes time. Making this wait a
1365 // suspend-equivalent condition solves that timeout problem.
1366 //
1367 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1368 Mutex::_as_suspend_equivalent_flag);
1369 }
1370 }
1371
1372 void WatcherThread::unpark() {
1373 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1374 PeriodicTask_lock->notify();
1375 }
1376
1377 void WatcherThread::print_on(outputStream* st) const {
1378 st->print("\"%s\" ", name());
1379 Thread::print_on(st);
1380 st->cr();
1381 }
1382
1383 // ======= JavaThread ========
1384
1385 // A JavaThread is a normal Java thread
1386
1387 void JavaThread::initialize() {
1388 // Initialize fields
1389
1390 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1391 set_claimed_par_id(UINT_MAX);
1392
1393 set_saved_exception_pc(NULL);
1394 set_threadObj(NULL);
1395 _anchor.clear();
1396 set_entry_point(NULL);
1397 set_jni_functions(jni_functions());
1398 set_callee_target(NULL);
1399 set_vm_result(NULL);
1400 set_vm_result_2(NULL);
1401 set_vframe_array_head(NULL);
1402 set_vframe_array_last(NULL);
1403 set_deferred_locals(NULL);
1404 set_deopt_mark(NULL);
1405 set_deopt_nmethod(NULL);
1406 clear_must_deopt_id();
1407 set_monitor_chunks(NULL);
1408 set_next(NULL);
1409 set_thread_state(_thread_new);
1410 _terminated = _not_terminated;
1411 _privileged_stack_top = NULL;
1412 _array_for_gc = NULL;
1413 _suspend_equivalent = false;
1414 _in_deopt_handler = 0;
1415 _doing_unsafe_access = false;
1416 _stack_guard_state = stack_guard_unused;
1417 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1418 _exception_pc = 0;
1419 _exception_handler_pc = 0;
1420 _is_method_handle_return = 0;
1421 _jvmti_thread_state= NULL;
1422 _should_post_on_exceptions_flag = JNI_FALSE;
1423 _jvmti_get_loaded_classes_closure = NULL;
1424 _interp_only_mode = 0;
1425 _special_runtime_exit_condition = _no_async_condition;
1426 _pending_async_exception = NULL;
1427 _thread_stat = NULL;
1428 _thread_stat = new ThreadStatistics();
1429 _blocked_on_compilation = false;
1430 _jni_active_critical = 0;
1431 _pending_jni_exception_check_fn = NULL;
1432 _do_not_unlock_if_synchronized = false;
1433 _cached_monitor_info = NULL;
1434 _parker = Parker::Allocate(this);
1435
1436 #ifndef PRODUCT
1437 _jmp_ring_index = 0;
1438 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1439 record_jump(NULL, NULL, NULL, 0);
1440 }
1441 #endif // PRODUCT
1442
1443 set_thread_profiler(NULL);
1444 if (FlatProfiler::is_active()) {
1445 // This is where we would decide to either give each thread it's own profiler
1446 // or use one global one from FlatProfiler,
1447 // or up to some count of the number of profiled threads, etc.
1448 ThreadProfiler* pp = new ThreadProfiler();
1449 pp->engage();
1450 set_thread_profiler(pp);
1451 }
1452
1453 // Setup safepoint state info for this thread
1454 ThreadSafepointState::create(this);
1455
1456 debug_only(_java_call_counter = 0);
1457
1458 // JVMTI PopFrame support
1459 _popframe_condition = popframe_inactive;
1460 _popframe_preserved_args = NULL;
1461 _popframe_preserved_args_size = 0;
1462 _frames_to_pop_failed_realloc = 0;
1463
1464 pd_initialize();
1465 }
1466
1467 #if INCLUDE_ALL_GCS
1468 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1469 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1470 #endif // INCLUDE_ALL_GCS
1471
1472 JavaThread::JavaThread(bool is_attaching_via_jni) :
1473 Thread()
1474 #if INCLUDE_ALL_GCS
1475 , _satb_mark_queue(&_satb_mark_queue_set),
1476 _dirty_card_queue(&_dirty_card_queue_set)
1477 #endif // INCLUDE_ALL_GCS
1478 {
1479 initialize();
1480 if (is_attaching_via_jni) {
1481 _jni_attach_state = _attaching_via_jni;
1482 } else {
1483 _jni_attach_state = _not_attaching_via_jni;
1484 }
1485 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1486 }
1487
1488 bool JavaThread::reguard_stack(address cur_sp) {
1489 if (_stack_guard_state != stack_guard_yellow_disabled) {
1490 return true; // Stack already guarded or guard pages not needed.
1491 }
1492
1493 if (register_stack_overflow()) {
1494 // For those architectures which have separate register and
1495 // memory stacks, we must check the register stack to see if
1496 // it has overflowed.
1497 return false;
1498 }
1499
1500 // Java code never executes within the yellow zone: the latter is only
1501 // there to provoke an exception during stack banging. If java code
1502 // is executing there, either StackShadowPages should be larger, or
1503 // some exception code in c1, c2 or the interpreter isn't unwinding
1504 // when it should.
1505 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1506
1507 enable_stack_yellow_zone();
1508 return true;
1509 }
1510
1511 bool JavaThread::reguard_stack(void) {
1512 return reguard_stack(os::current_stack_pointer());
1513 }
1514
1515
1516 void JavaThread::block_if_vm_exited() {
1517 if (_terminated == _vm_exited) {
1518 // _vm_exited is set at safepoint, and Threads_lock is never released
1519 // we will block here forever
1520 Threads_lock->lock_without_safepoint_check();
1521 ShouldNotReachHere();
1522 }
1523 }
1524
1525
1526 // Remove this ifdef when C1 is ported to the compiler interface.
1527 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1528 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1529
1530 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1531 Thread()
1532 #if INCLUDE_ALL_GCS
1533 , _satb_mark_queue(&_satb_mark_queue_set),
1534 _dirty_card_queue(&_dirty_card_queue_set)
1535 #endif // INCLUDE_ALL_GCS
1536 {
1537 initialize();
1538 _jni_attach_state = _not_attaching_via_jni;
1539 set_entry_point(entry_point);
1540 // Create the native thread itself.
1541 // %note runtime_23
1542 os::ThreadType thr_type = os::java_thread;
1543 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1544 os::java_thread;
1545 os::create_thread(this, thr_type, stack_sz);
1546 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1547 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1548 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1549 // the exception consists of creating the exception object & initializing it, initialization
1550 // will leave the VM via a JavaCall and then all locks must be unlocked).
1551 //
1552 // The thread is still suspended when we reach here. Thread must be explicit started
1553 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1554 // by calling Threads:add. The reason why this is not done here, is because the thread
1555 // object must be fully initialized (take a look at JVM_Start)
1556 }
1557
1558 JavaThread::~JavaThread() {
1559
1560 // JSR166 -- return the parker to the free list
1561 Parker::Release(_parker);
1562 _parker = NULL;
1563
1564 // Free any remaining previous UnrollBlock
1565 vframeArray* old_array = vframe_array_last();
1566
1567 if (old_array != NULL) {
1568 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1569 old_array->set_unroll_block(NULL);
1570 delete old_info;
1571 delete old_array;
1572 }
1573
1574 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1575 if (deferred != NULL) {
1576 // This can only happen if thread is destroyed before deoptimization occurs.
1577 assert(deferred->length() != 0, "empty array!");
1578 do {
1579 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1580 deferred->remove_at(0);
1581 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1582 delete dlv;
1583 } while (deferred->length() != 0);
1584 delete deferred;
1585 }
1586
1587 // All Java related clean up happens in exit
1588 ThreadSafepointState::destroy(this);
1589 if (_thread_profiler != NULL) delete _thread_profiler;
1590 if (_thread_stat != NULL) delete _thread_stat;
1591 }
1592
1593
1594 // The first routine called by a new Java thread
1595 void JavaThread::run() {
1596 // initialize thread-local alloc buffer related fields
1597 this->initialize_tlab();
1598
1599 // used to test validity of stack trace backs
1600 this->record_base_of_stack_pointer();
1601
1602 // Record real stack base and size.
1603 this->record_stack_base_and_size();
1604
1605 // Initialize thread local storage; set before calling MutexLocker
1606 this->initialize_thread_local_storage();
1607
1608 this->create_stack_guard_pages();
1609
1610 this->cache_global_variables();
1611
1612 // Thread is now sufficient initialized to be handled by the safepoint code as being
1613 // in the VM. Change thread state from _thread_new to _thread_in_vm
1614 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1615
1616 assert(JavaThread::current() == this, "sanity check");
1617 assert(!Thread::current()->owns_locks(), "sanity check");
1618
1619 DTRACE_THREAD_PROBE(start, this);
1620
1621 // This operation might block. We call that after all safepoint checks for a new thread has
1622 // been completed.
1623 this->set_active_handles(JNIHandleBlock::allocate_block());
1624
1625 if (JvmtiExport::should_post_thread_life()) {
1626 JvmtiExport::post_thread_start(this);
1627 }
1628
1629 EventThreadStart event;
1630 if (event.should_commit()) {
1631 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1632 event.commit();
1633 }
1634
1635 // We call another function to do the rest so we are sure that the stack addresses used
1636 // from there will be lower than the stack base just computed
1637 thread_main_inner();
1638
1639 // Note, thread is no longer valid at this point!
1640 }
1641
1642
1643 void JavaThread::thread_main_inner() {
1644 assert(JavaThread::current() == this, "sanity check");
1645 assert(this->threadObj() != NULL, "just checking");
1646
1647 // Execute thread entry point unless this thread has a pending exception
1648 // or has been stopped before starting.
1649 // Note: Due to JVM_StopThread we can have pending exceptions already!
1650 if (!this->has_pending_exception() &&
1651 !java_lang_Thread::is_stillborn(this->threadObj())) {
1652 {
1653 ResourceMark rm(this);
1654 this->set_native_thread_name(this->get_thread_name());
1655 }
1656 HandleMark hm(this);
1657 this->entry_point()(this, this);
1658 }
1659
1660 DTRACE_THREAD_PROBE(stop, this);
1661
1662 this->exit(false);
1663 delete this;
1664 }
1665
1666
1667 static void ensure_join(JavaThread* thread) {
1668 // We do not need to grap the Threads_lock, since we are operating on ourself.
1669 Handle threadObj(thread, thread->threadObj());
1670 assert(threadObj.not_null(), "java thread object must exist");
1671 ObjectLocker lock(threadObj, thread);
1672 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1673 thread->clear_pending_exception();
1674 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1675 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1676 // Clear the native thread instance - this makes isAlive return false and allows the join()
1677 // to complete once we've done the notify_all below
1678 java_lang_Thread::set_thread(threadObj(), NULL);
1679 lock.notify_all(thread);
1680 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1681 thread->clear_pending_exception();
1682 }
1683
1684
1685 // For any new cleanup additions, please check to see if they need to be applied to
1686 // cleanup_failed_attach_current_thread as well.
1687 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1688 assert(this == JavaThread::current(), "thread consistency check");
1689
1690 HandleMark hm(this);
1691 Handle uncaught_exception(this, this->pending_exception());
1692 this->clear_pending_exception();
1693 Handle threadObj(this, this->threadObj());
1694 assert(threadObj.not_null(), "Java thread object should be created");
1695
1696 if (get_thread_profiler() != NULL) {
1697 get_thread_profiler()->disengage();
1698 ResourceMark rm;
1699 get_thread_profiler()->print(get_thread_name());
1700 }
1701
1702
1703 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1704 {
1705 EXCEPTION_MARK;
1706
1707 CLEAR_PENDING_EXCEPTION;
1708 }
1709 if (!destroy_vm) {
1710 if (uncaught_exception.not_null()) {
1711 EXCEPTION_MARK;
1712 // Call method Thread.dispatchUncaughtException().
1713 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1714 JavaValue result(T_VOID);
1715 JavaCalls::call_virtual(&result,
1716 threadObj, thread_klass,
1717 vmSymbols::dispatchUncaughtException_name(),
1718 vmSymbols::throwable_void_signature(),
1719 uncaught_exception,
1720 THREAD);
1721 if (HAS_PENDING_EXCEPTION) {
1722 ResourceMark rm(this);
1723 jio_fprintf(defaultStream::error_stream(),
1724 "\nException: %s thrown from the UncaughtExceptionHandler"
1725 " in thread \"%s\"\n",
1726 pending_exception()->klass()->external_name(),
1727 get_thread_name());
1728 CLEAR_PENDING_EXCEPTION;
1729 }
1730 }
1731
1732 // Called before the java thread exit since we want to read info
1733 // from java_lang_Thread object
1734 EventThreadEnd event;
1735 if (event.should_commit()) {
1736 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1737 event.commit();
1738 }
1739
1740 // Call after last event on thread
1741 EVENT_THREAD_EXIT(this);
1742
1743 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1744 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1745 // is deprecated anyhow.
