1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/scopeDesc.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "interpreter/linkResolver.hpp"
35 #include "interpreter/oopMapCache.hpp"
36 #include "jvmtifiles/jvmtiEnv.hpp"
37 #include "memory/gcLocker.inline.hpp"
38 #include "memory/metaspaceShared.hpp"
39 #include "memory/oopFactory.hpp"
40 #include "memory/universe.inline.hpp"
41 #include "oops/instanceKlass.hpp"
42 #include "oops/objArrayOop.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "oops/symbol.hpp"
45 #include "prims/jvm_misc.hpp"
46 #include "prims/jvmtiExport.hpp"
47 #include "prims/jvmtiThreadState.hpp"
48 #include "prims/privilegedStack.hpp"
49 #include "runtime/arguments.hpp"
50 #include "runtime/atomic.inline.hpp"
51 #include "runtime/biasedLocking.hpp"
52 #include "runtime/deoptimization.hpp"
53 #include "runtime/fprofiler.hpp"
54 #include "runtime/frame.inline.hpp"
55 #include "runtime/init.hpp"
56 #include "runtime/interfaceSupport.hpp"
57 #include "runtime/java.hpp"
58 #include "runtime/javaCalls.hpp"
59 #include "runtime/jniPeriodicChecker.hpp"
60 #include "runtime/memprofiler.hpp"
61 #include "runtime/mutexLocker.hpp"
62 #include "runtime/objectMonitor.hpp"
63 #include "runtime/orderAccess.inline.hpp"
64 #include "runtime/osThread.hpp"
65 #include "runtime/safepoint.hpp"
66 #include "runtime/sharedRuntime.hpp"
67 #include "runtime/statSampler.hpp"
68 #include "runtime/stubRoutines.hpp"
69 #include "runtime/task.hpp"
70 #include "runtime/thread.inline.hpp"
71 #include "runtime/threadCritical.hpp"
72 #include "runtime/threadLocalStorage.hpp"
73 #include "runtime/vframe.hpp"
74 #include "runtime/vframeArray.hpp"
75 #include "runtime/vframe_hp.hpp"
76 #include "runtime/vmThread.hpp"
77 #include "runtime/vm_operations.hpp"
78 #include "runtime/vm_version.hpp"
79 #include "services/attachListener.hpp"
80 #include "services/management.hpp"
81 #include "services/memTracker.hpp"
82 #include "services/threadService.hpp"
83 #include "trace/tracing.hpp"
84 #include "trace/traceMacros.hpp"
85 #include "utilities/defaultStream.hpp"
86 #include "utilities/dtrace.hpp"
87 #include "utilities/events.hpp"
88 #include "utilities/preserveException.hpp"
89 #include "utilities/macros.hpp"
90 #if INCLUDE_ALL_GCS
91 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
92 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
93 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
94 #endif // INCLUDE_ALL_GCS
95 #ifdef COMPILER1
96 #include "c1/c1_Compiler.hpp"
97 #endif
98 #ifdef COMPILER2
99 #include "opto/c2compiler.hpp"
100 #include "opto/idealGraphPrinter.hpp"
101 #endif
102 #if INCLUDE_RTM_OPT
103 #include "runtime/rtmLocking.hpp"
104 #endif
105
106 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
107
108 #ifdef DTRACE_ENABLED
109
110 // Only bother with this argument setup if dtrace is available
111
112 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
113 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
114
115 #define DTRACE_THREAD_PROBE(probe, javathread) \
116 { \
117 ResourceMark rm(this); \
118 int len = 0; \
119 const char* name = (javathread)->get_thread_name(); \
120 len = strlen(name); \
121 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
122 (char *) name, len, \
123 java_lang_Thread::thread_id((javathread)->threadObj()), \
124 (uintptr_t) (javathread)->osthread()->thread_id(), \
125 java_lang_Thread::is_daemon((javathread)->threadObj())); \
126 }
127
128 #else // ndef DTRACE_ENABLED
129
130 #define DTRACE_THREAD_PROBE(probe, javathread)
131
132 #endif // ndef DTRACE_ENABLED
133
134
135 // Class hierarchy
136 // - Thread
137 // - VMThread
138 // - WatcherThread
139 // - ConcurrentMarkSweepThread
140 // - JavaThread
141 // - CompilerThread
142
143 // ======= Thread ========
144 // Support for forcing alignment of thread objects for biased locking
145 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
146 if (UseBiasedLocking) {
147 const int alignment = markOopDesc::biased_lock_alignment;
148 size_t aligned_size = size + (alignment - sizeof(intptr_t));
149 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
150 : AllocateHeap(aligned_size, flags, CURRENT_PC,
151 AllocFailStrategy::RETURN_NULL);
152 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
153 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
154 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
155 "JavaThread alignment code overflowed allocated storage");
156 if (TraceBiasedLocking) {
157 if (aligned_addr != real_malloc_addr) {
158 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
159 real_malloc_addr, aligned_addr);
160 }
161 }
162 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
163 return aligned_addr;
164 } else {
165 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
166 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
167 }
168 }
169
170 void Thread::operator delete(void* p) {
171 if (UseBiasedLocking) {
172 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
173 FreeHeap(real_malloc_addr, mtThread);
174 } else {
175 FreeHeap(p, mtThread);
176 }
177 }
178
179
180 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
181 // JavaThread
182
183
184 Thread::Thread() {
185 // stack and get_thread
186 set_stack_base(NULL);
187 set_stack_size(0);
188 set_self_raw_id(0);
189 set_lgrp_id(-1);
190
191 // allocated data structures
192 set_osthread(NULL);
193 set_resource_area(new (mtThread)ResourceArea());
194 DEBUG_ONLY(_current_resource_mark = NULL;)
195 set_handle_area(new (mtThread) HandleArea(NULL));
196 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
197 set_active_handles(NULL);
198 set_free_handle_block(NULL);
199 set_last_handle_mark(NULL);
200
201 // This initial value ==> never claimed.
202 _oops_do_parity = 0;
203
204 // the handle mark links itself to last_handle_mark
205 new HandleMark(this);
206
207 // plain initialization
208 debug_only(_owned_locks = NULL;)
209 debug_only(_allow_allocation_count = 0;)
210 NOT_PRODUCT(_allow_safepoint_count = 0;)
211 NOT_PRODUCT(_skip_gcalot = false;)
212 _jvmti_env_iteration_count = 0;
213 set_allocated_bytes(0);
214 _vm_operation_started_count = 0;
215 _vm_operation_completed_count = 0;
216 _current_pending_monitor = NULL;
217 _current_pending_monitor_is_from_java = true;
218 _current_waiting_monitor = NULL;
219 _num_nested_signal = 0;
220 omFreeList = NULL;
221 omFreeCount = 0;
222 omFreeProvision = 32;
223 omInUseList = NULL;
224 omInUseCount = 0;
225
226 #ifdef ASSERT
227 _visited_for_critical_count = false;
228 #endif
229
230 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
231 _suspend_flags = 0;
232
233 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
234 _hashStateX = os::random();
235 _hashStateY = 842502087;
236 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
237 _hashStateW = 273326509;
238
239 _OnTrap = 0;
240 _schedctl = NULL;
241 _Stalled = 0;
242 _TypeTag = 0x2BAD;
243
244 // Many of the following fields are effectively final - immutable
245 // Note that nascent threads can't use the Native Monitor-Mutex
246 // construct until the _MutexEvent is initialized ...
247 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
248 // we might instead use a stack of ParkEvents that we could provision on-demand.
249 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
250 // and ::Release()
251 _ParkEvent = ParkEvent::Allocate(this);
252 _SleepEvent = ParkEvent::Allocate(this);
253 _MutexEvent = ParkEvent::Allocate(this);
254 _MuxEvent = ParkEvent::Allocate(this);
255
256 #ifdef CHECK_UNHANDLED_OOPS
257 if (CheckUnhandledOops) {
258 _unhandled_oops = new UnhandledOops(this);
259 }
260 #endif // CHECK_UNHANDLED_OOPS
261 #ifdef ASSERT
262 if (UseBiasedLocking) {
263 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
264 assert(this == _real_malloc_address ||
265 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
266 "bug in forced alignment of thread objects");
267 }
268 #endif // ASSERT
269 }
270
271 void Thread::initialize_thread_local_storage() {
272 // Note: Make sure this method only calls
273 // non-blocking operations. Otherwise, it might not work
274 // with the thread-startup/safepoint interaction.
275
276 // During Java thread startup, safepoint code should allow this
277 // method to complete because it may need to allocate memory to
278 // store information for the new thread.
279
280 // initialize structure dependent on thread local storage
281 ThreadLocalStorage::set_thread(this);
282 }
283
284 void Thread::record_stack_base_and_size() {
285 set_stack_base(os::current_stack_base());
286 set_stack_size(os::current_stack_size());
287 if (is_Java_thread()) {
288 ((JavaThread*) this)->set_stack_overflow_limit();
289 }
290 // CR 7190089: on Solaris, primordial thread's stack is adjusted
291 // in initialize_thread(). Without the adjustment, stack size is
292 // incorrect if stack is set to unlimited (ulimit -s unlimited).
293 // So far, only Solaris has real implementation of initialize_thread().
294 //
295 // set up any platform-specific state.
296 os::initialize_thread(this);
297
298 #if INCLUDE_NMT
299 // record thread's native stack, stack grows downward
300 address stack_low_addr = stack_base() - stack_size();
301 MemTracker::record_thread_stack(stack_low_addr, stack_size());
302 #endif // INCLUDE_NMT
303 }
304
305
306 Thread::~Thread() {
307 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
308 ObjectSynchronizer::omFlush(this);
309
310 EVENT_THREAD_DESTRUCT(this);
311
312 // stack_base can be NULL if the thread is never started or exited before
313 // record_stack_base_and_size called. Although, we would like to ensure
314 // that all started threads do call record_stack_base_and_size(), there is
315 // not proper way to enforce that.
316 #if INCLUDE_NMT
317 if (_stack_base != NULL) {
318 address low_stack_addr = stack_base() - stack_size();
319 MemTracker::release_thread_stack(low_stack_addr, stack_size());
320 #ifdef ASSERT
321 set_stack_base(NULL);
322 #endif
323 }
324 #endif // INCLUDE_NMT
325
326 // deallocate data structures
327 delete resource_area();
328 // since the handle marks are using the handle area, we have to deallocated the root
329 // handle mark before deallocating the thread's handle area,
330 assert(last_handle_mark() != NULL, "check we have an element");
331 delete last_handle_mark();
332 assert(last_handle_mark() == NULL, "check we have reached the end");
333
334 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
335 // We NULL out the fields for good hygiene.
336 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
337 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
338 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
339 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
340
341 delete handle_area();
342 delete metadata_handles();
343
344 // osthread() can be NULL, if creation of thread failed.
345 if (osthread() != NULL) os::free_thread(osthread());
346
347 delete _SR_lock;
348
349 // clear thread local storage if the Thread is deleting itself
350 if (this == Thread::current()) {
351 ThreadLocalStorage::set_thread(NULL);
352 } else {
353 // In the case where we're not the current thread, invalidate all the
354 // caches in case some code tries to get the current thread or the
355 // thread that was destroyed, and gets stale information.
356 ThreadLocalStorage::invalidate_all();
357 }
358 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
359 }
360
361 // NOTE: dummy function for assertion purpose.
362 void Thread::run() {
363 ShouldNotReachHere();
364 }
365
366 #ifdef ASSERT
367 // Private method to check for dangling thread pointer
368 void check_for_dangling_thread_pointer(Thread *thread) {
369 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
370 "possibility of dangling Thread pointer");
371 }
372 #endif
373
374
375 #ifndef PRODUCT
376 // Tracing method for basic thread operations
377 void Thread::trace(const char* msg, const Thread* const thread) {
378 if (!TraceThreadEvents) return;
379 ResourceMark rm;
380 ThreadCritical tc;
381 const char *name = "non-Java thread";
382 int prio = -1;
383 if (thread->is_Java_thread()
384 && !thread->is_Compiler_thread()) {
385 // The Threads_lock must be held to get information about
386 // this thread but may not be in some situations when
387 // tracing thread events.
388 bool release_Threads_lock = false;
389 if (!Threads_lock->owned_by_self()) {
390 Threads_lock->lock();
391 release_Threads_lock = true;
392 }
393 JavaThread* jt = (JavaThread *)thread;
394 name = (char *)jt->get_thread_name();
395 oop thread_oop = jt->threadObj();
396 if (thread_oop != NULL) {
397 prio = java_lang_Thread::priority(thread_oop);
398 }
399 if (release_Threads_lock) {
400 Threads_lock->unlock();
401 }
402 }
403 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
404 }
405 #endif
406
407
408 ThreadPriority Thread::get_priority(const Thread* const thread) {
409 trace("get priority", thread);
410 ThreadPriority priority;
411 // Can return an error!
412 (void)os::get_priority(thread, priority);
413 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
414 return priority;
415 }
416
417 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
418 trace("set priority", thread);
419 debug_only(check_for_dangling_thread_pointer(thread);)
420 // Can return an error!
421 (void)os::set_priority(thread, priority);
422 }
423
424
425 void Thread::start(Thread* thread) {
426 trace("start", thread);
427 // Start is different from resume in that its safety is guaranteed by context or
428 // being called from a Java method synchronized on the Thread object.
429 if (!DisableStartThread) {
430 if (thread->is_Java_thread()) {
431 // Initialize the thread state to RUNNABLE before starting this thread.
432 // Can not set it after the thread started because we do not know the
433 // exact thread state at that time. It could be in MONITOR_WAIT or
434 // in SLEEPING or some other state.
435 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
436 java_lang_Thread::RUNNABLE);
437 }
438 os::start_thread(thread);
439 }
440 }
441
442 // Enqueue a VM_Operation to do the job for us - sometime later
443 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
444 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
445 VMThread::execute(vm_stop);
446 }
447
448
449 // Check if an external suspend request has completed (or has been
450 // cancelled). Returns true if the thread is externally suspended and
451 // false otherwise.
452 //
453 // The bits parameter returns information about the code path through
454 // the routine. Useful for debugging:
455 //
456 // set in is_ext_suspend_completed():
457 // 0x00000001 - routine was entered
458 // 0x00000010 - routine return false at end
459 // 0x00000100 - thread exited (return false)
460 // 0x00000200 - suspend request cancelled (return false)
461 // 0x00000400 - thread suspended (return true)
462 // 0x00001000 - thread is in a suspend equivalent state (return true)
463 // 0x00002000 - thread is native and walkable (return true)
464 // 0x00004000 - thread is native_trans and walkable (needed retry)
465 //
466 // set in wait_for_ext_suspend_completion():
467 // 0x00010000 - routine was entered
468 // 0x00020000 - suspend request cancelled before loop (return false)
469 // 0x00040000 - thread suspended before loop (return true)
470 // 0x00080000 - suspend request cancelled in loop (return false)
471 // 0x00100000 - thread suspended in loop (return true)
472 // 0x00200000 - suspend not completed during retry loop (return false)
473
474 // Helper class for tracing suspend wait debug bits.
475 //
476 // 0x00000100 indicates that the target thread exited before it could
477 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
478 // 0x00080000 each indicate a cancelled suspend request so they don't
479 // count as wait failures either.
480 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
481
482 class TraceSuspendDebugBits : public StackObj {
483 private:
484 JavaThread * jt;
485 bool is_wait;
486 bool called_by_wait; // meaningful when !is_wait
487 uint32_t * bits;
488
489 public:
490 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
491 uint32_t *_bits) {
492 jt = _jt;
493 is_wait = _is_wait;
494 called_by_wait = _called_by_wait;
495 bits = _bits;
496 }
497
498 ~TraceSuspendDebugBits() {
499 if (!is_wait) {
500 #if 1
501 // By default, don't trace bits for is_ext_suspend_completed() calls.
502 // That trace is very chatty.
503 return;
504 #else
505 if (!called_by_wait) {
506 // If tracing for is_ext_suspend_completed() is enabled, then only
507 // trace calls to it from wait_for_ext_suspend_completion()
508 return;
509 }
510 #endif
511 }
512
513 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
514 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
515 MutexLocker ml(Threads_lock); // needed for get_thread_name()
516 ResourceMark rm;
517
518 tty->print_cr(
519 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
520 jt->get_thread_name(), *bits);
521
522 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
523 }
524 }
525 }
526 };
527 #undef DEBUG_FALSE_BITS
528
529
530 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
531 uint32_t *bits) {
532 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
533
534 bool did_trans_retry = false; // only do thread_in_native_trans retry once
535 bool do_trans_retry; // flag to force the retry
536
537 *bits |= 0x00000001;
538
539 do {
540 do_trans_retry = false;
541
542 if (is_exiting()) {
543 // Thread is in the process of exiting. This is always checked
544 // first to reduce the risk of dereferencing a freed JavaThread.
545 *bits |= 0x00000100;
546 return false;
547 }
548
549 if (!is_external_suspend()) {
550 // Suspend request is cancelled. This is always checked before
551 // is_ext_suspended() to reduce the risk of a rogue resume
552 // confusing the thread that made the suspend request.
553 *bits |= 0x00000200;
554 return false;
555 }
556
557 if (is_ext_suspended()) {
558 // thread is suspended
559 *bits |= 0x00000400;
560 return true;
561 }
562
563 // Now that we no longer do hard suspends of threads running
564 // native code, the target thread can be changing thread state
565 // while we are in this routine:
566 //
567 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
568 //
569 // We save a copy of the thread state as observed at this moment
570 // and make our decision about suspend completeness based on the
571 // copy. This closes the race where the thread state is seen as
572 // _thread_in_native_trans in the if-thread_blocked check, but is
573 // seen as _thread_blocked in if-thread_in_native_trans check.
574 JavaThreadState save_state = thread_state();
575
576 if (save_state == _thread_blocked && is_suspend_equivalent()) {
577 // If the thread's state is _thread_blocked and this blocking
578 // condition is known to be equivalent to a suspend, then we can
579 // consider the thread to be externally suspended. This means that
580 // the code that sets _thread_blocked has been modified to do
581 // self-suspension if the blocking condition releases. We also
582 // used to check for CONDVAR_WAIT here, but that is now covered by
583 // the _thread_blocked with self-suspension check.
