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 assert(this == watcher_thread(), "just checking");
1272
1273 this->record_stack_base_and_size();
1274 this->initialize_thread_local_storage();
1275 this->set_native_thread_name(this->name());
1276 this->set_active_handles(JNIHandleBlock::allocate_block());
1277 while (true) {
1278 assert(watcher_thread() == Thread::current(), "thread consistency check");
1279 assert(watcher_thread() == this, "thread consistency check");
1280
1281 // Calculate how long it'll be until the next PeriodicTask work
1282 // should be done, and sleep that amount of time.
1283 int time_waited = sleep();
1284
1285 if (is_error_reported()) {
1286 // A fatal error has happened, the error handler(VMError::report_and_die)
1287 // should abort JVM after creating an error log file. However in some
1288 // rare cases, the error handler itself might deadlock. Here we try to
1289 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1290 //
1291 // This code is in WatcherThread because WatcherThread wakes up
1292 // periodically so the fatal error handler doesn't need to do anything;
1293 // also because the WatcherThread is less likely to crash than other
1294 // threads.
1295
1296 for (;;) {
1297 if (!ShowMessageBoxOnError
1298 && (OnError == NULL || OnError[0] == '\0')
1299 && Arguments::abort_hook() == NULL) {
1300 os::sleep(this, ErrorLogTimeout * 60 * 1000, false);
1301 fdStream err(defaultStream::output_fd());
1302 err.print_raw_cr("# [ timer expired, abort... ]");
1303 // skip atexit/vm_exit/vm_abort hooks
1304 os::die();
1305 }
1306
1307 // Wake up 5 seconds later, the fatal handler may reset OnError or
1308 // ShowMessageBoxOnError when it is ready to abort.
1309 os::sleep(this, 5 * 1000, false);
1310 }
1311 }
1312
1313 if (_should_terminate) {
1314 // check for termination before posting the next tick
1315 break;
1316 }
1317
1318 PeriodicTask::real_time_tick(time_waited);
1319 }
1320
1321 // Signal that it is terminated
1322 {
1323 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1324 _watcher_thread = NULL;
1325 Terminator_lock->notify();
1326 }
1327
1328 // Thread destructor usually does this..
1329 ThreadLocalStorage::set_thread(NULL);
1330 }
1331
1332 void WatcherThread::start() {
1333 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1334
1335 if (watcher_thread() == NULL && _startable) {
1336 _should_terminate = false;
1337 // Create the single instance of WatcherThread
1338 new WatcherThread();
1339 }
1340 }
1341
1342 void WatcherThread::make_startable() {
1343 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1344 _startable = true;
1345 }
1346
1347 void WatcherThread::stop() {
1348 {
1349 // Follow normal safepoint aware lock enter protocol since the
1350 // WatcherThread is stopped by another JavaThread.
1351 MutexLocker ml(PeriodicTask_lock);
1352 _should_terminate = true;
1353
1354 WatcherThread* watcher = watcher_thread();
1355 if (watcher != NULL) {
1356 // unpark the WatcherThread so it can see that it should terminate
1357 watcher->unpark();
1358 }
1359 }
1360
1361 MutexLocker mu(Terminator_lock);
1362
1363 while (watcher_thread() != NULL) {
1364 // This wait should make safepoint checks, wait without a timeout,
1365 // and wait as a suspend-equivalent condition.
1366 //
1367 // Note: If the FlatProfiler is running, then this thread is waiting
1368 // for the WatcherThread to terminate and the WatcherThread, via the
1369 // FlatProfiler task, is waiting for the external suspend request on
1370 // this thread to complete. wait_for_ext_suspend_completion() will
1371 // eventually timeout, but that takes time. Making this wait a
1372 // suspend-equivalent condition solves that timeout problem.
1373 //
1374 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1375 Mutex::_as_suspend_equivalent_flag);
1376 }
1377 }
1378
1379 void WatcherThread::unpark() {
1380 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1381 PeriodicTask_lock->notify();
1382 }
1383
1384 void WatcherThread::print_on(outputStream* st) const {
1385 st->print("\"%s\" ", name());
1386 Thread::print_on(st);
1387 st->cr();
1388 }
1389
1390 // ======= JavaThread ========
1391
1392 // A JavaThread is a normal Java thread
1393
1394 void JavaThread::initialize() {
1395 // Initialize fields
1396
1397 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1398 set_claimed_par_id(UINT_MAX);
1399
1400 set_saved_exception_pc(NULL);
1401 set_threadObj(NULL);
1402 _anchor.clear();
1403 set_entry_point(NULL);
1404 set_jni_functions(jni_functions());
1405 set_callee_target(NULL);
1406 set_vm_result(NULL);
1407 set_vm_result_2(NULL);
1408 set_vframe_array_head(NULL);
1409 set_vframe_array_last(NULL);
1410 set_deferred_locals(NULL);
1411 set_deopt_mark(NULL);
1412 set_deopt_nmethod(NULL);
1413 clear_must_deopt_id();
1414 set_monitor_chunks(NULL);
1415 set_next(NULL);
1416 set_thread_state(_thread_new);
1417 _terminated = _not_terminated;
1418 _privileged_stack_top = NULL;
1419 _array_for_gc = NULL;
1420 _suspend_equivalent = false;
1421 _in_deopt_handler = 0;
1422 _doing_unsafe_access = false;
1423 _stack_guard_state = stack_guard_unused;
1424 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1425 _exception_pc = 0;
1426 _exception_handler_pc = 0;
1427 _is_method_handle_return = 0;
1428 _jvmti_thread_state= NULL;
1429 _should_post_on_exceptions_flag = JNI_FALSE;
1430 _jvmti_get_loaded_classes_closure = NULL;
1431 _interp_only_mode = 0;
1432 _special_runtime_exit_condition = _no_async_condition;
1433 _pending_async_exception = NULL;
1434 _thread_stat = NULL;
1435 _thread_stat = new ThreadStatistics();
1436 _blocked_on_compilation = false;
1437 _jni_active_critical = 0;
1438 _pending_jni_exception_check_fn = NULL;
1439 _do_not_unlock_if_synchronized = false;
1440 _cached_monitor_info = NULL;
1441 _parker = Parker::Allocate(this);
1442
1443 #ifndef PRODUCT
1444 _jmp_ring_index = 0;
1445 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1446 record_jump(NULL, NULL, NULL, 0);
1447 }
1448 #endif // PRODUCT
1449
1450 set_thread_profiler(NULL);
1451 if (FlatProfiler::is_active()) {
1452 // This is where we would decide to either give each thread it's own profiler
1453 // or use one global one from FlatProfiler,
1454 // or up to some count of the number of profiled threads, etc.
1455 ThreadProfiler* pp = new ThreadProfiler();
1456 pp->engage();
1457 set_thread_profiler(pp);
1458 }
1459
1460 // Setup safepoint state info for this thread
1461 ThreadSafepointState::create(this);
1462
1463 debug_only(_java_call_counter = 0);
1464
1465 // JVMTI PopFrame support
1466 _popframe_condition = popframe_inactive;
1467 _popframe_preserved_args = NULL;
1468 _popframe_preserved_args_size = 0;
1469 _frames_to_pop_failed_realloc = 0;
1470
1471 pd_initialize();
1472 }
1473
1474 #if INCLUDE_ALL_GCS
1475 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1476 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1477 bool JavaThread::_evacuation_in_progress_global = false;
1478 #endif // INCLUDE_ALL_GCS
1479
1480 JavaThread::JavaThread(bool is_attaching_via_jni) :
1481 Thread()
1482 #if INCLUDE_ALL_GCS
1483 , _satb_mark_queue(&_satb_mark_queue_set),
1484 _dirty_card_queue(&_dirty_card_queue_set),
1485 _evacuation_in_progress(_evacuation_in_progress_global)
1486 #endif // INCLUDE_ALL_GCS
1487 {
1488 initialize();
1489 if (is_attaching_via_jni) {
1490 _jni_attach_state = _attaching_via_jni;
1491 } else {
1492 _jni_attach_state = _not_attaching_via_jni;
1493 }
1494 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1495 }
1496
1497 bool JavaThread::reguard_stack(address cur_sp) {
1498 if (_stack_guard_state != stack_guard_yellow_disabled) {
1499 return true; // Stack already guarded or guard pages not needed.
1500 }
1501
1502 if (register_stack_overflow()) {
1503 // For those architectures which have separate register and
1504 // memory stacks, we must check the register stack to see if
1505 // it has overflowed.
1506 return false;
1507 }
1508
1509 // Java code never executes within the yellow zone: the latter is only
1510 // there to provoke an exception during stack banging. If java code
1511 // is executing there, either StackShadowPages should be larger, or
1512 // some exception code in c1, c2 or the interpreter isn't unwinding
1513 // when it should.
1514 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1515
1516 enable_stack_yellow_zone();
1517 return true;
1518 }
1519
1520 bool JavaThread::reguard_stack(void) {
1521 return reguard_stack(os::current_stack_pointer());
1522 }
1523
1524
1525 void JavaThread::block_if_vm_exited() {
1526 if (_terminated == _vm_exited) {
1527 // _vm_exited is set at safepoint, and Threads_lock is never released
1528 // we will block here forever
1529 Threads_lock->lock_without_safepoint_check();
1530 ShouldNotReachHere();
1531 }
1532 }
1533
1534
1535 // Remove this ifdef when C1 is ported to the compiler interface.
1536 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1537 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1538
1539 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1540 Thread()
1541 #if INCLUDE_ALL_GCS
1542 , _satb_mark_queue(&_satb_mark_queue_set),
1543 _dirty_card_queue(&_dirty_card_queue_set),
1544 _evacuation_in_progress(_evacuation_in_progress_global)
1545 #endif // INCLUDE_ALL_GCS
1546 {
1547 initialize();
1548 _jni_attach_state = _not_attaching_via_jni;
1549 set_entry_point(entry_point);
1550 // Create the native thread itself.
1551 // %note runtime_23
1552 os::ThreadType thr_type = os::java_thread;
1553 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1554 os::java_thread;
1555 os::create_thread(this, thr_type, stack_sz);
1556 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1557 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1558 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1559 // the exception consists of creating the exception object & initializing it, initialization
1560 // will leave the VM via a JavaCall and then all locks must be unlocked).
1561 //
1562 // The thread is still suspended when we reach here. Thread must be explicit started
1563 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1564 // by calling Threads:add. The reason why this is not done here, is because the thread
1565 // object must be fully initialized (take a look at JVM_Start)
1566 }
1567
1568 JavaThread::~JavaThread() {
1569
1570 // JSR166 -- return the parker to the free list
1571 Parker::Release(_parker);
1572 _parker = NULL;
1573
1574 // Free any remaining previous UnrollBlock
1575 vframeArray* old_array = vframe_array_last();
1576
1577 if (old_array != NULL) {
1578 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1579 old_array->set_unroll_block(NULL);
1580 delete old_info;
1581 delete old_array;
1582 }
1583
1584 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1585 if (deferred != NULL) {
1586 // This can only happen if thread is destroyed before deoptimization occurs.
1587 assert(deferred->length() != 0, "empty array!");
1588 do {
1589 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1590 deferred->remove_at(0);
1591 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1592 delete dlv;
1593 } while (deferred->length() != 0);
1594 delete deferred;
1595 }
1596
1597 // All Java related clean up happens in exit
1598 ThreadSafepointState::destroy(this);
1599 if (_thread_profiler != NULL) delete _thread_profiler;
1600 if (_thread_stat != NULL) delete _thread_stat;
1601 }
1602
1603
1604 // The first routine called by a new Java thread
1605 void JavaThread::run() {
1606 // initialize thread-local alloc buffer related fields
1607 this->initialize_tlab();
1608
1609 // used to test validity of stack trace backs
1610 this->record_base_of_stack_pointer();
1611
1612 // Record real stack base and size.
1613 this->record_stack_base_and_size();
1614
1615 // Initialize thread local storage; set before calling MutexLocker
1616 this->initialize_thread_local_storage();
1617
1618 this->create_stack_guard_pages();
1619
1620 this->cache_global_variables();
1621
1622 // Thread is now sufficient initialized to be handled by the safepoint code as being
1623 // in the VM. Change thread state from _thread_new to _thread_in_vm
1624 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1625
1626 assert(JavaThread::current() == this, "sanity check");
1627 assert(!Thread::current()->owns_locks(), "sanity check");
1628
1629 DTRACE_THREAD_PROBE(start, this);
1630
1631 // This operation might block. We call that after all safepoint checks for a new thread has
1632 // been completed.
1633 this->set_active_handles(JNIHandleBlock::allocate_block());
1634
1635 if (JvmtiExport::should_post_thread_life()) {
1636 JvmtiExport::post_thread_start(this);
1637 }
1638
1639 EventThreadStart event;
1640 if (event.should_commit()) {
1641 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1642 event.commit();
1643 }
1644
1645 // We call another function to do the rest so we are sure that the stack addresses used
1646 // from there will be lower than the stack base just computed
1647 thread_main_inner();
1648
1649 // Note, thread is no longer valid at this point!
1650 }
1651
1652
1653 void JavaThread::thread_main_inner() {
1654 assert(JavaThread::current() == this, "sanity check");
1655 assert(this->threadObj() != NULL, "just checking");
1656
1657 // Execute thread entry point unless this thread has a pending exception
1658 // or has been stopped before starting.
1659 // Note: Due to JVM_StopThread we can have pending exceptions already!
1660 if (!this->has_pending_exception() &&
1661 !java_lang_Thread::is_stillborn(this->threadObj())) {
1662 {
1663 ResourceMark rm(this);
1664 this->set_native_thread_name(this->get_thread_name());
1665 }
1666 HandleMark hm(this);
1667 this->entry_point()(this, this);
1668 }
1669
1670 DTRACE_THREAD_PROBE(stop, this);
1671
1672 this->exit(false);
1673 delete this;
1674 }
1675
1676
1677 static void ensure_join(JavaThread* thread) {
1678 // We do not need to grap the Threads_lock, since we are operating on ourself.
