Wed, 11 Jan 2012 17:34:02 -0500
7115199: Add event tracing hooks and Java Flight Recorder infrastructure
Summary: Added a nop tracing infrastructure, JFR makefile changes and other infrastructure used only by JFR.
Reviewed-by: acorn, sspitsyn
Contributed-by: markus.gronlund@oracle.com
1 /*
2 * Copyright (c) 1997, 2011, 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 */
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/oopFactory.hpp"
37 #include "memory/universe.inline.hpp"
38 #include "oops/instanceKlass.hpp"
39 #include "oops/objArrayOop.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "oops/symbol.hpp"
42 #include "prims/jvm_misc.hpp"
43 #include "prims/jvmtiExport.hpp"
44 #include "prims/jvmtiThreadState.hpp"
45 #include "prims/privilegedStack.hpp"
46 #include "runtime/aprofiler.hpp"
47 #include "runtime/arguments.hpp"
48 #include "runtime/biasedLocking.hpp"
49 #include "runtime/deoptimization.hpp"
50 #include "runtime/fprofiler.hpp"
51 #include "runtime/frame.inline.hpp"
52 #include "runtime/init.hpp"
53 #include "runtime/interfaceSupport.hpp"
54 #include "runtime/java.hpp"
55 #include "runtime/javaCalls.hpp"
56 #include "runtime/jniPeriodicChecker.hpp"
57 #include "runtime/memprofiler.hpp"
58 #include "runtime/mutexLocker.hpp"
59 #include "runtime/objectMonitor.hpp"
60 #include "runtime/osThread.hpp"
61 #include "runtime/safepoint.hpp"
62 #include "runtime/sharedRuntime.hpp"
63 #include "runtime/statSampler.hpp"
64 #include "runtime/stubRoutines.hpp"
65 #include "runtime/task.hpp"
66 #include "runtime/threadCritical.hpp"
67 #include "runtime/threadLocalStorage.hpp"
68 #include "runtime/vframe.hpp"
69 #include "runtime/vframeArray.hpp"
70 #include "runtime/vframe_hp.hpp"
71 #include "runtime/vmThread.hpp"
72 #include "runtime/vm_operations.hpp"
73 #include "services/attachListener.hpp"
74 #include "services/management.hpp"
75 #include "services/threadService.hpp"
76 #include "trace/traceEventTypes.hpp"
77 #include "utilities/defaultStream.hpp"
78 #include "utilities/dtrace.hpp"
79 #include "utilities/events.hpp"
80 #include "utilities/preserveException.hpp"
81 #ifdef TARGET_OS_FAMILY_linux
82 # include "os_linux.inline.hpp"
83 # include "thread_linux.inline.hpp"
84 #endif
85 #ifdef TARGET_OS_FAMILY_solaris
86 # include "os_solaris.inline.hpp"
87 # include "thread_solaris.inline.hpp"
88 #endif
89 #ifdef TARGET_OS_FAMILY_windows
90 # include "os_windows.inline.hpp"
91 # include "thread_windows.inline.hpp"
92 #endif
93 #ifdef TARGET_OS_FAMILY_bsd
94 # include "os_bsd.inline.hpp"
95 # include "thread_bsd.inline.hpp"
96 #endif
97 #ifndef SERIALGC
98 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
99 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
100 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
101 #endif
102 #ifdef COMPILER1
103 #include "c1/c1_Compiler.hpp"
104 #endif
105 #ifdef COMPILER2
106 #include "opto/c2compiler.hpp"
107 #include "opto/idealGraphPrinter.hpp"
108 #endif
110 #ifdef DTRACE_ENABLED
112 // Only bother with this argument setup if dtrace is available
114 #ifndef USDT2
115 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
116 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
117 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
118 intptr_t, intptr_t, bool);
119 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
120 intptr_t, intptr_t, bool);
122 #define DTRACE_THREAD_PROBE(probe, javathread) \
123 { \
124 ResourceMark rm(this); \
125 int len = 0; \
126 const char* name = (javathread)->get_thread_name(); \
127 len = strlen(name); \
128 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
129 name, len, \
130 java_lang_Thread::thread_id((javathread)->threadObj()), \
131 (javathread)->osthread()->thread_id(), \
132 java_lang_Thread::is_daemon((javathread)->threadObj())); \
133 }
135 #else /* USDT2 */
137 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
138 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
140 #define DTRACE_THREAD_PROBE(probe, javathread) \
141 { \
142 ResourceMark rm(this); \
143 int len = 0; \
144 const char* name = (javathread)->get_thread_name(); \
145 len = strlen(name); \
146 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
147 (char *) name, len, \
148 java_lang_Thread::thread_id((javathread)->threadObj()), \
149 (uintptr_t) (javathread)->osthread()->thread_id(), \
150 java_lang_Thread::is_daemon((javathread)->threadObj())); \
151 }
153 #endif /* USDT2 */
155 #else // ndef DTRACE_ENABLED
157 #define DTRACE_THREAD_PROBE(probe, javathread)
159 #endif // ndef DTRACE_ENABLED
161 // Class hierarchy
162 // - Thread
163 // - VMThread
164 // - WatcherThread
165 // - ConcurrentMarkSweepThread
166 // - JavaThread
167 // - CompilerThread
169 // ======= Thread ========
171 // Support for forcing alignment of thread objects for biased locking
172 void* Thread::operator new(size_t size) {
173 if (UseBiasedLocking) {
174 const int alignment = markOopDesc::biased_lock_alignment;
175 size_t aligned_size = size + (alignment - sizeof(intptr_t));
176 void* real_malloc_addr = CHeapObj::operator new(aligned_size);
177 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
178 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
179 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
180 "JavaThread alignment code overflowed allocated storage");
181 if (TraceBiasedLocking) {
182 if (aligned_addr != real_malloc_addr)
183 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
184 real_malloc_addr, aligned_addr);
185 }
186 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
187 return aligned_addr;
188 } else {
189 return CHeapObj::operator new(size);
190 }
191 }
193 void Thread::operator delete(void* p) {
194 if (UseBiasedLocking) {
195 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
196 CHeapObj::operator delete(real_malloc_addr);
197 } else {
198 CHeapObj::operator delete(p);
199 }
200 }
203 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
204 // JavaThread
207 Thread::Thread() {
208 // stack and get_thread
209 set_stack_base(NULL);
210 set_stack_size(0);
211 set_self_raw_id(0);
212 set_lgrp_id(-1);
214 // allocated data structures
215 set_osthread(NULL);
216 set_resource_area(new ResourceArea());
217 set_handle_area(new HandleArea(NULL));
218 set_active_handles(NULL);
219 set_free_handle_block(NULL);
220 set_last_handle_mark(NULL);
222 // This initial value ==> never claimed.
223 _oops_do_parity = 0;
225 // the handle mark links itself to last_handle_mark
226 new HandleMark(this);
228 // plain initialization
229 debug_only(_owned_locks = NULL;)
230 debug_only(_allow_allocation_count = 0;)
231 NOT_PRODUCT(_allow_safepoint_count = 0;)
232 NOT_PRODUCT(_skip_gcalot = false;)
233 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
234 _jvmti_env_iteration_count = 0;
235 set_allocated_bytes(0);
236 set_trace_buffer(NULL);
237 _vm_operation_started_count = 0;
238 _vm_operation_completed_count = 0;
239 _current_pending_monitor = NULL;
240 _current_pending_monitor_is_from_java = true;
241 _current_waiting_monitor = NULL;
242 _num_nested_signal = 0;
243 omFreeList = NULL ;
244 omFreeCount = 0 ;
245 omFreeProvision = 32 ;
246 omInUseList = NULL ;
247 omInUseCount = 0 ;
249 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
250 _suspend_flags = 0;
252 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
253 _hashStateX = os::random() ;
254 _hashStateY = 842502087 ;
255 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
256 _hashStateW = 273326509 ;
258 _OnTrap = 0 ;
259 _schedctl = NULL ;
260 _Stalled = 0 ;
261 _TypeTag = 0x2BAD ;
263 // Many of the following fields are effectively final - immutable
264 // Note that nascent threads can't use the Native Monitor-Mutex
265 // construct until the _MutexEvent is initialized ...
266 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
267 // we might instead use a stack of ParkEvents that we could provision on-demand.
268 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
269 // and ::Release()
270 _ParkEvent = ParkEvent::Allocate (this) ;
271 _SleepEvent = ParkEvent::Allocate (this) ;
272 _MutexEvent = ParkEvent::Allocate (this) ;
273 _MuxEvent = ParkEvent::Allocate (this) ;
275 #ifdef CHECK_UNHANDLED_OOPS
276 if (CheckUnhandledOops) {
277 _unhandled_oops = new UnhandledOops(this);
278 }
279 #endif // CHECK_UNHANDLED_OOPS
280 #ifdef ASSERT
281 if (UseBiasedLocking) {
282 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
283 assert(this == _real_malloc_address ||
284 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
285 "bug in forced alignment of thread objects");
286 }
287 #endif /* ASSERT */
288 }
290 void Thread::initialize_thread_local_storage() {
291 // Note: Make sure this method only calls
292 // non-blocking operations. Otherwise, it might not work
293 // with the thread-startup/safepoint interaction.
295 // During Java thread startup, safepoint code should allow this
296 // method to complete because it may need to allocate memory to
297 // store information for the new thread.
299 // initialize structure dependent on thread local storage
300 ThreadLocalStorage::set_thread(this);
302 // set up any platform-specific state.
