1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/codeCacheExtensions.hpp"
32 #include "code/scopeDesc.hpp"
33 #include "compiler/compileBroker.hpp"
34 #include "gc/shared/gcLocker.inline.hpp"
35 #include "gc/shared/workgroup.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "interpreter/linkResolver.hpp"
38 #include "interpreter/oopMapCache.hpp"
39 #include "jvmtifiles/jvmtiEnv.hpp"
40 #include "memory/metaspaceShared.hpp"
41 #include "memory/oopFactory.hpp"
42 #include "memory/universe.inline.hpp"
43 #include "oops/instanceKlass.hpp"
44 #include "oops/objArrayOop.hpp"
45 #include "oops/oop.inline.hpp"
46 #include "oops/symbol.hpp"
47 #include "oops/verifyOopClosure.hpp"
48 #include "prims/jvm_misc.hpp"
49 #include "prims/jvmtiExport.hpp"
50 #include "prims/jvmtiThreadState.hpp"
51 #include "prims/privilegedStack.hpp"
52 #include "runtime/arguments.hpp"
53 #include "runtime/atomic.inline.hpp"
54 #include "runtime/biasedLocking.hpp"
55 #include "runtime/commandLineFlagConstraintList.hpp"
56 #include "runtime/commandLineFlagRangeList.hpp"
57 #include "runtime/deoptimization.hpp"
58 #include "runtime/fprofiler.hpp"
59 #include "runtime/frame.inline.hpp"
60 #include "runtime/globals.hpp"
61 #include "runtime/init.hpp"
62 #include "runtime/interfaceSupport.hpp"
63 #include "runtime/java.hpp"
64 #include "runtime/javaCalls.hpp"
65 #include "runtime/jniPeriodicChecker.hpp"
66 #include "runtime/memprofiler.hpp"
67 #include "runtime/mutexLocker.hpp"
68 #include "runtime/objectMonitor.hpp"
69 #include "runtime/orderAccess.inline.hpp"
70 #include "runtime/osThread.hpp"
71 #include "runtime/safepoint.hpp"
72 #include "runtime/sharedRuntime.hpp"
73 #include "runtime/statSampler.hpp"
74 #include "runtime/stubRoutines.hpp"
75 #include "runtime/sweeper.hpp"
76 #include "runtime/task.hpp"
77 #include "runtime/thread.inline.hpp"
78 #include "runtime/threadCritical.hpp"
79 #include "runtime/threadLocalStorage.hpp"
80 #include "runtime/vframe.hpp"
81 #include "runtime/vframeArray.hpp"
82 #include "runtime/vframe_hp.hpp"
83 #include "runtime/vmThread.hpp"
84 #include "runtime/vm_operations.hpp"
85 #include "runtime/vm_version.hpp"
86 #include "services/attachListener.hpp"
87 #include "services/management.hpp"
88 #include "services/memTracker.hpp"
89 #include "services/threadService.hpp"
90 #include "trace/traceMacros.hpp"
91 #include "trace/tracing.hpp"
92 #include "utilities/defaultStream.hpp"
93 #include "utilities/dtrace.hpp"
94 #include "utilities/events.hpp"
95 #include "utilities/macros.hpp"
96 #include "utilities/preserveException.hpp"
97 #if INCLUDE_ALL_GCS
98 #include "gc/shenandoah/shenandoahConcurrentThread.hpp"
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 _evacuating = false;
267
268 #ifdef CHECK_UNHANDLED_OOPS
269 if (CheckUnhandledOops) {
270 _unhandled_oops = new UnhandledOops(this);
271 }
272 #endif // CHECK_UNHANDLED_OOPS
273 #ifdef ASSERT
274 if (UseBiasedLocking) {
275 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
276 assert(this == _real_malloc_address ||
277 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
278 "bug in forced alignment of thread objects");
279 }
280 #endif // ASSERT
281 }
282
283 // Non-inlined version to be used where thread.inline.hpp shouldn't be included.
284 Thread* Thread::current_noinline() {
285 return Thread::current();
286 }
287
288 void Thread::initialize_thread_local_storage() {
289 // Note: Make sure this method only calls
290 // non-blocking operations. Otherwise, it might not work
291 // with the thread-startup/safepoint interaction.
292
293 // During Java thread startup, safepoint code should allow this
294 // method to complete because it may need to allocate memory to
295 // store information for the new thread.
296
297 // initialize structure dependent on thread local storage
298 ThreadLocalStorage::set_thread(this);
299 }
300
301 void Thread::record_stack_base_and_size() {
302 set_stack_base(os::current_stack_base());
303 set_stack_size(os::current_stack_size());
304 if (is_Java_thread()) {
305 ((JavaThread*) this)->set_stack_overflow_limit();
306 }
307 // CR 7190089: on Solaris, primordial thread's stack is adjusted
308 // in initialize_thread(). Without the adjustment, stack size is
309 // incorrect if stack is set to unlimited (ulimit -s unlimited).
310 // So far, only Solaris has real implementation of initialize_thread().
311 //
312 // set up any platform-specific state.
313 os::initialize_thread(this);
314
315 #if INCLUDE_NMT
316 // record thread's native stack, stack grows downward
317 address stack_low_addr = stack_base() - stack_size();
318 MemTracker::record_thread_stack(stack_low_addr, stack_size());
319 #endif // INCLUDE_NMT
320 }
321
322
323 Thread::~Thread() {
324 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
325 ObjectSynchronizer::omFlush(this);
326
327 EVENT_THREAD_DESTRUCT(this);
328
329 // stack_base can be NULL if the thread is never started or exited before
330 // record_stack_base_and_size called. Although, we would like to ensure
331 // that all started threads do call record_stack_base_and_size(), there is
332 // not proper way to enforce that.
333 #if INCLUDE_NMT
334 if (_stack_base != NULL) {
335 address low_stack_addr = stack_base() - stack_size();
336 MemTracker::release_thread_stack(low_stack_addr, stack_size());
337 #ifdef ASSERT
338 set_stack_base(NULL);
339 #endif
340 }
341 #endif // INCLUDE_NMT
342
343 // deallocate data structures
344 delete resource_area();
345 // since the handle marks are using the handle area, we have to deallocated the root
346 // handle mark before deallocating the thread's handle area,
347 assert(last_handle_mark() != NULL, "check we have an element");
348 delete last_handle_mark();
349 assert(last_handle_mark() == NULL, "check we have reached the end");
350
351 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
352 // We NULL out the fields for good hygiene.
353 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
354 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
355 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
356 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
357
358 delete handle_area();
359 delete metadata_handles();
360
361 // osthread() can be NULL, if creation of thread failed.
362 if (osthread() != NULL) os::free_thread(osthread());
363
364 delete _SR_lock;
365
366 // clear thread local storage if the Thread is deleting itself
367 if (this == Thread::current()) {
368 ThreadLocalStorage::set_thread(NULL);
369 } else {
370 // In the case where we're not the current thread, invalidate all the
371 // caches in case some code tries to get the current thread or the
372 // thread that was destroyed, and gets stale information.
373 ThreadLocalStorage::invalidate_all();
374 }
375 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
376 }
377
378 // NOTE: dummy function for assertion purpose.
379 void Thread::run() {
380 ShouldNotReachHere();
381 }
382
383 #ifdef ASSERT
384 // Private method to check for dangling thread pointer
385 void check_for_dangling_thread_pointer(Thread *thread) {
386 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
387 "possibility of dangling Thread pointer");
388 }
389 #endif
390
391 ThreadPriority Thread::get_priority(const Thread* const thread) {
392 ThreadPriority priority;
393 // Can return an error!
394 (void)os::get_priority(thread, priority);
395 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
396 return priority;
397 }
398
399 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
400 debug_only(check_for_dangling_thread_pointer(thread);)
401 // Can return an error!
402 (void)os::set_priority(thread, priority);
403 }
404
405
406 void Thread::start(Thread* thread) {
407 // Start is different from resume in that its safety is guaranteed by context or
408 // being called from a Java method synchronized on the Thread object.
409 if (!DisableStartThread) {
410 if (thread->is_Java_thread()) {
411 // Initialize the thread state to RUNNABLE before starting this thread.
412 // Can not set it after the thread started because we do not know the
413 // exact thread state at that time. It could be in MONITOR_WAIT or
414 // in SLEEPING or some other state.
415 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
416 java_lang_Thread::RUNNABLE);
417 }
418 os::start_thread(thread);
419 }
420 }
421
422 // Enqueue a VM_Operation to do the job for us - sometime later
423 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
424 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
425 VMThread::execute(vm_stop);
426 }
427
428
429 // Check if an external suspend request has completed (or has been
430 // cancelled). Returns true if the thread is externally suspended and
431 // false otherwise.
432 //
433 // The bits parameter returns information about the code path through
434 // the routine. Useful for debugging:
435 //
436 // set in is_ext_suspend_completed():
437 // 0x00000001 - routine was entered
438 // 0x00000010 - routine return false at end
439 // 0x00000100 - thread exited (return false)
440 // 0x00000200 - suspend request cancelled (return false)
441 // 0x00000400 - thread suspended (return true)
442 // 0x00001000 - thread is in a suspend equivalent state (return true)
443 // 0x00002000 - thread is native and walkable (return true)
444 // 0x00004000 - thread is native_trans and walkable (needed retry)
445 //
446 // set in wait_for_ext_suspend_completion():
447 // 0x00010000 - routine was entered
448 // 0x00020000 - suspend request cancelled before loop (return false)
449 // 0x00040000 - thread suspended before loop (return true)
450 // 0x00080000 - suspend request cancelled in loop (return false)
451 // 0x00100000 - thread suspended in loop (return true)
452 // 0x00200000 - suspend not completed during retry loop (return false)
453
454 // Helper class for tracing suspend wait debug bits.
455 //
456 // 0x00000100 indicates that the target thread exited before it could
457 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
458 // 0x00080000 each indicate a cancelled suspend request so they don't
459 // count as wait failures either.
460 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
461
462 class TraceSuspendDebugBits : public StackObj {
463 private:
464 JavaThread * jt;
465 bool is_wait;
466 bool called_by_wait; // meaningful when !is_wait
467 uint32_t * bits;
468
469 public:
470 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
471 uint32_t *_bits) {
472 jt = _jt;
473 is_wait = _is_wait;
474 called_by_wait = _called_by_wait;
475 bits = _bits;
476 }
477
478 ~TraceSuspendDebugBits() {
479 if (!is_wait) {
480 #if 1
481 // By default, don't trace bits for is_ext_suspend_completed() calls.
482 // That trace is very chatty.
483 return;
484 #else
485 if (!called_by_wait) {
486 // If tracing for is_ext_suspend_completed() is enabled, then only
487 // trace calls to it from wait_for_ext_suspend_completion()
488 return;
489 }
490 #endif
491 }
492
493 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
494 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
495 MutexLocker ml(Threads_lock); // needed for get_thread_name()
496 ResourceMark rm;
497
498 tty->print_cr(
499 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
500 jt->get_thread_name(), *bits);
501
502 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
503 }
504 }
505 }
506 };
507 #undef DEBUG_FALSE_BITS
508
509
510 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
511 uint32_t *bits) {
512 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
513
514 bool did_trans_retry = false; // only do thread_in_native_trans retry once
515 bool do_trans_retry; // flag to force the retry
516
517 *bits |= 0x00000001;
518
519 do {
520 do_trans_retry = false;
521
522 if (is_exiting()) {
523 // Thread is in the process of exiting. This is always checked
524 // first to reduce the risk of dereferencing a freed JavaThread.
525 *bits |= 0x00000100;
526 return false;
527 }
528
529 if (!is_external_suspend()) {
530 // Suspend request is cancelled. This is always checked before
531 // is_ext_suspended() to reduce the risk of a rogue resume
532 // confusing the thread that made the suspend request.
533 *bits |= 0x00000200;
534 return false;
535 }
536
537 if (is_ext_suspended()) {
538 // thread is suspended
539 *bits |= 0x00000400;
540 return true;
541 }
542
543 // Now that we no longer do hard suspends of threads running
544 // native code, the target thread can be changing thread state
545 // while we are in this routine:
546 //
547 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
548 //
549 // We save a copy of the thread state as observed at this moment
550 // and make our decision about suspend completeness based on the
551 // copy. This closes the race where the thread state is seen as
552 // _thread_in_native_trans in the if-thread_blocked check, but is
553 // seen as _thread_blocked in if-thread_in_native_trans check.
554 JavaThreadState save_state = thread_state();
555
556 if (save_state == _thread_blocked && is_suspend_equivalent()) {
557 // If the thread's state is _thread_blocked and this blocking
558 // condition is known to be equivalent to a suspend, then we can
559 // consider the thread to be externally suspended. This means that
560 // the code that sets _thread_blocked has been modified to do
561 // self-suspension if the blocking condition releases. We also
562 // used to check for CONDVAR_WAIT here, but that is now covered by
563 // the _thread_blocked with self-suspension check.
564 //
565 // Return true since we wouldn't be here unless there was still an
566 // external suspend request.
567 *bits |= 0x00001000;
568 return true;
569 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
570 // Threads running native code will self-suspend on native==>VM/Java
571 // transitions. If its stack is walkable (should always be the case
572 // unless this function is called before the actual java_suspend()
573 // call), then the wait is done.
574 *bits |= 0x00002000;
575 return true;
576 } else if (!called_by_wait && !did_trans_retry &&
577 save_state == _thread_in_native_trans &&
578 frame_anchor()->walkable()) {
579 // The thread is transitioning from thread_in_native to another
580 // thread state. check_safepoint_and_suspend_for_native_trans()
581 // will force the thread to self-suspend. If it hasn't gotten
582 // there yet we may have caught the thread in-between the native
583 // code check above and the self-suspend. Lucky us. If we were
584 // called by wait_for_ext_suspend_completion(), then it
585 // will be doing the retries so we don't have to.
586 //
587 // Since we use the saved thread state in the if-statement above,
588 // there is a chance that the thread has already transitioned to
589 // _thread_blocked by the time we get here. In that case, we will
590 // make a single unnecessary pass through the logic below. This
591 // doesn't hurt anything since we still do the trans retry.
592
593 *bits |= 0x00004000;
594
595 // Once the thread leaves thread_in_native_trans for another
596 // thread state, we break out of this retry loop. We shouldn't
597 // need this flag to prevent us from getting back here, but
598 // sometimes paranoia is good.
599 did_trans_retry = true;
600
601 // We wait for the thread to transition to a more usable state.
602 for (int i = 1; i <= SuspendRetryCount; i++) {
603 // We used to do an "os::yield_all(i)" call here with the intention
604 // that yielding would increase on each retry. However, the parameter
605 // is ignored on Linux which means the yield didn't scale up. Waiting
606 // on the SR_lock below provides a much more predictable scale up for
607 // the delay. It also provides a simple/direct point to check for any
608 // safepoint requests from the VMThread
609
610 // temporarily drops SR_lock while doing wait with safepoint check
611 // (if we're a JavaThread - the WatcherThread can also call this)
612 // and increase delay with each retry
613 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
614
615 // check the actual thread state instead of what we saved above
616 if (thread_state() != _thread_in_native_trans) {
617 // the thread has transitioned to another thread state so
618 // try all the checks (except this one) one more time.
619 do_trans_retry = true;
620 break;
621 }
622 } // end retry loop
623
624
625 }
626 } while (do_trans_retry);
627
628 *bits |= 0x00000010;
629 return false;
630 }
631
632 // Wait for an external suspend request to complete (or be cancelled).
633 // Returns true if the thread is externally suspended and false otherwise.
634 //
635 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
636 uint32_t *bits) {
637 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
638 false /* !called_by_wait */, bits);
639
640 // local flag copies to minimize SR_lock hold time
641 bool is_suspended;
642 bool pending;
643 uint32_t reset_bits;
644
645 // set a marker so is_ext_suspend_completed() knows we are the caller
646 *bits |= 0x00010000;
647
648 // We use reset_bits to reinitialize the bits value at the top of
649 // each retry loop. This allows the caller to make use of any
650 // unused bits for their own marking purposes.
651 reset_bits = *bits;
652
653 {
654 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
655 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
656 delay, bits);
657 pending = is_external_suspend();
658 }
659 // must release SR_lock to allow suspension to complete
660
661 if (!pending) {
662 // A cancelled suspend request is the only false return from
663 // is_ext_suspend_completed() that keeps us from entering the
664 // retry loop.
665 *bits |= 0x00020000;
666 return false;
667 }
668
669 if (is_suspended) {
670 *bits |= 0x00040000;
671 return true;
672 }
673
674 for (int i = 1; i <= retries; i++) {
675 *bits = reset_bits; // reinit to only track last retry
676
677 // We used to do an "os::yield_all(i)" call here with the intention
678 // that yielding would increase on each retry. However, the parameter
679 // is ignored on Linux which means the yield didn't scale up. Waiting
680 // on the SR_lock below provides a much more predictable scale up for
681 // the delay. It also provides a simple/direct point to check for any
682 // safepoint requests from the VMThread
683
684 {
685 MutexLocker ml(SR_lock());
686 // wait with safepoint check (if we're a JavaThread - the WatcherThread
687 // can also call this) and increase delay with each retry
688 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
689
690 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
691 delay, bits);
692
693 // It is possible for the external suspend request to be cancelled
694 // (by a resume) before the actual suspend operation is completed.
695 // Refresh our local copy to see if we still need to wait.
696 pending = is_external_suspend();
697 }
698
699 if (!pending) {
700 // A cancelled suspend request is the only false return from
701 // is_ext_suspend_completed() that keeps us from staying in the
702 // retry loop.
703 *bits |= 0x00080000;
704 return false;
705 }
706
707 if (is_suspended) {
708 *bits |= 0x00100000;
709 return true;
710 }
711 } // end retry loop
712
713 // thread did not suspend after all our retries
714 *bits |= 0x00200000;
715 return false;
716 }
717
718 #ifndef PRODUCT
719 void JavaThread::record_jump(address target, address instr, const char* file,
720 int line) {
721
722 // This should not need to be atomic as the only way for simultaneous
723 // updates is via interrupts. Even then this should be rare or non-existent
724 // and we don't care that much anyway.
