1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/codeCacheExtensions.hpp"
32 #include "code/scopeDesc.hpp"
33 #include "compiler/compileBroker.hpp"
34 #include "gc/shared/gcLocker.inline.hpp"
35 #include "gc/shared/workgroup.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "interpreter/linkResolver.hpp"
38 #include "interpreter/oopMapCache.hpp"
39 #include "jvmtifiles/jvmtiEnv.hpp"
40 #include "logging/logConfiguration.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 _vm_operation_started_count = 0;
224 _vm_operation_completed_count = 0;
225 _current_pending_monitor = NULL;
226 _current_pending_monitor_is_from_java = true;
227 _current_waiting_monitor = NULL;
228 _num_nested_signal = 0;
229 omFreeList = NULL;
230 omFreeCount = 0;
231 omFreeProvision = 32;
232 omInUseList = NULL;
233 omInUseCount = 0;
234
235 #ifdef ASSERT
236 _visited_for_critical_count = false;
237 #endif
238
239 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
240 Monitor::_safepoint_check_sometimes);
241 _suspend_flags = 0;
242
243 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
244 _hashStateX = os::random();
245 _hashStateY = 842502087;
246 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
247 _hashStateW = 273326509;
248
249 _OnTrap = 0;
250 _schedctl = NULL;
251 _Stalled = 0;
252 _TypeTag = 0x2BAD;
253
254 // Many of the following fields are effectively final - immutable
255 // Note that nascent threads can't use the Native Monitor-Mutex
256 // construct until the _MutexEvent is initialized ...
257 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
258 // we might instead use a stack of ParkEvents that we could provision on-demand.
259 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
260 // and ::Release()
261 _ParkEvent = ParkEvent::Allocate(this);
262 _SleepEvent = ParkEvent::Allocate(this);
263 _MutexEvent = ParkEvent::Allocate(this);
264 _MuxEvent = ParkEvent::Allocate(this);
265
266 #ifdef CHECK_UNHANDLED_OOPS
267 if (CheckUnhandledOops) {
268 _unhandled_oops = new UnhandledOops(this);
269 }
270 #endif // CHECK_UNHANDLED_OOPS
271 #ifdef ASSERT
272 if (UseBiasedLocking) {
273 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
274 assert(this == _real_malloc_address ||
275 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
276 "bug in forced alignment of thread objects");
277 }
278 #endif // ASSERT
279 }
280
281 // Non-inlined version to be used where thread.inline.hpp shouldn't be included.
282 Thread* Thread::current_noinline() {
283 return Thread::current();
284 }
285
286 void Thread::initialize_thread_local_storage() {
287 // Note: Make sure this method only calls
288 // non-blocking operations. Otherwise, it might not work
289 // with the thread-startup/safepoint interaction.
290
291 // During Java thread startup, safepoint code should allow this
292 // method to complete because it may need to allocate memory to
293 // store information for the new thread.
294
295 // initialize structure dependent on thread local storage
296 ThreadLocalStorage::set_thread(this);
297 }
298
299 void Thread::record_stack_base_and_size() {
300 set_stack_base(os::current_stack_base());
301 set_stack_size(os::current_stack_size());
302 if (is_Java_thread()) {
303 ((JavaThread*) this)->set_stack_overflow_limit();
304 }
305 // CR 7190089: on Solaris, primordial thread's stack is adjusted
306 // in initialize_thread(). Without the adjustment, stack size is
307 // incorrect if stack is set to unlimited (ulimit -s unlimited).
308 // So far, only Solaris has real implementation of initialize_thread().
309 //
310 // set up any platform-specific state.
311 os::initialize_thread(this);
312
313 #if INCLUDE_NMT
314 // record thread's native stack, stack grows downward
315 address stack_low_addr = stack_base() - stack_size();
316 MemTracker::record_thread_stack(stack_low_addr, stack_size());
317 #endif // INCLUDE_NMT
318 }
319
320
321 Thread::~Thread() {
322 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
323 ObjectSynchronizer::omFlush(this);
324
325 EVENT_THREAD_DESTRUCT(this);
326
327 // stack_base can be NULL if the thread is never started or exited before
328 // record_stack_base_and_size called. Although, we would like to ensure
329 // that all started threads do call record_stack_base_and_size(), there is
330 // not proper way to enforce that.
331 #if INCLUDE_NMT
332 if (_stack_base != NULL) {
333 address low_stack_addr = stack_base() - stack_size();
334 MemTracker::release_thread_stack(low_stack_addr, stack_size());
335 #ifdef ASSERT
336 set_stack_base(NULL);
337 #endif
338 }
339 #endif // INCLUDE_NMT
340
341 // deallocate data structures
342 delete resource_area();
343 // since the handle marks are using the handle area, we have to deallocated the root
344 // handle mark before deallocating the thread's handle area,
345 assert(last_handle_mark() != NULL, "check we have an element");
346 delete last_handle_mark();
347 assert(last_handle_mark() == NULL, "check we have reached the end");
348
349 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
350 // We NULL out the fields for good hygiene.
351 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
352 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
353 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
354 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
355
356 delete handle_area();
357 delete metadata_handles();
358
359 // osthread() can be NULL, if creation of thread failed.
360 if (osthread() != NULL) os::free_thread(osthread());
361
362 delete _SR_lock;
363
364 // clear thread local storage if the Thread is deleting itself
365 if (this == Thread::current()) {
366 ThreadLocalStorage::set_thread(NULL);
367 } else {
368 // In the case where we're not the current thread, invalidate all the
369 // caches in case some code tries to get the current thread or the
370 // thread that was destroyed, and gets stale information.
371 ThreadLocalStorage::invalidate_all();
372 }
373 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
374 }
375
376 // NOTE: dummy function for assertion purpose.
377 void Thread::run() {
378 ShouldNotReachHere();
379 }
380
381 #ifdef ASSERT
382 // Private method to check for dangling thread pointer
383 void check_for_dangling_thread_pointer(Thread *thread) {
384 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
385 "possibility of dangling Thread pointer");
386 }
387 #endif
388
389 ThreadPriority Thread::get_priority(const Thread* const thread) {
390 ThreadPriority priority;
391 // Can return an error!
392 (void)os::get_priority(thread, priority);
393 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
394 return priority;
395 }
396
397 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
398 debug_only(check_for_dangling_thread_pointer(thread);)
399 // Can return an error!
400 (void)os::set_priority(thread, priority);
401 }
402
403
404 void Thread::start(Thread* thread) {
405 // Start is different from resume in that its safety is guaranteed by context or
406 // being called from a Java method synchronized on the Thread object.
407 if (!DisableStartThread) {
408 if (thread->is_Java_thread()) {
409 // Initialize the thread state to RUNNABLE before starting this thread.
410 // Can not set it after the thread started because we do not know the
411 // exact thread state at that time. It could be in MONITOR_WAIT or
412 // in SLEEPING or some other state.
413 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
414 java_lang_Thread::RUNNABLE);
415 }
416 os::start_thread(thread);
417 }
418 }
419
420 // Enqueue a VM_Operation to do the job for us - sometime later
421 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
422 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
423 VMThread::execute(vm_stop);
424 }
425
426
427 // Check if an external suspend request has completed (or has been
428 // cancelled). Returns true if the thread is externally suspended and
429 // false otherwise.
430 //
431 // The bits parameter returns information about the code path through
432 // the routine. Useful for debugging:
433 //
434 // set in is_ext_suspend_completed():
435 // 0x00000001 - routine was entered
436 // 0x00000010 - routine return false at end
437 // 0x00000100 - thread exited (return false)
438 // 0x00000200 - suspend request cancelled (return false)
439 // 0x00000400 - thread suspended (return true)
440 // 0x00001000 - thread is in a suspend equivalent state (return true)
441 // 0x00002000 - thread is native and walkable (return true)
442 // 0x00004000 - thread is native_trans and walkable (needed retry)
443 //
444 // set in wait_for_ext_suspend_completion():
445 // 0x00010000 - routine was entered
446 // 0x00020000 - suspend request cancelled before loop (return false)
447 // 0x00040000 - thread suspended before loop (return true)
448 // 0x00080000 - suspend request cancelled in loop (return false)
449 // 0x00100000 - thread suspended in loop (return true)
450 // 0x00200000 - suspend not completed during retry loop (return false)
451
452 // Helper class for tracing suspend wait debug bits.
453 //
454 // 0x00000100 indicates that the target thread exited before it could
455 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
456 // 0x00080000 each indicate a cancelled suspend request so they don't
457 // count as wait failures either.
458 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
459
460 class TraceSuspendDebugBits : public StackObj {
461 private:
462 JavaThread * jt;
463 bool is_wait;
464 bool called_by_wait; // meaningful when !is_wait
465 uint32_t * bits;
466
467 public:
468 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
469 uint32_t *_bits) {
470 jt = _jt;
471 is_wait = _is_wait;
472 called_by_wait = _called_by_wait;
473 bits = _bits;
474 }
475
476 ~TraceSuspendDebugBits() {
477 if (!is_wait) {
478 #if 1
479 // By default, don't trace bits for is_ext_suspend_completed() calls.
480 // That trace is very chatty.
481 return;
482 #else
483 if (!called_by_wait) {
484 // If tracing for is_ext_suspend_completed() is enabled, then only
485 // trace calls to it from wait_for_ext_suspend_completion()
486 return;
487 }
488 #endif
489 }
490
491 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
492 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
493 MutexLocker ml(Threads_lock); // needed for get_thread_name()
494 ResourceMark rm;
495
496 tty->print_cr(
497 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
498 jt->get_thread_name(), *bits);
499
500 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
501 }
502 }
503 }
504 };
505 #undef DEBUG_FALSE_BITS
506
507
508 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
509 uint32_t *bits) {
510 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
511
512 bool did_trans_retry = false; // only do thread_in_native_trans retry once
513 bool do_trans_retry; // flag to force the retry
514
515 *bits |= 0x00000001;
516
517 do {
518 do_trans_retry = false;
519
520 if (is_exiting()) {
521 // Thread is in the process of exiting. This is always checked
522 // first to reduce the risk of dereferencing a freed JavaThread.
523 *bits |= 0x00000100;
524 return false;
525 }
526
527 if (!is_external_suspend()) {
528 // Suspend request is cancelled. This is always checked before
529 // is_ext_suspended() to reduce the risk of a rogue resume
530 // confusing the thread that made the suspend request.
531 *bits |= 0x00000200;
532 return false;
533 }
534
535 if (is_ext_suspended()) {
536 // thread is suspended
537 *bits |= 0x00000400;
538 return true;
539 }
540
541 // Now that we no longer do hard suspends of threads running
542 // native code, the target thread can be changing thread state
543 // while we are in this routine:
544 //
545 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
546 //
547 // We save a copy of the thread state as observed at this moment
548 // and make our decision about suspend completeness based on the
549 // copy. This closes the race where the thread state is seen as
550 // _thread_in_native_trans in the if-thread_blocked check, but is
551 // seen as _thread_blocked in if-thread_in_native_trans check.
552 JavaThreadState save_state = thread_state();
553
554 if (save_state == _thread_blocked && is_suspend_equivalent()) {
555 // If the thread's state is _thread_blocked and this blocking
556 // condition is known to be equivalent to a suspend, then we can
557 // consider the thread to be externally suspended. This means that
558 // the code that sets _thread_blocked has been modified to do
559 // self-suspension if the blocking condition releases. We also
560 // used to check for CONDVAR_WAIT here, but that is now covered by
561 // the _thread_blocked with self-suspension check.
562 //
563 // Return true since we wouldn't be here unless there was still an
564 // external suspend request.
565 *bits |= 0x00001000;
566 return true;
567 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
568 // Threads running native code will self-suspend on native==>VM/Java
569 // transitions. If its stack is walkable (should always be the case
570 // unless this function is called before the actual java_suspend()
571 // call), then the wait is done.
572 *bits |= 0x00002000;
573 return true;
574 } else if (!called_by_wait && !did_trans_retry &&
575 save_state == _thread_in_native_trans &&
576 frame_anchor()->walkable()) {
577 // The thread is transitioning from thread_in_native to another
578 // thread state. check_safepoint_and_suspend_for_native_trans()
579 // will force the thread to self-suspend. If it hasn't gotten
580 // there yet we may have caught the thread in-between the native
581 // code check above and the self-suspend. Lucky us. If we were
582 // called by wait_for_ext_suspend_completion(), then it
583 // will be doing the retries so we don't have to.
584 //
585 // Since we use the saved thread state in the if-statement above,
586 // there is a chance that the thread has already transitioned to
587 // _thread_blocked by the time we get here. In that case, we will
588 // make a single unnecessary pass through the logic below. This
589 // doesn't hurt anything since we still do the trans retry.
590
591 *bits |= 0x00004000;
592
593 // Once the thread leaves thread_in_native_trans for another
594 // thread state, we break out of this retry loop. We shouldn't
595 // need this flag to prevent us from getting back here, but
596 // sometimes paranoia is good.
597 did_trans_retry = true;
598
599 // We wait for the thread to transition to a more usable state.
600 for (int i = 1; i <= SuspendRetryCount; i++) {
601 // We used to do an "os::yield_all(i)" call here with the intention
602 // that yielding would increase on each retry. However, the parameter
603 // is ignored on Linux which means the yield didn't scale up. Waiting
604 // on the SR_lock below provides a much more predictable scale up for
605 // the delay. It also provides a simple/direct point to check for any
606 // safepoint requests from the VMThread
607
608 // temporarily drops SR_lock while doing wait with safepoint check
609 // (if we're a JavaThread - the WatcherThread can also call this)
610 // and increase delay with each retry
611 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
612
613 // check the actual thread state instead of what we saved above
614 if (thread_state() != _thread_in_native_trans) {
615 // the thread has transitioned to another thread state so
616 // try all the checks (except this one) one more time.
617 do_trans_retry = true;
618 break;
619 }
620 } // end retry loop
621
622
623 }
624 } while (do_trans_retry);
625
626 *bits |= 0x00000010;
627 return false;
628 }
629
630 // Wait for an external suspend request to complete (or be cancelled).
631 // Returns true if the thread is externally suspended and false otherwise.
632 //
633 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
634 uint32_t *bits) {
635 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
636 false /* !called_by_wait */, bits);
637
638 // local flag copies to minimize SR_lock hold time
639 bool is_suspended;
640 bool pending;
641 uint32_t reset_bits;
642
643 // set a marker so is_ext_suspend_completed() knows we are the caller
644 *bits |= 0x00010000;
645
646 // We use reset_bits to reinitialize the bits value at the top of
647 // each retry loop. This allows the caller to make use of any
648 // unused bits for their own marking purposes.
649 reset_bits = *bits;
650
651 {
652 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
653 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
654 delay, bits);
655 pending = is_external_suspend();
656 }
657 // must release SR_lock to allow suspension to complete
658
659 if (!pending) {
660 // A cancelled suspend request is the only false return from
661 // is_ext_suspend_completed() that keeps us from entering the
662 // retry loop.
663 *bits |= 0x00020000;
664 return false;
665 }
666
667 if (is_suspended) {
668 *bits |= 0x00040000;
669 return true;
670 }
671
672 for (int i = 1; i <= retries; i++) {
673 *bits = reset_bits; // reinit to only track last retry
674
675 // We used to do an "os::yield_all(i)" call here with the intention
676 // that yielding would increase on each retry. However, the parameter
677 // is ignored on Linux which means the yield didn't scale up. Waiting
678 // on the SR_lock below provides a much more predictable scale up for
679 // the delay. It also provides a simple/direct point to check for any
680 // safepoint requests from the VMThread
681
682 {
683 MutexLocker ml(SR_lock());
684 // wait with safepoint check (if we're a JavaThread - the WatcherThread
685 // can also call this) and increase delay with each retry
686 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
687
688 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
689 delay, bits);
690
691 // It is possible for the external suspend request to be cancelled
692 // (by a resume) before the actual suspend operation is completed.
693 // Refresh our local copy to see if we still need to wait.
694 pending = is_external_suspend();
695 }
696
697 if (!pending) {
698 // A cancelled suspend request is the only false return from
699 // is_ext_suspend_completed() that keeps us from staying in the
700 // retry loop.
701 *bits |= 0x00080000;
702 return false;
703 }
704
705 if (is_suspended) {
706 *bits |= 0x00100000;
707 return true;
708 }
709 } // end retry loop
710
711 // thread did not suspend after all our retries
712 *bits |= 0x00200000;
713 return false;
714 }
715
716 #ifndef PRODUCT
717 void JavaThread::record_jump(address target, address instr, const char* file,
718 int line) {
719
720 // This should not need to be atomic as the only way for simultaneous
721 // updates is via interrupts. Even then this should be rare or non-existent
722 // and we don't care that much anyway.
723
724 int index = _jmp_ring_index;
725 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
726 _jmp_ring[index]._target = (intptr_t) target;
727 _jmp_ring[index]._instruction = (intptr_t) instr;
728 _jmp_ring[index]._file = file;
729 _jmp_ring[index]._line = line;
730 }
731 #endif // PRODUCT
732
733 // Called by flat profiler
734 // Callers have already called wait_for_ext_suspend_completion
735 // The assertion for that is currently too complex to put here:
736 bool JavaThread::profile_last_Java_frame(frame* _fr) {
737 bool gotframe = false;
738 // self suspension saves needed state.
739 if (has_last_Java_frame() && _anchor.walkable()) {
740 *_fr = pd_last_frame();
741 gotframe = true;
742 }
743 return gotframe;
744 }
745
746 void Thread::interrupt(Thread* thread) {
747 debug_only(check_for_dangling_thread_pointer(thread);)
748 os::interrupt(thread);
749 }
750
751 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
752 debug_only(check_for_dangling_thread_pointer(thread);)
753 // Note: If clear_interrupted==false, this simply fetches and
754 // returns the value of the field osthread()->interrupted().