584 //
585 // Return true since we wouldn't be here unless there was still an
586 // external suspend request.
587 *bits |= 0x00001000;
588 return true;
589 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
590 // Threads running native code will self-suspend on native==>VM/Java
591 // transitions. If its stack is walkable (should always be the case
592 // unless this function is called before the actual java_suspend()
593 // call), then the wait is done.
594 *bits |= 0x00002000;
595 return true;
596 } else if (!called_by_wait && !did_trans_retry &&
597 save_state == _thread_in_native_trans &&
598 frame_anchor()->walkable()) {
599 // The thread is transitioning from thread_in_native to another
600 // thread state. check_safepoint_and_suspend_for_native_trans()
601 // will force the thread to self-suspend. If it hasn't gotten
602 // there yet we may have caught the thread in-between the native
603 // code check above and the self-suspend. Lucky us. If we were
604 // called by wait_for_ext_suspend_completion(), then it
605 // will be doing the retries so we don't have to.
606 //
607 // Since we use the saved thread state in the if-statement above,
608 // there is a chance that the thread has already transitioned to
609 // _thread_blocked by the time we get here. In that case, we will
610 // make a single unnecessary pass through the logic below. This
611 // doesn't hurt anything since we still do the trans retry.
612
613 *bits |= 0x00004000;
614
615 // Once the thread leaves thread_in_native_trans for another
616 // thread state, we break out of this retry loop. We shouldn't
617 // need this flag to prevent us from getting back here, but
618 // sometimes paranoia is good.
619 did_trans_retry = true;
620
621 // We wait for the thread to transition to a more usable state.
622 for (int i = 1; i <= SuspendRetryCount; i++) {
623 // We used to do an "os::yield_all(i)" call here with the intention
624 // that yielding would increase on each retry. However, the parameter
625 // is ignored on Linux which means the yield didn't scale up. Waiting
626 // on the SR_lock below provides a much more predictable scale up for
627 // the delay. It also provides a simple/direct point to check for any
628 // safepoint requests from the VMThread
629
630 // temporarily drops SR_lock while doing wait with safepoint check
631 // (if we're a JavaThread - the WatcherThread can also call this)
632 // and increase delay with each retry
633 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
634
635 // check the actual thread state instead of what we saved above
636 if (thread_state() != _thread_in_native_trans) {
637 // the thread has transitioned to another thread state so
638 // try all the checks (except this one) one more time.
639 do_trans_retry = true;
640 break;
641 }
642 } // end retry loop
643
644
645 }
646 } while (do_trans_retry);
647
648 *bits |= 0x00000010;
649 return false;
650 }
651
652 // Wait for an external suspend request to complete (or be cancelled).
653 // Returns true if the thread is externally suspended and false otherwise.
654 //
655 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
656 uint32_t *bits) {
657 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
658 false /* !called_by_wait */, bits);
659
660 // local flag copies to minimize SR_lock hold time
661 bool is_suspended;
662 bool pending;
663 uint32_t reset_bits;
664
665 // set a marker so is_ext_suspend_completed() knows we are the caller
666 *bits |= 0x00010000;
667
668 // We use reset_bits to reinitialize the bits value at the top of
669 // each retry loop. This allows the caller to make use of any
670 // unused bits for their own marking purposes.
671 reset_bits = *bits;
672
673 {
674 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
675 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
676 delay, bits);
677 pending = is_external_suspend();
678 }
679 // must release SR_lock to allow suspension to complete
680
681 if (!pending) {
682 // A cancelled suspend request is the only false return from
683 // is_ext_suspend_completed() that keeps us from entering the
684 // retry loop.
685 *bits |= 0x00020000;
686 return false;
687 }
688
689 if (is_suspended) {
690 *bits |= 0x00040000;
691 return true;
692 }
693
694 for (int i = 1; i <= retries; i++) {
695 *bits = reset_bits; // reinit to only track last retry
696
697 // We used to do an "os::yield_all(i)" call here with the intention
698 // that yielding would increase on each retry. However, the parameter
699 // is ignored on Linux which means the yield didn't scale up. Waiting
700 // on the SR_lock below provides a much more predictable scale up for
701 // the delay. It also provides a simple/direct point to check for any
702 // safepoint requests from the VMThread
703
704 {
705 MutexLocker ml(SR_lock());
706 // wait with safepoint check (if we're a JavaThread - the WatcherThread
707 // can also call this) and increase delay with each retry
708 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
709
710 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
711 delay, bits);
712
713 // It is possible for the external suspend request to be cancelled
714 // (by a resume) before the actual suspend operation is completed.
715 // Refresh our local copy to see if we still need to wait.
716 pending = is_external_suspend();
717 }
718
719 if (!pending) {
720 // A cancelled suspend request is the only false return from
721 // is_ext_suspend_completed() that keeps us from staying in the
722 // retry loop.
723 *bits |= 0x00080000;
724 return false;
725 }
726
727 if (is_suspended) {
728 *bits |= 0x00100000;
729 return true;
730 }
731 } // end retry loop
732
733 // thread did not suspend after all our retries
734 *bits |= 0x00200000;
735 return false;
736 }
737
738 #ifndef PRODUCT
739 void JavaThread::record_jump(address target, address instr, const char* file,
740 int line) {
741
742 // This should not need to be atomic as the only way for simultaneous
743 // updates is via interrupts. Even then this should be rare or non-existent
744 // and we don't care that much anyway.
745
746 int index = _jmp_ring_index;
747 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
748 _jmp_ring[index]._target = (intptr_t) target;
749 _jmp_ring[index]._instruction = (intptr_t) instr;
750 _jmp_ring[index]._file = file;
751 _jmp_ring[index]._line = line;
752 }
753 #endif // PRODUCT
754
755 // Called by flat profiler
756 // Callers have already called wait_for_ext_suspend_completion
757 // The assertion for that is currently too complex to put here:
758 bool JavaThread::profile_last_Java_frame(frame* _fr) {
759 bool gotframe = false;
760 // self suspension saves needed state.
761 if (has_last_Java_frame() && _anchor.walkable()) {
762 *_fr = pd_last_frame();
763 gotframe = true;
764 }
765 return gotframe;
766 }
767
768 void Thread::interrupt(Thread* thread) {
769 trace("interrupt", thread);
770 debug_only(check_for_dangling_thread_pointer(thread);)
771 os::interrupt(thread);
772 }
773
774 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
775 trace("is_interrupted", thread);
776 debug_only(check_for_dangling_thread_pointer(thread);)
777 // Note: If clear_interrupted==false, this simply fetches and
778 // returns the value of the field osthread()->interrupted().
779 return os::is_interrupted(thread, clear_interrupted);
780 }
781
782
783 // GC Support
784 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
785 jint thread_parity = _oops_do_parity;
786 if (thread_parity != strong_roots_parity) {
787 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
788 if (res == thread_parity) {
789 return true;
790 } else {
791 guarantee(res == strong_roots_parity, "Or else what?");
792 assert(SharedHeap::heap()->workers()->active_workers() > 0,
793 "Should only fail when parallel.");
794 return false;
795 }
796 }
797 assert(SharedHeap::heap()->workers()->active_workers() > 0,
798 "Should only fail when parallel.");
799 return false;
800 }
801
802 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
803 active_handles()->oops_do(f);
804 // Do oop for ThreadShadow
805 f->do_oop((oop*)&_pending_exception);
806 handle_area()->oops_do(f);
807 }
808
809 void Thread::nmethods_do(CodeBlobClosure* cf) {
810 // no nmethods in a generic thread...
811 }
812
813 void Thread::metadata_do(void f(Metadata*)) {
814 if (metadata_handles() != NULL) {
815 for (int i = 0; i< metadata_handles()->length(); i++) {
816 f(metadata_handles()->at(i));
817 }
818 }
819 }
820
821 void Thread::print_on(outputStream* st) const {
822 // get_priority assumes osthread initialized
823 if (osthread() != NULL) {
824 int os_prio;
825 if (os::get_native_priority(this, &os_prio) == OS_OK) {
826 st->print("os_prio=%d ", os_prio);
827 }
828 st->print("tid=" INTPTR_FORMAT " ", this);
829 ext().print_on(st);
830 osthread()->print_on(st);
831 }
832 debug_only(if (WizardMode) print_owned_locks_on(st);)
833 }
834
835 // Thread::print_on_error() is called by fatal error handler. Don't use
836 // any lock or allocate memory.
837 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
838 if (is_VM_thread()) st->print("VMThread");
839 else if (is_Compiler_thread()) st->print("CompilerThread");
840 else if (is_Java_thread()) st->print("JavaThread");
841 else if (is_GC_task_thread()) st->print("GCTaskThread");
842 else if (is_Watcher_thread()) st->print("WatcherThread");
843 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
844 else st->print("Thread");
845
846 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
847 _stack_base - _stack_size, _stack_base);
848
849 if (osthread()) {
850 st->print(" [id=%d]", osthread()->thread_id());
851 }
852 }
853
854 #ifdef ASSERT
855 void Thread::print_owned_locks_on(outputStream* st) const {
856 Monitor *cur = _owned_locks;
857 if (cur == NULL) {
858 st->print(" (no locks) ");
859 } else {
860 st->print_cr(" Locks owned:");
861 while (cur) {
862 cur->print_on(st);
863 cur = cur->next();
864 }
865 }
866 }
867
868 static int ref_use_count = 0;
869
870 bool Thread::owns_locks_but_compiled_lock() const {
871 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
872 if (cur != Compile_lock) return true;
873 }
874 return false;
875 }
876
877
878 #endif
879
880 #ifndef PRODUCT
881
882 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
883 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
884 // no threads which allow_vm_block's are held
885 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
886 // Check if current thread is allowed to block at a safepoint
887 if (!(_allow_safepoint_count == 0)) {
888 fatal("Possible safepoint reached by thread that does not allow it");
889 }
890 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
891 fatal("LEAF method calling lock?");
892 }
893
894 #ifdef ASSERT
895 if (potential_vm_operation && is_Java_thread()
896 && !Universe::is_bootstrapping()) {
897 // Make sure we do not hold any locks that the VM thread also uses.
898 // This could potentially lead to deadlocks
899 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
900 // Threads_lock is special, since the safepoint synchronization will not start before this is
901 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
902 // since it is used to transfer control between JavaThreads and the VMThread
903 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
904 if ((cur->allow_vm_block() &&
905 cur != Threads_lock &&
906 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
907 cur != VMOperationRequest_lock &&
908 cur != VMOperationQueue_lock) ||
909 cur->rank() == Mutex::special) {
910 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
911 }
912 }
913 }
914
915 if (GCALotAtAllSafepoints) {
916 // We could enter a safepoint here and thus have a gc
917 InterfaceSupport::check_gc_alot();
918 }
919 #endif
920 }
921 #endif
922
923 bool Thread::is_in_stack(address adr) const {
924 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
925 address end = os::current_stack_pointer();
926 // Allow non Java threads to call this without stack_base
927 if (_stack_base == NULL) return true;
928 if (stack_base() >= adr && adr >= end) return true;
929
930 return false;
931 }
932
933
934 bool Thread::is_in_usable_stack(address adr) const {
935 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
936 size_t usable_stack_size = _stack_size - stack_guard_size;
937
938 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
939 }
940
941
942 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
943 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
944 // used for compilation in the future. If that change is made, the need for these methods
945 // should be revisited, and they should be removed if possible.
946
947 bool Thread::is_lock_owned(address adr) const {
948 return on_local_stack(adr);
949 }
950
951 bool Thread::set_as_starting_thread() {
952 // NOTE: this must be called inside the main thread.
953 return os::create_main_thread((JavaThread*)this);
954 }
955
956 static void initialize_class(Symbol* class_name, TRAPS) {
957 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
958 InstanceKlass::cast(klass)->initialize(CHECK);
959 }
960
961
962 // Creates the initial ThreadGroup
963 static Handle create_initial_thread_group(TRAPS) {
964 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
965 instanceKlassHandle klass (THREAD, k);
966
967 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
968 {
969 JavaValue result(T_VOID);
970 JavaCalls::call_special(&result,
971 system_instance,
972 klass,
973 vmSymbols::object_initializer_name(),
974 vmSymbols::void_method_signature(),
975 CHECK_NH);
976 }
977 Universe::set_system_thread_group(system_instance());
978
979 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
980 {
981 JavaValue result(T_VOID);
982 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
983 JavaCalls::call_special(&result,
984 main_instance,
985 klass,
986 vmSymbols::object_initializer_name(),
987 vmSymbols::threadgroup_string_void_signature(),
988 system_instance,
989 string,
990 CHECK_NH);
991 }
992 return main_instance;
993 }
994
995 // Creates the initial Thread
996 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
997 TRAPS) {
998 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
999 instanceKlassHandle klass (THREAD, k);
1000 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1001
1002 java_lang_Thread::set_thread(thread_oop(), thread);
1003 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1004 thread->set_threadObj(thread_oop());
1005
1006 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1007
1008 JavaValue result(T_VOID);
1009 JavaCalls::call_special(&result, thread_oop,
1010 klass,
1011 vmSymbols::object_initializer_name(),
1012 vmSymbols::threadgroup_string_void_signature(),
1013 thread_group,
1014 string,
1015 CHECK_NULL);
1016 return thread_oop();
1017 }
1018
1019 static void call_initializeSystemClass(TRAPS) {
1020 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1021 instanceKlassHandle klass (THREAD, k);
1022
1023 JavaValue result(T_VOID);
1024 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1025 vmSymbols::void_method_signature(), CHECK);
1026 }
1027
1028 char java_runtime_name[128] = "";
1029 char java_runtime_version[128] = "";
1030
1031 // extract the JRE name from sun.misc.Version.java_runtime_name
1032 static const char* get_java_runtime_name(TRAPS) {
1033 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1034 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1035 fieldDescriptor fd;
1036 bool found = k != NULL &&
1037 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1038 vmSymbols::string_signature(), &fd);
1039 if (found) {
1040 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1041 if (name_oop == NULL) {
1042 return NULL;
1043 }
1044 const char* name = java_lang_String::as_utf8_string(name_oop,
1045 java_runtime_name,
1046 sizeof(java_runtime_name));
1047 return name;
1048 } else {
1049 return NULL;
1050 }
1051 }
1052
1053 // extract the JRE version from sun.misc.Version.java_runtime_version
1054 static const char* get_java_runtime_version(TRAPS) {
1055 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1056 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1057 fieldDescriptor fd;
1058 bool found = k != NULL &&
1059 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1060 vmSymbols::string_signature(), &fd);
1061 if (found) {
1062 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1063 if (name_oop == NULL) {
1064 return NULL;
1065 }
1066 const char* name = java_lang_String::as_utf8_string(name_oop,
1067 java_runtime_version,
1068 sizeof(java_runtime_version));
1069 return name;
1070 } else {
1071 return NULL;
1072 }
1073 }
1074
1075 // General purpose hook into Java code, run once when the VM is initialized.
1076 // The Java library method itself may be changed independently from the VM.
1077 static void call_postVMInitHook(TRAPS) {
1078 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1079 instanceKlassHandle klass (THREAD, k);
1080 if (klass.not_null()) {
1081 JavaValue result(T_VOID);
1082 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1083 vmSymbols::void_method_signature(),
1084 CHECK);
1085 }
1086 }
1087
1088 static void reset_vm_info_property(TRAPS) {
1089 // the vm info string
1090 ResourceMark rm(THREAD);
1091 const char *vm_info = VM_Version::vm_info_string();
1092
1093 // java.lang.System class
1094 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1095 instanceKlassHandle klass (THREAD, k);
1096
1097 // setProperty arguments
1098 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1099 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1100
1101 // return value
1102 JavaValue r(T_OBJECT);
1103
1104 // public static String setProperty(String key, String value);
1105 JavaCalls::call_static(&r,
1106 klass,
1107 vmSymbols::setProperty_name(),
1108 vmSymbols::string_string_string_signature(),
1109 key_str,
1110 value_str,
1111 CHECK);
1112 }
1113
1114
1115 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name,
1116 bool daemon, TRAPS) {
1117 assert(thread_group.not_null(), "thread group should be specified");
1118 assert(threadObj() == NULL, "should only create Java thread object once");
1119
1120 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1121 instanceKlassHandle klass (THREAD, k);
1122 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1123
1124 java_lang_Thread::set_thread(thread_oop(), this);
1125 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1126 set_threadObj(thread_oop());
1127
1128 JavaValue result(T_VOID);
1129 if (thread_name != NULL) {
1130 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1131 // Thread gets assigned specified name and null target
1132 JavaCalls::call_special(&result,
1133 thread_oop,
1134 klass,
1135 vmSymbols::object_initializer_name(),
1136 vmSymbols::threadgroup_string_void_signature(),
1137 thread_group, // Argument 1
1138 name, // Argument 2
1139 THREAD);
1140 } else {
1141 // Thread gets assigned name "Thread-nnn" and null target
1142 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1143 JavaCalls::call_special(&result,
1144 thread_oop,
1145 klass,
1146 vmSymbols::object_initializer_name(),
1147 vmSymbols::threadgroup_runnable_void_signature(),
1148 thread_group, // Argument 1
1149 Handle(), // Argument 2
1150 THREAD);
1151 }
1152
1153
1154 if (daemon) {
1155 java_lang_Thread::set_daemon(thread_oop());
1156 }
1157
1158 if (HAS_PENDING_EXCEPTION) {
1159 return;
1160 }
1161
1162 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1163 Handle threadObj(this, this->threadObj());
1164
1165 JavaCalls::call_special(&result,
1166 thread_group,
1167 group,
1168 vmSymbols::add_method_name(),
1169 vmSymbols::thread_void_signature(),
1170 threadObj, // Arg 1
1171 THREAD);
1172
1173
1174 }
1175
1176 // NamedThread -- non-JavaThread subclasses with multiple
1177 // uniquely named instances should derive from this.
