1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/codeCacheExtensions.hpp"
32 #include "code/scopeDesc.hpp"
33 #include "compiler/compileBroker.hpp"
34 #include "gc/shared/gcLocker.inline.hpp"
35 #include "gc/shared/workgroup.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "interpreter/linkResolver.hpp"
38 #include "interpreter/oopMapCache.hpp"
39 #include "jvmtifiles/jvmtiEnv.hpp"
40 #include "memory/metaspaceShared.hpp"
41 #include "memory/oopFactory.hpp"
42 #include "memory/universe.inline.hpp"
43 #include "oops/instanceKlass.hpp"
44 #include "oops/objArrayOop.hpp"
45 #include "oops/oop.inline.hpp"
46 #include "oops/symbol.hpp"
47 #include "oops/verifyOopClosure.hpp"
48 #include "prims/jvm_misc.hpp"
49 #include "prims/jvmtiExport.hpp"
50 #include "prims/jvmtiThreadState.hpp"
51 #include "prims/privilegedStack.hpp"
52 #include "runtime/arguments.hpp"
53 #include "runtime/atomic.inline.hpp"
54 #include "runtime/biasedLocking.hpp"
55 #include "runtime/deoptimization.hpp"
56 #include "runtime/fprofiler.hpp"
57 #include "runtime/frame.inline.hpp"
58 #include "runtime/globals.hpp"
59 #include "runtime/init.hpp"
60 #include "runtime/interfaceSupport.hpp"
61 #include "runtime/java.hpp"
62 #include "runtime/javaCalls.hpp"
63 #include "runtime/jniPeriodicChecker.hpp"
64 #include "runtime/memprofiler.hpp"
65 #include "runtime/mutexLocker.hpp"
66 #include "runtime/objectMonitor.hpp"
67 #include "runtime/orderAccess.inline.hpp"
68 #include "runtime/osThread.hpp"
69 #include "runtime/safepoint.hpp"
70 #include "runtime/sharedRuntime.hpp"
71 #include "runtime/statSampler.hpp"
72 #include "runtime/stubRoutines.hpp"
73 #include "runtime/sweeper.hpp"
74 #include "runtime/task.hpp"
75 #include "runtime/thread.inline.hpp"
76 #include "runtime/threadCritical.hpp"
77 #include "runtime/threadLocalStorage.hpp"
78 #include "runtime/vframe.hpp"
79 #include "runtime/vframeArray.hpp"
80 #include "runtime/vframe_hp.hpp"
81 #include "runtime/vmThread.hpp"
82 #include "runtime/vm_operations.hpp"
83 #include "runtime/vm_version.hpp"
84 #include "services/attachListener.hpp"
85 #include "services/management.hpp"
86 #include "services/memTracker.hpp"
87 #include "services/threadService.hpp"
88 #include "trace/traceMacros.hpp"
89 #include "trace/tracing.hpp"
90 #include "utilities/defaultStream.hpp"
91 #include "utilities/dtrace.hpp"
92 #include "utilities/events.hpp"
93 #include "utilities/macros.hpp"
94 #include "utilities/preserveException.hpp"
95 #if INCLUDE_ALL_GCS
96 #include "gc/cms/concurrentMarkSweepThread.hpp"
97 #include "gc/g1/concurrentMarkThread.inline.hpp"
98 #include "gc/parallel/pcTasks.hpp"
99 #endif // INCLUDE_ALL_GCS
100 #ifdef COMPILER1
101 #include "c1/c1_Compiler.hpp"
102 #endif
103 #ifdef COMPILER2
104 #include "opto/c2compiler.hpp"
105 #include "opto/idealGraphPrinter.hpp"
106 #endif
107 #if INCLUDE_RTM_OPT
108 #include "runtime/rtmLocking.hpp"
109 #endif
110
111 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
112
113 #ifdef DTRACE_ENABLED
114
115 // Only bother with this argument setup if dtrace is available
116
117 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
118 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
119
120 #define DTRACE_THREAD_PROBE(probe, javathread) \
121 { \
122 ResourceMark rm(this); \
123 int len = 0; \
124 const char* name = (javathread)->get_thread_name(); \
125 len = strlen(name); \
126 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
127 (char *) name, len, \
128 java_lang_Thread::thread_id((javathread)->threadObj()), \
129 (uintptr_t) (javathread)->osthread()->thread_id(), \
130 java_lang_Thread::is_daemon((javathread)->threadObj())); \
131 }
132
133 #else // ndef DTRACE_ENABLED
134
135 #define DTRACE_THREAD_PROBE(probe, javathread)
136
137 #endif // ndef DTRACE_ENABLED
138
139
140 // Class hierarchy
141 // - Thread
142 // - VMThread
143 // - WatcherThread
144 // - ConcurrentMarkSweepThread
145 // - JavaThread
146 // - CompilerThread
147
148 // ======= Thread ========
149 // Support for forcing alignment of thread objects for biased locking
150 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
151 if (UseBiasedLocking) {
152 const int alignment = markOopDesc::biased_lock_alignment;
153 size_t aligned_size = size + (alignment - sizeof(intptr_t));
154 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
155 : AllocateHeap(aligned_size, flags, CURRENT_PC,
156 AllocFailStrategy::RETURN_NULL);
157 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
158 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
159 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
160 "JavaThread alignment code overflowed allocated storage");
161 if (TraceBiasedLocking) {
162 if (aligned_addr != real_malloc_addr) {
163 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
164 real_malloc_addr, aligned_addr);
165 }
166 }
167 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
168 return aligned_addr;
169 } else {
170 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
171 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
172 }
173 }
174
175 void Thread::operator delete(void* p) {
176 if (UseBiasedLocking) {
177 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
178 FreeHeap(real_malloc_addr);
179 } else {
180 FreeHeap(p);
181 }
182 }
183
184
185 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
186 // JavaThread
187
188
189 Thread::Thread() {
190 // stack and get_thread
191 set_stack_base(NULL);
192 set_stack_size(0);
193 set_self_raw_id(0);
194 set_lgrp_id(-1);
195 DEBUG_ONLY(clear_suspendible_thread();)
196
197 // allocated data structures
198 set_osthread(NULL);
199 set_resource_area(new (mtThread)ResourceArea());
200 DEBUG_ONLY(_current_resource_mark = NULL;)
201 set_handle_area(new (mtThread) HandleArea(NULL));
202 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
203 set_active_handles(NULL);
204 set_free_handle_block(NULL);
205 set_last_handle_mark(NULL);
206
207 // This initial value ==> never claimed.
208 _oops_do_parity = 0;
209
210 // the handle mark links itself to last_handle_mark
211 new HandleMark(this);
212
213 // plain initialization
214 debug_only(_owned_locks = NULL;)
215 debug_only(_allow_allocation_count = 0;)
216 NOT_PRODUCT(_allow_safepoint_count = 0;)
217 NOT_PRODUCT(_skip_gcalot = false;)
218 _jvmti_env_iteration_count = 0;
219 set_allocated_bytes(0);
220 _vm_operation_started_count = 0;
221 _vm_operation_completed_count = 0;
222 _current_pending_monitor = NULL;
223 _current_pending_monitor_is_from_java = true;
224 _current_waiting_monitor = NULL;
225 _num_nested_signal = 0;
226 omFreeList = NULL;
227 omFreeCount = 0;
228 omFreeProvision = 32;
229 omInUseList = NULL;
230 omInUseCount = 0;
231
232 #ifdef ASSERT
233 _visited_for_critical_count = false;
234 #endif
235
236 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
237 Monitor::_safepoint_check_sometimes);
238 _suspend_flags = 0;
239
240 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
241 _hashStateX = os::random();
242 _hashStateY = 842502087;
243 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
244 _hashStateW = 273326509;
245
246 _OnTrap = 0;
247 _schedctl = NULL;
248 _Stalled = 0;
249 _TypeTag = 0x2BAD;
250
251 // Many of the following fields are effectively final - immutable
252 // Note that nascent threads can't use the Native Monitor-Mutex
253 // construct until the _MutexEvent is initialized ...
254 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
255 // we might instead use a stack of ParkEvents that we could provision on-demand.
256 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
257 // and ::Release()
258 _ParkEvent = ParkEvent::Allocate(this);
259 _SleepEvent = ParkEvent::Allocate(this);
260 _MutexEvent = ParkEvent::Allocate(this);
261 _MuxEvent = ParkEvent::Allocate(this);
262
263 #ifdef CHECK_UNHANDLED_OOPS
264 if (CheckUnhandledOops) {
265 _unhandled_oops = new UnhandledOops(this);
266 }
267 #endif // CHECK_UNHANDLED_OOPS
268 #ifdef ASSERT
269 if (UseBiasedLocking) {
270 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
271 assert(this == _real_malloc_address ||
272 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
273 "bug in forced alignment of thread objects");
274 }
275 #endif // ASSERT
276 }
277
278 // Non-inlined version to be used where thread.inline.hpp shouldn't be included.
279 Thread* Thread::current_noinline() {
280 return Thread::current();
281 }
282
283 void Thread::initialize_thread_local_storage() {
284 // Note: Make sure this method only calls
285 // non-blocking operations. Otherwise, it might not work
286 // with the thread-startup/safepoint interaction.
287
288 // During Java thread startup, safepoint code should allow this
289 // method to complete because it may need to allocate memory to
290 // store information for the new thread.
291
292 // initialize structure dependent on thread local storage
293 ThreadLocalStorage::set_thread(this);
294 }
295
296 void Thread::record_stack_base_and_size() {
297 set_stack_base(os::current_stack_base());
298 set_stack_size(os::current_stack_size());
299 if (is_Java_thread()) {
300 ((JavaThread*) this)->set_stack_overflow_limit();
301 }
302 // CR 7190089: on Solaris, primordial thread's stack is adjusted
303 // in initialize_thread(). Without the adjustment, stack size is
304 // incorrect if stack is set to unlimited (ulimit -s unlimited).
305 // So far, only Solaris has real implementation of initialize_thread().
306 //
307 // set up any platform-specific state.
308 os::initialize_thread(this);
309
310 #if INCLUDE_NMT
311 // record thread's native stack, stack grows downward
312 address stack_low_addr = stack_base() - stack_size();
313 MemTracker::record_thread_stack(stack_low_addr, stack_size());
314 #endif // INCLUDE_NMT
315 }
316
317
318 Thread::~Thread() {
319 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
320 ObjectSynchronizer::omFlush(this);
321
322 EVENT_THREAD_DESTRUCT(this);
323
324 // stack_base can be NULL if the thread is never started or exited before
325 // record_stack_base_and_size called. Although, we would like to ensure
326 // that all started threads do call record_stack_base_and_size(), there is
327 // not proper way to enforce that.
328 #if INCLUDE_NMT
329 if (_stack_base != NULL) {
330 address low_stack_addr = stack_base() - stack_size();
331 MemTracker::release_thread_stack(low_stack_addr, stack_size());
332 #ifdef ASSERT
333 set_stack_base(NULL);
334 #endif
335 }
336 #endif // INCLUDE_NMT
337
338 // deallocate data structures
339 delete resource_area();
340 // since the handle marks are using the handle area, we have to deallocated the root
341 // handle mark before deallocating the thread's handle area,
342 assert(last_handle_mark() != NULL, "check we have an element");
343 delete last_handle_mark();
344 assert(last_handle_mark() == NULL, "check we have reached the end");
345
346 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
347 // We NULL out the fields for good hygiene.
348 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
349 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
350 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
351 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
352
353 delete handle_area();
354 delete metadata_handles();
355
356 // osthread() can be NULL, if creation of thread failed.
357 if (osthread() != NULL) os::free_thread(osthread());
358
359 delete _SR_lock;
360
361 // clear thread local storage if the Thread is deleting itself
362 if (this == Thread::current()) {
363 ThreadLocalStorage::set_thread(NULL);
364 } else {
365 // In the case where we're not the current thread, invalidate all the
366 // caches in case some code tries to get the current thread or the
367 // thread that was destroyed, and gets stale information.
368 ThreadLocalStorage::invalidate_all();
369 }
370 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
371 }
372
373 // NOTE: dummy function for assertion purpose.
374 void Thread::run() {
375 ShouldNotReachHere();
376 }
377
378 #ifdef ASSERT
379 // Private method to check for dangling thread pointer
380 void check_for_dangling_thread_pointer(Thread *thread) {
381 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
382 "possibility of dangling Thread pointer");
383 }
384 #endif
385
386 ThreadPriority Thread::get_priority(const Thread* const thread) {
387 ThreadPriority priority;
388 // Can return an error!
389 (void)os::get_priority(thread, priority);
390 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
391 return priority;
392 }
393
394 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
395 debug_only(check_for_dangling_thread_pointer(thread);)
396 // Can return an error!
397 (void)os::set_priority(thread, priority);
398 }
399
400
401 void Thread::start(Thread* thread) {
402 // Start is different from resume in that its safety is guaranteed by context or
403 // being called from a Java method synchronized on the Thread object.
404 if (!DisableStartThread) {
405 if (thread->is_Java_thread()) {
406 // Initialize the thread state to RUNNABLE before starting this thread.
407 // Can not set it after the thread started because we do not know the
408 // exact thread state at that time. It could be in MONITOR_WAIT or
409 // in SLEEPING or some other state.
410 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
411 java_lang_Thread::RUNNABLE);
412 }
413 os::start_thread(thread);
414 }
415 }
416
417 // Enqueue a VM_Operation to do the job for us - sometime later
418 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
419 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
420 VMThread::execute(vm_stop);
421 }
422
423
424 // Check if an external suspend request has completed (or has been
425 // cancelled). Returns true if the thread is externally suspended and
426 // false otherwise.
427 //
428 // The bits parameter returns information about the code path through
429 // the routine. Useful for debugging:
430 //
431 // set in is_ext_suspend_completed():
432 // 0x00000001 - routine was entered
433 // 0x00000010 - routine return false at end
434 // 0x00000100 - thread exited (return false)
435 // 0x00000200 - suspend request cancelled (return false)
436 // 0x00000400 - thread suspended (return true)
437 // 0x00001000 - thread is in a suspend equivalent state (return true)
438 // 0x00002000 - thread is native and walkable (return true)
439 // 0x00004000 - thread is native_trans and walkable (needed retry)
440 //
441 // set in wait_for_ext_suspend_completion():
442 // 0x00010000 - routine was entered
443 // 0x00020000 - suspend request cancelled before loop (return false)
444 // 0x00040000 - thread suspended before loop (return true)
445 // 0x00080000 - suspend request cancelled in loop (return false)
446 // 0x00100000 - thread suspended in loop (return true)
447 // 0x00200000 - suspend not completed during retry loop (return false)
448
449 // Helper class for tracing suspend wait debug bits.
450 //
451 // 0x00000100 indicates that the target thread exited before it could
452 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
453 // 0x00080000 each indicate a cancelled suspend request so they don't
454 // count as wait failures either.
455 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
456
457 class TraceSuspendDebugBits : public StackObj {
458 private:
459 JavaThread * jt;
460 bool is_wait;
461 bool called_by_wait; // meaningful when !is_wait
462 uint32_t * bits;
463
464 public:
465 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
466 uint32_t *_bits) {
467 jt = _jt;
468 is_wait = _is_wait;
469 called_by_wait = _called_by_wait;
470 bits = _bits;
471 }
472
473 ~TraceSuspendDebugBits() {
474 if (!is_wait) {
475 #if 1
476 // By default, don't trace bits for is_ext_suspend_completed() calls.
477 // That trace is very chatty.
478 return;
479 #else
480 if (!called_by_wait) {
481 // If tracing for is_ext_suspend_completed() is enabled, then only
482 // trace calls to it from wait_for_ext_suspend_completion()
483 return;
484 }
485 #endif
486 }
487
488 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
489 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
490 MutexLocker ml(Threads_lock); // needed for get_thread_name()
491 ResourceMark rm;
492
493 tty->print_cr(
494 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
495 jt->get_thread_name(), *bits);
496
497 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
498 }
499 }
500 }
501 };
502 #undef DEBUG_FALSE_BITS
503
504
505 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
506 uint32_t *bits) {
507 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
508
509 bool did_trans_retry = false; // only do thread_in_native_trans retry once
510 bool do_trans_retry; // flag to force the retry
511
512 *bits |= 0x00000001;
513
514 do {
515 do_trans_retry = false;
516
517 if (is_exiting()) {
518 // Thread is in the process of exiting. This is always checked
519 // first to reduce the risk of dereferencing a freed JavaThread.
520 *bits |= 0x00000100;
521 return false;
522 }
523
524 if (!is_external_suspend()) {
525 // Suspend request is cancelled. This is always checked before
526 // is_ext_suspended() to reduce the risk of a rogue resume
527 // confusing the thread that made the suspend request.
528 *bits |= 0x00000200;
529 return false;
530 }
531
532 if (is_ext_suspended()) {
533 // thread is suspended
534 *bits |= 0x00000400;
535 return true;
536 }
537
538 // Now that we no longer do hard suspends of threads running
539 // native code, the target thread can be changing thread state
540 // while we are in this routine:
541 //
542 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
543 //
544 // We save a copy of the thread state as observed at this moment
545 // and make our decision about suspend completeness based on the
546 // copy. This closes the race where the thread state is seen as
547 // _thread_in_native_trans in the if-thread_blocked check, but is
548 // seen as _thread_blocked in if-thread_in_native_trans check.
549 JavaThreadState save_state = thread_state();
550
551 if (save_state == _thread_blocked && is_suspend_equivalent()) {
552 // If the thread's state is _thread_blocked and this blocking
553 // condition is known to be equivalent to a suspend, then we can
554 // consider the thread to be externally suspended. This means that
555 // the code that sets _thread_blocked has been modified to do
556 // self-suspension if the blocking condition releases. We also
557 // used to check for CONDVAR_WAIT here, but that is now covered by
558 // the _thread_blocked with self-suspension check.
559 //
560 // Return true since we wouldn't be here unless there was still an
561 // external suspend request.
562 *bits |= 0x00001000;
563 return true;
564 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
565 // Threads running native code will self-suspend on native==>VM/Java
566 // transitions. If its stack is walkable (should always be the case
567 // unless this function is called before the actual java_suspend()
568 // call), then the wait is done.
