1 /*
2 * Copyright (c) 1997, 2013, 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/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jvmtifiles/jvmtiEnv.hpp"
36 #include "memory/gcLocker.inline.hpp"
37 #include "memory/oopFactory.hpp"
38 #include "memory/universe.inline.hpp"
39 #include "oops/instanceKlass.hpp"
40 #include "oops/objArrayOop.hpp"
41 #include "oops/oop.inline.hpp"
42 #include "oops/symbol.hpp"
43 #include "prims/jvm_misc.hpp"
44 #include "prims/jvmtiExport.hpp"
45 #include "prims/jvmtiThreadState.hpp"
46 #include "prims/privilegedStack.hpp"
47 #include "runtime/aprofiler.hpp"
48 #include "runtime/arguments.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/deoptimization.hpp"
51 #include "runtime/fprofiler.hpp"
52 #include "runtime/frame.inline.hpp"
53 #include "runtime/init.hpp"
54 #include "runtime/interfaceSupport.hpp"
55 #include "runtime/java.hpp"
56 #include "runtime/javaCalls.hpp"
57 #include "runtime/jniPeriodicChecker.hpp"
58 #include "runtime/memprofiler.hpp"
59 #include "runtime/mutexLocker.hpp"
60 #include "runtime/objectMonitor.hpp"
61 #include "runtime/osThread.hpp"
62 #include "runtime/safepoint.hpp"
63 #include "runtime/sharedRuntime.hpp"
64 #include "runtime/statSampler.hpp"
65 #include "runtime/stubRoutines.hpp"
66 #include "runtime/task.hpp"
67 #include "runtime/threadCritical.hpp"
68 #include "runtime/threadLocalStorage.hpp"
69 #include "runtime/vframe.hpp"
70 #include "runtime/vframeArray.hpp"
71 #include "runtime/vframe_hp.hpp"
72 #include "runtime/vmThread.hpp"
73 #include "runtime/vm_operations.hpp"
74 #include "services/attachListener.hpp"
75 #include "services/management.hpp"
76 #include "services/memTracker.hpp"
77 #include "services/threadService.hpp"
78 #include "trace/tracing.hpp"
79 #include "trace/traceMacros.hpp"
80 #include "utilities/defaultStream.hpp"
81 #include "utilities/dtrace.hpp"
82 #include "utilities/events.hpp"
83 #include "utilities/preserveException.hpp"
84 #ifdef TARGET_OS_FAMILY_linux
85 # include "os_linux.inline.hpp"
86 # include "thread_linux.inline.hpp"
87 #endif
88 #ifdef TARGET_OS_FAMILY_solaris
89 # include "os_solaris.inline.hpp"
90 # include "thread_solaris.inline.hpp"
91 #endif
92 #ifdef TARGET_OS_FAMILY_windows
93 # include "os_windows.inline.hpp"
94 # include "thread_windows.inline.hpp"
95 #endif
96 #ifdef TARGET_OS_FAMILY_bsd
97 # include "os_bsd.inline.hpp"
98 # include "thread_bsd.inline.hpp"
99 #endif
100 #ifndef SERIALGC
101 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
102 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
103 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
104 #endif
105 #ifdef COMPILER1
106 #include "c1/c1_Compiler.hpp"
107 #endif
108 #ifdef COMPILER2
109 #include "opto/c2compiler.hpp"
110 #include "opto/idealGraphPrinter.hpp"
111 #endif
112
113 #ifdef DTRACE_ENABLED
114
115 // Only bother with this argument setup if dtrace is available
116
117 #ifndef USDT2
118 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
119 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
120 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
121 intptr_t, intptr_t, bool);
122 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
123 intptr_t, intptr_t, bool);
124
125 #define DTRACE_THREAD_PROBE(probe, javathread) \
126 { \
127 ResourceMark rm(this); \
128 int len = 0; \
129 const char* name = (javathread)->get_thread_name(); \
130 len = strlen(name); \
131 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
132 name, len, \
133 java_lang_Thread::thread_id((javathread)->threadObj()), \
134 (javathread)->osthread()->thread_id(), \
135 java_lang_Thread::is_daemon((javathread)->threadObj())); \
136 }
137
138 #else /* USDT2 */
139
140 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
141 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
142
143 #define DTRACE_THREAD_PROBE(probe, javathread) \
144 { \
145 ResourceMark rm(this); \
146 int len = 0; \
147 const char* name = (javathread)->get_thread_name(); \
148 len = strlen(name); \
149 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
150 (char *) name, len, \
151 java_lang_Thread::thread_id((javathread)->threadObj()), \
152 (uintptr_t) (javathread)->osthread()->thread_id(), \
153 java_lang_Thread::is_daemon((javathread)->threadObj())); \
154 }
155
156 #endif /* USDT2 */
157
158 #else // ndef DTRACE_ENABLED
159
160 #define DTRACE_THREAD_PROBE(probe, javathread)
161
162 #endif // ndef DTRACE_ENABLED
163
164
165 // Class hierarchy
166 // - Thread
167 // - VMThread
168 // - WatcherThread
169 // - ConcurrentMarkSweepThread
170 // - JavaThread
171 // - CompilerThread
172
173 // ======= Thread ========
174 // Support for forcing alignment of thread objects for biased locking
175 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
176 if (UseBiasedLocking) {
177 const int alignment = markOopDesc::biased_lock_alignment;
178 size_t aligned_size = size + (alignment - sizeof(intptr_t));
179 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
180 : os::malloc(aligned_size, flags, CURRENT_PC);
181 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
182 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
183 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
184 "JavaThread alignment code overflowed allocated storage");
185 if (TraceBiasedLocking) {
186 if (aligned_addr != real_malloc_addr)
187 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
188 real_malloc_addr, aligned_addr);
189 }
190 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
191 return aligned_addr;
192 } else {
193 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
194 : os::malloc(size, flags, CURRENT_PC);
195 }
196 }
197
198 void Thread::operator delete(void* p) {
199 if (UseBiasedLocking) {
200 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
201 FreeHeap(real_malloc_addr, mtThread);
202 } else {
203 FreeHeap(p, mtThread);
204 }
205 }
206
207
208 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
209 // JavaThread
210
211
212 Thread::Thread() {
213 // stack and get_thread
214 set_stack_base(NULL);
215 set_stack_size(0);
216 set_self_raw_id(0);
217 set_lgrp_id(-1);
218
219 // allocated data structures
220 set_osthread(NULL);
221 set_resource_area(new (mtThread)ResourceArea());
222 set_handle_area(new (mtThread) HandleArea(NULL));
223 set_active_handles(NULL);
224 set_free_handle_block(NULL);
225 set_last_handle_mark(NULL);
226
227 // This initial value ==> never claimed.
228 _oops_do_parity = 0;
229
230 // the handle mark links itself to last_handle_mark
231 new HandleMark(this);
232
233 // plain initialization
234 debug_only(_owned_locks = NULL;)
235 debug_only(_allow_allocation_count = 0;)
236 NOT_PRODUCT(_allow_safepoint_count = 0;)
237 NOT_PRODUCT(_skip_gcalot = false;)
238 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
239 _jvmti_env_iteration_count = 0;
240 set_allocated_bytes(0);
241 _vm_operation_started_count = 0;
242 _vm_operation_completed_count = 0;
243 _current_pending_monitor = NULL;
244 _current_pending_monitor_is_from_java = true;
245 _current_waiting_monitor = NULL;
246 _num_nested_signal = 0;
247 omFreeList = NULL ;
248 omFreeCount = 0 ;
249 omFreeProvision = 32 ;
250 omInUseList = NULL ;
251 omInUseCount = 0 ;
252
253 #ifdef ASSERT
254 _visited_for_critical_count = false;
255 #endif
256
257 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
258 _suspend_flags = 0;
259
260 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
261 _hashStateX = os::random() ;
262 _hashStateY = 842502087 ;
263 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
264 _hashStateW = 273326509 ;
265
266 _OnTrap = 0 ;
267 _schedctl = NULL ;
268 _Stalled = 0 ;
269 _TypeTag = 0x2BAD ;
270
271 // Many of the following fields are effectively final - immutable
272 // Note that nascent threads can't use the Native Monitor-Mutex
273 // construct until the _MutexEvent is initialized ...
274 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
275 // we might instead use a stack of ParkEvents that we could provision on-demand.
276 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
277 // and ::Release()
278 _ParkEvent = ParkEvent::Allocate (this) ;
279 _SleepEvent = ParkEvent::Allocate (this) ;
280 _MutexEvent = ParkEvent::Allocate (this) ;
281 _MuxEvent = ParkEvent::Allocate (this) ;
282
283 #ifdef CHECK_UNHANDLED_OOPS
284 if (CheckUnhandledOops) {
285 _unhandled_oops = new UnhandledOops(this);
286 }
287 #endif // CHECK_UNHANDLED_OOPS
288 #ifdef ASSERT
289 if (UseBiasedLocking) {
290 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
291 assert(this == _real_malloc_address ||
292 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
293 "bug in forced alignment of thread objects");
294 }
295 #endif /* ASSERT */
296 }
297
298 void Thread::initialize_thread_local_storage() {
299 // Note: Make sure this method only calls
300 // non-blocking operations. Otherwise, it might not work
301 // with the thread-startup/safepoint interaction.
302
303 // During Java thread startup, safepoint code should allow this
304 // method to complete because it may need to allocate memory to
305 // store information for the new thread.
306
307 // initialize structure dependent on thread local storage
308 ThreadLocalStorage::set_thread(this);
309 }
310
311 void Thread::record_stack_base_and_size() {
312 set_stack_base(os::current_stack_base());
313 set_stack_size(os::current_stack_size());
314 // CR 7190089: on Solaris, primordial thread's stack is adjusted
315 // in initialize_thread(). Without the adjustment, stack size is
316 // incorrect if stack is set to unlimited (ulimit -s unlimited).
317 // So far, only Solaris has real implementation of initialize_thread().
318 //
319 // set up any platform-specific state.
320 os::initialize_thread(this);
321
322 // record thread's native stack, stack grows downward
323 if (MemTracker::is_on()) {
324 address stack_low_addr = stack_base() - stack_size();
325 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this,
326 CURRENT_PC);
327 }
328 }
329
330
331 Thread::~Thread() {
332 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
333 ObjectSynchronizer::omFlush (this) ;
334
335 // stack_base can be NULL if the thread is never started or exited before
336 // record_stack_base_and_size called. Although, we would like to ensure
337 // that all started threads do call record_stack_base_and_size(), there is
338 // not proper way to enforce that.
339 if (_stack_base != NULL) {
340 address low_stack_addr = stack_base() - stack_size();
341 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this);
342 #ifdef ASSERT
343 set_stack_base(NULL);
344 #endif
345 }
346
347 // deallocate data structures
348 delete resource_area();
349 // since the handle marks are using the handle area, we have to deallocated the root
350 // handle mark before deallocating the thread's handle area,
351 assert(last_handle_mark() != NULL, "check we have an element");
352 delete last_handle_mark();
353 assert(last_handle_mark() == NULL, "check we have reached the end");
354
355 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
356 // We NULL out the fields for good hygiene.
357 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
358 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
359 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
360 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
361
362 delete handle_area();
363
364 // osthread() can be NULL, if creation of thread failed.
365 if (osthread() != NULL) os::free_thread(osthread());
366
367 delete _SR_lock;
368
369 // clear thread local storage if the Thread is deleting itself
370 if (this == Thread::current()) {
371 ThreadLocalStorage::set_thread(NULL);
372 } else {
373 // In the case where we're not the current thread, invalidate all the
374 // caches in case some code tries to get the current thread or the
375 // thread that was destroyed, and gets stale information.
376 ThreadLocalStorage::invalidate_all();
377 }
378 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
379 }
380
381 // NOTE: dummy function for assertion purpose.
382 void Thread::run() {
383 ShouldNotReachHere();
384 }
385
386 #ifdef ASSERT
387 // Private method to check for dangling thread pointer
388 void check_for_dangling_thread_pointer(Thread *thread) {
389 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
390 "possibility of dangling Thread pointer");
391 }
392 #endif
393
394
395 #ifndef PRODUCT
396 // Tracing method for basic thread operations
397 void Thread::trace(const char* msg, const Thread* const thread) {
398 if (!TraceThreadEvents) return;
399 ResourceMark rm;
400 ThreadCritical tc;
401 const char *name = "non-Java thread";
402 int prio = -1;
403 if (thread->is_Java_thread()
404 && !thread->is_Compiler_thread()) {
405 // The Threads_lock must be held to get information about
406 // this thread but may not be in some situations when
407 // tracing thread events.
408 bool release_Threads_lock = false;
409 if (!Threads_lock->owned_by_self()) {
410 Threads_lock->lock();
411 release_Threads_lock = true;
412 }
413 JavaThread* jt = (JavaThread *)thread;
414 name = (char *)jt->get_thread_name();
415 oop thread_oop = jt->threadObj();
416 if (thread_oop != NULL) {
417 prio = java_lang_Thread::priority(thread_oop);
418 }
419 if (release_Threads_lock) {
420 Threads_lock->unlock();
421 }
422 }
423 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
424 }
425 #endif
426
427
428 ThreadPriority Thread::get_priority(const Thread* const thread) {
429 trace("get priority", thread);
430 ThreadPriority priority;
431 // Can return an error!
432 (void)os::get_priority(thread, priority);
433 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
434 return priority;
435 }
436
437 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
438 trace("set priority", thread);
439 debug_only(check_for_dangling_thread_pointer(thread);)
440 // Can return an error!
441 (void)os::set_priority(thread, priority);
442 }
443
444
445 void Thread::start(Thread* thread) {
446 trace("start", thread);
447 // Start is different from resume in that its safety is guaranteed by context or
448 // being called from a Java method synchronized on the Thread object.
449 if (!DisableStartThread) {
450 if (thread->is_Java_thread()) {
451 // Initialize the thread state to RUNNABLE before starting this thread.
452 // Can not set it after the thread started because we do not know the
453 // exact thread state at that time. It could be in MONITOR_WAIT or
454 // in SLEEPING or some other state.
455 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
456 java_lang_Thread::RUNNABLE);
457 }
458 os::start_thread(thread);
459 }
460 }
461
462 // Enqueue a VM_Operation to do the job for us - sometime later
463 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
464 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
465 VMThread::execute(vm_stop);
466 }
467
468
469 //
470 // Check if an external suspend request has completed (or has been
471 // cancelled). Returns true if the thread is externally suspended and
472 // false otherwise.
473 //
474 // The bits parameter returns information about the code path through
475 // the routine. Useful for debugging:
476 //
477 // set in is_ext_suspend_completed():
478 // 0x00000001 - routine was entered
479 // 0x00000010 - routine return false at end
480 // 0x00000100 - thread exited (return false)
481 // 0x00000200 - suspend request cancelled (return false)
482 // 0x00000400 - thread suspended (return true)
483 // 0x00001000 - thread is in a suspend equivalent state (return true)
484 // 0x00002000 - thread is native and walkable (return true)
485 // 0x00004000 - thread is native_trans and walkable (needed retry)
486 //
487 // set in wait_for_ext_suspend_completion():
488 // 0x00010000 - routine was entered
489 // 0x00020000 - suspend request cancelled before loop (return false)
490 // 0x00040000 - thread suspended before loop (return true)
491 // 0x00080000 - suspend request cancelled in loop (return false)
492 // 0x00100000 - thread suspended in loop (return true)
493 // 0x00200000 - suspend not completed during retry loop (return false)
494 //
495
496 // Helper class for tracing suspend wait debug bits.
497 //
498 // 0x00000100 indicates that the target thread exited before it could
499 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
500 // 0x00080000 each indicate a cancelled suspend request so they don't
501 // count as wait failures either.
502 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
503
504 class TraceSuspendDebugBits : public StackObj {
505 private:
506 JavaThread * jt;
507 bool is_wait;
508 bool called_by_wait; // meaningful when !is_wait
509 uint32_t * bits;
510
511 public:
512 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
513 uint32_t *_bits) {
514 jt = _jt;
515 is_wait = _is_wait;
516 called_by_wait = _called_by_wait;
517 bits = _bits;
518 }
519
520 ~TraceSuspendDebugBits() {
521 if (!is_wait) {
522 #if 1
523 // By default, don't trace bits for is_ext_suspend_completed() calls.
524 // That trace is very chatty.
525 return;
526 #else
527 if (!called_by_wait) {
528 // If tracing for is_ext_suspend_completed() is enabled, then only
529 // trace calls to it from wait_for_ext_suspend_completion()
530 return;
531 }
532 #endif
533 }
534
535 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
536 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
537 MutexLocker ml(Threads_lock); // needed for get_thread_name()
538 ResourceMark rm;
539
540 tty->print_cr(
541 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
542 jt->get_thread_name(), *bits);
543
544 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
545 }
546 }
547 }
548 };
549 #undef DEBUG_FALSE_BITS
550
551
552 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
553 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
554
555 bool did_trans_retry = false; // only do thread_in_native_trans retry once
556 bool do_trans_retry; // flag to force the retry
557
558 *bits |= 0x00000001;
559
560 do {
561 do_trans_retry = false;
562
563 if (is_exiting()) {
564 // Thread is in the process of exiting. This is always checked
565 // first to reduce the risk of dereferencing a freed JavaThread.
566 *bits |= 0x00000100;
567 return false;
568 }
569
570 if (!is_external_suspend()) {
571 // Suspend request is cancelled. This is always checked before
572 // is_ext_suspended() to reduce the risk of a rogue resume
573 // confusing the thread that made the suspend request.
574 *bits |= 0x00000200;
575 return false;
576 }
577
578 if (is_ext_suspended()) {
579 // thread is suspended
580 *bits |= 0x00000400;
581 return true;
582 }
583
584 // Now that we no longer do hard suspends of threads running
585 // native code, the target thread can be changing thread state
586 // while we are in this routine:
587 //
588 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
589 //
590 // We save a copy of the thread state as observed at this moment
591 // and make our decision about suspend completeness based on the
592 // copy. This closes the race where the thread state is seen as
593 // _thread_in_native_trans in the if-thread_blocked check, but is
594 // seen as _thread_blocked in if-thread_in_native_trans check.
595 JavaThreadState save_state = thread_state();
596
597 if (save_state == _thread_blocked && is_suspend_equivalent()) {
598 // If the thread's state is _thread_blocked and this blocking
599 // condition is known to be equivalent to a suspend, then we can
600 // consider the thread to be externally suspended. This means that
601 // the code that sets _thread_blocked has been modified to do
602 // self-suspension if the blocking condition releases. We also
603 // used to check for CONDVAR_WAIT here, but that is now covered by
604 // the _thread_blocked with self-suspension check.
