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/metaspaceShared.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "memory/universe.inline.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/objArrayOop.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/symbol.hpp"
44 #include "prims/jvm_misc.hpp"
45 #include "prims/jvmtiExport.hpp"
46 #include "prims/jvmtiThreadState.hpp"
47 #include "prims/privilegedStack.hpp"
48 #include "runtime/aprofiler.hpp"
49 #include "runtime/arguments.hpp"
50 #include "runtime/biasedLocking.hpp"
51 #include "runtime/deoptimization.hpp"
52 #include "runtime/fprofiler.hpp"
53 #include "runtime/frame.inline.hpp"
54 #include "runtime/init.hpp"
55 #include "runtime/interfaceSupport.hpp"
56 #include "runtime/java.hpp"
57 #include "runtime/javaCalls.hpp"
58 #include "runtime/jniPeriodicChecker.hpp"
59 #include "runtime/memprofiler.hpp"
60 #include "runtime/mutexLocker.hpp"
61 #include "runtime/objectMonitor.hpp"
62 #include "runtime/osThread.hpp"
63 #include "runtime/safepoint.hpp"
64 #include "runtime/sharedRuntime.hpp"
65 #include "runtime/statSampler.hpp"
66 #include "runtime/stubRoutines.hpp"
67 #include "runtime/task.hpp"
68 #include "runtime/thread.inline.hpp"
69 #include "runtime/threadCritical.hpp"
70 #include "runtime/threadLocalStorage.hpp"
71 #include "runtime/vframe.hpp"
72 #include "runtime/vframeArray.hpp"
73 #include "runtime/vframe_hp.hpp"
74 #include "runtime/vmThread.hpp"
75 #include "runtime/vm_operations.hpp"
76 #include "services/attachListener.hpp"
77 #include "services/management.hpp"
78 #include "services/memTracker.hpp"
79 #include "services/threadService.hpp"
80 #include "trace/tracing.hpp"
81 #include "trace/traceMacros.hpp"
82 #include "utilities/defaultStream.hpp"
83 #include "utilities/dtrace.hpp"
84 #include "utilities/events.hpp"
85 #include "utilities/preserveException.hpp"
86 #include "utilities/macros.hpp"
87 #ifdef TARGET_OS_FAMILY_linux
88 # include "os_linux.inline.hpp"
89 #endif
90 #ifdef TARGET_OS_FAMILY_solaris
91 # include "os_solaris.inline.hpp"
92 #endif
93 #ifdef TARGET_OS_FAMILY_windows
94 # include "os_windows.inline.hpp"
95 #endif
96 #ifdef TARGET_OS_FAMILY_bsd
97 # include "os_bsd.inline.hpp"
98 #endif
99 #if INCLUDE_ALL_GCS
100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
102 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
103 #endif // INCLUDE_ALL_GCS
104 #ifdef COMPILER1
105 #include "c1/c1_Compiler.hpp"
106 #endif
107 #ifdef COMPILER2
108 #include "opto/c2compiler.hpp"
109 #include "opto/idealGraphPrinter.hpp"
110 #endif
111
112 #ifdef DTRACE_ENABLED
113
114 // Only bother with this argument setup if dtrace is available
115
116 #ifndef USDT2
117 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
118 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
119 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
120 intptr_t, intptr_t, bool);
121 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
122 intptr_t, intptr_t, bool);
123
124 #define DTRACE_THREAD_PROBE(probe, javathread) \
125 { \
126 ResourceMark rm(this); \
127 int len = 0; \
128 const char* name = (javathread)->get_thread_name(); \
129 len = strlen(name); \
130 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
131 name, len, \
132 java_lang_Thread::thread_id((javathread)->threadObj()), \
133 (javathread)->osthread()->thread_id(), \
134 java_lang_Thread::is_daemon((javathread)->threadObj())); \
135 }
136
137 #else /* USDT2 */
138
139 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
140 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
141
142 #define DTRACE_THREAD_PROBE(probe, javathread) \
143 { \
144 ResourceMark rm(this); \
145 int len = 0; \
146 const char* name = (javathread)->get_thread_name(); \
147 len = strlen(name); \
148 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
149 (char *) name, len, \
150 java_lang_Thread::thread_id((javathread)->threadObj()), \
151 (uintptr_t) (javathread)->osthread()->thread_id(), \
152 java_lang_Thread::is_daemon((javathread)->threadObj())); \
153 }
154
155 #endif /* USDT2 */
156
157 #else // ndef DTRACE_ENABLED
158
159 #define DTRACE_THREAD_PROBE(probe, javathread)
160
161 #endif // ndef DTRACE_ENABLED
162
163
164 // Class hierarchy
165 // - Thread
166 // - VMThread
167 // - WatcherThread
168 // - ConcurrentMarkSweepThread
169 // - JavaThread
170 // - CompilerThread
171
172 // ======= Thread ========
173 // Support for forcing alignment of thread objects for biased locking
174 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
175 if (UseBiasedLocking) {
176 const int alignment = markOopDesc::biased_lock_alignment;
177 size_t aligned_size = size + (alignment - sizeof(intptr_t));
178 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
179 : AllocateHeap(aligned_size, flags, CURRENT_PC,
180 AllocFailStrategy::RETURN_NULL);
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 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
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_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(300, true));
224 set_active_handles(NULL);
225 set_free_handle_block(NULL);
226 set_last_handle_mark(NULL);
227
228 // This initial value ==> never claimed.
229 _oops_do_parity = 0;
230
231 // the handle mark links itself to last_handle_mark
232 new HandleMark(this);
233
234 // plain initialization
235 debug_only(_owned_locks = NULL;)
236 debug_only(_allow_allocation_count = 0;)
237 NOT_PRODUCT(_allow_safepoint_count = 0;)
238 NOT_PRODUCT(_skip_gcalot = false;)
239 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
240 _jvmti_env_iteration_count = 0;
241 set_allocated_bytes(0);
242 _vm_operation_started_count = 0;
243 _vm_operation_completed_count = 0;
244 _current_pending_monitor = NULL;
245 _current_pending_monitor_is_from_java = true;
246 _current_waiting_monitor = NULL;
247 _num_nested_signal = 0;
248 omFreeList = NULL ;
249 omFreeCount = 0 ;
250 omFreeProvision = 32 ;
251 omInUseList = NULL ;
252 omInUseCount = 0 ;
253
254 #ifdef ASSERT
255 _visited_for_critical_count = false;
256 #endif
257
258 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
259 _suspend_flags = 0;
260
261 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
262 _hashStateX = os::random() ;
263 _hashStateY = 842502087 ;
264 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
265 _hashStateW = 273326509 ;
266
267 _OnTrap = 0 ;
268 _schedctl = NULL ;
269 _Stalled = 0 ;
270 _TypeTag = 0x2BAD ;
271
272 // Many of the following fields are effectively final - immutable
273 // Note that nascent threads can't use the Native Monitor-Mutex
274 // construct until the _MutexEvent is initialized ...
275 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
276 // we might instead use a stack of ParkEvents that we could provision on-demand.
277 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
278 // and ::Release()
279 _ParkEvent = ParkEvent::Allocate (this) ;
280 _SleepEvent = ParkEvent::Allocate (this) ;
281 _MutexEvent = ParkEvent::Allocate (this) ;
282 _MuxEvent = ParkEvent::Allocate (this) ;
283
284 #ifdef CHECK_UNHANDLED_OOPS
285 if (CheckUnhandledOops) {
286 _unhandled_oops = new UnhandledOops(this);
287 }
288 #endif // CHECK_UNHANDLED_OOPS
289 #ifdef ASSERT
290 if (UseBiasedLocking) {
291 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
292 assert(this == _real_malloc_address ||
293 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
294 "bug in forced alignment of thread objects");
295 }
296 #endif /* ASSERT */
297 }
298
299 void Thread::initialize_thread_local_storage() {
300 // Note: Make sure this method only calls
301 // non-blocking operations. Otherwise, it might not work
302 // with the thread-startup/safepoint interaction.
303
304 // During Java thread startup, safepoint code should allow this
305 // method to complete because it may need to allocate memory to
306 // store information for the new thread.
307
308 // initialize structure dependent on thread local storage
309 ThreadLocalStorage::set_thread(this);
310 }
311
312 void Thread::record_stack_base_and_size() {
313 set_stack_base(os::current_stack_base());
314 set_stack_size(os::current_stack_size());
315 if (is_Java_thread()) {
316 ((JavaThread*) this)->set_stack_overflow_limit();
317 }
318 // CR 7190089: on Solaris, primordial thread's stack is adjusted
319 // in initialize_thread(). Without the adjustment, stack size is
320 // incorrect if stack is set to unlimited (ulimit -s unlimited).
321 // So far, only Solaris has real implementation of initialize_thread().
322 //
323 // set up any platform-specific state.
324 os::initialize_thread(this);
325
326 #if INCLUDE_NMT
327 // record thread's native stack, stack grows downward
328 address stack_low_addr = stack_base() - stack_size();
329 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this,
330 CURRENT_PC);
331 #endif // INCLUDE_NMT
332 }
333
334
335 Thread::~Thread() {
336 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
337 ObjectSynchronizer::omFlush (this) ;
338
339 // stack_base can be NULL if the thread is never started or exited before
340 // record_stack_base_and_size called. Although, we would like to ensure
341 // that all started threads do call record_stack_base_and_size(), there is
342 // not proper way to enforce that.
343 #if INCLUDE_NMT
344 if (_stack_base != NULL) {
345 address low_stack_addr = stack_base() - stack_size();
346 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this);
347 #ifdef ASSERT
348 set_stack_base(NULL);
349 #endif
350 }
351 #endif // INCLUDE_NMT
352
353 // deallocate data structures
354 delete resource_area();
355 // since the handle marks are using the handle area, we have to deallocated the root
356 // handle mark before deallocating the thread's handle area,
357 assert(last_handle_mark() != NULL, "check we have an element");
358 delete last_handle_mark();
359 assert(last_handle_mark() == NULL, "check we have reached the end");
360
361 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
362 // We NULL out the fields for good hygiene.
363 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
364 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
365 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
366 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
367
368 delete handle_area();
369 delete metadata_handles();
370
371 // osthread() can be NULL, if creation of thread failed.
372 if (osthread() != NULL) os::free_thread(osthread());
373
374 delete _SR_lock;
375
376 // clear thread local storage if the Thread is deleting itself
377 if (this == Thread::current()) {
378 ThreadLocalStorage::set_thread(NULL);
379 } else {
380 // In the case where we're not the current thread, invalidate all the
381 // caches in case some code tries to get the current thread or the
382 // thread that was destroyed, and gets stale information.
383 ThreadLocalStorage::invalidate_all();
384 }
385 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
386 }
387
388 // NOTE: dummy function for assertion purpose.
389 void Thread::run() {
390 ShouldNotReachHere();
391 }
392
393 #ifdef ASSERT
394 // Private method to check for dangling thread pointer
395 void check_for_dangling_thread_pointer(Thread *thread) {
396 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
397 "possibility of dangling Thread pointer");
398 }
399 #endif
400
401
402 #ifndef PRODUCT
403 // Tracing method for basic thread operations
404 void Thread::trace(const char* msg, const Thread* const thread) {
405 if (!TraceThreadEvents) return;
406 ResourceMark rm;
407 ThreadCritical tc;
408 const char *name = "non-Java thread";
409 int prio = -1;
410 if (thread->is_Java_thread()
411 && !thread->is_Compiler_thread()) {
412 // The Threads_lock must be held to get information about
413 // this thread but may not be in some situations when
414 // tracing thread events.
415 bool release_Threads_lock = false;
416 if (!Threads_lock->owned_by_self()) {
417 Threads_lock->lock();
418 release_Threads_lock = true;
419 }
420 JavaThread* jt = (JavaThread *)thread;
421 name = (char *)jt->get_thread_name();
422 oop thread_oop = jt->threadObj();
423 if (thread_oop != NULL) {
424 prio = java_lang_Thread::priority(thread_oop);
425 }
426 if (release_Threads_lock) {
427 Threads_lock->unlock();
428 }
429 }
430 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
431 }
432 #endif
433
434
435 ThreadPriority Thread::get_priority(const Thread* const thread) {
436 trace("get priority", thread);
437 ThreadPriority priority;
438 // Can return an error!
439 (void)os::get_priority(thread, priority);
440 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
441 return priority;
442 }
443
444 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
445 trace("set priority", thread);
446 debug_only(check_for_dangling_thread_pointer(thread);)
447 // Can return an error!
448 (void)os::set_priority(thread, priority);
449 }
450
451
452 void Thread::start(Thread* thread) {
453 trace("start", thread);
454 // Start is different from resume in that its safety is guaranteed by context or
455 // being called from a Java method synchronized on the Thread object.
456 if (!DisableStartThread) {
457 if (thread->is_Java_thread()) {
458 // Initialize the thread state to RUNNABLE before starting this thread.
459 // Can not set it after the thread started because we do not know the
460 // exact thread state at that time. It could be in MONITOR_WAIT or
461 // in SLEEPING or some other state.
462 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
463 java_lang_Thread::RUNNABLE);
464 }
465 os::start_thread(thread);
466 }
467 }
468
469 // Enqueue a VM_Operation to do the job for us - sometime later
470 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
471 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
472 VMThread::execute(vm_stop);
473 }
474
475
476 //
477 // Check if an external suspend request has completed (or has been
478 // cancelled). Returns true if the thread is externally suspended and
479 // false otherwise.
480 //
481 // The bits parameter returns information about the code path through
482 // the routine. Useful for debugging:
483 //
484 // set in is_ext_suspend_completed():
485 // 0x00000001 - routine was entered
486 // 0x00000010 - routine return false at end
487 // 0x00000100 - thread exited (return false)
488 // 0x00000200 - suspend request cancelled (return false)
489 // 0x00000400 - thread suspended (return true)
490 // 0x00001000 - thread is in a suspend equivalent state (return true)
491 // 0x00002000 - thread is native and walkable (return true)
492 // 0x00004000 - thread is native_trans and walkable (needed retry)
493 //
494 // set in wait_for_ext_suspend_completion():
495 // 0x00010000 - routine was entered
496 // 0x00020000 - suspend request cancelled before loop (return false)
497 // 0x00040000 - thread suspended before loop (return true)
498 // 0x00080000 - suspend request cancelled in loop (return false)
499 // 0x00100000 - thread suspended in loop (return true)
500 // 0x00200000 - suspend not completed during retry loop (return false)
501 //
502
503 // Helper class for tracing suspend wait debug bits.
504 //
505 // 0x00000100 indicates that the target thread exited before it could
506 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
507 // 0x00080000 each indicate a cancelled suspend request so they don't
508 // count as wait failures either.
509 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
510
511 class TraceSuspendDebugBits : public StackObj {
512 private:
513 JavaThread * jt;
514 bool is_wait;
515 bool called_by_wait; // meaningful when !is_wait
516 uint32_t * bits;
517
518 public:
519 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
520 uint32_t *_bits) {
521 jt = _jt;
522 is_wait = _is_wait;
523 called_by_wait = _called_by_wait;
524 bits = _bits;
525 }
526
527 ~TraceSuspendDebugBits() {
528 if (!is_wait) {
529 #if 1
530 // By default, don't trace bits for is_ext_suspend_completed() calls.
531 // That trace is very chatty.
532 return;
533 #else
534 if (!called_by_wait) {
535 // If tracing for is_ext_suspend_completed() is enabled, then only
536 // trace calls to it from wait_for_ext_suspend_completion()
537 return;
538 }
539 #endif
540 }
541
542 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
543 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
544 MutexLocker ml(Threads_lock); // needed for get_thread_name()
545 ResourceMark rm;
546
547 tty->print_cr(
548 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
549 jt->get_thread_name(), *bits);
550
551 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
552 }
553 }
554 }
555 };
556 #undef DEBUG_FALSE_BITS
557
558
559 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
560 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
561
562 bool did_trans_retry = false; // only do thread_in_native_trans retry once
563 bool do_trans_retry; // flag to force the retry
564
565 *bits |= 0x00000001;
566
567 do {
568 do_trans_retry = false;
569
570 if (is_exiting()) {
571 // Thread is in the process of exiting. This is always checked
572 // first to reduce the risk of dereferencing a freed JavaThread.
573 *bits |= 0x00000100;
574 return false;
575 }
576
577 if (!is_external_suspend()) {
578 // Suspend request is cancelled. This is always checked before
579 // is_ext_suspended() to reduce the risk of a rogue resume
580 // confusing the thread that made the suspend request.
581 *bits |= 0x00000200;
582 return false;
583 }
584
585 if (is_ext_suspended()) {
586 // thread is suspended
587 *bits |= 0x00000400;
588 return true;
589 }
590
591 // Now that we no longer do hard suspends of threads running
592 // native code, the target thread can be changing thread state
593 // while we are in this routine:
594 //
595 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
596 //
597 // We save a copy of the thread state as observed at this moment
598 // and make our decision about suspend completeness based on the
599 // copy. This closes the race where the thread state is seen as
600 // _thread_in_native_trans in the if-thread_blocked check, but is
601 // seen as _thread_blocked in if-thread_in_native_trans check.
602 JavaThreadState save_state = thread_state();
603
604 if (save_state == _thread_blocked && is_suspend_equivalent()) {
605 // If the thread's state is _thread_blocked and this blocking
606 // condition is known to be equivalent to a suspend, then we can
607 // consider the thread to be externally suspended. This means that
608 // the code that sets _thread_blocked has been modified to do
609 // self-suspension if the blocking condition releases. We also
610 // used to check for CONDVAR_WAIT here, but that is now covered by
611 // the _thread_blocked with self-suspension check.
612 //
613 // Return true since we wouldn't be here unless there was still an
614 // external suspend request.
615 *bits |= 0x00001000;
616 return true;
617 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
618 // Threads running native code will self-suspend on native==>VM/Java
619 // transitions. If its stack is walkable (should always be the case
620 // unless this function is called before the actual java_suspend()
621 // call), then the wait is done.
622 *bits |= 0x00002000;
623 return true;
624 } else if (!called_by_wait && !did_trans_retry &&
625 save_state == _thread_in_native_trans &&
626 frame_anchor()->walkable()) {
627 // The thread is transitioning from thread_in_native to another
628 // thread state. check_safepoint_and_suspend_for_native_trans()
629 // will force the thread to self-suspend. If it hasn't gotten
630 // there yet we may have caught the thread in-between the native
631 // code check above and the self-suspend. Lucky us. If we were
632 // called by wait_for_ext_suspend_completion(), then it
633 // will be doing the retries so we don't have to.