1679 Handle threadObj(thread, oopDesc::bs()->write_barrier(thread->threadObj()));
1680 assert(threadObj.not_null(), "java thread object must exist");
1681 ObjectLocker lock(threadObj, thread);
1682 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1683 thread->clear_pending_exception();
1684 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1685 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1686 // Clear the native thread instance - this makes isAlive return false and allows the join()
1687 // to complete once we've done the notify_all below
1688 java_lang_Thread::set_thread(threadObj(), NULL);
1689 lock.notify_all(thread);
1690 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1691 thread->clear_pending_exception();
1692 }
1693
1694
1695 // For any new cleanup additions, please check to see if they need to be applied to
1696 // cleanup_failed_attach_current_thread as well.
1697 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1698 assert(this == JavaThread::current(), "thread consistency check");
1699
1700 HandleMark hm(this);
1701 Handle uncaught_exception(this, this->pending_exception());
1702 this->clear_pending_exception();
1703 Handle threadObj(this, this->threadObj());
1704 assert(threadObj.not_null(), "Java thread object should be created");
1705
1706 if (get_thread_profiler() != NULL) {
1707 get_thread_profiler()->disengage();
1708 ResourceMark rm;
1709 get_thread_profiler()->print(get_thread_name());
1710 }
1711
1712
1713 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1714 {
1715 EXCEPTION_MARK;
1716
1717 CLEAR_PENDING_EXCEPTION;
1718 }
1719 if (!destroy_vm) {
1720 if (uncaught_exception.not_null()) {
1721 EXCEPTION_MARK;
1722 // Call method Thread.dispatchUncaughtException().
1723 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1724 JavaValue result(T_VOID);
1725 JavaCalls::call_virtual(&result,
1726 threadObj, thread_klass,
1727 vmSymbols::dispatchUncaughtException_name(),
1728 vmSymbols::throwable_void_signature(),
1729 uncaught_exception,
1730 THREAD);
1731 if (HAS_PENDING_EXCEPTION) {
1732 ResourceMark rm(this);
1733 jio_fprintf(defaultStream::error_stream(),
1734 "\nException: %s thrown from the UncaughtExceptionHandler"
1735 " in thread \"%s\"\n",
1736 pending_exception()->klass()->external_name(),
1737 get_thread_name());
1738 CLEAR_PENDING_EXCEPTION;
1739 }
1740 }
1741
1742 // Called before the java thread exit since we want to read info
1743 // from java_lang_Thread object
1744 EventThreadEnd event;
1745 if (event.should_commit()) {
1746 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1747 event.commit();
1748 }
1749
1750 // Call after last event on thread
1751 EVENT_THREAD_EXIT(this);
1752
1753 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1754 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1755 // is deprecated anyhow.
1756 if (!is_Compiler_thread()) {
1757 int count = 3;
1758 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1759 EXCEPTION_MARK;
1760 JavaValue result(T_VOID);
1761 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1762 JavaCalls::call_virtual(&result,
1763 threadObj, thread_klass,
1764 vmSymbols::exit_method_name(),
1765 vmSymbols::void_method_signature(),
1766 THREAD);
1767 CLEAR_PENDING_EXCEPTION;
1768 }
1769 }
1770 // notify JVMTI
1771 if (JvmtiExport::should_post_thread_life()) {
1772 JvmtiExport::post_thread_end(this);
1773 }
1774
1775 // We have notified the agents that we are exiting, before we go on,
1776 // we must check for a pending external suspend request and honor it
1777 // in order to not surprise the thread that made the suspend request.
1778 while (true) {
1779 {
1780 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1781 if (!is_external_suspend()) {
1782 set_terminated(_thread_exiting);
1783 ThreadService::current_thread_exiting(this);
1784 break;
1785 }
1786 // Implied else:
1787 // Things get a little tricky here. We have a pending external
1788 // suspend request, but we are holding the SR_lock so we
1789 // can't just self-suspend. So we temporarily drop the lock
1790 // and then self-suspend.
1791 }
1792
1793 ThreadBlockInVM tbivm(this);
1794 java_suspend_self();
1795
1796 // We're done with this suspend request, but we have to loop around
1797 // and check again. Eventually we will get SR_lock without a pending
1798 // external suspend request and will be able to mark ourselves as
1799 // exiting.
1800 }
1801 // no more external suspends are allowed at this point
1802 } else {
1803 // before_exit() has already posted JVMTI THREAD_END events
1804 }
1805
1806 // Notify waiters on thread object. This has to be done after exit() is called
1807 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1808 // group should have the destroyed bit set before waiters are notified).
1809 ensure_join(this);
1810 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1811
1812 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1813 // held by this thread must be released. The spec does not distinguish
1814 // between JNI-acquired and regular Java monitors. We can only see
1815 // regular Java monitors here if monitor enter-exit matching is broken.
1816 //
1817 // Optionally release any monitors for regular JavaThread exits. This
1818 // is provided as a work around for any bugs in monitor enter-exit
1819 // matching. This can be expensive so it is not enabled by default.
1820 // ObjectMonitor::Knob_ExitRelease is a superset of the
1821 // JNIDetachReleasesMonitors option.
1822 //
1823 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1824 // ObjectSynchronizer::release_monitors_owned_by_thread().
1825 if ((exit_type == jni_detach && JNIDetachReleasesMonitors) ||
1826 ObjectMonitor::Knob_ExitRelease) {
1827 // Sanity check even though JNI DetachCurrentThread() would have
1828 // returned JNI_ERR if there was a Java frame. JavaThread exit
1829 // should be done executing Java code by the time we get here.
1830 assert(!this->has_last_Java_frame(),
1831 "should not have a Java frame when detaching or exiting");
1832 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1833 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1834 }
1835
1836 // These things needs to be done while we are still a Java Thread. Make sure that thread
1837 // is in a consistent state, in case GC happens
1838 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1839
1840 if (active_handles() != NULL) {
1841 JNIHandleBlock* block = active_handles();
1842 set_active_handles(NULL);
1843 JNIHandleBlock::release_block(block);
1844 }
1845
1846 if (free_handle_block() != NULL) {
1847 JNIHandleBlock* block = free_handle_block();
1848 set_free_handle_block(NULL);
1849 JNIHandleBlock::release_block(block);
1850 }
1851
1852 // These have to be removed while this is still a valid thread.
1853 remove_stack_guard_pages();
1854
1855 if (UseTLAB) {
1856 tlab().make_parsable(true); // retire TLAB
1857 }
1858
1859 if (JvmtiEnv::environments_might_exist()) {
1860 JvmtiExport::cleanup_thread(this);
1861 }
1862
1863 // We must flush any deferred card marks before removing a thread from
1864 // the list of active threads.
1865 Universe::heap()->flush_deferred_store_barrier(this);
1866 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1867
1868 #if INCLUDE_ALL_GCS
1869 // We must flush the G1-related buffers before removing a thread
1870 // from the list of active threads. We must do this after any deferred
1871 // card marks have been flushed (above) so that any entries that are
1872 // added to the thread's dirty card queue as a result are not lost.
1873 if (UseG1GC || UseShenandoahGC) {
1874 flush_barrier_queues();
1875 }
1876 if (UseShenandoahGC && UseTLAB) {
1877 gclab().make_parsable(true);
1878 }
1879 #endif // INCLUDE_ALL_GCS
1880
1881 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1882 Threads::remove(this);
1883 }
1884
1885 #if INCLUDE_ALL_GCS
1886 // Flush G1-related queues.
1887 void JavaThread::flush_barrier_queues() {
1888 satb_mark_queue().flush();
1889 dirty_card_queue().flush();
1890 }
1891
1892 void JavaThread::initialize_queues() {
1893 assert(!SafepointSynchronize::is_at_safepoint(),
1894 "we should not be at a safepoint");
1895
1896 ObjPtrQueue& satb_queue = satb_mark_queue();
1897 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1898 // The SATB queue should have been constructed with its active
1899 // field set to false.
1900 assert(!satb_queue.is_active(), "SATB queue should not be active");
1901 assert(satb_queue.is_empty(), "SATB queue should be empty");
1902 // If we are creating the thread during a marking cycle, we should
1903 // set the active field of the SATB queue to true.
1904 if (satb_queue_set.is_active()) {
1905 satb_queue.set_active(true);
1906 }
1907
1908 DirtyCardQueue& dirty_queue = dirty_card_queue();
1909 // The dirty card queue should have been constructed with its
1910 // active field set to true.
1911 assert(dirty_queue.is_active(), "dirty card queue should be active");
1912 }
1913
1914 bool JavaThread::evacuation_in_progress() const {
1915 return _evacuation_in_progress;
1916 }
1917
1918 void JavaThread::set_evacuation_in_progress(bool in_prog) {
1919 _evacuation_in_progress = in_prog;
1920 }
1921
1922 void JavaThread::set_evacuation_in_progress_all_threads(bool in_prog) {
1923 _evacuation_in_progress_global = in_prog;
1924 for (JavaThread* t = Threads::first(); t; t = t->next()) {
1925 t->set_evacuation_in_progress(in_prog);
1926 }
1927 }
1928 #endif // INCLUDE_ALL_GCS
1929
1930 void JavaThread::cleanup_failed_attach_current_thread() {
1931 if (get_thread_profiler() != NULL) {
1932 get_thread_profiler()->disengage();
1933 ResourceMark rm;
1934 get_thread_profiler()->print(get_thread_name());
1935 }
1936
1937 if (active_handles() != NULL) {
1938 JNIHandleBlock* block = active_handles();
1939 set_active_handles(NULL);
1940 JNIHandleBlock::release_block(block);
1941 }
1942
1943 if (free_handle_block() != NULL) {
1944 JNIHandleBlock* block = free_handle_block();
1945 set_free_handle_block(NULL);
1946 JNIHandleBlock::release_block(block);
1947 }
1948
1949 // These have to be removed while this is still a valid thread.
1950 remove_stack_guard_pages();
1951
1952 if (UseTLAB) {
1953 tlab().make_parsable(true); // retire TLAB, if any
1954 }
1955
1956 #if INCLUDE_ALL_GCS
1957 if (UseG1GC || UseShenandoahGC) {
1958 flush_barrier_queues();
1959 }
1960 if (UseShenandoahGC && UseTLAB) {
1961 gclab().make_parsable(true);
1962 }
1963 #endif // INCLUDE_ALL_GCS
1964
1965 Threads::remove(this);
1966 delete this;
1967 }
1968
1969
1970
1971
1972 JavaThread* JavaThread::active() {
1973 Thread* thread = ThreadLocalStorage::thread();
1974 assert(thread != NULL, "just checking");
1975 if (thread->is_Java_thread()) {
1976 return (JavaThread*) thread;
1977 } else {
1978 assert(thread->is_VM_thread(), "this must be a vm thread");
1979 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1980 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1981 assert(ret->is_Java_thread(), "must be a Java thread");
1982 return ret;
1983 }
1984 }
1985
1986 bool JavaThread::is_lock_owned(address adr) const {
1987 if (Thread::is_lock_owned(adr)) return true;
1988
1989 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1990 if (chunk->contains(adr)) return true;
1991 }
1992
1993 return false;
1994 }
1995
1996
1997 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1998 chunk->set_next(monitor_chunks());
1999 set_monitor_chunks(chunk);
2000 }
2001
2002 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2003 guarantee(monitor_chunks() != NULL, "must be non empty");
2004 if (monitor_chunks() == chunk) {
2005 set_monitor_chunks(chunk->next());
2006 } else {
2007 MonitorChunk* prev = monitor_chunks();
2008 while (prev->next() != chunk) prev = prev->next();
2009 prev->set_next(chunk->next());
2010 }
2011 }
2012
2013 // JVM support.
2014
2015 // Note: this function shouldn't block if it's called in
2016 // _thread_in_native_trans state (such as from
2017 // check_special_condition_for_native_trans()).
2018 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2019
2020 if (has_last_Java_frame() && has_async_condition()) {
2021 // If we are at a polling page safepoint (not a poll return)
2022 // then we must defer async exception because live registers
2023 // will be clobbered by the exception path. Poll return is
2024 // ok because the call we a returning from already collides
2025 // with exception handling registers and so there is no issue.
2026 // (The exception handling path kills call result registers but
2027 // this is ok since the exception kills the result anyway).
2028
2029 if (is_at_poll_safepoint()) {
2030 // if the code we are returning to has deoptimized we must defer
2031 // the exception otherwise live registers get clobbered on the
2032 // exception path before deoptimization is able to retrieve them.
2033 //
2034 RegisterMap map(this, false);
2035 frame caller_fr = last_frame().sender(&map);
2036 assert(caller_fr.is_compiled_frame(), "what?");
2037 if (caller_fr.is_deoptimized_frame()) {
2038 if (TraceExceptions) {
2039 ResourceMark rm;
2040 tty->print_cr("deferred async exception at compiled safepoint");
2041 }
2042 return;
2043 }
2044 }
2045 }
2046
2047 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2048 if (condition == _no_async_condition) {
2049 // Conditions have changed since has_special_runtime_exit_condition()
2050 // was called:
2051 // - if we were here only because of an external suspend request,
2052 // then that was taken care of above (or cancelled) so we are done
2053 // - if we were here because of another async request, then it has
2054 // been cleared between the has_special_runtime_exit_condition()
2055 // and now so again we are done
2056 return;
2057 }
2058
2059 // Check for pending async. exception
2060 if (_pending_async_exception != NULL) {
2061 // Only overwrite an already pending exception, if it is not a threadDeath.