303 os::initialize_thread();
305 }
307 void Thread::record_stack_base_and_size() {
308 set_stack_base(os::current_stack_base());
309 set_stack_size(os::current_stack_size());
310 }
313 Thread::~Thread() {
314 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
315 ObjectSynchronizer::omFlush (this) ;
317 // deallocate data structures
318 delete resource_area();
319 // since the handle marks are using the handle area, we have to deallocated the root
320 // handle mark before deallocating the thread's handle area,
321 assert(last_handle_mark() != NULL, "check we have an element");
322 delete last_handle_mark();
323 assert(last_handle_mark() == NULL, "check we have reached the end");
325 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
326 // We NULL out the fields for good hygiene.
327 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
328 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
329 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
330 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
332 delete handle_area();
334 // osthread() can be NULL, if creation of thread failed.
335 if (osthread() != NULL) os::free_thread(osthread());
337 delete _SR_lock;
339 // clear thread local storage if the Thread is deleting itself
340 if (this == Thread::current()) {
341 ThreadLocalStorage::set_thread(NULL);
342 } else {
343 // In the case where we're not the current thread, invalidate all the
344 // caches in case some code tries to get the current thread or the
345 // thread that was destroyed, and gets stale information.
346 ThreadLocalStorage::invalidate_all();
347 }
348 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
349 }
351 // NOTE: dummy function for assertion purpose.
352 void Thread::run() {
353 ShouldNotReachHere();
354 }
356 #ifdef ASSERT
357 // Private method to check for dangling thread pointer
358 void check_for_dangling_thread_pointer(Thread *thread) {
359 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
360 "possibility of dangling Thread pointer");
361 }
362 #endif
365 #ifndef PRODUCT
366 // Tracing method for basic thread operations
367 void Thread::trace(const char* msg, const Thread* const thread) {
368 if (!TraceThreadEvents) return;
369 ResourceMark rm;
370 ThreadCritical tc;
371 const char *name = "non-Java thread";
372 int prio = -1;
373 if (thread->is_Java_thread()
374 && !thread->is_Compiler_thread()) {
375 // The Threads_lock must be held to get information about
376 // this thread but may not be in some situations when
377 // tracing thread events.
378 bool release_Threads_lock = false;
379 if (!Threads_lock->owned_by_self()) {
380 Threads_lock->lock();
381 release_Threads_lock = true;
382 }
383 JavaThread* jt = (JavaThread *)thread;
384 name = (char *)jt->get_thread_name();
385 oop thread_oop = jt->threadObj();
386 if (thread_oop != NULL) {
387 prio = java_lang_Thread::priority(thread_oop);
388 }
389 if (release_Threads_lock) {
390 Threads_lock->unlock();
391 }
392 }
393 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
394 }
395 #endif
398 ThreadPriority Thread::get_priority(const Thread* const thread) {
399 trace("get priority", thread);
400 ThreadPriority priority;
401 // Can return an error!
402 (void)os::get_priority(thread, priority);
403 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
404 return priority;
405 }
407 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
408 trace("set priority", thread);
409 debug_only(check_for_dangling_thread_pointer(thread);)
410 // Can return an error!
411 (void)os::set_priority(thread, priority);
412 }
415 void Thread::start(Thread* thread) {
416 trace("start", thread);
417 // Start is different from resume in that its safety is guaranteed by context or
418 // being called from a Java method synchronized on the Thread object.
419 if (!DisableStartThread) {
420 if (thread->is_Java_thread()) {
421 // Initialize the thread state to RUNNABLE before starting this thread.
422 // Can not set it after the thread started because we do not know the
423 // exact thread state at that time. It could be in MONITOR_WAIT or
424 // in SLEEPING or some other state.
425 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
426 java_lang_Thread::RUNNABLE);
427 }
428 os::start_thread(thread);
429 }
430 }
432 // Enqueue a VM_Operation to do the job for us - sometime later
433 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
434 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
435 VMThread::execute(vm_stop);
436 }
439 //
440 // Check if an external suspend request has completed (or has been
441 // cancelled). Returns true if the thread is externally suspended and
442 // false otherwise.
443 //
444 // The bits parameter returns information about the code path through
445 // the routine. Useful for debugging:
446 //
447 // set in is_ext_suspend_completed():
448 // 0x00000001 - routine was entered
449 // 0x00000010 - routine return false at end
450 // 0x00000100 - thread exited (return false)
451 // 0x00000200 - suspend request cancelled (return false)
452 // 0x00000400 - thread suspended (return true)
453 // 0x00001000 - thread is in a suspend equivalent state (return true)
454 // 0x00002000 - thread is native and walkable (return true)
455 // 0x00004000 - thread is native_trans and walkable (needed retry)
456 //
457 // set in wait_for_ext_suspend_completion():
458 // 0x00010000 - routine was entered
459 // 0x00020000 - suspend request cancelled before loop (return false)
460 // 0x00040000 - thread suspended before loop (return true)
461 // 0x00080000 - suspend request cancelled in loop (return false)
462 // 0x00100000 - thread suspended in loop (return true)
463 // 0x00200000 - suspend not completed during retry loop (return false)
464 //
466 // Helper class for tracing suspend wait debug bits.
467 //
468 // 0x00000100 indicates that the target thread exited before it could
469 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
470 // 0x00080000 each indicate a cancelled suspend request so they don't
471 // count as wait failures either.
472 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
474 class TraceSuspendDebugBits : public StackObj {
475 private:
476 JavaThread * jt;
477 bool is_wait;
478 bool called_by_wait; // meaningful when !is_wait
479 uint32_t * bits;
481 public:
482 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
483 uint32_t *_bits) {
484 jt = _jt;
485 is_wait = _is_wait;
486 called_by_wait = _called_by_wait;
487 bits = _bits;
488 }
490 ~TraceSuspendDebugBits() {
491 if (!is_wait) {
492 #if 1
493 // By default, don't trace bits for is_ext_suspend_completed() calls.
494 // That trace is very chatty.
495 return;
496 #else
497 if (!called_by_wait) {
498 // If tracing for is_ext_suspend_completed() is enabled, then only
499 // trace calls to it from wait_for_ext_suspend_completion()
500 return;
501 }
502 #endif
503 }
505 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
506 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
507 MutexLocker ml(Threads_lock); // needed for get_thread_name()
508 ResourceMark rm;
510 tty->print_cr(
511 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
512 jt->get_thread_name(), *bits);
514 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
515 }
516 }
517 }
518 };
519 #undef DEBUG_FALSE_BITS
522 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
523 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
525 bool did_trans_retry = false; // only do thread_in_native_trans retry once
526 bool do_trans_retry; // flag to force the retry
528 *bits |= 0x00000001;
530 do {
531 do_trans_retry = false;
533 if (is_exiting()) {
534 // Thread is in the process of exiting. This is always checked
535 // first to reduce the risk of dereferencing a freed JavaThread.
536 *bits |= 0x00000100;
537 return false;
538 }
540 if (!is_external_suspend()) {
541 // Suspend request is cancelled. This is always checked before
542 // is_ext_suspended() to reduce the risk of a rogue resume
543 // confusing the thread that made the suspend request.
544 *bits |= 0x00000200;
545 return false;
546 }
548 if (is_ext_suspended()) {
549 // thread is suspended
550 *bits |= 0x00000400;
551 return true;
552 }
554 // Now that we no longer do hard suspends of threads running
555 // native code, the target thread can be changing thread state
556 // while we are in this routine:
557 //
558 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
559 //
560 // We save a copy of the thread state as observed at this moment
561 // and make our decision about suspend completeness based on the
562 // copy. This closes the race where the thread state is seen as
563 // _thread_in_native_trans in the if-thread_blocked check, but is
564 // seen as _thread_blocked in if-thread_in_native_trans check.
565 JavaThreadState save_state = thread_state();
567 if (save_state == _thread_blocked && is_suspend_equivalent()) {
568 // If the thread's state is _thread_blocked and this blocking
569 // condition is known to be equivalent to a suspend, then we can
570 // consider the thread to be externally suspended. This means that
571 // the code that sets _thread_blocked has been modified to do
572 // self-suspension if the blocking condition releases. We also
573 // used to check for CONDVAR_WAIT here, but that is now covered by
574 // the _thread_blocked with self-suspension check.
575 //
576 // Return true since we wouldn't be here unless there was still an
577 // external suspend request.
578 *bits |= 0x00001000;
579 return true;
580 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
581 // Threads running native code will self-suspend on native==>VM/Java
582 // transitions. If its stack is walkable (should always be the case
583 // unless this function is called before the actual java_suspend()
584 // call), then the wait is done.
585 *bits |= 0x00002000;
586 return true;
587 } else if (!called_by_wait && !did_trans_retry &&
588 save_state == _thread_in_native_trans &&
589 frame_anchor()->walkable()) {
590 // The thread is transitioning from thread_in_native to another
591 // thread state. check_safepoint_and_suspend_for_native_trans()
592 // will force the thread to self-suspend. If it hasn't gotten
593 // there yet we may have caught the thread in-between the native
594 // code check above and the self-suspend. Lucky us. If we were
595 // called by wait_for_ext_suspend_completion(), then it
596 // will be doing the retries so we don't have to.
597 //
598 // Since we use the saved thread state in the if-statement above,
599 // there is a chance that the thread has already transitioned to
600 // _thread_blocked by the time we get here. In that case, we will
601 // make a single unnecessary pass through the logic below. This
602 // doesn't hurt anything since we still do the trans retry.
604 *bits |= 0x00004000;
606 // Once the thread leaves thread_in_native_trans for another
607 // thread state, we break out of this retry loop. We shouldn't
608 // need this flag to prevent us from getting back here, but
609 // sometimes paranoia is good.
610 did_trans_retry = true;
612 // We wait for the thread to transition to a more usable state.