725
726 int index = _jmp_ring_index;
727 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
728 _jmp_ring[index]._target = (intptr_t) target;
729 _jmp_ring[index]._instruction = (intptr_t) instr;
730 _jmp_ring[index]._file = file;
731 _jmp_ring[index]._line = line;
732 }
733 #endif // PRODUCT
734
735 // Called by flat profiler
736 // Callers have already called wait_for_ext_suspend_completion
737 // The assertion for that is currently too complex to put here:
738 bool JavaThread::profile_last_Java_frame(frame* _fr) {
739 bool gotframe = false;
740 // self suspension saves needed state.
741 if (has_last_Java_frame() && _anchor.walkable()) {
742 *_fr = pd_last_frame();
743 gotframe = true;
744 }
745 return gotframe;
746 }
747
748 void Thread::interrupt(Thread* thread) {
749 debug_only(check_for_dangling_thread_pointer(thread);)
750 os::interrupt(thread);
751 }
752
753 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
754 debug_only(check_for_dangling_thread_pointer(thread);)
755 // Note: If clear_interrupted==false, this simply fetches and
756 // returns the value of the field osthread()->interrupted().
757 return os::is_interrupted(thread, clear_interrupted);
758 }
759
760
761 // GC Support
762 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
763 jint thread_parity = _oops_do_parity;
764 if (thread_parity != strong_roots_parity) {
765 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
766 if (res == thread_parity) {
767 return true;
768 } else {
769 guarantee(res == strong_roots_parity, "Or else what?");
770 return false;
771 }
772 }
773 return false;
774 }
775
776 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
777 active_handles()->oops_do(f);
778 // Do oop for ThreadShadow
779 f->do_oop((oop*)&_pending_exception);
780 handle_area()->oops_do(f);
781 }
782
783 void Thread::nmethods_do(CodeBlobClosure* cf) {
784 // no nmethods in a generic thread...
785 }
786
787 void Thread::metadata_handles_do(void f(Metadata*)) {
788 // Only walk the Handles in Thread.
789 if (metadata_handles() != NULL) {
790 for (int i = 0; i< metadata_handles()->length(); i++) {
791 f(metadata_handles()->at(i));
792 }
793 }
794 }
795
796 void Thread::print_on(outputStream* st) const {
797 // get_priority assumes osthread initialized
798 if (osthread() != NULL) {
799 int os_prio;
800 if (os::get_native_priority(this, &os_prio) == OS_OK) {
801 st->print("os_prio=%d ", os_prio);
802 }
803 st->print("tid=" INTPTR_FORMAT " ", this);
804 ext().print_on(st);
805 osthread()->print_on(st);
806 }
807 debug_only(if (WizardMode) print_owned_locks_on(st);)
808 }
809
810 // Thread::print_on_error() is called by fatal error handler. Don't use
811 // any lock or allocate memory.
812 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
813 if (is_VM_thread()) st->print("VMThread");
814 else if (is_Compiler_thread()) st->print("CompilerThread");
815 else if (is_Java_thread()) st->print("JavaThread");
816 else if (is_GC_task_thread()) st->print("GCTaskThread");
817 else if (is_Watcher_thread()) st->print("WatcherThread");
818 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
819 else st->print("Thread");
820
821 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
822 _stack_base - _stack_size, _stack_base);
823
824 if (osthread()) {
825 st->print(" [id=%d]", osthread()->thread_id());
826 }
827 }
828
829 #ifdef ASSERT
830 void Thread::print_owned_locks_on(outputStream* st) const {
831 Monitor *cur = _owned_locks;
832 if (cur == NULL) {
833 st->print(" (no locks) ");
834 } else {
835 st->print_cr(" Locks owned:");
836 while (cur) {
837 cur->print_on(st);
838 cur = cur->next();
839 }
840 }
841 }
842
843 static int ref_use_count = 0;
844
845 bool Thread::owns_locks_but_compiled_lock() const {
846 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
847 if (cur != Compile_lock) return true;
848 }
849 return false;
850 }
851
852
853 #endif
854
855 #ifndef PRODUCT
856
857 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
858 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
859 // no threads which allow_vm_block's are held
860 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
861 // Check if current thread is allowed to block at a safepoint
862 if (!(_allow_safepoint_count == 0)) {
863 fatal("Possible safepoint reached by thread that does not allow it");
864 }
865 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
866 fatal("LEAF method calling lock?");
867 }
868
869 #ifdef ASSERT
870 if (potential_vm_operation && is_Java_thread()
871 && !Universe::is_bootstrapping()) {
872 // Make sure we do not hold any locks that the VM thread also uses.
873 // This could potentially lead to deadlocks
874 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
875 // Threads_lock is special, since the safepoint synchronization will not start before this is
876 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
877 // since it is used to transfer control between JavaThreads and the VMThread
878 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
879 if ((cur->allow_vm_block() &&
880 cur != Threads_lock &&
881 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
882 cur != VMOperationRequest_lock &&
883 cur != VMOperationQueue_lock) ||
884 cur->rank() == Mutex::special) {
885 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
886 }
887 }
888 }
889
890 if (GCALotAtAllSafepoints) {
891 // We could enter a safepoint here and thus have a gc
892 InterfaceSupport::check_gc_alot();
893 }
894 #endif
895 }
896 #endif
897
898 bool Thread::is_in_stack(address adr) const {
899 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
900 address end = os::current_stack_pointer();
901 // Allow non Java threads to call this without stack_base
902 if (_stack_base == NULL) return true;
903 if (stack_base() >= adr && adr >= end) return true;
904
905 return false;
906 }
907
908
909 bool Thread::is_in_usable_stack(address adr) const {
910 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
911 size_t usable_stack_size = _stack_size - stack_guard_size;
912
913 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
914 }
915
916
917 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
918 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
919 // used for compilation in the future. If that change is made, the need for these methods
920 // should be revisited, and they should be removed if possible.
921
922 bool Thread::is_lock_owned(address adr) const {
923 return on_local_stack(adr);
924 }
925
926 bool Thread::set_as_starting_thread() {
927 // NOTE: this must be called inside the main thread.
928 return os::create_main_thread((JavaThread*)this);
929 }
930
931 static void initialize_class(Symbol* class_name, TRAPS) {
932 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
933 InstanceKlass::cast(klass)->initialize(CHECK);
934 }
935
936
937 // Creates the initial ThreadGroup
938 static Handle create_initial_thread_group(TRAPS) {
939 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
940 instanceKlassHandle klass (THREAD, k);
941
942 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
943 {
944 JavaValue result(T_VOID);
945 JavaCalls::call_special(&result,
946 system_instance,
947 klass,
948 vmSymbols::object_initializer_name(),
949 vmSymbols::void_method_signature(),
950 CHECK_NH);
951 }
952 Universe::set_system_thread_group(system_instance());
953
954 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
955 {
956 JavaValue result(T_VOID);
957 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
958 JavaCalls::call_special(&result,
959 main_instance,
960 klass,
961 vmSymbols::object_initializer_name(),
962 vmSymbols::threadgroup_string_void_signature(),
963 system_instance,
964 string,
965 CHECK_NH);
966 }
967 return main_instance;
968 }
969
970 // Creates the initial Thread
971 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
972 TRAPS) {
973 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
974 instanceKlassHandle klass (THREAD, k);
975 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
976
977 java_lang_Thread::set_thread(thread_oop(), thread);
978 java_lang_Thread::set_priority(thread_oop(), NormPriority);
979 thread->set_threadObj(thread_oop());
980
981 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
982
983 JavaValue result(T_VOID);
984 JavaCalls::call_special(&result, thread_oop,
985 klass,
986 vmSymbols::object_initializer_name(),
987 vmSymbols::threadgroup_string_void_signature(),
988 thread_group,
989 string,
990 CHECK_NULL);
991 return thread_oop();
992 }
993
994 static void call_initializeSystemClass(TRAPS) {
995 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
996 instanceKlassHandle klass (THREAD, k);
997
998 JavaValue result(T_VOID);
999 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1000 vmSymbols::void_method_signature(), CHECK);
1001 }
1002
1003 char java_runtime_name[128] = "";
1004 char java_runtime_version[128] = "";
1005
1006 // extract the JRE name from sun.misc.Version.java_runtime_name
1007 static const char* get_java_runtime_name(TRAPS) {
1008 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1009 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1010 fieldDescriptor fd;
1011 bool found = k != NULL &&
1012 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1013 vmSymbols::string_signature(), &fd);
1014 if (found) {
1015 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1016 if (name_oop == NULL) {
1017 return NULL;
1018 }
1019 const char* name = java_lang_String::as_utf8_string(name_oop,
1020 java_runtime_name,
1021 sizeof(java_runtime_name));
1022 return name;
1023 } else {
1024 return NULL;
1025 }
1026 }
1027
1028 // extract the JRE version from sun.misc.Version.java_runtime_version
1029 static const char* get_java_runtime_version(TRAPS) {
1030 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1031 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1032 fieldDescriptor fd;
1033 bool found = k != NULL &&
1034 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1035 vmSymbols::string_signature(), &fd);
1036 if (found) {
1037 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1038 if (name_oop == NULL) {
1039 return NULL;
1040 }
1041 const char* name = java_lang_String::as_utf8_string(name_oop,
1042 java_runtime_version,
1043 sizeof(java_runtime_version));
1044 return name;
1045 } else {
1046 return NULL;
1047 }
1048 }
1049
1050 // General purpose hook into Java code, run once when the VM is initialized.
1051 // The Java library method itself may be changed independently from the VM.
1052 static void call_postVMInitHook(TRAPS) {
1053 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1054 instanceKlassHandle klass (THREAD, k);
1055 if (klass.not_null()) {
1056 JavaValue result(T_VOID);
1057 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1058 vmSymbols::void_method_signature(),
1059 CHECK);
1060 }
1061 }
1062
1063 static void reset_vm_info_property(TRAPS) {
1064 // the vm info string
1065 ResourceMark rm(THREAD);
1066 const char *vm_info = VM_Version::vm_info_string();
1067
1068 // java.lang.System class
1069 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1070 instanceKlassHandle klass (THREAD, k);
1071
1072 // setProperty arguments
1073 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1074 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1075
1076 // return value
1077 JavaValue r(T_OBJECT);
1078
1079 // public static String setProperty(String key, String value);
1080 JavaCalls::call_static(&r,
1081 klass,
1082 vmSymbols::setProperty_name(),
1083 vmSymbols::string_string_string_signature(),
1084 key_str,
1085 value_str,
1086 CHECK);
1087 }
1088
1089
1090 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1091 bool daemon, TRAPS) {
1092 assert(thread_group.not_null(), "thread group should be specified");
1093 assert(threadObj() == NULL, "should only create Java thread object once");
1094
1095 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1096 instanceKlassHandle klass (THREAD, k);
1097 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1098
1099 java_lang_Thread::set_thread(thread_oop(), this);
1100 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1101 set_threadObj(thread_oop());
1102
1103 JavaValue result(T_VOID);
1104 if (thread_name != NULL) {
1105 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1106 // Thread gets assigned specified name and null target
1107 JavaCalls::call_special(&result,
1108 thread_oop,
1109 klass,
1110 vmSymbols::object_initializer_name(),
1111 vmSymbols::threadgroup_string_void_signature(),
1112 thread_group, // Argument 1
1113 name, // Argument 2
1114 THREAD);
1115 } else {
1116 // Thread gets assigned name "Thread-nnn" and null target
1117 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1118 JavaCalls::call_special(&result,
1119 thread_oop,
1120 klass,
1121 vmSymbols::object_initializer_name(),
1122 vmSymbols::threadgroup_runnable_void_signature(),
1123 thread_group, // Argument 1
1124 Handle(), // Argument 2
1125 THREAD);
1126 }
1127
1128
1129 if (daemon) {
1130 java_lang_Thread::set_daemon(thread_oop());
1131 }
1132
1133 if (HAS_PENDING_EXCEPTION) {
1134 return;
1135 }
1136
1137 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1138 Handle threadObj(THREAD, this->threadObj());
1139
1140 JavaCalls::call_special(&result,
1141 thread_group,
1142 group,
1143 vmSymbols::add_method_name(),
1144 vmSymbols::thread_void_signature(),
1145 threadObj, // Arg 1
1146 THREAD);
1147 }
1148
1149 // NamedThread -- non-JavaThread subclasses with multiple
1150 // uniquely named instances should derive from this.
1151 NamedThread::NamedThread() : Thread() {
1152 _name = NULL;
1153 _processed_thread = NULL;
1154 }
1155
1156 NamedThread::~NamedThread() {
1157 if (_name != NULL) {
1158 FREE_C_HEAP_ARRAY(char, _name);
1159 _name = NULL;
1160 }
1161 }
1162
1163 void NamedThread::set_name(const char* format, ...) {
1164 guarantee(_name == NULL, "Only get to set name once.");
1165 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1166 guarantee(_name != NULL, "alloc failure");
1167 va_list ap;
1168 va_start(ap, format);
1169 jio_vsnprintf(_name, max_name_len, format, ap);
1170 va_end(ap);
1171 }
1172
1173 void NamedThread::initialize_named_thread() {
1174 set_native_thread_name(name());
1175 }
1176
1177 void NamedThread::print_on(outputStream* st) const {
1178 st->print("\"%s\" ", name());
1179 Thread::print_on(st);
1180 st->cr();
1181 }
1182
1183
1184 // ======= WatcherThread ========
1185
1186 // The watcher thread exists to simulate timer interrupts. It should
1187 // be replaced by an abstraction over whatever native support for
1188 // timer interrupts exists on the platform.
1189
1190 WatcherThread* WatcherThread::_watcher_thread = NULL;
1191 bool WatcherThread::_startable = false;
1192 volatile bool WatcherThread::_should_terminate = false;
1193
1194 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1195 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1196 if (os::create_thread(this, os::watcher_thread)) {
1197 _watcher_thread = this;
1198
1199 // Set the watcher thread to the highest OS priority which should not be
1200 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1201 // is created. The only normal thread using this priority is the reference
1202 // handler thread, which runs for very short intervals only.
1203 // If the VMThread's priority is not lower than the WatcherThread profiling
1204 // will be inaccurate.
1205 os::set_priority(this, MaxPriority);
1206 if (!DisableStartThread) {
1207 os::start_thread(this);
1208 }
1209 }
1210 }
1211
1212 int WatcherThread::sleep() const {
1213 // The WatcherThread does not participate in the safepoint protocol
1214 // for the PeriodicTask_lock because it is not a JavaThread.
1215 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1216
1217 if (_should_terminate) {
1218 // check for termination before we do any housekeeping or wait
1219 return 0; // we did not sleep.
1220 }
1221
1222 // remaining will be zero if there are no tasks,
1223 // causing the WatcherThread to sleep until a task is
1224 // enrolled
1225 int remaining = PeriodicTask::time_to_wait();
1226 int time_slept = 0;
1227
1228 // we expect this to timeout - we only ever get unparked when
1229 // we should terminate or when a new task has been enrolled
1230 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1231
1232 jlong time_before_loop = os::javaTimeNanos();
1233
1234 while (true) {
1235 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1236 remaining);
1237 jlong now = os::javaTimeNanos();
1238
1239 if (remaining == 0) {
1240 // if we didn't have any tasks we could have waited for a long time
1241 // consider the time_slept zero and reset time_before_loop
1242 time_slept = 0;
1243 time_before_loop = now;
1244 } else {
1245 // need to recalculate since we might have new tasks in _tasks
1246 time_slept = (int) ((now - time_before_loop) / 1000000);
1247 }
1248
1249 // Change to task list or spurious wakeup of some kind
1250 if (timedout || _should_terminate) {
1251 break;
1252 }
1253
1254 remaining = PeriodicTask::time_to_wait();
1255 if (remaining == 0) {
1256 // Last task was just disenrolled so loop around and wait until
1257 // another task gets enrolled
1258 continue;
1259 }
1260
1261 remaining -= time_slept;
1262 if (remaining <= 0) {
1263 break;
1264 }
1265 }
1266
1267 return time_slept;
1268 }
1269
1270 void WatcherThread::run() {
1271
1272 assert(this == watcher_thread(), "just checking");
1273
1274 this->record_stack_base_and_size();
1275 this->initialize_thread_local_storage();
1276 this->set_native_thread_name(this->name());
1277 this->set_active_handles(JNIHandleBlock::allocate_block());
1278 while (true) {
1279 assert(watcher_thread() == Thread::current(), "thread consistency check");
1280 assert(watcher_thread() == this, "thread consistency check");
1281
1282 // Calculate how long it'll be until the next PeriodicTask work
1283 // should be done, and sleep that amount of time.
1284 int time_waited = sleep();
1285
1286 if (is_error_reported()) {
1287 // A fatal error has happened, the error handler(VMError::report_and_die)
1288 // should abort JVM after creating an error log file. However in some
1289 // rare cases, the error handler itself might deadlock. Here we try to
1290 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1291 //
1292 // This code is in WatcherThread because WatcherThread wakes up
1293 // periodically so the fatal error handler doesn't need to do anything;
1294 // also because the WatcherThread is less likely to crash than other
1295 // threads.
1296
1297 for (;;) {
1298 if (!ShowMessageBoxOnError
1299 && (OnError == NULL || OnError[0] == '\0')
1300 && Arguments::abort_hook() == NULL) {
1301 os::sleep(this, ErrorLogTimeout * 60 * 1000, false);
1302 fdStream err(defaultStream::output_fd());
1303 err.print_raw_cr("# [ timer expired, abort... ]");
1304 // skip atexit/vm_exit/vm_abort hooks
1305 os::die();
1306 }
1307
1308 // Wake up 5 seconds later, the fatal handler may reset OnError or
1309 // ShowMessageBoxOnError when it is ready to abort.