755 return os::is_interrupted(thread, clear_interrupted);
756 }
757
758
759 // GC Support
760 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
761 jint thread_parity = _oops_do_parity;
762 if (thread_parity != strong_roots_parity) {
763 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
764 if (res == thread_parity) {
765 return true;
766 } else {
767 guarantee(res == strong_roots_parity, "Or else what?");
768 return false;
769 }
770 }
771 return false;
772 }
773
774 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
775 active_handles()->oops_do(f);
776 // Do oop for ThreadShadow
777 f->do_oop((oop*)&_pending_exception);
778 handle_area()->oops_do(f);
779 }
780
781 void Thread::nmethods_do(CodeBlobClosure* cf) {
782 // no nmethods in a generic thread...
783 }
784
785 void Thread::metadata_handles_do(void f(Metadata*)) {
786 // Only walk the Handles in Thread.
787 if (metadata_handles() != NULL) {
788 for (int i = 0; i< metadata_handles()->length(); i++) {
789 f(metadata_handles()->at(i));
790 }
791 }
792 }
793
794 void Thread::print_on(outputStream* st) const {
795 // get_priority assumes osthread initialized
796 if (osthread() != NULL) {
797 int os_prio;
798 if (os::get_native_priority(this, &os_prio) == OS_OK) {
799 st->print("os_prio=%d ", os_prio);
800 }
801 st->print("tid=" INTPTR_FORMAT " ", this);
802 ext().print_on(st);
803 osthread()->print_on(st);
804 }
805 debug_only(if (WizardMode) print_owned_locks_on(st);)
806 }
807
808 // Thread::print_on_error() is called by fatal error handler. Don't use
809 // any lock or allocate memory.
810 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
811 if (is_VM_thread()) st->print("VMThread");
812 else if (is_Compiler_thread()) st->print("CompilerThread");
813 else if (is_Java_thread()) st->print("JavaThread");
814 else if (is_GC_task_thread()) st->print("GCTaskThread");
815 else if (is_Watcher_thread()) st->print("WatcherThread");
816 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
817 else st->print("Thread");
818
819 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
820 _stack_base - _stack_size, _stack_base);
821
822 if (osthread()) {
823 st->print(" [id=%d]", osthread()->thread_id());
824 }
825 }
826
827 #ifdef ASSERT
828 void Thread::print_owned_locks_on(outputStream* st) const {
829 Monitor *cur = _owned_locks;
830 if (cur == NULL) {
831 st->print(" (no locks) ");
832 } else {
833 st->print_cr(" Locks owned:");
834 while (cur) {
835 cur->print_on(st);
836 cur = cur->next();
837 }
838 }
839 }
840
841 static int ref_use_count = 0;
842
843 bool Thread::owns_locks_but_compiled_lock() const {
844 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
845 if (cur != Compile_lock) return true;
846 }
847 return false;
848 }
849
850
851 #endif
852
853 #ifndef PRODUCT
854
855 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
856 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
857 // no threads which allow_vm_block's are held
858 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
859 // Check if current thread is allowed to block at a safepoint
860 if (!(_allow_safepoint_count == 0)) {
861 fatal("Possible safepoint reached by thread that does not allow it");
862 }
863 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
864 fatal("LEAF method calling lock?");
865 }
866
867 #ifdef ASSERT
868 if (potential_vm_operation && is_Java_thread()
869 && !Universe::is_bootstrapping()) {
870 // Make sure we do not hold any locks that the VM thread also uses.
871 // This could potentially lead to deadlocks
872 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
873 // Threads_lock is special, since the safepoint synchronization will not start before this is
874 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
875 // since it is used to transfer control between JavaThreads and the VMThread
876 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
877 if ((cur->allow_vm_block() &&
878 cur != Threads_lock &&
879 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
880 cur != VMOperationRequest_lock &&
881 cur != VMOperationQueue_lock) ||
882 cur->rank() == Mutex::special) {
883 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
884 }
885 }
886 }
887
888 if (GCALotAtAllSafepoints) {
889 // We could enter a safepoint here and thus have a gc
890 InterfaceSupport::check_gc_alot();
891 }
892 #endif
893 }
894 #endif
895
896 bool Thread::is_in_stack(address adr) const {
897 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
898 address end = os::current_stack_pointer();
899 // Allow non Java threads to call this without stack_base
900 if (_stack_base == NULL) return true;
901 if (stack_base() >= adr && adr >= end) return true;
902
903 return false;
904 }
905
906
907 bool Thread::is_in_usable_stack(address adr) const {
908 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
909 size_t usable_stack_size = _stack_size - stack_guard_size;
910
911 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
912 }
913
914
915 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
916 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
917 // used for compilation in the future. If that change is made, the need for these methods
918 // should be revisited, and they should be removed if possible.
919
920 bool Thread::is_lock_owned(address adr) const {
921 return on_local_stack(adr);
922 }
923
924 bool Thread::set_as_starting_thread() {
925 // NOTE: this must be called inside the main thread.
926 return os::create_main_thread((JavaThread*)this);
927 }
928
929 static void initialize_class(Symbol* class_name, TRAPS) {
930 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
931 InstanceKlass::cast(klass)->initialize(CHECK);
932 }
933
934
935 // Creates the initial ThreadGroup
936 static Handle create_initial_thread_group(TRAPS) {
937 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
938 instanceKlassHandle klass (THREAD, k);
939
940 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
941 {
942 JavaValue result(T_VOID);
943 JavaCalls::call_special(&result,
944 system_instance,
945 klass,
946 vmSymbols::object_initializer_name(),
947 vmSymbols::void_method_signature(),
948 CHECK_NH);
949 }
950 Universe::set_system_thread_group(system_instance());
951
952 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
953 {
954 JavaValue result(T_VOID);
955 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
956 JavaCalls::call_special(&result,
957 main_instance,
958 klass,
959 vmSymbols::object_initializer_name(),
960 vmSymbols::threadgroup_string_void_signature(),
961 system_instance,
962 string,
963 CHECK_NH);
964 }
965 return main_instance;
966 }
967
968 // Creates the initial Thread
969 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
970 TRAPS) {
971 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
972 instanceKlassHandle klass (THREAD, k);
973 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
974
975 java_lang_Thread::set_thread(thread_oop(), thread);
976 java_lang_Thread::set_priority(thread_oop(), NormPriority);
977 thread->set_threadObj(thread_oop());
978
979 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
980
981 JavaValue result(T_VOID);
982 JavaCalls::call_special(&result, thread_oop,
983 klass,
984 vmSymbols::object_initializer_name(),
985 vmSymbols::threadgroup_string_void_signature(),
986 thread_group,
987 string,
988 CHECK_NULL);
989 return thread_oop();
990 }
991
992 static void call_initializeSystemClass(TRAPS) {
993 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
994 instanceKlassHandle klass (THREAD, k);
995
996 JavaValue result(T_VOID);
997 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
998 vmSymbols::void_method_signature(), CHECK);
999 }
1000
1001 char java_runtime_name[128] = "";
1002 char java_runtime_version[128] = "";
1003
1004 // extract the JRE name from sun.misc.Version.java_runtime_name
1005 static const char* get_java_runtime_name(TRAPS) {
1006 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1007 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1008 fieldDescriptor fd;
1009 bool found = k != NULL &&
1010 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1011 vmSymbols::string_signature(), &fd);
1012 if (found) {
1013 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1014 if (name_oop == NULL) {
1015 return NULL;
1016 }
1017 const char* name = java_lang_String::as_utf8_string(name_oop,
1018 java_runtime_name,
1019 sizeof(java_runtime_name));
1020 return name;
1021 } else {
1022 return NULL;
1023 }
1024 }
1025
1026 // extract the JRE version from sun.misc.Version.java_runtime_version
1027 static const char* get_java_runtime_version(TRAPS) {
1028 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1029 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1030 fieldDescriptor fd;
1031 bool found = k != NULL &&
1032 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1033 vmSymbols::string_signature(), &fd);
1034 if (found) {
1035 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1036 if (name_oop == NULL) {
1037 return NULL;
1038 }
1039 const char* name = java_lang_String::as_utf8_string(name_oop,
1040 java_runtime_version,
1041 sizeof(java_runtime_version));
1042 return name;
1043 } else {
1044 return NULL;
1045 }
1046 }
1047
1048 // General purpose hook into Java code, run once when the VM is initialized.
1049 // The Java library method itself may be changed independently from the VM.
1050 static void call_postVMInitHook(TRAPS) {
1051 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1052 instanceKlassHandle klass (THREAD, k);
1053 if (klass.not_null()) {
1054 JavaValue result(T_VOID);
1055 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1056 vmSymbols::void_method_signature(),
1057 CHECK);
1058 }
1059 }
1060
1061 static void reset_vm_info_property(TRAPS) {
1062 // the vm info string
1063 ResourceMark rm(THREAD);
1064 const char *vm_info = VM_Version::vm_info_string();
1065
1066 // java.lang.System class
1067 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1068 instanceKlassHandle klass (THREAD, k);
1069
1070 // setProperty arguments
1071 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1072 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1073
1074 // return value
1075 JavaValue r(T_OBJECT);
1076
1077 // public static String setProperty(String key, String value);
1078 JavaCalls::call_static(&r,
1079 klass,
1080 vmSymbols::setProperty_name(),
1081 vmSymbols::string_string_string_signature(),
1082 key_str,
1083 value_str,
1084 CHECK);
1085 }
1086
1087
1088 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1089 bool daemon, TRAPS) {
1090 assert(thread_group.not_null(), "thread group should be specified");
1091 assert(threadObj() == NULL, "should only create Java thread object once");
1092
1093 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1094 instanceKlassHandle klass (THREAD, k);
1095 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1096
1097 java_lang_Thread::set_thread(thread_oop(), this);
1098 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1099 set_threadObj(thread_oop());
1100
1101 JavaValue result(T_VOID);
1102 if (thread_name != NULL) {
1103 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1104 // Thread gets assigned specified name and null target
1105 JavaCalls::call_special(&result,
1106 thread_oop,
1107 klass,
1108 vmSymbols::object_initializer_name(),
1109 vmSymbols::threadgroup_string_void_signature(),
1110 thread_group, // Argument 1
1111 name, // Argument 2
1112 THREAD);
1113 } else {
1114 // Thread gets assigned name "Thread-nnn" and null target
1115 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1116 JavaCalls::call_special(&result,
1117 thread_oop,
1118 klass,
1119 vmSymbols::object_initializer_name(),
1120 vmSymbols::threadgroup_runnable_void_signature(),
1121 thread_group, // Argument 1
1122 Handle(), // Argument 2
1123 THREAD);
1124 }
1125
1126
1127 if (daemon) {
1128 java_lang_Thread::set_daemon(thread_oop());
1129 }
1130
1131 if (HAS_PENDING_EXCEPTION) {
1132 return;
1133 }
1134
1135 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1136 Handle threadObj(THREAD, this->threadObj());
1137
1138 JavaCalls::call_special(&result,
1139 thread_group,
1140 group,
1141 vmSymbols::add_method_name(),
1142 vmSymbols::thread_void_signature(),
1143 threadObj, // Arg 1
1144 THREAD);
1145 }
1146
1147 // NamedThread -- non-JavaThread subclasses with multiple
1148 // uniquely named instances should derive from this.
1149 NamedThread::NamedThread() : Thread() {
1150 _name = NULL;
1151 _processed_thread = NULL;
1152 }
1153
1154 NamedThread::~NamedThread() {
1155 if (_name != NULL) {
1156 FREE_C_HEAP_ARRAY(char, _name);
1157 _name = NULL;
1158 }
1159 }
1160
1161 void NamedThread::set_name(const char* format, ...) {
1162 guarantee(_name == NULL, "Only get to set name once.");
1163 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1164 guarantee(_name != NULL, "alloc failure");
1165 va_list ap;
1166 va_start(ap, format);
1167 jio_vsnprintf(_name, max_name_len, format, ap);
1168 va_end(ap);
1169 }
1170
1171 void NamedThread::initialize_named_thread() {
1172 set_native_thread_name(name());
1173 }
1174
1175 void NamedThread::print_on(outputStream* st) const {
1176 st->print("\"%s\" ", name());
1177 Thread::print_on(st);
1178 st->cr();
1179 }
1180
1181
1182 // ======= WatcherThread ========
1183
1184 // The watcher thread exists to simulate timer interrupts. It should
1185 // be replaced by an abstraction over whatever native support for
1186 // timer interrupts exists on the platform.
1187
1188 WatcherThread* WatcherThread::_watcher_thread = NULL;
1189 bool WatcherThread::_startable = false;
1190 volatile bool WatcherThread::_should_terminate = false;
1191
1192 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1193 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1194 if (os::create_thread(this, os::watcher_thread)) {
1195 _watcher_thread = this;
1196
1197 // Set the watcher thread to the highest OS priority which should not be
1198 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1199 // is created. The only normal thread using this priority is the reference
1200 // handler thread, which runs for very short intervals only.
1201 // If the VMThread's priority is not lower than the WatcherThread profiling
1202 // will be inaccurate.
1203 os::set_priority(this, MaxPriority);
1204 if (!DisableStartThread) {
1205 os::start_thread(this);
1206 }
1207 }
1208 }
1209
1210 int WatcherThread::sleep() const {
1211 // The WatcherThread does not participate in the safepoint protocol
1212 // for the PeriodicTask_lock because it is not a JavaThread.
1213 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1214
1215 if (_should_terminate) {
1216 // check for termination before we do any housekeeping or wait
1217 return 0; // we did not sleep.
1218 }
1219
1220 // remaining will be zero if there are no tasks,
1221 // causing the WatcherThread to sleep until a task is
1222 // enrolled
1223 int remaining = PeriodicTask::time_to_wait();
1224 int time_slept = 0;
1225
1226 // we expect this to timeout - we only ever get unparked when
1227 // we should terminate or when a new task has been enrolled
1228 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1229
1230 jlong time_before_loop = os::javaTimeNanos();
1231
1232 while (true) {
1233 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1234 remaining);
1235 jlong now = os::javaTimeNanos();
1236
1237 if (remaining == 0) {
1238 // if we didn't have any tasks we could have waited for a long time
1239 // consider the time_slept zero and reset time_before_loop
1240 time_slept = 0;
1241 time_before_loop = now;
1242 } else {
1243 // need to recalculate since we might have new tasks in _tasks
1244 time_slept = (int) ((now - time_before_loop) / 1000000);
1245 }
1246
1247 // Change to task list or spurious wakeup of some kind
1248 if (timedout || _should_terminate) {
1249 break;
1250 }
1251
1252 remaining = PeriodicTask::time_to_wait();
1253 if (remaining == 0) {
1254 // Last task was just disenrolled so loop around and wait until
1255 // another task gets enrolled
1256 continue;
1257 }
1258
1259 remaining -= time_slept;
1260 if (remaining <= 0) {
1261 break;
1262 }
1263 }
1264
1265 return time_slept;
1266 }
1267
1268 void WatcherThread::run() {
1269 assert(this == watcher_thread(), "just checking");
1270
1271 this->record_stack_base_and_size();
1272 this->initialize_thread_local_storage();
1273 this->set_native_thread_name(this->name());
1274 this->set_active_handles(JNIHandleBlock::allocate_block());
1275 while (true) {
1276 assert(watcher_thread() == Thread::current(), "thread consistency check");
1277 assert(watcher_thread() == this, "thread consistency check");
1278
1279 // Calculate how long it'll be until the next PeriodicTask work
1280 // should be done, and sleep that amount of time.
1281 int time_waited = sleep();
1282
1283 if (is_error_reported()) {
1284 // A fatal error has happened, the error handler(VMError::report_and_die)
1285 // should abort JVM after creating an error log file. However in some
1286 // rare cases, the error handler itself might deadlock. Here we try to
1287 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1288 //
1289 // This code is in WatcherThread because WatcherThread wakes up
1290 // periodically so the fatal error handler doesn't need to do anything;
1291 // also because the WatcherThread is less likely to crash than other
1292 // threads.
1293
1294 for (;;) {
1295 if (!ShowMessageBoxOnError
1296 && (OnError == NULL || OnError[0] == '\0')
1297 && Arguments::abort_hook() == NULL) {
1298 os::sleep(this, ErrorLogTimeout * 60 * 1000, false);
1299 fdStream err(defaultStream::output_fd());
1300 err.print_raw_cr("# [ timer expired, abort... ]");
1301 // skip atexit/vm_exit/vm_abort hooks
1302 os::die();
1303 }
1304
1305 // Wake up 5 seconds later, the fatal handler may reset OnError or
1306 // ShowMessageBoxOnError when it is ready to abort.
1307 os::sleep(this, 5 * 1000, false);
1308 }
1309 }
1310
1311 if (_should_terminate) {
1312 // check for termination before posting the next tick
1313 break;
1314 }
1315
1316 PeriodicTask::real_time_tick(time_waited);
1317 }
1318
1319 // Signal that it is terminated
1320 {
1321 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1322 _watcher_thread = NULL;
1323 Terminator_lock->notify();
1324 }
1325
1326 // Thread destructor usually does this..
1327 ThreadLocalStorage::set_thread(NULL);
1328 }
1329
1330 void WatcherThread::start() {
1331 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1332
1333 if (watcher_thread() == NULL && _startable) {
1334 _should_terminate = false;
1335 // Create the single instance of WatcherThread
1336 new WatcherThread();
1337 }
1338 }
1339
1340 void WatcherThread::make_startable() {
1341 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1342 _startable = true;
1343 }
1344
1345 void WatcherThread::stop() {
1346 {
1347 // Follow normal safepoint aware lock enter protocol since the
1348 // WatcherThread is stopped by another JavaThread.
