1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/codeCacheExtensions.hpp"
32 #include "code/scopeDesc.hpp"
33 #include "compiler/compileBroker.hpp"
34 #include "gc/shared/gcId.hpp"
35 #include "gc/shared/gcLocker.inline.hpp"
36 #include "gc/shared/workgroup.hpp"
37 #include "interpreter/interpreter.hpp"
38 #include "interpreter/linkResolver.hpp"
39 #include "interpreter/oopMapCache.hpp"
40 #include "jvmtifiles/jvmtiEnv.hpp"
41 #include "memory/metaspaceShared.hpp"
42 #include "memory/oopFactory.hpp"
43 #include "memory/universe.inline.hpp"
44 #include "oops/instanceKlass.hpp"
45 #include "oops/objArrayOop.hpp"
46 #include "oops/oop.inline.hpp"
47 #include "oops/symbol.hpp"
48 #include "oops/verifyOopClosure.hpp"
49 #include "prims/jvm_misc.hpp"
50 #include "prims/jvmtiExport.hpp"
51 #include "prims/jvmtiThreadState.hpp"
52 #include "prims/privilegedStack.hpp"
53 #include "runtime/arguments.hpp"
54 #include "runtime/atomic.inline.hpp"
55 #include "runtime/biasedLocking.hpp"
56 #include "runtime/commandLineFlagConstraintList.hpp"
57 #include "runtime/commandLineFlagRangeList.hpp"
58 #include "runtime/deoptimization.hpp"
59 #include "runtime/fprofiler.hpp"
60 #include "runtime/frame.inline.hpp"
61 #include "runtime/globals.hpp"
62 #include "runtime/init.hpp"
63 #include "runtime/interfaceSupport.hpp"
64 #include "runtime/java.hpp"
65 #include "runtime/javaCalls.hpp"
66 #include "runtime/jniPeriodicChecker.hpp"
67 #include "runtime/memprofiler.hpp"
68 #include "runtime/mutexLocker.hpp"
69 #include "runtime/objectMonitor.hpp"
70 #include "runtime/orderAccess.inline.hpp"
71 #include "runtime/osThread.hpp"
72 #include "runtime/safepoint.hpp"
73 #include "runtime/sharedRuntime.hpp"
74 #include "runtime/statSampler.hpp"
75 #include "runtime/stubRoutines.hpp"
76 #include "runtime/sweeper.hpp"
77 #include "runtime/task.hpp"
78 #include "runtime/thread.inline.hpp"
79 #include "runtime/threadCritical.hpp"
80 #include "runtime/threadLocalStorage.hpp"
81 #include "runtime/vframe.hpp"
82 #include "runtime/vframeArray.hpp"
83 #include "runtime/vframe_hp.hpp"
84 #include "runtime/vmThread.hpp"
85 #include "runtime/vm_operations.hpp"
86 #include "runtime/vm_version.hpp"
87 #include "services/attachListener.hpp"
88 #include "services/management.hpp"
89 #include "services/memTracker.hpp"
90 #include "services/threadService.hpp"
91 #include "trace/traceMacros.hpp"
92 #include "trace/tracing.hpp"
93 #include "utilities/defaultStream.hpp"
94 #include "utilities/dtrace.hpp"
95 #include "utilities/events.hpp"
96 #include "utilities/macros.hpp"
97 #include "utilities/preserveException.hpp"
98 #if INCLUDE_ALL_GCS
99 #include "gc/cms/concurrentMarkSweepThread.hpp"
100 #include "gc/g1/concurrentMarkThread.inline.hpp"
101 #include "gc/parallel/pcTasks.hpp"
102 #endif // INCLUDE_ALL_GCS
103 #ifdef COMPILER1
104 #include "c1/c1_Compiler.hpp"
105 #endif
106 #ifdef COMPILER2
107 #include "opto/c2compiler.hpp"
108 #include "opto/idealGraphPrinter.hpp"
109 #endif
110 #if INCLUDE_RTM_OPT
111 #include "runtime/rtmLocking.hpp"
112 #endif
113
114 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
115
116 #ifdef DTRACE_ENABLED
117
118 // Only bother with this argument setup if dtrace is available
119
120 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
121 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
122
123 #define DTRACE_THREAD_PROBE(probe, javathread) \
124 { \
125 ResourceMark rm(this); \
126 int len = 0; \
127 const char* name = (javathread)->get_thread_name(); \
128 len = strlen(name); \
129 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
130 (char *) name, len, \
131 java_lang_Thread::thread_id((javathread)->threadObj()), \
132 (uintptr_t) (javathread)->osthread()->thread_id(), \
133 java_lang_Thread::is_daemon((javathread)->threadObj())); \
134 }
135
136 #else // ndef DTRACE_ENABLED
137
138 #define DTRACE_THREAD_PROBE(probe, javathread)
139
140 #endif // ndef DTRACE_ENABLED
141
142
143 // Class hierarchy
144 // - Thread
145 // - VMThread
146 // - WatcherThread
147 // - ConcurrentMarkSweepThread
148 // - JavaThread
149 // - CompilerThread
150
151 // ======= Thread ========
152 // Support for forcing alignment of thread objects for biased locking
153 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
154 if (UseBiasedLocking) {
155 const int alignment = markOopDesc::biased_lock_alignment;
156 size_t aligned_size = size + (alignment - sizeof(intptr_t));
157 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
158 : AllocateHeap(aligned_size, flags, CURRENT_PC,
159 AllocFailStrategy::RETURN_NULL);
160 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
161 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
162 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
163 "JavaThread alignment code overflowed allocated storage");
164 if (TraceBiasedLocking) {
165 if (aligned_addr != real_malloc_addr) {
166 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
167 real_malloc_addr, aligned_addr);
168 }
169 }
170 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
171 return aligned_addr;
172 } else {
173 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
174 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
175 }
176 }
177
178 void Thread::operator delete(void* p) {
179 if (UseBiasedLocking) {
180 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
181 FreeHeap(real_malloc_addr);
182 } else {
183 FreeHeap(p);
184 }
185 }
186
187
188 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
189 // JavaThread
190
191
192 Thread::Thread() {
193 // stack and get_thread
194 set_stack_base(NULL);
195 set_stack_size(0);
196 set_self_raw_id(0);
197 set_lgrp_id(-1);
198 DEBUG_ONLY(clear_suspendible_thread();)
199
200 // allocated data structures
201 set_osthread(NULL);
202 set_resource_area(new (mtThread)ResourceArea());
203 DEBUG_ONLY(_current_resource_mark = NULL;)
204 set_handle_area(new (mtThread) HandleArea(NULL));
205 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
206 set_active_handles(NULL);
207 set_free_handle_block(NULL);
208 set_last_handle_mark(NULL);
209
210 // This initial value ==> never claimed.
211 _oops_do_parity = 0;
212
213 // the handle mark links itself to last_handle_mark
214 new HandleMark(this);
215
216 // plain initialization
217 debug_only(_owned_locks = NULL;)
218 debug_only(_allow_allocation_count = 0;)
219 NOT_PRODUCT(_allow_safepoint_count = 0;)
220 NOT_PRODUCT(_skip_gcalot = false;)
221 _jvmti_env_iteration_count = 0;
222 set_allocated_bytes(0);
223 _gc_id = GCId::undefined();
224 _vm_operation_started_count = 0;
225 _vm_operation_completed_count = 0;
226 _current_pending_monitor = NULL;
227 _current_pending_monitor_is_from_java = true;
228 _current_waiting_monitor = NULL;
229 _num_nested_signal = 0;
230 omFreeList = NULL;
231 omFreeCount = 0;
232 omFreeProvision = 32;
233 omInUseList = NULL;
234 omInUseCount = 0;
235
236 #ifdef ASSERT
237 _visited_for_critical_count = false;
238 #endif
239
240 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
241 Monitor::_safepoint_check_sometimes);
242 _suspend_flags = 0;
243
244 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
245 _hashStateX = os::random();
246 _hashStateY = 842502087;
247 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
248 _hashStateW = 273326509;
249
250 _OnTrap = 0;
251 _schedctl = NULL;
252 _Stalled = 0;
253 _TypeTag = 0x2BAD;
254
255 // Many of the following fields are effectively final - immutable
256 // Note that nascent threads can't use the Native Monitor-Mutex
257 // construct until the _MutexEvent is initialized ...
258 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
259 // we might instead use a stack of ParkEvents that we could provision on-demand.
260 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
261 // and ::Release()
262 _ParkEvent = ParkEvent::Allocate(this);
263 _SleepEvent = ParkEvent::Allocate(this);
264 _MutexEvent = ParkEvent::Allocate(this);
265 _MuxEvent = ParkEvent::Allocate(this);
266
267 #ifdef CHECK_UNHANDLED_OOPS
268 if (CheckUnhandledOops) {
269 _unhandled_oops = new UnhandledOops(this);
270 }
271 #endif // CHECK_UNHANDLED_OOPS
272 #ifdef ASSERT
273 if (UseBiasedLocking) {
274 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
275 assert(this == _real_malloc_address ||
276 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
277 "bug in forced alignment of thread objects");
278 }
279 #endif // ASSERT
280 }
281
282 // Non-inlined version to be used where thread.inline.hpp shouldn't be included.
283 Thread* Thread::current_noinline() {
284 return Thread::current();
285 }
286
287 void Thread::initialize_thread_local_storage() {
288 // Note: Make sure this method only calls
289 // non-blocking operations. Otherwise, it might not work
290 // with the thread-startup/safepoint interaction.
291
292 // During Java thread startup, safepoint code should allow this
293 // method to complete because it may need to allocate memory to
294 // store information for the new thread.
295
296 // initialize structure dependent on thread local storage
297 ThreadLocalStorage::set_thread(this);
298 }
299
300 void Thread::record_stack_base_and_size() {
301 set_stack_base(os::current_stack_base());
302 set_stack_size(os::current_stack_size());
303 if (is_Java_thread()) {
304 ((JavaThread*) this)->set_stack_overflow_limit();
305 }
306 // CR 7190089: on Solaris, primordial thread's stack is adjusted
307 // in initialize_thread(). Without the adjustment, stack size is
308 // incorrect if stack is set to unlimited (ulimit -s unlimited).
309 // So far, only Solaris has real implementation of initialize_thread().
310 //
311 // set up any platform-specific state.
312 os::initialize_thread(this);
313
314 #if INCLUDE_NMT
315 // record thread's native stack, stack grows downward
316 address stack_low_addr = stack_base() - stack_size();
317 MemTracker::record_thread_stack(stack_low_addr, stack_size());
318 #endif // INCLUDE_NMT
319 }
320
321
322 Thread::~Thread() {
323 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
324 ObjectSynchronizer::omFlush(this);
325
326 EVENT_THREAD_DESTRUCT(this);
327
328 // stack_base can be NULL if the thread is never started or exited before
329 // record_stack_base_and_size called. Although, we would like to ensure
330 // that all started threads do call record_stack_base_and_size(), there is
331 // not proper way to enforce that.
332 #if INCLUDE_NMT
333 if (_stack_base != NULL) {
334 address low_stack_addr = stack_base() - stack_size();
335 MemTracker::release_thread_stack(low_stack_addr, stack_size());
336 #ifdef ASSERT
337 set_stack_base(NULL);
338 #endif
339 }
340 #endif // INCLUDE_NMT
341
342 // deallocate data structures
343 delete resource_area();
344 // since the handle marks are using the handle area, we have to deallocated the root
345 // handle mark before deallocating the thread's handle area,
346 assert(last_handle_mark() != NULL, "check we have an element");
347 delete last_handle_mark();
348 assert(last_handle_mark() == NULL, "check we have reached the end");
349
350 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
351 // We NULL out the fields for good hygiene.
352 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
353 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
354 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
355 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
356
357 delete handle_area();
358 delete metadata_handles();
359
360 // osthread() can be NULL, if creation of thread failed.
361 if (osthread() != NULL) os::free_thread(osthread());
362
363 delete _SR_lock;
364
365 // clear thread local storage if the Thread is deleting itself
366 if (this == Thread::current()) {
367 ThreadLocalStorage::set_thread(NULL);
368 } else {
369 // In the case where we're not the current thread, invalidate all the
370 // caches in case some code tries to get the current thread or the
371 // thread that was destroyed, and gets stale information.
372 ThreadLocalStorage::invalidate_all();
373 }
374 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
375 }
376
377 // NOTE: dummy function for assertion purpose.
378 void Thread::run() {
379 ShouldNotReachHere();
380 }
381
382 #ifdef ASSERT
383 // Private method to check for dangling thread pointer
384 void check_for_dangling_thread_pointer(Thread *thread) {
385 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
386 "possibility of dangling Thread pointer");
387 }
388 #endif
389
390 ThreadPriority Thread::get_priority(const Thread* const thread) {
391 ThreadPriority priority;
392 // Can return an error!
393 (void)os::get_priority(thread, priority);
394 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
395 return priority;
396 }
397
398 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
399 debug_only(check_for_dangling_thread_pointer(thread);)
400 // Can return an error!
401 (void)os::set_priority(thread, priority);
402 }
403
404
405 void Thread::start(Thread* thread) {
406 // Start is different from resume in that its safety is guaranteed by context or
407 // being called from a Java method synchronized on the Thread object.
408 if (!DisableStartThread) {
409 if (thread->is_Java_thread()) {
410 // Initialize the thread state to RUNNABLE before starting this thread.
411 // Can not set it after the thread started because we do not know the
412 // exact thread state at that time. It could be in MONITOR_WAIT or
413 // in SLEEPING or some other state.
414 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
415 java_lang_Thread::RUNNABLE);
416 }
417 os::start_thread(thread);
418 }
419 }
420
421 // Enqueue a VM_Operation to do the job for us - sometime later
422 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
423 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
424 VMThread::execute(vm_stop);
425 }
426
427
428 // Check if an external suspend request has completed (or has been
429 // cancelled). Returns true if the thread is externally suspended and
430 // false otherwise.
431 //
432 // The bits parameter returns information about the code path through
433 // the routine. Useful for debugging:
434 //
435 // set in is_ext_suspend_completed():
436 // 0x00000001 - routine was entered
437 // 0x00000010 - routine return false at end
438 // 0x00000100 - thread exited (return false)
439 // 0x00000200 - suspend request cancelled (return false)
440 // 0x00000400 - thread suspended (return true)
441 // 0x00001000 - thread is in a suspend equivalent state (return true)
442 // 0x00002000 - thread is native and walkable (return true)
443 // 0x00004000 - thread is native_trans and walkable (needed retry)
444 //
445 // set in wait_for_ext_suspend_completion():
446 // 0x00010000 - routine was entered
447 // 0x00020000 - suspend request cancelled before loop (return false)
448 // 0x00040000 - thread suspended before loop (return true)
449 // 0x00080000 - suspend request cancelled in loop (return false)
450 // 0x00100000 - thread suspended in loop (return true)
451 // 0x00200000 - suspend not completed during retry loop (return false)
452
453 // Helper class for tracing suspend wait debug bits.
454 //
455 // 0x00000100 indicates that the target thread exited before it could
456 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
457 // 0x00080000 each indicate a cancelled suspend request so they don't
458 // count as wait failures either.
459 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
460
461 class TraceSuspendDebugBits : public StackObj {
462 private:
463 JavaThread * jt;
464 bool is_wait;
465 bool called_by_wait; // meaningful when !is_wait
466 uint32_t * bits;
467
468 public:
469 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
470 uint32_t *_bits) {
471 jt = _jt;
472 is_wait = _is_wait;
473 called_by_wait = _called_by_wait;
474 bits = _bits;
475 }
476
477 ~TraceSuspendDebugBits() {
478 if (!is_wait) {
479 #if 1
480 // By default, don't trace bits for is_ext_suspend_completed() calls.
481 // That trace is very chatty.
482 return;
483 #else
484 if (!called_by_wait) {
485 // If tracing for is_ext_suspend_completed() is enabled, then only
486 // trace calls to it from wait_for_ext_suspend_completion()
487 return;
488 }
489 #endif
490 }
491
492 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
493 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
494 MutexLocker ml(Threads_lock); // needed for get_thread_name()
495 ResourceMark rm;
496
497 tty->print_cr(
498 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
499 jt->get_thread_name(), *bits);
500
501 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
502 }
503 }
504 }
505 };
506 #undef DEBUG_FALSE_BITS
507
508
509 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
510 uint32_t *bits) {
511 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
512
513 bool did_trans_retry = false; // only do thread_in_native_trans retry once
514 bool do_trans_retry; // flag to force the retry
515
516 *bits |= 0x00000001;
517
518 do {
519 do_trans_retry = false;
520
521 if (is_exiting()) {
522 // Thread is in the process of exiting. This is always checked
523 // first to reduce the risk of dereferencing a freed JavaThread.
524 *bits |= 0x00000100;
525 return false;
526 }
527
528 if (!is_external_suspend()) {
529 // Suspend request is cancelled. This is always checked before
530 // is_ext_suspended() to reduce the risk of a rogue resume
531 // confusing the thread that made the suspend request.
532 *bits |= 0x00000200;
533 return false;
534 }
535
536 if (is_ext_suspended()) {
537 // thread is suspended
538 *bits |= 0x00000400;
539 return true;
540 }
541
542 // Now that we no longer do hard suspends of threads running
543 // native code, the target thread can be changing thread state
544 // while we are in this routine:
545 //
546 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
547 //
548 // We save a copy of the thread state as observed at this moment
549 // and make our decision about suspend completeness based on the
550 // copy. This closes the race where the thread state is seen as
551 // _thread_in_native_trans in the if-thread_blocked check, but is
552 // seen as _thread_blocked in if-thread_in_native_trans check.
553 JavaThreadState save_state = thread_state();
554
555 if (save_state == _thread_blocked && is_suspend_equivalent()) {
556 // If the thread's state is _thread_blocked and this blocking
557 // condition is known to be equivalent to a suspend, then we can
558 // consider the thread to be externally suspended. This means that
559 // the code that sets _thread_blocked has been modified to do
560 // self-suspension if the blocking condition releases. We also
561 // used to check for CONDVAR_WAIT here, but that is now covered by
562 // the _thread_blocked with self-suspension check.
563 //
564 // Return true since we wouldn't be here unless there was still an
565 // external suspend request.
566 *bits |= 0x00001000;
567 return true;
568 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
569 // Threads running native code will self-suspend on native==>VM/Java
570 // transitions. If its stack is walkable (should always be the case
571 // unless this function is called before the actual java_suspend()
572 // call), then the wait is done.