1310 os::sleep(this, 5 * 1000, false);
1311 }
1312 }
1313
1314 if (_should_terminate) {
1315 // check for termination before posting the next tick
1316 break;
1317 }
1318
1319 PeriodicTask::real_time_tick(time_waited);
1320 }
1321
1322 // Signal that it is terminated
1323 {
1324 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1325 _watcher_thread = NULL;
1326 Terminator_lock->notify();
1327 }
1328
1329 // Thread destructor usually does this..
1330 ThreadLocalStorage::set_thread(NULL);
1331 }
1332
1333 void WatcherThread::start() {
1334 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1335
1336 if (watcher_thread() == NULL && _startable) {
1337 _should_terminate = false;
1338 // Create the single instance of WatcherThread
1339 new WatcherThread();
1340 }
1341 }
1342
1343 void WatcherThread::make_startable() {
1344 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1345 _startable = true;
1346 }
1347
1348 void WatcherThread::stop() {
1349 {
1350 // Follow normal safepoint aware lock enter protocol since the
1351 // WatcherThread is stopped by another JavaThread.
1352 MutexLocker ml(PeriodicTask_lock);
1353 _should_terminate = true;
1354
1355 WatcherThread* watcher = watcher_thread();
1356 if (watcher != NULL) {
1357 // unpark the WatcherThread so it can see that it should terminate
1358 watcher->unpark();
1359 }
1360 }
1361
1362 MutexLocker mu(Terminator_lock);
1363
1364 while (watcher_thread() != NULL) {
1365 // This wait should make safepoint checks, wait without a timeout,
1366 // and wait as a suspend-equivalent condition.
1367 //
1368 // Note: If the FlatProfiler is running, then this thread is waiting
1369 // for the WatcherThread to terminate and the WatcherThread, via the
1370 // FlatProfiler task, is waiting for the external suspend request on
1371 // this thread to complete. wait_for_ext_suspend_completion() will
1372 // eventually timeout, but that takes time. Making this wait a
1373 // suspend-equivalent condition solves that timeout problem.
1374 //
1375 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1376 Mutex::_as_suspend_equivalent_flag);
1377 }
1378 }
1379
1380 void WatcherThread::unpark() {
1381 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1382 PeriodicTask_lock->notify();
1383 }
1384
1385 void WatcherThread::print_on(outputStream* st) const {
1386 st->print("\"%s\" ", name());
1387 Thread::print_on(st);
1388 st->cr();
1389 }
1390
1391 // ======= JavaThread ========
1392
1393 // A JavaThread is a normal Java thread
1394
1395 void JavaThread::initialize() {
1396 // Initialize fields
1397
1398 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1399 set_claimed_par_id(UINT_MAX);
1400
1401 set_saved_exception_pc(NULL);
1402 set_threadObj(NULL);
1403 _anchor.clear();
1404 set_entry_point(NULL);
1405 set_jni_functions(jni_functions());
1406 set_callee_target(NULL);
1407 set_vm_result(NULL);
1408 set_vm_result_2(NULL);
1409 set_vframe_array_head(NULL);
1410 set_vframe_array_last(NULL);
1411 set_deferred_locals(NULL);
1412 set_deopt_mark(NULL);
1413 set_deopt_nmethod(NULL);
1414 clear_must_deopt_id();
1415 set_monitor_chunks(NULL);
1416 set_next(NULL);
1417 set_thread_state(_thread_new);
1418 _terminated = _not_terminated;
1419 _privileged_stack_top = NULL;
1420 _array_for_gc = NULL;
1421 _suspend_equivalent = false;
1422 _in_deopt_handler = 0;
1423 _doing_unsafe_access = false;
1424 _stack_guard_state = stack_guard_unused;
1425 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1426 _exception_pc = 0;
1427 _exception_handler_pc = 0;
1428 _is_method_handle_return = 0;
1429 _jvmti_thread_state= NULL;
1430 _should_post_on_exceptions_flag = JNI_FALSE;
1431 _jvmti_get_loaded_classes_closure = NULL;
1432 _interp_only_mode = 0;
1433 _special_runtime_exit_condition = _no_async_condition;
1434 _pending_async_exception = NULL;
1435 _thread_stat = NULL;
1436 _thread_stat = new ThreadStatistics();
1437 _blocked_on_compilation = false;
1438 _jni_active_critical = 0;
1439 _pending_jni_exception_check_fn = NULL;
1440 _do_not_unlock_if_synchronized = false;
1441 _cached_monitor_info = NULL;
1442 _parker = Parker::Allocate(this);
1443
1444 #ifndef PRODUCT
1445 _jmp_ring_index = 0;
1446 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1447 record_jump(NULL, NULL, NULL, 0);
1448 }
1449 #endif // PRODUCT
1450
1451 set_thread_profiler(NULL);
1452 if (FlatProfiler::is_active()) {
1453 // This is where we would decide to either give each thread it's own profiler
1454 // or use one global one from FlatProfiler,
1455 // or up to some count of the number of profiled threads, etc.
1456 ThreadProfiler* pp = new ThreadProfiler();
1457 pp->engage();
1458 set_thread_profiler(pp);
1459 }
1460
1461 // Setup safepoint state info for this thread
1462 ThreadSafepointState::create(this);
1463
1464 debug_only(_java_call_counter = 0);
1465
1466 // JVMTI PopFrame support
1467 _popframe_condition = popframe_inactive;
1468 _popframe_preserved_args = NULL;
1469 _popframe_preserved_args_size = 0;
1470 _frames_to_pop_failed_realloc = 0;
1471
1472 pd_initialize();
1473 }
1474
1475 #if INCLUDE_ALL_GCS
1476 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1477 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1478 bool JavaThread::_evacuation_in_progress_global = false;
1479 #endif // INCLUDE_ALL_GCS
1480
1481 JavaThread::JavaThread(bool is_attaching_via_jni) :
1482 Thread()
1483 #if INCLUDE_ALL_GCS
1484 , _satb_mark_queue(&_satb_mark_queue_set),
1485 _dirty_card_queue(&_dirty_card_queue_set),
1486 _evacuation_in_progress(_evacuation_in_progress_global)
1487 #endif // INCLUDE_ALL_GCS
1488 {
1489 initialize();
1490 if (is_attaching_via_jni) {
1491 _jni_attach_state = _attaching_via_jni;
1492 } else {
1493 _jni_attach_state = _not_attaching_via_jni;
1494 }
1495 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1496 }
1497
1498 bool JavaThread::reguard_stack(address cur_sp) {
1499 if (_stack_guard_state != stack_guard_yellow_disabled) {
1500 return true; // Stack already guarded or guard pages not needed.
1501 }
1502
1503 if (register_stack_overflow()) {
1504 // For those architectures which have separate register and
1505 // memory stacks, we must check the register stack to see if
1506 // it has overflowed.
1507 return false;
1508 }
1509
1510 // Java code never executes within the yellow zone: the latter is only
1511 // there to provoke an exception during stack banging. If java code
1512 // is executing there, either StackShadowPages should be larger, or
1513 // some exception code in c1, c2 or the interpreter isn't unwinding
1514 // when it should.
1515 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1516
1517 enable_stack_yellow_zone();
1518 return true;
1519 }
1520
1521 bool JavaThread::reguard_stack(void) {
1522 return reguard_stack(os::current_stack_pointer());
1523 }
1524
1525
1526 void JavaThread::block_if_vm_exited() {
1527 if (_terminated == _vm_exited) {
1528 // _vm_exited is set at safepoint, and Threads_lock is never released
1529 // we will block here forever
1530 Threads_lock->lock_without_safepoint_check();
1531 ShouldNotReachHere();
1532 }
1533 }
1534
1535
1536 // Remove this ifdef when C1 is ported to the compiler interface.
1537 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1538 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1539
1540 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1541 Thread()
1542 #if INCLUDE_ALL_GCS
1543 , _satb_mark_queue(&_satb_mark_queue_set),
1544 _dirty_card_queue(&_dirty_card_queue_set),
1545 _evacuation_in_progress(_evacuation_in_progress_global)
1546 #endif // INCLUDE_ALL_GCS
1547 {
1548 initialize();
1549 _jni_attach_state = _not_attaching_via_jni;
1550 set_entry_point(entry_point);
1551 // Create the native thread itself.
1552 // %note runtime_23
1553 os::ThreadType thr_type = os::java_thread;
1554 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1555 os::java_thread;
1556 os::create_thread(this, thr_type, stack_sz);
1557 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1558 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1559 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1560 // the exception consists of creating the exception object & initializing it, initialization
1561 // will leave the VM via a JavaCall and then all locks must be unlocked).
1562 //
1563 // The thread is still suspended when we reach here. Thread must be explicit started
1564 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1565 // by calling Threads:add. The reason why this is not done here, is because the thread
1566 // object must be fully initialized (take a look at JVM_Start)
1567 }
1568
1569 JavaThread::~JavaThread() {
1570
1571 // JSR166 -- return the parker to the free list
1572 Parker::Release(_parker);
1573 _parker = NULL;
1574
1575 // Free any remaining previous UnrollBlock
1576 vframeArray* old_array = vframe_array_last();
1577
1578 if (old_array != NULL) {
1579 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1580 old_array->set_unroll_block(NULL);
1581 delete old_info;
1582 delete old_array;
1583 }
1584
1585 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1586 if (deferred != NULL) {
1587 // This can only happen if thread is destroyed before deoptimization occurs.
1588 assert(deferred->length() != 0, "empty array!");
1589 do {
1590 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1591 deferred->remove_at(0);
1592 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1593 delete dlv;
1594 } while (deferred->length() != 0);
1595 delete deferred;
1596 }
1597
1598 // All Java related clean up happens in exit
1599 ThreadSafepointState::destroy(this);
1600 if (_thread_profiler != NULL) delete _thread_profiler;
1601 if (_thread_stat != NULL) delete _thread_stat;
1602 }
1603
1604
1605 // The first routine called by a new Java thread
1606 void JavaThread::run() {
1607 // initialize thread-local alloc buffer related fields
1608 this->initialize_tlab();
1609
1610 // used to test validity of stack trace backs
1611 this->record_base_of_stack_pointer();
1612
1613 // Record real stack base and size.
1614 this->record_stack_base_and_size();
1615
1616 // Initialize thread local storage; set before calling MutexLocker
1617 this->initialize_thread_local_storage();
1618
1619 this->create_stack_guard_pages();
1620
1621 this->cache_global_variables();
1622
1623 // Thread is now sufficient initialized to be handled by the safepoint code as being
1624 // in the VM. Change thread state from _thread_new to _thread_in_vm
1625 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1626
1627 assert(JavaThread::current() == this, "sanity check");
1628 assert(!Thread::current()->owns_locks(), "sanity check");
1629
1630 DTRACE_THREAD_PROBE(start, this);
1631
1632 // This operation might block. We call that after all safepoint checks for a new thread has
1633 // been completed.
1634 this->set_active_handles(JNIHandleBlock::allocate_block());
1635
1636 if (JvmtiExport::should_post_thread_life()) {
1637 JvmtiExport::post_thread_start(this);
1638 }
1639
1640 EventThreadStart event;
1641 if (event.should_commit()) {
1642 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1643 event.commit();
1644 }
1645
1646 // We call another function to do the rest so we are sure that the stack addresses used
1647 // from there will be lower than the stack base just computed
1648 thread_main_inner();
1649
1650 // Note, thread is no longer valid at this point!
1651 }
1652
1653
1654 void JavaThread::thread_main_inner() {
1655 assert(JavaThread::current() == this, "sanity check");
1656 assert(this->threadObj() != NULL, "just checking");
1657
1658 // Execute thread entry point unless this thread has a pending exception
1659 // or has been stopped before starting.
1660 // Note: Due to JVM_StopThread we can have pending exceptions already!
1661 if (!this->has_pending_exception() &&
1662 !java_lang_Thread::is_stillborn(this->threadObj())) {
1663 {
1664 ResourceMark rm(this);
1665 this->set_native_thread_name(this->get_thread_name());
1666 }
1667 HandleMark hm(this);
1668 this->entry_point()(this, this);
1669 }
1670
1671 DTRACE_THREAD_PROBE(stop, this);
1672
1673 this->exit(false);
1674 delete this;
1675 }
1676
1677
1678 static void ensure_join(JavaThread* thread) {
1679 // We do not need to grap the Threads_lock, since we are operating on ourself.
1680 Handle threadObj(thread, oopDesc::bs()->write_barrier(thread->threadObj()));
1681 assert(threadObj.not_null(), "java thread object must exist");
1682 ObjectLocker lock(threadObj, thread);
1683 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1684 thread->clear_pending_exception();
1685 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1686 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1687 // Clear the native thread instance - this makes isAlive return false and allows the join()
1688 // to complete once we've done the notify_all below
1689 java_lang_Thread::set_thread(threadObj(), NULL);
1690 lock.notify_all(thread);
1691 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1692 thread->clear_pending_exception();
1693 }
1694
1695
1696 // For any new cleanup additions, please check to see if they need to be applied to
1697 // cleanup_failed_attach_current_thread as well.
1698 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1699 assert(this == JavaThread::current(), "thread consistency check");
1700
1701 HandleMark hm(this);
1702 Handle uncaught_exception(this, this->pending_exception());
1703 this->clear_pending_exception();
1704 Handle threadObj(this, this->threadObj());
1705 assert(threadObj.not_null(), "Java thread object should be created");
1706
1707 if (get_thread_profiler() != NULL) {
1708 get_thread_profiler()->disengage();
1709 ResourceMark rm;
1710 get_thread_profiler()->print(get_thread_name());
1711 }
1712
1713
1714 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1715 {
1716 EXCEPTION_MARK;
1717
1718 CLEAR_PENDING_EXCEPTION;
1719 }
1720 if (!destroy_vm) {
1721 if (uncaught_exception.not_null()) {
1722 EXCEPTION_MARK;
1723 // Call method Thread.dispatchUncaughtException().
1724 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1725 JavaValue result(T_VOID);
1726 JavaCalls::call_virtual(&result,
1727 threadObj, thread_klass,
1728 vmSymbols::dispatchUncaughtException_name(),
1729 vmSymbols::throwable_void_signature(),
1730 uncaught_exception,
1731 THREAD);
1732 if (HAS_PENDING_EXCEPTION) {
1733 ResourceMark rm(this);
1734 jio_fprintf(defaultStream::error_stream(),
1735 "\nException: %s thrown from the UncaughtExceptionHandler"
1736 " in thread \"%s\"\n",
1737 pending_exception()->klass()->external_name(),
1738 get_thread_name());
1739 CLEAR_PENDING_EXCEPTION;
1740 }
1741 }
1742
1743 // Called before the java thread exit since we want to read info
1744 // from java_lang_Thread object
1745 EventThreadEnd event;
1746 if (event.should_commit()) {
1747 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1748 event.commit();
1749 }
1750
1751 // Call after last event on thread
1752 EVENT_THREAD_EXIT(this);
1753
1754 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1755 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1756 // is deprecated anyhow.
1757 if (!is_Compiler_thread()) {
1758 int count = 3;
1759 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1760 EXCEPTION_MARK;
1761 JavaValue result(T_VOID);
1762 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1763 JavaCalls::call_virtual(&result,
1764 threadObj, thread_klass,
1765 vmSymbols::exit_method_name(),
1766 vmSymbols::void_method_signature(),
1767 THREAD);
1768 CLEAR_PENDING_EXCEPTION;
1769 }
1770 }
1771 // notify JVMTI
1772 if (JvmtiExport::should_post_thread_life()) {
1773 JvmtiExport::post_thread_end(this);
1774 }
1775
1776 // We have notified the agents that we are exiting, before we go on,
1777 // we must check for a pending external suspend request and honor it
1778 // in order to not surprise the thread that made the suspend request.
1779 while (true) {
1780 {
1781 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1782 if (!is_external_suspend()) {
1783 set_terminated(_thread_exiting);
1784 ThreadService::current_thread_exiting(this);
1785 break;
1786 }
1787 // Implied else:
1788 // Things get a little tricky here. We have a pending external
1789 // suspend request, but we are holding the SR_lock so we
1790 // can't just self-suspend. So we temporarily drop the lock
1791 // and then self-suspend.
1792 }
1793
1794 ThreadBlockInVM tbivm(this);
1795 java_suspend_self();
1796
1797 // We're done with this suspend request, but we have to loop around
1798 // and check again. Eventually we will get SR_lock without a pending
1799 // external suspend request and will be able to mark ourselves as
1800 // exiting.
1801 }
1802 // no more external suspends are allowed at this point
1803 } else {
1804 // before_exit() has already posted JVMTI THREAD_END events
1805 }
1806
1807 // Notify waiters on thread object. This has to be done after exit() is called
1808 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1809 // group should have the destroyed bit set before waiters are notified).
1810 ensure_join(this);
1811 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1812
1813 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1814 // held by this thread must be released. The spec does not distinguish
1815 // between JNI-acquired and regular Java monitors. We can only see
1816 // regular Java monitors here if monitor enter-exit matching is broken.
1817 //
1818 // Optionally release any monitors for regular JavaThread exits. This
1819 // is provided as a work around for any bugs in monitor enter-exit
1820 // matching. This can be expensive so it is not enabled by default.
1821 // ObjectMonitor::Knob_ExitRelease is a superset of the
1822 // JNIDetachReleasesMonitors option.
1823 //
1824 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1825 // ObjectSynchronizer::release_monitors_owned_by_thread().
1826 if ((exit_type == jni_detach && JNIDetachReleasesMonitors) ||
1827 ObjectMonitor::Knob_ExitRelease) {
1828 // Sanity check even though JNI DetachCurrentThread() would have
1829 // returned JNI_ERR if there was a Java frame. JavaThread exit
1830 // should be done executing Java code by the time we get here.