634 //
635 // Since we use the saved thread state in the if-statement above,
636 // there is a chance that the thread has already transitioned to
637 // _thread_blocked by the time we get here. In that case, we will
638 // make a single unnecessary pass through the logic below. This
639 // doesn't hurt anything since we still do the trans retry.
640
641 *bits |= 0x00004000;
642
643 // Once the thread leaves thread_in_native_trans for another
644 // thread state, we break out of this retry loop. We shouldn't
645 // need this flag to prevent us from getting back here, but
646 // sometimes paranoia is good.
647 did_trans_retry = true;
648
649 // We wait for the thread to transition to a more usable state.
650 for (int i = 1; i <= SuspendRetryCount; i++) {
651 // We used to do an "os::yield_all(i)" call here with the intention
652 // that yielding would increase on each retry. However, the parameter
653 // is ignored on Linux which means the yield didn't scale up. Waiting
654 // on the SR_lock below provides a much more predictable scale up for
655 // the delay. It also provides a simple/direct point to check for any
656 // safepoint requests from the VMThread
657
658 // temporarily drops SR_lock while doing wait with safepoint check
659 // (if we're a JavaThread - the WatcherThread can also call this)
660 // and increase delay with each retry
661 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
662
663 // check the actual thread state instead of what we saved above
664 if (thread_state() != _thread_in_native_trans) {
665 // the thread has transitioned to another thread state so
666 // try all the checks (except this one) one more time.
667 do_trans_retry = true;
668 break;
669 }
670 } // end retry loop
671
672
673 }
674 } while (do_trans_retry);
675
676 *bits |= 0x00000010;
677 return false;
678 }
679
680 //
681 // Wait for an external suspend request to complete (or be cancelled).
682 // Returns true if the thread is externally suspended and false otherwise.
683 //
684 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
685 uint32_t *bits) {
686 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
687 false /* !called_by_wait */, bits);
688
689 // local flag copies to minimize SR_lock hold time
690 bool is_suspended;
691 bool pending;
692 uint32_t reset_bits;
693
694 // set a marker so is_ext_suspend_completed() knows we are the caller
695 *bits |= 0x00010000;
696
697 // We use reset_bits to reinitialize the bits value at the top of
698 // each retry loop. This allows the caller to make use of any
699 // unused bits for their own marking purposes.
700 reset_bits = *bits;
701
702 {
703 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
704 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
705 delay, bits);
706 pending = is_external_suspend();
707 }
708 // must release SR_lock to allow suspension to complete
709
710 if (!pending) {
711 // A cancelled suspend request is the only false return from
712 // is_ext_suspend_completed() that keeps us from entering the
713 // retry loop.
714 *bits |= 0x00020000;
715 return false;
716 }
717
718 if (is_suspended) {
719 *bits |= 0x00040000;
720 return true;
721 }
722
723 for (int i = 1; i <= retries; i++) {
724 *bits = reset_bits; // reinit to only track last retry
725
726 // We used to do an "os::yield_all(i)" call here with the intention
727 // that yielding would increase on each retry. However, the parameter
728 // is ignored on Linux which means the yield didn't scale up. Waiting
729 // on the SR_lock below provides a much more predictable scale up for
730 // the delay. It also provides a simple/direct point to check for any
731 // safepoint requests from the VMThread
732
733 {
734 MutexLocker ml(SR_lock());
735 // wait with safepoint check (if we're a JavaThread - the WatcherThread
736 // can also call this) and increase delay with each retry
737 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
738
739 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
740 delay, bits);
741
742 // It is possible for the external suspend request to be cancelled
743 // (by a resume) before the actual suspend operation is completed.
744 // Refresh our local copy to see if we still need to wait.
745 pending = is_external_suspend();
746 }
747
748 if (!pending) {
749 // A cancelled suspend request is the only false return from
750 // is_ext_suspend_completed() that keeps us from staying in the
751 // retry loop.
752 *bits |= 0x00080000;
753 return false;
754 }
755
756 if (is_suspended) {
757 *bits |= 0x00100000;
758 return true;
759 }
760 } // end retry loop
761
762 // thread did not suspend after all our retries
763 *bits |= 0x00200000;
764 return false;
765 }
766
767 #ifndef PRODUCT
768 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
769
770 // This should not need to be atomic as the only way for simultaneous
771 // updates is via interrupts. Even then this should be rare or non-existant
772 // and we don't care that much anyway.
773
774 int index = _jmp_ring_index;
775 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
776 _jmp_ring[index]._target = (intptr_t) target;
777 _jmp_ring[index]._instruction = (intptr_t) instr;
778 _jmp_ring[index]._file = file;
779 _jmp_ring[index]._line = line;
780 }
781 #endif /* PRODUCT */
782
783 // Called by flat profiler
784 // Callers have already called wait_for_ext_suspend_completion
785 // The assertion for that is currently too complex to put here:
786 bool JavaThread::profile_last_Java_frame(frame* _fr) {
787 bool gotframe = false;
788 // self suspension saves needed state.
789 if (has_last_Java_frame() && _anchor.walkable()) {
790 *_fr = pd_last_frame();
791 gotframe = true;
792 }
793 return gotframe;
794 }
795
796 void Thread::interrupt(Thread* thread) {
797 trace("interrupt", thread);
798 debug_only(check_for_dangling_thread_pointer(thread);)
799 os::interrupt(thread);
800 }
801
802 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
803 trace("is_interrupted", thread);
804 debug_only(check_for_dangling_thread_pointer(thread);)
805 // Note: If clear_interrupted==false, this simply fetches and
806 // returns the value of the field osthread()->interrupted().
807 return os::is_interrupted(thread, clear_interrupted);
808 }
809
810
811 // GC Support
812 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
813 jint thread_parity = _oops_do_parity;
814 if (thread_parity != strong_roots_parity) {
815 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
816 if (res == thread_parity) {
817 return true;
818 } else {
819 guarantee(res == strong_roots_parity, "Or else what?");
820 assert(SharedHeap::heap()->workers()->active_workers() > 0,
821 "Should only fail when parallel.");
822 return false;
823 }
824 }
825 assert(SharedHeap::heap()->workers()->active_workers() > 0,
826 "Should only fail when parallel.");
827 return false;
828 }
829
830 void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
831 active_handles()->oops_do(f);
832 // Do oop for ThreadShadow
833 f->do_oop((oop*)&_pending_exception);
834 handle_area()->oops_do(f);
835 }
836
837 void Thread::nmethods_do(CodeBlobClosure* cf) {
838 // no nmethods in a generic thread...
839 }
840
841 void Thread::metadata_do(void f(Metadata*)) {
842 if (metadata_handles() != NULL) {
843 for (int i = 0; i< metadata_handles()->length(); i++) {
844 f(metadata_handles()->at(i));
845 }
846 }
847 }
848
849 void Thread::print_on(outputStream* st) const {
850 // get_priority assumes osthread initialized
851 if (osthread() != NULL) {
852 int os_prio;
853 if (os::get_native_priority(this, &os_prio) == OS_OK) {
854 st->print("os_prio=%d ", os_prio);
855 }
856 st->print("tid=" INTPTR_FORMAT " ", this);
857 osthread()->print_on(st);
858 }
859 debug_only(if (WizardMode) print_owned_locks_on(st);)
860 }
861
862 // Thread::print_on_error() is called by fatal error handler. Don't use
863 // any lock or allocate memory.
864 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
865 if (is_VM_thread()) st->print("VMThread");
866 else if (is_Compiler_thread()) st->print("CompilerThread");
867 else if (is_Java_thread()) st->print("JavaThread");
868 else if (is_GC_task_thread()) st->print("GCTaskThread");
869 else if (is_Watcher_thread()) st->print("WatcherThread");
870 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
871 else st->print("Thread");
872
873 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
874 _stack_base - _stack_size, _stack_base);
875
876 if (osthread()) {
877 st->print(" [id=%d]", osthread()->thread_id());
878 }
879 }
880
881 #ifdef ASSERT
882 void Thread::print_owned_locks_on(outputStream* st) const {
883 Monitor *cur = _owned_locks;
884 if (cur == NULL) {
885 st->print(" (no locks) ");
886 } else {
887 st->print_cr(" Locks owned:");
888 while(cur) {
889 cur->print_on(st);
890 cur = cur->next();
891 }
892 }
893 }
894
895 static int ref_use_count = 0;
896
897 bool Thread::owns_locks_but_compiled_lock() const {
898 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
899 if (cur != Compile_lock) return true;
900 }
901 return false;
902 }
903
904
905 #endif
906
907 #ifndef PRODUCT
908
909 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
910 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
911 // no threads which allow_vm_block's are held
912 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
913 // Check if current thread is allowed to block at a safepoint
914 if (!(_allow_safepoint_count == 0))
915 fatal("Possible safepoint reached by thread that does not allow it");
916 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
917 fatal("LEAF method calling lock?");
918 }
919
920 #ifdef ASSERT
921 if (potential_vm_operation && is_Java_thread()
922 && !Universe::is_bootstrapping()) {
923 // Make sure we do not hold any locks that the VM thread also uses.
924 // This could potentially lead to deadlocks
925 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
926 // Threads_lock is special, since the safepoint synchronization will not start before this is
927 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
928 // since it is used to transfer control between JavaThreads and the VMThread
929 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
930 if ( (cur->allow_vm_block() &&
931 cur != Threads_lock &&
932 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
933 cur != VMOperationRequest_lock &&
934 cur != VMOperationQueue_lock) ||
935 cur->rank() == Mutex::special) {
936 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
937 }
938 }
939 }
940
941 if (GCALotAtAllSafepoints) {
942 // We could enter a safepoint here and thus have a gc
943 InterfaceSupport::check_gc_alot();
944 }
945 #endif
946 }
947 #endif
948
949 bool Thread::is_in_stack(address adr) const {
950 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
951 address end = os::current_stack_pointer();
952 // Allow non Java threads to call this without stack_base
953 if (_stack_base == NULL) return true;
954 if (stack_base() >= adr && adr >= end) return true;
955
956 return false;
957 }
958
959
960 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
961 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
962 // used for compilation in the future. If that change is made, the need for these methods
963 // should be revisited, and they should be removed if possible.
964
965 bool Thread::is_lock_owned(address adr) const {
966 return on_local_stack(adr);
967 }
968
969 bool Thread::set_as_starting_thread() {
970 // NOTE: this must be called inside the main thread.
971 return os::create_main_thread((JavaThread*)this);
972 }
973
974 static void initialize_class(Symbol* class_name, TRAPS) {
975 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
976 InstanceKlass::cast(klass)->initialize(CHECK);
977 }
978
979
980 // Creates the initial ThreadGroup
981 static Handle create_initial_thread_group(TRAPS) {
982 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
983 instanceKlassHandle klass (THREAD, k);
984
985 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
986 {
987 JavaValue result(T_VOID);
988 JavaCalls::call_special(&result,
989 system_instance,
990 klass,
991 vmSymbols::object_initializer_name(),
992 vmSymbols::void_method_signature(),
993 CHECK_NH);
994 }
995 Universe::set_system_thread_group(system_instance());
996
997 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
998 {
999 JavaValue result(T_VOID);
1000 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1001 JavaCalls::call_special(&result,
1002 main_instance,
1003 klass,
1004 vmSymbols::object_initializer_name(),
1005 vmSymbols::threadgroup_string_void_signature(),
1006 system_instance,
1007 string,
1008 CHECK_NH);
1009 }
1010 return main_instance;
1011 }
1012
1013 // Creates the initial Thread
1014 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1015 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1016 instanceKlassHandle klass (THREAD, k);
1017 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1018
1019 java_lang_Thread::set_thread(thread_oop(), thread);
1020 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1021 thread->set_threadObj(thread_oop());
1022
1023 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1024
1025 JavaValue result(T_VOID);
1026 JavaCalls::call_special(&result, thread_oop,
1027 klass,
1028 vmSymbols::object_initializer_name(),
1029 vmSymbols::threadgroup_string_void_signature(),
1030 thread_group,
1031 string,
1032 CHECK_NULL);
1033 return thread_oop();
1034 }
1035
1036 static void call_initializeSystemClass(TRAPS) {
1037 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1038 instanceKlassHandle klass (THREAD, k);
1039
1040 JavaValue result(T_VOID);
1041 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1042 vmSymbols::void_method_signature(), CHECK);
1043 }
1044
1045 char java_runtime_name[128] = "";
1046 char java_runtime_version[128] = "";
1047
1048 // extract the JRE name from sun.misc.Version.java_runtime_name
1049 static const char* get_java_runtime_name(TRAPS) {
1050 Klass* 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_name_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_name,
1062 sizeof(java_runtime_name));
1063 return name;
1064 } else {
1065 return NULL;
1066 }
1067 }
1068
1069 // extract the JRE version from sun.misc.Version.java_runtime_version
1070 static const char* get_java_runtime_version(TRAPS) {
1071 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1072 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1073 fieldDescriptor fd;
1074 bool found = k != NULL &&
1075 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1076 vmSymbols::string_signature(), &fd);
1077 if (found) {
1078 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1079 if (name_oop == NULL)
1080 return NULL;
1081 const char* name = java_lang_String::as_utf8_string(name_oop,
1082 java_runtime_version,
1083 sizeof(java_runtime_version));
1084 return name;
1085 } else {
1086 return NULL;
1087 }
1088 }
1089
1090 // General purpose hook into Java code, run once when the VM is initialized.
1091 // The Java library method itself may be changed independently from the VM.
1092 static void call_postVMInitHook(TRAPS) {
1093 Klass* k = SystemDictionary::PostVMInitHook_klass();
1094 instanceKlassHandle klass (THREAD, k);
1095 if (klass.not_null()) {
1096 JavaValue result(T_VOID);
1097 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1098 vmSymbols::void_method_signature(),
1099 CHECK);
1100 }
1101 }
1102
1103 static void reset_vm_info_property(TRAPS) {
1104 // the vm info string
1105 ResourceMark rm(THREAD);
1106 const char *vm_info = VM_Version::vm_info_string();
1107
1108 // java.lang.System class
1109 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1110 instanceKlassHandle klass (THREAD, k);
1111
1112 // setProperty arguments
1113 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1114 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1115
1116 // return value
1117 JavaValue r(T_OBJECT);
1118
1119 // public static String setProperty(String key, String value);
1120 JavaCalls::call_static(&r,
1121 klass,
1122 vmSymbols::setProperty_name(),
1123 vmSymbols::string_string_string_signature(),
1124 key_str,
1125 value_str,
1126 CHECK);
1127 }
1128
1129
1130 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1131 assert(thread_group.not_null(), "thread group should be specified");
1132 assert(threadObj() == NULL, "should only create Java thread object once");
1133
1134 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1135 instanceKlassHandle klass (THREAD, k);
1136 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1137
1138 java_lang_Thread::set_thread(thread_oop(), this);
1139 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1140 set_threadObj(thread_oop());
1141
1142 JavaValue result(T_VOID);
1143 if (thread_name != NULL) {
1144 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1145 // Thread gets assigned specified name and null target
1146 JavaCalls::call_special(&result,
1147 thread_oop,
1148 klass,
1149 vmSymbols::object_initializer_name(),
1150 vmSymbols::threadgroup_string_void_signature(),
1151 thread_group, // Argument 1
1152 name, // Argument 2
1153 THREAD);
1154 } else {
1155 // Thread gets assigned name "Thread-nnn" and null target
1156 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1157 JavaCalls::call_special(&result,
1158 thread_oop,
1159 klass,
1160 vmSymbols::object_initializer_name(),
1161 vmSymbols::threadgroup_runnable_void_signature(),
1162 thread_group, // Argument 1
1163 Handle(), // Argument 2
1164 THREAD);
1165 }
1166
1167
1168 if (daemon) {
1169 java_lang_Thread::set_daemon(thread_oop());
1170 }
1171
1172 if (HAS_PENDING_EXCEPTION) {
1173 return;
1174 }
1175
1176 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1177 Handle threadObj(this, this->threadObj());
1178
1179 JavaCalls::call_special(&result,
1180 thread_group,
1181 group,
1182 vmSymbols::add_method_name(),
1183 vmSymbols::thread_void_signature(),
1184 threadObj, // Arg 1
1185 THREAD);
1186
1187
1188 }
1189
1190 // NamedThread -- non-JavaThread subclasses with multiple
1191 // uniquely named instances should derive from this.
1192 NamedThread::NamedThread() : Thread() {
1193 _name = NULL;
1194 _processed_thread = NULL;
1195 }
1196
1197 NamedThread::~NamedThread() {
1198 if (_name != NULL) {
1199 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1200 _name = NULL;
1201 }
1202 }
1203
1204 void NamedThread::set_name(const char* format, ...) {
1205 guarantee(_name == NULL, "Only get to set name once.");
1206 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1207 guarantee(_name != NULL, "alloc failure");
1208 va_list ap;
1209 va_start(ap, format);
1210 jio_vsnprintf(_name, max_name_len, format, ap);
1211 va_end(ap);
1212 }
1213
1214 // ======= WatcherThread ========
1215
1216 // The watcher thread exists to simulate timer interrupts. It should
1217 // be replaced by an abstraction over whatever native support for
1218 // timer interrupts exists on the platform.
1219
1220 WatcherThread* WatcherThread::_watcher_thread = NULL;
1221 bool WatcherThread::_startable = false;
1222 volatile bool WatcherThread::_should_terminate = false;
1223
1224 WatcherThread::WatcherThread() : Thread() {
1225 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1226 if (os::create_thread(this, os::watcher_thread)) {
1227 _watcher_thread = this;
1228
1229 // Set the watcher thread to the highest OS priority which should not be
1230 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1231 // is created. The only normal thread using this priority is the reference
1232 // handler thread, which runs for very short intervals only.
1233 // If the VMThread's priority is not lower than the WatcherThread profiling
1234 // will be inaccurate.
