1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/scopeDesc.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "interpreter/linkResolver.hpp"
35 #include "interpreter/oopMapCache.hpp"
36 #include "jvmtifiles/jvmtiEnv.hpp"
37 #include "memory/gcLocker.inline.hpp"
38 #include "memory/metaspaceShared.hpp"
39 #include "memory/oopFactory.hpp"
40 #include "memory/universe.inline.hpp"
41 #include "oops/instanceKlass.hpp"
42 #include "oops/objArrayOop.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "oops/symbol.hpp"
45 #include "oops/verifyOopClosure.hpp"
46 #include "prims/jvm_misc.hpp"
47 #include "prims/jvmtiExport.hpp"
48 #include "prims/jvmtiThreadState.hpp"
49 #include "prims/privilegedStack.hpp"
50 #include "runtime/arguments.hpp"
51 #include "runtime/atomic.inline.hpp"
52 #include "runtime/biasedLocking.hpp"
53 #include "runtime/deoptimization.hpp"
54 #include "runtime/fprofiler.hpp"
55 #include "runtime/frame.inline.hpp"
56 #include "runtime/init.hpp"
57 #include "runtime/interfaceSupport.hpp"
58 #include "runtime/java.hpp"
59 #include "runtime/javaCalls.hpp"
60 #include "runtime/jniPeriodicChecker.hpp"
61 #include "runtime/memprofiler.hpp"
62 #include "runtime/mutexLocker.hpp"
63 #include "runtime/objectMonitor.hpp"
64 #include "runtime/orderAccess.inline.hpp"
65 #include "runtime/osThread.hpp"
66 #include "runtime/safepoint.hpp"
67 #include "runtime/sharedRuntime.hpp"
68 #include "runtime/statSampler.hpp"
69 #include "runtime/stubRoutines.hpp"
70 #include "runtime/sweeper.hpp"
71 #include "runtime/task.hpp"
72 #include "runtime/thread.inline.hpp"
73 #include "runtime/threadCritical.hpp"
74 #include "runtime/threadLocalStorage.hpp"
75 #include "runtime/vframe.hpp"
76 #include "runtime/vframeArray.hpp"
77 #include "runtime/vframe_hp.hpp"
78 #include "runtime/vmThread.hpp"
79 #include "runtime/vm_operations.hpp"
80 #include "runtime/vm_version.hpp"
81 #include "services/attachListener.hpp"
82 #include "services/management.hpp"
83 #include "services/memTracker.hpp"
84 #include "services/threadService.hpp"
85 #include "trace/tracing.hpp"
86 #include "trace/traceMacros.hpp"
87 #include "utilities/defaultStream.hpp"
88 #include "utilities/dtrace.hpp"
89 #include "utilities/events.hpp"
90 #include "utilities/preserveException.hpp"
91 #include "utilities/macros.hpp"
92 #if INCLUDE_ALL_GCS
93 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
94 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
95 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
96 #endif // INCLUDE_ALL_GCS
97 #ifdef COMPILER1
98 #include "c1/c1_Compiler.hpp"
99 #endif
100 #ifdef COMPILER2
101 #include "opto/c2compiler.hpp"
102 #include "opto/idealGraphPrinter.hpp"
103 #endif
104 #if INCLUDE_RTM_OPT
105 #include "runtime/rtmLocking.hpp"
106 #endif
107
108 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
109
110 #ifdef DTRACE_ENABLED
111
112 // Only bother with this argument setup if dtrace is available
113
114 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
115 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
116
117 #define DTRACE_THREAD_PROBE(probe, javathread) \
118 { \
119 ResourceMark rm(this); \
120 int len = 0; \
121 const char* name = (javathread)->get_thread_name(); \
122 len = strlen(name); \
123 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
124 (char *) name, len, \
125 java_lang_Thread::thread_id((javathread)->threadObj()), \
126 (uintptr_t) (javathread)->osthread()->thread_id(), \
127 java_lang_Thread::is_daemon((javathread)->threadObj())); \
128 }
129
130 #else // ndef DTRACE_ENABLED
131
132 #define DTRACE_THREAD_PROBE(probe, javathread)
133
134 #endif // ndef DTRACE_ENABLED
135
136
137 // Class hierarchy
138 // - Thread
139 // - VMThread
140 // - WatcherThread
141 // - ConcurrentMarkSweepThread
142 // - JavaThread
143 // - CompilerThread
144
145 // ======= Thread ========
146 // Support for forcing alignment of thread objects for biased locking
147 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
148 if (UseBiasedLocking) {
149 const int alignment = markOopDesc::biased_lock_alignment;
150 size_t aligned_size = size + (alignment - sizeof(intptr_t));
151 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
152 : AllocateHeap(aligned_size, flags, CURRENT_PC,
153 AllocFailStrategy::RETURN_NULL);
154 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
155 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
156 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
157 "JavaThread alignment code overflowed allocated storage");
158 if (TraceBiasedLocking) {
159 if (aligned_addr != real_malloc_addr) {
160 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
161 real_malloc_addr, aligned_addr);
162 }
163 }
164 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
165 return aligned_addr;
166 } else {
167 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
168 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
169 }
170 }
171
172 void Thread::operator delete(void* p) {
173 if (UseBiasedLocking) {
174 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
175 FreeHeap(real_malloc_addr);
176 } else {
177 FreeHeap(p);
178 }
179 }
180
181
182 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
183 // JavaThread
184
185
186 Thread::Thread() {
187 // stack and get_thread
188 set_stack_base(NULL);
189 set_stack_size(0);
190 set_self_raw_id(0);
191 set_lgrp_id(-1);
192
193 // allocated data structures
194 set_osthread(NULL);
195 set_resource_area(new (mtThread)ResourceArea());
196 DEBUG_ONLY(_current_resource_mark = NULL;)
197 set_handle_area(new (mtThread) HandleArea(NULL));
198 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
199 set_active_handles(NULL);
200 set_free_handle_block(NULL);
201 set_last_handle_mark(NULL);
202
203 // This initial value ==> never claimed.
204 _oops_do_parity = 0;
205
206 _metadata_on_stack_buffer = NULL;
207
208 // the handle mark links itself to last_handle_mark
209 new HandleMark(this);
210
211 // plain initialization
212 debug_only(_owned_locks = NULL;)
213 debug_only(_allow_allocation_count = 0;)
214 NOT_PRODUCT(_allow_safepoint_count = 0;)
215 NOT_PRODUCT(_skip_gcalot = false;)
216 _jvmti_env_iteration_count = 0;
217 set_allocated_bytes(0);
218 _vm_operation_started_count = 0;
219 _vm_operation_completed_count = 0;
220 _current_pending_monitor = NULL;
221 _current_pending_monitor_is_from_java = true;
222 _current_waiting_monitor = NULL;
223 _num_nested_signal = 0;
224 omFreeList = NULL;
225 omFreeCount = 0;
226 omFreeProvision = 32;
227 omInUseList = NULL;
228 omInUseCount = 0;
229
230 #ifdef ASSERT
231 _visited_for_critical_count = false;
232 #endif
233
234 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
235 Monitor::_safepoint_check_sometimes);
236 _suspend_flags = 0;
237
238 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
239 _hashStateX = os::random();
240 _hashStateY = 842502087;
241 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
242 _hashStateW = 273326509;
243
244 _OnTrap = 0;
245 _schedctl = NULL;
246 _Stalled = 0;
247 _TypeTag = 0x2BAD;
248
249 // Many of the following fields are effectively final - immutable
250 // Note that nascent threads can't use the Native Monitor-Mutex
251 // construct until the _MutexEvent is initialized ...
252 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
253 // we might instead use a stack of ParkEvents that we could provision on-demand.
254 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
255 // and ::Release()
256 _ParkEvent = ParkEvent::Allocate(this);
257 _SleepEvent = ParkEvent::Allocate(this);
258 _MutexEvent = ParkEvent::Allocate(this);
259 _MuxEvent = ParkEvent::Allocate(this);
260
261 #ifdef CHECK_UNHANDLED_OOPS
262 if (CheckUnhandledOops) {
263 _unhandled_oops = new UnhandledOops(this);
264 }
265 #endif // CHECK_UNHANDLED_OOPS
266 #ifdef ASSERT
267 if (UseBiasedLocking) {
268 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
269 assert(this == _real_malloc_address ||
270 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
271 "bug in forced alignment of thread objects");
272 }
273 #endif // ASSERT
274 }
275
276 void Thread::initialize_thread_local_storage() {
277 // Note: Make sure this method only calls
278 // non-blocking operations. Otherwise, it might not work
279 // with the thread-startup/safepoint interaction.
280
281 // During Java thread startup, safepoint code should allow this
282 // method to complete because it may need to allocate memory to
283 // store information for the new thread.
284
285 // initialize structure dependent on thread local storage
286 ThreadLocalStorage::set_thread(this);
287 }
288
289 void Thread::record_stack_base_and_size() {
290 set_stack_base(os::current_stack_base());
291 set_stack_size(os::current_stack_size());
292 if (is_Java_thread()) {
293 ((JavaThread*) this)->set_stack_overflow_limit();
294 }
295 // CR 7190089: on Solaris, primordial thread's stack is adjusted
296 // in initialize_thread(). Without the adjustment, stack size is
297 // incorrect if stack is set to unlimited (ulimit -s unlimited).
298 // So far, only Solaris has real implementation of initialize_thread().
299 //
300 // set up any platform-specific state.
301 os::initialize_thread(this);
302
303 #if INCLUDE_NMT
304 // record thread's native stack, stack grows downward
305 address stack_low_addr = stack_base() - stack_size();
306 MemTracker::record_thread_stack(stack_low_addr, stack_size());
307 #endif // INCLUDE_NMT
308 }
309
310
311 Thread::~Thread() {
312 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
313 ObjectSynchronizer::omFlush(this);
314
315 EVENT_THREAD_DESTRUCT(this);
316
317 // stack_base can be NULL if the thread is never started or exited before
318 // record_stack_base_and_size called. Although, we would like to ensure
319 // that all started threads do call record_stack_base_and_size(), there is
320 // not proper way to enforce that.
321 #if INCLUDE_NMT
322 if (_stack_base != NULL) {
323 address low_stack_addr = stack_base() - stack_size();
324 MemTracker::release_thread_stack(low_stack_addr, stack_size());
325 #ifdef ASSERT
326 set_stack_base(NULL);
327 #endif
328 }
329 #endif // INCLUDE_NMT
330
331 // deallocate data structures
332 delete resource_area();
333 // since the handle marks are using the handle area, we have to deallocated the root
334 // handle mark before deallocating the thread's handle area,
335 assert(last_handle_mark() != NULL, "check we have an element");
336 delete last_handle_mark();
337 assert(last_handle_mark() == NULL, "check we have reached the end");
338
339 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
340 // We NULL out the fields for good hygiene.
341 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
342 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
343 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
344 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
345
346 delete handle_area();
347 delete metadata_handles();
348
349 // osthread() can be NULL, if creation of thread failed.
350 if (osthread() != NULL) os::free_thread(osthread());
351
352 delete _SR_lock;
353
354 // clear thread local storage if the Thread is deleting itself
355 if (this == Thread::current()) {
356 ThreadLocalStorage::set_thread(NULL);
357 } else {
358 // In the case where we're not the current thread, invalidate all the
359 // caches in case some code tries to get the current thread or the
360 // thread that was destroyed, and gets stale information.
361 ThreadLocalStorage::invalidate_all();
362 }
363 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
364 }
365
366 // NOTE: dummy function for assertion purpose.
367 void Thread::run() {
368 ShouldNotReachHere();
369 }
370
371 #ifdef ASSERT
372 // Private method to check for dangling thread pointer
373 void check_for_dangling_thread_pointer(Thread *thread) {
374 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
375 "possibility of dangling Thread pointer");
376 }
377 #endif
378
379 ThreadPriority Thread::get_priority(const Thread* const thread) {
380 ThreadPriority priority;
381 // Can return an error!
382 (void)os::get_priority(thread, priority);
383 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
384 return priority;
385 }
386
387 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
388 debug_only(check_for_dangling_thread_pointer(thread);)
389 // Can return an error!
390 (void)os::set_priority(thread, priority);
391 }
392
393
394 void Thread::start(Thread* thread) {
395 // Start is different from resume in that its safety is guaranteed by context or
396 // being called from a Java method synchronized on the Thread object.
397 if (!DisableStartThread) {
398 if (thread->is_Java_thread()) {
399 // Initialize the thread state to RUNNABLE before starting this thread.
400 // Can not set it after the thread started because we do not know the
401 // exact thread state at that time. It could be in MONITOR_WAIT or
402 // in SLEEPING or some other state.
403 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
404 java_lang_Thread::RUNNABLE);
405 }
406 os::start_thread(thread);
407 }
408 }
409
410 // Enqueue a VM_Operation to do the job for us - sometime later
411 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
412 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
413 VMThread::execute(vm_stop);
414 }
415
416
417 // Check if an external suspend request has completed (or has been
418 // cancelled). Returns true if the thread is externally suspended and
419 // false otherwise.
420 //
421 // The bits parameter returns information about the code path through
422 // the routine. Useful for debugging:
423 //
424 // set in is_ext_suspend_completed():
425 // 0x00000001 - routine was entered
426 // 0x00000010 - routine return false at end
427 // 0x00000100 - thread exited (return false)
428 // 0x00000200 - suspend request cancelled (return false)
429 // 0x00000400 - thread suspended (return true)
430 // 0x00001000 - thread is in a suspend equivalent state (return true)
431 // 0x00002000 - thread is native and walkable (return true)
432 // 0x00004000 - thread is native_trans and walkable (needed retry)
433 //
434 // set in wait_for_ext_suspend_completion():
435 // 0x00010000 - routine was entered
436 // 0x00020000 - suspend request cancelled before loop (return false)
437 // 0x00040000 - thread suspended before loop (return true)
438 // 0x00080000 - suspend request cancelled in loop (return false)
439 // 0x00100000 - thread suspended in loop (return true)
440 // 0x00200000 - suspend not completed during retry loop (return false)
441
442 // Helper class for tracing suspend wait debug bits.
443 //
444 // 0x00000100 indicates that the target thread exited before it could
445 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
446 // 0x00080000 each indicate a cancelled suspend request so they don't
447 // count as wait failures either.
448 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
449
450 class TraceSuspendDebugBits : public StackObj {
451 private:
452 JavaThread * jt;
453 bool is_wait;
454 bool called_by_wait; // meaningful when !is_wait
455 uint32_t * bits;
456
457 public:
458 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
459 uint32_t *_bits) {
460 jt = _jt;
461 is_wait = _is_wait;
462 called_by_wait = _called_by_wait;
463 bits = _bits;
464 }
465
466 ~TraceSuspendDebugBits() {
467 if (!is_wait) {
468 #if 1
469 // By default, don't trace bits for is_ext_suspend_completed() calls.
470 // That trace is very chatty.
471 return;
472 #else
473 if (!called_by_wait) {
474 // If tracing for is_ext_suspend_completed() is enabled, then only
475 // trace calls to it from wait_for_ext_suspend_completion()
476 return;
477 }
478 #endif
479 }
480
481 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
482 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
483 MutexLocker ml(Threads_lock); // needed for get_thread_name()
484 ResourceMark rm;
485
486 tty->print_cr(
487 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
488 jt->get_thread_name(), *bits);
489
490 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
491 }
492 }
493 }
494 };
495 #undef DEBUG_FALSE_BITS
496
497
498 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
499 uint32_t *bits) {
500 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
501
502 bool did_trans_retry = false; // only do thread_in_native_trans retry once
503 bool do_trans_retry; // flag to force the retry
504
505 *bits |= 0x00000001;
506
507 do {
508 do_trans_retry = false;
509
510 if (is_exiting()) {
511 // Thread is in the process of exiting. This is always checked
512 // first to reduce the risk of dereferencing a freed JavaThread.
513 *bits |= 0x00000100;
514 return false;
515 }
516
517 if (!is_external_suspend()) {
518 // Suspend request is cancelled. This is always checked before
519 // is_ext_suspended() to reduce the risk of a rogue resume
520 // confusing the thread that made the suspend request.
521 *bits |= 0x00000200;
522 return false;
523 }
524
525 if (is_ext_suspended()) {
526 // thread is suspended
527 *bits |= 0x00000400;
528 return true;
529 }
530
531 // Now that we no longer do hard suspends of threads running
532 // native code, the target thread can be changing thread state
533 // while we are in this routine:
534 //
535 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
536 //
537 // We save a copy of the thread state as observed at this moment
538 // and make our decision about suspend completeness based on the
539 // copy. This closes the race where the thread state is seen as
540 // _thread_in_native_trans in the if-thread_blocked check, but is
541 // seen as _thread_blocked in if-thread_in_native_trans check.
542 JavaThreadState save_state = thread_state();
543
544 if (save_state == _thread_blocked && is_suspend_equivalent()) {
545 // If the thread's state is _thread_blocked and this blocking
546 // condition is known to be equivalent to a suspend, then we can
547 // consider the thread to be externally suspended. This means that
548 // the code that sets _thread_blocked has been modified to do
549 // self-suspension if the blocking condition releases. We also
550 // used to check for CONDVAR_WAIT here, but that is now covered by
551 // the _thread_blocked with self-suspension check.
552 //
553 // Return true since we wouldn't be here unless there was still an
554 // external suspend request.
555 *bits |= 0x00001000;
556 return true;
557 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
558 // Threads running native code will self-suspend on native==>VM/Java
559 // transitions. If its stack is walkable (should always be the case
560 // unless this function is called before the actual java_suspend()
561 // call), then the wait is done.
562 *bits |= 0x00002000;
563 return true;
564 } else if (!called_by_wait && !did_trans_retry &&
565 save_state == _thread_in_native_trans &&
566 frame_anchor()->walkable()) {
567 // The thread is transitioning from thread_in_native to another
568 // thread state. check_safepoint_and_suspend_for_native_trans()
569 // will force the thread to self-suspend. If it hasn't gotten
570 // there yet we may have caught the thread in-between the native
571 // code check above and the self-suspend. Lucky us. If we were
572 // called by wait_for_ext_suspend_completion(), then it
573 // will be doing the retries so we don't have to.