1831 assert(!this->has_last_Java_frame(),
1832 "should not have a Java frame when detaching or exiting");
1833 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1834 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1835 }
1836
1837 // These things needs to be done while we are still a Java Thread. Make sure that thread
1838 // is in a consistent state, in case GC happens
1839 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1840
1841 if (active_handles() != NULL) {
1842 JNIHandleBlock* block = active_handles();
1843 set_active_handles(NULL);
1844 JNIHandleBlock::release_block(block);
1845 }
1846
1847 if (free_handle_block() != NULL) {
1848 JNIHandleBlock* block = free_handle_block();
1849 set_free_handle_block(NULL);
1850 JNIHandleBlock::release_block(block);
1851 }
1852
1853 // These have to be removed while this is still a valid thread.
1854 remove_stack_guard_pages();
1855
1856 if (UseTLAB) {
1857 tlab().make_parsable(true); // retire TLAB
1858 }
1859
1860 if (JvmtiEnv::environments_might_exist()) {
1861 JvmtiExport::cleanup_thread(this);
1862 }
1863
1864 // We must flush any deferred card marks before removing a thread from
1865 // the list of active threads.
1866 Universe::heap()->flush_deferred_store_barrier(this);
1867 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1868
1869 #if INCLUDE_ALL_GCS
1870 // We must flush the G1-related buffers before removing a thread
1871 // from the list of active threads. We must do this after any deferred
1872 // card marks have been flushed (above) so that any entries that are
1873 // added to the thread's dirty card queue as a result are not lost.
1874 if (UseG1GC || UseShenandoahGC) {
1875 flush_barrier_queues();
1876 }
1877 if (UseShenandoahGC && UseTLAB) {
1878 gclab().make_parsable(true);
1879 }
1880 #endif // INCLUDE_ALL_GCS
1881
1882 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1883 Threads::remove(this);
1884 }
1885
1886 #if INCLUDE_ALL_GCS
1887 // Flush G1-related queues.
1888 void JavaThread::flush_barrier_queues() {
1889 satb_mark_queue().flush();
1890 dirty_card_queue().flush();
1891 }
1892
1893 void JavaThread::initialize_queues() {
1894 assert(!SafepointSynchronize::is_at_safepoint(),
1895 "we should not be at a safepoint");
1896
1897 ObjPtrQueue& satb_queue = satb_mark_queue();
1898 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1899 // The SATB queue should have been constructed with its active
1900 // field set to false.
1901 assert(!satb_queue.is_active(), "SATB queue should not be active");
1902 assert(satb_queue.is_empty(), "SATB queue should be empty");
1903 // If we are creating the thread during a marking cycle, we should
1904 // set the active field of the SATB queue to true.
1905 if (satb_queue_set.is_active()) {
1906 satb_queue.set_active(true);
1907 }
1908
1909 DirtyCardQueue& dirty_queue = dirty_card_queue();
1910 // The dirty card queue should have been constructed with its
1911 // active field set to true.
1912 assert(dirty_queue.is_active(), "dirty card queue should be active");
1913 }
1914
1915 bool JavaThread::evacuation_in_progress() const {
1916 return _evacuation_in_progress;
1917 }
1918
1919 void JavaThread::set_evacuation_in_progress(bool in_prog) {
1920 _evacuation_in_progress = in_prog;
1921 }
1922
1923 void JavaThread::set_evacuation_in_progress_all_threads(bool in_prog) {
1924 _evacuation_in_progress_global = in_prog;
1925 for (JavaThread* t = Threads::first(); t; t = t->next()) {
1926 t->set_evacuation_in_progress(in_prog);
1927 }
1928 }
1929 #endif // INCLUDE_ALL_GCS
1930
1931 void JavaThread::cleanup_failed_attach_current_thread() {
1932 if (get_thread_profiler() != NULL) {
1933 get_thread_profiler()->disengage();
1934 ResourceMark rm;
1935 get_thread_profiler()->print(get_thread_name());
1936 }
1937
1938 if (active_handles() != NULL) {
1939 JNIHandleBlock* block = active_handles();
1940 set_active_handles(NULL);
1941 JNIHandleBlock::release_block(block);
1942 }
1943
1944 if (free_handle_block() != NULL) {
1945 JNIHandleBlock* block = free_handle_block();
1946 set_free_handle_block(NULL);
1947 JNIHandleBlock::release_block(block);
1948 }
1949
1950 // These have to be removed while this is still a valid thread.
1951 remove_stack_guard_pages();
1952
1953 if (UseTLAB) {
1954 tlab().make_parsable(true); // retire TLAB, if any
1955 }
1956
1957 #if INCLUDE_ALL_GCS
1958 if (UseG1GC || UseShenandoahGC) {
1959 flush_barrier_queues();
1960 }
1961 if (UseShenandoahGC && UseTLAB) {
1962 gclab().make_parsable(true);
1963 }
1964 #endif // INCLUDE_ALL_GCS
1965
1966 Threads::remove(this);
1967 delete this;
1968 }
1969
1970
1971
1972
1973 JavaThread* JavaThread::active() {
1974 Thread* thread = ThreadLocalStorage::thread();
1975 assert(thread != NULL, "just checking");
1976 if (thread->is_Java_thread()) {
1977 return (JavaThread*) thread;
1978 } else {
1979 assert(thread->is_VM_thread(), "this must be a vm thread");
1980 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1981 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1982 assert(ret->is_Java_thread(), "must be a Java thread");
1983 return ret;
1984 }
1985 }
1986
1987 bool JavaThread::is_lock_owned(address adr) const {
1988 if (Thread::is_lock_owned(adr)) return true;
1989
1990 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1991 if (chunk->contains(adr)) return true;
1992 }
1993
1994 return false;
1995 }
1996
1997
1998 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1999 chunk->set_next(monitor_chunks());
2000 set_monitor_chunks(chunk);
2001 }
2002
2003 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2004 guarantee(monitor_chunks() != NULL, "must be non empty");
2005 if (monitor_chunks() == chunk) {
2006 set_monitor_chunks(chunk->next());
2007 } else {
2008 MonitorChunk* prev = monitor_chunks();
2009 while (prev->next() != chunk) prev = prev->next();
2010 prev->set_next(chunk->next());
2011 }
2012 }
2013
2014 // JVM support.
2015
2016 // Note: this function shouldn't block if it's called in
2017 // _thread_in_native_trans state (such as from
2018 // check_special_condition_for_native_trans()).
2019 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2020
2021 if (has_last_Java_frame() && has_async_condition()) {
2022 // If we are at a polling page safepoint (not a poll return)
2023 // then we must defer async exception because live registers
2024 // will be clobbered by the exception path. Poll return is
2025 // ok because the call we a returning from already collides
2026 // with exception handling registers and so there is no issue.
2027 // (The exception handling path kills call result registers but
2028 // this is ok since the exception kills the result anyway).
2029
2030 if (is_at_poll_safepoint()) {
2031 // if the code we are returning to has deoptimized we must defer
2032 // the exception otherwise live registers get clobbered on the
2033 // exception path before deoptimization is able to retrieve them.
2034 //
2035 RegisterMap map(this, false);
2036 frame caller_fr = last_frame().sender(&map);
2037 assert(caller_fr.is_compiled_frame(), "what?");
2038 if (caller_fr.is_deoptimized_frame()) {
2039 if (TraceExceptions) {
2040 ResourceMark rm;
2041 tty->print_cr("deferred async exception at compiled safepoint");
2042 }
2043 return;
2044 }
2045 }
2046 }
2047
2048 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2049 if (condition == _no_async_condition) {
2050 // Conditions have changed since has_special_runtime_exit_condition()
2051 // was called:
2052 // - if we were here only because of an external suspend request,
2053 // then that was taken care of above (or cancelled) so we are done
2054 // - if we were here because of another async request, then it has
2055 // been cleared between the has_special_runtime_exit_condition()
2056 // and now so again we are done
2057 return;
2058 }
2059
2060 // Check for pending async. exception
2061 if (_pending_async_exception != NULL) {
2062 // Only overwrite an already pending exception, if it is not a threadDeath.
2063 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2064
2065 // We cannot call Exceptions::_throw(...) here because we cannot block
2066 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2067
2068 if (TraceExceptions) {
2069 ResourceMark rm;
2070 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2071 if (has_last_Java_frame()) {
2072 frame f = last_frame();
2073 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2074 }
2075 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2076 }
2077 _pending_async_exception = NULL;
2078 clear_has_async_exception();
2079 }
2080 }
2081
2082 if (check_unsafe_error &&
2083 condition == _async_unsafe_access_error && !has_pending_exception()) {
2084 condition = _no_async_condition; // done
2085 switch (thread_state()) {
2086 case _thread_in_vm: {
2087 JavaThread* THREAD = this;
2088 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2089 }
2090 case _thread_in_native: {
2091 ThreadInVMfromNative tiv(this);
2092 JavaThread* THREAD = this;
2093 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2094 }
2095 case _thread_in_Java: {
2096 ThreadInVMfromJava tiv(this);
2097 JavaThread* THREAD = this;
2098 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2099 }
2100 default:
2101 ShouldNotReachHere();
2102 }
2103 }
2104
2105 assert(condition == _no_async_condition || has_pending_exception() ||
2106 (!check_unsafe_error && condition == _async_unsafe_access_error),
2107 "must have handled the async condition, if no exception");
2108 }
2109
2110 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2111 //
2112 // Check for pending external suspend. Internal suspend requests do
2113 // not use handle_special_runtime_exit_condition().
2114 // If JNIEnv proxies are allowed, don't self-suspend if the target
2115 // thread is not the current thread. In older versions of jdbx, jdbx
2116 // threads could call into the VM with another thread's JNIEnv so we
2117 // can be here operating on behalf of a suspended thread (4432884).
2118 bool do_self_suspend = is_external_suspend_with_lock();
2119 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2120 //
2121 // Because thread is external suspended the safepoint code will count
2122 // thread as at a safepoint. This can be odd because we can be here
2123 // as _thread_in_Java which would normally transition to _thread_blocked
2124 // at a safepoint. We would like to mark the thread as _thread_blocked
2125 // before calling java_suspend_self like all other callers of it but
2126 // we must then observe proper safepoint protocol. (We can't leave
2127 // _thread_blocked with a safepoint in progress). However we can be
2128 // here as _thread_in_native_trans so we can't use a normal transition
2129 // constructor/destructor pair because they assert on that type of
2130 // transition. We could do something like:
2131 //
2132 // JavaThreadState state = thread_state();
2133 // set_thread_state(_thread_in_vm);
2134 // {
2135 // ThreadBlockInVM tbivm(this);
2136 // java_suspend_self()
2137 // }
2138 // set_thread_state(_thread_in_vm_trans);
2139 // if (safepoint) block;
2140 // set_thread_state(state);
2141 //
2142 // but that is pretty messy. Instead we just go with the way the
2143 // code has worked before and note that this is the only path to
2144 // java_suspend_self that doesn't put the thread in _thread_blocked
2145 // mode.
2146
2147 frame_anchor()->make_walkable(this);
2148 java_suspend_self();
2149
2150 // We might be here for reasons in addition to the self-suspend request
2151 // so check for other async requests.
2152 }
2153
2154 if (check_asyncs) {
2155 check_and_handle_async_exceptions();
2156 }
2157 }
2158
2159 void JavaThread::send_thread_stop(oop java_throwable) {
2160 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2161 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2162 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2163
2164 // Do not throw asynchronous exceptions against the compiler thread
2165 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2166 if (is_Compiler_thread()) return;
2167
2168 {
2169 // Actually throw the Throwable against the target Thread - however
2170 // only if there is no thread death exception installed already.
2171 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2172 // If the topmost frame is a runtime stub, then we are calling into
2173 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2174 // must deoptimize the caller before continuing, as the compiled exception handler table
2175 // may not be valid
2176 if (has_last_Java_frame()) {
2177 frame f = last_frame();
2178 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2179 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2180 RegisterMap reg_map(this, UseBiasedLocking);
2181 frame compiled_frame = f.sender(®_map);
2182 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2183 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2184 }
2185 }
2186 }
2187
2188 // Set async. pending exception in thread.
2189 set_pending_async_exception(java_throwable);
2190
2191 if (TraceExceptions) {
2192 ResourceMark rm;
2193 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2194 }
2195 // for AbortVMOnException flag
2196 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2197 }
2198 }
2199
2200
2201 // Interrupt thread so it will wake up from a potential wait()
2202 Thread::interrupt(this);
2203 }
2204
2205 // External suspension mechanism.
2206 //
2207 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2208 // to any VM_locks and it is at a transition
2209 // Self-suspension will happen on the transition out of the vm.
2210 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2211 //
2212 // Guarantees on return:
2213 // + Target thread will not execute any new bytecode (that's why we need to
2214 // force a safepoint)
2215 // + Target thread will not enter any new monitors
2216 //
2217 void JavaThread::java_suspend() {
2218 { MutexLocker mu(Threads_lock);
2219 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2220 return;
2221 }
2222 }
2223
2224 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2225 if (!is_external_suspend()) {
2226 // a racing resume has cancelled us; bail out now
2227 return;
2228 }
2229
2230 // suspend is done
2231 uint32_t debug_bits = 0;
2232 // Warning: is_ext_suspend_completed() may temporarily drop the
2233 // SR_lock to allow the thread to reach a stable thread state if
2234 // it is currently in a transient thread state.
2235 if (is_ext_suspend_completed(false /* !called_by_wait */,
2236 SuspendRetryDelay, &debug_bits)) {
2237 return;
2238 }
2239 }
2240
2241 VM_ForceSafepoint vm_suspend;
2242 VMThread::execute(&vm_suspend);
2243 }
2244
2245 // Part II of external suspension.
2246 // A JavaThread self suspends when it detects a pending external suspend
2247 // request. This is usually on transitions. It is also done in places
2248 // where continuing to the next transition would surprise the caller,
2249 // e.g., monitor entry.
2250 //
2251 // Returns the number of times that the thread self-suspended.
2252 //
2253 // Note: DO NOT call java_suspend_self() when you just want to block current
2254 // thread. java_suspend_self() is the second stage of cooperative
2255 // suspension for external suspend requests and should only be used
2256 // to complete an external suspend request.
2257 //
2258 int JavaThread::java_suspend_self() {
2259 int ret = 0;
2260
2261 // we are in the process of exiting so don't suspend
2262 if (is_exiting()) {
2263 clear_external_suspend();
2264 return ret;
2265 }
2266
2267 assert(_anchor.walkable() ||
2268 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2269 "must have walkable stack");
2270
2271 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2272
2273 assert(!this->is_ext_suspended(),
2274 "a thread trying to self-suspend should not already be suspended");
2275
2276 if (this->is_suspend_equivalent()) {
2277 // If we are self-suspending as a result of the lifting of a
2278 // suspend equivalent condition, then the suspend_equivalent
2279 // flag is not cleared until we set the ext_suspended flag so
2280 // that wait_for_ext_suspend_completion() returns consistent
2281 // results.
2282 this->clear_suspend_equivalent();
2283 }
2284
2285 // A racing resume may have cancelled us before we grabbed SR_lock
2286 // above. Or another external suspend request could be waiting for us
2287 // by the time we return from SR_lock()->wait(). The thread
2288 // that requested the suspension may already be trying to walk our
2289 // stack and if we return now, we can change the stack out from under
2290 // it. This would be a "bad thing (TM)" and cause the stack walker
2291 // to crash. We stay self-suspended until there are no more pending
2292 // external suspend requests.
2293 while (is_external_suspend()) {
2294 ret++;
2295 this->set_ext_suspended();
2296
2297 // _ext_suspended flag is cleared by java_resume()
2298 while (is_ext_suspended()) {
2299 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2300 }
2301 }
2302
2303 return ret;
2304 }
2305
2306 #ifdef ASSERT
2307 // verify the JavaThread has not yet been published in the Threads::list, and
2308 // hence doesn't need protection from concurrent access at this stage
2309 void JavaThread::verify_not_published() {
2310 if (!Threads_lock->owned_by_self()) {
2311 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2312 assert(!Threads::includes(this),
2313 "java thread shouldn't have been published yet!");
2314 } else {
2315 assert(!Threads::includes(this),
2316 "java thread shouldn't have been published yet!");
2317 }
2318 }
2319 #endif
2320
2321 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2322 // progress or when _suspend_flags is non-zero.
2323 // Current thread needs to self-suspend if there is a suspend request and/or
2324 // block if a safepoint is in progress.
2325 // Async exception ISN'T checked.
2326 // Note only the ThreadInVMfromNative transition can call this function
2327 // directly and when thread state is _thread_in_native_trans
2328 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2329 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2330
2331 JavaThread *curJT = JavaThread::current();
2332 bool do_self_suspend = thread->is_external_suspend();
2333
2334 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2335
2336 // If JNIEnv proxies are allowed, don't self-suspend if the target
2337 // thread is not the current thread. In older versions of jdbx, jdbx
2338 // threads could call into the VM with another thread's JNIEnv so we
2339 // can be here operating on behalf of a suspended thread (4432884).
2340 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2341 JavaThreadState state = thread->thread_state();
2342
2343 // We mark this thread_blocked state as a suspend-equivalent so
2344 // that a caller to is_ext_suspend_completed() won't be confused.
2345 // The suspend-equivalent state is cleared by java_suspend_self().
2346 thread->set_suspend_equivalent();
2347
2348 // If the safepoint code sees the _thread_in_native_trans state, it will
2349 // wait until the thread changes to other thread state. There is no
2350 // guarantee on how soon we can obtain the SR_lock and complete the
2351 // self-suspend request. It would be a bad idea to let safepoint wait for
2352 // too long. Temporarily change the state to _thread_blocked to
2353 // let the VM thread know that this thread is ready for GC. The problem
2354 // of changing thread state is that safepoint could happen just after
2355 // java_suspend_self() returns after being resumed, and VM thread will
2356 // see the _thread_blocked state. We must check for safepoint
2357 // after restoring the state and make sure we won't leave while a safepoint
2358 // is in progress.
2359 thread->set_thread_state(_thread_blocked);
2360 thread->java_suspend_self();
2361 thread->set_thread_state(state);
2362 // Make sure new state is seen by VM thread
2363 if (os::is_MP()) {
2364 if (UseMembar) {
2365 // Force a fence between the write above and read below
2366 OrderAccess::fence();
2367 } else {
2368 // Must use this rather than serialization page in particular on Windows
2369 InterfaceSupport::serialize_memory(thread);
2370 }
2371 }
2372 }
2373
2374 if (SafepointSynchronize::do_call_back()) {
2375 // If we are safepointing, then block the caller which may not be
2376 // the same as the target thread (see above).