1349 MutexLocker ml(PeriodicTask_lock);
1350 _should_terminate = true;
1351
1352 WatcherThread* watcher = watcher_thread();
1353 if (watcher != NULL) {
1354 // unpark the WatcherThread so it can see that it should terminate
1355 watcher->unpark();
1356 }
1357 }
1358
1359 MutexLocker mu(Terminator_lock);
1360
1361 while (watcher_thread() != NULL) {
1362 // This wait should make safepoint checks, wait without a timeout,
1363 // and wait as a suspend-equivalent condition.
1364 //
1365 // Note: If the FlatProfiler is running, then this thread is waiting
1366 // for the WatcherThread to terminate and the WatcherThread, via the
1367 // FlatProfiler task, is waiting for the external suspend request on
1368 // this thread to complete. wait_for_ext_suspend_completion() will
1369 // eventually timeout, but that takes time. Making this wait a
1370 // suspend-equivalent condition solves that timeout problem.
1371 //
1372 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1373 Mutex::_as_suspend_equivalent_flag);
1374 }
1375 }
1376
1377 void WatcherThread::unpark() {
1378 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1379 PeriodicTask_lock->notify();
1380 }
1381
1382 void WatcherThread::print_on(outputStream* st) const {
1383 st->print("\"%s\" ", name());
1384 Thread::print_on(st);
1385 st->cr();
1386 }
1387
1388 // ======= JavaThread ========
1389
1390 // A JavaThread is a normal Java thread
1391
1392 void JavaThread::initialize() {
1393 // Initialize fields
1394
1395 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1396 set_claimed_par_id(UINT_MAX);
1397
1398 set_saved_exception_pc(NULL);
1399 set_threadObj(NULL);
1400 _anchor.clear();
1401 set_entry_point(NULL);
1402 set_jni_functions(jni_functions());
1403 set_callee_target(NULL);
1404 set_vm_result(NULL);
1405 set_vm_result_2(NULL);
1406 set_vframe_array_head(NULL);
1407 set_vframe_array_last(NULL);
1408 set_deferred_locals(NULL);
1409 set_deopt_mark(NULL);
1410 set_deopt_nmethod(NULL);
1411 clear_must_deopt_id();
1412 set_monitor_chunks(NULL);
1413 set_next(NULL);
1414 set_thread_state(_thread_new);
1415 _terminated = _not_terminated;
1416 _privileged_stack_top = NULL;
1417 _array_for_gc = NULL;
1418 _suspend_equivalent = false;
1419 _in_deopt_handler = 0;
1420 _doing_unsafe_access = false;
1421 _stack_guard_state = stack_guard_unused;
1422 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1423 _exception_pc = 0;
1424 _exception_handler_pc = 0;
1425 _is_method_handle_return = 0;
1426 _jvmti_thread_state= NULL;
1427 _should_post_on_exceptions_flag = JNI_FALSE;
1428 _jvmti_get_loaded_classes_closure = NULL;
1429 _interp_only_mode = 0;
1430 _special_runtime_exit_condition = _no_async_condition;
1431 _pending_async_exception = NULL;
1432 _thread_stat = NULL;
1433 _thread_stat = new ThreadStatistics();
1434 _blocked_on_compilation = false;
1435 _jni_active_critical = 0;
1436 _pending_jni_exception_check_fn = NULL;
1437 _do_not_unlock_if_synchronized = false;
1438 _cached_monitor_info = NULL;
1439 _parker = Parker::Allocate(this);
1440
1441 #ifndef PRODUCT
1442 _jmp_ring_index = 0;
1443 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1444 record_jump(NULL, NULL, NULL, 0);
1445 }
1446 #endif // PRODUCT
1447
1448 set_thread_profiler(NULL);
1449 if (FlatProfiler::is_active()) {
1450 // This is where we would decide to either give each thread it's own profiler
1451 // or use one global one from FlatProfiler,
1452 // or up to some count of the number of profiled threads, etc.
1453 ThreadProfiler* pp = new ThreadProfiler();
1454 pp->engage();
1455 set_thread_profiler(pp);
1456 }
1457
1458 // Setup safepoint state info for this thread
1459 ThreadSafepointState::create(this);
1460
1461 debug_only(_java_call_counter = 0);
1462
1463 // JVMTI PopFrame support
1464 _popframe_condition = popframe_inactive;
1465 _popframe_preserved_args = NULL;
1466 _popframe_preserved_args_size = 0;
1467 _frames_to_pop_failed_realloc = 0;
1468
1469 pd_initialize();
1470 }
1471
1472 #if INCLUDE_ALL_GCS
1473 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1474 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1475 #endif // INCLUDE_ALL_GCS
1476
1477 JavaThread::JavaThread(bool is_attaching_via_jni) :
1478 Thread()
1479 #if INCLUDE_ALL_GCS
1480 , _satb_mark_queue(&_satb_mark_queue_set),
1481 _dirty_card_queue(&_dirty_card_queue_set)
1482 #endif // INCLUDE_ALL_GCS
1483 {
1484 initialize();
1485 if (is_attaching_via_jni) {
1486 _jni_attach_state = _attaching_via_jni;
1487 } else {
1488 _jni_attach_state = _not_attaching_via_jni;
1489 }
1490 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1491 }
1492
1493 bool JavaThread::reguard_stack(address cur_sp) {
1494 if (_stack_guard_state != stack_guard_yellow_disabled) {
1495 return true; // Stack already guarded or guard pages not needed.
1496 }
1497
1498 if (register_stack_overflow()) {
1499 // For those architectures which have separate register and
1500 // memory stacks, we must check the register stack to see if
1501 // it has overflowed.
1502 return false;
1503 }
1504
1505 // Java code never executes within the yellow zone: the latter is only
1506 // there to provoke an exception during stack banging. If java code
1507 // is executing there, either StackShadowPages should be larger, or
1508 // some exception code in c1, c2 or the interpreter isn't unwinding
1509 // when it should.
1510 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1511
1512 enable_stack_yellow_zone();
1513 return true;
1514 }
1515
1516 bool JavaThread::reguard_stack(void) {
1517 return reguard_stack(os::current_stack_pointer());
1518 }
1519
1520
1521 void JavaThread::block_if_vm_exited() {
1522 if (_terminated == _vm_exited) {
1523 // _vm_exited is set at safepoint, and Threads_lock is never released
1524 // we will block here forever
1525 Threads_lock->lock_without_safepoint_check();
1526 ShouldNotReachHere();
1527 }
1528 }
1529
1530
1531 // Remove this ifdef when C1 is ported to the compiler interface.
1532 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1533 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1534
1535 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1536 Thread()
1537 #if INCLUDE_ALL_GCS
1538 , _satb_mark_queue(&_satb_mark_queue_set),
1539 _dirty_card_queue(&_dirty_card_queue_set)
1540 #endif // INCLUDE_ALL_GCS
1541 {
1542 initialize();
1543 _jni_attach_state = _not_attaching_via_jni;
1544 set_entry_point(entry_point);
1545 // Create the native thread itself.
1546 // %note runtime_23
1547 os::ThreadType thr_type = os::java_thread;
1548 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1549 os::java_thread;
1550 os::create_thread(this, thr_type, stack_sz);
1551 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1552 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1553 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1554 // the exception consists of creating the exception object & initializing it, initialization
1555 // will leave the VM via a JavaCall and then all locks must be unlocked).
1556 //
1557 // The thread is still suspended when we reach here. Thread must be explicit started
1558 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1559 // by calling Threads:add. The reason why this is not done here, is because the thread
1560 // object must be fully initialized (take a look at JVM_Start)
1561 }
1562
1563 JavaThread::~JavaThread() {
1564
1565 // JSR166 -- return the parker to the free list
1566 Parker::Release(_parker);
1567 _parker = NULL;
1568
1569 // Free any remaining previous UnrollBlock
1570 vframeArray* old_array = vframe_array_last();
1571
1572 if (old_array != NULL) {
1573 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1574 old_array->set_unroll_block(NULL);
1575 delete old_info;
1576 delete old_array;
1577 }
1578
1579 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1580 if (deferred != NULL) {
1581 // This can only happen if thread is destroyed before deoptimization occurs.
1582 assert(deferred->length() != 0, "empty array!");
1583 do {
1584 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1585 deferred->remove_at(0);
1586 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1587 delete dlv;
1588 } while (deferred->length() != 0);
1589 delete deferred;
1590 }
1591
1592 // All Java related clean up happens in exit
1593 ThreadSafepointState::destroy(this);
1594 if (_thread_profiler != NULL) delete _thread_profiler;
1595 if (_thread_stat != NULL) delete _thread_stat;
1596 }
1597
1598
1599 // The first routine called by a new Java thread
1600 void JavaThread::run() {
1601 // initialize thread-local alloc buffer related fields
1602 this->initialize_tlab();
1603
1604 // used to test validity of stack trace backs
1605 this->record_base_of_stack_pointer();
1606
1607 // Record real stack base and size.
1608 this->record_stack_base_and_size();
1609
1610 // Initialize thread local storage; set before calling MutexLocker
1611 this->initialize_thread_local_storage();
1612
1613 this->create_stack_guard_pages();
1614
1615 this->cache_global_variables();
1616
1617 // Thread is now sufficient initialized to be handled by the safepoint code as being
1618 // in the VM. Change thread state from _thread_new to _thread_in_vm
1619 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1620
1621 assert(JavaThread::current() == this, "sanity check");
1622 assert(!Thread::current()->owns_locks(), "sanity check");
1623
1624 DTRACE_THREAD_PROBE(start, this);
1625
1626 // This operation might block. We call that after all safepoint checks for a new thread has
1627 // been completed.
1628 this->set_active_handles(JNIHandleBlock::allocate_block());
1629
1630 if (JvmtiExport::should_post_thread_life()) {
1631 JvmtiExport::post_thread_start(this);
1632 }
1633
1634 EventThreadStart event;
1635 if (event.should_commit()) {
1636 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1637 event.commit();
1638 }
1639
1640 // We call another function to do the rest so we are sure that the stack addresses used
1641 // from there will be lower than the stack base just computed
1642 thread_main_inner();
1643
1644 // Note, thread is no longer valid at this point!
1645 }
1646
1647
1648 void JavaThread::thread_main_inner() {
1649 assert(JavaThread::current() == this, "sanity check");
1650 assert(this->threadObj() != NULL, "just checking");
1651
1652 // Execute thread entry point unless this thread has a pending exception
1653 // or has been stopped before starting.
1654 // Note: Due to JVM_StopThread we can have pending exceptions already!
1655 if (!this->has_pending_exception() &&
1656 !java_lang_Thread::is_stillborn(this->threadObj())) {
1657 {
1658 ResourceMark rm(this);
1659 this->set_native_thread_name(this->get_thread_name());
1660 }
1661 HandleMark hm(this);
1662 this->entry_point()(this, this);
1663 }
1664
1665 DTRACE_THREAD_PROBE(stop, this);
1666
1667 this->exit(false);
1668 delete this;
1669 }
1670
1671
1672 static void ensure_join(JavaThread* thread) {
1673 // We do not need to grap the Threads_lock, since we are operating on ourself.
1674 Handle threadObj(thread, thread->threadObj());
1675 assert(threadObj.not_null(), "java thread object must exist");
1676 ObjectLocker lock(threadObj, thread);
1677 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1678 thread->clear_pending_exception();
1679 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1680 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1681 // Clear the native thread instance - this makes isAlive return false and allows the join()
1682 // to complete once we've done the notify_all below
1683 java_lang_Thread::set_thread(threadObj(), NULL);
1684 lock.notify_all(thread);
1685 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1686 thread->clear_pending_exception();
1687 }
1688
1689
1690 // For any new cleanup additions, please check to see if they need to be applied to
1691 // cleanup_failed_attach_current_thread as well.
1692 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1693 assert(this == JavaThread::current(), "thread consistency check");
1694
1695 HandleMark hm(this);
1696 Handle uncaught_exception(this, this->pending_exception());
1697 this->clear_pending_exception();
1698 Handle threadObj(this, this->threadObj());
1699 assert(threadObj.not_null(), "Java thread object should be created");
1700
1701 if (get_thread_profiler() != NULL) {
1702 get_thread_profiler()->disengage();
1703 ResourceMark rm;
1704 get_thread_profiler()->print(get_thread_name());
1705 }
1706
1707
1708 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1709 {
1710 EXCEPTION_MARK;
1711
1712 CLEAR_PENDING_EXCEPTION;
1713 }
1714 if (!destroy_vm) {
1715 if (uncaught_exception.not_null()) {
1716 EXCEPTION_MARK;
1717 // Call method Thread.dispatchUncaughtException().
1718 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1719 JavaValue result(T_VOID);
1720 JavaCalls::call_virtual(&result,
1721 threadObj, thread_klass,
1722 vmSymbols::dispatchUncaughtException_name(),
1723 vmSymbols::throwable_void_signature(),
1724 uncaught_exception,
1725 THREAD);
1726 if (HAS_PENDING_EXCEPTION) {
1727 ResourceMark rm(this);
1728 jio_fprintf(defaultStream::error_stream(),
1729 "\nException: %s thrown from the UncaughtExceptionHandler"
1730 " in thread \"%s\"\n",
1731 pending_exception()->klass()->external_name(),
1732 get_thread_name());
1733 CLEAR_PENDING_EXCEPTION;
1734 }
1735 }
1736
1737 // Called before the java thread exit since we want to read info
1738 // from java_lang_Thread object
1739 EventThreadEnd event;
1740 if (event.should_commit()) {
1741 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1742 event.commit();
1743 }
1744
1745 // Call after last event on thread
1746 EVENT_THREAD_EXIT(this);
1747
1748 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1749 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1750 // is deprecated anyhow.
1751 if (!is_Compiler_thread()) {
1752 int count = 3;
1753 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1754 EXCEPTION_MARK;
1755 JavaValue result(T_VOID);
1756 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1757 JavaCalls::call_virtual(&result,
1758 threadObj, thread_klass,
1759 vmSymbols::exit_method_name(),
1760 vmSymbols::void_method_signature(),
1761 THREAD);
1762 CLEAR_PENDING_EXCEPTION;
1763 }
1764 }
1765 // notify JVMTI
1766 if (JvmtiExport::should_post_thread_life()) {
1767 JvmtiExport::post_thread_end(this);
1768 }
1769
1770 // We have notified the agents that we are exiting, before we go on,
1771 // we must check for a pending external suspend request and honor it
1772 // in order to not surprise the thread that made the suspend request.
1773 while (true) {
1774 {
1775 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1776 if (!is_external_suspend()) {
1777 set_terminated(_thread_exiting);
1778 ThreadService::current_thread_exiting(this);
1779 break;
1780 }
1781 // Implied else:
1782 // Things get a little tricky here. We have a pending external
1783 // suspend request, but we are holding the SR_lock so we
1784 // can't just self-suspend. So we temporarily drop the lock
1785 // and then self-suspend.
1786 }
1787
1788 ThreadBlockInVM tbivm(this);
1789 java_suspend_self();
1790
1791 // We're done with this suspend request, but we have to loop around
1792 // and check again. Eventually we will get SR_lock without a pending
1793 // external suspend request and will be able to mark ourselves as
1794 // exiting.
1795 }
1796 // no more external suspends are allowed at this point
1797 } else {
1798 // before_exit() has already posted JVMTI THREAD_END events
1799 }
1800
1801 // Notify waiters on thread object. This has to be done after exit() is called
1802 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1803 // group should have the destroyed bit set before waiters are notified).
1804 ensure_join(this);
1805 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1806
1807 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1808 // held by this thread must be released. The spec does not distinguish
1809 // between JNI-acquired and regular Java monitors. We can only see
1810 // regular Java monitors here if monitor enter-exit matching is broken.
1811 //
1812 // Optionally release any monitors for regular JavaThread exits. This
1813 // is provided as a work around for any bugs in monitor enter-exit
1814 // matching. This can be expensive so it is not enabled by default.
1815 // ObjectMonitor::Knob_ExitRelease is a superset of the
1816 // JNIDetachReleasesMonitors option.
1817 //
1818 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1819 // ObjectSynchronizer::release_monitors_owned_by_thread().
1820 if ((exit_type == jni_detach && JNIDetachReleasesMonitors) ||
1821 ObjectMonitor::Knob_ExitRelease) {
1822 // Sanity check even though JNI DetachCurrentThread() would have
1823 // returned JNI_ERR if there was a Java frame. JavaThread exit
1824 // should be done executing Java code by the time we get here.
1825 assert(!this->has_last_Java_frame(),
1826 "should not have a Java frame when detaching or exiting");
1827 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1828 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1829 }
1830
1831 // These things needs to be done while we are still a Java Thread. Make sure that thread
1832 // is in a consistent state, in case GC happens
1833 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1834
1835 if (active_handles() != NULL) {
1836 JNIHandleBlock* block = active_handles();
1837 set_active_handles(NULL);
1838 JNIHandleBlock::release_block(block);
1839 }
1840
1841 if (free_handle_block() != NULL) {
1842 JNIHandleBlock* block = free_handle_block();
1843 set_free_handle_block(NULL);
1844 JNIHandleBlock::release_block(block);
1845 }
1846
1847 // These have to be removed while this is still a valid thread.
1848 remove_stack_guard_pages();
1849
1850 if (UseTLAB) {
1851 tlab().make_parsable(true); // retire TLAB
1852 }
1853
1854 if (JvmtiEnv::environments_might_exist()) {
1855 JvmtiExport::cleanup_thread(this);
1856 }
1857
1858 // We must flush any deferred card marks before removing a thread from
1859 // the list of active threads.