613 for (int i = 1; i <= SuspendRetryCount; i++) {
614 // We used to do an "os::yield_all(i)" call here with the intention
615 // that yielding would increase on each retry. However, the parameter
616 // is ignored on Linux which means the yield didn't scale up. Waiting
617 // on the SR_lock below provides a much more predictable scale up for
618 // the delay. It also provides a simple/direct point to check for any
619 // safepoint requests from the VMThread
621 // temporarily drops SR_lock while doing wait with safepoint check
622 // (if we're a JavaThread - the WatcherThread can also call this)
623 // and increase delay with each retry
624 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
626 // check the actual thread state instead of what we saved above
627 if (thread_state() != _thread_in_native_trans) {
628 // the thread has transitioned to another thread state so
629 // try all the checks (except this one) one more time.
630 do_trans_retry = true;
631 break;
632 }
633 } // end retry loop
636 }
637 } while (do_trans_retry);
639 *bits |= 0x00000010;
640 return false;
641 }
643 //
644 // Wait for an external suspend request to complete (or be cancelled).
645 // Returns true if the thread is externally suspended and false otherwise.
646 //
647 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
648 uint32_t *bits) {
649 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
650 false /* !called_by_wait */, bits);
652 // local flag copies to minimize SR_lock hold time
653 bool is_suspended;
654 bool pending;
655 uint32_t reset_bits;
657 // set a marker so is_ext_suspend_completed() knows we are the caller
658 *bits |= 0x00010000;
660 // We use reset_bits to reinitialize the bits value at the top of
661 // each retry loop. This allows the caller to make use of any
662 // unused bits for their own marking purposes.
663 reset_bits = *bits;
665 {
666 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
667 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
668 delay, bits);
669 pending = is_external_suspend();
670 }
671 // must release SR_lock to allow suspension to complete
673 if (!pending) {
674 // A cancelled suspend request is the only false return from
675 // is_ext_suspend_completed() that keeps us from entering the
676 // retry loop.
677 *bits |= 0x00020000;
678 return false;
679 }
681 if (is_suspended) {
682 *bits |= 0x00040000;
683 return true;
684 }
686 for (int i = 1; i <= retries; i++) {
687 *bits = reset_bits; // reinit to only track last retry
689 // We used to do an "os::yield_all(i)" call here with the intention
690 // that yielding would increase on each retry. However, the parameter
691 // is ignored on Linux which means the yield didn't scale up. Waiting
692 // on the SR_lock below provides a much more predictable scale up for
693 // the delay. It also provides a simple/direct point to check for any
694 // safepoint requests from the VMThread
696 {
697 MutexLocker ml(SR_lock());
698 // wait with safepoint check (if we're a JavaThread - the WatcherThread
699 // can also call this) and increase delay with each retry
700 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
702 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
703 delay, bits);
705 // It is possible for the external suspend request to be cancelled
706 // (by a resume) before the actual suspend operation is completed.
707 // Refresh our local copy to see if we still need to wait.
708 pending = is_external_suspend();
709 }
711 if (!pending) {
712 // A cancelled suspend request is the only false return from
713 // is_ext_suspend_completed() that keeps us from staying in the
714 // retry loop.
715 *bits |= 0x00080000;
716 return false;
717 }
719 if (is_suspended) {
720 *bits |= 0x00100000;
721 return true;
722 }
723 } // end retry loop
725 // thread did not suspend after all our retries
726 *bits |= 0x00200000;
727 return false;
728 }
730 #ifndef PRODUCT
731 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
733 // This should not need to be atomic as the only way for simultaneous
734 // updates is via interrupts. Even then this should be rare or non-existant
735 // and we don't care that much anyway.
737 int index = _jmp_ring_index;
738 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
739 _jmp_ring[index]._target = (intptr_t) target;
740 _jmp_ring[index]._instruction = (intptr_t) instr;
741 _jmp_ring[index]._file = file;
742 _jmp_ring[index]._line = line;
743 }
744 #endif /* PRODUCT */
746 // Called by flat profiler
747 // Callers have already called wait_for_ext_suspend_completion
748 // The assertion for that is currently too complex to put here:
749 bool JavaThread::profile_last_Java_frame(frame* _fr) {
750 bool gotframe = false;
751 // self suspension saves needed state.
752 if (has_last_Java_frame() && _anchor.walkable()) {
753 *_fr = pd_last_frame();
754 gotframe = true;
755 }
756 return gotframe;
757 }
759 void Thread::interrupt(Thread* thread) {
760 trace("interrupt", thread);
761 debug_only(check_for_dangling_thread_pointer(thread);)
762 os::interrupt(thread);
763 }
765 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
766 trace("is_interrupted", thread);
767 debug_only(check_for_dangling_thread_pointer(thread);)
768 // Note: If clear_interrupted==false, this simply fetches and
769 // returns the value of the field osthread()->interrupted().
770 return os::is_interrupted(thread, clear_interrupted);
771 }
774 // GC Support
775 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
776 jint thread_parity = _oops_do_parity;
777 if (thread_parity != strong_roots_parity) {
778 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
779 if (res == thread_parity) {
780 return true;
781 } else {
782 guarantee(res == strong_roots_parity, "Or else what?");
783 assert(SharedHeap::heap()->workers()->active_workers() > 0,
784 "Should only fail when parallel.");
785 return false;
786 }
787 }
788 assert(SharedHeap::heap()->workers()->active_workers() > 0,
789 "Should only fail when parallel.");
790 return false;
791 }
793 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
794 active_handles()->oops_do(f);
795 // Do oop for ThreadShadow
796 f->do_oop((oop*)&_pending_exception);
797 handle_area()->oops_do(f);
798 }
800 void Thread::nmethods_do(CodeBlobClosure* cf) {
801 // no nmethods in a generic thread...
802 }
804 void Thread::print_on(outputStream* st) const {
805 // get_priority assumes osthread initialized
806 if (osthread() != NULL) {
807 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
808 osthread()->print_on(st);
809 }
810 debug_only(if (WizardMode) print_owned_locks_on(st);)
811 }
813 // Thread::print_on_error() is called by fatal error handler. Don't use
814 // any lock or allocate memory.
815 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
816 if (is_VM_thread()) st->print("VMThread");
817 else if (is_Compiler_thread()) st->print("CompilerThread");
818 else if (is_Java_thread()) st->print("JavaThread");
819 else if (is_GC_task_thread()) st->print("GCTaskThread");
820 else if (is_Watcher_thread()) st->print("WatcherThread");
821 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
822 else st->print("Thread");
824 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
825 _stack_base - _stack_size, _stack_base);
827 if (osthread()) {
828 st->print(" [id=%d]", osthread()->thread_id());
829 }
830 }
832 #ifdef ASSERT
833 void Thread::print_owned_locks_on(outputStream* st) const {
834 Monitor *cur = _owned_locks;
835 if (cur == NULL) {
836 st->print(" (no locks) ");
837 } else {
838 st->print_cr(" Locks owned:");
839 while(cur) {
840 cur->print_on(st);
841 cur = cur->next();
842 }
843 }
844 }
846 static int ref_use_count = 0;
848 bool Thread::owns_locks_but_compiled_lock() const {
849 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
850 if (cur != Compile_lock) return true;
851 }
852 return false;
853 }
856 #endif
858 #ifndef PRODUCT
860 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
861 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
862 // no threads which allow_vm_block's are held
863 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
864 // Check if current thread is allowed to block at a safepoint
865 if (!(_allow_safepoint_count == 0))
866 fatal("Possible safepoint reached by thread that does not allow it");
867 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
868 fatal("LEAF method calling lock?");
869 }
871 #ifdef ASSERT
872 if (potential_vm_operation && is_Java_thread()
873 && !Universe::is_bootstrapping()) {
874 // Make sure we do not hold any locks that the VM thread also uses.
875 // This could potentially lead to deadlocks
876 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
877 // Threads_lock is special, since the safepoint synchronization will not start before this is
878 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
879 // since it is used to transfer control between JavaThreads and the VMThread
880 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
881 if ( (cur->allow_vm_block() &&
882 cur != Threads_lock &&
883 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
884 cur != VMOperationRequest_lock &&
885 cur != VMOperationQueue_lock) ||
886 cur->rank() == Mutex::special) {
887 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
888 }
889 }
890 }
892 if (GCALotAtAllSafepoints) {
893 // We could enter a safepoint here and thus have a gc
894 InterfaceSupport::check_gc_alot();
895 }
896 #endif
897 }
898 #endif
900 bool Thread::is_in_stack(address adr) const {
901 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
902 address end = os::current_stack_pointer();
903 if (stack_base() >= adr && adr >= end) return true;
905 return false;
906 }
909 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
910 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
911 // used for compilation in the future. If that change is made, the need for these methods
912 // should be revisited, and they should be removed if possible.
914 bool Thread::is_lock_owned(address adr) const {
915 return on_local_stack(adr);
916 }
918 bool Thread::set_as_starting_thread() {
919 // NOTE: this must be called inside the main thread.