2377 SafepointSynchronize::block(curJT);
2378 }
2379
2380 if (thread->is_deopt_suspend()) {
2381 thread->clear_deopt_suspend();
2382 RegisterMap map(thread, false);
2383 frame f = thread->last_frame();
2384 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2385 f = f.sender(&map);
2386 }
2387 if (f.id() == thread->must_deopt_id()) {
2388 thread->clear_must_deopt_id();
2389 f.deoptimize(thread);
2390 } else {
2391 fatal("missed deoptimization!");
2392 }
2393 }
2394 }
2395
2396 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2397 // progress or when _suspend_flags is non-zero.
2398 // Current thread needs to self-suspend if there is a suspend request and/or
2399 // block if a safepoint is in progress.
2400 // Also check for pending async exception (not including unsafe access error).
2401 // Note only the native==>VM/Java barriers can call this function and when
2402 // thread state is _thread_in_native_trans.
2403 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2404 check_safepoint_and_suspend_for_native_trans(thread);
2405
2406 if (thread->has_async_exception()) {
2407 // We are in _thread_in_native_trans state, don't handle unsafe
2408 // access error since that may block.
2409 thread->check_and_handle_async_exceptions(false);
2410 }
2411 }
2412
2413 // This is a variant of the normal
2414 // check_special_condition_for_native_trans with slightly different
2415 // semantics for use by critical native wrappers. It does all the
2416 // normal checks but also performs the transition back into
2417 // thread_in_Java state. This is required so that critical natives
2418 // can potentially block and perform a GC if they are the last thread
2419 // exiting the GC_locker.
2420 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2421 check_special_condition_for_native_trans(thread);
2422
2423 // Finish the transition
2424 thread->set_thread_state(_thread_in_Java);
2425
2426 if (thread->do_critical_native_unlock()) {
2427 ThreadInVMfromJavaNoAsyncException tiv(thread);
2428 GC_locker::unlock_critical(thread);
2429 thread->clear_critical_native_unlock();
2430 }
2431 }
2432
2433 // We need to guarantee the Threads_lock here, since resumes are not
2434 // allowed during safepoint synchronization
2435 // Can only resume from an external suspension
2436 void JavaThread::java_resume() {
2437 assert_locked_or_safepoint(Threads_lock);
2438
2439 // Sanity check: thread is gone, has started exiting or the thread
2440 // was not externally suspended.
2441 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2442 return;
2443 }
2444
2445 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2446
2447 clear_external_suspend();
2448
2449 if (is_ext_suspended()) {
2450 clear_ext_suspended();
2451 SR_lock()->notify_all();
2452 }
2453 }
2454
2455 void JavaThread::create_stack_guard_pages() {
2456 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2457 address low_addr = stack_base() - stack_size();
2458 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2459
2460 int allocate = os::allocate_stack_guard_pages();
2461 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2462
2463 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2464 warning("Attempt to allocate stack guard pages failed.");
2465 return;
2466 }
2467
2468 if (os::guard_memory((char *) low_addr, len)) {
2469 _stack_guard_state = stack_guard_enabled;
2470 } else {
2471 warning("Attempt to protect stack guard pages failed.");
2472 if (os::uncommit_memory((char *) low_addr, len)) {
2473 warning("Attempt to deallocate stack guard pages failed.");
2474 }
2475 }
2476 }
2477
2478 void JavaThread::remove_stack_guard_pages() {
2479 assert(Thread::current() == this, "from different thread");
2480 if (_stack_guard_state == stack_guard_unused) return;
2481 address low_addr = stack_base() - stack_size();
2482 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2483
2484 if (os::allocate_stack_guard_pages()) {
2485 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2486 _stack_guard_state = stack_guard_unused;
2487 } else {
2488 warning("Attempt to deallocate stack guard pages failed.");
2489 }
2490 } else {
2491 if (_stack_guard_state == stack_guard_unused) return;
2492 if (os::unguard_memory((char *) low_addr, len)) {
2493 _stack_guard_state = stack_guard_unused;
2494 } else {
2495 warning("Attempt to unprotect stack guard pages failed.");
2496 }
2497 }
2498 }
2499
2500 void JavaThread::enable_stack_yellow_zone() {
2501 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2502 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2503
2504 // The base notation is from the stacks point of view, growing downward.
2505 // We need to adjust it to work correctly with guard_memory()
2506 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2507
2508 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2509 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2510
2511 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2512 _stack_guard_state = stack_guard_enabled;
2513 } else {
2514 warning("Attempt to guard stack yellow zone failed.");
2515 }
2516 enable_register_stack_guard();
2517 }
2518
2519 void JavaThread::disable_stack_yellow_zone() {
2520 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2521 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2522
2523 // Simply return if called for a thread that does not use guard pages.
2524 if (_stack_guard_state == stack_guard_unused) return;
2525
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 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2529
2530 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2531 _stack_guard_state = stack_guard_yellow_disabled;
2532 } else {
2533 warning("Attempt to unguard stack yellow zone failed.");
2534 }
2535 disable_register_stack_guard();
2536 }
2537
2538 void JavaThread::enable_stack_red_zone() {
2539 // The base notation is from the stacks point of view, growing downward.
2540 // We need to adjust it to work correctly with guard_memory()
2541 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2542 address base = stack_red_zone_base() - stack_red_zone_size();
2543
2544 guarantee(base < stack_base(), "Error calculating stack red zone");
2545 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2546
2547 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2548 warning("Attempt to guard stack red zone failed.");
2549 }
2550 }
2551
2552 void JavaThread::disable_stack_red_zone() {
2553 // The base notation is from the stacks point of view, growing downward.
2554 // We need to adjust it to work correctly with guard_memory()
2555 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2556 address base = stack_red_zone_base() - stack_red_zone_size();
2557 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2558 warning("Attempt to unguard stack red zone failed.");
2559 }
2560 }
2561
2562 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2563 // ignore is there is no stack
2564 if (!has_last_Java_frame()) return;
2565 // traverse the stack frames. Starts from top frame.
2566 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2567 frame* fr = fst.current();
2568 f(fr, fst.register_map());
2569 }
2570 }
2571
2572
2573 #ifndef PRODUCT
2574 // Deoptimization
2575 // Function for testing deoptimization
2576 void JavaThread::deoptimize() {
2577 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2578 StackFrameStream fst(this, UseBiasedLocking);
2579 bool deopt = false; // Dump stack only if a deopt actually happens.
2580 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2581 // Iterate over all frames in the thread and deoptimize
2582 for (; !fst.is_done(); fst.next()) {
2583 if (fst.current()->can_be_deoptimized()) {
2584
2585 if (only_at) {
2586 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2587 // consists of comma or carriage return separated numbers so
2588 // search for the current bci in that string.
2589 address pc = fst.current()->pc();
2590 nmethod* nm = (nmethod*) fst.current()->cb();
2591 ScopeDesc* sd = nm->scope_desc_at(pc);
2592 char buffer[8];
2593 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2594 size_t len = strlen(buffer);
2595 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2596 while (found != NULL) {
2597 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2598 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2599 // Check that the bci found is bracketed by terminators.
2600 break;
2601 }
2602 found = strstr(found + 1, buffer);
2603 }
2604 if (!found) {
2605 continue;
2606 }
2607 }
2608
2609 if (DebugDeoptimization && !deopt) {
2610 deopt = true; // One-time only print before deopt
2611 tty->print_cr("[BEFORE Deoptimization]");
2612 trace_frames();
2613 trace_stack();
2614 }
2615 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2616 }
2617 }
2618
2619 if (DebugDeoptimization && deopt) {
2620 tty->print_cr("[AFTER Deoptimization]");
2621 trace_frames();
2622 }
2623 }
2624
2625
2626 // Make zombies
2627 void JavaThread::make_zombies() {
2628 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2629 if (fst.current()->can_be_deoptimized()) {
2630 // it is a Java nmethod
2631 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2632 nm->make_not_entrant();
2633 }
2634 }
2635 }
2636 #endif // PRODUCT
2637
2638
2639 void JavaThread::deoptimized_wrt_marked_nmethods() {
2640 if (!has_last_Java_frame()) return;
2641 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2642 StackFrameStream fst(this, UseBiasedLocking);
2643 for (; !fst.is_done(); fst.next()) {
2644 if (fst.current()->should_be_deoptimized()) {
2645 if (LogCompilation && xtty != NULL) {
2646 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2647 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2648 this->name(), nm != NULL ? nm->compile_id() : -1);
2649 }
2650
2651 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2652 }
2653 }
2654 }
2655
2656
2657 // If the caller is a NamedThread, then remember, in the current scope,
2658 // the given JavaThread in its _processed_thread field.
2659 class RememberProcessedThread: public StackObj {
2660 NamedThread* _cur_thr;
2661 public:
2662 RememberProcessedThread(JavaThread* jthr) {
2663 Thread* thread = Thread::current();
2664 if (thread->is_Named_thread()) {
2665 _cur_thr = (NamedThread *)thread;
2666 _cur_thr->set_processed_thread(jthr);
2667 } else {
2668 _cur_thr = NULL;
2669 }
2670 }
2671
2672 ~RememberProcessedThread() {
2673 if (_cur_thr) {
2674 _cur_thr->set_processed_thread(NULL);
2675 }
2676 }
2677 };
2678
2679 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2680 // Verify that the deferred card marks have been flushed.
2681 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2682
2683 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2684 // since there may be more than one thread using each ThreadProfiler.
2685
2686 // Traverse the GCHandles
2687 Thread::oops_do(f, cld_f, cf);
2688
2689 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2690 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2691
2692 if (has_last_Java_frame()) {
2693 // Record JavaThread to GC thread
2694 RememberProcessedThread rpt(this);
2695
2696 // Traverse the privileged stack
2697 if (_privileged_stack_top != NULL) {
2698 _privileged_stack_top->oops_do(f);
2699 }
2700
2701 // traverse the registered growable array
2702 if (_array_for_gc != NULL) {
2703 for (int index = 0; index < _array_for_gc->length(); index++) {
2704 f->do_oop(_array_for_gc->adr_at(index));
2705 }
2706 }
2707
2708 // Traverse the monitor chunks
2709 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2710 chunk->oops_do(f);
2711 }
2712
2713 // Traverse the execution stack
2714 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2715 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2716 }
2717 }
2718
2719 // callee_target is never live across a gc point so NULL it here should
2720 // it still contain a methdOop.
2721
2722 set_callee_target(NULL);
2723
2724 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2725 // If we have deferred set_locals there might be oops waiting to be
2726 // written
2727 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2728 if (list != NULL) {
2729 for (int i = 0; i < list->length(); i++) {
2730 list->at(i)->oops_do(f);
2731 }
2732 }
2733
2734 // Traverse instance variables at the end since the GC may be moving things
2735 // around using this function
2736 f->do_oop((oop*) &_threadObj);
2737 f->do_oop((oop*) &_vm_result);
2738 f->do_oop((oop*) &_exception_oop);
2739 f->do_oop((oop*) &_pending_async_exception);
2740
2741 if (jvmti_thread_state() != NULL) {
2742 jvmti_thread_state()->oops_do(f);
2743 }
2744 }
2745
2746 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2747 Thread::nmethods_do(cf); // (super method is a no-op)
2748
2749 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2750 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2751
2752 if (has_last_Java_frame()) {
2753 // Traverse the execution stack
2754 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2755 fst.current()->nmethods_do(cf);
2756 }
2757 }
2758 }
2759
2760 void JavaThread::metadata_do(void f(Metadata*)) {
2761 if (has_last_Java_frame()) {
2762 // Traverse the execution stack to call f() on the methods in the stack
2763 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2764 fst.current()->metadata_do(f);
2765 }
2766 } else if (is_Compiler_thread()) {
2767 // need to walk ciMetadata in current compile tasks to keep alive.
2768 CompilerThread* ct = (CompilerThread*)this;
2769 if (ct->env() != NULL) {
2770 ct->env()->metadata_do(f);
2771 }
2772 if (ct->task() != NULL) {
2773 ct->task()->metadata_do(f);
2774 }
2775 }
2776 }
2777
2778 // Printing
2779 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2780 switch (_thread_state) {
2781 case _thread_uninitialized: return "_thread_uninitialized";
2782 case _thread_new: return "_thread_new";
2783 case _thread_new_trans: return "_thread_new_trans";
2784 case _thread_in_native: return "_thread_in_native";
2785 case _thread_in_native_trans: return "_thread_in_native_trans";
2786 case _thread_in_vm: return "_thread_in_vm";
2787 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2788 case _thread_in_Java: return "_thread_in_Java";
2789 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2790 case _thread_blocked: return "_thread_blocked";
2791 case _thread_blocked_trans: return "_thread_blocked_trans";
2792 default: return "unknown thread state";
2793 }
2794 }
2795
2796 #ifndef PRODUCT
2797 void JavaThread::print_thread_state_on(outputStream *st) const {
2798 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2799 };
2800 void JavaThread::print_thread_state() const {
2801 print_thread_state_on(tty);
2802 }
2803 #endif // PRODUCT
2804
2805 // Called by Threads::print() for VM_PrintThreads operation
2806 void JavaThread::print_on(outputStream *st) const {
2807 st->print("\"%s\" ", get_thread_name());
2808 oop thread_oop = threadObj();
2809 if (thread_oop != NULL) {
2810 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2811 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2812 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2813 }
2814 Thread::print_on(st);
2815 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2816 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2817 if (thread_oop != NULL) {
2818 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2819 }
2820 #ifndef PRODUCT
2821 print_thread_state_on(st);
2822 _safepoint_state->print_on(st);
2823 #endif // PRODUCT
2824 }
2825
2826 // Called by fatal error handler. The difference between this and
2827 // JavaThread::print() is that we can't grab lock or allocate memory.
2828 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2829 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2830 oop thread_obj = threadObj();
2831 if (thread_obj != NULL) {
2832 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2833 }
2834 st->print(" [");
2835 st->print("%s", _get_thread_state_name(_thread_state));
2836 if (osthread()) {
2837 st->print(", id=%d", osthread()->thread_id());
2838 }
2839 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2840 _stack_base - _stack_size, _stack_base);
2841 st->print("]");
2842 return;
2843 }
2844
2845 // Verification
2846
2847 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2848
2849 void JavaThread::verify() {
2850 // Verify oops in the thread.
2851 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2852
2853 // Verify the stack frames.
2854 frames_do(frame_verify);
2855 }
2856
2857 // CR 6300358 (sub-CR 2137150)
2858 // Most callers of this method assume that it can't return NULL but a
2859 // thread may not have a name whilst it is in the process of attaching to
2860 // the VM - see CR 6412693, and there are places where a JavaThread can be
2861 // seen prior to having it's threadObj set (eg JNI attaching threads and
2862 // if vm exit occurs during initialization). These cases can all be accounted
2863 // for such that this method never returns NULL.
2864 const char* JavaThread::get_thread_name() const {
2865 #ifdef ASSERT
2866 // early safepoints can hit while current thread does not yet have TLS
2867 if (!SafepointSynchronize::is_at_safepoint()) {
2868 Thread *cur = Thread::current();
2869 if (!(cur->is_Java_thread() && cur == this)) {
2870 // Current JavaThreads are allowed to get their own name without
2871 // the Threads_lock.
2872 assert_locked_or_safepoint(Threads_lock);
2873 }
2874 }
2875 #endif // ASSERT
2876 return get_thread_name_string();
2877 }
2878
2879 // Returns a non-NULL representation of this thread's name, or a suitable
2880 // descriptive string if there is no set name
2881 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2882 const char* name_str;
2883 oop thread_obj = threadObj();
2884 if (thread_obj != NULL) {
2885 oop name = java_lang_Thread::name(thread_obj);
2886 if (name != NULL) {
2887 if (buf == NULL) {
2888 name_str = java_lang_String::as_utf8_string(name);
2889 } else {
2890 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2891 }
2892 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2893 name_str = "<no-name - thread is attaching>";
2894 } else {
2895 name_str = Thread::name();
2896 }
2897 } else {
2898 name_str = Thread::name();
2899 }
2900 assert(name_str != NULL, "unexpected NULL thread name");
2901 return name_str;
2902 }
2903
2904
2905 const char* JavaThread::get_threadgroup_name() const {
2906 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2907 oop thread_obj = threadObj();
2908 if (thread_obj != NULL) {
2909 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2910 if (thread_group != NULL) {
2911 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2912 name = typeArrayOop(oopDesc::bs()->read_barrier(name));
2913 // ThreadGroup.name can be null
2914 if (name != NULL) {
2915 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2916 return str;
2917 }
2918 }
2919 }
2920 return NULL;
2921 }
2922
2923 const char* JavaThread::get_parent_name() const {
2924 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2925 oop thread_obj = threadObj();
2926 if (thread_obj != NULL) {
2927 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2928 if (thread_group != NULL) {
2929 oop parent = java_lang_ThreadGroup::parent(thread_group);
2930 if (parent != NULL) {
2931 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2932 name = typeArrayOop(oopDesc::bs()->read_barrier(name));
2933 // ThreadGroup.name can be null
2934 if (name != NULL) {
2935 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2936 return str;
2937 }
2938 }
2939 }
2940 }
2941 return NULL;
2942 }
2943
2944 ThreadPriority JavaThread::java_priority() const {
2945 oop thr_oop = threadObj();
2946 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2947 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2948 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2949 return priority;
2950 }
2951
2952 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2953
2954 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2955 // Link Java Thread object <-> C++ Thread
2956
2957 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2958 // and put it into a new Handle. The Handle "thread_oop" can then
2959 // be used to pass the C++ thread object to other methods.
2960
2961 // Set the Java level thread object (jthread) field of the
2962 // new thread (a JavaThread *) to C++ thread object using the
2963 // "thread_oop" handle.