574 //
575 // Since we use the saved thread state in the if-statement above,
576 // there is a chance that the thread has already transitioned to
577 // _thread_blocked by the time we get here. In that case, we will
578 // make a single unnecessary pass through the logic below. This
579 // doesn't hurt anything since we still do the trans retry.
580
581 *bits |= 0x00004000;
582
583 // Once the thread leaves thread_in_native_trans for another
584 // thread state, we break out of this retry loop. We shouldn't
585 // need this flag to prevent us from getting back here, but
586 // sometimes paranoia is good.
587 did_trans_retry = true;
588
589 // We wait for the thread to transition to a more usable state.
590 for (int i = 1; i <= SuspendRetryCount; i++) {
591 // We used to do an "os::yield_all(i)" call here with the intention
592 // that yielding would increase on each retry. However, the parameter
593 // is ignored on Linux which means the yield didn't scale up. Waiting
594 // on the SR_lock below provides a much more predictable scale up for
595 // the delay. It also provides a simple/direct point to check for any
596 // safepoint requests from the VMThread
597
598 // temporarily drops SR_lock while doing wait with safepoint check
599 // (if we're a JavaThread - the WatcherThread can also call this)
600 // and increase delay with each retry
601 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
602
603 // check the actual thread state instead of what we saved above
604 if (thread_state() != _thread_in_native_trans) {
605 // the thread has transitioned to another thread state so
606 // try all the checks (except this one) one more time.
607 do_trans_retry = true;
608 break;
609 }
610 } // end retry loop
611
612
613 }
614 } while (do_trans_retry);
615
616 *bits |= 0x00000010;
617 return false;
618 }
619
620 // Wait for an external suspend request to complete (or be cancelled).
621 // Returns true if the thread is externally suspended and false otherwise.
622 //
623 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
624 uint32_t *bits) {
625 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
626 false /* !called_by_wait */, bits);
627
628 // local flag copies to minimize SR_lock hold time
629 bool is_suspended;
630 bool pending;
631 uint32_t reset_bits;
632
633 // set a marker so is_ext_suspend_completed() knows we are the caller
634 *bits |= 0x00010000;
635
636 // We use reset_bits to reinitialize the bits value at the top of
637 // each retry loop. This allows the caller to make use of any
638 // unused bits for their own marking purposes.
639 reset_bits = *bits;
640
641 {
642 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
643 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
644 delay, bits);
645 pending = is_external_suspend();
646 }
647 // must release SR_lock to allow suspension to complete
648
649 if (!pending) {
650 // A cancelled suspend request is the only false return from
651 // is_ext_suspend_completed() that keeps us from entering the
652 // retry loop.
653 *bits |= 0x00020000;
654 return false;
655 }
656
657 if (is_suspended) {
658 *bits |= 0x00040000;
659 return true;
660 }
661
662 for (int i = 1; i <= retries; i++) {
663 *bits = reset_bits; // reinit to only track last retry
664
665 // We used to do an "os::yield_all(i)" call here with the intention
666 // that yielding would increase on each retry. However, the parameter
667 // is ignored on Linux which means the yield didn't scale up. Waiting
668 // on the SR_lock below provides a much more predictable scale up for
669 // the delay. It also provides a simple/direct point to check for any
670 // safepoint requests from the VMThread
671
672 {
673 MutexLocker ml(SR_lock());
674 // wait with safepoint check (if we're a JavaThread - the WatcherThread
675 // can also call this) and increase delay with each retry
676 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
677
678 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
679 delay, bits);
680
681 // It is possible for the external suspend request to be cancelled
682 // (by a resume) before the actual suspend operation is completed.
683 // Refresh our local copy to see if we still need to wait.
684 pending = is_external_suspend();
685 }
686
687 if (!pending) {
688 // A cancelled suspend request is the only false return from
689 // is_ext_suspend_completed() that keeps us from staying in the
690 // retry loop.
691 *bits |= 0x00080000;
692 return false;
693 }
694
695 if (is_suspended) {
696 *bits |= 0x00100000;
697 return true;
698 }
699 } // end retry loop
700
701 // thread did not suspend after all our retries
702 *bits |= 0x00200000;
703 return false;
704 }
705
706 #ifndef PRODUCT
707 void JavaThread::record_jump(address target, address instr, const char* file,
708 int line) {
709
710 // This should not need to be atomic as the only way for simultaneous
711 // updates is via interrupts. Even then this should be rare or non-existent
712 // and we don't care that much anyway.
713
714 int index = _jmp_ring_index;
715 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
716 _jmp_ring[index]._target = (intptr_t) target;
717 _jmp_ring[index]._instruction = (intptr_t) instr;
718 _jmp_ring[index]._file = file;
719 _jmp_ring[index]._line = line;
720 }
721 #endif // PRODUCT
722
723 // Called by flat profiler
724 // Callers have already called wait_for_ext_suspend_completion
725 // The assertion for that is currently too complex to put here:
726 bool JavaThread::profile_last_Java_frame(frame* _fr) {
727 bool gotframe = false;
728 // self suspension saves needed state.
729 if (has_last_Java_frame() && _anchor.walkable()) {
730 *_fr = pd_last_frame();
731 gotframe = true;
732 }
733 return gotframe;
734 }
735
736 void Thread::interrupt(Thread* thread) {
737 debug_only(check_for_dangling_thread_pointer(thread);)
738 os::interrupt(thread);
739 }
740
741 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
742 debug_only(check_for_dangling_thread_pointer(thread);)
743 // Note: If clear_interrupted==false, this simply fetches and
744 // returns the value of the field osthread()->interrupted().
745 return os::is_interrupted(thread, clear_interrupted);
746 }
747
748
749 // GC Support
750 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
751 jint thread_parity = _oops_do_parity;
752 if (thread_parity != strong_roots_parity) {
753 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
754 if (res == thread_parity) {
755 return true;
756 } else {
757 guarantee(res == strong_roots_parity, "Or else what?");
758 assert(SharedHeap::heap()->workers()->active_workers() > 0,
759 "Should only fail when parallel.");
760 return false;
761 }
762 }
763 assert(SharedHeap::heap()->workers()->active_workers() > 0,
764 "Should only fail when parallel.");
765 return false;
766 }
767
768 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
769 active_handles()->oops_do(f);
770 // Do oop for ThreadShadow
771 f->do_oop((oop*)&_pending_exception);
772 handle_area()->oops_do(f);
773 }
774
775 void Thread::nmethods_do(CodeBlobClosure* cf) {
776 // no nmethods in a generic thread...
777 }
778
779 void Thread::metadata_do(void f(Metadata*)) {
780 if (metadata_handles() != NULL) {
781 for (int i = 0; i< metadata_handles()->length(); i++) {
782 f(metadata_handles()->at(i));
783 }
784 }
785 }
786
787 void Thread::print_on(outputStream* st) const {
788 // get_priority assumes osthread initialized
789 if (osthread() != NULL) {
790 int os_prio;
791 if (os::get_native_priority(this, &os_prio) == OS_OK) {
792 st->print("os_prio=%d ", os_prio);
793 }
794 st->print("tid=" INTPTR_FORMAT " ", this);
795 ext().print_on(st);
796 osthread()->print_on(st);
797 }
798 debug_only(if (WizardMode) print_owned_locks_on(st);)
799 }
800
801 // Thread::print_on_error() is called by fatal error handler. Don't use
802 // any lock or allocate memory.
803 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
804 if (is_VM_thread()) st->print("VMThread");
805 else if (is_Compiler_thread()) st->print("CompilerThread");
806 else if (is_Java_thread()) st->print("JavaThread");
807 else if (is_GC_task_thread()) st->print("GCTaskThread");
808 else if (is_Watcher_thread()) st->print("WatcherThread");
809 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
810 else st->print("Thread");
811
812 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
813 _stack_base - _stack_size, _stack_base);
814
815 if (osthread()) {
816 st->print(" [id=%d]", osthread()->thread_id());
817 }
818 }
819
820 #ifdef ASSERT
821 void Thread::print_owned_locks_on(outputStream* st) const {
822 Monitor *cur = _owned_locks;
823 if (cur == NULL) {
824 st->print(" (no locks) ");
825 } else {
826 st->print_cr(" Locks owned:");
827 while (cur) {
828 cur->print_on(st);
829 cur = cur->next();
830 }
831 }
832 }
833
834 static int ref_use_count = 0;
835
836 bool Thread::owns_locks_but_compiled_lock() const {
837 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
838 if (cur != Compile_lock) return true;
839 }
840 return false;
841 }
842
843
844 #endif
845
846 #ifndef PRODUCT
847
848 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
849 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
850 // no threads which allow_vm_block's are held
851 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
852 // Check if current thread is allowed to block at a safepoint
853 if (!(_allow_safepoint_count == 0)) {
854 fatal("Possible safepoint reached by thread that does not allow it");
855 }
856 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
857 fatal("LEAF method calling lock?");
858 }
859
860 #ifdef ASSERT
861 if (potential_vm_operation && is_Java_thread()
862 && !Universe::is_bootstrapping()) {
863 // Make sure we do not hold any locks that the VM thread also uses.
864 // This could potentially lead to deadlocks
865 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
866 // Threads_lock is special, since the safepoint synchronization will not start before this is
867 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
868 // since it is used to transfer control between JavaThreads and the VMThread
869 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
870 if ((cur->allow_vm_block() &&
871 cur != Threads_lock &&
872 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
873 cur != VMOperationRequest_lock &&
874 cur != VMOperationQueue_lock) ||
875 cur->rank() == Mutex::special) {
876 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
877 }
878 }
879 }
880
881 if (GCALotAtAllSafepoints) {
882 // We could enter a safepoint here and thus have a gc
883 InterfaceSupport::check_gc_alot();
884 }
885 #endif
886 }
887 #endif
888
889 bool Thread::is_in_stack(address adr) const {
890 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
891 address end = os::current_stack_pointer();
892 // Allow non Java threads to call this without stack_base
893 if (_stack_base == NULL) return true;
894 if (stack_base() >= adr && adr >= end) return true;
895
896 return false;
897 }
898
899
900 bool Thread::is_in_usable_stack(address adr) const {
901 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
902 size_t usable_stack_size = _stack_size - stack_guard_size;
903
904 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
905 }
906
907
908 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
909 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
910 // used for compilation in the future. If that change is made, the need for these methods
911 // should be revisited, and they should be removed if possible.
912
913 bool Thread::is_lock_owned(address adr) const {
914 return on_local_stack(adr);
915 }
916
917 bool Thread::set_as_starting_thread() {
918 // NOTE: this must be called inside the main thread.
919 return os::create_main_thread((JavaThread*)this);
920 }
921
922 static void initialize_class(Symbol* class_name, TRAPS) {
923 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
924 InstanceKlass::cast(klass)->initialize(CHECK);
925 }
926
927
928 // Creates the initial ThreadGroup
929 static Handle create_initial_thread_group(TRAPS) {
930 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
931 instanceKlassHandle klass (THREAD, k);
932
933 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
934 {
935 JavaValue result(T_VOID);
936 JavaCalls::call_special(&result,
937 system_instance,
938 klass,
939 vmSymbols::object_initializer_name(),
940 vmSymbols::void_method_signature(),
941 CHECK_NH);
942 }
943 Universe::set_system_thread_group(system_instance());
944
945 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
946 {
947 JavaValue result(T_VOID);
948 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
949 JavaCalls::call_special(&result,
950 main_instance,
951 klass,
952 vmSymbols::object_initializer_name(),
953 vmSymbols::threadgroup_string_void_signature(),
954 system_instance,
955 string,
956 CHECK_NH);
957 }
958 return main_instance;
959 }
960
961 // Creates the initial Thread
962 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
963 TRAPS) {
964 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
965 instanceKlassHandle klass (THREAD, k);
966 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
967
968 java_lang_Thread::set_thread(thread_oop(), thread);
969 java_lang_Thread::set_priority(thread_oop(), NormPriority);
970 thread->set_threadObj(thread_oop());
971
972 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
973
974 JavaValue result(T_VOID);
975 JavaCalls::call_special(&result, thread_oop,
976 klass,
977 vmSymbols::object_initializer_name(),
978 vmSymbols::threadgroup_string_void_signature(),
979 thread_group,
980 string,
981 CHECK_NULL);
982 return thread_oop();
983 }
984
985 static void call_initializeSystemClass(TRAPS) {
986 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
987 instanceKlassHandle klass (THREAD, k);
988
989 JavaValue result(T_VOID);
990 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
991 vmSymbols::void_method_signature(), CHECK);
992 }
993
994 char java_runtime_name[128] = "";
995 char java_runtime_version[128] = "";
996
997 // extract the JRE name from sun.misc.Version.java_runtime_name
998 static const char* get_java_runtime_name(TRAPS) {
999 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1000 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1001 fieldDescriptor fd;
1002 bool found = k != NULL &&
1003 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1004 vmSymbols::string_signature(), &fd);
1005 if (found) {
1006 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1007 if (name_oop == NULL) {
1008 return NULL;
1009 }
1010 const char* name = java_lang_String::as_utf8_string(name_oop,
1011 java_runtime_name,
1012 sizeof(java_runtime_name));
1013 return name;
1014 } else {
1015 return NULL;
1016 }
1017 }
1018
1019 // extract the JRE version from sun.misc.Version.java_runtime_version
1020 static const char* get_java_runtime_version(TRAPS) {
1021 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1022 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1023 fieldDescriptor fd;
1024 bool found = k != NULL &&
1025 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1026 vmSymbols::string_signature(), &fd);
1027 if (found) {
1028 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1029 if (name_oop == NULL) {
1030 return NULL;
1031 }
1032 const char* name = java_lang_String::as_utf8_string(name_oop,
1033 java_runtime_version,
1034 sizeof(java_runtime_version));
1035 return name;
1036 } else {
1037 return NULL;
1038 }
1039 }
1040
1041 // General purpose hook into Java code, run once when the VM is initialized.
1042 // The Java library method itself may be changed independently from the VM.
1043 static void call_postVMInitHook(TRAPS) {
1044 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1045 instanceKlassHandle klass (THREAD, k);
1046 if (klass.not_null()) {
1047 JavaValue result(T_VOID);
1048 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1049 vmSymbols::void_method_signature(),
1050 CHECK);
1051 }
1052 }
1053
1054 static void reset_vm_info_property(TRAPS) {
1055 // the vm info string
1056 ResourceMark rm(THREAD);
1057 const char *vm_info = VM_Version::vm_info_string();
1058
1059 // java.lang.System class
1060 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1061 instanceKlassHandle klass (THREAD, k);
1062
1063 // setProperty arguments
1064 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1065 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1066
1067 // return value
1068 JavaValue r(T_OBJECT);
1069
1070 // public static String setProperty(String key, String value);
1071 JavaCalls::call_static(&r,
1072 klass,
1073 vmSymbols::setProperty_name(),
1074 vmSymbols::string_string_string_signature(),
1075 key_str,
1076 value_str,
1077 CHECK);
1078 }
1079
1080
1081 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1082 bool daemon, TRAPS) {
1083 assert(thread_group.not_null(), "thread group should be specified");
1084 assert(threadObj() == NULL, "should only create Java thread object once");
1085
1086 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1087 instanceKlassHandle klass (THREAD, k);
1088 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1089
1090 java_lang_Thread::set_thread(thread_oop(), this);
1091 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1092 set_threadObj(thread_oop());
1093
1094 JavaValue result(T_VOID);
1095 if (thread_name != NULL) {
1096 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1097 // Thread gets assigned specified name and null target
1098 JavaCalls::call_special(&result,
1099 thread_oop,
1100 klass,
1101 vmSymbols::object_initializer_name(),
1102 vmSymbols::threadgroup_string_void_signature(),
1103 thread_group, // Argument 1
1104 name, // Argument 2
1105 THREAD);
1106 } else {
1107 // Thread gets assigned name "Thread-nnn" and null target
1108 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1109 JavaCalls::call_special(&result,
1110 thread_oop,
1111 klass,
1112 vmSymbols::object_initializer_name(),
1113 vmSymbols::threadgroup_runnable_void_signature(),
1114 thread_group, // Argument 1
1115 Handle(), // Argument 2
1116 THREAD);
1117 }
1118
1119
1120 if (daemon) {
1121 java_lang_Thread::set_daemon(thread_oop());
1122 }
1123
1124 if (HAS_PENDING_EXCEPTION) {
1125 return;
1126 }
1127
1128 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1129 Handle threadObj(THREAD, this->threadObj());
1130
1131 JavaCalls::call_special(&result,
1132 thread_group,
1133 group,
1134 vmSymbols::add_method_name(),
1135 vmSymbols::thread_void_signature(),
1136 threadObj, // Arg 1
1137 THREAD);
1138 }
1139
1140 // NamedThread -- non-JavaThread subclasses with multiple
1141 // uniquely named instances should derive from this.
1142 NamedThread::NamedThread() : Thread() {
1143 _name = NULL;
1144 _processed_thread = NULL;
1145 }
1146
1147 NamedThread::~NamedThread() {
1148 if (_name != NULL) {
1149 FREE_C_HEAP_ARRAY(char, _name);
1150 _name = NULL;
1151 }
1152 }
1153
1154 void NamedThread::set_name(const char* format, ...) {
1155 guarantee(_name == NULL, "Only get to set name once.");
1156 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1157 guarantee(_name != NULL, "alloc failure");
1158 va_list ap;
1159 va_start(ap, format);
1160 jio_vsnprintf(_name, max_name_len, format, ap);
1161 va_end(ap);
1162 }
1163
1164 void NamedThread::print_on(outputStream* st) const {
1165 st->print("\"%s\" ", name());
1166 Thread::print_on(st);
1167 st->cr();
1168 }
1169
1170
1171 // ======= WatcherThread ========
1172
1173 // The watcher thread exists to simulate timer interrupts. It should
1174 // be replaced by an abstraction over whatever native support for
1175 // timer interrupts exists on the platform.
1176
1177 WatcherThread* WatcherThread::_watcher_thread = NULL;
1178 bool WatcherThread::_startable = false;
1179 volatile bool WatcherThread::_should_terminate = false;
1180
1181 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1182 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1183 if (os::create_thread(this, os::watcher_thread)) {
1184 _watcher_thread = this;
1185
1186 // Set the watcher thread to the highest OS priority which should not be
1187 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1188 // is created. The only normal thread using this priority is the reference
1189 // handler thread, which runs for very short intervals only.