605 //
606 // Return true since we wouldn't be here unless there was still an
607 // external suspend request.
608 *bits |= 0x00001000;
609 return true;
610 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
611 // Threads running native code will self-suspend on native==>VM/Java
612 // transitions. If its stack is walkable (should always be the case
613 // unless this function is called before the actual java_suspend()
614 // call), then the wait is done.
615 *bits |= 0x00002000;
616 return true;
617 } else if (!called_by_wait && !did_trans_retry &&
618 save_state == _thread_in_native_trans &&
619 frame_anchor()->walkable()) {
620 // The thread is transitioning from thread_in_native to another
621 // thread state. check_safepoint_and_suspend_for_native_trans()
622 // will force the thread to self-suspend. If it hasn't gotten
623 // there yet we may have caught the thread in-between the native
624 // code check above and the self-suspend. Lucky us. If we were
625 // called by wait_for_ext_suspend_completion(), then it
626 // will be doing the retries so we don't have to.
627 //
628 // Since we use the saved thread state in the if-statement above,
629 // there is a chance that the thread has already transitioned to
630 // _thread_blocked by the time we get here. In that case, we will
631 // make a single unnecessary pass through the logic below. This
632 // doesn't hurt anything since we still do the trans retry.
633
634 *bits |= 0x00004000;
635
636 // Once the thread leaves thread_in_native_trans for another
637 // thread state, we break out of this retry loop. We shouldn't
638 // need this flag to prevent us from getting back here, but
639 // sometimes paranoia is good.
640 did_trans_retry = true;
641
642 // We wait for the thread to transition to a more usable state.
643 for (int i = 1; i <= SuspendRetryCount; i++) {
644 // We used to do an "os::yield_all(i)" call here with the intention
645 // that yielding would increase on each retry. However, the parameter
646 // is ignored on Linux which means the yield didn't scale up. Waiting
647 // on the SR_lock below provides a much more predictable scale up for
648 // the delay. It also provides a simple/direct point to check for any
649 // safepoint requests from the VMThread
650
651 // temporarily drops SR_lock while doing wait with safepoint check
652 // (if we're a JavaThread - the WatcherThread can also call this)
653 // and increase delay with each retry
654 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
655
656 // check the actual thread state instead of what we saved above
657 if (thread_state() != _thread_in_native_trans) {
658 // the thread has transitioned to another thread state so
659 // try all the checks (except this one) one more time.
660 do_trans_retry = true;
661 break;
662 }
663 } // end retry loop
664
665
666 }
667 } while (do_trans_retry);
668
669 *bits |= 0x00000010;
670 return false;
671 }
672
673 //
674 // Wait for an external suspend request to complete (or be cancelled).
675 // Returns true if the thread is externally suspended and false otherwise.
676 //
677 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
678 uint32_t *bits) {
679 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
680 false /* !called_by_wait */, bits);
681
682 // local flag copies to minimize SR_lock hold time
683 bool is_suspended;
684 bool pending;
685 uint32_t reset_bits;
686
687 // set a marker so is_ext_suspend_completed() knows we are the caller
688 *bits |= 0x00010000;
689
690 // We use reset_bits to reinitialize the bits value at the top of
691 // each retry loop. This allows the caller to make use of any
692 // unused bits for their own marking purposes.
693 reset_bits = *bits;
694
695 {
696 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
697 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
698 delay, bits);
699 pending = is_external_suspend();
700 }
701 // must release SR_lock to allow suspension to complete
702
703 if (!pending) {
704 // A cancelled suspend request is the only false return from
705 // is_ext_suspend_completed() that keeps us from entering the
706 // retry loop.
707 *bits |= 0x00020000;
708 return false;
709 }
710
711 if (is_suspended) {
712 *bits |= 0x00040000;
713 return true;
714 }
715
716 for (int i = 1; i <= retries; i++) {
717 *bits = reset_bits; // reinit to only track last retry
718
719 // We used to do an "os::yield_all(i)" call here with the intention
720 // that yielding would increase on each retry. However, the parameter
721 // is ignored on Linux which means the yield didn't scale up. Waiting
722 // on the SR_lock below provides a much more predictable scale up for
723 // the delay. It also provides a simple/direct point to check for any
724 // safepoint requests from the VMThread
725
726 {
727 MutexLocker ml(SR_lock());
728 // wait with safepoint check (if we're a JavaThread - the WatcherThread
729 // can also call this) and increase delay with each retry
730 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
731
732 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
733 delay, bits);
734
735 // It is possible for the external suspend request to be cancelled
736 // (by a resume) before the actual suspend operation is completed.
737 // Refresh our local copy to see if we still need to wait.
738 pending = is_external_suspend();
739 }
740
741 if (!pending) {
742 // A cancelled suspend request is the only false return from
743 // is_ext_suspend_completed() that keeps us from staying in the
744 // retry loop.
745 *bits |= 0x00080000;
746 return false;
747 }
748
749 if (is_suspended) {
750 *bits |= 0x00100000;
751 return true;
752 }
753 } // end retry loop
754
755 // thread did not suspend after all our retries
756 *bits |= 0x00200000;
757 return false;
758 }
759
760 #ifndef PRODUCT
761 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
762
763 // This should not need to be atomic as the only way for simultaneous
764 // updates is via interrupts. Even then this should be rare or non-existant
765 // and we don't care that much anyway.
766
767 int index = _jmp_ring_index;
768 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
769 _jmp_ring[index]._target = (intptr_t) target;
770 _jmp_ring[index]._instruction = (intptr_t) instr;
771 _jmp_ring[index]._file = file;
772 _jmp_ring[index]._line = line;
773 }
774 #endif /* PRODUCT */
775
776 // Called by flat profiler
777 // Callers have already called wait_for_ext_suspend_completion
778 // The assertion for that is currently too complex to put here:
779 bool JavaThread::profile_last_Java_frame(frame* _fr) {
780 bool gotframe = false;
781 // self suspension saves needed state.
782 if (has_last_Java_frame() && _anchor.walkable()) {
783 *_fr = pd_last_frame();
784 gotframe = true;
785 }
786 return gotframe;
787 }
788
789 void Thread::interrupt(Thread* thread) {
790 trace("interrupt", thread);
791 debug_only(check_for_dangling_thread_pointer(thread);)
792 os::interrupt(thread);
793 }
794
795 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
796 trace("is_interrupted", thread);
797 debug_only(check_for_dangling_thread_pointer(thread);)
798 // Note: If clear_interrupted==false, this simply fetches and
799 // returns the value of the field osthread()->interrupted().
800 return os::is_interrupted(thread, clear_interrupted);
801 }
802
803
804 // GC Support
805 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
806 jint thread_parity = _oops_do_parity;
807 if (thread_parity != strong_roots_parity) {
808 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
809 if (res == thread_parity) {
810 return true;
811 } else {
812 guarantee(res == strong_roots_parity, "Or else what?");
813 assert(SharedHeap::heap()->workers()->active_workers() > 0,
814 "Should only fail when parallel.");
815 return false;
816 }
817 }
818 assert(SharedHeap::heap()->workers()->active_workers() > 0,
819 "Should only fail when parallel.");
820 return false;
821 }
822
823 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
824 active_handles()->oops_do(f);
825 // Do oop for ThreadShadow
826 f->do_oop((oop*)&_pending_exception);
827 handle_area()->oops_do(f);
828 }
829
830 void Thread::nmethods_do(CodeBlobClosure* cf) {
831 // no nmethods in a generic thread...
832 }
833
834 void Thread::print_on(outputStream* st) const {
835 // get_priority assumes osthread initialized
836 if (osthread() != NULL) {
837 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
838 osthread()->print_on(st);
839 }
840 debug_only(if (WizardMode) print_owned_locks_on(st);)
841 }
842
843 // Thread::print_on_error() is called by fatal error handler. Don't use
844 // any lock or allocate memory.
845 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
846 if (is_VM_thread()) st->print("VMThread");
847 else if (is_Compiler_thread()) st->print("CompilerThread");
848 else if (is_Java_thread()) st->print("JavaThread");
849 else if (is_GC_task_thread()) st->print("GCTaskThread");
850 else if (is_Watcher_thread()) st->print("WatcherThread");
851 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
852 else st->print("Thread");
853
854 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
855 _stack_base - _stack_size, _stack_base);
856
857 if (osthread()) {
858 st->print(" [id=%d]", osthread()->thread_id());
859 }
860 }
861
862 #ifdef ASSERT
863 void Thread::print_owned_locks_on(outputStream* st) const {
864 Monitor *cur = _owned_locks;
865 if (cur == NULL) {
866 st->print(" (no locks) ");
867 } else {
868 st->print_cr(" Locks owned:");
869 while(cur) {
870 cur->print_on(st);
871 cur = cur->next();
872 }
873 }
874 }
875
876 static int ref_use_count = 0;
877
878 bool Thread::owns_locks_but_compiled_lock() const {
879 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
880 if (cur != Compile_lock) return true;
881 }
882 return false;
883 }
884
885
886 #endif
887
888 #ifndef PRODUCT
889
890 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
891 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
892 // no threads which allow_vm_block's are held
893 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
894 // Check if current thread is allowed to block at a safepoint
895 if (!(_allow_safepoint_count == 0))
896 fatal("Possible safepoint reached by thread that does not allow it");
897 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
898 fatal("LEAF method calling lock?");
899 }
900
901 #ifdef ASSERT
902 if (potential_vm_operation && is_Java_thread()
903 && !Universe::is_bootstrapping()) {
904 // Make sure we do not hold any locks that the VM thread also uses.
905 // This could potentially lead to deadlocks
906 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
907 // Threads_lock is special, since the safepoint synchronization will not start before this is
908 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
909 // since it is used to transfer control between JavaThreads and the VMThread
910 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
911 if ( (cur->allow_vm_block() &&
912 cur != Threads_lock &&
913 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
914 cur != VMOperationRequest_lock &&
915 cur != VMOperationQueue_lock) ||
916 cur->rank() == Mutex::special) {
917 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
918 }
919 }
920 }
921
922 if (GCALotAtAllSafepoints) {
923 // We could enter a safepoint here and thus have a gc
924 InterfaceSupport::check_gc_alot();
925 }
926 #endif
927 }
928 #endif
929
930 bool Thread::is_in_stack(address adr) const {
931 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
932 address end = os::current_stack_pointer();
933 if (stack_base() >= adr && adr >= end) return true;
934
935 return false;
936 }
937
938
939 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
940 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
941 // used for compilation in the future. If that change is made, the need for these methods
942 // should be revisited, and they should be removed if possible.
943
944 bool Thread::is_lock_owned(address adr) const {
945 return on_local_stack(adr);
946 }
947
948 bool Thread::set_as_starting_thread() {
949 // NOTE: this must be called inside the main thread.
950 return os::create_main_thread((JavaThread*)this);
951 }
952
953 static void initialize_class(Symbol* class_name, TRAPS) {
954 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
955 instanceKlass::cast(klass)->initialize(CHECK);
956 }
957
958
959 // Creates the initial ThreadGroup
960 static Handle create_initial_thread_group(TRAPS) {
961 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
962 instanceKlassHandle klass (THREAD, k);
963
964 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
965 {
966 JavaValue result(T_VOID);
967 JavaCalls::call_special(&result,
968 system_instance,
969 klass,
970 vmSymbols::object_initializer_name(),
971 vmSymbols::void_method_signature(),
972 CHECK_NH);
973 }
974 Universe::set_system_thread_group(system_instance());
975
976 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
977 {
978 JavaValue result(T_VOID);
979 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
980 JavaCalls::call_special(&result,
981 main_instance,
982 klass,
983 vmSymbols::object_initializer_name(),
984 vmSymbols::threadgroup_string_void_signature(),
985 system_instance,
986 string,
987 CHECK_NH);
988 }
989 return main_instance;
990 }
991
992 // Creates the initial Thread
993 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
994 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
995 instanceKlassHandle klass (THREAD, k);
996 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
997
998 java_lang_Thread::set_thread(thread_oop(), thread);
999 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1000 thread->set_threadObj(thread_oop());
1001
1002 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1003
1004 JavaValue result(T_VOID);
1005 JavaCalls::call_special(&result, thread_oop,
1006 klass,
1007 vmSymbols::object_initializer_name(),
1008 vmSymbols::threadgroup_string_void_signature(),
1009 thread_group,
1010 string,
1011 CHECK_NULL);
1012 return thread_oop();
1013 }
1014
1015 static void call_initializeSystemClass(TRAPS) {
1016 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1017 instanceKlassHandle klass (THREAD, k);
1018
1019 JavaValue result(T_VOID);
1020 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1021 vmSymbols::void_method_signature(), CHECK);
1022 }
1023
1024 char java_runtime_name[128] = "";
1025 char java_runtime_version[128] = "";
1026
1027 // extract the JRE name from sun.misc.Version.java_runtime_name
1028 static const char* get_java_runtime_name(TRAPS) {
1029 klassOop k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1030 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1031 fieldDescriptor fd;
1032 bool found = k != NULL &&
1033 instanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1034 vmSymbols::string_signature(), &fd);
1035 if (found) {
1036 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1037 if (name_oop == NULL)
1038 return NULL;
1039 const char* name = java_lang_String::as_utf8_string(name_oop,
1040 java_runtime_name,
1041 sizeof(java_runtime_name));
1042 return name;
1043 } else {
1044 return NULL;
1045 }
1046 }
1047
1048 // extract the JRE version from sun.misc.Version.java_runtime_version
1049 static const char* get_java_runtime_version(TRAPS) {
1050 klassOop k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1051 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1052 fieldDescriptor fd;
1053 bool found = k != NULL &&
1054 instanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1055 vmSymbols::string_signature(), &fd);
1056 if (found) {
1057 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1058 if (name_oop == NULL)
1059 return NULL;
1060 const char* name = java_lang_String::as_utf8_string(name_oop,
1061 java_runtime_version,
1062 sizeof(java_runtime_version));
1063 return name;
1064 } else {
1065 return NULL;
1066 }
1067 }
1068
1069 // General purpose hook into Java code, run once when the VM is initialized.
1070 // The Java library method itself may be changed independently from the VM.
1071 static void call_postVMInitHook(TRAPS) {
1072 klassOop k = SystemDictionary::PostVMInitHook_klass();
1073 instanceKlassHandle klass (THREAD, k);
1074 if (klass.not_null()) {
1075 JavaValue result(T_VOID);
1076 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1077 vmSymbols::void_method_signature(),
1078 CHECK);
1079 }
1080 }
1081
1082 static void reset_vm_info_property(TRAPS) {
1083 // the vm info string
1084 ResourceMark rm(THREAD);
1085 const char *vm_info = VM_Version::vm_info_string();
1086
1087 // java.lang.System class
1088 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1089 instanceKlassHandle klass (THREAD, k);
1090
1091 // setProperty arguments
1092 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1093 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1094
1095 // return value
1096 JavaValue r(T_OBJECT);
1097
1098 // public static String setProperty(String key, String value);
1099 JavaCalls::call_static(&r,
1100 klass,
1101 vmSymbols::setProperty_name(),
1102 vmSymbols::string_string_string_signature(),
1103 key_str,
1104 value_str,
1105 CHECK);
1106 }
1107
1108
1109 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1110 assert(thread_group.not_null(), "thread group should be specified");
1111 assert(threadObj() == NULL, "should only create Java thread object once");
1112
1113 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1114 instanceKlassHandle klass (THREAD, k);
1115 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1116
1117 java_lang_Thread::set_thread(thread_oop(), this);
1118 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1119 set_threadObj(thread_oop());
1120
1121 JavaValue result(T_VOID);
1122 if (thread_name != NULL) {
1123 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1124 // Thread gets assigned specified name and null target
1125 JavaCalls::call_special(&result,
1126 thread_oop,
1127 klass,
1128 vmSymbols::object_initializer_name(),
1129 vmSymbols::threadgroup_string_void_signature(),
1130 thread_group, // Argument 1
1131 name, // Argument 2
1132 THREAD);
1133 } else {
1134 // Thread gets assigned name "Thread-nnn" and null target
1135 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1136 JavaCalls::call_special(&result,
1137 thread_oop,
1138 klass,
1139 vmSymbols::object_initializer_name(),
1140 vmSymbols::threadgroup_runnable_void_signature(),
1141 thread_group, // Argument 1
1142 Handle(), // Argument 2
1143 THREAD);
1144 }
1145
1146
1147 if (daemon) {
1148 java_lang_Thread::set_daemon(thread_oop());
1149 }
1150
1151 if (HAS_PENDING_EXCEPTION) {
1152 return;
1153 }
1154
1155 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1156 Handle threadObj(this, this->threadObj());
1157
1158 JavaCalls::call_special(&result,
1159 thread_group,
1160 group,
1161 vmSymbols::add_method_name(),
1162 vmSymbols::thread_void_signature(),
1163 threadObj, // Arg 1
1164 THREAD);
1165
1166
1167 }
1168
1169 // NamedThread -- non-JavaThread subclasses with multiple
1170 // uniquely named instances should derive from this.
1171 NamedThread::NamedThread() : Thread() {
1172 _name = NULL;
1173 _processed_thread = NULL;
1174 }
1175
1176 NamedThread::~NamedThread() {
1177 if (_name != NULL) {
1178 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1179 _name = NULL;
1180 }
1181 }
1182
1183 void NamedThread::set_name(const char* format, ...) {
1184 guarantee(_name == NULL, "Only get to set name once.");
1185 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1186 guarantee(_name != NULL, "alloc failure");
1187 va_list ap;
1188 va_start(ap, format);
1189 jio_vsnprintf(_name, max_name_len, format, ap);
1190 va_end(ap);
1191 }
1192
1193 // ======= WatcherThread ========
1194
1195 // The watcher thread exists to simulate timer interrupts. It should
1196 // be replaced by an abstraction over whatever native support for
1197 // timer interrupts exists on the platform.
1198
1199 WatcherThread* WatcherThread::_watcher_thread = NULL;
1200 bool WatcherThread::_startable = false;
1201 volatile bool WatcherThread::_should_terminate = false;
1202
1203 WatcherThread::WatcherThread() : Thread() {
1204 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1205 if (os::create_thread(this, os::watcher_thread)) {
1206 _watcher_thread = this;
1207
1208 // Set the watcher thread to the highest OS priority which should not be
1209 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1210 // is created. The only normal thread using this priority is the reference
1211 // handler thread, which runs for very short intervals only.