920 return os::create_main_thread((JavaThread*)this);
921 }
923 static void initialize_class(Symbol* class_name, TRAPS) {
924 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
925 instanceKlass::cast(klass)->initialize(CHECK);
926 }
929 // Creates the initial ThreadGroup
930 static Handle create_initial_thread_group(TRAPS) {
931 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
932 instanceKlassHandle klass (THREAD, k);
934 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
935 {
936 JavaValue result(T_VOID);
937 JavaCalls::call_special(&result,
938 system_instance,
939 klass,
940 vmSymbols::object_initializer_name(),
941 vmSymbols::void_method_signature(),
942 CHECK_NH);
943 }
944 Universe::set_system_thread_group(system_instance());
946 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
947 {
948 JavaValue result(T_VOID);
949 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
950 JavaCalls::call_special(&result,
951 main_instance,
952 klass,
953 vmSymbols::object_initializer_name(),
954 vmSymbols::threadgroup_string_void_signature(),
955 system_instance,
956 string,
957 CHECK_NH);
958 }
959 return main_instance;
960 }
962 // Creates the initial Thread
963 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
964 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
965 instanceKlassHandle klass (THREAD, k);
966 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
968 java_lang_Thread::set_thread(thread_oop(), thread);
969 java_lang_Thread::set_priority(thread_oop(), NormPriority);
970 thread->set_threadObj(thread_oop());
972 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
974 JavaValue result(T_VOID);
975 JavaCalls::call_special(&result, thread_oop,
976 klass,
977 vmSymbols::object_initializer_name(),
978 vmSymbols::threadgroup_string_void_signature(),
979 thread_group,
980 string,
981 CHECK_NULL);
982 return thread_oop();
983 }
985 static void call_initializeSystemClass(TRAPS) {
986 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
987 instanceKlassHandle klass (THREAD, k);
989 JavaValue result(T_VOID);
990 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
991 vmSymbols::void_method_signature(), CHECK);
992 }
994 // General purpose hook into Java code, run once when the VM is initialized.
995 // The Java library method itself may be changed independently from the VM.
996 static void call_postVMInitHook(TRAPS) {
997 klassOop k = SystemDictionary::PostVMInitHook_klass();
998 instanceKlassHandle klass (THREAD, k);
999 if (klass.not_null()) {
1000 JavaValue result(T_VOID);
1001 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1002 vmSymbols::void_method_signature(),
1003 CHECK);
1004 }
1005 }
1007 static void reset_vm_info_property(TRAPS) {
1008 // the vm info string
1009 ResourceMark rm(THREAD);
1010 const char *vm_info = VM_Version::vm_info_string();
1012 // java.lang.System class
1013 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1014 instanceKlassHandle klass (THREAD, k);
1016 // setProperty arguments
1017 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1018 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1020 // return value
1021 JavaValue r(T_OBJECT);
1023 // public static String setProperty(String key, String value);
1024 JavaCalls::call_static(&r,
1025 klass,
1026 vmSymbols::setProperty_name(),
1027 vmSymbols::string_string_string_signature(),
1028 key_str,
1029 value_str,
1030 CHECK);
1031 }
1034 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1035 assert(thread_group.not_null(), "thread group should be specified");
1036 assert(threadObj() == NULL, "should only create Java thread object once");
1038 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1039 instanceKlassHandle klass (THREAD, k);
1040 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1042 java_lang_Thread::set_thread(thread_oop(), this);
1043 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1044 set_threadObj(thread_oop());
1046 JavaValue result(T_VOID);
1047 if (thread_name != NULL) {
1048 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1049 // Thread gets assigned specified name and null target
1050 JavaCalls::call_special(&result,
1051 thread_oop,
1052 klass,
1053 vmSymbols::object_initializer_name(),
1054 vmSymbols::threadgroup_string_void_signature(),
1055 thread_group, // Argument 1
1056 name, // Argument 2
1057 THREAD);
1058 } else {
1059 // Thread gets assigned name "Thread-nnn" and null target
1060 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1061 JavaCalls::call_special(&result,
1062 thread_oop,
1063 klass,
1064 vmSymbols::object_initializer_name(),
1065 vmSymbols::threadgroup_runnable_void_signature(),
1066 thread_group, // Argument 1
1067 Handle(), // Argument 2
1068 THREAD);
1069 }
1072 if (daemon) {
1073 java_lang_Thread::set_daemon(thread_oop());
1074 }
1076 if (HAS_PENDING_EXCEPTION) {
1077 return;
1078 }
1080 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1081 Handle threadObj(this, this->threadObj());
1083 JavaCalls::call_special(&result,
1084 thread_group,
1085 group,
1086 vmSymbols::add_method_name(),
1087 vmSymbols::thread_void_signature(),
1088 threadObj, // Arg 1
1089 THREAD);
1092 }
1094 // NamedThread -- non-JavaThread subclasses with multiple
1095 // uniquely named instances should derive from this.
1096 NamedThread::NamedThread() : Thread() {
1097 _name = NULL;
1098 _processed_thread = NULL;
1099 }
1101 NamedThread::~NamedThread() {
1102 if (_name != NULL) {
1103 FREE_C_HEAP_ARRAY(char, _name);
1104 _name = NULL;
1105 }
1106 }
1108 void NamedThread::set_name(const char* format, ...) {
1109 guarantee(_name == NULL, "Only get to set name once.");
1110 _name = NEW_C_HEAP_ARRAY(char, max_name_len);
1111 guarantee(_name != NULL, "alloc failure");
1112 va_list ap;
1113 va_start(ap, format);
1114 jio_vsnprintf(_name, max_name_len, format, ap);
1115 va_end(ap);
1116 }
1118 // ======= WatcherThread ========
1120 // The watcher thread exists to simulate timer interrupts. It should
1121 // be replaced by an abstraction over whatever native support for
1122 // timer interrupts exists on the platform.
1124 WatcherThread* WatcherThread::_watcher_thread = NULL;
1125 volatile bool WatcherThread::_should_terminate = false;
1127 WatcherThread::WatcherThread() : Thread() {
1128 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1129 if (os::create_thread(this, os::watcher_thread)) {
1130 _watcher_thread = this;
1132 // Set the watcher thread to the highest OS priority which should not be
1133 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1134 // is created. The only normal thread using this priority is the reference
1135 // handler thread, which runs for very short intervals only.
1136 // If the VMThread's priority is not lower than the WatcherThread profiling
1137 // will be inaccurate.
1138 os::set_priority(this, MaxPriority);
1139 if (!DisableStartThread) {
1140 os::start_thread(this);
1141 }
1142 }
1143 }
1145 void WatcherThread::run() {
1146 assert(this == watcher_thread(), "just checking");
1148 this->record_stack_base_and_size();
1149 this->initialize_thread_local_storage();
1150 this->set_active_handles(JNIHandleBlock::allocate_block());
1151 while(!_should_terminate) {
1152 assert(watcher_thread() == Thread::current(), "thread consistency check");
1153 assert(watcher_thread() == this, "thread consistency check");
1155 // Calculate how long it'll be until the next PeriodicTask work
1156 // should be done, and sleep that amount of time.
1157 size_t time_to_wait = PeriodicTask::time_to_wait();
1159 // we expect this to timeout - we only ever get unparked when
1160 // we should terminate
1161 {
1162 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1164 jlong prev_time = os::javaTimeNanos();
1165 for (;;) {
1166 int res= _SleepEvent->park(time_to_wait);
1167 if (res == OS_TIMEOUT || _should_terminate)
1168 break;
1169 // spurious wakeup of some kind
1170 jlong now = os::javaTimeNanos();
1171 time_to_wait -= (now - prev_time) / 1000000;
1172 if (time_to_wait <= 0)
1173 break;
1174 prev_time = now;
1175 }
1176 }
1178 if (is_error_reported()) {
1179 // A fatal error has happened, the error handler(VMError::report_and_die)
1180 // should abort JVM after creating an error log file. However in some
1181 // rare cases, the error handler itself might deadlock. Here we try to
1182 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1183 //
1184 // This code is in WatcherThread because WatcherThread wakes up
1185 // periodically so the fatal error handler doesn't need to do anything;
1186 // also because the WatcherThread is less likely to crash than other
1187 // threads.
1189 for (;;) {
1190 if (!ShowMessageBoxOnError
1191 && (OnError == NULL || OnError[0] == '\0')
1192 && Arguments::abort_hook() == NULL) {
1193 os::sleep(this, 2 * 60 * 1000, false);
1194 fdStream err(defaultStream::output_fd());
1195 err.print_raw_cr("# [ timer expired, abort... ]");
1196 // skip atexit/vm_exit/vm_abort hooks
1197 os::die();
1198 }
1200 // Wake up 5 seconds later, the fatal handler may reset OnError or
1201 // ShowMessageBoxOnError when it is ready to abort.
1202 os::sleep(this, 5 * 1000, false);
1203 }
1204 }
1206 PeriodicTask::real_time_tick(time_to_wait);
1208 // If we have no more tasks left due to dynamic disenrollment,
1209 // shut down the thread since we don't currently support dynamic enrollment
1210 if (PeriodicTask::num_tasks() == 0) {
1211 _should_terminate = true;
1212 }
1213 }
1215 // Signal that it is terminated
1216 {
1217 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1218 _watcher_thread = NULL;
1219 Terminator_lock->notify();
1220 }
1222 // Thread destructor usually does this..
1223 ThreadLocalStorage::set_thread(NULL);
1224 }
1226 void WatcherThread::start() {
1227 if (watcher_thread() == NULL) {
1228 _should_terminate = false;
1229 // Create the single instance of WatcherThread
1230 new WatcherThread();
1231 }
1232 }
1234 void WatcherThread::stop() {
1235 // it is ok to take late safepoints here, if needed
1236 MutexLocker mu(Terminator_lock);
1237 _should_terminate = true;
1238 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1240 Thread* watcher = watcher_thread();
1241 if (watcher != NULL)
1242 watcher->_SleepEvent->unpark();
1244 while(watcher_thread() != NULL) {
1245 // This wait should make safepoint checks, wait without a timeout,
1246 // and wait as a suspend-equivalent condition.
1247 //
1248 // Note: If the FlatProfiler is running, then this thread is waiting
1249 // for the WatcherThread to terminate and the WatcherThread, via the
1250 // FlatProfiler task, is waiting for the external suspend request on
1251 // this thread to complete. wait_for_ext_suspend_completion() will
1252 // eventually timeout, but that takes time. Making this wait a
1253 // suspend-equivalent condition solves that timeout problem.