1190 // If the VMThread's priority is not lower than the WatcherThread profiling
1191 // will be inaccurate.
1192 os::set_priority(this, MaxPriority);
1193 if (!DisableStartThread) {
1194 os::start_thread(this);
1195 }
1196 }
1197 }
1198
1199 int WatcherThread::sleep() const {
1200 // The WatcherThread is not a JavaThread so we do not honor the
1201 // safepoint protocol for the PeriodicTask_lock.
1202 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1203
1204 if (_should_terminate) {
1205 // check for termination before we do any housekeeping or wait
1206 return 0; // we did not sleep.
1207 }
1208
1209 // remaining will be zero if there are no tasks,
1210 // causing the WatcherThread to sleep until a task is
1211 // enrolled
1212 int remaining = PeriodicTask::time_to_wait();
1213 int time_slept = 0;
1214
1215 // we expect this to timeout - we only ever get unparked when
1216 // we should terminate or when a new task has been enrolled
1217 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1218
1219 jlong time_before_loop = os::javaTimeNanos();
1220
1221 while (true) {
1222 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1223 remaining);
1224 jlong now = os::javaTimeNanos();
1225
1226 if (remaining == 0) {
1227 // if we didn't have any tasks we could have waited for a long time
1228 // consider the time_slept zero and reset time_before_loop
1229 time_slept = 0;
1230 time_before_loop = now;
1231 } else {
1232 // need to recalculate since we might have new tasks in _tasks
1233 time_slept = (int) ((now - time_before_loop) / 1000000);
1234 }
1235
1236 // Change to task list or spurious wakeup of some kind
1237 if (timedout || _should_terminate) {
1238 break;
1239 }
1240
1241 remaining = PeriodicTask::time_to_wait();
1242 if (remaining == 0) {
1243 // Last task was just disenrolled so loop around and wait until
1244 // another task gets enrolled
1245 continue;
1246 }
1247
1248 remaining -= time_slept;
1249 if (remaining <= 0) {
1250 break;
1251 }
1252 }
1253
1254 return time_slept;
1255 }
1256
1257 void WatcherThread::run() {
1258 assert(this == watcher_thread(), "just checking");
1259
1260 this->record_stack_base_and_size();
1261 this->initialize_thread_local_storage();
1262 this->set_native_thread_name(this->name());
1263 this->set_active_handles(JNIHandleBlock::allocate_block());
1264 while (true) {
1265 assert(watcher_thread() == Thread::current(), "thread consistency check");
1266 assert(watcher_thread() == this, "thread consistency check");
1267
1268 // Calculate how long it'll be until the next PeriodicTask work
1269 // should be done, and sleep that amount of time.
1270 int time_waited = sleep();
1271
1272 if (is_error_reported()) {
1273 // A fatal error has happened, the error handler(VMError::report_and_die)
1274 // should abort JVM after creating an error log file. However in some
1275 // rare cases, the error handler itself might deadlock. Here we try to
1276 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1277 //
1278 // This code is in WatcherThread because WatcherThread wakes up
1279 // periodically so the fatal error handler doesn't need to do anything;
1280 // also because the WatcherThread is less likely to crash than other
1281 // threads.
1282
1283 for (;;) {
1284 if (!ShowMessageBoxOnError
1285 && (OnError == NULL || OnError[0] == '\0')
1286 && Arguments::abort_hook() == NULL) {
1287 os::sleep(this, 2 * 60 * 1000, false);
1288 fdStream err(defaultStream::output_fd());
1289 err.print_raw_cr("# [ timer expired, abort... ]");
1290 // skip atexit/vm_exit/vm_abort hooks
1291 os::die();
1292 }
1293
1294 // Wake up 5 seconds later, the fatal handler may reset OnError or
1295 // ShowMessageBoxOnError when it is ready to abort.
1296 os::sleep(this, 5 * 1000, false);
1297 }
1298 }
1299
1300 if (_should_terminate) {
1301 // check for termination before posting the next tick
1302 break;
1303 }
1304
1305 PeriodicTask::real_time_tick(time_waited);
1306 }
1307
1308 // Signal that it is terminated
1309 {
1310 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1311 _watcher_thread = NULL;
1312 Terminator_lock->notify();
1313 }
1314
1315 // Thread destructor usually does this..
1316 ThreadLocalStorage::set_thread(NULL);
1317 }
1318
1319 void WatcherThread::start() {
1320 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1321
1322 if (watcher_thread() == NULL && _startable) {
1323 _should_terminate = false;
1324 // Create the single instance of WatcherThread
1325 new WatcherThread();
1326 }
1327 }
1328
1329 void WatcherThread::make_startable() {
1330 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1331 _startable = true;
1332 }
1333
1334 void WatcherThread::stop() {
1335 {
1336 // Follow normal safepoint aware lock enter protocol since the
1337 // WatcherThread is stopped by another JavaThread.
1338 MutexLocker ml(PeriodicTask_lock);
1339 _should_terminate = true;
1340
1341 WatcherThread* watcher = watcher_thread();
1342 if (watcher != NULL) {
1343 // unpark the WatcherThread so it can see that it should terminate
1344 watcher->unpark();
1345 }
1346 }
1347
1348 MutexLocker mu(Terminator_lock);
1349
1350 while (watcher_thread() != NULL) {
1351 // This wait should make safepoint checks, wait without a timeout,
1352 // and wait as a suspend-equivalent condition.
1353 //
1354 // Note: If the FlatProfiler is running, then this thread is waiting
1355 // for the WatcherThread to terminate and the WatcherThread, via the
1356 // FlatProfiler task, is waiting for the external suspend request on
1357 // this thread to complete. wait_for_ext_suspend_completion() will
1358 // eventually timeout, but that takes time. Making this wait a
1359 // suspend-equivalent condition solves that timeout problem.
1360 //
1361 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1362 Mutex::_as_suspend_equivalent_flag);
1363 }
1364 }
1365
1366 void WatcherThread::unpark() {
1367 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1368 PeriodicTask_lock->notify();
1369 }
1370
1371 void WatcherThread::print_on(outputStream* st) const {
1372 st->print("\"%s\" ", name());
1373 Thread::print_on(st);
1374 st->cr();
1375 }
1376
1377 // ======= JavaThread ========
1378
1379 // A JavaThread is a normal Java thread
1380
1381 void JavaThread::initialize() {
1382 // Initialize fields
1383
1384 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1385 set_claimed_par_id(UINT_MAX);
1386
1387 set_saved_exception_pc(NULL);
1388 set_threadObj(NULL);
1389 _anchor.clear();
1390 set_entry_point(NULL);
1391 set_jni_functions(jni_functions());
1392 set_callee_target(NULL);
1393 set_vm_result(NULL);
1394 set_vm_result_2(NULL);
1395 set_vframe_array_head(NULL);
1396 set_vframe_array_last(NULL);
1397 set_deferred_locals(NULL);
1398 set_deopt_mark(NULL);
1399 set_deopt_nmethod(NULL);
1400 clear_must_deopt_id();
1401 set_monitor_chunks(NULL);
1402 set_next(NULL);
1403 set_thread_state(_thread_new);
1404 _terminated = _not_terminated;
1405 _privileged_stack_top = NULL;
1406 _array_for_gc = NULL;
1407 _suspend_equivalent = false;
1408 _in_deopt_handler = 0;
1409 _doing_unsafe_access = false;
1410 _stack_guard_state = stack_guard_unused;
1411 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1412 _exception_pc = 0;
1413 _exception_handler_pc = 0;
1414 _is_method_handle_return = 0;
1415 _jvmti_thread_state= NULL;
1416 _should_post_on_exceptions_flag = JNI_FALSE;
1417 _jvmti_get_loaded_classes_closure = NULL;
1418 _interp_only_mode = 0;
1419 _special_runtime_exit_condition = _no_async_condition;
1420 _pending_async_exception = NULL;
1421 _thread_stat = NULL;
1422 _thread_stat = new ThreadStatistics();
1423 _blocked_on_compilation = false;
1424 _jni_active_critical = 0;
1425 _pending_jni_exception_check_fn = NULL;
1426 _do_not_unlock_if_synchronized = false;
1427 _cached_monitor_info = NULL;
1428 _parker = Parker::Allocate(this);
1429
1430 #ifndef PRODUCT
1431 _jmp_ring_index = 0;
1432 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1433 record_jump(NULL, NULL, NULL, 0);
1434 }
1435 #endif // PRODUCT
1436
1437 set_thread_profiler(NULL);
1438 if (FlatProfiler::is_active()) {
1439 // This is where we would decide to either give each thread it's own profiler
1440 // or use one global one from FlatProfiler,
1441 // or up to some count of the number of profiled threads, etc.
1442 ThreadProfiler* pp = new ThreadProfiler();
1443 pp->engage();
1444 set_thread_profiler(pp);
1445 }
1446
1447 // Setup safepoint state info for this thread
1448 ThreadSafepointState::create(this);
1449
1450 debug_only(_java_call_counter = 0);
1451
1452 // JVMTI PopFrame support
1453 _popframe_condition = popframe_inactive;
1454 _popframe_preserved_args = NULL;
1455 _popframe_preserved_args_size = 0;
1456 _frames_to_pop_failed_realloc = 0;
1457
1458 pd_initialize();
1459 }
1460
1461 #if INCLUDE_ALL_GCS
1462 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1463 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1464 #endif // INCLUDE_ALL_GCS
1465
1466 JavaThread::JavaThread(bool is_attaching_via_jni) :
1467 Thread()
1468 #if INCLUDE_ALL_GCS
1469 , _satb_mark_queue(&_satb_mark_queue_set),
1470 _dirty_card_queue(&_dirty_card_queue_set)
1471 #endif // INCLUDE_ALL_GCS
1472 {
1473 initialize();
1474 if (is_attaching_via_jni) {
1475 _jni_attach_state = _attaching_via_jni;
1476 } else {
1477 _jni_attach_state = _not_attaching_via_jni;
1478 }
1479 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1480 }
1481
1482 bool JavaThread::reguard_stack(address cur_sp) {
1483 if (_stack_guard_state != stack_guard_yellow_disabled) {
1484 return true; // Stack already guarded or guard pages not needed.
1485 }
1486
1487 if (register_stack_overflow()) {
1488 // For those architectures which have separate register and
1489 // memory stacks, we must check the register stack to see if
1490 // it has overflowed.
1491 return false;
1492 }
1493
1494 // Java code never executes within the yellow zone: the latter is only
1495 // there to provoke an exception during stack banging. If java code
1496 // is executing there, either StackShadowPages should be larger, or
1497 // some exception code in c1, c2 or the interpreter isn't unwinding
1498 // when it should.
1499 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1500
1501 enable_stack_yellow_zone();
1502 return true;
1503 }
1504
1505 bool JavaThread::reguard_stack(void) {
1506 return reguard_stack(os::current_stack_pointer());
1507 }
1508
1509
1510 void JavaThread::block_if_vm_exited() {
1511 if (_terminated == _vm_exited) {
1512 // _vm_exited is set at safepoint, and Threads_lock is never released
1513 // we will block here forever
1514 Threads_lock->lock_without_safepoint_check();
1515 ShouldNotReachHere();
1516 }
1517 }
1518
1519
1520 // Remove this ifdef when C1 is ported to the compiler interface.
1521 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1522 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1523
1524 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1525 Thread()
1526 #if INCLUDE_ALL_GCS
1527 , _satb_mark_queue(&_satb_mark_queue_set),
1528 _dirty_card_queue(&_dirty_card_queue_set)
1529 #endif // INCLUDE_ALL_GCS
1530 {
1531 initialize();
1532 _jni_attach_state = _not_attaching_via_jni;
1533 set_entry_point(entry_point);
1534 // Create the native thread itself.
1535 // %note runtime_23
1536 os::ThreadType thr_type = os::java_thread;
1537 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1538 os::java_thread;
1539 os::create_thread(this, thr_type, stack_sz);
1540 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1541 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1542 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1543 // the exception consists of creating the exception object & initializing it, initialization
1544 // will leave the VM via a JavaCall and then all locks must be unlocked).
1545 //
1546 // The thread is still suspended when we reach here. Thread must be explicit started
1547 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1548 // by calling Threads:add. The reason why this is not done here, is because the thread
1549 // object must be fully initialized (take a look at JVM_Start)
1550 }
1551
1552 JavaThread::~JavaThread() {
1553
1554 // JSR166 -- return the parker to the free list
1555 Parker::Release(_parker);
1556 _parker = NULL;
1557
1558 // Free any remaining previous UnrollBlock
1559 vframeArray* old_array = vframe_array_last();
1560
1561 if (old_array != NULL) {
1562 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1563 old_array->set_unroll_block(NULL);
1564 delete old_info;
1565 delete old_array;
1566 }
1567
1568 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1569 if (deferred != NULL) {
1570 // This can only happen if thread is destroyed before deoptimization occurs.
1571 assert(deferred->length() != 0, "empty array!");
1572 do {
1573 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1574 deferred->remove_at(0);
1575 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1576 delete dlv;
1577 } while (deferred->length() != 0);
1578 delete deferred;
1579 }
1580
1581 // All Java related clean up happens in exit
1582 ThreadSafepointState::destroy(this);
1583 if (_thread_profiler != NULL) delete _thread_profiler;
1584 if (_thread_stat != NULL) delete _thread_stat;
1585 }
1586
1587
1588 // The first routine called by a new Java thread
1589 void JavaThread::run() {
1590 // initialize thread-local alloc buffer related fields
1591 this->initialize_tlab();
1592
1593 // used to test validity of stack trace backs
1594 this->record_base_of_stack_pointer();
1595
1596 // Record real stack base and size.
1597 this->record_stack_base_and_size();
1598
1599 // Initialize thread local storage; set before calling MutexLocker
1600 this->initialize_thread_local_storage();
1601
1602 this->create_stack_guard_pages();
1603
1604 this->cache_global_variables();
1605
1606 // Thread is now sufficient initialized to be handled by the safepoint code as being
1607 // in the VM. Change thread state from _thread_new to _thread_in_vm
1608 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1609
1610 assert(JavaThread::current() == this, "sanity check");
1611 assert(!Thread::current()->owns_locks(), "sanity check");
1612
1613 DTRACE_THREAD_PROBE(start, this);
1614
1615 // This operation might block. We call that after all safepoint checks for a new thread has
1616 // been completed.
1617 this->set_active_handles(JNIHandleBlock::allocate_block());
1618
1619 if (JvmtiExport::should_post_thread_life()) {
1620 JvmtiExport::post_thread_start(this);
1621 }
1622
1623 EventThreadStart event;
1624 if (event.should_commit()) {
1625 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1626 event.commit();
1627 }
1628
1629 // We call another function to do the rest so we are sure that the stack addresses used
1630 // from there will be lower than the stack base just computed
1631 thread_main_inner();
1632
1633 // Note, thread is no longer valid at this point!
1634 }
1635
1636
1637 void JavaThread::thread_main_inner() {
1638 assert(JavaThread::current() == this, "sanity check");
1639 assert(this->threadObj() != NULL, "just checking");
1640
1641 // Execute thread entry point unless this thread has a pending exception
1642 // or has been stopped before starting.
1643 // Note: Due to JVM_StopThread we can have pending exceptions already!
1644 if (!this->has_pending_exception() &&
1645 !java_lang_Thread::is_stillborn(this->threadObj())) {
1646 {
1647 ResourceMark rm(this);
1648 this->set_native_thread_name(this->get_thread_name());
1649 }
1650 HandleMark hm(this);
1651 this->entry_point()(this, this);
1652 }
1653
1654 DTRACE_THREAD_PROBE(stop, this);
1655
1656 this->exit(false);
1657 delete this;
1658 }
1659
1660
1661 static void ensure_join(JavaThread* thread) {
1662 // We do not need to grap the Threads_lock, since we are operating on ourself.
1663 Handle threadObj(thread, thread->threadObj());
1664 assert(threadObj.not_null(), "java thread object must exist");
1665 ObjectLocker lock(threadObj, thread);
1666 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1667 thread->clear_pending_exception();
1668 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1669 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1670 // Clear the native thread instance - this makes isAlive return false and allows the join()
1671 // to complete once we've done the notify_all below
1672 java_lang_Thread::set_thread(threadObj(), NULL);
1673 lock.notify_all(thread);
1674 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1675 thread->clear_pending_exception();
1676 }
1677
1678
1679 // For any new cleanup additions, please check to see if they need to be applied to
1680 // cleanup_failed_attach_current_thread as well.
1681 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1682 assert(this == JavaThread::current(), "thread consistency check");
1683
1684 HandleMark hm(this);
1685 Handle uncaught_exception(this, this->pending_exception());
1686 this->clear_pending_exception();
1687 Handle threadObj(this, this->threadObj());
1688 assert(threadObj.not_null(), "Java thread object should be created");
1689
1690 if (get_thread_profiler() != NULL) {
1691 get_thread_profiler()->disengage();
1692 ResourceMark rm;
1693 get_thread_profiler()->print(get_thread_name());
1694 }
1695
1696
1697 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1698 {
1699 EXCEPTION_MARK;
1700
1701 CLEAR_PENDING_EXCEPTION;
1702 }
1703 if (!destroy_vm) {
1704 if (uncaught_exception.not_null()) {
1705 EXCEPTION_MARK;
1706 // Call method Thread.dispatchUncaughtException().
1707 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1708 JavaValue result(T_VOID);
1709 JavaCalls::call_virtual(&result,
1710 threadObj, thread_klass,
1711 vmSymbols::dispatchUncaughtException_name(),
1712 vmSymbols::throwable_void_signature(),
1713 uncaught_exception,
1714 THREAD);
1715 if (HAS_PENDING_EXCEPTION) {
1716 ResourceMark rm(this);
1717 jio_fprintf(defaultStream::error_stream(),
1718 "\nException: %s thrown from the UncaughtExceptionHandler"
1719 " in thread \"%s\"\n",
1720 pending_exception()->klass()->external_name(),
1721 get_thread_name());
1722 CLEAR_PENDING_EXCEPTION;
1723 }
1724 }
1725
1726 // Called before the java thread exit since we want to read info
1727 // from java_lang_Thread object
1728 EventThreadEnd event;
1729 if (event.should_commit()) {
1730 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1731 event.commit();
1732 }
1733
1734 // Call after last event on thread
1735 EVENT_THREAD_EXIT(this);
1736
1737 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1738 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1739 // is deprecated anyhow.