1746 if (!is_Compiler_thread()) {
1747 int count = 3;
1748 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1749 EXCEPTION_MARK;
1750 JavaValue result(T_VOID);
1751 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1752 JavaCalls::call_virtual(&result,
1753 threadObj, thread_klass,
1754 vmSymbols::exit_method_name(),
1755 vmSymbols::void_method_signature(),
1756 THREAD);
1757 CLEAR_PENDING_EXCEPTION;
1758 }
1759 }
1760 // notify JVMTI
1761 if (JvmtiExport::should_post_thread_life()) {
1762 JvmtiExport::post_thread_end(this);
1763 }
1764
1765 // We have notified the agents that we are exiting, before we go on,
1766 // we must check for a pending external suspend request and honor it
1767 // in order to not surprise the thread that made the suspend request.
1768 while (true) {
1769 {
1770 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1771 if (!is_external_suspend()) {
1772 set_terminated(_thread_exiting);
1773 ThreadService::current_thread_exiting(this);
1774 break;
1775 }
1776 // Implied else:
1777 // Things get a little tricky here. We have a pending external
1778 // suspend request, but we are holding the SR_lock so we
1779 // can't just self-suspend. So we temporarily drop the lock
1780 // and then self-suspend.
1781 }
1782
1783 ThreadBlockInVM tbivm(this);
1784 java_suspend_self();
1785
1786 // We're done with this suspend request, but we have to loop around
1787 // and check again. Eventually we will get SR_lock without a pending
1788 // external suspend request and will be able to mark ourselves as
1789 // exiting.
1790 }
1791 // no more external suspends are allowed at this point
1792 } else {
1793 // before_exit() has already posted JVMTI THREAD_END events
1794 }
1795
1796 // Notify waiters on thread object. This has to be done after exit() is called
1797 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1798 // group should have the destroyed bit set before waiters are notified).
1799 ensure_join(this);
1800 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1801
1802 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1803 // held by this thread must be released. A detach operation must only
1804 // get here if there are no Java frames on the stack. Therefore, any
1805 // owned monitors at this point MUST be JNI-acquired monitors which are
1806 // pre-inflated and in the monitor cache.
1807 //
1808 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1809 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1810 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1811 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1812 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1813 }
1814
1815 // These things needs to be done while we are still a Java Thread. Make sure that thread
1816 // is in a consistent state, in case GC happens
1817 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1818
1819 if (active_handles() != NULL) {
1820 JNIHandleBlock* block = active_handles();
1821 set_active_handles(NULL);
1822 JNIHandleBlock::release_block(block);
1823 }
1824
1825 if (free_handle_block() != NULL) {
1826 JNIHandleBlock* block = free_handle_block();
1827 set_free_handle_block(NULL);
1828 JNIHandleBlock::release_block(block);
1829 }
1830
1831 // These have to be removed while this is still a valid thread.
1832 remove_stack_guard_pages();
1833
1834 if (UseTLAB) {
1835 tlab().make_parsable(true); // retire TLAB
1836 }
1837
1838 if (JvmtiEnv::environments_might_exist()) {
1839 JvmtiExport::cleanup_thread(this);
1840 }
1841
1842 // We must flush any deferred card marks before removing a thread from
1843 // the list of active threads.
1844 Universe::heap()->flush_deferred_store_barrier(this);
1845 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1846
1847 #if INCLUDE_ALL_GCS
1848 // We must flush the G1-related buffers before removing a thread
1849 // from the list of active threads. We must do this after any deferred
1850 // card marks have been flushed (above) so that any entries that are
1851 // added to the thread's dirty card queue as a result are not lost.
1852 if (UseG1GC) {
1853 flush_barrier_queues();
1854 }
1855 #endif // INCLUDE_ALL_GCS
1856
1857 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1858 Threads::remove(this);
1859 }
1860
1861 #if INCLUDE_ALL_GCS
1862 // Flush G1-related queues.
1863 void JavaThread::flush_barrier_queues() {
1864 satb_mark_queue().flush();
1865 dirty_card_queue().flush();
1866 }
1867
1868 void JavaThread::initialize_queues() {
1869 assert(!SafepointSynchronize::is_at_safepoint(),
1870 "we should not be at a safepoint");
1871
1872 ObjPtrQueue& satb_queue = satb_mark_queue();
1873 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1874 // The SATB queue should have been constructed with its active
1875 // field set to false.
1876 assert(!satb_queue.is_active(), "SATB queue should not be active");
1877 assert(satb_queue.is_empty(), "SATB queue should be empty");
1878 // If we are creating the thread during a marking cycle, we should
1879 // set the active field of the SATB queue to true.
1880 if (satb_queue_set.is_active()) {
1881 satb_queue.set_active(true);
1882 }
1883
1884 DirtyCardQueue& dirty_queue = dirty_card_queue();
1885 // The dirty card queue should have been constructed with its
1886 // active field set to true.
1887 assert(dirty_queue.is_active(), "dirty card queue should be active");
1888 }
1889 #endif // INCLUDE_ALL_GCS
1890
1891 void JavaThread::cleanup_failed_attach_current_thread() {
1892 if (get_thread_profiler() != NULL) {
1893 get_thread_profiler()->disengage();
1894 ResourceMark rm;
1895 get_thread_profiler()->print(get_thread_name());
1896 }
1897
1898 if (active_handles() != NULL) {
1899 JNIHandleBlock* block = active_handles();
1900 set_active_handles(NULL);
1901 JNIHandleBlock::release_block(block);
1902 }
1903
1904 if (free_handle_block() != NULL) {
1905 JNIHandleBlock* block = free_handle_block();
1906 set_free_handle_block(NULL);
1907 JNIHandleBlock::release_block(block);
1908 }
1909
1910 // These have to be removed while this is still a valid thread.
1911 remove_stack_guard_pages();
1912
1913 if (UseTLAB) {
1914 tlab().make_parsable(true); // retire TLAB, if any
1915 }
1916
1917 #if INCLUDE_ALL_GCS
1918 if (UseG1GC) {
1919 flush_barrier_queues();
1920 }
1921 #endif // INCLUDE_ALL_GCS
1922
1923 Threads::remove(this);
1924 delete this;
1925 }
1926
1927
1928
1929
1930 JavaThread* JavaThread::active() {
1931 Thread* thread = ThreadLocalStorage::thread();
1932 assert(thread != NULL, "just checking");
1933 if (thread->is_Java_thread()) {
1934 return (JavaThread*) thread;
1935 } else {
1936 assert(thread->is_VM_thread(), "this must be a vm thread");
1937 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1938 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1939 assert(ret->is_Java_thread(), "must be a Java thread");
1940 return ret;
1941 }
1942 }
1943
1944 bool JavaThread::is_lock_owned(address adr) const {
1945 if (Thread::is_lock_owned(adr)) return true;
1946
1947 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1948 if (chunk->contains(adr)) return true;
1949 }
1950
1951 return false;
1952 }
1953
1954
1955 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1956 chunk->set_next(monitor_chunks());
1957 set_monitor_chunks(chunk);
1958 }
1959
1960 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1961 guarantee(monitor_chunks() != NULL, "must be non empty");
1962 if (monitor_chunks() == chunk) {
1963 set_monitor_chunks(chunk->next());
1964 } else {
1965 MonitorChunk* prev = monitor_chunks();
1966 while (prev->next() != chunk) prev = prev->next();
1967 prev->set_next(chunk->next());
1968 }
1969 }
1970
1971 // JVM support.
1972
1973 // Note: this function shouldn't block if it's called in
1974 // _thread_in_native_trans state (such as from
1975 // check_special_condition_for_native_trans()).
1976 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1977
1978 if (has_last_Java_frame() && has_async_condition()) {
1979 // If we are at a polling page safepoint (not a poll return)
1980 // then we must defer async exception because live registers
1981 // will be clobbered by the exception path. Poll return is
1982 // ok because the call we a returning from already collides
1983 // with exception handling registers and so there is no issue.
1984 // (The exception handling path kills call result registers but
1985 // this is ok since the exception kills the result anyway).
1986
1987 if (is_at_poll_safepoint()) {
1988 // if the code we are returning to has deoptimized we must defer
1989 // the exception otherwise live registers get clobbered on the
1990 // exception path before deoptimization is able to retrieve them.
1991 //
1992 RegisterMap map(this, false);
1993 frame caller_fr = last_frame().sender(&map);
1994 assert(caller_fr.is_compiled_frame(), "what?");
1995 if (caller_fr.is_deoptimized_frame()) {
1996 if (TraceExceptions) {
1997 ResourceMark rm;
1998 tty->print_cr("deferred async exception at compiled safepoint");
1999 }
2000 return;
2001 }
2002 }
2003 }
2004
2005 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2006 if (condition == _no_async_condition) {
2007 // Conditions have changed since has_special_runtime_exit_condition()
2008 // was called:
2009 // - if we were here only because of an external suspend request,
2010 // then that was taken care of above (or cancelled) so we are done
2011 // - if we were here because of another async request, then it has
2012 // been cleared between the has_special_runtime_exit_condition()
2013 // and now so again we are done
2014 return;
2015 }
2016
2017 // Check for pending async. exception
2018 if (_pending_async_exception != NULL) {
2019 // Only overwrite an already pending exception, if it is not a threadDeath.
2020 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2021
2022 // We cannot call Exceptions::_throw(...) here because we cannot block
2023 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2024
2025 if (TraceExceptions) {
2026 ResourceMark rm;
2027 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2028 if (has_last_Java_frame()) {
2029 frame f = last_frame();
2030 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2031 }
2032 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2033 }
2034 _pending_async_exception = NULL;
2035 clear_has_async_exception();
2036 }
2037 }
2038
2039 if (check_unsafe_error &&
2040 condition == _async_unsafe_access_error && !has_pending_exception()) {
2041 condition = _no_async_condition; // done
2042 switch (thread_state()) {
2043 case _thread_in_vm: {
2044 JavaThread* THREAD = this;
2045 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2046 }
2047 case _thread_in_native: {
2048 ThreadInVMfromNative tiv(this);
2049 JavaThread* THREAD = this;
2050 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2051 }
2052 case _thread_in_Java: {
2053 ThreadInVMfromJava tiv(this);
2054 JavaThread* THREAD = this;
2055 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2056 }
2057 default:
2058 ShouldNotReachHere();
2059 }
2060 }
2061
2062 assert(condition == _no_async_condition || has_pending_exception() ||
2063 (!check_unsafe_error && condition == _async_unsafe_access_error),
2064 "must have handled the async condition, if no exception");
2065 }
2066
2067 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2068 //
2069 // Check for pending external suspend. Internal suspend requests do
2070 // not use handle_special_runtime_exit_condition().
2071 // If JNIEnv proxies are allowed, don't self-suspend if the target
2072 // thread is not the current thread. In older versions of jdbx, jdbx
2073 // threads could call into the VM with another thread's JNIEnv so we
2074 // can be here operating on behalf of a suspended thread (4432884).
2075 bool do_self_suspend = is_external_suspend_with_lock();
2076 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2077 //
2078 // Because thread is external suspended the safepoint code will count
2079 // thread as at a safepoint. This can be odd because we can be here
2080 // as _thread_in_Java which would normally transition to _thread_blocked
2081 // at a safepoint. We would like to mark the thread as _thread_blocked
2082 // before calling java_suspend_self like all other callers of it but
2083 // we must then observe proper safepoint protocol. (We can't leave
2084 // _thread_blocked with a safepoint in progress). However we can be
2085 // here as _thread_in_native_trans so we can't use a normal transition
2086 // constructor/destructor pair because they assert on that type of
2087 // transition. We could do something like:
2088 //
2089 // JavaThreadState state = thread_state();
2090 // set_thread_state(_thread_in_vm);
2091 // {
2092 // ThreadBlockInVM tbivm(this);
2093 // java_suspend_self()
2094 // }
2095 // set_thread_state(_thread_in_vm_trans);
2096 // if (safepoint) block;
2097 // set_thread_state(state);
2098 //
2099 // but that is pretty messy. Instead we just go with the way the
2100 // code has worked before and note that this is the only path to
2101 // java_suspend_self that doesn't put the thread in _thread_blocked
2102 // mode.
2103
2104 frame_anchor()->make_walkable(this);
2105 java_suspend_self();
2106
2107 // We might be here for reasons in addition to the self-suspend request
2108 // so check for other async requests.
2109 }
2110
2111 if (check_asyncs) {
2112 check_and_handle_async_exceptions();
2113 }
2114 }
2115
2116 void JavaThread::send_thread_stop(oop java_throwable) {
2117 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2118 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2119 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2120
2121 // Do not throw asynchronous exceptions against the compiler thread
2122 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2123 if (is_Compiler_thread()) return;
2124
2125 {
2126 // Actually throw the Throwable against the target Thread - however
2127 // only if there is no thread death exception installed already.
2128 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2129 // If the topmost frame is a runtime stub, then we are calling into
2130 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2131 // must deoptimize the caller before continuing, as the compiled exception handler table
2132 // may not be valid
2133 if (has_last_Java_frame()) {
2134 frame f = last_frame();
2135 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2136 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2137 RegisterMap reg_map(this, UseBiasedLocking);
2138 frame compiled_frame = f.sender(®_map);
2139 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2140 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2141 }
2142 }
2143 }
2144
2145 // Set async. pending exception in thread.
