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