1740 if (!is_Compiler_thread()) {
1741 int count = 3;
1742 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1743 EXCEPTION_MARK;
1744 JavaValue result(T_VOID);
1745 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1746 JavaCalls::call_virtual(&result,
1747 threadObj, thread_klass,
1748 vmSymbols::exit_method_name(),
1749 vmSymbols::void_method_signature(),
1750 THREAD);
1751 CLEAR_PENDING_EXCEPTION;
1752 }
1753 }
1754 // notify JVMTI
1755 if (JvmtiExport::should_post_thread_life()) {
1756 JvmtiExport::post_thread_end(this);
1757 }
1758
1759 // We have notified the agents that we are exiting, before we go on,
1760 // we must check for a pending external suspend request and honor it
1761 // in order to not surprise the thread that made the suspend request.
1762 while (true) {
1763 {
1764 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1765 if (!is_external_suspend()) {
1766 set_terminated(_thread_exiting);
1767 ThreadService::current_thread_exiting(this);
1768 break;
1769 }
1770 // Implied else:
1771 // Things get a little tricky here. We have a pending external
1772 // suspend request, but we are holding the SR_lock so we
1773 // can't just self-suspend. So we temporarily drop the lock
1774 // and then self-suspend.
1775 }
1776
1777 ThreadBlockInVM tbivm(this);
1778 java_suspend_self();
1779
1780 // We're done with this suspend request, but we have to loop around
1781 // and check again. Eventually we will get SR_lock without a pending
1782 // external suspend request and will be able to mark ourselves as
1783 // exiting.
1784 }
1785 // no more external suspends are allowed at this point
1786 } else {
1787 // before_exit() has already posted JVMTI THREAD_END events
1788 }
1789
1790 // Notify waiters on thread object. This has to be done after exit() is called
1791 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1792 // group should have the destroyed bit set before waiters are notified).
1793 ensure_join(this);
1794 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1795
1796 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1797 // held by this thread must be released. A detach operation must only
1798 // get here if there are no Java frames on the stack. Therefore, any
1799 // owned monitors at this point MUST be JNI-acquired monitors which are
1800 // pre-inflated and in the monitor cache.
1801 //
1802 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1803 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1804 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1805 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1806 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1807 }
1808
1809 // These things needs to be done while we are still a Java Thread. Make sure that thread
1810 // is in a consistent state, in case GC happens
1811 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1812
1813 if (active_handles() != NULL) {
1814 JNIHandleBlock* block = active_handles();
1815 set_active_handles(NULL);
1816 JNIHandleBlock::release_block(block);
1817 }
1818
1819 if (free_handle_block() != NULL) {
1820 JNIHandleBlock* block = free_handle_block();
1821 set_free_handle_block(NULL);
1822 JNIHandleBlock::release_block(block);
1823 }
1824
1825 // These have to be removed while this is still a valid thread.
1826 remove_stack_guard_pages();
1827
1828 if (UseTLAB) {
1829 tlab().make_parsable(true); // retire TLAB
1830 }
1831
1832 if (JvmtiEnv::environments_might_exist()) {
1833 JvmtiExport::cleanup_thread(this);
1834 }
1835
1836 // We must flush any deferred card marks before removing a thread from
1837 // the list of active threads.
1838 Universe::heap()->flush_deferred_store_barrier(this);
1839 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1840
1841 #if INCLUDE_ALL_GCS
1842 // We must flush the G1-related buffers before removing a thread
1843 // from the list of active threads. We must do this after any deferred
1844 // card marks have been flushed (above) so that any entries that are
1845 // added to the thread's dirty card queue as a result are not lost.
1846 if (UseG1GC) {
1847 flush_barrier_queues();
1848 }
1849 #endif // INCLUDE_ALL_GCS
1850
1851 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1852 Threads::remove(this);
1853 }
1854
1855 #if INCLUDE_ALL_GCS
1856 // Flush G1-related queues.
1857 void JavaThread::flush_barrier_queues() {
1858 satb_mark_queue().flush();
1859 dirty_card_queue().flush();
1860 }
1861
1862 void JavaThread::initialize_queues() {
1863 assert(!SafepointSynchronize::is_at_safepoint(),
1864 "we should not be at a safepoint");
1865
1866 ObjPtrQueue& satb_queue = satb_mark_queue();
1867 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1868 // The SATB queue should have been constructed with its active
1869 // field set to false.
1870 assert(!satb_queue.is_active(), "SATB queue should not be active");
1871 assert(satb_queue.is_empty(), "SATB queue should be empty");
1872 // If we are creating the thread during a marking cycle, we should
1873 // set the active field of the SATB queue to true.
1874 if (satb_queue_set.is_active()) {
1875 satb_queue.set_active(true);
1876 }
1877
1878 DirtyCardQueue& dirty_queue = dirty_card_queue();
1879 // The dirty card queue should have been constructed with its
1880 // active field set to true.
1881 assert(dirty_queue.is_active(), "dirty card queue should be active");
1882 }
1883 #endif // INCLUDE_ALL_GCS
1884
1885 void JavaThread::cleanup_failed_attach_current_thread() {
1886 if (get_thread_profiler() != NULL) {
1887 get_thread_profiler()->disengage();
1888 ResourceMark rm;
1889 get_thread_profiler()->print(get_thread_name());
1890 }
1891
1892 if (active_handles() != NULL) {
1893 JNIHandleBlock* block = active_handles();
1894 set_active_handles(NULL);
1895 JNIHandleBlock::release_block(block);
1896 }
1897
1898 if (free_handle_block() != NULL) {
1899 JNIHandleBlock* block = free_handle_block();
1900 set_free_handle_block(NULL);
1901 JNIHandleBlock::release_block(block);
1902 }
1903
1904 // These have to be removed while this is still a valid thread.
1905 remove_stack_guard_pages();
1906
1907 if (UseTLAB) {
1908 tlab().make_parsable(true); // retire TLAB, if any
1909 }
1910
1911 #if INCLUDE_ALL_GCS
1912 if (UseG1GC) {
1913 flush_barrier_queues();
1914 }
1915 #endif // INCLUDE_ALL_GCS
1916
1917 Threads::remove(this);
1918 delete this;
1919 }
1920
1921
1922
1923
1924 JavaThread* JavaThread::active() {
1925 Thread* thread = ThreadLocalStorage::thread();
1926 assert(thread != NULL, "just checking");
1927 if (thread->is_Java_thread()) {
1928 return (JavaThread*) thread;
1929 } else {
1930 assert(thread->is_VM_thread(), "this must be a vm thread");
1931 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1932 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1933 assert(ret->is_Java_thread(), "must be a Java thread");
1934 return ret;
1935 }
1936 }
1937
1938 bool JavaThread::is_lock_owned(address adr) const {
1939 if (Thread::is_lock_owned(adr)) return true;
1940
1941 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1942 if (chunk->contains(adr)) return true;
1943 }
1944
1945 return false;
1946 }
1947
1948
1949 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1950 chunk->set_next(monitor_chunks());
1951 set_monitor_chunks(chunk);
1952 }
1953
1954 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1955 guarantee(monitor_chunks() != NULL, "must be non empty");
1956 if (monitor_chunks() == chunk) {
1957 set_monitor_chunks(chunk->next());
1958 } else {
1959 MonitorChunk* prev = monitor_chunks();
1960 while (prev->next() != chunk) prev = prev->next();
1961 prev->set_next(chunk->next());
1962 }
1963 }
1964
1965 // JVM support.
1966
1967 // Note: this function shouldn't block if it's called in
1968 // _thread_in_native_trans state (such as from
1969 // check_special_condition_for_native_trans()).
1970 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1971
1972 if (has_last_Java_frame() && has_async_condition()) {
1973 // If we are at a polling page safepoint (not a poll return)
1974 // then we must defer async exception because live registers
1975 // will be clobbered by the exception path. Poll return is
1976 // ok because the call we a returning from already collides
1977 // with exception handling registers and so there is no issue.
1978 // (The exception handling path kills call result registers but
1979 // this is ok since the exception kills the result anyway).
1980
1981 if (is_at_poll_safepoint()) {
1982 // if the code we are returning to has deoptimized we must defer
1983 // the exception otherwise live registers get clobbered on the
1984 // exception path before deoptimization is able to retrieve them.
1985 //
1986 RegisterMap map(this, false);
1987 frame caller_fr = last_frame().sender(&map);
1988 assert(caller_fr.is_compiled_frame(), "what?");
1989 if (caller_fr.is_deoptimized_frame()) {
1990 if (TraceExceptions) {
1991 ResourceMark rm;
1992 tty->print_cr("deferred async exception at compiled safepoint");
1993 }
1994 return;
1995 }
1996 }
1997 }
1998
1999 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2000 if (condition == _no_async_condition) {
2001 // Conditions have changed since has_special_runtime_exit_condition()
2002 // was called:
2003 // - if we were here only because of an external suspend request,
2004 // then that was taken care of above (or cancelled) so we are done
2005 // - if we were here because of another async request, then it has
2006 // been cleared between the has_special_runtime_exit_condition()
2007 // and now so again we are done
2008 return;
2009 }
2010
2011 // Check for pending async. exception
2012 if (_pending_async_exception != NULL) {
2013 // Only overwrite an already pending exception, if it is not a threadDeath.
2014 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2015
2016 // We cannot call Exceptions::_throw(...) here because we cannot block
2017 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2018
2019 if (TraceExceptions) {
2020 ResourceMark rm;
2021 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2022 if (has_last_Java_frame()) {
2023 frame f = last_frame();
2024 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2025 }
2026 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2027 }
2028 _pending_async_exception = NULL;
2029 clear_has_async_exception();
2030 }
2031 }
2032
2033 if (check_unsafe_error &&
2034 condition == _async_unsafe_access_error && !has_pending_exception()) {
2035 condition = _no_async_condition; // done
2036 switch (thread_state()) {
2037 case _thread_in_vm: {
2038 JavaThread* THREAD = this;
2039 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2040 }
2041 case _thread_in_native: {
2042 ThreadInVMfromNative tiv(this);
2043 JavaThread* THREAD = this;
2044 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2045 }
2046 case _thread_in_Java: {
2047 ThreadInVMfromJava tiv(this);
2048 JavaThread* THREAD = this;
2049 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2050 }
2051 default:
2052 ShouldNotReachHere();
2053 }
2054 }
2055
2056 assert(condition == _no_async_condition || has_pending_exception() ||
2057 (!check_unsafe_error && condition == _async_unsafe_access_error),
2058 "must have handled the async condition, if no exception");
2059 }
2060
2061 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2062 //
2063 // Check for pending external suspend. Internal suspend requests do
2064 // not use handle_special_runtime_exit_condition().
2065 // If JNIEnv proxies are allowed, don't self-suspend if the target
2066 // thread is not the current thread. In older versions of jdbx, jdbx
2067 // threads could call into the VM with another thread's JNIEnv so we
2068 // can be here operating on behalf of a suspended thread (4432884).
2069 bool do_self_suspend = is_external_suspend_with_lock();
2070 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2071 //
2072 // Because thread is external suspended the safepoint code will count
2073 // thread as at a safepoint. This can be odd because we can be here
2074 // as _thread_in_Java which would normally transition to _thread_blocked
2075 // at a safepoint. We would like to mark the thread as _thread_blocked
2076 // before calling java_suspend_self like all other callers of it but
2077 // we must then observe proper safepoint protocol. (We can't leave
2078 // _thread_blocked with a safepoint in progress). However we can be
2079 // here as _thread_in_native_trans so we can't use a normal transition
2080 // constructor/destructor pair because they assert on that type of
2081 // transition. We could do something like:
2082 //
2083 // JavaThreadState state = thread_state();
2084 // set_thread_state(_thread_in_vm);
2085 // {
2086 // ThreadBlockInVM tbivm(this);
2087 // java_suspend_self()
2088 // }
2089 // set_thread_state(_thread_in_vm_trans);
2090 // if (safepoint) block;
2091 // set_thread_state(state);
2092 //
2093 // but that is pretty messy. Instead we just go with the way the
2094 // code has worked before and note that this is the only path to
2095 // java_suspend_self that doesn't put the thread in _thread_blocked
2096 // mode.
2097
2098 frame_anchor()->make_walkable(this);
2099 java_suspend_self();
2100
2101 // We might be here for reasons in addition to the self-suspend request
2102 // so check for other async requests.
2103 }
2104
2105 if (check_asyncs) {
2106 check_and_handle_async_exceptions();
2107 }
2108 }
2109
2110 void JavaThread::send_thread_stop(oop java_throwable) {
2111 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2112 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2113 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2114
2115 // Do not throw asynchronous exceptions against the compiler thread
2116 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2117 if (is_Compiler_thread()) return;
2118
2119 {
2120 // Actually throw the Throwable against the target Thread - however
2121 // only if there is no thread death exception installed already.
2122 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2123 // If the topmost frame is a runtime stub, then we are calling into
2124 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2125 // must deoptimize the caller before continuing, as the compiled exception handler table
2126 // may not be valid
2127 if (has_last_Java_frame()) {
2128 frame f = last_frame();
2129 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2130 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2131 RegisterMap reg_map(this, UseBiasedLocking);
2132 frame compiled_frame = f.sender(®_map);
2133 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2134 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2135 }
2136 }
2137 }
2138
2139 // Set async. pending exception in thread.
2140 set_pending_async_exception(java_throwable);
2141
2142 if (TraceExceptions) {
2143 ResourceMark rm;
2144 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2145 }
2146 // for AbortVMOnException flag
2147 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2148 }
2149 }
2150
2151
2152 // Interrupt thread so it will wake up from a potential wait()
2153 Thread::interrupt(this);
2154 }
2155
2156 // External suspension mechanism.
2157 //
2158 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2159 // to any VM_locks and it is at a transition
2160 // Self-suspension will happen on the transition out of the vm.
2161 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2162 //
2163 // Guarantees on return:
2164 // + Target thread will not execute any new bytecode (that's why we need to
2165 // force a safepoint)
2166 // + Target thread will not enter any new monitors
2167 //
2168 void JavaThread::java_suspend() {
2169 { MutexLocker mu(Threads_lock);
2170 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2171 return;
2172 }
2173 }
2174
2175 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2176 if (!is_external_suspend()) {
2177 // a racing resume has cancelled us; bail out now
2178 return;
2179 }
2180
2181 // suspend is done
2182 uint32_t debug_bits = 0;
2183 // Warning: is_ext_suspend_completed() may temporarily drop the
2184 // SR_lock to allow the thread to reach a stable thread state if
2185 // it is currently in a transient thread state.
2186 if (is_ext_suspend_completed(false /* !called_by_wait */,
2187 SuspendRetryDelay, &debug_bits)) {
2188 return;
2189 }
2190 }
2191
2192 VM_ForceSafepoint vm_suspend;
2193 VMThread::execute(&vm_suspend);
2194 }
2195
2196 // Part II of external suspension.
2197 // A JavaThread self suspends when it detects a pending external suspend
2198 // request. This is usually on transitions. It is also done in places
2199 // where continuing to the next transition would surprise the caller,
2200 // e.g., monitor entry.
2201 //
2202 // Returns the number of times that the thread self-suspended.
2203 //
2204 // Note: DO NOT call java_suspend_self() when you just want to block current
2205 // thread. java_suspend_self() is the second stage of cooperative
2206 // suspension for external suspend requests and should only be used
2207 // to complete an external suspend request.
2208 //
2209 int JavaThread::java_suspend_self() {
2210 int ret = 0;
2211
2212 // we are in the process of exiting so don't suspend
2213 if (is_exiting()) {
2214 clear_external_suspend();
2215 return ret;
2216 }
2217
2218 assert(_anchor.walkable() ||
2219 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2220 "must have walkable stack");
2221
2222 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2223
2224 assert(!this->is_ext_suspended(),
2225 "a thread trying to self-suspend should not already be suspended");
2226
2227 if (this->is_suspend_equivalent()) {
2228 // If we are self-suspending as a result of the lifting of a
2229 // suspend equivalent condition, then the suspend_equivalent
2230 // flag is not cleared until we set the ext_suspended flag so
2231 // that wait_for_ext_suspend_completion() returns consistent
2232 // results.
2233 this->clear_suspend_equivalent();
2234 }
2235
2236 // A racing resume may have cancelled us before we grabbed SR_lock
2237 // above. Or another external suspend request could be waiting for us
2238 // by the time we return from SR_lock()->wait(). The thread
2239 // that requested the suspension may already be trying to walk our
2240 // stack and if we return now, we can change the stack out from under
2241 // it. This would be a "bad thing (TM)" and cause the stack walker
2242 // to crash. We stay self-suspended until there are no more pending
2243 // external suspend requests.
2244 while (is_external_suspend()) {
2245 ret++;
2246 this->set_ext_suspended();
2247
2248 // _ext_suspended flag is cleared by java_resume()
2249 while (is_ext_suspended()) {
2250 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2251 }
2252 }
2253
2254 return ret;
2255 }
2256
2257 #ifdef ASSERT
2258 // verify the JavaThread has not yet been published in the Threads::list, and
2259 // hence doesn't need protection from concurrent access at this stage
2260 void JavaThread::verify_not_published() {
2261 if (!Threads_lock->owned_by_self()) {
2262 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2263 assert(!Threads::includes(this),
2264 "java thread shouldn't have been published yet!");
2265 } else {
2266 assert(!Threads::includes(this),
2267 "java thread shouldn't have been published yet!");
2268 }
2269 }
2270 #endif
2271
2272 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2273 // progress or when _suspend_flags is non-zero.
2274 // Current thread needs to self-suspend if there is a suspend request and/or
2275 // block if a safepoint is in progress.
2276 // Async exception ISN'T checked.