1235 os::set_priority(this, MaxPriority);
1236 if (!DisableStartThread) {
1237 os::start_thread(this);
1238 }
1239 }
1240 }
1241
1242 int WatcherThread::sleep() const {
1243 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1244
1245 // remaining will be zero if there are no tasks,
1246 // causing the WatcherThread to sleep until a task is
1247 // enrolled
1248 int remaining = PeriodicTask::time_to_wait();
1249 int time_slept = 0;
1250
1251 // we expect this to timeout - we only ever get unparked when
1252 // we should terminate or when a new task has been enrolled
1253 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1254
1255 jlong time_before_loop = os::javaTimeNanos();
1256
1257 for (;;) {
1258 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1259 jlong now = os::javaTimeNanos();
1260
1261 if (remaining == 0) {
1262 // if we didn't have any tasks we could have waited for a long time
1263 // consider the time_slept zero and reset time_before_loop
1264 time_slept = 0;
1265 time_before_loop = now;
1266 } else {
1267 // need to recalulate since we might have new tasks in _tasks
1268 time_slept = (int) ((now - time_before_loop) / 1000000);
1269 }
1270
1271 // Change to task list or spurious wakeup of some kind
1272 if (timedout || _should_terminate) {
1273 break;
1274 }
1275
1276 remaining = PeriodicTask::time_to_wait();
1277 if (remaining == 0) {
1278 // Last task was just disenrolled so loop around and wait until
1279 // another task gets enrolled
1280 continue;
1281 }
1282
1283 remaining -= time_slept;
1284 if (remaining <= 0)
1285 break;
1286 }
1287
1288 return time_slept;
1289 }
1290
1291 void WatcherThread::run() {
1292 assert(this == watcher_thread(), "just checking");
1293
1294 this->record_stack_base_and_size();
1295 this->initialize_thread_local_storage();
1296 this->set_active_handles(JNIHandleBlock::allocate_block());
1297 while(!_should_terminate) {
1298 assert(watcher_thread() == Thread::current(), "thread consistency check");
1299 assert(watcher_thread() == this, "thread consistency check");
1300
1301 // Calculate how long it'll be until the next PeriodicTask work
1302 // should be done, and sleep that amount of time.
1303 int time_waited = sleep();
1304
1305 if (is_error_reported()) {
1306 // A fatal error has happened, the error handler(VMError::report_and_die)
1307 // should abort JVM after creating an error log file. However in some
1308 // rare cases, the error handler itself might deadlock. Here we try to
1309 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1310 //
1311 // This code is in WatcherThread because WatcherThread wakes up
1312 // periodically so the fatal error handler doesn't need to do anything;
1313 // also because the WatcherThread is less likely to crash than other
1314 // threads.
1315
1316 for (;;) {
1317 if (!ShowMessageBoxOnError
1318 && (OnError == NULL || OnError[0] == '\0')
1319 && Arguments::abort_hook() == NULL) {
1320 os::sleep(this, 2 * 60 * 1000, false);
1321 fdStream err(defaultStream::output_fd());
1322 err.print_raw_cr("# [ timer expired, abort... ]");
1323 // skip atexit/vm_exit/vm_abort hooks
1324 os::die();
1325 }
1326
1327 // Wake up 5 seconds later, the fatal handler may reset OnError or
1328 // ShowMessageBoxOnError when it is ready to abort.
1329 os::sleep(this, 5 * 1000, false);
1330 }
1331 }
1332
1333 PeriodicTask::real_time_tick(time_waited);
1334 }
1335
1336 // Signal that it is terminated
1337 {
1338 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1339 _watcher_thread = NULL;
1340 Terminator_lock->notify();
1341 }
1342
1343 // Thread destructor usually does this..
1344 ThreadLocalStorage::set_thread(NULL);
1345 }
1346
1347 void WatcherThread::start() {
1348 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1349
1350 if (watcher_thread() == NULL && _startable) {
1351 _should_terminate = false;
1352 // Create the single instance of WatcherThread
1353 new WatcherThread();
1354 }
1355 }
1356
1357 void WatcherThread::make_startable() {
1358 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1359 _startable = true;
1360 }
1361
1362 void WatcherThread::stop() {
1363 {
1364 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1365 _should_terminate = true;
1366 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1367
1368 WatcherThread* watcher = watcher_thread();
1369 if (watcher != NULL)
1370 watcher->unpark();
1371 }
1372
1373 // it is ok to take late safepoints here, if needed
1374 MutexLocker mu(Terminator_lock);
1375
1376 while(watcher_thread() != NULL) {
1377 // This wait should make safepoint checks, wait without a timeout,
1378 // and wait as a suspend-equivalent condition.
1379 //
1380 // Note: If the FlatProfiler is running, then this thread is waiting
1381 // for the WatcherThread to terminate and the WatcherThread, via the
1382 // FlatProfiler task, is waiting for the external suspend request on
1383 // this thread to complete. wait_for_ext_suspend_completion() will
1384 // eventually timeout, but that takes time. Making this wait a
1385 // suspend-equivalent condition solves that timeout problem.
1386 //
1387 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1388 Mutex::_as_suspend_equivalent_flag);
1389 }
1390 }
1391
1392 void WatcherThread::unpark() {
1393 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1394 PeriodicTask_lock->notify();
1395 }
1396
1397 void WatcherThread::print_on(outputStream* st) const {
1398 st->print("\"%s\" ", name());
1399 Thread::print_on(st);
1400 st->cr();
1401 }
1402
1403 // ======= JavaThread ========
1404
1405 // A JavaThread is a normal Java thread
1406
1407 void JavaThread::initialize() {
1408 // Initialize fields
1409
1410 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1411 set_claimed_par_id(-1);
1412
1413 set_saved_exception_pc(NULL);
1414 set_threadObj(NULL);
1415 _anchor.clear();
1416 set_entry_point(NULL);
1417 set_jni_functions(jni_functions());
1418 set_callee_target(NULL);
1419 set_vm_result(NULL);
1420 set_vm_result_2(NULL);
1421 set_vframe_array_head(NULL);
1422 set_vframe_array_last(NULL);
1423 set_deferred_locals(NULL);
1424 set_deopt_mark(NULL);
1425 set_deopt_nmethod(NULL);
1426 clear_must_deopt_id();
1427 set_monitor_chunks(NULL);
1428 set_next(NULL);
1429 set_thread_state(_thread_new);
1430 #if INCLUDE_NMT
1431 set_recorder(NULL);
1432 #endif
1433 _terminated = _not_terminated;
1434 _privileged_stack_top = NULL;
1435 _array_for_gc = NULL;
1436 _suspend_equivalent = false;
1437 _in_deopt_handler = 0;
1438 _doing_unsafe_access = false;
1439 _stack_guard_state = stack_guard_unused;
1440 _exception_oop = NULL;
1441 _exception_pc = 0;
1442 _exception_handler_pc = 0;
1443 _is_method_handle_return = 0;
1444 _jvmti_thread_state= NULL;
1445 _should_post_on_exceptions_flag = JNI_FALSE;
1446 _jvmti_get_loaded_classes_closure = NULL;
1447 _interp_only_mode = 0;
1448 _special_runtime_exit_condition = _no_async_condition;
1449 _pending_async_exception = NULL;
1450 _is_compiling = false;
1451 _thread_stat = NULL;
1452 _thread_stat = new ThreadStatistics();
1453 _blocked_on_compilation = false;
1454 _jni_active_critical = 0;
1455 _do_not_unlock_if_synchronized = false;
1456 _cached_monitor_info = NULL;
1457 _parker = Parker::Allocate(this) ;
1458
1459 #ifndef PRODUCT
1460 _jmp_ring_index = 0;
1461 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1462 record_jump(NULL, NULL, NULL, 0);
1463 }
1464 #endif /* PRODUCT */
1465
1466 set_thread_profiler(NULL);
1467 if (FlatProfiler::is_active()) {
1468 // This is where we would decide to either give each thread it's own profiler
1469 // or use one global one from FlatProfiler,
1470 // or up to some count of the number of profiled threads, etc.
1471 ThreadProfiler* pp = new ThreadProfiler();
1472 pp->engage();
1473 set_thread_profiler(pp);
1474 }
1475
1476 // Setup safepoint state info for this thread
1477 ThreadSafepointState::create(this);
1478
1479 debug_only(_java_call_counter = 0);
1480
1481 // JVMTI PopFrame support
1482 _popframe_condition = popframe_inactive;
1483 _popframe_preserved_args = NULL;
1484 _popframe_preserved_args_size = 0;
1485
1486 pd_initialize();
1487 }
1488
1489 #if INCLUDE_ALL_GCS
1490 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1491 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1492 #endif // INCLUDE_ALL_GCS
1493
1494 JavaThread::JavaThread(bool is_attaching_via_jni) :
1495 Thread()
1496 #if INCLUDE_ALL_GCS
1497 , _satb_mark_queue(&_satb_mark_queue_set),
1498 _dirty_card_queue(&_dirty_card_queue_set)
1499 #endif // INCLUDE_ALL_GCS
1500 {
1501 initialize();
1502 if (is_attaching_via_jni) {
1503 _jni_attach_state = _attaching_via_jni;
1504 } else {
1505 _jni_attach_state = _not_attaching_via_jni;
1506 }
1507 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1508 _safepoint_visible = false;
1509 }
1510
1511 bool JavaThread::reguard_stack(address cur_sp) {
1512 if (_stack_guard_state != stack_guard_yellow_disabled) {
1513 return true; // Stack already guarded or guard pages not needed.
1514 }
1515
1516 if (register_stack_overflow()) {
1517 // For those architectures which have separate register and
1518 // memory stacks, we must check the register stack to see if
1519 // it has overflowed.
1520 return false;
1521 }
1522
1523 // Java code never executes within the yellow zone: the latter is only
1524 // there to provoke an exception during stack banging. If java code
1525 // is executing there, either StackShadowPages should be larger, or
1526 // some exception code in c1, c2 or the interpreter isn't unwinding
1527 // when it should.
1528 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1529
1530 enable_stack_yellow_zone();
1531 return true;
1532 }
1533
1534 bool JavaThread::reguard_stack(void) {
1535 return reguard_stack(os::current_stack_pointer());
1536 }
1537
1538
1539 void JavaThread::block_if_vm_exited() {
1540 if (_terminated == _vm_exited) {
1541 // _vm_exited is set at safepoint, and Threads_lock is never released
1542 // we will block here forever
1543 Threads_lock->lock_without_safepoint_check();
1544 ShouldNotReachHere();
1545 }
1546 }
1547
1548
1549 // Remove this ifdef when C1 is ported to the compiler interface.
1550 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1551
1552 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1553 Thread()
1554 #if INCLUDE_ALL_GCS
1555 , _satb_mark_queue(&_satb_mark_queue_set),
1556 _dirty_card_queue(&_dirty_card_queue_set)
1557 #endif // INCLUDE_ALL_GCS
1558 {
1559 if (TraceThreadEvents) {
1560 tty->print_cr("creating thread %p", this);
1561 }
1562 initialize();
1563 _jni_attach_state = _not_attaching_via_jni;
1564 set_entry_point(entry_point);
1565 // Create the native thread itself.
1566 // %note runtime_23
1567 os::ThreadType thr_type = os::java_thread;
1568 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1569 os::java_thread;
1570 os::create_thread(this, thr_type, stack_sz);
1571 _safepoint_visible = false;
1572 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1573 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1574 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1575 // the exception consists of creating the exception object & initializing it, initialization
1576 // will leave the VM via a JavaCall and then all locks must be unlocked).
1577 //
1578 // The thread is still suspended when we reach here. Thread must be explicit started
1579 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1580 // by calling Threads:add. The reason why this is not done here, is because the thread
1581 // object must be fully initialized (take a look at JVM_Start)
1582 }
1583
1584 JavaThread::~JavaThread() {
1585 if (TraceThreadEvents) {
1586 tty->print_cr("terminate thread %p", this);
1587 }
1588
1589 // By now, this thread should already be invisible to safepoint,
1590 // and its per-thread recorder also collected.
1591 assert(!is_safepoint_visible(), "wrong state");
1592 #if INCLUDE_NMT
1593 assert(get_recorder() == NULL, "Already collected");
1594 #endif // INCLUDE_NMT
1595
1596 // JSR166 -- return the parker to the free list
1597 Parker::Release(_parker);
1598 _parker = NULL ;
1599
1600 // Free any remaining previous UnrollBlock
1601 vframeArray* old_array = vframe_array_last();
1602
1603 if (old_array != NULL) {
1604 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1605 old_array->set_unroll_block(NULL);
1606 delete old_info;
1607 delete old_array;
1608 }
1609
1610 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1611 if (deferred != NULL) {
1612 // This can only happen if thread is destroyed before deoptimization occurs.
1613 assert(deferred->length() != 0, "empty array!");
1614 do {
1615 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1616 deferred->remove_at(0);
1617 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1618 delete dlv;
1619 } while (deferred->length() != 0);
1620 delete deferred;
1621 }
1622
1623 // All Java related clean up happens in exit
1624 ThreadSafepointState::destroy(this);
1625 if (_thread_profiler != NULL) delete _thread_profiler;
1626 if (_thread_stat != NULL) delete _thread_stat;
1627 }
1628
1629
1630 // The first routine called by a new Java thread
1631 void JavaThread::run() {
1632 // initialize thread-local alloc buffer related fields
1633 this->initialize_tlab();
1634
1635 // used to test validitity of stack trace backs
1636 this->record_base_of_stack_pointer();
1637
1638 // Record real stack base and size.
1639 this->record_stack_base_and_size();
1640
1641 // Initialize thread local storage; set before calling MutexLocker
1642 this->initialize_thread_local_storage();
1643
1644 this->create_stack_guard_pages();
1645
1646 this->cache_global_variables();
1647
1648 // Thread is now sufficient initialized to be handled by the safepoint code as being
1649 // in the VM. Change thread state from _thread_new to _thread_in_vm
1650 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1651
1652 assert(JavaThread::current() == this, "sanity check");
1653 assert(!Thread::current()->owns_locks(), "sanity check");
1654
1655 DTRACE_THREAD_PROBE(start, this);
1656
1657 // This operation might block. We call that after all safepoint checks for a new thread has
1658 // been completed.
1659 this->set_active_handles(JNIHandleBlock::allocate_block());
1660
1661 if (JvmtiExport::should_post_thread_life()) {
1662 JvmtiExport::post_thread_start(this);
1663 }
1664
1665 EventThreadStart event;
1666 if (event.should_commit()) {
1667 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1668 event.commit();
1669 }
1670
1671 // We call another function to do the rest so we are sure that the stack addresses used
1672 // from there will be lower than the stack base just computed
1673 thread_main_inner();
1674
1675 // Note, thread is no longer valid at this point!
1676 }
1677
1678
1679 void JavaThread::thread_main_inner() {
1680 assert(JavaThread::current() == this, "sanity check");
1681 assert(this->threadObj() != NULL, "just checking");
1682
1683 // Execute thread entry point unless this thread has a pending exception
1684 // or has been stopped before starting.
1685 // Note: Due to JVM_StopThread we can have pending exceptions already!
1686 if (!this->has_pending_exception() &&
1687 !java_lang_Thread::is_stillborn(this->threadObj())) {
1688 {
1689 ResourceMark rm(this);
1690 this->set_native_thread_name(this->get_thread_name());
1691 }
1692 HandleMark hm(this);
1693 this->entry_point()(this, this);
1694 }
1695
1696 DTRACE_THREAD_PROBE(stop, this);
1697
1698 this->exit(false);
1699 delete this;
1700 }
1701
1702
1703 static void ensure_join(JavaThread* thread) {
1704 // We do not need to grap the Threads_lock, since we are operating on ourself.
1705 Handle threadObj(thread, thread->threadObj());
1706 assert(threadObj.not_null(), "java thread object must exist");
1707 ObjectLocker lock(threadObj, thread);
1708 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1709 thread->clear_pending_exception();
1710 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1711 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1712 // Clear the native thread instance - this makes isAlive return false and allows the join()
1713 // to complete once we've done the notify_all below
1714 java_lang_Thread::set_thread(threadObj(), NULL);
1715 lock.notify_all(thread);
1716 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1717 thread->clear_pending_exception();
1718 }
1719
1720
1721 // For any new cleanup additions, please check to see if they need to be applied to
1722 // cleanup_failed_attach_current_thread as well.
1723 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1724 assert(this == JavaThread::current(), "thread consistency check");
1725
1726 HandleMark hm(this);
1727 Handle uncaught_exception(this, this->pending_exception());
1728 this->clear_pending_exception();
1729 Handle threadObj(this, this->threadObj());
1730 assert(threadObj.not_null(), "Java thread object should be created");
1731
1732 if (get_thread_profiler() != NULL) {
1733 get_thread_profiler()->disengage();
1734 ResourceMark rm;
1735 get_thread_profiler()->print(get_thread_name());
1736 }
1737
1738
1739 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1740 {
1741 EXCEPTION_MARK;
1742
1743 CLEAR_PENDING_EXCEPTION;
1744 }
1745 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1746 // has to be fixed by a runtime query method
1747 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1748 // JSR-166: change call from from ThreadGroup.uncaughtException to
1749 // java.lang.Thread.dispatchUncaughtException
1750 if (uncaught_exception.not_null()) {
1751 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1752 {
1753 EXCEPTION_MARK;
1754 // Check if the method Thread.dispatchUncaughtException() exists. If so
1755 // call it. Otherwise we have an older library without the JSR-166 changes,
1756 // so call ThreadGroup.uncaughtException()
1757 KlassHandle recvrKlass(THREAD, threadObj->klass());
1758 CallInfo callinfo;
1759 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1760 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1761 vmSymbols::dispatchUncaughtException_name(),
1762 vmSymbols::throwable_void_signature(),
1763 KlassHandle(), false, false, THREAD);
1764 CLEAR_PENDING_EXCEPTION;
1765 methodHandle method = callinfo.selected_method();
1766 if (method.not_null()) {
1767 JavaValue result(T_VOID);
1768 JavaCalls::call_virtual(&result,
1769 threadObj, thread_klass,
1770 vmSymbols::dispatchUncaughtException_name(),
1771 vmSymbols::throwable_void_signature(),
1772 uncaught_exception,
1773 THREAD);
1774 } else {
1775 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1776 JavaValue result(T_VOID);
1777 JavaCalls::call_virtual(&result,
1778 group, thread_group,
1779 vmSymbols::uncaughtException_name(),
1780 vmSymbols::thread_throwable_void_signature(),
1781 threadObj, // Arg 1
1782 uncaught_exception, // Arg 2
1783 THREAD);
1784 }
1785 if (HAS_PENDING_EXCEPTION) {
1786 ResourceMark rm(this);
1787 jio_fprintf(defaultStream::error_stream(),
1788 "\nException: %s thrown from the UncaughtExceptionHandler"
1789 " in thread \"%s\"\n",
1790 pending_exception()->klass()->external_name(),
1791 get_thread_name());
1792 CLEAR_PENDING_EXCEPTION;
1793 }
1794 }
1795 }
1796
1797 // Called before the java thread exit since we want to read info
1798 // from java_lang_Thread object
1799 EventThreadEnd event;
1800 if (event.should_commit()) {
1801 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1802 event.commit();
1803 }
1804
1805 // Call after last event on thread
1806 EVENT_THREAD_EXIT(this);
1807
1808 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1809 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1810 // is deprecated anyhow.