2964
2965 // Set the thread field (a JavaThread *) of the
2966 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2967
2968 Handle thread_oop(Thread::current(),
2969 JNIHandles::resolve_non_null(jni_thread));
2970 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2971 "must be initialized");
2972 set_threadObj(thread_oop());
2973 java_lang_Thread::set_thread(thread_oop(), this);
2974
2975 if (prio == NoPriority) {
2976 prio = java_lang_Thread::priority(thread_oop());
2977 assert(prio != NoPriority, "A valid priority should be present");
2978 }
2979
2980 // Push the Java priority down to the native thread; needs Threads_lock
2981 Thread::set_priority(this, prio);
2982
2983 prepare_ext();
2984
2985 // Add the new thread to the Threads list and set it in motion.
2986 // We must have threads lock in order to call Threads::add.
2987 // It is crucial that we do not block before the thread is
2988 // added to the Threads list for if a GC happens, then the java_thread oop
2989 // will not be visited by GC.
2990 Threads::add(this);
2991 }
2992
2993 oop JavaThread::current_park_blocker() {
2994 // Support for JSR-166 locks
2995 oop thread_oop = threadObj();
2996 if (thread_oop != NULL &&
2997 JDK_Version::current().supports_thread_park_blocker()) {
2998 return java_lang_Thread::park_blocker(thread_oop);
2999 }
3000 return NULL;
3001 }
3002
3003
3004 void JavaThread::print_stack_on(outputStream* st) {
3005 if (!has_last_Java_frame()) return;
3006 ResourceMark rm;
3007 HandleMark hm;
3008
3009 RegisterMap reg_map(this);
3010 vframe* start_vf = last_java_vframe(®_map);
3011 int count = 0;
3012 for (vframe* f = start_vf; f; f = f->sender()) {
3013 if (f->is_java_frame()) {
3014 javaVFrame* jvf = javaVFrame::cast(f);
3015 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3016
3017 // Print out lock information
3018 if (JavaMonitorsInStackTrace) {
3019 jvf->print_lock_info_on(st, count);
3020 }
3021 } else {
3022 // Ignore non-Java frames
3023 }
3024
3025 // Bail-out case for too deep stacks
3026 count++;
3027 if (MaxJavaStackTraceDepth == count) return;
3028 }
3029 }
3030
3031
3032 // JVMTI PopFrame support
3033 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3034 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3035 if (in_bytes(size_in_bytes) != 0) {
3036 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3037 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3038 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3039 }
3040 }
3041
3042 void* JavaThread::popframe_preserved_args() {
3043 return _popframe_preserved_args;
3044 }
3045
3046 ByteSize JavaThread::popframe_preserved_args_size() {
3047 return in_ByteSize(_popframe_preserved_args_size);
3048 }
3049
3050 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3051 int sz = in_bytes(popframe_preserved_args_size());
3052 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3053 return in_WordSize(sz / wordSize);
3054 }
3055
3056 void JavaThread::popframe_free_preserved_args() {
3057 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3058 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3059 _popframe_preserved_args = NULL;
3060 _popframe_preserved_args_size = 0;
3061 }
3062
3063 #ifndef PRODUCT
3064
3065 void JavaThread::trace_frames() {
3066 tty->print_cr("[Describe stack]");
3067 int frame_no = 1;
3068 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3069 tty->print(" %d. ", frame_no++);
3070 fst.current()->print_value_on(tty, this);
3071 tty->cr();
3072 }
3073 }
3074
3075 class PrintAndVerifyOopClosure: public OopClosure {
3076 protected:
3077 template <class T> inline void do_oop_work(T* p) {
3078 oop obj = oopDesc::load_decode_heap_oop(p);
3079 if (obj == NULL) return;
3080 tty->print(INTPTR_FORMAT ": ", p);
3081 if (obj->is_oop_or_null()) {
3082 if (obj->is_objArray()) {
3083 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3084 } else {
3085 obj->print();
3086 }
3087 } else {
3088 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3089 }
3090 tty->cr();
3091 }
3092 public:
3093 virtual void do_oop(oop* p) { do_oop_work(p); }
3094 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3095 };
3096
3097
3098 static void oops_print(frame* f, const RegisterMap *map) {
3099 PrintAndVerifyOopClosure print;
3100 f->print_value();
3101 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3102 }
3103
3104 // Print our all the locations that contain oops and whether they are
3105 // valid or not. This useful when trying to find the oldest frame
3106 // where an oop has gone bad since the frame walk is from youngest to
3107 // oldest.
3108 void JavaThread::trace_oops() {
3109 tty->print_cr("[Trace oops]");
3110 frames_do(oops_print);
3111 }
3112
3113
3114 #ifdef ASSERT
3115 // Print or validate the layout of stack frames
3116 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3117 ResourceMark rm;
3118 PRESERVE_EXCEPTION_MARK;
3119 FrameValues values;
3120 int frame_no = 0;
3121 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3122 fst.current()->describe(values, ++frame_no);
3123 if (depth == frame_no) break;
3124 }
3125 if (validate_only) {
3126 values.validate();
3127 } else {
3128 tty->print_cr("[Describe stack layout]");
3129 values.print(this);
3130 }
3131 }
3132 #endif
3133
3134 void JavaThread::trace_stack_from(vframe* start_vf) {
3135 ResourceMark rm;
3136 int vframe_no = 1;
3137 for (vframe* f = start_vf; f; f = f->sender()) {
3138 if (f->is_java_frame()) {
3139 javaVFrame::cast(f)->print_activation(vframe_no++);
3140 } else {
3141 f->print();
3142 }
3143 if (vframe_no > StackPrintLimit) {
3144 tty->print_cr("...<more frames>...");
3145 return;
3146 }
3147 }
3148 }
3149
3150
3151 void JavaThread::trace_stack() {
3152 if (!has_last_Java_frame()) return;
3153 ResourceMark rm;
3154 HandleMark hm;
3155 RegisterMap reg_map(this);
3156 trace_stack_from(last_java_vframe(®_map));
3157 }
3158
3159
3160 #endif // PRODUCT
3161
3162
3163 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3164 assert(reg_map != NULL, "a map must be given");
3165 frame f = last_frame();
3166 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3167 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3168 }
3169 return NULL;
3170 }
3171
3172
3173 Klass* JavaThread::security_get_caller_class(int depth) {
3174 vframeStream vfst(this);
3175 vfst.security_get_caller_frame(depth);
3176 if (!vfst.at_end()) {
3177 return vfst.method()->method_holder();
3178 }
3179 return NULL;
3180 }
3181
3182 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3183 assert(thread->is_Compiler_thread(), "must be compiler thread");
3184 CompileBroker::compiler_thread_loop();
3185 }
3186
3187 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3188 NMethodSweeper::sweeper_loop();
3189 }
3190
3191 // Create a CompilerThread
3192 CompilerThread::CompilerThread(CompileQueue* queue,
3193 CompilerCounters* counters)
3194 : JavaThread(&compiler_thread_entry) {
3195 _env = NULL;
3196 _log = NULL;
3197 _task = NULL;
3198 _queue = queue;
3199 _counters = counters;
3200 _buffer_blob = NULL;
3201 _compiler = NULL;
3202
3203 #ifndef PRODUCT
3204 _ideal_graph_printer = NULL;
3205 #endif
3206 }
3207
3208 // Create sweeper thread
3209 CodeCacheSweeperThread::CodeCacheSweeperThread()
3210 : JavaThread(&sweeper_thread_entry) {
3211 _scanned_nmethod = NULL;
3212 }
3213 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3214 JavaThread::oops_do(f, cld_f, cf);
3215 if (_scanned_nmethod != NULL && cf != NULL) {
3216 // Safepoints can occur when the sweeper is scanning an nmethod so
3217 // process it here to make sure it isn't unloaded in the middle of
3218 // a scan.
3219 cf->do_code_blob(_scanned_nmethod);
3220 }
3221 }
3222
3223
3224 // ======= Threads ========
3225
3226 // The Threads class links together all active threads, and provides
3227 // operations over all threads. It is protected by its own Mutex
3228 // lock, which is also used in other contexts to protect thread
3229 // operations from having the thread being operated on from exiting
3230 // and going away unexpectedly (e.g., safepoint synchronization)
3231
3232 JavaThread* Threads::_thread_list = NULL;
3233 int Threads::_number_of_threads = 0;
3234 int Threads::_number_of_non_daemon_threads = 0;
3235 int Threads::_return_code = 0;
3236 int Threads::_thread_claim_parity = 0;
3237 size_t JavaThread::_stack_size_at_create = 0;
3238 #ifdef ASSERT
3239 bool Threads::_vm_complete = false;
3240 #endif
3241
3242 // All JavaThreads
3243 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3244
3245 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3246 void Threads::threads_do(ThreadClosure* tc) {
3247 assert_locked_or_safepoint(Threads_lock);
3248 // ALL_JAVA_THREADS iterates through all JavaThreads
3249 ALL_JAVA_THREADS(p) {
3250 tc->do_thread(p);
3251 }
3252 // Someday we could have a table or list of all non-JavaThreads.
3253 // For now, just manually iterate through them.
3254 tc->do_thread(VMThread::vm_thread());
3255 Universe::heap()->gc_threads_do(tc);
3256 WatcherThread *wt = WatcherThread::watcher_thread();
3257 // Strictly speaking, the following NULL check isn't sufficient to make sure
3258 // the data for WatcherThread is still valid upon being examined. However,
3259 // considering that WatchThread terminates when the VM is on the way to
3260 // exit at safepoint, the chance of the above is extremely small. The right
3261 // way to prevent termination of WatcherThread would be to acquire
3262 // Terminator_lock, but we can't do that without violating the lock rank
3263 // checking in some cases.
3264 if (wt != NULL) {
3265 tc->do_thread(wt);
3266 }
3267
3268 // If CompilerThreads ever become non-JavaThreads, add them here
3269 }
3270
3271 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3272 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3273
3274 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3275 create_vm_init_libraries();
3276 }
3277
3278 initialize_class(vmSymbols::java_lang_String(), CHECK);
3279
3280 // Initialize java_lang.System (needed before creating the thread)
3281 initialize_class(vmSymbols::java_lang_System(), CHECK);
3282 // The VM creates & returns objects of this class. Make sure it's initialized.
3283 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3284 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3285 Handle thread_group = create_initial_thread_group(CHECK);
3286 Universe::set_main_thread_group(thread_group());
3287 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3288 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3289 main_thread->set_threadObj(thread_object);
3290 // Set thread status to running since main thread has
3291 // been started and running.
3292 java_lang_Thread::set_thread_status(thread_object,
3293 java_lang_Thread::RUNNABLE);
3294
3295 // The VM preresolves methods to these classes. Make sure that they get initialized
3296 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3297 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3298 call_initializeSystemClass(CHECK);
3299
3300 // get the Java runtime name after java.lang.System is initialized
3301 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3302 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3303
3304 // an instance of OutOfMemory exception has been allocated earlier
3305 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3306 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3307 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3308 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3309 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3310 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3311 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3312 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3313 }
3314
3315 void Threads::initialize_jsr292_core_classes(TRAPS) {
3316 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3317 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3318 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3319 }
3320
3321 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3322 extern void JDK_Version_init();
3323
3324 // Preinitialize version info.
3325 VM_Version::early_initialize();
3326
3327 // Check version
3328 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3329
3330 // Initialize the output stream module
3331 ostream_init();
3332
3333 // Process java launcher properties.
3334 Arguments::process_sun_java_launcher_properties(args);
3335
3336 // Initialize the os module before using TLS
3337 os::init();
3338
3339 // Initialize system properties.
3340 Arguments::init_system_properties();
3341
3342 // So that JDK version can be used as a discriminator when parsing arguments
3343 JDK_Version_init();
3344
3345 // Update/Initialize System properties after JDK version number is known
3346 Arguments::init_version_specific_system_properties();
3347
3348 // Parse arguments
3349 jint parse_result = Arguments::parse(args);
3350 if (parse_result != JNI_OK) return parse_result;
3351
3352 os::init_before_ergo();
3353
3354 jint ergo_result = Arguments::apply_ergo();
3355 if (ergo_result != JNI_OK) return ergo_result;
3356
3357 // Final check of all ranges after ergonomics which may change values.
3358 if (!CommandLineFlagRangeList::check_ranges()) {
3359 return JNI_EINVAL;
3360 }
3361
3362 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3363 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3364 if (!constraint_result) {
3365 return JNI_EINVAL;
3366 }
3367
3368 if (PauseAtStartup) {
3369 os::pause();
3370 }
3371
3372 HOTSPOT_VM_INIT_BEGIN();
3373
3374 // Record VM creation timing statistics
3375 TraceVmCreationTime create_vm_timer;
3376 create_vm_timer.start();
3377
3378 // Timing (must come after argument parsing)
3379 TraceTime timer("Create VM", TraceStartupTime);
3380
3381 // Initialize the os module after parsing the args
3382 jint os_init_2_result = os::init_2();
3383 if (os_init_2_result != JNI_OK) return os_init_2_result;
3384
3385 jint adjust_after_os_result = Arguments::adjust_after_os();
3386 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3387
3388 // initialize TLS
3389 ThreadLocalStorage::init();
3390
3391 // Initialize output stream logging
3392 ostream_init_log();
3393
3394 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3395 // Must be before create_vm_init_agents()
3396 if (Arguments::init_libraries_at_startup()) {
3397 convert_vm_init_libraries_to_agents();
3398 }
3399
3400 // Launch -agentlib/-agentpath and converted -Xrun agents
3401 if (Arguments::init_agents_at_startup()) {
3402 create_vm_init_agents();
3403 }
3404
3405 // Initialize Threads state
3406 _thread_list = NULL;
3407 _number_of_threads = 0;
3408 _number_of_non_daemon_threads = 0;
3409
3410 // Initialize global data structures and create system classes in heap
3411 vm_init_globals();
3412
3413 // Attach the main thread to this os thread
3414 JavaThread* main_thread = new JavaThread();
3415 main_thread->set_thread_state(_thread_in_vm);
3416 // must do this before set_active_handles and initialize_thread_local_storage
3417 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3418 // change the stack size recorded here to one based on the java thread
3419 // stacksize. This adjusted size is what is used to figure the placement
3420 // of the guard pages.
3421 main_thread->record_stack_base_and_size();
3422 main_thread->initialize_thread_local_storage();
3423
3424 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3425
3426 if (!main_thread->set_as_starting_thread()) {
3427 vm_shutdown_during_initialization(
3428 "Failed necessary internal allocation. Out of swap space");
3429 delete main_thread;
3430 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3431 return JNI_ENOMEM;
3432 }
3433
3434 // Enable guard page *after* os::create_main_thread(), otherwise it would
3435 // crash Linux VM, see notes in os_linux.cpp.
3436 main_thread->create_stack_guard_pages();
3437
3438 // Initialize Java-Level synchronization subsystem
3439 ObjectMonitor::Initialize();
3440
3441 // Initialize global modules
3442 jint status = init_globals();
3443 if (status != JNI_OK) {
3444 delete main_thread;
3445 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3446 return status;
3447 }
3448
3449 // Should be done after the heap is fully created
3450 main_thread->cache_global_variables();
3451
3452 HandleMark hm;
3453
3454 { MutexLocker mu(Threads_lock);
3455 Threads::add(main_thread);
3456 }
3457
3458 // Any JVMTI raw monitors entered in onload will transition into
3459 // real raw monitor. VM is setup enough here for raw monitor enter.
3460 JvmtiExport::transition_pending_onload_raw_monitors();
3461
3462 // Create the VMThread
3463 { TraceTime timer("Start VMThread", TraceStartupTime);
3464 VMThread::create();
3465 Thread* vmthread = VMThread::vm_thread();
3466
3467 if (!os::create_thread(vmthread, os::vm_thread)) {
3468 vm_exit_during_initialization("Cannot create VM thread. "
3469 "Out of system resources.");
3470 }
3471
3472 // Wait for the VM thread to become ready, and VMThread::run to initialize
3473 // Monitors can have spurious returns, must always check another state flag
3474 {
3475 MutexLocker ml(Notify_lock);
3476 os::start_thread(vmthread);
3477 while (vmthread->active_handles() == NULL) {
3478 Notify_lock->wait();
3479 }
3480 }
3481 }
3482
3483 assert(Universe::is_fully_initialized(), "not initialized");
3484 if (VerifyDuringStartup) {
3485 // Make sure we're starting with a clean slate.
3486 VM_Verify verify_op;
3487 VMThread::execute(&verify_op);
3488 }
3489
3490 Thread* THREAD = Thread::current();
3491
3492 // At this point, the Universe is initialized, but we have not executed
3493 // any byte code. Now is a good time (the only time) to dump out the
3494 // internal state of the JVM for sharing.
3495 if (DumpSharedSpaces) {
3496 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3497 ShouldNotReachHere();
3498 }
3499
3500 // Always call even when there are not JVMTI environments yet, since environments
3501 // may be attached late and JVMTI must track phases of VM execution
3502 JvmtiExport::enter_start_phase();
3503
3504 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3505 JvmtiExport::post_vm_start();
3506
3507 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3508
3509 // We need this for ClassDataSharing - the initial vm.info property is set
3510 // with the default value of CDS "sharing" which may be reset through
3511 // command line options.
3512 reset_vm_info_property(CHECK_JNI_ERR);
3513
3514 quicken_jni_functions();
3515
3516 // Must be run after init_ft which initializes ft_enabled
3517 if (TRACE_INITIALIZE() != JNI_OK) {
3518 vm_exit_during_initialization("Failed to initialize tracing backend");
3519 }
3520
3521 // Set flag that basic initialization has completed. Used by exceptions and various
3522 // debug stuff, that does not work until all basic classes have been initialized.
3523 set_init_completed();
3524
3525 Metaspace::post_initialize();
3526
3527 HOTSPOT_VM_INIT_END();
3528
3529 // record VM initialization completion time
3530 #if INCLUDE_MANAGEMENT
3531 Management::record_vm_init_completed();
3532 #endif // INCLUDE_MANAGEMENT
3533
3534 // Compute system loader. Note that this has to occur after set_init_completed, since
3535 // valid exceptions may be thrown in the process.