1178 NamedThread::NamedThread() : Thread() {
1179 _name = NULL;
1180 _processed_thread = NULL;
1181 }
1182
1183 NamedThread::~NamedThread() {
1184 if (_name != NULL) {
1185 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1186 _name = NULL;
1187 }
1188 }
1189
1190 void NamedThread::set_name(const char* format, ...) {
1191 guarantee(_name == NULL, "Only get to set name once.");
1192 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1193 guarantee(_name != NULL, "alloc failure");
1194 va_list ap;
1195 va_start(ap, format);
1196 jio_vsnprintf(_name, max_name_len, format, ap);
1197 va_end(ap);
1198 }
1199
1200 void NamedThread::print_on(outputStream* st) const {
1201 st->print("\"%s\" ", name());
1202 Thread::print_on(st);
1203 st->cr();
1204 }
1205
1206
1207 // ======= WatcherThread ========
1208
1209 // The watcher thread exists to simulate timer interrupts. It should
1210 // be replaced by an abstraction over whatever native support for
1211 // timer interrupts exists on the platform.
1212
1213 WatcherThread* WatcherThread::_watcher_thread = NULL;
1214 bool WatcherThread::_startable = false;
1215 volatile bool WatcherThread::_should_terminate = false;
1216
1217 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1218 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1219 if (os::create_thread(this, os::watcher_thread)) {
1220 _watcher_thread = this;
1221
1222 // Set the watcher thread to the highest OS priority which should not be
1223 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1224 // is created. The only normal thread using this priority is the reference
1225 // handler thread, which runs for very short intervals only.
1226 // If the VMThread's priority is not lower than the WatcherThread profiling
1227 // will be inaccurate.
1228 os::set_priority(this, MaxPriority);
1229 if (!DisableStartThread) {
1230 os::start_thread(this);
1231 }
1232 }
1233 }
1234
1235 int WatcherThread::sleep() const {
1236 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1237
1238 // remaining will be zero if there are no tasks,
1239 // causing the WatcherThread to sleep until a task is
1240 // enrolled
1241 int remaining = PeriodicTask::time_to_wait();
1242 int time_slept = 0;
1243
1244 // we expect this to timeout - we only ever get unparked when
1245 // we should terminate or when a new task has been enrolled
1246 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1247
1248 jlong time_before_loop = os::javaTimeNanos();
1249
1250 for (;;) {
1251 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1252 jlong now = os::javaTimeNanos();
1253
1254 if (remaining == 0) {
1255 // if we didn't have any tasks we could have waited for a long time
1256 // consider the time_slept zero and reset time_before_loop
1257 time_slept = 0;
1258 time_before_loop = now;
1259 } else {
1260 // need to recalculate since we might have new tasks in _tasks
1261 time_slept = (int) ((now - time_before_loop) / 1000000);
1262 }
1263
1264 // Change to task list or spurious wakeup of some kind
1265 if (timedout || _should_terminate) {
1266 break;
1267 }
1268
1269 remaining = PeriodicTask::time_to_wait();
1270 if (remaining == 0) {
1271 // Last task was just disenrolled so loop around and wait until
1272 // another task gets enrolled
1273 continue;
1274 }
1275
1276 remaining -= time_slept;
1277 if (remaining <= 0) {
1278 break;
1279 }
1280 }
1281
1282 return time_slept;
1283 }
1284
1285 void WatcherThread::run() {
1286 assert(this == watcher_thread(), "just checking");
1287
1288 this->record_stack_base_and_size();
1289 this->initialize_thread_local_storage();
1290 this->set_native_thread_name(this->name());
1291 this->set_active_handles(JNIHandleBlock::allocate_block());
1292 while (!_should_terminate) {
1293 assert(watcher_thread() == Thread::current(), "thread consistency check");
1294 assert(watcher_thread() == this, "thread consistency check");
1295
1296 // Calculate how long it'll be until the next PeriodicTask work
1297 // should be done, and sleep that amount of time.
1298 int time_waited = sleep();
1299
1300 if (is_error_reported()) {
1301 // A fatal error has happened, the error handler(VMError::report_and_die)
1302 // should abort JVM after creating an error log file. However in some
1303 // rare cases, the error handler itself might deadlock. Here we try to
1304 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1305 //
1306 // This code is in WatcherThread because WatcherThread wakes up
1307 // periodically so the fatal error handler doesn't need to do anything;
1308 // also because the WatcherThread is less likely to crash than other
1309 // threads.
1310
1311 for (;;) {
1312 if (!ShowMessageBoxOnError
1313 && (OnError == NULL || OnError[0] == '\0')
1314 && Arguments::abort_hook() == NULL) {
1315 os::sleep(this, 2 * 60 * 1000, false);
1316 fdStream err(defaultStream::output_fd());
1317 err.print_raw_cr("# [ timer expired, abort... ]");
1318 // skip atexit/vm_exit/vm_abort hooks
1319 os::die();
1320 }
1321
1322 // Wake up 5 seconds later, the fatal handler may reset OnError or
1323 // ShowMessageBoxOnError when it is ready to abort.
1324 os::sleep(this, 5 * 1000, false);
1325 }
1326 }
1327
1328 PeriodicTask::real_time_tick(time_waited);
1329 }
1330
1331 // Signal that it is terminated
1332 {
1333 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1334 _watcher_thread = NULL;
1335 Terminator_lock->notify();
1336 }
1337
1338 // Thread destructor usually does this..
1339 ThreadLocalStorage::set_thread(NULL);
1340 }
1341
1342 void WatcherThread::start() {
1343 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1344
1345 if (watcher_thread() == NULL && _startable) {
1346 _should_terminate = false;
1347 // Create the single instance of WatcherThread
1348 new WatcherThread();
1349 }
1350 }
1351
1352 void WatcherThread::make_startable() {
1353 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1354 _startable = true;
1355 }
1356
1357 void WatcherThread::stop() {
1358 // Get the PeriodicTask_lock if we can. If we cannot, then the
1359 // WatcherThread is using it and we don't want to block on that lock
1360 // here because that might cause a safepoint deadlock depending on
1361 // what the current WatcherThread tasks are doing.
1362 bool have_lock = PeriodicTask_lock->try_lock();
1363
1364 _should_terminate = true;
1365 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1366
1367 if (have_lock) {
1368 WatcherThread* watcher = watcher_thread();
1369 if (watcher != NULL) {
1370 // If we managed to get the lock, then we should unpark the
1371 // WatcherThread so that it can see we want it to stop.
1372 watcher->unpark();
1373 }
1374
1375 PeriodicTask_lock->unlock();
1376 }
1377
1378 // it is ok to take late safepoints here, if needed
1379 MutexLocker mu(Terminator_lock);
1380
1381 while (watcher_thread() != NULL) {
1382 // This wait should make safepoint checks, wait without a timeout,
1383 // and wait as a suspend-equivalent condition.
1384 //
1385 // Note: If the FlatProfiler is running, then this thread is waiting
1386 // for the WatcherThread to terminate and the WatcherThread, via the
1387 // FlatProfiler task, is waiting for the external suspend request on
1388 // this thread to complete. wait_for_ext_suspend_completion() will
1389 // eventually timeout, but that takes time. Making this wait a
1390 // suspend-equivalent condition solves that timeout problem.
1391 //
1392 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1393 Mutex::_as_suspend_equivalent_flag);
1394 }
1395 }
1396
1397 void WatcherThread::unpark() {
1398 MutexLockerEx ml(PeriodicTask_lock->owned_by_self()
1399 ? NULL
1400 : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1401 PeriodicTask_lock->notify();
1402 }
1403
1404 void WatcherThread::print_on(outputStream* st) const {
1405 st->print("\"%s\" ", name());
1406 Thread::print_on(st);
1407 st->cr();
1408 }
1409
1410 // ======= JavaThread ========
1411
1412 // A JavaThread is a normal Java thread
1413
1414 void JavaThread::initialize() {
1415 // Initialize fields
1416
1417 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1418 set_claimed_par_id(UINT_MAX);
1419
1420 set_saved_exception_pc(NULL);
1421 set_threadObj(NULL);
1422 _anchor.clear();
1423 set_entry_point(NULL);
1424 set_jni_functions(jni_functions());
1425 set_callee_target(NULL);
1426 set_vm_result(NULL);
1427 set_vm_result_2(NULL);
1428 set_vframe_array_head(NULL);
1429 set_vframe_array_last(NULL);
1430 set_deferred_locals(NULL);
1431 set_deopt_mark(NULL);
1432 set_deopt_nmethod(NULL);
1433 clear_must_deopt_id();
1434 set_monitor_chunks(NULL);
1435 set_next(NULL);
1436 set_thread_state(_thread_new);
1437 _terminated = _not_terminated;
1438 _privileged_stack_top = NULL;
1439 _array_for_gc = NULL;
1440 _suspend_equivalent = false;
1441 _in_deopt_handler = 0;
1442 _doing_unsafe_access = false;
1443 _stack_guard_state = stack_guard_unused;
1444 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1445 _exception_pc = 0;
1446 _exception_handler_pc = 0;
1447 _is_method_handle_return = 0;
1448 _jvmti_thread_state= NULL;
1449 _should_post_on_exceptions_flag = JNI_FALSE;
1450 _jvmti_get_loaded_classes_closure = NULL;
1451 _interp_only_mode = 0;
1452 _special_runtime_exit_condition = _no_async_condition;
1453 _pending_async_exception = NULL;
1454 _thread_stat = NULL;
1455 _thread_stat = new ThreadStatistics();
1456 _blocked_on_compilation = false;
1457 _jni_active_critical = 0;
1458 _pending_jni_exception_check_fn = NULL;
1459 _do_not_unlock_if_synchronized = false;
1460 _cached_monitor_info = NULL;
1461 _parker = Parker::Allocate(this);
1462
1463 #ifndef PRODUCT
1464 _jmp_ring_index = 0;
1465 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1466 record_jump(NULL, NULL, NULL, 0);
1467 }
1468 #endif // PRODUCT
1469
1470 set_thread_profiler(NULL);
1471 if (FlatProfiler::is_active()) {
1472 // This is where we would decide to either give each thread it's own profiler
1473 // or use one global one from FlatProfiler,
1474 // or up to some count of the number of profiled threads, etc.
1475 ThreadProfiler* pp = new ThreadProfiler();
1476 pp->engage();
1477 set_thread_profiler(pp);
1478 }
1479
1480 // Setup safepoint state info for this thread
1481 ThreadSafepointState::create(this);
1482
1483 debug_only(_java_call_counter = 0);
1484
1485 // JVMTI PopFrame support
1486 _popframe_condition = popframe_inactive;
1487 _popframe_preserved_args = NULL;
1488 _popframe_preserved_args_size = 0;
1489
1490 pd_initialize();
1491 }
1492
1493 #if INCLUDE_ALL_GCS
1494 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1495 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1496 #endif // INCLUDE_ALL_GCS
1497
1498 JavaThread::JavaThread(bool is_attaching_via_jni) :
1499 Thread()
1500 #if INCLUDE_ALL_GCS
1501 , _satb_mark_queue(&_satb_mark_queue_set),
1502 _dirty_card_queue(&_dirty_card_queue_set)
1503 #endif // INCLUDE_ALL_GCS
1504 {
1505 initialize();
1506 if (is_attaching_via_jni) {
1507 _jni_attach_state = _attaching_via_jni;
1508 } else {
1509 _jni_attach_state = _not_attaching_via_jni;
1510 }
1511 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1512 }
1513
1514 bool JavaThread::reguard_stack(address cur_sp) {
1515 if (_stack_guard_state != stack_guard_yellow_disabled) {
1516 return true; // Stack already guarded or guard pages not needed.
1517 }
1518
1519 if (register_stack_overflow()) {
1520 // For those architectures which have separate register and
1521 // memory stacks, we must check the register stack to see if
1522 // it has overflowed.
1523 return false;
1524 }
1525
1526 // Java code never executes within the yellow zone: the latter is only
1527 // there to provoke an exception during stack banging. If java code
1528 // is executing there, either StackShadowPages should be larger, or
1529 // some exception code in c1, c2 or the interpreter isn't unwinding
1530 // when it should.
1531 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1532
1533 enable_stack_yellow_zone();
1534 return true;
1535 }
1536
1537 bool JavaThread::reguard_stack(void) {
1538 return reguard_stack(os::current_stack_pointer());
1539 }
1540
1541
1542 void JavaThread::block_if_vm_exited() {
1543 if (_terminated == _vm_exited) {
1544 // _vm_exited is set at safepoint, and Threads_lock is never released
1545 // we will block here forever
1546 Threads_lock->lock_without_safepoint_check();
1547 ShouldNotReachHere();
1548 }
1549 }
1550
1551
1552 // Remove this ifdef when C1 is ported to the compiler interface.
1553 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1554
1555 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1556 Thread()
1557 #if INCLUDE_ALL_GCS
1558 , _satb_mark_queue(&_satb_mark_queue_set),
1559 _dirty_card_queue(&_dirty_card_queue_set)
1560 #endif // INCLUDE_ALL_GCS
1561 {
1562 if (TraceThreadEvents) {
1563 tty->print_cr("creating thread %p", this);
1564 }
1565 initialize();
1566 _jni_attach_state = _not_attaching_via_jni;
1567 set_entry_point(entry_point);
1568 // Create the native thread itself.
1569 // %note runtime_23
1570 os::ThreadType thr_type = os::java_thread;
1571 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1572 os::java_thread;
1573 os::create_thread(this, thr_type, stack_sz);
1574 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1575 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1576 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1577 // the exception consists of creating the exception object & initializing it, initialization
1578 // will leave the VM via a JavaCall and then all locks must be unlocked).
1579 //
1580 // The thread is still suspended when we reach here. Thread must be explicit started
1581 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1582 // by calling Threads:add. The reason why this is not done here, is because the thread
1583 // object must be fully initialized (take a look at JVM_Start)
1584 }
1585
1586 JavaThread::~JavaThread() {
1587 if (TraceThreadEvents) {
1588 tty->print_cr("terminate thread %p", this);
1589 }
1590
1591 // JSR166 -- return the parker to the free list
1592 Parker::Release(_parker);
1593 _parker = NULL;
1594
1595 // Free any remaining previous UnrollBlock
1596 vframeArray* old_array = vframe_array_last();
1597
1598 if (old_array != NULL) {
1599 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1600 old_array->set_unroll_block(NULL);
1601 delete old_info;
1602 delete old_array;
1603 }
1604
1605 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1606 if (deferred != NULL) {
1607 // This can only happen if thread is destroyed before deoptimization occurs.
1608 assert(deferred->length() != 0, "empty array!");
1609 do {
1610 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1611 deferred->remove_at(0);
1612 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1613 delete dlv;
1614 } while (deferred->length() != 0);
1615 delete deferred;
1616 }
1617
1618 // All Java related clean up happens in exit
1619 ThreadSafepointState::destroy(this);
1620 if (_thread_profiler != NULL) delete _thread_profiler;
1621 if (_thread_stat != NULL) delete _thread_stat;
1622 }
1623
1624
1625 // The first routine called by a new Java thread
1626 void JavaThread::run() {
1627 // initialize thread-local alloc buffer related fields
1628 this->initialize_tlab();
1629
1630 // used to test validity of stack trace backs
1631 this->record_base_of_stack_pointer();
1632
1633 // Record real stack base and size.
1634 this->record_stack_base_and_size();
1635
1636 // Initialize thread local storage; set before calling MutexLocker
1637 this->initialize_thread_local_storage();
1638
1639 this->create_stack_guard_pages();
1640
1641 this->cache_global_variables();
1642
1643 // Thread is now sufficient initialized to be handled by the safepoint code as being
1644 // in the VM. Change thread state from _thread_new to _thread_in_vm
1645 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1646
1647 assert(JavaThread::current() == this, "sanity check");
1648 assert(!Thread::current()->owns_locks(), "sanity check");
1649
1650 DTRACE_THREAD_PROBE(start, this);
1651
1652 // This operation might block. We call that after all safepoint checks for a new thread has
1653 // been completed.
1654 this->set_active_handles(JNIHandleBlock::allocate_block());
1655
1656 if (JvmtiExport::should_post_thread_life()) {
1657 JvmtiExport::post_thread_start(this);
1658 }
1659
1660 EventThreadStart event;
1661 if (event.should_commit()) {
1662 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1663 event.commit();
1664 }
1665
1666 // We call another function to do the rest so we are sure that the stack addresses used
1667 // from there will be lower than the stack base just computed
1668 thread_main_inner();
1669
1670 // Note, thread is no longer valid at this point!
1671 }
1672
1673
1674 void JavaThread::thread_main_inner() {
1675 assert(JavaThread::current() == this, "sanity check");
1676 assert(this->threadObj() != NULL, "just checking");
1677
1678 // Execute thread entry point unless this thread has a pending exception
1679 // or has been stopped before starting.
1680 // Note: Due to JVM_StopThread we can have pending exceptions already!
1681 if (!this->has_pending_exception() &&
1682 !java_lang_Thread::is_stillborn(this->threadObj())) {
1683 {
1684 ResourceMark rm(this);
1685 this->set_native_thread_name(this->get_thread_name());
1686 }
1687 HandleMark hm(this);
1688 this->entry_point()(this, this);
1689 }
1690
1691 DTRACE_THREAD_PROBE(stop, this);
1692
1693 this->exit(false);
1694 delete this;
1695 }
1696
1697
1698 static void ensure_join(JavaThread* thread) {
1699 // We do not need to grap the Threads_lock, since we are operating on ourself.
1700 Handle threadObj(thread, thread->threadObj());
1701 assert(threadObj.not_null(), "java thread object must exist");
1702 ObjectLocker lock(threadObj, thread);
1703 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1704 thread->clear_pending_exception();
1705 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1706 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1707 // Clear the native thread instance - this makes isAlive return false and allows the join()
1708 // to complete once we've done the notify_all below
1709 java_lang_Thread::set_thread(threadObj(), NULL);
1710 lock.notify_all(thread);
1711 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1712 thread->clear_pending_exception();
1713 }
1714
1715
1716 // For any new cleanup additions, please check to see if they need to be applied to
1717 // cleanup_failed_attach_current_thread as well.