2277 // Note only the ThreadInVMfromNative transition can call this function
2278 // directly and when thread state is _thread_in_native_trans
2279 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2280 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2281
2282 JavaThread *curJT = JavaThread::current();
2283 bool do_self_suspend = thread->is_external_suspend();
2284
2285 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2286
2287 // If JNIEnv proxies are allowed, don't self-suspend if the target
2288 // thread is not the current thread. In older versions of jdbx, jdbx
2289 // threads could call into the VM with another thread's JNIEnv so we
2290 // can be here operating on behalf of a suspended thread (4432884).
2291 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2292 JavaThreadState state = thread->thread_state();
2293
2294 // We mark this thread_blocked state as a suspend-equivalent so
2295 // that a caller to is_ext_suspend_completed() won't be confused.
2296 // The suspend-equivalent state is cleared by java_suspend_self().
2297 thread->set_suspend_equivalent();
2298
2299 // If the safepoint code sees the _thread_in_native_trans state, it will
2300 // wait until the thread changes to other thread state. There is no
2301 // guarantee on how soon we can obtain the SR_lock and complete the
2302 // self-suspend request. It would be a bad idea to let safepoint wait for
2303 // too long. Temporarily change the state to _thread_blocked to
2304 // let the VM thread know that this thread is ready for GC. The problem
2305 // of changing thread state is that safepoint could happen just after
2306 // java_suspend_self() returns after being resumed, and VM thread will
2307 // see the _thread_blocked state. We must check for safepoint
2308 // after restoring the state and make sure we won't leave while a safepoint
2309 // is in progress.
2310 thread->set_thread_state(_thread_blocked);
2311 thread->java_suspend_self();
2312 thread->set_thread_state(state);
2313 // Make sure new state is seen by VM thread
2314 if (os::is_MP()) {
2315 if (UseMembar) {
2316 // Force a fence between the write above and read below
2317 OrderAccess::fence();
2318 } else {
2319 // Must use this rather than serialization page in particular on Windows
2320 InterfaceSupport::serialize_memory(thread);
2321 }
2322 }
2323 }
2324
2325 if (SafepointSynchronize::do_call_back()) {
2326 // If we are safepointing, then block the caller which may not be
2327 // the same as the target thread (see above).
2328 SafepointSynchronize::block(curJT);
2329 }
2330
2331 if (thread->is_deopt_suspend()) {
2332 thread->clear_deopt_suspend();
2333 RegisterMap map(thread, false);
2334 frame f = thread->last_frame();
2335 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2336 f = f.sender(&map);
2337 }
2338 if (f.id() == thread->must_deopt_id()) {
2339 thread->clear_must_deopt_id();
2340 f.deoptimize(thread);
2341 } else {
2342 fatal("missed deoptimization!");
2343 }
2344 }
2345 }
2346
2347 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2348 // progress or when _suspend_flags is non-zero.
2349 // Current thread needs to self-suspend if there is a suspend request and/or
2350 // block if a safepoint is in progress.
2351 // Also check for pending async exception (not including unsafe access error).
2352 // Note only the native==>VM/Java barriers can call this function and when
2353 // thread state is _thread_in_native_trans.
2354 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2355 check_safepoint_and_suspend_for_native_trans(thread);
2356
2357 if (thread->has_async_exception()) {
2358 // We are in _thread_in_native_trans state, don't handle unsafe
2359 // access error since that may block.
2360 thread->check_and_handle_async_exceptions(false);
2361 }
2362 }
2363
2364 // This is a variant of the normal
2365 // check_special_condition_for_native_trans with slightly different
2366 // semantics for use by critical native wrappers. It does all the
2367 // normal checks but also performs the transition back into
2368 // thread_in_Java state. This is required so that critical natives
2369 // can potentially block and perform a GC if they are the last thread
2370 // exiting the GC_locker.
2371 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2372 check_special_condition_for_native_trans(thread);
2373
2374 // Finish the transition
2375 thread->set_thread_state(_thread_in_Java);
2376
2377 if (thread->do_critical_native_unlock()) {
2378 ThreadInVMfromJavaNoAsyncException tiv(thread);
2379 GC_locker::unlock_critical(thread);
2380 thread->clear_critical_native_unlock();
2381 }
2382 }
2383
2384 // We need to guarantee the Threads_lock here, since resumes are not
2385 // allowed during safepoint synchronization
2386 // Can only resume from an external suspension
2387 void JavaThread::java_resume() {
2388 assert_locked_or_safepoint(Threads_lock);
2389
2390 // Sanity check: thread is gone, has started exiting or the thread
2391 // was not externally suspended.
2392 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2393 return;
2394 }
2395
2396 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2397
2398 clear_external_suspend();
2399
2400 if (is_ext_suspended()) {
2401 clear_ext_suspended();
2402 SR_lock()->notify_all();
2403 }
2404 }
2405
2406 void JavaThread::create_stack_guard_pages() {
2407 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2408 address low_addr = stack_base() - stack_size();
2409 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2410
2411 int allocate = os::allocate_stack_guard_pages();
2412 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2413
2414 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2415 warning("Attempt to allocate stack guard pages failed.");
2416 return;
2417 }
2418
2419 if (os::guard_memory((char *) low_addr, len)) {
2420 _stack_guard_state = stack_guard_enabled;
2421 } else {
2422 warning("Attempt to protect stack guard pages failed.");
2423 if (os::uncommit_memory((char *) low_addr, len)) {
2424 warning("Attempt to deallocate stack guard pages failed.");
2425 }
2426 }
2427 }
2428
2429 void JavaThread::remove_stack_guard_pages() {
2430 assert(Thread::current() == this, "from different thread");
2431 if (_stack_guard_state == stack_guard_unused) return;
2432 address low_addr = stack_base() - stack_size();
2433 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2434
2435 if (os::allocate_stack_guard_pages()) {
2436 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2437 _stack_guard_state = stack_guard_unused;
2438 } else {
2439 warning("Attempt to deallocate stack guard pages failed.");
2440 }
2441 } else {
2442 if (_stack_guard_state == stack_guard_unused) return;
2443 if (os::unguard_memory((char *) low_addr, len)) {
2444 _stack_guard_state = stack_guard_unused;
2445 } else {
2446 warning("Attempt to unprotect stack guard pages failed.");
2447 }
2448 }
2449 }
2450
2451 void JavaThread::enable_stack_yellow_zone() {
2452 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2453 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2454
2455 // The base notation is from the stacks point of view, growing downward.
2456 // We need to adjust it to work correctly with guard_memory()
2457 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2458
2459 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2460 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2461
2462 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2463 _stack_guard_state = stack_guard_enabled;
2464 } else {
2465 warning("Attempt to guard stack yellow zone failed.");
2466 }
2467 enable_register_stack_guard();
2468 }
2469
2470 void JavaThread::disable_stack_yellow_zone() {
2471 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2472 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2473
2474 // Simply return if called for a thread that does not use guard pages.
2475 if (_stack_guard_state == stack_guard_unused) return;
2476
2477 // The base notation is from the stacks point of view, growing downward.
2478 // We need to adjust it to work correctly with guard_memory()
2479 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2480
2481 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2482 _stack_guard_state = stack_guard_yellow_disabled;
2483 } else {
2484 warning("Attempt to unguard stack yellow zone failed.");
2485 }
2486 disable_register_stack_guard();
2487 }
2488
2489 void JavaThread::enable_stack_red_zone() {
2490 // The base notation is from the stacks point of view, growing downward.
2491 // We need to adjust it to work correctly with guard_memory()
2492 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2493 address base = stack_red_zone_base() - stack_red_zone_size();
2494
2495 guarantee(base < stack_base(), "Error calculating stack red zone");
2496 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2497
2498 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2499 warning("Attempt to guard stack red zone failed.");
2500 }
2501 }
2502
2503 void JavaThread::disable_stack_red_zone() {
2504 // The base notation is from the stacks point of view, growing downward.
2505 // We need to adjust it to work correctly with guard_memory()
2506 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2507 address base = stack_red_zone_base() - stack_red_zone_size();
2508 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2509 warning("Attempt to unguard stack red zone failed.");
2510 }
2511 }
2512
2513 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2514 // ignore is there is no stack
2515 if (!has_last_Java_frame()) return;
2516 // traverse the stack frames. Starts from top frame.
2517 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2518 frame* fr = fst.current();
2519 f(fr, fst.register_map());
2520 }
2521 }
2522
2523
2524 #ifndef PRODUCT
2525 // Deoptimization
2526 // Function for testing deoptimization
2527 void JavaThread::deoptimize() {
2528 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2529 StackFrameStream fst(this, UseBiasedLocking);
2530 bool deopt = false; // Dump stack only if a deopt actually happens.
2531 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2532 // Iterate over all frames in the thread and deoptimize
2533 for (; !fst.is_done(); fst.next()) {
2534 if (fst.current()->can_be_deoptimized()) {
2535
2536 if (only_at) {
2537 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2538 // consists of comma or carriage return separated numbers so
2539 // search for the current bci in that string.
2540 address pc = fst.current()->pc();
2541 nmethod* nm = (nmethod*) fst.current()->cb();
2542 ScopeDesc* sd = nm->scope_desc_at(pc);
2543 char buffer[8];
2544 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2545 size_t len = strlen(buffer);
2546 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2547 while (found != NULL) {
2548 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2549 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2550 // Check that the bci found is bracketed by terminators.
2551 break;
2552 }
2553 found = strstr(found + 1, buffer);
2554 }
2555 if (!found) {
2556 continue;
2557 }
2558 }
2559
2560 if (DebugDeoptimization && !deopt) {
2561 deopt = true; // One-time only print before deopt
2562 tty->print_cr("[BEFORE Deoptimization]");
2563 trace_frames();
2564 trace_stack();
2565 }
2566 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2567 }
2568 }
2569
2570 if (DebugDeoptimization && deopt) {
2571 tty->print_cr("[AFTER Deoptimization]");
2572 trace_frames();
2573 }
2574 }
2575
2576
2577 // Make zombies
2578 void JavaThread::make_zombies() {
2579 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2580 if (fst.current()->can_be_deoptimized()) {
2581 // it is a Java nmethod
2582 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2583 nm->make_not_entrant();
2584 }
2585 }
2586 }
2587 #endif // PRODUCT
2588
2589
2590 void JavaThread::deoptimized_wrt_marked_nmethods() {
2591 if (!has_last_Java_frame()) return;
2592 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2593 StackFrameStream fst(this, UseBiasedLocking);
2594 for (; !fst.is_done(); fst.next()) {
2595 if (fst.current()->should_be_deoptimized()) {
2596 if (LogCompilation && xtty != NULL) {
2597 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2598 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2599 this->name(), nm != NULL ? nm->compile_id() : -1);
2600 }
2601
2602 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2603 }
2604 }
2605 }
2606
2607
2608 // If the caller is a NamedThread, then remember, in the current scope,
2609 // the given JavaThread in its _processed_thread field.
2610 class RememberProcessedThread: public StackObj {
2611 NamedThread* _cur_thr;
2612 public:
2613 RememberProcessedThread(JavaThread* jthr) {
2614 Thread* thread = Thread::current();
2615 if (thread->is_Named_thread()) {
2616 _cur_thr = (NamedThread *)thread;
2617 _cur_thr->set_processed_thread(jthr);
2618 } else {
2619 _cur_thr = NULL;
2620 }
2621 }
2622
2623 ~RememberProcessedThread() {
2624 if (_cur_thr) {
2625 _cur_thr->set_processed_thread(NULL);
2626 }
2627 }
2628 };
2629
2630 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2631 // Verify that the deferred card marks have been flushed.
2632 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2633
2634 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2635 // since there may be more than one thread using each ThreadProfiler.
2636
2637 // Traverse the GCHandles
2638 Thread::oops_do(f, cld_f, cf);
2639
2640 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2641 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2642
2643 if (has_last_Java_frame()) {
2644 // Record JavaThread to GC thread
2645 RememberProcessedThread rpt(this);
2646
2647 // Traverse the privileged stack
2648 if (_privileged_stack_top != NULL) {
2649 _privileged_stack_top->oops_do(f);
2650 }
2651
2652 // traverse the registered growable array
2653 if (_array_for_gc != NULL) {
2654 for (int index = 0; index < _array_for_gc->length(); index++) {
2655 f->do_oop(_array_for_gc->adr_at(index));
2656 }
2657 }
2658
2659 // Traverse the monitor chunks
2660 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2661 chunk->oops_do(f);
2662 }
2663
2664 // Traverse the execution stack
2665 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2666 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2667 }
2668 }
2669
2670 // callee_target is never live across a gc point so NULL it here should
2671 // it still contain a methdOop.
2672
2673 set_callee_target(NULL);
2674
2675 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2676 // If we have deferred set_locals there might be oops waiting to be
2677 // written
2678 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2679 if (list != NULL) {
2680 for (int i = 0; i < list->length(); i++) {
2681 list->at(i)->oops_do(f);
2682 }
2683 }
2684
2685 // Traverse instance variables at the end since the GC may be moving things
2686 // around using this function
2687 f->do_oop((oop*) &_threadObj);
2688 f->do_oop((oop*) &_vm_result);
2689 f->do_oop((oop*) &_exception_oop);
2690 f->do_oop((oop*) &_pending_async_exception);
2691
2692 if (jvmti_thread_state() != NULL) {
2693 jvmti_thread_state()->oops_do(f);
2694 }
2695 }
2696
2697 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2698 Thread::nmethods_do(cf); // (super method is a no-op)
2699
2700 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2701 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2702
2703 if (has_last_Java_frame()) {
2704 // Traverse the execution stack
2705 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2706 fst.current()->nmethods_do(cf);
2707 }
2708 }
2709 }
2710
2711 void JavaThread::metadata_do(void f(Metadata*)) {
2712 Thread::metadata_do(f);
2713 if (has_last_Java_frame()) {
2714 // Traverse the execution stack to call f() on the methods in the stack
2715 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2716 fst.current()->metadata_do(f);
2717 }
2718 } else if (is_Compiler_thread()) {
2719 // need to walk ciMetadata in current compile tasks to keep alive.
2720 CompilerThread* ct = (CompilerThread*)this;
2721 if (ct->env() != NULL) {
2722 ct->env()->metadata_do(f);
2723 }
2724 }
2725 }
2726
2727 // Printing
2728 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2729 switch (_thread_state) {
2730 case _thread_uninitialized: return "_thread_uninitialized";
2731 case _thread_new: return "_thread_new";
2732 case _thread_new_trans: return "_thread_new_trans";
2733 case _thread_in_native: return "_thread_in_native";
2734 case _thread_in_native_trans: return "_thread_in_native_trans";
2735 case _thread_in_vm: return "_thread_in_vm";
2736 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2737 case _thread_in_Java: return "_thread_in_Java";
2738 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2739 case _thread_blocked: return "_thread_blocked";
2740 case _thread_blocked_trans: return "_thread_blocked_trans";
2741 default: return "unknown thread state";
2742 }
2743 }
2744
2745 #ifndef PRODUCT
2746 void JavaThread::print_thread_state_on(outputStream *st) const {
2747 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2748 };
2749 void JavaThread::print_thread_state() const {
2750 print_thread_state_on(tty);
2751 }
2752 #endif // PRODUCT
2753
2754 // Called by Threads::print() for VM_PrintThreads operation
2755 void JavaThread::print_on(outputStream *st) const {
2756 st->print("\"%s\" ", get_thread_name());
2757 oop thread_oop = threadObj();
2758 if (thread_oop != NULL) {
2759 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2760 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2761 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2762 }
2763 Thread::print_on(st);
2764 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2765 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2766 if (thread_oop != NULL) {
2767 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2768 }
2769 #ifndef PRODUCT
2770 print_thread_state_on(st);
2771 _safepoint_state->print_on(st);
2772 #endif // PRODUCT
2773 }
2774
2775 // Called by fatal error handler. The difference between this and
2776 // JavaThread::print() is that we can't grab lock or allocate memory.
2777 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2778 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2779 oop thread_obj = threadObj();
2780 if (thread_obj != NULL) {
2781 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2782 }
2783 st->print(" [");
2784 st->print("%s", _get_thread_state_name(_thread_state));
2785 if (osthread()) {
2786 st->print(", id=%d", osthread()->thread_id());
2787 }
2788 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2789 _stack_base - _stack_size, _stack_base);
2790 st->print("]");
2791 return;
2792 }
2793
2794 // Verification
2795
2796 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2797
2798 void JavaThread::verify() {
2799 // Verify oops in the thread.
2800 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2801
2802 // Verify the stack frames.
2803 frames_do(frame_verify);
2804 }
2805
2806 // CR 6300358 (sub-CR 2137150)
2807 // Most callers of this method assume that it can't return NULL but a
2808 // thread may not have a name whilst it is in the process of attaching to
2809 // the VM - see CR 6412693, and there are places where a JavaThread can be
2810 // seen prior to having it's threadObj set (eg JNI attaching threads and
2811 // if vm exit occurs during initialization). These cases can all be accounted
2812 // for such that this method never returns NULL.
2813 const char* JavaThread::get_thread_name() const {
2814 #ifdef ASSERT
2815 // early safepoints can hit while current thread does not yet have TLS
2816 if (!SafepointSynchronize::is_at_safepoint()) {
2817 Thread *cur = Thread::current();
2818 if (!(cur->is_Java_thread() && cur == this)) {
2819 // Current JavaThreads are allowed to get their own name without
2820 // the Threads_lock.