573 *bits |= 0x00002000;
574 return true;
575 } else if (!called_by_wait && !did_trans_retry &&
576 save_state == _thread_in_native_trans &&
577 frame_anchor()->walkable()) {
578 // The thread is transitioning from thread_in_native to another
579 // thread state. check_safepoint_and_suspend_for_native_trans()
580 // will force the thread to self-suspend. If it hasn't gotten
581 // there yet we may have caught the thread in-between the native
582 // code check above and the self-suspend. Lucky us. If we were
583 // called by wait_for_ext_suspend_completion(), then it
584 // will be doing the retries so we don't have to.
585 //
586 // Since we use the saved thread state in the if-statement above,
587 // there is a chance that the thread has already transitioned to
588 // _thread_blocked by the time we get here. In that case, we will
589 // make a single unnecessary pass through the logic below. This
590 // doesn't hurt anything since we still do the trans retry.
591
592 *bits |= 0x00004000;
593
594 // Once the thread leaves thread_in_native_trans for another
595 // thread state, we break out of this retry loop. We shouldn't
596 // need this flag to prevent us from getting back here, but
597 // sometimes paranoia is good.
598 did_trans_retry = true;
599
600 // We wait for the thread to transition to a more usable state.
601 for (int i = 1; i <= SuspendRetryCount; i++) {
602 // We used to do an "os::yield_all(i)" call here with the intention
603 // that yielding would increase on each retry. However, the parameter
604 // is ignored on Linux which means the yield didn't scale up. Waiting
605 // on the SR_lock below provides a much more predictable scale up for
606 // the delay. It also provides a simple/direct point to check for any
607 // safepoint requests from the VMThread
608
609 // temporarily drops SR_lock while doing wait with safepoint check
610 // (if we're a JavaThread - the WatcherThread can also call this)
611 // and increase delay with each retry
612 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
613
614 // check the actual thread state instead of what we saved above
615 if (thread_state() != _thread_in_native_trans) {
616 // the thread has transitioned to another thread state so
617 // try all the checks (except this one) one more time.
618 do_trans_retry = true;
619 break;
620 }
621 } // end retry loop
622
623
624 }
625 } while (do_trans_retry);
626
627 *bits |= 0x00000010;
628 return false;
629 }
630
631 // Wait for an external suspend request to complete (or be cancelled).
632 // Returns true if the thread is externally suspended and false otherwise.
633 //
634 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
635 uint32_t *bits) {
636 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
637 false /* !called_by_wait */, bits);
638
639 // local flag copies to minimize SR_lock hold time
640 bool is_suspended;
641 bool pending;
642 uint32_t reset_bits;
643
644 // set a marker so is_ext_suspend_completed() knows we are the caller
645 *bits |= 0x00010000;
646
647 // We use reset_bits to reinitialize the bits value at the top of
648 // each retry loop. This allows the caller to make use of any
649 // unused bits for their own marking purposes.
650 reset_bits = *bits;
651
652 {
653 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
654 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
655 delay, bits);
656 pending = is_external_suspend();
657 }
658 // must release SR_lock to allow suspension to complete
659
660 if (!pending) {
661 // A cancelled suspend request is the only false return from
662 // is_ext_suspend_completed() that keeps us from entering the
663 // retry loop.
664 *bits |= 0x00020000;
665 return false;
666 }
667
668 if (is_suspended) {
669 *bits |= 0x00040000;
670 return true;
671 }
672
673 for (int i = 1; i <= retries; i++) {
674 *bits = reset_bits; // reinit to only track last retry
675
676 // We used to do an "os::yield_all(i)" call here with the intention
677 // that yielding would increase on each retry. However, the parameter
678 // is ignored on Linux which means the yield didn't scale up. Waiting
679 // on the SR_lock below provides a much more predictable scale up for
680 // the delay. It also provides a simple/direct point to check for any
681 // safepoint requests from the VMThread
682
683 {
684 MutexLocker ml(SR_lock());
685 // wait with safepoint check (if we're a JavaThread - the WatcherThread
686 // can also call this) and increase delay with each retry
687 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
688
689 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
690 delay, bits);
691
692 // It is possible for the external suspend request to be cancelled
693 // (by a resume) before the actual suspend operation is completed.
694 // Refresh our local copy to see if we still need to wait.
695 pending = is_external_suspend();
696 }
697
698 if (!pending) {
699 // A cancelled suspend request is the only false return from
700 // is_ext_suspend_completed() that keeps us from staying in the
701 // retry loop.
702 *bits |= 0x00080000;
703 return false;
704 }
705
706 if (is_suspended) {
707 *bits |= 0x00100000;
708 return true;
709 }
710 } // end retry loop
711
712 // thread did not suspend after all our retries
713 *bits |= 0x00200000;
714 return false;
715 }
716
717 #ifndef PRODUCT
718 void JavaThread::record_jump(address target, address instr, const char* file,
719 int line) {
720
721 // This should not need to be atomic as the only way for simultaneous
722 // updates is via interrupts. Even then this should be rare or non-existent
723 // and we don't care that much anyway.
724
725 int index = _jmp_ring_index;
726 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
727 _jmp_ring[index]._target = (intptr_t) target;
728 _jmp_ring[index]._instruction = (intptr_t) instr;
729 _jmp_ring[index]._file = file;
730 _jmp_ring[index]._line = line;
731 }
732 #endif // PRODUCT
733
734 // Called by flat profiler
735 // Callers have already called wait_for_ext_suspend_completion
736 // The assertion for that is currently too complex to put here:
737 bool JavaThread::profile_last_Java_frame(frame* _fr) {
738 bool gotframe = false;
739 // self suspension saves needed state.
740 if (has_last_Java_frame() && _anchor.walkable()) {
741 *_fr = pd_last_frame();
742 gotframe = true;
743 }
744 return gotframe;
745 }
746
747 void Thread::interrupt(Thread* thread) {
748 debug_only(check_for_dangling_thread_pointer(thread);)
749 os::interrupt(thread);
750 }
751
752 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
753 debug_only(check_for_dangling_thread_pointer(thread);)
754 // Note: If clear_interrupted==false, this simply fetches and
755 // returns the value of the field osthread()->interrupted().
756 return os::is_interrupted(thread, clear_interrupted);
757 }
758
759
760 // GC Support
761 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
762 jint thread_parity = _oops_do_parity;
763 if (thread_parity != strong_roots_parity) {
764 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
765 if (res == thread_parity) {
766 return true;
767 } else {
768 guarantee(res == strong_roots_parity, "Or else what?");
769 return false;
770 }
771 }
772 return false;
773 }
774
775 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
776 active_handles()->oops_do(f);
777 // Do oop for ThreadShadow
778 f->do_oop((oop*)&_pending_exception);
779 handle_area()->oops_do(f);
780 }
781
782 void Thread::nmethods_do(CodeBlobClosure* cf) {
783 // no nmethods in a generic thread...
784 }
785
786 void Thread::metadata_handles_do(void f(Metadata*)) {
787 // Only walk the Handles in Thread.
788 if (metadata_handles() != NULL) {
789 for (int i = 0; i< metadata_handles()->length(); i++) {
790 f(metadata_handles()->at(i));
791 }
792 }
793 }
794
795 void Thread::print_on(outputStream* st) const {
796 // get_priority assumes osthread initialized
797 if (osthread() != NULL) {
798 int os_prio;
799 if (os::get_native_priority(this, &os_prio) == OS_OK) {
800 st->print("os_prio=%d ", os_prio);
801 }
802 st->print("tid=" INTPTR_FORMAT " ", this);
803 ext().print_on(st);
804 osthread()->print_on(st);
805 }
806 debug_only(if (WizardMode) print_owned_locks_on(st);)
807 }
808
809 // Thread::print_on_error() is called by fatal error handler. Don't use
810 // any lock or allocate memory.
811 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
812 if (is_VM_thread()) st->print("VMThread");
813 else if (is_Compiler_thread()) st->print("CompilerThread");
814 else if (is_Java_thread()) st->print("JavaThread");
815 else if (is_GC_task_thread()) st->print("GCTaskThread");
816 else if (is_Watcher_thread()) st->print("WatcherThread");
817 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
818 else st->print("Thread");
819
820 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
821 _stack_base - _stack_size, _stack_base);
822
823 if (osthread()) {
824 st->print(" [id=%d]", osthread()->thread_id());
825 }
826 }
827
828 #ifdef ASSERT
829 void Thread::print_owned_locks_on(outputStream* st) const {
830 Monitor *cur = _owned_locks;
831 if (cur == NULL) {
832 st->print(" (no locks) ");
833 } else {
834 st->print_cr(" Locks owned:");
835 while (cur) {
836 cur->print_on(st);
837 cur = cur->next();
838 }
839 }
840 }
841
842 static int ref_use_count = 0;
843
844 bool Thread::owns_locks_but_compiled_lock() const {
845 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
846 if (cur != Compile_lock) return true;
847 }
848 return false;
849 }
850
851
852 #endif
853
854 #ifndef PRODUCT
855
856 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
857 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
858 // no threads which allow_vm_block's are held
859 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
860 // Check if current thread is allowed to block at a safepoint
861 if (!(_allow_safepoint_count == 0)) {
862 fatal("Possible safepoint reached by thread that does not allow it");
863 }
864 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
865 fatal("LEAF method calling lock?");
866 }
867
868 #ifdef ASSERT
869 if (potential_vm_operation && is_Java_thread()
870 && !Universe::is_bootstrapping()) {
871 // Make sure we do not hold any locks that the VM thread also uses.
872 // This could potentially lead to deadlocks
873 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
874 // Threads_lock is special, since the safepoint synchronization will not start before this is
875 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
876 // since it is used to transfer control between JavaThreads and the VMThread
877 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
878 if ((cur->allow_vm_block() &&
879 cur != Threads_lock &&
880 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
881 cur != VMOperationRequest_lock &&
882 cur != VMOperationQueue_lock) ||
883 cur->rank() == Mutex::special) {
884 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
885 }
886 }
887 }
888
889 if (GCALotAtAllSafepoints) {
890 // We could enter a safepoint here and thus have a gc
891 InterfaceSupport::check_gc_alot();
892 }
893 #endif
894 }
895 #endif
896
897 bool Thread::is_in_stack(address adr) const {
898 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
899 address end = os::current_stack_pointer();
900 // Allow non Java threads to call this without stack_base
901 if (_stack_base == NULL) return true;
902 if (stack_base() >= adr && adr >= end) return true;
903
904 return false;
905 }
906
907
908 bool Thread::is_in_usable_stack(address adr) const {
909 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
910 size_t usable_stack_size = _stack_size - stack_guard_size;
911
912 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
913 }
914
915
916 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
917 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
918 // used for compilation in the future. If that change is made, the need for these methods
919 // should be revisited, and they should be removed if possible.
920
921 bool Thread::is_lock_owned(address adr) const {
922 return on_local_stack(adr);
923 }
924
925 bool Thread::set_as_starting_thread() {
926 // NOTE: this must be called inside the main thread.
927 return os::create_main_thread((JavaThread*)this);
928 }
929
930 static void initialize_class(Symbol* class_name, TRAPS) {
931 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
932 InstanceKlass::cast(klass)->initialize(CHECK);
933 }
934
935
936 // Creates the initial ThreadGroup
937 static Handle create_initial_thread_group(TRAPS) {
938 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
939 instanceKlassHandle klass (THREAD, k);
940
941 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
942 {
943 JavaValue result(T_VOID);
944 JavaCalls::call_special(&result,
945 system_instance,
946 klass,
947 vmSymbols::object_initializer_name(),
948 vmSymbols::void_method_signature(),
949 CHECK_NH);
950 }
951 Universe::set_system_thread_group(system_instance());
952
953 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
954 {
955 JavaValue result(T_VOID);
956 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
957 JavaCalls::call_special(&result,
958 main_instance,
959 klass,
960 vmSymbols::object_initializer_name(),
961 vmSymbols::threadgroup_string_void_signature(),
962 system_instance,
963 string,
964 CHECK_NH);
965 }
966 return main_instance;
967 }
968
969 // Creates the initial Thread
970 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
971 TRAPS) {
972 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
973 instanceKlassHandle klass (THREAD, k);
974 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
975
976 java_lang_Thread::set_thread(thread_oop(), thread);
977 java_lang_Thread::set_priority(thread_oop(), NormPriority);
978 thread->set_threadObj(thread_oop());
979
980 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
981
982 JavaValue result(T_VOID);
983 JavaCalls::call_special(&result, thread_oop,
984 klass,
985 vmSymbols::object_initializer_name(),
986 vmSymbols::threadgroup_string_void_signature(),
987 thread_group,
988 string,
989 CHECK_NULL);
990 return thread_oop();
991 }
992
993 static void call_initializeSystemClass(TRAPS) {
994 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
995 instanceKlassHandle klass (THREAD, k);
996
997 JavaValue result(T_VOID);
998 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
999 vmSymbols::void_method_signature(), CHECK);
1000 }
1001
1002 char java_runtime_name[128] = "";
1003 char java_runtime_version[128] = "";
1004
1005 // extract the JRE name from sun.misc.Version.java_runtime_name
1006 static const char* get_java_runtime_name(TRAPS) {
1007 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1008 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1009 fieldDescriptor fd;
1010 bool found = k != NULL &&
1011 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1012 vmSymbols::string_signature(), &fd);
1013 if (found) {
1014 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1015 if (name_oop == NULL) {
1016 return NULL;
1017 }
1018 const char* name = java_lang_String::as_utf8_string(name_oop,
1019 java_runtime_name,
1020 sizeof(java_runtime_name));
1021 return name;
1022 } else {
1023 return NULL;
1024 }
1025 }
1026
1027 // extract the JRE version from sun.misc.Version.java_runtime_version
1028 static const char* get_java_runtime_version(TRAPS) {
1029 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1030 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1031 fieldDescriptor fd;
1032 bool found = k != NULL &&
1033 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1034 vmSymbols::string_signature(), &fd);
1035 if (found) {
1036 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1037 if (name_oop == NULL) {
1038 return NULL;
1039 }
1040 const char* name = java_lang_String::as_utf8_string(name_oop,
1041 java_runtime_version,
1042 sizeof(java_runtime_version));
1043 return name;
1044 } else {
1045 return NULL;
1046 }
1047 }
1048
1049 // General purpose hook into Java code, run once when the VM is initialized.
1050 // The Java library method itself may be changed independently from the VM.
1051 static void call_postVMInitHook(TRAPS) {
1052 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1053 instanceKlassHandle klass (THREAD, k);
1054 if (klass.not_null()) {
1055 JavaValue result(T_VOID);
1056 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1057 vmSymbols::void_method_signature(),
1058 CHECK);
1059 }
1060 }
1061
1062 static void reset_vm_info_property(TRAPS) {
1063 // the vm info string
1064 ResourceMark rm(THREAD);
1065 const char *vm_info = VM_Version::vm_info_string();
1066
1067 // java.lang.System class
1068 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1069 instanceKlassHandle klass (THREAD, k);
1070
1071 // setProperty arguments
1072 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1073 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1074
1075 // return value
1076 JavaValue r(T_OBJECT);
1077
1078 // public static String setProperty(String key, String value);
1079 JavaCalls::call_static(&r,
1080 klass,
1081 vmSymbols::setProperty_name(),
1082 vmSymbols::string_string_string_signature(),
1083 key_str,
1084 value_str,
1085 CHECK);
1086 }
1087
1088
1089 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1090 bool daemon, TRAPS) {
1091 assert(thread_group.not_null(), "thread group should be specified");
1092 assert(threadObj() == NULL, "should only create Java thread object once");
1093
1094 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1095 instanceKlassHandle klass (THREAD, k);
1096 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1097
1098 java_lang_Thread::set_thread(thread_oop(), this);
1099 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1100 set_threadObj(thread_oop());
1101
1102 JavaValue result(T_VOID);
1103 if (thread_name != NULL) {
1104 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1105 // Thread gets assigned specified name and null target
1106 JavaCalls::call_special(&result,
1107 thread_oop,
1108 klass,
1109 vmSymbols::object_initializer_name(),
1110 vmSymbols::threadgroup_string_void_signature(),
1111 thread_group, // Argument 1
1112 name, // Argument 2
1113 THREAD);
1114 } else {
1115 // Thread gets assigned name "Thread-nnn" and null target
1116 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1117 JavaCalls::call_special(&result,
1118 thread_oop,
1119 klass,
1120 vmSymbols::object_initializer_name(),
1121 vmSymbols::threadgroup_runnable_void_signature(),
1122 thread_group, // Argument 1
1123 Handle(), // Argument 2
1124 THREAD);
1125 }
1126
1127
1128 if (daemon) {
1129 java_lang_Thread::set_daemon(thread_oop());
1130 }
1131
1132 if (HAS_PENDING_EXCEPTION) {
1133 return;
1134 }
1135
1136 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1137 Handle threadObj(THREAD, this->threadObj());
1138
1139 JavaCalls::call_special(&result,
1140 thread_group,
1141 group,
1142 vmSymbols::add_method_name(),
1143 vmSymbols::thread_void_signature(),
1144 threadObj, // Arg 1
1145 THREAD);
1146 }
1147
1148 // NamedThread -- non-JavaThread subclasses with multiple
1149 // uniquely named instances should derive from this.
1150 NamedThread::NamedThread() : Thread() {
1151 _name = NULL;
1152 _processed_thread = NULL;
1153 }
1154
1155 NamedThread::~NamedThread() {
1156 if (_name != NULL) {
1157 FREE_C_HEAP_ARRAY(char, _name);
1158 _name = NULL;
1159 }
1160 }
1161
1162 void NamedThread::set_name(const char* format, ...) {
1163 guarantee(_name == NULL, "Only get to set name once.");
1164 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1165 guarantee(_name != NULL, "alloc failure");
1166 va_list ap;
1167 va_start(ap, format);
1168 jio_vsnprintf(_name, max_name_len, format, ap);
1169 va_end(ap);
1170 }
1171
1172 void NamedThread::initialize_named_thread() {
1173 set_native_thread_name(name());
1174 }
1175
1176 void NamedThread::print_on(outputStream* st) const {
1177 st->print("\"%s\" ", name());
1178 Thread::print_on(st);
1179 st->cr();
1180 }
1181
1182
1183 // ======= WatcherThread ========
1184
1185 // The watcher thread exists to simulate timer interrupts. It should
1186 // be replaced by an abstraction over whatever native support for
1187 // timer interrupts exists on the platform.