2062 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2063
2064 // We cannot call Exceptions::_throw(...) here because we cannot block
2065 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2066
2067 if (TraceExceptions) {
2068 ResourceMark rm;
2069 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2070 if (has_last_Java_frame()) {
2071 frame f = last_frame();
2072 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2073 }
2074 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2075 }
2076 _pending_async_exception = NULL;
2077 clear_has_async_exception();
2078 }
2079 }
2080
2081 if (check_unsafe_error &&
2082 condition == _async_unsafe_access_error && !has_pending_exception()) {
2083 condition = _no_async_condition; // done
2084 switch (thread_state()) {
2085 case _thread_in_vm: {
2086 JavaThread* THREAD = this;
2087 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2088 }
2089 case _thread_in_native: {
2090 ThreadInVMfromNative tiv(this);
2091 JavaThread* THREAD = this;
2092 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2093 }
2094 case _thread_in_Java: {
2095 ThreadInVMfromJava tiv(this);
2096 JavaThread* THREAD = this;
2097 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2098 }
2099 default:
2100 ShouldNotReachHere();
2101 }
2102 }
2103
2104 assert(condition == _no_async_condition || has_pending_exception() ||
2105 (!check_unsafe_error && condition == _async_unsafe_access_error),
2106 "must have handled the async condition, if no exception");
2107 }
2108
2109 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2110 //
2111 // Check for pending external suspend. Internal suspend requests do
2112 // not use handle_special_runtime_exit_condition().
2113 // If JNIEnv proxies are allowed, don't self-suspend if the target
2114 // thread is not the current thread. In older versions of jdbx, jdbx
2115 // threads could call into the VM with another thread's JNIEnv so we
2116 // can be here operating on behalf of a suspended thread (4432884).
2117 bool do_self_suspend = is_external_suspend_with_lock();
2118 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2119 //
2120 // Because thread is external suspended the safepoint code will count
2121 // thread as at a safepoint. This can be odd because we can be here
2122 // as _thread_in_Java which would normally transition to _thread_blocked
2123 // at a safepoint. We would like to mark the thread as _thread_blocked
2124 // before calling java_suspend_self like all other callers of it but
2125 // we must then observe proper safepoint protocol. (We can't leave
2126 // _thread_blocked with a safepoint in progress). However we can be
2127 // here as _thread_in_native_trans so we can't use a normal transition
2128 // constructor/destructor pair because they assert on that type of
2129 // transition. We could do something like:
2130 //
2131 // JavaThreadState state = thread_state();
2132 // set_thread_state(_thread_in_vm);
2133 // {
2134 // ThreadBlockInVM tbivm(this);
2135 // java_suspend_self()
2136 // }
2137 // set_thread_state(_thread_in_vm_trans);
2138 // if (safepoint) block;
2139 // set_thread_state(state);
2140 //
2141 // but that is pretty messy. Instead we just go with the way the
2142 // code has worked before and note that this is the only path to
2143 // java_suspend_self that doesn't put the thread in _thread_blocked
2144 // mode.
2145
2146 frame_anchor()->make_walkable(this);
2147 java_suspend_self();
2148
2149 // We might be here for reasons in addition to the self-suspend request
2150 // so check for other async requests.
2151 }
2152
2153 if (check_asyncs) {
2154 check_and_handle_async_exceptions();
2155 }
2156 }
2157
2158 void JavaThread::send_thread_stop(oop java_throwable) {
2159 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2160 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2161 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2162
2163 // Do not throw asynchronous exceptions against the compiler thread
2164 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2165 if (is_Compiler_thread()) return;
2166
2167 {
2168 // Actually throw the Throwable against the target Thread - however
2169 // only if there is no thread death exception installed already.
2170 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2171 // If the topmost frame is a runtime stub, then we are calling into
2172 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2173 // must deoptimize the caller before continuing, as the compiled exception handler table
2174 // may not be valid
2175 if (has_last_Java_frame()) {
2176 frame f = last_frame();
2177 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2178 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2179 RegisterMap reg_map(this, UseBiasedLocking);
2180 frame compiled_frame = f.sender(®_map);
2181 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2182 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2183 }
2184 }
2185 }
2186
2187 // Set async. pending exception in thread.
2188 set_pending_async_exception(java_throwable);
2189
2190 if (TraceExceptions) {
2191 ResourceMark rm;
2192 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2193 }
2194 // for AbortVMOnException flag
2195 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2196 }
2197 }
2198
2199
2200 // Interrupt thread so it will wake up from a potential wait()
2201 Thread::interrupt(this);
2202 }
2203
2204 // External suspension mechanism.
2205 //
2206 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2207 // to any VM_locks and it is at a transition
2208 // Self-suspension will happen on the transition out of the vm.
2209 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2210 //
2211 // Guarantees on return:
2212 // + Target thread will not execute any new bytecode (that's why we need to
2213 // force a safepoint)
2214 // + Target thread will not enter any new monitors
2215 //
2216 void JavaThread::java_suspend() {
2217 { MutexLocker mu(Threads_lock);
2218 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2219 return;
2220 }
2221 }
2222
2223 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2224 if (!is_external_suspend()) {
2225 // a racing resume has cancelled us; bail out now
2226 return;
2227 }
2228
2229 // suspend is done
2230 uint32_t debug_bits = 0;
2231 // Warning: is_ext_suspend_completed() may temporarily drop the
2232 // SR_lock to allow the thread to reach a stable thread state if
2233 // it is currently in a transient thread state.
2234 if (is_ext_suspend_completed(false /* !called_by_wait */,
2235 SuspendRetryDelay, &debug_bits)) {
2236 return;
2237 }
2238 }
2239
2240 VM_ForceSafepoint vm_suspend;
2241 VMThread::execute(&vm_suspend);
2242 }
2243
2244 // Part II of external suspension.
2245 // A JavaThread self suspends when it detects a pending external suspend
2246 // request. This is usually on transitions. It is also done in places
2247 // where continuing to the next transition would surprise the caller,
2248 // e.g., monitor entry.
2249 //
2250 // Returns the number of times that the thread self-suspended.
2251 //
2252 // Note: DO NOT call java_suspend_self() when you just want to block current
2253 // thread. java_suspend_self() is the second stage of cooperative
2254 // suspension for external suspend requests and should only be used
2255 // to complete an external suspend request.
2256 //
2257 int JavaThread::java_suspend_self() {
2258 int ret = 0;
2259
2260 // we are in the process of exiting so don't suspend
2261 if (is_exiting()) {
2262 clear_external_suspend();
2263 return ret;
2264 }
2265
2266 assert(_anchor.walkable() ||
2267 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2268 "must have walkable stack");
2269
2270 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2271
2272 assert(!this->is_ext_suspended(),
2273 "a thread trying to self-suspend should not already be suspended");
2274
2275 if (this->is_suspend_equivalent()) {
2276 // If we are self-suspending as a result of the lifting of a
2277 // suspend equivalent condition, then the suspend_equivalent
2278 // flag is not cleared until we set the ext_suspended flag so
2279 // that wait_for_ext_suspend_completion() returns consistent
2280 // results.
2281 this->clear_suspend_equivalent();
2282 }
2283
2284 // A racing resume may have cancelled us before we grabbed SR_lock
2285 // above. Or another external suspend request could be waiting for us
2286 // by the time we return from SR_lock()->wait(). The thread
2287 // that requested the suspension may already be trying to walk our
2288 // stack and if we return now, we can change the stack out from under
2289 // it. This would be a "bad thing (TM)" and cause the stack walker
2290 // to crash. We stay self-suspended until there are no more pending
2291 // external suspend requests.
2292 while (is_external_suspend()) {
2293 ret++;
2294 this->set_ext_suspended();
2295
2296 // _ext_suspended flag is cleared by java_resume()
2297 while (is_ext_suspended()) {
2298 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2299 }
2300 }
2301
2302 return ret;
2303 }
2304
2305 #ifdef ASSERT
2306 // verify the JavaThread has not yet been published in the Threads::list, and
2307 // hence doesn't need protection from concurrent access at this stage
2308 void JavaThread::verify_not_published() {
2309 if (!Threads_lock->owned_by_self()) {
2310 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2311 assert(!Threads::includes(this),
2312 "java thread shouldn't have been published yet!");
2313 } else {
2314 assert(!Threads::includes(this),
2315 "java thread shouldn't have been published yet!");
2316 }
2317 }
2318 #endif
2319
2320 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2321 // progress or when _suspend_flags is non-zero.
2322 // Current thread needs to self-suspend if there is a suspend request and/or
2323 // block if a safepoint is in progress.
2324 // Async exception ISN'T checked.
2325 // Note only the ThreadInVMfromNative transition can call this function
2326 // directly and when thread state is _thread_in_native_trans
2327 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2328 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2329
2330 JavaThread *curJT = JavaThread::current();
2331 bool do_self_suspend = thread->is_external_suspend();
2332
2333 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2334
2335 // If JNIEnv proxies are allowed, don't self-suspend if the target
2336 // thread is not the current thread. In older versions of jdbx, jdbx
2337 // threads could call into the VM with another thread's JNIEnv so we
2338 // can be here operating on behalf of a suspended thread (4432884).
2339 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2340 JavaThreadState state = thread->thread_state();
2341
2342 // We mark this thread_blocked state as a suspend-equivalent so
2343 // that a caller to is_ext_suspend_completed() won't be confused.
2344 // The suspend-equivalent state is cleared by java_suspend_self().
2345 thread->set_suspend_equivalent();
2346
2347 // If the safepoint code sees the _thread_in_native_trans state, it will
2348 // wait until the thread changes to other thread state. There is no
2349 // guarantee on how soon we can obtain the SR_lock and complete the
2350 // self-suspend request. It would be a bad idea to let safepoint wait for
2351 // too long. Temporarily change the state to _thread_blocked to
2352 // let the VM thread know that this thread is ready for GC. The problem
2353 // of changing thread state is that safepoint could happen just after
2354 // java_suspend_self() returns after being resumed, and VM thread will
2355 // see the _thread_blocked state. We must check for safepoint
2356 // after restoring the state and make sure we won't leave while a safepoint
2357 // is in progress.
2358 thread->set_thread_state(_thread_blocked);
2359 thread->java_suspend_self();
2360 thread->set_thread_state(state);
2361 // Make sure new state is seen by VM thread
2362 if (os::is_MP()) {
2363 if (UseMembar) {
2364 // Force a fence between the write above and read below
2365 OrderAccess::fence();
2366 } else {
2367 // Must use this rather than serialization page in particular on Windows
2368 InterfaceSupport::serialize_memory(thread);
2369 }
2370 }
2371 }
2372
2373 if (SafepointSynchronize::do_call_back()) {
2374 // If we are safepointing, then block the caller which may not be
2375 // the same as the target thread (see above).
2376 SafepointSynchronize::block(curJT);
2377 }
2378
2379 if (thread->is_deopt_suspend()) {
2380 thread->clear_deopt_suspend();
2381 RegisterMap map(thread, false);
2382 frame f = thread->last_frame();
2383 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2384 f = f.sender(&map);
2385 }
2386 if (f.id() == thread->must_deopt_id()) {
2387 thread->clear_must_deopt_id();
2388 f.deoptimize(thread);
2389 } else {
2390 fatal("missed deoptimization!");
2391 }
2392 }
2393 }
2394
2395 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2396 // progress or when _suspend_flags is non-zero.
2397 // Current thread needs to self-suspend if there is a suspend request and/or
2398 // block if a safepoint is in progress.
2399 // Also check for pending async exception (not including unsafe access error).
2400 // Note only the native==>VM/Java barriers can call this function and when
2401 // thread state is _thread_in_native_trans.
2402 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2403 check_safepoint_and_suspend_for_native_trans(thread);
2404
2405 if (thread->has_async_exception()) {
2406 // We are in _thread_in_native_trans state, don't handle unsafe
2407 // access error since that may block.
2408 thread->check_and_handle_async_exceptions(false);
2409 }
2410 }
2411
2412 // This is a variant of the normal
2413 // check_special_condition_for_native_trans with slightly different
2414 // semantics for use by critical native wrappers. It does all the
2415 // normal checks but also performs the transition back into
2416 // thread_in_Java state. This is required so that critical natives
2417 // can potentially block and perform a GC if they are the last thread
2418 // exiting the GC_locker.
2419 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2420 check_special_condition_for_native_trans(thread);
2421
2422 // Finish the transition
2423 thread->set_thread_state(_thread_in_Java);
2424
2425 if (thread->do_critical_native_unlock()) {
2426 ThreadInVMfromJavaNoAsyncException tiv(thread);
2427 GC_locker::unlock_critical(thread);
2428 thread->clear_critical_native_unlock();
2429 }
2430 }
2431
2432 // We need to guarantee the Threads_lock here, since resumes are not
2433 // allowed during safepoint synchronization
2434 // Can only resume from an external suspension
2435 void JavaThread::java_resume() {
2436 assert_locked_or_safepoint(Threads_lock);
2437
2438 // Sanity check: thread is gone, has started exiting or the thread
2439 // was not externally suspended.