2821 assert_locked_or_safepoint(Threads_lock);
2822 }
2823 }
2824 #endif // ASSERT
2825 return get_thread_name_string();
2826 }
2827
2828 // Returns a non-NULL representation of this thread's name, or a suitable
2829 // descriptive string if there is no set name
2830 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2831 const char* name_str;
2832 oop thread_obj = threadObj();
2833 if (thread_obj != NULL) {
2834 oop name = java_lang_Thread::name(thread_obj);
2835 if (name != NULL) {
2836 if (buf == NULL) {
2837 name_str = java_lang_String::as_utf8_string(name);
2838 } else {
2839 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2840 }
2841 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2842 name_str = "<no-name - thread is attaching>";
2843 } else {
2844 name_str = Thread::name();
2845 }
2846 } else {
2847 name_str = Thread::name();
2848 }
2849 assert(name_str != NULL, "unexpected NULL thread name");
2850 return name_str;
2851 }
2852
2853
2854 const char* JavaThread::get_threadgroup_name() const {
2855 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2856 oop thread_obj = threadObj();
2857 if (thread_obj != NULL) {
2858 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2859 if (thread_group != NULL) {
2860 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2861 // ThreadGroup.name can be null
2862 if (name != NULL) {
2863 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2864 return str;
2865 }
2866 }
2867 }
2868 return NULL;
2869 }
2870
2871 const char* JavaThread::get_parent_name() const {
2872 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2873 oop thread_obj = threadObj();
2874 if (thread_obj != NULL) {
2875 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2876 if (thread_group != NULL) {
2877 oop parent = java_lang_ThreadGroup::parent(thread_group);
2878 if (parent != NULL) {
2879 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2880 // ThreadGroup.name can be null
2881 if (name != NULL) {
2882 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2883 return str;
2884 }
2885 }
2886 }
2887 }
2888 return NULL;
2889 }
2890
2891 ThreadPriority JavaThread::java_priority() const {
2892 oop thr_oop = threadObj();
2893 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2894 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2895 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2896 return priority;
2897 }
2898
2899 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2900
2901 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2902 // Link Java Thread object <-> C++ Thread
2903
2904 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2905 // and put it into a new Handle. The Handle "thread_oop" can then
2906 // be used to pass the C++ thread object to other methods.
2907
2908 // Set the Java level thread object (jthread) field of the
2909 // new thread (a JavaThread *) to C++ thread object using the
2910 // "thread_oop" handle.
2911
2912 // Set the thread field (a JavaThread *) of the
2913 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2914
2915 Handle thread_oop(Thread::current(),
2916 JNIHandles::resolve_non_null(jni_thread));
2917 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2918 "must be initialized");
2919 set_threadObj(thread_oop());
2920 java_lang_Thread::set_thread(thread_oop(), this);
2921
2922 if (prio == NoPriority) {
2923 prio = java_lang_Thread::priority(thread_oop());
2924 assert(prio != NoPriority, "A valid priority should be present");
2925 }
2926
2927 // Push the Java priority down to the native thread; needs Threads_lock
2928 Thread::set_priority(this, prio);
2929
2930 prepare_ext();
2931
2932 // Add the new thread to the Threads list and set it in motion.
2933 // We must have threads lock in order to call Threads::add.
2934 // It is crucial that we do not block before the thread is
2935 // added to the Threads list for if a GC happens, then the java_thread oop
2936 // will not be visited by GC.
2937 Threads::add(this);
2938 }
2939
2940 oop JavaThread::current_park_blocker() {
2941 // Support for JSR-166 locks
2942 oop thread_oop = threadObj();
2943 if (thread_oop != NULL &&
2944 JDK_Version::current().supports_thread_park_blocker()) {
2945 return java_lang_Thread::park_blocker(thread_oop);
2946 }
2947 return NULL;
2948 }
2949
2950
2951 void JavaThread::print_stack_on(outputStream* st) {
2952 if (!has_last_Java_frame()) return;
2953 ResourceMark rm;
2954 HandleMark hm;
2955
2956 RegisterMap reg_map(this);
2957 vframe* start_vf = last_java_vframe(®_map);
2958 int count = 0;
2959 for (vframe* f = start_vf; f; f = f->sender()) {
2960 if (f->is_java_frame()) {
2961 javaVFrame* jvf = javaVFrame::cast(f);
2962 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2963
2964 // Print out lock information
2965 if (JavaMonitorsInStackTrace) {
2966 jvf->print_lock_info_on(st, count);
2967 }
2968 } else {
2969 // Ignore non-Java frames
2970 }
2971
2972 // Bail-out case for too deep stacks
2973 count++;
2974 if (MaxJavaStackTraceDepth == count) return;
2975 }
2976 }
2977
2978
2979 // JVMTI PopFrame support
2980 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2981 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2982 if (in_bytes(size_in_bytes) != 0) {
2983 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
2984 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2985 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2986 }
2987 }
2988
2989 void* JavaThread::popframe_preserved_args() {
2990 return _popframe_preserved_args;
2991 }
2992
2993 ByteSize JavaThread::popframe_preserved_args_size() {
2994 return in_ByteSize(_popframe_preserved_args_size);
2995 }
2996
2997 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2998 int sz = in_bytes(popframe_preserved_args_size());
2999 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3000 return in_WordSize(sz / wordSize);
3001 }
3002
3003 void JavaThread::popframe_free_preserved_args() {
3004 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3005 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3006 _popframe_preserved_args = NULL;
3007 _popframe_preserved_args_size = 0;
3008 }
3009
3010 #ifndef PRODUCT
3011
3012 void JavaThread::trace_frames() {
3013 tty->print_cr("[Describe stack]");
3014 int frame_no = 1;
3015 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3016 tty->print(" %d. ", frame_no++);
3017 fst.current()->print_value_on(tty, this);
3018 tty->cr();
3019 }
3020 }
3021
3022 class PrintAndVerifyOopClosure: public OopClosure {
3023 protected:
3024 template <class T> inline void do_oop_work(T* p) {
3025 oop obj = oopDesc::load_decode_heap_oop(p);
3026 if (obj == NULL) return;
3027 tty->print(INTPTR_FORMAT ": ", p);
3028 if (obj->is_oop_or_null()) {
3029 if (obj->is_objArray()) {
3030 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3031 } else {
3032 obj->print();
3033 }
3034 } else {
3035 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3036 }
3037 tty->cr();
3038 }
3039 public:
3040 virtual void do_oop(oop* p) { do_oop_work(p); }
3041 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3042 };
3043
3044
3045 static void oops_print(frame* f, const RegisterMap *map) {
3046 PrintAndVerifyOopClosure print;
3047 f->print_value();
3048 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3049 }
3050
3051 // Print our all the locations that contain oops and whether they are
3052 // valid or not. This useful when trying to find the oldest frame
3053 // where an oop has gone bad since the frame walk is from youngest to
3054 // oldest.
3055 void JavaThread::trace_oops() {
3056 tty->print_cr("[Trace oops]");
3057 frames_do(oops_print);
3058 }
3059
3060
3061 #ifdef ASSERT
3062 // Print or validate the layout of stack frames
3063 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3064 ResourceMark rm;
3065 PRESERVE_EXCEPTION_MARK;
3066 FrameValues values;
3067 int frame_no = 0;
3068 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3069 fst.current()->describe(values, ++frame_no);
3070 if (depth == frame_no) break;
3071 }
3072 if (validate_only) {
3073 values.validate();
3074 } else {
3075 tty->print_cr("[Describe stack layout]");
3076 values.print(this);
3077 }
3078 }
3079 #endif
3080
3081 void JavaThread::trace_stack_from(vframe* start_vf) {
3082 ResourceMark rm;
3083 int vframe_no = 1;
3084 for (vframe* f = start_vf; f; f = f->sender()) {
3085 if (f->is_java_frame()) {
3086 javaVFrame::cast(f)->print_activation(vframe_no++);
3087 } else {
3088 f->print();
3089 }
3090 if (vframe_no > StackPrintLimit) {
3091 tty->print_cr("...<more frames>...");
3092 return;
3093 }
3094 }
3095 }
3096
3097
3098 void JavaThread::trace_stack() {
3099 if (!has_last_Java_frame()) return;
3100 ResourceMark rm;
3101 HandleMark hm;
3102 RegisterMap reg_map(this);
3103 trace_stack_from(last_java_vframe(®_map));
3104 }
3105
3106
3107 #endif // PRODUCT
3108
3109
3110 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3111 assert(reg_map != NULL, "a map must be given");
3112 frame f = last_frame();
3113 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3114 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3115 }
3116 return NULL;
3117 }
3118
3119
3120 Klass* JavaThread::security_get_caller_class(int depth) {
3121 vframeStream vfst(this);
3122 vfst.security_get_caller_frame(depth);
3123 if (!vfst.at_end()) {
3124 return vfst.method()->method_holder();
3125 }
3126 return NULL;
3127 }
3128
3129 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3130 assert(thread->is_Compiler_thread(), "must be compiler thread");
3131 CompileBroker::compiler_thread_loop();
3132 }
3133
3134 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3135 NMethodSweeper::sweeper_loop();
3136 }
3137
3138 // Create a CompilerThread
3139 CompilerThread::CompilerThread(CompileQueue* queue,
3140 CompilerCounters* counters)
3141 : JavaThread(&compiler_thread_entry) {
3142 _env = NULL;
3143 _log = NULL;
3144 _task = NULL;
3145 _queue = queue;
3146 _counters = counters;
3147 _buffer_blob = NULL;
3148 _compiler = NULL;
3149
3150 #ifndef PRODUCT
3151 _ideal_graph_printer = NULL;
3152 #endif
3153 }
3154
3155 // Create sweeper thread
3156 CodeCacheSweeperThread::CodeCacheSweeperThread()
3157 : JavaThread(&sweeper_thread_entry) {
3158 _scanned_nmethod = NULL;
3159 }
3160 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3161 JavaThread::oops_do(f, cld_f, cf);
3162 if (_scanned_nmethod != NULL && cf != NULL) {
3163 // Safepoints can occur when the sweeper is scanning an nmethod so
3164 // process it here to make sure it isn't unloaded in the middle of
3165 // a scan.
3166 cf->do_code_blob(_scanned_nmethod);
3167 }
3168 }
3169
3170
3171 // ======= Threads ========
3172
3173 // The Threads class links together all active threads, and provides
3174 // operations over all threads. It is protected by its own Mutex
3175 // lock, which is also used in other contexts to protect thread
3176 // operations from having the thread being operated on from exiting
3177 // and going away unexpectedly (e.g., safepoint synchronization)
3178
3179 JavaThread* Threads::_thread_list = NULL;
3180 int Threads::_number_of_threads = 0;
3181 int Threads::_number_of_non_daemon_threads = 0;
3182 int Threads::_return_code = 0;
3183 size_t JavaThread::_stack_size_at_create = 0;
3184 #ifdef ASSERT
3185 bool Threads::_vm_complete = false;
3186 #endif
3187
3188 // All JavaThreads
3189 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3190
3191 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3192 void Threads::threads_do(ThreadClosure* tc) {
3193 assert_locked_or_safepoint(Threads_lock);
3194 // ALL_JAVA_THREADS iterates through all JavaThreads
3195 ALL_JAVA_THREADS(p) {
3196 tc->do_thread(p);
3197 }
3198 // Someday we could have a table or list of all non-JavaThreads.
3199 // For now, just manually iterate through them.
3200 tc->do_thread(VMThread::vm_thread());
3201 Universe::heap()->gc_threads_do(tc);
3202 WatcherThread *wt = WatcherThread::watcher_thread();
3203 // Strictly speaking, the following NULL check isn't sufficient to make sure
3204 // the data for WatcherThread is still valid upon being examined. However,
3205 // considering that WatchThread terminates when the VM is on the way to
3206 // exit at safepoint, the chance of the above is extremely small. The right
3207 // way to prevent termination of WatcherThread would be to acquire
3208 // Terminator_lock, but we can't do that without violating the lock rank
3209 // checking in some cases.
3210 if (wt != NULL) {
3211 tc->do_thread(wt);
3212 }
3213
3214 // If CompilerThreads ever become non-JavaThreads, add them here
3215 }
3216
3217
3218 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3219 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3220
3221 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3222 create_vm_init_libraries();
3223 }
3224
3225 initialize_class(vmSymbols::java_lang_String(), CHECK);
3226
3227 // Initialize java_lang.System (needed before creating the thread)
3228 initialize_class(vmSymbols::java_lang_System(), CHECK);
3229 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3230 Handle thread_group = create_initial_thread_group(CHECK);
3231 Universe::set_main_thread_group(thread_group());
3232 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3233 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3234 main_thread->set_threadObj(thread_object);
3235 // Set thread status to running since main thread has
3236 // been started and running.
3237 java_lang_Thread::set_thread_status(thread_object,
3238 java_lang_Thread::RUNNABLE);
3239
3240 // The VM creates & returns objects of this class. Make sure it's initialized.
3241 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3242
3243 // The VM preresolves methods to these classes. Make sure that they get initialized
3244 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3245 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3246 call_initializeSystemClass(CHECK);
3247
3248 // get the Java runtime name after java.lang.System is initialized
3249 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3250 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3251
3252 // an instance of OutOfMemory exception has been allocated earlier
3253 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3254 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3255 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3256 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3257 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3258 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3259 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3260 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3261 }
3262
3263 void Threads::initialize_jsr292_core_classes(TRAPS) {
3264 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3265 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3266 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3267 }
3268
3269 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3270 extern void JDK_Version_init();
3271
3272 // Check version
3273 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3274
3275 // Initialize the output stream module
3276 ostream_init();
3277
3278 // Process java launcher properties.
3279 Arguments::process_sun_java_launcher_properties(args);
3280
3281 // Initialize the os module before using TLS
3282 os::init();
3283
3284 // Initialize system properties.
3285 Arguments::init_system_properties();
3286
3287 // So that JDK version can be used as a discriminator when parsing arguments
3288 JDK_Version_init();
3289
3290 // Update/Initialize System properties after JDK version number is known
3291 Arguments::init_version_specific_system_properties();
3292
3293 // Parse arguments
3294 jint parse_result = Arguments::parse(args);
3295 if (parse_result != JNI_OK) return parse_result;
3296
3297 os::init_before_ergo();
3298
3299 jint ergo_result = Arguments::apply_ergo();
3300 if (ergo_result != JNI_OK) return ergo_result;
3301
3302 if (PauseAtStartup) {
3303 os::pause();
3304 }
3305
3306 HOTSPOT_VM_INIT_BEGIN();
3307
3308 // Record VM creation timing statistics
3309 TraceVmCreationTime create_vm_timer;
3310 create_vm_timer.start();
3311
3312 // Timing (must come after argument parsing)
3313 TraceTime timer("Create VM", TraceStartupTime);
3314
3315 // Initialize the os module after parsing the args
3316 jint os_init_2_result = os::init_2();
3317 if (os_init_2_result != JNI_OK) return os_init_2_result;
3318
3319 jint adjust_after_os_result = Arguments::adjust_after_os();
3320 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3321
3322 // initialize TLS
3323 ThreadLocalStorage::init();
3324
3325 // Initialize output stream logging
3326 ostream_init_log();
3327
3328 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3329 // Must be before create_vm_init_agents()
3330 if (Arguments::init_libraries_at_startup()) {
3331 convert_vm_init_libraries_to_agents();
3332 }
3333
3334 // Launch -agentlib/-agentpath and converted -Xrun agents
3335 if (Arguments::init_agents_at_startup()) {
3336 create_vm_init_agents();
3337 }
3338
3339 // Initialize Threads state
3340 _thread_list = NULL;
3341 _number_of_threads = 0;
3342 _number_of_non_daemon_threads = 0;
3343
3344 // Initialize global data structures and create system classes in heap
3345 vm_init_globals();
3346
3347 // Attach the main thread to this os thread
3348 JavaThread* main_thread = new JavaThread();
3349 main_thread->set_thread_state(_thread_in_vm);
3350 // must do this before set_active_handles and initialize_thread_local_storage
3351 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3352 // change the stack size recorded here to one based on the java thread
3353 // stacksize. This adjusted size is what is used to figure the placement
3354 // of the guard pages.
3355 main_thread->record_stack_base_and_size();
3356 main_thread->initialize_thread_local_storage();
3357
3358 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3359
3360 if (!main_thread->set_as_starting_thread()) {
3361 vm_shutdown_during_initialization(
3362 "Failed necessary internal allocation. Out of swap space");
3363 delete main_thread;
3364 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3365 return JNI_ENOMEM;
3366 }
3367
3368 // Enable guard page *after* os::create_main_thread(), otherwise it would
3369 // crash Linux VM, see notes in os_linux.cpp.
3370 main_thread->create_stack_guard_pages();
3371
3372 // Initialize Java-Level synchronization subsystem
3373 ObjectMonitor::Initialize();
3374
3375 // Initialize global modules
3376 jint status = init_globals();
3377 if (status != JNI_OK) {
3378 delete main_thread;
3379 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3380 return status;
3381 }
3382
3383 // Should be done after the heap is fully created
3384 main_thread->cache_global_variables();
3385
3386 HandleMark hm;
3387
3388 { MutexLocker mu(Threads_lock);
3389 Threads::add(main_thread);
3390 }
3391
3392 // Any JVMTI raw monitors entered in onload will transition into
3393 // real raw monitor. VM is setup enough here for raw monitor enter.
3394 JvmtiExport::transition_pending_onload_raw_monitors();
3395
3396 // Create the VMThread
3397 { TraceTime timer("Start VMThread", TraceStartupTime);
3398 VMThread::create();
3399 Thread* vmthread = VMThread::vm_thread();
3400
3401 if (!os::create_thread(vmthread, os::vm_thread)) {
3402 vm_exit_during_initialization("Cannot create VM thread. "
3403 "Out of system resources.");
3404 }
3405
3406 // Wait for the VM thread to become ready, and VMThread::run to initialize
3407 // Monitors can have spurious returns, must always check another state flag
3408 {
3409 MutexLocker ml(Notify_lock);
3410 os::start_thread(vmthread);
3411 while (vmthread->active_handles() == NULL) {
3412 Notify_lock->wait();
3413 }
3414 }
3415 }
3416
3417 assert(Universe::is_fully_initialized(), "not initialized");
3418 if (VerifyDuringStartup) {
3419 // Make sure we're starting with a clean slate.
3420 VM_Verify verify_op;
3421 VMThread::execute(&verify_op);
3422 }
3423
3424 Thread* THREAD = Thread::current();
3425
3426 // At this point, the Universe is initialized, but we have not executed
3427 // any byte code. Now is a good time (the only time) to dump out the
3428 // internal state of the JVM for sharing.
3429 if (DumpSharedSpaces) {
3430 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3431 ShouldNotReachHere();
3432 }
3433
3434 // Always call even when there are not JVMTI environments yet, since environments
3435 // may be attached late and JVMTI must track phases of VM execution
3436 JvmtiExport::enter_start_phase();
3437
3438 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3439 JvmtiExport::post_vm_start();
3440
3441 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3442
3443 // We need this for ClassDataSharing - the initial vm.info property is set
3444 // with the default value of CDS "sharing" which may be reset through
3445 // command line options.