2146 set_pending_async_exception(java_throwable);
2147
2148 if (TraceExceptions) {
2149 ResourceMark rm;
2150 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2151 }
2152 // for AbortVMOnException flag
2153 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2154 }
2155 }
2156
2157
2158 // Interrupt thread so it will wake up from a potential wait()
2159 Thread::interrupt(this);
2160 }
2161
2162 // External suspension mechanism.
2163 //
2164 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2165 // to any VM_locks and it is at a transition
2166 // Self-suspension will happen on the transition out of the vm.
2167 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2168 //
2169 // Guarantees on return:
2170 // + Target thread will not execute any new bytecode (that's why we need to
2171 // force a safepoint)
2172 // + Target thread will not enter any new monitors
2173 //
2174 void JavaThread::java_suspend() {
2175 { MutexLocker mu(Threads_lock);
2176 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2177 return;
2178 }
2179 }
2180
2181 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2182 if (!is_external_suspend()) {
2183 // a racing resume has cancelled us; bail out now
2184 return;
2185 }
2186
2187 // suspend is done
2188 uint32_t debug_bits = 0;
2189 // Warning: is_ext_suspend_completed() may temporarily drop the
2190 // SR_lock to allow the thread to reach a stable thread state if
2191 // it is currently in a transient thread state.
2192 if (is_ext_suspend_completed(false /* !called_by_wait */,
2193 SuspendRetryDelay, &debug_bits)) {
2194 return;
2195 }
2196 }
2197
2198 VM_ForceSafepoint vm_suspend;
2199 VMThread::execute(&vm_suspend);
2200 }
2201
2202 // Part II of external suspension.
2203 // A JavaThread self suspends when it detects a pending external suspend
2204 // request. This is usually on transitions. It is also done in places
2205 // where continuing to the next transition would surprise the caller,
2206 // e.g., monitor entry.
2207 //
2208 // Returns the number of times that the thread self-suspended.
2209 //
2210 // Note: DO NOT call java_suspend_self() when you just want to block current
2211 // thread. java_suspend_self() is the second stage of cooperative
2212 // suspension for external suspend requests and should only be used
2213 // to complete an external suspend request.
2214 //
2215 int JavaThread::java_suspend_self() {
2216 int ret = 0;
2217
2218 // we are in the process of exiting so don't suspend
2219 if (is_exiting()) {
2220 clear_external_suspend();
2221 return ret;
2222 }
2223
2224 assert(_anchor.walkable() ||
2225 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2226 "must have walkable stack");
2227
2228 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2229
2230 assert(!this->is_ext_suspended(),
2231 "a thread trying to self-suspend should not already be suspended");
2232
2233 if (this->is_suspend_equivalent()) {
2234 // If we are self-suspending as a result of the lifting of a
2235 // suspend equivalent condition, then the suspend_equivalent
2236 // flag is not cleared until we set the ext_suspended flag so
2237 // that wait_for_ext_suspend_completion() returns consistent
2238 // results.
2239 this->clear_suspend_equivalent();
2240 }
2241
2242 // A racing resume may have cancelled us before we grabbed SR_lock
2243 // above. Or another external suspend request could be waiting for us
2244 // by the time we return from SR_lock()->wait(). The thread
2245 // that requested the suspension may already be trying to walk our
2246 // stack and if we return now, we can change the stack out from under
2247 // it. This would be a "bad thing (TM)" and cause the stack walker
2248 // to crash. We stay self-suspended until there are no more pending
2249 // external suspend requests.
2250 while (is_external_suspend()) {
2251 ret++;
2252 this->set_ext_suspended();
2253
2254 // _ext_suspended flag is cleared by java_resume()
2255 while (is_ext_suspended()) {
2256 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2257 }
2258 }
2259
2260 return ret;
2261 }
2262
2263 #ifdef ASSERT
2264 // verify the JavaThread has not yet been published in the Threads::list, and
2265 // hence doesn't need protection from concurrent access at this stage
2266 void JavaThread::verify_not_published() {
2267 if (!Threads_lock->owned_by_self()) {
2268 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2269 assert(!Threads::includes(this),
2270 "java thread shouldn't have been published yet!");
2271 } else {
2272 assert(!Threads::includes(this),
2273 "java thread shouldn't have been published yet!");
2274 }
2275 }
2276 #endif
2277
2278 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2279 // progress or when _suspend_flags is non-zero.
2280 // Current thread needs to self-suspend if there is a suspend request and/or
2281 // block if a safepoint is in progress.
2282 // Async exception ISN'T checked.
2283 // Note only the ThreadInVMfromNative transition can call this function
2284 // directly and when thread state is _thread_in_native_trans
2285 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2286 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2287
2288 JavaThread *curJT = JavaThread::current();
2289 bool do_self_suspend = thread->is_external_suspend();
2290
2291 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2292
2293 // If JNIEnv proxies are allowed, don't self-suspend if the target
2294 // thread is not the current thread. In older versions of jdbx, jdbx
2295 // threads could call into the VM with another thread's JNIEnv so we
2296 // can be here operating on behalf of a suspended thread (4432884).
2297 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2298 JavaThreadState state = thread->thread_state();
2299
2300 // We mark this thread_blocked state as a suspend-equivalent so
2301 // that a caller to is_ext_suspend_completed() won't be confused.
2302 // The suspend-equivalent state is cleared by java_suspend_self().
2303 thread->set_suspend_equivalent();
2304
2305 // If the safepoint code sees the _thread_in_native_trans state, it will
2306 // wait until the thread changes to other thread state. There is no
2307 // guarantee on how soon we can obtain the SR_lock and complete the
2308 // self-suspend request. It would be a bad idea to let safepoint wait for
2309 // too long. Temporarily change the state to _thread_blocked to
2310 // let the VM thread know that this thread is ready for GC. The problem
2311 // of changing thread state is that safepoint could happen just after
2312 // java_suspend_self() returns after being resumed, and VM thread will
2313 // see the _thread_blocked state. We must check for safepoint
2314 // after restoring the state and make sure we won't leave while a safepoint
2315 // is in progress.
2316 thread->set_thread_state(_thread_blocked);
2317 thread->java_suspend_self();
2318 thread->set_thread_state(state);
2319 // Make sure new state is seen by VM thread
2320 if (os::is_MP()) {
2321 if (UseMembar) {
2322 // Force a fence between the write above and read below
2323 OrderAccess::fence();
2324 } else {
2325 // Must use this rather than serialization page in particular on Windows
2326 InterfaceSupport::serialize_memory(thread);
2327 }
2328 }
2329 }
2330
2331 if (SafepointSynchronize::do_call_back()) {
2332 // If we are safepointing, then block the caller which may not be
2333 // the same as the target thread (see above).
2334 SafepointSynchronize::block(curJT);
2335 }
2336
2337 if (thread->is_deopt_suspend()) {
2338 thread->clear_deopt_suspend();
2339 RegisterMap map(thread, false);
2340 frame f = thread->last_frame();
2341 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2342 f = f.sender(&map);
2343 }
2344 if (f.id() == thread->must_deopt_id()) {
2345 thread->clear_must_deopt_id();
2346 f.deoptimize(thread);
2347 } else {
2348 fatal("missed deoptimization!");
2349 }
2350 }
2351 }
2352
2353 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2354 // progress or when _suspend_flags is non-zero.
2355 // Current thread needs to self-suspend if there is a suspend request and/or
2356 // block if a safepoint is in progress.
2357 // Also check for pending async exception (not including unsafe access error).
2358 // Note only the native==>VM/Java barriers can call this function and when
2359 // thread state is _thread_in_native_trans.
2360 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2361 check_safepoint_and_suspend_for_native_trans(thread);
2362
2363 if (thread->has_async_exception()) {
2364 // We are in _thread_in_native_trans state, don't handle unsafe
2365 // access error since that may block.
2366 thread->check_and_handle_async_exceptions(false);
2367 }
2368 }
2369
2370 // This is a variant of the normal
2371 // check_special_condition_for_native_trans with slightly different
2372 // semantics for use by critical native wrappers. It does all the
2373 // normal checks but also performs the transition back into
2374 // thread_in_Java state. This is required so that critical natives
2375 // can potentially block and perform a GC if they are the last thread
2376 // exiting the GC_locker.
2377 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2378 check_special_condition_for_native_trans(thread);
2379
2380 // Finish the transition
2381 thread->set_thread_state(_thread_in_Java);
2382
2383 if (thread->do_critical_native_unlock()) {
2384 ThreadInVMfromJavaNoAsyncException tiv(thread);
2385 GC_locker::unlock_critical(thread);
2386 thread->clear_critical_native_unlock();
2387 }
2388 }
2389
2390 // We need to guarantee the Threads_lock here, since resumes are not
2391 // allowed during safepoint synchronization
2392 // Can only resume from an external suspension
2393 void JavaThread::java_resume() {
2394 assert_locked_or_safepoint(Threads_lock);
2395
2396 // Sanity check: thread is gone, has started exiting or the thread
2397 // was not externally suspended.
2398 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2399 return;
2400 }
2401
2402 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2403
2404 clear_external_suspend();
2405
2406 if (is_ext_suspended()) {
2407 clear_ext_suspended();
2408 SR_lock()->notify_all();
2409 }
2410 }
2411
2412 void JavaThread::create_stack_guard_pages() {
2413 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2414 address low_addr = stack_base() - stack_size();
2415 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2416
2417 int allocate = os::allocate_stack_guard_pages();
2418 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2419
2420 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2421 warning("Attempt to allocate stack guard pages failed.");
2422 return;
2423 }
2424
2425 if (os::guard_memory((char *) low_addr, len)) {
2426 _stack_guard_state = stack_guard_enabled;
2427 } else {
2428 warning("Attempt to protect stack guard pages failed.");
2429 if (os::uncommit_memory((char *) low_addr, len)) {
2430 warning("Attempt to deallocate stack guard pages failed.");
2431 }
2432 }
2433 }
2434
2435 void JavaThread::remove_stack_guard_pages() {
2436 assert(Thread::current() == this, "from different thread");
2437 if (_stack_guard_state == stack_guard_unused) return;
2438 address low_addr = stack_base() - stack_size();
2439 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2440
2441 if (os::allocate_stack_guard_pages()) {
2442 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2443 _stack_guard_state = stack_guard_unused;
2444 } else {
2445 warning("Attempt to deallocate stack guard pages failed.");
2446 }
2447 } else {
2448 if (_stack_guard_state == stack_guard_unused) return;
2449 if (os::unguard_memory((char *) low_addr, len)) {
2450 _stack_guard_state = stack_guard_unused;
2451 } else {
2452 warning("Attempt to unprotect stack guard pages failed.");
2453 }
2454 }
2455 }
2456
2457 void JavaThread::enable_stack_yellow_zone() {
2458 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2459 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2460
2461 // The base notation is from the stacks point of view, growing downward.
2462 // We need to adjust it to work correctly with guard_memory()
2463 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2464
2465 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2466 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2467
2468 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2469 _stack_guard_state = stack_guard_enabled;
2470 } else {
2471 warning("Attempt to guard stack yellow zone failed.");
2472 }
2473 enable_register_stack_guard();
2474 }
2475
2476 void JavaThread::disable_stack_yellow_zone() {
2477 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2478 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2479
2480 // Simply return if called for a thread that does not use guard pages.
2481 if (_stack_guard_state == stack_guard_unused) return;
2482
2483 // The base notation is from the stacks point of view, growing downward.
2484 // We need to adjust it to work correctly with guard_memory()
2485 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2486
2487 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2488 _stack_guard_state = stack_guard_yellow_disabled;
2489 } else {
2490 warning("Attempt to unguard stack yellow zone failed.");
2491 }
2492 disable_register_stack_guard();
2493 }
2494
2495 void JavaThread::enable_stack_red_zone() {
2496 // The base notation is from the stacks point of view, growing downward.
2497 // We need to adjust it to work correctly with guard_memory()
2498 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2499 address base = stack_red_zone_base() - stack_red_zone_size();
2500
2501 guarantee(base < stack_base(), "Error calculating stack red zone");
2502 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2503
2504 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2505 warning("Attempt to guard stack red zone failed.");
2506 }
2507 }
2508
2509 void JavaThread::disable_stack_red_zone() {
2510 // The base notation is from the stacks point of view, growing downward.
2511 // We need to adjust it to work correctly with guard_memory()
2512 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2513 address base = stack_red_zone_base() - stack_red_zone_size();
2514 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2515 warning("Attempt to unguard stack red zone failed.");
2516 }
2517 }
2518
2519 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2520 // ignore is there is no stack
2521 if (!has_last_Java_frame()) return;
2522 // traverse the stack frames. Starts from top frame.
2523 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2524 frame* fr = fst.current();
2525 f(fr, fst.register_map());
2526 }
2527 }
2528
2529
2530 #ifndef PRODUCT
2531 // Deoptimization
2532 // Function for testing deoptimization
2533 void JavaThread::deoptimize() {
2534 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2535 StackFrameStream fst(this, UseBiasedLocking);
2536 bool deopt = false; // Dump stack only if a deopt actually happens.