2440 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2441 return;
2442 }
2443
2444 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2445
2446 clear_external_suspend();
2447
2448 if (is_ext_suspended()) {
2449 clear_ext_suspended();
2450 SR_lock()->notify_all();
2451 }
2452 }
2453
2454 void JavaThread::create_stack_guard_pages() {
2455 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2456 address low_addr = stack_base() - stack_size();
2457 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2458
2459 int allocate = os::allocate_stack_guard_pages();
2460 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2461
2462 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2463 warning("Attempt to allocate stack guard pages failed.");
2464 return;
2465 }
2466
2467 if (os::guard_memory((char *) low_addr, len)) {
2468 _stack_guard_state = stack_guard_enabled;
2469 } else {
2470 warning("Attempt to protect stack guard pages failed.");
2471 if (os::uncommit_memory((char *) low_addr, len)) {
2472 warning("Attempt to deallocate stack guard pages failed.");
2473 }
2474 }
2475 }
2476
2477 void JavaThread::remove_stack_guard_pages() {
2478 assert(Thread::current() == this, "from different thread");
2479 if (_stack_guard_state == stack_guard_unused) return;
2480 address low_addr = stack_base() - stack_size();
2481 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2482
2483 if (os::allocate_stack_guard_pages()) {
2484 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2485 _stack_guard_state = stack_guard_unused;
2486 } else {
2487 warning("Attempt to deallocate stack guard pages failed.");
2488 }
2489 } else {
2490 if (_stack_guard_state == stack_guard_unused) return;
2491 if (os::unguard_memory((char *) low_addr, len)) {
2492 _stack_guard_state = stack_guard_unused;
2493 } else {
2494 warning("Attempt to unprotect stack guard pages failed.");
2495 }
2496 }
2497 }
2498
2499 void JavaThread::enable_stack_yellow_zone() {
2500 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2501 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2502
2503 // The base notation is from the stacks point of view, growing downward.
2504 // We need to adjust it to work correctly with guard_memory()
2505 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2506
2507 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2508 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2509
2510 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2511 _stack_guard_state = stack_guard_enabled;
2512 } else {
2513 warning("Attempt to guard stack yellow zone failed.");
2514 }
2515 enable_register_stack_guard();
2516 }
2517
2518 void JavaThread::disable_stack_yellow_zone() {
2519 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2520 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2521
2522 // Simply return if called for a thread that does not use guard pages.
2523 if (_stack_guard_state == stack_guard_unused) return;
2524
2525 // The base notation is from the stacks point of view, growing downward.
2526 // We need to adjust it to work correctly with guard_memory()
2527 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2528
2529 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2530 _stack_guard_state = stack_guard_yellow_disabled;
2531 } else {
2532 warning("Attempt to unguard stack yellow zone failed.");
2533 }
2534 disable_register_stack_guard();
2535 }
2536
2537 void JavaThread::enable_stack_red_zone() {
2538 // The base notation is from the stacks point of view, growing downward.
2539 // We need to adjust it to work correctly with guard_memory()
2540 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2541 address base = stack_red_zone_base() - stack_red_zone_size();
2542
2543 guarantee(base < stack_base(), "Error calculating stack red zone");
2544 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2545
2546 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2547 warning("Attempt to guard stack red zone failed.");
2548 }
2549 }
2550
2551 void JavaThread::disable_stack_red_zone() {
2552 // The base notation is from the stacks point of view, growing downward.
2553 // We need to adjust it to work correctly with guard_memory()
2554 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2555 address base = stack_red_zone_base() - stack_red_zone_size();
2556 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2557 warning("Attempt to unguard stack red zone failed.");
2558 }
2559 }
2560
2561 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2562 // ignore is there is no stack
2563 if (!has_last_Java_frame()) return;
2564 // traverse the stack frames. Starts from top frame.
2565 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2566 frame* fr = fst.current();
2567 f(fr, fst.register_map());
2568 }
2569 }
2570
2571
2572 #ifndef PRODUCT
2573 // Deoptimization
2574 // Function for testing deoptimization
2575 void JavaThread::deoptimize() {
2576 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2577 StackFrameStream fst(this, UseBiasedLocking);
2578 bool deopt = false; // Dump stack only if a deopt actually happens.
2579 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2580 // Iterate over all frames in the thread and deoptimize
2581 for (; !fst.is_done(); fst.next()) {
2582 if (fst.current()->can_be_deoptimized()) {
2583
2584 if (only_at) {
2585 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2586 // consists of comma or carriage return separated numbers so
2587 // search for the current bci in that string.
2588 address pc = fst.current()->pc();
2589 nmethod* nm = (nmethod*) fst.current()->cb();
2590 ScopeDesc* sd = nm->scope_desc_at(pc);
2591 char buffer[8];
2592 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2593 size_t len = strlen(buffer);
2594 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2595 while (found != NULL) {
2596 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2597 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2598 // Check that the bci found is bracketed by terminators.
2599 break;
2600 }
2601 found = strstr(found + 1, buffer);
2602 }
2603 if (!found) {
2604 continue;
2605 }
2606 }
2607
2608 if (DebugDeoptimization && !deopt) {
2609 deopt = true; // One-time only print before deopt
2610 tty->print_cr("[BEFORE Deoptimization]");
2611 trace_frames();
2612 trace_stack();
2613 }
2614 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2615 }
2616 }
2617
2618 if (DebugDeoptimization && deopt) {
2619 tty->print_cr("[AFTER Deoptimization]");
2620 trace_frames();
2621 }
2622 }
2623
2624
2625 // Make zombies
2626 void JavaThread::make_zombies() {
2627 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2628 if (fst.current()->can_be_deoptimized()) {
2629 // it is a Java nmethod
2630 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2631 nm->make_not_entrant();
2632 }
2633 }
2634 }
2635 #endif // PRODUCT
2636
2637
2638 void JavaThread::deoptimized_wrt_marked_nmethods() {
2639 if (!has_last_Java_frame()) return;
2640 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2641 StackFrameStream fst(this, UseBiasedLocking);
2642 for (; !fst.is_done(); fst.next()) {
2643 if (fst.current()->should_be_deoptimized()) {
2644 if (LogCompilation && xtty != NULL) {
2645 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2646 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2647 this->name(), nm != NULL ? nm->compile_id() : -1);
2648 }
2649
2650 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2651 }
2652 }
2653 }
2654
2655
2656 // If the caller is a NamedThread, then remember, in the current scope,
2657 // the given JavaThread in its _processed_thread field.
2658 class RememberProcessedThread: public StackObj {
2659 NamedThread* _cur_thr;
2660 public:
2661 RememberProcessedThread(JavaThread* jthr) {
2662 Thread* thread = Thread::current();
2663 if (thread->is_Named_thread()) {
2664 _cur_thr = (NamedThread *)thread;
2665 _cur_thr->set_processed_thread(jthr);
2666 } else {
2667 _cur_thr = NULL;
2668 }
2669 }
2670
2671 ~RememberProcessedThread() {
2672 if (_cur_thr) {
2673 _cur_thr->set_processed_thread(NULL);
2674 }
2675 }
2676 };
2677
2678 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2679 // Verify that the deferred card marks have been flushed.
2680 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2681
2682 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2683 // since there may be more than one thread using each ThreadProfiler.
2684
2685 // Traverse the GCHandles
2686 Thread::oops_do(f, cld_f, cf);
2687
2688 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2689 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2690
2691 if (has_last_Java_frame()) {
2692 // Record JavaThread to GC thread
2693 RememberProcessedThread rpt(this);
2694
2695 // Traverse the privileged stack
2696 if (_privileged_stack_top != NULL) {
2697 _privileged_stack_top->oops_do(f);
2698 }
2699
2700 // traverse the registered growable array
2701 if (_array_for_gc != NULL) {
2702 for (int index = 0; index < _array_for_gc->length(); index++) {
2703 f->do_oop(_array_for_gc->adr_at(index));
2704 }
2705 }
2706
2707 // Traverse the monitor chunks
2708 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2709 chunk->oops_do(f);
2710 }
2711
2712 // Traverse the execution stack
2713 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2714 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2715 }
2716 }
2717
2718 // callee_target is never live across a gc point so NULL it here should
2719 // it still contain a methdOop.
2720
2721 set_callee_target(NULL);
2722
2723 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2724 // If we have deferred set_locals there might be oops waiting to be
2725 // written
2726 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2727 if (list != NULL) {
2728 for (int i = 0; i < list->length(); i++) {
2729 list->at(i)->oops_do(f);
2730 }
2731 }
2732
2733 // Traverse instance variables at the end since the GC may be moving things
2734 // around using this function
2735 f->do_oop((oop*) &_threadObj);
2736 f->do_oop((oop*) &_vm_result);
2737 f->do_oop((oop*) &_exception_oop);
2738 f->do_oop((oop*) &_pending_async_exception);
2739
2740 if (jvmti_thread_state() != NULL) {
2741 jvmti_thread_state()->oops_do(f);
2742 }
2743 }
2744
2745 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2746 Thread::nmethods_do(cf); // (super method is a no-op)
2747
2748 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2749 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2750
2751 if (has_last_Java_frame()) {
2752 // Traverse the execution stack
2753 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2754 fst.current()->nmethods_do(cf);
2755 }
2756 }
2757 }
2758
2759 void JavaThread::metadata_do(void f(Metadata*)) {
2760 if (has_last_Java_frame()) {
2761 // Traverse the execution stack to call f() on the methods in the stack
2762 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2763 fst.current()->metadata_do(f);
2764 }
2765 } else if (is_Compiler_thread()) {
2766 // need to walk ciMetadata in current compile tasks to keep alive.
2767 CompilerThread* ct = (CompilerThread*)this;
2768 if (ct->env() != NULL) {
2769 ct->env()->metadata_do(f);
2770 }
2771 if (ct->task() != NULL) {
2772 ct->task()->metadata_do(f);
2773 }
2774 }
2775 }
2776
2777 // Printing
2778 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2779 switch (_thread_state) {
2780 case _thread_uninitialized: return "_thread_uninitialized";
2781 case _thread_new: return "_thread_new";
2782 case _thread_new_trans: return "_thread_new_trans";
2783 case _thread_in_native: return "_thread_in_native";
2784 case _thread_in_native_trans: return "_thread_in_native_trans";
2785 case _thread_in_vm: return "_thread_in_vm";
2786 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2787 case _thread_in_Java: return "_thread_in_Java";
2788 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2789 case _thread_blocked: return "_thread_blocked";
2790 case _thread_blocked_trans: return "_thread_blocked_trans";
2791 default: return "unknown thread state";
2792 }
2793 }
2794
2795 #ifndef PRODUCT
2796 void JavaThread::print_thread_state_on(outputStream *st) const {
2797 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2798 };
2799 void JavaThread::print_thread_state() const {
2800 print_thread_state_on(tty);
2801 }
2802 #endif // PRODUCT
2803
2804 // Called by Threads::print() for VM_PrintThreads operation
2805 void JavaThread::print_on(outputStream *st) const {
2806 st->print("\"%s\" ", get_thread_name());
2807 oop thread_oop = threadObj();
2808 if (thread_oop != NULL) {
2809 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2810 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2811 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2812 }
2813 Thread::print_on(st);
2814 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2815 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2816 if (thread_oop != NULL) {
2817 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2818 }
2819 #ifndef PRODUCT
2820 print_thread_state_on(st);
2821 _safepoint_state->print_on(st);
2822 #endif // PRODUCT
2823 }
2824
2825 // Called by fatal error handler. The difference between this and
2826 // JavaThread::print() is that we can't grab lock or allocate memory.
2827 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2828 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2829 oop thread_obj = threadObj();
2830 if (thread_obj != NULL) {
2831 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2832 }
2833 st->print(" [");
2834 st->print("%s", _get_thread_state_name(_thread_state));
2835 if (osthread()) {
2836 st->print(", id=%d", osthread()->thread_id());
2837 }
2838 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2839 _stack_base - _stack_size, _stack_base);
2840 st->print("]");
2841 return;
2842 }
2843
2844 // Verification
2845
2846 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2847
2848 void JavaThread::verify() {
2849 // Verify oops in the thread.
2850 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2851
2852 // Verify the stack frames.
2853 frames_do(frame_verify);
2854 }
2855
2856 // CR 6300358 (sub-CR 2137150)
2857 // Most callers of this method assume that it can't return NULL but a
2858 // thread may not have a name whilst it is in the process of attaching to
2859 // the VM - see CR 6412693, and there are places where a JavaThread can be
2860 // seen prior to having it's threadObj set (eg JNI attaching threads and
2861 // if vm exit occurs during initialization). These cases can all be accounted
2862 // for such that this method never returns NULL.
2863 const char* JavaThread::get_thread_name() const {
2864 #ifdef ASSERT
2865 // early safepoints can hit while current thread does not yet have TLS
2866 if (!SafepointSynchronize::is_at_safepoint()) {
2867 Thread *cur = Thread::current();
2868 if (!(cur->is_Java_thread() && cur == this)) {
2869 // Current JavaThreads are allowed to get their own name without
2870 // the Threads_lock.
2871 assert_locked_or_safepoint(Threads_lock);
2872 }
2873 }
2874 #endif // ASSERT
2875 return get_thread_name_string();
2876 }
2877
2878 // Returns a non-NULL representation of this thread's name, or a suitable
2879 // descriptive string if there is no set name
2880 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2881 const char* name_str;
2882 oop thread_obj = threadObj();
2883 if (thread_obj != NULL) {
2884 oop name = java_lang_Thread::name(thread_obj);
2885 if (name != NULL) {
2886 if (buf == NULL) {
2887 name_str = java_lang_String::as_utf8_string(name);
2888 } else {
2889 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2890 }
2891 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2892 name_str = "<no-name - thread is attaching>";
2893 } else {
2894 name_str = Thread::name();
2895 }
2896 } else {
2897 name_str = Thread::name();
2898 }
2899 assert(name_str != NULL, "unexpected NULL thread name");
2900 return name_str;
2901 }
2902
2903
2904 const char* JavaThread::get_threadgroup_name() const {
2905 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2906 oop thread_obj = threadObj();
2907 if (thread_obj != NULL) {
2908 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2909 if (thread_group != NULL) {
2910 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2911 name = typeArrayOop(oopDesc::bs()->read_barrier(name));
2912 // ThreadGroup.name can be null
2913 if (name != NULL) {
2914 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2915 return str;
2916 }
2917 }
2918 }
2919 return NULL;
2920 }
2921
2922 const char* JavaThread::get_parent_name() const {
2923 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2924 oop thread_obj = threadObj();
2925 if (thread_obj != NULL) {
2926 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2927 if (thread_group != NULL) {
2928 oop parent = java_lang_ThreadGroup::parent(thread_group);
2929 if (parent != NULL) {
2930 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2931 name = typeArrayOop(oopDesc::bs()->read_barrier(name));
2932 // ThreadGroup.name can be null
2933 if (name != NULL) {
2934 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2935 return str;
2936 }
2937 }
2938 }
2939 }
2940 return NULL;
2941 }
2942
2943 ThreadPriority JavaThread::java_priority() const {
2944 oop thr_oop = threadObj();
2945 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2946 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2947 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2948 return priority;
2949 }
2950
2951 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2952
2953 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2954 // Link Java Thread object <-> C++ Thread
2955
2956 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2957 // and put it into a new Handle. The Handle "thread_oop" can then
2958 // be used to pass the C++ thread object to other methods.