569 *bits |= 0x00002000;
570 return true;
571 } else if (!called_by_wait && !did_trans_retry &&
572 save_state == _thread_in_native_trans &&
573 frame_anchor()->walkable()) {
574 // The thread is transitioning from thread_in_native to another
575 // thread state. check_safepoint_and_suspend_for_native_trans()
576 // will force the thread to self-suspend. If it hasn't gotten
577 // there yet we may have caught the thread in-between the native
578 // code check above and the self-suspend. Lucky us. If we were
579 // called by wait_for_ext_suspend_completion(), then it
580 // will be doing the retries so we don't have to.
581 //
582 // Since we use the saved thread state in the if-statement above,
583 // there is a chance that the thread has already transitioned to
584 // _thread_blocked by the time we get here. In that case, we will
585 // make a single unnecessary pass through the logic below. This
586 // doesn't hurt anything since we still do the trans retry.
587
588 *bits |= 0x00004000;
589
590 // Once the thread leaves thread_in_native_trans for another
591 // thread state, we break out of this retry loop. We shouldn't
592 // need this flag to prevent us from getting back here, but
593 // sometimes paranoia is good.
594 did_trans_retry = true;
595
596 // We wait for the thread to transition to a more usable state.
597 for (int i = 1; i <= SuspendRetryCount; i++) {
598 // We used to do an "os::yield_all(i)" call here with the intention
599 // that yielding would increase on each retry. However, the parameter
600 // is ignored on Linux which means the yield didn't scale up. Waiting
601 // on the SR_lock below provides a much more predictable scale up for
602 // the delay. It also provides a simple/direct point to check for any
603 // safepoint requests from the VMThread
604
605 // temporarily drops SR_lock while doing wait with safepoint check
606 // (if we're a JavaThread - the WatcherThread can also call this)
607 // and increase delay with each retry
608 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
609
610 // check the actual thread state instead of what we saved above
611 if (thread_state() != _thread_in_native_trans) {
612 // the thread has transitioned to another thread state so
613 // try all the checks (except this one) one more time.
614 do_trans_retry = true;
615 break;
616 }
617 } // end retry loop
618
619
620 }
621 } while (do_trans_retry);
622
623 *bits |= 0x00000010;
624 return false;
625 }
626
627 // Wait for an external suspend request to complete (or be cancelled).
628 // Returns true if the thread is externally suspended and false otherwise.
629 //
630 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
631 uint32_t *bits) {
632 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
633 false /* !called_by_wait */, bits);
634
635 // local flag copies to minimize SR_lock hold time
636 bool is_suspended;
637 bool pending;
638 uint32_t reset_bits;
639
640 // set a marker so is_ext_suspend_completed() knows we are the caller
641 *bits |= 0x00010000;
642
643 // We use reset_bits to reinitialize the bits value at the top of
644 // each retry loop. This allows the caller to make use of any
645 // unused bits for their own marking purposes.
646 reset_bits = *bits;
647
648 {
649 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
650 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
651 delay, bits);
652 pending = is_external_suspend();
653 }
654 // must release SR_lock to allow suspension to complete
655
656 if (!pending) {
657 // A cancelled suspend request is the only false return from
658 // is_ext_suspend_completed() that keeps us from entering the
659 // retry loop.
660 *bits |= 0x00020000;
661 return false;
662 }
663
664 if (is_suspended) {
665 *bits |= 0x00040000;
666 return true;
667 }
668
669 for (int i = 1; i <= retries; i++) {
670 *bits = reset_bits; // reinit to only track last retry
671
672 // We used to do an "os::yield_all(i)" call here with the intention
673 // that yielding would increase on each retry. However, the parameter
674 // is ignored on Linux which means the yield didn't scale up. Waiting
675 // on the SR_lock below provides a much more predictable scale up for
676 // the delay. It also provides a simple/direct point to check for any
677 // safepoint requests from the VMThread
678
679 {
680 MutexLocker ml(SR_lock());
681 // wait with safepoint check (if we're a JavaThread - the WatcherThread
682 // can also call this) and increase delay with each retry
683 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
684
685 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
686 delay, bits);
687
688 // It is possible for the external suspend request to be cancelled
689 // (by a resume) before the actual suspend operation is completed.
690 // Refresh our local copy to see if we still need to wait.
691 pending = is_external_suspend();
692 }
693
694 if (!pending) {
695 // A cancelled suspend request is the only false return from
696 // is_ext_suspend_completed() that keeps us from staying in the
697 // retry loop.
698 *bits |= 0x00080000;
699 return false;
700 }
701
702 if (is_suspended) {
703 *bits |= 0x00100000;
704 return true;
705 }
706 } // end retry loop
707
708 // thread did not suspend after all our retries
709 *bits |= 0x00200000;
710 return false;
711 }
712
713 #ifndef PRODUCT
714 void JavaThread::record_jump(address target, address instr, const char* file,
715 int line) {
716
717 // This should not need to be atomic as the only way for simultaneous
718 // updates is via interrupts. Even then this should be rare or non-existent
719 // and we don't care that much anyway.
720
721 int index = _jmp_ring_index;
722 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
723 _jmp_ring[index]._target = (intptr_t) target;
724 _jmp_ring[index]._instruction = (intptr_t) instr;
725 _jmp_ring[index]._file = file;
726 _jmp_ring[index]._line = line;
727 }
728 #endif // PRODUCT
729
730 // Called by flat profiler
731 // Callers have already called wait_for_ext_suspend_completion
732 // The assertion for that is currently too complex to put here:
733 bool JavaThread::profile_last_Java_frame(frame* _fr) {
734 bool gotframe = false;
735 // self suspension saves needed state.
736 if (has_last_Java_frame() && _anchor.walkable()) {
737 *_fr = pd_last_frame();
738 gotframe = true;
739 }
740 return gotframe;
741 }
742
743 void Thread::interrupt(Thread* thread) {
744 debug_only(check_for_dangling_thread_pointer(thread);)
745 os::interrupt(thread);
746 }
747
748 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
749 debug_only(check_for_dangling_thread_pointer(thread);)
750 // Note: If clear_interrupted==false, this simply fetches and
751 // returns the value of the field osthread()->interrupted().
752 return os::is_interrupted(thread, clear_interrupted);
753 }
754
755
756 // GC Support
757 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
758 jint thread_parity = _oops_do_parity;
759 if (thread_parity != strong_roots_parity) {
760 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
761 if (res == thread_parity) {
762 return true;
763 } else {
764 guarantee(res == strong_roots_parity, "Or else what?");
765 return false;
766 }
767 }
768 return false;
769 }
770
771 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
772 active_handles()->oops_do(f);
773 // Do oop for ThreadShadow
774 f->do_oop((oop*)&_pending_exception);
775 handle_area()->oops_do(f);
776 }
777
778 void Thread::nmethods_do(CodeBlobClosure* cf) {
779 // no nmethods in a generic thread...
780 }
781
782 void Thread::metadata_handles_do(void f(Metadata*)) {
783 // Only walk the Handles in Thread.
784 if (metadata_handles() != NULL) {
785 for (int i = 0; i< metadata_handles()->length(); i++) {
786 f(metadata_handles()->at(i));
787 }
788 }
789 }
790
791 void Thread::print_on(outputStream* st) const {
792 // get_priority assumes osthread initialized
793 if (osthread() != NULL) {
794 int os_prio;
795 if (os::get_native_priority(this, &os_prio) == OS_OK) {
796 st->print("os_prio=%d ", os_prio);
797 }
798 st->print("tid=" INTPTR_FORMAT " ", this);
799 ext().print_on(st);
800 osthread()->print_on(st);
801 }
802 debug_only(if (WizardMode) print_owned_locks_on(st);)
803 }
804
805 // Thread::print_on_error() is called by fatal error handler. Don't use
806 // any lock or allocate memory.
807 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
808 if (is_VM_thread()) st->print("VMThread");
809 else if (is_Compiler_thread()) st->print("CompilerThread");
810 else if (is_Java_thread()) st->print("JavaThread");
811 else if (is_GC_task_thread()) st->print("GCTaskThread");
812 else if (is_Watcher_thread()) st->print("WatcherThread");
813 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
814 else st->print("Thread");
815
816 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
817 _stack_base - _stack_size, _stack_base);
818
819 if (osthread()) {
820 st->print(" [id=%d]", osthread()->thread_id());
821 }
822 }
823
824 #ifdef ASSERT
825 void Thread::print_owned_locks_on(outputStream* st) const {
826 Monitor *cur = _owned_locks;
827 if (cur == NULL) {
828 st->print(" (no locks) ");
829 } else {
830 st->print_cr(" Locks owned:");
831 while (cur) {
832 cur->print_on(st);
833 cur = cur->next();
834 }
835 }
836 }
837
838 static int ref_use_count = 0;
839
840 bool Thread::owns_locks_but_compiled_lock() const {
841 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
842 if (cur != Compile_lock) return true;
843 }
844 return false;
845 }
846
847
848 #endif
849
850 #ifndef PRODUCT
851
852 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
853 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
854 // no threads which allow_vm_block's are held
855 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
856 // Check if current thread is allowed to block at a safepoint
857 if (!(_allow_safepoint_count == 0)) {
858 fatal("Possible safepoint reached by thread that does not allow it");
859 }
860 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
861 fatal("LEAF method calling lock?");
862 }
863
864 #ifdef ASSERT
865 if (potential_vm_operation && is_Java_thread()
866 && !Universe::is_bootstrapping()) {
867 // Make sure we do not hold any locks that the VM thread also uses.
868 // This could potentially lead to deadlocks
869 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
870 // Threads_lock is special, since the safepoint synchronization will not start before this is
871 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
872 // since it is used to transfer control between JavaThreads and the VMThread
873 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
874 if ((cur->allow_vm_block() &&
875 cur != Threads_lock &&
876 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
877 cur != VMOperationRequest_lock &&
878 cur != VMOperationQueue_lock) ||
879 cur->rank() == Mutex::special) {
880 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
881 }
882 }
883 }
884
885 if (GCALotAtAllSafepoints) {
886 // We could enter a safepoint here and thus have a gc
887 InterfaceSupport::check_gc_alot();
888 }
889 #endif
890 }
891 #endif
892
893 bool Thread::is_in_stack(address adr) const {
894 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
895 address end = os::current_stack_pointer();
896 // Allow non Java threads to call this without stack_base
897 if (_stack_base == NULL) return true;
898 if (stack_base() >= adr && adr >= end) return true;
899
900 return false;
901 }
902
903
904 bool Thread::is_in_usable_stack(address adr) const {
905 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
906 size_t usable_stack_size = _stack_size - stack_guard_size;
907
908 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
909 }
910
911
912 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
913 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
914 // used for compilation in the future. If that change is made, the need for these methods
915 // should be revisited, and they should be removed if possible.
916
917 bool Thread::is_lock_owned(address adr) const {
918 return on_local_stack(adr);
919 }
920
921 bool Thread::set_as_starting_thread() {
922 // NOTE: this must be called inside the main thread.
923 return os::create_main_thread((JavaThread*)this);
924 }
925
926 static void initialize_class(Symbol* class_name, TRAPS) {
927 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
928 InstanceKlass::cast(klass)->initialize(CHECK);
929 }
930
931
932 // Creates the initial ThreadGroup
933 static Handle create_initial_thread_group(TRAPS) {
934 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
935 instanceKlassHandle klass (THREAD, k);
936
937 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
938 {
939 JavaValue result(T_VOID);
940 JavaCalls::call_special(&result,
941 system_instance,
942 klass,
943 vmSymbols::object_initializer_name(),
944 vmSymbols::void_method_signature(),
945 CHECK_NH);
946 }
947 Universe::set_system_thread_group(system_instance());
948
949 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
950 {
951 JavaValue result(T_VOID);
952 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
953 JavaCalls::call_special(&result,
954 main_instance,
955 klass,
956 vmSymbols::object_initializer_name(),
957 vmSymbols::threadgroup_string_void_signature(),
958 system_instance,
959 string,
960 CHECK_NH);
961 }
962 return main_instance;
963 }
964
965 // Creates the initial Thread
966 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
967 TRAPS) {
968 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
969 instanceKlassHandle klass (THREAD, k);
970 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
971
972 java_lang_Thread::set_thread(thread_oop(), thread);
973 java_lang_Thread::set_priority(thread_oop(), NormPriority);
974 thread->set_threadObj(thread_oop());
975
976 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
977
978 JavaValue result(T_VOID);
979 JavaCalls::call_special(&result, thread_oop,
980 klass,
981 vmSymbols::object_initializer_name(),
982 vmSymbols::threadgroup_string_void_signature(),
983 thread_group,
984 string,
985 CHECK_NULL);
986 return thread_oop();
987 }
988
989 static void call_initializeSystemClass(TRAPS) {
990 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
991 instanceKlassHandle klass (THREAD, k);
992
993 JavaValue result(T_VOID);
994 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
995 vmSymbols::void_method_signature(), CHECK);
996 }
997
998 char java_runtime_name[128] = "";
999 char java_runtime_version[128] = "";
1000
1001 // extract the JRE name from sun.misc.Version.java_runtime_name
1002 static const char* get_java_runtime_name(TRAPS) {
1003 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1004 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1005 fieldDescriptor fd;
1006 bool found = k != NULL &&
1007 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1008 vmSymbols::string_signature(), &fd);
1009 if (found) {
1010 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1011 if (name_oop == NULL) {
1012 return NULL;
1013 }
1014 const char* name = java_lang_String::as_utf8_string(name_oop,
1015 java_runtime_name,
1016 sizeof(java_runtime_name));
1017 return name;
1018 } else {
1019 return NULL;
1020 }
1021 }
1022
1023 // extract the JRE version from sun.misc.Version.java_runtime_version
1024 static const char* get_java_runtime_version(TRAPS) {
1025 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1026 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1027 fieldDescriptor fd;
1028 bool found = k != NULL &&
1029 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1030 vmSymbols::string_signature(), &fd);
1031 if (found) {
1032 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1033 if (name_oop == NULL) {
1034 return NULL;
1035 }
1036 const char* name = java_lang_String::as_utf8_string(name_oop,
1037 java_runtime_version,
1038 sizeof(java_runtime_version));
1039 return name;
1040 } else {
1041 return NULL;
1042 }
1043 }
1044
1045 // General purpose hook into Java code, run once when the VM is initialized.
1046 // The Java library method itself may be changed independently from the VM.
1047 static void call_postVMInitHook(TRAPS) {
1048 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1049 instanceKlassHandle klass (THREAD, k);
1050 if (klass.not_null()) {
1051 JavaValue result(T_VOID);
1052 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1053 vmSymbols::void_method_signature(),
1054 CHECK);
1055 }
1056 }
1057
1058 static void reset_vm_info_property(TRAPS) {
1059 // the vm info string
1060 ResourceMark rm(THREAD);
1061 const char *vm_info = VM_Version::vm_info_string();
1062
1063 // java.lang.System class
1064 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1065 instanceKlassHandle klass (THREAD, k);
1066
1067 // setProperty arguments
1068 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1069 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1070
1071 // return value
1072 JavaValue r(T_OBJECT);
1073
1074 // public static String setProperty(String key, String value);
1075 JavaCalls::call_static(&r,
1076 klass,
1077 vmSymbols::setProperty_name(),
1078 vmSymbols::string_string_string_signature(),
1079 key_str,
1080 value_str,
1081 CHECK);
1082 }
1083
1084
1085 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1086 bool daemon, TRAPS) {
1087 assert(thread_group.not_null(), "thread group should be specified");
1088 assert(threadObj() == NULL, "should only create Java thread object once");
1089
1090 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1091 instanceKlassHandle klass (THREAD, k);
1092 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1093
1094 java_lang_Thread::set_thread(thread_oop(), this);
1095 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1096 set_threadObj(thread_oop());
1097
1098 JavaValue result(T_VOID);
1099 if (thread_name != NULL) {
1100 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1101 // Thread gets assigned specified name and null target
1102 JavaCalls::call_special(&result,
1103 thread_oop,
1104 klass,
1105 vmSymbols::object_initializer_name(),
1106 vmSymbols::threadgroup_string_void_signature(),
1107 thread_group, // Argument 1
1108 name, // Argument 2
1109 THREAD);
1110 } else {
1111 // Thread gets assigned name "Thread-nnn" and null target
1112 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1113 JavaCalls::call_special(&result,
1114 thread_oop,
1115 klass,
1116 vmSymbols::object_initializer_name(),
1117 vmSymbols::threadgroup_runnable_void_signature(),
1118 thread_group, // Argument 1
1119 Handle(), // Argument 2
1120 THREAD);
1121 }
1122
1123
1124 if (daemon) {
1125 java_lang_Thread::set_daemon(thread_oop());
1126 }
1127
1128 if (HAS_PENDING_EXCEPTION) {
1129 return;
1130 }
1131
1132 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1133 Handle threadObj(THREAD, this->threadObj());
1134
1135 JavaCalls::call_special(&result,
1136 thread_group,
1137 group,
1138 vmSymbols::add_method_name(),
1139 vmSymbols::thread_void_signature(),
1140 threadObj, // Arg 1
1141 THREAD);
1142 }
1143
1144 // NamedThread -- non-JavaThread subclasses with multiple
1145 // uniquely named instances should derive from this.
1146 NamedThread::NamedThread() : Thread() {
1147 _name = NULL;
1148 _processed_thread = NULL;
1149 }
1150
1151 NamedThread::~NamedThread() {
1152 if (_name != NULL) {
1153 FREE_C_HEAP_ARRAY(char, _name);
1154 _name = NULL;
1155 }
1156 }
1157
1158 void NamedThread::set_name(const char* format, ...) {
1159 guarantee(_name == NULL, "Only get to set name once.");
1160 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1161 guarantee(_name != NULL, "alloc failure");
1162 va_list ap;
1163 va_start(ap, format);
1164 jio_vsnprintf(_name, max_name_len, format, ap);
1165 va_end(ap);
1166 }
1167
1168 void NamedThread::initialize_named_thread() {
1169 set_native_thread_name(name());
1170 }
1171
1172 void NamedThread::print_on(outputStream* st) const {
1173 st->print("\"%s\" ", name());
1174 Thread::print_on(st);
1175 st->cr();
1176 }
1177
1178
1179 // ======= WatcherThread ========
1180
1181 // The watcher thread exists to simulate timer interrupts. It should
1182 // be replaced by an abstraction over whatever native support for
1183 // timer interrupts exists on the platform.