1212 // If the VMThread's priority is not lower than the WatcherThread profiling
1213 // will be inaccurate.
1214 os::set_priority(this, MaxPriority);
1215 if (!DisableStartThread) {
1216 os::start_thread(this);
1217 }
1218 }
1219 }
1220
1221 int WatcherThread::sleep() const {
1222 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1223
1224 // remaining will be zero if there are no tasks,
1225 // causing the WatcherThread to sleep until a task is
1226 // enrolled
1227 int remaining = PeriodicTask::time_to_wait();
1228 int time_slept = 0;
1229
1230 // we expect this to timeout - we only ever get unparked when
1231 // we should terminate or when a new task has been enrolled
1232 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1233
1234 jlong time_before_loop = os::javaTimeNanos();
1235
1236 for (;;) {
1237 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1238 jlong now = os::javaTimeNanos();
1239
1240 if (remaining == 0) {
1241 // if we didn't have any tasks we could have waited for a long time
1242 // consider the time_slept zero and reset time_before_loop
1243 time_slept = 0;
1244 time_before_loop = now;
1245 } else {
1246 // need to recalulate since we might have new tasks in _tasks
1247 time_slept = (int) ((now - time_before_loop) / 1000000);
1248 }
1249
1250 // Change to task list or spurious wakeup of some kind
1251 if (timedout || _should_terminate) {
1252 break;
1253 }
1254
1255 remaining = PeriodicTask::time_to_wait();
1256 if (remaining == 0) {
1257 // Last task was just disenrolled so loop around and wait until
1258 // another task gets enrolled
1259 continue;
1260 }
1261
1262 remaining -= time_slept;
1263 if (remaining <= 0)
1264 break;
1265 }
1266
1267 return time_slept;
1268 }
1269
1270 void WatcherThread::run() {
1271 assert(this == watcher_thread(), "just checking");
1272
1273 this->record_stack_base_and_size();
1274 this->initialize_thread_local_storage();
1275 this->set_active_handles(JNIHandleBlock::allocate_block());
1276 while(!_should_terminate) {
1277 assert(watcher_thread() == Thread::current(), "thread consistency check");
1278 assert(watcher_thread() == this, "thread consistency check");
1279
1280 // Calculate how long it'll be until the next PeriodicTask work
1281 // should be done, and sleep that amount of time.
1282 int time_waited = sleep();
1283
1284 if (is_error_reported()) {
1285 // A fatal error has happened, the error handler(VMError::report_and_die)
1286 // should abort JVM after creating an error log file. However in some
1287 // rare cases, the error handler itself might deadlock. Here we try to
1288 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1289 //
1290 // This code is in WatcherThread because WatcherThread wakes up
1291 // periodically so the fatal error handler doesn't need to do anything;
1292 // also because the WatcherThread is less likely to crash than other
1293 // threads.
1294
1295 for (;;) {
1296 if (!ShowMessageBoxOnError
1297 && (OnError == NULL || OnError[0] == '\0')
1298 && Arguments::abort_hook() == NULL) {
1299 os::sleep(this, 2 * 60 * 1000, false);
1300 fdStream err(defaultStream::output_fd());
1301 err.print_raw_cr("# [ timer expired, abort... ]");
1302 // skip atexit/vm_exit/vm_abort hooks
1303 os::die();
1304 }
1305
1306 // Wake up 5 seconds later, the fatal handler may reset OnError or
1307 // ShowMessageBoxOnError when it is ready to abort.
1308 os::sleep(this, 5 * 1000, false);
1309 }
1310 }
1311
1312 PeriodicTask::real_time_tick(time_waited);
1313 }
1314
1315 // Signal that it is terminated
1316 {
1317 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1318 _watcher_thread = NULL;
1319 Terminator_lock->notify();
1320 }
1321
1322 // Thread destructor usually does this..
1323 ThreadLocalStorage::set_thread(NULL);
1324 }
1325
1326 void WatcherThread::start() {
1327 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1328
1329 if (watcher_thread() == NULL && _startable) {
1330 _should_terminate = false;
1331 // Create the single instance of WatcherThread
1332 new WatcherThread();
1333 }
1334 }
1335
1336 void WatcherThread::make_startable() {
1337 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1338 _startable = true;
1339 }
1340
1341 void WatcherThread::stop() {
1342 {
1343 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1344 _should_terminate = true;
1345 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1346
1347 WatcherThread* watcher = watcher_thread();
1348 if (watcher != NULL)
1349 watcher->unpark();
1350 }
1351
1352 // it is ok to take late safepoints here, if needed
1353 MutexLocker mu(Terminator_lock);
1354
1355 while(watcher_thread() != NULL) {
1356 // This wait should make safepoint checks, wait without a timeout,
1357 // and wait as a suspend-equivalent condition.
1358 //
1359 // Note: If the FlatProfiler is running, then this thread is waiting
1360 // for the WatcherThread to terminate and the WatcherThread, via the
1361 // FlatProfiler task, is waiting for the external suspend request on
1362 // this thread to complete. wait_for_ext_suspend_completion() will
1363 // eventually timeout, but that takes time. Making this wait a
1364 // suspend-equivalent condition solves that timeout problem.
1365 //
1366 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1367 Mutex::_as_suspend_equivalent_flag);
1368 }
1369 }
1370
1371 void WatcherThread::unpark() {
1372 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1373 PeriodicTask_lock->notify();
1374 }
1375
1376 void WatcherThread::print_on(outputStream* st) const {
1377 st->print("\"%s\" ", name());
1378 Thread::print_on(st);
1379 st->cr();
1380 }
1381
1382 // ======= JavaThread ========
1383
1384 // A JavaThread is a normal Java thread
1385
1386 void JavaThread::initialize() {
1387 // Initialize fields
1388
1389 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1390 set_claimed_par_id(-1);
1391
1392 set_saved_exception_pc(NULL);
1393 set_threadObj(NULL);
1394 _anchor.clear();
1395 set_entry_point(NULL);
1396 set_jni_functions(jni_functions());
1397 set_callee_target(NULL);
1398 set_vm_result(NULL);
1399 set_vm_result_2(NULL);
1400 set_vframe_array_head(NULL);
1401 set_vframe_array_last(NULL);
1402 set_deferred_locals(NULL);
1403 set_deopt_mark(NULL);
1404 set_deopt_nmethod(NULL);
1405 clear_must_deopt_id();
1406 set_monitor_chunks(NULL);
1407 set_next(NULL);
1408 set_thread_state(_thread_new);
1409 set_recorder(NULL);
1410 _terminated = _not_terminated;
1411 _privileged_stack_top = NULL;
1412 _array_for_gc = NULL;
1413 _suspend_equivalent = false;
1414 _in_deopt_handler = 0;
1415 _doing_unsafe_access = false;
1416 _stack_guard_state = stack_guard_unused;
1417 _exception_oop = NULL;
1418 _exception_pc = 0;
1419 _exception_handler_pc = 0;
1420 _is_method_handle_return = 0;
1421 _jvmti_thread_state= NULL;
1422 _should_post_on_exceptions_flag = JNI_FALSE;
1423 _jvmti_get_loaded_classes_closure = NULL;
1424 _interp_only_mode = 0;
1425 _special_runtime_exit_condition = _no_async_condition;
1426 _pending_async_exception = NULL;
1427 _is_compiling = false;
1428 _thread_stat = NULL;
1429 _thread_stat = new ThreadStatistics();
1430 _blocked_on_compilation = false;
1431 _jni_active_critical = 0;
1432 _do_not_unlock_if_synchronized = false;
1433 _cached_monitor_info = NULL;
1434 _parker = Parker::Allocate(this) ;
1435
1436 #ifndef PRODUCT
1437 _jmp_ring_index = 0;
1438 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1439 record_jump(NULL, NULL, NULL, 0);
1440 }
1441 #endif /* PRODUCT */
1442
1443 set_thread_profiler(NULL);
1444 if (FlatProfiler::is_active()) {
1445 // This is where we would decide to either give each thread it's own profiler
1446 // or use one global one from FlatProfiler,
1447 // or up to some count of the number of profiled threads, etc.
1448 ThreadProfiler* pp = new ThreadProfiler();
1449 pp->engage();
1450 set_thread_profiler(pp);
1451 }
1452
1453 // Setup safepoint state info for this thread
1454 ThreadSafepointState::create(this);
1455
1456 debug_only(_java_call_counter = 0);
1457
1458 // JVMTI PopFrame support
1459 _popframe_condition = popframe_inactive;
1460 _popframe_preserved_args = NULL;
1461 _popframe_preserved_args_size = 0;
1462
1463 pd_initialize();
1464 }
1465
1466 #ifndef SERIALGC
1467 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1468 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1469 #endif // !SERIALGC
1470
1471 JavaThread::JavaThread(bool is_attaching_via_jni) :
1472 Thread()
1473 #ifndef SERIALGC
1474 , _satb_mark_queue(&_satb_mark_queue_set),
1475 _dirty_card_queue(&_dirty_card_queue_set)
1476 #endif // !SERIALGC
1477 {
1478 initialize();
1479 if (is_attaching_via_jni) {
1480 _jni_attach_state = _attaching_via_jni;
1481 } else {
1482 _jni_attach_state = _not_attaching_via_jni;
1483 }
1484 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1485 _safepoint_visible = false;
1486 }
1487
1488 bool JavaThread::reguard_stack(address cur_sp) {
1489 if (_stack_guard_state != stack_guard_yellow_disabled) {
1490 return true; // Stack already guarded or guard pages not needed.
1491 }
1492
1493 if (register_stack_overflow()) {
1494 // For those architectures which have separate register and
1495 // memory stacks, we must check the register stack to see if
1496 // it has overflowed.
1497 return false;
1498 }
1499
1500 // Java code never executes within the yellow zone: the latter is only
1501 // there to provoke an exception during stack banging. If java code
1502 // is executing there, either StackShadowPages should be larger, or
1503 // some exception code in c1, c2 or the interpreter isn't unwinding
1504 // when it should.
1505 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1506
1507 enable_stack_yellow_zone();
1508 return true;
1509 }
1510
1511 bool JavaThread::reguard_stack(void) {
1512 return reguard_stack(os::current_stack_pointer());
1513 }
1514
1515
1516 void JavaThread::block_if_vm_exited() {
1517 if (_terminated == _vm_exited) {
1518 // _vm_exited is set at safepoint, and Threads_lock is never released
1519 // we will block here forever
1520 Threads_lock->lock_without_safepoint_check();
1521 ShouldNotReachHere();
1522 }
1523 }
1524
1525
1526 // Remove this ifdef when C1 is ported to the compiler interface.
1527 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1528
1529 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1530 Thread()
1531 #ifndef SERIALGC
1532 , _satb_mark_queue(&_satb_mark_queue_set),
1533 _dirty_card_queue(&_dirty_card_queue_set)
1534 #endif // !SERIALGC
1535 {
1536 if (TraceThreadEvents) {
1537 tty->print_cr("creating thread %p", this);
1538 }
1539 initialize();
1540 _jni_attach_state = _not_attaching_via_jni;
1541 set_entry_point(entry_point);
1542 // Create the native thread itself.
1543 // %note runtime_23
1544 os::ThreadType thr_type = os::java_thread;
1545 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1546 os::java_thread;
1547 os::create_thread(this, thr_type, stack_sz);
1548 _safepoint_visible = false;
1549 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1550 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1551 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1552 // the exception consists of creating the exception object & initializing it, initialization
1553 // will leave the VM via a JavaCall and then all locks must be unlocked).
1554 //
1555 // The thread is still suspended when we reach here. Thread must be explicit started
1556 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1557 // by calling Threads:add. The reason why this is not done here, is because the thread
1558 // object must be fully initialized (take a look at JVM_Start)
1559 }
1560
1561 JavaThread::~JavaThread() {
1562 if (TraceThreadEvents) {
1563 tty->print_cr("terminate thread %p", this);
1564 }
1565
1566 // By now, this thread should already be invisible to safepoint,
1567 // and its per-thread recorder also collected.
1568 assert(!is_safepoint_visible(), "wrong state");
1569 #if INCLUDE_NMT
1570 assert(get_recorder() == NULL, "Already collected");
1571 #endif // INCLUDE_NMT
1572
1573 // JSR166 -- return the parker to the free list
1574 Parker::Release(_parker);
1575 _parker = NULL ;
1576
1577 // Free any remaining previous UnrollBlock
1578 vframeArray* old_array = vframe_array_last();
1579
1580 if (old_array != NULL) {
1581 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1582 old_array->set_unroll_block(NULL);
1583 delete old_info;
1584 delete old_array;
1585 }
1586
1587 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1588 if (deferred != NULL) {
1589 // This can only happen if thread is destroyed before deoptimization occurs.
1590 assert(deferred->length() != 0, "empty array!");
1591 do {
1592 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1593 deferred->remove_at(0);
1594 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1595 delete dlv;
1596 } while (deferred->length() != 0);
1597 delete deferred;
1598 }
1599
1600 // All Java related clean up happens in exit
1601 ThreadSafepointState::destroy(this);
1602 if (_thread_profiler != NULL) delete _thread_profiler;
1603 if (_thread_stat != NULL) delete _thread_stat;
1604 }
1605
1606
1607 // The first routine called by a new Java thread
1608 void JavaThread::run() {
1609 // initialize thread-local alloc buffer related fields
1610 this->initialize_tlab();
1611
1612 // used to test validitity of stack trace backs
1613 this->record_base_of_stack_pointer();
1614
1615 // Record real stack base and size.
1616 this->record_stack_base_and_size();
1617
1618 // Initialize thread local storage; set before calling MutexLocker
1619 this->initialize_thread_local_storage();
1620
1621 this->create_stack_guard_pages();
1622
1623 this->cache_global_variables();
1624
1625 // Thread is now sufficient initialized to be handled by the safepoint code as being
1626 // in the VM. Change thread state from _thread_new to _thread_in_vm
1627 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1628
1629 assert(JavaThread::current() == this, "sanity check");
1630 assert(!Thread::current()->owns_locks(), "sanity check");
1631
1632 DTRACE_THREAD_PROBE(start, this);
1633
1634 // This operation might block. We call that after all safepoint checks for a new thread has
1635 // been completed.
1636 this->set_active_handles(JNIHandleBlock::allocate_block());
1637
1638 if (JvmtiExport::should_post_thread_life()) {
1639 JvmtiExport::post_thread_start(this);
1640 }
1641
1642 EventThreadStart event;
1643 if (event.should_commit()) {
1644 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1645 event.commit();
1646 }
1647
1648 // We call another function to do the rest so we are sure that the stack addresses used
1649 // from there will be lower than the stack base just computed
1650 thread_main_inner();
1651
1652 // Note, thread is no longer valid at this point!
1653 }
1654
1655
1656 void JavaThread::thread_main_inner() {
1657 assert(JavaThread::current() == this, "sanity check");
1658 assert(this->threadObj() != NULL, "just checking");
1659
1660 // Execute thread entry point unless this thread has a pending exception
1661 // or has been stopped before starting.
1662 // Note: Due to JVM_StopThread we can have pending exceptions already!
1663 if (!this->has_pending_exception() &&
1664 !java_lang_Thread::is_stillborn(this->threadObj())) {
1665 {
1666 ResourceMark rm(this);
1667 this->set_native_thread_name(this->get_thread_name());
1668 }
1669 HandleMark hm(this);
1670 this->entry_point()(this, this);
1671 }
1672
1673 DTRACE_THREAD_PROBE(stop, this);
1674
1675 this->exit(false);
1676 delete this;
1677 }
1678
1679
1680 static void ensure_join(JavaThread* thread) {
1681 // We do not need to grap the Threads_lock, since we are operating on ourself.
1682 Handle threadObj(thread, thread->threadObj());
1683 assert(threadObj.not_null(), "java thread object must exist");
1684 ObjectLocker lock(threadObj, thread);
1685 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1686 thread->clear_pending_exception();
1687 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1688 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1689 // Clear the native thread instance - this makes isAlive return false and allows the join()
1690 // to complete once we've done the notify_all below
1691 java_lang_Thread::set_thread(threadObj(), NULL);
1692 lock.notify_all(thread);
1693 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1694 thread->clear_pending_exception();
1695 }
1696
1697
1698 // For any new cleanup additions, please check to see if they need to be applied to
1699 // cleanup_failed_attach_current_thread as well.
1700 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1701 assert(this == JavaThread::current(), "thread consistency check");
1702 if (!InitializeJavaLangSystem) return;
1703
1704 HandleMark hm(this);
1705 Handle uncaught_exception(this, this->pending_exception());
1706 this->clear_pending_exception();
1707 Handle threadObj(this, this->threadObj());
1708 assert(threadObj.not_null(), "Java thread object should be created");
1709
1710 if (get_thread_profiler() != NULL) {
1711 get_thread_profiler()->disengage();
1712 ResourceMark rm;
1713 get_thread_profiler()->print(get_thread_name());
1714 }
1715
1716
1717 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1718 {
1719 EXCEPTION_MARK;
1720
1721 CLEAR_PENDING_EXCEPTION;
1722 }
1723 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1724 // has to be fixed by a runtime query method
1725 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1726 // JSR-166: change call from from ThreadGroup.uncaughtException to
1727 // java.lang.Thread.dispatchUncaughtException
1728 if (uncaught_exception.not_null()) {
1729 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1730 {
1731 EXCEPTION_MARK;
1732 // Check if the method Thread.dispatchUncaughtException() exists. If so
1733 // call it. Otherwise we have an older library without the JSR-166 changes,
1734 // so call ThreadGroup.uncaughtException()
1735 KlassHandle recvrKlass(THREAD, threadObj->klass());
1736 CallInfo callinfo;
1737 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1738 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1739 vmSymbols::dispatchUncaughtException_name(),
1740 vmSymbols::throwable_void_signature(),
1741 KlassHandle(), false, false, THREAD);
1742 CLEAR_PENDING_EXCEPTION;
1743 methodHandle method = callinfo.selected_method();
1744 if (method.not_null()) {
1745 JavaValue result(T_VOID);
1746 JavaCalls::call_virtual(&result,
1747 threadObj, thread_klass,
1748 vmSymbols::dispatchUncaughtException_name(),
1749 vmSymbols::throwable_void_signature(),
1750 uncaught_exception,
1751 THREAD);
1752 } else {
1753 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1754 JavaValue result(T_VOID);
1755 JavaCalls::call_virtual(&result,
1756 group, thread_group,
1757 vmSymbols::uncaughtException_name(),
1758 vmSymbols::thread_throwable_void_signature(),
1759 threadObj, // Arg 1
1760 uncaught_exception, // Arg 2
1761 THREAD);
1762 }
1763 if (HAS_PENDING_EXCEPTION) {
1764 ResourceMark rm(this);
1765 jio_fprintf(defaultStream::error_stream(),
1766 "\nException: %s thrown from the UncaughtExceptionHandler"
1767 " in thread \"%s\"\n",
1768 Klass::cast(pending_exception()->klass())->external_name(),
1769 get_thread_name());
1770 CLEAR_PENDING_EXCEPTION;
1771 }
1772 }
1773 }
1774
1775 // Called before the java thread exit since we want to read info
1776 // from java_lang_Thread object
1777 EventThreadEnd event;
1778 if (event.should_commit()) {
1779 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1780 event.commit();
1781 }
1782
1783 // Call after last event on thread
1784 EVENT_THREAD_EXIT(this);
1785
1786 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1787 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1788 // is deprecated anyhow.