1860 Universe::heap()->flush_deferred_store_barrier(this);
1861 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1862
1863 #if INCLUDE_ALL_GCS
1864 // We must flush the G1-related buffers before removing a thread
1865 // from the list of active threads. We must do this after any deferred
1866 // card marks have been flushed (above) so that any entries that are
1867 // added to the thread's dirty card queue as a result are not lost.
1868 if (UseG1GC) {
1869 flush_barrier_queues();
1870 }
1871 #endif // INCLUDE_ALL_GCS
1872
1873 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1874 Threads::remove(this);
1875 }
1876
1877 #if INCLUDE_ALL_GCS
1878 // Flush G1-related queues.
1879 void JavaThread::flush_barrier_queues() {
1880 satb_mark_queue().flush();
1881 dirty_card_queue().flush();
1882 }
1883
1884 void JavaThread::initialize_queues() {
1885 assert(!SafepointSynchronize::is_at_safepoint(),
1886 "we should not be at a safepoint");
1887
1888 ObjPtrQueue& satb_queue = satb_mark_queue();
1889 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1890 // The SATB queue should have been constructed with its active
1891 // field set to false.
1892 assert(!satb_queue.is_active(), "SATB queue should not be active");
1893 assert(satb_queue.is_empty(), "SATB queue should be empty");
1894 // If we are creating the thread during a marking cycle, we should
1895 // set the active field of the SATB queue to true.
1896 if (satb_queue_set.is_active()) {
1897 satb_queue.set_active(true);
1898 }
1899
1900 DirtyCardQueue& dirty_queue = dirty_card_queue();
1901 // The dirty card queue should have been constructed with its
1902 // active field set to true.
1903 assert(dirty_queue.is_active(), "dirty card queue should be active");
1904 }
1905 #endif // INCLUDE_ALL_GCS
1906
1907 void JavaThread::cleanup_failed_attach_current_thread() {
1908 if (get_thread_profiler() != NULL) {
1909 get_thread_profiler()->disengage();
1910 ResourceMark rm;
1911 get_thread_profiler()->print(get_thread_name());
1912 }
1913
1914 if (active_handles() != NULL) {
1915 JNIHandleBlock* block = active_handles();
1916 set_active_handles(NULL);
1917 JNIHandleBlock::release_block(block);
1918 }
1919
1920 if (free_handle_block() != NULL) {
1921 JNIHandleBlock* block = free_handle_block();
1922 set_free_handle_block(NULL);
1923 JNIHandleBlock::release_block(block);
1924 }
1925
1926 // These have to be removed while this is still a valid thread.
1927 remove_stack_guard_pages();
1928
1929 if (UseTLAB) {
1930 tlab().make_parsable(true); // retire TLAB, if any
1931 }
1932
1933 #if INCLUDE_ALL_GCS
1934 if (UseG1GC) {
1935 flush_barrier_queues();
1936 }
1937 #endif // INCLUDE_ALL_GCS
1938
1939 Threads::remove(this);
1940 delete this;
1941 }
1942
1943
1944
1945
1946 JavaThread* JavaThread::active() {
1947 Thread* thread = ThreadLocalStorage::thread();
1948 assert(thread != NULL, "just checking");
1949 if (thread->is_Java_thread()) {
1950 return (JavaThread*) thread;
1951 } else {
1952 assert(thread->is_VM_thread(), "this must be a vm thread");
1953 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1954 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1955 assert(ret->is_Java_thread(), "must be a Java thread");
1956 return ret;
1957 }
1958 }
1959
1960 bool JavaThread::is_lock_owned(address adr) const {
1961 if (Thread::is_lock_owned(adr)) return true;
1962
1963 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1964 if (chunk->contains(adr)) return true;
1965 }
1966
1967 return false;
1968 }
1969
1970
1971 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1972 chunk->set_next(monitor_chunks());
1973 set_monitor_chunks(chunk);
1974 }
1975
1976 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1977 guarantee(monitor_chunks() != NULL, "must be non empty");
1978 if (monitor_chunks() == chunk) {
1979 set_monitor_chunks(chunk->next());
1980 } else {
1981 MonitorChunk* prev = monitor_chunks();
1982 while (prev->next() != chunk) prev = prev->next();
1983 prev->set_next(chunk->next());
1984 }
1985 }
1986
1987 // JVM support.
1988
1989 // Note: this function shouldn't block if it's called in
1990 // _thread_in_native_trans state (such as from
1991 // check_special_condition_for_native_trans()).
1992 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1993
1994 if (has_last_Java_frame() && has_async_condition()) {
1995 // If we are at a polling page safepoint (not a poll return)
1996 // then we must defer async exception because live registers
1997 // will be clobbered by the exception path. Poll return is
1998 // ok because the call we a returning from already collides
1999 // with exception handling registers and so there is no issue.
2000 // (The exception handling path kills call result registers but
2001 // this is ok since the exception kills the result anyway).
2002
2003 if (is_at_poll_safepoint()) {
2004 // if the code we are returning to has deoptimized we must defer
2005 // the exception otherwise live registers get clobbered on the
2006 // exception path before deoptimization is able to retrieve them.
2007 //
2008 RegisterMap map(this, false);
2009 frame caller_fr = last_frame().sender(&map);
2010 assert(caller_fr.is_compiled_frame(), "what?");
2011 if (caller_fr.is_deoptimized_frame()) {
2012 if (TraceExceptions) {
2013 ResourceMark rm;
2014 tty->print_cr("deferred async exception at compiled safepoint");
2015 }
2016 return;
2017 }
2018 }
2019 }
2020
2021 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2022 if (condition == _no_async_condition) {
2023 // Conditions have changed since has_special_runtime_exit_condition()
2024 // was called:
2025 // - if we were here only because of an external suspend request,
2026 // then that was taken care of above (or cancelled) so we are done
2027 // - if we were here because of another async request, then it has
2028 // been cleared between the has_special_runtime_exit_condition()
2029 // and now so again we are done
2030 return;
2031 }
2032
2033 // Check for pending async. exception
2034 if (_pending_async_exception != NULL) {
2035 // Only overwrite an already pending exception, if it is not a threadDeath.
2036 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2037
2038 // We cannot call Exceptions::_throw(...) here because we cannot block
2039 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2040
2041 if (TraceExceptions) {
2042 ResourceMark rm;
2043 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2044 if (has_last_Java_frame()) {
2045 frame f = last_frame();
2046 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2047 }
2048 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2049 }
2050 _pending_async_exception = NULL;
2051 clear_has_async_exception();
2052 }
2053 }
2054
2055 if (check_unsafe_error &&
2056 condition == _async_unsafe_access_error && !has_pending_exception()) {
2057 condition = _no_async_condition; // done
2058 switch (thread_state()) {
2059 case _thread_in_vm: {
2060 JavaThread* THREAD = this;
2061 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2062 }
2063 case _thread_in_native: {
2064 ThreadInVMfromNative tiv(this);
2065 JavaThread* THREAD = this;
2066 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2067 }
2068 case _thread_in_Java: {
2069 ThreadInVMfromJava tiv(this);
2070 JavaThread* THREAD = this;
2071 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2072 }
2073 default:
2074 ShouldNotReachHere();
2075 }
2076 }
2077
2078 assert(condition == _no_async_condition || has_pending_exception() ||
2079 (!check_unsafe_error && condition == _async_unsafe_access_error),
2080 "must have handled the async condition, if no exception");
2081 }
2082
2083 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2084 //
2085 // Check for pending external suspend. Internal suspend requests do
2086 // not use handle_special_runtime_exit_condition().
2087 // If JNIEnv proxies are allowed, don't self-suspend if the target
2088 // thread is not the current thread. In older versions of jdbx, jdbx
2089 // threads could call into the VM with another thread's JNIEnv so we
2090 // can be here operating on behalf of a suspended thread (4432884).
2091 bool do_self_suspend = is_external_suspend_with_lock();
2092 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2093 //
2094 // Because thread is external suspended the safepoint code will count
2095 // thread as at a safepoint. This can be odd because we can be here
2096 // as _thread_in_Java which would normally transition to _thread_blocked
2097 // at a safepoint. We would like to mark the thread as _thread_blocked
2098 // before calling java_suspend_self like all other callers of it but
2099 // we must then observe proper safepoint protocol. (We can't leave
2100 // _thread_blocked with a safepoint in progress). However we can be
2101 // here as _thread_in_native_trans so we can't use a normal transition
2102 // constructor/destructor pair because they assert on that type of
2103 // transition. We could do something like:
2104 //
2105 // JavaThreadState state = thread_state();
2106 // set_thread_state(_thread_in_vm);
2107 // {
2108 // ThreadBlockInVM tbivm(this);
2109 // java_suspend_self()
2110 // }
2111 // set_thread_state(_thread_in_vm_trans);
2112 // if (safepoint) block;
2113 // set_thread_state(state);
2114 //
2115 // but that is pretty messy. Instead we just go with the way the
2116 // code has worked before and note that this is the only path to
2117 // java_suspend_self that doesn't put the thread in _thread_blocked
2118 // mode.
2119
2120 frame_anchor()->make_walkable(this);
2121 java_suspend_self();
2122
2123 // We might be here for reasons in addition to the self-suspend request
2124 // so check for other async requests.
2125 }
2126
2127 if (check_asyncs) {
2128 check_and_handle_async_exceptions();
2129 }
2130 }
2131
2132 void JavaThread::send_thread_stop(oop java_throwable) {
2133 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2134 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2135 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2136
2137 // Do not throw asynchronous exceptions against the compiler thread
2138 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2139 if (is_Compiler_thread()) return;
2140
2141 {
2142 // Actually throw the Throwable against the target Thread - however
2143 // only if there is no thread death exception installed already.
2144 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2145 // If the topmost frame is a runtime stub, then we are calling into
2146 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2147 // must deoptimize the caller before continuing, as the compiled exception handler table
2148 // may not be valid
2149 if (has_last_Java_frame()) {
2150 frame f = last_frame();
2151 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2152 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2153 RegisterMap reg_map(this, UseBiasedLocking);
2154 frame compiled_frame = f.sender(®_map);
2155 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2156 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2157 }
2158 }
2159 }
2160
2161 // Set async. pending exception in thread.
2162 set_pending_async_exception(java_throwable);
2163
2164 if (TraceExceptions) {
2165 ResourceMark rm;
2166 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2167 }
2168 // for AbortVMOnException flag
2169 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2170 }
2171 }
2172
2173
2174 // Interrupt thread so it will wake up from a potential wait()
2175 Thread::interrupt(this);
2176 }
2177
2178 // External suspension mechanism.
2179 //
2180 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2181 // to any VM_locks and it is at a transition
2182 // Self-suspension will happen on the transition out of the vm.
2183 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2184 //
2185 // Guarantees on return:
2186 // + Target thread will not execute any new bytecode (that's why we need to
2187 // force a safepoint)
2188 // + Target thread will not enter any new monitors
2189 //
2190 void JavaThread::java_suspend() {
2191 { MutexLocker mu(Threads_lock);
2192 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2193 return;
2194 }
2195 }
2196
2197 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2198 if (!is_external_suspend()) {
2199 // a racing resume has cancelled us; bail out now
2200 return;
2201 }
2202
2203 // suspend is done
2204 uint32_t debug_bits = 0;
2205 // Warning: is_ext_suspend_completed() may temporarily drop the
2206 // SR_lock to allow the thread to reach a stable thread state if
2207 // it is currently in a transient thread state.
2208 if (is_ext_suspend_completed(false /* !called_by_wait */,
2209 SuspendRetryDelay, &debug_bits)) {
2210 return;
2211 }
2212 }
2213
2214 VM_ForceSafepoint vm_suspend;
2215 VMThread::execute(&vm_suspend);
2216 }
2217
2218 // Part II of external suspension.
2219 // A JavaThread self suspends when it detects a pending external suspend
2220 // request. This is usually on transitions. It is also done in places
2221 // where continuing to the next transition would surprise the caller,
2222 // e.g., monitor entry.
2223 //
2224 // Returns the number of times that the thread self-suspended.
2225 //
2226 // Note: DO NOT call java_suspend_self() when you just want to block current
2227 // thread. java_suspend_self() is the second stage of cooperative
2228 // suspension for external suspend requests and should only be used
2229 // to complete an external suspend request.
2230 //
2231 int JavaThread::java_suspend_self() {
2232 int ret = 0;
2233
2234 // we are in the process of exiting so don't suspend
2235 if (is_exiting()) {
2236 clear_external_suspend();
2237 return ret;
2238 }
2239
2240 assert(_anchor.walkable() ||
2241 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2242 "must have walkable stack");
2243
2244 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2245
2246 assert(!this->is_ext_suspended(),
2247 "a thread trying to self-suspend should not already be suspended");
2248
2249 if (this->is_suspend_equivalent()) {
2250 // If we are self-suspending as a result of the lifting of a
2251 // suspend equivalent condition, then the suspend_equivalent
2252 // flag is not cleared until we set the ext_suspended flag so
2253 // that wait_for_ext_suspend_completion() returns consistent
2254 // results.
2255 this->clear_suspend_equivalent();
2256 }
2257
2258 // A racing resume may have cancelled us before we grabbed SR_lock
2259 // above. Or another external suspend request could be waiting for us
2260 // by the time we return from SR_lock()->wait(). The thread
2261 // that requested the suspension may already be trying to walk our
2262 // stack and if we return now, we can change the stack out from under
2263 // it. This would be a "bad thing (TM)" and cause the stack walker
2264 // to crash. We stay self-suspended until there are no more pending
2265 // external suspend requests.
2266 while (is_external_suspend()) {
2267 ret++;
2268 this->set_ext_suspended();
2269
2270 // _ext_suspended flag is cleared by java_resume()
2271 while (is_ext_suspended()) {
2272 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2273 }
2274 }
2275
2276 return ret;
2277 }
2278
2279 #ifdef ASSERT
2280 // verify the JavaThread has not yet been published in the Threads::list, and
2281 // hence doesn't need protection from concurrent access at this stage
2282 void JavaThread::verify_not_published() {
2283 if (!Threads_lock->owned_by_self()) {
2284 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2285 assert(!Threads::includes(this),
2286 "java thread shouldn't have been published yet!");
2287 } else {
2288 assert(!Threads::includes(this),
2289 "java thread shouldn't have been published yet!");
2290 }
2291 }
2292 #endif
2293
2294 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2295 // progress or when _suspend_flags is non-zero.
2296 // Current thread needs to self-suspend if there is a suspend request and/or
2297 // block if a safepoint is in progress.
2298 // Async exception ISN'T checked.
2299 // Note only the ThreadInVMfromNative transition can call this function
2300 // directly and when thread state is _thread_in_native_trans
2301 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2302 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2303
2304 JavaThread *curJT = JavaThread::current();
2305 bool do_self_suspend = thread->is_external_suspend();
2306
2307 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2308
2309 // If JNIEnv proxies are allowed, don't self-suspend if the target
2310 // thread is not the current thread. In older versions of jdbx, jdbx
2311 // threads could call into the VM with another thread's JNIEnv so we
2312 // can be here operating on behalf of a suspended thread (4432884).
2313 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2314 JavaThreadState state = thread->thread_state();
2315
2316 // We mark this thread_blocked state as a suspend-equivalent so
2317 // that a caller to is_ext_suspend_completed() won't be confused.
2318 // The suspend-equivalent state is cleared by java_suspend_self().
2319 thread->set_suspend_equivalent();
2320
2321 // If the safepoint code sees the _thread_in_native_trans state, it will
2322 // wait until the thread changes to other thread state. There is no
2323 // guarantee on how soon we can obtain the SR_lock and complete the
2324 // self-suspend request. It would be a bad idea to let safepoint wait for
2325 // too long. Temporarily change the state to _thread_blocked to
2326 // let the VM thread know that this thread is ready for GC. The problem
2327 // of changing thread state is that safepoint could happen just after
2328 // java_suspend_self() returns after being resumed, and VM thread will
2329 // see the _thread_blocked state. We must check for safepoint
2330 // after restoring the state and make sure we won't leave while a safepoint
2331 // is in progress.
2332 thread->set_thread_state(_thread_blocked);
2333 thread->java_suspend_self();
2334 thread->set_thread_state(state);
2335 // Make sure new state is seen by VM thread
2336 if (os::is_MP()) {
2337 if (UseMembar) {
2338 // Force a fence between the write above and read below
2339 OrderAccess::fence();
2340 } else {
2341 // Must use this rather than serialization page in particular on Windows
2342 InterfaceSupport::serialize_memory(thread);
2343 }
2344 }
2345 }
2346
2347 if (SafepointSynchronize::do_call_back()) {
2348 // If we are safepointing, then block the caller which may not be
2349 // the same as the target thread (see above).
2350 SafepointSynchronize::block(curJT);
2351 }
2352
2353 if (thread->is_deopt_suspend()) {
2354 thread->clear_deopt_suspend();
2355 RegisterMap map(thread, false);
2356 frame f = thread->last_frame();
2357 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2358 f = f.sender(&map);
2359 }
2360 if (f.id() == thread->must_deopt_id()) {
2361 thread->clear_must_deopt_id();
2362 f.deoptimize(thread);
2363 } else {
2364 fatal("missed deoptimization!");
2365 }
2366 }
2367 }
2368
2369 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2370 // progress or when _suspend_flags is non-zero.
2371 // Current thread needs to self-suspend if there is a suspend request and/or
2372 // block if a safepoint is in progress.
2373 // Also check for pending async exception (not including unsafe access error).
2374 // Note only the native==>VM/Java barriers can call this function and when
2375 // thread state is _thread_in_native_trans.