1184
1185 WatcherThread* WatcherThread::_watcher_thread = NULL;
1186 bool WatcherThread::_startable = false;
1187 volatile bool WatcherThread::_should_terminate = false;
1188
1189 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1190 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1191 if (os::create_thread(this, os::watcher_thread)) {
1192 _watcher_thread = this;
1193
1194 // Set the watcher thread to the highest OS priority which should not be
1195 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1196 // is created. The only normal thread using this priority is the reference
1197 // handler thread, which runs for very short intervals only.
1198 // If the VMThread's priority is not lower than the WatcherThread profiling
1199 // will be inaccurate.
1200 os::set_priority(this, MaxPriority);
1201 if (!DisableStartThread) {
1202 os::start_thread(this);
1203 }
1204 }
1205 }
1206
1207 int WatcherThread::sleep() const {
1208 // The WatcherThread does not participate in the safepoint protocol
1209 // for the PeriodicTask_lock because it is not a JavaThread.
1210 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1211
1212 if (_should_terminate) {
1213 // check for termination before we do any housekeeping or wait
1214 return 0; // we did not sleep.
1215 }
1216
1217 // remaining will be zero if there are no tasks,
1218 // causing the WatcherThread to sleep until a task is
1219 // enrolled
1220 int remaining = PeriodicTask::time_to_wait();
1221 int time_slept = 0;
1222
1223 // we expect this to timeout - we only ever get unparked when
1224 // we should terminate or when a new task has been enrolled
1225 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1226
1227 jlong time_before_loop = os::javaTimeNanos();
1228
1229 while (true) {
1230 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1231 remaining);
1232 jlong now = os::javaTimeNanos();
1233
1234 if (remaining == 0) {
1235 // if we didn't have any tasks we could have waited for a long time
1236 // consider the time_slept zero and reset time_before_loop
1237 time_slept = 0;
1238 time_before_loop = now;
1239 } else {
1240 // need to recalculate since we might have new tasks in _tasks
1241 time_slept = (int) ((now - time_before_loop) / 1000000);
1242 }
1243
1244 // Change to task list or spurious wakeup of some kind
1245 if (timedout || _should_terminate) {
1246 break;
1247 }
1248
1249 remaining = PeriodicTask::time_to_wait();
1250 if (remaining == 0) {
1251 // Last task was just disenrolled so loop around and wait until
1252 // another task gets enrolled
1253 continue;
1254 }
1255
1256 remaining -= time_slept;
1257 if (remaining <= 0) {
1258 break;
1259 }
1260 }
1261
1262 return time_slept;
1263 }
1264
1265 void WatcherThread::run() {
1266 assert(this == watcher_thread(), "just checking");
1267
1268 this->record_stack_base_and_size();
1269 this->initialize_thread_local_storage();
1270 this->set_native_thread_name(this->name());
1271 this->set_active_handles(JNIHandleBlock::allocate_block());
1272 while (true) {
1273 assert(watcher_thread() == Thread::current(), "thread consistency check");
1274 assert(watcher_thread() == this, "thread consistency check");
1275
1276 // Calculate how long it'll be until the next PeriodicTask work
1277 // should be done, and sleep that amount of time.
1278 int time_waited = sleep();
1279
1280 if (is_error_reported()) {
1281 // A fatal error has happened, the error handler(VMError::report_and_die)
1282 // should abort JVM after creating an error log file. However in some
1283 // rare cases, the error handler itself might deadlock. Here we try to
1284 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1285 //
1286 // This code is in WatcherThread because WatcherThread wakes up
1287 // periodically so the fatal error handler doesn't need to do anything;
1288 // also because the WatcherThread is less likely to crash than other
1289 // threads.
1290
1291 for (;;) {
1292 if (!ShowMessageBoxOnError
1293 && (OnError == NULL || OnError[0] == '\0')
1294 && Arguments::abort_hook() == NULL) {
1295 os::sleep(this, ErrorLogTimeout * 60 * 1000, false);
1296 fdStream err(defaultStream::output_fd());
1297 err.print_raw_cr("# [ timer expired, abort... ]");
1298 // skip atexit/vm_exit/vm_abort hooks
1299 os::die();
1300 }
1301
1302 // Wake up 5 seconds later, the fatal handler may reset OnError or
1303 // ShowMessageBoxOnError when it is ready to abort.
1304 os::sleep(this, 5 * 1000, false);
1305 }
1306 }
1307
1308 if (_should_terminate) {
1309 // check for termination before posting the next tick
1310 break;
1311 }
1312
1313 PeriodicTask::real_time_tick(time_waited);
1314 }
1315
1316 // Signal that it is terminated
1317 {
1318 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1319 _watcher_thread = NULL;
1320 Terminator_lock->notify();
1321 }
1322
1323 // Thread destructor usually does this..
1324 ThreadLocalStorage::set_thread(NULL);
1325 }
1326
1327 void WatcherThread::start() {
1328 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1329
1330 if (watcher_thread() == NULL && _startable) {
1331 _should_terminate = false;
1332 // Create the single instance of WatcherThread
1333 new WatcherThread();
1334 }
1335 }
1336
1337 void WatcherThread::make_startable() {
1338 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1339 _startable = true;
1340 }
1341
1342 void WatcherThread::stop() {
1343 {
1344 // Follow normal safepoint aware lock enter protocol since the
1345 // WatcherThread is stopped by another JavaThread.
1346 MutexLocker ml(PeriodicTask_lock);
1347 _should_terminate = true;
1348
1349 WatcherThread* watcher = watcher_thread();
1350 if (watcher != NULL) {
1351 // unpark the WatcherThread so it can see that it should terminate
1352 watcher->unpark();
1353 }
1354 }
1355
1356 MutexLocker mu(Terminator_lock);
1357
1358 while (watcher_thread() != NULL) {
1359 // This wait should make safepoint checks, wait without a timeout,
1360 // and wait as a suspend-equivalent condition.
1361 //
1362 // Note: If the FlatProfiler is running, then this thread is waiting
1363 // for the WatcherThread to terminate and the WatcherThread, via the
1364 // FlatProfiler task, is waiting for the external suspend request on
1365 // this thread to complete. wait_for_ext_suspend_completion() will
1366 // eventually timeout, but that takes time. Making this wait a
1367 // suspend-equivalent condition solves that timeout problem.
1368 //
1369 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1370 Mutex::_as_suspend_equivalent_flag);
1371 }
1372 }
1373
1374 void WatcherThread::unpark() {
1375 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1376 PeriodicTask_lock->notify();
1377 }
1378
1379 void WatcherThread::print_on(outputStream* st) const {
1380 st->print("\"%s\" ", name());
1381 Thread::print_on(st);
1382 st->cr();
1383 }
1384
1385 // ======= JavaThread ========
1386
1387 // A JavaThread is a normal Java thread
1388
1389 void JavaThread::initialize() {
1390 // Initialize fields
1391
1392 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1393 set_claimed_par_id(UINT_MAX);
1394
1395 set_saved_exception_pc(NULL);
1396 set_threadObj(NULL);
1397 _anchor.clear();
1398 set_entry_point(NULL);
1399 set_jni_functions(jni_functions());
1400 set_callee_target(NULL);
1401 set_vm_result(NULL);
1402 set_vm_result_2(NULL);
1403 set_vframe_array_head(NULL);
1404 set_vframe_array_last(NULL);
1405 set_deferred_locals(NULL);
1406 set_deopt_mark(NULL);
1407 set_deopt_nmethod(NULL);
1408 clear_must_deopt_id();
1409 set_monitor_chunks(NULL);
1410 set_next(NULL);
1411 set_thread_state(_thread_new);
1412 _terminated = _not_terminated;
1413 _privileged_stack_top = NULL;
1414 _array_for_gc = NULL;
1415 _suspend_equivalent = false;
1416 _in_deopt_handler = 0;
1417 _doing_unsafe_access = false;
1418 _stack_guard_state = stack_guard_unused;
1419 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1420 _exception_pc = 0;
1421 _exception_handler_pc = 0;
1422 _is_method_handle_return = 0;
1423 _jvmti_thread_state= NULL;
1424 _should_post_on_exceptions_flag = JNI_FALSE;
1425 _jvmti_get_loaded_classes_closure = NULL;
1426 _interp_only_mode = 0;
1427 _special_runtime_exit_condition = _no_async_condition;
1428 _pending_async_exception = NULL;
1429 _thread_stat = NULL;
1430 _thread_stat = new ThreadStatistics();
1431 _blocked_on_compilation = false;
1432 _jni_active_critical = 0;
1433 _pending_jni_exception_check_fn = NULL;
1434 _do_not_unlock_if_synchronized = false;
1435 _cached_monitor_info = NULL;
1436 _parker = Parker::Allocate(this);
1437
1438 #ifndef PRODUCT
1439 _jmp_ring_index = 0;
1440 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1441 record_jump(NULL, NULL, NULL, 0);
1442 }
1443 #endif // PRODUCT
1444
1445 set_thread_profiler(NULL);
1446 if (FlatProfiler::is_active()) {
1447 // This is where we would decide to either give each thread it's own profiler
1448 // or use one global one from FlatProfiler,
1449 // or up to some count of the number of profiled threads, etc.
1450 ThreadProfiler* pp = new ThreadProfiler();
1451 pp->engage();
1452 set_thread_profiler(pp);
1453 }
1454
1455 // Setup safepoint state info for this thread
1456 ThreadSafepointState::create(this);
1457
1458 debug_only(_java_call_counter = 0);
1459
1460 // JVMTI PopFrame support
1461 _popframe_condition = popframe_inactive;
1462 _popframe_preserved_args = NULL;
1463 _popframe_preserved_args_size = 0;
1464 _frames_to_pop_failed_realloc = 0;
1465
1466 pd_initialize();
1467 }
1468
1469 #if INCLUDE_ALL_GCS
1470 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1471 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1472 #endif // INCLUDE_ALL_GCS
1473
1474 JavaThread::JavaThread(bool is_attaching_via_jni) :
1475 Thread()
1476 #if INCLUDE_ALL_GCS
1477 , _satb_mark_queue(&_satb_mark_queue_set),
1478 _dirty_card_queue(&_dirty_card_queue_set)
1479 #endif // INCLUDE_ALL_GCS
1480 {
1481 initialize();
1482 if (is_attaching_via_jni) {
1483 _jni_attach_state = _attaching_via_jni;
1484 } else {
1485 _jni_attach_state = _not_attaching_via_jni;
1486 }
1487 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1488 }
1489
1490 bool JavaThread::reguard_stack(address cur_sp) {
1491 if (_stack_guard_state != stack_guard_yellow_disabled) {
1492 return true; // Stack already guarded or guard pages not needed.
1493 }
1494
1495 if (register_stack_overflow()) {
1496 // For those architectures which have separate register and
1497 // memory stacks, we must check the register stack to see if
1498 // it has overflowed.
1499 return false;
1500 }
1501
1502 // Java code never executes within the yellow zone: the latter is only
1503 // there to provoke an exception during stack banging. If java code
1504 // is executing there, either StackShadowPages should be larger, or
1505 // some exception code in c1, c2 or the interpreter isn't unwinding
1506 // when it should.
1507 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1508
1509 enable_stack_yellow_zone();
1510 return true;
1511 }
1512
1513 bool JavaThread::reguard_stack(void) {
1514 return reguard_stack(os::current_stack_pointer());
1515 }
1516
1517
1518 void JavaThread::block_if_vm_exited() {
1519 if (_terminated == _vm_exited) {
1520 // _vm_exited is set at safepoint, and Threads_lock is never released
1521 // we will block here forever
1522 Threads_lock->lock_without_safepoint_check();
1523 ShouldNotReachHere();
1524 }
1525 }
1526
1527
1528 // Remove this ifdef when C1 is ported to the compiler interface.
1529 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1530 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1531
1532 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1533 Thread()
1534 #if INCLUDE_ALL_GCS
1535 , _satb_mark_queue(&_satb_mark_queue_set),
1536 _dirty_card_queue(&_dirty_card_queue_set)
1537 #endif // INCLUDE_ALL_GCS
1538 {
1539 initialize();
1540 _jni_attach_state = _not_attaching_via_jni;
1541 set_entry_point(entry_point);
1542 // Create the native thread itself.
1543 // %note runtime_23
1544 os::ThreadType thr_type = os::java_thread;
1545 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1546 os::java_thread;
1547 os::create_thread(this, thr_type, stack_sz);
1548 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1549 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1550 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1551 // the exception consists of creating the exception object & initializing it, initialization
1552 // will leave the VM via a JavaCall and then all locks must be unlocked).
1553 //
1554 // The thread is still suspended when we reach here. Thread must be explicit started
1555 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1556 // by calling Threads:add. The reason why this is not done here, is because the thread
1557 // object must be fully initialized (take a look at JVM_Start)
1558 }
1559
1560 JavaThread::~JavaThread() {
1561
1562 // JSR166 -- return the parker to the free list
1563 Parker::Release(_parker);
1564 _parker = NULL;
1565
1566 // Free any remaining previous UnrollBlock
1567 vframeArray* old_array = vframe_array_last();
1568
1569 if (old_array != NULL) {
1570 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1571 old_array->set_unroll_block(NULL);
1572 delete old_info;
1573 delete old_array;
1574 }
1575
1576 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1577 if (deferred != NULL) {
1578 // This can only happen if thread is destroyed before deoptimization occurs.
1579 assert(deferred->length() != 0, "empty array!");
1580 do {
1581 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1582 deferred->remove_at(0);
1583 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1584 delete dlv;
1585 } while (deferred->length() != 0);
1586 delete deferred;
1587 }
1588
1589 // All Java related clean up happens in exit
1590 ThreadSafepointState::destroy(this);
1591 if (_thread_profiler != NULL) delete _thread_profiler;
1592 if (_thread_stat != NULL) delete _thread_stat;
1593 }
1594
1595
1596 // The first routine called by a new Java thread
1597 void JavaThread::run() {
1598 // initialize thread-local alloc buffer related fields
1599 this->initialize_tlab();
1600
1601 // used to test validity of stack trace backs
1602 this->record_base_of_stack_pointer();
1603
1604 // Record real stack base and size.
1605 this->record_stack_base_and_size();
1606
1607 // Initialize thread local storage; set before calling MutexLocker
1608 this->initialize_thread_local_storage();
1609
1610 this->create_stack_guard_pages();
1611
1612 this->cache_global_variables();
1613
1614 // Thread is now sufficient initialized to be handled by the safepoint code as being
1615 // in the VM. Change thread state from _thread_new to _thread_in_vm
1616 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1617
1618 assert(JavaThread::current() == this, "sanity check");
1619 assert(!Thread::current()->owns_locks(), "sanity check");
1620
1621 DTRACE_THREAD_PROBE(start, this);
1622
1623 // This operation might block. We call that after all safepoint checks for a new thread has
1624 // been completed.
1625 this->set_active_handles(JNIHandleBlock::allocate_block());
1626
1627 if (JvmtiExport::should_post_thread_life()) {
1628 JvmtiExport::post_thread_start(this);
1629 }
1630
1631 EventThreadStart event;
1632 if (event.should_commit()) {
1633 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1634 event.commit();
1635 }
1636
1637 // We call another function to do the rest so we are sure that the stack addresses used
1638 // from there will be lower than the stack base just computed
1639 thread_main_inner();
1640
1641 // Note, thread is no longer valid at this point!
1642 }
1643
1644
1645 void JavaThread::thread_main_inner() {
1646 assert(JavaThread::current() == this, "sanity check");
1647 assert(this->threadObj() != NULL, "just checking");
1648
1649 // Execute thread entry point unless this thread has a pending exception
1650 // or has been stopped before starting.
1651 // Note: Due to JVM_StopThread we can have pending exceptions already!
1652 if (!this->has_pending_exception() &&
1653 !java_lang_Thread::is_stillborn(this->threadObj())) {
1654 {
1655 ResourceMark rm(this);
1656 this->set_native_thread_name(this->get_thread_name());
1657 }
1658 HandleMark hm(this);
1659 this->entry_point()(this, this);
1660 }
1661
1662 DTRACE_THREAD_PROBE(stop, this);
1663
1664 this->exit(false);
1665 delete this;
1666 }
1667
1668
1669 static void ensure_join(JavaThread* thread) {
1670 // We do not need to grap the Threads_lock, since we are operating on ourself.
1671 Handle threadObj(thread, thread->threadObj());
1672 assert(threadObj.not_null(), "java thread object must exist");
1673 ObjectLocker lock(threadObj, thread);
1674 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1675 thread->clear_pending_exception();
1676 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1677 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1678 // Clear the native thread instance - this makes isAlive return false and allows the join()
1679 // to complete once we've done the notify_all below
1680 java_lang_Thread::set_thread(threadObj(), NULL);
1681 lock.notify_all(thread);
1682 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1683 thread->clear_pending_exception();
1684 }
1685
1686
1687 // For any new cleanup additions, please check to see if they need to be applied to
1688 // cleanup_failed_attach_current_thread as well.
1689 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1690 assert(this == JavaThread::current(), "thread consistency check");
1691
1692 HandleMark hm(this);
1693 Handle uncaught_exception(this, this->pending_exception());
1694 this->clear_pending_exception();
1695 Handle threadObj(this, this->threadObj());
1696 assert(threadObj.not_null(), "Java thread object should be created");
1697
1698 if (get_thread_profiler() != NULL) {
1699 get_thread_profiler()->disengage();
1700 ResourceMark rm;
1701 get_thread_profiler()->print(get_thread_name());
1702 }
1703
1704
1705 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1706 {
1707 EXCEPTION_MARK;
1708
1709 CLEAR_PENDING_EXCEPTION;
1710 }
1711 if (!destroy_vm) {
1712 if (uncaught_exception.not_null()) {
1713 EXCEPTION_MARK;
1714 // Call method Thread.dispatchUncaughtException().
1715 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1716 JavaValue result(T_VOID);
1717 JavaCalls::call_virtual(&result,
1718 threadObj, thread_klass,
1719 vmSymbols::dispatchUncaughtException_name(),
1720 vmSymbols::throwable_void_signature(),
1721 uncaught_exception,
1722 THREAD);
1723 if (HAS_PENDING_EXCEPTION) {
1724 ResourceMark rm(this);
1725 jio_fprintf(defaultStream::error_stream(),
1726 "\nException: %s thrown from the UncaughtExceptionHandler"
1727 " in thread \"%s\"\n",
1728 pending_exception()->klass()->external_name(),
1729 get_thread_name());
1730 CLEAR_PENDING_EXCEPTION;
1731 }
1732 }
1733
1734 // Called before the java thread exit since we want to read info
1735 // from java_lang_Thread object
1736 EventThreadEnd event;
1737 if (event.should_commit()) {
1738 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1739 event.commit();
1740 }
1741
1742 // Call after last event on thread
1743 EVENT_THREAD_EXIT(this);
1744
1745 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1746 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1747 // is deprecated anyhow.