1718 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1719 assert(this == JavaThread::current(), "thread consistency check");
1720
1721 HandleMark hm(this);
1722 Handle uncaught_exception(this, this->pending_exception());
1723 this->clear_pending_exception();
1724 Handle threadObj(this, this->threadObj());
1725 assert(threadObj.not_null(), "Java thread object should be created");
1726
1727 if (get_thread_profiler() != NULL) {
1728 get_thread_profiler()->disengage();
1729 ResourceMark rm;
1730 get_thread_profiler()->print(get_thread_name());
1731 }
1732
1733
1734 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1735 {
1736 EXCEPTION_MARK;
1737
1738 CLEAR_PENDING_EXCEPTION;
1739 }
1740 if (!destroy_vm) {
1741 if (uncaught_exception.not_null()) {
1742 EXCEPTION_MARK;
1743 // Call method Thread.dispatchUncaughtException().
1744 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1745 JavaValue result(T_VOID);
1746 JavaCalls::call_virtual(&result,
1747 threadObj, thread_klass,
1748 vmSymbols::dispatchUncaughtException_name(),
1749 vmSymbols::throwable_void_signature(),
1750 uncaught_exception,
1751 THREAD);
1752 if (HAS_PENDING_EXCEPTION) {
1753 ResourceMark rm(this);
1754 jio_fprintf(defaultStream::error_stream(),
1755 "\nException: %s thrown from the UncaughtExceptionHandler"
1756 " in thread \"%s\"\n",
1757 pending_exception()->klass()->external_name(),
1758 get_thread_name());
1759 CLEAR_PENDING_EXCEPTION;
1760 }
1761 }
1762
1763 // Called before the java thread exit since we want to read info
1764 // from java_lang_Thread object
1765 EventThreadEnd event;
1766 if (event.should_commit()) {
1767 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1768 event.commit();
1769 }
1770
1771 // Call after last event on thread
1772 EVENT_THREAD_EXIT(this);
1773
1774 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1775 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1776 // is deprecated anyhow.
1777 if (!is_Compiler_thread()) {
1778 int count = 3;
1779 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1780 EXCEPTION_MARK;
1781 JavaValue result(T_VOID);
1782 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1783 JavaCalls::call_virtual(&result,
1784 threadObj, thread_klass,
1785 vmSymbols::exit_method_name(),
1786 vmSymbols::void_method_signature(),
1787 THREAD);
1788 CLEAR_PENDING_EXCEPTION;
1789 }
1790 }
1791 // notify JVMTI
1792 if (JvmtiExport::should_post_thread_life()) {
1793 JvmtiExport::post_thread_end(this);
1794 }
1795
1796 // We have notified the agents that we are exiting, before we go on,
1797 // we must check for a pending external suspend request and honor it
1798 // in order to not surprise the thread that made the suspend request.
1799 while (true) {
1800 {
1801 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1802 if (!is_external_suspend()) {
1803 set_terminated(_thread_exiting);
1804 ThreadService::current_thread_exiting(this);
1805 break;
1806 }
1807 // Implied else:
1808 // Things get a little tricky here. We have a pending external
1809 // suspend request, but we are holding the SR_lock so we
1810 // can't just self-suspend. So we temporarily drop the lock
1811 // and then self-suspend.
1812 }
1813
1814 ThreadBlockInVM tbivm(this);
1815 java_suspend_self();
1816
1817 // We're done with this suspend request, but we have to loop around
1818 // and check again. Eventually we will get SR_lock without a pending
1819 // external suspend request and will be able to mark ourselves as
1820 // exiting.
1821 }
1822 // no more external suspends are allowed at this point
1823 } else {
1824 // before_exit() has already posted JVMTI THREAD_END events
1825 }
1826
1827 // Notify waiters on thread object. This has to be done after exit() is called
1828 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1829 // group should have the destroyed bit set before waiters are notified).
1830 ensure_join(this);
1831 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1832
1833 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1834 // held by this thread must be released. A detach operation must only
1835 // get here if there are no Java frames on the stack. Therefore, any
1836 // owned monitors at this point MUST be JNI-acquired monitors which are
1837 // pre-inflated and in the monitor cache.
1838 //
1839 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1840 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1841 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1842 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1843 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1844 }
1845
1846 // These things needs to be done while we are still a Java Thread. Make sure that thread
1847 // is in a consistent state, in case GC happens
1848 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1849
1850 if (active_handles() != NULL) {
1851 JNIHandleBlock* block = active_handles();
1852 set_active_handles(NULL);
1853 JNIHandleBlock::release_block(block);
1854 }
1855
1856 if (free_handle_block() != NULL) {
1857 JNIHandleBlock* block = free_handle_block();
1858 set_free_handle_block(NULL);
1859 JNIHandleBlock::release_block(block);
1860 }
1861
1862 // These have to be removed while this is still a valid thread.
1863 remove_stack_guard_pages();
1864
1865 if (UseTLAB) {
1866 tlab().make_parsable(true); // retire TLAB
1867 }
1868
1869 if (JvmtiEnv::environments_might_exist()) {
1870 JvmtiExport::cleanup_thread(this);
1871 }
1872
1873 // We must flush any deferred card marks before removing a thread from
1874 // the list of active threads.
1875 Universe::heap()->flush_deferred_store_barrier(this);
1876 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1877
1878 #if INCLUDE_ALL_GCS
1879 // We must flush the G1-related buffers before removing a thread
1880 // from the list of active threads. We must do this after any deferred
1881 // card marks have been flushed (above) so that any entries that are
1882 // added to the thread's dirty card queue as a result are not lost.
1883 if (UseG1GC) {
1884 flush_barrier_queues();
1885 }
1886 #endif // INCLUDE_ALL_GCS
1887
1888 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1889 Threads::remove(this);
1890 }
1891
1892 #if INCLUDE_ALL_GCS
1893 // Flush G1-related queues.
1894 void JavaThread::flush_barrier_queues() {
1895 satb_mark_queue().flush();
1896 dirty_card_queue().flush();
1897 }
1898
1899 void JavaThread::initialize_queues() {
1900 assert(!SafepointSynchronize::is_at_safepoint(),
1901 "we should not be at a safepoint");
1902
1903 ObjPtrQueue& satb_queue = satb_mark_queue();
1904 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1905 // The SATB queue should have been constructed with its active
1906 // field set to false.
1907 assert(!satb_queue.is_active(), "SATB queue should not be active");
1908 assert(satb_queue.is_empty(), "SATB queue should be empty");
1909 // If we are creating the thread during a marking cycle, we should
1910 // set the active field of the SATB queue to true.
1911 if (satb_queue_set.is_active()) {
1912 satb_queue.set_active(true);
1913 }
1914
1915 DirtyCardQueue& dirty_queue = dirty_card_queue();
1916 // The dirty card queue should have been constructed with its
1917 // active field set to true.
1918 assert(dirty_queue.is_active(), "dirty card queue should be active");
1919 }
1920 #endif // INCLUDE_ALL_GCS
1921
1922 void JavaThread::cleanup_failed_attach_current_thread() {
1923 if (get_thread_profiler() != NULL) {
1924 get_thread_profiler()->disengage();
1925 ResourceMark rm;
1926 get_thread_profiler()->print(get_thread_name());
1927 }
1928
1929 if (active_handles() != NULL) {
1930 JNIHandleBlock* block = active_handles();
1931 set_active_handles(NULL);
1932 JNIHandleBlock::release_block(block);
1933 }
1934
1935 if (free_handle_block() != NULL) {
1936 JNIHandleBlock* block = free_handle_block();
1937 set_free_handle_block(NULL);
1938 JNIHandleBlock::release_block(block);
1939 }
1940
1941 // These have to be removed while this is still a valid thread.
1942 remove_stack_guard_pages();
1943
1944 if (UseTLAB) {
1945 tlab().make_parsable(true); // retire TLAB, if any
1946 }
1947
1948 #if INCLUDE_ALL_GCS
1949 if (UseG1GC) {
1950 flush_barrier_queues();
1951 }
1952 #endif // INCLUDE_ALL_GCS
1953
1954 Threads::remove(this);
1955 delete this;
1956 }
1957
1958
1959
1960
1961 JavaThread* JavaThread::active() {
1962 Thread* thread = ThreadLocalStorage::thread();
1963 assert(thread != NULL, "just checking");
1964 if (thread->is_Java_thread()) {
1965 return (JavaThread*) thread;
1966 } else {
1967 assert(thread->is_VM_thread(), "this must be a vm thread");
1968 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1969 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1970 assert(ret->is_Java_thread(), "must be a Java thread");
1971 return ret;
1972 }
1973 }
1974
1975 bool JavaThread::is_lock_owned(address adr) const {
1976 if (Thread::is_lock_owned(adr)) return true;
1977
1978 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1979 if (chunk->contains(adr)) return true;
1980 }
1981
1982 return false;
1983 }
1984
1985
1986 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1987 chunk->set_next(monitor_chunks());
1988 set_monitor_chunks(chunk);
1989 }
1990
1991 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1992 guarantee(monitor_chunks() != NULL, "must be non empty");
1993 if (monitor_chunks() == chunk) {
1994 set_monitor_chunks(chunk->next());
1995 } else {
1996 MonitorChunk* prev = monitor_chunks();
1997 while (prev->next() != chunk) prev = prev->next();
1998 prev->set_next(chunk->next());
1999 }
2000 }
2001
2002 // JVM support.
2003
2004 // Note: this function shouldn't block if it's called in
2005 // _thread_in_native_trans state (such as from
2006 // check_special_condition_for_native_trans()).
2007 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2008
2009 if (has_last_Java_frame() && has_async_condition()) {
2010 // If we are at a polling page safepoint (not a poll return)
2011 // then we must defer async exception because live registers
2012 // will be clobbered by the exception path. Poll return is
2013 // ok because the call we a returning from already collides
2014 // with exception handling registers and so there is no issue.
2015 // (The exception handling path kills call result registers but
2016 // this is ok since the exception kills the result anyway).
2017
2018 if (is_at_poll_safepoint()) {
2019 // if the code we are returning to has deoptimized we must defer
2020 // the exception otherwise live registers get clobbered on the
2021 // exception path before deoptimization is able to retrieve them.
2022 //
2023 RegisterMap map(this, false);
2024 frame caller_fr = last_frame().sender(&map);
2025 assert(caller_fr.is_compiled_frame(), "what?");
2026 if (caller_fr.is_deoptimized_frame()) {
2027 if (TraceExceptions) {
2028 ResourceMark rm;
2029 tty->print_cr("deferred async exception at compiled safepoint");
2030 }
2031 return;
2032 }
2033 }
2034 }
2035
2036 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2037 if (condition == _no_async_condition) {
2038 // Conditions have changed since has_special_runtime_exit_condition()
2039 // was called:
2040 // - if we were here only because of an external suspend request,
2041 // then that was taken care of above (or cancelled) so we are done
2042 // - if we were here because of another async request, then it has
2043 // been cleared between the has_special_runtime_exit_condition()
2044 // and now so again we are done
2045 return;
2046 }
2047
2048 // Check for pending async. exception
2049 if (_pending_async_exception != NULL) {
2050 // Only overwrite an already pending exception, if it is not a threadDeath.
2051 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2052
2053 // We cannot call Exceptions::_throw(...) here because we cannot block
2054 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2055
2056 if (TraceExceptions) {
2057 ResourceMark rm;
2058 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2059 if (has_last_Java_frame()) {
2060 frame f = last_frame();
2061 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2062 }
2063 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2064 }
2065 _pending_async_exception = NULL;
2066 clear_has_async_exception();
2067 }
2068 }
2069
2070 if (check_unsafe_error &&
2071 condition == _async_unsafe_access_error && !has_pending_exception()) {
2072 condition = _no_async_condition; // done
2073 switch (thread_state()) {
2074 case _thread_in_vm: {
2075 JavaThread* THREAD = this;
2076 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2077 }
2078 case _thread_in_native: {
2079 ThreadInVMfromNative tiv(this);
2080 JavaThread* THREAD = this;
2081 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2082 }
2083 case _thread_in_Java: {
2084 ThreadInVMfromJava tiv(this);
2085 JavaThread* THREAD = this;
2086 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2087 }
2088 default:
2089 ShouldNotReachHere();
2090 }
2091 }
2092
2093 assert(condition == _no_async_condition || has_pending_exception() ||
2094 (!check_unsafe_error && condition == _async_unsafe_access_error),
2095 "must have handled the async condition, if no exception");
2096 }
2097
2098 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2099 //
2100 // Check for pending external suspend. Internal suspend requests do
2101 // not use handle_special_runtime_exit_condition().
2102 // If JNIEnv proxies are allowed, don't self-suspend if the target
2103 // thread is not the current thread. In older versions of jdbx, jdbx
2104 // threads could call into the VM with another thread's JNIEnv so we
2105 // can be here operating on behalf of a suspended thread (4432884).
2106 bool do_self_suspend = is_external_suspend_with_lock();
2107 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2108 //
2109 // Because thread is external suspended the safepoint code will count
2110 // thread as at a safepoint. This can be odd because we can be here
2111 // as _thread_in_Java which would normally transition to _thread_blocked
2112 // at a safepoint. We would like to mark the thread as _thread_blocked
2113 // before calling java_suspend_self like all other callers of it but
2114 // we must then observe proper safepoint protocol. (We can't leave
2115 // _thread_blocked with a safepoint in progress). However we can be
2116 // here as _thread_in_native_trans so we can't use a normal transition
2117 // constructor/destructor pair because they assert on that type of
2118 // transition. We could do something like:
2119 //
2120 // JavaThreadState state = thread_state();
2121 // set_thread_state(_thread_in_vm);
2122 // {
2123 // ThreadBlockInVM tbivm(this);
2124 // java_suspend_self()
2125 // }
2126 // set_thread_state(_thread_in_vm_trans);
2127 // if (safepoint) block;
2128 // set_thread_state(state);
2129 //
2130 // but that is pretty messy. Instead we just go with the way the
2131 // code has worked before and note that this is the only path to
2132 // java_suspend_self that doesn't put the thread in _thread_blocked
2133 // mode.
2134
2135 frame_anchor()->make_walkable(this);
2136 java_suspend_self();
2137
2138 // We might be here for reasons in addition to the self-suspend request
2139 // so check for other async requests.
2140 }
2141
2142 if (check_asyncs) {
2143 check_and_handle_async_exceptions();
2144 }
2145 }
2146
2147 void JavaThread::send_thread_stop(oop java_throwable) {
2148 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2149 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2150 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2151
2152 // Do not throw asynchronous exceptions against the compiler thread
2153 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2154 if (is_Compiler_thread()) return;
2155
2156 {
2157 // Actually throw the Throwable against the target Thread - however
2158 // only if there is no thread death exception installed already.
2159 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2160 // If the topmost frame is a runtime stub, then we are calling into
2161 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2162 // must deoptimize the caller before continuing, as the compiled exception handler table
2163 // may not be valid
2164 if (has_last_Java_frame()) {
2165 frame f = last_frame();
2166 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2167 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2168 RegisterMap reg_map(this, UseBiasedLocking);
2169 frame compiled_frame = f.sender(®_map);
2170 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2171 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2172 }
2173 }
2174 }
2175
2176 // Set async. pending exception in thread.
2177 set_pending_async_exception(java_throwable);
2178
2179 if (TraceExceptions) {
2180 ResourceMark rm;
2181 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2182 }
2183 // for AbortVMOnException flag
2184 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2185 }
2186 }
2187
2188
2189 // Interrupt thread so it will wake up from a potential wait()
2190 Thread::interrupt(this);
2191 }
2192
2193 // External suspension mechanism.
2194 //
2195 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2196 // to any VM_locks and it is at a transition
2197 // Self-suspension will happen on the transition out of the vm.
2198 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2199 //
2200 // Guarantees on return:
2201 // + Target thread will not execute any new bytecode (that's why we need to
2202 // force a safepoint)
2203 // + Target thread will not enter any new monitors
2204 //
2205 void JavaThread::java_suspend() {
2206 { MutexLocker mu(Threads_lock);
2207 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2208 return;
2209 }
2210 }
2211
2212 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2213 if (!is_external_suspend()) {
2214 // a racing resume has cancelled us; bail out now
2215 return;
2216 }
2217
2218 // suspend is done
2219 uint32_t debug_bits = 0;
2220 // Warning: is_ext_suspend_completed() may temporarily drop the
2221 // SR_lock to allow the thread to reach a stable thread state if
2222 // it is currently in a transient thread state.
2223 if (is_ext_suspend_completed(false /* !called_by_wait */,
2224 SuspendRetryDelay, &debug_bits)) {
2225 return;
2226 }
2227 }
2228
2229 VM_ForceSafepoint vm_suspend;
2230 VMThread::execute(&vm_suspend);
2231 }
2232
2233 // Part II of external suspension.
2234 // A JavaThread self suspends when it detects a pending external suspend
2235 // request. This is usually on transitions. It is also done in places
2236 // where continuing to the next transition would surprise the caller,
2237 // e.g., monitor entry.
2238 //
2239 // Returns the number of times that the thread self-suspended.
2240 //
2241 // Note: DO NOT call java_suspend_self() when you just want to block current
2242 // thread. java_suspend_self() is the second stage of cooperative
2243 // suspension for external suspend requests and should only be used
2244 // to complete an external suspend request.
2245 //
2246 int JavaThread::java_suspend_self() {
2247 int ret = 0;
2248
2249 // we are in the process of exiting so don't suspend
2250 if (is_exiting()) {
2251 clear_external_suspend();
2252 return ret;
2253 }
2254
2255 assert(_anchor.walkable() ||
2256 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2257 "must have walkable stack");
2258
2259 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2260
2261 assert(!this->is_ext_suspended(),
2262 "a thread trying to self-suspend should not already be suspended");
2263
2264 if (this->is_suspend_equivalent()) {
2265 // If we are self-suspending as a result of the lifting of a
2266 // suspend equivalent condition, then the suspend_equivalent
2267 // flag is not cleared until we set the ext_suspended flag so
2268 // that wait_for_ext_suspend_completion() returns consistent
2269 // results.