2537 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2538 // Iterate over all frames in the thread and deoptimize
2539 for (; !fst.is_done(); fst.next()) {
2540 if (fst.current()->can_be_deoptimized()) {
2541
2542 if (only_at) {
2543 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2544 // consists of comma or carriage return separated numbers so
2545 // search for the current bci in that string.
2546 address pc = fst.current()->pc();
2547 nmethod* nm = (nmethod*) fst.current()->cb();
2548 ScopeDesc* sd = nm->scope_desc_at(pc);
2549 char buffer[8];
2550 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2551 size_t len = strlen(buffer);
2552 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2553 while (found != NULL) {
2554 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2555 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2556 // Check that the bci found is bracketed by terminators.
2557 break;
2558 }
2559 found = strstr(found + 1, buffer);
2560 }
2561 if (!found) {
2562 continue;
2563 }
2564 }
2565
2566 if (DebugDeoptimization && !deopt) {
2567 deopt = true; // One-time only print before deopt
2568 tty->print_cr("[BEFORE Deoptimization]");
2569 trace_frames();
2570 trace_stack();
2571 }
2572 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2573 }
2574 }
2575
2576 if (DebugDeoptimization && deopt) {
2577 tty->print_cr("[AFTER Deoptimization]");
2578 trace_frames();
2579 }
2580 }
2581
2582
2583 // Make zombies
2584 void JavaThread::make_zombies() {
2585 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2586 if (fst.current()->can_be_deoptimized()) {
2587 // it is a Java nmethod
2588 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2589 nm->make_not_entrant();
2590 }
2591 }
2592 }
2593 #endif // PRODUCT
2594
2595
2596 void JavaThread::deoptimized_wrt_marked_nmethods() {
2597 if (!has_last_Java_frame()) return;
2598 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2599 StackFrameStream fst(this, UseBiasedLocking);
2600 for (; !fst.is_done(); fst.next()) {
2601 if (fst.current()->should_be_deoptimized()) {
2602 if (LogCompilation && xtty != NULL) {
2603 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2604 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2605 this->name(), nm != NULL ? nm->compile_id() : -1);
2606 }
2607
2608 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2609 }
2610 }
2611 }
2612
2613
2614 // If the caller is a NamedThread, then remember, in the current scope,
2615 // the given JavaThread in its _processed_thread field.
2616 class RememberProcessedThread: public StackObj {
2617 NamedThread* _cur_thr;
2618 public:
2619 RememberProcessedThread(JavaThread* jthr) {
2620 Thread* thread = Thread::current();
2621 if (thread->is_Named_thread()) {
2622 _cur_thr = (NamedThread *)thread;
2623 _cur_thr->set_processed_thread(jthr);
2624 } else {
2625 _cur_thr = NULL;
2626 }
2627 }
2628
2629 ~RememberProcessedThread() {
2630 if (_cur_thr) {
2631 _cur_thr->set_processed_thread(NULL);
2632 }
2633 }
2634 };
2635
2636 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2637 // Verify that the deferred card marks have been flushed.
2638 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2639
2640 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2641 // since there may be more than one thread using each ThreadProfiler.
2642
2643 // Traverse the GCHandles
2644 Thread::oops_do(f, cld_f, cf);
2645
2646 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2647 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2648
2649 if (has_last_Java_frame()) {
2650 // Record JavaThread to GC thread
2651 RememberProcessedThread rpt(this);
2652
2653 // Traverse the privileged stack
2654 if (_privileged_stack_top != NULL) {
2655 _privileged_stack_top->oops_do(f);
2656 }
2657
2658 // traverse the registered growable array
2659 if (_array_for_gc != NULL) {
2660 for (int index = 0; index < _array_for_gc->length(); index++) {
2661 f->do_oop(_array_for_gc->adr_at(index));
2662 }
2663 }
2664
2665 // Traverse the monitor chunks
2666 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2667 chunk->oops_do(f);
2668 }
2669
2670 // Traverse the execution stack
2671 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2672 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2673 }
2674 }
2675
2676 // callee_target is never live across a gc point so NULL it here should
2677 // it still contain a methdOop.
2678
2679 set_callee_target(NULL);
2680
2681 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2682 // If we have deferred set_locals there might be oops waiting to be
2683 // written
2684 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2685 if (list != NULL) {
2686 for (int i = 0; i < list->length(); i++) {
2687 list->at(i)->oops_do(f);
2688 }
2689 }
2690
2691 // Traverse instance variables at the end since the GC may be moving things
2692 // around using this function
2693 f->do_oop((oop*) &_threadObj);
2694 f->do_oop((oop*) &_vm_result);
2695 f->do_oop((oop*) &_exception_oop);
2696 f->do_oop((oop*) &_pending_async_exception);
2697
2698 if (jvmti_thread_state() != NULL) {
2699 jvmti_thread_state()->oops_do(f);
2700 }
2701 }
2702
2703 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2704 Thread::nmethods_do(cf); // (super method is a no-op)
2705
2706 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2707 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2708
2709 if (has_last_Java_frame()) {
2710 // Traverse the execution stack
2711 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2712 fst.current()->nmethods_do(cf);
2713 }
2714 }
2715 }
2716
2717 void JavaThread::metadata_do(void f(Metadata*)) {
2718 if (has_last_Java_frame()) {
2719 // Traverse the execution stack to call f() on the methods in the stack
2720 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2721 fst.current()->metadata_do(f);
2722 }
2723 } else if (is_Compiler_thread()) {
2724 // need to walk ciMetadata in current compile tasks to keep alive.
2725 CompilerThread* ct = (CompilerThread*)this;
2726 if (ct->env() != NULL) {
2727 ct->env()->metadata_do(f);
2728 }
2729 }
2730 }
2731
2732 // Printing
2733 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2734 switch (_thread_state) {
2735 case _thread_uninitialized: return "_thread_uninitialized";
2736 case _thread_new: return "_thread_new";
2737 case _thread_new_trans: return "_thread_new_trans";
2738 case _thread_in_native: return "_thread_in_native";
2739 case _thread_in_native_trans: return "_thread_in_native_trans";
2740 case _thread_in_vm: return "_thread_in_vm";
2741 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2742 case _thread_in_Java: return "_thread_in_Java";
2743 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2744 case _thread_blocked: return "_thread_blocked";
2745 case _thread_blocked_trans: return "_thread_blocked_trans";
2746 default: return "unknown thread state";
2747 }
2748 }
2749
2750 #ifndef PRODUCT
2751 void JavaThread::print_thread_state_on(outputStream *st) const {
2752 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2753 };
2754 void JavaThread::print_thread_state() const {
2755 print_thread_state_on(tty);
2756 }
2757 #endif // PRODUCT
2758
2759 // Called by Threads::print() for VM_PrintThreads operation
2760 void JavaThread::print_on(outputStream *st) const {
2761 st->print("\"%s\" ", get_thread_name());
2762 oop thread_oop = threadObj();
2763 if (thread_oop != NULL) {
2764 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2765 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2766 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2767 }
2768 Thread::print_on(st);
2769 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2770 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2771 if (thread_oop != NULL) {
2772 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2773 }
2774 #ifndef PRODUCT
2775 print_thread_state_on(st);
2776 _safepoint_state->print_on(st);
2777 #endif // PRODUCT
2778 }
2779
2780 // Called by fatal error handler. The difference between this and
2781 // JavaThread::print() is that we can't grab lock or allocate memory.
2782 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2783 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2784 oop thread_obj = threadObj();
2785 if (thread_obj != NULL) {
2786 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2787 }
2788 st->print(" [");
2789 st->print("%s", _get_thread_state_name(_thread_state));
2790 if (osthread()) {
2791 st->print(", id=%d", osthread()->thread_id());
2792 }
2793 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2794 _stack_base - _stack_size, _stack_base);
2795 st->print("]");
2796 return;
2797 }
2798
2799 // Verification
2800
2801 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2802
2803 void JavaThread::verify() {
2804 // Verify oops in the thread.
2805 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2806
2807 // Verify the stack frames.
2808 frames_do(frame_verify);
2809 }
2810
2811 // CR 6300358 (sub-CR 2137150)
2812 // Most callers of this method assume that it can't return NULL but a
2813 // thread may not have a name whilst it is in the process of attaching to
2814 // the VM - see CR 6412693, and there are places where a JavaThread can be
2815 // seen prior to having it's threadObj set (eg JNI attaching threads and
2816 // if vm exit occurs during initialization). These cases can all be accounted
2817 // for such that this method never returns NULL.
2818 const char* JavaThread::get_thread_name() const {
2819 #ifdef ASSERT
2820 // early safepoints can hit while current thread does not yet have TLS
2821 if (!SafepointSynchronize::is_at_safepoint()) {
2822 Thread *cur = Thread::current();
2823 if (!(cur->is_Java_thread() && cur == this)) {
2824 // Current JavaThreads are allowed to get their own name without
2825 // the Threads_lock.
2826 assert_locked_or_safepoint(Threads_lock);
2827 }
2828 }
2829 #endif // ASSERT
2830 return get_thread_name_string();
2831 }
2832
2833 // Returns a non-NULL representation of this thread's name, or a suitable
2834 // descriptive string if there is no set name
2835 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2836 const char* name_str;
2837 oop thread_obj = threadObj();
2838 if (thread_obj != NULL) {
2839 oop name = java_lang_Thread::name(thread_obj);
2840 if (name != NULL) {
2841 if (buf == NULL) {
2842 name_str = java_lang_String::as_utf8_string(name);
2843 } else {
2844 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2845 }
2846 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2847 name_str = "<no-name - thread is attaching>";
2848 } else {
2849 name_str = Thread::name();
2850 }
2851 } else {
2852 name_str = Thread::name();
2853 }
2854 assert(name_str != NULL, "unexpected NULL thread name");
2855 return name_str;
2856 }
2857
2858
2859 const char* JavaThread::get_threadgroup_name() const {
2860 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2861 oop thread_obj = threadObj();
2862 if (thread_obj != NULL) {
2863 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2864 if (thread_group != NULL) {
2865 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2866 // ThreadGroup.name can be null
2867 if (name != NULL) {
2868 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2869 return str;
2870 }
2871 }
2872 }
2873 return NULL;
2874 }
2875
2876 const char* JavaThread::get_parent_name() const {
2877 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2878 oop thread_obj = threadObj();
2879 if (thread_obj != NULL) {
2880 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2881 if (thread_group != NULL) {
2882 oop parent = java_lang_ThreadGroup::parent(thread_group);
2883 if (parent != NULL) {
2884 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2885 // ThreadGroup.name can be null
2886 if (name != NULL) {
2887 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2888 return str;
2889 }
2890 }
2891 }
2892 }
2893 return NULL;
2894 }
2895
2896 ThreadPriority JavaThread::java_priority() const {
2897 oop thr_oop = threadObj();
2898 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2899 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2900 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2901 return priority;
2902 }
2903
2904 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2905
2906 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2907 // Link Java Thread object <-> C++ Thread
2908
2909 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2910 // and put it into a new Handle. The Handle "thread_oop" can then
2911 // be used to pass the C++ thread object to other methods.
2912
2913 // Set the Java level thread object (jthread) field of the
2914 // new thread (a JavaThread *) to C++ thread object using the
2915 // "thread_oop" handle.
2916
2917 // Set the thread field (a JavaThread *) of the
2918 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2919
2920 Handle thread_oop(Thread::current(),
2921 JNIHandles::resolve_non_null(jni_thread));
2922 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2923 "must be initialized");
2924 set_threadObj(thread_oop());
2925 java_lang_Thread::set_thread(thread_oop(), this);
2926
2927 if (prio == NoPriority) {
2928 prio = java_lang_Thread::priority(thread_oop());
2929 assert(prio != NoPriority, "A valid priority should be present");
2930 }
2931
2932 // Push the Java priority down to the native thread; needs Threads_lock
2933 Thread::set_priority(this, prio);
2934
2935 prepare_ext();
2936
2937 // Add the new thread to the Threads list and set it in motion.
2938 // We must have threads lock in order to call Threads::add.
2939 // It is crucial that we do not block before the thread is
2940 // added to the Threads list for if a GC happens, then the java_thread oop
2941 // will not be visited by GC.