1748 if (!is_Compiler_thread()) {
1749 int count = 3;
1750 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1751 EXCEPTION_MARK;
1752 JavaValue result(T_VOID);
1753 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1754 JavaCalls::call_virtual(&result,
1755 threadObj, thread_klass,
1756 vmSymbols::exit_method_name(),
1757 vmSymbols::void_method_signature(),
1758 THREAD);
1759 CLEAR_PENDING_EXCEPTION;
1760 }
1761 }
1762 // notify JVMTI
1763 if (JvmtiExport::should_post_thread_life()) {
1764 JvmtiExport::post_thread_end(this);
1765 }
1766
1767 // We have notified the agents that we are exiting, before we go on,
1768 // we must check for a pending external suspend request and honor it
1769 // in order to not surprise the thread that made the suspend request.
1770 while (true) {
1771 {
1772 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1773 if (!is_external_suspend()) {
1774 set_terminated(_thread_exiting);
1775 ThreadService::current_thread_exiting(this);
1776 break;
1777 }
1778 // Implied else:
1779 // Things get a little tricky here. We have a pending external
1780 // suspend request, but we are holding the SR_lock so we
1781 // can't just self-suspend. So we temporarily drop the lock
1782 // and then self-suspend.
1783 }
1784
1785 ThreadBlockInVM tbivm(this);
1786 java_suspend_self();
1787
1788 // We're done with this suspend request, but we have to loop around
1789 // and check again. Eventually we will get SR_lock without a pending
1790 // external suspend request and will be able to mark ourselves as
1791 // exiting.
1792 }
1793 // no more external suspends are allowed at this point
1794 } else {
1795 // before_exit() has already posted JVMTI THREAD_END events
1796 }
1797
1798 // Notify waiters on thread object. This has to be done after exit() is called
1799 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1800 // group should have the destroyed bit set before waiters are notified).
1801 ensure_join(this);
1802 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1803
1804 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1805 // held by this thread must be released. The spec does not distinguish
1806 // between JNI-acquired and regular Java monitors. We can only see
1807 // regular Java monitors here if monitor enter-exit matching is broken.
1808 //
1809 // Optionally release any monitors for regular JavaThread exits. This
1810 // is provided as a work around for any bugs in monitor enter-exit
1811 // matching. This can be expensive so it is not enabled by default.
1812 // ObjectMonitor::Knob_ExitRelease is a superset of the
1813 // JNIDetachReleasesMonitors option.
1814 //
1815 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1816 // ObjectSynchronizer::release_monitors_owned_by_thread().
1817 if ((exit_type == jni_detach && JNIDetachReleasesMonitors) ||
1818 ObjectMonitor::Knob_ExitRelease) {
1819 // Sanity check even though JNI DetachCurrentThread() would have
1820 // returned JNI_ERR if there was a Java frame. JavaThread exit
1821 // should be done executing Java code by the time we get here.
1822 assert(!this->has_last_Java_frame(),
1823 "should not have a Java frame when detaching or exiting");
1824 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1825 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1826 }
1827
1828 // These things needs to be done while we are still a Java Thread. Make sure that thread
1829 // is in a consistent state, in case GC happens
1830 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1831
1832 if (active_handles() != NULL) {
1833 JNIHandleBlock* block = active_handles();
1834 set_active_handles(NULL);
1835 JNIHandleBlock::release_block(block);
1836 }
1837
1838 if (free_handle_block() != NULL) {
1839 JNIHandleBlock* block = free_handle_block();
1840 set_free_handle_block(NULL);
1841 JNIHandleBlock::release_block(block);
1842 }
1843
1844 // These have to be removed while this is still a valid thread.
1845 remove_stack_guard_pages();
1846
1847 if (UseTLAB) {
1848 tlab().make_parsable(true); // retire TLAB
1849 }
1850
1851 if (JvmtiEnv::environments_might_exist()) {
1852 JvmtiExport::cleanup_thread(this);
1853 }
1854
1855 // We must flush any deferred card marks before removing a thread from
1856 // the list of active threads.
1857 Universe::heap()->flush_deferred_store_barrier(this);
1858 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1859
1860 #if INCLUDE_ALL_GCS
1861 // We must flush the G1-related buffers before removing a thread
1862 // from the list of active threads. We must do this after any deferred
1863 // card marks have been flushed (above) so that any entries that are
1864 // added to the thread's dirty card queue as a result are not lost.
1865 if (UseG1GC) {
1866 flush_barrier_queues();
1867 }
1868 #endif // INCLUDE_ALL_GCS
1869
1870 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1871 Threads::remove(this);
1872 }
1873
1874 #if INCLUDE_ALL_GCS
1875 // Flush G1-related queues.
1876 void JavaThread::flush_barrier_queues() {
1877 satb_mark_queue().flush();
1878 dirty_card_queue().flush();
1879 }
1880
1881 void JavaThread::initialize_queues() {
1882 assert(!SafepointSynchronize::is_at_safepoint(),
1883 "we should not be at a safepoint");
1884
1885 ObjPtrQueue& satb_queue = satb_mark_queue();
1886 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1887 // The SATB queue should have been constructed with its active
1888 // field set to false.
1889 assert(!satb_queue.is_active(), "SATB queue should not be active");
1890 assert(satb_queue.is_empty(), "SATB queue should be empty");
1891 // If we are creating the thread during a marking cycle, we should
1892 // set the active field of the SATB queue to true.
1893 if (satb_queue_set.is_active()) {
1894 satb_queue.set_active(true);
1895 }
1896
1897 DirtyCardQueue& dirty_queue = dirty_card_queue();
1898 // The dirty card queue should have been constructed with its
1899 // active field set to true.
1900 assert(dirty_queue.is_active(), "dirty card queue should be active");
1901 }
1902 #endif // INCLUDE_ALL_GCS
1903
1904 void JavaThread::cleanup_failed_attach_current_thread() {
1905 if (get_thread_profiler() != NULL) {
1906 get_thread_profiler()->disengage();
1907 ResourceMark rm;
1908 get_thread_profiler()->print(get_thread_name());
1909 }
1910
1911 if (active_handles() != NULL) {
1912 JNIHandleBlock* block = active_handles();
1913 set_active_handles(NULL);
1914 JNIHandleBlock::release_block(block);
1915 }
1916
1917 if (free_handle_block() != NULL) {
1918 JNIHandleBlock* block = free_handle_block();
1919 set_free_handle_block(NULL);
1920 JNIHandleBlock::release_block(block);
1921 }
1922
1923 // These have to be removed while this is still a valid thread.
1924 remove_stack_guard_pages();
1925
1926 if (UseTLAB) {
1927 tlab().make_parsable(true); // retire TLAB, if any
1928 }
1929
1930 #if INCLUDE_ALL_GCS
1931 if (UseG1GC) {
1932 flush_barrier_queues();
1933 }
1934 #endif // INCLUDE_ALL_GCS
1935
1936 Threads::remove(this);
1937 delete this;
1938 }
1939
1940
1941
1942
1943 JavaThread* JavaThread::active() {
1944 Thread* thread = ThreadLocalStorage::thread();
1945 assert(thread != NULL, "just checking");
1946 if (thread->is_Java_thread()) {
1947 return (JavaThread*) thread;
1948 } else {
1949 assert(thread->is_VM_thread(), "this must be a vm thread");
1950 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1951 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1952 assert(ret->is_Java_thread(), "must be a Java thread");
1953 return ret;
1954 }
1955 }
1956
1957 bool JavaThread::is_lock_owned(address adr) const {
1958 if (Thread::is_lock_owned(adr)) return true;
1959
1960 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1961 if (chunk->contains(adr)) return true;
1962 }
1963
1964 return false;
1965 }
1966
1967
1968 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1969 chunk->set_next(monitor_chunks());
1970 set_monitor_chunks(chunk);
1971 }
1972
1973 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1974 guarantee(monitor_chunks() != NULL, "must be non empty");
1975 if (monitor_chunks() == chunk) {
1976 set_monitor_chunks(chunk->next());
1977 } else {
1978 MonitorChunk* prev = monitor_chunks();
1979 while (prev->next() != chunk) prev = prev->next();
1980 prev->set_next(chunk->next());
1981 }
1982 }
1983
1984 // JVM support.
1985
1986 // Note: this function shouldn't block if it's called in
1987 // _thread_in_native_trans state (such as from
1988 // check_special_condition_for_native_trans()).
1989 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1990
1991 if (has_last_Java_frame() && has_async_condition()) {
1992 // If we are at a polling page safepoint (not a poll return)
1993 // then we must defer async exception because live registers
1994 // will be clobbered by the exception path. Poll return is
1995 // ok because the call we a returning from already collides
1996 // with exception handling registers and so there is no issue.
1997 // (The exception handling path kills call result registers but
1998 // this is ok since the exception kills the result anyway).
1999
2000 if (is_at_poll_safepoint()) {
2001 // if the code we are returning to has deoptimized we must defer
2002 // the exception otherwise live registers get clobbered on the
2003 // exception path before deoptimization is able to retrieve them.
2004 //
2005 RegisterMap map(this, false);
2006 frame caller_fr = last_frame().sender(&map);
2007 assert(caller_fr.is_compiled_frame(), "what?");
2008 if (caller_fr.is_deoptimized_frame()) {
2009 if (TraceExceptions) {
2010 ResourceMark rm;
2011 tty->print_cr("deferred async exception at compiled safepoint");
2012 }
2013 return;
2014 }
2015 }
2016 }
2017
2018 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2019 if (condition == _no_async_condition) {
2020 // Conditions have changed since has_special_runtime_exit_condition()
2021 // was called:
2022 // - if we were here only because of an external suspend request,
2023 // then that was taken care of above (or cancelled) so we are done
2024 // - if we were here because of another async request, then it has
2025 // been cleared between the has_special_runtime_exit_condition()
2026 // and now so again we are done
2027 return;
2028 }
2029
2030 // Check for pending async. exception
2031 if (_pending_async_exception != NULL) {
2032 // Only overwrite an already pending exception, if it is not a threadDeath.
2033 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2034
2035 // We cannot call Exceptions::_throw(...) here because we cannot block
2036 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2037
2038 if (TraceExceptions) {
2039 ResourceMark rm;
2040 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2041 if (has_last_Java_frame()) {
2042 frame f = last_frame();
2043 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2044 }
2045 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2046 }
2047 _pending_async_exception = NULL;
2048 clear_has_async_exception();
2049 }
2050 }
2051
2052 if (check_unsafe_error &&
2053 condition == _async_unsafe_access_error && !has_pending_exception()) {
2054 condition = _no_async_condition; // done
2055 switch (thread_state()) {
2056 case _thread_in_vm: {
2057 JavaThread* THREAD = this;
2058 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2059 }
2060 case _thread_in_native: {
2061 ThreadInVMfromNative tiv(this);
2062 JavaThread* THREAD = this;
2063 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2064 }
2065 case _thread_in_Java: {
2066 ThreadInVMfromJava tiv(this);
2067 JavaThread* THREAD = this;
2068 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2069 }
2070 default:
2071 ShouldNotReachHere();
2072 }
2073 }
2074
2075 assert(condition == _no_async_condition || has_pending_exception() ||
2076 (!check_unsafe_error && condition == _async_unsafe_access_error),
2077 "must have handled the async condition, if no exception");
2078 }
2079
2080 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2081 //
2082 // Check for pending external suspend. Internal suspend requests do
2083 // not use handle_special_runtime_exit_condition().
2084 // If JNIEnv proxies are allowed, don't self-suspend if the target
2085 // thread is not the current thread. In older versions of jdbx, jdbx
2086 // threads could call into the VM with another thread's JNIEnv so we
2087 // can be here operating on behalf of a suspended thread (4432884).
2088 bool do_self_suspend = is_external_suspend_with_lock();
2089 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2090 //
2091 // Because thread is external suspended the safepoint code will count
2092 // thread as at a safepoint. This can be odd because we can be here
2093 // as _thread_in_Java which would normally transition to _thread_blocked
2094 // at a safepoint. We would like to mark the thread as _thread_blocked
2095 // before calling java_suspend_self like all other callers of it but
2096 // we must then observe proper safepoint protocol. (We can't leave
2097 // _thread_blocked with a safepoint in progress). However we can be
2098 // here as _thread_in_native_trans so we can't use a normal transition
2099 // constructor/destructor pair because they assert on that type of
2100 // transition. We could do something like:
2101 //
2102 // JavaThreadState state = thread_state();
2103 // set_thread_state(_thread_in_vm);
2104 // {
2105 // ThreadBlockInVM tbivm(this);
2106 // java_suspend_self()
2107 // }
2108 // set_thread_state(_thread_in_vm_trans);
2109 // if (safepoint) block;
2110 // set_thread_state(state);
2111 //
2112 // but that is pretty messy. Instead we just go with the way the
2113 // code has worked before and note that this is the only path to
2114 // java_suspend_self that doesn't put the thread in _thread_blocked
2115 // mode.
2116
2117 frame_anchor()->make_walkable(this);
2118 java_suspend_self();
2119
2120 // We might be here for reasons in addition to the self-suspend request
2121 // so check for other async requests.
2122 }
2123
2124 if (check_asyncs) {
2125 check_and_handle_async_exceptions();
2126 }
2127 }
2128
2129 void JavaThread::send_thread_stop(oop java_throwable) {
2130 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2131 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2132 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2133
2134 // Do not throw asynchronous exceptions against the compiler thread
2135 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2136 if (is_Compiler_thread()) return;
2137
2138 {
2139 // Actually throw the Throwable against the target Thread - however
2140 // only if there is no thread death exception installed already.
2141 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2142 // If the topmost frame is a runtime stub, then we are calling into
2143 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2144 // must deoptimize the caller before continuing, as the compiled exception handler table
2145 // may not be valid
2146 if (has_last_Java_frame()) {
2147 frame f = last_frame();
2148 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2149 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2150 RegisterMap reg_map(this, UseBiasedLocking);
2151 frame compiled_frame = f.sender(®_map);
2152 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2153 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2154 }
2155 }
2156 }
2157
2158 // Set async. pending exception in thread.
2159 set_pending_async_exception(java_throwable);
2160
2161 if (TraceExceptions) {
2162 ResourceMark rm;
2163 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2164 }
2165 // for AbortVMOnException flag
2166 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2167 }
2168 }
2169
2170
2171 // Interrupt thread so it will wake up from a potential wait()
2172 Thread::interrupt(this);
2173 }
2174
2175 // External suspension mechanism.
2176 //
2177 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2178 // to any VM_locks and it is at a transition
2179 // Self-suspension will happen on the transition out of the vm.
2180 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2181 //
2182 // Guarantees on return:
2183 // + Target thread will not execute any new bytecode (that's why we need to
2184 // force a safepoint)
2185 // + Target thread will not enter any new monitors
2186 //
2187 void JavaThread::java_suspend() {
2188 { MutexLocker mu(Threads_lock);
2189 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2190 return;
2191 }
2192 }
2193
2194 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2195 if (!is_external_suspend()) {
2196 // a racing resume has cancelled us; bail out now
2197 return;
2198 }
2199
2200 // suspend is done
2201 uint32_t debug_bits = 0;
2202 // Warning: is_ext_suspend_completed() may temporarily drop the
2203 // SR_lock to allow the thread to reach a stable thread state if
2204 // it is currently in a transient thread state.
2205 if (is_ext_suspend_completed(false /* !called_by_wait */,
2206 SuspendRetryDelay, &debug_bits)) {
2207 return;
2208 }
2209 }
2210
2211 VM_ForceSafepoint vm_suspend;
2212 VMThread::execute(&vm_suspend);
2213 }
2214
2215 // Part II of external suspension.
2216 // A JavaThread self suspends when it detects a pending external suspend
2217 // request. This is usually on transitions. It is also done in places
2218 // where continuing to the next transition would surprise the caller,
2219 // e.g., monitor entry.
2220 //
2221 // Returns the number of times that the thread self-suspended.
2222 //
2223 // Note: DO NOT call java_suspend_self() when you just want to block current
2224 // thread. java_suspend_self() is the second stage of cooperative
2225 // suspension for external suspend requests and should only be used
2226 // to complete an external suspend request.
2227 //
2228 int JavaThread::java_suspend_self() {
2229 int ret = 0;
2230
2231 // we are in the process of exiting so don't suspend
2232 if (is_exiting()) {
2233 clear_external_suspend();
2234 return ret;
2235 }
2236
2237 assert(_anchor.walkable() ||
2238 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2239 "must have walkable stack");
2240
2241 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2242
2243 assert(!this->is_ext_suspended(),
2244 "a thread trying to self-suspend should not already be suspended");
2245
2246 if (this->is_suspend_equivalent()) {
2247 // If we are self-suspending as a result of the lifting of a
2248 // suspend equivalent condition, then the suspend_equivalent
2249 // flag is not cleared until we set the ext_suspended flag so
2250 // that wait_for_ext_suspend_completion() returns consistent
2251 // results.
2252 this->clear_suspend_equivalent();
2253 }
2254
2255 // A racing resume may have cancelled us before we grabbed SR_lock
2256 // above. Or another external suspend request could be waiting for us
2257 // by the time we return from SR_lock()->wait(). The thread
2258 // that requested the suspension may already be trying to walk our
2259 // stack and if we return now, we can change the stack out from under
2260 // it. This would be a "bad thing (TM)" and cause the stack walker
2261 // to crash. We stay self-suspended until there are no more pending
2262 // external suspend requests.
2263 while (is_external_suspend()) {
2264 ret++;
2265 this->set_ext_suspended();
2266
2267 // _ext_suspended flag is cleared by java_resume()
2268 while (is_ext_suspended()) {
2269 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2270 }
2271 }
2272
2273 return ret;
2274 }
2275
2276 #ifdef ASSERT
2277 // verify the JavaThread has not yet been published in the Threads::list, and
2278 // hence doesn't need protection from concurrent access at this stage
2279 void JavaThread::verify_not_published() {
2280 if (!Threads_lock->owned_by_self()) {
2281 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2282 assert(!Threads::includes(this),
2283 "java thread shouldn't have been published yet!");
2284 } else {
2285 assert(!Threads::includes(this),
2286 "java thread shouldn't have been published yet!");
2287 }
2288 }
2289 #endif
2290
2291 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2292 // progress or when _suspend_flags is non-zero.