1254 //
1255 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1256 Mutex::_as_suspend_equivalent_flag);
1257 }
1258 }
1260 void WatcherThread::print_on(outputStream* st) const {
1261 st->print("\"%s\" ", name());
1262 Thread::print_on(st);
1263 st->cr();
1264 }
1266 // ======= JavaThread ========
1268 // A JavaThread is a normal Java thread
1270 void JavaThread::initialize() {
1271 // Initialize fields
1273 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1274 set_claimed_par_id(-1);
1276 set_saved_exception_pc(NULL);
1277 set_threadObj(NULL);
1278 _anchor.clear();
1279 set_entry_point(NULL);
1280 set_jni_functions(jni_functions());
1281 set_callee_target(NULL);
1282 set_vm_result(NULL);
1283 set_vm_result_2(NULL);
1284 set_vframe_array_head(NULL);
1285 set_vframe_array_last(NULL);
1286 set_deferred_locals(NULL);
1287 set_deopt_mark(NULL);
1288 set_deopt_nmethod(NULL);
1289 clear_must_deopt_id();
1290 set_monitor_chunks(NULL);
1291 set_next(NULL);
1292 set_thread_state(_thread_new);
1293 _terminated = _not_terminated;
1294 _privileged_stack_top = NULL;
1295 _array_for_gc = NULL;
1296 _suspend_equivalent = false;
1297 _in_deopt_handler = 0;
1298 _doing_unsafe_access = false;
1299 _stack_guard_state = stack_guard_unused;
1300 _exception_oop = NULL;
1301 _exception_pc = 0;
1302 _exception_handler_pc = 0;
1303 _is_method_handle_return = 0;
1304 _jvmti_thread_state= NULL;
1305 _should_post_on_exceptions_flag = JNI_FALSE;
1306 _jvmti_get_loaded_classes_closure = NULL;
1307 _interp_only_mode = 0;
1308 _special_runtime_exit_condition = _no_async_condition;
1309 _pending_async_exception = NULL;
1310 _is_compiling = false;
1311 _thread_stat = NULL;
1312 _thread_stat = new ThreadStatistics();
1313 _blocked_on_compilation = false;
1314 _jni_active_critical = 0;
1315 _do_not_unlock_if_synchronized = false;
1316 _cached_monitor_info = NULL;
1317 _parker = Parker::Allocate(this) ;
1319 #ifndef PRODUCT
1320 _jmp_ring_index = 0;
1321 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1322 record_jump(NULL, NULL, NULL, 0);
1323 }
1324 #endif /* PRODUCT */
1326 set_thread_profiler(NULL);
1327 if (FlatProfiler::is_active()) {
1328 // This is where we would decide to either give each thread it's own profiler
1329 // or use one global one from FlatProfiler,
1330 // or up to some count of the number of profiled threads, etc.
1331 ThreadProfiler* pp = new ThreadProfiler();
1332 pp->engage();
1333 set_thread_profiler(pp);
1334 }
1336 // Setup safepoint state info for this thread
1337 ThreadSafepointState::create(this);
1339 debug_only(_java_call_counter = 0);
1341 // JVMTI PopFrame support
1342 _popframe_condition = popframe_inactive;
1343 _popframe_preserved_args = NULL;
1344 _popframe_preserved_args_size = 0;
1346 pd_initialize();
1347 }
1349 #ifndef SERIALGC
1350 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1351 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1352 #endif // !SERIALGC
1354 JavaThread::JavaThread(bool is_attaching_via_jni) :
1355 Thread()
1356 #ifndef SERIALGC
1357 , _satb_mark_queue(&_satb_mark_queue_set),
1358 _dirty_card_queue(&_dirty_card_queue_set)
1359 #endif // !SERIALGC
1360 {
1361 initialize();
1362 if (is_attaching_via_jni) {
1363 _jni_attach_state = _attaching_via_jni;
1364 } else {
1365 _jni_attach_state = _not_attaching_via_jni;
1366 }
1367 assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor");
1368 }
1370 bool JavaThread::reguard_stack(address cur_sp) {
1371 if (_stack_guard_state != stack_guard_yellow_disabled) {
1372 return true; // Stack already guarded or guard pages not needed.
1373 }
1375 if (register_stack_overflow()) {
1376 // For those architectures which have separate register and
1377 // memory stacks, we must check the register stack to see if
1378 // it has overflowed.
1379 return false;
1380 }
1382 // Java code never executes within the yellow zone: the latter is only
1383 // there to provoke an exception during stack banging. If java code
1384 // is executing there, either StackShadowPages should be larger, or
1385 // some exception code in c1, c2 or the interpreter isn't unwinding
1386 // when it should.
1387 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1389 enable_stack_yellow_zone();
1390 return true;
1391 }
1393 bool JavaThread::reguard_stack(void) {
1394 return reguard_stack(os::current_stack_pointer());
1395 }
1398 void JavaThread::block_if_vm_exited() {
1399 if (_terminated == _vm_exited) {
1400 // _vm_exited is set at safepoint, and Threads_lock is never released
1401 // we will block here forever
1402 Threads_lock->lock_without_safepoint_check();
1403 ShouldNotReachHere();
1404 }
1405 }
1408 // Remove this ifdef when C1 is ported to the compiler interface.
1409 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1411 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1412 Thread()
1413 #ifndef SERIALGC
1414 , _satb_mark_queue(&_satb_mark_queue_set),
1415 _dirty_card_queue(&_dirty_card_queue_set)
1416 #endif // !SERIALGC
1417 {
1418 if (TraceThreadEvents) {
1419 tty->print_cr("creating thread %p", this);
1420 }
1421 initialize();
1422 _jni_attach_state = _not_attaching_via_jni;
1423 set_entry_point(entry_point);
1424 // Create the native thread itself.
1425 // %note runtime_23
1426 os::ThreadType thr_type = os::java_thread;
1427 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1428 os::java_thread;
1429 os::create_thread(this, thr_type, stack_sz);
1431 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1432 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1433 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1434 // the exception consists of creating the exception object & initializing it, initialization
1435 // will leave the VM via a JavaCall and then all locks must be unlocked).
1436 //
1437 // The thread is still suspended when we reach here. Thread must be explicit started
1438 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1439 // by calling Threads:add. The reason why this is not done here, is because the thread
1440 // object must be fully initialized (take a look at JVM_Start)
1441 }
1443 JavaThread::~JavaThread() {
1444 if (TraceThreadEvents) {
1445 tty->print_cr("terminate thread %p", this);
1446 }
1448 // JSR166 -- return the parker to the free list
1449 Parker::Release(_parker);
1450 _parker = NULL ;
1452 // Free any remaining previous UnrollBlock
1453 vframeArray* old_array = vframe_array_last();
1455 if (old_array != NULL) {
1456 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1457 old_array->set_unroll_block(NULL);
1458 delete old_info;
1459 delete old_array;
1460 }
1462 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1463 if (deferred != NULL) {
1464 // This can only happen if thread is destroyed before deoptimization occurs.
1465 assert(deferred->length() != 0, "empty array!");
1466 do {
1467 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1468 deferred->remove_at(0);
1469 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1470 delete dlv;
1471 } while (deferred->length() != 0);
1472 delete deferred;
1473 }
1475 // All Java related clean up happens in exit
1476 ThreadSafepointState::destroy(this);
1477 if (_thread_profiler != NULL) delete _thread_profiler;
1478 if (_thread_stat != NULL) delete _thread_stat;
1479 }
1482 // The first routine called by a new Java thread
1483 void JavaThread::run() {
1484 // initialize thread-local alloc buffer related fields
1485 this->initialize_tlab();
1487 // used to test validitity of stack trace backs
1488 this->record_base_of_stack_pointer();
1490 // Record real stack base and size.
1491 this->record_stack_base_and_size();
1493 // Initialize thread local storage; set before calling MutexLocker
1494 this->initialize_thread_local_storage();
1496 this->create_stack_guard_pages();
1498 this->cache_global_variables();
1500 // Thread is now sufficient initialized to be handled by the safepoint code as being
1501 // in the VM. Change thread state from _thread_new to _thread_in_vm
1502 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1504 assert(JavaThread::current() == this, "sanity check");
1505 assert(!Thread::current()->owns_locks(), "sanity check");
1507 DTRACE_THREAD_PROBE(start, this);
1509 // This operation might block. We call that after all safepoint checks for a new thread has
1510 // been completed.
1511 this->set_active_handles(JNIHandleBlock::allocate_block());
1513 if (JvmtiExport::should_post_thread_life()) {
1514 JvmtiExport::post_thread_start(this);
1515 }
1517 EVENT_BEGIN(TraceEventThreadStart, event);
1518 EVENT_COMMIT(event,
1519 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj())));
1521 // We call another function to do the rest so we are sure that the stack addresses used
1522 // from there will be lower than the stack base just computed
1523 thread_main_inner();
1525 // Note, thread is no longer valid at this point!
1526 }
1529 void JavaThread::thread_main_inner() {
1530 assert(JavaThread::current() == this, "sanity check");
1531 assert(this->threadObj() != NULL, "just checking");
1533 // Execute thread entry point unless this thread has a pending exception
1534 // or has been stopped before starting.
1535 // Note: Due to JVM_StopThread we can have pending exceptions already!
1536 if (!this->has_pending_exception() &&
1537 !java_lang_Thread::is_stillborn(this->threadObj())) {
1538 {
1539 ResourceMark rm(this);
1540 this->set_native_thread_name(this->get_thread_name());
1541 }
1542 HandleMark hm(this);
1543 this->entry_point()(this, this);
1544 }
1546 DTRACE_THREAD_PROBE(stop, this);
1548 this->exit(false);
1549 delete this;
1550 }
1553 static void ensure_join(JavaThread* thread) {
1554 // We do not need to grap the Threads_lock, since we are operating on ourself.