1789 { int count = 3;
1790 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1791 EXCEPTION_MARK;
1792 JavaValue result(T_VOID);
1793 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1794 JavaCalls::call_virtual(&result,
1795 threadObj, thread_klass,
1796 vmSymbols::exit_method_name(),
1797 vmSymbols::void_method_signature(),
1798 THREAD);
1799 CLEAR_PENDING_EXCEPTION;
1800 }
1801 }
1802
1803 // notify JVMTI
1804 if (JvmtiExport::should_post_thread_life()) {
1805 JvmtiExport::post_thread_end(this);
1806 }
1807
1808 // We have notified the agents that we are exiting, before we go on,
1809 // we must check for a pending external suspend request and honor it
1810 // in order to not surprise the thread that made the suspend request.
1811 while (true) {
1812 {
1813 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1814 if (!is_external_suspend()) {
1815 set_terminated(_thread_exiting);
1816 ThreadService::current_thread_exiting(this);
1817 break;
1818 }
1819 // Implied else:
1820 // Things get a little tricky here. We have a pending external
1821 // suspend request, but we are holding the SR_lock so we
1822 // can't just self-suspend. So we temporarily drop the lock
1823 // and then self-suspend.
1824 }
1825
1826 ThreadBlockInVM tbivm(this);
1827 java_suspend_self();
1828
1829 // We're done with this suspend request, but we have to loop around
1830 // and check again. Eventually we will get SR_lock without a pending
1831 // external suspend request and will be able to mark ourselves as
1832 // exiting.
1833 }
1834 // no more external suspends are allowed at this point
1835 } else {
1836 // before_exit() has already posted JVMTI THREAD_END events
1837 }
1838
1839 // Notify waiters on thread object. This has to be done after exit() is called
1840 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1841 // group should have the destroyed bit set before waiters are notified).
1842 ensure_join(this);
1843 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1844
1845 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1846 // held by this thread must be released. A detach operation must only
1847 // get here if there are no Java frames on the stack. Therefore, any
1848 // owned monitors at this point MUST be JNI-acquired monitors which are
1849 // pre-inflated and in the monitor cache.
1850 //
1851 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1852 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1853 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1854 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1855 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1856 }
1857
1858 // These things needs to be done while we are still a Java Thread. Make sure that thread
1859 // is in a consistent state, in case GC happens
1860 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1861
1862 if (active_handles() != NULL) {
1863 JNIHandleBlock* block = active_handles();
1864 set_active_handles(NULL);
1865 JNIHandleBlock::release_block(block);
1866 }
1867
1868 if (free_handle_block() != NULL) {
1869 JNIHandleBlock* block = free_handle_block();
1870 set_free_handle_block(NULL);
1871 JNIHandleBlock::release_block(block);
1872 }
1873
1874 // These have to be removed while this is still a valid thread.
1875 remove_stack_guard_pages();
1876
1877 if (UseTLAB) {
1878 tlab().make_parsable(true); // retire TLAB
1879 }
1880
1881 if (JvmtiEnv::environments_might_exist()) {
1882 JvmtiExport::cleanup_thread(this);
1883 }
1884
1885 // We must flush any deferred card marks before removing a thread from
1886 // the list of active threads.
1887 Universe::heap()->flush_deferred_store_barrier(this);
1888 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1889
1890 #ifndef SERIALGC
1891 // We must flush the G1-related buffers before removing a thread
1892 // from the list of active threads. We must do this after any deferred
1893 // card marks have been flushed (above) so that any entries that are
1894 // added to the thread's dirty card queue as a result are not lost.
1895 if (UseG1GC) {
1896 flush_barrier_queues();
1897 }
1898 #endif
1899
1900 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1901 Threads::remove(this);
1902 }
1903
1904 #ifndef SERIALGC
1905 // Flush G1-related queues.
1906 void JavaThread::flush_barrier_queues() {
1907 satb_mark_queue().flush();
1908 dirty_card_queue().flush();
1909 }
1910
1911 void JavaThread::initialize_queues() {
1912 assert(!SafepointSynchronize::is_at_safepoint(),
1913 "we should not be at a safepoint");
1914
1915 ObjPtrQueue& satb_queue = satb_mark_queue();
1916 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1917 // The SATB queue should have been constructed with its active
1918 // field set to false.
1919 assert(!satb_queue.is_active(), "SATB queue should not be active");
1920 assert(satb_queue.is_empty(), "SATB queue should be empty");
1921 // If we are creating the thread during a marking cycle, we should
1922 // set the active field of the SATB queue to true.
1923 if (satb_queue_set.is_active()) {
1924 satb_queue.set_active(true);
1925 }
1926
1927 DirtyCardQueue& dirty_queue = dirty_card_queue();
1928 // The dirty card queue should have been constructed with its
1929 // active field set to true.
1930 assert(dirty_queue.is_active(), "dirty card queue should be active");
1931 }
1932 #endif // !SERIALGC
1933
1934 void JavaThread::cleanup_failed_attach_current_thread() {
1935 if (get_thread_profiler() != NULL) {
1936 get_thread_profiler()->disengage();
1937 ResourceMark rm;
1938 get_thread_profiler()->print(get_thread_name());
1939 }
1940
1941 if (active_handles() != NULL) {
1942 JNIHandleBlock* block = active_handles();
1943 set_active_handles(NULL);
1944 JNIHandleBlock::release_block(block);
1945 }
1946
1947 if (free_handle_block() != NULL) {
1948 JNIHandleBlock* block = free_handle_block();
1949 set_free_handle_block(NULL);
1950 JNIHandleBlock::release_block(block);
1951 }
1952
1953 // These have to be removed while this is still a valid thread.
1954 remove_stack_guard_pages();
1955
1956 if (UseTLAB) {
1957 tlab().make_parsable(true); // retire TLAB, if any
1958 }
1959
1960 #ifndef SERIALGC
1961 if (UseG1GC) {
1962 flush_barrier_queues();
1963 }
1964 #endif
1965
1966 Threads::remove(this);
1967 delete this;
1968 }
1969
1970
1971
1972
1973 JavaThread* JavaThread::active() {
1974 Thread* thread = ThreadLocalStorage::thread();
1975 assert(thread != NULL, "just checking");
1976 if (thread->is_Java_thread()) {
1977 return (JavaThread*) thread;
1978 } else {
1979 assert(thread->is_VM_thread(), "this must be a vm thread");
1980 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1981 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1982 assert(ret->is_Java_thread(), "must be a Java thread");
1983 return ret;
1984 }
1985 }
1986
1987 bool JavaThread::is_lock_owned(address adr) const {
1988 if (Thread::is_lock_owned(adr)) return true;
1989
1990 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1991 if (chunk->contains(adr)) return true;
1992 }
1993
1994 return false;
1995 }
1996
1997
1998 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1999 chunk->set_next(monitor_chunks());
2000 set_monitor_chunks(chunk);
2001 }
2002
2003 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2004 guarantee(monitor_chunks() != NULL, "must be non empty");
2005 if (monitor_chunks() == chunk) {
2006 set_monitor_chunks(chunk->next());
2007 } else {
2008 MonitorChunk* prev = monitor_chunks();
2009 while (prev->next() != chunk) prev = prev->next();
2010 prev->set_next(chunk->next());
2011 }
2012 }
2013
2014 // JVM support.
2015
2016 // Note: this function shouldn't block if it's called in
2017 // _thread_in_native_trans state (such as from
2018 // check_special_condition_for_native_trans()).
2019 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2020
2021 if (has_last_Java_frame() && has_async_condition()) {
2022 // If we are at a polling page safepoint (not a poll return)
2023 // then we must defer async exception because live registers
2024 // will be clobbered by the exception path. Poll return is
2025 // ok because the call we a returning from already collides
2026 // with exception handling registers and so there is no issue.
2027 // (The exception handling path kills call result registers but
2028 // this is ok since the exception kills the result anyway).
2029
2030 if (is_at_poll_safepoint()) {
2031 // if the code we are returning to has deoptimized we must defer
2032 // the exception otherwise live registers get clobbered on the
2033 // exception path before deoptimization is able to retrieve them.
2034 //
2035 RegisterMap map(this, false);
2036 frame caller_fr = last_frame().sender(&map);
2037 assert(caller_fr.is_compiled_frame(), "what?");
2038 if (caller_fr.is_deoptimized_frame()) {
2039 if (TraceExceptions) {
2040 ResourceMark rm;
2041 tty->print_cr("deferred async exception at compiled safepoint");
2042 }
2043 return;
2044 }
2045 }
2046 }
2047
2048 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2049 if (condition == _no_async_condition) {
2050 // Conditions have changed since has_special_runtime_exit_condition()
2051 // was called:
2052 // - if we were here only because of an external suspend request,
2053 // then that was taken care of above (or cancelled) so we are done
2054 // - if we were here because of another async request, then it has
2055 // been cleared between the has_special_runtime_exit_condition()
2056 // and now so again we are done
2057 return;
2058 }
2059
2060 // Check for pending async. exception
2061 if (_pending_async_exception != NULL) {
2062 // Only overwrite an already pending exception, if it is not a threadDeath.
2063 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2064
2065 // We cannot call Exceptions::_throw(...) here because we cannot block
2066 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2067
2068 if (TraceExceptions) {
2069 ResourceMark rm;
2070 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2071 if (has_last_Java_frame() ) {
2072 frame f = last_frame();
2073 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2074 }
2075 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
2076 }
2077 _pending_async_exception = NULL;
2078 clear_has_async_exception();
2079 }
2080 }
2081
2082 if (check_unsafe_error &&
2083 condition == _async_unsafe_access_error && !has_pending_exception()) {
2084 condition = _no_async_condition; // done
2085 switch (thread_state()) {
2086 case _thread_in_vm:
2087 {
2088 JavaThread* THREAD = this;
2089 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2090 }
2091 case _thread_in_native:
2092 {
2093 ThreadInVMfromNative tiv(this);
2094 JavaThread* THREAD = this;
2095 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2096 }
2097 case _thread_in_Java:
2098 {
2099 ThreadInVMfromJava tiv(this);
2100 JavaThread* THREAD = this;
2101 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2102 }
2103 default:
2104 ShouldNotReachHere();
2105 }
2106 }
2107
2108 assert(condition == _no_async_condition || has_pending_exception() ||
2109 (!check_unsafe_error && condition == _async_unsafe_access_error),
2110 "must have handled the async condition, if no exception");
2111 }
2112
2113 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2114 //
2115 // Check for pending external suspend. Internal suspend requests do
2116 // not use handle_special_runtime_exit_condition().
2117 // If JNIEnv proxies are allowed, don't self-suspend if the target
2118 // thread is not the current thread. In older versions of jdbx, jdbx
2119 // threads could call into the VM with another thread's JNIEnv so we
2120 // can be here operating on behalf of a suspended thread (4432884).
2121 bool do_self_suspend = is_external_suspend_with_lock();
2122 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2123 //
2124 // Because thread is external suspended the safepoint code will count
2125 // thread as at a safepoint. This can be odd because we can be here
2126 // as _thread_in_Java which would normally transition to _thread_blocked
2127 // at a safepoint. We would like to mark the thread as _thread_blocked
2128 // before calling java_suspend_self like all other callers of it but
2129 // we must then observe proper safepoint protocol. (We can't leave
2130 // _thread_blocked with a safepoint in progress). However we can be
2131 // here as _thread_in_native_trans so we can't use a normal transition
2132 // constructor/destructor pair because they assert on that type of
2133 // transition. We could do something like:
2134 //
2135 // JavaThreadState state = thread_state();
2136 // set_thread_state(_thread_in_vm);
2137 // {
2138 // ThreadBlockInVM tbivm(this);
2139 // java_suspend_self()
2140 // }
2141 // set_thread_state(_thread_in_vm_trans);
2142 // if (safepoint) block;
2143 // set_thread_state(state);
2144 //
2145 // but that is pretty messy. Instead we just go with the way the
2146 // code has worked before and note that this is the only path to
2147 // java_suspend_self that doesn't put the thread in _thread_blocked
2148 // mode.
2149
2150 frame_anchor()->make_walkable(this);
2151 java_suspend_self();
2152
2153 // We might be here for reasons in addition to the self-suspend request
2154 // so check for other async requests.
2155 }
2156
2157 if (check_asyncs) {
2158 check_and_handle_async_exceptions();
2159 }
2160 }
2161
2162 void JavaThread::send_thread_stop(oop java_throwable) {
2163 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2164 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2165 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2166
2167 // Do not throw asynchronous exceptions against the compiler thread
2168 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2169 if (is_Compiler_thread()) return;
2170
2171 {
2172 // Actually throw the Throwable against the target Thread - however
2173 // only if there is no thread death exception installed already.
2174 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2175 // If the topmost frame is a runtime stub, then we are calling into
2176 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2177 // must deoptimize the caller before continuing, as the compiled exception handler table
2178 // may not be valid
2179 if (has_last_Java_frame()) {
2180 frame f = last_frame();
2181 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2182 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2183 RegisterMap reg_map(this, UseBiasedLocking);
2184 frame compiled_frame = f.sender(®_map);
2185 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2186 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2187 }
2188 }
2189 }
2190
2191 // Set async. pending exception in thread.
2192 set_pending_async_exception(java_throwable);
2193
2194 if (TraceExceptions) {
2195 ResourceMark rm;
2196 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
2197 }
2198 // for AbortVMOnException flag
2199 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
2200 }
2201 }
2202
2203
2204 // Interrupt thread so it will wake up from a potential wait()
2205 Thread::interrupt(this);
2206 }
2207
2208 // External suspension mechanism.
2209 //
2210 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2211 // to any VM_locks and it is at a transition
2212 // Self-suspension will happen on the transition out of the vm.
2213 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2214 //
2215 // Guarantees on return:
2216 // + Target thread will not execute any new bytecode (that's why we need to
2217 // force a safepoint)
2218 // + Target thread will not enter any new monitors
2219 //
2220 void JavaThread::java_suspend() {
2221 { MutexLocker mu(Threads_lock);
2222 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2223 return;
2224 }
2225 }
2226
2227 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2228 if (!is_external_suspend()) {
2229 // a racing resume has cancelled us; bail out now
2230 return;
2231 }
2232
2233 // suspend is done
2234 uint32_t debug_bits = 0;
2235 // Warning: is_ext_suspend_completed() may temporarily drop the
2236 // SR_lock to allow the thread to reach a stable thread state if
2237 // it is currently in a transient thread state.
2238 if (is_ext_suspend_completed(false /* !called_by_wait */,
2239 SuspendRetryDelay, &debug_bits) ) {
2240 return;
2241 }
2242 }
2243
2244 VM_ForceSafepoint vm_suspend;
2245 VMThread::execute(&vm_suspend);
2246 }
2247
2248 // Part II of external suspension.
2249 // A JavaThread self suspends when it detects a pending external suspend
2250 // request. This is usually on transitions. It is also done in places
2251 // where continuing to the next transition would surprise the caller,
2252 // e.g., monitor entry.
2253 //
2254 // Returns the number of times that the thread self-suspended.
2255 //
2256 // Note: DO NOT call java_suspend_self() when you just want to block current
2257 // thread. java_suspend_self() is the second stage of cooperative
2258 // suspension for external suspend requests and should only be used
2259 // to complete an external suspend request.
2260 //
2261 int JavaThread::java_suspend_self() {
2262 int ret = 0;
2263
2264 // we are in the process of exiting so don't suspend
2265 if (is_exiting()) {
2266 clear_external_suspend();
2267 return ret;
2268 }
2269
2270 assert(_anchor.walkable() ||
2271 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2272 "must have walkable stack");
2273
2274 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2275
2276 assert(!this->is_ext_suspended(),
2277 "a thread trying to self-suspend should not already be suspended");
2278
2279 if (this->is_suspend_equivalent()) {
2280 // If we are self-suspending as a result of the lifting of a
2281 // suspend equivalent condition, then the suspend_equivalent
2282 // flag is not cleared until we set the ext_suspended flag so
2283 // that wait_for_ext_suspend_completion() returns consistent
2284 // results.
2285 this->clear_suspend_equivalent();
2286 }
2287
2288 // A racing resume may have cancelled us before we grabbed SR_lock
2289 // above. Or another external suspend request could be waiting for us
2290 // by the time we return from SR_lock()->wait(). The thread
2291 // that requested the suspension may already be trying to walk our
2292 // stack and if we return now, we can change the stack out from under
2293 // it. This would be a "bad thing (TM)" and cause the stack walker
2294 // to crash. We stay self-suspended until there are no more pending
2295 // external suspend requests.
2296 while (is_external_suspend()) {
2297 ret++;
2298 this->set_ext_suspended();
2299
2300 // _ext_suspended flag is cleared by java_resume()
2301 while (is_ext_suspended()) {
2302 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2303 }
2304 }
2305
2306 return ret;
2307 }
2308
2309 #ifdef ASSERT
2310 // verify the JavaThread has not yet been published in the Threads::list, and
2311 // hence doesn't need protection from concurrent access at this stage
2312 void JavaThread::verify_not_published() {
2313 if (!Threads_lock->owned_by_self()) {
2314 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2315 assert( !Threads::includes(this),
2316 "java thread shouldn't have been published yet!");
2317 }
2318 else {
2319 assert( !Threads::includes(this),
2320 "java thread shouldn't have been published yet!");
2321 }
2322 }
2323 #endif
2324
2325 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2326 // progress or when _suspend_flags is non-zero.
2327 // Current thread needs to self-suspend if there is a suspend request and/or
2328 // block if a safepoint is in progress.
2329 // Async exception ISN'T checked.