2376 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2377 check_safepoint_and_suspend_for_native_trans(thread);
2378
2379 if (thread->has_async_exception()) {
2380 // We are in _thread_in_native_trans state, don't handle unsafe
2381 // access error since that may block.
2382 thread->check_and_handle_async_exceptions(false);
2383 }
2384 }
2385
2386 // This is a variant of the normal
2387 // check_special_condition_for_native_trans with slightly different
2388 // semantics for use by critical native wrappers. It does all the
2389 // normal checks but also performs the transition back into
2390 // thread_in_Java state. This is required so that critical natives
2391 // can potentially block and perform a GC if they are the last thread
2392 // exiting the GC_locker.
2393 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2394 check_special_condition_for_native_trans(thread);
2395
2396 // Finish the transition
2397 thread->set_thread_state(_thread_in_Java);
2398
2399 if (thread->do_critical_native_unlock()) {
2400 ThreadInVMfromJavaNoAsyncException tiv(thread);
2401 GC_locker::unlock_critical(thread);
2402 thread->clear_critical_native_unlock();
2403 }
2404 }
2405
2406 // We need to guarantee the Threads_lock here, since resumes are not
2407 // allowed during safepoint synchronization
2408 // Can only resume from an external suspension
2409 void JavaThread::java_resume() {
2410 assert_locked_or_safepoint(Threads_lock);
2411
2412 // Sanity check: thread is gone, has started exiting or the thread
2413 // was not externally suspended.
2414 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2415 return;
2416 }
2417
2418 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2419
2420 clear_external_suspend();
2421
2422 if (is_ext_suspended()) {
2423 clear_ext_suspended();
2424 SR_lock()->notify_all();
2425 }
2426 }
2427
2428 void JavaThread::create_stack_guard_pages() {
2429 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2430 address low_addr = stack_base() - stack_size();
2431 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2432
2433 int allocate = os::allocate_stack_guard_pages();
2434 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2435
2436 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2437 warning("Attempt to allocate stack guard pages failed.");
2438 return;
2439 }
2440
2441 if (os::guard_memory((char *) low_addr, len)) {
2442 _stack_guard_state = stack_guard_enabled;
2443 } else {
2444 warning("Attempt to protect stack guard pages failed.");
2445 if (os::uncommit_memory((char *) low_addr, len)) {
2446 warning("Attempt to deallocate stack guard pages failed.");
2447 }
2448 }
2449 }
2450
2451 void JavaThread::remove_stack_guard_pages() {
2452 assert(Thread::current() == this, "from different thread");
2453 if (_stack_guard_state == stack_guard_unused) return;
2454 address low_addr = stack_base() - stack_size();
2455 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2456
2457 if (os::allocate_stack_guard_pages()) {
2458 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2459 _stack_guard_state = stack_guard_unused;
2460 } else {
2461 warning("Attempt to deallocate stack guard pages failed.");
2462 }
2463 } else {
2464 if (_stack_guard_state == stack_guard_unused) return;
2465 if (os::unguard_memory((char *) low_addr, len)) {
2466 _stack_guard_state = stack_guard_unused;
2467 } else {
2468 warning("Attempt to unprotect stack guard pages failed.");
2469 }
2470 }
2471 }
2472
2473 void JavaThread::enable_stack_yellow_zone() {
2474 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2475 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2476
2477 // The base notation is from the stacks point of view, growing downward.
2478 // We need to adjust it to work correctly with guard_memory()
2479 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2480
2481 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2482 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2483
2484 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2485 _stack_guard_state = stack_guard_enabled;
2486 } else {
2487 warning("Attempt to guard stack yellow zone failed.");
2488 }
2489 enable_register_stack_guard();
2490 }
2491
2492 void JavaThread::disable_stack_yellow_zone() {
2493 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2494 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2495
2496 // Simply return if called for a thread that does not use guard pages.
2497 if (_stack_guard_state == stack_guard_unused) return;
2498
2499 // The base notation is from the stacks point of view, growing downward.
2500 // We need to adjust it to work correctly with guard_memory()
2501 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2502
2503 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2504 _stack_guard_state = stack_guard_yellow_disabled;
2505 } else {
2506 warning("Attempt to unguard stack yellow zone failed.");
2507 }
2508 disable_register_stack_guard();
2509 }
2510
2511 void JavaThread::enable_stack_red_zone() {
2512 // The base notation is from the stacks point of view, growing downward.
2513 // We need to adjust it to work correctly with guard_memory()
2514 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2515 address base = stack_red_zone_base() - stack_red_zone_size();
2516
2517 guarantee(base < stack_base(), "Error calculating stack red zone");
2518 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2519
2520 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2521 warning("Attempt to guard stack red zone failed.");
2522 }
2523 }
2524
2525 void JavaThread::disable_stack_red_zone() {
2526 // The base notation is from the stacks point of view, growing downward.
2527 // We need to adjust it to work correctly with guard_memory()
2528 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2529 address base = stack_red_zone_base() - stack_red_zone_size();
2530 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2531 warning("Attempt to unguard stack red zone failed.");
2532 }
2533 }
2534
2535 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2536 // ignore is there is no stack
2537 if (!has_last_Java_frame()) return;
2538 // traverse the stack frames. Starts from top frame.
2539 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2540 frame* fr = fst.current();
2541 f(fr, fst.register_map());
2542 }
2543 }
2544
2545
2546 #ifndef PRODUCT
2547 // Deoptimization
2548 // Function for testing deoptimization
2549 void JavaThread::deoptimize() {
2550 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2551 StackFrameStream fst(this, UseBiasedLocking);
2552 bool deopt = false; // Dump stack only if a deopt actually happens.
2553 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2554 // Iterate over all frames in the thread and deoptimize
2555 for (; !fst.is_done(); fst.next()) {
2556 if (fst.current()->can_be_deoptimized()) {
2557
2558 if (only_at) {
2559 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2560 // consists of comma or carriage return separated numbers so
2561 // search for the current bci in that string.
2562 address pc = fst.current()->pc();
2563 nmethod* nm = (nmethod*) fst.current()->cb();
2564 ScopeDesc* sd = nm->scope_desc_at(pc);
2565 char buffer[8];
2566 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2567 size_t len = strlen(buffer);
2568 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2569 while (found != NULL) {
2570 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2571 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2572 // Check that the bci found is bracketed by terminators.
2573 break;
2574 }
2575 found = strstr(found + 1, buffer);
2576 }
2577 if (!found) {
2578 continue;
2579 }
2580 }
2581
2582 if (DebugDeoptimization && !deopt) {
2583 deopt = true; // One-time only print before deopt
2584 tty->print_cr("[BEFORE Deoptimization]");
2585 trace_frames();
2586 trace_stack();
2587 }
2588 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2589 }
2590 }
2591
2592 if (DebugDeoptimization && deopt) {
2593 tty->print_cr("[AFTER Deoptimization]");
2594 trace_frames();
2595 }
2596 }
2597
2598
2599 // Make zombies
2600 void JavaThread::make_zombies() {
2601 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2602 if (fst.current()->can_be_deoptimized()) {
2603 // it is a Java nmethod
2604 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2605 nm->make_not_entrant();
2606 }
2607 }
2608 }
2609 #endif // PRODUCT
2610
2611
2612 void JavaThread::deoptimized_wrt_marked_nmethods() {
2613 if (!has_last_Java_frame()) return;
2614 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2615 StackFrameStream fst(this, UseBiasedLocking);
2616 for (; !fst.is_done(); fst.next()) {
2617 if (fst.current()->should_be_deoptimized()) {
2618 if (LogCompilation && xtty != NULL) {
2619 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2620 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2621 this->name(), nm != NULL ? nm->compile_id() : -1);
2622 }
2623
2624 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2625 }
2626 }
2627 }
2628
2629
2630 // If the caller is a NamedThread, then remember, in the current scope,
2631 // the given JavaThread in its _processed_thread field.
2632 class RememberProcessedThread: public StackObj {
2633 NamedThread* _cur_thr;
2634 public:
2635 RememberProcessedThread(JavaThread* jthr) {
2636 Thread* thread = Thread::current();
2637 if (thread->is_Named_thread()) {
2638 _cur_thr = (NamedThread *)thread;
2639 _cur_thr->set_processed_thread(jthr);
2640 } else {
2641 _cur_thr = NULL;
2642 }
2643 }
2644
2645 ~RememberProcessedThread() {
2646 if (_cur_thr) {
2647 _cur_thr->set_processed_thread(NULL);
2648 }
2649 }
2650 };
2651
2652 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2653 // Verify that the deferred card marks have been flushed.
2654 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2655
2656 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2657 // since there may be more than one thread using each ThreadProfiler.
2658
2659 // Traverse the GCHandles
2660 Thread::oops_do(f, cld_f, cf);
2661
2662 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2663 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2664
2665 if (has_last_Java_frame()) {
2666 // Record JavaThread to GC thread
2667 RememberProcessedThread rpt(this);
2668
2669 // Traverse the privileged stack
2670 if (_privileged_stack_top != NULL) {
2671 _privileged_stack_top->oops_do(f);
2672 }
2673
2674 // traverse the registered growable array
2675 if (_array_for_gc != NULL) {
2676 for (int index = 0; index < _array_for_gc->length(); index++) {
2677 f->do_oop(_array_for_gc->adr_at(index));
2678 }
2679 }
2680
2681 // Traverse the monitor chunks
2682 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2683 chunk->oops_do(f);
2684 }
2685
2686 // Traverse the execution stack
2687 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2688 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2689 }
2690 }
2691
2692 // callee_target is never live across a gc point so NULL it here should
2693 // it still contain a methdOop.
2694
2695 set_callee_target(NULL);
2696
2697 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2698 // If we have deferred set_locals there might be oops waiting to be
2699 // written
2700 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2701 if (list != NULL) {
2702 for (int i = 0; i < list->length(); i++) {
2703 list->at(i)->oops_do(f);
2704 }
2705 }
2706
2707 // Traverse instance variables at the end since the GC may be moving things
2708 // around using this function
2709 f->do_oop((oop*) &_threadObj);
2710 f->do_oop((oop*) &_vm_result);
2711 f->do_oop((oop*) &_exception_oop);
2712 f->do_oop((oop*) &_pending_async_exception);
2713
2714 if (jvmti_thread_state() != NULL) {
2715 jvmti_thread_state()->oops_do(f);
2716 }
2717 }
2718
2719 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2720 Thread::nmethods_do(cf); // (super method is a no-op)
2721
2722 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2723 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2724
2725 if (has_last_Java_frame()) {
2726 // Traverse the execution stack
2727 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2728 fst.current()->nmethods_do(cf);
2729 }
2730 }
2731 }
2732
2733 void JavaThread::metadata_do(void f(Metadata*)) {
2734 if (has_last_Java_frame()) {
2735 // Traverse the execution stack to call f() on the methods in the stack
2736 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2737 fst.current()->metadata_do(f);
2738 }
2739 } else if (is_Compiler_thread()) {
2740 // need to walk ciMetadata in current compile tasks to keep alive.
2741 CompilerThread* ct = (CompilerThread*)this;
2742 if (ct->env() != NULL) {
2743 ct->env()->metadata_do(f);
2744 }
2745 if (ct->task() != NULL) {
2746 ct->task()->metadata_do(f);
2747 }
2748 }
2749 }
2750
2751 // Printing
2752 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2753 switch (_thread_state) {
2754 case _thread_uninitialized: return "_thread_uninitialized";
2755 case _thread_new: return "_thread_new";
2756 case _thread_new_trans: return "_thread_new_trans";
2757 case _thread_in_native: return "_thread_in_native";
2758 case _thread_in_native_trans: return "_thread_in_native_trans";
2759 case _thread_in_vm: return "_thread_in_vm";
2760 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2761 case _thread_in_Java: return "_thread_in_Java";
2762 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2763 case _thread_blocked: return "_thread_blocked";
2764 case _thread_blocked_trans: return "_thread_blocked_trans";
2765 default: return "unknown thread state";
2766 }
2767 }
2768
2769 #ifndef PRODUCT
2770 void JavaThread::print_thread_state_on(outputStream *st) const {
2771 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2772 };
2773 void JavaThread::print_thread_state() const {
2774 print_thread_state_on(tty);
2775 }
2776 #endif // PRODUCT
2777
2778 // Called by Threads::print() for VM_PrintThreads operation
2779 void JavaThread::print_on(outputStream *st) const {
2780 st->print("\"%s\" ", get_thread_name());
2781 oop thread_oop = threadObj();
2782 if (thread_oop != NULL) {
2783 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2784 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2785 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2786 }
2787 Thread::print_on(st);
2788 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2789 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2790 if (thread_oop != NULL) {
2791 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2792 }
2793 #ifndef PRODUCT
2794 print_thread_state_on(st);
2795 _safepoint_state->print_on(st);
2796 #endif // PRODUCT
2797 }
2798
2799 // Called by fatal error handler. The difference between this and
2800 // JavaThread::print() is that we can't grab lock or allocate memory.
2801 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2802 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2803 oop thread_obj = threadObj();
2804 if (thread_obj != NULL) {
2805 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2806 }
2807 st->print(" [");
2808 st->print("%s", _get_thread_state_name(_thread_state));
2809 if (osthread()) {
2810 st->print(", id=%d", osthread()->thread_id());
2811 }
2812 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2813 _stack_base - _stack_size, _stack_base);
2814 st->print("]");
2815 return;
2816 }
2817
2818 // Verification
2819
2820 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2821
2822 void JavaThread::verify() {
2823 // Verify oops in the thread.
2824 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2825
2826 // Verify the stack frames.
2827 frames_do(frame_verify);
2828 }
2829
2830 // CR 6300358 (sub-CR 2137150)
2831 // Most callers of this method assume that it can't return NULL but a
2832 // thread may not have a name whilst it is in the process of attaching to
2833 // the VM - see CR 6412693, and there are places where a JavaThread can be
2834 // seen prior to having it's threadObj set (eg JNI attaching threads and
2835 // if vm exit occurs during initialization). These cases can all be accounted
2836 // for such that this method never returns NULL.
2837 const char* JavaThread::get_thread_name() const {
2838 #ifdef ASSERT
2839 // early safepoints can hit while current thread does not yet have TLS
2840 if (!SafepointSynchronize::is_at_safepoint()) {
2841 Thread *cur = Thread::current();
2842 if (!(cur->is_Java_thread() && cur == this)) {
2843 // Current JavaThreads are allowed to get their own name without
2844 // the Threads_lock.
2845 assert_locked_or_safepoint(Threads_lock);
2846 }
2847 }
2848 #endif // ASSERT
2849 return get_thread_name_string();
2850 }
2851
2852 // Returns a non-NULL representation of this thread's name, or a suitable
2853 // descriptive string if there is no set name
2854 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2855 const char* name_str;
2856 oop thread_obj = threadObj();
2857 if (thread_obj != NULL) {
2858 oop name = java_lang_Thread::name(thread_obj);
2859 if (name != NULL) {
2860 if (buf == NULL) {
2861 name_str = java_lang_String::as_utf8_string(name);
2862 } else {
2863 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2864 }
2865 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2866 name_str = "<no-name - thread is attaching>";
2867 } else {
2868 name_str = Thread::name();
2869 }
2870 } else {
2871 name_str = Thread::name();
2872 }
2873 assert(name_str != NULL, "unexpected NULL thread name");
2874 return name_str;
2875 }
2876
2877
2878 const char* JavaThread::get_threadgroup_name() const {
2879 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2880 oop thread_obj = threadObj();
2881 if (thread_obj != NULL) {
2882 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2883 if (thread_group != NULL) {
2884 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2885 // ThreadGroup.name can be null
2886 if (name != NULL) {
2887 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2888 return str;
2889 }
2890 }
2891 }
2892 return NULL;
2893 }
2894
2895 const char* JavaThread::get_parent_name() const {
2896 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2897 oop thread_obj = threadObj();
2898 if (thread_obj != NULL) {
2899 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2900 if (thread_group != NULL) {
2901 oop parent = java_lang_ThreadGroup::parent(thread_group);
2902 if (parent != NULL) {
2903 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2904 // ThreadGroup.name can be null
2905 if (name != NULL) {
2906 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2907 return str;
2908 }
2909 }
2910 }
2911 }
2912 return NULL;
2913 }
2914
2915 ThreadPriority JavaThread::java_priority() const {
2916 oop thr_oop = threadObj();
2917 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2918 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2919 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2920 return priority;
2921 }
2922
2923 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2924
2925 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2926 // Link Java Thread object <-> C++ Thread
2927
2928 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2929 // and put it into a new Handle. The Handle "thread_oop" can then
2930 // be used to pass the C++ thread object to other methods.
2931
2932 // Set the Java level thread object (jthread) field of the
2933 // new thread (a JavaThread *) to C++ thread object using the
2934 // "thread_oop" handle.
2935
2936 // Set the thread field (a JavaThread *) of the
2937 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2938
2939 Handle thread_oop(Thread::current(),
2940 JNIHandles::resolve_non_null(jni_thread));
2941 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2942 "must be initialized");
2943 set_threadObj(thread_oop());
2944 java_lang_Thread::set_thread(thread_oop(), this);
2945
2946 if (prio == NoPriority) {
2947 prio = java_lang_Thread::priority(thread_oop());
2948 assert(prio != NoPriority, "A valid priority should be present");
2949 }
2950
2951 // Push the Java priority down to the native thread; needs Threads_lock
2952 Thread::set_priority(this, prio);
2953
2954 prepare_ext();
2955
2956 // Add the new thread to the Threads list and set it in motion.
2957 // We must have threads lock in order to call Threads::add.
2958 // It is crucial that we do not block before the thread is
2959 // added to the Threads list for if a GC happens, then the java_thread oop
2960 // will not be visited by GC.