1811 { int count = 3;
1812 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1813 EXCEPTION_MARK;
1814 JavaValue result(T_VOID);
1815 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1816 JavaCalls::call_virtual(&result,
1817 threadObj, thread_klass,
1818 vmSymbols::exit_method_name(),
1819 vmSymbols::void_method_signature(),
1820 THREAD);
1821 CLEAR_PENDING_EXCEPTION;
1822 }
1823 }
1824
1825 // notify JVMTI
1826 if (JvmtiExport::should_post_thread_life()) {
1827 JvmtiExport::post_thread_end(this);
1828 }
1829
1830 // We have notified the agents that we are exiting, before we go on,
1831 // we must check for a pending external suspend request and honor it
1832 // in order to not surprise the thread that made the suspend request.
1833 while (true) {
1834 {
1835 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1836 if (!is_external_suspend()) {
1837 set_terminated(_thread_exiting);
1838 ThreadService::current_thread_exiting(this);
1839 break;
1840 }
1841 // Implied else:
1842 // Things get a little tricky here. We have a pending external
1843 // suspend request, but we are holding the SR_lock so we
1844 // can't just self-suspend. So we temporarily drop the lock
1845 // and then self-suspend.
1846 }
1847
1848 ThreadBlockInVM tbivm(this);
1849 java_suspend_self();
1850
1851 // We're done with this suspend request, but we have to loop around
1852 // and check again. Eventually we will get SR_lock without a pending
1853 // external suspend request and will be able to mark ourselves as
1854 // exiting.
1855 }
1856 // no more external suspends are allowed at this point
1857 } else {
1858 // before_exit() has already posted JVMTI THREAD_END events
1859 }
1860
1861 // Notify waiters on thread object. This has to be done after exit() is called
1862 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1863 // group should have the destroyed bit set before waiters are notified).
1864 ensure_join(this);
1865 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1866
1867 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1868 // held by this thread must be released. A detach operation must only
1869 // get here if there are no Java frames on the stack. Therefore, any
1870 // owned monitors at this point MUST be JNI-acquired monitors which are
1871 // pre-inflated and in the monitor cache.
1872 //
1873 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1874 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1875 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1876 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1877 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1878 }
1879
1880 // These things needs to be done while we are still a Java Thread. Make sure that thread
1881 // is in a consistent state, in case GC happens
1882 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1883
1884 if (active_handles() != NULL) {
1885 JNIHandleBlock* block = active_handles();
1886 set_active_handles(NULL);
1887 JNIHandleBlock::release_block(block);
1888 }
1889
1890 if (free_handle_block() != NULL) {
1891 JNIHandleBlock* block = free_handle_block();
1892 set_free_handle_block(NULL);
1893 JNIHandleBlock::release_block(block);
1894 }
1895
1896 // These have to be removed while this is still a valid thread.
1897 remove_stack_guard_pages();
1898
1899 if (UseTLAB) {
1900 tlab().make_parsable(true); // retire TLAB
1901 }
1902
1903 if (JvmtiEnv::environments_might_exist()) {
1904 JvmtiExport::cleanup_thread(this);
1905 }
1906
1907 // We must flush any deferred card marks before removing a thread from
1908 // the list of active threads.
1909 Universe::heap()->flush_deferred_store_barrier(this);
1910 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1911
1912 #if INCLUDE_ALL_GCS
1913 // We must flush the G1-related buffers before removing a thread
1914 // from the list of active threads. We must do this after any deferred
1915 // card marks have been flushed (above) so that any entries that are
1916 // added to the thread's dirty card queue as a result are not lost.
1917 if (UseG1GC) {
1918 flush_barrier_queues();
1919 }
1920 #endif // INCLUDE_ALL_GCS
1921
1922 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1923 Threads::remove(this);
1924 }
1925
1926 #if INCLUDE_ALL_GCS
1927 // Flush G1-related queues.
1928 void JavaThread::flush_barrier_queues() {
1929 satb_mark_queue().flush();
1930 dirty_card_queue().flush();
1931 }
1932
1933 void JavaThread::initialize_queues() {
1934 assert(!SafepointSynchronize::is_at_safepoint(),
1935 "we should not be at a safepoint");
1936
1937 ObjPtrQueue& satb_queue = satb_mark_queue();
1938 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1939 // The SATB queue should have been constructed with its active
1940 // field set to false.
1941 assert(!satb_queue.is_active(), "SATB queue should not be active");
1942 assert(satb_queue.is_empty(), "SATB queue should be empty");
1943 // If we are creating the thread during a marking cycle, we should
1944 // set the active field of the SATB queue to true.
1945 if (satb_queue_set.is_active()) {
1946 satb_queue.set_active(true);
1947 }
1948
1949 DirtyCardQueue& dirty_queue = dirty_card_queue();
1950 // The dirty card queue should have been constructed with its
1951 // active field set to true.
1952 assert(dirty_queue.is_active(), "dirty card queue should be active");
1953 }
1954 #endif // INCLUDE_ALL_GCS
1955
1956 void JavaThread::cleanup_failed_attach_current_thread() {
1957 if (get_thread_profiler() != NULL) {
1958 get_thread_profiler()->disengage();
1959 ResourceMark rm;
1960 get_thread_profiler()->print(get_thread_name());
1961 }
1962
1963 if (active_handles() != NULL) {
1964 JNIHandleBlock* block = active_handles();
1965 set_active_handles(NULL);
1966 JNIHandleBlock::release_block(block);
1967 }
1968
1969 if (free_handle_block() != NULL) {
1970 JNIHandleBlock* block = free_handle_block();
1971 set_free_handle_block(NULL);
1972 JNIHandleBlock::release_block(block);
1973 }
1974
1975 // These have to be removed while this is still a valid thread.
1976 remove_stack_guard_pages();
1977
1978 if (UseTLAB) {
1979 tlab().make_parsable(true); // retire TLAB, if any
1980 }
1981
1982 #if INCLUDE_ALL_GCS
1983 if (UseG1GC) {
1984 flush_barrier_queues();
1985 }
1986 #endif // INCLUDE_ALL_GCS
1987
1988 Threads::remove(this);
1989 delete this;
1990 }
1991
1992
1993
1994
1995 JavaThread* JavaThread::active() {
1996 Thread* thread = ThreadLocalStorage::thread();
1997 assert(thread != NULL, "just checking");
1998 if (thread->is_Java_thread()) {
1999 return (JavaThread*) thread;
2000 } else {
2001 assert(thread->is_VM_thread(), "this must be a vm thread");
2002 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2003 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2004 assert(ret->is_Java_thread(), "must be a Java thread");
2005 return ret;
2006 }
2007 }
2008
2009 bool JavaThread::is_lock_owned(address adr) const {
2010 if (Thread::is_lock_owned(adr)) return true;
2011
2012 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2013 if (chunk->contains(adr)) return true;
2014 }
2015
2016 return false;
2017 }
2018
2019
2020 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2021 chunk->set_next(monitor_chunks());
2022 set_monitor_chunks(chunk);
2023 }
2024
2025 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2026 guarantee(monitor_chunks() != NULL, "must be non empty");
2027 if (monitor_chunks() == chunk) {
2028 set_monitor_chunks(chunk->next());
2029 } else {
2030 MonitorChunk* prev = monitor_chunks();
2031 while (prev->next() != chunk) prev = prev->next();
2032 prev->set_next(chunk->next());
2033 }
2034 }
2035
2036 // JVM support.
2037
2038 // Note: this function shouldn't block if it's called in
2039 // _thread_in_native_trans state (such as from
2040 // check_special_condition_for_native_trans()).
2041 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2042
2043 if (has_last_Java_frame() && has_async_condition()) {
2044 // If we are at a polling page safepoint (not a poll return)
2045 // then we must defer async exception because live registers
2046 // will be clobbered by the exception path. Poll return is
2047 // ok because the call we a returning from already collides
2048 // with exception handling registers and so there is no issue.
2049 // (The exception handling path kills call result registers but
2050 // this is ok since the exception kills the result anyway).
2051
2052 if (is_at_poll_safepoint()) {
2053 // if the code we are returning to has deoptimized we must defer
2054 // the exception otherwise live registers get clobbered on the
2055 // exception path before deoptimization is able to retrieve them.
2056 //
2057 RegisterMap map(this, false);
2058 frame caller_fr = last_frame().sender(&map);
2059 assert(caller_fr.is_compiled_frame(), "what?");
2060 if (caller_fr.is_deoptimized_frame()) {
2061 if (TraceExceptions) {
2062 ResourceMark rm;
2063 tty->print_cr("deferred async exception at compiled safepoint");
2064 }
2065 return;
2066 }
2067 }
2068 }
2069
2070 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2071 if (condition == _no_async_condition) {
2072 // Conditions have changed since has_special_runtime_exit_condition()
2073 // was called:
2074 // - if we were here only because of an external suspend request,
2075 // then that was taken care of above (or cancelled) so we are done
2076 // - if we were here because of another async request, then it has
2077 // been cleared between the has_special_runtime_exit_condition()
2078 // and now so again we are done
2079 return;
2080 }
2081
2082 // Check for pending async. exception
2083 if (_pending_async_exception != NULL) {
2084 // Only overwrite an already pending exception, if it is not a threadDeath.
2085 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2086
2087 // We cannot call Exceptions::_throw(...) here because we cannot block
2088 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2089
2090 if (TraceExceptions) {
2091 ResourceMark rm;
2092 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2093 if (has_last_Java_frame() ) {
2094 frame f = last_frame();
2095 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2096 }
2097 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2098 }
2099 _pending_async_exception = NULL;
2100 clear_has_async_exception();
2101 }
2102 }
2103
2104 if (check_unsafe_error &&
2105 condition == _async_unsafe_access_error && !has_pending_exception()) {
2106 condition = _no_async_condition; // done
2107 switch (thread_state()) {
2108 case _thread_in_vm:
2109 {
2110 JavaThread* THREAD = this;
2111 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2112 }
2113 case _thread_in_native:
2114 {
2115 ThreadInVMfromNative tiv(this);
2116 JavaThread* THREAD = this;
2117 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2118 }
2119 case _thread_in_Java:
2120 {
2121 ThreadInVMfromJava tiv(this);
2122 JavaThread* THREAD = this;
2123 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2124 }
2125 default:
2126 ShouldNotReachHere();
2127 }
2128 }
2129
2130 assert(condition == _no_async_condition || has_pending_exception() ||
2131 (!check_unsafe_error && condition == _async_unsafe_access_error),
2132 "must have handled the async condition, if no exception");
2133 }
2134
2135 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2136 //
2137 // Check for pending external suspend. Internal suspend requests do
2138 // not use handle_special_runtime_exit_condition().
2139 // If JNIEnv proxies are allowed, don't self-suspend if the target
2140 // thread is not the current thread. In older versions of jdbx, jdbx
2141 // threads could call into the VM with another thread's JNIEnv so we
2142 // can be here operating on behalf of a suspended thread (4432884).
2143 bool do_self_suspend = is_external_suspend_with_lock();
2144 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2145 //
2146 // Because thread is external suspended the safepoint code will count
2147 // thread as at a safepoint. This can be odd because we can be here
2148 // as _thread_in_Java which would normally transition to _thread_blocked
2149 // at a safepoint. We would like to mark the thread as _thread_blocked
2150 // before calling java_suspend_self like all other callers of it but
2151 // we must then observe proper safepoint protocol. (We can't leave
2152 // _thread_blocked with a safepoint in progress). However we can be
2153 // here as _thread_in_native_trans so we can't use a normal transition
2154 // constructor/destructor pair because they assert on that type of
2155 // transition. We could do something like:
2156 //
2157 // JavaThreadState state = thread_state();
2158 // set_thread_state(_thread_in_vm);
2159 // {
2160 // ThreadBlockInVM tbivm(this);
2161 // java_suspend_self()
2162 // }
2163 // set_thread_state(_thread_in_vm_trans);
2164 // if (safepoint) block;
2165 // set_thread_state(state);
2166 //
2167 // but that is pretty messy. Instead we just go with the way the
2168 // code has worked before and note that this is the only path to
2169 // java_suspend_self that doesn't put the thread in _thread_blocked
2170 // mode.
2171
2172 frame_anchor()->make_walkable(this);
2173 java_suspend_self();
2174
2175 // We might be here for reasons in addition to the self-suspend request
2176 // so check for other async requests.
2177 }
2178
2179 if (check_asyncs) {
2180 check_and_handle_async_exceptions();
2181 }
2182 }
2183
2184 void JavaThread::send_thread_stop(oop java_throwable) {
2185 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2186 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2187 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2188
2189 // Do not throw asynchronous exceptions against the compiler thread
2190 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2191 if (is_Compiler_thread()) return;
2192
2193 {
2194 // Actually throw the Throwable against the target Thread - however
2195 // only if there is no thread death exception installed already.
2196 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2197 // If the topmost frame is a runtime stub, then we are calling into
2198 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2199 // must deoptimize the caller before continuing, as the compiled exception handler table
2200 // may not be valid
2201 if (has_last_Java_frame()) {
2202 frame f = last_frame();
2203 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2204 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2205 RegisterMap reg_map(this, UseBiasedLocking);
2206 frame compiled_frame = f.sender(®_map);
2207 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2208 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2209 }
2210 }
2211 }
2212
2213 // Set async. pending exception in thread.
2214 set_pending_async_exception(java_throwable);
2215
2216 if (TraceExceptions) {
2217 ResourceMark rm;
2218 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2219 }
2220 // for AbortVMOnException flag
2221 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2222 }
2223 }
2224
2225
2226 // Interrupt thread so it will wake up from a potential wait()
2227 Thread::interrupt(this);
2228 }
2229
2230 // External suspension mechanism.
2231 //
2232 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2233 // to any VM_locks and it is at a transition
2234 // Self-suspension will happen on the transition out of the vm.
2235 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2236 //
2237 // Guarantees on return:
2238 // + Target thread will not execute any new bytecode (that's why we need to
2239 // force a safepoint)
2240 // + Target thread will not enter any new monitors
2241 //
2242 void JavaThread::java_suspend() {
2243 { MutexLocker mu(Threads_lock);
2244 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2245 return;
2246 }
2247 }
2248
2249 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2250 if (!is_external_suspend()) {
2251 // a racing resume has cancelled us; bail out now
2252 return;
2253 }
2254
2255 // suspend is done
2256 uint32_t debug_bits = 0;
2257 // Warning: is_ext_suspend_completed() may temporarily drop the
2258 // SR_lock to allow the thread to reach a stable thread state if
2259 // it is currently in a transient thread state.
2260 if (is_ext_suspend_completed(false /* !called_by_wait */,
2261 SuspendRetryDelay, &debug_bits) ) {
2262 return;
2263 }
2264 }
2265
2266 VM_ForceSafepoint vm_suspend;
2267 VMThread::execute(&vm_suspend);
2268 }
2269
2270 // Part II of external suspension.
2271 // A JavaThread self suspends when it detects a pending external suspend
2272 // request. This is usually on transitions. It is also done in places
2273 // where continuing to the next transition would surprise the caller,
2274 // e.g., monitor entry.
2275 //
2276 // Returns the number of times that the thread self-suspended.
2277 //
2278 // Note: DO NOT call java_suspend_self() when you just want to block current
2279 // thread. java_suspend_self() is the second stage of cooperative
2280 // suspension for external suspend requests and should only be used
2281 // to complete an external suspend request.
2282 //
2283 int JavaThread::java_suspend_self() {
2284 int ret = 0;
2285
2286 // we are in the process of exiting so don't suspend
2287 if (is_exiting()) {
2288 clear_external_suspend();
2289 return ret;
2290 }
2291
2292 assert(_anchor.walkable() ||
2293 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2294 "must have walkable stack");
2295
2296 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2297
2298 assert(!this->is_ext_suspended(),
2299 "a thread trying to self-suspend should not already be suspended");
2300
2301 if (this->is_suspend_equivalent()) {
2302 // If we are self-suspending as a result of the lifting of a
2303 // suspend equivalent condition, then the suspend_equivalent
2304 // flag is not cleared until we set the ext_suspended flag so
2305 // that wait_for_ext_suspend_completion() returns consistent
2306 // results.
2307 this->clear_suspend_equivalent();
2308 }
2309
2310 // A racing resume may have cancelled us before we grabbed SR_lock
2311 // above. Or another external suspend request could be waiting for us
2312 // by the time we return from SR_lock()->wait(). The thread
2313 // that requested the suspension may already be trying to walk our
2314 // stack and if we return now, we can change the stack out from under
2315 // it. This would be a "bad thing (TM)" and cause the stack walker
2316 // to crash. We stay self-suspended until there are no more pending
2317 // external suspend requests.
2318 while (is_external_suspend()) {
2319 ret++;
2320 this->set_ext_suspended();
2321
2322 // _ext_suspended flag is cleared by java_resume()
2323 while (is_ext_suspended()) {
2324 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2325 }
2326 }
2327
2328 return ret;
2329 }
2330
2331 #ifdef ASSERT
2332 // verify the JavaThread has not yet been published in the Threads::list, and
2333 // hence doesn't need protection from concurrent access at this stage
2334 void JavaThread::verify_not_published() {
2335 if (!Threads_lock->owned_by_self()) {
2336 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2337 assert( !Threads::includes(this),
2338 "java thread shouldn't have been published yet!");
2339 }
2340 else {
2341 assert( !Threads::includes(this),
2342 "java thread shouldn't have been published yet!");
2343 }
2344 }
2345 #endif
2346
2347 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2348 // progress or when _suspend_flags is non-zero.
2349 // Current thread needs to self-suspend if there is a suspend request and/or
2350 // block if a safepoint is in progress.
2351 // Async exception ISN'T checked.
2352 // Note only the ThreadInVMfromNative transition can call this function
2353 // directly and when thread state is _thread_in_native_trans
2354 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2355 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2356
2357 JavaThread *curJT = JavaThread::current();
2358 bool do_self_suspend = thread->is_external_suspend();
2359
2360 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2361
2362 // If JNIEnv proxies are allowed, don't self-suspend if the target
2363 // thread is not the current thread. In older versions of jdbx, jdbx
2364 // threads could call into the VM with another thread's JNIEnv so we
2365 // can be here operating on behalf of a suspended thread (4432884).