2270 this->clear_suspend_equivalent();
2271 }
2272
2273 // A racing resume may have cancelled us before we grabbed SR_lock
2274 // above. Or another external suspend request could be waiting for us
2275 // by the time we return from SR_lock()->wait(). The thread
2276 // that requested the suspension may already be trying to walk our
2277 // stack and if we return now, we can change the stack out from under
2278 // it. This would be a "bad thing (TM)" and cause the stack walker
2279 // to crash. We stay self-suspended until there are no more pending
2280 // external suspend requests.
2281 while (is_external_suspend()) {
2282 ret++;
2283 this->set_ext_suspended();
2284
2285 // _ext_suspended flag is cleared by java_resume()
2286 while (is_ext_suspended()) {
2287 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2288 }
2289 }
2290
2291 return ret;
2292 }
2293
2294 #ifdef ASSERT
2295 // verify the JavaThread has not yet been published in the Threads::list, and
2296 // hence doesn't need protection from concurrent access at this stage
2297 void JavaThread::verify_not_published() {
2298 if (!Threads_lock->owned_by_self()) {
2299 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2300 assert(!Threads::includes(this),
2301 "java thread shouldn't have been published yet!");
2302 } else {
2303 assert(!Threads::includes(this),
2304 "java thread shouldn't have been published yet!");
2305 }
2306 }
2307 #endif
2308
2309 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2310 // progress or when _suspend_flags is non-zero.
2311 // Current thread needs to self-suspend if there is a suspend request and/or
2312 // block if a safepoint is in progress.
2313 // Async exception ISN'T checked.
2314 // Note only the ThreadInVMfromNative transition can call this function
2315 // directly and when thread state is _thread_in_native_trans
2316 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2317 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2318
2319 JavaThread *curJT = JavaThread::current();
2320 bool do_self_suspend = thread->is_external_suspend();
2321
2322 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2323
2324 // If JNIEnv proxies are allowed, don't self-suspend if the target
2325 // thread is not the current thread. In older versions of jdbx, jdbx
2326 // threads could call into the VM with another thread's JNIEnv so we
2327 // can be here operating on behalf of a suspended thread (4432884).
2328 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2329 JavaThreadState state = thread->thread_state();
2330
2331 // We mark this thread_blocked state as a suspend-equivalent so
2332 // that a caller to is_ext_suspend_completed() won't be confused.
2333 // The suspend-equivalent state is cleared by java_suspend_self().
2334 thread->set_suspend_equivalent();
2335
2336 // If the safepoint code sees the _thread_in_native_trans state, it will
2337 // wait until the thread changes to other thread state. There is no
2338 // guarantee on how soon we can obtain the SR_lock and complete the
2339 // self-suspend request. It would be a bad idea to let safepoint wait for
2340 // too long. Temporarily change the state to _thread_blocked to
2341 // let the VM thread know that this thread is ready for GC. The problem
2342 // of changing thread state is that safepoint could happen just after
2343 // java_suspend_self() returns after being resumed, and VM thread will
2344 // see the _thread_blocked state. We must check for safepoint
2345 // after restoring the state and make sure we won't leave while a safepoint
2346 // is in progress.
2347 thread->set_thread_state(_thread_blocked);
2348 thread->java_suspend_self();
2349 thread->set_thread_state(state);
2350 // Make sure new state is seen by VM thread
2351 if (os::is_MP()) {
2352 if (UseMembar) {
2353 // Force a fence between the write above and read below
2354 OrderAccess::fence();
2355 } else {
2356 // Must use this rather than serialization page in particular on Windows
2357 InterfaceSupport::serialize_memory(thread);
2358 }
2359 }
2360 }
2361
2362 if (SafepointSynchronize::do_call_back()) {
2363 // If we are safepointing, then block the caller which may not be
2364 // the same as the target thread (see above).
2365 SafepointSynchronize::block(curJT);
2366 }
2367
2368 if (thread->is_deopt_suspend()) {
2369 thread->clear_deopt_suspend();
2370 RegisterMap map(thread, false);
2371 frame f = thread->last_frame();
2372 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2373 f = f.sender(&map);
2374 }
2375 if (f.id() == thread->must_deopt_id()) {
2376 thread->clear_must_deopt_id();
2377 f.deoptimize(thread);
2378 } else {
2379 fatal("missed deoptimization!");
2380 }
2381 }
2382 }
2383
2384 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2385 // progress or when _suspend_flags is non-zero.
2386 // Current thread needs to self-suspend if there is a suspend request and/or
2387 // block if a safepoint is in progress.
2388 // Also check for pending async exception (not including unsafe access error).
2389 // Note only the native==>VM/Java barriers can call this function and when
2390 // thread state is _thread_in_native_trans.
2391 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2392 check_safepoint_and_suspend_for_native_trans(thread);
2393
2394 if (thread->has_async_exception()) {
2395 // We are in _thread_in_native_trans state, don't handle unsafe
2396 // access error since that may block.
2397 thread->check_and_handle_async_exceptions(false);
2398 }
2399 }
2400
2401 // This is a variant of the normal
2402 // check_special_condition_for_native_trans with slightly different
2403 // semantics for use by critical native wrappers. It does all the
2404 // normal checks but also performs the transition back into
2405 // thread_in_Java state. This is required so that critical natives
2406 // can potentially block and perform a GC if they are the last thread
2407 // exiting the GC_locker.
2408 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2409 check_special_condition_for_native_trans(thread);
2410
2411 // Finish the transition
2412 thread->set_thread_state(_thread_in_Java);
2413
2414 if (thread->do_critical_native_unlock()) {
2415 ThreadInVMfromJavaNoAsyncException tiv(thread);
2416 GC_locker::unlock_critical(thread);
2417 thread->clear_critical_native_unlock();
2418 }
2419 }
2420
2421 // We need to guarantee the Threads_lock here, since resumes are not
2422 // allowed during safepoint synchronization
2423 // Can only resume from an external suspension
2424 void JavaThread::java_resume() {
2425 assert_locked_or_safepoint(Threads_lock);
2426
2427 // Sanity check: thread is gone, has started exiting or the thread
2428 // was not externally suspended.
2429 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2430 return;
2431 }
2432
2433 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2434
2435 clear_external_suspend();
2436
2437 if (is_ext_suspended()) {
2438 clear_ext_suspended();
2439 SR_lock()->notify_all();
2440 }
2441 }
2442
2443 void JavaThread::create_stack_guard_pages() {
2444 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2445 address low_addr = stack_base() - stack_size();
2446 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2447
2448 int allocate = os::allocate_stack_guard_pages();
2449 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2450
2451 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2452 warning("Attempt to allocate stack guard pages failed.");
2453 return;
2454 }
2455
2456 if (os::guard_memory((char *) low_addr, len)) {
2457 _stack_guard_state = stack_guard_enabled;
2458 } else {
2459 warning("Attempt to protect stack guard pages failed.");
2460 if (os::uncommit_memory((char *) low_addr, len)) {
2461 warning("Attempt to deallocate stack guard pages failed.");
2462 }
2463 }
2464 }
2465
2466 void JavaThread::remove_stack_guard_pages() {
2467 assert(Thread::current() == this, "from different thread");
2468 if (_stack_guard_state == stack_guard_unused) return;
2469 address low_addr = stack_base() - stack_size();
2470 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2471
2472 if (os::allocate_stack_guard_pages()) {
2473 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2474 _stack_guard_state = stack_guard_unused;
2475 } else {
2476 warning("Attempt to deallocate stack guard pages failed.");
2477 }
2478 } else {
2479 if (_stack_guard_state == stack_guard_unused) return;
2480 if (os::unguard_memory((char *) low_addr, len)) {
2481 _stack_guard_state = stack_guard_unused;
2482 } else {
2483 warning("Attempt to unprotect stack guard pages failed.");
2484 }
2485 }
2486 }
2487
2488 void JavaThread::enable_stack_yellow_zone() {
2489 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2490 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2491
2492 // The base notation is from the stacks point of view, growing downward.
2493 // We need to adjust it to work correctly with guard_memory()
2494 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2495
2496 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2497 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2498
2499 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2500 _stack_guard_state = stack_guard_enabled;
2501 } else {
2502 warning("Attempt to guard stack yellow zone failed.");
2503 }
2504 enable_register_stack_guard();
2505 }
2506
2507 void JavaThread::disable_stack_yellow_zone() {
2508 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2509 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2510
2511 // Simply return if called for a thread that does not use guard pages.
2512 if (_stack_guard_state == stack_guard_unused) return;
2513
2514 // The base notation is from the stacks point of view, growing downward.
2515 // We need to adjust it to work correctly with guard_memory()
2516 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2517
2518 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2519 _stack_guard_state = stack_guard_yellow_disabled;
2520 } else {
2521 warning("Attempt to unguard stack yellow zone failed.");
2522 }
2523 disable_register_stack_guard();
2524 }
2525
2526 void JavaThread::enable_stack_red_zone() {
2527 // The base notation is from the stacks point of view, growing downward.
2528 // We need to adjust it to work correctly with guard_memory()
2529 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2530 address base = stack_red_zone_base() - stack_red_zone_size();
2531
2532 guarantee(base < stack_base(), "Error calculating stack red zone");
2533 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2534
2535 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2536 warning("Attempt to guard stack red zone failed.");
2537 }
2538 }
2539
2540 void JavaThread::disable_stack_red_zone() {
2541 // The base notation is from the stacks point of view, growing downward.
2542 // We need to adjust it to work correctly with guard_memory()
2543 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2544 address base = stack_red_zone_base() - stack_red_zone_size();
2545 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2546 warning("Attempt to unguard stack red zone failed.");
2547 }
2548 }
2549
2550 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2551 // ignore is there is no stack
2552 if (!has_last_Java_frame()) return;
2553 // traverse the stack frames. Starts from top frame.
2554 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2555 frame* fr = fst.current();
2556 f(fr, fst.register_map());
2557 }
2558 }
2559
2560
2561 #ifndef PRODUCT
2562 // Deoptimization
2563 // Function for testing deoptimization
2564 void JavaThread::deoptimize() {
2565 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2566 StackFrameStream fst(this, UseBiasedLocking);
2567 bool deopt = false; // Dump stack only if a deopt actually happens.
2568 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2569 // Iterate over all frames in the thread and deoptimize
2570 for (; !fst.is_done(); fst.next()) {
2571 if (fst.current()->can_be_deoptimized()) {
2572
2573 if (only_at) {
2574 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2575 // consists of comma or carriage return separated numbers so
2576 // search for the current bci in that string.
2577 address pc = fst.current()->pc();
2578 nmethod* nm = (nmethod*) fst.current()->cb();
2579 ScopeDesc* sd = nm->scope_desc_at(pc);
2580 char buffer[8];
2581 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2582 size_t len = strlen(buffer);
2583 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2584 while (found != NULL) {
2585 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2586 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2587 // Check that the bci found is bracketed by terminators.
2588 break;
2589 }
2590 found = strstr(found + 1, buffer);
2591 }
2592 if (!found) {
2593 continue;
2594 }
2595 }
2596
2597 if (DebugDeoptimization && !deopt) {
2598 deopt = true; // One-time only print before deopt
2599 tty->print_cr("[BEFORE Deoptimization]");
2600 trace_frames();
2601 trace_stack();
2602 }
2603 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2604 }
2605 }
2606
2607 if (DebugDeoptimization && deopt) {
2608 tty->print_cr("[AFTER Deoptimization]");
2609 trace_frames();
2610 }
2611 }
2612
2613
2614 // Make zombies
2615 void JavaThread::make_zombies() {
2616 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2617 if (fst.current()->can_be_deoptimized()) {
2618 // it is a Java nmethod
2619 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2620 nm->make_not_entrant();
2621 }
2622 }
2623 }
2624 #endif // PRODUCT
2625
2626
2627 void JavaThread::deoptimized_wrt_marked_nmethods() {
2628 if (!has_last_Java_frame()) return;
2629 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2630 StackFrameStream fst(this, UseBiasedLocking);
2631 for (; !fst.is_done(); fst.next()) {
2632 if (fst.current()->should_be_deoptimized()) {
2633 if (LogCompilation && xtty != NULL) {
2634 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2635 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2636 this->name(), nm != NULL ? nm->compile_id() : -1);
2637 }
2638
2639 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2640 }
2641 }
2642 }
2643
2644
2645 // If the caller is a NamedThread, then remember, in the current scope,
2646 // the given JavaThread in its _processed_thread field.
2647 class RememberProcessedThread: public StackObj {
2648 NamedThread* _cur_thr;
2649 public:
2650 RememberProcessedThread(JavaThread* jthr) {
2651 Thread* thread = Thread::current();
2652 if (thread->is_Named_thread()) {
2653 _cur_thr = (NamedThread *)thread;
2654 _cur_thr->set_processed_thread(jthr);
2655 } else {
2656 _cur_thr = NULL;
2657 }
2658 }
2659
2660 ~RememberProcessedThread() {
2661 if (_cur_thr) {
2662 _cur_thr->set_processed_thread(NULL);
2663 }
2664 }
2665 };
2666
2667 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2668 // Verify that the deferred card marks have been flushed.
2669 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2670
2671 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2672 // since there may be more than one thread using each ThreadProfiler.
2673
2674 // Traverse the GCHandles
2675 Thread::oops_do(f, cld_f, cf);
2676
2677 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2678 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2679
2680 if (has_last_Java_frame()) {
2681 // Record JavaThread to GC thread
2682 RememberProcessedThread rpt(this);
2683
2684 // Traverse the privileged stack
2685 if (_privileged_stack_top != NULL) {
2686 _privileged_stack_top->oops_do(f);
2687 }
2688
2689 // traverse the registered growable array
2690 if (_array_for_gc != NULL) {
2691 for (int index = 0; index < _array_for_gc->length(); index++) {
2692 f->do_oop(_array_for_gc->adr_at(index));
2693 }
2694 }
2695
2696 // Traverse the monitor chunks
2697 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2698 chunk->oops_do(f);
2699 }
2700
2701 // Traverse the execution stack
2702 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2703 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2704 }
2705 }
2706
2707 // callee_target is never live across a gc point so NULL it here should
2708 // it still contain a methdOop.
2709
2710 set_callee_target(NULL);
2711
2712 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2713 // If we have deferred set_locals there might be oops waiting to be
2714 // written
2715 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2716 if (list != NULL) {
2717 for (int i = 0; i < list->length(); i++) {
2718 list->at(i)->oops_do(f);
2719 }
2720 }
2721
2722 // Traverse instance variables at the end since the GC may be moving things
2723 // around using this function
2724 f->do_oop((oop*) &_threadObj);
2725 f->do_oop((oop*) &_vm_result);
2726 f->do_oop((oop*) &_exception_oop);
2727 f->do_oop((oop*) &_pending_async_exception);
2728
2729 if (jvmti_thread_state() != NULL) {
2730 jvmti_thread_state()->oops_do(f);
2731 }
2732 }
2733
2734 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2735 Thread::nmethods_do(cf); // (super method is a no-op)
2736
2737 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2738 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2739
2740 if (has_last_Java_frame()) {
2741 // Traverse the execution stack
2742 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2743 fst.current()->nmethods_do(cf);
2744 }
2745 }
2746 }
2747
2748 void JavaThread::metadata_do(void f(Metadata*)) {
2749 Thread::metadata_do(f);
2750 if (has_last_Java_frame()) {
2751 // Traverse the execution stack to call f() on the methods in the stack
2752 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2753 fst.current()->metadata_do(f);
2754 }
2755 } else if (is_Compiler_thread()) {
2756 // need to walk ciMetadata in current compile tasks to keep alive.
2757 CompilerThread* ct = (CompilerThread*)this;
2758 if (ct->env() != NULL) {
2759 ct->env()->metadata_do(f);
2760 }
2761 }
2762 }
2763
2764 // Printing
2765 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2766 switch (_thread_state) {
2767 case _thread_uninitialized: return "_thread_uninitialized";
2768 case _thread_new: return "_thread_new";
2769 case _thread_new_trans: return "_thread_new_trans";
2770 case _thread_in_native: return "_thread_in_native";
2771 case _thread_in_native_trans: return "_thread_in_native_trans";
2772 case _thread_in_vm: return "_thread_in_vm";
2773 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2774 case _thread_in_Java: return "_thread_in_Java";
2775 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2776 case _thread_blocked: return "_thread_blocked";
2777 case _thread_blocked_trans: return "_thread_blocked_trans";
2778 default: return "unknown thread state";
2779 }
2780 }
2781
2782 #ifndef PRODUCT
2783 void JavaThread::print_thread_state_on(outputStream *st) const {
2784 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2785 };
2786 void JavaThread::print_thread_state() const {
2787 print_thread_state_on(tty);
2788 }
2789 #endif // PRODUCT
2790
2791 // Called by Threads::print() for VM_PrintThreads operation
2792 void JavaThread::print_on(outputStream *st) const {
2793 st->print("\"%s\" ", get_thread_name());
2794 oop thread_oop = threadObj();
2795 if (thread_oop != NULL) {
2796 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2797 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2798 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2799 }
2800 Thread::print_on(st);
2801 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2802 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2803 if (thread_oop != NULL) {
2804 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2805 }
2806 #ifndef PRODUCT
2807 print_thread_state_on(st);
2808 _safepoint_state->print_on(st);
2809 #endif // PRODUCT
2810 }
2811
2812 // Called by fatal error handler. The difference between this and
2813 // JavaThread::print() is that we can't grab lock or allocate memory.
2814 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2815 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2816 oop thread_obj = threadObj();
2817 if (thread_obj != NULL) {
2818 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2819 }
2820 st->print(" [");
2821 st->print("%s", _get_thread_state_name(_thread_state));
2822 if (osthread()) {
2823 st->print(", id=%d", osthread()->thread_id());
2824 }
2825 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2826 _stack_base - _stack_size, _stack_base);
2827 st->print("]");
2828 return;
2829 }
2830
2831 // Verification
2832
2833 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2834
2835 void JavaThread::verify() {
2836 // Verify oops in the thread.
2837 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2838
2839 // Verify the stack frames.