1188
1189 WatcherThread* WatcherThread::_watcher_thread = NULL;
1190 bool WatcherThread::_startable = false;
1191 volatile bool WatcherThread::_should_terminate = false;
1192
1193 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1194 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1195 if (os::create_thread(this, os::watcher_thread)) {
1196 _watcher_thread = this;
1197
1198 // Set the watcher thread to the highest OS priority which should not be
1199 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1200 // is created. The only normal thread using this priority is the reference
1201 // handler thread, which runs for very short intervals only.
1202 // If the VMThread's priority is not lower than the WatcherThread profiling
1203 // will be inaccurate.
1204 os::set_priority(this, MaxPriority);
1205 if (!DisableStartThread) {
1206 os::start_thread(this);
1207 }
1208 }
1209 }
1210
1211 int WatcherThread::sleep() const {
1212 // The WatcherThread does not participate in the safepoint protocol
1213 // for the PeriodicTask_lock because it is not a JavaThread.
1214 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1215
1216 if (_should_terminate) {
1217 // check for termination before we do any housekeeping or wait
1218 return 0; // we did not sleep.
1219 }
1220
1221 // remaining will be zero if there are no tasks,
1222 // causing the WatcherThread to sleep until a task is
1223 // enrolled
1224 int remaining = PeriodicTask::time_to_wait();
1225 int time_slept = 0;
1226
1227 // we expect this to timeout - we only ever get unparked when
1228 // we should terminate or when a new task has been enrolled
1229 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1230
1231 jlong time_before_loop = os::javaTimeNanos();
1232
1233 while (true) {
1234 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1235 remaining);
1236 jlong now = os::javaTimeNanos();
1237
1238 if (remaining == 0) {
1239 // if we didn't have any tasks we could have waited for a long time
1240 // consider the time_slept zero and reset time_before_loop
1241 time_slept = 0;
1242 time_before_loop = now;
1243 } else {
1244 // need to recalculate since we might have new tasks in _tasks
1245 time_slept = (int) ((now - time_before_loop) / 1000000);
1246 }
1247
1248 // Change to task list or spurious wakeup of some kind
1249 if (timedout || _should_terminate) {
1250 break;
1251 }
1252
1253 remaining = PeriodicTask::time_to_wait();
1254 if (remaining == 0) {
1255 // Last task was just disenrolled so loop around and wait until
1256 // another task gets enrolled
1257 continue;
1258 }
1259
1260 remaining -= time_slept;
1261 if (remaining <= 0) {
1262 break;
1263 }
1264 }
1265
1266 return time_slept;
1267 }
1268
1269 void WatcherThread::run() {
1270 assert(this == watcher_thread(), "just checking");
1271
1272 this->record_stack_base_and_size();
1273 this->initialize_thread_local_storage();
1274 this->set_native_thread_name(this->name());
1275 this->set_active_handles(JNIHandleBlock::allocate_block());
1276 while (true) {
1277 assert(watcher_thread() == Thread::current(), "thread consistency check");
1278 assert(watcher_thread() == this, "thread consistency check");
1279
1280 // Calculate how long it'll be until the next PeriodicTask work
1281 // should be done, and sleep that amount of time.
1282 int time_waited = sleep();
1283
1284 if (is_error_reported()) {
1285 // A fatal error has happened, the error handler(VMError::report_and_die)
1286 // should abort JVM after creating an error log file. However in some
1287 // rare cases, the error handler itself might deadlock. Here we try to
1288 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1289 //
1290 // This code is in WatcherThread because WatcherThread wakes up
1291 // periodically so the fatal error handler doesn't need to do anything;
1292 // also because the WatcherThread is less likely to crash than other
1293 // threads.
1294
1295 for (;;) {
1296 if (!ShowMessageBoxOnError
1297 && (OnError == NULL || OnError[0] == '\0')
1298 && Arguments::abort_hook() == NULL) {
1299 os::sleep(this, ErrorLogTimeout * 60 * 1000, false);
1300 fdStream err(defaultStream::output_fd());
1301 err.print_raw_cr("# [ timer expired, abort... ]");
1302 // skip atexit/vm_exit/vm_abort hooks
1303 os::die();
1304 }
1305
1306 // Wake up 5 seconds later, the fatal handler may reset OnError or
1307 // ShowMessageBoxOnError when it is ready to abort.
1308 os::sleep(this, 5 * 1000, false);
1309 }
1310 }
1311
1312 if (_should_terminate) {
1313 // check for termination before posting the next tick
1314 break;
1315 }
1316
1317 PeriodicTask::real_time_tick(time_waited);
1318 }
1319
1320 // Signal that it is terminated
1321 {
1322 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1323 _watcher_thread = NULL;
1324 Terminator_lock->notify();
1325 }
1326
1327 // Thread destructor usually does this..
1328 ThreadLocalStorage::set_thread(NULL);
1329 }
1330
1331 void WatcherThread::start() {
1332 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1333
1334 if (watcher_thread() == NULL && _startable) {
1335 _should_terminate = false;
1336 // Create the single instance of WatcherThread
1337 new WatcherThread();
1338 }
1339 }
1340
1341 void WatcherThread::make_startable() {
1342 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1343 _startable = true;
1344 }
1345
1346 void WatcherThread::stop() {
1347 {
1348 // Follow normal safepoint aware lock enter protocol since the
1349 // WatcherThread is stopped by another JavaThread.
1350 MutexLocker ml(PeriodicTask_lock);
1351 _should_terminate = true;
1352
1353 WatcherThread* watcher = watcher_thread();
1354 if (watcher != NULL) {
1355 // unpark the WatcherThread so it can see that it should terminate
1356 watcher->unpark();
1357 }
1358 }
1359
1360 MutexLocker mu(Terminator_lock);
1361
1362 while (watcher_thread() != NULL) {
1363 // This wait should make safepoint checks, wait without a timeout,
1364 // and wait as a suspend-equivalent condition.
1365 //
1366 // Note: If the FlatProfiler is running, then this thread is waiting
1367 // for the WatcherThread to terminate and the WatcherThread, via the
1368 // FlatProfiler task, is waiting for the external suspend request on
1369 // this thread to complete. wait_for_ext_suspend_completion() will
1370 // eventually timeout, but that takes time. Making this wait a
1371 // suspend-equivalent condition solves that timeout problem.
1372 //
1373 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1374 Mutex::_as_suspend_equivalent_flag);
1375 }
1376 }
1377
1378 void WatcherThread::unpark() {
1379 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1380 PeriodicTask_lock->notify();
1381 }
1382
1383 void WatcherThread::print_on(outputStream* st) const {
1384 st->print("\"%s\" ", name());
1385 Thread::print_on(st);
1386 st->cr();
1387 }
1388
1389 // ======= JavaThread ========
1390
1391 // A JavaThread is a normal Java thread
1392
1393 void JavaThread::initialize() {
1394 // Initialize fields
1395
1396 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1397 set_claimed_par_id(UINT_MAX);
1398
1399 set_saved_exception_pc(NULL);
1400 set_threadObj(NULL);
1401 _anchor.clear();
1402 set_entry_point(NULL);
1403 set_jni_functions(jni_functions());
1404 set_callee_target(NULL);
1405 set_vm_result(NULL);
1406 set_vm_result_2(NULL);
1407 set_vframe_array_head(NULL);
1408 set_vframe_array_last(NULL);
1409 set_deferred_locals(NULL);
1410 set_deopt_mark(NULL);
1411 set_deopt_nmethod(NULL);
1412 clear_must_deopt_id();
1413 set_monitor_chunks(NULL);
1414 set_next(NULL);
1415 set_thread_state(_thread_new);
1416 _terminated = _not_terminated;
1417 _privileged_stack_top = NULL;
1418 _array_for_gc = NULL;
1419 _suspend_equivalent = false;
1420 _in_deopt_handler = 0;
1421 _doing_unsafe_access = false;
1422 _stack_guard_state = stack_guard_unused;
1423 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1424 _exception_pc = 0;
1425 _exception_handler_pc = 0;
1426 _is_method_handle_return = 0;
1427 _jvmti_thread_state= NULL;
1428 _should_post_on_exceptions_flag = JNI_FALSE;
1429 _jvmti_get_loaded_classes_closure = NULL;
1430 _interp_only_mode = 0;
1431 _special_runtime_exit_condition = _no_async_condition;
1432 _pending_async_exception = NULL;
1433 _thread_stat = NULL;
1434 _thread_stat = new ThreadStatistics();
1435 _blocked_on_compilation = false;
1436 _jni_active_critical = 0;
1437 _pending_jni_exception_check_fn = NULL;
1438 _do_not_unlock_if_synchronized = false;
1439 _cached_monitor_info = NULL;
1440 _parker = Parker::Allocate(this);
1441
1442 #ifndef PRODUCT
1443 _jmp_ring_index = 0;
1444 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1445 record_jump(NULL, NULL, NULL, 0);
1446 }
1447 #endif // PRODUCT
1448
1449 set_thread_profiler(NULL);
1450 if (FlatProfiler::is_active()) {
1451 // This is where we would decide to either give each thread it's own profiler
1452 // or use one global one from FlatProfiler,
1453 // or up to some count of the number of profiled threads, etc.
1454 ThreadProfiler* pp = new ThreadProfiler();
1455 pp->engage();
1456 set_thread_profiler(pp);
1457 }
1458
1459 // Setup safepoint state info for this thread
1460 ThreadSafepointState::create(this);
1461
1462 debug_only(_java_call_counter = 0);
1463
1464 // JVMTI PopFrame support
1465 _popframe_condition = popframe_inactive;
1466 _popframe_preserved_args = NULL;
1467 _popframe_preserved_args_size = 0;
1468 _frames_to_pop_failed_realloc = 0;
1469
1470 pd_initialize();
1471 }
1472
1473 #if INCLUDE_ALL_GCS
1474 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1475 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1476 #endif // INCLUDE_ALL_GCS
1477
1478 JavaThread::JavaThread(bool is_attaching_via_jni) :
1479 Thread()
1480 #if INCLUDE_ALL_GCS
1481 , _satb_mark_queue(&_satb_mark_queue_set),
1482 _dirty_card_queue(&_dirty_card_queue_set)
1483 #endif // INCLUDE_ALL_GCS
1484 {
1485 initialize();
1486 if (is_attaching_via_jni) {
1487 _jni_attach_state = _attaching_via_jni;
1488 } else {
1489 _jni_attach_state = _not_attaching_via_jni;
1490 }
1491 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1492 }
1493
1494 bool JavaThread::reguard_stack(address cur_sp) {
1495 if (_stack_guard_state != stack_guard_yellow_disabled) {
1496 return true; // Stack already guarded or guard pages not needed.
1497 }
1498
1499 if (register_stack_overflow()) {
1500 // For those architectures which have separate register and
1501 // memory stacks, we must check the register stack to see if
1502 // it has overflowed.
1503 return false;
1504 }
1505
1506 // Java code never executes within the yellow zone: the latter is only
1507 // there to provoke an exception during stack banging. If java code
1508 // is executing there, either StackShadowPages should be larger, or
1509 // some exception code in c1, c2 or the interpreter isn't unwinding
1510 // when it should.
1511 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1512
1513 enable_stack_yellow_zone();
1514 return true;
1515 }
1516
1517 bool JavaThread::reguard_stack(void) {
1518 return reguard_stack(os::current_stack_pointer());
1519 }
1520
1521
1522 void JavaThread::block_if_vm_exited() {
1523 if (_terminated == _vm_exited) {
1524 // _vm_exited is set at safepoint, and Threads_lock is never released
1525 // we will block here forever
1526 Threads_lock->lock_without_safepoint_check();
1527 ShouldNotReachHere();
1528 }
1529 }
1530
1531
1532 // Remove this ifdef when C1 is ported to the compiler interface.
1533 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1534 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1535
1536 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1537 Thread()
1538 #if INCLUDE_ALL_GCS
1539 , _satb_mark_queue(&_satb_mark_queue_set),
1540 _dirty_card_queue(&_dirty_card_queue_set)
1541 #endif // INCLUDE_ALL_GCS
1542 {
1543 initialize();
1544 _jni_attach_state = _not_attaching_via_jni;
1545 set_entry_point(entry_point);
1546 // Create the native thread itself.
1547 // %note runtime_23
1548 os::ThreadType thr_type = os::java_thread;
1549 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1550 os::java_thread;
1551 os::create_thread(this, thr_type, stack_sz);
1552 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1553 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1554 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1555 // the exception consists of creating the exception object & initializing it, initialization
1556 // will leave the VM via a JavaCall and then all locks must be unlocked).
1557 //
1558 // The thread is still suspended when we reach here. Thread must be explicit started
1559 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1560 // by calling Threads:add. The reason why this is not done here, is because the thread
1561 // object must be fully initialized (take a look at JVM_Start)
1562 }
1563
1564 JavaThread::~JavaThread() {
1565
1566 // JSR166 -- return the parker to the free list
1567 Parker::Release(_parker);
1568 _parker = NULL;
1569
1570 // Free any remaining previous UnrollBlock
1571 vframeArray* old_array = vframe_array_last();
1572
1573 if (old_array != NULL) {
1574 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1575 old_array->set_unroll_block(NULL);
1576 delete old_info;
1577 delete old_array;
1578 }
1579
1580 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1581 if (deferred != NULL) {
1582 // This can only happen if thread is destroyed before deoptimization occurs.
1583 assert(deferred->length() != 0, "empty array!");
1584 do {
1585 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1586 deferred->remove_at(0);
1587 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1588 delete dlv;
1589 } while (deferred->length() != 0);
1590 delete deferred;
1591 }
1592
1593 // All Java related clean up happens in exit
1594 ThreadSafepointState::destroy(this);
1595 if (_thread_profiler != NULL) delete _thread_profiler;
1596 if (_thread_stat != NULL) delete _thread_stat;
1597 }
1598
1599
1600 // The first routine called by a new Java thread
1601 void JavaThread::run() {
1602 // initialize thread-local alloc buffer related fields
1603 this->initialize_tlab();
1604
1605 // used to test validity of stack trace backs
1606 this->record_base_of_stack_pointer();
1607
1608 // Record real stack base and size.
1609 this->record_stack_base_and_size();
1610
1611 // Initialize thread local storage; set before calling MutexLocker
1612 this->initialize_thread_local_storage();
1613
1614 this->create_stack_guard_pages();
1615
1616 this->cache_global_variables();
1617
1618 // Thread is now sufficient initialized to be handled by the safepoint code as being
1619 // in the VM. Change thread state from _thread_new to _thread_in_vm
1620 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1621
1622 assert(JavaThread::current() == this, "sanity check");
1623 assert(!Thread::current()->owns_locks(), "sanity check");
1624
1625 DTRACE_THREAD_PROBE(start, this);
1626
1627 // This operation might block. We call that after all safepoint checks for a new thread has
1628 // been completed.
1629 this->set_active_handles(JNIHandleBlock::allocate_block());
1630
1631 if (JvmtiExport::should_post_thread_life()) {
1632 JvmtiExport::post_thread_start(this);
1633 }
1634
1635 EventThreadStart event;
1636 if (event.should_commit()) {
1637 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1638 event.commit();
1639 }
1640
1641 // We call another function to do the rest so we are sure that the stack addresses used
1642 // from there will be lower than the stack base just computed
1643 thread_main_inner();
1644
1645 // Note, thread is no longer valid at this point!
1646 }
1647
1648
1649 void JavaThread::thread_main_inner() {
1650 assert(JavaThread::current() == this, "sanity check");
1651 assert(this->threadObj() != NULL, "just checking");
1652
1653 // Execute thread entry point unless this thread has a pending exception
1654 // or has been stopped before starting.
1655 // Note: Due to JVM_StopThread we can have pending exceptions already!
1656 if (!this->has_pending_exception() &&
1657 !java_lang_Thread::is_stillborn(this->threadObj())) {
1658 {
1659 ResourceMark rm(this);
1660 this->set_native_thread_name(this->get_thread_name());
1661 }
1662 HandleMark hm(this);
1663 this->entry_point()(this, this);
1664 }
1665
1666 DTRACE_THREAD_PROBE(stop, this);
1667
1668 this->exit(false);
1669 delete this;
1670 }
1671
1672
1673 static void ensure_join(JavaThread* thread) {
1674 // We do not need to grap the Threads_lock, since we are operating on ourself.
1675 Handle threadObj(thread, thread->threadObj());
1676 assert(threadObj.not_null(), "java thread object must exist");
1677 ObjectLocker lock(threadObj, thread);
1678 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1679 thread->clear_pending_exception();
1680 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1681 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1682 // Clear the native thread instance - this makes isAlive return false and allows the join()
1683 // to complete once we've done the notify_all below
1684 java_lang_Thread::set_thread(threadObj(), NULL);
1685 lock.notify_all(thread);
1686 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1687 thread->clear_pending_exception();
1688 }
1689
1690
1691 // For any new cleanup additions, please check to see if they need to be applied to
1692 // cleanup_failed_attach_current_thread as well.
1693 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1694 assert(this == JavaThread::current(), "thread consistency check");
1695
1696 HandleMark hm(this);
1697 Handle uncaught_exception(this, this->pending_exception());
1698 this->clear_pending_exception();
1699 Handle threadObj(this, this->threadObj());
1700 assert(threadObj.not_null(), "Java thread object should be created");
1701
1702 if (get_thread_profiler() != NULL) {
1703 get_thread_profiler()->disengage();
1704 ResourceMark rm;
1705 get_thread_profiler()->print(get_thread_name());
1706 }
1707
1708
1709 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1710 {
1711 EXCEPTION_MARK;
1712
1713 CLEAR_PENDING_EXCEPTION;
1714 }
1715 if (!destroy_vm) {
1716 if (uncaught_exception.not_null()) {
1717 EXCEPTION_MARK;
1718 // Call method Thread.dispatchUncaughtException().
1719 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1720 JavaValue result(T_VOID);
1721 JavaCalls::call_virtual(&result,
1722 threadObj, thread_klass,
1723 vmSymbols::dispatchUncaughtException_name(),
1724 vmSymbols::throwable_void_signature(),
1725 uncaught_exception,
1726 THREAD);
1727 if (HAS_PENDING_EXCEPTION) {
1728 ResourceMark rm(this);
1729 jio_fprintf(defaultStream::error_stream(),
1730 "\nException: %s thrown from the UncaughtExceptionHandler"
1731 " in thread \"%s\"\n",
1732 pending_exception()->klass()->external_name(),
1733 get_thread_name());
1734 CLEAR_PENDING_EXCEPTION;
1735 }
1736 }
1737
1738 // Called before the java thread exit since we want to read info
1739 // from java_lang_Thread object
1740 EventThreadEnd event;
1741 if (event.should_commit()) {
1742 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1743 event.commit();
1744 }
1745
1746 // Call after last event on thread
1747 EVENT_THREAD_EXIT(this);
1748
1749 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1750 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1751 // is deprecated anyhow.