2330 // Note only the ThreadInVMfromNative transition can call this function
2331 // directly and when thread state is _thread_in_native_trans
2332 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2333 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2334
2335 JavaThread *curJT = JavaThread::current();
2336 bool do_self_suspend = thread->is_external_suspend();
2337
2338 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2339
2340 // If JNIEnv proxies are allowed, don't self-suspend if the target
2341 // thread is not the current thread. In older versions of jdbx, jdbx
2342 // threads could call into the VM with another thread's JNIEnv so we
2343 // can be here operating on behalf of a suspended thread (4432884).
2344 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2345 JavaThreadState state = thread->thread_state();
2346
2347 // We mark this thread_blocked state as a suspend-equivalent so
2348 // that a caller to is_ext_suspend_completed() won't be confused.
2349 // The suspend-equivalent state is cleared by java_suspend_self().
2350 thread->set_suspend_equivalent();
2351
2352 // If the safepoint code sees the _thread_in_native_trans state, it will
2353 // wait until the thread changes to other thread state. There is no
2354 // guarantee on how soon we can obtain the SR_lock and complete the
2355 // self-suspend request. It would be a bad idea to let safepoint wait for
2356 // too long. Temporarily change the state to _thread_blocked to
2357 // let the VM thread know that this thread is ready for GC. The problem
2358 // of changing thread state is that safepoint could happen just after
2359 // java_suspend_self() returns after being resumed, and VM thread will
2360 // see the _thread_blocked state. We must check for safepoint
2361 // after restoring the state and make sure we won't leave while a safepoint
2362 // is in progress.
2363 thread->set_thread_state(_thread_blocked);
2364 thread->java_suspend_self();
2365 thread->set_thread_state(state);
2366 // Make sure new state is seen by VM thread
2367 if (os::is_MP()) {
2368 if (UseMembar) {
2369 // Force a fence between the write above and read below
2370 OrderAccess::fence();
2371 } else {
2372 // Must use this rather than serialization page in particular on Windows
2373 InterfaceSupport::serialize_memory(thread);
2374 }
2375 }
2376 }
2377
2378 if (SafepointSynchronize::do_call_back()) {
2379 // If we are safepointing, then block the caller which may not be
2380 // the same as the target thread (see above).
2381 SafepointSynchronize::block(curJT);
2382 }
2383
2384 if (thread->is_deopt_suspend()) {
2385 thread->clear_deopt_suspend();
2386 RegisterMap map(thread, false);
2387 frame f = thread->last_frame();
2388 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2389 f = f.sender(&map);
2390 }
2391 if (f.id() == thread->must_deopt_id()) {
2392 thread->clear_must_deopt_id();
2393 f.deoptimize(thread);
2394 } else {
2395 fatal("missed deoptimization!");
2396 }
2397 }
2398 }
2399
2400 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2401 // progress or when _suspend_flags is non-zero.
2402 // Current thread needs to self-suspend if there is a suspend request and/or
2403 // block if a safepoint is in progress.
2404 // Also check for pending async exception (not including unsafe access error).
2405 // Note only the native==>VM/Java barriers can call this function and when
2406 // thread state is _thread_in_native_trans.
2407 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2408 check_safepoint_and_suspend_for_native_trans(thread);
2409
2410 if (thread->has_async_exception()) {
2411 // We are in _thread_in_native_trans state, don't handle unsafe
2412 // access error since that may block.
2413 thread->check_and_handle_async_exceptions(false);
2414 }
2415 }
2416
2417 // This is a variant of the normal
2418 // check_special_condition_for_native_trans with slightly different
2419 // semantics for use by critical native wrappers. It does all the
2420 // normal checks but also performs the transition back into
2421 // thread_in_Java state. This is required so that critical natives
2422 // can potentially block and perform a GC if they are the last thread
2423 // exiting the GC_locker.
2424 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2425 check_special_condition_for_native_trans(thread);
2426
2427 // Finish the transition
2428 thread->set_thread_state(_thread_in_Java);
2429
2430 if (thread->do_critical_native_unlock()) {
2431 ThreadInVMfromJavaNoAsyncException tiv(thread);
2432 GC_locker::unlock_critical(thread);
2433 thread->clear_critical_native_unlock();
2434 }
2435 }
2436
2437 // We need to guarantee the Threads_lock here, since resumes are not
2438 // allowed during safepoint synchronization
2439 // Can only resume from an external suspension
2440 void JavaThread::java_resume() {
2441 assert_locked_or_safepoint(Threads_lock);
2442
2443 // Sanity check: thread is gone, has started exiting or the thread
2444 // was not externally suspended.
2445 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2446 return;
2447 }
2448
2449 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2450
2451 clear_external_suspend();
2452
2453 if (is_ext_suspended()) {
2454 clear_ext_suspended();
2455 SR_lock()->notify_all();
2456 }
2457 }
2458
2459 void JavaThread::create_stack_guard_pages() {
2460 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2461 address low_addr = stack_base() - stack_size();
2462 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2463
2464 int allocate = os::allocate_stack_guard_pages();
2465 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2466
2467 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2468 warning("Attempt to allocate stack guard pages failed.");
2469 return;
2470 }
2471
2472 if (os::guard_memory((char *) low_addr, len)) {
2473 _stack_guard_state = stack_guard_enabled;
2474 } else {
2475 warning("Attempt to protect stack guard pages failed.");
2476 if (os::uncommit_memory((char *) low_addr, len)) {
2477 warning("Attempt to deallocate stack guard pages failed.");
2478 }
2479 }
2480 }
2481
2482 void JavaThread::remove_stack_guard_pages() {
2483 assert(Thread::current() == this, "from different thread");
2484 if (_stack_guard_state == stack_guard_unused) return;
2485 address low_addr = stack_base() - stack_size();
2486 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2487
2488 if (os::allocate_stack_guard_pages()) {
2489 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2490 _stack_guard_state = stack_guard_unused;
2491 } else {
2492 warning("Attempt to deallocate stack guard pages failed.");
2493 }
2494 } else {
2495 if (_stack_guard_state == stack_guard_unused) return;
2496 if (os::unguard_memory((char *) low_addr, len)) {
2497 _stack_guard_state = stack_guard_unused;
2498 } else {
2499 warning("Attempt to unprotect stack guard pages failed.");
2500 }
2501 }
2502 }
2503
2504 void JavaThread::enable_stack_yellow_zone() {
2505 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2506 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2507
2508 // The base notation is from the stacks point of view, growing downward.
2509 // We need to adjust it to work correctly with guard_memory()
2510 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2511
2512 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2513 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2514
2515 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2516 _stack_guard_state = stack_guard_enabled;
2517 } else {
2518 warning("Attempt to guard stack yellow zone failed.");
2519 }
2520 enable_register_stack_guard();
2521 }
2522
2523 void JavaThread::disable_stack_yellow_zone() {
2524 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2525 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2526
2527 // Simply return if called for a thread that does not use guard pages.
2528 if (_stack_guard_state == stack_guard_unused) return;
2529
2530 // The base notation is from the stacks point of view, growing downward.
2531 // We need to adjust it to work correctly with guard_memory()
2532 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2533
2534 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2535 _stack_guard_state = stack_guard_yellow_disabled;
2536 } else {
2537 warning("Attempt to unguard stack yellow zone failed.");
2538 }
2539 disable_register_stack_guard();
2540 }
2541
2542 void JavaThread::enable_stack_red_zone() {
2543 // The base notation is from the stacks point of view, growing downward.
2544 // We need to adjust it to work correctly with guard_memory()
2545 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2546 address base = stack_red_zone_base() - stack_red_zone_size();
2547
2548 guarantee(base < stack_base(),"Error calculating stack red zone");
2549 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2550
2551 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2552 warning("Attempt to guard stack red zone failed.");
2553 }
2554 }
2555
2556 void JavaThread::disable_stack_red_zone() {
2557 // The base notation is from the stacks point of view, growing downward.
2558 // We need to adjust it to work correctly with guard_memory()
2559 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2560 address base = stack_red_zone_base() - stack_red_zone_size();
2561 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2562 warning("Attempt to unguard stack red zone failed.");
2563 }
2564 }
2565
2566 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2567 // ignore is there is no stack
2568 if (!has_last_Java_frame()) return;
2569 // traverse the stack frames. Starts from top frame.
2570 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2571 frame* fr = fst.current();
2572 f(fr, fst.register_map());
2573 }
2574 }
2575
2576
2577 #ifndef PRODUCT
2578 // Deoptimization
2579 // Function for testing deoptimization
2580 void JavaThread::deoptimize() {
2581 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2582 StackFrameStream fst(this, UseBiasedLocking);
2583 bool deopt = false; // Dump stack only if a deopt actually happens.
2584 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2585 // Iterate over all frames in the thread and deoptimize
2586 for(; !fst.is_done(); fst.next()) {
2587 if(fst.current()->can_be_deoptimized()) {
2588
2589 if (only_at) {
2590 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2591 // consists of comma or carriage return separated numbers so
2592 // search for the current bci in that string.
2593 address pc = fst.current()->pc();
2594 nmethod* nm = (nmethod*) fst.current()->cb();
2595 ScopeDesc* sd = nm->scope_desc_at( pc);
2596 char buffer[8];
2597 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2598 size_t len = strlen(buffer);
2599 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2600 while (found != NULL) {
2601 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2602 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2603 // Check that the bci found is bracketed by terminators.
2604 break;
2605 }
2606 found = strstr(found + 1, buffer);
2607 }
2608 if (!found) {
2609 continue;
2610 }
2611 }
2612
2613 if (DebugDeoptimization && !deopt) {
2614 deopt = true; // One-time only print before deopt
2615 tty->print_cr("[BEFORE Deoptimization]");
2616 trace_frames();
2617 trace_stack();
2618 }
2619 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2620 }
2621 }
2622
2623 if (DebugDeoptimization && deopt) {
2624 tty->print_cr("[AFTER Deoptimization]");
2625 trace_frames();
2626 }
2627 }
2628
2629
2630 // Make zombies
2631 void JavaThread::make_zombies() {
2632 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2633 if (fst.current()->can_be_deoptimized()) {
2634 // it is a Java nmethod
2635 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2636 nm->make_not_entrant();
2637 }
2638 }
2639 }
2640 #endif // PRODUCT
2641
2642
2643 void JavaThread::deoptimized_wrt_marked_nmethods() {
2644 if (!has_last_Java_frame()) return;
2645 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2646 StackFrameStream fst(this, UseBiasedLocking);
2647 for(; !fst.is_done(); fst.next()) {
2648 if (fst.current()->should_be_deoptimized()) {
2649 if (LogCompilation && xtty != NULL) {
2650 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2651 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2652 this->name(), nm != NULL ? nm->compile_id() : -1);
2653 }
2654
2655 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2656 }
2657 }
2658 }
2659
2660
2661 // GC support
2662 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2663
2664 void JavaThread::gc_epilogue() {
2665 frames_do(frame_gc_epilogue);
2666 }
2667
2668
2669 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2670
2671 void JavaThread::gc_prologue() {
2672 frames_do(frame_gc_prologue);
2673 }
2674
2675 // If the caller is a NamedThread, then remember, in the current scope,
2676 // the given JavaThread in its _processed_thread field.
2677 class RememberProcessedThread: public StackObj {
2678 NamedThread* _cur_thr;
2679 public:
2680 RememberProcessedThread(JavaThread* jthr) {
2681 Thread* thread = Thread::current();
2682 if (thread->is_Named_thread()) {
2683 _cur_thr = (NamedThread *)thread;
2684 _cur_thr->set_processed_thread(jthr);
2685 } else {
2686 _cur_thr = NULL;
2687 }
2688 }
2689
2690 ~RememberProcessedThread() {
2691 if (_cur_thr) {
2692 _cur_thr->set_processed_thread(NULL);
2693 }
2694 }
2695 };
2696
2697 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2698 // Verify that the deferred card marks have been flushed.
2699 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2700
2701 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2702 // since there may be more than one thread using each ThreadProfiler.
2703
2704 // Traverse the GCHandles
2705 Thread::oops_do(f, cf);
2706
2707 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2708 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2709
2710 if (has_last_Java_frame()) {
2711 // Record JavaThread to GC thread
2712 RememberProcessedThread rpt(this);
2713
2714 // Traverse the privileged stack
2715 if (_privileged_stack_top != NULL) {
2716 _privileged_stack_top->oops_do(f);
2717 }
2718
2719 // traverse the registered growable array
2720 if (_array_for_gc != NULL) {
2721 for (int index = 0; index < _array_for_gc->length(); index++) {
2722 f->do_oop(_array_for_gc->adr_at(index));
2723 }
2724 }
2725
2726 // Traverse the monitor chunks
2727 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2728 chunk->oops_do(f);
2729 }
2730
2731 // Traverse the execution stack
2732 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2733 fst.current()->oops_do(f, cf, fst.register_map());
2734 }
2735 }
2736
2737 // callee_target is never live across a gc point so NULL it here should
2738 // it still contain a methdOop.
2739
2740 set_callee_target(NULL);
2741
2742 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2743 // If we have deferred set_locals there might be oops waiting to be
2744 // written
2745 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2746 if (list != NULL) {
2747 for (int i = 0; i < list->length(); i++) {
2748 list->at(i)->oops_do(f);
2749 }
2750 }
2751
2752 // Traverse instance variables at the end since the GC may be moving things
2753 // around using this function
2754 f->do_oop((oop*) &_threadObj);
2755 f->do_oop((oop*) &_vm_result);
2756 f->do_oop((oop*) &_vm_result_2);
2757 f->do_oop((oop*) &_exception_oop);
2758 f->do_oop((oop*) &_pending_async_exception);
2759
2760 if (jvmti_thread_state() != NULL) {
2761 jvmti_thread_state()->oops_do(f);
2762 }
2763 }
2764
2765 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2766 Thread::nmethods_do(cf); // (super method is a no-op)
2767
2768 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2769 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2770
2771 if (has_last_Java_frame()) {
2772 // Traverse the execution stack
2773 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2774 fst.current()->nmethods_do(cf);
2775 }
2776 }
2777 }
2778
2779 // Printing
2780 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2781 switch (_thread_state) {
2782 case _thread_uninitialized: return "_thread_uninitialized";
2783 case _thread_new: return "_thread_new";
2784 case _thread_new_trans: return "_thread_new_trans";
2785 case _thread_in_native: return "_thread_in_native";
2786 case _thread_in_native_trans: return "_thread_in_native_trans";
2787 case _thread_in_vm: return "_thread_in_vm";
2788 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2789 case _thread_in_Java: return "_thread_in_Java";
2790 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2791 case _thread_blocked: return "_thread_blocked";
2792 case _thread_blocked_trans: return "_thread_blocked_trans";
2793 default: return "unknown thread state";
2794 }
2795 }
2796
2797 #ifndef PRODUCT
2798 void JavaThread::print_thread_state_on(outputStream *st) const {
2799 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2800 };
2801 void JavaThread::print_thread_state() const {
2802 print_thread_state_on(tty);
2803 };
2804 #endif // PRODUCT
2805
2806 // Called by Threads::print() for VM_PrintThreads operation
2807 void JavaThread::print_on(outputStream *st) const {
2808 st->print("\"%s\" ", get_thread_name());
2809 oop thread_oop = threadObj();
2810 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2811 Thread::print_on(st);
2812 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2813 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2814 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2815 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2816 }
2817 #ifndef PRODUCT
2818 print_thread_state_on(st);
2819 _safepoint_state->print_on(st);
2820 #endif // PRODUCT
2821 }
2822
2823 // Called by fatal error handler. The difference between this and
2824 // JavaThread::print() is that we can't grab lock or allocate memory.
2825 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2826 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2827 oop thread_obj = threadObj();
2828 if (thread_obj != NULL) {
2829 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2830 }
2831 st->print(" [");
2832 st->print("%s", _get_thread_state_name(_thread_state));
2833 if (osthread()) {
2834 st->print(", id=%d", osthread()->thread_id());
2835 }
2836 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2837 _stack_base - _stack_size, _stack_base);
2838 st->print("]");
2839 return;
2840 }
2841
2842 // Verification
2843
2844 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2845
2846 void JavaThread::verify() {
2847 // Verify oops in the thread.
2848 oops_do(&VerifyOopClosure::verify_oop, NULL);
2849
2850 // Verify the stack frames.
2851 frames_do(frame_verify);
2852 }
2853
2854 // CR 6300358 (sub-CR 2137150)
2855 // Most callers of this method assume that it can't return NULL but a
2856 // thread may not have a name whilst it is in the process of attaching to
2857 // the VM - see CR 6412693, and there are places where a JavaThread can be
2858 // seen prior to having it's threadObj set (eg JNI attaching threads and
2859 // if vm exit occurs during initialization). These cases can all be accounted
2860 // for such that this method never returns NULL.
2861 const char* JavaThread::get_thread_name() const {
2862 #ifdef ASSERT
2863 // early safepoints can hit while current thread does not yet have TLS
2864 if (!SafepointSynchronize::is_at_safepoint()) {
2865 Thread *cur = Thread::current();
2866 if (!(cur->is_Java_thread() && cur == this)) {
2867 // Current JavaThreads are allowed to get their own name without
2868 // the Threads_lock.
2869 assert_locked_or_safepoint(Threads_lock);
2870 }
2871 }
2872 #endif // ASSERT
2873 return get_thread_name_string();
2874 }
2875
2876 // Returns a non-NULL representation of this thread's name, or a suitable
2877 // descriptive string if there is no set name
2878 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2879 const char* name_str;
2880 oop thread_obj = threadObj();
2881 if (thread_obj != NULL) {
2882 typeArrayOop name = java_lang_Thread::name(thread_obj);
2883 if (name != NULL) {
2884 if (buf == NULL) {
2885 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2886 }
2887 else {
2888 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2889 }
2890 }
2891 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2892 name_str = "<no-name - thread is attaching>";
2893 }
2894 else {
2895 name_str = Thread::name();
2896 }
2897 }
2898 else {
2899 name_str = Thread::name();
2900 }
2901 assert(name_str != NULL, "unexpected NULL thread name");
2902 return name_str;
2903 }
2904
2905
2906 const char* JavaThread::get_threadgroup_name() const {
2907 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2908 oop thread_obj = threadObj();
2909 if (thread_obj != NULL) {
2910 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2911 if (thread_group != NULL) {
2912 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2913 // ThreadGroup.name can be null
2914 if (name != NULL) {
2915 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2916 return str;
2917 }
2918 }
2919 }
2920 return NULL;
2921 }
2922
2923 const char* JavaThread::get_parent_name() const {
2924 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2925 oop thread_obj = threadObj();
2926 if (thread_obj != NULL) {
2927 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2928 if (thread_group != NULL) {
2929 oop parent = java_lang_ThreadGroup::parent(thread_group);
2930 if (parent != NULL) {
2931 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2932 // ThreadGroup.name can be null
2933 if (name != NULL) {
2934 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2935 return str;
2936 }
2937 }
2938 }
2939 }
2940 return NULL;
2941 }
2942
2943 ThreadPriority JavaThread::java_priority() const {
2944 oop thr_oop = threadObj();
2945 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2946 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2947 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2948 return priority;
2949 }
2950
2951 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2952
2953 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2954 // Link Java Thread object <-> C++ Thread
2955
2956 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2957 // and put it into a new Handle. The Handle "thread_oop" can then
2958 // be used to pass the C++ thread object to other methods.