2959
2960 // Set the Java level thread object (jthread) field of the
2961 // new thread (a JavaThread *) to C++ thread object using the
2962 // "thread_oop" handle.
2963
2964 // Set the thread field (a JavaThread *) of the
2965 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2966
2967 Handle thread_oop(Thread::current(),
2968 JNIHandles::resolve_non_null(jni_thread));
2969 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2970 "must be initialized");
2971 set_threadObj(thread_oop());
2972 java_lang_Thread::set_thread(thread_oop(), this);
2973
2974 if (prio == NoPriority) {
2975 prio = java_lang_Thread::priority(thread_oop());
2976 assert(prio != NoPriority, "A valid priority should be present");
2977 }
2978
2979 // Push the Java priority down to the native thread; needs Threads_lock
2980 Thread::set_priority(this, prio);
2981
2982 prepare_ext();
2983
2984 // Add the new thread to the Threads list and set it in motion.
2985 // We must have threads lock in order to call Threads::add.
2986 // It is crucial that we do not block before the thread is
2987 // added to the Threads list for if a GC happens, then the java_thread oop
2988 // will not be visited by GC.
2989 Threads::add(this);
2990 }
2991
2992 oop JavaThread::current_park_blocker() {
2993 // Support for JSR-166 locks
2994 oop thread_oop = threadObj();
2995 if (thread_oop != NULL &&
2996 JDK_Version::current().supports_thread_park_blocker()) {
2997 return java_lang_Thread::park_blocker(thread_oop);
2998 }
2999 return NULL;
3000 }
3001
3002
3003 void JavaThread::print_stack_on(outputStream* st) {
3004 if (!has_last_Java_frame()) return;
3005 ResourceMark rm;
3006 HandleMark hm;
3007
3008 RegisterMap reg_map(this);
3009 vframe* start_vf = last_java_vframe(®_map);
3010 int count = 0;
3011 for (vframe* f = start_vf; f; f = f->sender()) {
3012 if (f->is_java_frame()) {
3013 javaVFrame* jvf = javaVFrame::cast(f);
3014 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3015
3016 // Print out lock information
3017 if (JavaMonitorsInStackTrace) {
3018 jvf->print_lock_info_on(st, count);
3019 }
3020 } else {
3021 // Ignore non-Java frames
3022 }
3023
3024 // Bail-out case for too deep stacks
3025 count++;
3026 if (MaxJavaStackTraceDepth == count) return;
3027 }
3028 }
3029
3030
3031 // JVMTI PopFrame support
3032 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3033 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3034 if (in_bytes(size_in_bytes) != 0) {
3035 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3036 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3037 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3038 }
3039 }
3040
3041 void* JavaThread::popframe_preserved_args() {
3042 return _popframe_preserved_args;
3043 }
3044
3045 ByteSize JavaThread::popframe_preserved_args_size() {
3046 return in_ByteSize(_popframe_preserved_args_size);
3047 }
3048
3049 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3050 int sz = in_bytes(popframe_preserved_args_size());
3051 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3052 return in_WordSize(sz / wordSize);
3053 }
3054
3055 void JavaThread::popframe_free_preserved_args() {
3056 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3057 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3058 _popframe_preserved_args = NULL;
3059 _popframe_preserved_args_size = 0;
3060 }
3061
3062 #ifndef PRODUCT
3063
3064 void JavaThread::trace_frames() {
3065 tty->print_cr("[Describe stack]");
3066 int frame_no = 1;
3067 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3068 tty->print(" %d. ", frame_no++);
3069 fst.current()->print_value_on(tty, this);
3070 tty->cr();
3071 }
3072 }
3073
3074 class PrintAndVerifyOopClosure: public OopClosure {
3075 protected:
3076 template <class T> inline void do_oop_work(T* p) {
3077 oop obj = oopDesc::load_decode_heap_oop(p);
3078 if (obj == NULL) return;
3079 tty->print(INTPTR_FORMAT ": ", p);
3080 if (obj->is_oop_or_null()) {
3081 if (obj->is_objArray()) {
3082 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3083 } else {
3084 obj->print();
3085 }
3086 } else {
3087 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3088 }
3089 tty->cr();
3090 }
3091 public:
3092 virtual void do_oop(oop* p) { do_oop_work(p); }
3093 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3094 };
3095
3096
3097 static void oops_print(frame* f, const RegisterMap *map) {
3098 PrintAndVerifyOopClosure print;
3099 f->print_value();
3100 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3101 }
3102
3103 // Print our all the locations that contain oops and whether they are
3104 // valid or not. This useful when trying to find the oldest frame
3105 // where an oop has gone bad since the frame walk is from youngest to
3106 // oldest.
3107 void JavaThread::trace_oops() {
3108 tty->print_cr("[Trace oops]");
3109 frames_do(oops_print);
3110 }
3111
3112
3113 #ifdef ASSERT
3114 // Print or validate the layout of stack frames
3115 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3116 ResourceMark rm;
3117 PRESERVE_EXCEPTION_MARK;
3118 FrameValues values;
3119 int frame_no = 0;
3120 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3121 fst.current()->describe(values, ++frame_no);
3122 if (depth == frame_no) break;
3123 }
3124 if (validate_only) {
3125 values.validate();
3126 } else {
3127 tty->print_cr("[Describe stack layout]");
3128 values.print(this);
3129 }
3130 }
3131 #endif
3132
3133 void JavaThread::trace_stack_from(vframe* start_vf) {
3134 ResourceMark rm;
3135 int vframe_no = 1;
3136 for (vframe* f = start_vf; f; f = f->sender()) {
3137 if (f->is_java_frame()) {
3138 javaVFrame::cast(f)->print_activation(vframe_no++);
3139 } else {
3140 f->print();
3141 }
3142 if (vframe_no > StackPrintLimit) {
3143 tty->print_cr("...<more frames>...");
3144 return;
3145 }
3146 }
3147 }
3148
3149
3150 void JavaThread::trace_stack() {
3151 if (!has_last_Java_frame()) return;
3152 ResourceMark rm;
3153 HandleMark hm;
3154 RegisterMap reg_map(this);
3155 trace_stack_from(last_java_vframe(®_map));
3156 }
3157
3158
3159 #endif // PRODUCT
3160
3161
3162 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3163 assert(reg_map != NULL, "a map must be given");
3164 frame f = last_frame();
3165 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3166 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3167 }
3168 return NULL;
3169 }
3170
3171
3172 Klass* JavaThread::security_get_caller_class(int depth) {
3173 vframeStream vfst(this);
3174 vfst.security_get_caller_frame(depth);
3175 if (!vfst.at_end()) {
3176 return vfst.method()->method_holder();
3177 }
3178 return NULL;
3179 }
3180
3181 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3182 assert(thread->is_Compiler_thread(), "must be compiler thread");
3183 CompileBroker::compiler_thread_loop();
3184 }
3185
3186 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3187 NMethodSweeper::sweeper_loop();
3188 }
3189
3190 // Create a CompilerThread
3191 CompilerThread::CompilerThread(CompileQueue* queue,
3192 CompilerCounters* counters)
3193 : JavaThread(&compiler_thread_entry) {
3194 _env = NULL;
3195 _log = NULL;
3196 _task = NULL;
3197 _queue = queue;
3198 _counters = counters;
3199 _buffer_blob = NULL;
3200 _compiler = NULL;
3201
3202 #ifndef PRODUCT
3203 _ideal_graph_printer = NULL;
3204 #endif
3205 }
3206
3207 // Create sweeper thread
3208 CodeCacheSweeperThread::CodeCacheSweeperThread()
3209 : JavaThread(&sweeper_thread_entry) {
3210 _scanned_nmethod = NULL;
3211 }
3212 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3213 JavaThread::oops_do(f, cld_f, cf);
3214 if (_scanned_nmethod != NULL && cf != NULL) {
3215 // Safepoints can occur when the sweeper is scanning an nmethod so
3216 // process it here to make sure it isn't unloaded in the middle of
3217 // a scan.
3218 cf->do_code_blob(_scanned_nmethod);
3219 }
3220 }
3221
3222
3223 // ======= Threads ========
3224
3225 // The Threads class links together all active threads, and provides
3226 // operations over all threads. It is protected by its own Mutex
3227 // lock, which is also used in other contexts to protect thread
3228 // operations from having the thread being operated on from exiting
3229 // and going away unexpectedly (e.g., safepoint synchronization)
3230
3231 JavaThread* Threads::_thread_list = NULL;
3232 int Threads::_number_of_threads = 0;
3233 int Threads::_number_of_non_daemon_threads = 0;
3234 int Threads::_return_code = 0;
3235 int Threads::_thread_claim_parity = 0;
3236 size_t JavaThread::_stack_size_at_create = 0;
3237 #ifdef ASSERT
3238 bool Threads::_vm_complete = false;
3239 #endif
3240
3241 // All JavaThreads
3242 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3243
3244 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3245 void Threads::threads_do(ThreadClosure* tc) {
3246 assert_locked_or_safepoint(Threads_lock);
3247 // ALL_JAVA_THREADS iterates through all JavaThreads
3248 ALL_JAVA_THREADS(p) {
3249 tc->do_thread(p);
3250 }
3251 // Someday we could have a table or list of all non-JavaThreads.
3252 // For now, just manually iterate through them.
3253 tc->do_thread(VMThread::vm_thread());
3254 Universe::heap()->gc_threads_do(tc);
3255 WatcherThread *wt = WatcherThread::watcher_thread();
3256 // Strictly speaking, the following NULL check isn't sufficient to make sure
3257 // the data for WatcherThread is still valid upon being examined. However,
3258 // considering that WatchThread terminates when the VM is on the way to
3259 // exit at safepoint, the chance of the above is extremely small. The right
3260 // way to prevent termination of WatcherThread would be to acquire
3261 // Terminator_lock, but we can't do that without violating the lock rank
3262 // checking in some cases.
3263 if (wt != NULL) {
3264 tc->do_thread(wt);
3265 }
3266
3267 // If CompilerThreads ever become non-JavaThreads, add them here
3268 }
3269
3270 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3271 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3272
3273 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3274 create_vm_init_libraries();
3275 }
3276
3277 initialize_class(vmSymbols::java_lang_String(), CHECK);
3278
3279 // Initialize java_lang.System (needed before creating the thread)
3280 initialize_class(vmSymbols::java_lang_System(), CHECK);
3281 // The VM creates & returns objects of this class. Make sure it's initialized.
3282 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3283 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3284 Handle thread_group = create_initial_thread_group(CHECK);
3285 Universe::set_main_thread_group(thread_group());
3286 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3287 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3288 main_thread->set_threadObj(thread_object);
3289 // Set thread status to running since main thread has
3290 // been started and running.
3291 java_lang_Thread::set_thread_status(thread_object,
3292 java_lang_Thread::RUNNABLE);
3293
3294 // The VM preresolves methods to these classes. Make sure that they get initialized
3295 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3296 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3297 call_initializeSystemClass(CHECK);
3298
3299 // get the Java runtime name after java.lang.System is initialized
3300 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3301 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3302
3303 // an instance of OutOfMemory exception has been allocated earlier
3304 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3305 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3306 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3307 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3308 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3309 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3310 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3311 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3312 }
3313
3314 void Threads::initialize_jsr292_core_classes(TRAPS) {
3315 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3316 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3317 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3318 }
3319
3320 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3321 extern void JDK_Version_init();
3322
3323 // Preinitialize version info.
3324 VM_Version::early_initialize();
3325
3326 // Check version
3327 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3328
3329 // Initialize the output stream module
3330 ostream_init();
3331
3332 // Process java launcher properties.
3333 Arguments::process_sun_java_launcher_properties(args);
3334
3335 // Initialize the os module before using TLS
3336 os::init();
3337
3338 // Initialize system properties.
3339 Arguments::init_system_properties();
3340
3341 // So that JDK version can be used as a discriminator when parsing arguments
3342 JDK_Version_init();
3343
3344 // Update/Initialize System properties after JDK version number is known
3345 Arguments::init_version_specific_system_properties();
3346
3347 // Parse arguments
3348 jint parse_result = Arguments::parse(args);
3349 if (parse_result != JNI_OK) return parse_result;
3350
3351 os::init_before_ergo();
3352
3353 jint ergo_result = Arguments::apply_ergo();
3354 if (ergo_result != JNI_OK) return ergo_result;
3355
3356 // Final check of all ranges after ergonomics which may change values.