2961 Threads::add(this);
2962 }
2963
2964 oop JavaThread::current_park_blocker() {
2965 // Support for JSR-166 locks
2966 oop thread_oop = threadObj();
2967 if (thread_oop != NULL &&
2968 JDK_Version::current().supports_thread_park_blocker()) {
2969 return java_lang_Thread::park_blocker(thread_oop);
2970 }
2971 return NULL;
2972 }
2973
2974
2975 void JavaThread::print_stack_on(outputStream* st) {
2976 if (!has_last_Java_frame()) return;
2977 ResourceMark rm;
2978 HandleMark hm;
2979
2980 RegisterMap reg_map(this);
2981 vframe* start_vf = last_java_vframe(®_map);
2982 int count = 0;
2983 for (vframe* f = start_vf; f; f = f->sender()) {
2984 if (f->is_java_frame()) {
2985 javaVFrame* jvf = javaVFrame::cast(f);
2986 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2987
2988 // Print out lock information
2989 if (JavaMonitorsInStackTrace) {
2990 jvf->print_lock_info_on(st, count);
2991 }
2992 } else {
2993 // Ignore non-Java frames
2994 }
2995
2996 // Bail-out case for too deep stacks
2997 count++;
2998 if (MaxJavaStackTraceDepth == count) return;
2999 }
3000 }
3001
3002
3003 // JVMTI PopFrame support
3004 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3005 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3006 if (in_bytes(size_in_bytes) != 0) {
3007 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3008 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3009 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3010 }
3011 }
3012
3013 void* JavaThread::popframe_preserved_args() {
3014 return _popframe_preserved_args;
3015 }
3016
3017 ByteSize JavaThread::popframe_preserved_args_size() {
3018 return in_ByteSize(_popframe_preserved_args_size);
3019 }
3020
3021 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3022 int sz = in_bytes(popframe_preserved_args_size());
3023 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3024 return in_WordSize(sz / wordSize);
3025 }
3026
3027 void JavaThread::popframe_free_preserved_args() {
3028 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3029 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3030 _popframe_preserved_args = NULL;
3031 _popframe_preserved_args_size = 0;
3032 }
3033
3034 #ifndef PRODUCT
3035
3036 void JavaThread::trace_frames() {
3037 tty->print_cr("[Describe stack]");
3038 int frame_no = 1;
3039 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3040 tty->print(" %d. ", frame_no++);
3041 fst.current()->print_value_on(tty, this);
3042 tty->cr();
3043 }
3044 }
3045
3046 class PrintAndVerifyOopClosure: public OopClosure {
3047 protected:
3048 template <class T> inline void do_oop_work(T* p) {
3049 oop obj = oopDesc::load_decode_heap_oop(p);
3050 if (obj == NULL) return;
3051 tty->print(INTPTR_FORMAT ": ", p);
3052 if (obj->is_oop_or_null()) {
3053 if (obj->is_objArray()) {
3054 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3055 } else {
3056 obj->print();
3057 }
3058 } else {
3059 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3060 }
3061 tty->cr();
3062 }
3063 public:
3064 virtual void do_oop(oop* p) { do_oop_work(p); }
3065 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3066 };
3067
3068
3069 static void oops_print(frame* f, const RegisterMap *map) {
3070 PrintAndVerifyOopClosure print;
3071 f->print_value();
3072 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3073 }
3074
3075 // Print our all the locations that contain oops and whether they are
3076 // valid or not. This useful when trying to find the oldest frame
3077 // where an oop has gone bad since the frame walk is from youngest to
3078 // oldest.
3079 void JavaThread::trace_oops() {
3080 tty->print_cr("[Trace oops]");
3081 frames_do(oops_print);
3082 }
3083
3084
3085 #ifdef ASSERT
3086 // Print or validate the layout of stack frames
3087 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3088 ResourceMark rm;
3089 PRESERVE_EXCEPTION_MARK;
3090 FrameValues values;
3091 int frame_no = 0;
3092 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3093 fst.current()->describe(values, ++frame_no);
3094 if (depth == frame_no) break;
3095 }
3096 if (validate_only) {
3097 values.validate();
3098 } else {
3099 tty->print_cr("[Describe stack layout]");
3100 values.print(this);
3101 }
3102 }
3103 #endif
3104
3105 void JavaThread::trace_stack_from(vframe* start_vf) {
3106 ResourceMark rm;
3107 int vframe_no = 1;
3108 for (vframe* f = start_vf; f; f = f->sender()) {
3109 if (f->is_java_frame()) {
3110 javaVFrame::cast(f)->print_activation(vframe_no++);
3111 } else {
3112 f->print();
3113 }
3114 if (vframe_no > StackPrintLimit) {
3115 tty->print_cr("...<more frames>...");
3116 return;
3117 }
3118 }
3119 }
3120
3121
3122 void JavaThread::trace_stack() {
3123 if (!has_last_Java_frame()) return;
3124 ResourceMark rm;
3125 HandleMark hm;
3126 RegisterMap reg_map(this);
3127 trace_stack_from(last_java_vframe(®_map));
3128 }
3129
3130
3131 #endif // PRODUCT
3132
3133
3134 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3135 assert(reg_map != NULL, "a map must be given");
3136 frame f = last_frame();
3137 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3138 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3139 }
3140 return NULL;
3141 }
3142
3143
3144 Klass* JavaThread::security_get_caller_class(int depth) {
3145 vframeStream vfst(this);
3146 vfst.security_get_caller_frame(depth);
3147 if (!vfst.at_end()) {
3148 return vfst.method()->method_holder();
3149 }
3150 return NULL;
3151 }
3152
3153 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3154 assert(thread->is_Compiler_thread(), "must be compiler thread");
3155 CompileBroker::compiler_thread_loop();
3156 }
3157
3158 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3159 NMethodSweeper::sweeper_loop();
3160 }
3161
3162 // Create a CompilerThread
3163 CompilerThread::CompilerThread(CompileQueue* queue,
3164 CompilerCounters* counters)
3165 : JavaThread(&compiler_thread_entry) {
3166 _env = NULL;
3167 _log = NULL;
3168 _task = NULL;
3169 _queue = queue;
3170 _counters = counters;
3171 _buffer_blob = NULL;
3172 _compiler = NULL;
3173
3174 #ifndef PRODUCT
3175 _ideal_graph_printer = NULL;
3176 #endif
3177 }
3178
3179 // Create sweeper thread
3180 CodeCacheSweeperThread::CodeCacheSweeperThread()
3181 : JavaThread(&sweeper_thread_entry) {
3182 _scanned_nmethod = NULL;
3183 }
3184 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3185 JavaThread::oops_do(f, cld_f, cf);
3186 if (_scanned_nmethod != NULL && cf != NULL) {
3187 // Safepoints can occur when the sweeper is scanning an nmethod so
3188 // process it here to make sure it isn't unloaded in the middle of
3189 // a scan.
3190 cf->do_code_blob(_scanned_nmethod);
3191 }
3192 }
3193
3194
3195 // ======= Threads ========
3196
3197 // The Threads class links together all active threads, and provides
3198 // operations over all threads. It is protected by its own Mutex
3199 // lock, which is also used in other contexts to protect thread
3200 // operations from having the thread being operated on from exiting
3201 // and going away unexpectedly (e.g., safepoint synchronization)
3202
3203 JavaThread* Threads::_thread_list = NULL;
3204 int Threads::_number_of_threads = 0;
3205 int Threads::_number_of_non_daemon_threads = 0;
3206 int Threads::_return_code = 0;
3207 int Threads::_thread_claim_parity = 0;
3208 size_t JavaThread::_stack_size_at_create = 0;
3209 #ifdef ASSERT
3210 bool Threads::_vm_complete = false;
3211 #endif
3212
3213 // All JavaThreads
3214 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3215
3216 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3217 void Threads::threads_do(ThreadClosure* tc) {
3218 assert_locked_or_safepoint(Threads_lock);
3219 // ALL_JAVA_THREADS iterates through all JavaThreads
3220 ALL_JAVA_THREADS(p) {
3221 tc->do_thread(p);
3222 }
3223 // Someday we could have a table or list of all non-JavaThreads.
3224 // For now, just manually iterate through them.
3225 tc->do_thread(VMThread::vm_thread());
3226 Universe::heap()->gc_threads_do(tc);
3227 WatcherThread *wt = WatcherThread::watcher_thread();
3228 // Strictly speaking, the following NULL check isn't sufficient to make sure
3229 // the data for WatcherThread is still valid upon being examined. However,
3230 // considering that WatchThread terminates when the VM is on the way to
3231 // exit at safepoint, the chance of the above is extremely small. The right
3232 // way to prevent termination of WatcherThread would be to acquire
3233 // Terminator_lock, but we can't do that without violating the lock rank
3234 // checking in some cases.
3235 if (wt != NULL) {
3236 tc->do_thread(wt);
3237 }
3238
3239 // If CompilerThreads ever become non-JavaThreads, add them here
3240 }
3241
3242 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3243 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3244
3245 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3246 create_vm_init_libraries();
3247 }
3248
3249 initialize_class(vmSymbols::java_lang_String(), CHECK);
3250
3251 // Initialize java_lang.System (needed before creating the thread)
3252 initialize_class(vmSymbols::java_lang_System(), CHECK);
3253 // The VM creates & returns objects of this class. Make sure it's initialized.
3254 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3255 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3256 Handle thread_group = create_initial_thread_group(CHECK);
3257 Universe::set_main_thread_group(thread_group());
3258 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3259 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3260 main_thread->set_threadObj(thread_object);
3261 // Set thread status to running since main thread has
3262 // been started and running.
3263 java_lang_Thread::set_thread_status(thread_object,
3264 java_lang_Thread::RUNNABLE);
3265
3266 // The VM preresolves methods to these classes. Make sure that they get initialized
3267 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3268 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3269 call_initializeSystemClass(CHECK);
3270
3271 // get the Java runtime name after java.lang.System is initialized
3272 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3273 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3274
3275 // an instance of OutOfMemory exception has been allocated earlier
3276 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3277 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3278 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3279 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3280 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3281 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3282 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3283 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3284 }
3285
3286 void Threads::initialize_jsr292_core_classes(TRAPS) {
3287 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3288 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3289 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3290 }
3291
3292 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3293 extern void JDK_Version_init();
3294
3295 // Preinitialize version info.
3296 VM_Version::early_initialize();
3297
3298 // Check version
3299 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3300
3301 // Initialize the output stream module
3302 ostream_init();
3303
3304 // Process java launcher properties.
3305 Arguments::process_sun_java_launcher_properties(args);
3306
3307 // Initialize the os module before using TLS
3308 os::init();
3309
3310 // Record VM creation timing statistics
3311 TraceVmCreationTime create_vm_timer;
3312 create_vm_timer.start();
3313
3314 // Initialize system properties.
3315 Arguments::init_system_properties();
3316
3317 // So that JDK version can be used as a discriminator when parsing arguments
3318 JDK_Version_init();
3319
3320 // Update/Initialize System properties after JDK version number is known
3321 Arguments::init_version_specific_system_properties();
3322
3323 // Make sure to initialize log configuration *before* parsing arguments
3324 LogConfiguration::initialize(create_vm_timer.begin_time());
3325
3326 // Parse arguments
3327 jint parse_result = Arguments::parse(args);
3328 if (parse_result != JNI_OK) return parse_result;
3329
3330 os::init_before_ergo();
3331
3332 jint ergo_result = Arguments::apply_ergo();
3333 if (ergo_result != JNI_OK) return ergo_result;
3334
3335 // Final check of all ranges after ergonomics which may change values.
3336 if (!CommandLineFlagRangeList::check_ranges()) {
3337 return JNI_EINVAL;
3338 }
3339
3340 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3341 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3342 if (!constraint_result) {
3343 return JNI_EINVAL;
3344 }
3345
3346 if (PauseAtStartup) {
3347 os::pause();
3348 }
3349
3350 HOTSPOT_VM_INIT_BEGIN();
3351
3352 // Timing (must come after argument parsing)
3353 TraceTime timer("Create VM", TraceStartupTime);
3354
3355 // Initialize the os module after parsing the args
3356 jint os_init_2_result = os::init_2();
3357 if (os_init_2_result != JNI_OK) return os_init_2_result;
3358
3359 jint adjust_after_os_result = Arguments::adjust_after_os();
3360 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3361
3362 // initialize TLS
3363 ThreadLocalStorage::init();
3364
3365 // Initialize output stream logging
3366 ostream_init_log();
3367
3368 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3369 // Must be before create_vm_init_agents()
3370 if (Arguments::init_libraries_at_startup()) {
3371 convert_vm_init_libraries_to_agents();
3372 }
3373
3374 // Launch -agentlib/-agentpath and converted -Xrun agents
3375 if (Arguments::init_agents_at_startup()) {
3376 create_vm_init_agents();
3377 }
3378
3379 // Initialize Threads state
3380 _thread_list = NULL;
3381 _number_of_threads = 0;
3382 _number_of_non_daemon_threads = 0;
3383
3384 // Initialize global data structures and create system classes in heap
3385 vm_init_globals();
3386
3387 // Attach the main thread to this os thread
3388 JavaThread* main_thread = new JavaThread();
3389 main_thread->set_thread_state(_thread_in_vm);
3390 // must do this before set_active_handles and initialize_thread_local_storage
3391 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3392 // change the stack size recorded here to one based on the java thread
3393 // stacksize. This adjusted size is what is used to figure the placement
3394 // of the guard pages.
3395 main_thread->record_stack_base_and_size();
3396 main_thread->initialize_thread_local_storage();
3397
3398 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3399
3400 if (!main_thread->set_as_starting_thread()) {
3401 vm_shutdown_during_initialization(
3402 "Failed necessary internal allocation. Out of swap space");
3403 delete main_thread;
3404 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3405 return JNI_ENOMEM;
3406 }
3407
3408 // Enable guard page *after* os::create_main_thread(), otherwise it would
3409 // crash Linux VM, see notes in os_linux.cpp.
3410 main_thread->create_stack_guard_pages();
3411
3412 // Initialize Java-Level synchronization subsystem
3413 ObjectMonitor::Initialize();
3414
3415 // Initialize global modules
3416 jint status = init_globals();
3417 if (status != JNI_OK) {
3418 delete main_thread;
3419 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3420 return status;
3421 }
3422
3423 // Should be done after the heap is fully created
3424 main_thread->cache_global_variables();
3425
3426 HandleMark hm;
3427
3428 { MutexLocker mu(Threads_lock);
3429 Threads::add(main_thread);
3430 }
3431
3432 // Any JVMTI raw monitors entered in onload will transition into
3433 // real raw monitor. VM is setup enough here for raw monitor enter.
3434 JvmtiExport::transition_pending_onload_raw_monitors();
3435
3436 // Create the VMThread
3437 { TraceTime timer("Start VMThread", TraceStartupTime);
3438 VMThread::create();
3439 Thread* vmthread = VMThread::vm_thread();
3440
3441 if (!os::create_thread(vmthread, os::vm_thread)) {
3442 vm_exit_during_initialization("Cannot create VM thread. "
3443 "Out of system resources.");
3444 }
3445
3446 // Wait for the VM thread to become ready, and VMThread::run to initialize
3447 // Monitors can have spurious returns, must always check another state flag
3448 {
3449 MutexLocker ml(Notify_lock);
3450 os::start_thread(vmthread);
3451 while (vmthread->active_handles() == NULL) {
3452 Notify_lock->wait();
3453 }
3454 }
3455 }
3456
3457 assert(Universe::is_fully_initialized(), "not initialized");
3458 if (VerifyDuringStartup) {
3459 // Make sure we're starting with a clean slate.
3460 VM_Verify verify_op;
3461 VMThread::execute(&verify_op);
3462 }
3463
3464 Thread* THREAD = Thread::current();
3465
3466 // At this point, the Universe is initialized, but we have not executed
3467 // any byte code. Now is a good time (the only time) to dump out the
3468 // internal state of the JVM for sharing.
3469 if (DumpSharedSpaces) {
3470 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3471 ShouldNotReachHere();
3472 }
3473
3474 // Always call even when there are not JVMTI environments yet, since environments
3475 // may be attached late and JVMTI must track phases of VM execution
3476 JvmtiExport::enter_start_phase();
3477
3478 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3479 JvmtiExport::post_vm_start();
3480
3481 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3482
3483 // We need this for ClassDataSharing - the initial vm.info property is set
3484 // with the default value of CDS "sharing" which may be reset through
3485 // command line options.
3486 reset_vm_info_property(CHECK_JNI_ERR);
3487
3488 quicken_jni_functions();
3489
3490 // Must be run after init_ft which initializes ft_enabled
3491 if (TRACE_INITIALIZE() != JNI_OK) {
3492 vm_exit_during_initialization("Failed to initialize tracing backend");
3493 }
3494
3495 // Set flag that basic initialization has completed. Used by exceptions and various
3496 // debug stuff, that does not work until all basic classes have been initialized.
3497 set_init_completed();
3498
3499 LogConfiguration::post_initialize();
3500 Metaspace::post_initialize();
3501
3502 HOTSPOT_VM_INIT_END();
3503
3504 // record VM initialization completion time
3505 #if INCLUDE_MANAGEMENT
3506 Management::record_vm_init_completed();
3507 #endif // INCLUDE_MANAGEMENT
3508
3509 // Compute system loader. Note that this has to occur after set_init_completed, since
3510 // valid exceptions may be thrown in the process.
3511 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3512 // set_init_completed has just been called, causing exceptions not to be shortcut
3513 // anymore. We call vm_exit_during_initialization directly instead.