2959
2960 // Set the Java level thread object (jthread) field of the
2961 // new thread (a JavaThread *) to C++ thread object using the
2962 // "thread_oop" handle.
2963
2964 // Set the thread field (a JavaThread *) of the
2965 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2966
2967 Handle thread_oop(Thread::current(),
2968 JNIHandles::resolve_non_null(jni_thread));
2969 assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
2970 "must be initialized");
2971 set_threadObj(thread_oop());
2972 java_lang_Thread::set_thread(thread_oop(), this);
2973
2974 if (prio == NoPriority) {
2975 prio = java_lang_Thread::priority(thread_oop());
2976 assert(prio != NoPriority, "A valid priority should be present");
2977 }
2978
2979 // Push the Java priority down to the native thread; needs Threads_lock
2980 Thread::set_priority(this, prio);
2981
2982 // Add the new thread to the Threads list and set it in motion.
2983 // We must have threads lock in order to call Threads::add.
2984 // It is crucial that we do not block before the thread is
2985 // added to the Threads list for if a GC happens, then the java_thread oop
2986 // will not be visited by GC.
2987 Threads::add(this);
2988 }
2989
2990 oop JavaThread::current_park_blocker() {
2991 // Support for JSR-166 locks
2992 oop thread_oop = threadObj();
2993 if (thread_oop != NULL &&
2994 JDK_Version::current().supports_thread_park_blocker()) {
2995 return java_lang_Thread::park_blocker(thread_oop);
2996 }
2997 return NULL;
2998 }
2999
3000
3001 void JavaThread::print_stack_on(outputStream* st) {
3002 if (!has_last_Java_frame()) return;
3003 ResourceMark rm;
3004 HandleMark hm;
3005
3006 RegisterMap reg_map(this);
3007 vframe* start_vf = last_java_vframe(®_map);
3008 int count = 0;
3009 for (vframe* f = start_vf; f; f = f->sender() ) {
3010 if (f->is_java_frame()) {
3011 javaVFrame* jvf = javaVFrame::cast(f);
3012 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3013
3014 // Print out lock information
3015 if (JavaMonitorsInStackTrace) {
3016 jvf->print_lock_info_on(st, count);
3017 }
3018 } else {
3019 // Ignore non-Java frames
3020 }
3021
3022 // Bail-out case for too deep stacks
3023 count++;
3024 if (MaxJavaStackTraceDepth == count) return;
3025 }
3026 }
3027
3028
3029 // JVMTI PopFrame support
3030 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3031 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3032 if (in_bytes(size_in_bytes) != 0) {
3033 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3034 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3035 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3036 }
3037 }
3038
3039 void* JavaThread::popframe_preserved_args() {
3040 return _popframe_preserved_args;
3041 }
3042
3043 ByteSize JavaThread::popframe_preserved_args_size() {
3044 return in_ByteSize(_popframe_preserved_args_size);
3045 }
3046
3047 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3048 int sz = in_bytes(popframe_preserved_args_size());
3049 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3050 return in_WordSize(sz / wordSize);
3051 }
3052
3053 void JavaThread::popframe_free_preserved_args() {
3054 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3055 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3056 _popframe_preserved_args = NULL;
3057 _popframe_preserved_args_size = 0;
3058 }
3059
3060 #ifndef PRODUCT
3061
3062 void JavaThread::trace_frames() {
3063 tty->print_cr("[Describe stack]");
3064 int frame_no = 1;
3065 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3066 tty->print(" %d. ", frame_no++);
3067 fst.current()->print_value_on(tty,this);
3068 tty->cr();
3069 }
3070 }
3071
3072 class PrintAndVerifyOopClosure: public OopClosure {
3073 protected:
3074 template <class T> inline void do_oop_work(T* p) {
3075 oop obj = oopDesc::load_decode_heap_oop(p);
3076 if (obj == NULL) return;
3077 tty->print(INTPTR_FORMAT ": ", p);
3078 if (obj->is_oop_or_null()) {
3079 if (obj->is_objArray()) {
3080 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3081 } else {
3082 obj->print();
3083 }
3084 } else {
3085 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3086 }
3087 tty->cr();
3088 }
3089 public:
3090 virtual void do_oop(oop* p) { do_oop_work(p); }
3091 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3092 };
3093
3094
3095 static void oops_print(frame* f, const RegisterMap *map) {
3096 PrintAndVerifyOopClosure print;
3097 f->print_value();
3098 f->oops_do(&print, NULL, (RegisterMap*)map);
3099 }
3100
3101 // Print our all the locations that contain oops and whether they are
3102 // valid or not. This useful when trying to find the oldest frame
3103 // where an oop has gone bad since the frame walk is from youngest to
3104 // oldest.
3105 void JavaThread::trace_oops() {
3106 tty->print_cr("[Trace oops]");
3107 frames_do(oops_print);
3108 }
3109
3110
3111 #ifdef ASSERT
3112 // Print or validate the layout of stack frames
3113 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3114 ResourceMark rm;
3115 PRESERVE_EXCEPTION_MARK;
3116 FrameValues values;
3117 int frame_no = 0;
3118 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3119 fst.current()->describe(values, ++frame_no);
3120 if (depth == frame_no) break;
3121 }
3122 if (validate_only) {
3123 values.validate();
3124 } else {
3125 tty->print_cr("[Describe stack layout]");
3126 values.print(this);
3127 }
3128 }
3129 #endif
3130
3131 void JavaThread::trace_stack_from(vframe* start_vf) {
3132 ResourceMark rm;
3133 int vframe_no = 1;
3134 for (vframe* f = start_vf; f; f = f->sender() ) {
3135 if (f->is_java_frame()) {
3136 javaVFrame::cast(f)->print_activation(vframe_no++);
3137 } else {
3138 f->print();
3139 }
3140 if (vframe_no > StackPrintLimit) {
3141 tty->print_cr("...<more frames>...");
3142 return;
3143 }
3144 }
3145 }
3146
3147
3148 void JavaThread::trace_stack() {
3149 if (!has_last_Java_frame()) return;
3150 ResourceMark rm;
3151 HandleMark hm;
3152 RegisterMap reg_map(this);
3153 trace_stack_from(last_java_vframe(®_map));
3154 }
3155
3156
3157 #endif // PRODUCT
3158
3159
3160 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3161 assert(reg_map != NULL, "a map must be given");
3162 frame f = last_frame();
3163 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3164 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3165 }
3166 return NULL;
3167 }
3168
3169
3170 klassOop JavaThread::security_get_caller_class(int depth) {
3171 vframeStream vfst(this);
3172 vfst.security_get_caller_frame(depth);
3173 if (!vfst.at_end()) {
3174 return vfst.method()->method_holder();
3175 }
3176 return NULL;
3177 }
3178
3179 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3180 assert(thread->is_Compiler_thread(), "must be compiler thread");
3181 CompileBroker::compiler_thread_loop();
3182 }
3183
3184 // Create a CompilerThread
3185 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3186 : JavaThread(&compiler_thread_entry) {
3187 _env = NULL;
3188 _log = NULL;
3189 _task = NULL;
3190 _queue = queue;
3191 _counters = counters;
3192 _buffer_blob = NULL;
3193 _scanned_nmethod = NULL;
3194
3195 #ifndef PRODUCT
3196 _ideal_graph_printer = NULL;
3197 #endif
3198 }
3199
3200 void CompilerThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3201 JavaThread::oops_do(f, cf);
3202 if (_scanned_nmethod != NULL && cf != NULL) {
3203 // Safepoints can occur when the sweeper is scanning an nmethod so
3204 // process it here to make sure it isn't unloaded in the middle of
3205 // a scan.
3206 cf->do_code_blob(_scanned_nmethod);
3207 }
3208 }
3209
3210 // ======= Threads ========
3211
3212 // The Threads class links together all active threads, and provides
3213 // operations over all threads. It is protected by its own Mutex
3214 // lock, which is also used in other contexts to protect thread
3215 // operations from having the thread being operated on from exiting
3216 // and going away unexpectedly (e.g., safepoint synchronization)
3217
3218 JavaThread* Threads::_thread_list = NULL;
3219 int Threads::_number_of_threads = 0;
3220 int Threads::_number_of_non_daemon_threads = 0;
3221 int Threads::_return_code = 0;
3222 size_t JavaThread::_stack_size_at_create = 0;
3223
3224 // All JavaThreads
3225 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3226
3227 void os_stream();
3228
3229 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3230 void Threads::threads_do(ThreadClosure* tc) {
3231 assert_locked_or_safepoint(Threads_lock);
3232 // ALL_JAVA_THREADS iterates through all JavaThreads
3233 ALL_JAVA_THREADS(p) {
3234 tc->do_thread(p);
3235 }
3236 // Someday we could have a table or list of all non-JavaThreads.
3237 // For now, just manually iterate through them.
3238 tc->do_thread(VMThread::vm_thread());
3239 Universe::heap()->gc_threads_do(tc);
3240 WatcherThread *wt = WatcherThread::watcher_thread();
3241 // Strictly speaking, the following NULL check isn't sufficient to make sure
3242 // the data for WatcherThread is still valid upon being examined. However,
3243 // considering that WatchThread terminates when the VM is on the way to
3244 // exit at safepoint, the chance of the above is extremely small. The right
3245 // way to prevent termination of WatcherThread would be to acquire
3246 // Terminator_lock, but we can't do that without violating the lock rank
3247 // checking in some cases.
3248 if (wt != NULL)
3249 tc->do_thread(wt);
3250
3251 // If CompilerThreads ever become non-JavaThreads, add them here
3252 }
3253
3254 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3255
3256 extern void JDK_Version_init();
3257
3258 // Check version
3259 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3260
3261 // Initialize the output stream module
3262 ostream_init();
3263
3264 // Process java launcher properties.
3265 Arguments::process_sun_java_launcher_properties(args);
3266
3267 // Initialize the os module before using TLS
3268 os::init();
3269
3270 // Initialize system properties.
3271 Arguments::init_system_properties();
3272
3273 // So that JDK version can be used as a discrimintor when parsing arguments
3274 JDK_Version_init();
3275
3276 // Update/Initialize System properties after JDK version number is known
3277 Arguments::init_version_specific_system_properties();
3278
3279 // Parse arguments
3280 jint parse_result = Arguments::parse(args);
3281 if (parse_result != JNI_OK) return parse_result;
3282
3283 if (PauseAtStartup) {
3284 os::pause();
3285 }
3286
3287 #ifndef USDT2
3288 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3289 #else /* USDT2 */
3290 HOTSPOT_VM_INIT_BEGIN();
3291 #endif /* USDT2 */
3292
3293 // Record VM creation timing statistics
3294 TraceVmCreationTime create_vm_timer;
3295 create_vm_timer.start();
3296
3297 // Timing (must come after argument parsing)
3298 TraceTime timer("Create VM", TraceStartupTime);
3299
3300 // Initialize the os module after parsing the args
3301 jint os_init_2_result = os::init_2();
3302 if (os_init_2_result != JNI_OK) return os_init_2_result;
3303
3304 // intialize TLS
3305 ThreadLocalStorage::init();
3306
3307 // Bootstrap native memory tracking, so it can start recording memory
3308 // activities before worker thread is started. This is the first phase
3309 // of bootstrapping, VM is currently running in single-thread mode.
3310 MemTracker::bootstrap_single_thread();
3311
3312 // Initialize output stream logging
3313 ostream_init_log();
3314
3315 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3316 // Must be before create_vm_init_agents()
3317 if (Arguments::init_libraries_at_startup()) {
3318 convert_vm_init_libraries_to_agents();
3319 }
3320
3321 // Launch -agentlib/-agentpath and converted -Xrun agents
3322 if (Arguments::init_agents_at_startup()) {
3323 create_vm_init_agents();
3324 }
3325
3326 // Initialize Threads state
3327 _thread_list = NULL;
3328 _number_of_threads = 0;
3329 _number_of_non_daemon_threads = 0;
3330
3331 // Initialize global data structures and create system classes in heap
3332 vm_init_globals();
3333
3334 // Attach the main thread to this os thread
3335 JavaThread* main_thread = new JavaThread();
3336 main_thread->set_thread_state(_thread_in_vm);
3337 // must do this before set_active_handles and initialize_thread_local_storage
3338 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3339 // change the stack size recorded here to one based on the java thread
3340 // stacksize. This adjusted size is what is used to figure the placement
3341 // of the guard pages.
3342 main_thread->record_stack_base_and_size();
3343 main_thread->initialize_thread_local_storage();
3344
3345 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3346
3347 if (!main_thread->set_as_starting_thread()) {
3348 vm_shutdown_during_initialization(
3349 "Failed necessary internal allocation. Out of swap space");
3350 delete main_thread;
3351 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3352 return JNI_ENOMEM;
3353 }
3354
3355 // Enable guard page *after* os::create_main_thread(), otherwise it would
3356 // crash Linux VM, see notes in os_linux.cpp.
3357 main_thread->create_stack_guard_pages();
3358
3359 // Initialize Java-Level synchronization subsystem
3360 ObjectMonitor::Initialize() ;
3361
3362 // Second phase of bootstrapping, VM is about entering multi-thread mode
3363 MemTracker::bootstrap_multi_thread();
3364
3365 // Initialize global modules
3366 jint status = init_globals();
3367 if (status != JNI_OK) {
3368 delete main_thread;
3369 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3370 return status;
3371 }
3372
3373 // Should be done after the heap is fully created
3374 main_thread->cache_global_variables();
3375
3376 HandleMark hm;
3377
3378 { MutexLocker mu(Threads_lock);
3379 Threads::add(main_thread);
3380 }
3381
3382 // Any JVMTI raw monitors entered in onload will transition into
3383 // real raw monitor. VM is setup enough here for raw monitor enter.
3384 JvmtiExport::transition_pending_onload_raw_monitors();
3385
3386 if (VerifyBeforeGC &&
3387 Universe::heap()->total_collections() >= VerifyGCStartAt) {
3388 Universe::heap()->prepare_for_verify();
3389 Universe::verify(); // make sure we're starting with a clean slate
3390 }
3391
3392 // Fully start NMT
3393 MemTracker::start();
3394
3395 // Create the VMThread
3396 { TraceTime timer("Start VMThread", TraceStartupTime);
3397 VMThread::create();
3398 Thread* vmthread = VMThread::vm_thread();
3399
3400 if (!os::create_thread(vmthread, os::vm_thread))
3401 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3402
3403 // Wait for the VM thread to become ready, and VMThread::run to initialize
3404 // Monitors can have spurious returns, must always check another state flag
3405 {
3406 MutexLocker ml(Notify_lock);
3407 os::start_thread(vmthread);
3408 while (vmthread->active_handles() == NULL) {
3409 Notify_lock->wait();
3410 }
3411 }
3412 }
3413
3414 assert (Universe::is_fully_initialized(), "not initialized");
3415 EXCEPTION_MARK;
3416
3417 // At this point, the Universe is initialized, but we have not executed
3418 // any byte code. Now is a good time (the only time) to dump out the
3419 // internal state of the JVM for sharing.
3420
3421 if (DumpSharedSpaces) {
3422 Universe::heap()->preload_and_dump(CHECK_0);
3423 ShouldNotReachHere();
3424 }
3425
3426 // Always call even when there are not JVMTI environments yet, since environments
3427 // may be attached late and JVMTI must track phases of VM execution
3428 JvmtiExport::enter_start_phase();
3429
3430 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3431 JvmtiExport::post_vm_start();
3432
3433 {
3434 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3435
3436 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3437 create_vm_init_libraries();
3438 }
3439
3440 if (InitializeJavaLangString) {
3441 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3442 } else {
3443 warning("java.lang.String not initialized");
3444 }
3445
3446 if (AggressiveOpts) {
3447 {
3448 // Forcibly initialize java/util/HashMap and mutate the private
3449 // static final "frontCacheEnabled" field before we start creating instances
3450 #ifdef ASSERT
3451 klassOop tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3452 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
3453 #endif
3454 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3455 KlassHandle k = KlassHandle(THREAD, k_o);
3456 guarantee(k.not_null(), "Must find java/util/HashMap");
3457 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3458 ik->initialize(CHECK_0);
3459 fieldDescriptor fd;
3460 // Possible we might not find this field; if so, don't break
3461 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3462 k()->java_mirror()->bool_field_put(fd.offset(), true);
3463 }
3464 }
3465
3466 if (UseStringCache) {
3467 // Forcibly initialize java/lang/StringValue and mutate the private
3468 // static final "stringCacheEnabled" field before we start creating instances
3469 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3470 // Possible that StringValue isn't present: if so, silently don't break
3471 if (k_o != NULL) {
3472 KlassHandle k = KlassHandle(THREAD, k_o);
3473 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3474 ik->initialize(CHECK_0);
3475 fieldDescriptor fd;
3476 // Possible we might not find this field: if so, silently don't break
3477 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3478 k()->java_mirror()->bool_field_put(fd.offset(), true);
3479 }
3480 }
3481 }
3482 }
3483
3484 // Initialize java_lang.System (needed before creating the thread)
3485 if (InitializeJavaLangSystem) {
3486 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3487 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3488 Handle thread_group = create_initial_thread_group(CHECK_0);
3489 Universe::set_main_thread_group(thread_group());
3490 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3491 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3492 main_thread->set_threadObj(thread_object);
3493 // Set thread status to running since main thread has
3494 // been started and running.
3495 java_lang_Thread::set_thread_status(thread_object,
3496 java_lang_Thread::RUNNABLE);
3497
3498 // The VM preresolve methods to these classes. Make sure that get initialized
3499 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3500 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3501 // The VM creates & returns objects of this class. Make sure it's initialized.