1555 Handle threadObj(thread, thread->threadObj());
1556 assert(threadObj.not_null(), "java thread object must exist");
1557 ObjectLocker lock(threadObj, thread);
1558 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1559 thread->clear_pending_exception();
1560 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1561 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1562 // Clear the native thread instance - this makes isAlive return false and allows the join()
1563 // to complete once we've done the notify_all below
1564 java_lang_Thread::set_thread(threadObj(), NULL);
1565 lock.notify_all(thread);
1566 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1567 thread->clear_pending_exception();
1568 }
1571 // For any new cleanup additions, please check to see if they need to be applied to
1572 // cleanup_failed_attach_current_thread as well.
1573 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1574 assert(this == JavaThread::current(), "thread consistency check");
1575 if (!InitializeJavaLangSystem) return;
1577 HandleMark hm(this);
1578 Handle uncaught_exception(this, this->pending_exception());
1579 this->clear_pending_exception();
1580 Handle threadObj(this, this->threadObj());
1581 assert(threadObj.not_null(), "Java thread object should be created");
1583 if (get_thread_profiler() != NULL) {
1584 get_thread_profiler()->disengage();
1585 ResourceMark rm;
1586 get_thread_profiler()->print(get_thread_name());
1587 }
1590 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1591 {
1592 EXCEPTION_MARK;
1594 CLEAR_PENDING_EXCEPTION;
1595 }
1596 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1597 // has to be fixed by a runtime query method
1598 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1599 // JSR-166: change call from from ThreadGroup.uncaughtException to
1600 // java.lang.Thread.dispatchUncaughtException
1601 if (uncaught_exception.not_null()) {
1602 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1603 Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT",
1604 (address)uncaught_exception(), (address)threadObj(), (address)group());
1605 {
1606 EXCEPTION_MARK;
1607 // Check if the method Thread.dispatchUncaughtException() exists. If so
1608 // call it. Otherwise we have an older library without the JSR-166 changes,
1609 // so call ThreadGroup.uncaughtException()
1610 KlassHandle recvrKlass(THREAD, threadObj->klass());
1611 CallInfo callinfo;
1612 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1613 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1614 vmSymbols::dispatchUncaughtException_name(),
1615 vmSymbols::throwable_void_signature(),
1616 KlassHandle(), false, false, THREAD);
1617 CLEAR_PENDING_EXCEPTION;
1618 methodHandle method = callinfo.selected_method();
1619 if (method.not_null()) {
1620 JavaValue result(T_VOID);
1621 JavaCalls::call_virtual(&result,
1622 threadObj, thread_klass,
1623 vmSymbols::dispatchUncaughtException_name(),
1624 vmSymbols::throwable_void_signature(),
1625 uncaught_exception,
1626 THREAD);
1627 } else {
1628 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1629 JavaValue result(T_VOID);
1630 JavaCalls::call_virtual(&result,
1631 group, thread_group,
1632 vmSymbols::uncaughtException_name(),
1633 vmSymbols::thread_throwable_void_signature(),
1634 threadObj, // Arg 1
1635 uncaught_exception, // Arg 2
1636 THREAD);
1637 }
1638 if (HAS_PENDING_EXCEPTION) {
1639 ResourceMark rm(this);
1640 jio_fprintf(defaultStream::error_stream(),
1641 "\nException: %s thrown from the UncaughtExceptionHandler"
1642 " in thread \"%s\"\n",
1643 Klass::cast(pending_exception()->klass())->external_name(),
1644 get_thread_name());
1645 CLEAR_PENDING_EXCEPTION;
1646 }
1647 }
1648 }
1650 // Called before the java thread exit since we want to read info
1651 // from java_lang_Thread object
1652 EVENT_BEGIN(TraceEventThreadEnd, event);
1653 EVENT_COMMIT(event,
1654 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj())));
1656 // Call after last event on thread
1657 EVENT_THREAD_EXIT(this);
1659 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1660 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1661 // is deprecated anyhow.
1662 { int count = 3;
1663 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1664 EXCEPTION_MARK;
1665 JavaValue result(T_VOID);
1666 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1667 JavaCalls::call_virtual(&result,
1668 threadObj, thread_klass,
1669 vmSymbols::exit_method_name(),
1670 vmSymbols::void_method_signature(),
1671 THREAD);
1672 CLEAR_PENDING_EXCEPTION;
1673 }
1674 }
1676 // notify JVMTI
1677 if (JvmtiExport::should_post_thread_life()) {
1678 JvmtiExport::post_thread_end(this);
1679 }
1681 // We have notified the agents that we are exiting, before we go on,
1682 // we must check for a pending external suspend request and honor it
1683 // in order to not surprise the thread that made the suspend request.
1684 while (true) {
1685 {
1686 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1687 if (!is_external_suspend()) {
1688 set_terminated(_thread_exiting);
1689 ThreadService::current_thread_exiting(this);
1690 break;
1691 }
1692 // Implied else:
1693 // Things get a little tricky here. We have a pending external
1694 // suspend request, but we are holding the SR_lock so we
1695 // can't just self-suspend. So we temporarily drop the lock
1696 // and then self-suspend.
1697 }
1699 ThreadBlockInVM tbivm(this);
1700 java_suspend_self();
1702 // We're done with this suspend request, but we have to loop around
1703 // and check again. Eventually we will get SR_lock without a pending
1704 // external suspend request and will be able to mark ourselves as
1705 // exiting.
1706 }
1707 // no more external suspends are allowed at this point
1708 } else {
1709 // before_exit() has already posted JVMTI THREAD_END events
1710 }
1712 // Notify waiters on thread object. This has to be done after exit() is called
1713 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1714 // group should have the destroyed bit set before waiters are notified).
1715 ensure_join(this);
1716 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1718 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1719 // held by this thread must be released. A detach operation must only
1720 // get here if there are no Java frames on the stack. Therefore, any
1721 // owned monitors at this point MUST be JNI-acquired monitors which are
1722 // pre-inflated and in the monitor cache.
1723 //
1724 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1725 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1726 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1727 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1728 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1729 }
1731 // These things needs to be done while we are still a Java Thread. Make sure that thread
1732 // is in a consistent state, in case GC happens
1733 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1735 if (active_handles() != NULL) {
1736 JNIHandleBlock* block = active_handles();
1737 set_active_handles(NULL);
1738 JNIHandleBlock::release_block(block);
1739 }
1741 if (free_handle_block() != NULL) {
1742 JNIHandleBlock* block = free_handle_block();
1743 set_free_handle_block(NULL);
1744 JNIHandleBlock::release_block(block);
1745 }
1747 // These have to be removed while this is still a valid thread.
1748 remove_stack_guard_pages();
1750 if (UseTLAB) {
1751 tlab().make_parsable(true); // retire TLAB
1752 }
1754 if (JvmtiEnv::environments_might_exist()) {
1755 JvmtiExport::cleanup_thread(this);
1756 }
1758 #ifndef SERIALGC
1759 // We must flush G1-related buffers before removing a thread from
1760 // the list of active threads.
1761 if (UseG1GC) {
1762 flush_barrier_queues();
1763 }
1764 #endif
1766 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1767 Threads::remove(this);
1768 }
1770 #ifndef SERIALGC
1771 // Flush G1-related queues.
1772 void JavaThread::flush_barrier_queues() {
1773 satb_mark_queue().flush();
1774 dirty_card_queue().flush();
1775 }
1777 void JavaThread::initialize_queues() {
1778 assert(!SafepointSynchronize::is_at_safepoint(),
1779 "we should not be at a safepoint");
1781 ObjPtrQueue& satb_queue = satb_mark_queue();
1782 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1783 // The SATB queue should have been constructed with its active
1784 // field set to false.
1785 assert(!satb_queue.is_active(), "SATB queue should not be active");
1786 assert(satb_queue.is_empty(), "SATB queue should be empty");
1787 // If we are creating the thread during a marking cycle, we should
1788 // set the active field of the SATB queue to true.
1789 if (satb_queue_set.is_active()) {
1790 satb_queue.set_active(true);
1791 }
1793 DirtyCardQueue& dirty_queue = dirty_card_queue();
1794 // The dirty card queue should have been constructed with its
1795 // active field set to true.
1796 assert(dirty_queue.is_active(), "dirty card queue should be active");
1797 }
1798 #endif // !SERIALGC
1800 void JavaThread::cleanup_failed_attach_current_thread() {
1801 if (get_thread_profiler() != NULL) {
1802 get_thread_profiler()->disengage();
1803 ResourceMark rm;
1804 get_thread_profiler()->print(get_thread_name());
1805 }
1807 if (active_handles() != NULL) {
1808 JNIHandleBlock* block = active_handles();
1809 set_active_handles(NULL);
1810 JNIHandleBlock::release_block(block);
1811 }
1813 if (free_handle_block() != NULL) {
1814 JNIHandleBlock* block = free_handle_block();
1815 set_free_handle_block(NULL);
1816 JNIHandleBlock::release_block(block);
1817 }
1819 // These have to be removed while this is still a valid thread.