1752 if (!is_Compiler_thread()) {
1753 int count = 3;
1754 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1755 EXCEPTION_MARK;
1756 JavaValue result(T_VOID);
1757 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1758 JavaCalls::call_virtual(&result,
1759 threadObj, thread_klass,
1760 vmSymbols::exit_method_name(),
1761 vmSymbols::void_method_signature(),
1762 THREAD);
1763 CLEAR_PENDING_EXCEPTION;
1764 }
1765 }
1766 // notify JVMTI
1767 if (JvmtiExport::should_post_thread_life()) {
1768 JvmtiExport::post_thread_end(this);
1769 }
1770
1771 // We have notified the agents that we are exiting, before we go on,
1772 // we must check for a pending external suspend request and honor it
1773 // in order to not surprise the thread that made the suspend request.
1774 while (true) {
1775 {
1776 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1777 if (!is_external_suspend()) {
1778 set_terminated(_thread_exiting);
1779 ThreadService::current_thread_exiting(this);
1780 break;
1781 }
1782 // Implied else:
1783 // Things get a little tricky here. We have a pending external
1784 // suspend request, but we are holding the SR_lock so we
1785 // can't just self-suspend. So we temporarily drop the lock
1786 // and then self-suspend.
1787 }
1788
1789 ThreadBlockInVM tbivm(this);
1790 java_suspend_self();
1791
1792 // We're done with this suspend request, but we have to loop around
1793 // and check again. Eventually we will get SR_lock without a pending
1794 // external suspend request and will be able to mark ourselves as
1795 // exiting.
1796 }
1797 // no more external suspends are allowed at this point
1798 } else {
1799 // before_exit() has already posted JVMTI THREAD_END events
1800 }
1801
1802 // Notify waiters on thread object. This has to be done after exit() is called
1803 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1804 // group should have the destroyed bit set before waiters are notified).
1805 ensure_join(this);
1806 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1807
1808 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1809 // held by this thread must be released. The spec does not distinguish
1810 // between JNI-acquired and regular Java monitors. We can only see
1811 // regular Java monitors here if monitor enter-exit matching is broken.
1812 //
1813 // Optionally release any monitors for regular JavaThread exits. This
1814 // is provided as a work around for any bugs in monitor enter-exit
1815 // matching. This can be expensive so it is not enabled by default.
1816 // ObjectMonitor::Knob_ExitRelease is a superset of the
1817 // JNIDetachReleasesMonitors option.
1818 //
1819 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1820 // ObjectSynchronizer::release_monitors_owned_by_thread().
1821 if ((exit_type == jni_detach && JNIDetachReleasesMonitors) ||
1822 ObjectMonitor::Knob_ExitRelease) {
1823 // Sanity check even though JNI DetachCurrentThread() would have
1824 // returned JNI_ERR if there was a Java frame. JavaThread exit
1825 // should be done executing Java code by the time we get here.
1826 assert(!this->has_last_Java_frame(),
1827 "should not have a Java frame when detaching or exiting");
1828 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1829 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1830 }
1831
1832 // These things needs to be done while we are still a Java Thread. Make sure that thread
1833 // is in a consistent state, in case GC happens
1834 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1835
1836 if (active_handles() != NULL) {
1837 JNIHandleBlock* block = active_handles();
1838 set_active_handles(NULL);
1839 JNIHandleBlock::release_block(block);
1840 }
1841
1842 if (free_handle_block() != NULL) {
1843 JNIHandleBlock* block = free_handle_block();
1844 set_free_handle_block(NULL);
1845 JNIHandleBlock::release_block(block);
1846 }
1847
1848 // These have to be removed while this is still a valid thread.
1849 remove_stack_guard_pages();
1850
1851 if (UseTLAB) {
1852 tlab().make_parsable(true); // retire TLAB
1853 }
1854
1855 if (JvmtiEnv::environments_might_exist()) {
1856 JvmtiExport::cleanup_thread(this);
1857 }
1858
1859 // We must flush any deferred card marks before removing a thread from
1860 // the list of active threads.
1861 Universe::heap()->flush_deferred_store_barrier(this);
1862 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1863
1864 #if INCLUDE_ALL_GCS
1865 // We must flush the G1-related buffers before removing a thread
1866 // from the list of active threads. We must do this after any deferred
1867 // card marks have been flushed (above) so that any entries that are
1868 // added to the thread's dirty card queue as a result are not lost.
1869 if (UseG1GC) {
1870 flush_barrier_queues();
1871 }
1872 #endif // INCLUDE_ALL_GCS
1873
1874 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1875 Threads::remove(this);
1876 }
1877
1878 #if INCLUDE_ALL_GCS
1879 // Flush G1-related queues.
1880 void JavaThread::flush_barrier_queues() {
1881 satb_mark_queue().flush();
1882 dirty_card_queue().flush();
1883 }
1884
1885 void JavaThread::initialize_queues() {
1886 assert(!SafepointSynchronize::is_at_safepoint(),
1887 "we should not be at a safepoint");
1888
1889 ObjPtrQueue& satb_queue = satb_mark_queue();
1890 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1891 // The SATB queue should have been constructed with its active
1892 // field set to false.
1893 assert(!satb_queue.is_active(), "SATB queue should not be active");
1894 assert(satb_queue.is_empty(), "SATB queue should be empty");
1895 // If we are creating the thread during a marking cycle, we should
1896 // set the active field of the SATB queue to true.
1897 if (satb_queue_set.is_active()) {
1898 satb_queue.set_active(true);
1899 }
1900
1901 DirtyCardQueue& dirty_queue = dirty_card_queue();
1902 // The dirty card queue should have been constructed with its
1903 // active field set to true.
1904 assert(dirty_queue.is_active(), "dirty card queue should be active");
1905 }
1906 #endif // INCLUDE_ALL_GCS
1907
1908 void JavaThread::cleanup_failed_attach_current_thread() {
1909 if (get_thread_profiler() != NULL) {
1910 get_thread_profiler()->disengage();
1911 ResourceMark rm;
1912 get_thread_profiler()->print(get_thread_name());
1913 }
1914
1915 if (active_handles() != NULL) {
1916 JNIHandleBlock* block = active_handles();
1917 set_active_handles(NULL);
1918 JNIHandleBlock::release_block(block);
1919 }
1920
1921 if (free_handle_block() != NULL) {
1922 JNIHandleBlock* block = free_handle_block();
1923 set_free_handle_block(NULL);
1924 JNIHandleBlock::release_block(block);
1925 }
1926
1927 // These have to be removed while this is still a valid thread.
1928 remove_stack_guard_pages();
1929
1930 if (UseTLAB) {
1931 tlab().make_parsable(true); // retire TLAB, if any
1932 }
1933
1934 #if INCLUDE_ALL_GCS
1935 if (UseG1GC) {
1936 flush_barrier_queues();
1937 }
1938 #endif // INCLUDE_ALL_GCS
1939
1940 Threads::remove(this);
1941 delete this;
1942 }
1943
1944
1945
1946
1947 JavaThread* JavaThread::active() {
1948 Thread* thread = ThreadLocalStorage::thread();
1949 assert(thread != NULL, "just checking");
1950 if (thread->is_Java_thread()) {
1951 return (JavaThread*) thread;
1952 } else {
1953 assert(thread->is_VM_thread(), "this must be a vm thread");
1954 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1955 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1956 assert(ret->is_Java_thread(), "must be a Java thread");
1957 return ret;
1958 }
1959 }
1960
1961 bool JavaThread::is_lock_owned(address adr) const {
1962 if (Thread::is_lock_owned(adr)) return true;
1963
1964 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1965 if (chunk->contains(adr)) return true;
1966 }
1967
1968 return false;
1969 }
1970
1971
1972 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1973 chunk->set_next(monitor_chunks());
1974 set_monitor_chunks(chunk);
1975 }
1976
1977 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1978 guarantee(monitor_chunks() != NULL, "must be non empty");
1979 if (monitor_chunks() == chunk) {
1980 set_monitor_chunks(chunk->next());
1981 } else {
1982 MonitorChunk* prev = monitor_chunks();
1983 while (prev->next() != chunk) prev = prev->next();
1984 prev->set_next(chunk->next());
1985 }
1986 }
1987
1988 // JVM support.
1989
1990 // Note: this function shouldn't block if it's called in
1991 // _thread_in_native_trans state (such as from
1992 // check_special_condition_for_native_trans()).
1993 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1994
1995 if (has_last_Java_frame() && has_async_condition()) {
1996 // If we are at a polling page safepoint (not a poll return)
1997 // then we must defer async exception because live registers
1998 // will be clobbered by the exception path. Poll return is
1999 // ok because the call we a returning from already collides
2000 // with exception handling registers and so there is no issue.
2001 // (The exception handling path kills call result registers but
2002 // this is ok since the exception kills the result anyway).
2003
2004 if (is_at_poll_safepoint()) {
2005 // if the code we are returning to has deoptimized we must defer
2006 // the exception otherwise live registers get clobbered on the
2007 // exception path before deoptimization is able to retrieve them.
2008 //
2009 RegisterMap map(this, false);
2010 frame caller_fr = last_frame().sender(&map);
2011 assert(caller_fr.is_compiled_frame(), "what?");
2012 if (caller_fr.is_deoptimized_frame()) {
2013 if (TraceExceptions) {
2014 ResourceMark rm;
2015 tty->print_cr("deferred async exception at compiled safepoint");
2016 }
2017 return;
2018 }
2019 }
2020 }
2021
2022 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2023 if (condition == _no_async_condition) {
2024 // Conditions have changed since has_special_runtime_exit_condition()
2025 // was called:
2026 // - if we were here only because of an external suspend request,
2027 // then that was taken care of above (or cancelled) so we are done
2028 // - if we were here because of another async request, then it has
2029 // been cleared between the has_special_runtime_exit_condition()
2030 // and now so again we are done
2031 return;
2032 }
2033
2034 // Check for pending async. exception
2035 if (_pending_async_exception != NULL) {
2036 // Only overwrite an already pending exception, if it is not a threadDeath.
2037 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2038
2039 // We cannot call Exceptions::_throw(...) here because we cannot block
2040 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2041
2042 if (TraceExceptions) {
2043 ResourceMark rm;
2044 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2045 if (has_last_Java_frame()) {
2046 frame f = last_frame();
2047 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2048 }
2049 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2050 }
2051 _pending_async_exception = NULL;
2052 clear_has_async_exception();
2053 }
2054 }
2055
2056 if (check_unsafe_error &&
2057 condition == _async_unsafe_access_error && !has_pending_exception()) {
2058 condition = _no_async_condition; // done
2059 switch (thread_state()) {
2060 case _thread_in_vm: {
2061 JavaThread* THREAD = this;
2062 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2063 }
2064 case _thread_in_native: {
2065 ThreadInVMfromNative tiv(this);
2066 JavaThread* THREAD = this;
2067 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2068 }
2069 case _thread_in_Java: {
2070 ThreadInVMfromJava tiv(this);
2071 JavaThread* THREAD = this;
2072 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2073 }
2074 default:
2075 ShouldNotReachHere();
2076 }
2077 }
2078
2079 assert(condition == _no_async_condition || has_pending_exception() ||
2080 (!check_unsafe_error && condition == _async_unsafe_access_error),
2081 "must have handled the async condition, if no exception");
2082 }
2083
2084 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2085 //
2086 // Check for pending external suspend. Internal suspend requests do
2087 // not use handle_special_runtime_exit_condition().
2088 // If JNIEnv proxies are allowed, don't self-suspend if the target
2089 // thread is not the current thread. In older versions of jdbx, jdbx
2090 // threads could call into the VM with another thread's JNIEnv so we
2091 // can be here operating on behalf of a suspended thread (4432884).
2092 bool do_self_suspend = is_external_suspend_with_lock();
2093 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2094 //
2095 // Because thread is external suspended the safepoint code will count
2096 // thread as at a safepoint. This can be odd because we can be here
2097 // as _thread_in_Java which would normally transition to _thread_blocked
2098 // at a safepoint. We would like to mark the thread as _thread_blocked
2099 // before calling java_suspend_self like all other callers of it but
2100 // we must then observe proper safepoint protocol. (We can't leave
2101 // _thread_blocked with a safepoint in progress). However we can be
2102 // here as _thread_in_native_trans so we can't use a normal transition
2103 // constructor/destructor pair because they assert on that type of
2104 // transition. We could do something like:
2105 //
2106 // JavaThreadState state = thread_state();
2107 // set_thread_state(_thread_in_vm);
2108 // {
2109 // ThreadBlockInVM tbivm(this);
2110 // java_suspend_self()
2111 // }
2112 // set_thread_state(_thread_in_vm_trans);
2113 // if (safepoint) block;
2114 // set_thread_state(state);
2115 //
2116 // but that is pretty messy. Instead we just go with the way the
2117 // code has worked before and note that this is the only path to
2118 // java_suspend_self that doesn't put the thread in _thread_blocked
2119 // mode.
2120
2121 frame_anchor()->make_walkable(this);
2122 java_suspend_self();
2123
2124 // We might be here for reasons in addition to the self-suspend request
2125 // so check for other async requests.
2126 }
2127
2128 if (check_asyncs) {
2129 check_and_handle_async_exceptions();
2130 }
2131 }
2132
2133 void JavaThread::send_thread_stop(oop java_throwable) {
2134 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2135 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2136 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2137
2138 // Do not throw asynchronous exceptions against the compiler thread
2139 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2140 if (is_Compiler_thread()) return;
2141
2142 {
2143 // Actually throw the Throwable against the target Thread - however
2144 // only if there is no thread death exception installed already.
2145 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2146 // If the topmost frame is a runtime stub, then we are calling into
2147 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2148 // must deoptimize the caller before continuing, as the compiled exception handler table
2149 // may not be valid
2150 if (has_last_Java_frame()) {
2151 frame f = last_frame();
2152 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2153 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2154 RegisterMap reg_map(this, UseBiasedLocking);
2155 frame compiled_frame = f.sender(®_map);
2156 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2157 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2158 }
2159 }
2160 }
2161
2162 // Set async. pending exception in thread.
2163 set_pending_async_exception(java_throwable);
2164
2165 if (TraceExceptions) {
2166 ResourceMark rm;
2167 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2168 }
2169 // for AbortVMOnException flag
2170 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2171 }
2172 }
2173
2174
2175 // Interrupt thread so it will wake up from a potential wait()
2176 Thread::interrupt(this);
2177 }
2178
2179 // External suspension mechanism.
2180 //
2181 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2182 // to any VM_locks and it is at a transition
2183 // Self-suspension will happen on the transition out of the vm.
2184 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2185 //
2186 // Guarantees on return:
2187 // + Target thread will not execute any new bytecode (that's why we need to
2188 // force a safepoint)
2189 // + Target thread will not enter any new monitors
2190 //
2191 void JavaThread::java_suspend() {
2192 { MutexLocker mu(Threads_lock);
2193 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2194 return;
2195 }
2196 }
2197
2198 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2199 if (!is_external_suspend()) {
2200 // a racing resume has cancelled us; bail out now
2201 return;
2202 }
2203
2204 // suspend is done
2205 uint32_t debug_bits = 0;
2206 // Warning: is_ext_suspend_completed() may temporarily drop the
2207 // SR_lock to allow the thread to reach a stable thread state if
2208 // it is currently in a transient thread state.
2209 if (is_ext_suspend_completed(false /* !called_by_wait */,
2210 SuspendRetryDelay, &debug_bits)) {
2211 return;
2212 }
2213 }
2214
2215 VM_ForceSafepoint vm_suspend;
2216 VMThread::execute(&vm_suspend);
2217 }
2218
2219 // Part II of external suspension.
2220 // A JavaThread self suspends when it detects a pending external suspend
2221 // request. This is usually on transitions. It is also done in places
2222 // where continuing to the next transition would surprise the caller,
2223 // e.g., monitor entry.
2224 //
2225 // Returns the number of times that the thread self-suspended.
2226 //
2227 // Note: DO NOT call java_suspend_self() when you just want to block current
2228 // thread. java_suspend_self() is the second stage of cooperative
2229 // suspension for external suspend requests and should only be used
2230 // to complete an external suspend request.
2231 //
2232 int JavaThread::java_suspend_self() {
2233 int ret = 0;
2234
2235 // we are in the process of exiting so don't suspend
2236 if (is_exiting()) {
2237 clear_external_suspend();
2238 return ret;
2239 }
2240
2241 assert(_anchor.walkable() ||
2242 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2243 "must have walkable stack");
2244
2245 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2246
2247 assert(!this->is_ext_suspended(),
2248 "a thread trying to self-suspend should not already be suspended");
2249
2250 if (this->is_suspend_equivalent()) {
2251 // If we are self-suspending as a result of the lifting of a
2252 // suspend equivalent condition, then the suspend_equivalent
2253 // flag is not cleared until we set the ext_suspended flag so
2254 // that wait_for_ext_suspend_completion() returns consistent
2255 // results.
2256 this->clear_suspend_equivalent();
2257 }
2258
2259 // A racing resume may have cancelled us before we grabbed SR_lock
2260 // above. Or another external suspend request could be waiting for us
2261 // by the time we return from SR_lock()->wait(). The thread
2262 // that requested the suspension may already be trying to walk our
2263 // stack and if we return now, we can change the stack out from under
2264 // it. This would be a "bad thing (TM)" and cause the stack walker
2265 // to crash. We stay self-suspended until there are no more pending
2266 // external suspend requests.
2267 while (is_external_suspend()) {
2268 ret++;
2269 this->set_ext_suspended();
2270
2271 // _ext_suspended flag is cleared by java_resume()
2272 while (is_ext_suspended()) {
2273 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2274 }
2275 }
2276
2277 return ret;
2278 }
2279
2280 #ifdef ASSERT
2281 // verify the JavaThread has not yet been published in the Threads::list, and
2282 // hence doesn't need protection from concurrent access at this stage
2283 void JavaThread::verify_not_published() {
2284 if (!Threads_lock->owned_by_self()) {
2285 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2286 assert(!Threads::includes(this),
2287 "java thread shouldn't have been published yet!");
2288 } else {
2289 assert(!Threads::includes(this),
2290 "java thread shouldn't have been published yet!");
2291 }
2292 }
2293 #endif
2294
2295 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2296 // progress or when _suspend_flags is non-zero.