2293 // Current thread needs to self-suspend if there is a suspend request and/or
2294 // block if a safepoint is in progress.
2295 // Async exception ISN'T checked.
2296 // Note only the ThreadInVMfromNative transition can call this function
2297 // directly and when thread state is _thread_in_native_trans
2298 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2299 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2300
2301 JavaThread *curJT = JavaThread::current();
2302 bool do_self_suspend = thread->is_external_suspend();
2303
2304 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2305
2306 // If JNIEnv proxies are allowed, don't self-suspend if the target
2307 // thread is not the current thread. In older versions of jdbx, jdbx
2308 // threads could call into the VM with another thread's JNIEnv so we
2309 // can be here operating on behalf of a suspended thread (4432884).
2310 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2311 JavaThreadState state = thread->thread_state();
2312
2313 // We mark this thread_blocked state as a suspend-equivalent so
2314 // that a caller to is_ext_suspend_completed() won't be confused.
2315 // The suspend-equivalent state is cleared by java_suspend_self().
2316 thread->set_suspend_equivalent();
2317
2318 // If the safepoint code sees the _thread_in_native_trans state, it will
2319 // wait until the thread changes to other thread state. There is no
2320 // guarantee on how soon we can obtain the SR_lock and complete the
2321 // self-suspend request. It would be a bad idea to let safepoint wait for
2322 // too long. Temporarily change the state to _thread_blocked to
2323 // let the VM thread know that this thread is ready for GC. The problem
2324 // of changing thread state is that safepoint could happen just after
2325 // java_suspend_self() returns after being resumed, and VM thread will
2326 // see the _thread_blocked state. We must check for safepoint
2327 // after restoring the state and make sure we won't leave while a safepoint
2328 // is in progress.
2329 thread->set_thread_state(_thread_blocked);
2330 thread->java_suspend_self();
2331 thread->set_thread_state(state);
2332 // Make sure new state is seen by VM thread
2333 if (os::is_MP()) {
2334 if (UseMembar) {
2335 // Force a fence between the write above and read below
2336 OrderAccess::fence();
2337 } else {
2338 // Must use this rather than serialization page in particular on Windows
2339 InterfaceSupport::serialize_memory(thread);
2340 }
2341 }
2342 }
2343
2344 if (SafepointSynchronize::do_call_back()) {
2345 // If we are safepointing, then block the caller which may not be
2346 // the same as the target thread (see above).
2347 SafepointSynchronize::block(curJT);
2348 }
2349
2350 if (thread->is_deopt_suspend()) {
2351 thread->clear_deopt_suspend();
2352 RegisterMap map(thread, false);
2353 frame f = thread->last_frame();
2354 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2355 f = f.sender(&map);
2356 }
2357 if (f.id() == thread->must_deopt_id()) {
2358 thread->clear_must_deopt_id();
2359 f.deoptimize(thread);
2360 } else {
2361 fatal("missed deoptimization!");
2362 }
2363 }
2364 }
2365
2366 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2367 // progress or when _suspend_flags is non-zero.
2368 // Current thread needs to self-suspend if there is a suspend request and/or
2369 // block if a safepoint is in progress.
2370 // Also check for pending async exception (not including unsafe access error).
2371 // Note only the native==>VM/Java barriers can call this function and when
2372 // thread state is _thread_in_native_trans.
2373 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2374 check_safepoint_and_suspend_for_native_trans(thread);
2375
2376 if (thread->has_async_exception()) {
2377 // We are in _thread_in_native_trans state, don't handle unsafe
2378 // access error since that may block.
2379 thread->check_and_handle_async_exceptions(false);
2380 }
2381 }
2382
2383 // This is a variant of the normal
2384 // check_special_condition_for_native_trans with slightly different
2385 // semantics for use by critical native wrappers. It does all the
2386 // normal checks but also performs the transition back into
2387 // thread_in_Java state. This is required so that critical natives
2388 // can potentially block and perform a GC if they are the last thread
2389 // exiting the GC_locker.
2390 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2391 check_special_condition_for_native_trans(thread);
2392
2393 // Finish the transition
2394 thread->set_thread_state(_thread_in_Java);
2395
2396 if (thread->do_critical_native_unlock()) {
2397 ThreadInVMfromJavaNoAsyncException tiv(thread);
2398 GC_locker::unlock_critical(thread);
2399 thread->clear_critical_native_unlock();
2400 }
2401 }
2402
2403 // We need to guarantee the Threads_lock here, since resumes are not
2404 // allowed during safepoint synchronization
2405 // Can only resume from an external suspension
2406 void JavaThread::java_resume() {
2407 assert_locked_or_safepoint(Threads_lock);
2408
2409 // Sanity check: thread is gone, has started exiting or the thread
2410 // was not externally suspended.
2411 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2412 return;
2413 }
2414
2415 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2416
2417 clear_external_suspend();
2418
2419 if (is_ext_suspended()) {
2420 clear_ext_suspended();
2421 SR_lock()->notify_all();
2422 }
2423 }
2424
2425 void JavaThread::create_stack_guard_pages() {
2426 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2427 address low_addr = stack_base() - stack_size();
2428 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2429
2430 int allocate = os::allocate_stack_guard_pages();
2431 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2432
2433 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2434 warning("Attempt to allocate stack guard pages failed.");
2435 return;
2436 }
2437
2438 if (os::guard_memory((char *) low_addr, len)) {
2439 _stack_guard_state = stack_guard_enabled;
2440 } else {
2441 warning("Attempt to protect stack guard pages failed.");
2442 if (os::uncommit_memory((char *) low_addr, len)) {
2443 warning("Attempt to deallocate stack guard pages failed.");
2444 }
2445 }
2446 }
2447
2448 void JavaThread::remove_stack_guard_pages() {
2449 assert(Thread::current() == this, "from different thread");
2450 if (_stack_guard_state == stack_guard_unused) return;
2451 address low_addr = stack_base() - stack_size();
2452 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2453
2454 if (os::allocate_stack_guard_pages()) {
2455 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2456 _stack_guard_state = stack_guard_unused;
2457 } else {
2458 warning("Attempt to deallocate stack guard pages failed.");
2459 }
2460 } else {
2461 if (_stack_guard_state == stack_guard_unused) return;
2462 if (os::unguard_memory((char *) low_addr, len)) {
2463 _stack_guard_state = stack_guard_unused;
2464 } else {
2465 warning("Attempt to unprotect stack guard pages failed.");
2466 }
2467 }
2468 }
2469
2470 void JavaThread::enable_stack_yellow_zone() {
2471 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2472 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2473
2474 // The base notation is from the stacks point of view, growing downward.
2475 // We need to adjust it to work correctly with guard_memory()
2476 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2477
2478 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2479 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2480
2481 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2482 _stack_guard_state = stack_guard_enabled;
2483 } else {
2484 warning("Attempt to guard stack yellow zone failed.");
2485 }
2486 enable_register_stack_guard();
2487 }
2488
2489 void JavaThread::disable_stack_yellow_zone() {
2490 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2491 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2492
2493 // Simply return if called for a thread that does not use guard pages.
2494 if (_stack_guard_state == stack_guard_unused) return;
2495
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 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2499
2500 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2501 _stack_guard_state = stack_guard_yellow_disabled;
2502 } else {
2503 warning("Attempt to unguard stack yellow zone failed.");
2504 }
2505 disable_register_stack_guard();
2506 }
2507
2508 void JavaThread::enable_stack_red_zone() {
2509 // The base notation is from the stacks point of view, growing downward.
2510 // We need to adjust it to work correctly with guard_memory()
2511 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2512 address base = stack_red_zone_base() - stack_red_zone_size();
2513
2514 guarantee(base < stack_base(), "Error calculating stack red zone");
2515 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2516
2517 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2518 warning("Attempt to guard stack red zone failed.");
2519 }
2520 }
2521
2522 void JavaThread::disable_stack_red_zone() {
2523 // The base notation is from the stacks point of view, growing downward.
2524 // We need to adjust it to work correctly with guard_memory()
2525 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2526 address base = stack_red_zone_base() - stack_red_zone_size();
2527 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2528 warning("Attempt to unguard stack red zone failed.");
2529 }
2530 }
2531
2532 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2533 // ignore is there is no stack
2534 if (!has_last_Java_frame()) return;
2535 // traverse the stack frames. Starts from top frame.
2536 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2537 frame* fr = fst.current();
2538 f(fr, fst.register_map());
2539 }
2540 }
2541
2542
2543 #ifndef PRODUCT
2544 // Deoptimization
2545 // Function for testing deoptimization
2546 void JavaThread::deoptimize() {
2547 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2548 StackFrameStream fst(this, UseBiasedLocking);
2549 bool deopt = false; // Dump stack only if a deopt actually happens.
2550 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2551 // Iterate over all frames in the thread and deoptimize
2552 for (; !fst.is_done(); fst.next()) {
2553 if (fst.current()->can_be_deoptimized()) {
2554
2555 if (only_at) {
2556 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2557 // consists of comma or carriage return separated numbers so
2558 // search for the current bci in that string.
2559 address pc = fst.current()->pc();
2560 nmethod* nm = (nmethod*) fst.current()->cb();
2561 ScopeDesc* sd = nm->scope_desc_at(pc);
2562 char buffer[8];
2563 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2564 size_t len = strlen(buffer);
2565 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2566 while (found != NULL) {
2567 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2568 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2569 // Check that the bci found is bracketed by terminators.
2570 break;
2571 }
2572 found = strstr(found + 1, buffer);
2573 }
2574 if (!found) {
2575 continue;
2576 }
2577 }
2578
2579 if (DebugDeoptimization && !deopt) {
2580 deopt = true; // One-time only print before deopt
2581 tty->print_cr("[BEFORE Deoptimization]");
2582 trace_frames();
2583 trace_stack();
2584 }
2585 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2586 }
2587 }
2588
2589 if (DebugDeoptimization && deopt) {
2590 tty->print_cr("[AFTER Deoptimization]");
2591 trace_frames();
2592 }
2593 }
2594
2595
2596 // Make zombies
2597 void JavaThread::make_zombies() {
2598 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2599 if (fst.current()->can_be_deoptimized()) {
2600 // it is a Java nmethod
2601 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2602 nm->make_not_entrant();
2603 }
2604 }
2605 }
2606 #endif // PRODUCT
2607
2608
2609 void JavaThread::deoptimized_wrt_marked_nmethods() {
2610 if (!has_last_Java_frame()) return;
2611 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2612 StackFrameStream fst(this, UseBiasedLocking);
2613 for (; !fst.is_done(); fst.next()) {
2614 if (fst.current()->should_be_deoptimized()) {
2615 if (LogCompilation && xtty != NULL) {
2616 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2617 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2618 this->name(), nm != NULL ? nm->compile_id() : -1);
2619 }
2620
2621 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2622 }
2623 }
2624 }
2625
2626
2627 // If the caller is a NamedThread, then remember, in the current scope,
2628 // the given JavaThread in its _processed_thread field.
2629 class RememberProcessedThread: public StackObj {
2630 NamedThread* _cur_thr;
2631 public:
2632 RememberProcessedThread(JavaThread* jthr) {
2633 Thread* thread = Thread::current();
2634 if (thread->is_Named_thread()) {
2635 _cur_thr = (NamedThread *)thread;
2636 _cur_thr->set_processed_thread(jthr);
2637 } else {
2638 _cur_thr = NULL;
2639 }
2640 }
2641
2642 ~RememberProcessedThread() {
2643 if (_cur_thr) {
2644 _cur_thr->set_processed_thread(NULL);
2645 }
2646 }
2647 };
2648
2649 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2650 // Verify that the deferred card marks have been flushed.
2651 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2652
2653 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2654 // since there may be more than one thread using each ThreadProfiler.
2655
2656 // Traverse the GCHandles
2657 Thread::oops_do(f, cld_f, cf);
2658
2659 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2660 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2661
2662 if (has_last_Java_frame()) {
2663 // Record JavaThread to GC thread
2664 RememberProcessedThread rpt(this);
2665
2666 // Traverse the privileged stack
2667 if (_privileged_stack_top != NULL) {
2668 _privileged_stack_top->oops_do(f);
2669 }
2670
2671 // traverse the registered growable array
2672 if (_array_for_gc != NULL) {
2673 for (int index = 0; index < _array_for_gc->length(); index++) {
2674 f->do_oop(_array_for_gc->adr_at(index));
2675 }
2676 }
2677
2678 // Traverse the monitor chunks
2679 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2680 chunk->oops_do(f);
2681 }
2682
2683 // Traverse the execution stack
2684 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2685 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2686 }
2687 }
2688
2689 // callee_target is never live across a gc point so NULL it here should
2690 // it still contain a methdOop.
2691
2692 set_callee_target(NULL);
2693
2694 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2695 // If we have deferred set_locals there might be oops waiting to be
2696 // written
2697 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2698 if (list != NULL) {
2699 for (int i = 0; i < list->length(); i++) {
2700 list->at(i)->oops_do(f);
2701 }
2702 }
2703
2704 // Traverse instance variables at the end since the GC may be moving things
2705 // around using this function
2706 f->do_oop((oop*) &_threadObj);
2707 f->do_oop((oop*) &_vm_result);
2708 f->do_oop((oop*) &_exception_oop);
2709 f->do_oop((oop*) &_pending_async_exception);
2710
2711 if (jvmti_thread_state() != NULL) {
2712 jvmti_thread_state()->oops_do(f);
2713 }
2714 }
2715
2716 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2717 Thread::nmethods_do(cf); // (super method is a no-op)
2718
2719 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2720 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2721
2722 if (has_last_Java_frame()) {
2723 // Traverse the execution stack
2724 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2725 fst.current()->nmethods_do(cf);
2726 }
2727 }
2728 }
2729
2730 void JavaThread::metadata_do(void f(Metadata*)) {
2731 if (has_last_Java_frame()) {
2732 // Traverse the execution stack to call f() on the methods in the stack
2733 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2734 fst.current()->metadata_do(f);
2735 }
2736 } else if (is_Compiler_thread()) {
2737 // need to walk ciMetadata in current compile tasks to keep alive.
2738 CompilerThread* ct = (CompilerThread*)this;
2739 if (ct->env() != NULL) {
2740 ct->env()->metadata_do(f);
2741 }
2742 }
2743 }
2744
2745 // Printing
2746 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2747 switch (_thread_state) {
2748 case _thread_uninitialized: return "_thread_uninitialized";
2749 case _thread_new: return "_thread_new";
2750 case _thread_new_trans: return "_thread_new_trans";
2751 case _thread_in_native: return "_thread_in_native";
2752 case _thread_in_native_trans: return "_thread_in_native_trans";
2753 case _thread_in_vm: return "_thread_in_vm";
2754 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2755 case _thread_in_Java: return "_thread_in_Java";
2756 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2757 case _thread_blocked: return "_thread_blocked";
2758 case _thread_blocked_trans: return "_thread_blocked_trans";
2759 default: return "unknown thread state";
2760 }
2761 }
2762
2763 #ifndef PRODUCT
2764 void JavaThread::print_thread_state_on(outputStream *st) const {
2765 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2766 };
2767 void JavaThread::print_thread_state() const {
2768 print_thread_state_on(tty);
2769 }
2770 #endif // PRODUCT
2771
2772 // Called by Threads::print() for VM_PrintThreads operation
2773 void JavaThread::print_on(outputStream *st) const {
2774 st->print("\"%s\" ", get_thread_name());
2775 oop thread_oop = threadObj();
2776 if (thread_oop != NULL) {
2777 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2778 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2779 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2780 }
2781 Thread::print_on(st);
2782 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2783 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2784 if (thread_oop != NULL) {
2785 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2786 }
2787 #ifndef PRODUCT
2788 print_thread_state_on(st);
2789 _safepoint_state->print_on(st);
2790 #endif // PRODUCT
2791 }
2792
2793 // Called by fatal error handler. The difference between this and
2794 // JavaThread::print() is that we can't grab lock or allocate memory.
2795 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2796 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2797 oop thread_obj = threadObj();
2798 if (thread_obj != NULL) {
2799 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2800 }
2801 st->print(" [");
2802 st->print("%s", _get_thread_state_name(_thread_state));
2803 if (osthread()) {
2804 st->print(", id=%d", osthread()->thread_id());
2805 }
2806 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2807 _stack_base - _stack_size, _stack_base);
2808 st->print("]");
2809 return;
2810 }
2811
2812 // Verification
2813
2814 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2815
2816 void JavaThread::verify() {
2817 // Verify oops in the thread.
2818 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2819
2820 // Verify the stack frames.
2821 frames_do(frame_verify);
2822 }
2823
2824 // CR 6300358 (sub-CR 2137150)
2825 // Most callers of this method assume that it can't return NULL but a
2826 // thread may not have a name whilst it is in the process of attaching to
2827 // the VM - see CR 6412693, and there are places where a JavaThread can be
2828 // seen prior to having it's threadObj set (eg JNI attaching threads and
2829 // if vm exit occurs during initialization). These cases can all be accounted
2830 // for such that this method never returns NULL.
2831 const char* JavaThread::get_thread_name() const {
2832 #ifdef ASSERT
2833 // early safepoints can hit while current thread does not yet have TLS
2834 if (!SafepointSynchronize::is_at_safepoint()) {
2835 Thread *cur = Thread::current();
2836 if (!(cur->is_Java_thread() && cur == this)) {
2837 // Current JavaThreads are allowed to get their own name without
2838 // the Threads_lock.