3502 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3503 call_initializeSystemClass(CHECK_0);
3504
3505 // get the Java runtime name after java.lang.System is initialized
3506 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3507 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3508 } else {
3509 warning("java.lang.System not initialized");
3510 }
3511
3512 // an instance of OutOfMemory exception has been allocated earlier
3513 if (InitializeJavaLangExceptionsErrors) {
3514 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3515 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3516 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3517 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3518 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3519 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3520 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3521 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3522 } else {
3523 warning("java.lang.OutOfMemoryError has not been initialized");
3524 warning("java.lang.NullPointerException has not been initialized");
3525 warning("java.lang.ClassCastException has not been initialized");
3526 warning("java.lang.ArrayStoreException has not been initialized");
3527 warning("java.lang.ArithmeticException has not been initialized");
3528 warning("java.lang.StackOverflowError has not been initialized");
3529 warning("java.lang.IllegalArgumentException has not been initialized");
3530 }
3531 }
3532
3533 // See : bugid 4211085.
3534 // Background : the static initializer of java.lang.Compiler tries to read
3535 // property"java.compiler" and read & write property "java.vm.info".
3536 // When a security manager is installed through the command line
3537 // option "-Djava.security.manager", the above properties are not
3538 // readable and the static initializer for java.lang.Compiler fails
3539 // resulting in a NoClassDefFoundError. This can happen in any
3540 // user code which calls methods in java.lang.Compiler.
3541 // Hack : the hack is to pre-load and initialize this class, so that only
3542 // system domains are on the stack when the properties are read.
3543 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3544 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3545 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3546 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3547 // Once that is done, we should remove this hack.
3548 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3549
3550 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3551 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3552 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3553 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3554 // This should also be taken out as soon as 4211383 gets fixed.
3555 reset_vm_info_property(CHECK_0);
3556
3557 quicken_jni_functions();
3558
3559 // Must be run after init_ft which initializes ft_enabled
3560 if (TRACE_INITIALIZE() != JNI_OK) {
3561 vm_exit_during_initialization("Failed to initialize tracing backend");
3562 }
3563
3564 // Set flag that basic initialization has completed. Used by exceptions and various
3565 // debug stuff, that does not work until all basic classes have been initialized.
3566 set_init_completed();
3567
3568 #ifndef USDT2
3569 HS_DTRACE_PROBE(hotspot, vm__init__end);
3570 #else /* USDT2 */
3571 HOTSPOT_VM_INIT_END();
3572 #endif /* USDT2 */
3573
3574 // record VM initialization completion time
3575 Management::record_vm_init_completed();
3576
3577 // Compute system loader. Note that this has to occur after set_init_completed, since
3578 // valid exceptions may be thrown in the process.
3579 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3580 // set_init_completed has just been called, causing exceptions not to be shortcut
3581 // anymore. We call vm_exit_during_initialization directly instead.
3582 SystemDictionary::compute_java_system_loader(THREAD);
3583 if (HAS_PENDING_EXCEPTION) {
3584 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3585 }
3586
3587 #ifndef SERIALGC
3588 // Support for ConcurrentMarkSweep. This should be cleaned up
3589 // and better encapsulated. The ugly nested if test would go away
3590 // once things are properly refactored. XXX YSR
3591 if (UseConcMarkSweepGC || UseG1GC) {
3592 if (UseConcMarkSweepGC) {
3593 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3594 } else {
3595 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3596 }
3597 if (HAS_PENDING_EXCEPTION) {
3598 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3599 }
3600 }
3601 #endif // SERIALGC
3602
3603 // Always call even when there are not JVMTI environments yet, since environments
3604 // may be attached late and JVMTI must track phases of VM execution
3605 JvmtiExport::enter_live_phase();
3606
3607 // Signal Dispatcher needs to be started before VMInit event is posted
3608 os::signal_init();
3609
3610 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3611 if (!DisableAttachMechanism) {
3612 if (StartAttachListener || AttachListener::init_at_startup()) {
3613 AttachListener::init();
3614 }
3615 }
3616
3617 // Launch -Xrun agents
3618 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3619 // back-end can launch with -Xdebug -Xrunjdwp.
3620 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3621 create_vm_init_libraries();
3622 }
3623
3624 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3625 JvmtiExport::post_vm_initialized();
3626
3627 if (TRACE_START() != JNI_OK) {
3628 vm_exit_during_initialization("Failed to start tracing backend.");
3629 }
3630
3631 if (CleanChunkPoolAsync) {
3632 Chunk::start_chunk_pool_cleaner_task();
3633 }
3634
3635 // initialize compiler(s)
3636 CompileBroker::compilation_init();
3637
3638 Management::initialize(THREAD);
3639 if (HAS_PENDING_EXCEPTION) {
3640 // management agent fails to start possibly due to
3641 // configuration problem and is responsible for printing
3642 // stack trace if appropriate. Simply exit VM.
3643 vm_exit(1);
3644 }
3645
3646 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3647 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3648 if (MemProfiling) MemProfiler::engage();
3649 StatSampler::engage();
3650 if (CheckJNICalls) JniPeriodicChecker::engage();
3651
3652 BiasedLocking::init();
3653
3654 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3655 call_postVMInitHook(THREAD);
3656 // The Java side of PostVMInitHook.run must deal with all
3657 // exceptions and provide means of diagnosis.
3658 if (HAS_PENDING_EXCEPTION) {
3659 CLEAR_PENDING_EXCEPTION;
3660 }
3661 }
3662
3663 {
3664 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3665 // Make sure the watcher thread can be started by WatcherThread::start()
3666 // or by dynamic enrollment.
3667 WatcherThread::make_startable();
3668 // Start up the WatcherThread if there are any periodic tasks
3669 // NOTE: All PeriodicTasks should be registered by now. If they
3670 // aren't, late joiners might appear to start slowly (we might
3671 // take a while to process their first tick).
3672 if (PeriodicTask::num_tasks() > 0) {
3673 WatcherThread::start();
3674 }
3675 }
3676
3677 // Give os specific code one last chance to start
3678 os::init_3();
3679
3680 create_vm_timer.end();
3681 return JNI_OK;
3682 }
3683
3684 // type for the Agent_OnLoad and JVM_OnLoad entry points
3685 extern "C" {
3686 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3687 }
3688 // Find a command line agent library and return its entry point for
3689 // -agentlib: -agentpath: -Xrun
3690 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3691 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3692 OnLoadEntry_t on_load_entry = NULL;
3693 void *library = agent->os_lib(); // check if we have looked it up before
3694
3695 if (library == NULL) {
3696 char buffer[JVM_MAXPATHLEN];
3697 char ebuf[1024];
3698 const char *name = agent->name();
3699 const char *msg = "Could not find agent library ";
3700
3701 if (agent->is_absolute_path()) {
3702 library = os::dll_load(name, ebuf, sizeof ebuf);
3703 if (library == NULL) {
3704 const char *sub_msg = " in absolute path, with error: ";
3705 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3706 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3707 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3708 // If we can't find the agent, exit.
3709 vm_exit_during_initialization(buf, NULL);
3710 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3711 }
3712 } else {
3713 // Try to load the agent from the standard dll directory
3714 os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
3715 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3716 if (library == NULL) { // Try the local directory
3717 char ns[1] = {0};
3718 os::dll_build_name(buffer, sizeof(buffer), ns, name);
3719 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3720 if (library == NULL) {
3721 const char *sub_msg = " on the library path, with error: ";
3722 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3723 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3724 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3725 // If we can't find the agent, exit.
3726 vm_exit_during_initialization(buf, NULL);
3727 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3728 }
3729 }
3730 }
3731 agent->set_os_lib(library);
3732 }
3733
3734 // Find the OnLoad function.
3735 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3736 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index]));
3737 if (on_load_entry != NULL) break;
3738 }
3739 return on_load_entry;
3740 }
3741
3742 // Find the JVM_OnLoad entry point
3743 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3744 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3745 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3746 }
3747
3748 // Find the Agent_OnLoad entry point
3749 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3750 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3751 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3752 }
3753
3754 // For backwards compatibility with -Xrun
3755 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3756 // treated like -agentpath:
3757 // Must be called before agent libraries are created
3758 void Threads::convert_vm_init_libraries_to_agents() {
3759 AgentLibrary* agent;
3760 AgentLibrary* next;
3761
3762 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3763 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3764 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3765
3766 // If there is an JVM_OnLoad function it will get called later,
3767 // otherwise see if there is an Agent_OnLoad
3768 if (on_load_entry == NULL) {
3769 on_load_entry = lookup_agent_on_load(agent);
3770 if (on_load_entry != NULL) {
3771 // switch it to the agent list -- so that Agent_OnLoad will be called,
3772 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3773 Arguments::convert_library_to_agent(agent);
3774 } else {
3775 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3776 }
3777 }
3778 }
3779 }
3780
3781 // Create agents for -agentlib: -agentpath: and converted -Xrun
3782 // Invokes Agent_OnLoad
3783 // Called very early -- before JavaThreads exist
3784 void Threads::create_vm_init_agents() {
3785 extern struct JavaVM_ main_vm;
3786 AgentLibrary* agent;
3787
3788 JvmtiExport::enter_onload_phase();
3789 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3790 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3791
3792 if (on_load_entry != NULL) {
3793 // Invoke the Agent_OnLoad function
3794 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3795 if (err != JNI_OK) {
3796 vm_exit_during_initialization("agent library failed to init", agent->name());
3797 }
3798 } else {
3799 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3800 }
3801 }
3802 JvmtiExport::enter_primordial_phase();
3803 }
3804
3805 extern "C" {
3806 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3807 }
3808
3809 void Threads::shutdown_vm_agents() {
3810 // Send any Agent_OnUnload notifications
3811 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3812 extern struct JavaVM_ main_vm;
3813 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3814
3815 // Find the Agent_OnUnload function.
3816 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3817 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3818 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3819
3820 // Invoke the Agent_OnUnload function
3821 if (unload_entry != NULL) {
3822 JavaThread* thread = JavaThread::current();
3823 ThreadToNativeFromVM ttn(thread);
3824 HandleMark hm(thread);
3825 (*unload_entry)(&main_vm);
3826 break;
3827 }
3828 }
3829 }
3830 }
3831
3832 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3833 // Invokes JVM_OnLoad
3834 void Threads::create_vm_init_libraries() {
3835 extern struct JavaVM_ main_vm;
3836 AgentLibrary* agent;
3837
3838 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3839 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3840
3841 if (on_load_entry != NULL) {
3842 // Invoke the JVM_OnLoad function
3843 JavaThread* thread = JavaThread::current();
3844 ThreadToNativeFromVM ttn(thread);
3845 HandleMark hm(thread);
3846 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3847 if (err != JNI_OK) {
3848 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3849 }
3850 } else {
3851 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3852 }
3853 }
3854 }
3855
3856 // Last thread running calls java.lang.Shutdown.shutdown()
3857 void JavaThread::invoke_shutdown_hooks() {
3858 HandleMark hm(this);
3859
3860 // We could get here with a pending exception, if so clear it now.
3861 if (this->has_pending_exception()) {
3862 this->clear_pending_exception();
3863 }
3864
3865 EXCEPTION_MARK;
3866 klassOop k =
3867 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3868 THREAD);
3869 if (k != NULL) {
3870 // SystemDictionary::resolve_or_null will return null if there was
3871 // an exception. If we cannot load the Shutdown class, just don't
3872 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3873 // and finalizers (if runFinalizersOnExit is set) won't be run.
3874 // Note that if a shutdown hook was registered or runFinalizersOnExit
3875 // was called, the Shutdown class would have already been loaded
3876 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3877 instanceKlassHandle shutdown_klass (THREAD, k);
3878 JavaValue result(T_VOID);
3879 JavaCalls::call_static(&result,
3880 shutdown_klass,
3881 vmSymbols::shutdown_method_name(),
3882 vmSymbols::void_method_signature(),
3883 THREAD);
3884 }
3885 CLEAR_PENDING_EXCEPTION;
3886 }
3887
3888 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3889 // the program falls off the end of main(). Another VM exit path is through
3890 // vm_exit() when the program calls System.exit() to return a value or when
3891 // there is a serious error in VM. The two shutdown paths are not exactly
3892 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3893 // and VM_Exit op at VM level.
3894 //
3895 // Shutdown sequence:
3896 // + Shutdown native memory tracking if it is on
3897 // + Wait until we are the last non-daemon thread to execute
3898 // <-- every thing is still working at this moment -->
3899 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3900 // shutdown hooks, run finalizers if finalization-on-exit
3901 // + Call before_exit(), prepare for VM exit
3902 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3903 // currently the only user of this mechanism is File.deleteOnExit())
3904 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3905 // post thread end and vm death events to JVMTI,
3906 // stop signal thread
3907 // + Call JavaThread::exit(), it will:
3908 // > release JNI handle blocks, remove stack guard pages
3909 // > remove this thread from Threads list
3910 // <-- no more Java code from this thread after this point -->
3911 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3912 // the compiler threads at safepoint
3913 // <-- do not use anything that could get blocked by Safepoint -->
3914 // + Disable tracing at JNI/JVM barriers
3915 // + Set _vm_exited flag for threads that are still running native code
3916 // + Delete this thread
3917 // + Call exit_globals()
3918 // > deletes tty
3919 // > deletes PerfMemory resources
3920 // + Return to caller
3921
3922 bool Threads::destroy_vm() {
3923 JavaThread* thread = JavaThread::current();
3924
3925 // Wait until we are the last non-daemon thread to execute
3926 { MutexLocker nu(Threads_lock);
3927 while (Threads::number_of_non_daemon_threads() > 1 )
3928 // This wait should make safepoint checks, wait without a timeout,
3929 // and wait as a suspend-equivalent condition.
3930 //
3931 // Note: If the FlatProfiler is running and this thread is waiting
3932 // for another non-daemon thread to finish, then the FlatProfiler
3933 // is waiting for the external suspend request on this thread to
3934 // complete. wait_for_ext_suspend_completion() will eventually
3935 // timeout, but that takes time. Making this wait a suspend-
3936 // equivalent condition solves that timeout problem.
3937 //
3938 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3939 Mutex::_as_suspend_equivalent_flag);
3940 }
3941
3942 // Hang forever on exit if we are reporting an error.
3943 if (ShowMessageBoxOnError && is_error_reported()) {
3944 os::infinite_sleep();
3945 }
3946 os::wait_for_keypress_at_exit();
3947
3948 if (JDK_Version::is_jdk12x_version()) {
3949 // We are the last thread running, so check if finalizers should be run.
3950 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3951 HandleMark rm(thread);
3952 Universe::run_finalizers_on_exit();
3953 } else {
3954 // run Java level shutdown hooks
3955 thread->invoke_shutdown_hooks();
3956 }
3957
3958 before_exit(thread);
3959
3960 thread->exit(true);
3961
3962 // Stop VM thread.
3963 {
3964 // 4945125 The vm thread comes to a safepoint during exit.
3965 // GC vm_operations can get caught at the safepoint, and the
3966 // heap is unparseable if they are caught. Grab the Heap_lock
3967 // to prevent this. The GC vm_operations will not be able to
3968 // queue until after the vm thread is dead.
3969 // After this point, we'll never emerge out of the safepoint before
3970 // the VM exits, so concurrent GC threads do not need to be explicitly
3971 // stopped; they remain inactive until the process exits.
3972 // Note: some concurrent G1 threads may be running during a safepoint,
3973 // but these will not be accessing the heap, just some G1-specific side
3974 // data structures that are not accessed by any other threads but them
3975 // after this point in a terminal safepoint.
3976
3977 MutexLocker ml(Heap_lock);
3978
3979 VMThread::wait_for_vm_thread_exit();
3980 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3981 VMThread::destroy();
3982 }
3983
3984 // clean up ideal graph printers
3985 #if defined(COMPILER2) && !defined(PRODUCT)
3986 IdealGraphPrinter::clean_up();
3987 #endif
3988
3989 // Now, all Java threads are gone except daemon threads. Daemon threads
3990 // running Java code or in VM are stopped by the Safepoint. However,
3991 // daemon threads executing native code are still running. But they
3992 // will be stopped at native=>Java/VM barriers. Note that we can't
3993 // simply kill or suspend them, as it is inherently deadlock-prone.
3994
3995 #ifndef PRODUCT
3996 // disable function tracing at JNI/JVM barriers
3997 TraceJNICalls = false;
3998 TraceJVMCalls = false;
3999 TraceRuntimeCalls = false;
4000 #endif
4001
4002 VM_Exit::set_vm_exited();
4003
4004 notify_vm_shutdown();
4005
4006 delete thread;
4007
4008 // exit_globals() will delete tty
4009 exit_globals();
4010
4011 return true;
4012 }
4013
4014
4015 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4016 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4017 return is_supported_jni_version(version);
4018 }
4019
4020
4021 jboolean Threads::is_supported_jni_version(jint version) {
4022 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4023 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4024 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4025 return JNI_FALSE;
4026 }
4027
4028
4029 void Threads::add(JavaThread* p, bool force_daemon) {
4030 // The threads lock must be owned at this point
4031 assert_locked_or_safepoint(Threads_lock);
4032
4033 // See the comment for this method in thread.hpp for its purpose and
4034 // why it is called here.
4035 p->initialize_queues();
4036 p->set_next(_thread_list);
4037 _thread_list = p;
4038 _number_of_threads++;
4039 oop threadObj = p->threadObj();
4040 bool daemon = true;
4041 // Bootstrapping problem: threadObj can be null for initial
4042 // JavaThread (or for threads attached via JNI)
4043 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4044 _number_of_non_daemon_threads++;
4045 daemon = false;
4046 }
4047
4048 p->set_safepoint_visible(true);
4049
4050 ThreadService::add_thread(p, daemon);
4051
4052 // Possible GC point.
4053 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4054 }
4055
4056 void Threads::remove(JavaThread* p) {
4057 // Extra scope needed for Thread_lock, so we can check
4058 // that we do not remove thread without safepoint code notice
4059 { MutexLocker ml(Threads_lock);
4060
4061 assert(includes(p), "p must be present");
4062
4063 JavaThread* current = _thread_list;
4064 JavaThread* prev = NULL;
4065
4066 while (current != p) {
4067 prev = current;
4068 current = current->next();
4069 }
4070
4071 if (prev) {
4072 prev->set_next(current->next());
4073 } else {
4074 _thread_list = p->next();
4075 }
4076 _number_of_threads--;
4077 oop threadObj = p->threadObj();
4078 bool daemon = true;
4079 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4080 _number_of_non_daemon_threads--;
4081 daemon = false;
4082
4083 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4084 // on destroy_vm will wake up.