3446 reset_vm_info_property(CHECK_JNI_ERR);
3447
3448 quicken_jni_functions();
3449
3450 // Must be run after init_ft which initializes ft_enabled
3451 if (TRACE_INITIALIZE() != JNI_OK) {
3452 vm_exit_during_initialization("Failed to initialize tracing backend");
3453 }
3454
3455 // Set flag that basic initialization has completed. Used by exceptions and various
3456 // debug stuff, that does not work until all basic classes have been initialized.
3457 set_init_completed();
3458
3459 Metaspace::post_initialize();
3460
3461 HOTSPOT_VM_INIT_END();
3462
3463 // record VM initialization completion time
3464 #if INCLUDE_MANAGEMENT
3465 Management::record_vm_init_completed();
3466 #endif // INCLUDE_MANAGEMENT
3467
3468 // Compute system loader. Note that this has to occur after set_init_completed, since
3469 // valid exceptions may be thrown in the process.
3470 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3471 // set_init_completed has just been called, causing exceptions not to be shortcut
3472 // anymore. We call vm_exit_during_initialization directly instead.
3473 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3474
3475 #if INCLUDE_ALL_GCS
3476 // Support for ConcurrentMarkSweep. This should be cleaned up
3477 // and better encapsulated. The ugly nested if test would go away
3478 // once things are properly refactored. XXX YSR
3479 if (UseConcMarkSweepGC || UseG1GC) {
3480 if (UseConcMarkSweepGC) {
3481 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3482 } else {
3483 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3484 }
3485 }
3486 #endif // INCLUDE_ALL_GCS
3487
3488 // Always call even when there are not JVMTI environments yet, since environments
3489 // may be attached late and JVMTI must track phases of VM execution
3490 JvmtiExport::enter_live_phase();
3491
3492 // Signal Dispatcher needs to be started before VMInit event is posted
3493 os::signal_init();
3494
3495 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3496 if (!DisableAttachMechanism) {
3497 AttachListener::vm_start();
3498 if (StartAttachListener || AttachListener::init_at_startup()) {
3499 AttachListener::init();
3500 }
3501 }
3502
3503 // Launch -Xrun agents
3504 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3505 // back-end can launch with -Xdebug -Xrunjdwp.
3506 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3507 create_vm_init_libraries();
3508 }
3509
3510 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3511 JvmtiExport::post_vm_initialized();
3512
3513 if (TRACE_START() != JNI_OK) {
3514 vm_exit_during_initialization("Failed to start tracing backend.");
3515 }
3516
3517 if (CleanChunkPoolAsync) {
3518 Chunk::start_chunk_pool_cleaner_task();
3519 }
3520
3521 // initialize compiler(s)
3522 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3523 CompileBroker::compilation_init();
3524 #endif
3525
3526 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3527 // It is done after compilers are initialized, because otherwise compilations of
3528 // signature polymorphic MH intrinsics can be missed
3529 // (see SystemDictionary::find_method_handle_intrinsic).
3530 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3531
3532 #if INCLUDE_MANAGEMENT
3533 Management::initialize(THREAD);
3534
3535 if (HAS_PENDING_EXCEPTION) {
3536 // management agent fails to start possibly due to
3537 // configuration problem and is responsible for printing
3538 // stack trace if appropriate. Simply exit VM.
3539 vm_exit(1);
3540 }
3541 #endif // INCLUDE_MANAGEMENT
3542
3543 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3544 if (MemProfiling) MemProfiler::engage();
3545 StatSampler::engage();
3546 if (CheckJNICalls) JniPeriodicChecker::engage();
3547
3548 BiasedLocking::init();
3549
3550 #if INCLUDE_RTM_OPT
3551 RTMLockingCounters::init();
3552 #endif
3553
3554 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3555 call_postVMInitHook(THREAD);
3556 // The Java side of PostVMInitHook.run must deal with all
3557 // exceptions and provide means of diagnosis.
3558 if (HAS_PENDING_EXCEPTION) {
3559 CLEAR_PENDING_EXCEPTION;
3560 }
3561 }
3562
3563 {
3564 MutexLocker ml(PeriodicTask_lock);
3565 // Make sure the WatcherThread can be started by WatcherThread::start()
3566 // or by dynamic enrollment.
3567 WatcherThread::make_startable();
3568 // Start up the WatcherThread if there are any periodic tasks
3569 // NOTE: All PeriodicTasks should be registered by now. If they
3570 // aren't, late joiners might appear to start slowly (we might
3571 // take a while to process their first tick).
3572 if (PeriodicTask::num_tasks() > 0) {
3573 WatcherThread::start();
3574 }
3575 }
3576
3577 create_vm_timer.end();
3578 #ifdef ASSERT
3579 _vm_complete = true;
3580 #endif
3581 return JNI_OK;
3582 }
3583
3584 // type for the Agent_OnLoad and JVM_OnLoad entry points
3585 extern "C" {
3586 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3587 }
3588 // Find a command line agent library and return its entry point for
3589 // -agentlib: -agentpath: -Xrun
3590 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3591 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3592 const char *on_load_symbols[],
3593 size_t num_symbol_entries) {
3594 OnLoadEntry_t on_load_entry = NULL;
3595 void *library = NULL;
3596
3597 if (!agent->valid()) {
3598 char buffer[JVM_MAXPATHLEN];
3599 char ebuf[1024] = "";
3600 const char *name = agent->name();
3601 const char *msg = "Could not find agent library ";
3602
3603 // First check to see if agent is statically linked into executable
3604 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3605 library = agent->os_lib();
3606 } else if (agent->is_absolute_path()) {
3607 library = os::dll_load(name, ebuf, sizeof ebuf);
3608 if (library == NULL) {
3609 const char *sub_msg = " in absolute path, with error: ";
3610 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3611 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3612 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3613 // If we can't find the agent, exit.
3614 vm_exit_during_initialization(buf, NULL);
3615 FREE_C_HEAP_ARRAY(char, buf);
3616 }
3617 } else {
3618 // Try to load the agent from the standard dll directory
3619 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3620 name)) {
3621 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3622 }
3623 if (library == NULL) { // Try the local directory
3624 char ns[1] = {0};
3625 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3626 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3627 }
3628 if (library == NULL) {
3629 const char *sub_msg = " on the library path, with error: ";
3630 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3631 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3632 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3633 // If we can't find the agent, exit.
3634 vm_exit_during_initialization(buf, NULL);
3635 FREE_C_HEAP_ARRAY(char, buf);
3636 }
3637 }
3638 }
3639 agent->set_os_lib(library);
3640 agent->set_valid();
3641 }
3642
3643 // Find the OnLoad function.
3644 on_load_entry =
3645 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3646 false,
3647 on_load_symbols,
3648 num_symbol_entries));
3649 return on_load_entry;
3650 }
3651
3652 // Find the JVM_OnLoad entry point
3653 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3654 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3655 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3656 }
3657
3658 // Find the Agent_OnLoad entry point
3659 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3660 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3661 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3662 }
3663
3664 // For backwards compatibility with -Xrun
3665 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3666 // treated like -agentpath:
3667 // Must be called before agent libraries are created
3668 void Threads::convert_vm_init_libraries_to_agents() {
3669 AgentLibrary* agent;
3670 AgentLibrary* next;
3671
3672 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3673 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3674 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3675
3676 // If there is an JVM_OnLoad function it will get called later,
3677 // otherwise see if there is an Agent_OnLoad
3678 if (on_load_entry == NULL) {
3679 on_load_entry = lookup_agent_on_load(agent);
3680 if (on_load_entry != NULL) {
3681 // switch it to the agent list -- so that Agent_OnLoad will be called,
3682 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3683 Arguments::convert_library_to_agent(agent);
3684 } else {
3685 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3686 }
3687 }
3688 }
3689 }
3690
3691 // Create agents for -agentlib: -agentpath: and converted -Xrun
3692 // Invokes Agent_OnLoad
3693 // Called very early -- before JavaThreads exist
3694 void Threads::create_vm_init_agents() {
3695 extern struct JavaVM_ main_vm;
3696 AgentLibrary* agent;
3697
3698 JvmtiExport::enter_onload_phase();
3699
3700 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3701 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3702
3703 if (on_load_entry != NULL) {
3704 // Invoke the Agent_OnLoad function
3705 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3706 if (err != JNI_OK) {
3707 vm_exit_during_initialization("agent library failed to init", agent->name());
3708 }
3709 } else {
3710 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3711 }
3712 }
3713 JvmtiExport::enter_primordial_phase();
3714 }
3715
3716 extern "C" {
3717 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3718 }
3719
3720 void Threads::shutdown_vm_agents() {
3721 // Send any Agent_OnUnload notifications
3722 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3723 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3724 extern struct JavaVM_ main_vm;
3725 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3726
3727 // Find the Agent_OnUnload function.
3728 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3729 os::find_agent_function(agent,
3730 false,
3731 on_unload_symbols,
3732 num_symbol_entries));
3733
3734 // Invoke the Agent_OnUnload function
3735 if (unload_entry != NULL) {
3736 JavaThread* thread = JavaThread::current();
3737 ThreadToNativeFromVM ttn(thread);
3738 HandleMark hm(thread);
3739 (*unload_entry)(&main_vm);
3740 }
3741 }
3742 }
3743
3744 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3745 // Invokes JVM_OnLoad
3746 void Threads::create_vm_init_libraries() {
3747 extern struct JavaVM_ main_vm;
3748 AgentLibrary* agent;
3749
3750 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3751 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3752
3753 if (on_load_entry != NULL) {
3754 // Invoke the JVM_OnLoad function
3755 JavaThread* thread = JavaThread::current();
3756 ThreadToNativeFromVM ttn(thread);
3757 HandleMark hm(thread);
3758 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3759 if (err != JNI_OK) {
3760 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3761 }
3762 } else {
3763 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3764 }
3765 }
3766 }
3767
3768 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3769 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3770
3771 JavaThread* java_thread = NULL;
3772 // Sequential search for now. Need to do better optimization later.
3773 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3774 oop tobj = thread->threadObj();
3775 if (!thread->is_exiting() &&
3776 tobj != NULL &&
3777 java_tid == java_lang_Thread::thread_id(tobj)) {
3778 java_thread = thread;
3779 break;
3780 }
3781 }
3782 return java_thread;
3783 }
3784
3785
3786 // Last thread running calls java.lang.Shutdown.shutdown()
3787 void JavaThread::invoke_shutdown_hooks() {
3788 HandleMark hm(this);
3789
3790 // We could get here with a pending exception, if so clear it now.
3791 if (this->has_pending_exception()) {
3792 this->clear_pending_exception();
3793 }
3794
3795 EXCEPTION_MARK;
3796 Klass* k =
3797 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3798 THREAD);
3799 if (k != NULL) {
3800 // SystemDictionary::resolve_or_null will return null if there was
3801 // an exception. If we cannot load the Shutdown class, just don't
3802 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3803 // and finalizers (if runFinalizersOnExit is set) won't be run.
3804 // Note that if a shutdown hook was registered or runFinalizersOnExit
3805 // was called, the Shutdown class would have already been loaded
3806 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3807 instanceKlassHandle shutdown_klass (THREAD, k);
3808 JavaValue result(T_VOID);
3809 JavaCalls::call_static(&result,
3810 shutdown_klass,
3811 vmSymbols::shutdown_method_name(),
3812 vmSymbols::void_method_signature(),
3813 THREAD);
3814 }
3815 CLEAR_PENDING_EXCEPTION;
3816 }
3817
3818 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3819 // the program falls off the end of main(). Another VM exit path is through
3820 // vm_exit() when the program calls System.exit() to return a value or when
3821 // there is a serious error in VM. The two shutdown paths are not exactly
3822 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3823 // and VM_Exit op at VM level.
3824 //
3825 // Shutdown sequence:
3826 // + Shutdown native memory tracking if it is on
3827 // + Wait until we are the last non-daemon thread to execute
3828 // <-- every thing is still working at this moment -->
3829 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3830 // shutdown hooks, run finalizers if finalization-on-exit
3831 // + Call before_exit(), prepare for VM exit
3832 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3833 // currently the only user of this mechanism is File.deleteOnExit())
3834 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3835 // post thread end and vm death events to JVMTI,
3836 // stop signal thread
3837 // + Call JavaThread::exit(), it will:
3838 // > release JNI handle blocks, remove stack guard pages
3839 // > remove this thread from Threads list
3840 // <-- no more Java code from this thread after this point -->
3841 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3842 // the compiler threads at safepoint
3843 // <-- do not use anything that could get blocked by Safepoint -->
3844 // + Disable tracing at JNI/JVM barriers
3845 // + Set _vm_exited flag for threads that are still running native code
3846 // + Delete this thread
3847 // + Call exit_globals()
3848 // > deletes tty
3849 // > deletes PerfMemory resources
3850 // + Return to caller
3851
3852 bool Threads::destroy_vm() {
3853 JavaThread* thread = JavaThread::current();
3854
3855 #ifdef ASSERT
3856 _vm_complete = false;
3857 #endif
3858 // Wait until we are the last non-daemon thread to execute
3859 { MutexLocker nu(Threads_lock);
3860 while (Threads::number_of_non_daemon_threads() > 1)
3861 // This wait should make safepoint checks, wait without a timeout,
3862 // and wait as a suspend-equivalent condition.
3863 //
3864 // Note: If the FlatProfiler is running and this thread is waiting
3865 // for another non-daemon thread to finish, then the FlatProfiler
3866 // is waiting for the external suspend request on this thread to
3867 // complete. wait_for_ext_suspend_completion() will eventually
3868 // timeout, but that takes time. Making this wait a suspend-
3869 // equivalent condition solves that timeout problem.
3870 //
3871 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3872 Mutex::_as_suspend_equivalent_flag);
3873 }
3874
3875 // Hang forever on exit if we are reporting an error.
3876 if (ShowMessageBoxOnError && is_error_reported()) {
3877 os::infinite_sleep();
3878 }
3879 os::wait_for_keypress_at_exit();
3880
3881 // run Java level shutdown hooks
3882 thread->invoke_shutdown_hooks();
3883
3884 before_exit(thread);
3885
3886 thread->exit(true);
3887
3888 // Stop VM thread.
3889 {
3890 // 4945125 The vm thread comes to a safepoint during exit.
3891 // GC vm_operations can get caught at the safepoint, and the
3892 // heap is unparseable if they are caught. Grab the Heap_lock
3893 // to prevent this. The GC vm_operations will not be able to
3894 // queue until after the vm thread is dead. After this point,
3895 // we'll never emerge out of the safepoint before the VM exits.
3896
3897 MutexLocker ml(Heap_lock);
3898
3899 VMThread::wait_for_vm_thread_exit();
3900 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3901 VMThread::destroy();
3902 }
3903
3904 // clean up ideal graph printers
3905 #if defined(COMPILER2) && !defined(PRODUCT)
3906 IdealGraphPrinter::clean_up();
3907 #endif
3908
3909 // Now, all Java threads are gone except daemon threads. Daemon threads
3910 // running Java code or in VM are stopped by the Safepoint. However,
3911 // daemon threads executing native code are still running. But they
3912 // will be stopped at native=>Java/VM barriers. Note that we can't
3913 // simply kill or suspend them, as it is inherently deadlock-prone.
3914
3915 #ifndef PRODUCT
3916 // disable function tracing at JNI/JVM barriers
3917 TraceJNICalls = false;
3918 TraceJVMCalls = false;
3919 TraceRuntimeCalls = false;
3920 #endif
3921
3922 VM_Exit::set_vm_exited();
3923
3924 notify_vm_shutdown();
3925
3926 delete thread;
3927
3928 // exit_globals() will delete tty
3929 exit_globals();
3930
3931 return true;
3932 }
3933
3934
3935 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3936 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3937 return is_supported_jni_version(version);
3938 }
3939
3940
3941 jboolean Threads::is_supported_jni_version(jint version) {
3942 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3943 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3944 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3945 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3946 return JNI_FALSE;
3947 }
3948
3949
3950 void Threads::add(JavaThread* p, bool force_daemon) {
3951 // The threads lock must be owned at this point
3952 assert_locked_or_safepoint(Threads_lock);
3953
3954 // See the comment for this method in thread.hpp for its purpose and
3955 // why it is called here.
3956 p->initialize_queues();
3957 p->set_next(_thread_list);
3958 _thread_list = p;
3959 _number_of_threads++;
3960 oop threadObj = p->threadObj();
3961 bool daemon = true;
3962 // Bootstrapping problem: threadObj can be null for initial
3963 // JavaThread (or for threads attached via JNI)
3964 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3965 _number_of_non_daemon_threads++;
3966 daemon = false;
3967 }
3968
3969 ThreadService::add_thread(p, daemon);
3970
3971 // Possible GC point.
3972 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
3973 }
3974
3975 void Threads::remove(JavaThread* p) {
3976 // Extra scope needed for Thread_lock, so we can check
3977 // that we do not remove thread without safepoint code notice
3978 { MutexLocker ml(Threads_lock);
3979
3980 assert(includes(p), "p must be present");
3981
3982 JavaThread* current = _thread_list;
3983 JavaThread* prev = NULL;
3984
3985 while (current != p) {
3986 prev = current;
3987 current = current->next();
3988 }
3989
3990 if (prev) {
3991 prev->set_next(current->next());
3992 } else {
3993 _thread_list = p->next();
3994 }
3995 _number_of_threads--;
3996 oop threadObj = p->threadObj();
3997 bool daemon = true;
3998 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
3999 _number_of_non_daemon_threads--;
4000 daemon = false;
4001
4002 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4003 // on destroy_vm will wake up.
4004 if (number_of_non_daemon_threads() == 1) {
4005 Threads_lock->notify_all();
4006 }
4007 }
4008 ThreadService::remove_thread(p, daemon);
4009
4010 // Make sure that safepoint code disregard this thread. This is needed since
4011 // the thread might mess around with locks after this point. This can cause it
4012 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4013 // of this thread since it is removed from the queue.