3514 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3515
3516 #if INCLUDE_ALL_GCS
3517 // Support for ConcurrentMarkSweep. This should be cleaned up
3518 // and better encapsulated. The ugly nested if test would go away
3519 // once things are properly refactored. XXX YSR
3520 if (UseConcMarkSweepGC || UseG1GC) {
3521 if (UseConcMarkSweepGC) {
3522 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3523 } else {
3524 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3525 }
3526 }
3527 #endif // INCLUDE_ALL_GCS
3528
3529 // Always call even when there are not JVMTI environments yet, since environments
3530 // may be attached late and JVMTI must track phases of VM execution
3531 JvmtiExport::enter_live_phase();
3532
3533 // Signal Dispatcher needs to be started before VMInit event is posted
3534 os::signal_init();
3535
3536 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3537 if (!DisableAttachMechanism) {
3538 AttachListener::vm_start();
3539 if (StartAttachListener || AttachListener::init_at_startup()) {
3540 AttachListener::init();
3541 }
3542 }
3543
3544 // Launch -Xrun agents
3545 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3546 // back-end can launch with -Xdebug -Xrunjdwp.
3547 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3548 create_vm_init_libraries();
3549 }
3550
3551 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3552 JvmtiExport::post_vm_initialized();
3553
3554 if (TRACE_START() != JNI_OK) {
3555 vm_exit_during_initialization("Failed to start tracing backend.");
3556 }
3557
3558 if (CleanChunkPoolAsync) {
3559 Chunk::start_chunk_pool_cleaner_task();
3560 }
3561
3562 // initialize compiler(s)
3563 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3564 CompileBroker::compilation_init();
3565 #endif
3566
3567 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3568 // It is done after compilers are initialized, because otherwise compilations of
3569 // signature polymorphic MH intrinsics can be missed
3570 // (see SystemDictionary::find_method_handle_intrinsic).
3571 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3572
3573 #if INCLUDE_MANAGEMENT
3574 Management::initialize(THREAD);
3575
3576 if (HAS_PENDING_EXCEPTION) {
3577 // management agent fails to start possibly due to
3578 // configuration problem and is responsible for printing
3579 // stack trace if appropriate. Simply exit VM.
3580 vm_exit(1);
3581 }
3582 #endif // INCLUDE_MANAGEMENT
3583
3584 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3585 if (MemProfiling) MemProfiler::engage();
3586 StatSampler::engage();
3587 if (CheckJNICalls) JniPeriodicChecker::engage();
3588
3589 BiasedLocking::init();
3590
3591 #if INCLUDE_RTM_OPT
3592 RTMLockingCounters::init();
3593 #endif
3594
3595 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3596 call_postVMInitHook(THREAD);
3597 // The Java side of PostVMInitHook.run must deal with all
3598 // exceptions and provide means of diagnosis.
3599 if (HAS_PENDING_EXCEPTION) {
3600 CLEAR_PENDING_EXCEPTION;
3601 }
3602 }
3603
3604 {
3605 MutexLocker ml(PeriodicTask_lock);
3606 // Make sure the WatcherThread can be started by WatcherThread::start()
3607 // or by dynamic enrollment.
3608 WatcherThread::make_startable();
3609 // Start up the WatcherThread if there are any periodic tasks
3610 // NOTE: All PeriodicTasks should be registered by now. If they
3611 // aren't, late joiners might appear to start slowly (we might
3612 // take a while to process their first tick).
3613 if (PeriodicTask::num_tasks() > 0) {
3614 WatcherThread::start();
3615 }
3616 }
3617
3618 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3619
3620 create_vm_timer.end();
3621 #ifdef ASSERT
3622 _vm_complete = true;
3623 #endif
3624 return JNI_OK;
3625 }
3626
3627 // type for the Agent_OnLoad and JVM_OnLoad entry points
3628 extern "C" {
3629 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3630 }
3631 // Find a command line agent library and return its entry point for
3632 // -agentlib: -agentpath: -Xrun
3633 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3634 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3635 const char *on_load_symbols[],
3636 size_t num_symbol_entries) {
3637 OnLoadEntry_t on_load_entry = NULL;
3638 void *library = NULL;
3639
3640 if (!agent->valid()) {
3641 char buffer[JVM_MAXPATHLEN];
3642 char ebuf[1024] = "";
3643 const char *name = agent->name();
3644 const char *msg = "Could not find agent library ";
3645
3646 // First check to see if agent is statically linked into executable
3647 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3648 library = agent->os_lib();
3649 } else if (agent->is_absolute_path()) {
3650 library = os::dll_load(name, ebuf, sizeof ebuf);
3651 if (library == NULL) {
3652 const char *sub_msg = " in absolute path, with error: ";
3653 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3654 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3655 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3656 // If we can't find the agent, exit.
3657 vm_exit_during_initialization(buf, NULL);
3658 FREE_C_HEAP_ARRAY(char, buf);
3659 }
3660 } else {
3661 // Try to load the agent from the standard dll directory
3662 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3663 name)) {
3664 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3665 }
3666 if (library == NULL) { // Try the local directory
3667 char ns[1] = {0};
3668 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3669 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3670 }
3671 if (library == NULL) {
3672 const char *sub_msg = " on the library path, with error: ";
3673 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3674 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3675 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3676 // If we can't find the agent, exit.
3677 vm_exit_during_initialization(buf, NULL);
3678 FREE_C_HEAP_ARRAY(char, buf);
3679 }
3680 }
3681 }
3682 agent->set_os_lib(library);
3683 agent->set_valid();
3684 }
3685
3686 // Find the OnLoad function.
3687 on_load_entry =
3688 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3689 false,
3690 on_load_symbols,
3691 num_symbol_entries));
3692 return on_load_entry;
3693 }
3694
3695 // Find the JVM_OnLoad entry point
3696 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3697 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3698 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3699 }
3700
3701 // Find the Agent_OnLoad entry point
3702 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3703 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3704 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3705 }
3706
3707 // For backwards compatibility with -Xrun
3708 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3709 // treated like -agentpath:
3710 // Must be called before agent libraries are created
3711 void Threads::convert_vm_init_libraries_to_agents() {
3712 AgentLibrary* agent;
3713 AgentLibrary* next;
3714
3715 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3716 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3717 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3718
3719 // If there is an JVM_OnLoad function it will get called later,
3720 // otherwise see if there is an Agent_OnLoad
3721 if (on_load_entry == NULL) {
3722 on_load_entry = lookup_agent_on_load(agent);
3723 if (on_load_entry != NULL) {
3724 // switch it to the agent list -- so that Agent_OnLoad will be called,
3725 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3726 Arguments::convert_library_to_agent(agent);
3727 } else {
3728 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3729 }
3730 }
3731 }
3732 }
3733
3734 // Create agents for -agentlib: -agentpath: and converted -Xrun
3735 // Invokes Agent_OnLoad
3736 // Called very early -- before JavaThreads exist
3737 void Threads::create_vm_init_agents() {
3738 extern struct JavaVM_ main_vm;
3739 AgentLibrary* agent;
3740
3741 JvmtiExport::enter_onload_phase();
3742
3743 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3744 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3745
3746 if (on_load_entry != NULL) {
3747 // Invoke the Agent_OnLoad function
3748 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3749 if (err != JNI_OK) {
3750 vm_exit_during_initialization("agent library failed to init", agent->name());
3751 }
3752 } else {
3753 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3754 }
3755 }
3756 JvmtiExport::enter_primordial_phase();
3757 }
3758
3759 extern "C" {
3760 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3761 }
3762
3763 void Threads::shutdown_vm_agents() {
3764 // Send any Agent_OnUnload notifications
3765 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3766 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3767 extern struct JavaVM_ main_vm;
3768 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3769
3770 // Find the Agent_OnUnload function.
3771 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3772 os::find_agent_function(agent,
3773 false,
3774 on_unload_symbols,
3775 num_symbol_entries));
3776
3777 // Invoke the Agent_OnUnload function
3778 if (unload_entry != NULL) {
3779 JavaThread* thread = JavaThread::current();
3780 ThreadToNativeFromVM ttn(thread);
3781 HandleMark hm(thread);
3782 (*unload_entry)(&main_vm);
3783 }
3784 }
3785 }
3786
3787 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3788 // Invokes JVM_OnLoad
3789 void Threads::create_vm_init_libraries() {
3790 extern struct JavaVM_ main_vm;
3791 AgentLibrary* agent;
3792
3793 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3794 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3795
3796 if (on_load_entry != NULL) {
3797 // Invoke the JVM_OnLoad function
3798 JavaThread* thread = JavaThread::current();
3799 ThreadToNativeFromVM ttn(thread);
3800 HandleMark hm(thread);
3801 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3802 if (err != JNI_OK) {
3803 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3804 }
3805 } else {
3806 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3807 }
3808 }
3809 }
3810
3811 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3812 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3813
3814 JavaThread* java_thread = NULL;
3815 // Sequential search for now. Need to do better optimization later.
3816 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3817 oop tobj = thread->threadObj();
3818 if (!thread->is_exiting() &&
3819 tobj != NULL &&
3820 java_tid == java_lang_Thread::thread_id(tobj)) {
3821 java_thread = thread;
3822 break;
3823 }
3824 }
3825 return java_thread;
3826 }
3827
3828
3829 // Last thread running calls java.lang.Shutdown.shutdown()
3830 void JavaThread::invoke_shutdown_hooks() {
3831 HandleMark hm(this);
3832
3833 // We could get here with a pending exception, if so clear it now.
3834 if (this->has_pending_exception()) {
3835 this->clear_pending_exception();
3836 }
3837
3838 EXCEPTION_MARK;
3839 Klass* k =
3840 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3841 THREAD);
3842 if (k != NULL) {
3843 // SystemDictionary::resolve_or_null will return null if there was
3844 // an exception. If we cannot load the Shutdown class, just don't
3845 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3846 // and finalizers (if runFinalizersOnExit is set) won't be run.
3847 // Note that if a shutdown hook was registered or runFinalizersOnExit
3848 // was called, the Shutdown class would have already been loaded
3849 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3850 instanceKlassHandle shutdown_klass (THREAD, k);
3851 JavaValue result(T_VOID);
3852 JavaCalls::call_static(&result,
3853 shutdown_klass,
3854 vmSymbols::shutdown_method_name(),
3855 vmSymbols::void_method_signature(),
3856 THREAD);
3857 }
3858 CLEAR_PENDING_EXCEPTION;
3859 }
3860
3861 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3862 // the program falls off the end of main(). Another VM exit path is through
3863 // vm_exit() when the program calls System.exit() to return a value or when
3864 // there is a serious error in VM. The two shutdown paths are not exactly
3865 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3866 // and VM_Exit op at VM level.
3867 //
3868 // Shutdown sequence:
3869 // + Shutdown native memory tracking if it is on
3870 // + Wait until we are the last non-daemon thread to execute
3871 // <-- every thing is still working at this moment -->
3872 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3873 // shutdown hooks, run finalizers if finalization-on-exit
3874 // + Call before_exit(), prepare for VM exit
3875 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3876 // currently the only user of this mechanism is File.deleteOnExit())
3877 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3878 // post thread end and vm death events to JVMTI,
3879 // stop signal thread
3880 // + Call JavaThread::exit(), it will:
3881 // > release JNI handle blocks, remove stack guard pages
3882 // > remove this thread from Threads list
3883 // <-- no more Java code from this thread after this point -->
3884 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3885 // the compiler threads at safepoint
3886 // <-- do not use anything that could get blocked by Safepoint -->
3887 // + Disable tracing at JNI/JVM barriers
3888 // + Set _vm_exited flag for threads that are still running native code
3889 // + Delete this thread
3890 // + Call exit_globals()
3891 // > deletes tty
3892 // > deletes PerfMemory resources
3893 // + Return to caller
3894
3895 bool Threads::destroy_vm() {
3896 JavaThread* thread = JavaThread::current();
3897
3898 #ifdef ASSERT
3899 _vm_complete = false;
3900 #endif
3901 // Wait until we are the last non-daemon thread to execute
3902 { MutexLocker nu(Threads_lock);
3903 while (Threads::number_of_non_daemon_threads() > 1)
3904 // This wait should make safepoint checks, wait without a timeout,
3905 // and wait as a suspend-equivalent condition.
3906 //
3907 // Note: If the FlatProfiler is running and this thread is waiting
3908 // for another non-daemon thread to finish, then the FlatProfiler
3909 // is waiting for the external suspend request on this thread to
3910 // complete. wait_for_ext_suspend_completion() will eventually
3911 // timeout, but that takes time. Making this wait a suspend-
3912 // equivalent condition solves that timeout problem.
3913 //
3914 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3915 Mutex::_as_suspend_equivalent_flag);
3916 }
3917
3918 // Hang forever on exit if we are reporting an error.
3919 if (ShowMessageBoxOnError && is_error_reported()) {
3920 os::infinite_sleep();
3921 }
3922 os::wait_for_keypress_at_exit();
3923
3924 // run Java level shutdown hooks
3925 thread->invoke_shutdown_hooks();
3926
3927 before_exit(thread);
3928
3929 thread->exit(true);
3930
3931 // Stop VM thread.
3932 {
3933 // 4945125 The vm thread comes to a safepoint during exit.
3934 // GC vm_operations can get caught at the safepoint, and the
3935 // heap is unparseable if they are caught. Grab the Heap_lock
3936 // to prevent this. The GC vm_operations will not be able to
3937 // queue until after the vm thread is dead. After this point,
3938 // we'll never emerge out of the safepoint before the VM exits.
3939
3940 MutexLocker ml(Heap_lock);
3941
3942 VMThread::wait_for_vm_thread_exit();
3943 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3944 VMThread::destroy();
3945 }
3946
3947 // clean up ideal graph printers
3948 #if defined(COMPILER2) && !defined(PRODUCT)
3949 IdealGraphPrinter::clean_up();
3950 #endif
3951
3952 // Now, all Java threads are gone except daemon threads. Daemon threads
3953 // running Java code or in VM are stopped by the Safepoint. However,
3954 // daemon threads executing native code are still running. But they
3955 // will be stopped at native=>Java/VM barriers. Note that we can't
3956 // simply kill or suspend them, as it is inherently deadlock-prone.
3957
3958 #ifndef PRODUCT
3959 // disable function tracing at JNI/JVM barriers
3960 TraceJNICalls = false;
3961 TraceJVMCalls = false;
3962 TraceRuntimeCalls = false;
3963 #endif
3964
3965 VM_Exit::set_vm_exited();
3966
3967 notify_vm_shutdown();
3968
3969 delete thread;
3970
3971 // exit_globals() will delete tty
3972 exit_globals();
3973
3974 LogConfiguration::finalize();
3975
3976 return true;
3977 }
3978
3979
3980 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3981 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3982 return is_supported_jni_version(version);
3983 }
3984
3985
3986 jboolean Threads::is_supported_jni_version(jint version) {
3987 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3988 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3989 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3990 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3991 return JNI_FALSE;
3992 }
3993
3994
3995 void Threads::add(JavaThread* p, bool force_daemon) {
3996 // The threads lock must be owned at this point
3997 assert_locked_or_safepoint(Threads_lock);
3998
3999 // See the comment for this method in thread.hpp for its purpose and
4000 // why it is called here.
4001 p->initialize_queues();
4002 p->set_next(_thread_list);
4003 _thread_list = p;
4004 _number_of_threads++;
4005 oop threadObj = p->threadObj();
4006 bool daemon = true;
4007 // Bootstrapping problem: threadObj can be null for initial
4008 // JavaThread (or for threads attached via JNI)
4009 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4010 _number_of_non_daemon_threads++;
4011 daemon = false;
4012 }
4013
4014 ThreadService::add_thread(p, daemon);
4015
4016 // Possible GC point.
4017 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4018 }
4019
4020 void Threads::remove(JavaThread* p) {
4021 // Extra scope needed for Thread_lock, so we can check
4022 // that we do not remove thread without safepoint code notice
4023 { MutexLocker ml(Threads_lock);
4024
4025 assert(includes(p), "p must be present");
4026
4027 JavaThread* current = _thread_list;
4028 JavaThread* prev = NULL;
4029
4030 while (current != p) {
4031 prev = current;
4032 current = current->next();
4033 }
4034
4035 if (prev) {
4036 prev->set_next(current->next());
4037 } else {
4038 _thread_list = p->next();
4039 }
4040 _number_of_threads--;
4041 oop threadObj = p->threadObj();
4042 bool daemon = true;
4043 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4044 _number_of_non_daemon_threads--;
4045 daemon = false;
4046
4047 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4048 // on destroy_vm will wake up.
4049 if (number_of_non_daemon_threads() == 1) {
4050 Threads_lock->notify_all();
4051 }
4052 }
4053 ThreadService::remove_thread(p, daemon);
4054
4055 // Make sure that safepoint code disregard this thread. This is needed since
4056 // the thread might mess around with locks after this point. This can cause it
4057 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4058 // of this thread since it is removed from the queue.
4059 p->set_terminated_value();
4060 } // unlock Threads_lock
4061
4062 // Since Events::log uses a lock, we grab it outside the Threads_lock
4063 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4064 }
4065
4066 // Threads_lock must be held when this is called (or must be called during a safepoint)
4067 bool Threads::includes(JavaThread* p) {
4068 assert(Threads_lock->is_locked(), "sanity check");
4069 ALL_JAVA_THREADS(q) {
4070 if (q == p) {
4071 return true;
4072 }
4073 }
4074 return false;
4075 }
4076
4077 // Operations on the Threads list for GC. These are not explicitly locked,
4078 // but the garbage collector must provide a safe context for them to run.
4079 // In particular, these things should never be called when the Threads_lock
4080 // is held by some other thread. (Note: the Safepoint abstraction also
4081 // uses the Threads_lock to guarantee this property. It also makes sure that
4082 // all threads gets blocked when exiting or starting).