3357 if (!CommandLineFlagRangeList::check_ranges()) {
3358 return JNI_EINVAL;
3359 }
3360
3361 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3362 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3363 if (!constraint_result) {
3364 return JNI_EINVAL;
3365 }
3366
3367 if (PauseAtStartup) {
3368 os::pause();
3369 }
3370
3371 HOTSPOT_VM_INIT_BEGIN();
3372
3373 // Record VM creation timing statistics
3374 TraceVmCreationTime create_vm_timer;
3375 create_vm_timer.start();
3376
3377 // Timing (must come after argument parsing)
3378 TraceTime timer("Create VM", TraceStartupTime);
3379
3380 // Initialize the os module after parsing the args
3381 jint os_init_2_result = os::init_2();
3382 if (os_init_2_result != JNI_OK) return os_init_2_result;
3383
3384 jint adjust_after_os_result = Arguments::adjust_after_os();
3385 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3386
3387 // initialize TLS
3388 ThreadLocalStorage::init();
3389
3390 // Initialize output stream logging
3391 ostream_init_log();
3392
3393 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3394 // Must be before create_vm_init_agents()
3395 if (Arguments::init_libraries_at_startup()) {
3396 convert_vm_init_libraries_to_agents();
3397 }
3398
3399 // Launch -agentlib/-agentpath and converted -Xrun agents
3400 if (Arguments::init_agents_at_startup()) {
3401 create_vm_init_agents();
3402 }
3403
3404 // Initialize Threads state
3405 _thread_list = NULL;
3406 _number_of_threads = 0;
3407 _number_of_non_daemon_threads = 0;
3408
3409 // Initialize global data structures and create system classes in heap
3410 vm_init_globals();
3411
3412 // Attach the main thread to this os thread
3413 JavaThread* main_thread = new JavaThread();
3414 main_thread->set_thread_state(_thread_in_vm);
3415 // must do this before set_active_handles and initialize_thread_local_storage
3416 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3417 // change the stack size recorded here to one based on the java thread
3418 // stacksize. This adjusted size is what is used to figure the placement
3419 // of the guard pages.
3420 main_thread->record_stack_base_and_size();
3421 main_thread->initialize_thread_local_storage();
3422
3423 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3424
3425 if (!main_thread->set_as_starting_thread()) {
3426 vm_shutdown_during_initialization(
3427 "Failed necessary internal allocation. Out of swap space");
3428 delete main_thread;
3429 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3430 return JNI_ENOMEM;
3431 }
3432
3433 // Enable guard page *after* os::create_main_thread(), otherwise it would
3434 // crash Linux VM, see notes in os_linux.cpp.
3435 main_thread->create_stack_guard_pages();
3436
3437 // Initialize Java-Level synchronization subsystem
3438 ObjectMonitor::Initialize();
3439
3440 // Initialize global modules
3441 jint status = init_globals();
3442 if (status != JNI_OK) {
3443 delete main_thread;
3444 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3445 return status;
3446 }
3447
3448 // Should be done after the heap is fully created
3449 main_thread->cache_global_variables();
3450
3451 HandleMark hm;
3452
3453 { MutexLocker mu(Threads_lock);
3454 Threads::add(main_thread);
3455 }
3456
3457 // Any JVMTI raw monitors entered in onload will transition into
3458 // real raw monitor. VM is setup enough here for raw monitor enter.
3459 JvmtiExport::transition_pending_onload_raw_monitors();
3460
3461 // Create the VMThread
3462 { TraceTime timer("Start VMThread", TraceStartupTime);
3463 VMThread::create();
3464 Thread* vmthread = VMThread::vm_thread();
3465
3466 if (!os::create_thread(vmthread, os::vm_thread)) {
3467 vm_exit_during_initialization("Cannot create VM thread. "
3468 "Out of system resources.");
3469 }
3470
3471 // Wait for the VM thread to become ready, and VMThread::run to initialize
3472 // Monitors can have spurious returns, must always check another state flag
3473 {
3474 MutexLocker ml(Notify_lock);
3475 os::start_thread(vmthread);
3476 while (vmthread->active_handles() == NULL) {
3477 Notify_lock->wait();
3478 }
3479 }
3480 }
3481
3482 assert(Universe::is_fully_initialized(), "not initialized");
3483 if (VerifyDuringStartup) {
3484 // Make sure we're starting with a clean slate.
3485 VM_Verify verify_op;
3486 VMThread::execute(&verify_op);
3487 }
3488
3489 Thread* THREAD = Thread::current();
3490
3491 // At this point, the Universe is initialized, but we have not executed
3492 // any byte code. Now is a good time (the only time) to dump out the
3493 // internal state of the JVM for sharing.
3494 if (DumpSharedSpaces) {
3495 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3496 ShouldNotReachHere();
3497 }
3498
3499 // Always call even when there are not JVMTI environments yet, since environments
3500 // may be attached late and JVMTI must track phases of VM execution
3501 JvmtiExport::enter_start_phase();
3502
3503 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3504 JvmtiExport::post_vm_start();
3505
3506 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3507
3508 // We need this for ClassDataSharing - the initial vm.info property is set
3509 // with the default value of CDS "sharing" which may be reset through
3510 // command line options.
3511 reset_vm_info_property(CHECK_JNI_ERR);
3512
3513 quicken_jni_functions();
3514
3515 // Must be run after init_ft which initializes ft_enabled
3516 if (TRACE_INITIALIZE() != JNI_OK) {
3517 vm_exit_during_initialization("Failed to initialize tracing backend");
3518 }
3519
3520 // Set flag that basic initialization has completed. Used by exceptions and various
3521 // debug stuff, that does not work until all basic classes have been initialized.
3522 set_init_completed();
3523
3524 Metaspace::post_initialize();
3525
3526 HOTSPOT_VM_INIT_END();
3527
3528 // record VM initialization completion time
3529 #if INCLUDE_MANAGEMENT
3530 Management::record_vm_init_completed();
3531 #endif // INCLUDE_MANAGEMENT
3532
3533 // Compute system loader. Note that this has to occur after set_init_completed, since
3534 // valid exceptions may be thrown in the process.
3535 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3536 // set_init_completed has just been called, causing exceptions not to be shortcut
3537 // anymore. We call vm_exit_during_initialization directly instead.
3538 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3539
3540 #if INCLUDE_ALL_GCS
3541 // Support for ConcurrentMarkSweep. This should be cleaned up
3542 // and better encapsulated. The ugly nested if test would go away
3543 // once things are properly refactored. XXX YSR
3544 if (UseConcMarkSweepGC || UseG1GC || UseShenandoahGC) {
3545 if (UseConcMarkSweepGC) {
3546 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3547 } else if (UseShenandoahGC) {
3548 ShenandoahConcurrentThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3549 } else {
3550 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3551 }
3552 }
3553 #endif // INCLUDE_ALL_GCS
3554
3555 // Always call even when there are not JVMTI environments yet, since environments
3556 // may be attached late and JVMTI must track phases of VM execution
3557 JvmtiExport::enter_live_phase();
3558
3559 // Signal Dispatcher needs to be started before VMInit event is posted
3560 os::signal_init();
3561
3562 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3563 if (!DisableAttachMechanism) {
3564 AttachListener::vm_start();
3565 if (StartAttachListener || AttachListener::init_at_startup()) {
3566 AttachListener::init();
3567 }
3568 }
3569
3570 // Launch -Xrun agents
3571 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3572 // back-end can launch with -Xdebug -Xrunjdwp.
3573 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3574 create_vm_init_libraries();
3575 }
3576
3577 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3578 JvmtiExport::post_vm_initialized();
3579
3580 if (TRACE_START() != JNI_OK) {
3581 vm_exit_during_initialization("Failed to start tracing backend.");
3582 }
3583
3584 if (CleanChunkPoolAsync) {
3585 Chunk::start_chunk_pool_cleaner_task();
3586 }
3587
3588 // initialize compiler(s)
3589 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3590 CompileBroker::compilation_init();
3591 #endif
3592
3593 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3594 // It is done after compilers are initialized, because otherwise compilations of
3595 // signature polymorphic MH intrinsics can be missed
3596 // (see SystemDictionary::find_method_handle_intrinsic).
3597 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3598
3599 #if INCLUDE_MANAGEMENT
3600 Management::initialize(THREAD);
3601
3602 if (HAS_PENDING_EXCEPTION) {
3603 // management agent fails to start possibly due to
3604 // configuration problem and is responsible for printing
3605 // stack trace if appropriate. Simply exit VM.
3606 vm_exit(1);
3607 }
3608 #endif // INCLUDE_MANAGEMENT
3609
3610 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3611 if (MemProfiling) MemProfiler::engage();
3612 StatSampler::engage();
3613 if (CheckJNICalls) JniPeriodicChecker::engage();
3614
3615 BiasedLocking::init();
3616
3617 #if INCLUDE_RTM_OPT
3618 RTMLockingCounters::init();
3619 #endif
3620
3621 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3622 call_postVMInitHook(THREAD);
3623 // The Java side of PostVMInitHook.run must deal with all
3624 // exceptions and provide means of diagnosis.
3625 if (HAS_PENDING_EXCEPTION) {
3626 CLEAR_PENDING_EXCEPTION;
3627 }
3628 }
3629
3630 {
3631 MutexLocker ml(PeriodicTask_lock);
3632 // Make sure the WatcherThread can be started by WatcherThread::start()
3633 // or by dynamic enrollment.
3634 WatcherThread::make_startable();
3635 // Start up the WatcherThread if there are any periodic tasks
3636 // NOTE: All PeriodicTasks should be registered by now. If they
3637 // aren't, late joiners might appear to start slowly (we might
3638 // take a while to process their first tick).
3639 if (PeriodicTask::num_tasks() > 0) {
3640 WatcherThread::start();
3641 }
3642 }
3643
3644 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3645
3646 create_vm_timer.end();
3647 #ifdef ASSERT
3648 _vm_complete = true;
3649 #endif
3650 return JNI_OK;
3651 }
3652
3653 // type for the Agent_OnLoad and JVM_OnLoad entry points
3654 extern "C" {
3655 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3656 }
3657 // Find a command line agent library and return its entry point for
3658 // -agentlib: -agentpath: -Xrun
3659 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3660 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3661 const char *on_load_symbols[],
3662 size_t num_symbol_entries) {
3663 OnLoadEntry_t on_load_entry = NULL;
3664 void *library = NULL;
3665
3666 if (!agent->valid()) {
3667 char buffer[JVM_MAXPATHLEN];
3668 char ebuf[1024] = "";
3669 const char *name = agent->name();
3670 const char *msg = "Could not find agent library ";
3671
3672 // First check to see if agent is statically linked into executable
3673 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3674 library = agent->os_lib();
3675 } else if (agent->is_absolute_path()) {
3676 library = os::dll_load(name, ebuf, sizeof ebuf);
3677 if (library == NULL) {
3678 const char *sub_msg = " in absolute path, with error: ";
3679 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3680 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3681 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3682 // If we can't find the agent, exit.
3683 vm_exit_during_initialization(buf, NULL);
3684 FREE_C_HEAP_ARRAY(char, buf);
3685 }
3686 } else {
3687 // Try to load the agent from the standard dll directory
3688 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3689 name)) {
3690 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3691 }
3692 if (library == NULL) { // Try the local directory
3693 char ns[1] = {0};
3694 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3695 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3696 }
3697 if (library == NULL) {
3698 const char *sub_msg = " on the library path, with error: ";
3699 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3700 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3701 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3702 // If we can't find the agent, exit.
3703 vm_exit_during_initialization(buf, NULL);
3704 FREE_C_HEAP_ARRAY(char, buf);
3705 }
3706 }
3707 }
3708 agent->set_os_lib(library);
3709 agent->set_valid();
3710 }
3711
3712 // Find the OnLoad function.
3713 on_load_entry =
3714 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3715 false,
3716 on_load_symbols,
3717 num_symbol_entries));
3718 return on_load_entry;
3719 }
3720
3721 // Find the JVM_OnLoad entry point
3722 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3723 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3724 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3725 }
3726
3727 // Find the Agent_OnLoad entry point
3728 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3729 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3730 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3731 }
3732
3733 // For backwards compatibility with -Xrun
3734 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3735 // treated like -agentpath:
3736 // Must be called before agent libraries are created
3737 void Threads::convert_vm_init_libraries_to_agents() {
3738 AgentLibrary* agent;
3739 AgentLibrary* next;
3740
3741 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3742 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3743 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3744
3745 // If there is an JVM_OnLoad function it will get called later,
3746 // otherwise see if there is an Agent_OnLoad
3747 if (on_load_entry == NULL) {
3748 on_load_entry = lookup_agent_on_load(agent);
3749 if (on_load_entry != NULL) {
3750 // switch it to the agent list -- so that Agent_OnLoad will be called,
3751 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3752 Arguments::convert_library_to_agent(agent);
3753 } else {
3754 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3755 }
3756 }
3757 }
3758 }
3759
3760 // Create agents for -agentlib: -agentpath: and converted -Xrun
3761 // Invokes Agent_OnLoad
3762 // Called very early -- before JavaThreads exist
3763 void Threads::create_vm_init_agents() {
3764 extern struct JavaVM_ main_vm;
3765 AgentLibrary* agent;
3766
3767 JvmtiExport::enter_onload_phase();
3768
3769 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3770 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3771
3772 if (on_load_entry != NULL) {
3773 // Invoke the Agent_OnLoad function
3774 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3775 if (err != JNI_OK) {
3776 vm_exit_during_initialization("agent library failed to init", agent->name());
3777 }
3778 } else {
3779 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3780 }
3781 }
3782 JvmtiExport::enter_primordial_phase();
3783 }
3784
3785 extern "C" {
3786 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3787 }
3788
3789 void Threads::shutdown_vm_agents() {
3790 // Send any Agent_OnUnload notifications
3791 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3792 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3793 extern struct JavaVM_ main_vm;
3794 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3795
3796 // Find the Agent_OnUnload function.