2366 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2367 JavaThreadState state = thread->thread_state();
2368
2369 // We mark this thread_blocked state as a suspend-equivalent so
2370 // that a caller to is_ext_suspend_completed() won't be confused.
2371 // The suspend-equivalent state is cleared by java_suspend_self().
2372 thread->set_suspend_equivalent();
2373
2374 // If the safepoint code sees the _thread_in_native_trans state, it will
2375 // wait until the thread changes to other thread state. There is no
2376 // guarantee on how soon we can obtain the SR_lock and complete the
2377 // self-suspend request. It would be a bad idea to let safepoint wait for
2378 // too long. Temporarily change the state to _thread_blocked to
2379 // let the VM thread know that this thread is ready for GC. The problem
2380 // of changing thread state is that safepoint could happen just after
2381 // java_suspend_self() returns after being resumed, and VM thread will
2382 // see the _thread_blocked state. We must check for safepoint
2383 // after restoring the state and make sure we won't leave while a safepoint
2384 // is in progress.
2385 thread->set_thread_state(_thread_blocked);
2386 thread->java_suspend_self();
2387 thread->set_thread_state(state);
2388 // Make sure new state is seen by VM thread
2389 if (os::is_MP()) {
2390 if (UseMembar) {
2391 // Force a fence between the write above and read below
2392 OrderAccess::fence();
2393 } else {
2394 // Must use this rather than serialization page in particular on Windows
2395 InterfaceSupport::serialize_memory(thread);
2396 }
2397 }
2398 }
2399
2400 if (SafepointSynchronize::do_call_back()) {
2401 // If we are safepointing, then block the caller which may not be
2402 // the same as the target thread (see above).
2403 SafepointSynchronize::block(curJT);
2404 }
2405
2406 if (thread->is_deopt_suspend()) {
2407 thread->clear_deopt_suspend();
2408 RegisterMap map(thread, false);
2409 frame f = thread->last_frame();
2410 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2411 f = f.sender(&map);
2412 }
2413 if (f.id() == thread->must_deopt_id()) {
2414 thread->clear_must_deopt_id();
2415 f.deoptimize(thread);
2416 } else {
2417 fatal("missed deoptimization!");
2418 }
2419 }
2420 }
2421
2422 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2423 // progress or when _suspend_flags is non-zero.
2424 // Current thread needs to self-suspend if there is a suspend request and/or
2425 // block if a safepoint is in progress.
2426 // Also check for pending async exception (not including unsafe access error).
2427 // Note only the native==>VM/Java barriers can call this function and when
2428 // thread state is _thread_in_native_trans.
2429 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2430 check_safepoint_and_suspend_for_native_trans(thread);
2431
2432 if (thread->has_async_exception()) {
2433 // We are in _thread_in_native_trans state, don't handle unsafe
2434 // access error since that may block.
2435 thread->check_and_handle_async_exceptions(false);
2436 }
2437 }
2438
2439 // This is a variant of the normal
2440 // check_special_condition_for_native_trans with slightly different
2441 // semantics for use by critical native wrappers. It does all the
2442 // normal checks but also performs the transition back into
2443 // thread_in_Java state. This is required so that critical natives
2444 // can potentially block and perform a GC if they are the last thread
2445 // exiting the GC_locker.
2446 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2447 check_special_condition_for_native_trans(thread);
2448
2449 // Finish the transition
2450 thread->set_thread_state(_thread_in_Java);
2451
2452 if (thread->do_critical_native_unlock()) {
2453 ThreadInVMfromJavaNoAsyncException tiv(thread);
2454 GC_locker::unlock_critical(thread);
2455 thread->clear_critical_native_unlock();
2456 }
2457 }
2458
2459 // We need to guarantee the Threads_lock here, since resumes are not
2460 // allowed during safepoint synchronization
2461 // Can only resume from an external suspension
2462 void JavaThread::java_resume() {
2463 assert_locked_or_safepoint(Threads_lock);
2464
2465 // Sanity check: thread is gone, has started exiting or the thread
2466 // was not externally suspended.
2467 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2468 return;
2469 }
2470
2471 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2472
2473 clear_external_suspend();
2474
2475 if (is_ext_suspended()) {
2476 clear_ext_suspended();
2477 SR_lock()->notify_all();
2478 }
2479 }
2480
2481 void JavaThread::create_stack_guard_pages() {
2482 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2483 address low_addr = stack_base() - stack_size();
2484 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2485
2486 int allocate = os::allocate_stack_guard_pages();
2487 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2488
2489 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2490 warning("Attempt to allocate stack guard pages failed.");
2491 return;
2492 }
2493
2494 if (os::guard_memory((char *) low_addr, len)) {
2495 _stack_guard_state = stack_guard_enabled;
2496 } else {
2497 warning("Attempt to protect stack guard pages failed.");
2498 if (os::uncommit_memory((char *) low_addr, len)) {
2499 warning("Attempt to deallocate stack guard pages failed.");
2500 }
2501 }
2502 }
2503
2504 void JavaThread::remove_stack_guard_pages() {
2505 assert(Thread::current() == this, "from different thread");
2506 if (_stack_guard_state == stack_guard_unused) return;
2507 address low_addr = stack_base() - stack_size();
2508 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2509
2510 if (os::allocate_stack_guard_pages()) {
2511 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2512 _stack_guard_state = stack_guard_unused;
2513 } else {
2514 warning("Attempt to deallocate stack guard pages failed.");
2515 }
2516 } else {
2517 if (_stack_guard_state == stack_guard_unused) return;
2518 if (os::unguard_memory((char *) low_addr, len)) {
2519 _stack_guard_state = stack_guard_unused;
2520 } else {
2521 warning("Attempt to unprotect stack guard pages failed.");
2522 }
2523 }
2524 }
2525
2526 void JavaThread::enable_stack_yellow_zone() {
2527 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2528 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
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 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2535 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2536
2537 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2538 _stack_guard_state = stack_guard_enabled;
2539 } else {
2540 warning("Attempt to guard stack yellow zone failed.");
2541 }
2542 enable_register_stack_guard();
2543 }
2544
2545 void JavaThread::disable_stack_yellow_zone() {
2546 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2547 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2548
2549 // Simply return if called for a thread that does not use guard pages.
2550 if (_stack_guard_state == stack_guard_unused) return;
2551
2552 // The base notation is from the stacks point of view, growing downward.
2553 // We need to adjust it to work correctly with guard_memory()
2554 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2555
2556 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2557 _stack_guard_state = stack_guard_yellow_disabled;
2558 } else {
2559 warning("Attempt to unguard stack yellow zone failed.");
2560 }
2561 disable_register_stack_guard();
2562 }
2563
2564 void JavaThread::enable_stack_red_zone() {
2565 // The base notation is from the stacks point of view, growing downward.
2566 // We need to adjust it to work correctly with guard_memory()
2567 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2568 address base = stack_red_zone_base() - stack_red_zone_size();
2569
2570 guarantee(base < stack_base(),"Error calculating stack red zone");
2571 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2572
2573 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2574 warning("Attempt to guard stack red zone failed.");
2575 }
2576 }
2577
2578 void JavaThread::disable_stack_red_zone() {
2579 // The base notation is from the stacks point of view, growing downward.
2580 // We need to adjust it to work correctly with guard_memory()
2581 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2582 address base = stack_red_zone_base() - stack_red_zone_size();
2583 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2584 warning("Attempt to unguard stack red zone failed.");
2585 }
2586 }
2587
2588 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2589 // ignore is there is no stack
2590 if (!has_last_Java_frame()) return;
2591 // traverse the stack frames. Starts from top frame.
2592 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2593 frame* fr = fst.current();
2594 f(fr, fst.register_map());
2595 }
2596 }
2597
2598
2599 #ifndef PRODUCT
2600 // Deoptimization
2601 // Function for testing deoptimization
2602 void JavaThread::deoptimize() {
2603 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2604 StackFrameStream fst(this, UseBiasedLocking);
2605 bool deopt = false; // Dump stack only if a deopt actually happens.
2606 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2607 // Iterate over all frames in the thread and deoptimize
2608 for(; !fst.is_done(); fst.next()) {
2609 if(fst.current()->can_be_deoptimized()) {
2610
2611 if (only_at) {
2612 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2613 // consists of comma or carriage return separated numbers so
2614 // search for the current bci in that string.
2615 address pc = fst.current()->pc();
2616 nmethod* nm = (nmethod*) fst.current()->cb();
2617 ScopeDesc* sd = nm->scope_desc_at( pc);
2618 char buffer[8];
2619 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2620 size_t len = strlen(buffer);
2621 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2622 while (found != NULL) {
2623 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2624 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2625 // Check that the bci found is bracketed by terminators.
2626 break;
2627 }
2628 found = strstr(found + 1, buffer);
2629 }
2630 if (!found) {
2631 continue;
2632 }
2633 }
2634
2635 if (DebugDeoptimization && !deopt) {
2636 deopt = true; // One-time only print before deopt
2637 tty->print_cr("[BEFORE Deoptimization]");
2638 trace_frames();
2639 trace_stack();
2640 }
2641 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2642 }
2643 }
2644
2645 if (DebugDeoptimization && deopt) {
2646 tty->print_cr("[AFTER Deoptimization]");
2647 trace_frames();
2648 }
2649 }
2650
2651
2652 // Make zombies
2653 void JavaThread::make_zombies() {
2654 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2655 if (fst.current()->can_be_deoptimized()) {
2656 // it is a Java nmethod
2657 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2658 nm->make_not_entrant();
2659 }
2660 }
2661 }
2662 #endif // PRODUCT
2663
2664
2665 void JavaThread::deoptimized_wrt_marked_nmethods() {
2666 if (!has_last_Java_frame()) return;
2667 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2668 StackFrameStream fst(this, UseBiasedLocking);
2669 for(; !fst.is_done(); fst.next()) {
2670 if (fst.current()->should_be_deoptimized()) {
2671 if (LogCompilation && xtty != NULL) {
2672 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2673 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2674 this->name(), nm != NULL ? nm->compile_id() : -1);
2675 }
2676
2677 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2678 }
2679 }
2680 }
2681
2682
2683 // GC support
2684 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2685
2686 void JavaThread::gc_epilogue() {
2687 frames_do(frame_gc_epilogue);
2688 }
2689
2690
2691 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2692
2693 void JavaThread::gc_prologue() {
2694 frames_do(frame_gc_prologue);
2695 }
2696
2697 // If the caller is a NamedThread, then remember, in the current scope,
2698 // the given JavaThread in its _processed_thread field.
2699 class RememberProcessedThread: public StackObj {
2700 NamedThread* _cur_thr;
2701 public:
2702 RememberProcessedThread(JavaThread* jthr) {
2703 Thread* thread = Thread::current();
2704 if (thread->is_Named_thread()) {
2705 _cur_thr = (NamedThread *)thread;
2706 _cur_thr->set_processed_thread(jthr);
2707 } else {
2708 _cur_thr = NULL;
2709 }
2710 }
2711
2712 ~RememberProcessedThread() {
2713 if (_cur_thr) {
2714 _cur_thr->set_processed_thread(NULL);
2715 }
2716 }
2717 };
2718
2719 void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
2720 // Verify that the deferred card marks have been flushed.
2721 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2722
2723 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2724 // since there may be more than one thread using each ThreadProfiler.
2725
2726 // Traverse the GCHandles
2727 Thread::oops_do(f, cld_f, cf);
2728
2729 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2730 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2731
2732 if (has_last_Java_frame()) {
2733 // Record JavaThread to GC thread
2734 RememberProcessedThread rpt(this);
2735
2736 // Traverse the privileged stack
2737 if (_privileged_stack_top != NULL) {
2738 _privileged_stack_top->oops_do(f);
2739 }
2740
2741 // traverse the registered growable array
2742 if (_array_for_gc != NULL) {
2743 for (int index = 0; index < _array_for_gc->length(); index++) {
2744 f->do_oop(_array_for_gc->adr_at(index));
2745 }
2746 }
2747
2748 // Traverse the monitor chunks
2749 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2750 chunk->oops_do(f);
2751 }
2752
2753 // Traverse the execution stack
2754 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2755 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2756 }
2757 }
2758
2759 // callee_target is never live across a gc point so NULL it here should
2760 // it still contain a methdOop.
2761
2762 set_callee_target(NULL);
2763
2764 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2765 // If we have deferred set_locals there might be oops waiting to be
2766 // written
2767 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2768 if (list != NULL) {
2769 for (int i = 0; i < list->length(); i++) {
2770 list->at(i)->oops_do(f);
2771 }
2772 }
2773
2774 // Traverse instance variables at the end since the GC may be moving things
2775 // around using this function
2776 f->do_oop((oop*) &_threadObj);
2777 f->do_oop((oop*) &_vm_result);
2778 f->do_oop((oop*) &_exception_oop);
2779 f->do_oop((oop*) &_pending_async_exception);
2780
2781 if (jvmti_thread_state() != NULL) {
2782 jvmti_thread_state()->oops_do(f);
2783 }
2784 }
2785
2786 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2787 Thread::nmethods_do(cf); // (super method is a no-op)
2788
2789 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2790 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2791
2792 if (has_last_Java_frame()) {
2793 // Traverse the execution stack
2794 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2795 fst.current()->nmethods_do(cf);
2796 }
2797 }
2798 }
2799
2800 void JavaThread::metadata_do(void f(Metadata*)) {
2801 Thread::metadata_do(f);
2802 if (has_last_Java_frame()) {
2803 // Traverse the execution stack to call f() on the methods in the stack
2804 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2805 fst.current()->metadata_do(f);
2806 }
2807 } else if (is_Compiler_thread()) {
2808 // need to walk ciMetadata in current compile tasks to keep alive.
2809 CompilerThread* ct = (CompilerThread*)this;
2810 if (ct->env() != NULL) {
2811 ct->env()->metadata_do(f);
2812 }
2813 }
2814 }
2815
2816 // Printing
2817 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2818 switch (_thread_state) {
2819 case _thread_uninitialized: return "_thread_uninitialized";
2820 case _thread_new: return "_thread_new";
2821 case _thread_new_trans: return "_thread_new_trans";
2822 case _thread_in_native: return "_thread_in_native";
2823 case _thread_in_native_trans: return "_thread_in_native_trans";
2824 case _thread_in_vm: return "_thread_in_vm";
2825 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2826 case _thread_in_Java: return "_thread_in_Java";
2827 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2828 case _thread_blocked: return "_thread_blocked";
2829 case _thread_blocked_trans: return "_thread_blocked_trans";
2830 default: return "unknown thread state";
2831 }
2832 }
2833
2834 #ifndef PRODUCT
2835 void JavaThread::print_thread_state_on(outputStream *st) const {
2836 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2837 };
2838 void JavaThread::print_thread_state() const {
2839 print_thread_state_on(tty);
2840 };
2841 #endif // PRODUCT
2842
2843 // Called by Threads::print() for VM_PrintThreads operation
2844 void JavaThread::print_on(outputStream *st) const {
2845 st->print("\"%s\" ", get_thread_name());
2846 oop thread_oop = threadObj();
2847 if (thread_oop != NULL) {
2848 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2849 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2850 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2851 }
2852 Thread::print_on(st);
2853 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2854 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2855 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2856 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2857 }
2858 #ifndef PRODUCT
2859 print_thread_state_on(st);
2860 _safepoint_state->print_on(st);
2861 #endif // PRODUCT
2862 }
2863
2864 // Called by fatal error handler. The difference between this and
2865 // JavaThread::print() is that we can't grab lock or allocate memory.
2866 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2867 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2868 oop thread_obj = threadObj();
2869 if (thread_obj != NULL) {
2870 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2871 }
2872 st->print(" [");
2873 st->print("%s", _get_thread_state_name(_thread_state));
2874 if (osthread()) {
2875 st->print(", id=%d", osthread()->thread_id());
2876 }
2877 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2878 _stack_base - _stack_size, _stack_base);
2879 st->print("]");
2880 return;
2881 }
2882
2883 // Verification
2884
2885 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2886
2887 void JavaThread::verify() {
2888 // Verify oops in the thread.
2889 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2890
2891 // Verify the stack frames.
2892 frames_do(frame_verify);
2893 }
2894
2895 // CR 6300358 (sub-CR 2137150)
2896 // Most callers of this method assume that it can't return NULL but a
2897 // thread may not have a name whilst it is in the process of attaching to
2898 // the VM - see CR 6412693, and there are places where a JavaThread can be
2899 // seen prior to having it's threadObj set (eg JNI attaching threads and
2900 // if vm exit occurs during initialization). These cases can all be accounted
2901 // for such that this method never returns NULL.
2902 const char* JavaThread::get_thread_name() const {
2903 #ifdef ASSERT
2904 // early safepoints can hit while current thread does not yet have TLS
2905 if (!SafepointSynchronize::is_at_safepoint()) {
2906 Thread *cur = Thread::current();
2907 if (!(cur->is_Java_thread() && cur == this)) {
2908 // Current JavaThreads are allowed to get their own name without
2909 // the Threads_lock.
2910 assert_locked_or_safepoint(Threads_lock);
2911 }
2912 }
2913 #endif // ASSERT
2914 return get_thread_name_string();
2915 }
2916
2917 // Returns a non-NULL representation of this thread's name, or a suitable
2918 // descriptive string if there is no set name
2919 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2920 const char* name_str;
2921 oop thread_obj = threadObj();
2922 if (thread_obj != NULL) {
2923 typeArrayOop name = java_lang_Thread::name(thread_obj);
2924 if (name != NULL) {
2925 if (buf == NULL) {
2926 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2927 }
2928 else {
2929 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2930 }
2931 }
2932 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2933 name_str = "<no-name - thread is attaching>";
2934 }
2935 else {
2936 name_str = Thread::name();
2937 }
2938 }
2939 else {
2940 name_str = Thread::name();
2941 }
2942 assert(name_str != NULL, "unexpected NULL thread name");
2943 return name_str;
2944 }
2945
2946
2947 const char* JavaThread::get_threadgroup_name() const {
2948 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2949 oop thread_obj = threadObj();
2950 if (thread_obj != NULL) {
2951 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2952 if (thread_group != NULL) {
2953 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2954 // ThreadGroup.name can be null
2955 if (name != NULL) {
2956 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2957 return str;
2958 }
2959 }
2960 }
2961 return NULL;
2962 }
2963
2964 const char* JavaThread::get_parent_name() const {
2965 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2966 oop thread_obj = threadObj();
2967 if (thread_obj != NULL) {
2968 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2969 if (thread_group != NULL) {
2970 oop parent = java_lang_ThreadGroup::parent(thread_group);
2971 if (parent != NULL) {
2972 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2973 // ThreadGroup.name can be null
2974 if (name != NULL) {
2975 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2976 return str;
2977 }
2978 }
2979 }
2980 }
2981 return NULL;
2982 }
2983
2984 ThreadPriority JavaThread::java_priority() const {
2985 oop thr_oop = threadObj();
2986 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2987 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2988 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2989 return priority;
2990 }
2991
2992 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2993
2994 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2995 // Link Java Thread object <-> C++ Thread
2996
2997 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2998 // and put it into a new Handle. The Handle "thread_oop" can then
2999 // be used to pass the C++ thread object to other methods.