2839 assert_locked_or_safepoint(Threads_lock);
2840 }
2841 }
2842 #endif // ASSERT
2843 return get_thread_name_string();
2844 }
2845
2846 // Returns a non-NULL representation of this thread's name, or a suitable
2847 // descriptive string if there is no set name
2848 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2849 const char* name_str;
2850 oop thread_obj = threadObj();
2851 if (thread_obj != NULL) {
2852 oop name = java_lang_Thread::name(thread_obj);
2853 if (name != NULL) {
2854 if (buf == NULL) {
2855 name_str = java_lang_String::as_utf8_string(name);
2856 } else {
2857 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2858 }
2859 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2860 name_str = "<no-name - thread is attaching>";
2861 } else {
2862 name_str = Thread::name();
2863 }
2864 } else {
2865 name_str = Thread::name();
2866 }
2867 assert(name_str != NULL, "unexpected NULL thread name");
2868 return name_str;
2869 }
2870
2871
2872 const char* JavaThread::get_threadgroup_name() const {
2873 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2874 oop thread_obj = threadObj();
2875 if (thread_obj != NULL) {
2876 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2877 if (thread_group != NULL) {
2878 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2879 // ThreadGroup.name can be null
2880 if (name != NULL) {
2881 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2882 return str;
2883 }
2884 }
2885 }
2886 return NULL;
2887 }
2888
2889 const char* JavaThread::get_parent_name() const {
2890 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2891 oop thread_obj = threadObj();
2892 if (thread_obj != NULL) {
2893 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2894 if (thread_group != NULL) {
2895 oop parent = java_lang_ThreadGroup::parent(thread_group);
2896 if (parent != NULL) {
2897 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2898 // ThreadGroup.name can be null
2899 if (name != NULL) {
2900 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2901 return str;
2902 }
2903 }
2904 }
2905 }
2906 return NULL;
2907 }
2908
2909 ThreadPriority JavaThread::java_priority() const {
2910 oop thr_oop = threadObj();
2911 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2912 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2913 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2914 return priority;
2915 }
2916
2917 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2918
2919 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2920 // Link Java Thread object <-> C++ Thread
2921
2922 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2923 // and put it into a new Handle. The Handle "thread_oop" can then
2924 // be used to pass the C++ thread object to other methods.
2925
2926 // Set the Java level thread object (jthread) field of the
2927 // new thread (a JavaThread *) to C++ thread object using the
2928 // "thread_oop" handle.
2929
2930 // Set the thread field (a JavaThread *) of the
2931 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2932
2933 Handle thread_oop(Thread::current(),
2934 JNIHandles::resolve_non_null(jni_thread));
2935 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2936 "must be initialized");
2937 set_threadObj(thread_oop());
2938 java_lang_Thread::set_thread(thread_oop(), this);
2939
2940 if (prio == NoPriority) {
2941 prio = java_lang_Thread::priority(thread_oop());
2942 assert(prio != NoPriority, "A valid priority should be present");
2943 }
2944
2945 // Push the Java priority down to the native thread; needs Threads_lock
2946 Thread::set_priority(this, prio);
2947
2948 prepare_ext();
2949
2950 // Add the new thread to the Threads list and set it in motion.
2951 // We must have threads lock in order to call Threads::add.
2952 // It is crucial that we do not block before the thread is
2953 // added to the Threads list for if a GC happens, then the java_thread oop
2954 // will not be visited by GC.
2955 Threads::add(this);
2956 }
2957
2958 oop JavaThread::current_park_blocker() {
2959 // Support for JSR-166 locks
2960 oop thread_oop = threadObj();
2961 if (thread_oop != NULL &&
2962 JDK_Version::current().supports_thread_park_blocker()) {
2963 return java_lang_Thread::park_blocker(thread_oop);
2964 }
2965 return NULL;
2966 }
2967
2968
2969 void JavaThread::print_stack_on(outputStream* st) {
2970 if (!has_last_Java_frame()) return;
2971 ResourceMark rm;
2972 HandleMark hm;
2973
2974 RegisterMap reg_map(this);
2975 vframe* start_vf = last_java_vframe(®_map);
2976 int count = 0;
2977 for (vframe* f = start_vf; f; f = f->sender()) {
2978 if (f->is_java_frame()) {
2979 javaVFrame* jvf = javaVFrame::cast(f);
2980 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2981
2982 // Print out lock information
2983 if (JavaMonitorsInStackTrace) {
2984 jvf->print_lock_info_on(st, count);
2985 }
2986 } else {
2987 // Ignore non-Java frames
2988 }
2989
2990 // Bail-out case for too deep stacks
2991 count++;
2992 if (MaxJavaStackTraceDepth == count) return;
2993 }
2994 }
2995
2996
2997 // JVMTI PopFrame support
2998 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2999 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3000 if (in_bytes(size_in_bytes) != 0) {
3001 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3002 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3003 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3004 }
3005 }
3006
3007 void* JavaThread::popframe_preserved_args() {
3008 return _popframe_preserved_args;
3009 }
3010
3011 ByteSize JavaThread::popframe_preserved_args_size() {
3012 return in_ByteSize(_popframe_preserved_args_size);
3013 }
3014
3015 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3016 int sz = in_bytes(popframe_preserved_args_size());
3017 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3018 return in_WordSize(sz / wordSize);
3019 }
3020
3021 void JavaThread::popframe_free_preserved_args() {
3022 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3023 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3024 _popframe_preserved_args = NULL;
3025 _popframe_preserved_args_size = 0;
3026 }
3027
3028 #ifndef PRODUCT
3029
3030 void JavaThread::trace_frames() {
3031 tty->print_cr("[Describe stack]");
3032 int frame_no = 1;
3033 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3034 tty->print(" %d. ", frame_no++);
3035 fst.current()->print_value_on(tty, this);
3036 tty->cr();
3037 }
3038 }
3039
3040 class PrintAndVerifyOopClosure: public OopClosure {
3041 protected:
3042 template <class T> inline void do_oop_work(T* p) {
3043 oop obj = oopDesc::load_decode_heap_oop(p);
3044 if (obj == NULL) return;
3045 tty->print(INTPTR_FORMAT ": ", p);
3046 if (obj->is_oop_or_null()) {
3047 if (obj->is_objArray()) {
3048 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3049 } else {
3050 obj->print();
3051 }
3052 } else {
3053 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3054 }
3055 tty->cr();
3056 }
3057 public:
3058 virtual void do_oop(oop* p) { do_oop_work(p); }
3059 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3060 };
3061
3062
3063 static void oops_print(frame* f, const RegisterMap *map) {
3064 PrintAndVerifyOopClosure print;
3065 f->print_value();
3066 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3067 }
3068
3069 // Print our all the locations that contain oops and whether they are
3070 // valid or not. This useful when trying to find the oldest frame
3071 // where an oop has gone bad since the frame walk is from youngest to
3072 // oldest.
3073 void JavaThread::trace_oops() {
3074 tty->print_cr("[Trace oops]");
3075 frames_do(oops_print);
3076 }
3077
3078
3079 #ifdef ASSERT
3080 // Print or validate the layout of stack frames
3081 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3082 ResourceMark rm;
3083 PRESERVE_EXCEPTION_MARK;
3084 FrameValues values;
3085 int frame_no = 0;
3086 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3087 fst.current()->describe(values, ++frame_no);
3088 if (depth == frame_no) break;
3089 }
3090 if (validate_only) {
3091 values.validate();
3092 } else {
3093 tty->print_cr("[Describe stack layout]");
3094 values.print(this);
3095 }
3096 }
3097 #endif
3098
3099 void JavaThread::trace_stack_from(vframe* start_vf) {
3100 ResourceMark rm;
3101 int vframe_no = 1;
3102 for (vframe* f = start_vf; f; f = f->sender()) {
3103 if (f->is_java_frame()) {
3104 javaVFrame::cast(f)->print_activation(vframe_no++);
3105 } else {
3106 f->print();
3107 }
3108 if (vframe_no > StackPrintLimit) {
3109 tty->print_cr("...<more frames>...");
3110 return;
3111 }
3112 }
3113 }
3114
3115
3116 void JavaThread::trace_stack() {
3117 if (!has_last_Java_frame()) return;
3118 ResourceMark rm;
3119 HandleMark hm;
3120 RegisterMap reg_map(this);
3121 trace_stack_from(last_java_vframe(®_map));
3122 }
3123
3124
3125 #endif // PRODUCT
3126
3127
3128 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3129 assert(reg_map != NULL, "a map must be given");
3130 frame f = last_frame();
3131 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3132 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3133 }
3134 return NULL;
3135 }
3136
3137
3138 Klass* JavaThread::security_get_caller_class(int depth) {
3139 vframeStream vfst(this);
3140 vfst.security_get_caller_frame(depth);
3141 if (!vfst.at_end()) {
3142 return vfst.method()->method_holder();
3143 }
3144 return NULL;
3145 }
3146
3147 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3148 assert(thread->is_Compiler_thread(), "must be compiler thread");
3149 CompileBroker::compiler_thread_loop();
3150 }
3151
3152 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3153 NMethodSweeper::sweeper_loop();
3154 }
3155
3156 // Create a CompilerThread
3157 CompilerThread::CompilerThread(CompileQueue* queue,
3158 CompilerCounters* counters)
3159 : JavaThread(&compiler_thread_entry) {
3160 _env = NULL;
3161 _log = NULL;
3162 _task = NULL;
3163 _queue = queue;
3164 _counters = counters;
3165 _buffer_blob = NULL;
3166 _compiler = NULL;
3167
3168 #ifndef PRODUCT
3169 _ideal_graph_printer = NULL;
3170 #endif
3171 }
3172
3173 // Create sweeper thread
3174 CodeCacheSweeperThread::CodeCacheSweeperThread()
3175 : JavaThread(&sweeper_thread_entry) {
3176 _scanned_nmethod = NULL;
3177 }
3178 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3179 JavaThread::oops_do(f, cld_f, cf);
3180 if (_scanned_nmethod != NULL && cf != NULL) {
3181 // Safepoints can occur when the sweeper is scanning an nmethod so
3182 // process it here to make sure it isn't unloaded in the middle of
3183 // a scan.
3184 cf->do_code_blob(_scanned_nmethod);
3185 }
3186 }
3187
3188
3189 // ======= Threads ========
3190
3191 // The Threads class links together all active threads, and provides
3192 // operations over all threads. It is protected by its own Mutex
3193 // lock, which is also used in other contexts to protect thread
3194 // operations from having the thread being operated on from exiting
3195 // and going away unexpectedly (e.g., safepoint synchronization)
3196
3197 JavaThread* Threads::_thread_list = NULL;
3198 int Threads::_number_of_threads = 0;
3199 int Threads::_number_of_non_daemon_threads = 0;
3200 int Threads::_return_code = 0;
3201 int Threads::_thread_claim_parity = 0;
3202 size_t JavaThread::_stack_size_at_create = 0;
3203 #ifdef ASSERT
3204 bool Threads::_vm_complete = false;
3205 #endif
3206
3207 // All JavaThreads
3208 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3209
3210 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3211 void Threads::threads_do(ThreadClosure* tc) {
3212 assert_locked_or_safepoint(Threads_lock);
3213 // ALL_JAVA_THREADS iterates through all JavaThreads
3214 ALL_JAVA_THREADS(p) {
3215 tc->do_thread(p);
3216 }
3217 // Someday we could have a table or list of all non-JavaThreads.
3218 // For now, just manually iterate through them.
3219 tc->do_thread(VMThread::vm_thread());
3220 Universe::heap()->gc_threads_do(tc);
3221 WatcherThread *wt = WatcherThread::watcher_thread();
3222 // Strictly speaking, the following NULL check isn't sufficient to make sure
3223 // the data for WatcherThread is still valid upon being examined. However,
3224 // considering that WatchThread terminates when the VM is on the way to
3225 // exit at safepoint, the chance of the above is extremely small. The right
3226 // way to prevent termination of WatcherThread would be to acquire
3227 // Terminator_lock, but we can't do that without violating the lock rank
3228 // checking in some cases.
3229 if (wt != NULL) {
3230 tc->do_thread(wt);
3231 }
3232
3233 // If CompilerThreads ever become non-JavaThreads, add them here
3234 }
3235
3236 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3237 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3238
3239 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3240 create_vm_init_libraries();
3241 }
3242
3243 initialize_class(vmSymbols::java_lang_String(), CHECK);
3244
3245 // Initialize java_lang.System (needed before creating the thread)
3246 initialize_class(vmSymbols::java_lang_System(), CHECK);
3247 // The VM creates & returns objects of this class. Make sure it's initialized.
3248 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3249 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3250 Handle thread_group = create_initial_thread_group(CHECK);
3251 Universe::set_main_thread_group(thread_group());
3252 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3253 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3254 main_thread->set_threadObj(thread_object);
3255 // Set thread status to running since main thread has
3256 // been started and running.
3257 java_lang_Thread::set_thread_status(thread_object,
3258 java_lang_Thread::RUNNABLE);
3259
3260 // The VM preresolves methods to these classes. Make sure that they get initialized
3261 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3262 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3263 call_initializeSystemClass(CHECK);
3264
3265 // get the Java runtime name after java.lang.System is initialized
3266 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3267 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3268
3269 // an instance of OutOfMemory exception has been allocated earlier
3270 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3271 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3272 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3273 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3274 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3275 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3276 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3277 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3278 }
3279
3280 void Threads::initialize_jsr292_core_classes(TRAPS) {
3281 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3282 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3283 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3284 }
3285
3286 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3287 extern void JDK_Version_init();
3288
3289 // Preinitialize version info.
3290 VM_Version::early_initialize();
3291
3292 // Check version
3293 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3294
3295 // Initialize the output stream module
3296 ostream_init();
3297
3298 // Process java launcher properties.
3299 Arguments::process_sun_java_launcher_properties(args);
3300
3301 // Initialize the os module before using TLS
3302 os::init();
3303
3304 // Initialize system properties.
3305 Arguments::init_system_properties();
3306
3307 // So that JDK version can be used as a discriminator when parsing arguments
3308 JDK_Version_init();
3309
3310 // Update/Initialize System properties after JDK version number is known
3311 Arguments::init_version_specific_system_properties();
3312
3313 // Parse arguments
3314 jint parse_result = Arguments::parse(args);
3315 if (parse_result != JNI_OK) return parse_result;
3316
3317 os::init_before_ergo();
3318
3319 jint ergo_result = Arguments::apply_ergo();
3320 if (ergo_result != JNI_OK) return ergo_result;
3321
3322 // Final check of all arguments after ergonomics which may change values.
3323 if (!CommandLineFlags::check_all_ranges_and_constraints()) {
3324 return JNI_EINVAL;
3325 }
3326
3327 if (PauseAtStartup) {
3328 os::pause();
3329 }
3330
3331 HOTSPOT_VM_INIT_BEGIN();
3332
3333 // Record VM creation timing statistics
3334 TraceVmCreationTime create_vm_timer;
3335 create_vm_timer.start();
3336
3337 // Timing (must come after argument parsing)
3338 TraceTime timer("Create VM", TraceStartupTime);
3339
3340 // Initialize the os module after parsing the args
3341 jint os_init_2_result = os::init_2();
3342 if (os_init_2_result != JNI_OK) return os_init_2_result;
3343
3344 jint adjust_after_os_result = Arguments::adjust_after_os();
3345 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3346
3347 // initialize TLS
3348 ThreadLocalStorage::init();
3349
3350 // Initialize output stream logging
3351 ostream_init_log();
3352
3353 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3354 // Must be before create_vm_init_agents()
3355 if (Arguments::init_libraries_at_startup()) {
3356 convert_vm_init_libraries_to_agents();
3357 }
3358
3359 // Launch -agentlib/-agentpath and converted -Xrun agents
3360 if (Arguments::init_agents_at_startup()) {
3361 create_vm_init_agents();
3362 }
3363
3364 // Initialize Threads state
3365 _thread_list = NULL;
3366 _number_of_threads = 0;
3367 _number_of_non_daemon_threads = 0;
3368
3369 // Initialize global data structures and create system classes in heap
3370 vm_init_globals();
3371
3372 // Attach the main thread to this os thread
3373 JavaThread* main_thread = new JavaThread();
3374 main_thread->set_thread_state(_thread_in_vm);
3375 // must do this before set_active_handles and initialize_thread_local_storage
3376 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3377 // change the stack size recorded here to one based on the java thread
3378 // stacksize. This adjusted size is what is used to figure the placement
3379 // of the guard pages.
3380 main_thread->record_stack_base_and_size();
3381 main_thread->initialize_thread_local_storage();
3382
3383 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3384
3385 if (!main_thread->set_as_starting_thread()) {
3386 vm_shutdown_during_initialization(
3387 "Failed necessary internal allocation. Out of swap space");
3388 delete main_thread;
3389 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3390 return JNI_ENOMEM;
3391 }
3392
3393 // Enable guard page *after* os::create_main_thread(), otherwise it would
3394 // crash Linux VM, see notes in os_linux.cpp.
3395 main_thread->create_stack_guard_pages();
3396
3397 // Initialize Java-Level synchronization subsystem
3398 ObjectMonitor::Initialize();
3399
3400 // Initialize global modules
3401 jint status = init_globals();
3402 if (status != JNI_OK) {
3403 delete main_thread;
3404 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3405 return status;
3406 }
3407
3408 // Should be done after the heap is fully created
3409 main_thread->cache_global_variables();
3410
3411 HandleMark hm;
3412
3413 { MutexLocker mu(Threads_lock);
3414 Threads::add(main_thread);
3415 }
3416
3417 // Any JVMTI raw monitors entered in onload will transition into
3418 // real raw monitor. VM is setup enough here for raw monitor enter.
3419 JvmtiExport::transition_pending_onload_raw_monitors();
3420
3421 // Create the VMThread
3422 { TraceTime timer("Start VMThread", TraceStartupTime);
3423 VMThread::create();
3424 Thread* vmthread = VMThread::vm_thread();
3425
3426 if (!os::create_thread(vmthread, os::vm_thread)) {
3427 vm_exit_during_initialization("Cannot create VM thread. "
3428 "Out of system resources.");
3429 }
3430
3431 // Wait for the VM thread to become ready, and VMThread::run to initialize
3432 // Monitors can have spurious returns, must always check another state flag
3433 {
3434 MutexLocker ml(Notify_lock);
3435 os::start_thread(vmthread);
3436 while (vmthread->active_handles() == NULL) {
3437 Notify_lock->wait();
3438 }
3439 }
3440 }
3441
3442 assert(Universe::is_fully_initialized(), "not initialized");
3443 if (VerifyDuringStartup) {
3444 // Make sure we're starting with a clean slate.
3445 VM_Verify verify_op;
3446 VMThread::execute(&verify_op);
3447 }
3448
3449 Thread* THREAD = Thread::current();
3450
3451 // At this point, the Universe is initialized, but we have not executed
3452 // any byte code. Now is a good time (the only time) to dump out the
3453 // internal state of the JVM for sharing.