3536 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3537 // set_init_completed has just been called, causing exceptions not to be shortcut
3538 // anymore. We call vm_exit_during_initialization directly instead.
3539 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3540
3541 #if INCLUDE_ALL_GCS
3542 // Support for ConcurrentMarkSweep. This should be cleaned up
3543 // and better encapsulated. The ugly nested if test would go away
3544 // once things are properly refactored. XXX YSR
3545 if (UseConcMarkSweepGC || UseG1GC || UseShenandoahGC) {
3546 if (UseConcMarkSweepGC) {
3547 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3548 } else if (UseShenandoahGC) {
3549 ShenandoahConcurrentThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3550 } else {
3551 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3552 }
3553 }
3554 #endif // INCLUDE_ALL_GCS
3555
3556 // Always call even when there are not JVMTI environments yet, since environments
3557 // may be attached late and JVMTI must track phases of VM execution
3558 JvmtiExport::enter_live_phase();
3559
3560 // Signal Dispatcher needs to be started before VMInit event is posted
3561 os::signal_init();
3562
3563 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3564 if (!DisableAttachMechanism) {
3565 AttachListener::vm_start();
3566 if (StartAttachListener || AttachListener::init_at_startup()) {
3567 AttachListener::init();
3568 }
3569 }
3570
3571 // Launch -Xrun agents
3572 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3573 // back-end can launch with -Xdebug -Xrunjdwp.
3574 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3575 create_vm_init_libraries();
3576 }
3577
3578 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3579 JvmtiExport::post_vm_initialized();
3580
3581 if (TRACE_START() != JNI_OK) {
3582 vm_exit_during_initialization("Failed to start tracing backend.");
3583 }
3584
3585 if (CleanChunkPoolAsync) {
3586 Chunk::start_chunk_pool_cleaner_task();
3587 }
3588
3589 // initialize compiler(s)
3590 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3591 CompileBroker::compilation_init();
3592 #endif
3593
3594 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3595 // It is done after compilers are initialized, because otherwise compilations of
3596 // signature polymorphic MH intrinsics can be missed
3597 // (see SystemDictionary::find_method_handle_intrinsic).
3598 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3599
3600 #if INCLUDE_MANAGEMENT
3601 Management::initialize(THREAD);
3602
3603 if (HAS_PENDING_EXCEPTION) {
3604 // management agent fails to start possibly due to
3605 // configuration problem and is responsible for printing
3606 // stack trace if appropriate. Simply exit VM.
3607 vm_exit(1);
3608 }
3609 #endif // INCLUDE_MANAGEMENT
3610
3611 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3612 if (MemProfiling) MemProfiler::engage();
3613 StatSampler::engage();
3614 if (CheckJNICalls) JniPeriodicChecker::engage();
3615
3616 BiasedLocking::init();
3617
3618 #if INCLUDE_RTM_OPT
3619 RTMLockingCounters::init();
3620 #endif
3621
3622 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3623 call_postVMInitHook(THREAD);
3624 // The Java side of PostVMInitHook.run must deal with all
3625 // exceptions and provide means of diagnosis.
3626 if (HAS_PENDING_EXCEPTION) {
3627 CLEAR_PENDING_EXCEPTION;
3628 }
3629 }
3630
3631 {
3632 MutexLocker ml(PeriodicTask_lock);
3633 // Make sure the WatcherThread can be started by WatcherThread::start()
3634 // or by dynamic enrollment.
3635 WatcherThread::make_startable();
3636 // Start up the WatcherThread if there are any periodic tasks
3637 // NOTE: All PeriodicTasks should be registered by now. If they
3638 // aren't, late joiners might appear to start slowly (we might
3639 // take a while to process their first tick).
3640 if (PeriodicTask::num_tasks() > 0) {
3641 WatcherThread::start();
3642 }
3643 }
3644
3645 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3646
3647 create_vm_timer.end();
3648 #ifdef ASSERT
3649 _vm_complete = true;
3650 #endif
3651 return JNI_OK;
3652 }
3653
3654 // type for the Agent_OnLoad and JVM_OnLoad entry points
3655 extern "C" {
3656 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3657 }
3658 // Find a command line agent library and return its entry point for
3659 // -agentlib: -agentpath: -Xrun
3660 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3661 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3662 const char *on_load_symbols[],
3663 size_t num_symbol_entries) {
3664 OnLoadEntry_t on_load_entry = NULL;
3665 void *library = NULL;
3666
3667 if (!agent->valid()) {
3668 char buffer[JVM_MAXPATHLEN];
3669 char ebuf[1024] = "";
3670 const char *name = agent->name();
3671 const char *msg = "Could not find agent library ";
3672
3673 // First check to see if agent is statically linked into executable
3674 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3675 library = agent->os_lib();
3676 } else if (agent->is_absolute_path()) {
3677 library = os::dll_load(name, ebuf, sizeof ebuf);
3678 if (library == NULL) {
3679 const char *sub_msg = " in absolute path, with error: ";
3680 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3681 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3682 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3683 // If we can't find the agent, exit.
3684 vm_exit_during_initialization(buf, NULL);
3685 FREE_C_HEAP_ARRAY(char, buf);
3686 }
3687 } else {
3688 // Try to load the agent from the standard dll directory
3689 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3690 name)) {
3691 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3692 }
3693 if (library == NULL) { // Try the local directory
3694 char ns[1] = {0};
3695 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3696 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3697 }
3698 if (library == NULL) {
3699 const char *sub_msg = " on the library path, with error: ";
3700 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3701 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3702 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3703 // If we can't find the agent, exit.
3704 vm_exit_during_initialization(buf, NULL);
3705 FREE_C_HEAP_ARRAY(char, buf);
3706 }
3707 }
3708 }
3709 agent->set_os_lib(library);
3710 agent->set_valid();
3711 }
3712
3713 // Find the OnLoad function.
3714 on_load_entry =
3715 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3716 false,
3717 on_load_symbols,
3718 num_symbol_entries));
3719 return on_load_entry;
3720 }
3721
3722 // Find the JVM_OnLoad entry point
3723 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3724 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3725 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3726 }
3727
3728 // Find the Agent_OnLoad entry point
3729 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3730 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3731 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3732 }
3733
3734 // For backwards compatibility with -Xrun
3735 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3736 // treated like -agentpath:
3737 // Must be called before agent libraries are created
3738 void Threads::convert_vm_init_libraries_to_agents() {
3739 AgentLibrary* agent;
3740 AgentLibrary* next;
3741
3742 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3743 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3744 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3745
3746 // If there is an JVM_OnLoad function it will get called later,
3747 // otherwise see if there is an Agent_OnLoad
3748 if (on_load_entry == NULL) {
3749 on_load_entry = lookup_agent_on_load(agent);
3750 if (on_load_entry != NULL) {
3751 // switch it to the agent list -- so that Agent_OnLoad will be called,
3752 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3753 Arguments::convert_library_to_agent(agent);
3754 } else {
3755 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3756 }
3757 }
3758 }
3759 }
3760
3761 // Create agents for -agentlib: -agentpath: and converted -Xrun
3762 // Invokes Agent_OnLoad
3763 // Called very early -- before JavaThreads exist
3764 void Threads::create_vm_init_agents() {
3765 extern struct JavaVM_ main_vm;
3766 AgentLibrary* agent;
3767
3768 JvmtiExport::enter_onload_phase();
3769
3770 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3771 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3772
3773 if (on_load_entry != NULL) {
3774 // Invoke the Agent_OnLoad function
3775 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3776 if (err != JNI_OK) {
3777 vm_exit_during_initialization("agent library failed to init", agent->name());
3778 }
3779 } else {
3780 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3781 }
3782 }
3783 JvmtiExport::enter_primordial_phase();
3784 }
3785
3786 extern "C" {
3787 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3788 }
3789
3790 void Threads::shutdown_vm_agents() {
3791 // Send any Agent_OnUnload notifications
3792 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3793 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3794 extern struct JavaVM_ main_vm;
3795 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3796
3797 // Find the Agent_OnUnload function.
3798 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3799 os::find_agent_function(agent,
3800 false,
3801 on_unload_symbols,
3802 num_symbol_entries));
3803
3804 // Invoke the Agent_OnUnload function
3805 if (unload_entry != NULL) {
3806 JavaThread* thread = JavaThread::current();
3807 ThreadToNativeFromVM ttn(thread);
3808 HandleMark hm(thread);
3809 (*unload_entry)(&main_vm);
3810 }
3811 }
3812 }
3813
3814 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3815 // Invokes JVM_OnLoad
3816 void Threads::create_vm_init_libraries() {
3817 extern struct JavaVM_ main_vm;
3818 AgentLibrary* agent;
3819
3820 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3821 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3822
3823 if (on_load_entry != NULL) {
3824 // Invoke the JVM_OnLoad function
3825 JavaThread* thread = JavaThread::current();
3826 ThreadToNativeFromVM ttn(thread);
3827 HandleMark hm(thread);
3828 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3829 if (err != JNI_OK) {
3830 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3831 }
3832 } else {
3833 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3834 }
3835 }
3836 }
3837
3838 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3839 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3840
3841 JavaThread* java_thread = NULL;
3842 // Sequential search for now. Need to do better optimization later.
3843 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3844 oop tobj = thread->threadObj();
3845 if (!thread->is_exiting() &&
3846 tobj != NULL &&
3847 java_tid == java_lang_Thread::thread_id(tobj)) {
3848 java_thread = thread;
3849 break;
3850 }
3851 }
3852 return java_thread;
3853 }
3854
3855
3856 // Last thread running calls java.lang.Shutdown.shutdown()
3857 void JavaThread::invoke_shutdown_hooks() {
3858 HandleMark hm(this);
3859
3860 // We could get here with a pending exception, if so clear it now.
3861 if (this->has_pending_exception()) {
3862 this->clear_pending_exception();
3863 }
3864
3865 EXCEPTION_MARK;
3866 Klass* k =
3867 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3868 THREAD);
3869 if (k != NULL) {
3870 // SystemDictionary::resolve_or_null will return null if there was
3871 // an exception. If we cannot load the Shutdown class, just don't
3872 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3873 // and finalizers (if runFinalizersOnExit is set) won't be run.
3874 // Note that if a shutdown hook was registered or runFinalizersOnExit
3875 // was called, the Shutdown class would have already been loaded
3876 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3877 instanceKlassHandle shutdown_klass (THREAD, k);
3878 JavaValue result(T_VOID);
3879 JavaCalls::call_static(&result,
3880 shutdown_klass,
3881 vmSymbols::shutdown_method_name(),
3882 vmSymbols::void_method_signature(),
3883 THREAD);
3884 }
3885 CLEAR_PENDING_EXCEPTION;
3886 }
3887
3888 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3889 // the program falls off the end of main(). Another VM exit path is through
3890 // vm_exit() when the program calls System.exit() to return a value or when
3891 // there is a serious error in VM. The two shutdown paths are not exactly
3892 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3893 // and VM_Exit op at VM level.
3894 //
3895 // Shutdown sequence:
3896 // + Shutdown native memory tracking if it is on
3897 // + Wait until we are the last non-daemon thread to execute
3898 // <-- every thing is still working at this moment -->
3899 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3900 // shutdown hooks, run finalizers if finalization-on-exit
3901 // + Call before_exit(), prepare for VM exit
3902 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3903 // currently the only user of this mechanism is File.deleteOnExit())
3904 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3905 // post thread end and vm death events to JVMTI,
3906 // stop signal thread
3907 // + Call JavaThread::exit(), it will:
3908 // > release JNI handle blocks, remove stack guard pages
3909 // > remove this thread from Threads list
3910 // <-- no more Java code from this thread after this point -->
3911 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3912 // the compiler threads at safepoint
3913 // <-- do not use anything that could get blocked by Safepoint -->
3914 // + Disable tracing at JNI/JVM barriers
3915 // + Set _vm_exited flag for threads that are still running native code
3916 // + Delete this thread
3917 // + Call exit_globals()
3918 // > deletes tty
3919 // > deletes PerfMemory resources
3920 // + Return to caller
3921
3922 bool Threads::destroy_vm() {
3923 JavaThread* thread = JavaThread::current();
3924
3925 #ifdef ASSERT
3926 _vm_complete = false;
3927 #endif
3928 // Wait until we are the last non-daemon thread to execute
3929 { MutexLocker nu(Threads_lock);
3930 while (Threads::number_of_non_daemon_threads() > 1)
3931 // This wait should make safepoint checks, wait without a timeout,
3932 // and wait as a suspend-equivalent condition.
3933 //
3934 // Note: If the FlatProfiler is running and this thread is waiting
3935 // for another non-daemon thread to finish, then the FlatProfiler
3936 // is waiting for the external suspend request on this thread to
3937 // complete. wait_for_ext_suspend_completion() will eventually
3938 // timeout, but that takes time. Making this wait a suspend-
3939 // equivalent condition solves that timeout problem.
3940 //
3941 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3942 Mutex::_as_suspend_equivalent_flag);
3943 }
3944
3945 // Hang forever on exit if we are reporting an error.
3946 if (ShowMessageBoxOnError && is_error_reported()) {
3947 os::infinite_sleep();
3948 }
3949 os::wait_for_keypress_at_exit();
3950
3951 // run Java level shutdown hooks
3952 thread->invoke_shutdown_hooks();
3953
3954 before_exit(thread);
3955
3956 thread->exit(true);
3957
3958 // Stop GC threads.
3959 Universe::heap()->shutdown();
3960
3961 // Stop VM thread.
3962 {
3963 // 4945125 The vm thread comes to a safepoint during exit.
3964 // GC vm_operations can get caught at the safepoint, and the
3965 // heap is unparseable if they are caught. Grab the Heap_lock
3966 // to prevent this. The GC vm_operations will not be able to
3967 // queue until after the vm thread is dead. After this point,
3968 // we'll never emerge out of the safepoint before the VM exits.
3969
3970 MutexLocker ml(Heap_lock);
3971
3972 VMThread::wait_for_vm_thread_exit();
3973 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3974 VMThread::destroy();
3975 }
3976
3977 // clean up ideal graph printers
3978 #if defined(COMPILER2) && !defined(PRODUCT)
3979 IdealGraphPrinter::clean_up();
3980 #endif
3981
3982 // Now, all Java threads are gone except daemon threads. Daemon threads
3983 // running Java code or in VM are stopped by the Safepoint. However,
3984 // daemon threads executing native code are still running. But they
3985 // will be stopped at native=>Java/VM barriers. Note that we can't
3986 // simply kill or suspend them, as it is inherently deadlock-prone.
3987
3988 #ifndef PRODUCT
3989 // disable function tracing at JNI/JVM barriers
3990 TraceJNICalls = false;
3991 TraceJVMCalls = false;
3992 TraceRuntimeCalls = false;
3993 #endif
3994
3995 VM_Exit::set_vm_exited();
3996
3997 notify_vm_shutdown();
3998
3999 delete thread;
4000
4001 // exit_globals() will delete tty
4002 exit_globals();
4003
4004 return true;
4005 }
4006
4007
4008 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4009 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4010 return is_supported_jni_version(version);
4011 }
4012
4013
4014 jboolean Threads::is_supported_jni_version(jint version) {
4015 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4016 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4017 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4018 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4019 return JNI_FALSE;
4020 }
4021
4022
4023 void Threads::add(JavaThread* p, bool force_daemon) {
4024 // The threads lock must be owned at this point
4025 assert_locked_or_safepoint(Threads_lock);
4026
4027 // See the comment for this method in thread.hpp for its purpose and
4028 // why it is called here.
4029 p->initialize_queues();
4030 p->set_next(_thread_list);
4031 _thread_list = p;
4032 _number_of_threads++;
4033 oop threadObj = p->threadObj();
4034 bool daemon = true;
4035 // Bootstrapping problem: threadObj can be null for initial
4036 // JavaThread (or for threads attached via JNI)
4037 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4038 _number_of_non_daemon_threads++;
4039 daemon = false;
4040 }
4041
4042 ThreadService::add_thread(p, daemon);
4043
4044 // Possible GC point.
4045 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4046 }
4047
4048 void Threads::remove(JavaThread* p) {
4049 // Extra scope needed for Thread_lock, so we can check
4050 // that we do not remove thread without safepoint code notice
4051 { MutexLocker ml(Threads_lock);
4052
4053 assert(includes(p), "p must be present");
4054
4055 JavaThread* current = _thread_list;
4056 JavaThread* prev = NULL;
4057
4058 while (current != p) {
4059 prev = current;
4060 current = current->next();
4061 }
4062
4063 if (prev) {
4064 prev->set_next(current->next());
4065 } else {
4066 _thread_list = p->next();
4067 }
4068 _number_of_threads--;
4069 oop threadObj = p->threadObj();
4070 bool daemon = true;
4071 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4072 _number_of_non_daemon_threads--;
4073 daemon = false;
4074
4075 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4076 // on destroy_vm will wake up.
4077 if (number_of_non_daemon_threads() == 1) {
4078 Threads_lock->notify_all();
4079 }
4080 }
4081 ThreadService::remove_thread(p, daemon);
4082
4083 // Make sure that safepoint code disregard this thread. This is needed since
4084 // the thread might mess around with locks after this point. This can cause it
4085 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4086 // of this thread since it is removed from the queue.
4087 p->set_terminated_value();
4088 } // unlock Threads_lock
4089
4090 // Since Events::log uses a lock, we grab it outside the Threads_lock
4091 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4092 }
4093
4094 // Threads_lock must be held when this is called (or must be called during a safepoint)
4095 bool Threads::includes(JavaThread* p) {
4096 assert(Threads_lock->is_locked(), "sanity check");
4097 ALL_JAVA_THREADS(q) {
4098 if (q == p) {
4099 return true;
4100 }
4101 }
4102 return false;
4103 }
4104
4105 // Operations on the Threads list for GC. These are not explicitly locked,
4106 // but the garbage collector must provide a safe context for them to run.