2840 frames_do(frame_verify);
2841 }
2842
2843 // CR 6300358 (sub-CR 2137150)
2844 // Most callers of this method assume that it can't return NULL but a
2845 // thread may not have a name whilst it is in the process of attaching to
2846 // the VM - see CR 6412693, and there are places where a JavaThread can be
2847 // seen prior to having it's threadObj set (eg JNI attaching threads and
2848 // if vm exit occurs during initialization). These cases can all be accounted
2849 // for such that this method never returns NULL.
2850 const char* JavaThread::get_thread_name() const {
2851 #ifdef ASSERT
2852 // early safepoints can hit while current thread does not yet have TLS
2853 if (!SafepointSynchronize::is_at_safepoint()) {
2854 Thread *cur = Thread::current();
2855 if (!(cur->is_Java_thread() && cur == this)) {
2856 // Current JavaThreads are allowed to get their own name without
2857 // the Threads_lock.
2858 assert_locked_or_safepoint(Threads_lock);
2859 }
2860 }
2861 #endif // ASSERT
2862 return get_thread_name_string();
2863 }
2864
2865 // Returns a non-NULL representation of this thread's name, or a suitable
2866 // descriptive string if there is no set name
2867 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2868 const char* name_str;
2869 oop thread_obj = threadObj();
2870 if (thread_obj != NULL) {
2871 typeArrayOop name = java_lang_Thread::name(thread_obj);
2872 if (name != NULL) {
2873 if (buf == NULL) {
2874 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR),
2875 name->length());
2876 } else {
2877 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR),
2878 name->length(), buf, buflen);
2879 }
2880 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2881 name_str = "<no-name - thread is attaching>";
2882 } else {
2883 name_str = Thread::name();
2884 }
2885 } else {
2886 name_str = Thread::name();
2887 }
2888 assert(name_str != NULL, "unexpected NULL thread name");
2889 return name_str;
2890 }
2891
2892
2893 const char* JavaThread::get_threadgroup_name() const {
2894 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2895 oop thread_obj = threadObj();
2896 if (thread_obj != NULL) {
2897 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2898 if (thread_group != NULL) {
2899 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2900 // ThreadGroup.name can be null
2901 if (name != NULL) {
2902 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2903 return str;
2904 }
2905 }
2906 }
2907 return NULL;
2908 }
2909
2910 const char* JavaThread::get_parent_name() const {
2911 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2912 oop thread_obj = threadObj();
2913 if (thread_obj != NULL) {
2914 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2915 if (thread_group != NULL) {
2916 oop parent = java_lang_ThreadGroup::parent(thread_group);
2917 if (parent != NULL) {
2918 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2919 // ThreadGroup.name can be null
2920 if (name != NULL) {
2921 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2922 return str;
2923 }
2924 }
2925 }
2926 }
2927 return NULL;
2928 }
2929
2930 ThreadPriority JavaThread::java_priority() const {
2931 oop thr_oop = threadObj();
2932 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2933 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2934 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2935 return priority;
2936 }
2937
2938 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2939
2940 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2941 // Link Java Thread object <-> C++ Thread
2942
2943 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2944 // and put it into a new Handle. The Handle "thread_oop" can then
2945 // be used to pass the C++ thread object to other methods.
2946
2947 // Set the Java level thread object (jthread) field of the
2948 // new thread (a JavaThread *) to C++ thread object using the
2949 // "thread_oop" handle.
2950
2951 // Set the thread field (a JavaThread *) of the
2952 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2953
2954 Handle thread_oop(Thread::current(),
2955 JNIHandles::resolve_non_null(jni_thread));
2956 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2957 "must be initialized");
2958 set_threadObj(thread_oop());
2959 java_lang_Thread::set_thread(thread_oop(), this);
2960
2961 if (prio == NoPriority) {
2962 prio = java_lang_Thread::priority(thread_oop());
2963 assert(prio != NoPriority, "A valid priority should be present");
2964 }
2965
2966 // Push the Java priority down to the native thread; needs Threads_lock
2967 Thread::set_priority(this, prio);
2968
2969 prepare_ext();
2970
2971 // Add the new thread to the Threads list and set it in motion.
2972 // We must have threads lock in order to call Threads::add.
2973 // It is crucial that we do not block before the thread is
2974 // added to the Threads list for if a GC happens, then the java_thread oop
2975 // will not be visited by GC.
2976 Threads::add(this);
2977 }
2978
2979 oop JavaThread::current_park_blocker() {
2980 // Support for JSR-166 locks
2981 oop thread_oop = threadObj();
2982 if (thread_oop != NULL &&
2983 JDK_Version::current().supports_thread_park_blocker()) {
2984 return java_lang_Thread::park_blocker(thread_oop);
2985 }
2986 return NULL;
2987 }
2988
2989
2990 void JavaThread::print_stack_on(outputStream* st) {
2991 if (!has_last_Java_frame()) return;
2992 ResourceMark rm;
2993 HandleMark hm;
2994
2995 RegisterMap reg_map(this);
2996 vframe* start_vf = last_java_vframe(®_map);
2997 int count = 0;
2998 for (vframe* f = start_vf; f; f = f->sender()) {
2999 if (f->is_java_frame()) {
3000 javaVFrame* jvf = javaVFrame::cast(f);
3001 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3002
3003 // Print out lock information
3004 if (JavaMonitorsInStackTrace) {
3005 jvf->print_lock_info_on(st, count);
3006 }
3007 } else {
3008 // Ignore non-Java frames
3009 }
3010
3011 // Bail-out case for too deep stacks
3012 count++;
3013 if (MaxJavaStackTraceDepth == count) return;
3014 }
3015 }
3016
3017
3018 // JVMTI PopFrame support
3019 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3020 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3021 if (in_bytes(size_in_bytes) != 0) {
3022 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3023 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3024 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3025 }
3026 }
3027
3028 void* JavaThread::popframe_preserved_args() {
3029 return _popframe_preserved_args;
3030 }
3031
3032 ByteSize JavaThread::popframe_preserved_args_size() {
3033 return in_ByteSize(_popframe_preserved_args_size);
3034 }
3035
3036 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3037 int sz = in_bytes(popframe_preserved_args_size());
3038 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3039 return in_WordSize(sz / wordSize);
3040 }
3041
3042 void JavaThread::popframe_free_preserved_args() {
3043 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3044 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3045 _popframe_preserved_args = NULL;
3046 _popframe_preserved_args_size = 0;
3047 }
3048
3049 #ifndef PRODUCT
3050
3051 void JavaThread::trace_frames() {
3052 tty->print_cr("[Describe stack]");
3053 int frame_no = 1;
3054 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3055 tty->print(" %d. ", frame_no++);
3056 fst.current()->print_value_on(tty, this);
3057 tty->cr();
3058 }
3059 }
3060
3061 class PrintAndVerifyOopClosure: public OopClosure {
3062 protected:
3063 template <class T> inline void do_oop_work(T* p) {
3064 oop obj = oopDesc::load_decode_heap_oop(p);
3065 if (obj == NULL) return;
3066 tty->print(INTPTR_FORMAT ": ", p);
3067 if (obj->is_oop_or_null()) {
3068 if (obj->is_objArray()) {
3069 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3070 } else {
3071 obj->print();
3072 }
3073 } else {
3074 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3075 }
3076 tty->cr();
3077 }
3078 public:
3079 virtual void do_oop(oop* p) { do_oop_work(p); }
3080 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3081 };
3082
3083
3084 static void oops_print(frame* f, const RegisterMap *map) {
3085 PrintAndVerifyOopClosure print;
3086 f->print_value();
3087 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3088 }
3089
3090 // Print our all the locations that contain oops and whether they are
3091 // valid or not. This useful when trying to find the oldest frame
3092 // where an oop has gone bad since the frame walk is from youngest to
3093 // oldest.
3094 void JavaThread::trace_oops() {
3095 tty->print_cr("[Trace oops]");
3096 frames_do(oops_print);
3097 }
3098
3099
3100 #ifdef ASSERT
3101 // Print or validate the layout of stack frames
3102 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3103 ResourceMark rm;
3104 PRESERVE_EXCEPTION_MARK;
3105 FrameValues values;
3106 int frame_no = 0;
3107 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3108 fst.current()->describe(values, ++frame_no);
3109 if (depth == frame_no) break;
3110 }
3111 if (validate_only) {
3112 values.validate();
3113 } else {
3114 tty->print_cr("[Describe stack layout]");
3115 values.print(this);
3116 }
3117 }
3118 #endif
3119
3120 void JavaThread::trace_stack_from(vframe* start_vf) {
3121 ResourceMark rm;
3122 int vframe_no = 1;
3123 for (vframe* f = start_vf; f; f = f->sender()) {
3124 if (f->is_java_frame()) {
3125 javaVFrame::cast(f)->print_activation(vframe_no++);
3126 } else {
3127 f->print();
3128 }
3129 if (vframe_no > StackPrintLimit) {
3130 tty->print_cr("...<more frames>...");
3131 return;
3132 }
3133 }
3134 }
3135
3136
3137 void JavaThread::trace_stack() {
3138 if (!has_last_Java_frame()) return;
3139 ResourceMark rm;
3140 HandleMark hm;
3141 RegisterMap reg_map(this);
3142 trace_stack_from(last_java_vframe(®_map));
3143 }
3144
3145
3146 #endif // PRODUCT
3147
3148
3149 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3150 assert(reg_map != NULL, "a map must be given");
3151 frame f = last_frame();
3152 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3153 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3154 }
3155 return NULL;
3156 }
3157
3158
3159 Klass* JavaThread::security_get_caller_class(int depth) {
3160 vframeStream vfst(this);
3161 vfst.security_get_caller_frame(depth);
3162 if (!vfst.at_end()) {
3163 return vfst.method()->method_holder();
3164 }
3165 return NULL;
3166 }
3167
3168 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3169 assert(thread->is_Compiler_thread(), "must be compiler thread");
3170 CompileBroker::compiler_thread_loop();
3171 }
3172
3173 // Create a CompilerThread
3174 CompilerThread::CompilerThread(CompileQueue* queue,
3175 CompilerCounters* counters)
3176 : JavaThread(&compiler_thread_entry) {
3177 _env = NULL;
3178 _log = NULL;
3179 _task = NULL;
3180 _queue = queue;
3181 _counters = counters;
3182 _buffer_blob = NULL;
3183 _scanned_nmethod = NULL;
3184 _compiler = NULL;
3185
3186 #ifndef PRODUCT
3187 _ideal_graph_printer = NULL;
3188 #endif
3189 }
3190
3191 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3192 JavaThread::oops_do(f, cld_f, cf);
3193 if (_scanned_nmethod != NULL && cf != NULL) {
3194 // Safepoints can occur when the sweeper is scanning an nmethod so
3195 // process it here to make sure it isn't unloaded in the middle of
3196 // a scan.
3197 cf->do_code_blob(_scanned_nmethod);
3198 }
3199 }
3200
3201
3202 // ======= Threads ========
3203
3204 // The Threads class links together all active threads, and provides
3205 // operations over all threads. It is protected by its own Mutex
3206 // lock, which is also used in other contexts to protect thread
3207 // operations from having the thread being operated on from exiting
3208 // and going away unexpectedly (e.g., safepoint synchronization)
3209
3210 JavaThread* Threads::_thread_list = NULL;
3211 int Threads::_number_of_threads = 0;
3212 int Threads::_number_of_non_daemon_threads = 0;
3213 int Threads::_return_code = 0;
3214 size_t JavaThread::_stack_size_at_create = 0;
3215 #ifdef ASSERT
3216 bool Threads::_vm_complete = false;
3217 #endif
3218
3219 // All JavaThreads
3220 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3221
3222 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3223 void Threads::threads_do(ThreadClosure* tc) {
3224 assert_locked_or_safepoint(Threads_lock);
3225 // ALL_JAVA_THREADS iterates through all JavaThreads
3226 ALL_JAVA_THREADS(p) {
3227 tc->do_thread(p);
3228 }
3229 // Someday we could have a table or list of all non-JavaThreads.
3230 // For now, just manually iterate through them.
3231 tc->do_thread(VMThread::vm_thread());
3232 Universe::heap()->gc_threads_do(tc);
3233 WatcherThread *wt = WatcherThread::watcher_thread();
3234 // Strictly speaking, the following NULL check isn't sufficient to make sure
3235 // the data for WatcherThread is still valid upon being examined. However,
3236 // considering that WatchThread terminates when the VM is on the way to
3237 // exit at safepoint, the chance of the above is extremely small. The right
3238 // way to prevent termination of WatcherThread would be to acquire
3239 // Terminator_lock, but we can't do that without violating the lock rank
3240 // checking in some cases.
3241 if (wt != NULL) {
3242 tc->do_thread(wt);
3243 }
3244
3245 // If CompilerThreads ever become non-JavaThreads, add them here
3246 }
3247
3248
3249 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3250 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3251
3252 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3253 create_vm_init_libraries();
3254 }
3255
3256 initialize_class(vmSymbols::java_lang_String(), CHECK);
3257
3258 // Initialize java_lang.System (needed before creating the thread)
3259 initialize_class(vmSymbols::java_lang_System(), CHECK);
3260 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3261 Handle thread_group = create_initial_thread_group(CHECK);
3262 Universe::set_main_thread_group(thread_group());
3263 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3264 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3265 main_thread->set_threadObj(thread_object);
3266 // Set thread status to running since main thread has
3267 // been started and running.
3268 java_lang_Thread::set_thread_status(thread_object,
3269 java_lang_Thread::RUNNABLE);
3270
3271 // The VM creates & returns objects of this class. Make sure it's initialized.
3272 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3273
3274 // The VM preresolves methods to these classes. Make sure that they get initialized
3275 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3276 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3277 call_initializeSystemClass(CHECK);
3278
3279 // get the Java runtime name after java.lang.System is initialized
3280 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3281 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3282
3283 // an instance of OutOfMemory exception has been allocated earlier
3284 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3285 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3286 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3287 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3288 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3289 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3290 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3291 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3292 }
3293
3294 void Threads::initialize_jsr292_core_classes(TRAPS) {
3295 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3296 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3297 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3298 }
3299
3300 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3301 extern void JDK_Version_init();
3302
3303 // Check version
3304 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3305
3306 // Initialize the output stream module
3307 ostream_init();
3308
3309 // Process java launcher properties.
3310 Arguments::process_sun_java_launcher_properties(args);
3311
3312 // Initialize the os module before using TLS
3313 os::init();
3314
3315 // Initialize system properties.
3316 Arguments::init_system_properties();
3317
3318 // So that JDK version can be used as a discriminator when parsing arguments
3319 JDK_Version_init();
3320
3321 // Update/Initialize System properties after JDK version number is known
3322 Arguments::init_version_specific_system_properties();
3323
3324 // Parse arguments
3325 jint parse_result = Arguments::parse(args);
3326 if (parse_result != JNI_OK) return parse_result;
3327
3328 os::init_before_ergo();
3329
3330 jint ergo_result = Arguments::apply_ergo();
3331 if (ergo_result != JNI_OK) return ergo_result;
3332
3333 if (PauseAtStartup) {
3334 os::pause();
3335 }
3336
3337 HOTSPOT_VM_INIT_BEGIN();
3338
3339 // Record VM creation timing statistics
3340 TraceVmCreationTime create_vm_timer;
3341 create_vm_timer.start();
3342
3343 // Timing (must come after argument parsing)
3344 TraceTime timer("Create VM", TraceStartupTime);
3345
3346 // Initialize the os module after parsing the args
3347 jint os_init_2_result = os::init_2();
3348 if (os_init_2_result != JNI_OK) return os_init_2_result;
3349
3350 jint adjust_after_os_result = Arguments::adjust_after_os();
3351 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3352
3353 // initialize TLS
3354 ThreadLocalStorage::init();
3355
3356 // Initialize output stream logging
3357 ostream_init_log();
3358
3359 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3360 // Must be before create_vm_init_agents()
3361 if (Arguments::init_libraries_at_startup()) {
3362 convert_vm_init_libraries_to_agents();
3363 }
3364
3365 // Launch -agentlib/-agentpath and converted -Xrun agents
3366 if (Arguments::init_agents_at_startup()) {
3367 create_vm_init_agents();
3368 }
3369
3370 // Initialize Threads state
3371 _thread_list = NULL;
3372 _number_of_threads = 0;
3373 _number_of_non_daemon_threads = 0;
3374
3375 // Initialize global data structures and create system classes in heap
3376 vm_init_globals();
3377
3378 // Attach the main thread to this os thread
3379 JavaThread* main_thread = new JavaThread();
3380 main_thread->set_thread_state(_thread_in_vm);
3381 // must do this before set_active_handles and initialize_thread_local_storage
3382 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3383 // change the stack size recorded here to one based on the java thread
3384 // stacksize. This adjusted size is what is used to figure the placement
3385 // of the guard pages.
3386 main_thread->record_stack_base_and_size();
3387 main_thread->initialize_thread_local_storage();
3388
3389 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3390
3391 if (!main_thread->set_as_starting_thread()) {
3392 vm_shutdown_during_initialization(
3393 "Failed necessary internal allocation. Out of swap space");
3394 delete main_thread;
3395 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3396 return JNI_ENOMEM;
3397 }
3398
3399 // Enable guard page *after* os::create_main_thread(), otherwise it would
3400 // crash Linux VM, see notes in os_linux.cpp.
3401 main_thread->create_stack_guard_pages();
3402
3403 // Initialize Java-Level synchronization subsystem
3404 ObjectMonitor::Initialize();
3405
3406 // Initialize global modules
3407 jint status = init_globals();
3408 if (status != JNI_OK) {
3409 delete main_thread;
3410 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3411 return status;
3412 }
3413
3414 // Should be done after the heap is fully created
3415 main_thread->cache_global_variables();
3416
3417 HandleMark hm;
3418
3419 { MutexLocker mu(Threads_lock);
3420 Threads::add(main_thread);
3421 }
3422
3423 // Any JVMTI raw monitors entered in onload will transition into
3424 // real raw monitor. VM is setup enough here for raw monitor enter.