2942 Threads::add(this);
2943 }
2944
2945 oop JavaThread::current_park_blocker() {
2946 // Support for JSR-166 locks
2947 oop thread_oop = threadObj();
2948 if (thread_oop != NULL &&
2949 JDK_Version::current().supports_thread_park_blocker()) {
2950 return java_lang_Thread::park_blocker(thread_oop);
2951 }
2952 return NULL;
2953 }
2954
2955
2956 void JavaThread::print_stack_on(outputStream* st) {
2957 if (!has_last_Java_frame()) return;
2958 ResourceMark rm;
2959 HandleMark hm;
2960
2961 RegisterMap reg_map(this);
2962 vframe* start_vf = last_java_vframe(®_map);
2963 int count = 0;
2964 for (vframe* f = start_vf; f; f = f->sender()) {
2965 if (f->is_java_frame()) {
2966 javaVFrame* jvf = javaVFrame::cast(f);
2967 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2968
2969 // Print out lock information
2970 if (JavaMonitorsInStackTrace) {
2971 jvf->print_lock_info_on(st, count);
2972 }
2973 } else {
2974 // Ignore non-Java frames
2975 }
2976
2977 // Bail-out case for too deep stacks
2978 count++;
2979 if (MaxJavaStackTraceDepth == count) return;
2980 }
2981 }
2982
2983
2984 // JVMTI PopFrame support
2985 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2986 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2987 if (in_bytes(size_in_bytes) != 0) {
2988 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
2989 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2990 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2991 }
2992 }
2993
2994 void* JavaThread::popframe_preserved_args() {
2995 return _popframe_preserved_args;
2996 }
2997
2998 ByteSize JavaThread::popframe_preserved_args_size() {
2999 return in_ByteSize(_popframe_preserved_args_size);
3000 }
3001
3002 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3003 int sz = in_bytes(popframe_preserved_args_size());
3004 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3005 return in_WordSize(sz / wordSize);
3006 }
3007
3008 void JavaThread::popframe_free_preserved_args() {
3009 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3010 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3011 _popframe_preserved_args = NULL;
3012 _popframe_preserved_args_size = 0;
3013 }
3014
3015 #ifndef PRODUCT
3016
3017 void JavaThread::trace_frames() {
3018 tty->print_cr("[Describe stack]");
3019 int frame_no = 1;
3020 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3021 tty->print(" %d. ", frame_no++);
3022 fst.current()->print_value_on(tty, this);
3023 tty->cr();
3024 }
3025 }
3026
3027 class PrintAndVerifyOopClosure: public OopClosure {
3028 protected:
3029 template <class T> inline void do_oop_work(T* p) {
3030 oop obj = oopDesc::load_decode_heap_oop(p);
3031 if (obj == NULL) return;
3032 tty->print(INTPTR_FORMAT ": ", p);
3033 if (obj->is_oop_or_null()) {
3034 if (obj->is_objArray()) {
3035 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3036 } else {
3037 obj->print();
3038 }
3039 } else {
3040 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3041 }
3042 tty->cr();
3043 }
3044 public:
3045 virtual void do_oop(oop* p) { do_oop_work(p); }
3046 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3047 };
3048
3049
3050 static void oops_print(frame* f, const RegisterMap *map) {
3051 PrintAndVerifyOopClosure print;
3052 f->print_value();
3053 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3054 }
3055
3056 // Print our all the locations that contain oops and whether they are
3057 // valid or not. This useful when trying to find the oldest frame
3058 // where an oop has gone bad since the frame walk is from youngest to
3059 // oldest.
3060 void JavaThread::trace_oops() {
3061 tty->print_cr("[Trace oops]");
3062 frames_do(oops_print);
3063 }
3064
3065
3066 #ifdef ASSERT
3067 // Print or validate the layout of stack frames
3068 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3069 ResourceMark rm;
3070 PRESERVE_EXCEPTION_MARK;
3071 FrameValues values;
3072 int frame_no = 0;
3073 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3074 fst.current()->describe(values, ++frame_no);
3075 if (depth == frame_no) break;
3076 }
3077 if (validate_only) {
3078 values.validate();
3079 } else {
3080 tty->print_cr("[Describe stack layout]");
3081 values.print(this);
3082 }
3083 }
3084 #endif
3085
3086 void JavaThread::trace_stack_from(vframe* start_vf) {
3087 ResourceMark rm;
3088 int vframe_no = 1;
3089 for (vframe* f = start_vf; f; f = f->sender()) {
3090 if (f->is_java_frame()) {
3091 javaVFrame::cast(f)->print_activation(vframe_no++);
3092 } else {
3093 f->print();
3094 }
3095 if (vframe_no > StackPrintLimit) {
3096 tty->print_cr("...<more frames>...");
3097 return;
3098 }
3099 }
3100 }
3101
3102
3103 void JavaThread::trace_stack() {
3104 if (!has_last_Java_frame()) return;
3105 ResourceMark rm;
3106 HandleMark hm;
3107 RegisterMap reg_map(this);
3108 trace_stack_from(last_java_vframe(®_map));
3109 }
3110
3111
3112 #endif // PRODUCT
3113
3114
3115 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3116 assert(reg_map != NULL, "a map must be given");
3117 frame f = last_frame();
3118 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3119 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3120 }
3121 return NULL;
3122 }
3123
3124
3125 Klass* JavaThread::security_get_caller_class(int depth) {
3126 vframeStream vfst(this);
3127 vfst.security_get_caller_frame(depth);
3128 if (!vfst.at_end()) {
3129 return vfst.method()->method_holder();
3130 }
3131 return NULL;
3132 }
3133
3134 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3135 assert(thread->is_Compiler_thread(), "must be compiler thread");
3136 CompileBroker::compiler_thread_loop();
3137 }
3138
3139 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3140 NMethodSweeper::sweeper_loop();
3141 }
3142
3143 // Create a CompilerThread
3144 CompilerThread::CompilerThread(CompileQueue* queue,
3145 CompilerCounters* counters)
3146 : JavaThread(&compiler_thread_entry) {
3147 _env = NULL;
3148 _log = NULL;
3149 _task = NULL;
3150 _queue = queue;
3151 _counters = counters;
3152 _buffer_blob = NULL;
3153 _compiler = NULL;
3154
3155 #ifndef PRODUCT
3156 _ideal_graph_printer = NULL;
3157 #endif
3158 }
3159
3160 // Create sweeper thread
3161 CodeCacheSweeperThread::CodeCacheSweeperThread()
3162 : JavaThread(&sweeper_thread_entry) {
3163 _scanned_nmethod = NULL;
3164 }
3165 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3166 JavaThread::oops_do(f, cld_f, cf);
3167 if (_scanned_nmethod != NULL && cf != NULL) {
3168 // Safepoints can occur when the sweeper is scanning an nmethod so
3169 // process it here to make sure it isn't unloaded in the middle of
3170 // a scan.
3171 cf->do_code_blob(_scanned_nmethod);
3172 }
3173 }
3174
3175
3176 // ======= Threads ========
3177
3178 // The Threads class links together all active threads, and provides
3179 // operations over all threads. It is protected by its own Mutex
3180 // lock, which is also used in other contexts to protect thread
3181 // operations from having the thread being operated on from exiting
3182 // and going away unexpectedly (e.g., safepoint synchronization)
3183
3184 JavaThread* Threads::_thread_list = NULL;
3185 int Threads::_number_of_threads = 0;
3186 int Threads::_number_of_non_daemon_threads = 0;
3187 int Threads::_return_code = 0;
3188 int Threads::_thread_claim_parity = 0;
3189 size_t JavaThread::_stack_size_at_create = 0;
3190 #ifdef ASSERT
3191 bool Threads::_vm_complete = false;
3192 #endif
3193
3194 // All JavaThreads
3195 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3196
3197 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3198 void Threads::threads_do(ThreadClosure* tc) {
3199 assert_locked_or_safepoint(Threads_lock);
3200 // ALL_JAVA_THREADS iterates through all JavaThreads
3201 ALL_JAVA_THREADS(p) {
3202 tc->do_thread(p);
3203 }
3204 // Someday we could have a table or list of all non-JavaThreads.
3205 // For now, just manually iterate through them.
3206 tc->do_thread(VMThread::vm_thread());
3207 Universe::heap()->gc_threads_do(tc);
3208 WatcherThread *wt = WatcherThread::watcher_thread();
3209 // Strictly speaking, the following NULL check isn't sufficient to make sure
3210 // the data for WatcherThread is still valid upon being examined. However,
3211 // considering that WatchThread terminates when the VM is on the way to
3212 // exit at safepoint, the chance of the above is extremely small. The right
3213 // way to prevent termination of WatcherThread would be to acquire
3214 // Terminator_lock, but we can't do that without violating the lock rank
3215 // checking in some cases.
3216 if (wt != NULL) {
3217 tc->do_thread(wt);
3218 }
3219
3220 // If CompilerThreads ever become non-JavaThreads, add them here
3221 }
3222
3223 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3224 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3225
3226 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3227 create_vm_init_libraries();
3228 }
3229
3230 initialize_class(vmSymbols::java_lang_String(), CHECK);
3231
3232 // Initialize java_lang.System (needed before creating the thread)
3233 initialize_class(vmSymbols::java_lang_System(), CHECK);
3234 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3235 Handle thread_group = create_initial_thread_group(CHECK);
3236 Universe::set_main_thread_group(thread_group());
3237 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3238 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3239 main_thread->set_threadObj(thread_object);
3240 // Set thread status to running since main thread has
3241 // been started and running.
3242 java_lang_Thread::set_thread_status(thread_object,
3243 java_lang_Thread::RUNNABLE);
3244
3245 // The VM creates & returns objects of this class. Make sure it's initialized.
3246 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3247
3248 // The VM preresolves methods to these classes. Make sure that they get initialized
3249 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3250 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3251 call_initializeSystemClass(CHECK);
3252
3253 // get the Java runtime name after java.lang.System is initialized
3254 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3255 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3256
3257 // an instance of OutOfMemory exception has been allocated earlier
3258 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3259 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3260 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3261 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3262 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3263 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3264 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3265 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3266 }
3267
3268 void Threads::initialize_jsr292_core_classes(TRAPS) {
3269 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3270 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3271 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3272 }
3273
3274 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3275 extern void JDK_Version_init();
3276
3277 // Check version
3278 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3279
3280 // Initialize the output stream module
3281 ostream_init();
3282
3283 // Process java launcher properties.
3284 Arguments::process_sun_java_launcher_properties(args);
3285
3286 // Initialize the os module before using TLS
3287 os::init();
3288
3289 // Initialize system properties.
3290 Arguments::init_system_properties();
3291
3292 // So that JDK version can be used as a discriminator when parsing arguments
3293 JDK_Version_init();
3294
3295 // Update/Initialize System properties after JDK version number is known
3296 Arguments::init_version_specific_system_properties();
3297
3298 // Parse arguments
3299 jint parse_result = Arguments::parse(args);
3300 if (parse_result != JNI_OK) return parse_result;
3301
3302 os::init_before_ergo();
3303
3304 jint ergo_result = Arguments::apply_ergo();
3305 if (ergo_result != JNI_OK) return ergo_result;
3306
3307 if (PauseAtStartup) {
3308 os::pause();
3309 }
3310
3311 HOTSPOT_VM_INIT_BEGIN();
3312
3313 // Record VM creation timing statistics
3314 TraceVmCreationTime create_vm_timer;
3315 create_vm_timer.start();
3316
3317 // Timing (must come after argument parsing)
3318 TraceTime timer("Create VM", TraceStartupTime);
3319
3320 // Initialize the os module after parsing the args
3321 jint os_init_2_result = os::init_2();
3322 if (os_init_2_result != JNI_OK) return os_init_2_result;
3323
3324 jint adjust_after_os_result = Arguments::adjust_after_os();
3325 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3326
3327 // initialize TLS
3328 ThreadLocalStorage::init();
3329
3330 // Initialize output stream logging
3331 ostream_init_log();
3332
3333 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3334 // Must be before create_vm_init_agents()
3335 if (Arguments::init_libraries_at_startup()) {
3336 convert_vm_init_libraries_to_agents();
3337 }
3338
3339 // Launch -agentlib/-agentpath and converted -Xrun agents
3340 if (Arguments::init_agents_at_startup()) {
3341 create_vm_init_agents();
3342 }
3343
3344 // Initialize Threads state
3345 _thread_list = NULL;
3346 _number_of_threads = 0;
3347 _number_of_non_daemon_threads = 0;
3348
3349 // Initialize global data structures and create system classes in heap
3350 vm_init_globals();
3351
3352 // Attach the main thread to this os thread
3353 JavaThread* main_thread = new JavaThread();
3354 main_thread->set_thread_state(_thread_in_vm);
3355 // must do this before set_active_handles and initialize_thread_local_storage
3356 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3357 // change the stack size recorded here to one based on the java thread
3358 // stacksize. This adjusted size is what is used to figure the placement
3359 // of the guard pages.
3360 main_thread->record_stack_base_and_size();
3361 main_thread->initialize_thread_local_storage();
3362
3363 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3364
3365 if (!main_thread->set_as_starting_thread()) {
3366 vm_shutdown_during_initialization(
3367 "Failed necessary internal allocation. Out of swap space");
3368 delete main_thread;
3369 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3370 return JNI_ENOMEM;
3371 }
3372
3373 // Enable guard page *after* os::create_main_thread(), otherwise it would
3374 // crash Linux VM, see notes in os_linux.cpp.