2297 // Current thread needs to self-suspend if there is a suspend request and/or
2298 // block if a safepoint is in progress.
2299 // Async exception ISN'T checked.
2300 // Note only the ThreadInVMfromNative transition can call this function
2301 // directly and when thread state is _thread_in_native_trans
2302 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2303 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2304
2305 JavaThread *curJT = JavaThread::current();
2306 bool do_self_suspend = thread->is_external_suspend();
2307
2308 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2309
2310 // If JNIEnv proxies are allowed, don't self-suspend if the target
2311 // thread is not the current thread. In older versions of jdbx, jdbx
2312 // threads could call into the VM with another thread's JNIEnv so we
2313 // can be here operating on behalf of a suspended thread (4432884).
2314 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2315 JavaThreadState state = thread->thread_state();
2316
2317 // We mark this thread_blocked state as a suspend-equivalent so
2318 // that a caller to is_ext_suspend_completed() won't be confused.
2319 // The suspend-equivalent state is cleared by java_suspend_self().
2320 thread->set_suspend_equivalent();
2321
2322 // If the safepoint code sees the _thread_in_native_trans state, it will
2323 // wait until the thread changes to other thread state. There is no
2324 // guarantee on how soon we can obtain the SR_lock and complete the
2325 // self-suspend request. It would be a bad idea to let safepoint wait for
2326 // too long. Temporarily change the state to _thread_blocked to
2327 // let the VM thread know that this thread is ready for GC. The problem
2328 // of changing thread state is that safepoint could happen just after
2329 // java_suspend_self() returns after being resumed, and VM thread will
2330 // see the _thread_blocked state. We must check for safepoint
2331 // after restoring the state and make sure we won't leave while a safepoint
2332 // is in progress.
2333 thread->set_thread_state(_thread_blocked);
2334 thread->java_suspend_self();
2335 thread->set_thread_state(state);
2336 // Make sure new state is seen by VM thread
2337 if (os::is_MP()) {
2338 if (UseMembar) {
2339 // Force a fence between the write above and read below
2340 OrderAccess::fence();
2341 } else {
2342 // Must use this rather than serialization page in particular on Windows
2343 InterfaceSupport::serialize_memory(thread);
2344 }
2345 }
2346 }
2347
2348 if (SafepointSynchronize::do_call_back()) {
2349 // If we are safepointing, then block the caller which may not be
2350 // the same as the target thread (see above).
2351 SafepointSynchronize::block(curJT);
2352 }
2353
2354 if (thread->is_deopt_suspend()) {
2355 thread->clear_deopt_suspend();
2356 RegisterMap map(thread, false);
2357 frame f = thread->last_frame();
2358 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2359 f = f.sender(&map);
2360 }
2361 if (f.id() == thread->must_deopt_id()) {
2362 thread->clear_must_deopt_id();
2363 f.deoptimize(thread);
2364 } else {
2365 fatal("missed deoptimization!");
2366 }
2367 }
2368 }
2369
2370 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2371 // progress or when _suspend_flags is non-zero.
2372 // Current thread needs to self-suspend if there is a suspend request and/or
2373 // block if a safepoint is in progress.
2374 // Also check for pending async exception (not including unsafe access error).
2375 // Note only the native==>VM/Java barriers can call this function and when
2376 // thread state is _thread_in_native_trans.
2377 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2378 check_safepoint_and_suspend_for_native_trans(thread);
2379
2380 if (thread->has_async_exception()) {
2381 // We are in _thread_in_native_trans state, don't handle unsafe
2382 // access error since that may block.
2383 thread->check_and_handle_async_exceptions(false);
2384 }
2385 }
2386
2387 // This is a variant of the normal
2388 // check_special_condition_for_native_trans with slightly different
2389 // semantics for use by critical native wrappers. It does all the
2390 // normal checks but also performs the transition back into
2391 // thread_in_Java state. This is required so that critical natives
2392 // can potentially block and perform a GC if they are the last thread
2393 // exiting the GC_locker.
2394 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2395 check_special_condition_for_native_trans(thread);
2396
2397 // Finish the transition
2398 thread->set_thread_state(_thread_in_Java);
2399
2400 if (thread->do_critical_native_unlock()) {
2401 ThreadInVMfromJavaNoAsyncException tiv(thread);
2402 GC_locker::unlock_critical(thread);
2403 thread->clear_critical_native_unlock();
2404 }
2405 }
2406
2407 // We need to guarantee the Threads_lock here, since resumes are not
2408 // allowed during safepoint synchronization
2409 // Can only resume from an external suspension
2410 void JavaThread::java_resume() {
2411 assert_locked_or_safepoint(Threads_lock);
2412
2413 // Sanity check: thread is gone, has started exiting or the thread
2414 // was not externally suspended.
2415 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2416 return;
2417 }
2418
2419 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2420
2421 clear_external_suspend();
2422
2423 if (is_ext_suspended()) {
2424 clear_ext_suspended();
2425 SR_lock()->notify_all();
2426 }
2427 }
2428
2429 void JavaThread::create_stack_guard_pages() {
2430 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2431 address low_addr = stack_base() - stack_size();
2432 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2433
2434 int allocate = os::allocate_stack_guard_pages();
2435 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2436
2437 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2438 warning("Attempt to allocate stack guard pages failed.");
2439 return;
2440 }
2441
2442 if (os::guard_memory((char *) low_addr, len)) {
2443 _stack_guard_state = stack_guard_enabled;
2444 } else {
2445 warning("Attempt to protect stack guard pages failed.");
2446 if (os::uncommit_memory((char *) low_addr, len)) {
2447 warning("Attempt to deallocate stack guard pages failed.");
2448 }
2449 }
2450 }
2451
2452 void JavaThread::remove_stack_guard_pages() {
2453 assert(Thread::current() == this, "from different thread");
2454 if (_stack_guard_state == stack_guard_unused) return;
2455 address low_addr = stack_base() - stack_size();
2456 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2457
2458 if (os::allocate_stack_guard_pages()) {
2459 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2460 _stack_guard_state = stack_guard_unused;
2461 } else {
2462 warning("Attempt to deallocate stack guard pages failed.");
2463 }
2464 } else {
2465 if (_stack_guard_state == stack_guard_unused) return;
2466 if (os::unguard_memory((char *) low_addr, len)) {
2467 _stack_guard_state = stack_guard_unused;
2468 } else {
2469 warning("Attempt to unprotect stack guard pages failed.");
2470 }
2471 }
2472 }
2473
2474 void JavaThread::enable_stack_yellow_zone() {
2475 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2476 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2477
2478 // The base notation is from the stacks point of view, growing downward.
2479 // We need to adjust it to work correctly with guard_memory()
2480 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2481
2482 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2483 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2484
2485 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2486 _stack_guard_state = stack_guard_enabled;
2487 } else {
2488 warning("Attempt to guard stack yellow zone failed.");
2489 }
2490 enable_register_stack_guard();
2491 }
2492
2493 void JavaThread::disable_stack_yellow_zone() {
2494 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2495 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2496
2497 // Simply return if called for a thread that does not use guard pages.
2498 if (_stack_guard_state == stack_guard_unused) return;
2499
2500 // The base notation is from the stacks point of view, growing downward.
2501 // We need to adjust it to work correctly with guard_memory()
2502 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2503
2504 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2505 _stack_guard_state = stack_guard_yellow_disabled;
2506 } else {
2507 warning("Attempt to unguard stack yellow zone failed.");
2508 }
2509 disable_register_stack_guard();
2510 }
2511
2512 void JavaThread::enable_stack_red_zone() {
2513 // The base notation is from the stacks point of view, growing downward.
2514 // We need to adjust it to work correctly with guard_memory()
2515 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2516 address base = stack_red_zone_base() - stack_red_zone_size();
2517
2518 guarantee(base < stack_base(), "Error calculating stack red zone");
2519 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2520
2521 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2522 warning("Attempt to guard stack red zone failed.");
2523 }
2524 }
2525
2526 void JavaThread::disable_stack_red_zone() {
2527 // The base notation is from the stacks point of view, growing downward.
2528 // We need to adjust it to work correctly with guard_memory()
2529 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2530 address base = stack_red_zone_base() - stack_red_zone_size();
2531 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2532 warning("Attempt to unguard stack red zone failed.");
2533 }
2534 }
2535
2536 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2537 // ignore is there is no stack
2538 if (!has_last_Java_frame()) return;
2539 // traverse the stack frames. Starts from top frame.
2540 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2541 frame* fr = fst.current();
2542 f(fr, fst.register_map());
2543 }
2544 }
2545
2546
2547 #ifndef PRODUCT
2548 // Deoptimization
2549 // Function for testing deoptimization
2550 void JavaThread::deoptimize() {
2551 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2552 StackFrameStream fst(this, UseBiasedLocking);
2553 bool deopt = false; // Dump stack only if a deopt actually happens.
2554 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2555 // Iterate over all frames in the thread and deoptimize
2556 for (; !fst.is_done(); fst.next()) {
2557 if (fst.current()->can_be_deoptimized()) {
2558
2559 if (only_at) {
2560 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2561 // consists of comma or carriage return separated numbers so
2562 // search for the current bci in that string.
2563 address pc = fst.current()->pc();
2564 nmethod* nm = (nmethod*) fst.current()->cb();
2565 ScopeDesc* sd = nm->scope_desc_at(pc);
2566 char buffer[8];
2567 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2568 size_t len = strlen(buffer);
2569 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2570 while (found != NULL) {
2571 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2572 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2573 // Check that the bci found is bracketed by terminators.
2574 break;
2575 }
2576 found = strstr(found + 1, buffer);
2577 }
2578 if (!found) {
2579 continue;
2580 }
2581 }
2582
2583 if (DebugDeoptimization && !deopt) {
2584 deopt = true; // One-time only print before deopt
2585 tty->print_cr("[BEFORE Deoptimization]");
2586 trace_frames();
2587 trace_stack();
2588 }
2589 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2590 }
2591 }
2592
2593 if (DebugDeoptimization && deopt) {
2594 tty->print_cr("[AFTER Deoptimization]");
2595 trace_frames();
2596 }
2597 }
2598
2599
2600 // Make zombies
2601 void JavaThread::make_zombies() {
2602 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2603 if (fst.current()->can_be_deoptimized()) {
2604 // it is a Java nmethod
2605 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2606 nm->make_not_entrant();
2607 }
2608 }
2609 }
2610 #endif // PRODUCT
2611
2612
2613 void JavaThread::deoptimized_wrt_marked_nmethods() {
2614 if (!has_last_Java_frame()) return;
2615 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2616 StackFrameStream fst(this, UseBiasedLocking);
2617 for (; !fst.is_done(); fst.next()) {
2618 if (fst.current()->should_be_deoptimized()) {
2619 if (LogCompilation && xtty != NULL) {
2620 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2621 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2622 this->name(), nm != NULL ? nm->compile_id() : -1);
2623 }
2624
2625 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2626 }
2627 }
2628 }
2629
2630
2631 // If the caller is a NamedThread, then remember, in the current scope,
2632 // the given JavaThread in its _processed_thread field.
2633 class RememberProcessedThread: public StackObj {
2634 NamedThread* _cur_thr;
2635 public:
2636 RememberProcessedThread(JavaThread* jthr) {
2637 Thread* thread = Thread::current();
2638 if (thread->is_Named_thread()) {
2639 _cur_thr = (NamedThread *)thread;
2640 _cur_thr->set_processed_thread(jthr);
2641 } else {
2642 _cur_thr = NULL;
2643 }
2644 }
2645
2646 ~RememberProcessedThread() {
2647 if (_cur_thr) {
2648 _cur_thr->set_processed_thread(NULL);
2649 }
2650 }
2651 };
2652
2653 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2654 // Verify that the deferred card marks have been flushed.
2655 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2656
2657 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2658 // since there may be more than one thread using each ThreadProfiler.
2659
2660 // Traverse the GCHandles
2661 Thread::oops_do(f, cld_f, cf);
2662
2663 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2664 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2665
2666 if (has_last_Java_frame()) {
2667 // Record JavaThread to GC thread
2668 RememberProcessedThread rpt(this);
2669
2670 // Traverse the privileged stack
2671 if (_privileged_stack_top != NULL) {
2672 _privileged_stack_top->oops_do(f);
2673 }
2674
2675 // traverse the registered growable array
2676 if (_array_for_gc != NULL) {
2677 for (int index = 0; index < _array_for_gc->length(); index++) {
2678 f->do_oop(_array_for_gc->adr_at(index));
2679 }
2680 }
2681
2682 // Traverse the monitor chunks
2683 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2684 chunk->oops_do(f);
2685 }
2686
2687 // Traverse the execution stack
2688 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2689 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2690 }
2691 }
2692
2693 // callee_target is never live across a gc point so NULL it here should
2694 // it still contain a methdOop.
2695
2696 set_callee_target(NULL);
2697
2698 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2699 // If we have deferred set_locals there might be oops waiting to be
2700 // written
2701 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2702 if (list != NULL) {
2703 for (int i = 0; i < list->length(); i++) {
2704 list->at(i)->oops_do(f);
2705 }
2706 }
2707
2708 // Traverse instance variables at the end since the GC may be moving things
2709 // around using this function
2710 f->do_oop((oop*) &_threadObj);
2711 f->do_oop((oop*) &_vm_result);
2712 f->do_oop((oop*) &_exception_oop);
2713 f->do_oop((oop*) &_pending_async_exception);
2714
2715 if (jvmti_thread_state() != NULL) {
2716 jvmti_thread_state()->oops_do(f);
2717 }
2718 }
2719
2720 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2721 Thread::nmethods_do(cf); // (super method is a no-op)
2722
2723 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2724 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2725
2726 if (has_last_Java_frame()) {
2727 // Traverse the execution stack
2728 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2729 fst.current()->nmethods_do(cf);
2730 }
2731 }
2732 }
2733
2734 void JavaThread::metadata_do(void f(Metadata*)) {
2735 if (has_last_Java_frame()) {
2736 // Traverse the execution stack to call f() on the methods in the stack
2737 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2738 fst.current()->metadata_do(f);
2739 }
2740 } else if (is_Compiler_thread()) {
2741 // need to walk ciMetadata in current compile tasks to keep alive.
2742 CompilerThread* ct = (CompilerThread*)this;
2743 if (ct->env() != NULL) {
2744 ct->env()->metadata_do(f);
2745 }
2746 if (ct->task() != NULL) {
2747 ct->task()->metadata_do(f);
2748 }
2749 }
2750 }
2751
2752 // Printing
2753 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2754 switch (_thread_state) {
2755 case _thread_uninitialized: return "_thread_uninitialized";
2756 case _thread_new: return "_thread_new";
2757 case _thread_new_trans: return "_thread_new_trans";
2758 case _thread_in_native: return "_thread_in_native";
2759 case _thread_in_native_trans: return "_thread_in_native_trans";
2760 case _thread_in_vm: return "_thread_in_vm";
2761 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2762 case _thread_in_Java: return "_thread_in_Java";
2763 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2764 case _thread_blocked: return "_thread_blocked";
2765 case _thread_blocked_trans: return "_thread_blocked_trans";
2766 default: return "unknown thread state";
2767 }
2768 }
2769
2770 #ifndef PRODUCT
2771 void JavaThread::print_thread_state_on(outputStream *st) const {
2772 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2773 };
2774 void JavaThread::print_thread_state() const {
2775 print_thread_state_on(tty);
2776 }
2777 #endif // PRODUCT
2778
2779 // Called by Threads::print() for VM_PrintThreads operation
2780 void JavaThread::print_on(outputStream *st) const {
2781 st->print("\"%s\" ", get_thread_name());
2782 oop thread_oop = threadObj();
2783 if (thread_oop != NULL) {
2784 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2785 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2786 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2787 }
2788 Thread::print_on(st);
2789 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2790 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2791 if (thread_oop != NULL) {
2792 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2793 }
2794 #ifndef PRODUCT
2795 print_thread_state_on(st);
2796 _safepoint_state->print_on(st);
2797 #endif // PRODUCT
2798 }
2799
2800 // Called by fatal error handler. The difference between this and
2801 // JavaThread::print() is that we can't grab lock or allocate memory.
2802 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2803 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2804 oop thread_obj = threadObj();
2805 if (thread_obj != NULL) {
2806 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2807 }
2808 st->print(" [");
2809 st->print("%s", _get_thread_state_name(_thread_state));
2810 if (osthread()) {
2811 st->print(", id=%d", osthread()->thread_id());
2812 }
2813 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2814 _stack_base - _stack_size, _stack_base);
2815 st->print("]");
2816 return;
2817 }
2818
2819 // Verification
2820
2821 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2822
2823 void JavaThread::verify() {
2824 // Verify oops in the thread.
2825 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2826
2827 // Verify the stack frames.
2828 frames_do(frame_verify);
2829 }
2830
2831 // CR 6300358 (sub-CR 2137150)
2832 // Most callers of this method assume that it can't return NULL but a
2833 // thread may not have a name whilst it is in the process of attaching to
2834 // the VM - see CR 6412693, and there are places where a JavaThread can be
2835 // seen prior to having it's threadObj set (eg JNI attaching threads and
2836 // if vm exit occurs during initialization). These cases can all be accounted
2837 // for such that this method never returns NULL.
2838 const char* JavaThread::get_thread_name() const {
2839 #ifdef ASSERT
2840 // early safepoints can hit while current thread does not yet have TLS
2841 if (!SafepointSynchronize::is_at_safepoint()) {
2842 Thread *cur = Thread::current();
2843 if (!(cur->is_Java_thread() && cur == this)) {
2844 // Current JavaThreads are allowed to get their own name without
2845 // the Threads_lock.