3425 JvmtiExport::transition_pending_onload_raw_monitors();
3426
3427 // Create the VMThread
3428 { TraceTime timer("Start VMThread", TraceStartupTime);
3429 VMThread::create();
3430 Thread* vmthread = VMThread::vm_thread();
3431
3432 if (!os::create_thread(vmthread, os::vm_thread)) {
3433 vm_exit_during_initialization("Cannot create VM thread. "
3434 "Out of system resources.");
3435 }
3436
3437 // Wait for the VM thread to become ready, and VMThread::run to initialize
3438 // Monitors can have spurious returns, must always check another state flag
3439 {
3440 MutexLocker ml(Notify_lock);
3441 os::start_thread(vmthread);
3442 while (vmthread->active_handles() == NULL) {
3443 Notify_lock->wait();
3444 }
3445 }
3446 }
3447
3448 assert(Universe::is_fully_initialized(), "not initialized");
3449 if (VerifyDuringStartup) {
3450 // Make sure we're starting with a clean slate.
3451 VM_Verify verify_op;
3452 VMThread::execute(&verify_op);
3453 }
3454
3455 Thread* THREAD = Thread::current();
3456
3457 // At this point, the Universe is initialized, but we have not executed
3458 // any byte code. Now is a good time (the only time) to dump out the
3459 // internal state of the JVM for sharing.
3460 if (DumpSharedSpaces) {
3461 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3462 ShouldNotReachHere();
3463 }
3464
3465 // Always call even when there are not JVMTI environments yet, since environments
3466 // may be attached late and JVMTI must track phases of VM execution
3467 JvmtiExport::enter_start_phase();
3468
3469 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3470 JvmtiExport::post_vm_start();
3471
3472 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3473
3474 // We need this for ClassDataSharing - the initial vm.info property is set
3475 // with the default value of CDS "sharing" which may be reset through
3476 // command line options.
3477 reset_vm_info_property(CHECK_JNI_ERR);
3478
3479 quicken_jni_functions();
3480
3481 // Must be run after init_ft which initializes ft_enabled
3482 if (TRACE_INITIALIZE() != JNI_OK) {
3483 vm_exit_during_initialization("Failed to initialize tracing backend");
3484 }
3485
3486 // Set flag that basic initialization has completed. Used by exceptions and various
3487 // debug stuff, that does not work until all basic classes have been initialized.
3488 set_init_completed();
3489
3490 Metaspace::post_initialize();
3491
3492 HOTSPOT_VM_INIT_END();
3493
3494 // record VM initialization completion time
3495 #if INCLUDE_MANAGEMENT
3496 Management::record_vm_init_completed();
3497 #endif // INCLUDE_MANAGEMENT
3498
3499 // Compute system loader. Note that this has to occur after set_init_completed, since
3500 // valid exceptions may be thrown in the process.
3501 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3502 // set_init_completed has just been called, causing exceptions not to be shortcut
3503 // anymore. We call vm_exit_during_initialization directly instead.
3504 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3505
3506 #if INCLUDE_ALL_GCS
3507 // Support for ConcurrentMarkSweep. This should be cleaned up
3508 // and better encapsulated. The ugly nested if test would go away
3509 // once things are properly refactored. XXX YSR
3510 if (UseConcMarkSweepGC || UseG1GC) {
3511 if (UseConcMarkSweepGC) {
3512 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3513 } else {
3514 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3515 }
3516 }
3517 #endif // INCLUDE_ALL_GCS
3518
3519 // Always call even when there are not JVMTI environments yet, since environments
3520 // may be attached late and JVMTI must track phases of VM execution
3521 JvmtiExport::enter_live_phase();
3522
3523 // Signal Dispatcher needs to be started before VMInit event is posted
3524 os::signal_init();
3525
3526 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3527 if (!DisableAttachMechanism) {
3528 AttachListener::vm_start();
3529 if (StartAttachListener || AttachListener::init_at_startup()) {
3530 AttachListener::init();
3531 }
3532 }
3533
3534 // Launch -Xrun agents
3535 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3536 // back-end can launch with -Xdebug -Xrunjdwp.
3537 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3538 create_vm_init_libraries();
3539 }
3540
3541 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3542 JvmtiExport::post_vm_initialized();
3543
3544 if (TRACE_START() != JNI_OK) {
3545 vm_exit_during_initialization("Failed to start tracing backend.");
3546 }
3547
3548 if (CleanChunkPoolAsync) {
3549 Chunk::start_chunk_pool_cleaner_task();
3550 }
3551
3552 // initialize compiler(s)
3553 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3554 CompileBroker::compilation_init();
3555 #endif
3556
3557 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3558 // It is done after compilers are initialized, because otherwise compilations of
3559 // signature polymorphic MH intrinsics can be missed
3560 // (see SystemDictionary::find_method_handle_intrinsic).
3561 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3562
3563 #if INCLUDE_MANAGEMENT
3564 Management::initialize(THREAD);
3565
3566 if (HAS_PENDING_EXCEPTION) {
3567 // management agent fails to start possibly due to
3568 // configuration problem and is responsible for printing
3569 // stack trace if appropriate. Simply exit VM.
3570 vm_exit(1);
3571 }
3572 #endif // INCLUDE_MANAGEMENT
3573
3574 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3575 if (MemProfiling) MemProfiler::engage();
3576 StatSampler::engage();
3577 if (CheckJNICalls) JniPeriodicChecker::engage();
3578
3579 BiasedLocking::init();
3580
3581 #if INCLUDE_RTM_OPT
3582 RTMLockingCounters::init();
3583 #endif
3584
3585 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3586 call_postVMInitHook(THREAD);
3587 // The Java side of PostVMInitHook.run must deal with all
3588 // exceptions and provide means of diagnosis.
3589 if (HAS_PENDING_EXCEPTION) {
3590 CLEAR_PENDING_EXCEPTION;
3591 }
3592 }
3593
3594 {
3595 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3596 // Make sure the watcher thread can be started by WatcherThread::start()
3597 // or by dynamic enrollment.
3598 WatcherThread::make_startable();
3599 // Start up the WatcherThread if there are any periodic tasks
3600 // NOTE: All PeriodicTasks should be registered by now. If they
3601 // aren't, late joiners might appear to start slowly (we might
3602 // take a while to process their first tick).
3603 if (PeriodicTask::num_tasks() > 0) {
3604 WatcherThread::start();
3605 }
3606 }
3607
3608 // Give os specific code one last chance to start
3609 os::init_3();
3610
3611 create_vm_timer.end();
3612 #ifdef ASSERT
3613 _vm_complete = true;
3614 #endif
3615 return JNI_OK;
3616 }
3617
3618 // type for the Agent_OnLoad and JVM_OnLoad entry points
3619 extern "C" {
3620 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3621 }
3622 // Find a command line agent library and return its entry point for
3623 // -agentlib: -agentpath: -Xrun
3624 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3625 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3626 const char *on_load_symbols[],
3627 size_t num_symbol_entries) {
3628 OnLoadEntry_t on_load_entry = NULL;
3629 void *library = NULL;
3630
3631 if (!agent->valid()) {
3632 char buffer[JVM_MAXPATHLEN];
3633 char ebuf[1024];
3634 const char *name = agent->name();
3635 const char *msg = "Could not find agent library ";
3636
3637 // First check to see if agent is statically linked into executable
3638 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3639 library = agent->os_lib();
3640 } else if (agent->is_absolute_path()) {
3641 library = os::dll_load(name, ebuf, sizeof ebuf);
3642 if (library == NULL) {
3643 const char *sub_msg = " in absolute path, with error: ";
3644 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3645 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3646 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3647 // If we can't find the agent, exit.
3648 vm_exit_during_initialization(buf, NULL);
3649 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3650 }
3651 } else {
3652 // Try to load the agent from the standard dll directory
3653 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3654 name)) {
3655 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3656 }
3657 if (library == NULL) { // Try the local directory
3658 char ns[1] = {0};
3659 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3660 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3661 }
3662 if (library == NULL) {
3663 const char *sub_msg = " on the library path, with error: ";
3664 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3665 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3666 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3667 // If we can't find the agent, exit.
3668 vm_exit_during_initialization(buf, NULL);
3669 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3670 }
3671 }
3672 }
3673 agent->set_os_lib(library);
3674 agent->set_valid();
3675 }
3676
3677 // Find the OnLoad function.
3678 on_load_entry =
3679 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3680 false,
3681 on_load_symbols,
3682 num_symbol_entries));
3683 return on_load_entry;
3684 }
3685
3686 // Find the JVM_OnLoad entry point
3687 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3688 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3689 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3690 }
3691
3692 // Find the Agent_OnLoad entry point
3693 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3694 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3695 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3696 }
3697
3698 // For backwards compatibility with -Xrun
3699 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3700 // treated like -agentpath:
3701 // Must be called before agent libraries are created
3702 void Threads::convert_vm_init_libraries_to_agents() {
3703 AgentLibrary* agent;
3704 AgentLibrary* next;
3705
3706 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3707 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3708 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3709
3710 // If there is an JVM_OnLoad function it will get called later,
3711 // otherwise see if there is an Agent_OnLoad
3712 if (on_load_entry == NULL) {
3713 on_load_entry = lookup_agent_on_load(agent);
3714 if (on_load_entry != NULL) {
3715 // switch it to the agent list -- so that Agent_OnLoad will be called,
3716 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3717 Arguments::convert_library_to_agent(agent);
3718 } else {
3719 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3720 }
3721 }
3722 }
3723 }
3724
3725 // Create agents for -agentlib: -agentpath: and converted -Xrun
3726 // Invokes Agent_OnLoad
3727 // Called very early -- before JavaThreads exist
3728 void Threads::create_vm_init_agents() {
3729 extern struct JavaVM_ main_vm;
3730 AgentLibrary* agent;
3731
3732 JvmtiExport::enter_onload_phase();
3733
3734 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3735 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3736
3737 if (on_load_entry != NULL) {
3738 // Invoke the Agent_OnLoad function
3739 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3740 if (err != JNI_OK) {
3741 vm_exit_during_initialization("agent library failed to init", agent->name());
3742 }
3743 } else {
3744 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3745 }
3746 }
3747 JvmtiExport::enter_primordial_phase();
3748 }
3749
3750 extern "C" {
3751 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3752 }
3753
3754 void Threads::shutdown_vm_agents() {
3755 // Send any Agent_OnUnload notifications
3756 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3757 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3758 extern struct JavaVM_ main_vm;
3759 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3760
3761 // Find the Agent_OnUnload function.
3762 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3763 os::find_agent_function(agent,
3764 false,
3765 on_unload_symbols,
3766 num_symbol_entries));
3767
3768 // Invoke the Agent_OnUnload function
3769 if (unload_entry != NULL) {
3770 JavaThread* thread = JavaThread::current();
3771 ThreadToNativeFromVM ttn(thread);
3772 HandleMark hm(thread);
3773 (*unload_entry)(&main_vm);
3774 }
3775 }
3776 }
3777
3778 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3779 // Invokes JVM_OnLoad
3780 void Threads::create_vm_init_libraries() {
3781 extern struct JavaVM_ main_vm;
3782 AgentLibrary* agent;
3783
3784 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3785 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3786
3787 if (on_load_entry != NULL) {
3788 // Invoke the JVM_OnLoad function
3789 JavaThread* thread = JavaThread::current();
3790 ThreadToNativeFromVM ttn(thread);
3791 HandleMark hm(thread);
3792 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3793 if (err != JNI_OK) {
3794 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3795 }
3796 } else {
3797 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3798 }
3799 }
3800 }
3801
3802 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3803 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3804
3805 JavaThread* java_thread = NULL;
3806 // Sequential search for now. Need to do better optimization later.
3807 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3808 oop tobj = thread->threadObj();
3809 if (!thread->is_exiting() &&
3810 tobj != NULL &&
3811 java_tid == java_lang_Thread::thread_id(tobj)) {
3812 java_thread = thread;
3813 break;
3814 }
3815 }
3816 return java_thread;
3817 }
3818
3819
3820 // Last thread running calls java.lang.Shutdown.shutdown()
3821 void JavaThread::invoke_shutdown_hooks() {
3822 HandleMark hm(this);
3823
3824 // We could get here with a pending exception, if so clear it now.
3825 if (this->has_pending_exception()) {
3826 this->clear_pending_exception();
3827 }
3828
3829 EXCEPTION_MARK;
3830 Klass* k =
3831 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3832 THREAD);
3833 if (k != NULL) {
3834 // SystemDictionary::resolve_or_null will return null if there was
3835 // an exception. If we cannot load the Shutdown class, just don't
3836 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3837 // and finalizers (if runFinalizersOnExit is set) won't be run.
3838 // Note that if a shutdown hook was registered or runFinalizersOnExit
3839 // was called, the Shutdown class would have already been loaded
3840 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3841 instanceKlassHandle shutdown_klass (THREAD, k);
3842 JavaValue result(T_VOID);
3843 JavaCalls::call_static(&result,
3844 shutdown_klass,
3845 vmSymbols::shutdown_method_name(),
3846 vmSymbols::void_method_signature(),
3847 THREAD);
3848 }
3849 CLEAR_PENDING_EXCEPTION;
3850 }
3851
3852 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3853 // the program falls off the end of main(). Another VM exit path is through
3854 // vm_exit() when the program calls System.exit() to return a value or when
3855 // there is a serious error in VM. The two shutdown paths are not exactly
3856 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3857 // and VM_Exit op at VM level.
3858 //
3859 // Shutdown sequence:
3860 // + Shutdown native memory tracking if it is on
3861 // + Wait until we are the last non-daemon thread to execute
3862 // <-- every thing is still working at this moment -->
3863 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3864 // shutdown hooks, run finalizers if finalization-on-exit
3865 // + Call before_exit(), prepare for VM exit
3866 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3867 // currently the only user of this mechanism is File.deleteOnExit())
3868 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3869 // post thread end and vm death events to JVMTI,
3870 // stop signal thread
3871 // + Call JavaThread::exit(), it will:
3872 // > release JNI handle blocks, remove stack guard pages
3873 // > remove this thread from Threads list
3874 // <-- no more Java code from this thread after this point -->
3875 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3876 // the compiler threads at safepoint
3877 // <-- do not use anything that could get blocked by Safepoint -->
3878 // + Disable tracing at JNI/JVM barriers
3879 // + Set _vm_exited flag for threads that are still running native code
3880 // + Delete this thread
3881 // + Call exit_globals()
3882 // > deletes tty
3883 // > deletes PerfMemory resources
3884 // + Return to caller
3885
3886 bool Threads::destroy_vm() {
3887 JavaThread* thread = JavaThread::current();
3888
3889 #ifdef ASSERT
3890 _vm_complete = false;
3891 #endif
3892 // Wait until we are the last non-daemon thread to execute
3893 { MutexLocker nu(Threads_lock);
3894 while (Threads::number_of_non_daemon_threads() > 1)
3895 // This wait should make safepoint checks, wait without a timeout,
3896 // and wait as a suspend-equivalent condition.
3897 //
3898 // Note: If the FlatProfiler is running and this thread is waiting
3899 // for another non-daemon thread to finish, then the FlatProfiler
3900 // is waiting for the external suspend request on this thread to
3901 // complete. wait_for_ext_suspend_completion() will eventually
3902 // timeout, but that takes time. Making this wait a suspend-
3903 // equivalent condition solves that timeout problem.
3904 //
3905 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3906 Mutex::_as_suspend_equivalent_flag);
3907 }
3908
3909 // Hang forever on exit if we are reporting an error.
3910 if (ShowMessageBoxOnError && is_error_reported()) {
3911 os::infinite_sleep();
3912 }
3913 os::wait_for_keypress_at_exit();
3914
3915 // run Java level shutdown hooks
3916 thread->invoke_shutdown_hooks();
3917
3918 before_exit(thread);
3919
3920 thread->exit(true);
3921
3922 // Stop VM thread.
3923 {
3924 // 4945125 The vm thread comes to a safepoint during exit.
3925 // GC vm_operations can get caught at the safepoint, and the
3926 // heap is unparseable if they are caught. Grab the Heap_lock
3927 // to prevent this. The GC vm_operations will not be able to
3928 // queue until after the vm thread is dead. After this point,
3929 // we'll never emerge out of the safepoint before the VM exits.
3930
3931 MutexLocker ml(Heap_lock);
3932
3933 VMThread::wait_for_vm_thread_exit();
3934 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3935 VMThread::destroy();
3936 }
3937
3938 // clean up ideal graph printers
3939 #if defined(COMPILER2) && !defined(PRODUCT)
3940 IdealGraphPrinter::clean_up();
3941 #endif
3942
3943 // Now, all Java threads are gone except daemon threads. Daemon threads
3944 // running Java code or in VM are stopped by the Safepoint. However,
3945 // daemon threads executing native code are still running. But they
3946 // will be stopped at native=>Java/VM barriers. Note that we can't
3947 // simply kill or suspend them, as it is inherently deadlock-prone.
3948
3949 #ifndef PRODUCT
3950 // disable function tracing at JNI/JVM barriers
3951 TraceJNICalls = false;
3952 TraceJVMCalls = false;
3953 TraceRuntimeCalls = false;
3954 #endif
3955
3956 VM_Exit::set_vm_exited();
3957
3958 notify_vm_shutdown();
3959
3960 delete thread;
3961
3962 // exit_globals() will delete tty
3963 exit_globals();
3964
3965 return true;
3966 }
3967
3968
3969 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3970 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3971 return is_supported_jni_version(version);
3972 }
3973
3974
3975 jboolean Threads::is_supported_jni_version(jint version) {
3976 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3977 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3978 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3979 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3980 return JNI_FALSE;
3981 }
3982
3983
3984 void Threads::add(JavaThread* p, bool force_daemon) {
3985 // The threads lock must be owned at this point
3986 assert_locked_or_safepoint(Threads_lock);
3987
3988 // See the comment for this method in thread.hpp for its purpose and
3989 // why it is called here.
3990 p->initialize_queues();
3991 p->set_next(_thread_list);
3992 _thread_list = p;
3993 _number_of_threads++;
3994 oop threadObj = p->threadObj();
3995 bool daemon = true;
3996 // Bootstrapping problem: threadObj can be null for initial
3997 // JavaThread (or for threads attached via JNI)
3998 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3999 _number_of_non_daemon_threads++;
4000 daemon = false;
4001 }
4002
4003 ThreadService::add_thread(p, daemon);
4004
4005 // Possible GC point.