3000
3001 // Set the Java level thread object (jthread) field of the
3002 // new thread (a JavaThread *) to C++ thread object using the
3003 // "thread_oop" handle.
3004
3005 // Set the thread field (a JavaThread *) of the
3006 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3007
3008 Handle thread_oop(Thread::current(),
3009 JNIHandles::resolve_non_null(jni_thread));
3010 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3011 "must be initialized");
3012 set_threadObj(thread_oop());
3013 java_lang_Thread::set_thread(thread_oop(), this);
3014
3015 if (prio == NoPriority) {
3016 prio = java_lang_Thread::priority(thread_oop());
3017 assert(prio != NoPriority, "A valid priority should be present");
3018 }
3019
3020 // Push the Java priority down to the native thread; needs Threads_lock
3021 Thread::set_priority(this, prio);
3022
3023 // Add the new thread to the Threads list and set it in motion.
3024 // We must have threads lock in order to call Threads::add.
3025 // It is crucial that we do not block before the thread is
3026 // added to the Threads list for if a GC happens, then the java_thread oop
3027 // will not be visited by GC.
3028 Threads::add(this);
3029 }
3030
3031 oop JavaThread::current_park_blocker() {
3032 // Support for JSR-166 locks
3033 oop thread_oop = threadObj();
3034 if (thread_oop != NULL &&
3035 JDK_Version::current().supports_thread_park_blocker()) {
3036 return java_lang_Thread::park_blocker(thread_oop);
3037 }
3038 return NULL;
3039 }
3040
3041
3042 void JavaThread::print_stack_on(outputStream* st) {
3043 if (!has_last_Java_frame()) return;
3044 ResourceMark rm;
3045 HandleMark hm;
3046
3047 RegisterMap reg_map(this);
3048 vframe* start_vf = last_java_vframe(®_map);
3049 int count = 0;
3050 for (vframe* f = start_vf; f; f = f->sender() ) {
3051 if (f->is_java_frame()) {
3052 javaVFrame* jvf = javaVFrame::cast(f);
3053 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3054
3055 // Print out lock information
3056 if (JavaMonitorsInStackTrace) {
3057 jvf->print_lock_info_on(st, count);
3058 }
3059 } else {
3060 // Ignore non-Java frames
3061 }
3062
3063 // Bail-out case for too deep stacks
3064 count++;
3065 if (MaxJavaStackTraceDepth == count) return;
3066 }
3067 }
3068
3069
3070 // JVMTI PopFrame support
3071 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3072 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3073 if (in_bytes(size_in_bytes) != 0) {
3074 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3075 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3076 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3077 }
3078 }
3079
3080 void* JavaThread::popframe_preserved_args() {
3081 return _popframe_preserved_args;
3082 }
3083
3084 ByteSize JavaThread::popframe_preserved_args_size() {
3085 return in_ByteSize(_popframe_preserved_args_size);
3086 }
3087
3088 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3089 int sz = in_bytes(popframe_preserved_args_size());
3090 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3091 return in_WordSize(sz / wordSize);
3092 }
3093
3094 void JavaThread::popframe_free_preserved_args() {
3095 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3096 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3097 _popframe_preserved_args = NULL;
3098 _popframe_preserved_args_size = 0;
3099 }
3100
3101 #ifndef PRODUCT
3102
3103 void JavaThread::trace_frames() {
3104 tty->print_cr("[Describe stack]");
3105 int frame_no = 1;
3106 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3107 tty->print(" %d. ", frame_no++);
3108 fst.current()->print_value_on(tty,this);
3109 tty->cr();
3110 }
3111 }
3112
3113 class PrintAndVerifyOopClosure: public OopClosure {
3114 protected:
3115 template <class T> inline void do_oop_work(T* p) {
3116 oop obj = oopDesc::load_decode_heap_oop(p);
3117 if (obj == NULL) return;
3118 tty->print(INTPTR_FORMAT ": ", p);
3119 if (obj->is_oop_or_null()) {
3120 if (obj->is_objArray()) {
3121 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3122 } else {
3123 obj->print();
3124 }
3125 } else {
3126 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3127 }
3128 tty->cr();
3129 }
3130 public:
3131 virtual void do_oop(oop* p) { do_oop_work(p); }
3132 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3133 };
3134
3135
3136 static void oops_print(frame* f, const RegisterMap *map) {
3137 PrintAndVerifyOopClosure print;
3138 f->print_value();
3139 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3140 }
3141
3142 // Print our all the locations that contain oops and whether they are
3143 // valid or not. This useful when trying to find the oldest frame
3144 // where an oop has gone bad since the frame walk is from youngest to
3145 // oldest.
3146 void JavaThread::trace_oops() {
3147 tty->print_cr("[Trace oops]");
3148 frames_do(oops_print);
3149 }
3150
3151
3152 #ifdef ASSERT
3153 // Print or validate the layout of stack frames
3154 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3155 ResourceMark rm;
3156 PRESERVE_EXCEPTION_MARK;
3157 FrameValues values;
3158 int frame_no = 0;
3159 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3160 fst.current()->describe(values, ++frame_no);
3161 if (depth == frame_no) break;
3162 }
3163 if (validate_only) {
3164 values.validate();
3165 } else {
3166 tty->print_cr("[Describe stack layout]");
3167 values.print(this);
3168 }
3169 }
3170 #endif
3171
3172 void JavaThread::trace_stack_from(vframe* start_vf) {
3173 ResourceMark rm;
3174 int vframe_no = 1;
3175 for (vframe* f = start_vf; f; f = f->sender() ) {
3176 if (f->is_java_frame()) {
3177 javaVFrame::cast(f)->print_activation(vframe_no++);
3178 } else {
3179 f->print();
3180 }
3181 if (vframe_no > StackPrintLimit) {
3182 tty->print_cr("...<more frames>...");
3183 return;
3184 }
3185 }
3186 }
3187
3188
3189 void JavaThread::trace_stack() {
3190 if (!has_last_Java_frame()) return;
3191 ResourceMark rm;
3192 HandleMark hm;
3193 RegisterMap reg_map(this);
3194 trace_stack_from(last_java_vframe(®_map));
3195 }
3196
3197
3198 #endif // PRODUCT
3199
3200
3201 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3202 assert(reg_map != NULL, "a map must be given");
3203 frame f = last_frame();
3204 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3205 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3206 }
3207 return NULL;
3208 }
3209
3210
3211 Klass* JavaThread::security_get_caller_class(int depth) {
3212 vframeStream vfst(this);
3213 vfst.security_get_caller_frame(depth);
3214 if (!vfst.at_end()) {
3215 return vfst.method()->method_holder();
3216 }
3217 return NULL;
3218 }
3219
3220 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3221 assert(thread->is_Compiler_thread(), "must be compiler thread");
3222 CompileBroker::compiler_thread_loop();
3223 }
3224
3225 // Create a CompilerThread
3226 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3227 : JavaThread(&compiler_thread_entry) {
3228 _env = NULL;
3229 _log = NULL;
3230 _task = NULL;
3231 _queue = queue;
3232 _counters = counters;
3233 _buffer_blob = NULL;
3234 _scanned_nmethod = NULL;
3235
3236 #ifndef PRODUCT
3237 _ideal_graph_printer = NULL;
3238 #endif
3239 }
3240
3241 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
3242 JavaThread::oops_do(f, cld_f, cf);
3243 if (_scanned_nmethod != NULL && cf != NULL) {
3244 // Safepoints can occur when the sweeper is scanning an nmethod so
3245 // process it here to make sure it isn't unloaded in the middle of
3246 // a scan.
3247 cf->do_code_blob(_scanned_nmethod);
3248 }
3249 }
3250
3251 // ======= Threads ========
3252
3253 // The Threads class links together all active threads, and provides
3254 // operations over all threads. It is protected by its own Mutex
3255 // lock, which is also used in other contexts to protect thread
3256 // operations from having the thread being operated on from exiting
3257 // and going away unexpectedly (e.g., safepoint synchronization)
3258
3259 JavaThread* Threads::_thread_list = NULL;
3260 int Threads::_number_of_threads = 0;
3261 int Threads::_number_of_non_daemon_threads = 0;
3262 int Threads::_return_code = 0;
3263 size_t JavaThread::_stack_size_at_create = 0;
3264 #ifdef ASSERT
3265 bool Threads::_vm_complete = false;
3266 #endif
3267
3268 // All JavaThreads
3269 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3270
3271 void os_stream();
3272
3273 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3274 void Threads::threads_do(ThreadClosure* tc) {
3275 assert_locked_or_safepoint(Threads_lock);
3276 // ALL_JAVA_THREADS iterates through all JavaThreads
3277 ALL_JAVA_THREADS(p) {
3278 tc->do_thread(p);
3279 }
3280 // Someday we could have a table or list of all non-JavaThreads.
3281 // For now, just manually iterate through them.
3282 tc->do_thread(VMThread::vm_thread());
3283 Universe::heap()->gc_threads_do(tc);
3284 WatcherThread *wt = WatcherThread::watcher_thread();
3285 // Strictly speaking, the following NULL check isn't sufficient to make sure
3286 // the data for WatcherThread is still valid upon being examined. However,
3287 // considering that WatchThread terminates when the VM is on the way to
3288 // exit at safepoint, the chance of the above is extremely small. The right
3289 // way to prevent termination of WatcherThread would be to acquire
3290 // Terminator_lock, but we can't do that without violating the lock rank
3291 // checking in some cases.
3292 if (wt != NULL)
3293 tc->do_thread(wt);
3294
3295 // If CompilerThreads ever become non-JavaThreads, add them here
3296 }
3297
3298 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3299
3300 extern void JDK_Version_init();
3301
3302 // Check version
3303 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3304
3305 // Initialize the output stream module
3306 ostream_init();
3307
3308 // Process java launcher properties.
3309 Arguments::process_sun_java_launcher_properties(args);
3310
3311 // Initialize the os module before using TLS
3312 os::init();
3313
3314 // Initialize system properties.
3315 Arguments::init_system_properties();
3316
3317 // So that JDK version can be used as a discrimintor when parsing arguments
3318 JDK_Version_init();
3319
3320 // Update/Initialize System properties after JDK version number is known
3321 Arguments::init_version_specific_system_properties();
3322
3323 // Parse arguments
3324 jint parse_result = Arguments::parse(args);
3325 if (parse_result != JNI_OK) return parse_result;
3326
3327 if (PauseAtStartup) {
3328 os::pause();
3329 }
3330
3331 #ifndef USDT2
3332 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3333 #else /* USDT2 */
3334 HOTSPOT_VM_INIT_BEGIN();
3335 #endif /* USDT2 */
3336
3337 // Record VM creation timing statistics
3338 TraceVmCreationTime create_vm_timer;
3339 create_vm_timer.start();
3340
3341 // Timing (must come after argument parsing)
3342 TraceTime timer("Create VM", TraceStartupTime);
3343
3344 // Initialize the os module after parsing the args
3345 jint os_init_2_result = os::init_2();
3346 if (os_init_2_result != JNI_OK) return os_init_2_result;
3347
3348 jint adjust_after_os_result = Arguments::adjust_after_os();
3349 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3350
3351 // intialize TLS
3352 ThreadLocalStorage::init();
3353
3354 // Bootstrap native memory tracking, so it can start recording memory
3355 // activities before worker thread is started. This is the first phase
3356 // of bootstrapping, VM is currently running in single-thread mode.
3357 MemTracker::bootstrap_single_thread();
3358
3359 // Initialize output stream logging
3360 ostream_init_log();
3361
3362 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3363 // Must be before create_vm_init_agents()
3364 if (Arguments::init_libraries_at_startup()) {
3365 convert_vm_init_libraries_to_agents();
3366 }
3367
3368 // Launch -agentlib/-agentpath and converted -Xrun agents
3369 if (Arguments::init_agents_at_startup()) {
3370 create_vm_init_agents();
3371 }
3372
3373 // Initialize Threads state
3374 _thread_list = NULL;
3375 _number_of_threads = 0;
3376 _number_of_non_daemon_threads = 0;
3377
3378 // Initialize global data structures and create system classes in heap
3379 vm_init_globals();
3380
3381 // Attach the main thread to this os thread
3382 JavaThread* main_thread = new JavaThread();
3383 main_thread->set_thread_state(_thread_in_vm);
3384 // must do this before set_active_handles and initialize_thread_local_storage
3385 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3386 // change the stack size recorded here to one based on the java thread
3387 // stacksize. This adjusted size is what is used to figure the placement
3388 // of the guard pages.
3389 main_thread->record_stack_base_and_size();
3390 main_thread->initialize_thread_local_storage();
3391
3392 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3393
3394 if (!main_thread->set_as_starting_thread()) {
3395 vm_shutdown_during_initialization(
3396 "Failed necessary internal allocation. Out of swap space");
3397 delete main_thread;
3398 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3399 return JNI_ENOMEM;
3400 }
3401
3402 // Enable guard page *after* os::create_main_thread(), otherwise it would
3403 // crash Linux VM, see notes in os_linux.cpp.
3404 main_thread->create_stack_guard_pages();
3405
3406 // Initialize Java-Level synchronization subsystem
3407 ObjectMonitor::Initialize() ;
3408
3409 // Second phase of bootstrapping, VM is about entering multi-thread mode
3410 MemTracker::bootstrap_multi_thread();
3411
3412 // Initialize global modules
3413 jint status = init_globals();
3414 if (status != JNI_OK) {
3415 delete main_thread;
3416 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3417 return status;
3418 }
3419
3420 // Should be done after the heap is fully created
3421 main_thread->cache_global_variables();
3422
3423 HandleMark hm;
3424
3425 { MutexLocker mu(Threads_lock);
3426 Threads::add(main_thread);
3427 }
3428
3429 // Any JVMTI raw monitors entered in onload will transition into
3430 // real raw monitor. VM is setup enough here for raw monitor enter.
3431 JvmtiExport::transition_pending_onload_raw_monitors();
3432
3433 // Fully start NMT
3434 MemTracker::start();
3435
3436 // Create the VMThread
3437 { TraceTime timer("Start VMThread", TraceStartupTime);
3438 VMThread::create();
3439 Thread* vmthread = VMThread::vm_thread();
3440
3441 if (!os::create_thread(vmthread, os::vm_thread))
3442 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3443
3444 // Wait for the VM thread to become ready, and VMThread::run to initialize
3445 // Monitors can have spurious returns, must always check another state flag
3446 {
3447 MutexLocker ml(Notify_lock);
3448 os::start_thread(vmthread);
3449 while (vmthread->active_handles() == NULL) {
3450 Notify_lock->wait();
3451 }
3452 }
3453 }
3454
3455 assert (Universe::is_fully_initialized(), "not initialized");
3456 if (VerifyDuringStartup) {
3457 // Make sure we're starting with a clean slate.
3458 VM_Verify verify_op;
3459 VMThread::execute(&verify_op);
3460 }
3461
3462 EXCEPTION_MARK;
3463
3464 // At this point, the Universe is initialized, but we have not executed
3465 // any byte code. Now is a good time (the only time) to dump out the
3466 // internal state of the JVM for sharing.
3467 if (DumpSharedSpaces) {
3468 MetaspaceShared::preload_and_dump(CHECK_0);
3469 ShouldNotReachHere();
3470 }
3471
3472 // Always call even when there are not JVMTI environments yet, since environments
3473 // may be attached late and JVMTI must track phases of VM execution
3474 JvmtiExport::enter_start_phase();
3475
3476 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3477 JvmtiExport::post_vm_start();
3478
3479 {
3480 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3481
3482 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3483 create_vm_init_libraries();
3484 }
3485
3486 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3487
3488 if (AggressiveOpts) {
3489 {
3490 // Forcibly initialize java/util/HashMap and mutate the private
3491 // static final "frontCacheEnabled" field before we start creating instances
3492 #ifdef ASSERT
3493 Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3494 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
3495 #endif
3496 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3497 KlassHandle k = KlassHandle(THREAD, k_o);
3498 guarantee(k.not_null(), "Must find java/util/HashMap");
3499 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3500 ik->initialize(CHECK_0);
3501 fieldDescriptor fd;
3502 // Possible we might not find this field; if so, don't break
3503 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3504 k()->java_mirror()->bool_field_put(fd.offset(), true);
3505 }
3506 }
3507
3508 if (UseStringCache) {
3509 // Forcibly initialize java/lang/StringValue and mutate the private
3510 // static final "stringCacheEnabled" field before we start creating instances
3511 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3512 // Possible that StringValue isn't present: if so, silently don't break
3513 if (k_o != NULL) {
3514 KlassHandle k = KlassHandle(THREAD, k_o);
3515 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3516 ik->initialize(CHECK_0);
3517 fieldDescriptor fd;
3518 // Possible we might not find this field: if so, silently don't break
3519 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3520 k()->java_mirror()->bool_field_put(fd.offset(), true);
3521 }
3522 }
3523 }
3524 }
3525
3526 // Initialize java_lang.System (needed before creating the thread)
3527 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3528 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3529 Handle thread_group = create_initial_thread_group(CHECK_0);
3530 Universe::set_main_thread_group(thread_group());
3531 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3532 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3533 main_thread->set_threadObj(thread_object);
3534 // Set thread status to running since main thread has
3535 // been started and running.
3536 java_lang_Thread::set_thread_status(thread_object,
3537 java_lang_Thread::RUNNABLE);
3538
3539 // The VM creates & returns objects of this class. Make sure it's initialized.
3540 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3541
3542 // The VM preresolves methods to these classes. Make sure that they get initialized
3543 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3544 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3545 call_initializeSystemClass(CHECK_0);
3546
3547 // get the Java runtime name after java.lang.System is initialized
3548 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3549 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3550
3551 // an instance of OutOfMemory exception has been allocated earlier
3552 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3553 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3554 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3555 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3556 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3557 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3558 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3559 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3560 }
3561
3562 // See : bugid 4211085.