3375 main_thread->create_stack_guard_pages();
3376
3377 // Initialize Java-Level synchronization subsystem
3378 ObjectMonitor::Initialize();
3379
3380 // Initialize global modules
3381 jint status = init_globals();
3382 if (status != JNI_OK) {
3383 delete main_thread;
3384 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3385 return status;
3386 }
3387
3388 // Should be done after the heap is fully created
3389 main_thread->cache_global_variables();
3390
3391 HandleMark hm;
3392
3393 { MutexLocker mu(Threads_lock);
3394 Threads::add(main_thread);
3395 }
3396
3397 // Any JVMTI raw monitors entered in onload will transition into
3398 // real raw monitor. VM is setup enough here for raw monitor enter.
3399 JvmtiExport::transition_pending_onload_raw_monitors();
3400
3401 // Create the VMThread
3402 { TraceTime timer("Start VMThread", TraceStartupTime);
3403 VMThread::create();
3404 Thread* vmthread = VMThread::vm_thread();
3405
3406 if (!os::create_thread(vmthread, os::vm_thread)) {
3407 vm_exit_during_initialization("Cannot create VM thread. "
3408 "Out of system resources.");
3409 }
3410
3411 // Wait for the VM thread to become ready, and VMThread::run to initialize
3412 // Monitors can have spurious returns, must always check another state flag
3413 {
3414 MutexLocker ml(Notify_lock);
3415 os::start_thread(vmthread);
3416 while (vmthread->active_handles() == NULL) {
3417 Notify_lock->wait();
3418 }
3419 }
3420 }
3421
3422 assert(Universe::is_fully_initialized(), "not initialized");
3423 if (VerifyDuringStartup) {
3424 // Make sure we're starting with a clean slate.
3425 VM_Verify verify_op;
3426 VMThread::execute(&verify_op);
3427 }
3428
3429 Thread* THREAD = Thread::current();
3430
3431 // At this point, the Universe is initialized, but we have not executed
3432 // any byte code. Now is a good time (the only time) to dump out the
3433 // internal state of the JVM for sharing.
3434 if (DumpSharedSpaces) {
3435 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3436 ShouldNotReachHere();
3437 }
3438
3439 // Always call even when there are not JVMTI environments yet, since environments
3440 // may be attached late and JVMTI must track phases of VM execution
3441 JvmtiExport::enter_start_phase();
3442
3443 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3444 JvmtiExport::post_vm_start();
3445
3446 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3447
3448 // We need this for ClassDataSharing - the initial vm.info property is set
3449 // with the default value of CDS "sharing" which may be reset through
3450 // command line options.
3451 reset_vm_info_property(CHECK_JNI_ERR);
3452
3453 quicken_jni_functions();
3454
3455 // Must be run after init_ft which initializes ft_enabled
3456 if (TRACE_INITIALIZE() != JNI_OK) {
3457 vm_exit_during_initialization("Failed to initialize tracing backend");
3458 }
3459
3460 // Set flag that basic initialization has completed. Used by exceptions and various
3461 // debug stuff, that does not work until all basic classes have been initialized.
3462 set_init_completed();
3463
3464 Metaspace::post_initialize();
3465
3466 HOTSPOT_VM_INIT_END();
3467
3468 // record VM initialization completion time
3469 #if INCLUDE_MANAGEMENT
3470 Management::record_vm_init_completed();
3471 #endif // INCLUDE_MANAGEMENT
3472
3473 // Compute system loader. Note that this has to occur after set_init_completed, since
3474 // valid exceptions may be thrown in the process.
3475 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3476 // set_init_completed has just been called, causing exceptions not to be shortcut
3477 // anymore. We call vm_exit_during_initialization directly instead.
3478 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3479
3480 #if INCLUDE_ALL_GCS
3481 // Support for ConcurrentMarkSweep. This should be cleaned up
3482 // and better encapsulated. The ugly nested if test would go away
3483 // once things are properly refactored. XXX YSR
3484 if (UseConcMarkSweepGC || UseG1GC) {
3485 if (UseConcMarkSweepGC) {
3486 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3487 } else {
3488 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3489 }
3490 }
3491 #endif // INCLUDE_ALL_GCS
3492
3493 // Always call even when there are not JVMTI environments yet, since environments
3494 // may be attached late and JVMTI must track phases of VM execution
3495 JvmtiExport::enter_live_phase();
3496
3497 // Signal Dispatcher needs to be started before VMInit event is posted
3498 os::signal_init();
3499
3500 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3501 if (!DisableAttachMechanism) {
3502 AttachListener::vm_start();
3503 if (StartAttachListener || AttachListener::init_at_startup()) {
3504 AttachListener::init();
3505 }
3506 }
3507
3508 // Launch -Xrun agents
3509 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3510 // back-end can launch with -Xdebug -Xrunjdwp.
3511 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3512 create_vm_init_libraries();
3513 }
3514
3515 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3516 JvmtiExport::post_vm_initialized();
3517
3518 if (TRACE_START() != JNI_OK) {
3519 vm_exit_during_initialization("Failed to start tracing backend.");
3520 }
3521
3522 if (CleanChunkPoolAsync) {
3523 Chunk::start_chunk_pool_cleaner_task();
3524 }
3525
3526 // initialize compiler(s)
3527 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3528 CompileBroker::compilation_init();
3529 #endif
3530
3531 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3532 // It is done after compilers are initialized, because otherwise compilations of
3533 // signature polymorphic MH intrinsics can be missed
3534 // (see SystemDictionary::find_method_handle_intrinsic).
3535 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3536
3537 #if INCLUDE_MANAGEMENT
3538 Management::initialize(THREAD);
3539
3540 if (HAS_PENDING_EXCEPTION) {
3541 // management agent fails to start possibly due to
3542 // configuration problem and is responsible for printing
3543 // stack trace if appropriate. Simply exit VM.
3544 vm_exit(1);
3545 }
3546 #endif // INCLUDE_MANAGEMENT
3547
3548 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3549 if (MemProfiling) MemProfiler::engage();
3550 StatSampler::engage();
3551 if (CheckJNICalls) JniPeriodicChecker::engage();
3552
3553 BiasedLocking::init();
3554
3555 #if INCLUDE_RTM_OPT
3556 RTMLockingCounters::init();
3557 #endif
3558
3559 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3560 call_postVMInitHook(THREAD);
3561 // The Java side of PostVMInitHook.run must deal with all
3562 // exceptions and provide means of diagnosis.
3563 if (HAS_PENDING_EXCEPTION) {
3564 CLEAR_PENDING_EXCEPTION;
3565 }
3566 }
3567
3568 {
3569 MutexLocker ml(PeriodicTask_lock);
3570 // Make sure the WatcherThread can be started by WatcherThread::start()
3571 // or by dynamic enrollment.
3572 WatcherThread::make_startable();
3573 // Start up the WatcherThread if there are any periodic tasks
3574 // NOTE: All PeriodicTasks should be registered by now. If they
3575 // aren't, late joiners might appear to start slowly (we might
3576 // take a while to process their first tick).
3577 if (PeriodicTask::num_tasks() > 0) {
3578 WatcherThread::start();
3579 }
3580 }
3581
3582 create_vm_timer.end();
3583 #ifdef ASSERT
3584 _vm_complete = true;
3585 #endif
3586 return JNI_OK;
3587 }
3588
3589 // type for the Agent_OnLoad and JVM_OnLoad entry points
3590 extern "C" {
3591 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3592 }
3593 // Find a command line agent library and return its entry point for
3594 // -agentlib: -agentpath: -Xrun
3595 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3596 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3597 const char *on_load_symbols[],
3598 size_t num_symbol_entries) {
3599 OnLoadEntry_t on_load_entry = NULL;
3600 void *library = NULL;
3601
3602 if (!agent->valid()) {
3603 char buffer[JVM_MAXPATHLEN];
3604 char ebuf[1024] = "";
3605 const char *name = agent->name();
3606 const char *msg = "Could not find agent library ";
3607
3608 // First check to see if agent is statically linked into executable
3609 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3610 library = agent->os_lib();
3611 } else if (agent->is_absolute_path()) {
3612 library = os::dll_load(name, ebuf, sizeof ebuf);
3613 if (library == NULL) {
3614 const char *sub_msg = " in absolute path, with error: ";
3615 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3616 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3617 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3618 // If we can't find the agent, exit.
3619 vm_exit_during_initialization(buf, NULL);
3620 FREE_C_HEAP_ARRAY(char, buf);
3621 }
3622 } else {
3623 // Try to load the agent from the standard dll directory
3624 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3625 name)) {
3626 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3627 }
3628 if (library == NULL) { // Try the local directory
3629 char ns[1] = {0};
3630 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3631 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3632 }
3633 if (library == NULL) {
3634 const char *sub_msg = " on the library path, with error: ";
3635 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3636 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3637 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3638 // If we can't find the agent, exit.
3639 vm_exit_during_initialization(buf, NULL);
3640 FREE_C_HEAP_ARRAY(char, buf);
3641 }
3642 }
3643 }
3644 agent->set_os_lib(library);
3645 agent->set_valid();
3646 }
3647
3648 // Find the OnLoad function.
3649 on_load_entry =
3650 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3651 false,
3652 on_load_symbols,
3653 num_symbol_entries));
3654 return on_load_entry;
3655 }
3656
3657 // Find the JVM_OnLoad entry point
3658 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3659 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3660 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3661 }
3662
3663 // Find the Agent_OnLoad entry point
3664 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3665 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3666 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3667 }
3668
3669 // For backwards compatibility with -Xrun
3670 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3671 // treated like -agentpath:
3672 // Must be called before agent libraries are created
3673 void Threads::convert_vm_init_libraries_to_agents() {
3674 AgentLibrary* agent;
3675 AgentLibrary* next;
3676
3677 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3678 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3679 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3680
3681 // If there is an JVM_OnLoad function it will get called later,
3682 // otherwise see if there is an Agent_OnLoad
3683 if (on_load_entry == NULL) {
3684 on_load_entry = lookup_agent_on_load(agent);
3685 if (on_load_entry != NULL) {
3686 // switch it to the agent list -- so that Agent_OnLoad will be called,
3687 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3688 Arguments::convert_library_to_agent(agent);
3689 } else {
3690 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3691 }
3692 }
3693 }
3694 }
3695
3696 // Create agents for -agentlib: -agentpath: and converted -Xrun
3697 // Invokes Agent_OnLoad
3698 // Called very early -- before JavaThreads exist
3699 void Threads::create_vm_init_agents() {
3700 extern struct JavaVM_ main_vm;
3701 AgentLibrary* agent;
3702
3703 JvmtiExport::enter_onload_phase();
3704
3705 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3706 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3707
3708 if (on_load_entry != NULL) {
3709 // Invoke the Agent_OnLoad function
3710 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3711 if (err != JNI_OK) {
3712 vm_exit_during_initialization("agent library failed to init", agent->name());
3713 }
3714 } else {
3715 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3716 }
3717 }
3718 JvmtiExport::enter_primordial_phase();
3719 }
3720
3721 extern "C" {
3722 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3723 }
3724
3725 void Threads::shutdown_vm_agents() {
3726 // Send any Agent_OnUnload notifications
3727 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3728 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3729 extern struct JavaVM_ main_vm;
3730 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3731
3732 // Find the Agent_OnUnload function.
3733 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3734 os::find_agent_function(agent,
3735 false,
3736 on_unload_symbols,
3737 num_symbol_entries));
3738
3739 // Invoke the Agent_OnUnload function
3740 if (unload_entry != NULL) {
3741 JavaThread* thread = JavaThread::current();
3742 ThreadToNativeFromVM ttn(thread);
3743 HandleMark hm(thread);
3744 (*unload_entry)(&main_vm);
3745 }
3746 }
3747 }
3748
3749 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3750 // Invokes JVM_OnLoad
3751 void Threads::create_vm_init_libraries() {
3752 extern struct JavaVM_ main_vm;
3753 AgentLibrary* agent;
3754
3755 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3756 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3757
3758 if (on_load_entry != NULL) {
3759 // Invoke the JVM_OnLoad function
3760 JavaThread* thread = JavaThread::current();
3761 ThreadToNativeFromVM ttn(thread);
3762 HandleMark hm(thread);
3763 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3764 if (err != JNI_OK) {
3765 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3766 }
3767 } else {
3768 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3769 }
3770 }
3771 }
3772
3773 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3774 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3775
3776 JavaThread* java_thread = NULL;
3777 // Sequential search for now. Need to do better optimization later.
3778 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3779 oop tobj = thread->threadObj();
3780 if (!thread->is_exiting() &&
3781 tobj != NULL &&
3782 java_tid == java_lang_Thread::thread_id(tobj)) {
3783 java_thread = thread;
3784 break;
3785 }
3786 }
3787 return java_thread;
3788 }
3789
3790
3791 // Last thread running calls java.lang.Shutdown.shutdown()
3792 void JavaThread::invoke_shutdown_hooks() {
3793 HandleMark hm(this);
3794
3795 // We could get here with a pending exception, if so clear it now.