3797 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3798 os::find_agent_function(agent,
3799 false,
3800 on_unload_symbols,
3801 num_symbol_entries));
3802
3803 // Invoke the Agent_OnUnload function
3804 if (unload_entry != NULL) {
3805 JavaThread* thread = JavaThread::current();
3806 ThreadToNativeFromVM ttn(thread);
3807 HandleMark hm(thread);
3808 (*unload_entry)(&main_vm);
3809 }
3810 }
3811 }
3812
3813 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3814 // Invokes JVM_OnLoad
3815 void Threads::create_vm_init_libraries() {
3816 extern struct JavaVM_ main_vm;
3817 AgentLibrary* agent;
3818
3819 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3820 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3821
3822 if (on_load_entry != NULL) {
3823 // Invoke the JVM_OnLoad function
3824 JavaThread* thread = JavaThread::current();
3825 ThreadToNativeFromVM ttn(thread);
3826 HandleMark hm(thread);
3827 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3828 if (err != JNI_OK) {
3829 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3830 }
3831 } else {
3832 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3833 }
3834 }
3835 }
3836
3837 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3838 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3839
3840 JavaThread* java_thread = NULL;
3841 // Sequential search for now. Need to do better optimization later.
3842 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3843 oop tobj = thread->threadObj();
3844 if (!thread->is_exiting() &&
3845 tobj != NULL &&
3846 java_tid == java_lang_Thread::thread_id(tobj)) {
3847 java_thread = thread;
3848 break;
3849 }
3850 }
3851 return java_thread;
3852 }
3853
3854
3855 // Last thread running calls java.lang.Shutdown.shutdown()
3856 void JavaThread::invoke_shutdown_hooks() {
3857 HandleMark hm(this);
3858
3859 // We could get here with a pending exception, if so clear it now.
3860 if (this->has_pending_exception()) {
3861 this->clear_pending_exception();
3862 }
3863
3864 EXCEPTION_MARK;
3865 Klass* k =
3866 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3867 THREAD);
3868 if (k != NULL) {
3869 // SystemDictionary::resolve_or_null will return null if there was
3870 // an exception. If we cannot load the Shutdown class, just don't
3871 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3872 // and finalizers (if runFinalizersOnExit is set) won't be run.
3873 // Note that if a shutdown hook was registered or runFinalizersOnExit
3874 // was called, the Shutdown class would have already been loaded
3875 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3876 instanceKlassHandle shutdown_klass (THREAD, k);
3877 JavaValue result(T_VOID);
3878 JavaCalls::call_static(&result,
3879 shutdown_klass,
3880 vmSymbols::shutdown_method_name(),
3881 vmSymbols::void_method_signature(),
3882 THREAD);
3883 }
3884 CLEAR_PENDING_EXCEPTION;
3885 }
3886
3887 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3888 // the program falls off the end of main(). Another VM exit path is through
3889 // vm_exit() when the program calls System.exit() to return a value or when
3890 // there is a serious error in VM. The two shutdown paths are not exactly
3891 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3892 // and VM_Exit op at VM level.
3893 //
3894 // Shutdown sequence:
3895 // + Shutdown native memory tracking if it is on
3896 // + Wait until we are the last non-daemon thread to execute
3897 // <-- every thing is still working at this moment -->
3898 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3899 // shutdown hooks, run finalizers if finalization-on-exit
3900 // + Call before_exit(), prepare for VM exit
3901 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3902 // currently the only user of this mechanism is File.deleteOnExit())
3903 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3904 // post thread end and vm death events to JVMTI,
3905 // stop signal thread
3906 // + Call JavaThread::exit(), it will:
3907 // > release JNI handle blocks, remove stack guard pages
3908 // > remove this thread from Threads list
3909 // <-- no more Java code from this thread after this point -->
3910 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3911 // the compiler threads at safepoint
3912 // <-- do not use anything that could get blocked by Safepoint -->
3913 // + Disable tracing at JNI/JVM barriers
3914 // + Set _vm_exited flag for threads that are still running native code
3915 // + Delete this thread
3916 // + Call exit_globals()
3917 // > deletes tty
3918 // > deletes PerfMemory resources
3919 // + Return to caller
3920
3921 bool Threads::destroy_vm() {
3922 JavaThread* thread = JavaThread::current();
3923
3924 #ifdef ASSERT
3925 _vm_complete = false;
3926 #endif
3927 // Wait until we are the last non-daemon thread to execute
3928 { MutexLocker nu(Threads_lock);
3929 while (Threads::number_of_non_daemon_threads() > 1)
3930 // This wait should make safepoint checks, wait without a timeout,
3931 // and wait as a suspend-equivalent condition.
3932 //
3933 // Note: If the FlatProfiler is running and this thread is waiting
3934 // for another non-daemon thread to finish, then the FlatProfiler
3935 // is waiting for the external suspend request on this thread to
3936 // complete. wait_for_ext_suspend_completion() will eventually
3937 // timeout, but that takes time. Making this wait a suspend-
3938 // equivalent condition solves that timeout problem.
3939 //
3940 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3941 Mutex::_as_suspend_equivalent_flag);
3942 }
3943
3944 // Hang forever on exit if we are reporting an error.
3945 if (ShowMessageBoxOnError && is_error_reported()) {
3946 os::infinite_sleep();
3947 }
3948 os::wait_for_keypress_at_exit();
3949
3950 // run Java level shutdown hooks
3951 thread->invoke_shutdown_hooks();
3952
3953 before_exit(thread);
3954
3955 thread->exit(true);
3956
3957 // Stop GC threads.
3958 Universe::heap()->shutdown();
3959
3960 // Stop VM thread.
3961 {
3962 // 4945125 The vm thread comes to a safepoint during exit.
3963 // GC vm_operations can get caught at the safepoint, and the
3964 // heap is unparseable if they are caught. Grab the Heap_lock
3965 // to prevent this. The GC vm_operations will not be able to
3966 // queue until after the vm thread is dead. After this point,
3967 // we'll never emerge out of the safepoint before the VM exits.
3968
3969 MutexLocker ml(Heap_lock);
3970
3971 VMThread::wait_for_vm_thread_exit();
3972 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3973 VMThread::destroy();
3974 }
3975
3976 // clean up ideal graph printers
3977 #if defined(COMPILER2) && !defined(PRODUCT)
3978 IdealGraphPrinter::clean_up();
3979 #endif
3980
3981 // Now, all Java threads are gone except daemon threads. Daemon threads
3982 // running Java code or in VM are stopped by the Safepoint. However,
3983 // daemon threads executing native code are still running. But they
3984 // will be stopped at native=>Java/VM barriers. Note that we can't
3985 // simply kill or suspend them, as it is inherently deadlock-prone.
3986
3987 #ifndef PRODUCT
3988 // disable function tracing at JNI/JVM barriers
3989 TraceJNICalls = false;
3990 TraceJVMCalls = false;
3991 TraceRuntimeCalls = false;
3992 #endif
3993
3994 VM_Exit::set_vm_exited();
3995
3996 notify_vm_shutdown();
3997
3998 delete thread;
3999
4000 // exit_globals() will delete tty
4001 exit_globals();
4002
4003 return true;
4004 }
4005
4006
4007 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4008 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4009 return is_supported_jni_version(version);
4010 }
4011
4012
4013 jboolean Threads::is_supported_jni_version(jint version) {
4014 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4015 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4016 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4017 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4018 return JNI_FALSE;
4019 }
4020
4021
4022 void Threads::add(JavaThread* p, bool force_daemon) {
4023 // The threads lock must be owned at this point
4024 assert_locked_or_safepoint(Threads_lock);
4025
4026 // See the comment for this method in thread.hpp for its purpose and
4027 // why it is called here.
4028 p->initialize_queues();
4029 p->set_next(_thread_list);
4030 _thread_list = p;
4031 _number_of_threads++;
4032 oop threadObj = p->threadObj();
4033 bool daemon = true;
4034 // Bootstrapping problem: threadObj can be null for initial
4035 // JavaThread (or for threads attached via JNI)
4036 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4037 _number_of_non_daemon_threads++;
4038 daemon = false;
4039 }
4040
4041 ThreadService::add_thread(p, daemon);
4042
4043 // Possible GC point.
4044 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4045 }
4046
4047 void Threads::remove(JavaThread* p) {
4048 // Extra scope needed for Thread_lock, so we can check
4049 // that we do not remove thread without safepoint code notice
4050 { MutexLocker ml(Threads_lock);
4051
4052 assert(includes(p), "p must be present");
4053
4054 JavaThread* current = _thread_list;
4055 JavaThread* prev = NULL;
4056
4057 while (current != p) {
4058 prev = current;
4059 current = current->next();
4060 }
4061
4062 if (prev) {
4063 prev->set_next(current->next());
4064 } else {
4065 _thread_list = p->next();
4066 }
4067 _number_of_threads--;
4068 oop threadObj = p->threadObj();
4069 bool daemon = true;
4070 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4071 _number_of_non_daemon_threads--;
4072 daemon = false;
4073
4074 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4075 // on destroy_vm will wake up.
4076 if (number_of_non_daemon_threads() == 1) {
4077 Threads_lock->notify_all();
4078 }
4079 }
4080 ThreadService::remove_thread(p, daemon);
4081
4082 // Make sure that safepoint code disregard this thread. This is needed since
4083 // the thread might mess around with locks after this point. This can cause it
4084 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4085 // of this thread since it is removed from the queue.
4086 p->set_terminated_value();
4087 } // unlock Threads_lock
4088
4089 // Since Events::log uses a lock, we grab it outside the Threads_lock
4090 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4091 }
4092
4093 // Threads_lock must be held when this is called (or must be called during a safepoint)
4094 bool Threads::includes(JavaThread* p) {
4095 assert(Threads_lock->is_locked(), "sanity check");
4096 ALL_JAVA_THREADS(q) {
4097 if (q == p) {
4098 return true;
4099 }
4100 }
4101 return false;
4102 }
4103
4104 // Operations on the Threads list for GC. These are not explicitly locked,
4105 // but the garbage collector must provide a safe context for them to run.
4106 // In particular, these things should never be called when the Threads_lock
4107 // is held by some other thread. (Note: the Safepoint abstraction also
4108 // uses the Threads_lock to guarantee this property. It also makes sure that
4109 // all threads gets blocked when exiting or starting).
4110
4111 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4112 ALL_JAVA_THREADS(p) {
4113 p->oops_do(f, cld_f, cf);
4114 }
4115 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4116 }
4117
4118 void Threads::change_thread_claim_parity() {
4119 // Set the new claim parity.
4120 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4121 "Not in range.");
4122 _thread_claim_parity++;
4123 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4124 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4125 "Not in range.");
4126 }
4127
4128 #ifdef ASSERT
4129 void Threads::assert_all_threads_claimed() {
4130 ALL_JAVA_THREADS(p) {
4131 const int thread_parity = p->oops_do_parity();
4132 assert((thread_parity == _thread_claim_parity),
4133 err_msg("Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity));
4134 }
4135 }
4136 #endif // ASSERT
4137
4138 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4139 int cp = Threads::thread_claim_parity();
4140 ALL_JAVA_THREADS(p) {
4141 if (p->claim_oops_do(is_par, cp)) {
4142 p->oops_do(f, cld_f, cf);
4143 }
4144 }
4145 VMThread* vmt = VMThread::vm_thread();
4146 if (vmt->claim_oops_do(is_par, cp)) {
4147 vmt->oops_do(f, cld_f, cf);
4148 }
4149 }
4150
4151 #if INCLUDE_ALL_GCS
4152 // Used by ParallelScavenge
4153 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4154 ALL_JAVA_THREADS(p) {
4155 q->enqueue(new ThreadRootsTask(p));
4156 }
4157 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4158 }
4159
4160 // Used by Parallel Old
4161 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4162 ALL_JAVA_THREADS(p) {
4163 q->enqueue(new ThreadRootsMarkingTask(p));
4164 }
4165 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4166 }
4167 #endif // INCLUDE_ALL_GCS
4168
4169 void Threads::nmethods_do(CodeBlobClosure* cf) {
4170 ALL_JAVA_THREADS(p) {
4171 p->nmethods_do(cf);
4172 }
4173 VMThread::vm_thread()->nmethods_do(cf);
4174 }
4175
4176 void Threads::metadata_do(void f(Metadata*)) {
4177 ALL_JAVA_THREADS(p) {
4178 p->metadata_do(f);
4179 }
4180 }
4181
4182 class ThreadHandlesClosure : public ThreadClosure {
4183 void (*_f)(Metadata*);
4184 public:
4185 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4186 virtual void do_thread(Thread* thread) {
4187 thread->metadata_handles_do(_f);
4188 }
4189 };
4190
4191 void Threads::metadata_handles_do(void f(Metadata*)) {
4192 // Only walk the Handles in Thread.
4193 ThreadHandlesClosure handles_closure(f);
4194 threads_do(&handles_closure);
4195 }
4196
4197 void Threads::deoptimized_wrt_marked_nmethods() {
4198 ALL_JAVA_THREADS(p) {
4199 p->deoptimized_wrt_marked_nmethods();
4200 }
4201 }
4202
4203
4204 // Get count Java threads that are waiting to enter the specified monitor.
4205 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4206 address monitor,
4207 bool doLock) {
4208 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4209 "must grab Threads_lock or be at safepoint");
4210 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4211
4212 int i = 0;
4213 {
4214 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4215 ALL_JAVA_THREADS(p) {
4216 if (p->is_Compiler_thread()) continue;
4217
4218 address pending = (address)p->current_pending_monitor();
4219 if (pending == monitor) { // found a match
4220 if (i < count) result->append(p); // save the first count matches
4221 i++;
4222 }
4223 }
4224 }
4225 return result;
4226 }
4227
4228
4229 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4230 bool doLock) {
4231 assert(doLock ||
4232 Threads_lock->owned_by_self() ||
4233 SafepointSynchronize::is_at_safepoint(),
4234 "must grab Threads_lock or be at safepoint");
4235
4236 // NULL owner means not locked so we can skip the search
4237 if (owner == NULL) return NULL;
4238
4239 {
4240 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4241 ALL_JAVA_THREADS(p) {
4242 // first, see if owner is the address of a Java thread
4243 if (owner == (address)p) return p;
4244 }
4245 }
4246 // Cannot assert on lack of success here since this function may be
4247 // used by code that is trying to report useful problem information
4248 // like deadlock detection.