2846 assert_locked_or_safepoint(Threads_lock);
2847 }
2848 }
2849 #endif // ASSERT
2850 return get_thread_name_string();
2851 }
2852
2853 // Returns a non-NULL representation of this thread's name, or a suitable
2854 // descriptive string if there is no set name
2855 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2856 const char* name_str;
2857 oop thread_obj = threadObj();
2858 if (thread_obj != NULL) {
2859 oop name = java_lang_Thread::name(thread_obj);
2860 if (name != NULL) {
2861 if (buf == NULL) {
2862 name_str = java_lang_String::as_utf8_string(name);
2863 } else {
2864 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2865 }
2866 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2867 name_str = "<no-name - thread is attaching>";
2868 } else {
2869 name_str = Thread::name();
2870 }
2871 } else {
2872 name_str = Thread::name();
2873 }
2874 assert(name_str != NULL, "unexpected NULL thread name");
2875 return name_str;
2876 }
2877
2878
2879 const char* JavaThread::get_threadgroup_name() const {
2880 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2881 oop thread_obj = threadObj();
2882 if (thread_obj != NULL) {
2883 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2884 if (thread_group != NULL) {
2885 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2886 // ThreadGroup.name can be null
2887 if (name != NULL) {
2888 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2889 return str;
2890 }
2891 }
2892 }
2893 return NULL;
2894 }
2895
2896 const char* JavaThread::get_parent_name() const {
2897 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2898 oop thread_obj = threadObj();
2899 if (thread_obj != NULL) {
2900 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2901 if (thread_group != NULL) {
2902 oop parent = java_lang_ThreadGroup::parent(thread_group);
2903 if (parent != NULL) {
2904 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2905 // ThreadGroup.name can be null
2906 if (name != NULL) {
2907 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2908 return str;
2909 }
2910 }
2911 }
2912 }
2913 return NULL;
2914 }
2915
2916 ThreadPriority JavaThread::java_priority() const {
2917 oop thr_oop = threadObj();
2918 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2919 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2920 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2921 return priority;
2922 }
2923
2924 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2925
2926 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2927 // Link Java Thread object <-> C++ Thread
2928
2929 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2930 // and put it into a new Handle. The Handle "thread_oop" can then
2931 // be used to pass the C++ thread object to other methods.
2932
2933 // Set the Java level thread object (jthread) field of the
2934 // new thread (a JavaThread *) to C++ thread object using the
2935 // "thread_oop" handle.
2936
2937 // Set the thread field (a JavaThread *) of the
2938 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2939
2940 Handle thread_oop(Thread::current(),
2941 JNIHandles::resolve_non_null(jni_thread));
2942 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2943 "must be initialized");
2944 set_threadObj(thread_oop());
2945 java_lang_Thread::set_thread(thread_oop(), this);
2946
2947 if (prio == NoPriority) {
2948 prio = java_lang_Thread::priority(thread_oop());
2949 assert(prio != NoPriority, "A valid priority should be present");
2950 }
2951
2952 // Push the Java priority down to the native thread; needs Threads_lock
2953 Thread::set_priority(this, prio);
2954
2955 prepare_ext();
2956
2957 // Add the new thread to the Threads list and set it in motion.
2958 // We must have threads lock in order to call Threads::add.
2959 // It is crucial that we do not block before the thread is
2960 // added to the Threads list for if a GC happens, then the java_thread oop
2961 // will not be visited by GC.
2962 Threads::add(this);
2963 }
2964
2965 oop JavaThread::current_park_blocker() {
2966 // Support for JSR-166 locks
2967 oop thread_oop = threadObj();
2968 if (thread_oop != NULL &&
2969 JDK_Version::current().supports_thread_park_blocker()) {
2970 return java_lang_Thread::park_blocker(thread_oop);
2971 }
2972 return NULL;
2973 }
2974
2975
2976 void JavaThread::print_stack_on(outputStream* st) {
2977 if (!has_last_Java_frame()) return;
2978 ResourceMark rm;
2979 HandleMark hm;
2980
2981 RegisterMap reg_map(this);
2982 vframe* start_vf = last_java_vframe(®_map);
2983 int count = 0;
2984 for (vframe* f = start_vf; f; f = f->sender()) {
2985 if (f->is_java_frame()) {
2986 javaVFrame* jvf = javaVFrame::cast(f);
2987 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2988
2989 // Print out lock information
2990 if (JavaMonitorsInStackTrace) {
2991 jvf->print_lock_info_on(st, count);
2992 }
2993 } else {
2994 // Ignore non-Java frames
2995 }
2996
2997 // Bail-out case for too deep stacks
2998 count++;
2999 if (MaxJavaStackTraceDepth == count) return;
3000 }
3001 }
3002
3003
3004 // JVMTI PopFrame support
3005 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3006 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3007 if (in_bytes(size_in_bytes) != 0) {
3008 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3009 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3010 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3011 }
3012 }
3013
3014 void* JavaThread::popframe_preserved_args() {
3015 return _popframe_preserved_args;
3016 }
3017
3018 ByteSize JavaThread::popframe_preserved_args_size() {
3019 return in_ByteSize(_popframe_preserved_args_size);
3020 }
3021
3022 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3023 int sz = in_bytes(popframe_preserved_args_size());
3024 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3025 return in_WordSize(sz / wordSize);
3026 }
3027
3028 void JavaThread::popframe_free_preserved_args() {
3029 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3030 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3031 _popframe_preserved_args = NULL;
3032 _popframe_preserved_args_size = 0;
3033 }
3034
3035 #ifndef PRODUCT
3036
3037 void JavaThread::trace_frames() {
3038 tty->print_cr("[Describe stack]");
3039 int frame_no = 1;
3040 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3041 tty->print(" %d. ", frame_no++);
3042 fst.current()->print_value_on(tty, this);
3043 tty->cr();
3044 }
3045 }
3046
3047 class PrintAndVerifyOopClosure: public OopClosure {
3048 protected:
3049 template <class T> inline void do_oop_work(T* p) {
3050 oop obj = oopDesc::load_decode_heap_oop(p);
3051 if (obj == NULL) return;
3052 tty->print(INTPTR_FORMAT ": ", p);
3053 if (obj->is_oop_or_null()) {
3054 if (obj->is_objArray()) {
3055 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3056 } else {
3057 obj->print();
3058 }
3059 } else {
3060 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3061 }
3062 tty->cr();
3063 }
3064 public:
3065 virtual void do_oop(oop* p) { do_oop_work(p); }
3066 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3067 };
3068
3069
3070 static void oops_print(frame* f, const RegisterMap *map) {
3071 PrintAndVerifyOopClosure print;
3072 f->print_value();
3073 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3074 }
3075
3076 // Print our all the locations that contain oops and whether they are
3077 // valid or not. This useful when trying to find the oldest frame
3078 // where an oop has gone bad since the frame walk is from youngest to
3079 // oldest.
3080 void JavaThread::trace_oops() {
3081 tty->print_cr("[Trace oops]");
3082 frames_do(oops_print);
3083 }
3084
3085
3086 #ifdef ASSERT
3087 // Print or validate the layout of stack frames
3088 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3089 ResourceMark rm;
3090 PRESERVE_EXCEPTION_MARK;
3091 FrameValues values;
3092 int frame_no = 0;
3093 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3094 fst.current()->describe(values, ++frame_no);
3095 if (depth == frame_no) break;
3096 }
3097 if (validate_only) {
3098 values.validate();
3099 } else {
3100 tty->print_cr("[Describe stack layout]");
3101 values.print(this);
3102 }
3103 }
3104 #endif
3105
3106 void JavaThread::trace_stack_from(vframe* start_vf) {
3107 ResourceMark rm;
3108 int vframe_no = 1;
3109 for (vframe* f = start_vf; f; f = f->sender()) {
3110 if (f->is_java_frame()) {
3111 javaVFrame::cast(f)->print_activation(vframe_no++);
3112 } else {
3113 f->print();
3114 }
3115 if (vframe_no > StackPrintLimit) {
3116 tty->print_cr("...<more frames>...");
3117 return;
3118 }
3119 }
3120 }
3121
3122
3123 void JavaThread::trace_stack() {
3124 if (!has_last_Java_frame()) return;
3125 ResourceMark rm;
3126 HandleMark hm;
3127 RegisterMap reg_map(this);
3128 trace_stack_from(last_java_vframe(®_map));
3129 }
3130
3131
3132 #endif // PRODUCT
3133
3134
3135 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3136 assert(reg_map != NULL, "a map must be given");
3137 frame f = last_frame();
3138 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3139 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3140 }
3141 return NULL;
3142 }
3143
3144
3145 Klass* JavaThread::security_get_caller_class(int depth) {
3146 vframeStream vfst(this);
3147 vfst.security_get_caller_frame(depth);
3148 if (!vfst.at_end()) {
3149 return vfst.method()->method_holder();
3150 }
3151 return NULL;
3152 }
3153
3154 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3155 assert(thread->is_Compiler_thread(), "must be compiler thread");
3156 CompileBroker::compiler_thread_loop();
3157 }
3158
3159 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3160 NMethodSweeper::sweeper_loop();
3161 }
3162
3163 // Create a CompilerThread
3164 CompilerThread::CompilerThread(CompileQueue* queue,
3165 CompilerCounters* counters)
3166 : JavaThread(&compiler_thread_entry) {
3167 _env = NULL;
3168 _log = NULL;
3169 _task = NULL;
3170 _queue = queue;
3171 _counters = counters;
3172 _buffer_blob = NULL;
3173 _compiler = NULL;
3174
3175 #ifndef PRODUCT
3176 _ideal_graph_printer = NULL;
3177 #endif
3178 }
3179
3180 // Create sweeper thread
3181 CodeCacheSweeperThread::CodeCacheSweeperThread()
3182 : JavaThread(&sweeper_thread_entry) {
3183 _scanned_nmethod = NULL;
3184 }
3185 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3186 JavaThread::oops_do(f, cld_f, cf);
3187 if (_scanned_nmethod != NULL && cf != NULL) {
3188 // Safepoints can occur when the sweeper is scanning an nmethod so
3189 // process it here to make sure it isn't unloaded in the middle of
3190 // a scan.
3191 cf->do_code_blob(_scanned_nmethod);
3192 }
3193 }
3194
3195
3196 // ======= Threads ========
3197
3198 // The Threads class links together all active threads, and provides
3199 // operations over all threads. It is protected by its own Mutex
3200 // lock, which is also used in other contexts to protect thread
3201 // operations from having the thread being operated on from exiting
3202 // and going away unexpectedly (e.g., safepoint synchronization)
3203
3204 JavaThread* Threads::_thread_list = NULL;
3205 int Threads::_number_of_threads = 0;
3206 int Threads::_number_of_non_daemon_threads = 0;
3207 int Threads::_return_code = 0;
3208 int Threads::_thread_claim_parity = 0;
3209 size_t JavaThread::_stack_size_at_create = 0;
3210 #ifdef ASSERT
3211 bool Threads::_vm_complete = false;
3212 #endif
3213
3214 // All JavaThreads
3215 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3216
3217 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3218 void Threads::threads_do(ThreadClosure* tc) {
3219 assert_locked_or_safepoint(Threads_lock);
3220 // ALL_JAVA_THREADS iterates through all JavaThreads
3221 ALL_JAVA_THREADS(p) {
3222 tc->do_thread(p);
3223 }
3224 // Someday we could have a table or list of all non-JavaThreads.
3225 // For now, just manually iterate through them.
3226 tc->do_thread(VMThread::vm_thread());
3227 Universe::heap()->gc_threads_do(tc);
3228 WatcherThread *wt = WatcherThread::watcher_thread();
3229 // Strictly speaking, the following NULL check isn't sufficient to make sure
3230 // the data for WatcherThread is still valid upon being examined. However,
3231 // considering that WatchThread terminates when the VM is on the way to
3232 // exit at safepoint, the chance of the above is extremely small. The right
3233 // way to prevent termination of WatcherThread would be to acquire
3234 // Terminator_lock, but we can't do that without violating the lock rank
3235 // checking in some cases.
3236 if (wt != NULL) {
3237 tc->do_thread(wt);
3238 }
3239
3240 // If CompilerThreads ever become non-JavaThreads, add them here
3241 }
3242
3243 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3244 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3245
3246 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3247 create_vm_init_libraries();
3248 }
3249
3250 initialize_class(vmSymbols::java_lang_String(), CHECK);
3251
3252 // Initialize java_lang.System (needed before creating the thread)
3253 initialize_class(vmSymbols::java_lang_System(), CHECK);
3254 // The VM creates & returns objects of this class. Make sure it's initialized.
3255 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3256 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3257 Handle thread_group = create_initial_thread_group(CHECK);
3258 Universe::set_main_thread_group(thread_group());
3259 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3260 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3261 main_thread->set_threadObj(thread_object);
3262 // Set thread status to running since main thread has
3263 // been started and running.
3264 java_lang_Thread::set_thread_status(thread_object,
3265 java_lang_Thread::RUNNABLE);
3266
3267 // The VM preresolves methods to these classes. Make sure that they get initialized
3268 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3269 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3270 call_initializeSystemClass(CHECK);
3271
3272 // get the Java runtime name after java.lang.System is initialized
3273 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3274 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3275
3276 // an instance of OutOfMemory exception has been allocated earlier
3277 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3278 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3279 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3280 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3281 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3282 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3283 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3284 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3285 }
3286
3287 void Threads::initialize_jsr292_core_classes(TRAPS) {
3288 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3289 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3290 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3291 }
3292
3293 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3294 extern void JDK_Version_init();
3295
3296 // Preinitialize version info.
3297 VM_Version::early_initialize();
3298
3299 // Check version
3300 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3301
3302 // Initialize the output stream module
3303 ostream_init();
3304
3305 // Process java launcher properties.
3306 Arguments::process_sun_java_launcher_properties(args);
3307
3308 // Initialize the os module before using TLS
3309 os::init();
3310
3311 // Initialize system properties.
3312 Arguments::init_system_properties();
3313
3314 // So that JDK version can be used as a discriminator when parsing arguments
3315 JDK_Version_init();
3316
3317 // Update/Initialize System properties after JDK version number is known
3318 Arguments::init_version_specific_system_properties();
3319
3320 // Parse arguments
3321 jint parse_result = Arguments::parse(args);
3322 if (parse_result != JNI_OK) return parse_result;
3323
3324 os::init_before_ergo();
3325
3326 jint ergo_result = Arguments::apply_ergo();
3327 if (ergo_result != JNI_OK) return ergo_result;
3328
3329 // Final check of all ranges after ergonomics which may change values.
3330 if (!CommandLineFlagRangeList::check_ranges()) {
3331 return JNI_EINVAL;
3332 }
3333
3334 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3335 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3336 if (!constraint_result) {
3337 return JNI_EINVAL;
3338 }
3339
3340 if (PauseAtStartup) {
3341 os::pause();
3342 }
3343
3344 HOTSPOT_VM_INIT_BEGIN();
3345
3346 // Record VM creation timing statistics
3347 TraceVmCreationTime create_vm_timer;
3348 create_vm_timer.start();
3349
3350 // Timing (must come after argument parsing)
3351 TraceTime timer("Create VM", TraceStartupTime);
3352
3353 // Initialize the os module after parsing the args
3354 jint os_init_2_result = os::init_2();
3355 if (os_init_2_result != JNI_OK) return os_init_2_result;
3356
3357 jint adjust_after_os_result = Arguments::adjust_after_os();
3358 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3359
3360 // initialize TLS
3361 ThreadLocalStorage::init();
3362
3363 // Initialize output stream logging
3364 ostream_init_log();
3365
3366 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3367 // Must be before create_vm_init_agents()
3368 if (Arguments::init_libraries_at_startup()) {
3369 convert_vm_init_libraries_to_agents();
3370 }
3371
3372 // Launch -agentlib/-agentpath and converted -Xrun agents
3373 if (Arguments::init_agents_at_startup()) {
3374 create_vm_init_agents();
3375 }
3376
3377 // Initialize Threads state
3378 _thread_list = NULL;
3379 _number_of_threads = 0;
3380 _number_of_non_daemon_threads = 0;
3381
3382 // Initialize global data structures and create system classes in heap
3383 vm_init_globals();
3384
3385 // Attach the main thread to this os thread
3386 JavaThread* main_thread = new JavaThread();
3387 main_thread->set_thread_state(_thread_in_vm);
3388 // must do this before set_active_handles and initialize_thread_local_storage
3389 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3390 // change the stack size recorded here to one based on the java thread
3391 // stacksize. This adjusted size is what is used to figure the placement
3392 // of the guard pages.
3393 main_thread->record_stack_base_and_size();
3394 main_thread->initialize_thread_local_storage();
3395
3396 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3397
3398 if (!main_thread->set_as_starting_thread()) {
3399 vm_shutdown_during_initialization(
3400 "Failed necessary internal allocation. Out of swap space");
3401 delete main_thread;
3402 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3403 return JNI_ENOMEM;
3404 }
3405
3406 // Enable guard page *after* os::create_main_thread(), otherwise it would
3407 // crash Linux VM, see notes in os_linux.cpp.
3408 main_thread->create_stack_guard_pages();
3409
3410 // Initialize Java-Level synchronization subsystem
3411 ObjectMonitor::Initialize();
3412
3413 // Initialize global modules
3414 jint status = init_globals();
3415 if (status != JNI_OK) {
3416 delete main_thread;
3417 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3418 return status;
3419 }
3420
3421 // Should be done after the heap is fully created
3422 main_thread->cache_global_variables();
3423
3424 HandleMark hm;
3425
3426 { MutexLocker mu(Threads_lock);
3427 Threads::add(main_thread);
3428 }
3429
3430 // Any JVMTI raw monitors entered in onload will transition into
3431 // real raw monitor. VM is setup enough here for raw monitor enter.
3432 JvmtiExport::transition_pending_onload_raw_monitors();
3433
3434 // Create the VMThread
3435 { TraceTime timer("Start VMThread", TraceStartupTime);
3436 VMThread::create();
3437 Thread* vmthread = VMThread::vm_thread();
3438
3439 if (!os::create_thread(vmthread, os::vm_thread)) {
3440 vm_exit_during_initialization("Cannot create VM thread. "
3441 "Out of system resources.");
3442 }
3443
3444 // Wait for the VM thread to become ready, and VMThread::run to initialize
3445 // Monitors can have spurious returns, must always check another state flag
3446 {
3447 MutexLocker ml(Notify_lock);
3448 os::start_thread(vmthread);
3449 while (vmthread->active_handles() == NULL) {
3450 Notify_lock->wait();
3451 }
3452 }
3453 }
3454
3455 assert(Universe::is_fully_initialized(), "not initialized");
3456 if (VerifyDuringStartup) {
3457 // Make sure we're starting with a clean slate.
3458 VM_Verify verify_op;
3459 VMThread::execute(&verify_op);
3460 }
3461
3462 Thread* THREAD = Thread::current();
3463
3464 // At this point, the Universe is initialized, but we have not executed
3465 // any byte code. Now is a good time (the only time) to dump out the
3466 // internal state of the JVM for sharing.