1820 remove_stack_guard_pages();
1822 if (UseTLAB) {
1823 tlab().make_parsable(true); // retire TLAB, if any
1824 }
1826 #ifndef SERIALGC
1827 if (UseG1GC) {
1828 flush_barrier_queues();
1829 }
1830 #endif
1832 Threads::remove(this);
1833 delete this;
1834 }
1839 JavaThread* JavaThread::active() {
1840 Thread* thread = ThreadLocalStorage::thread();
1841 assert(thread != NULL, "just checking");
1842 if (thread->is_Java_thread()) {
1843 return (JavaThread*) thread;
1844 } else {
1845 assert(thread->is_VM_thread(), "this must be a vm thread");
1846 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1847 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1848 assert(ret->is_Java_thread(), "must be a Java thread");
1849 return ret;
1850 }
1851 }
1853 bool JavaThread::is_lock_owned(address adr) const {
1854 if (Thread::is_lock_owned(adr)) return true;
1856 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1857 if (chunk->contains(adr)) return true;
1858 }
1860 return false;
1861 }
1864 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1865 chunk->set_next(monitor_chunks());
1866 set_monitor_chunks(chunk);
1867 }
1869 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1870 guarantee(monitor_chunks() != NULL, "must be non empty");
1871 if (monitor_chunks() == chunk) {
1872 set_monitor_chunks(chunk->next());
1873 } else {
1874 MonitorChunk* prev = monitor_chunks();
1875 while (prev->next() != chunk) prev = prev->next();
1876 prev->set_next(chunk->next());
1877 }
1878 }
1880 // JVM support.
1882 // Note: this function shouldn't block if it's called in
1883 // _thread_in_native_trans state (such as from
1884 // check_special_condition_for_native_trans()).
1885 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1887 if (has_last_Java_frame() && has_async_condition()) {
1888 // If we are at a polling page safepoint (not a poll return)
1889 // then we must defer async exception because live registers
1890 // will be clobbered by the exception path. Poll return is
1891 // ok because the call we a returning from already collides
1892 // with exception handling registers and so there is no issue.
1893 // (The exception handling path kills call result registers but
1894 // this is ok since the exception kills the result anyway).
1896 if (is_at_poll_safepoint()) {
1897 // if the code we are returning to has deoptimized we must defer
1898 // the exception otherwise live registers get clobbered on the
1899 // exception path before deoptimization is able to retrieve them.
1900 //
1901 RegisterMap map(this, false);
1902 frame caller_fr = last_frame().sender(&map);
1903 assert(caller_fr.is_compiled_frame(), "what?");
1904 if (caller_fr.is_deoptimized_frame()) {
1905 if (TraceExceptions) {
1906 ResourceMark rm;
1907 tty->print_cr("deferred async exception at compiled safepoint");
1908 }
1909 return;
1910 }
1911 }
1912 }
1914 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
1915 if (condition == _no_async_condition) {
1916 // Conditions have changed since has_special_runtime_exit_condition()
1917 // was called:
1918 // - if we were here only because of an external suspend request,
1919 // then that was taken care of above (or cancelled) so we are done
1920 // - if we were here because of another async request, then it has
1921 // been cleared between the has_special_runtime_exit_condition()
1922 // and now so again we are done
1923 return;
1924 }
1926 // Check for pending async. exception
1927 if (_pending_async_exception != NULL) {
1928 // Only overwrite an already pending exception, if it is not a threadDeath.
1929 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
1931 // We cannot call Exceptions::_throw(...) here because we cannot block
1932 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1934 if (TraceExceptions) {
1935 ResourceMark rm;
1936 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
1937 if (has_last_Java_frame() ) {
1938 frame f = last_frame();
1939 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
1940 }
1941 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1942 }
1943 _pending_async_exception = NULL;
1944 clear_has_async_exception();
1945 }
1946 }
1948 if (check_unsafe_error &&
1949 condition == _async_unsafe_access_error && !has_pending_exception()) {
1950 condition = _no_async_condition; // done
1951 switch (thread_state()) {
1952 case _thread_in_vm:
1953 {
1954 JavaThread* THREAD = this;
1955 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1956 }
1957 case _thread_in_native:
1958 {
1959 ThreadInVMfromNative tiv(this);
1960 JavaThread* THREAD = this;
1961 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1962 }
1963 case _thread_in_Java:
1964 {
1965 ThreadInVMfromJava tiv(this);
1966 JavaThread* THREAD = this;
1967 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
1968 }
1969 default:
1970 ShouldNotReachHere();
1971 }
1972 }
1974 assert(condition == _no_async_condition || has_pending_exception() ||
1975 (!check_unsafe_error && condition == _async_unsafe_access_error),
1976 "must have handled the async condition, if no exception");
1977 }
1979 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1980 //
1981 // Check for pending external suspend. Internal suspend requests do
1982 // not use handle_special_runtime_exit_condition().
1983 // If JNIEnv proxies are allowed, don't self-suspend if the target
1984 // thread is not the current thread. In older versions of jdbx, jdbx
1985 // threads could call into the VM with another thread's JNIEnv so we
1986 // can be here operating on behalf of a suspended thread (4432884).
1987 bool do_self_suspend = is_external_suspend_with_lock();
1988 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
1989 //
1990 // Because thread is external suspended the safepoint code will count
1991 // thread as at a safepoint. This can be odd because we can be here
1992 // as _thread_in_Java which would normally transition to _thread_blocked
1993 // at a safepoint. We would like to mark the thread as _thread_blocked
1994 // before calling java_suspend_self like all other callers of it but
1995 // we must then observe proper safepoint protocol. (We can't leave
1996 // _thread_blocked with a safepoint in progress). However we can be
1997 // here as _thread_in_native_trans so we can't use a normal transition
1998 // constructor/destructor pair because they assert on that type of
1999 // transition. We could do something like:
2000 //
2001 // JavaThreadState state = thread_state();
2002 // set_thread_state(_thread_in_vm);
2003 // {
2004 // ThreadBlockInVM tbivm(this);
2005 // java_suspend_self()
2006 // }
2007 // set_thread_state(_thread_in_vm_trans);
2008 // if (safepoint) block;
2009 // set_thread_state(state);
2010 //
2011 // but that is pretty messy. Instead we just go with the way the
2012 // code has worked before and note that this is the only path to
2013 // java_suspend_self that doesn't put the thread in _thread_blocked
2014 // mode.
2016 frame_anchor()->make_walkable(this);
2017 java_suspend_self();
2019 // We might be here for reasons in addition to the self-suspend request
2020 // so check for other async requests.
2021 }
2023 if (check_asyncs) {
2024 check_and_handle_async_exceptions();
2025 }
2026 }
2028 void JavaThread::send_thread_stop(oop java_throwable) {
2029 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2030 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2031 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2033 // Do not throw asynchronous exceptions against the compiler thread
2034 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2035 if (is_Compiler_thread()) return;
2037 {
2038 // Actually throw the Throwable against the target Thread - however
2039 // only if there is no thread death exception installed already.
2040 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2041 // If the topmost frame is a runtime stub, then we are calling into
2042 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2043 // must deoptimize the caller before continuing, as the compiled exception handler table
2044 // may not be valid
2045 if (has_last_Java_frame()) {
2046 frame f = last_frame();
2047 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2048 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2049 RegisterMap reg_map(this, UseBiasedLocking);
2050 frame compiled_frame = f.sender(®_map);
2051 if (compiled_frame.can_be_deoptimized()) {
2052 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2053 }
2054 }
2055 }
2057 // Set async. pending exception in thread.
2058 set_pending_async_exception(java_throwable);
2060 if (TraceExceptions) {
2061 ResourceMark rm;
2062 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
2063 }
2064 // for AbortVMOnException flag
2065 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
2066 }
2067 }
2070 // Interrupt thread so it will wake up from a potential wait()
2071 Thread::interrupt(this);
2072 }
2074 // External suspension mechanism.
2075 //
2076 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2077 // to any VM_locks and it is at a transition
2078 // Self-suspension will happen on the transition out of the vm.
2079 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2080 //
2081 // Guarantees on return:
2082 // + Target thread will not execute any new bytecode (that's why we need to
2083 // force a safepoint)
2084 // + Target thread will not enter any new monitors
2085 //
2086 void JavaThread::java_suspend() {
2087 { MutexLocker mu(Threads_lock);
2088 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2089 return;
2090 }
2091 }
2093 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2094 if (!is_external_suspend()) {
2095 // a racing resume has cancelled us; bail out now
2096 return;
2097 }
2099 // suspend is done
2100 uint32_t debug_bits = 0;
2101 // Warning: is_ext_suspend_completed() may temporarily drop the
2102 // SR_lock to allow the thread to reach a stable thread state if
2103 // it is currently in a transient thread state.
2104 if (is_ext_suspend_completed(false /* !called_by_wait */,
2105 SuspendRetryDelay, &debug_bits) ) {
2106 return;
2107 }
2108 }
2110 VM_ForceSafepoint vm_suspend;
2111 VMThread::execute(&vm_suspend);
2112 }
2114 // Part II of external suspension.
2115 // A JavaThread self suspends when it detects a pending external suspend
2116 // request. This is usually on transitions. It is also done in places
2117 // where continuing to the next transition would surprise the caller,
2118 // e.g., monitor entry.
2119 //
2120 // Returns the number of times that the thread self-suspended.
2121 //
2122 // Note: DO NOT call java_suspend_self() when you just want to block current
2123 // thread. java_suspend_self() is the second stage of cooperative
2124 // suspension for external suspend requests and should only be used
2125 // to complete an external suspend request.
2126 //
2127 int JavaThread::java_suspend_self() {
2128 int ret = 0;
2130 // we are in the process of exiting so don't suspend
2131 if (is_exiting()) {
2132 clear_external_suspend();
2133 return ret;
2134 }
2136 assert(_anchor.walkable() ||
2137 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2138 "must have walkable stack");
2140 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2142 assert(!this->is_ext_suspended(),
2143 "a thread trying to self-suspend should not already be suspended");
2145 if (this->is_suspend_equivalent()) {
2146 // If we are self-suspending as a result of the lifting of a
2147 // suspend equivalent condition, then the suspend_equivalent
2148 // flag is not cleared until we set the ext_suspended flag so
2149 // that wait_for_ext_suspend_completion() returns consistent
2150 // results.