3796 if (this->has_pending_exception()) {
3797 this->clear_pending_exception();
3798 }
3799
3800 EXCEPTION_MARK;
3801 Klass* k =
3802 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3803 THREAD);
3804 if (k != NULL) {
3805 // SystemDictionary::resolve_or_null will return null if there was
3806 // an exception. If we cannot load the Shutdown class, just don't
3807 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3808 // and finalizers (if runFinalizersOnExit is set) won't be run.
3809 // Note that if a shutdown hook was registered or runFinalizersOnExit
3810 // was called, the Shutdown class would have already been loaded
3811 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3812 instanceKlassHandle shutdown_klass (THREAD, k);
3813 JavaValue result(T_VOID);
3814 JavaCalls::call_static(&result,
3815 shutdown_klass,
3816 vmSymbols::shutdown_method_name(),
3817 vmSymbols::void_method_signature(),
3818 THREAD);
3819 }
3820 CLEAR_PENDING_EXCEPTION;
3821 }
3822
3823 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3824 // the program falls off the end of main(). Another VM exit path is through
3825 // vm_exit() when the program calls System.exit() to return a value or when
3826 // there is a serious error in VM. The two shutdown paths are not exactly
3827 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3828 // and VM_Exit op at VM level.
3829 //
3830 // Shutdown sequence:
3831 // + Shutdown native memory tracking if it is on
3832 // + Wait until we are the last non-daemon thread to execute
3833 // <-- every thing is still working at this moment -->
3834 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3835 // shutdown hooks, run finalizers if finalization-on-exit
3836 // + Call before_exit(), prepare for VM exit
3837 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3838 // currently the only user of this mechanism is File.deleteOnExit())
3839 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3840 // post thread end and vm death events to JVMTI,
3841 // stop signal thread
3842 // + Call JavaThread::exit(), it will:
3843 // > release JNI handle blocks, remove stack guard pages
3844 // > remove this thread from Threads list
3845 // <-- no more Java code from this thread after this point -->
3846 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3847 // the compiler threads at safepoint
3848 // <-- do not use anything that could get blocked by Safepoint -->
3849 // + Disable tracing at JNI/JVM barriers
3850 // + Set _vm_exited flag for threads that are still running native code
3851 // + Delete this thread
3852 // + Call exit_globals()
3853 // > deletes tty
3854 // > deletes PerfMemory resources
3855 // + Return to caller
3856
3857 bool Threads::destroy_vm() {
3858 JavaThread* thread = JavaThread::current();
3859
3860 #ifdef ASSERT
3861 _vm_complete = false;
3862 #endif
3863 // Wait until we are the last non-daemon thread to execute
3864 { MutexLocker nu(Threads_lock);
3865 while (Threads::number_of_non_daemon_threads() > 1)
3866 // This wait should make safepoint checks, wait without a timeout,
3867 // and wait as a suspend-equivalent condition.
3868 //
3869 // Note: If the FlatProfiler is running and this thread is waiting
3870 // for another non-daemon thread to finish, then the FlatProfiler
3871 // is waiting for the external suspend request on this thread to
3872 // complete. wait_for_ext_suspend_completion() will eventually
3873 // timeout, but that takes time. Making this wait a suspend-
3874 // equivalent condition solves that timeout problem.
3875 //
3876 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3877 Mutex::_as_suspend_equivalent_flag);
3878 }
3879
3880 // Hang forever on exit if we are reporting an error.
3881 if (ShowMessageBoxOnError && is_error_reported()) {
3882 os::infinite_sleep();
3883 }
3884 os::wait_for_keypress_at_exit();
3885
3886 // run Java level shutdown hooks
3887 thread->invoke_shutdown_hooks();
3888
3889 before_exit(thread);
3890
3891 thread->exit(true);
3892
3893 // Stop VM thread.
3894 {
3895 // 4945125 The vm thread comes to a safepoint during exit.
3896 // GC vm_operations can get caught at the safepoint, and the
3897 // heap is unparseable if they are caught. Grab the Heap_lock
3898 // to prevent this. The GC vm_operations will not be able to
3899 // queue until after the vm thread is dead. After this point,
3900 // we'll never emerge out of the safepoint before the VM exits.
3901
3902 MutexLocker ml(Heap_lock);
3903
3904 VMThread::wait_for_vm_thread_exit();
3905 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3906 VMThread::destroy();
3907 }
3908
3909 // clean up ideal graph printers
3910 #if defined(COMPILER2) && !defined(PRODUCT)
3911 IdealGraphPrinter::clean_up();
3912 #endif
3913
3914 // Now, all Java threads are gone except daemon threads. Daemon threads
3915 // running Java code or in VM are stopped by the Safepoint. However,
3916 // daemon threads executing native code are still running. But they
3917 // will be stopped at native=>Java/VM barriers. Note that we can't
3918 // simply kill or suspend them, as it is inherently deadlock-prone.
3919
3920 #ifndef PRODUCT
3921 // disable function tracing at JNI/JVM barriers
3922 TraceJNICalls = false;
3923 TraceJVMCalls = false;
3924 TraceRuntimeCalls = false;
3925 #endif
3926
3927 VM_Exit::set_vm_exited();
3928
3929 notify_vm_shutdown();
3930
3931 delete thread;
3932
3933 // exit_globals() will delete tty
3934 exit_globals();
3935
3936 return true;
3937 }
3938
3939
3940 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3941 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3942 return is_supported_jni_version(version);
3943 }
3944
3945
3946 jboolean Threads::is_supported_jni_version(jint version) {
3947 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3948 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3949 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3950 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3951 return JNI_FALSE;
3952 }
3953
3954
3955 void Threads::add(JavaThread* p, bool force_daemon) {
3956 // The threads lock must be owned at this point
3957 assert_locked_or_safepoint(Threads_lock);
3958
3959 // See the comment for this method in thread.hpp for its purpose and
3960 // why it is called here.
3961 p->initialize_queues();
3962 p->set_next(_thread_list);
3963 _thread_list = p;
3964 _number_of_threads++;
3965 oop threadObj = p->threadObj();
3966 bool daemon = true;
3967 // Bootstrapping problem: threadObj can be null for initial
3968 // JavaThread (or for threads attached via JNI)
3969 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3970 _number_of_non_daemon_threads++;
3971 daemon = false;
3972 }
3973
3974 ThreadService::add_thread(p, daemon);
3975
3976 // Possible GC point.
3977 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
3978 }
3979
3980 void Threads::remove(JavaThread* p) {
3981 // Extra scope needed for Thread_lock, so we can check
3982 // that we do not remove thread without safepoint code notice
3983 { MutexLocker ml(Threads_lock);
3984
3985 assert(includes(p), "p must be present");
3986
3987 JavaThread* current = _thread_list;
3988 JavaThread* prev = NULL;
3989
3990 while (current != p) {
3991 prev = current;
3992 current = current->next();
3993 }
3994
3995 if (prev) {
3996 prev->set_next(current->next());
3997 } else {
3998 _thread_list = p->next();
3999 }
4000 _number_of_threads--;
4001 oop threadObj = p->threadObj();
4002 bool daemon = true;
4003 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4004 _number_of_non_daemon_threads--;
4005 daemon = false;
4006
4007 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4008 // on destroy_vm will wake up.
4009 if (number_of_non_daemon_threads() == 1) {
4010 Threads_lock->notify_all();
4011 }
4012 }
4013 ThreadService::remove_thread(p, daemon);
4014
4015 // Make sure that safepoint code disregard this thread. This is needed since
4016 // the thread might mess around with locks after this point. This can cause it
4017 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4018 // of this thread since it is removed from the queue.
4019 p->set_terminated_value();
4020 } // unlock Threads_lock
4021
4022 // Since Events::log uses a lock, we grab it outside the Threads_lock
4023 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4024 }
4025
4026 // Threads_lock must be held when this is called (or must be called during a safepoint)
4027 bool Threads::includes(JavaThread* p) {
4028 assert(Threads_lock->is_locked(), "sanity check");
4029 ALL_JAVA_THREADS(q) {
4030 if (q == p) {
4031 return true;
4032 }
4033 }
4034 return false;
4035 }
4036
4037 // Operations on the Threads list for GC. These are not explicitly locked,
4038 // but the garbage collector must provide a safe context for them to run.
4039 // In particular, these things should never be called when the Threads_lock
4040 // is held by some other thread. (Note: the Safepoint abstraction also
4041 // uses the Threads_lock to guarantee this property. It also makes sure that
4042 // all threads gets blocked when exiting or starting).
4043
4044 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4045 ALL_JAVA_THREADS(p) {
4046 p->oops_do(f, cld_f, cf);
4047 }
4048 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4049 }
4050
4051 void Threads::change_thread_claim_parity() {
4052 // Set the new claim parity.
4053 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4054 "Not in range.");
4055 _thread_claim_parity++;
4056 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4057 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4058 "Not in range.");
4059 }
4060
4061 #ifdef ASSERT
4062 void Threads::assert_all_threads_claimed() {
4063 ALL_JAVA_THREADS(p) {
4064 const int thread_parity = p->oops_do_parity();
4065 assert((thread_parity == _thread_claim_parity),
4066 err_msg("Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity));
4067 }
4068 }
4069 #endif // ASSERT
4070
4071 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4072 int cp = Threads::thread_claim_parity();
4073 ALL_JAVA_THREADS(p) {
4074 if (p->claim_oops_do(is_par, cp)) {
4075 p->oops_do(f, cld_f, cf);
4076 }
4077 }
4078 VMThread* vmt = VMThread::vm_thread();
4079 if (vmt->claim_oops_do(is_par, cp)) {
4080 vmt->oops_do(f, cld_f, cf);
4081 }
4082 }
4083
4084 #if INCLUDE_ALL_GCS
4085 // Used by ParallelScavenge
4086 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4087 ALL_JAVA_THREADS(p) {
4088 q->enqueue(new ThreadRootsTask(p));
4089 }
4090 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4091 }
4092
4093 // Used by Parallel Old
4094 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4095 ALL_JAVA_THREADS(p) {
4096 q->enqueue(new ThreadRootsMarkingTask(p));
4097 }
4098 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4099 }
4100 #endif // INCLUDE_ALL_GCS
4101
4102 void Threads::nmethods_do(CodeBlobClosure* cf) {
4103 ALL_JAVA_THREADS(p) {
4104 p->nmethods_do(cf);
4105 }
4106 VMThread::vm_thread()->nmethods_do(cf);
4107 }
4108
4109 void Threads::metadata_do(void f(Metadata*)) {
4110 ALL_JAVA_THREADS(p) {
4111 p->metadata_do(f);
4112 }
4113 }
4114
4115 class ThreadHandlesClosure : public ThreadClosure {
4116 void (*_f)(Metadata*);
4117 public:
4118 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4119 virtual void do_thread(Thread* thread) {
4120 thread->metadata_handles_do(_f);
4121 }
4122 };
4123
4124 void Threads::metadata_handles_do(void f(Metadata*)) {
4125 // Only walk the Handles in Thread.
4126 ThreadHandlesClosure handles_closure(f);
4127 threads_do(&handles_closure);
4128 }
4129
4130 void Threads::deoptimized_wrt_marked_nmethods() {
4131 ALL_JAVA_THREADS(p) {
4132 p->deoptimized_wrt_marked_nmethods();
4133 }
4134 }
4135
4136
4137 // Get count Java threads that are waiting to enter the specified monitor.
4138 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4139 address monitor,
4140 bool doLock) {
4141 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4142 "must grab Threads_lock or be at safepoint");
4143 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4144
4145 int i = 0;
4146 {
4147 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4148 ALL_JAVA_THREADS(p) {
4149 if (p->is_Compiler_thread()) continue;
4150
4151 address pending = (address)p->current_pending_monitor();
4152 if (pending == monitor) { // found a match
4153 if (i < count) result->append(p); // save the first count matches
4154 i++;
4155 }
4156 }
4157 }
4158 return result;
4159 }
4160
4161
4162 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4163 bool doLock) {
4164 assert(doLock ||
4165 Threads_lock->owned_by_self() ||
4166 SafepointSynchronize::is_at_safepoint(),
4167 "must grab Threads_lock or be at safepoint");
4168
4169 // NULL owner means not locked so we can skip the search
4170 if (owner == NULL) return NULL;
4171
4172 {
4173 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4174 ALL_JAVA_THREADS(p) {
4175 // first, see if owner is the address of a Java thread
4176 if (owner == (address)p) return p;
4177 }
4178 }
4179 // Cannot assert on lack of success here since this function may be
4180 // used by code that is trying to report useful problem information
4181 // like deadlock detection.
4182 if (UseHeavyMonitors) return NULL;
4183
4184 // If we didn't find a matching Java thread and we didn't force use of
4185 // heavyweight monitors, then the owner is the stack address of the
4186 // Lock Word in the owning Java thread's stack.