3454 if (DumpSharedSpaces) {
3455 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3456 ShouldNotReachHere();
3457 }
3458
3459 // Always call even when there are not JVMTI environments yet, since environments
3460 // may be attached late and JVMTI must track phases of VM execution
3461 JvmtiExport::enter_start_phase();
3462
3463 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3464 JvmtiExport::post_vm_start();
3465
3466 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3467
3468 // We need this for ClassDataSharing - the initial vm.info property is set
3469 // with the default value of CDS "sharing" which may be reset through
3470 // command line options.
3471 reset_vm_info_property(CHECK_JNI_ERR);
3472
3473 quicken_jni_functions();
3474
3475 // Must be run after init_ft which initializes ft_enabled
3476 if (TRACE_INITIALIZE() != JNI_OK) {
3477 vm_exit_during_initialization("Failed to initialize tracing backend");
3478 }
3479
3480 // Set flag that basic initialization has completed. Used by exceptions and various
3481 // debug stuff, that does not work until all basic classes have been initialized.
3482 set_init_completed();
3483
3484 Metaspace::post_initialize();
3485
3486 HOTSPOT_VM_INIT_END();
3487
3488 // record VM initialization completion time
3489 #if INCLUDE_MANAGEMENT
3490 Management::record_vm_init_completed();
3491 #endif // INCLUDE_MANAGEMENT
3492
3493 // Compute system loader. Note that this has to occur after set_init_completed, since
3494 // valid exceptions may be thrown in the process.
3495 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3496 // set_init_completed has just been called, causing exceptions not to be shortcut
3497 // anymore. We call vm_exit_during_initialization directly instead.
3498 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3499
3500 #if INCLUDE_ALL_GCS
3501 // Support for ConcurrentMarkSweep. This should be cleaned up
3502 // and better encapsulated. The ugly nested if test would go away
3503 // once things are properly refactored. XXX YSR
3504 if (UseConcMarkSweepGC || UseG1GC) {
3505 if (UseConcMarkSweepGC) {
3506 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3507 } else {
3508 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3509 }
3510 }
3511 #endif // INCLUDE_ALL_GCS
3512
3513 // Always call even when there are not JVMTI environments yet, since environments
3514 // may be attached late and JVMTI must track phases of VM execution
3515 JvmtiExport::enter_live_phase();
3516
3517 // Signal Dispatcher needs to be started before VMInit event is posted
3518 os::signal_init();
3519
3520 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3521 if (!DisableAttachMechanism) {
3522 AttachListener::vm_start();
3523 if (StartAttachListener || AttachListener::init_at_startup()) {
3524 AttachListener::init();
3525 }
3526 }
3527
3528 // Launch -Xrun agents
3529 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3530 // back-end can launch with -Xdebug -Xrunjdwp.
3531 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3532 create_vm_init_libraries();
3533 }
3534
3535 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3536 JvmtiExport::post_vm_initialized();
3537
3538 if (TRACE_START() != JNI_OK) {
3539 vm_exit_during_initialization("Failed to start tracing backend.");
3540 }
3541
3542 if (CleanChunkPoolAsync) {
3543 Chunk::start_chunk_pool_cleaner_task();
3544 }
3545
3546 // initialize compiler(s)
3547 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3548 CompileBroker::compilation_init();
3549 #endif
3550
3551 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3552 // It is done after compilers are initialized, because otherwise compilations of
3553 // signature polymorphic MH intrinsics can be missed
3554 // (see SystemDictionary::find_method_handle_intrinsic).
3555 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3556
3557 #if INCLUDE_MANAGEMENT
3558 Management::initialize(THREAD);
3559
3560 if (HAS_PENDING_EXCEPTION) {
3561 // management agent fails to start possibly due to
3562 // configuration problem and is responsible for printing
3563 // stack trace if appropriate. Simply exit VM.
3564 vm_exit(1);
3565 }
3566 #endif // INCLUDE_MANAGEMENT
3567
3568 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3569 if (MemProfiling) MemProfiler::engage();
3570 StatSampler::engage();
3571 if (CheckJNICalls) JniPeriodicChecker::engage();
3572
3573 BiasedLocking::init();
3574
3575 #if INCLUDE_RTM_OPT
3576 RTMLockingCounters::init();
3577 #endif
3578
3579 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3580 call_postVMInitHook(THREAD);
3581 // The Java side of PostVMInitHook.run must deal with all
3582 // exceptions and provide means of diagnosis.
3583 if (HAS_PENDING_EXCEPTION) {
3584 CLEAR_PENDING_EXCEPTION;
3585 }
3586 }
3587
3588 {
3589 MutexLocker ml(PeriodicTask_lock);
3590 // Make sure the WatcherThread can be started by WatcherThread::start()
3591 // or by dynamic enrollment.
3592 WatcherThread::make_startable();
3593 // Start up the WatcherThread if there are any periodic tasks
3594 // NOTE: All PeriodicTasks should be registered by now. If they
3595 // aren't, late joiners might appear to start slowly (we might
3596 // take a while to process their first tick).
3597 if (PeriodicTask::num_tasks() > 0) {
3598 WatcherThread::start();
3599 }
3600 }
3601
3602 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3603
3604 create_vm_timer.end();
3605 #ifdef ASSERT
3606 _vm_complete = true;
3607 #endif
3608 return JNI_OK;
3609 }
3610
3611 // type for the Agent_OnLoad and JVM_OnLoad entry points
3612 extern "C" {
3613 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3614 }
3615 // Find a command line agent library and return its entry point for
3616 // -agentlib: -agentpath: -Xrun
3617 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3618 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3619 const char *on_load_symbols[],
3620 size_t num_symbol_entries) {
3621 OnLoadEntry_t on_load_entry = NULL;
3622 void *library = NULL;
3623
3624 if (!agent->valid()) {
3625 char buffer[JVM_MAXPATHLEN];
3626 char ebuf[1024] = "";
3627 const char *name = agent->name();
3628 const char *msg = "Could not find agent library ";
3629
3630 // First check to see if agent is statically linked into executable
3631 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3632 library = agent->os_lib();
3633 } else if (agent->is_absolute_path()) {
3634 library = os::dll_load(name, ebuf, sizeof ebuf);
3635 if (library == NULL) {
3636 const char *sub_msg = " in absolute path, with error: ";
3637 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3638 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3639 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3640 // If we can't find the agent, exit.
3641 vm_exit_during_initialization(buf, NULL);
3642 FREE_C_HEAP_ARRAY(char, buf);
3643 }
3644 } else {
3645 // Try to load the agent from the standard dll directory
3646 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3647 name)) {
3648 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3649 }
3650 if (library == NULL) { // Try the local directory
3651 char ns[1] = {0};
3652 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3653 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3654 }
3655 if (library == NULL) {
3656 const char *sub_msg = " on the library path, with error: ";
3657 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3658 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3659 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3660 // If we can't find the agent, exit.
3661 vm_exit_during_initialization(buf, NULL);
3662 FREE_C_HEAP_ARRAY(char, buf);
3663 }
3664 }
3665 }
3666 agent->set_os_lib(library);
3667 agent->set_valid();
3668 }
3669
3670 // Find the OnLoad function.
3671 on_load_entry =
3672 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3673 false,
3674 on_load_symbols,
3675 num_symbol_entries));
3676 return on_load_entry;
3677 }
3678
3679 // Find the JVM_OnLoad entry point
3680 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3681 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3682 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3683 }
3684
3685 // Find the Agent_OnLoad entry point
3686 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3687 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3688 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3689 }
3690
3691 // For backwards compatibility with -Xrun
3692 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3693 // treated like -agentpath:
3694 // Must be called before agent libraries are created
3695 void Threads::convert_vm_init_libraries_to_agents() {
3696 AgentLibrary* agent;
3697 AgentLibrary* next;
3698
3699 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3700 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3701 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3702
3703 // If there is an JVM_OnLoad function it will get called later,
3704 // otherwise see if there is an Agent_OnLoad
3705 if (on_load_entry == NULL) {
3706 on_load_entry = lookup_agent_on_load(agent);
3707 if (on_load_entry != NULL) {
3708 // switch it to the agent list -- so that Agent_OnLoad will be called,
3709 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3710 Arguments::convert_library_to_agent(agent);
3711 } else {
3712 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3713 }
3714 }
3715 }
3716 }
3717
3718 // Create agents for -agentlib: -agentpath: and converted -Xrun
3719 // Invokes Agent_OnLoad
3720 // Called very early -- before JavaThreads exist
3721 void Threads::create_vm_init_agents() {
3722 extern struct JavaVM_ main_vm;
3723 AgentLibrary* agent;
3724
3725 JvmtiExport::enter_onload_phase();
3726
3727 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3728 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3729
3730 if (on_load_entry != NULL) {
3731 // Invoke the Agent_OnLoad function
3732 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3733 if (err != JNI_OK) {
3734 vm_exit_during_initialization("agent library failed to init", agent->name());
3735 }
3736 } else {
3737 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3738 }
3739 }
3740 JvmtiExport::enter_primordial_phase();
3741 }
3742
3743 extern "C" {
3744 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3745 }
3746
3747 void Threads::shutdown_vm_agents() {
3748 // Send any Agent_OnUnload notifications
3749 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3750 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3751 extern struct JavaVM_ main_vm;
3752 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3753
3754 // Find the Agent_OnUnload function.
3755 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3756 os::find_agent_function(agent,
3757 false,
3758 on_unload_symbols,
3759 num_symbol_entries));
3760
3761 // Invoke the Agent_OnUnload function
3762 if (unload_entry != NULL) {
3763 JavaThread* thread = JavaThread::current();
3764 ThreadToNativeFromVM ttn(thread);
3765 HandleMark hm(thread);
3766 (*unload_entry)(&main_vm);
3767 }
3768 }
3769 }
3770
3771 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3772 // Invokes JVM_OnLoad
3773 void Threads::create_vm_init_libraries() {
3774 extern struct JavaVM_ main_vm;
3775 AgentLibrary* agent;
3776
3777 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3778 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3779
3780 if (on_load_entry != NULL) {
3781 // Invoke the JVM_OnLoad function
3782 JavaThread* thread = JavaThread::current();
3783 ThreadToNativeFromVM ttn(thread);
3784 HandleMark hm(thread);
3785 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3786 if (err != JNI_OK) {
3787 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3788 }
3789 } else {
3790 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3791 }
3792 }
3793 }
3794
3795 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3796 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3797
3798 JavaThread* java_thread = NULL;
3799 // Sequential search for now. Need to do better optimization later.
3800 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3801 oop tobj = thread->threadObj();
3802 if (!thread->is_exiting() &&
3803 tobj != NULL &&
3804 java_tid == java_lang_Thread::thread_id(tobj)) {
3805 java_thread = thread;
3806 break;
3807 }
3808 }
3809 return java_thread;
3810 }
3811
3812
3813 // Last thread running calls java.lang.Shutdown.shutdown()
3814 void JavaThread::invoke_shutdown_hooks() {
3815 HandleMark hm(this);
3816
3817 // We could get here with a pending exception, if so clear it now.
3818 if (this->has_pending_exception()) {
3819 this->clear_pending_exception();
3820 }
3821
3822 EXCEPTION_MARK;
3823 Klass* k =
3824 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3825 THREAD);
3826 if (k != NULL) {
3827 // SystemDictionary::resolve_or_null will return null if there was
3828 // an exception. If we cannot load the Shutdown class, just don't
3829 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3830 // and finalizers (if runFinalizersOnExit is set) won't be run.
3831 // Note that if a shutdown hook was registered or runFinalizersOnExit
3832 // was called, the Shutdown class would have already been loaded
3833 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3834 instanceKlassHandle shutdown_klass (THREAD, k);
3835 JavaValue result(T_VOID);
3836 JavaCalls::call_static(&result,
3837 shutdown_klass,
3838 vmSymbols::shutdown_method_name(),
3839 vmSymbols::void_method_signature(),
3840 THREAD);
3841 }
3842 CLEAR_PENDING_EXCEPTION;
3843 }
3844
3845 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3846 // the program falls off the end of main(). Another VM exit path is through
3847 // vm_exit() when the program calls System.exit() to return a value or when
3848 // there is a serious error in VM. The two shutdown paths are not exactly
3849 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3850 // and VM_Exit op at VM level.
3851 //
3852 // Shutdown sequence:
3853 // + Shutdown native memory tracking if it is on
3854 // + Wait until we are the last non-daemon thread to execute
3855 // <-- every thing is still working at this moment -->
3856 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3857 // shutdown hooks, run finalizers if finalization-on-exit
3858 // + Call before_exit(), prepare for VM exit
3859 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3860 // currently the only user of this mechanism is File.deleteOnExit())
3861 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3862 // post thread end and vm death events to JVMTI,
3863 // stop signal thread
3864 // + Call JavaThread::exit(), it will:
3865 // > release JNI handle blocks, remove stack guard pages
3866 // > remove this thread from Threads list
3867 // <-- no more Java code from this thread after this point -->
3868 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3869 // the compiler threads at safepoint
3870 // <-- do not use anything that could get blocked by Safepoint -->
3871 // + Disable tracing at JNI/JVM barriers
3872 // + Set _vm_exited flag for threads that are still running native code
3873 // + Delete this thread
3874 // + Call exit_globals()
3875 // > deletes tty
3876 // > deletes PerfMemory resources
3877 // + Return to caller
3878
3879 bool Threads::destroy_vm() {
3880 JavaThread* thread = JavaThread::current();
3881
3882 #ifdef ASSERT
3883 _vm_complete = false;
3884 #endif
3885 // Wait until we are the last non-daemon thread to execute
3886 { MutexLocker nu(Threads_lock);
3887 while (Threads::number_of_non_daemon_threads() > 1)
3888 // This wait should make safepoint checks, wait without a timeout,
3889 // and wait as a suspend-equivalent condition.
3890 //
3891 // Note: If the FlatProfiler is running and this thread is waiting
3892 // for another non-daemon thread to finish, then the FlatProfiler
3893 // is waiting for the external suspend request on this thread to
3894 // complete. wait_for_ext_suspend_completion() will eventually
3895 // timeout, but that takes time. Making this wait a suspend-
3896 // equivalent condition solves that timeout problem.
3897 //
3898 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3899 Mutex::_as_suspend_equivalent_flag);
3900 }
3901
3902 // Hang forever on exit if we are reporting an error.
3903 if (ShowMessageBoxOnError && is_error_reported()) {
3904 os::infinite_sleep();
3905 }
3906 os::wait_for_keypress_at_exit();
3907
3908 // run Java level shutdown hooks
3909 thread->invoke_shutdown_hooks();
3910
3911 before_exit(thread);
3912
3913 thread->exit(true);
3914
3915 // Stop VM thread.
3916 {
3917 // 4945125 The vm thread comes to a safepoint during exit.
3918 // GC vm_operations can get caught at the safepoint, and the
3919 // heap is unparseable if they are caught. Grab the Heap_lock
3920 // to prevent this. The GC vm_operations will not be able to
3921 // queue until after the vm thread is dead. After this point,
3922 // we'll never emerge out of the safepoint before the VM exits.
3923
3924 MutexLocker ml(Heap_lock);
3925
3926 VMThread::wait_for_vm_thread_exit();
3927 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3928 VMThread::destroy();
3929 }
3930
3931 // clean up ideal graph printers
3932 #if defined(COMPILER2) && !defined(PRODUCT)
3933 IdealGraphPrinter::clean_up();
3934 #endif
3935
3936 // Now, all Java threads are gone except daemon threads. Daemon threads
3937 // running Java code or in VM are stopped by the Safepoint. However,
3938 // daemon threads executing native code are still running. But they
3939 // will be stopped at native=>Java/VM barriers. Note that we can't
3940 // simply kill or suspend them, as it is inherently deadlock-prone.
3941
3942 #ifndef PRODUCT
3943 // disable function tracing at JNI/JVM barriers
3944 TraceJNICalls = false;
3945 TraceJVMCalls = false;
3946 TraceRuntimeCalls = false;
3947 #endif
3948
3949 VM_Exit::set_vm_exited();
3950
3951 notify_vm_shutdown();
3952
3953 delete thread;
3954
3955 // exit_globals() will delete tty
3956 exit_globals();
3957
3958 return true;
3959 }
3960
3961
3962 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3963 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3964 return is_supported_jni_version(version);
3965 }
3966
3967
3968 jboolean Threads::is_supported_jni_version(jint version) {
3969 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3970 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3971 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3972 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3973 return JNI_FALSE;
3974 }
3975
3976
3977 void Threads::add(JavaThread* p, bool force_daemon) {
3978 // The threads lock must be owned at this point
3979 assert_locked_or_safepoint(Threads_lock);
3980
3981 // See the comment for this method in thread.hpp for its purpose and
3982 // why it is called here.
3983 p->initialize_queues();
3984 p->set_next(_thread_list);
3985 _thread_list = p;
3986 _number_of_threads++;
3987 oop threadObj = p->threadObj();
3988 bool daemon = true;
3989 // Bootstrapping problem: threadObj can be null for initial
3990 // JavaThread (or for threads attached via JNI)
3991 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3992 _number_of_non_daemon_threads++;
3993 daemon = false;
3994 }
3995
3996 ThreadService::add_thread(p, daemon);
3997
3998 // Possible GC point.
3999 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4000 }
4001
4002 void Threads::remove(JavaThread* p) {
4003 // Extra scope needed for Thread_lock, so we can check
4004 // that we do not remove thread without safepoint code notice
4005 { MutexLocker ml(Threads_lock);
4006
4007 assert(includes(p), "p must be present");
4008
4009 JavaThread* current = _thread_list;
4010 JavaThread* prev = NULL;
4011
4012 while (current != p) {
4013 prev = current;
4014 current = current->next();
4015 }
4016
4017 if (prev) {
4018 prev->set_next(current->next());
4019 } else {
4020 _thread_list = p->next();
4021 }
4022 _number_of_threads--;
4023 oop threadObj = p->threadObj();
4024 bool daemon = true;
4025 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4026 _number_of_non_daemon_threads--;
4027 daemon = false;
4028
4029 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4030 // on destroy_vm will wake up.
4031 if (number_of_non_daemon_threads() == 1) {
4032 Threads_lock->notify_all();
4033 }
4034 }
4035 ThreadService::remove_thread(p, daemon);
4036
4037 // Make sure that safepoint code disregard this thread. This is needed since
4038 // the thread might mess around with locks after this point. This can cause it
4039 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4040 // of this thread since it is removed from the queue.