4014 p->set_terminated_value();
4015 } // unlock Threads_lock
4016
4017 // Since Events::log uses a lock, we grab it outside the Threads_lock
4018 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4019 }
4020
4021 // Threads_lock must be held when this is called (or must be called during a safepoint)
4022 bool Threads::includes(JavaThread* p) {
4023 assert(Threads_lock->is_locked(), "sanity check");
4024 ALL_JAVA_THREADS(q) {
4025 if (q == p) {
4026 return true;
4027 }
4028 }
4029 return false;
4030 }
4031
4032 // Operations on the Threads list for GC. These are not explicitly locked,
4033 // but the garbage collector must provide a safe context for them to run.
4034 // In particular, these things should never be called when the Threads_lock
4035 // is held by some other thread. (Note: the Safepoint abstraction also
4036 // uses the Threads_lock to guarantee this property. It also makes sure that
4037 // all threads gets blocked when exiting or starting).
4038
4039 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4040 ALL_JAVA_THREADS(p) {
4041 p->oops_do(f, cld_f, cf);
4042 }
4043 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4044 }
4045
4046 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4047 // Introduce a mechanism allowing parallel threads to claim threads as
4048 // root groups. Overhead should be small enough to use all the time,
4049 // even in sequential code.
4050 SharedHeap* sh = SharedHeap::heap();
4051 // Cannot yet substitute active_workers for n_par_threads
4052 // because of G1CollectedHeap::verify() use of
4053 // SharedHeap::process_roots(). n_par_threads == 0 will
4054 // turn off parallelism in process_roots while active_workers
4055 // is being used for parallelism elsewhere.
4056 bool is_par = sh->n_par_threads() > 0;
4057 assert(!is_par ||
4058 (SharedHeap::heap()->n_par_threads() ==
4059 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4060 int cp = SharedHeap::heap()->strong_roots_parity();
4061 ALL_JAVA_THREADS(p) {
4062 if (p->claim_oops_do(is_par, cp)) {
4063 p->oops_do(f, cld_f, cf);
4064 }
4065 }
4066 VMThread* vmt = VMThread::vm_thread();
4067 if (vmt->claim_oops_do(is_par, cp)) {
4068 vmt->oops_do(f, cld_f, cf);
4069 }
4070 }
4071
4072 #if INCLUDE_ALL_GCS
4073 // Used by ParallelScavenge
4074 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4075 ALL_JAVA_THREADS(p) {
4076 q->enqueue(new ThreadRootsTask(p));
4077 }
4078 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4079 }
4080
4081 // Used by Parallel Old
4082 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4083 ALL_JAVA_THREADS(p) {
4084 q->enqueue(new ThreadRootsMarkingTask(p));
4085 }
4086 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4087 }
4088 #endif // INCLUDE_ALL_GCS
4089
4090 void Threads::nmethods_do(CodeBlobClosure* cf) {
4091 ALL_JAVA_THREADS(p) {
4092 p->nmethods_do(cf);
4093 }
4094 VMThread::vm_thread()->nmethods_do(cf);
4095 }
4096
4097 void Threads::metadata_do(void f(Metadata*)) {
4098 ALL_JAVA_THREADS(p) {
4099 p->metadata_do(f);
4100 }
4101 }
4102
4103 void Threads::deoptimized_wrt_marked_nmethods() {
4104 ALL_JAVA_THREADS(p) {
4105 p->deoptimized_wrt_marked_nmethods();
4106 }
4107 }
4108
4109
4110 // Get count Java threads that are waiting to enter the specified monitor.
4111 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4112 address monitor,
4113 bool doLock) {
4114 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4115 "must grab Threads_lock or be at safepoint");
4116 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4117
4118 int i = 0;
4119 {
4120 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4121 ALL_JAVA_THREADS(p) {
4122 if (p->is_Compiler_thread()) continue;
4123
4124 address pending = (address)p->current_pending_monitor();
4125 if (pending == monitor) { // found a match
4126 if (i < count) result->append(p); // save the first count matches
4127 i++;
4128 }
4129 }
4130 }
4131 return result;
4132 }
4133
4134
4135 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4136 bool doLock) {
4137 assert(doLock ||
4138 Threads_lock->owned_by_self() ||
4139 SafepointSynchronize::is_at_safepoint(),
4140 "must grab Threads_lock or be at safepoint");
4141
4142 // NULL owner means not locked so we can skip the search
4143 if (owner == NULL) return NULL;
4144
4145 {
4146 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4147 ALL_JAVA_THREADS(p) {
4148 // first, see if owner is the address of a Java thread
4149 if (owner == (address)p) return p;
4150 }
4151 }
4152 // Cannot assert on lack of success here since this function may be
4153 // used by code that is trying to report useful problem information
4154 // like deadlock detection.
4155 if (UseHeavyMonitors) return NULL;
4156
4157 // If we didn't find a matching Java thread and we didn't force use of
4158 // heavyweight monitors, then the owner is the stack address of the
4159 // Lock Word in the owning Java thread's stack.
4160 //
4161 JavaThread* the_owner = NULL;
4162 {
4163 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4164 ALL_JAVA_THREADS(q) {
4165 if (q->is_lock_owned(owner)) {
4166 the_owner = q;
4167 break;
4168 }
4169 }
4170 }
4171 // cannot assert on lack of success here; see above comment
4172 return the_owner;
4173 }
4174
4175 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4176 void Threads::print_on(outputStream* st, bool print_stacks,
4177 bool internal_format, bool print_concurrent_locks) {
4178 char buf[32];
4179 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4180
4181 st->print_cr("Full thread dump %s (%s %s):",
4182 Abstract_VM_Version::vm_name(),
4183 Abstract_VM_Version::vm_release(),
4184 Abstract_VM_Version::vm_info_string());
4185 st->cr();
4186
4187 #if INCLUDE_ALL_GCS
4188 // Dump concurrent locks
4189 ConcurrentLocksDump concurrent_locks;
4190 if (print_concurrent_locks) {
4191 concurrent_locks.dump_at_safepoint();
4192 }
4193 #endif // INCLUDE_ALL_GCS
4194
4195 ALL_JAVA_THREADS(p) {
4196 ResourceMark rm;
4197 p->print_on(st);
4198 if (print_stacks) {
4199 if (internal_format) {
4200 p->trace_stack();
4201 } else {
4202 p->print_stack_on(st);
4203 }
4204 }
4205 st->cr();
4206 #if INCLUDE_ALL_GCS
4207 if (print_concurrent_locks) {
4208 concurrent_locks.print_locks_on(p, st);
4209 }
4210 #endif // INCLUDE_ALL_GCS
4211 }
4212
4213 VMThread::vm_thread()->print_on(st);
4214 st->cr();
4215 Universe::heap()->print_gc_threads_on(st);
4216 WatcherThread* wt = WatcherThread::watcher_thread();
4217 if (wt != NULL) {
4218 wt->print_on(st);
4219 st->cr();
4220 }
4221 CompileBroker::print_compiler_threads_on(st);
4222 st->flush();
4223 }
4224
4225 // Threads::print_on_error() is called by fatal error handler. It's possible
4226 // that VM is not at safepoint and/or current thread is inside signal handler.
4227 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4228 // memory (even in resource area), it might deadlock the error handler.
4229 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4230 int buflen) {
4231 bool found_current = false;
4232 st->print_cr("Java Threads: ( => current thread )");
4233 ALL_JAVA_THREADS(thread) {
4234 bool is_current = (current == thread);
4235 found_current = found_current || is_current;
4236
4237 st->print("%s", is_current ? "=>" : " ");
4238
4239 st->print(PTR_FORMAT, thread);
4240 st->print(" ");
4241 thread->print_on_error(st, buf, buflen);
4242 st->cr();
4243 }
4244 st->cr();
4245
4246 st->print_cr("Other Threads:");
4247 if (VMThread::vm_thread()) {
4248 bool is_current = (current == VMThread::vm_thread());
4249 found_current = found_current || is_current;
4250 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4251
4252 st->print(PTR_FORMAT, VMThread::vm_thread());
4253 st->print(" ");
4254 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4255 st->cr();
4256 }
4257 WatcherThread* wt = WatcherThread::watcher_thread();
4258 if (wt != NULL) {
4259 bool is_current = (current == wt);
4260 found_current = found_current || is_current;
4261 st->print("%s", is_current ? "=>" : " ");
4262
4263 st->print(PTR_FORMAT, wt);
4264 st->print(" ");
4265 wt->print_on_error(st, buf, buflen);
4266 st->cr();
4267 }
4268 if (!found_current) {
4269 st->cr();
4270 st->print("=>" PTR_FORMAT " (exited) ", current);
4271 current->print_on_error(st, buf, buflen);
4272 st->cr();
4273 }
4274 }
4275
4276 // Internal SpinLock and Mutex
4277 // Based on ParkEvent
4278
4279 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4280 //
4281 // We employ SpinLocks _only for low-contention, fixed-length
4282 // short-duration critical sections where we're concerned
4283 // about native mutex_t or HotSpot Mutex:: latency.
4284 // The mux construct provides a spin-then-block mutual exclusion
4285 // mechanism.
4286 //
4287 // Testing has shown that contention on the ListLock guarding gFreeList
4288 // is common. If we implement ListLock as a simple SpinLock it's common
4289 // for the JVM to devolve to yielding with little progress. This is true
4290 // despite the fact that the critical sections protected by ListLock are
4291 // extremely short.
4292 //
4293 // TODO-FIXME: ListLock should be of type SpinLock.
4294 // We should make this a 1st-class type, integrated into the lock
4295 // hierarchy as leaf-locks. Critically, the SpinLock structure
4296 // should have sufficient padding to avoid false-sharing and excessive
4297 // cache-coherency traffic.
4298
4299
4300 typedef volatile int SpinLockT;
4301
4302 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4303 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4304 return; // normal fast-path return
4305 }
4306
4307 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4308 TEVENT(SpinAcquire - ctx);
4309 int ctr = 0;
4310 int Yields = 0;
4311 for (;;) {
4312 while (*adr != 0) {
4313 ++ctr;
4314 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4315 if (Yields > 5) {
4316 os::naked_short_sleep(1);
4317 } else {
4318 os::naked_yield();
4319 ++Yields;
4320 }
4321 } else {
4322 SpinPause();
4323 }
4324 }
4325 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4326 }
4327 }
4328
4329 void Thread::SpinRelease(volatile int * adr) {
4330 assert(*adr != 0, "invariant");
4331 OrderAccess::fence(); // guarantee at least release consistency.
4332 // Roach-motel semantics.
4333 // It's safe if subsequent LDs and STs float "up" into the critical section,
4334 // but prior LDs and STs within the critical section can't be allowed
4335 // to reorder or float past the ST that releases the lock.
4336 // Loads and stores in the critical section - which appear in program
4337 // order before the store that releases the lock - must also appear
4338 // before the store that releases the lock in memory visibility order.
4339 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4340 // the ST of 0 into the lock-word which releases the lock, so fence
4341 // more than covers this on all platforms.
4342 *adr = 0;
4343 }
4344
4345 // muxAcquire and muxRelease:
4346 //
4347 // * muxAcquire and muxRelease support a single-word lock-word construct.
4348 // The LSB of the word is set IFF the lock is held.
4349 // The remainder of the word points to the head of a singly-linked list
4350 // of threads blocked on the lock.
4351 //
4352 // * The current implementation of muxAcquire-muxRelease uses its own
4353 // dedicated Thread._MuxEvent instance. If we're interested in
4354 // minimizing the peak number of extant ParkEvent instances then
4355 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4356 // as certain invariants were satisfied. Specifically, care would need
4357 // to be taken with regards to consuming unpark() "permits".
4358 // A safe rule of thumb is that a thread would never call muxAcquire()
4359 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4360 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4361 // consume an unpark() permit intended for monitorenter, for instance.
4362 // One way around this would be to widen the restricted-range semaphore
4363 // implemented in park(). Another alternative would be to provide
4364 // multiple instances of the PlatformEvent() for each thread. One
4365 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4366 //
4367 // * Usage:
4368 // -- Only as leaf locks
4369 // -- for short-term locking only as muxAcquire does not perform
4370 // thread state transitions.
4371 //
4372 // Alternatives:
4373 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4374 // but with parking or spin-then-park instead of pure spinning.
4375 // * Use Taura-Oyama-Yonenzawa locks.
4376 // * It's possible to construct a 1-0 lock if we encode the lockword as
4377 // (List,LockByte). Acquire will CAS the full lockword while Release
4378 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4379 // acquiring threads use timers (ParkTimed) to detect and recover from
4380 // the stranding window. Thread/Node structures must be aligned on 256-byte
4381 // boundaries by using placement-new.
4382 // * Augment MCS with advisory back-link fields maintained with CAS().
4383 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4384 // The validity of the backlinks must be ratified before we trust the value.
4385 // If the backlinks are invalid the exiting thread must back-track through the
4386 // the forward links, which are always trustworthy.
4387 // * Add a successor indication. The LockWord is currently encoded as
4388 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4389 // to provide the usual futile-wakeup optimization.
4390 // See RTStt for details.
4391 // * Consider schedctl.sc_nopreempt to cover the critical section.
4392 //
4393
4394
4395 typedef volatile intptr_t MutexT; // Mux Lock-word
4396 enum MuxBits { LOCKBIT = 1 };
4397
4398 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4399 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4400 if (w == 0) return;
4401 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4402 return;
4403 }
4404
4405 TEVENT(muxAcquire - Contention);
4406 ParkEvent * const Self = Thread::current()->_MuxEvent;
4407 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4408 for (;;) {
4409 int its = (os::is_MP() ? 100 : 0) + 1;
4410
4411 // Optional spin phase: spin-then-park strategy
4412 while (--its >= 0) {
4413 w = *Lock;
4414 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4415 return;
4416 }
4417 }
4418
4419 Self->reset();
4420 Self->OnList = intptr_t(Lock);
4421 // The following fence() isn't _strictly necessary as the subsequent
4422 // CAS() both serializes execution and ratifies the fetched *Lock value.
4423 OrderAccess::fence();
4424 for (;;) {
4425 w = *Lock;
4426 if ((w & LOCKBIT) == 0) {
4427 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4428 Self->OnList = 0; // hygiene - allows stronger asserts
4429 return;
4430 }
4431 continue; // Interference -- *Lock changed -- Just retry
4432 }
4433 assert(w & LOCKBIT, "invariant");
4434 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4435 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4436 }
4437
4438 while (Self->OnList != 0) {
4439 Self->park();
4440 }
4441 }
4442 }
4443
4444 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4445 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4446 if (w == 0) return;
4447 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4448 return;
4449 }
4450
4451 TEVENT(muxAcquire - Contention);
4452 ParkEvent * ReleaseAfter = NULL;
4453 if (ev == NULL) {
4454 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4455 }
4456 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4457 for (;;) {
4458 guarantee(ev->OnList == 0, "invariant");
4459 int its = (os::is_MP() ? 100 : 0) + 1;
4460
4461 // Optional spin phase: spin-then-park strategy
4462 while (--its >= 0) {
4463 w = *Lock;
4464 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4465 if (ReleaseAfter != NULL) {
4466 ParkEvent::Release(ReleaseAfter);
4467 }
4468 return;
4469 }
4470 }
4471
4472 ev->reset();
4473 ev->OnList = intptr_t(Lock);
4474 // The following fence() isn't _strictly necessary as the subsequent
4475 // CAS() both serializes execution and ratifies the fetched *Lock value.
4476 OrderAccess::fence();
4477 for (;;) {
4478 w = *Lock;
4479 if ((w & LOCKBIT) == 0) {
4480 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4481 ev->OnList = 0;
4482 // We call ::Release while holding the outer lock, thus
4483 // artificially lengthening the critical section.
4484 // Consider deferring the ::Release() until the subsequent unlock(),
4485 // after we've dropped the outer lock.
4486 if (ReleaseAfter != NULL) {
4487 ParkEvent::Release(ReleaseAfter);
4488 }
4489 return;
4490 }
4491 continue; // Interference -- *Lock changed -- Just retry
4492 }
4493 assert(w & LOCKBIT, "invariant");
4494 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4495 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4496 }
4497
4498 while (ev->OnList != 0) {
4499 ev->park();
4500 }
4501 }
4502 }
4503
4504 // Release() must extract a successor from the list and then wake that thread.
4505 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4506 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4507 // Release() would :
4508 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4509 // (B) Extract a successor from the private list "in-hand"
4510 // (C) attempt to CAS() the residual back into *Lock over null.
4511 // If there were any newly arrived threads and the CAS() would fail.
4512 // In that case Release() would detach the RATs, re-merge the list in-hand
4513 // with the RATs and repeat as needed. Alternately, Release() might
4514 // detach and extract a successor, but then pass the residual list to the wakee.
4515 // The wakee would be responsible for reattaching and remerging before it
4516 // competed for the lock.
4517 //
4518 // Both "pop" and DMR are immune from ABA corruption -- there can be
4519 // multiple concurrent pushers, but only one popper or detacher.
4520 // This implementation pops from the head of the list. This is unfair,
4521 // but tends to provide excellent throughput as hot threads remain hot.
4522 // (We wake recently run threads first).
4523 //
4524 // All paths through muxRelease() will execute a CAS.
4525 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4526 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4527 // executed within the critical section are complete and globally visible before the
4528 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4529 void Thread::muxRelease(volatile intptr_t * Lock) {
4530 for (;;) {
4531 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4532 assert(w & LOCKBIT, "invariant");
4533 if (w == LOCKBIT) return;
4534 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4535 assert(List != NULL, "invariant");
4536 assert(List->OnList == intptr_t(Lock), "invariant");
4537 ParkEvent * const nxt = List->ListNext;
4538 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4539
4540 // The following CAS() releases the lock and pops the head element.
4541 // The CAS() also ratifies the previously fetched lock-word value.
4542 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4543 continue;
4544 }
4545 List->OnList = 0;
4546 OrderAccess::fence();
4547 List->unpark();
4548 return;
4549 }
4550 }
4551
4552
4553 void Threads::verify() {
4554 ALL_JAVA_THREADS(p) {
4555 p->verify();
4556 }
4557 VMThread* thread = VMThread::vm_thread();
4558 if (thread != NULL) thread->verify();
4559 }