3563 // Background : the static initializer of java.lang.Compiler tries to read
3564 // property"java.compiler" and read & write property "java.vm.info".
3565 // When a security manager is installed through the command line
3566 // option "-Djava.security.manager", the above properties are not
3567 // readable and the static initializer for java.lang.Compiler fails
3568 // resulting in a NoClassDefFoundError. This can happen in any
3569 // user code which calls methods in java.lang.Compiler.
3570 // Hack : the hack is to pre-load and initialize this class, so that only
3571 // system domains are on the stack when the properties are read.
3572 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3573 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3574 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3575 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3576 // Once that is done, we should remove this hack.
3577 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3578
3579 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3580 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3581 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3582 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3583 // This should also be taken out as soon as 4211383 gets fixed.
3584 reset_vm_info_property(CHECK_0);
3585
3586 quicken_jni_functions();
3587
3588 // Must be run after init_ft which initializes ft_enabled
3589 if (TRACE_INITIALIZE() != JNI_OK) {
3590 vm_exit_during_initialization("Failed to initialize tracing backend");
3591 }
3592
3593 // Set flag that basic initialization has completed. Used by exceptions and various
3594 // debug stuff, that does not work until all basic classes have been initialized.
3595 set_init_completed();
3596
3597 #ifndef USDT2
3598 HS_DTRACE_PROBE(hotspot, vm__init__end);
3599 #else /* USDT2 */
3600 HOTSPOT_VM_INIT_END();
3601 #endif /* USDT2 */
3602
3603 // record VM initialization completion time
3604 #if INCLUDE_MANAGEMENT
3605 Management::record_vm_init_completed();
3606 #endif // INCLUDE_MANAGEMENT
3607
3608 // Compute system loader. Note that this has to occur after set_init_completed, since
3609 // valid exceptions may be thrown in the process.
3610 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3611 // set_init_completed has just been called, causing exceptions not to be shortcut
3612 // anymore. We call vm_exit_during_initialization directly instead.
3613 SystemDictionary::compute_java_system_loader(THREAD);
3614 if (HAS_PENDING_EXCEPTION) {
3615 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3616 }
3617
3618 #if INCLUDE_ALL_GCS
3619 // Support for ConcurrentMarkSweep. This should be cleaned up
3620 // and better encapsulated. The ugly nested if test would go away
3621 // once things are properly refactored. XXX YSR
3622 if (UseConcMarkSweepGC || UseG1GC) {
3623 if (UseConcMarkSweepGC) {
3624 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3625 } else {
3626 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3627 }
3628 if (HAS_PENDING_EXCEPTION) {
3629 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3630 }
3631 }
3632 #endif // INCLUDE_ALL_GCS
3633
3634 // Always call even when there are not JVMTI environments yet, since environments
3635 // may be attached late and JVMTI must track phases of VM execution
3636 JvmtiExport::enter_live_phase();
3637
3638 // Signal Dispatcher needs to be started before VMInit event is posted
3639 os::signal_init();
3640
3641 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3642 if (!DisableAttachMechanism) {
3643 if (StartAttachListener || AttachListener::init_at_startup()) {
3644 AttachListener::init();
3645 }
3646 }
3647
3648 // Launch -Xrun agents
3649 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3650 // back-end can launch with -Xdebug -Xrunjdwp.
3651 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3652 create_vm_init_libraries();
3653 }
3654
3655 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3656 JvmtiExport::post_vm_initialized();
3657
3658 if (TRACE_START() != JNI_OK) {
3659 vm_exit_during_initialization("Failed to start tracing backend.");
3660 }
3661
3662 if (CleanChunkPoolAsync) {
3663 Chunk::start_chunk_pool_cleaner_task();
3664 }
3665
3666 // initialize compiler(s)
3667 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3668 CompileBroker::compilation_init();
3669 #endif
3670
3671 #if INCLUDE_MANAGEMENT
3672 Management::initialize(THREAD);
3673 #endif // INCLUDE_MANAGEMENT
3674
3675 if (HAS_PENDING_EXCEPTION) {
3676 // management agent fails to start possibly due to
3677 // configuration problem and is responsible for printing
3678 // stack trace if appropriate. Simply exit VM.
3679 vm_exit(1);
3680 }
3681
3682 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3683 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3684 if (MemProfiling) MemProfiler::engage();
3685 StatSampler::engage();
3686 if (CheckJNICalls) JniPeriodicChecker::engage();
3687
3688 BiasedLocking::init();
3689
3690 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3691 call_postVMInitHook(THREAD);
3692 // The Java side of PostVMInitHook.run must deal with all
3693 // exceptions and provide means of diagnosis.
3694 if (HAS_PENDING_EXCEPTION) {
3695 CLEAR_PENDING_EXCEPTION;
3696 }
3697 }
3698
3699 {
3700 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3701 // Make sure the watcher thread can be started by WatcherThread::start()
3702 // or by dynamic enrollment.
3703 WatcherThread::make_startable();
3704 // Start up the WatcherThread if there are any periodic tasks
3705 // NOTE: All PeriodicTasks should be registered by now. If they
3706 // aren't, late joiners might appear to start slowly (we might
3707 // take a while to process their first tick).
3708 if (PeriodicTask::num_tasks() > 0) {
3709 WatcherThread::start();
3710 }
3711 }
3712
3713 // Give os specific code one last chance to start
3714 os::init_3();
3715
3716 create_vm_timer.end();
3717 #ifdef ASSERT
3718 _vm_complete = true;
3719 #endif
3720 return JNI_OK;
3721 }
3722
3723 // type for the Agent_OnLoad and JVM_OnLoad entry points
3724 extern "C" {
3725 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3726 }
3727 // Find a command line agent library and return its entry point for
3728 // -agentlib: -agentpath: -Xrun
3729 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3730 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3731 OnLoadEntry_t on_load_entry = NULL;
3732 void *library = agent->os_lib(); // check if we have looked it up before
3733
3734 if (library == NULL) {
3735 char buffer[JVM_MAXPATHLEN];
3736 char ebuf[1024];
3737 const char *name = agent->name();
3738 const char *msg = "Could not find agent library ";
3739
3740 if (agent->is_absolute_path()) {
3741 library = os::dll_load(name, ebuf, sizeof ebuf);
3742 if (library == NULL) {
3743 const char *sub_msg = " in absolute path, with error: ";
3744 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3745 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3746 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3747 // If we can't find the agent, exit.
3748 vm_exit_during_initialization(buf, NULL);
3749 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3750 }
3751 } else {
3752 // Try to load the agent from the standard dll directory
3753 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3754 name)) {
3755 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3756 }
3757 if (library == NULL) { // Try the local directory
3758 char ns[1] = {0};
3759 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3760 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3761 }
3762 if (library == NULL) {
3763 const char *sub_msg = " on the library path, with error: ";
3764 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3765 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3766 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3767 // If we can't find the agent, exit.
3768 vm_exit_during_initialization(buf, NULL);
3769 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3770 }
3771 }
3772 }
3773 agent->set_os_lib(library);
3774 }
3775
3776 // Find the OnLoad function.
3777 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3778 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index]));
3779 if (on_load_entry != NULL) break;
3780 }
3781 return on_load_entry;
3782 }
3783
3784 // Find the JVM_OnLoad entry point
3785 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3786 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3787 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3788 }
3789
3790 // Find the Agent_OnLoad entry point
3791 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3792 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3793 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3794 }
3795
3796 // For backwards compatibility with -Xrun
3797 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3798 // treated like -agentpath:
3799 // Must be called before agent libraries are created
3800 void Threads::convert_vm_init_libraries_to_agents() {
3801 AgentLibrary* agent;
3802 AgentLibrary* next;
3803
3804 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3805 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3806 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3807
3808 // If there is an JVM_OnLoad function it will get called later,
3809 // otherwise see if there is an Agent_OnLoad
3810 if (on_load_entry == NULL) {
3811 on_load_entry = lookup_agent_on_load(agent);
3812 if (on_load_entry != NULL) {
3813 // switch it to the agent list -- so that Agent_OnLoad will be called,
3814 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3815 Arguments::convert_library_to_agent(agent);
3816 } else {
3817 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3818 }
3819 }
3820 }
3821 }
3822
3823 // Create agents for -agentlib: -agentpath: and converted -Xrun
3824 // Invokes Agent_OnLoad
3825 // Called very early -- before JavaThreads exist
3826 void Threads::create_vm_init_agents() {
3827 extern struct JavaVM_ main_vm;
3828 AgentLibrary* agent;
3829
3830 JvmtiExport::enter_onload_phase();
3831
3832 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3833 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3834
3835 if (on_load_entry != NULL) {
3836 // Invoke the Agent_OnLoad function
3837 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3838 if (err != JNI_OK) {
3839 vm_exit_during_initialization("agent library failed to init", agent->name());
3840 }
3841 } else {
3842 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3843 }
3844 }
3845 JvmtiExport::enter_primordial_phase();
3846 }
3847
3848 extern "C" {
3849 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3850 }
3851
3852 void Threads::shutdown_vm_agents() {
3853 // Send any Agent_OnUnload notifications
3854 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3855 extern struct JavaVM_ main_vm;
3856 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3857
3858 // Find the Agent_OnUnload function.
3859 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3860 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3861 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3862
3863 // Invoke the Agent_OnUnload function
3864 if (unload_entry != NULL) {
3865 JavaThread* thread = JavaThread::current();
3866 ThreadToNativeFromVM ttn(thread);
3867 HandleMark hm(thread);
3868 (*unload_entry)(&main_vm);
3869 break;
3870 }
3871 }
3872 }
3873 }
3874
3875 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3876 // Invokes JVM_OnLoad
3877 void Threads::create_vm_init_libraries() {
3878 extern struct JavaVM_ main_vm;
3879 AgentLibrary* agent;
3880
3881 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3882 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3883
3884 if (on_load_entry != NULL) {
3885 // Invoke the JVM_OnLoad function
3886 JavaThread* thread = JavaThread::current();
3887 ThreadToNativeFromVM ttn(thread);
3888 HandleMark hm(thread);
3889 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3890 if (err != JNI_OK) {
3891 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3892 }
3893 } else {
3894 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3895 }
3896 }
3897 }
3898
3899 // Last thread running calls java.lang.Shutdown.shutdown()
3900 void JavaThread::invoke_shutdown_hooks() {
3901 HandleMark hm(this);
3902
3903 // We could get here with a pending exception, if so clear it now.
3904 if (this->has_pending_exception()) {
3905 this->clear_pending_exception();
3906 }
3907
3908 EXCEPTION_MARK;
3909 Klass* k =
3910 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3911 THREAD);
3912 if (k != NULL) {
3913 // SystemDictionary::resolve_or_null will return null if there was
3914 // an exception. If we cannot load the Shutdown class, just don't
3915 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3916 // and finalizers (if runFinalizersOnExit is set) won't be run.
3917 // Note that if a shutdown hook was registered or runFinalizersOnExit
3918 // was called, the Shutdown class would have already been loaded
3919 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3920 instanceKlassHandle shutdown_klass (THREAD, k);
3921 JavaValue result(T_VOID);
3922 JavaCalls::call_static(&result,
3923 shutdown_klass,
3924 vmSymbols::shutdown_method_name(),
3925 vmSymbols::void_method_signature(),
3926 THREAD);
3927 }
3928 CLEAR_PENDING_EXCEPTION;
3929 }
3930
3931 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3932 // the program falls off the end of main(). Another VM exit path is through
3933 // vm_exit() when the program calls System.exit() to return a value or when
3934 // there is a serious error in VM. The two shutdown paths are not exactly
3935 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3936 // and VM_Exit op at VM level.
3937 //
3938 // Shutdown sequence:
3939 // + Shutdown native memory tracking if it is on
3940 // + Wait until we are the last non-daemon thread to execute
3941 // <-- every thing is still working at this moment -->
3942 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3943 // shutdown hooks, run finalizers if finalization-on-exit
3944 // + Call before_exit(), prepare for VM exit
3945 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3946 // currently the only user of this mechanism is File.deleteOnExit())
3947 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3948 // post thread end and vm death events to JVMTI,
3949 // stop signal thread
3950 // + Call JavaThread::exit(), it will:
3951 // > release JNI handle blocks, remove stack guard pages
3952 // > remove this thread from Threads list
3953 // <-- no more Java code from this thread after this point -->
3954 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3955 // the compiler threads at safepoint
3956 // <-- do not use anything that could get blocked by Safepoint -->
3957 // + Disable tracing at JNI/JVM barriers
3958 // + Set _vm_exited flag for threads that are still running native code
3959 // + Delete this thread
3960 // + Call exit_globals()
3961 // > deletes tty
3962 // > deletes PerfMemory resources
3963 // + Return to caller
3964
3965 bool Threads::destroy_vm() {
3966 JavaThread* thread = JavaThread::current();
3967
3968 #ifdef ASSERT
3969 _vm_complete = false;
3970 #endif
3971 // Wait until we are the last non-daemon thread to execute
3972 { MutexLocker nu(Threads_lock);
3973 while (Threads::number_of_non_daemon_threads() > 1 )
3974 // This wait should make safepoint checks, wait without a timeout,
3975 // and wait as a suspend-equivalent condition.
3976 //
3977 // Note: If the FlatProfiler is running and this thread is waiting
3978 // for another non-daemon thread to finish, then the FlatProfiler
3979 // is waiting for the external suspend request on this thread to
3980 // complete. wait_for_ext_suspend_completion() will eventually
3981 // timeout, but that takes time. Making this wait a suspend-
3982 // equivalent condition solves that timeout problem.
3983 //
3984 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3985 Mutex::_as_suspend_equivalent_flag);
3986 }
3987
3988 // Hang forever on exit if we are reporting an error.
3989 if (ShowMessageBoxOnError && is_error_reported()) {
3990 os::infinite_sleep();
3991 }
3992 os::wait_for_keypress_at_exit();
3993
3994 if (JDK_Version::is_jdk12x_version()) {
3995 // We are the last thread running, so check if finalizers should be run.
3996 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3997 HandleMark rm(thread);
3998 Universe::run_finalizers_on_exit();
3999 } else {
4000 // run Java level shutdown hooks
4001 thread->invoke_shutdown_hooks();
4002 }
4003
4004 before_exit(thread);
4005
4006 thread->exit(true);
4007
4008 // Stop VM thread.
4009 {
4010 // 4945125 The vm thread comes to a safepoint during exit.
4011 // GC vm_operations can get caught at the safepoint, and the
4012 // heap is unparseable if they are caught. Grab the Heap_lock
4013 // to prevent this. The GC vm_operations will not be able to
4014 // queue until after the vm thread is dead.
4015 // After this point, we'll never emerge out of the safepoint before
4016 // the VM exits, so concurrent GC threads do not need to be explicitly
4017 // stopped; they remain inactive until the process exits.
4018 // Note: some concurrent G1 threads may be running during a safepoint,
4019 // but these will not be accessing the heap, just some G1-specific side
4020 // data structures that are not accessed by any other threads but them
4021 // after this point in a terminal safepoint.
4022
4023 MutexLocker ml(Heap_lock);
4024
4025 VMThread::wait_for_vm_thread_exit();
4026 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4027 VMThread::destroy();
4028 }
4029
4030 // clean up ideal graph printers
4031 #if defined(COMPILER2) && !defined(PRODUCT)
4032 IdealGraphPrinter::clean_up();
4033 #endif
4034
4035 // Now, all Java threads are gone except daemon threads. Daemon threads
4036 // running Java code or in VM are stopped by the Safepoint. However,
4037 // daemon threads executing native code are still running. But they
4038 // will be stopped at native=>Java/VM barriers. Note that we can't
4039 // simply kill or suspend them, as it is inherently deadlock-prone.
4040
4041 #ifndef PRODUCT
4042 // disable function tracing at JNI/JVM barriers
4043 TraceJNICalls = false;
4044 TraceJVMCalls = false;
4045 TraceRuntimeCalls = false;
4046 #endif
4047
4048 VM_Exit::set_vm_exited();
4049
4050 notify_vm_shutdown();
4051
4052 delete thread;
4053
4054 // exit_globals() will delete tty
4055 exit_globals();
4056
4057 return true;
4058 }
4059
4060
4061 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4062 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4063 return is_supported_jni_version(version);
4064 }
4065
4066
4067 jboolean Threads::is_supported_jni_version(jint version) {
4068 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4069 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4070 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4071 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4072 return JNI_FALSE;
4073 }
4074
4075
4076 void Threads::add(JavaThread* p, bool force_daemon) {
4077 // The threads lock must be owned at this point
4078 assert_locked_or_safepoint(Threads_lock);
4079
4080 // See the comment for this method in thread.hpp for its purpose and
4081 // why it is called here.
4082 p->initialize_queues();
4083 p->set_next(_thread_list);
4084 _thread_list = p;
4085 _number_of_threads++;
4086 oop threadObj = p->threadObj();
4087 bool daemon = true;
4088 // Bootstrapping problem: threadObj can be null for initial
4089 // JavaThread (or for threads attached via JNI)
4090 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4091 _number_of_non_daemon_threads++;
4092 daemon = false;
4093 }
4094
4095 p->set_safepoint_visible(true);
4096
4097 ThreadService::add_thread(p, daemon);
4098
4099 // Possible GC point.
4100 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4101 }
4102
4103 void Threads::remove(JavaThread* p) {
4104 // Extra scope needed for Thread_lock, so we can check
4105 // that we do not remove thread without safepoint code notice
4106 { MutexLocker ml(Threads_lock);
4107
4108 assert(includes(p), "p must be present");
4109
4110 JavaThread* current = _thread_list;
4111 JavaThread* prev = NULL;
4112
4113 while (current != p) {
4114 prev = current;
4115 current = current->next();
4116 }
4117
4118 if (prev) {
4119 prev->set_next(current->next());
4120 } else {
4121 _thread_list = p->next();
4122 }
4123 _number_of_threads--;
4124 oop threadObj = p->threadObj();
4125 bool daemon = true;
4126 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4127 _number_of_non_daemon_threads--;
4128 daemon = false;
4129
4130 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4131 // on destroy_vm will wake up.
4132 if (number_of_non_daemon_threads() == 1)
4133 Threads_lock->notify_all();
4134 }
4135 ThreadService::remove_thread(p, daemon);
4136
4137 // Make sure that safepoint code disregard this thread. This is needed since
4138 // the thread might mess around with locks after this point. This can cause it
4139 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4140 // of this thread since it is removed from the queue.