4083
4084 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4085 ALL_JAVA_THREADS(p) {
4086 p->oops_do(f, cld_f, cf);
4087 }
4088 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4089 }
4090
4091 void Threads::change_thread_claim_parity() {
4092 // Set the new claim parity.
4093 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4094 "Not in range.");
4095 _thread_claim_parity++;
4096 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4097 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4098 "Not in range.");
4099 }
4100
4101 #ifdef ASSERT
4102 void Threads::assert_all_threads_claimed() {
4103 ALL_JAVA_THREADS(p) {
4104 const int thread_parity = p->oops_do_parity();
4105 assert((thread_parity == _thread_claim_parity),
4106 err_msg("Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity));
4107 }
4108 }
4109 #endif // ASSERT
4110
4111 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4112 int cp = Threads::thread_claim_parity();
4113 ALL_JAVA_THREADS(p) {
4114 if (p->claim_oops_do(is_par, cp)) {
4115 p->oops_do(f, cld_f, cf);
4116 }
4117 }
4118 VMThread* vmt = VMThread::vm_thread();
4119 if (vmt->claim_oops_do(is_par, cp)) {
4120 vmt->oops_do(f, cld_f, cf);
4121 }
4122 }
4123
4124 #if INCLUDE_ALL_GCS
4125 // Used by ParallelScavenge
4126 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4127 ALL_JAVA_THREADS(p) {
4128 q->enqueue(new ThreadRootsTask(p));
4129 }
4130 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4131 }
4132
4133 // Used by Parallel Old
4134 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4135 ALL_JAVA_THREADS(p) {
4136 q->enqueue(new ThreadRootsMarkingTask(p));
4137 }
4138 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4139 }
4140 #endif // INCLUDE_ALL_GCS
4141
4142 void Threads::nmethods_do(CodeBlobClosure* cf) {
4143 ALL_JAVA_THREADS(p) {
4144 p->nmethods_do(cf);
4145 }
4146 VMThread::vm_thread()->nmethods_do(cf);
4147 }
4148
4149 void Threads::metadata_do(void f(Metadata*)) {
4150 ALL_JAVA_THREADS(p) {
4151 p->metadata_do(f);
4152 }
4153 }
4154
4155 class ThreadHandlesClosure : public ThreadClosure {
4156 void (*_f)(Metadata*);
4157 public:
4158 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4159 virtual void do_thread(Thread* thread) {
4160 thread->metadata_handles_do(_f);
4161 }
4162 };
4163
4164 void Threads::metadata_handles_do(void f(Metadata*)) {
4165 // Only walk the Handles in Thread.
4166 ThreadHandlesClosure handles_closure(f);
4167 threads_do(&handles_closure);
4168 }
4169
4170 void Threads::deoptimized_wrt_marked_nmethods() {
4171 ALL_JAVA_THREADS(p) {
4172 p->deoptimized_wrt_marked_nmethods();
4173 }
4174 }
4175
4176
4177 // Get count Java threads that are waiting to enter the specified monitor.
4178 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4179 address monitor,
4180 bool doLock) {
4181 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4182 "must grab Threads_lock or be at safepoint");
4183 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4184
4185 int i = 0;
4186 {
4187 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4188 ALL_JAVA_THREADS(p) {
4189 if (p->is_Compiler_thread()) continue;
4190
4191 address pending = (address)p->current_pending_monitor();
4192 if (pending == monitor) { // found a match
4193 if (i < count) result->append(p); // save the first count matches
4194 i++;
4195 }
4196 }
4197 }
4198 return result;
4199 }
4200
4201
4202 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4203 bool doLock) {
4204 assert(doLock ||
4205 Threads_lock->owned_by_self() ||
4206 SafepointSynchronize::is_at_safepoint(),
4207 "must grab Threads_lock or be at safepoint");
4208
4209 // NULL owner means not locked so we can skip the search
4210 if (owner == NULL) return NULL;
4211
4212 {
4213 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4214 ALL_JAVA_THREADS(p) {
4215 // first, see if owner is the address of a Java thread
4216 if (owner == (address)p) return p;
4217 }
4218 }
4219 // Cannot assert on lack of success here since this function may be
4220 // used by code that is trying to report useful problem information
4221 // like deadlock detection.
4222 if (UseHeavyMonitors) return NULL;
4223
4224 // If we didn't find a matching Java thread and we didn't force use of
4225 // heavyweight monitors, then the owner is the stack address of the
4226 // Lock Word in the owning Java thread's stack.
4227 //
4228 JavaThread* the_owner = NULL;
4229 {
4230 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4231 ALL_JAVA_THREADS(q) {
4232 if (q->is_lock_owned(owner)) {
4233 the_owner = q;
4234 break;
4235 }
4236 }
4237 }
4238 // cannot assert on lack of success here; see above comment
4239 return the_owner;
4240 }
4241
4242 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4243 void Threads::print_on(outputStream* st, bool print_stacks,
4244 bool internal_format, bool print_concurrent_locks) {
4245 char buf[32];
4246 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4247
4248 st->print_cr("Full thread dump %s (%s %s):",
4249 Abstract_VM_Version::vm_name(),
4250 Abstract_VM_Version::vm_release(),
4251 Abstract_VM_Version::vm_info_string());
4252 st->cr();
4253
4254 #if INCLUDE_SERVICES
4255 // Dump concurrent locks
4256 ConcurrentLocksDump concurrent_locks;
4257 if (print_concurrent_locks) {
4258 concurrent_locks.dump_at_safepoint();
4259 }
4260 #endif // INCLUDE_SERVICES
4261
4262 ALL_JAVA_THREADS(p) {
4263 ResourceMark rm;
4264 p->print_on(st);
4265 if (print_stacks) {
4266 if (internal_format) {
4267 p->trace_stack();
4268 } else {
4269 p->print_stack_on(st);
4270 }
4271 }
4272 st->cr();
4273 #if INCLUDE_SERVICES
4274 if (print_concurrent_locks) {
4275 concurrent_locks.print_locks_on(p, st);
4276 }
4277 #endif // INCLUDE_SERVICES
4278 }
4279
4280 VMThread::vm_thread()->print_on(st);
4281 st->cr();
4282 Universe::heap()->print_gc_threads_on(st);
4283 WatcherThread* wt = WatcherThread::watcher_thread();
4284 if (wt != NULL) {
4285 wt->print_on(st);
4286 st->cr();
4287 }
4288 CompileBroker::print_compiler_threads_on(st);
4289 st->flush();
4290 }
4291
4292 // Threads::print_on_error() is called by fatal error handler. It's possible
4293 // that VM is not at safepoint and/or current thread is inside signal handler.
4294 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4295 // memory (even in resource area), it might deadlock the error handler.
4296 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4297 int buflen) {
4298 bool found_current = false;
4299 st->print_cr("Java Threads: ( => current thread )");
4300 ALL_JAVA_THREADS(thread) {
4301 bool is_current = (current == thread);
4302 found_current = found_current || is_current;
4303
4304 st->print("%s", is_current ? "=>" : " ");
4305
4306 st->print(PTR_FORMAT, thread);
4307 st->print(" ");
4308 thread->print_on_error(st, buf, buflen);
4309 st->cr();
4310 }
4311 st->cr();
4312
4313 st->print_cr("Other Threads:");
4314 if (VMThread::vm_thread()) {
4315 bool is_current = (current == VMThread::vm_thread());
4316 found_current = found_current || is_current;
4317 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4318
4319 st->print(PTR_FORMAT, VMThread::vm_thread());
4320 st->print(" ");
4321 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4322 st->cr();
4323 }
4324 WatcherThread* wt = WatcherThread::watcher_thread();
4325 if (wt != NULL) {
4326 bool is_current = (current == wt);
4327 found_current = found_current || is_current;
4328 st->print("%s", is_current ? "=>" : " ");
4329
4330 st->print(PTR_FORMAT, wt);
4331 st->print(" ");
4332 wt->print_on_error(st, buf, buflen);
4333 st->cr();
4334 }
4335 if (!found_current) {
4336 st->cr();
4337 st->print("=>" PTR_FORMAT " (exited) ", current);
4338 current->print_on_error(st, buf, buflen);
4339 st->cr();
4340 }
4341 }
4342
4343 // Internal SpinLock and Mutex
4344 // Based on ParkEvent
4345
4346 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4347 //
4348 // We employ SpinLocks _only for low-contention, fixed-length
4349 // short-duration critical sections where we're concerned
4350 // about native mutex_t or HotSpot Mutex:: latency.
4351 // The mux construct provides a spin-then-block mutual exclusion
4352 // mechanism.
4353 //
4354 // Testing has shown that contention on the ListLock guarding gFreeList
4355 // is common. If we implement ListLock as a simple SpinLock it's common
4356 // for the JVM to devolve to yielding with little progress. This is true
4357 // despite the fact that the critical sections protected by ListLock are
4358 // extremely short.
4359 //
4360 // TODO-FIXME: ListLock should be of type SpinLock.
4361 // We should make this a 1st-class type, integrated into the lock
4362 // hierarchy as leaf-locks. Critically, the SpinLock structure
4363 // should have sufficient padding to avoid false-sharing and excessive
4364 // cache-coherency traffic.
4365
4366
4367 typedef volatile int SpinLockT;
4368
4369 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4370 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4371 return; // normal fast-path return
4372 }
4373
4374 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4375 TEVENT(SpinAcquire - ctx);
4376 int ctr = 0;
4377 int Yields = 0;
4378 for (;;) {
4379 while (*adr != 0) {
4380 ++ctr;
4381 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4382 if (Yields > 5) {
4383 os::naked_short_sleep(1);
4384 } else {
4385 os::naked_yield();
4386 ++Yields;
4387 }
4388 } else {
4389 SpinPause();
4390 }
4391 }
4392 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4393 }
4394 }
4395
4396 void Thread::SpinRelease(volatile int * adr) {
4397 assert(*adr != 0, "invariant");
4398 OrderAccess::fence(); // guarantee at least release consistency.
4399 // Roach-motel semantics.
4400 // It's safe if subsequent LDs and STs float "up" into the critical section,
4401 // but prior LDs and STs within the critical section can't be allowed
4402 // to reorder or float past the ST that releases the lock.
4403 // Loads and stores in the critical section - which appear in program
4404 // order before the store that releases the lock - must also appear
4405 // before the store that releases the lock in memory visibility order.
4406 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4407 // the ST of 0 into the lock-word which releases the lock, so fence
4408 // more than covers this on all platforms.
4409 *adr = 0;
4410 }
4411
4412 // muxAcquire and muxRelease:
4413 //
4414 // * muxAcquire and muxRelease support a single-word lock-word construct.
4415 // The LSB of the word is set IFF the lock is held.
4416 // The remainder of the word points to the head of a singly-linked list
4417 // of threads blocked on the lock.
4418 //
4419 // * The current implementation of muxAcquire-muxRelease uses its own
4420 // dedicated Thread._MuxEvent instance. If we're interested in
4421 // minimizing the peak number of extant ParkEvent instances then
4422 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4423 // as certain invariants were satisfied. Specifically, care would need
4424 // to be taken with regards to consuming unpark() "permits".
4425 // A safe rule of thumb is that a thread would never call muxAcquire()
4426 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4427 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4428 // consume an unpark() permit intended for monitorenter, for instance.
4429 // One way around this would be to widen the restricted-range semaphore
4430 // implemented in park(). Another alternative would be to provide
4431 // multiple instances of the PlatformEvent() for each thread. One
4432 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4433 //
4434 // * Usage:
4435 // -- Only as leaf locks
4436 // -- for short-term locking only as muxAcquire does not perform
4437 // thread state transitions.
4438 //
4439 // Alternatives:
4440 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4441 // but with parking or spin-then-park instead of pure spinning.
4442 // * Use Taura-Oyama-Yonenzawa locks.
4443 // * It's possible to construct a 1-0 lock if we encode the lockword as
4444 // (List,LockByte). Acquire will CAS the full lockword while Release
4445 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4446 // acquiring threads use timers (ParkTimed) to detect and recover from
4447 // the stranding window. Thread/Node structures must be aligned on 256-byte
4448 // boundaries by using placement-new.
4449 // * Augment MCS with advisory back-link fields maintained with CAS().
4450 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4451 // The validity of the backlinks must be ratified before we trust the value.
4452 // If the backlinks are invalid the exiting thread must back-track through the
4453 // the forward links, which are always trustworthy.
4454 // * Add a successor indication. The LockWord is currently encoded as
4455 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4456 // to provide the usual futile-wakeup optimization.
4457 // See RTStt for details.
4458 // * Consider schedctl.sc_nopreempt to cover the critical section.
4459 //
4460
4461
4462 typedef volatile intptr_t MutexT; // Mux Lock-word
4463 enum MuxBits { LOCKBIT = 1 };
4464
4465 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4466 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4467 if (w == 0) return;
4468 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4469 return;
4470 }
4471
4472 TEVENT(muxAcquire - Contention);
4473 ParkEvent * const Self = Thread::current()->_MuxEvent;
4474 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4475 for (;;) {
4476 int its = (os::is_MP() ? 100 : 0) + 1;
4477
4478 // Optional spin phase: spin-then-park strategy
4479 while (--its >= 0) {
4480 w = *Lock;
4481 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4482 return;
4483 }
4484 }
4485
4486 Self->reset();
4487 Self->OnList = intptr_t(Lock);
4488 // The following fence() isn't _strictly necessary as the subsequent
4489 // CAS() both serializes execution and ratifies the fetched *Lock value.
4490 OrderAccess::fence();
4491 for (;;) {
4492 w = *Lock;
4493 if ((w & LOCKBIT) == 0) {
4494 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4495 Self->OnList = 0; // hygiene - allows stronger asserts
4496 return;
4497 }
4498 continue; // Interference -- *Lock changed -- Just retry
4499 }
4500 assert(w & LOCKBIT, "invariant");
4501 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4502 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4503 }
4504
4505 while (Self->OnList != 0) {
4506 Self->park();
4507 }
4508 }
4509 }
4510
4511 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4512 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4513 if (w == 0) return;
4514 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4515 return;
4516 }
4517
4518 TEVENT(muxAcquire - Contention);
4519 ParkEvent * ReleaseAfter = NULL;
4520 if (ev == NULL) {
4521 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4522 }
4523 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4524 for (;;) {
4525 guarantee(ev->OnList == 0, "invariant");
4526 int its = (os::is_MP() ? 100 : 0) + 1;
4527
4528 // Optional spin phase: spin-then-park strategy
4529 while (--its >= 0) {
4530 w = *Lock;
4531 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4532 if (ReleaseAfter != NULL) {
4533 ParkEvent::Release(ReleaseAfter);
4534 }
4535 return;
4536 }
4537 }
4538
4539 ev->reset();
4540 ev->OnList = intptr_t(Lock);
4541 // The following fence() isn't _strictly necessary as the subsequent
4542 // CAS() both serializes execution and ratifies the fetched *Lock value.
4543 OrderAccess::fence();
4544 for (;;) {
4545 w = *Lock;
4546 if ((w & LOCKBIT) == 0) {
4547 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4548 ev->OnList = 0;
4549 // We call ::Release while holding the outer lock, thus
4550 // artificially lengthening the critical section.
4551 // Consider deferring the ::Release() until the subsequent unlock(),
4552 // after we've dropped the outer lock.
4553 if (ReleaseAfter != NULL) {
4554 ParkEvent::Release(ReleaseAfter);
4555 }
4556 return;
4557 }
4558 continue; // Interference -- *Lock changed -- Just retry
4559 }
4560 assert(w & LOCKBIT, "invariant");
4561 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4562 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4563 }
4564
4565 while (ev->OnList != 0) {
4566 ev->park();
4567 }
4568 }
4569 }
4570
4571 // Release() must extract a successor from the list and then wake that thread.
4572 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4573 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4574 // Release() would :
4575 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4576 // (B) Extract a successor from the private list "in-hand"
4577 // (C) attempt to CAS() the residual back into *Lock over null.
4578 // If there were any newly arrived threads and the CAS() would fail.
4579 // In that case Release() would detach the RATs, re-merge the list in-hand
4580 // with the RATs and repeat as needed. Alternately, Release() might
4581 // detach and extract a successor, but then pass the residual list to the wakee.
4582 // The wakee would be responsible for reattaching and remerging before it
4583 // competed for the lock.
4584 //
4585 // Both "pop" and DMR are immune from ABA corruption -- there can be
4586 // multiple concurrent pushers, but only one popper or detacher.
4587 // This implementation pops from the head of the list. This is unfair,
4588 // but tends to provide excellent throughput as hot threads remain hot.
4589 // (We wake recently run threads first).
4590 //
4591 // All paths through muxRelease() will execute a CAS.
4592 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4593 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4594 // executed within the critical section are complete and globally visible before the
4595 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4596 void Thread::muxRelease(volatile intptr_t * Lock) {
4597 for (;;) {
4598 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4599 assert(w & LOCKBIT, "invariant");
4600 if (w == LOCKBIT) return;
4601 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4602 assert(List != NULL, "invariant");
4603 assert(List->OnList == intptr_t(Lock), "invariant");
4604 ParkEvent * const nxt = List->ListNext;
4605 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4606
4607 // The following CAS() releases the lock and pops the head element.
4608 // The CAS() also ratifies the previously fetched lock-word value.
4609 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4610 continue;
4611 }
4612 List->OnList = 0;
4613 OrderAccess::fence();
4614 List->unpark();
4615 return;
4616 }
4617 }
4618
4619
4620 void Threads::verify() {
4621 ALL_JAVA_THREADS(p) {
4622 p->verify();
4623 }
4624 VMThread* thread = VMThread::vm_thread();
4625 if (thread != NULL) thread->verify();
4626 }