4187 //
4188 JavaThread* the_owner = NULL;
4189 {
4190 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4191 ALL_JAVA_THREADS(q) {
4192 if (q->is_lock_owned(owner)) {
4193 the_owner = q;
4194 break;
4195 }
4196 }
4197 }
4198 // cannot assert on lack of success here; see above comment
4199 return the_owner;
4200 }
4201
4202 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4203 void Threads::print_on(outputStream* st, bool print_stacks,
4204 bool internal_format, bool print_concurrent_locks) {
4205 char buf[32];
4206 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4207
4208 st->print_cr("Full thread dump %s (%s %s):",
4209 Abstract_VM_Version::vm_name(),
4210 Abstract_VM_Version::vm_release(),
4211 Abstract_VM_Version::vm_info_string());
4212 st->cr();
4213
4214 #if INCLUDE_ALL_GCS
4215 // Dump concurrent locks
4216 ConcurrentLocksDump concurrent_locks;
4217 if (print_concurrent_locks) {
4218 concurrent_locks.dump_at_safepoint();
4219 }
4220 #endif // INCLUDE_ALL_GCS
4221
4222 ALL_JAVA_THREADS(p) {
4223 ResourceMark rm;
4224 p->print_on(st);
4225 if (print_stacks) {
4226 if (internal_format) {
4227 p->trace_stack();
4228 } else {
4229 p->print_stack_on(st);
4230 }
4231 }
4232 st->cr();
4233 #if INCLUDE_ALL_GCS
4234 if (print_concurrent_locks) {
4235 concurrent_locks.print_locks_on(p, st);
4236 }
4237 #endif // INCLUDE_ALL_GCS
4238 }
4239
4240 VMThread::vm_thread()->print_on(st);
4241 st->cr();
4242 Universe::heap()->print_gc_threads_on(st);
4243 WatcherThread* wt = WatcherThread::watcher_thread();
4244 if (wt != NULL) {
4245 wt->print_on(st);
4246 st->cr();
4247 }
4248 CompileBroker::print_compiler_threads_on(st);
4249 st->flush();
4250 }
4251
4252 // Threads::print_on_error() is called by fatal error handler. It's possible
4253 // that VM is not at safepoint and/or current thread is inside signal handler.
4254 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4255 // memory (even in resource area), it might deadlock the error handler.
4256 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4257 int buflen) {
4258 bool found_current = false;
4259 st->print_cr("Java Threads: ( => current thread )");
4260 ALL_JAVA_THREADS(thread) {
4261 bool is_current = (current == thread);
4262 found_current = found_current || is_current;
4263
4264 st->print("%s", is_current ? "=>" : " ");
4265
4266 st->print(PTR_FORMAT, thread);
4267 st->print(" ");
4268 thread->print_on_error(st, buf, buflen);
4269 st->cr();
4270 }
4271 st->cr();
4272
4273 st->print_cr("Other Threads:");
4274 if (VMThread::vm_thread()) {
4275 bool is_current = (current == VMThread::vm_thread());
4276 found_current = found_current || is_current;
4277 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4278
4279 st->print(PTR_FORMAT, VMThread::vm_thread());
4280 st->print(" ");
4281 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4282 st->cr();
4283 }
4284 WatcherThread* wt = WatcherThread::watcher_thread();
4285 if (wt != NULL) {
4286 bool is_current = (current == wt);
4287 found_current = found_current || is_current;
4288 st->print("%s", is_current ? "=>" : " ");
4289
4290 st->print(PTR_FORMAT, wt);
4291 st->print(" ");
4292 wt->print_on_error(st, buf, buflen);
4293 st->cr();
4294 }
4295 if (!found_current) {
4296 st->cr();
4297 st->print("=>" PTR_FORMAT " (exited) ", current);
4298 current->print_on_error(st, buf, buflen);
4299 st->cr();
4300 }
4301 }
4302
4303 // Internal SpinLock and Mutex
4304 // Based on ParkEvent
4305
4306 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4307 //
4308 // We employ SpinLocks _only for low-contention, fixed-length
4309 // short-duration critical sections where we're concerned
4310 // about native mutex_t or HotSpot Mutex:: latency.
4311 // The mux construct provides a spin-then-block mutual exclusion
4312 // mechanism.
4313 //
4314 // Testing has shown that contention on the ListLock guarding gFreeList
4315 // is common. If we implement ListLock as a simple SpinLock it's common
4316 // for the JVM to devolve to yielding with little progress. This is true
4317 // despite the fact that the critical sections protected by ListLock are
4318 // extremely short.
4319 //
4320 // TODO-FIXME: ListLock should be of type SpinLock.
4321 // We should make this a 1st-class type, integrated into the lock
4322 // hierarchy as leaf-locks. Critically, the SpinLock structure
4323 // should have sufficient padding to avoid false-sharing and excessive
4324 // cache-coherency traffic.
4325
4326
4327 typedef volatile int SpinLockT;
4328
4329 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4330 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4331 return; // normal fast-path return
4332 }
4333
4334 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4335 TEVENT(SpinAcquire - ctx);
4336 int ctr = 0;
4337 int Yields = 0;
4338 for (;;) {
4339 while (*adr != 0) {
4340 ++ctr;
4341 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4342 if (Yields > 5) {
4343 os::naked_short_sleep(1);
4344 } else {
4345 os::naked_yield();
4346 ++Yields;
4347 }
4348 } else {
4349 SpinPause();
4350 }
4351 }
4352 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4353 }
4354 }
4355
4356 void Thread::SpinRelease(volatile int * adr) {
4357 assert(*adr != 0, "invariant");
4358 OrderAccess::fence(); // guarantee at least release consistency.
4359 // Roach-motel semantics.
4360 // It's safe if subsequent LDs and STs float "up" into the critical section,
4361 // but prior LDs and STs within the critical section can't be allowed
4362 // to reorder or float past the ST that releases the lock.
4363 // Loads and stores in the critical section - which appear in program
4364 // order before the store that releases the lock - must also appear
4365 // before the store that releases the lock in memory visibility order.
4366 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4367 // the ST of 0 into the lock-word which releases the lock, so fence
4368 // more than covers this on all platforms.
4369 *adr = 0;
4370 }
4371
4372 // muxAcquire and muxRelease:
4373 //
4374 // * muxAcquire and muxRelease support a single-word lock-word construct.
4375 // The LSB of the word is set IFF the lock is held.
4376 // The remainder of the word points to the head of a singly-linked list
4377 // of threads blocked on the lock.
4378 //
4379 // * The current implementation of muxAcquire-muxRelease uses its own
4380 // dedicated Thread._MuxEvent instance. If we're interested in
4381 // minimizing the peak number of extant ParkEvent instances then
4382 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4383 // as certain invariants were satisfied. Specifically, care would need
4384 // to be taken with regards to consuming unpark() "permits".
4385 // A safe rule of thumb is that a thread would never call muxAcquire()
4386 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4387 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4388 // consume an unpark() permit intended for monitorenter, for instance.
4389 // One way around this would be to widen the restricted-range semaphore
4390 // implemented in park(). Another alternative would be to provide
4391 // multiple instances of the PlatformEvent() for each thread. One
4392 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4393 //
4394 // * Usage:
4395 // -- Only as leaf locks
4396 // -- for short-term locking only as muxAcquire does not perform
4397 // thread state transitions.
4398 //
4399 // Alternatives:
4400 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4401 // but with parking or spin-then-park instead of pure spinning.
4402 // * Use Taura-Oyama-Yonenzawa locks.
4403 // * It's possible to construct a 1-0 lock if we encode the lockword as
4404 // (List,LockByte). Acquire will CAS the full lockword while Release
4405 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4406 // acquiring threads use timers (ParkTimed) to detect and recover from
4407 // the stranding window. Thread/Node structures must be aligned on 256-byte
4408 // boundaries by using placement-new.
4409 // * Augment MCS with advisory back-link fields maintained with CAS().
4410 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4411 // The validity of the backlinks must be ratified before we trust the value.
4412 // If the backlinks are invalid the exiting thread must back-track through the
4413 // the forward links, which are always trustworthy.
4414 // * Add a successor indication. The LockWord is currently encoded as
4415 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4416 // to provide the usual futile-wakeup optimization.
4417 // See RTStt for details.
4418 // * Consider schedctl.sc_nopreempt to cover the critical section.
4419 //
4420
4421
4422 typedef volatile intptr_t MutexT; // Mux Lock-word
4423 enum MuxBits { LOCKBIT = 1 };
4424
4425 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4426 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4427 if (w == 0) return;
4428 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4429 return;
4430 }
4431
4432 TEVENT(muxAcquire - Contention);
4433 ParkEvent * const Self = Thread::current()->_MuxEvent;
4434 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4435 for (;;) {
4436 int its = (os::is_MP() ? 100 : 0) + 1;
4437
4438 // Optional spin phase: spin-then-park strategy
4439 while (--its >= 0) {
4440 w = *Lock;
4441 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4442 return;
4443 }
4444 }
4445
4446 Self->reset();
4447 Self->OnList = intptr_t(Lock);
4448 // The following fence() isn't _strictly necessary as the subsequent
4449 // CAS() both serializes execution and ratifies the fetched *Lock value.
4450 OrderAccess::fence();
4451 for (;;) {
4452 w = *Lock;
4453 if ((w & LOCKBIT) == 0) {
4454 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4455 Self->OnList = 0; // hygiene - allows stronger asserts
4456 return;
4457 }
4458 continue; // Interference -- *Lock changed -- Just retry
4459 }
4460 assert(w & LOCKBIT, "invariant");
4461 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4462 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4463 }
4464
4465 while (Self->OnList != 0) {
4466 Self->park();
4467 }
4468 }
4469 }
4470
4471 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4472 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4473 if (w == 0) return;
4474 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4475 return;
4476 }
4477
4478 TEVENT(muxAcquire - Contention);
4479 ParkEvent * ReleaseAfter = NULL;
4480 if (ev == NULL) {
4481 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4482 }
4483 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4484 for (;;) {
4485 guarantee(ev->OnList == 0, "invariant");
4486 int its = (os::is_MP() ? 100 : 0) + 1;
4487
4488 // Optional spin phase: spin-then-park strategy
4489 while (--its >= 0) {
4490 w = *Lock;
4491 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4492 if (ReleaseAfter != NULL) {
4493 ParkEvent::Release(ReleaseAfter);
4494 }
4495 return;
4496 }
4497 }
4498
4499 ev->reset();
4500 ev->OnList = intptr_t(Lock);
4501 // The following fence() isn't _strictly necessary as the subsequent
4502 // CAS() both serializes execution and ratifies the fetched *Lock value.
4503 OrderAccess::fence();
4504 for (;;) {
4505 w = *Lock;
4506 if ((w & LOCKBIT) == 0) {
4507 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4508 ev->OnList = 0;
4509 // We call ::Release while holding the outer lock, thus
4510 // artificially lengthening the critical section.
4511 // Consider deferring the ::Release() until the subsequent unlock(),
4512 // after we've dropped the outer lock.
4513 if (ReleaseAfter != NULL) {
4514 ParkEvent::Release(ReleaseAfter);
4515 }
4516 return;
4517 }
4518 continue; // Interference -- *Lock changed -- Just retry
4519 }
4520 assert(w & LOCKBIT, "invariant");
4521 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4522 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4523 }
4524
4525 while (ev->OnList != 0) {
4526 ev->park();
4527 }
4528 }
4529 }
4530
4531 // Release() must extract a successor from the list and then wake that thread.
4532 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4533 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4534 // Release() would :
4535 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4536 // (B) Extract a successor from the private list "in-hand"
4537 // (C) attempt to CAS() the residual back into *Lock over null.
4538 // If there were any newly arrived threads and the CAS() would fail.
4539 // In that case Release() would detach the RATs, re-merge the list in-hand
4540 // with the RATs and repeat as needed. Alternately, Release() might
4541 // detach and extract a successor, but then pass the residual list to the wakee.
4542 // The wakee would be responsible for reattaching and remerging before it
4543 // competed for the lock.
4544 //
4545 // Both "pop" and DMR are immune from ABA corruption -- there can be
4546 // multiple concurrent pushers, but only one popper or detacher.
4547 // This implementation pops from the head of the list. This is unfair,
4548 // but tends to provide excellent throughput as hot threads remain hot.
4549 // (We wake recently run threads first).
4550 //
4551 // All paths through muxRelease() will execute a CAS.
4552 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4553 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4554 // executed within the critical section are complete and globally visible before the
4555 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4556 void Thread::muxRelease(volatile intptr_t * Lock) {
4557 for (;;) {
4558 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4559 assert(w & LOCKBIT, "invariant");
4560 if (w == LOCKBIT) return;
4561 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4562 assert(List != NULL, "invariant");
4563 assert(List->OnList == intptr_t(Lock), "invariant");
4564 ParkEvent * const nxt = List->ListNext;
4565 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4566
4567 // The following CAS() releases the lock and pops the head element.
4568 // The CAS() also ratifies the previously fetched lock-word value.
4569 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4570 continue;
4571 }
4572 List->OnList = 0;
4573 OrderAccess::fence();
4574 List->unpark();
4575 return;
4576 }
4577 }
4578
4579
4580 void Threads::verify() {
4581 ALL_JAVA_THREADS(p) {
4582 p->verify();
4583 }
4584 VMThread* thread = VMThread::vm_thread();
4585 if (thread != NULL) thread->verify();
4586 }