4107 // In particular, these things should never be called when the Threads_lock
4108 // is held by some other thread. (Note: the Safepoint abstraction also
4109 // uses the Threads_lock to guarantee this property. It also makes sure that
4110 // all threads gets blocked when exiting or starting).
4111
4112 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4113 ALL_JAVA_THREADS(p) {
4114 p->oops_do(f, cld_f, cf);
4115 }
4116 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4117 }
4118
4119 void Threads::change_thread_claim_parity() {
4120 // Set the new claim parity.
4121 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4122 "Not in range.");
4123 _thread_claim_parity++;
4124 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4125 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4126 "Not in range.");
4127 }
4128
4129 #ifdef ASSERT
4130 void Threads::assert_all_threads_claimed() {
4131 ALL_JAVA_THREADS(p) {
4132 const int thread_parity = p->oops_do_parity();
4133 assert((thread_parity == _thread_claim_parity),
4134 err_msg("Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity));
4135 }
4136 }
4137 #endif // ASSERT
4138
4139 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4140 int cp = Threads::thread_claim_parity();
4141 ALL_JAVA_THREADS(p) {
4142 if (p->claim_oops_do(is_par, cp)) {
4143 p->oops_do(f, cld_f, cf);
4144 }
4145 }
4146 VMThread* vmt = VMThread::vm_thread();
4147 if (vmt->claim_oops_do(is_par, cp)) {
4148 vmt->oops_do(f, cld_f, cf);
4149 }
4150 }
4151
4152 #if INCLUDE_ALL_GCS
4153 // Used by ParallelScavenge
4154 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4155 ALL_JAVA_THREADS(p) {
4156 q->enqueue(new ThreadRootsTask(p));
4157 }
4158 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4159 }
4160
4161 // Used by Parallel Old
4162 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4163 ALL_JAVA_THREADS(p) {
4164 q->enqueue(new ThreadRootsMarkingTask(p));
4165 }
4166 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4167 }
4168 #endif // INCLUDE_ALL_GCS
4169
4170 void Threads::nmethods_do(CodeBlobClosure* cf) {
4171 ALL_JAVA_THREADS(p) {
4172 p->nmethods_do(cf);
4173 }
4174 VMThread::vm_thread()->nmethods_do(cf);
4175 }
4176
4177 void Threads::metadata_do(void f(Metadata*)) {
4178 ALL_JAVA_THREADS(p) {
4179 p->metadata_do(f);
4180 }
4181 }
4182
4183 class ThreadHandlesClosure : public ThreadClosure {
4184 void (*_f)(Metadata*);
4185 public:
4186 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4187 virtual void do_thread(Thread* thread) {
4188 thread->metadata_handles_do(_f);
4189 }
4190 };
4191
4192 void Threads::metadata_handles_do(void f(Metadata*)) {
4193 // Only walk the Handles in Thread.
4194 ThreadHandlesClosure handles_closure(f);
4195 threads_do(&handles_closure);
4196 }
4197
4198 void Threads::deoptimized_wrt_marked_nmethods() {
4199 ALL_JAVA_THREADS(p) {
4200 p->deoptimized_wrt_marked_nmethods();
4201 }
4202 }
4203
4204
4205 // Get count Java threads that are waiting to enter the specified monitor.
4206 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4207 address monitor,
4208 bool doLock) {
4209 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4210 "must grab Threads_lock or be at safepoint");
4211 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4212
4213 int i = 0;
4214 {
4215 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4216 ALL_JAVA_THREADS(p) {
4217 if (p->is_Compiler_thread()) continue;
4218
4219 address pending = (address)p->current_pending_monitor();
4220 if (pending == monitor) { // found a match
4221 if (i < count) result->append(p); // save the first count matches
4222 i++;
4223 }
4224 }
4225 }
4226 return result;
4227 }
4228
4229
4230 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4231 bool doLock) {
4232 assert(doLock ||
4233 Threads_lock->owned_by_self() ||
4234 SafepointSynchronize::is_at_safepoint(),
4235 "must grab Threads_lock or be at safepoint");
4236
4237 // NULL owner means not locked so we can skip the search
4238 if (owner == NULL) return NULL;
4239
4240 {
4241 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4242 ALL_JAVA_THREADS(p) {
4243 // first, see if owner is the address of a Java thread
4244 if (owner == (address)p) return p;
4245 }
4246 }
4247 // Cannot assert on lack of success here since this function may be
4248 // used by code that is trying to report useful problem information
4249 // like deadlock detection.
4250 if (UseHeavyMonitors) return NULL;
4251
4252 // If we didn't find a matching Java thread and we didn't force use of
4253 // heavyweight monitors, then the owner is the stack address of the
4254 // Lock Word in the owning Java thread's stack.
4255 //
4256 JavaThread* the_owner = NULL;
4257 {
4258 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4259 ALL_JAVA_THREADS(q) {
4260 if (q->is_lock_owned(owner)) {
4261 the_owner = q;
4262 break;
4263 }
4264 }
4265 }
4266 // cannot assert on lack of success here; see above comment
4267 return the_owner;
4268 }
4269
4270 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4271 void Threads::print_on(outputStream* st, bool print_stacks,
4272 bool internal_format, bool print_concurrent_locks) {
4273 char buf[32];
4274 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4275
4276 st->print_cr("Full thread dump %s (%s %s):",
4277 Abstract_VM_Version::vm_name(),
4278 Abstract_VM_Version::vm_release(),
4279 Abstract_VM_Version::vm_info_string());
4280 st->cr();
4281
4282 #if INCLUDE_SERVICES
4283 // Dump concurrent locks
4284 ConcurrentLocksDump concurrent_locks;
4285 if (print_concurrent_locks) {
4286 concurrent_locks.dump_at_safepoint();
4287 }
4288 #endif // INCLUDE_SERVICES
4289
4290 ALL_JAVA_THREADS(p) {
4291 ResourceMark rm;
4292 p->print_on(st);
4293 if (print_stacks) {
4294 if (internal_format) {
4295 p->trace_stack();
4296 } else {
4297 p->print_stack_on(st);
4298 }
4299 }
4300 st->cr();
4301 #if INCLUDE_SERVICES
4302 if (print_concurrent_locks) {
4303 concurrent_locks.print_locks_on(p, st);
4304 }
4305 #endif // INCLUDE_SERVICES
4306 }
4307
4308 VMThread::vm_thread()->print_on(st);
4309 st->cr();
4310 Universe::heap()->print_gc_threads_on(st);
4311 WatcherThread* wt = WatcherThread::watcher_thread();
4312 if (wt != NULL) {
4313 wt->print_on(st);
4314 st->cr();
4315 }
4316 CompileBroker::print_compiler_threads_on(st);
4317 st->flush();
4318 }
4319
4320 // Threads::print_on_error() is called by fatal error handler. It's possible
4321 // that VM is not at safepoint and/or current thread is inside signal handler.
4322 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4323 // memory (even in resource area), it might deadlock the error handler.
4324 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4325 int buflen) {
4326 bool found_current = false;
4327 st->print_cr("Java Threads: ( => current thread )");
4328 ALL_JAVA_THREADS(thread) {
4329 bool is_current = (current == thread);
4330 found_current = found_current || is_current;
4331
4332 st->print("%s", is_current ? "=>" : " ");
4333
4334 st->print(PTR_FORMAT, thread);
4335 st->print(" ");
4336 thread->print_on_error(st, buf, buflen);
4337 st->cr();
4338 }
4339 st->cr();
4340
4341 st->print_cr("Other Threads:");
4342 if (VMThread::vm_thread()) {
4343 bool is_current = (current == VMThread::vm_thread());
4344 found_current = found_current || is_current;
4345 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4346
4347 st->print(PTR_FORMAT, VMThread::vm_thread());
4348 st->print(" ");
4349 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4350 st->cr();
4351 }
4352 WatcherThread* wt = WatcherThread::watcher_thread();
4353 if (wt != NULL) {
4354 bool is_current = (current == wt);
4355 found_current = found_current || is_current;
4356 st->print("%s", is_current ? "=>" : " ");
4357
4358 st->print(PTR_FORMAT, wt);
4359 st->print(" ");
4360 wt->print_on_error(st, buf, buflen);
4361 st->cr();
4362 }
4363 if (!found_current) {
4364 st->cr();
4365 st->print("=>" PTR_FORMAT " (exited) ", current);
4366 current->print_on_error(st, buf, buflen);
4367 st->cr();
4368 }
4369 }
4370
4371 // Internal SpinLock and Mutex
4372 // Based on ParkEvent
4373
4374 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4375 //
4376 // We employ SpinLocks _only for low-contention, fixed-length
4377 // short-duration critical sections where we're concerned
4378 // about native mutex_t or HotSpot Mutex:: latency.
4379 // The mux construct provides a spin-then-block mutual exclusion
4380 // mechanism.
4381 //
4382 // Testing has shown that contention on the ListLock guarding gFreeList
4383 // is common. If we implement ListLock as a simple SpinLock it's common
4384 // for the JVM to devolve to yielding with little progress. This is true
4385 // despite the fact that the critical sections protected by ListLock are
4386 // extremely short.
4387 //
4388 // TODO-FIXME: ListLock should be of type SpinLock.
4389 // We should make this a 1st-class type, integrated into the lock
4390 // hierarchy as leaf-locks. Critically, the SpinLock structure
4391 // should have sufficient padding to avoid false-sharing and excessive
4392 // cache-coherency traffic.
4393
4394
4395 typedef volatile int SpinLockT;
4396
4397 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4398 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4399 return; // normal fast-path return
4400 }
4401
4402 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4403 TEVENT(SpinAcquire - ctx);
4404 int ctr = 0;
4405 int Yields = 0;
4406 for (;;) {
4407 while (*adr != 0) {
4408 ++ctr;
4409 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4410 if (Yields > 5) {
4411 os::naked_short_sleep(1);
4412 } else {
4413 os::naked_yield();
4414 ++Yields;
4415 }
4416 } else {
4417 SpinPause();
4418 }
4419 }
4420 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4421 }
4422 }
4423
4424 void Thread::SpinRelease(volatile int * adr) {
4425 assert(*adr != 0, "invariant");
4426 OrderAccess::fence(); // guarantee at least release consistency.
4427 // Roach-motel semantics.
4428 // It's safe if subsequent LDs and STs float "up" into the critical section,
4429 // but prior LDs and STs within the critical section can't be allowed
4430 // to reorder or float past the ST that releases the lock.
4431 // Loads and stores in the critical section - which appear in program
4432 // order before the store that releases the lock - must also appear
4433 // before the store that releases the lock in memory visibility order.
4434 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4435 // the ST of 0 into the lock-word which releases the lock, so fence
4436 // more than covers this on all platforms.
4437 *adr = 0;
4438 }
4439
4440 // muxAcquire and muxRelease:
4441 //
4442 // * muxAcquire and muxRelease support a single-word lock-word construct.
4443 // The LSB of the word is set IFF the lock is held.
4444 // The remainder of the word points to the head of a singly-linked list
4445 // of threads blocked on the lock.
4446 //
4447 // * The current implementation of muxAcquire-muxRelease uses its own
4448 // dedicated Thread._MuxEvent instance. If we're interested in
4449 // minimizing the peak number of extant ParkEvent instances then
4450 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4451 // as certain invariants were satisfied. Specifically, care would need
4452 // to be taken with regards to consuming unpark() "permits".
4453 // A safe rule of thumb is that a thread would never call muxAcquire()
4454 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4455 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4456 // consume an unpark() permit intended for monitorenter, for instance.
4457 // One way around this would be to widen the restricted-range semaphore
4458 // implemented in park(). Another alternative would be to provide
4459 // multiple instances of the PlatformEvent() for each thread. One
4460 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4461 //
4462 // * Usage:
4463 // -- Only as leaf locks
4464 // -- for short-term locking only as muxAcquire does not perform
4465 // thread state transitions.
4466 //
4467 // Alternatives:
4468 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4469 // but with parking or spin-then-park instead of pure spinning.
4470 // * Use Taura-Oyama-Yonenzawa locks.
4471 // * It's possible to construct a 1-0 lock if we encode the lockword as
4472 // (List,LockByte). Acquire will CAS the full lockword while Release
4473 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4474 // acquiring threads use timers (ParkTimed) to detect and recover from
4475 // the stranding window. Thread/Node structures must be aligned on 256-byte
4476 // boundaries by using placement-new.
4477 // * Augment MCS with advisory back-link fields maintained with CAS().
4478 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4479 // The validity of the backlinks must be ratified before we trust the value.
4480 // If the backlinks are invalid the exiting thread must back-track through the
4481 // the forward links, which are always trustworthy.
4482 // * Add a successor indication. The LockWord is currently encoded as
4483 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4484 // to provide the usual futile-wakeup optimization.
4485 // See RTStt for details.
4486 // * Consider schedctl.sc_nopreempt to cover the critical section.
4487 //
4488
4489
4490 typedef volatile intptr_t MutexT; // Mux Lock-word
4491 enum MuxBits { LOCKBIT = 1 };
4492
4493 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4494 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4495 if (w == 0) return;
4496 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4497 return;
4498 }
4499
4500 TEVENT(muxAcquire - Contention);
4501 ParkEvent * const Self = Thread::current()->_MuxEvent;
4502 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4503 for (;;) {
4504 int its = (os::is_MP() ? 100 : 0) + 1;
4505
4506 // Optional spin phase: spin-then-park strategy
4507 while (--its >= 0) {
4508 w = *Lock;
4509 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4510 return;
4511 }
4512 }
4513
4514 Self->reset();
4515 Self->OnList = intptr_t(Lock);
4516 // The following fence() isn't _strictly necessary as the subsequent
4517 // CAS() both serializes execution and ratifies the fetched *Lock value.
4518 OrderAccess::fence();
4519 for (;;) {
4520 w = *Lock;
4521 if ((w & LOCKBIT) == 0) {
4522 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4523 Self->OnList = 0; // hygiene - allows stronger asserts
4524 return;
4525 }
4526 continue; // Interference -- *Lock changed -- Just retry
4527 }
4528 assert(w & LOCKBIT, "invariant");
4529 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4530 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4531 }
4532
4533 while (Self->OnList != 0) {
4534 Self->park();
4535 }
4536 }
4537 }
4538
4539 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4540 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4541 if (w == 0) return;
4542 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4543 return;
4544 }
4545
4546 TEVENT(muxAcquire - Contention);
4547 ParkEvent * ReleaseAfter = NULL;
4548 if (ev == NULL) {
4549 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4550 }
4551 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4552 for (;;) {
4553 guarantee(ev->OnList == 0, "invariant");
4554 int its = (os::is_MP() ? 100 : 0) + 1;
4555
4556 // Optional spin phase: spin-then-park strategy
4557 while (--its >= 0) {
4558 w = *Lock;
4559 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4560 if (ReleaseAfter != NULL) {
4561 ParkEvent::Release(ReleaseAfter);
4562 }
4563 return;
4564 }
4565 }
4566
4567 ev->reset();
4568 ev->OnList = intptr_t(Lock);
4569 // The following fence() isn't _strictly necessary as the subsequent
4570 // CAS() both serializes execution and ratifies the fetched *Lock value.
4571 OrderAccess::fence();
4572 for (;;) {
4573 w = *Lock;
4574 if ((w & LOCKBIT) == 0) {
4575 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4576 ev->OnList = 0;
4577 // We call ::Release while holding the outer lock, thus
4578 // artificially lengthening the critical section.
4579 // Consider deferring the ::Release() until the subsequent unlock(),
4580 // after we've dropped the outer lock.
4581 if (ReleaseAfter != NULL) {
4582 ParkEvent::Release(ReleaseAfter);
4583 }
4584 return;
4585 }
4586 continue; // Interference -- *Lock changed -- Just retry
4587 }
4588 assert(w & LOCKBIT, "invariant");
4589 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4590 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4591 }
4592
4593 while (ev->OnList != 0) {
4594 ev->park();
4595 }
4596 }
4597 }
4598
4599 // Release() must extract a successor from the list and then wake that thread.
4600 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4601 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4602 // Release() would :
4603 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4604 // (B) Extract a successor from the private list "in-hand"
4605 // (C) attempt to CAS() the residual back into *Lock over null.
4606 // If there were any newly arrived threads and the CAS() would fail.
4607 // In that case Release() would detach the RATs, re-merge the list in-hand
4608 // with the RATs and repeat as needed. Alternately, Release() might
4609 // detach and extract a successor, but then pass the residual list to the wakee.
4610 // The wakee would be responsible for reattaching and remerging before it
4611 // competed for the lock.
4612 //
4613 // Both "pop" and DMR are immune from ABA corruption -- there can be
4614 // multiple concurrent pushers, but only one popper or detacher.
4615 // This implementation pops from the head of the list. This is unfair,
4616 // but tends to provide excellent throughput as hot threads remain hot.
4617 // (We wake recently run threads first).
4618 //
4619 // All paths through muxRelease() will execute a CAS.
4620 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4621 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4622 // executed within the critical section are complete and globally visible before the
4623 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4624 void Thread::muxRelease(volatile intptr_t * Lock) {
4625 for (;;) {
4626 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4627 assert(w & LOCKBIT, "invariant");
4628 if (w == LOCKBIT) return;
4629 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4630 assert(List != NULL, "invariant");
4631 assert(List->OnList == intptr_t(Lock), "invariant");
4632 ParkEvent * const nxt = List->ListNext;
4633 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4634
4635 // The following CAS() releases the lock and pops the head element.
4636 // The CAS() also ratifies the previously fetched lock-word value.
4637 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4638 continue;
4639 }
4640 List->OnList = 0;
4641 OrderAccess::fence();
4642 List->unpark();
4643 return;
4644 }
4645 }
4646
4647
4648 void Threads::verify() {
4649 ALL_JAVA_THREADS(p) {
4650 p->verify();
4651 }
4652 VMThread* thread = VMThread::vm_thread();
4653 if (thread != NULL) thread->verify();
4654 }