4249 if (UseHeavyMonitors) return NULL;
4250
4251 // If we didn't find a matching Java thread and we didn't force use of
4252 // heavyweight monitors, then the owner is the stack address of the
4253 // Lock Word in the owning Java thread's stack.
4254 //
4255 JavaThread* the_owner = NULL;
4256 {
4257 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4258 ALL_JAVA_THREADS(q) {
4259 if (q->is_lock_owned(owner)) {
4260 the_owner = q;
4261 break;
4262 }
4263 }
4264 }
4265 // cannot assert on lack of success here; see above comment
4266 return the_owner;
4267 }
4268
4269 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4270 void Threads::print_on(outputStream* st, bool print_stacks,
4271 bool internal_format, bool print_concurrent_locks) {
4272 char buf[32];
4273 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4274
4275 st->print_cr("Full thread dump %s (%s %s):",
4276 Abstract_VM_Version::vm_name(),
4277 Abstract_VM_Version::vm_release(),
4278 Abstract_VM_Version::vm_info_string());
4279 st->cr();
4280
4281 #if INCLUDE_SERVICES
4282 // Dump concurrent locks
4283 ConcurrentLocksDump concurrent_locks;
4284 if (print_concurrent_locks) {
4285 concurrent_locks.dump_at_safepoint();
4286 }
4287 #endif // INCLUDE_SERVICES
4288
4289 ALL_JAVA_THREADS(p) {
4290 ResourceMark rm;
4291 p->print_on(st);
4292 if (print_stacks) {
4293 if (internal_format) {
4294 p->trace_stack();
4295 } else {
4296 p->print_stack_on(st);
4297 }
4298 }
4299 st->cr();
4300 #if INCLUDE_SERVICES
4301 if (print_concurrent_locks) {
4302 concurrent_locks.print_locks_on(p, st);
4303 }
4304 #endif // INCLUDE_SERVICES
4305 }
4306
4307 VMThread::vm_thread()->print_on(st);
4308 st->cr();
4309 Universe::heap()->print_gc_threads_on(st);
4310 WatcherThread* wt = WatcherThread::watcher_thread();
4311 if (wt != NULL) {
4312 wt->print_on(st);
4313 st->cr();
4314 }
4315 CompileBroker::print_compiler_threads_on(st);
4316 st->flush();
4317 }
4318
4319 // Threads::print_on_error() is called by fatal error handler. It's possible
4320 // that VM is not at safepoint and/or current thread is inside signal handler.
4321 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4322 // memory (even in resource area), it might deadlock the error handler.
4323 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4324 int buflen) {
4325 bool found_current = false;
4326 st->print_cr("Java Threads: ( => current thread )");
4327 ALL_JAVA_THREADS(thread) {
4328 bool is_current = (current == thread);
4329 found_current = found_current || is_current;
4330
4331 st->print("%s", is_current ? "=>" : " ");
4332
4333 st->print(PTR_FORMAT, thread);
4334 st->print(" ");
4335 thread->print_on_error(st, buf, buflen);
4336 st->cr();
4337 }
4338 st->cr();
4339
4340 st->print_cr("Other Threads:");
4341 if (VMThread::vm_thread()) {
4342 bool is_current = (current == VMThread::vm_thread());
4343 found_current = found_current || is_current;
4344 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4345
4346 st->print(PTR_FORMAT, VMThread::vm_thread());
4347 st->print(" ");
4348 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4349 st->cr();
4350 }
4351 WatcherThread* wt = WatcherThread::watcher_thread();
4352 if (wt != NULL) {
4353 bool is_current = (current == wt);
4354 found_current = found_current || is_current;
4355 st->print("%s", is_current ? "=>" : " ");
4356
4357 st->print(PTR_FORMAT, wt);
4358 st->print(" ");
4359 wt->print_on_error(st, buf, buflen);
4360 st->cr();
4361 }
4362 if (!found_current) {
4363 st->cr();
4364 st->print("=>" PTR_FORMAT " (exited) ", current);
4365 current->print_on_error(st, buf, buflen);
4366 st->cr();
4367 }
4368 }
4369
4370 // Internal SpinLock and Mutex
4371 // Based on ParkEvent
4372
4373 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4374 //
4375 // We employ SpinLocks _only for low-contention, fixed-length
4376 // short-duration critical sections where we're concerned
4377 // about native mutex_t or HotSpot Mutex:: latency.
4378 // The mux construct provides a spin-then-block mutual exclusion
4379 // mechanism.
4380 //
4381 // Testing has shown that contention on the ListLock guarding gFreeList
4382 // is common. If we implement ListLock as a simple SpinLock it's common
4383 // for the JVM to devolve to yielding with little progress. This is true
4384 // despite the fact that the critical sections protected by ListLock are
4385 // extremely short.
4386 //
4387 // TODO-FIXME: ListLock should be of type SpinLock.
4388 // We should make this a 1st-class type, integrated into the lock
4389 // hierarchy as leaf-locks. Critically, the SpinLock structure
4390 // should have sufficient padding to avoid false-sharing and excessive
4391 // cache-coherency traffic.
4392
4393
4394 typedef volatile int SpinLockT;
4395
4396 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4397 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4398 return; // normal fast-path return
4399 }
4400
4401 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4402 TEVENT(SpinAcquire - ctx);
4403 int ctr = 0;
4404 int Yields = 0;
4405 for (;;) {
4406 while (*adr != 0) {
4407 ++ctr;
4408 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4409 if (Yields > 5) {
4410 os::naked_short_sleep(1);
4411 } else {
4412 os::naked_yield();
4413 ++Yields;
4414 }
4415 } else {
4416 SpinPause();
4417 }
4418 }
4419 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4420 }
4421 }
4422
4423 void Thread::SpinRelease(volatile int * adr) {
4424 assert(*adr != 0, "invariant");
4425 OrderAccess::fence(); // guarantee at least release consistency.
4426 // Roach-motel semantics.
4427 // It's safe if subsequent LDs and STs float "up" into the critical section,
4428 // but prior LDs and STs within the critical section can't be allowed
4429 // to reorder or float past the ST that releases the lock.
4430 // Loads and stores in the critical section - which appear in program
4431 // order before the store that releases the lock - must also appear
4432 // before the store that releases the lock in memory visibility order.
4433 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4434 // the ST of 0 into the lock-word which releases the lock, so fence
4435 // more than covers this on all platforms.
4436 *adr = 0;
4437 }
4438
4439 // muxAcquire and muxRelease:
4440 //
4441 // * muxAcquire and muxRelease support a single-word lock-word construct.
4442 // The LSB of the word is set IFF the lock is held.
4443 // The remainder of the word points to the head of a singly-linked list
4444 // of threads blocked on the lock.
4445 //
4446 // * The current implementation of muxAcquire-muxRelease uses its own
4447 // dedicated Thread._MuxEvent instance. If we're interested in
4448 // minimizing the peak number of extant ParkEvent instances then
4449 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4450 // as certain invariants were satisfied. Specifically, care would need
4451 // to be taken with regards to consuming unpark() "permits".
4452 // A safe rule of thumb is that a thread would never call muxAcquire()
4453 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4454 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4455 // consume an unpark() permit intended for monitorenter, for instance.
4456 // One way around this would be to widen the restricted-range semaphore
4457 // implemented in park(). Another alternative would be to provide
4458 // multiple instances of the PlatformEvent() for each thread. One
4459 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4460 //
4461 // * Usage:
4462 // -- Only as leaf locks
4463 // -- for short-term locking only as muxAcquire does not perform
4464 // thread state transitions.
4465 //
4466 // Alternatives:
4467 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4468 // but with parking or spin-then-park instead of pure spinning.
4469 // * Use Taura-Oyama-Yonenzawa locks.
4470 // * It's possible to construct a 1-0 lock if we encode the lockword as
4471 // (List,LockByte). Acquire will CAS the full lockword while Release
4472 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4473 // acquiring threads use timers (ParkTimed) to detect and recover from
4474 // the stranding window. Thread/Node structures must be aligned on 256-byte
4475 // boundaries by using placement-new.
4476 // * Augment MCS with advisory back-link fields maintained with CAS().
4477 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4478 // The validity of the backlinks must be ratified before we trust the value.
4479 // If the backlinks are invalid the exiting thread must back-track through the
4480 // the forward links, which are always trustworthy.
4481 // * Add a successor indication. The LockWord is currently encoded as
4482 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4483 // to provide the usual futile-wakeup optimization.
4484 // See RTStt for details.
4485 // * Consider schedctl.sc_nopreempt to cover the critical section.
4486 //
4487
4488
4489 typedef volatile intptr_t MutexT; // Mux Lock-word
4490 enum MuxBits { LOCKBIT = 1 };
4491
4492 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4493 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4494 if (w == 0) return;
4495 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4496 return;
4497 }
4498
4499 TEVENT(muxAcquire - Contention);
4500 ParkEvent * const Self = Thread::current()->_MuxEvent;
4501 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4502 for (;;) {
4503 int its = (os::is_MP() ? 100 : 0) + 1;
4504
4505 // Optional spin phase: spin-then-park strategy
4506 while (--its >= 0) {
4507 w = *Lock;
4508 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4509 return;
4510 }
4511 }
4512
4513 Self->reset();
4514 Self->OnList = intptr_t(Lock);
4515 // The following fence() isn't _strictly necessary as the subsequent
4516 // CAS() both serializes execution and ratifies the fetched *Lock value.
4517 OrderAccess::fence();
4518 for (;;) {
4519 w = *Lock;
4520 if ((w & LOCKBIT) == 0) {
4521 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4522 Self->OnList = 0; // hygiene - allows stronger asserts
4523 return;
4524 }
4525 continue; // Interference -- *Lock changed -- Just retry
4526 }
4527 assert(w & LOCKBIT, "invariant");
4528 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4529 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4530 }
4531
4532 while (Self->OnList != 0) {
4533 Self->park();
4534 }
4535 }
4536 }
4537
4538 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4539 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4540 if (w == 0) return;
4541 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4542 return;
4543 }
4544
4545 TEVENT(muxAcquire - Contention);
4546 ParkEvent * ReleaseAfter = NULL;
4547 if (ev == NULL) {
4548 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4549 }
4550 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4551 for (;;) {
4552 guarantee(ev->OnList == 0, "invariant");
4553 int its = (os::is_MP() ? 100 : 0) + 1;
4554
4555 // Optional spin phase: spin-then-park strategy
4556 while (--its >= 0) {
4557 w = *Lock;
4558 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4559 if (ReleaseAfter != NULL) {
4560 ParkEvent::Release(ReleaseAfter);
4561 }
4562 return;
4563 }
4564 }
4565
4566 ev->reset();
4567 ev->OnList = intptr_t(Lock);
4568 // The following fence() isn't _strictly necessary as the subsequent
4569 // CAS() both serializes execution and ratifies the fetched *Lock value.
4570 OrderAccess::fence();
4571 for (;;) {
4572 w = *Lock;
4573 if ((w & LOCKBIT) == 0) {
4574 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4575 ev->OnList = 0;
4576 // We call ::Release while holding the outer lock, thus
4577 // artificially lengthening the critical section.
4578 // Consider deferring the ::Release() until the subsequent unlock(),
4579 // after we've dropped the outer lock.
4580 if (ReleaseAfter != NULL) {
4581 ParkEvent::Release(ReleaseAfter);
4582 }
4583 return;
4584 }
4585 continue; // Interference -- *Lock changed -- Just retry
4586 }
4587 assert(w & LOCKBIT, "invariant");
4588 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4589 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4590 }
4591
4592 while (ev->OnList != 0) {
4593 ev->park();
4594 }
4595 }
4596 }
4597
4598 // Release() must extract a successor from the list and then wake that thread.
4599 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4600 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4601 // Release() would :
4602 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4603 // (B) Extract a successor from the private list "in-hand"
4604 // (C) attempt to CAS() the residual back into *Lock over null.
4605 // If there were any newly arrived threads and the CAS() would fail.
4606 // In that case Release() would detach the RATs, re-merge the list in-hand
4607 // with the RATs and repeat as needed. Alternately, Release() might
4608 // detach and extract a successor, but then pass the residual list to the wakee.
4609 // The wakee would be responsible for reattaching and remerging before it
4610 // competed for the lock.
4611 //
4612 // Both "pop" and DMR are immune from ABA corruption -- there can be
4613 // multiple concurrent pushers, but only one popper or detacher.
4614 // This implementation pops from the head of the list. This is unfair,
4615 // but tends to provide excellent throughput as hot threads remain hot.
4616 // (We wake recently run threads first).
4617 //
4618 // All paths through muxRelease() will execute a CAS.
4619 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4620 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4621 // executed within the critical section are complete and globally visible before the
4622 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4623 void Thread::muxRelease(volatile intptr_t * Lock) {
4624 for (;;) {
4625 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4626 assert(w & LOCKBIT, "invariant");
4627 if (w == LOCKBIT) return;
4628 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4629 assert(List != NULL, "invariant");
4630 assert(List->OnList == intptr_t(Lock), "invariant");
4631 ParkEvent * const nxt = List->ListNext;
4632 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4633
4634 // The following CAS() releases the lock and pops the head element.
4635 // The CAS() also ratifies the previously fetched lock-word value.
4636 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4637 continue;
4638 }
4639 List->OnList = 0;
4640 OrderAccess::fence();
4641 List->unpark();
4642 return;
4643 }
4644 }
4645
4646
4647 void Threads::verify() {
4648 ALL_JAVA_THREADS(p) {
4649 p->verify();
4650 }
4651 VMThread* thread = VMThread::vm_thread();
4652 if (thread != NULL) thread->verify();
4653 }