4141 p->set_terminated_value();
4142
4143 // Now, this thread is not visible to safepoint
4144 p->set_safepoint_visible(false);
4145 // once the thread becomes safepoint invisible, we can not use its per-thread
4146 // recorder. And Threads::do_threads() no longer walks this thread, so we have
4147 // to release its per-thread recorder here.
4148 MemTracker::thread_exiting(p);
4149 } // unlock Threads_lock
4150
4151 // Since Events::log uses a lock, we grab it outside the Threads_lock
4152 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4153 }
4154
4155 // Threads_lock must be held when this is called (or must be called during a safepoint)
4156 bool Threads::includes(JavaThread* p) {
4157 assert(Threads_lock->is_locked(), "sanity check");
4158 ALL_JAVA_THREADS(q) {
4159 if (q == p ) {
4160 return true;
4161 }
4162 }
4163 return false;
4164 }
4165
4166 // Operations on the Threads list for GC. These are not explicitly locked,
4167 // but the garbage collector must provide a safe context for them to run.
4168 // In particular, these things should never be called when the Threads_lock
4169 // is held by some other thread. (Note: the Safepoint abstraction also
4170 // uses the Threads_lock to gurantee this property. It also makes sure that
4171 // all threads gets blocked when exiting or starting).
4172
4173 void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4174 ALL_JAVA_THREADS(p) {
4175 p->oops_do(f, cld_f, cf);
4176 }
4177 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4178 }
4179
4180 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4181 // Introduce a mechanism allowing parallel threads to claim threads as
4182 // root groups. Overhead should be small enough to use all the time,
4183 // even in sequential code.
4184 SharedHeap* sh = SharedHeap::heap();
4185 // Cannot yet substitute active_workers for n_par_threads
4186 // because of G1CollectedHeap::verify() use of
4187 // SharedHeap::process_strong_roots(). n_par_threads == 0 will
4188 // turn off parallelism in process_strong_roots while active_workers
4189 // is being used for parallelism elsewhere.
4190 bool is_par = sh->n_par_threads() > 0;
4191 assert(!is_par ||
4192 (SharedHeap::heap()->n_par_threads() ==
4193 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4194 int cp = SharedHeap::heap()->strong_roots_parity();
4195 ALL_JAVA_THREADS(p) {
4196 if (p->claim_oops_do(is_par, cp)) {
4197 p->oops_do(f, cld_f, cf);
4198 }
4199 }
4200 VMThread* vmt = VMThread::vm_thread();
4201 if (vmt->claim_oops_do(is_par, cp)) {
4202 vmt->oops_do(f, cld_f, cf);
4203 }
4204 }
4205
4206 #if INCLUDE_ALL_GCS
4207 // Used by ParallelScavenge
4208 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4209 ALL_JAVA_THREADS(p) {
4210 q->enqueue(new ThreadRootsTask(p));
4211 }
4212 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4213 }
4214
4215 // Used by Parallel Old
4216 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4217 ALL_JAVA_THREADS(p) {
4218 q->enqueue(new ThreadRootsMarkingTask(p));
4219 }
4220 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4221 }
4222 #endif // INCLUDE_ALL_GCS
4223
4224 void Threads::nmethods_do(CodeBlobClosure* cf) {
4225 ALL_JAVA_THREADS(p) {
4226 p->nmethods_do(cf);
4227 }
4228 VMThread::vm_thread()->nmethods_do(cf);
4229 }
4230
4231 void Threads::metadata_do(void f(Metadata*)) {
4232 ALL_JAVA_THREADS(p) {
4233 p->metadata_do(f);
4234 }
4235 }
4236
4237 void Threads::gc_epilogue() {
4238 ALL_JAVA_THREADS(p) {
4239 p->gc_epilogue();
4240 }
4241 }
4242
4243 void Threads::gc_prologue() {
4244 ALL_JAVA_THREADS(p) {
4245 p->gc_prologue();
4246 }
4247 }
4248
4249 void Threads::deoptimized_wrt_marked_nmethods() {
4250 ALL_JAVA_THREADS(p) {
4251 p->deoptimized_wrt_marked_nmethods();
4252 }
4253 }
4254
4255
4256 // Get count Java threads that are waiting to enter the specified monitor.
4257 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4258 address monitor, bool doLock) {
4259 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4260 "must grab Threads_lock or be at safepoint");
4261 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4262
4263 int i = 0;
4264 {
4265 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4266 ALL_JAVA_THREADS(p) {
4267 if (p->is_Compiler_thread()) continue;
4268
4269 address pending = (address)p->current_pending_monitor();
4270 if (pending == monitor) { // found a match
4271 if (i < count) result->append(p); // save the first count matches
4272 i++;
4273 }
4274 }
4275 }
4276 return result;
4277 }
4278
4279
4280 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4281 assert(doLock ||
4282 Threads_lock->owned_by_self() ||
4283 SafepointSynchronize::is_at_safepoint(),
4284 "must grab Threads_lock or be at safepoint");
4285
4286 // NULL owner means not locked so we can skip the search
4287 if (owner == NULL) return NULL;
4288
4289 {
4290 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4291 ALL_JAVA_THREADS(p) {
4292 // first, see if owner is the address of a Java thread
4293 if (owner == (address)p) return p;
4294 }
4295 }
4296 // Cannot assert on lack of success here since this function may be
4297 // used by code that is trying to report useful problem information
4298 // like deadlock detection.
4299 if (UseHeavyMonitors) return NULL;
4300
4301 //
4302 // If we didn't find a matching Java thread and we didn't force use of
4303 // heavyweight monitors, then the owner is the stack address of the
4304 // Lock Word in the owning Java thread's stack.
4305 //
4306 JavaThread* the_owner = NULL;
4307 {
4308 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4309 ALL_JAVA_THREADS(q) {
4310 if (q->is_lock_owned(owner)) {
4311 the_owner = q;
4312 break;
4313 }
4314 }
4315 }
4316 // cannot assert on lack of success here; see above comment
4317 return the_owner;
4318 }
4319
4320 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4321 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4322 char buf[32];
4323 st->print_cr(os::local_time_string(buf, sizeof(buf)));
4324
4325 st->print_cr("Full thread dump %s (%s %s):",
4326 Abstract_VM_Version::vm_name(),
4327 Abstract_VM_Version::vm_release(),
4328 Abstract_VM_Version::vm_info_string()
4329 );
4330 st->cr();
4331
4332 #if INCLUDE_ALL_GCS
4333 // Dump concurrent locks
4334 ConcurrentLocksDump concurrent_locks;
4335 if (print_concurrent_locks) {
4336 concurrent_locks.dump_at_safepoint();
4337 }
4338 #endif // INCLUDE_ALL_GCS
4339
4340 ALL_JAVA_THREADS(p) {
4341 ResourceMark rm;
4342 p->print_on(st);
4343 if (print_stacks) {
4344 if (internal_format) {
4345 p->trace_stack();
4346 } else {
4347 p->print_stack_on(st);
4348 }
4349 }
4350 st->cr();
4351 #if INCLUDE_ALL_GCS
4352 if (print_concurrent_locks) {
4353 concurrent_locks.print_locks_on(p, st);
4354 }
4355 #endif // INCLUDE_ALL_GCS
4356 }
4357
4358 VMThread::vm_thread()->print_on(st);
4359 st->cr();
4360 Universe::heap()->print_gc_threads_on(st);
4361 WatcherThread* wt = WatcherThread::watcher_thread();
4362 if (wt != NULL) {
4363 wt->print_on(st);
4364 st->cr();
4365 }
4366 CompileBroker::print_compiler_threads_on(st);
4367 st->flush();
4368 }
4369
4370 // Threads::print_on_error() is called by fatal error handler. It's possible
4371 // that VM is not at safepoint and/or current thread is inside signal handler.
4372 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4373 // memory (even in resource area), it might deadlock the error handler.
4374 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4375 bool found_current = false;
4376 st->print_cr("Java Threads: ( => current thread )");
4377 ALL_JAVA_THREADS(thread) {
4378 bool is_current = (current == thread);
4379 found_current = found_current || is_current;
4380
4381 st->print("%s", is_current ? "=>" : " ");
4382
4383 st->print(PTR_FORMAT, thread);
4384 st->print(" ");
4385 thread->print_on_error(st, buf, buflen);
4386 st->cr();
4387 }
4388 st->cr();
4389
4390 st->print_cr("Other Threads:");
4391 if (VMThread::vm_thread()) {
4392 bool is_current = (current == VMThread::vm_thread());
4393 found_current = found_current || is_current;
4394 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4395
4396 st->print(PTR_FORMAT, VMThread::vm_thread());
4397 st->print(" ");
4398 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4399 st->cr();
4400 }
4401 WatcherThread* wt = WatcherThread::watcher_thread();
4402 if (wt != NULL) {
4403 bool is_current = (current == wt);
4404 found_current = found_current || is_current;
4405 st->print("%s", is_current ? "=>" : " ");
4406
4407 st->print(PTR_FORMAT, wt);
4408 st->print(" ");
4409 wt->print_on_error(st, buf, buflen);
4410 st->cr();
4411 }
4412 if (!found_current) {
4413 st->cr();
4414 st->print("=>" PTR_FORMAT " (exited) ", current);
4415 current->print_on_error(st, buf, buflen);
4416 st->cr();
4417 }
4418 }
4419
4420 // Internal SpinLock and Mutex
4421 // Based on ParkEvent
4422
4423 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4424 //
4425 // We employ SpinLocks _only for low-contention, fixed-length
4426 // short-duration critical sections where we're concerned
4427 // about native mutex_t or HotSpot Mutex:: latency.
4428 // The mux construct provides a spin-then-block mutual exclusion
4429 // mechanism.
4430 //
4431 // Testing has shown that contention on the ListLock guarding gFreeList
4432 // is common. If we implement ListLock as a simple SpinLock it's common
4433 // for the JVM to devolve to yielding with little progress. This is true
4434 // despite the fact that the critical sections protected by ListLock are
4435 // extremely short.
4436 //
4437 // TODO-FIXME: ListLock should be of type SpinLock.
4438 // We should make this a 1st-class type, integrated into the lock
4439 // hierarchy as leaf-locks. Critically, the SpinLock structure
4440 // should have sufficient padding to avoid false-sharing and excessive
4441 // cache-coherency traffic.
4442
4443
4444 typedef volatile int SpinLockT ;
4445
4446 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4447 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4448 return ; // normal fast-path return
4449 }
4450
4451 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4452 TEVENT (SpinAcquire - ctx) ;
4453 int ctr = 0 ;
4454 int Yields = 0 ;
4455 for (;;) {
4456 while (*adr != 0) {
4457 ++ctr ;
4458 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4459 if (Yields > 5) {
4460 // Consider using a simple NakedSleep() instead.
4461 // Then SpinAcquire could be called by non-JVM threads
4462 Thread::current()->_ParkEvent->park(1) ;
4463 } else {
4464 os::NakedYield() ;
4465 ++Yields ;
4466 }
4467 } else {
4468 SpinPause() ;
4469 }
4470 }
4471 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4472 }
4473 }
4474
4475 void Thread::SpinRelease (volatile int * adr) {
4476 assert (*adr != 0, "invariant") ;
4477 OrderAccess::fence() ; // guarantee at least release consistency.
4478 // Roach-motel semantics.
4479 // It's safe if subsequent LDs and STs float "up" into the critical section,
4480 // but prior LDs and STs within the critical section can't be allowed
4481 // to reorder or float past the ST that releases the lock.
4482 *adr = 0 ;
4483 }
4484
4485 // muxAcquire and muxRelease:
4486 //
4487 // * muxAcquire and muxRelease support a single-word lock-word construct.
4488 // The LSB of the word is set IFF the lock is held.
4489 // The remainder of the word points to the head of a singly-linked list
4490 // of threads blocked on the lock.
4491 //
4492 // * The current implementation of muxAcquire-muxRelease uses its own
4493 // dedicated Thread._MuxEvent instance. If we're interested in
4494 // minimizing the peak number of extant ParkEvent instances then
4495 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4496 // as certain invariants were satisfied. Specifically, care would need
4497 // to be taken with regards to consuming unpark() "permits".
4498 // A safe rule of thumb is that a thread would never call muxAcquire()
4499 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4500 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4501 // consume an unpark() permit intended for monitorenter, for instance.
4502 // One way around this would be to widen the restricted-range semaphore
4503 // implemented in park(). Another alternative would be to provide
4504 // multiple instances of the PlatformEvent() for each thread. One
4505 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4506 //
4507 // * Usage:
4508 // -- Only as leaf locks
4509 // -- for short-term locking only as muxAcquire does not perform
4510 // thread state transitions.
4511 //
4512 // Alternatives:
4513 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4514 // but with parking or spin-then-park instead of pure spinning.
4515 // * Use Taura-Oyama-Yonenzawa locks.
4516 // * It's possible to construct a 1-0 lock if we encode the lockword as
4517 // (List,LockByte). Acquire will CAS the full lockword while Release
4518 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4519 // acquiring threads use timers (ParkTimed) to detect and recover from
4520 // the stranding window. Thread/Node structures must be aligned on 256-byte
4521 // boundaries by using placement-new.
4522 // * Augment MCS with advisory back-link fields maintained with CAS().
4523 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4524 // The validity of the backlinks must be ratified before we trust the value.
4525 // If the backlinks are invalid the exiting thread must back-track through the
4526 // the forward links, which are always trustworthy.
4527 // * Add a successor indication. The LockWord is currently encoded as
4528 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4529 // to provide the usual futile-wakeup optimization.
4530 // See RTStt for details.
4531 // * Consider schedctl.sc_nopreempt to cover the critical section.
4532 //
4533
4534
4535 typedef volatile intptr_t MutexT ; // Mux Lock-word
4536 enum MuxBits { LOCKBIT = 1 } ;
4537
4538 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4539 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4540 if (w == 0) return ;
4541 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4542 return ;
4543 }
4544
4545 TEVENT (muxAcquire - Contention) ;
4546 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4547 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4548 for (;;) {
4549 int its = (os::is_MP() ? 100 : 0) + 1 ;
4550
4551 // Optional spin phase: spin-then-park strategy
4552 while (--its >= 0) {
4553 w = *Lock ;
4554 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4555 return ;
4556 }
4557 }
4558
4559 Self->reset() ;
4560 Self->OnList = intptr_t(Lock) ;
4561 // The following fence() isn't _strictly necessary as the subsequent
4562 // CAS() both serializes execution and ratifies the fetched *Lock value.
4563 OrderAccess::fence();
4564 for (;;) {
4565 w = *Lock ;
4566 if ((w & LOCKBIT) == 0) {
4567 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4568 Self->OnList = 0 ; // hygiene - allows stronger asserts
4569 return ;
4570 }
4571 continue ; // Interference -- *Lock changed -- Just retry
4572 }
4573 assert (w & LOCKBIT, "invariant") ;
4574 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4575 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4576 }
4577
4578 while (Self->OnList != 0) {
4579 Self->park() ;
4580 }
4581 }
4582 }
4583
4584 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4585 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4586 if (w == 0) return ;
4587 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4588 return ;
4589 }
4590
4591 TEVENT (muxAcquire - Contention) ;
4592 ParkEvent * ReleaseAfter = NULL ;
4593 if (ev == NULL) {
4594 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4595 }
4596 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4597 for (;;) {
4598 guarantee (ev->OnList == 0, "invariant") ;
4599 int its = (os::is_MP() ? 100 : 0) + 1 ;
4600
4601 // Optional spin phase: spin-then-park strategy
4602 while (--its >= 0) {
4603 w = *Lock ;
4604 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4605 if (ReleaseAfter != NULL) {
4606 ParkEvent::Release (ReleaseAfter) ;
4607 }
4608 return ;
4609 }
4610 }
4611
4612 ev->reset() ;
4613 ev->OnList = intptr_t(Lock) ;
4614 // The following fence() isn't _strictly necessary as the subsequent
4615 // CAS() both serializes execution and ratifies the fetched *Lock value.
4616 OrderAccess::fence();
4617 for (;;) {
4618 w = *Lock ;
4619 if ((w & LOCKBIT) == 0) {
4620 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4621 ev->OnList = 0 ;
4622 // We call ::Release while holding the outer lock, thus
4623 // artificially lengthening the critical section.
4624 // Consider deferring the ::Release() until the subsequent unlock(),
4625 // after we've dropped the outer lock.
4626 if (ReleaseAfter != NULL) {
4627 ParkEvent::Release (ReleaseAfter) ;
4628 }
4629 return ;
4630 }
4631 continue ; // Interference -- *Lock changed -- Just retry
4632 }
4633 assert (w & LOCKBIT, "invariant") ;
4634 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4635 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4636 }
4637
4638 while (ev->OnList != 0) {
4639 ev->park() ;
4640 }
4641 }
4642 }
4643
4644 // Release() must extract a successor from the list and then wake that thread.
4645 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4646 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4647 // Release() would :
4648 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4649 // (B) Extract a successor from the private list "in-hand"
4650 // (C) attempt to CAS() the residual back into *Lock over null.
4651 // If there were any newly arrived threads and the CAS() would fail.
4652 // In that case Release() would detach the RATs, re-merge the list in-hand
4653 // with the RATs and repeat as needed. Alternately, Release() might
4654 // detach and extract a successor, but then pass the residual list to the wakee.
4655 // The wakee would be responsible for reattaching and remerging before it
4656 // competed for the lock.
4657 //
4658 // Both "pop" and DMR are immune from ABA corruption -- there can be
4659 // multiple concurrent pushers, but only one popper or detacher.
4660 // This implementation pops from the head of the list. This is unfair,
4661 // but tends to provide excellent throughput as hot threads remain hot.
4662 // (We wake recently run threads first).
4663
4664 void Thread::muxRelease (volatile intptr_t * Lock) {
4665 for (;;) {
4666 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4667 assert (w & LOCKBIT, "invariant") ;
4668 if (w == LOCKBIT) return ;
4669 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4670 assert (List != NULL, "invariant") ;
4671 assert (List->OnList == intptr_t(Lock), "invariant") ;
4672 ParkEvent * nxt = List->ListNext ;
4673
4674 // The following CAS() releases the lock and pops the head element.
4675 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4676 continue ;
4677 }
4678 List->OnList = 0 ;
4679 OrderAccess::fence() ;
4680 List->unpark () ;
4681 return ;
4682 }
4683 }
4684
4685
4686 void Threads::verify() {
4687 ALL_JAVA_THREADS(p) {
4688 p->verify();
4689 }
4690 VMThread* thread = VMThread::vm_thread();
4691 if (thread != NULL) thread->verify();
4692 }