4041 p->set_terminated_value();
4042 } // unlock Threads_lock
4043
4044 // Since Events::log uses a lock, we grab it outside the Threads_lock
4045 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4046 }
4047
4048 // Threads_lock must be held when this is called (or must be called during a safepoint)
4049 bool Threads::includes(JavaThread* p) {
4050 assert(Threads_lock->is_locked(), "sanity check");
4051 ALL_JAVA_THREADS(q) {
4052 if (q == p) {
4053 return true;
4054 }
4055 }
4056 return false;
4057 }
4058
4059 // Operations on the Threads list for GC. These are not explicitly locked,
4060 // but the garbage collector must provide a safe context for them to run.
4061 // In particular, these things should never be called when the Threads_lock
4062 // is held by some other thread. (Note: the Safepoint abstraction also
4063 // uses the Threads_lock to guarantee this property. It also makes sure that
4064 // all threads gets blocked when exiting or starting).
4065
4066 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4067 ALL_JAVA_THREADS(p) {
4068 p->oops_do(f, cld_f, cf);
4069 }
4070 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4071 }
4072
4073 void Threads::change_thread_claim_parity() {
4074 // Set the new claim parity.
4075 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4076 "Not in range.");
4077 _thread_claim_parity++;
4078 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4079 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4080 "Not in range.");
4081 }
4082
4083 #ifdef ASSERT
4084 void Threads::assert_all_threads_claimed() {
4085 ALL_JAVA_THREADS(p) {
4086 const int thread_parity = p->oops_do_parity();
4087 assert((thread_parity == _thread_claim_parity),
4088 err_msg("Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity));
4089 }
4090 }
4091 #endif // ASSERT
4092
4093 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4094 int cp = Threads::thread_claim_parity();
4095 ALL_JAVA_THREADS(p) {
4096 if (p->claim_oops_do(is_par, cp)) {
4097 p->oops_do(f, cld_f, cf);
4098 }
4099 }
4100 VMThread* vmt = VMThread::vm_thread();
4101 if (vmt->claim_oops_do(is_par, cp)) {
4102 vmt->oops_do(f, cld_f, cf);
4103 }
4104 }
4105
4106 #if INCLUDE_ALL_GCS
4107 // Used by ParallelScavenge
4108 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4109 ALL_JAVA_THREADS(p) {
4110 q->enqueue(new ThreadRootsTask(p));
4111 }
4112 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4113 }
4114
4115 // Used by Parallel Old
4116 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4117 ALL_JAVA_THREADS(p) {
4118 q->enqueue(new ThreadRootsMarkingTask(p));
4119 }
4120 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4121 }
4122 #endif // INCLUDE_ALL_GCS
4123
4124 void Threads::nmethods_do(CodeBlobClosure* cf) {
4125 ALL_JAVA_THREADS(p) {
4126 p->nmethods_do(cf);
4127 }
4128 VMThread::vm_thread()->nmethods_do(cf);
4129 }
4130
4131 void Threads::metadata_do(void f(Metadata*)) {
4132 ALL_JAVA_THREADS(p) {
4133 p->metadata_do(f);
4134 }
4135 }
4136
4137 class ThreadHandlesClosure : public ThreadClosure {
4138 void (*_f)(Metadata*);
4139 public:
4140 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4141 virtual void do_thread(Thread* thread) {
4142 thread->metadata_handles_do(_f);
4143 }
4144 };
4145
4146 void Threads::metadata_handles_do(void f(Metadata*)) {
4147 // Only walk the Handles in Thread.
4148 ThreadHandlesClosure handles_closure(f);
4149 threads_do(&handles_closure);
4150 }
4151
4152 void Threads::deoptimized_wrt_marked_nmethods() {
4153 ALL_JAVA_THREADS(p) {
4154 p->deoptimized_wrt_marked_nmethods();
4155 }
4156 }
4157
4158
4159 // Get count Java threads that are waiting to enter the specified monitor.
4160 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4161 address monitor,
4162 bool doLock) {
4163 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4164 "must grab Threads_lock or be at safepoint");
4165 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4166
4167 int i = 0;
4168 {
4169 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4170 ALL_JAVA_THREADS(p) {
4171 if (p->is_Compiler_thread()) continue;
4172
4173 address pending = (address)p->current_pending_monitor();
4174 if (pending == monitor) { // found a match
4175 if (i < count) result->append(p); // save the first count matches
4176 i++;
4177 }
4178 }
4179 }
4180 return result;
4181 }
4182
4183
4184 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4185 bool doLock) {
4186 assert(doLock ||
4187 Threads_lock->owned_by_self() ||
4188 SafepointSynchronize::is_at_safepoint(),
4189 "must grab Threads_lock or be at safepoint");
4190
4191 // NULL owner means not locked so we can skip the search
4192 if (owner == NULL) return NULL;
4193
4194 {
4195 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4196 ALL_JAVA_THREADS(p) {
4197 // first, see if owner is the address of a Java thread
4198 if (owner == (address)p) return p;
4199 }
4200 }
4201 // Cannot assert on lack of success here since this function may be
4202 // used by code that is trying to report useful problem information
4203 // like deadlock detection.
4204 if (UseHeavyMonitors) return NULL;
4205
4206 // If we didn't find a matching Java thread and we didn't force use of
4207 // heavyweight monitors, then the owner is the stack address of the
4208 // Lock Word in the owning Java thread's stack.
4209 //
4210 JavaThread* the_owner = NULL;
4211 {
4212 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4213 ALL_JAVA_THREADS(q) {
4214 if (q->is_lock_owned(owner)) {
4215 the_owner = q;
4216 break;
4217 }
4218 }
4219 }
4220 // cannot assert on lack of success here; see above comment
4221 return the_owner;
4222 }
4223
4224 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4225 void Threads::print_on(outputStream* st, bool print_stacks,
4226 bool internal_format, bool print_concurrent_locks) {
4227 char buf[32];
4228 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4229
4230 st->print_cr("Full thread dump %s (%s %s):",
4231 Abstract_VM_Version::vm_name(),
4232 Abstract_VM_Version::vm_release(),
4233 Abstract_VM_Version::vm_info_string());
4234 st->cr();
4235
4236 #if INCLUDE_SERVICES
4237 // Dump concurrent locks
4238 ConcurrentLocksDump concurrent_locks;
4239 if (print_concurrent_locks) {
4240 concurrent_locks.dump_at_safepoint();
4241 }
4242 #endif // INCLUDE_SERVICES
4243
4244 ALL_JAVA_THREADS(p) {
4245 ResourceMark rm;
4246 p->print_on(st);
4247 if (print_stacks) {
4248 if (internal_format) {
4249 p->trace_stack();
4250 } else {
4251 p->print_stack_on(st);
4252 }
4253 }
4254 st->cr();
4255 #if INCLUDE_SERVICES
4256 if (print_concurrent_locks) {
4257 concurrent_locks.print_locks_on(p, st);
4258 }
4259 #endif // INCLUDE_SERVICES
4260 }
4261
4262 VMThread::vm_thread()->print_on(st);
4263 st->cr();
4264 Universe::heap()->print_gc_threads_on(st);
4265 WatcherThread* wt = WatcherThread::watcher_thread();
4266 if (wt != NULL) {
4267 wt->print_on(st);
4268 st->cr();
4269 }
4270 CompileBroker::print_compiler_threads_on(st);
4271 st->flush();
4272 }
4273
4274 // Threads::print_on_error() is called by fatal error handler. It's possible
4275 // that VM is not at safepoint and/or current thread is inside signal handler.
4276 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4277 // memory (even in resource area), it might deadlock the error handler.
4278 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4279 int buflen) {
4280 bool found_current = false;
4281 st->print_cr("Java Threads: ( => current thread )");
4282 ALL_JAVA_THREADS(thread) {
4283 bool is_current = (current == thread);
4284 found_current = found_current || is_current;
4285
4286 st->print("%s", is_current ? "=>" : " ");
4287
4288 st->print(PTR_FORMAT, thread);
4289 st->print(" ");
4290 thread->print_on_error(st, buf, buflen);
4291 st->cr();
4292 }
4293 st->cr();
4294
4295 st->print_cr("Other Threads:");
4296 if (VMThread::vm_thread()) {
4297 bool is_current = (current == VMThread::vm_thread());
4298 found_current = found_current || is_current;
4299 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4300
4301 st->print(PTR_FORMAT, VMThread::vm_thread());
4302 st->print(" ");
4303 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4304 st->cr();
4305 }
4306 WatcherThread* wt = WatcherThread::watcher_thread();
4307 if (wt != NULL) {
4308 bool is_current = (current == wt);
4309 found_current = found_current || is_current;
4310 st->print("%s", is_current ? "=>" : " ");
4311
4312 st->print(PTR_FORMAT, wt);
4313 st->print(" ");
4314 wt->print_on_error(st, buf, buflen);
4315 st->cr();
4316 }
4317 if (!found_current) {
4318 st->cr();
4319 st->print("=>" PTR_FORMAT " (exited) ", current);
4320 current->print_on_error(st, buf, buflen);
4321 st->cr();
4322 }
4323 }
4324
4325 // Internal SpinLock and Mutex
4326 // Based on ParkEvent
4327
4328 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4329 //
4330 // We employ SpinLocks _only for low-contention, fixed-length
4331 // short-duration critical sections where we're concerned
4332 // about native mutex_t or HotSpot Mutex:: latency.
4333 // The mux construct provides a spin-then-block mutual exclusion
4334 // mechanism.
4335 //
4336 // Testing has shown that contention on the ListLock guarding gFreeList
4337 // is common. If we implement ListLock as a simple SpinLock it's common
4338 // for the JVM to devolve to yielding with little progress. This is true
4339 // despite the fact that the critical sections protected by ListLock are
4340 // extremely short.
4341 //
4342 // TODO-FIXME: ListLock should be of type SpinLock.
4343 // We should make this a 1st-class type, integrated into the lock
4344 // hierarchy as leaf-locks. Critically, the SpinLock structure
4345 // should have sufficient padding to avoid false-sharing and excessive
4346 // cache-coherency traffic.
4347
4348
4349 typedef volatile int SpinLockT;
4350
4351 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4352 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4353 return; // normal fast-path return
4354 }
4355
4356 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4357 TEVENT(SpinAcquire - ctx);
4358 int ctr = 0;
4359 int Yields = 0;
4360 for (;;) {
4361 while (*adr != 0) {
4362 ++ctr;
4363 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4364 if (Yields > 5) {
4365 os::naked_short_sleep(1);
4366 } else {
4367 os::naked_yield();
4368 ++Yields;
4369 }
4370 } else {
4371 SpinPause();
4372 }
4373 }
4374 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4375 }
4376 }
4377
4378 void Thread::SpinRelease(volatile int * adr) {
4379 assert(*adr != 0, "invariant");
4380 OrderAccess::fence(); // guarantee at least release consistency.
4381 // Roach-motel semantics.
4382 // It's safe if subsequent LDs and STs float "up" into the critical section,
4383 // but prior LDs and STs within the critical section can't be allowed
4384 // to reorder or float past the ST that releases the lock.
4385 // Loads and stores in the critical section - which appear in program
4386 // order before the store that releases the lock - must also appear
4387 // before the store that releases the lock in memory visibility order.
4388 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4389 // the ST of 0 into the lock-word which releases the lock, so fence
4390 // more than covers this on all platforms.
4391 *adr = 0;
4392 }
4393
4394 // muxAcquire and muxRelease:
4395 //
4396 // * muxAcquire and muxRelease support a single-word lock-word construct.
4397 // The LSB of the word is set IFF the lock is held.
4398 // The remainder of the word points to the head of a singly-linked list
4399 // of threads blocked on the lock.
4400 //
4401 // * The current implementation of muxAcquire-muxRelease uses its own
4402 // dedicated Thread._MuxEvent instance. If we're interested in
4403 // minimizing the peak number of extant ParkEvent instances then
4404 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4405 // as certain invariants were satisfied. Specifically, care would need
4406 // to be taken with regards to consuming unpark() "permits".
4407 // A safe rule of thumb is that a thread would never call muxAcquire()
4408 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4409 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4410 // consume an unpark() permit intended for monitorenter, for instance.
4411 // One way around this would be to widen the restricted-range semaphore
4412 // implemented in park(). Another alternative would be to provide
4413 // multiple instances of the PlatformEvent() for each thread. One
4414 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4415 //
4416 // * Usage:
4417 // -- Only as leaf locks
4418 // -- for short-term locking only as muxAcquire does not perform
4419 // thread state transitions.
4420 //
4421 // Alternatives:
4422 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4423 // but with parking or spin-then-park instead of pure spinning.
4424 // * Use Taura-Oyama-Yonenzawa locks.
4425 // * It's possible to construct a 1-0 lock if we encode the lockword as
4426 // (List,LockByte). Acquire will CAS the full lockword while Release
4427 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4428 // acquiring threads use timers (ParkTimed) to detect and recover from
4429 // the stranding window. Thread/Node structures must be aligned on 256-byte
4430 // boundaries by using placement-new.
4431 // * Augment MCS with advisory back-link fields maintained with CAS().
4432 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4433 // The validity of the backlinks must be ratified before we trust the value.
4434 // If the backlinks are invalid the exiting thread must back-track through the
4435 // the forward links, which are always trustworthy.
4436 // * Add a successor indication. The LockWord is currently encoded as
4437 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4438 // to provide the usual futile-wakeup optimization.
4439 // See RTStt for details.
4440 // * Consider schedctl.sc_nopreempt to cover the critical section.
4441 //
4442
4443
4444 typedef volatile intptr_t MutexT; // Mux Lock-word
4445 enum MuxBits { LOCKBIT = 1 };
4446
4447 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4448 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4449 if (w == 0) return;
4450 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4451 return;
4452 }
4453
4454 TEVENT(muxAcquire - Contention);
4455 ParkEvent * const Self = Thread::current()->_MuxEvent;
4456 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4457 for (;;) {
4458 int its = (os::is_MP() ? 100 : 0) + 1;
4459
4460 // Optional spin phase: spin-then-park strategy
4461 while (--its >= 0) {
4462 w = *Lock;
4463 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4464 return;
4465 }
4466 }
4467
4468 Self->reset();
4469 Self->OnList = intptr_t(Lock);
4470 // The following fence() isn't _strictly necessary as the subsequent
4471 // CAS() both serializes execution and ratifies the fetched *Lock value.
4472 OrderAccess::fence();
4473 for (;;) {
4474 w = *Lock;
4475 if ((w & LOCKBIT) == 0) {
4476 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4477 Self->OnList = 0; // hygiene - allows stronger asserts
4478 return;
4479 }
4480 continue; // Interference -- *Lock changed -- Just retry
4481 }
4482 assert(w & LOCKBIT, "invariant");
4483 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4484 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4485 }
4486
4487 while (Self->OnList != 0) {
4488 Self->park();
4489 }
4490 }
4491 }
4492
4493 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4494 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4495 if (w == 0) return;
4496 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4497 return;
4498 }
4499
4500 TEVENT(muxAcquire - Contention);
4501 ParkEvent * ReleaseAfter = NULL;
4502 if (ev == NULL) {
4503 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4504 }
4505 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4506 for (;;) {
4507 guarantee(ev->OnList == 0, "invariant");
4508 int its = (os::is_MP() ? 100 : 0) + 1;
4509
4510 // Optional spin phase: spin-then-park strategy
4511 while (--its >= 0) {
4512 w = *Lock;
4513 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4514 if (ReleaseAfter != NULL) {
4515 ParkEvent::Release(ReleaseAfter);
4516 }
4517 return;
4518 }
4519 }
4520
4521 ev->reset();
4522 ev->OnList = intptr_t(Lock);
4523 // The following fence() isn't _strictly necessary as the subsequent
4524 // CAS() both serializes execution and ratifies the fetched *Lock value.
4525 OrderAccess::fence();
4526 for (;;) {
4527 w = *Lock;
4528 if ((w & LOCKBIT) == 0) {
4529 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4530 ev->OnList = 0;
4531 // We call ::Release while holding the outer lock, thus
4532 // artificially lengthening the critical section.
4533 // Consider deferring the ::Release() until the subsequent unlock(),
4534 // after we've dropped the outer lock.
4535 if (ReleaseAfter != NULL) {
4536 ParkEvent::Release(ReleaseAfter);
4537 }
4538 return;
4539 }
4540 continue; // Interference -- *Lock changed -- Just retry
4541 }
4542 assert(w & LOCKBIT, "invariant");
4543 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4544 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4545 }
4546
4547 while (ev->OnList != 0) {
4548 ev->park();
4549 }
4550 }
4551 }
4552
4553 // Release() must extract a successor from the list and then wake that thread.
4554 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4555 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4556 // Release() would :
4557 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4558 // (B) Extract a successor from the private list "in-hand"
4559 // (C) attempt to CAS() the residual back into *Lock over null.
4560 // If there were any newly arrived threads and the CAS() would fail.
4561 // In that case Release() would detach the RATs, re-merge the list in-hand
4562 // with the RATs and repeat as needed. Alternately, Release() might
4563 // detach and extract a successor, but then pass the residual list to the wakee.
4564 // The wakee would be responsible for reattaching and remerging before it
4565 // competed for the lock.
4566 //
4567 // Both "pop" and DMR are immune from ABA corruption -- there can be
4568 // multiple concurrent pushers, but only one popper or detacher.
4569 // This implementation pops from the head of the list. This is unfair,
4570 // but tends to provide excellent throughput as hot threads remain hot.
4571 // (We wake recently run threads first).
4572 //
4573 // All paths through muxRelease() will execute a CAS.
4574 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4575 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4576 // executed within the critical section are complete and globally visible before the
4577 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4578 void Thread::muxRelease(volatile intptr_t * Lock) {
4579 for (;;) {
4580 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4581 assert(w & LOCKBIT, "invariant");
4582 if (w == LOCKBIT) return;
4583 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4584 assert(List != NULL, "invariant");
4585 assert(List->OnList == intptr_t(Lock), "invariant");
4586 ParkEvent * const nxt = List->ListNext;
4587 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4588
4589 // The following CAS() releases the lock and pops the head element.
4590 // The CAS() also ratifies the previously fetched lock-word value.
4591 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4592 continue;
4593 }
4594 List->OnList = 0;
4595 OrderAccess::fence();
4596 List->unpark();
4597 return;
4598 }
4599 }
4600
4601
4602 void Threads::verify() {
4603 ALL_JAVA_THREADS(p) {
4604 p->verify();
4605 }
4606 VMThread* thread = VMThread::vm_thread();
4607 if (thread != NULL) thread->verify();
4608 }