4085 if (number_of_non_daemon_threads() == 1)
4086 Threads_lock->notify_all();
4087 }
4088 ThreadService::remove_thread(p, daemon);
4089
4090 // Make sure that safepoint code disregard this thread. This is needed since
4091 // the thread might mess around with locks after this point. This can cause it
4092 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4093 // of this thread since it is removed from the queue.
4094 p->set_terminated_value();
4095
4096 // Now, this thread is not visible to safepoint
4097 p->set_safepoint_visible(false);
4098 // once the thread becomes safepoint invisible, we can not use its per-thread
4099 // recorder. And Threads::do_threads() no longer walks this thread, so we have
4100 // to release its per-thread recorder here.
4101 MemTracker::thread_exiting(p);
4102 } // unlock Threads_lock
4103
4104 // Since Events::log uses a lock, we grab it outside the Threads_lock
4105 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4106 }
4107
4108 // Threads_lock must be held when this is called (or must be called during a safepoint)
4109 bool Threads::includes(JavaThread* p) {
4110 assert(Threads_lock->is_locked(), "sanity check");
4111 ALL_JAVA_THREADS(q) {
4112 if (q == p ) {
4113 return true;
4114 }
4115 }
4116 return false;
4117 }
4118
4119 // Operations on the Threads list for GC. These are not explicitly locked,
4120 // but the garbage collector must provide a safe context for them to run.
4121 // In particular, these things should never be called when the Threads_lock
4122 // is held by some other thread. (Note: the Safepoint abstraction also
4123 // uses the Threads_lock to gurantee this property. It also makes sure that
4124 // all threads gets blocked when exiting or starting).
4125
4126 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4127 ALL_JAVA_THREADS(p) {
4128 p->oops_do(f, cf);
4129 }
4130 VMThread::vm_thread()->oops_do(f, cf);
4131 }
4132
4133 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) {
4134 // Introduce a mechanism allowing parallel threads to claim threads as
4135 // root groups. Overhead should be small enough to use all the time,
4136 // even in sequential code.
4137 SharedHeap* sh = SharedHeap::heap();
4138 // Cannot yet substitute active_workers for n_par_threads
4139 // because of G1CollectedHeap::verify() use of
4140 // SharedHeap::process_strong_roots(). n_par_threads == 0 will
4141 // turn off parallelism in process_strong_roots while active_workers
4142 // is being used for parallelism elsewhere.
4143 bool is_par = sh->n_par_threads() > 0;
4144 assert(!is_par ||
4145 (SharedHeap::heap()->n_par_threads() ==
4146 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4147 int cp = SharedHeap::heap()->strong_roots_parity();
4148 ALL_JAVA_THREADS(p) {
4149 if (p->claim_oops_do(is_par, cp)) {
4150 p->oops_do(f, cf);
4151 }
4152 }
4153 VMThread* vmt = VMThread::vm_thread();
4154 if (vmt->claim_oops_do(is_par, cp)) {
4155 vmt->oops_do(f, cf);
4156 }
4157 }
4158
4159 #ifndef SERIALGC
4160 // Used by ParallelScavenge
4161 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4162 ALL_JAVA_THREADS(p) {
4163 q->enqueue(new ThreadRootsTask(p));
4164 }
4165 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4166 }
4167
4168 // Used by Parallel Old
4169 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4170 ALL_JAVA_THREADS(p) {
4171 q->enqueue(new ThreadRootsMarkingTask(p));
4172 }
4173 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4174 }
4175 #endif // SERIALGC
4176
4177 void Threads::nmethods_do(CodeBlobClosure* cf) {
4178 ALL_JAVA_THREADS(p) {
4179 p->nmethods_do(cf);
4180 }
4181 VMThread::vm_thread()->nmethods_do(cf);
4182 }
4183
4184 void Threads::gc_epilogue() {
4185 ALL_JAVA_THREADS(p) {
4186 p->gc_epilogue();
4187 }
4188 }
4189
4190 void Threads::gc_prologue() {
4191 ALL_JAVA_THREADS(p) {
4192 p->gc_prologue();
4193 }
4194 }
4195
4196 void Threads::deoptimized_wrt_marked_nmethods() {
4197 ALL_JAVA_THREADS(p) {
4198 p->deoptimized_wrt_marked_nmethods();
4199 }
4200 }
4201
4202
4203 // Get count Java threads that are waiting to enter the specified monitor.
4204 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4205 address monitor, bool doLock) {
4206 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4207 "must grab Threads_lock or be at safepoint");
4208 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4209
4210 int i = 0;
4211 {
4212 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4213 ALL_JAVA_THREADS(p) {
4214 if (p->is_Compiler_thread()) continue;
4215
4216 address pending = (address)p->current_pending_monitor();
4217 if (pending == monitor) { // found a match
4218 if (i < count) result->append(p); // save the first count matches
4219 i++;
4220 }
4221 }
4222 }
4223 return result;
4224 }
4225
4226
4227 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4228 assert(doLock ||
4229 Threads_lock->owned_by_self() ||
4230 SafepointSynchronize::is_at_safepoint(),
4231 "must grab Threads_lock or be at safepoint");
4232
4233 // NULL owner means not locked so we can skip the search
4234 if (owner == NULL) return NULL;
4235
4236 {
4237 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4238 ALL_JAVA_THREADS(p) {
4239 // first, see if owner is the address of a Java thread
4240 if (owner == (address)p) return p;
4241 }
4242 }
4243 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
4244 if (UseHeavyMonitors) return NULL;
4245
4246 //
4247 // If we didn't find a matching Java thread and we didn't force use of
4248 // heavyweight monitors, then the owner is the stack address of the
4249 // Lock Word in the owning Java thread's stack.
4250 //
4251 JavaThread* the_owner = NULL;
4252 {
4253 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4254 ALL_JAVA_THREADS(q) {
4255 if (q->is_lock_owned(owner)) {
4256 the_owner = q;
4257 break;
4258 }
4259 }
4260 }
4261 assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
4262 return the_owner;
4263 }
4264
4265 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4266 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4267 char buf[32];
4268 st->print_cr(os::local_time_string(buf, sizeof(buf)));
4269
4270 st->print_cr("Full thread dump %s (%s %s):",
4271 Abstract_VM_Version::vm_name(),
4272 Abstract_VM_Version::vm_release(),
4273 Abstract_VM_Version::vm_info_string()
4274 );
4275 st->cr();
4276
4277 #ifndef SERIALGC
4278 // Dump concurrent locks
4279 ConcurrentLocksDump concurrent_locks;
4280 if (print_concurrent_locks) {
4281 concurrent_locks.dump_at_safepoint();
4282 }
4283 #endif // SERIALGC
4284
4285 ALL_JAVA_THREADS(p) {
4286 ResourceMark rm;
4287 p->print_on(st);
4288 if (print_stacks) {
4289 if (internal_format) {
4290 p->trace_stack();
4291 } else {
4292 p->print_stack_on(st);
4293 }
4294 }
4295 st->cr();
4296 #ifndef SERIALGC
4297 if (print_concurrent_locks) {
4298 concurrent_locks.print_locks_on(p, st);
4299 }
4300 #endif // SERIALGC
4301 }
4302
4303 VMThread::vm_thread()->print_on(st);
4304 st->cr();
4305 Universe::heap()->print_gc_threads_on(st);
4306 WatcherThread* wt = WatcherThread::watcher_thread();
4307 if (wt != NULL) wt->print_on(st);
4308 st->cr();
4309 CompileBroker::print_compiler_threads_on(st);
4310 st->flush();
4311 }
4312
4313 // Threads::print_on_error() is called by fatal error handler. It's possible
4314 // that VM is not at safepoint and/or current thread is inside signal handler.
4315 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4316 // memory (even in resource area), it might deadlock the error handler.
4317 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4318 bool found_current = false;
4319 st->print_cr("Java Threads: ( => current thread )");
4320 ALL_JAVA_THREADS(thread) {
4321 bool is_current = (current == thread);
4322 found_current = found_current || is_current;
4323
4324 st->print("%s", is_current ? "=>" : " ");
4325
4326 st->print(PTR_FORMAT, thread);
4327 st->print(" ");
4328 thread->print_on_error(st, buf, buflen);
4329 st->cr();
4330 }
4331 st->cr();
4332
4333 st->print_cr("Other Threads:");
4334 if (VMThread::vm_thread()) {
4335 bool is_current = (current == VMThread::vm_thread());
4336 found_current = found_current || is_current;
4337 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4338
4339 st->print(PTR_FORMAT, VMThread::vm_thread());
4340 st->print(" ");
4341 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4342 st->cr();
4343 }
4344 WatcherThread* wt = WatcherThread::watcher_thread();
4345 if (wt != NULL) {
4346 bool is_current = (current == wt);
4347 found_current = found_current || is_current;
4348 st->print("%s", is_current ? "=>" : " ");
4349
4350 st->print(PTR_FORMAT, wt);
4351 st->print(" ");
4352 wt->print_on_error(st, buf, buflen);
4353 st->cr();
4354 }
4355 if (!found_current) {
4356 st->cr();
4357 st->print("=>" PTR_FORMAT " (exited) ", current);
4358 current->print_on_error(st, buf, buflen);
4359 st->cr();
4360 }
4361 }
4362
4363 // Internal SpinLock and Mutex
4364 // Based on ParkEvent
4365
4366 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4367 //
4368 // We employ SpinLocks _only for low-contention, fixed-length
4369 // short-duration critical sections where we're concerned
4370 // about native mutex_t or HotSpot Mutex:: latency.
4371 // The mux construct provides a spin-then-block mutual exclusion
4372 // mechanism.
4373 //
4374 // Testing has shown that contention on the ListLock guarding gFreeList
4375 // is common. If we implement ListLock as a simple SpinLock it's common
4376 // for the JVM to devolve to yielding with little progress. This is true
4377 // despite the fact that the critical sections protected by ListLock are
4378 // extremely short.
4379 //
4380 // TODO-FIXME: ListLock should be of type SpinLock.
4381 // We should make this a 1st-class type, integrated into the lock
4382 // hierarchy as leaf-locks. Critically, the SpinLock structure
4383 // should have sufficient padding to avoid false-sharing and excessive
4384 // cache-coherency traffic.
4385
4386
4387 typedef volatile int SpinLockT ;
4388
4389 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4390 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4391 return ; // normal fast-path return
4392 }
4393
4394 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4395 TEVENT (SpinAcquire - ctx) ;
4396 int ctr = 0 ;
4397 int Yields = 0 ;
4398 for (;;) {
4399 while (*adr != 0) {
4400 ++ctr ;
4401 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4402 if (Yields > 5) {
4403 // Consider using a simple NakedSleep() instead.
4404 // Then SpinAcquire could be called by non-JVM threads
4405 Thread::current()->_ParkEvent->park(1) ;
4406 } else {
4407 os::NakedYield() ;
4408 ++Yields ;
4409 }
4410 } else {
4411 SpinPause() ;
4412 }
4413 }
4414 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4415 }
4416 }
4417
4418 void Thread::SpinRelease (volatile int * adr) {
4419 assert (*adr != 0, "invariant") ;
4420 OrderAccess::fence() ; // guarantee at least release consistency.
4421 // Roach-motel semantics.
4422 // It's safe if subsequent LDs and STs float "up" into the critical section,
4423 // but prior LDs and STs within the critical section can't be allowed
4424 // to reorder or float past the ST that releases the lock.
4425 *adr = 0 ;
4426 }
4427
4428 // muxAcquire and muxRelease:
4429 //
4430 // * muxAcquire and muxRelease support a single-word lock-word construct.
4431 // The LSB of the word is set IFF the lock is held.
4432 // The remainder of the word points to the head of a singly-linked list
4433 // of threads blocked on the lock.
4434 //
4435 // * The current implementation of muxAcquire-muxRelease uses its own
4436 // dedicated Thread._MuxEvent instance. If we're interested in
4437 // minimizing the peak number of extant ParkEvent instances then
4438 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4439 // as certain invariants were satisfied. Specifically, care would need
4440 // to be taken with regards to consuming unpark() "permits".
4441 // A safe rule of thumb is that a thread would never call muxAcquire()
4442 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4443 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4444 // consume an unpark() permit intended for monitorenter, for instance.
4445 // One way around this would be to widen the restricted-range semaphore
4446 // implemented in park(). Another alternative would be to provide
4447 // multiple instances of the PlatformEvent() for each thread. One
4448 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4449 //
4450 // * Usage:
4451 // -- Only as leaf locks
4452 // -- for short-term locking only as muxAcquire does not perform
4453 // thread state transitions.
4454 //
4455 // Alternatives:
4456 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4457 // but with parking or spin-then-park instead of pure spinning.
4458 // * Use Taura-Oyama-Yonenzawa locks.
4459 // * It's possible to construct a 1-0 lock if we encode the lockword as
4460 // (List,LockByte). Acquire will CAS the full lockword while Release
4461 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4462 // acquiring threads use timers (ParkTimed) to detect and recover from
4463 // the stranding window. Thread/Node structures must be aligned on 256-byte
4464 // boundaries by using placement-new.
4465 // * Augment MCS with advisory back-link fields maintained with CAS().
4466 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4467 // The validity of the backlinks must be ratified before we trust the value.
4468 // If the backlinks are invalid the exiting thread must back-track through the
4469 // the forward links, which are always trustworthy.
4470 // * Add a successor indication. The LockWord is currently encoded as
4471 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4472 // to provide the usual futile-wakeup optimization.
4473 // See RTStt for details.
4474 // * Consider schedctl.sc_nopreempt to cover the critical section.
4475 //
4476
4477
4478 typedef volatile intptr_t MutexT ; // Mux Lock-word
4479 enum MuxBits { LOCKBIT = 1 } ;
4480
4481 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4482 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4483 if (w == 0) return ;
4484 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4485 return ;
4486 }
4487
4488 TEVENT (muxAcquire - Contention) ;
4489 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4490 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4491 for (;;) {
4492 int its = (os::is_MP() ? 100 : 0) + 1 ;
4493
4494 // Optional spin phase: spin-then-park strategy
4495 while (--its >= 0) {
4496 w = *Lock ;
4497 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4498 return ;
4499 }
4500 }
4501
4502 Self->reset() ;
4503 Self->OnList = intptr_t(Lock) ;
4504 // The following fence() isn't _strictly necessary as the subsequent
4505 // CAS() both serializes execution and ratifies the fetched *Lock value.
4506 OrderAccess::fence();
4507 for (;;) {
4508 w = *Lock ;
4509 if ((w & LOCKBIT) == 0) {
4510 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4511 Self->OnList = 0 ; // hygiene - allows stronger asserts
4512 return ;
4513 }
4514 continue ; // Interference -- *Lock changed -- Just retry
4515 }
4516 assert (w & LOCKBIT, "invariant") ;
4517 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4518 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4519 }
4520
4521 while (Self->OnList != 0) {
4522 Self->park() ;
4523 }
4524 }
4525 }
4526
4527 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4528 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4529 if (w == 0) return ;
4530 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4531 return ;
4532 }
4533
4534 TEVENT (muxAcquire - Contention) ;
4535 ParkEvent * ReleaseAfter = NULL ;
4536 if (ev == NULL) {
4537 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4538 }
4539 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4540 for (;;) {
4541 guarantee (ev->OnList == 0, "invariant") ;
4542 int its = (os::is_MP() ? 100 : 0) + 1 ;
4543
4544 // Optional spin phase: spin-then-park strategy
4545 while (--its >= 0) {
4546 w = *Lock ;
4547 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4548 if (ReleaseAfter != NULL) {
4549 ParkEvent::Release (ReleaseAfter) ;
4550 }
4551 return ;
4552 }
4553 }
4554
4555 ev->reset() ;
4556 ev->OnList = intptr_t(Lock) ;
4557 // The following fence() isn't _strictly necessary as the subsequent
4558 // CAS() both serializes execution and ratifies the fetched *Lock value.
4559 OrderAccess::fence();
4560 for (;;) {
4561 w = *Lock ;
4562 if ((w & LOCKBIT) == 0) {
4563 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4564 ev->OnList = 0 ;
4565 // We call ::Release while holding the outer lock, thus
4566 // artificially lengthening the critical section.
4567 // Consider deferring the ::Release() until the subsequent unlock(),
4568 // after we've dropped the outer lock.
4569 if (ReleaseAfter != NULL) {
4570 ParkEvent::Release (ReleaseAfter) ;
4571 }
4572 return ;
4573 }
4574 continue ; // Interference -- *Lock changed -- Just retry
4575 }
4576 assert (w & LOCKBIT, "invariant") ;
4577 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4578 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4579 }
4580
4581 while (ev->OnList != 0) {
4582 ev->park() ;
4583 }
4584 }
4585 }
4586
4587 // Release() must extract a successor from the list and then wake that thread.
4588 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4589 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4590 // Release() would :
4591 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4592 // (B) Extract a successor from the private list "in-hand"
4593 // (C) attempt to CAS() the residual back into *Lock over null.
4594 // If there were any newly arrived threads and the CAS() would fail.
4595 // In that case Release() would detach the RATs, re-merge the list in-hand
4596 // with the RATs and repeat as needed. Alternately, Release() might
4597 // detach and extract a successor, but then pass the residual list to the wakee.
4598 // The wakee would be responsible for reattaching and remerging before it
4599 // competed for the lock.
4600 //
4601 // Both "pop" and DMR are immune from ABA corruption -- there can be
4602 // multiple concurrent pushers, but only one popper or detacher.
4603 // This implementation pops from the head of the list. This is unfair,
4604 // but tends to provide excellent throughput as hot threads remain hot.
4605 // (We wake recently run threads first).
4606
4607 void Thread::muxRelease (volatile intptr_t * Lock) {
4608 for (;;) {
4609 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4610 assert (w & LOCKBIT, "invariant") ;
4611 if (w == LOCKBIT) return ;
4612 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4613 assert (List != NULL, "invariant") ;
4614 assert (List->OnList == intptr_t(Lock), "invariant") ;
4615 ParkEvent * nxt = List->ListNext ;
4616
4617 // The following CAS() releases the lock and pops the head element.
4618 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4619 continue ;
4620 }
4621 List->OnList = 0 ;
4622 OrderAccess::fence() ;
4623 List->unpark () ;
4624 return ;
4625 }
4626 }
4627
4628
4629 void Threads::verify() {
4630 ALL_JAVA_THREADS(p) {
4631 p->verify();
4632 }
4633 VMThread* thread = VMThread::vm_thread();
4634 if (thread != NULL) thread->verify();
4635 }