3467 if (DumpSharedSpaces) {
3468 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3469 ShouldNotReachHere();
3470 }
3471
3472 // Always call even when there are not JVMTI environments yet, since environments
3473 // may be attached late and JVMTI must track phases of VM execution
3474 JvmtiExport::enter_start_phase();
3475
3476 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3477 JvmtiExport::post_vm_start();
3478
3479 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3480
3481 // We need this for ClassDataSharing - the initial vm.info property is set
3482 // with the default value of CDS "sharing" which may be reset through
3483 // command line options.
3484 reset_vm_info_property(CHECK_JNI_ERR);
3485
3486 quicken_jni_functions();
3487
3488 // Must be run after init_ft which initializes ft_enabled
3489 if (TRACE_INITIALIZE() != JNI_OK) {
3490 vm_exit_during_initialization("Failed to initialize tracing backend");
3491 }
3492
3493 // Set flag that basic initialization has completed. Used by exceptions and various
3494 // debug stuff, that does not work until all basic classes have been initialized.
3495 set_init_completed();
3496
3497 Metaspace::post_initialize();
3498
3499 HOTSPOT_VM_INIT_END();
3500
3501 // record VM initialization completion time
3502 #if INCLUDE_MANAGEMENT
3503 Management::record_vm_init_completed();
3504 #endif // INCLUDE_MANAGEMENT
3505
3506 // Compute system loader. Note that this has to occur after set_init_completed, since
3507 // valid exceptions may be thrown in the process.
3508 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3509 // set_init_completed has just been called, causing exceptions not to be shortcut
3510 // anymore. We call vm_exit_during_initialization directly instead.
3511 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3512
3513 #if INCLUDE_ALL_GCS
3514 // Support for ConcurrentMarkSweep. This should be cleaned up
3515 // and better encapsulated. The ugly nested if test would go away
3516 // once things are properly refactored. XXX YSR
3517 if (UseConcMarkSweepGC || UseG1GC) {
3518 if (UseConcMarkSweepGC) {
3519 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3520 } else {
3521 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3522 }
3523 }
3524 #endif // INCLUDE_ALL_GCS
3525
3526 // Always call even when there are not JVMTI environments yet, since environments
3527 // may be attached late and JVMTI must track phases of VM execution
3528 JvmtiExport::enter_live_phase();
3529
3530 // Signal Dispatcher needs to be started before VMInit event is posted
3531 os::signal_init();
3532
3533 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3534 if (!DisableAttachMechanism) {
3535 AttachListener::vm_start();
3536 if (StartAttachListener || AttachListener::init_at_startup()) {
3537 AttachListener::init();
3538 }
3539 }
3540
3541 // Launch -Xrun agents
3542 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3543 // back-end can launch with -Xdebug -Xrunjdwp.
3544 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3545 create_vm_init_libraries();
3546 }
3547
3548 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3549 JvmtiExport::post_vm_initialized();
3550
3551 if (TRACE_START() != JNI_OK) {
3552 vm_exit_during_initialization("Failed to start tracing backend.");
3553 }
3554
3555 if (CleanChunkPoolAsync) {
3556 Chunk::start_chunk_pool_cleaner_task();
3557 }
3558
3559 // initialize compiler(s)
3560 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3561 CompileBroker::compilation_init();
3562 #endif
3563
3564 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3565 // It is done after compilers are initialized, because otherwise compilations of
3566 // signature polymorphic MH intrinsics can be missed
3567 // (see SystemDictionary::find_method_handle_intrinsic).
3568 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3569
3570 #if INCLUDE_MANAGEMENT
3571 Management::initialize(THREAD);
3572
3573 if (HAS_PENDING_EXCEPTION) {
3574 // management agent fails to start possibly due to
3575 // configuration problem and is responsible for printing
3576 // stack trace if appropriate. Simply exit VM.
3577 vm_exit(1);
3578 }
3579 #endif // INCLUDE_MANAGEMENT
3580
3581 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3582 if (MemProfiling) MemProfiler::engage();
3583 StatSampler::engage();
3584 if (CheckJNICalls) JniPeriodicChecker::engage();
3585
3586 BiasedLocking::init();
3587
3588 #if INCLUDE_RTM_OPT
3589 RTMLockingCounters::init();
3590 #endif
3591
3592 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3593 call_postVMInitHook(THREAD);
3594 // The Java side of PostVMInitHook.run must deal with all
3595 // exceptions and provide means of diagnosis.
3596 if (HAS_PENDING_EXCEPTION) {
3597 CLEAR_PENDING_EXCEPTION;
3598 }
3599 }
3600
3601 {
3602 MutexLocker ml(PeriodicTask_lock);
3603 // Make sure the WatcherThread can be started by WatcherThread::start()
3604 // or by dynamic enrollment.
3605 WatcherThread::make_startable();
3606 // Start up the WatcherThread if there are any periodic tasks
3607 // NOTE: All PeriodicTasks should be registered by now. If they
3608 // aren't, late joiners might appear to start slowly (we might
3609 // take a while to process their first tick).
3610 if (PeriodicTask::num_tasks() > 0) {
3611 WatcherThread::start();
3612 }
3613 }
3614
3615 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3616
3617 create_vm_timer.end();
3618 #ifdef ASSERT
3619 _vm_complete = true;
3620 #endif
3621 return JNI_OK;
3622 }
3623
3624 // type for the Agent_OnLoad and JVM_OnLoad entry points
3625 extern "C" {
3626 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3627 }
3628 // Find a command line agent library and return its entry point for
3629 // -agentlib: -agentpath: -Xrun
3630 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3631 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3632 const char *on_load_symbols[],
3633 size_t num_symbol_entries) {
3634 OnLoadEntry_t on_load_entry = NULL;
3635 void *library = NULL;
3636
3637 if (!agent->valid()) {
3638 char buffer[JVM_MAXPATHLEN];
3639 char ebuf[1024] = "";
3640 const char *name = agent->name();
3641 const char *msg = "Could not find agent library ";
3642
3643 // First check to see if agent is statically linked into executable
3644 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3645 library = agent->os_lib();
3646 } else if (agent->is_absolute_path()) {
3647 library = os::dll_load(name, ebuf, sizeof ebuf);
3648 if (library == NULL) {
3649 const char *sub_msg = " in absolute path, with error: ";
3650 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3651 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3652 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3653 // If we can't find the agent, exit.
3654 vm_exit_during_initialization(buf, NULL);
3655 FREE_C_HEAP_ARRAY(char, buf);
3656 }
3657 } else {
3658 // Try to load the agent from the standard dll directory
3659 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3660 name)) {
3661 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3662 }
3663 if (library == NULL) { // Try the local directory
3664 char ns[1] = {0};
3665 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3666 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3667 }
3668 if (library == NULL) {
3669 const char *sub_msg = " on the library path, with error: ";
3670 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3671 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3672 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3673 // If we can't find the agent, exit.
3674 vm_exit_during_initialization(buf, NULL);
3675 FREE_C_HEAP_ARRAY(char, buf);
3676 }
3677 }
3678 }
3679 agent->set_os_lib(library);
3680 agent->set_valid();
3681 }
3682
3683 // Find the OnLoad function.
3684 on_load_entry =
3685 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3686 false,
3687 on_load_symbols,
3688 num_symbol_entries));
3689 return on_load_entry;
3690 }
3691
3692 // Find the JVM_OnLoad entry point
3693 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3694 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3695 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3696 }
3697
3698 // Find the Agent_OnLoad entry point
3699 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3700 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3701 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3702 }
3703
3704 // For backwards compatibility with -Xrun
3705 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3706 // treated like -agentpath:
3707 // Must be called before agent libraries are created
3708 void Threads::convert_vm_init_libraries_to_agents() {
3709 AgentLibrary* agent;
3710 AgentLibrary* next;
3711
3712 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3713 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3714 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3715
3716 // If there is an JVM_OnLoad function it will get called later,
3717 // otherwise see if there is an Agent_OnLoad
3718 if (on_load_entry == NULL) {
3719 on_load_entry = lookup_agent_on_load(agent);
3720 if (on_load_entry != NULL) {
3721 // switch it to the agent list -- so that Agent_OnLoad will be called,
3722 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3723 Arguments::convert_library_to_agent(agent);
3724 } else {
3725 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3726 }
3727 }
3728 }
3729 }
3730
3731 // Create agents for -agentlib: -agentpath: and converted -Xrun
3732 // Invokes Agent_OnLoad
3733 // Called very early -- before JavaThreads exist
3734 void Threads::create_vm_init_agents() {
3735 extern struct JavaVM_ main_vm;
3736 AgentLibrary* agent;
3737
3738 JvmtiExport::enter_onload_phase();
3739
3740 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3741 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3742
3743 if (on_load_entry != NULL) {
3744 // Invoke the Agent_OnLoad function
3745 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3746 if (err != JNI_OK) {
3747 vm_exit_during_initialization("agent library failed to init", agent->name());
3748 }
3749 } else {
3750 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3751 }
3752 }
3753 JvmtiExport::enter_primordial_phase();
3754 }
3755
3756 extern "C" {
3757 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3758 }
3759
3760 void Threads::shutdown_vm_agents() {
3761 // Send any Agent_OnUnload notifications
3762 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3763 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3764 extern struct JavaVM_ main_vm;
3765 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3766
3767 // Find the Agent_OnUnload function.
3768 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3769 os::find_agent_function(agent,
3770 false,
3771 on_unload_symbols,
3772 num_symbol_entries));
3773
3774 // Invoke the Agent_OnUnload function
3775 if (unload_entry != NULL) {
3776 JavaThread* thread = JavaThread::current();
3777 ThreadToNativeFromVM ttn(thread);
3778 HandleMark hm(thread);
3779 (*unload_entry)(&main_vm);
3780 }
3781 }
3782 }
3783
3784 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3785 // Invokes JVM_OnLoad
3786 void Threads::create_vm_init_libraries() {
3787 extern struct JavaVM_ main_vm;
3788 AgentLibrary* agent;
3789
3790 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3791 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3792
3793 if (on_load_entry != NULL) {
3794 // Invoke the JVM_OnLoad function
3795 JavaThread* thread = JavaThread::current();
3796 ThreadToNativeFromVM ttn(thread);
3797 HandleMark hm(thread);
3798 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3799 if (err != JNI_OK) {
3800 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3801 }
3802 } else {
3803 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3804 }
3805 }
3806 }
3807
3808 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3809 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3810
3811 JavaThread* java_thread = NULL;
3812 // Sequential search for now. Need to do better optimization later.
3813 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3814 oop tobj = thread->threadObj();
3815 if (!thread->is_exiting() &&
3816 tobj != NULL &&
3817 java_tid == java_lang_Thread::thread_id(tobj)) {
3818 java_thread = thread;
3819 break;
3820 }
3821 }
3822 return java_thread;
3823 }
3824
3825
3826 // Last thread running calls java.lang.Shutdown.shutdown()
3827 void JavaThread::invoke_shutdown_hooks() {
3828 HandleMark hm(this);
3829
3830 // We could get here with a pending exception, if so clear it now.
3831 if (this->has_pending_exception()) {
3832 this->clear_pending_exception();
3833 }
3834
3835 EXCEPTION_MARK;
3836 Klass* k =
3837 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3838 THREAD);
3839 if (k != NULL) {
3840 // SystemDictionary::resolve_or_null will return null if there was
3841 // an exception. If we cannot load the Shutdown class, just don't
3842 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3843 // and finalizers (if runFinalizersOnExit is set) won't be run.
3844 // Note that if a shutdown hook was registered or runFinalizersOnExit
3845 // was called, the Shutdown class would have already been loaded
3846 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3847 instanceKlassHandle shutdown_klass (THREAD, k);
3848 JavaValue result(T_VOID);
3849 JavaCalls::call_static(&result,
3850 shutdown_klass,
3851 vmSymbols::shutdown_method_name(),
3852 vmSymbols::void_method_signature(),
3853 THREAD);
3854 }
3855 CLEAR_PENDING_EXCEPTION;
3856 }
3857
3858 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3859 // the program falls off the end of main(). Another VM exit path is through
3860 // vm_exit() when the program calls System.exit() to return a value or when
3861 // there is a serious error in VM. The two shutdown paths are not exactly
3862 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3863 // and VM_Exit op at VM level.
3864 //
3865 // Shutdown sequence:
3866 // + Shutdown native memory tracking if it is on
3867 // + Wait until we are the last non-daemon thread to execute
3868 // <-- every thing is still working at this moment -->
3869 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3870 // shutdown hooks, run finalizers if finalization-on-exit
3871 // + Call before_exit(), prepare for VM exit
3872 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3873 // currently the only user of this mechanism is File.deleteOnExit())
3874 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3875 // post thread end and vm death events to JVMTI,
3876 // stop signal thread
3877 // + Call JavaThread::exit(), it will:
3878 // > release JNI handle blocks, remove stack guard pages
3879 // > remove this thread from Threads list
3880 // <-- no more Java code from this thread after this point -->
3881 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3882 // the compiler threads at safepoint
3883 // <-- do not use anything that could get blocked by Safepoint -->
3884 // + Disable tracing at JNI/JVM barriers
3885 // + Set _vm_exited flag for threads that are still running native code
3886 // + Delete this thread
3887 // + Call exit_globals()
3888 // > deletes tty
3889 // > deletes PerfMemory resources
3890 // + Return to caller
3891
3892 bool Threads::destroy_vm() {
3893 JavaThread* thread = JavaThread::current();
3894
3895 #ifdef ASSERT
3896 _vm_complete = false;
3897 #endif
3898 // Wait until we are the last non-daemon thread to execute
3899 { MutexLocker nu(Threads_lock);
3900 while (Threads::number_of_non_daemon_threads() > 1)
3901 // This wait should make safepoint checks, wait without a timeout,
3902 // and wait as a suspend-equivalent condition.
3903 //
3904 // Note: If the FlatProfiler is running and this thread is waiting
3905 // for another non-daemon thread to finish, then the FlatProfiler
3906 // is waiting for the external suspend request on this thread to
3907 // complete. wait_for_ext_suspend_completion() will eventually
3908 // timeout, but that takes time. Making this wait a suspend-
3909 // equivalent condition solves that timeout problem.
3910 //
3911 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3912 Mutex::_as_suspend_equivalent_flag);
3913 }
3914
3915 // Hang forever on exit if we are reporting an error.
3916 if (ShowMessageBoxOnError && is_error_reported()) {
3917 os::infinite_sleep();
3918 }
3919 os::wait_for_keypress_at_exit();
3920
3921 // run Java level shutdown hooks
3922 thread->invoke_shutdown_hooks();
3923
3924 before_exit(thread);
3925
3926 thread->exit(true);
3927
3928 // Stop VM thread.
3929 {
3930 // 4945125 The vm thread comes to a safepoint during exit.
3931 // GC vm_operations can get caught at the safepoint, and the
3932 // heap is unparseable if they are caught. Grab the Heap_lock
3933 // to prevent this. The GC vm_operations will not be able to
3934 // queue until after the vm thread is dead. After this point,
3935 // we'll never emerge out of the safepoint before the VM exits.
3936
3937 MutexLocker ml(Heap_lock);
3938
3939 VMThread::wait_for_vm_thread_exit();
3940 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3941 VMThread::destroy();
3942 }
3943
3944 // clean up ideal graph printers
3945 #if defined(COMPILER2) && !defined(PRODUCT)
3946 IdealGraphPrinter::clean_up();
3947 #endif
3948
3949 // Now, all Java threads are gone except daemon threads. Daemon threads
3950 // running Java code or in VM are stopped by the Safepoint. However,
3951 // daemon threads executing native code are still running. But they
3952 // will be stopped at native=>Java/VM barriers. Note that we can't
3953 // simply kill or suspend them, as it is inherently deadlock-prone.
3954
3955 #ifndef PRODUCT
3956 // disable function tracing at JNI/JVM barriers
3957 TraceJNICalls = false;
3958 TraceJVMCalls = false;
3959 TraceRuntimeCalls = false;
3960 #endif
3961
3962 VM_Exit::set_vm_exited();
3963
3964 notify_vm_shutdown();
3965
3966 delete thread;
3967
3968 // exit_globals() will delete tty
3969 exit_globals();
3970
3971 return true;
3972 }
3973
3974
3975 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3976 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3977 return is_supported_jni_version(version);
3978 }
3979
3980
3981 jboolean Threads::is_supported_jni_version(jint version) {
3982 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3983 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3984 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3985 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3986 return JNI_FALSE;
3987 }
3988
3989
3990 void Threads::add(JavaThread* p, bool force_daemon) {
3991 // The threads lock must be owned at this point
3992 assert_locked_or_safepoint(Threads_lock);
3993
3994 // See the comment for this method in thread.hpp for its purpose and
3995 // why it is called here.
3996 p->initialize_queues();
3997 p->set_next(_thread_list);
3998 _thread_list = p;
3999 _number_of_threads++;
4000 oop threadObj = p->threadObj();
4001 bool daemon = true;
4002 // Bootstrapping problem: threadObj can be null for initial
4003 // JavaThread (or for threads attached via JNI)
4004 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4005 _number_of_non_daemon_threads++;
4006 daemon = false;
4007 }
4008
4009 ThreadService::add_thread(p, daemon);
4010
4011 // Possible GC point.
4012 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4013 }
4014
4015 void Threads::remove(JavaThread* p) {
4016 // Extra scope needed for Thread_lock, so we can check
4017 // that we do not remove thread without safepoint code notice
4018 { MutexLocker ml(Threads_lock);
4019
4020 assert(includes(p), "p must be present");
4021
4022 JavaThread* current = _thread_list;
4023 JavaThread* prev = NULL;
4024
4025 while (current != p) {
4026 prev = current;
4027 current = current->next();
4028 }
4029
4030 if (prev) {
4031 prev->set_next(current->next());
4032 } else {
4033 _thread_list = p->next();
4034 }
4035 _number_of_threads--;
4036 oop threadObj = p->threadObj();
4037 bool daemon = true;
4038 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4039 _number_of_non_daemon_threads--;
4040 daemon = false;
4041
4042 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4043 // on destroy_vm will wake up.
4044 if (number_of_non_daemon_threads() == 1) {
4045 Threads_lock->notify_all();
4046 }
4047 }
4048 ThreadService::remove_thread(p, daemon);
4049
4050 // Make sure that safepoint code disregard this thread. This is needed since
4051 // the thread might mess around with locks after this point. This can cause it
4052 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4053 // of this thread since it is removed from the queue.