4006 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4007 }
4008
4009 void Threads::remove(JavaThread* p) {
4010 // Extra scope needed for Thread_lock, so we can check
4011 // that we do not remove thread without safepoint code notice
4012 { MutexLocker ml(Threads_lock);
4013
4014 assert(includes(p), "p must be present");
4015
4016 JavaThread* current = _thread_list;
4017 JavaThread* prev = NULL;
4018
4019 while (current != p) {
4020 prev = current;
4021 current = current->next();
4022 }
4023
4024 if (prev) {
4025 prev->set_next(current->next());
4026 } else {
4027 _thread_list = p->next();
4028 }
4029 _number_of_threads--;
4030 oop threadObj = p->threadObj();
4031 bool daemon = true;
4032 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4033 _number_of_non_daemon_threads--;
4034 daemon = false;
4035
4036 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4037 // on destroy_vm will wake up.
4038 if (number_of_non_daemon_threads() == 1) {
4039 Threads_lock->notify_all();
4040 }
4041 }
4042 ThreadService::remove_thread(p, daemon);
4043
4044 // Make sure that safepoint code disregard this thread. This is needed since
4045 // the thread might mess around with locks after this point. This can cause it
4046 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4047 // of this thread since it is removed from the queue.
4048 p->set_terminated_value();
4049 } // unlock Threads_lock
4050
4051 // Since Events::log uses a lock, we grab it outside the Threads_lock
4052 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4053 }
4054
4055 // Threads_lock must be held when this is called (or must be called during a safepoint)
4056 bool Threads::includes(JavaThread* p) {
4057 assert(Threads_lock->is_locked(), "sanity check");
4058 ALL_JAVA_THREADS(q) {
4059 if (q == p) {
4060 return true;
4061 }
4062 }
4063 return false;
4064 }
4065
4066 // Operations on the Threads list for GC. These are not explicitly locked,
4067 // but the garbage collector must provide a safe context for them to run.
4068 // In particular, these things should never be called when the Threads_lock
4069 // is held by some other thread. (Note: the Safepoint abstraction also
4070 // uses the Threads_lock to guarantee this property. It also makes sure that
4071 // all threads gets blocked when exiting or starting).
4072
4073 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4074 ALL_JAVA_THREADS(p) {
4075 p->oops_do(f, cld_f, cf);
4076 }
4077 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4078 }
4079
4080 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4081 // Introduce a mechanism allowing parallel threads to claim threads as
4082 // root groups. Overhead should be small enough to use all the time,
4083 // even in sequential code.
4084 SharedHeap* sh = SharedHeap::heap();
4085 // Cannot yet substitute active_workers for n_par_threads
4086 // because of G1CollectedHeap::verify() use of
4087 // SharedHeap::process_roots(). n_par_threads == 0 will
4088 // turn off parallelism in process_roots while active_workers
4089 // is being used for parallelism elsewhere.
4090 bool is_par = sh->n_par_threads() > 0;
4091 assert(!is_par ||
4092 (SharedHeap::heap()->n_par_threads() ==
4093 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4094 int cp = SharedHeap::heap()->strong_roots_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 void Threads::deoptimized_wrt_marked_nmethods() {
4138 ALL_JAVA_THREADS(p) {
4139 p->deoptimized_wrt_marked_nmethods();
4140 }
4141 }
4142
4143
4144 // Get count Java threads that are waiting to enter the specified monitor.
4145 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4146 address monitor,
4147 bool doLock) {
4148 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4149 "must grab Threads_lock or be at safepoint");
4150 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4151
4152 int i = 0;
4153 {
4154 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4155 ALL_JAVA_THREADS(p) {
4156 if (p->is_Compiler_thread()) continue;
4157
4158 address pending = (address)p->current_pending_monitor();
4159 if (pending == monitor) { // found a match
4160 if (i < count) result->append(p); // save the first count matches
4161 i++;
4162 }
4163 }
4164 }
4165 return result;
4166 }
4167
4168
4169 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4170 bool doLock) {
4171 assert(doLock ||
4172 Threads_lock->owned_by_self() ||
4173 SafepointSynchronize::is_at_safepoint(),
4174 "must grab Threads_lock or be at safepoint");
4175
4176 // NULL owner means not locked so we can skip the search
4177 if (owner == NULL) return NULL;
4178
4179 {
4180 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4181 ALL_JAVA_THREADS(p) {
4182 // first, see if owner is the address of a Java thread
4183 if (owner == (address)p) return p;
4184 }
4185 }
4186 // Cannot assert on lack of success here since this function may be
4187 // used by code that is trying to report useful problem information
4188 // like deadlock detection.
4189 if (UseHeavyMonitors) return NULL;
4190
4191 // If we didn't find a matching Java thread and we didn't force use of
4192 // heavyweight monitors, then the owner is the stack address of the
4193 // Lock Word in the owning Java thread's stack.
4194 //
4195 JavaThread* the_owner = NULL;
4196 {
4197 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4198 ALL_JAVA_THREADS(q) {
4199 if (q->is_lock_owned(owner)) {
4200 the_owner = q;
4201 break;
4202 }
4203 }
4204 }
4205 // cannot assert on lack of success here; see above comment
4206 return the_owner;
4207 }
4208
4209 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4210 void Threads::print_on(outputStream* st, bool print_stacks,
4211 bool internal_format, bool print_concurrent_locks) {
4212 char buf[32];
4213 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4214
4215 st->print_cr("Full thread dump %s (%s %s):",
4216 Abstract_VM_Version::vm_name(),
4217 Abstract_VM_Version::vm_release(),
4218 Abstract_VM_Version::vm_info_string());
4219 st->cr();
4220
4221 #if INCLUDE_ALL_GCS
4222 // Dump concurrent locks
4223 ConcurrentLocksDump concurrent_locks;
4224 if (print_concurrent_locks) {
4225 concurrent_locks.dump_at_safepoint();
4226 }
4227 #endif // INCLUDE_ALL_GCS
4228
4229 ALL_JAVA_THREADS(p) {
4230 ResourceMark rm;
4231 p->print_on(st);
4232 if (print_stacks) {
4233 if (internal_format) {
4234 p->trace_stack();
4235 } else {
4236 p->print_stack_on(st);
4237 }
4238 }
4239 st->cr();
4240 #if INCLUDE_ALL_GCS
4241 if (print_concurrent_locks) {
4242 concurrent_locks.print_locks_on(p, st);
4243 }
4244 #endif // INCLUDE_ALL_GCS
4245 }
4246
4247 VMThread::vm_thread()->print_on(st);
4248 st->cr();
4249 Universe::heap()->print_gc_threads_on(st);
4250 WatcherThread* wt = WatcherThread::watcher_thread();
4251 if (wt != NULL) {
4252 wt->print_on(st);
4253 st->cr();
4254 }
4255 CompileBroker::print_compiler_threads_on(st);
4256 st->flush();
4257 }
4258
4259 // Threads::print_on_error() is called by fatal error handler. It's possible
4260 // that VM is not at safepoint and/or current thread is inside signal handler.
4261 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4262 // memory (even in resource area), it might deadlock the error handler.
4263 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4264 int buflen) {
4265 bool found_current = false;
4266 st->print_cr("Java Threads: ( => current thread )");
4267 ALL_JAVA_THREADS(thread) {
4268 bool is_current = (current == thread);
4269 found_current = found_current || is_current;
4270
4271 st->print("%s", is_current ? "=>" : " ");
4272
4273 st->print(PTR_FORMAT, thread);
4274 st->print(" ");
4275 thread->print_on_error(st, buf, buflen);
4276 st->cr();
4277 }
4278 st->cr();
4279
4280 st->print_cr("Other Threads:");
4281 if (VMThread::vm_thread()) {
4282 bool is_current = (current == VMThread::vm_thread());
4283 found_current = found_current || is_current;
4284 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4285
4286 st->print(PTR_FORMAT, VMThread::vm_thread());
4287 st->print(" ");
4288 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4289 st->cr();
4290 }
4291 WatcherThread* wt = WatcherThread::watcher_thread();
4292 if (wt != NULL) {
4293 bool is_current = (current == wt);
4294 found_current = found_current || is_current;
4295 st->print("%s", is_current ? "=>" : " ");
4296
4297 st->print(PTR_FORMAT, wt);
4298 st->print(" ");
4299 wt->print_on_error(st, buf, buflen);
4300 st->cr();
4301 }
4302 if (!found_current) {
4303 st->cr();
4304 st->print("=>" PTR_FORMAT " (exited) ", current);
4305 current->print_on_error(st, buf, buflen);
4306 st->cr();
4307 }
4308 }
4309
4310 // Internal SpinLock and Mutex
4311 // Based on ParkEvent
4312
4313 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4314 //
4315 // We employ SpinLocks _only for low-contention, fixed-length
4316 // short-duration critical sections where we're concerned
4317 // about native mutex_t or HotSpot Mutex:: latency.
4318 // The mux construct provides a spin-then-block mutual exclusion
4319 // mechanism.
4320 //
4321 // Testing has shown that contention on the ListLock guarding gFreeList
4322 // is common. If we implement ListLock as a simple SpinLock it's common
4323 // for the JVM to devolve to yielding with little progress. This is true
4324 // despite the fact that the critical sections protected by ListLock are
4325 // extremely short.
4326 //
4327 // TODO-FIXME: ListLock should be of type SpinLock.
4328 // We should make this a 1st-class type, integrated into the lock
4329 // hierarchy as leaf-locks. Critically, the SpinLock structure
4330 // should have sufficient padding to avoid false-sharing and excessive
4331 // cache-coherency traffic.
4332
4333
4334 typedef volatile int SpinLockT;
4335
4336 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4337 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4338 return; // normal fast-path return
4339 }
4340
4341 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4342 TEVENT(SpinAcquire - ctx);
4343 int ctr = 0;
4344 int Yields = 0;
4345 for (;;) {
4346 while (*adr != 0) {
4347 ++ctr;
4348 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4349 if (Yields > 5) {
4350 os::naked_short_sleep(1);
4351 } else {
4352 os::naked_yield();
4353 ++Yields;
4354 }
4355 } else {
4356 SpinPause();
4357 }
4358 }
4359 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4360 }
4361 }
4362
4363 void Thread::SpinRelease(volatile int * adr) {
4364 assert(*adr != 0, "invariant");
4365 OrderAccess::fence(); // guarantee at least release consistency.
4366 // Roach-motel semantics.
4367 // It's safe if subsequent LDs and STs float "up" into the critical section,
4368 // but prior LDs and STs within the critical section can't be allowed
4369 // to reorder or float past the ST that releases the lock.
4370 // Loads and stores in the critical section - which appear in program
4371 // order before the store that releases the lock - must also appear
4372 // before the store that releases the lock in memory visibility order.
4373 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4374 // the ST of 0 into the lock-word which releases the lock, so fence
4375 // more than covers this on all platforms.
4376 *adr = 0;
4377 }
4378
4379 // muxAcquire and muxRelease:
4380 //
4381 // * muxAcquire and muxRelease support a single-word lock-word construct.
4382 // The LSB of the word is set IFF the lock is held.
4383 // The remainder of the word points to the head of a singly-linked list
4384 // of threads blocked on the lock.
4385 //
4386 // * The current implementation of muxAcquire-muxRelease uses its own
4387 // dedicated Thread._MuxEvent instance. If we're interested in
4388 // minimizing the peak number of extant ParkEvent instances then
4389 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4390 // as certain invariants were satisfied. Specifically, care would need
4391 // to be taken with regards to consuming unpark() "permits".
4392 // A safe rule of thumb is that a thread would never call muxAcquire()
4393 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4394 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4395 // consume an unpark() permit intended for monitorenter, for instance.
4396 // One way around this would be to widen the restricted-range semaphore
4397 // implemented in park(). Another alternative would be to provide
4398 // multiple instances of the PlatformEvent() for each thread. One
4399 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4400 //
4401 // * Usage:
4402 // -- Only as leaf locks
4403 // -- for short-term locking only as muxAcquire does not perform
4404 // thread state transitions.
4405 //
4406 // Alternatives:
4407 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4408 // but with parking or spin-then-park instead of pure spinning.
4409 // * Use Taura-Oyama-Yonenzawa locks.
4410 // * It's possible to construct a 1-0 lock if we encode the lockword as
4411 // (List,LockByte). Acquire will CAS the full lockword while Release
4412 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4413 // acquiring threads use timers (ParkTimed) to detect and recover from
4414 // the stranding window. Thread/Node structures must be aligned on 256-byte
4415 // boundaries by using placement-new.
4416 // * Augment MCS with advisory back-link fields maintained with CAS().
4417 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4418 // The validity of the backlinks must be ratified before we trust the value.
4419 // If the backlinks are invalid the exiting thread must back-track through the
4420 // the forward links, which are always trustworthy.
4421 // * Add a successor indication. The LockWord is currently encoded as
4422 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4423 // to provide the usual futile-wakeup optimization.
4424 // See RTStt for details.
4425 // * Consider schedctl.sc_nopreempt to cover the critical section.
4426 //
4427
4428
4429 typedef volatile intptr_t MutexT; // Mux Lock-word
4430 enum MuxBits { LOCKBIT = 1 };
4431
4432 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4433 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4434 if (w == 0) return;
4435 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4436 return;
4437 }
4438
4439 TEVENT(muxAcquire - Contention);
4440 ParkEvent * const Self = Thread::current()->_MuxEvent;
4441 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4442 for (;;) {
4443 int its = (os::is_MP() ? 100 : 0) + 1;
4444
4445 // Optional spin phase: spin-then-park strategy
4446 while (--its >= 0) {
4447 w = *Lock;
4448 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4449 return;
4450 }
4451 }
4452
4453 Self->reset();
4454 Self->OnList = intptr_t(Lock);
4455 // The following fence() isn't _strictly necessary as the subsequent
4456 // CAS() both serializes execution and ratifies the fetched *Lock value.
4457 OrderAccess::fence();
4458 for (;;) {
4459 w = *Lock;
4460 if ((w & LOCKBIT) == 0) {
4461 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4462 Self->OnList = 0; // hygiene - allows stronger asserts
4463 return;
4464 }
4465 continue; // Interference -- *Lock changed -- Just retry
4466 }
4467 assert(w & LOCKBIT, "invariant");
4468 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4469 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4470 }
4471
4472 while (Self->OnList != 0) {
4473 Self->park();
4474 }
4475 }
4476 }
4477
4478 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4479 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4480 if (w == 0) return;
4481 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4482 return;
4483 }
4484
4485 TEVENT(muxAcquire - Contention);
4486 ParkEvent * ReleaseAfter = NULL;
4487 if (ev == NULL) {
4488 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4489 }
4490 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4491 for (;;) {
4492 guarantee(ev->OnList == 0, "invariant");
4493 int its = (os::is_MP() ? 100 : 0) + 1;
4494
4495 // Optional spin phase: spin-then-park strategy
4496 while (--its >= 0) {
4497 w = *Lock;
4498 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4499 if (ReleaseAfter != NULL) {
4500 ParkEvent::Release(ReleaseAfter);
4501 }
4502 return;
4503 }
4504 }
4505
4506 ev->reset();
4507 ev->OnList = intptr_t(Lock);
4508 // The following fence() isn't _strictly necessary as the subsequent
4509 // CAS() both serializes execution and ratifies the fetched *Lock value.
4510 OrderAccess::fence();
4511 for (;;) {
4512 w = *Lock;
4513 if ((w & LOCKBIT) == 0) {
4514 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4515 ev->OnList = 0;
4516 // We call ::Release while holding the outer lock, thus
4517 // artificially lengthening the critical section.
4518 // Consider deferring the ::Release() until the subsequent unlock(),
4519 // after we've dropped the outer lock.
4520 if (ReleaseAfter != NULL) {
4521 ParkEvent::Release(ReleaseAfter);
4522 }
4523 return;
4524 }
4525 continue; // Interference -- *Lock changed -- Just retry
4526 }
4527 assert(w & LOCKBIT, "invariant");
4528 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4529 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4530 }
4531
4532 while (ev->OnList != 0) {
4533 ev->park();
4534 }
4535 }
4536 }
4537
4538 // Release() must extract a successor from the list and then wake that thread.
4539 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4540 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4541 // Release() would :
4542 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4543 // (B) Extract a successor from the private list "in-hand"
4544 // (C) attempt to CAS() the residual back into *Lock over null.
4545 // If there were any newly arrived threads and the CAS() would fail.
4546 // In that case Release() would detach the RATs, re-merge the list in-hand
4547 // with the RATs and repeat as needed. Alternately, Release() might
4548 // detach and extract a successor, but then pass the residual list to the wakee.
4549 // The wakee would be responsible for reattaching and remerging before it
4550 // competed for the lock.
4551 //
4552 // Both "pop" and DMR are immune from ABA corruption -- there can be
4553 // multiple concurrent pushers, but only one popper or detacher.
4554 // This implementation pops from the head of the list. This is unfair,
4555 // but tends to provide excellent throughput as hot threads remain hot.
4556 // (We wake recently run threads first).
4557 //
4558 // All paths through muxRelease() will execute a CAS.
4559 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4560 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4561 // executed within the critical section are complete and globally visible before the
4562 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4563 void Thread::muxRelease(volatile intptr_t * Lock) {
4564 for (;;) {
4565 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4566 assert(w & LOCKBIT, "invariant");
4567 if (w == LOCKBIT) return;
4568 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4569 assert(List != NULL, "invariant");
4570 assert(List->OnList == intptr_t(Lock), "invariant");
4571 ParkEvent * const nxt = List->ListNext;
4572 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4573
4574 // The following CAS() releases the lock and pops the head element.
4575 // The CAS() also ratifies the previously fetched lock-word value.
4576 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4577 continue;
4578 }
4579 List->OnList = 0;
4580 OrderAccess::fence();
4581 List->unpark();
4582 return;
4583 }
4584 }
4585
4586
4587 void Threads::verify() {
4588 ALL_JAVA_THREADS(p) {
4589 p->verify();
4590 }
4591 VMThread* thread = VMThread::vm_thread();
4592 if (thread != NULL) thread->verify();
4593 }