4054 p->set_terminated_value();
4055 } // unlock Threads_lock
4056
4057 // Since Events::log uses a lock, we grab it outside the Threads_lock
4058 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4059 }
4060
4061 // Threads_lock must be held when this is called (or must be called during a safepoint)
4062 bool Threads::includes(JavaThread* p) {
4063 assert(Threads_lock->is_locked(), "sanity check");
4064 ALL_JAVA_THREADS(q) {
4065 if (q == p) {
4066 return true;
4067 }
4068 }
4069 return false;
4070 }
4071
4072 // Operations on the Threads list for GC. These are not explicitly locked,
4073 // but the garbage collector must provide a safe context for them to run.
4074 // In particular, these things should never be called when the Threads_lock
4075 // is held by some other thread. (Note: the Safepoint abstraction also
4076 // uses the Threads_lock to guarantee this property. It also makes sure that
4077 // all threads gets blocked when exiting or starting).
4078
4079 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4080 ALL_JAVA_THREADS(p) {
4081 p->oops_do(f, cld_f, cf);
4082 }
4083 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4084 }
4085
4086 void Threads::change_thread_claim_parity() {
4087 // Set the new claim parity.
4088 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4089 "Not in range.");
4090 _thread_claim_parity++;
4091 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4092 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4093 "Not in range.");
4094 }
4095
4096 #ifdef ASSERT
4097 void Threads::assert_all_threads_claimed() {
4098 ALL_JAVA_THREADS(p) {
4099 const int thread_parity = p->oops_do_parity();
4100 assert((thread_parity == _thread_claim_parity),
4101 err_msg("Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity));
4102 }
4103 }
4104 #endif // ASSERT
4105
4106 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4107 int cp = Threads::thread_claim_parity();
4108 ALL_JAVA_THREADS(p) {
4109 if (p->claim_oops_do(is_par, cp)) {
4110 p->oops_do(f, cld_f, cf);
4111 }
4112 }
4113 VMThread* vmt = VMThread::vm_thread();
4114 if (vmt->claim_oops_do(is_par, cp)) {
4115 vmt->oops_do(f, cld_f, cf);
4116 }
4117 }
4118
4119 #if INCLUDE_ALL_GCS
4120 // Used by ParallelScavenge
4121 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4122 ALL_JAVA_THREADS(p) {
4123 q->enqueue(new ThreadRootsTask(p));
4124 }
4125 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4126 }
4127
4128 // Used by Parallel Old
4129 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4130 ALL_JAVA_THREADS(p) {
4131 q->enqueue(new ThreadRootsMarkingTask(p));
4132 }
4133 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4134 }
4135 #endif // INCLUDE_ALL_GCS
4136
4137 void Threads::nmethods_do(CodeBlobClosure* cf) {
4138 ALL_JAVA_THREADS(p) {
4139 p->nmethods_do(cf);
4140 }
4141 VMThread::vm_thread()->nmethods_do(cf);
4142 }
4143
4144 void Threads::metadata_do(void f(Metadata*)) {
4145 ALL_JAVA_THREADS(p) {
4146 p->metadata_do(f);
4147 }
4148 }
4149
4150 class ThreadHandlesClosure : public ThreadClosure {
4151 void (*_f)(Metadata*);
4152 public:
4153 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4154 virtual void do_thread(Thread* thread) {
4155 thread->metadata_handles_do(_f);
4156 }
4157 };
4158
4159 void Threads::metadata_handles_do(void f(Metadata*)) {
4160 // Only walk the Handles in Thread.
4161 ThreadHandlesClosure handles_closure(f);
4162 threads_do(&handles_closure);
4163 }
4164
4165 void Threads::deoptimized_wrt_marked_nmethods() {
4166 ALL_JAVA_THREADS(p) {
4167 p->deoptimized_wrt_marked_nmethods();
4168 }
4169 }
4170
4171
4172 // Get count Java threads that are waiting to enter the specified monitor.
4173 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4174 address monitor,
4175 bool doLock) {
4176 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4177 "must grab Threads_lock or be at safepoint");
4178 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4179
4180 int i = 0;
4181 {
4182 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4183 ALL_JAVA_THREADS(p) {
4184 if (p->is_Compiler_thread()) continue;
4185
4186 address pending = (address)p->current_pending_monitor();
4187 if (pending == monitor) { // found a match
4188 if (i < count) result->append(p); // save the first count matches
4189 i++;
4190 }
4191 }
4192 }
4193 return result;
4194 }
4195
4196
4197 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4198 bool doLock) {
4199 assert(doLock ||
4200 Threads_lock->owned_by_self() ||
4201 SafepointSynchronize::is_at_safepoint(),
4202 "must grab Threads_lock or be at safepoint");
4203
4204 // NULL owner means not locked so we can skip the search
4205 if (owner == NULL) return NULL;
4206
4207 {
4208 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4209 ALL_JAVA_THREADS(p) {
4210 // first, see if owner is the address of a Java thread
4211 if (owner == (address)p) return p;
4212 }
4213 }
4214 // Cannot assert on lack of success here since this function may be
4215 // used by code that is trying to report useful problem information
4216 // like deadlock detection.
4217 if (UseHeavyMonitors) return NULL;
4218
4219 // If we didn't find a matching Java thread and we didn't force use of
4220 // heavyweight monitors, then the owner is the stack address of the
4221 // Lock Word in the owning Java thread's stack.
4222 //
4223 JavaThread* the_owner = NULL;
4224 {
4225 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4226 ALL_JAVA_THREADS(q) {
4227 if (q->is_lock_owned(owner)) {
4228 the_owner = q;
4229 break;
4230 }
4231 }
4232 }
4233 // cannot assert on lack of success here; see above comment
4234 return the_owner;
4235 }
4236
4237 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4238 void Threads::print_on(outputStream* st, bool print_stacks,
4239 bool internal_format, bool print_concurrent_locks) {
4240 char buf[32];
4241 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4242
4243 st->print_cr("Full thread dump %s (%s %s):",
4244 Abstract_VM_Version::vm_name(),
4245 Abstract_VM_Version::vm_release(),
4246 Abstract_VM_Version::vm_info_string());
4247 st->cr();
4248
4249 #if INCLUDE_SERVICES
4250 // Dump concurrent locks
4251 ConcurrentLocksDump concurrent_locks;
4252 if (print_concurrent_locks) {
4253 concurrent_locks.dump_at_safepoint();
4254 }
4255 #endif // INCLUDE_SERVICES
4256
4257 ALL_JAVA_THREADS(p) {
4258 ResourceMark rm;
4259 p->print_on(st);
4260 if (print_stacks) {
4261 if (internal_format) {
4262 p->trace_stack();
4263 } else {
4264 p->print_stack_on(st);
4265 }
4266 }
4267 st->cr();
4268 #if INCLUDE_SERVICES
4269 if (print_concurrent_locks) {
4270 concurrent_locks.print_locks_on(p, st);
4271 }
4272 #endif // INCLUDE_SERVICES
4273 }
4274
4275 VMThread::vm_thread()->print_on(st);
4276 st->cr();
4277 Universe::heap()->print_gc_threads_on(st);
4278 WatcherThread* wt = WatcherThread::watcher_thread();
4279 if (wt != NULL) {
4280 wt->print_on(st);
4281 st->cr();
4282 }
4283 CompileBroker::print_compiler_threads_on(st);
4284 st->flush();
4285 }
4286
4287 // Threads::print_on_error() is called by fatal error handler. It's possible
4288 // that VM is not at safepoint and/or current thread is inside signal handler.
4289 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4290 // memory (even in resource area), it might deadlock the error handler.
4291 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4292 int buflen) {
4293 bool found_current = false;
4294 st->print_cr("Java Threads: ( => current thread )");
4295 ALL_JAVA_THREADS(thread) {
4296 bool is_current = (current == thread);
4297 found_current = found_current || is_current;
4298
4299 st->print("%s", is_current ? "=>" : " ");
4300
4301 st->print(PTR_FORMAT, thread);
4302 st->print(" ");
4303 thread->print_on_error(st, buf, buflen);
4304 st->cr();
4305 }
4306 st->cr();
4307
4308 st->print_cr("Other Threads:");
4309 if (VMThread::vm_thread()) {
4310 bool is_current = (current == VMThread::vm_thread());
4311 found_current = found_current || is_current;
4312 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4313
4314 st->print(PTR_FORMAT, VMThread::vm_thread());
4315 st->print(" ");
4316 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4317 st->cr();
4318 }
4319 WatcherThread* wt = WatcherThread::watcher_thread();
4320 if (wt != NULL) {
4321 bool is_current = (current == wt);
4322 found_current = found_current || is_current;
4323 st->print("%s", is_current ? "=>" : " ");
4324
4325 st->print(PTR_FORMAT, wt);
4326 st->print(" ");
4327 wt->print_on_error(st, buf, buflen);
4328 st->cr();
4329 }
4330 if (!found_current) {
4331 st->cr();
4332 st->print("=>" PTR_FORMAT " (exited) ", current);
4333 current->print_on_error(st, buf, buflen);
4334 st->cr();
4335 }
4336 }
4337
4338 // Internal SpinLock and Mutex
4339 // Based on ParkEvent
4340
4341 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4342 //
4343 // We employ SpinLocks _only for low-contention, fixed-length
4344 // short-duration critical sections where we're concerned
4345 // about native mutex_t or HotSpot Mutex:: latency.
4346 // The mux construct provides a spin-then-block mutual exclusion
4347 // mechanism.
4348 //
4349 // Testing has shown that contention on the ListLock guarding gFreeList
4350 // is common. If we implement ListLock as a simple SpinLock it's common
4351 // for the JVM to devolve to yielding with little progress. This is true
4352 // despite the fact that the critical sections protected by ListLock are
4353 // extremely short.
4354 //
4355 // TODO-FIXME: ListLock should be of type SpinLock.
4356 // We should make this a 1st-class type, integrated into the lock
4357 // hierarchy as leaf-locks. Critically, the SpinLock structure
4358 // should have sufficient padding to avoid false-sharing and excessive
4359 // cache-coherency traffic.
4360
4361
4362 typedef volatile int SpinLockT;
4363
4364 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4365 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4366 return; // normal fast-path return
4367 }
4368
4369 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4370 TEVENT(SpinAcquire - ctx);
4371 int ctr = 0;
4372 int Yields = 0;
4373 for (;;) {
4374 while (*adr != 0) {
4375 ++ctr;
4376 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4377 if (Yields > 5) {
4378 os::naked_short_sleep(1);
4379 } else {
4380 os::naked_yield();
4381 ++Yields;
4382 }
4383 } else {
4384 SpinPause();
4385 }
4386 }
4387 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4388 }
4389 }
4390
4391 void Thread::SpinRelease(volatile int * adr) {
4392 assert(*adr != 0, "invariant");
4393 OrderAccess::fence(); // guarantee at least release consistency.
4394 // Roach-motel semantics.
4395 // It's safe if subsequent LDs and STs float "up" into the critical section,
4396 // but prior LDs and STs within the critical section can't be allowed
4397 // to reorder or float past the ST that releases the lock.
4398 // Loads and stores in the critical section - which appear in program
4399 // order before the store that releases the lock - must also appear
4400 // before the store that releases the lock in memory visibility order.
4401 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4402 // the ST of 0 into the lock-word which releases the lock, so fence
4403 // more than covers this on all platforms.
4404 *adr = 0;
4405 }
4406
4407 // muxAcquire and muxRelease:
4408 //
4409 // * muxAcquire and muxRelease support a single-word lock-word construct.
4410 // The LSB of the word is set IFF the lock is held.
4411 // The remainder of the word points to the head of a singly-linked list
4412 // of threads blocked on the lock.
4413 //
4414 // * The current implementation of muxAcquire-muxRelease uses its own
4415 // dedicated Thread._MuxEvent instance. If we're interested in
4416 // minimizing the peak number of extant ParkEvent instances then
4417 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4418 // as certain invariants were satisfied. Specifically, care would need
4419 // to be taken with regards to consuming unpark() "permits".
4420 // A safe rule of thumb is that a thread would never call muxAcquire()
4421 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4422 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4423 // consume an unpark() permit intended for monitorenter, for instance.
4424 // One way around this would be to widen the restricted-range semaphore
4425 // implemented in park(). Another alternative would be to provide
4426 // multiple instances of the PlatformEvent() for each thread. One
4427 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4428 //
4429 // * Usage:
4430 // -- Only as leaf locks
4431 // -- for short-term locking only as muxAcquire does not perform
4432 // thread state transitions.
4433 //
4434 // Alternatives:
4435 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4436 // but with parking or spin-then-park instead of pure spinning.
4437 // * Use Taura-Oyama-Yonenzawa locks.
4438 // * It's possible to construct a 1-0 lock if we encode the lockword as
4439 // (List,LockByte). Acquire will CAS the full lockword while Release
4440 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4441 // acquiring threads use timers (ParkTimed) to detect and recover from
4442 // the stranding window. Thread/Node structures must be aligned on 256-byte
4443 // boundaries by using placement-new.
4444 // * Augment MCS with advisory back-link fields maintained with CAS().
4445 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4446 // The validity of the backlinks must be ratified before we trust the value.
4447 // If the backlinks are invalid the exiting thread must back-track through the
4448 // the forward links, which are always trustworthy.
4449 // * Add a successor indication. The LockWord is currently encoded as
4450 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4451 // to provide the usual futile-wakeup optimization.
4452 // See RTStt for details.
4453 // * Consider schedctl.sc_nopreempt to cover the critical section.
4454 //
4455
4456
4457 typedef volatile intptr_t MutexT; // Mux Lock-word
4458 enum MuxBits { LOCKBIT = 1 };
4459
4460 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4461 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4462 if (w == 0) return;
4463 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4464 return;
4465 }
4466
4467 TEVENT(muxAcquire - Contention);
4468 ParkEvent * const Self = Thread::current()->_MuxEvent;
4469 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4470 for (;;) {
4471 int its = (os::is_MP() ? 100 : 0) + 1;
4472
4473 // Optional spin phase: spin-then-park strategy
4474 while (--its >= 0) {
4475 w = *Lock;
4476 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4477 return;
4478 }
4479 }
4480
4481 Self->reset();
4482 Self->OnList = intptr_t(Lock);
4483 // The following fence() isn't _strictly necessary as the subsequent
4484 // CAS() both serializes execution and ratifies the fetched *Lock value.
4485 OrderAccess::fence();
4486 for (;;) {
4487 w = *Lock;
4488 if ((w & LOCKBIT) == 0) {
4489 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4490 Self->OnList = 0; // hygiene - allows stronger asserts
4491 return;
4492 }
4493 continue; // Interference -- *Lock changed -- Just retry
4494 }
4495 assert(w & LOCKBIT, "invariant");
4496 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4497 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4498 }
4499
4500 while (Self->OnList != 0) {
4501 Self->park();
4502 }
4503 }
4504 }
4505
4506 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4507 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4508 if (w == 0) return;
4509 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4510 return;
4511 }
4512
4513 TEVENT(muxAcquire - Contention);
4514 ParkEvent * ReleaseAfter = NULL;
4515 if (ev == NULL) {
4516 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4517 }
4518 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4519 for (;;) {
4520 guarantee(ev->OnList == 0, "invariant");
4521 int its = (os::is_MP() ? 100 : 0) + 1;
4522
4523 // Optional spin phase: spin-then-park strategy
4524 while (--its >= 0) {
4525 w = *Lock;
4526 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4527 if (ReleaseAfter != NULL) {
4528 ParkEvent::Release(ReleaseAfter);
4529 }
4530 return;
4531 }
4532 }
4533
4534 ev->reset();
4535 ev->OnList = intptr_t(Lock);
4536 // The following fence() isn't _strictly necessary as the subsequent
4537 // CAS() both serializes execution and ratifies the fetched *Lock value.
4538 OrderAccess::fence();
4539 for (;;) {
4540 w = *Lock;
4541 if ((w & LOCKBIT) == 0) {
4542 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4543 ev->OnList = 0;
4544 // We call ::Release while holding the outer lock, thus
4545 // artificially lengthening the critical section.
4546 // Consider deferring the ::Release() until the subsequent unlock(),
4547 // after we've dropped the outer lock.
4548 if (ReleaseAfter != NULL) {
4549 ParkEvent::Release(ReleaseAfter);
4550 }
4551 return;
4552 }
4553 continue; // Interference -- *Lock changed -- Just retry
4554 }
4555 assert(w & LOCKBIT, "invariant");
4556 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4557 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4558 }
4559
4560 while (ev->OnList != 0) {
4561 ev->park();
4562 }
4563 }
4564 }
4565
4566 // Release() must extract a successor from the list and then wake that thread.
4567 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4568 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4569 // Release() would :
4570 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4571 // (B) Extract a successor from the private list "in-hand"
4572 // (C) attempt to CAS() the residual back into *Lock over null.
4573 // If there were any newly arrived threads and the CAS() would fail.
4574 // In that case Release() would detach the RATs, re-merge the list in-hand
4575 // with the RATs and repeat as needed. Alternately, Release() might
4576 // detach and extract a successor, but then pass the residual list to the wakee.
4577 // The wakee would be responsible for reattaching and remerging before it
4578 // competed for the lock.
4579 //
4580 // Both "pop" and DMR are immune from ABA corruption -- there can be
4581 // multiple concurrent pushers, but only one popper or detacher.
4582 // This implementation pops from the head of the list. This is unfair,
4583 // but tends to provide excellent throughput as hot threads remain hot.
4584 // (We wake recently run threads first).
4585 //
4586 // All paths through muxRelease() will execute a CAS.
4587 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4588 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4589 // executed within the critical section are complete and globally visible before the
4590 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4591 void Thread::muxRelease(volatile intptr_t * Lock) {
4592 for (;;) {
4593 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4594 assert(w & LOCKBIT, "invariant");
4595 if (w == LOCKBIT) return;
4596 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4597 assert(List != NULL, "invariant");
4598 assert(List->OnList == intptr_t(Lock), "invariant");
4599 ParkEvent * const nxt = List->ListNext;
4600 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4601
4602 // The following CAS() releases the lock and pops the head element.
4603 // The CAS() also ratifies the previously fetched lock-word value.
4604 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4605 continue;
4606 }
4607 List->OnList = 0;
4608 OrderAccess::fence();
4609 List->unpark();
4610 return;
4611 }
4612 }
4613
4614
4615 void Threads::verify() {
4616 ALL_JAVA_THREADS(p) {
4617 p->verify();
4618 }
4619 VMThread* thread = VMThread::vm_thread();
4620 if (thread != NULL) thread->verify();
4621 }