2151 this->clear_suspend_equivalent();
2152 }
2154 // A racing resume may have cancelled us before we grabbed SR_lock
2155 // above. Or another external suspend request could be waiting for us
2156 // by the time we return from SR_lock()->wait(). The thread
2157 // that requested the suspension may already be trying to walk our
2158 // stack and if we return now, we can change the stack out from under
2159 // it. This would be a "bad thing (TM)" and cause the stack walker
2160 // to crash. We stay self-suspended until there are no more pending
2161 // external suspend requests.
2162 while (is_external_suspend()) {
2163 ret++;
2164 this->set_ext_suspended();
2166 // _ext_suspended flag is cleared by java_resume()
2167 while (is_ext_suspended()) {
2168 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2169 }
2170 }
2172 return ret;
2173 }
2175 #ifdef ASSERT
2176 // verify the JavaThread has not yet been published in the Threads::list, and
2177 // hence doesn't need protection from concurrent access at this stage
2178 void JavaThread::verify_not_published() {
2179 if (!Threads_lock->owned_by_self()) {
2180 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2181 assert( !Threads::includes(this),
2182 "java thread shouldn't have been published yet!");
2183 }
2184 else {
2185 assert( !Threads::includes(this),
2186 "java thread shouldn't have been published yet!");
2187 }
2188 }
2189 #endif
2191 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2192 // progress or when _suspend_flags is non-zero.
2193 // Current thread needs to self-suspend if there is a suspend request and/or
2194 // block if a safepoint is in progress.
2195 // Async exception ISN'T checked.
2196 // Note only the ThreadInVMfromNative transition can call this function
2197 // directly and when thread state is _thread_in_native_trans
2198 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2199 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2201 JavaThread *curJT = JavaThread::current();
2202 bool do_self_suspend = thread->is_external_suspend();
2204 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2206 // If JNIEnv proxies are allowed, don't self-suspend if the target
2207 // thread is not the current thread. In older versions of jdbx, jdbx
2208 // threads could call into the VM with another thread's JNIEnv so we
2209 // can be here operating on behalf of a suspended thread (4432884).
2210 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2211 JavaThreadState state = thread->thread_state();
2213 // We mark this thread_blocked state as a suspend-equivalent so
2214 // that a caller to is_ext_suspend_completed() won't be confused.
2215 // The suspend-equivalent state is cleared by java_suspend_self().
2216 thread->set_suspend_equivalent();
2218 // If the safepoint code sees the _thread_in_native_trans state, it will
2219 // wait until the thread changes to other thread state. There is no
2220 // guarantee on how soon we can obtain the SR_lock and complete the
2221 // self-suspend request. It would be a bad idea to let safepoint wait for
2222 // too long. Temporarily change the state to _thread_blocked to
2223 // let the VM thread know that this thread is ready for GC. The problem
2224 // of changing thread state is that safepoint could happen just after
2225 // java_suspend_self() returns after being resumed, and VM thread will
2226 // see the _thread_blocked state. We must check for safepoint
2227 // after restoring the state and make sure we won't leave while a safepoint
2228 // is in progress.
2229 thread->set_thread_state(_thread_blocked);
2230 thread->java_suspend_self();
2231 thread->set_thread_state(state);
2232 // Make sure new state is seen by VM thread
2233 if (os::is_MP()) {
2234 if (UseMembar) {
2235 // Force a fence between the write above and read below
2236 OrderAccess::fence();
2237 } else {
2238 // Must use this rather than serialization page in particular on Windows
2239 InterfaceSupport::serialize_memory(thread);
2240 }
2241 }
2242 }
2244 if (SafepointSynchronize::do_call_back()) {
2245 // If we are safepointing, then block the caller which may not be
2246 // the same as the target thread (see above).
2247 SafepointSynchronize::block(curJT);
2248 }
2250 if (thread->is_deopt_suspend()) {
2251 thread->clear_deopt_suspend();
2252 RegisterMap map(thread, false);
2253 frame f = thread->last_frame();
2254 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2255 f = f.sender(&map);
2256 }
2257 if (f.id() == thread->must_deopt_id()) {
2258 thread->clear_must_deopt_id();
2259 f.deoptimize(thread);
2260 } else {
2261 fatal("missed deoptimization!");
2262 }
2263 }
2264 }
2266 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2267 // progress or when _suspend_flags is non-zero.
2268 // Current thread needs to self-suspend if there is a suspend request and/or
2269 // block if a safepoint is in progress.
2270 // Also check for pending async exception (not including unsafe access error).
2271 // Note only the native==>VM/Java barriers can call this function and when
2272 // thread state is _thread_in_native_trans.
2273 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2274 check_safepoint_and_suspend_for_native_trans(thread);
2276 if (thread->has_async_exception()) {
2277 // We are in _thread_in_native_trans state, don't handle unsafe
2278 // access error since that may block.
2279 thread->check_and_handle_async_exceptions(false);
2280 }
2281 }
2283 // We need to guarantee the Threads_lock here, since resumes are not
2284 // allowed during safepoint synchronization
2285 // Can only resume from an external suspension
2286 void JavaThread::java_resume() {
2287 assert_locked_or_safepoint(Threads_lock);
2289 // Sanity check: thread is gone, has started exiting or the thread
2290 // was not externally suspended.
2291 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2292 return;
2293 }
2295 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2297 clear_external_suspend();
2299 if (is_ext_suspended()) {
2300 clear_ext_suspended();
2301 SR_lock()->notify_all();
2302 }
2303 }
2305 void JavaThread::create_stack_guard_pages() {
2306 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2307 address low_addr = stack_base() - stack_size();
2308 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2310 int allocate = os::allocate_stack_guard_pages();
2311 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2313 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2314 warning("Attempt to allocate stack guard pages failed.");
2315 return;
2316 }
2318 if (os::guard_memory((char *) low_addr, len)) {
2319 _stack_guard_state = stack_guard_enabled;
2320 } else {
2321 warning("Attempt to protect stack guard pages failed.");
2322 if (os::uncommit_memory((char *) low_addr, len)) {
2323 warning("Attempt to deallocate stack guard pages failed.");
2324 }
2325 }
2326 }
2328 void JavaThread::remove_stack_guard_pages() {
2329 if (_stack_guard_state == stack_guard_unused) return;
2330 address low_addr = stack_base() - stack_size();
2331 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2333 if (os::allocate_stack_guard_pages()) {
2334 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2335 _stack_guard_state = stack_guard_unused;
2336 } else {
2337 warning("Attempt to deallocate stack guard pages failed.");
2338 }
2339 } else {
2340 if (_stack_guard_state == stack_guard_unused) return;
2341 if (os::unguard_memory((char *) low_addr, len)) {
2342 _stack_guard_state = stack_guard_unused;
2343 } else {
2344 warning("Attempt to unprotect stack guard pages failed.");
2345 }
2346 }
2347 }
2349 void JavaThread::enable_stack_yellow_zone() {
2350 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2351 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2353 // The base notation is from the stacks point of view, growing downward.
2354 // We need to adjust it to work correctly with guard_memory()
2355 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2357 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2358 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2360 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2361 _stack_guard_state = stack_guard_enabled;
2362 } else {
2363 warning("Attempt to guard stack yellow zone failed.");
2364 }
2365 enable_register_stack_guard();
2366 }
2368 void JavaThread::disable_stack_yellow_zone() {
2369 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2370 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2372 // Simply return if called for a thread that does not use guard pages.
2373 if (_stack_guard_state == stack_guard_unused) return;
2375 // The base notation is from the stacks point of view, growing downward.
2376 // We need to adjust it to work correctly with guard_memory()
2377 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2379 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2380 _stack_guard_state = stack_guard_yellow_disabled;
2381 } else {
2382 warning("Attempt to unguard stack yellow zone failed.");
2383 }
2384 disable_register_stack_guard();
2385 }
2387 void JavaThread::enable_stack_red_zone() {
2388 // The base notation is from the stacks point of view, growing downward.
2389 // We need to adjust it to work correctly with guard_memory()
2390 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2391 address base = stack_red_zone_base() - stack_red_zone_size();
2393 guarantee(base < stack_base(),"Error calculating stack red zone");
2394 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2396 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2397 warning("Attempt to guard stack red zone failed.");
2398 }
2399 }
2401 void JavaThread::disable_stack_red_zone() {
2402 // The base notation is from the stacks point of view, growing downward.
2403 // We need to adjust it to work correctly with guard_memory()
2404 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2405 address base = stack_red_zone_base() - stack_red_zone_size();
2406 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2407 warning("Attempt to unguard stack red zone failed.");
2408 }
2409 }
2411 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2412 // ignore is there is no stack
2413 if (!has_last_Java_frame()) return;
2414 // traverse the stack frames. Starts from top frame.
2415 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2416 frame* fr = fst.current();
2417 f(fr, fst.register_map());
2418 }
2419 }
2422 #ifndef PRODUCT
2423 // Deoptimization
2424 // Function for testing deoptimization
2425 void JavaThread::deoptimize() {
2426 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2427 StackFrameStream fst(this, UseBiasedLocking);
2428 bool deopt = false; // Dump stack only if a deopt actually happens.
2429 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2430 // Iterate over all frames in the thread and deoptimize
2431 for(; !fst.is_done(); fst.next()) {
2432 if(fst.current()->can_be_deoptimized()) {
2434 if (only_at) {
2435 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2436 // consists of comma or carriage return separated numbers so
2437 // search for the current bci in that string.
2438 address pc = fst.current()->pc();
2439 nmethod* nm = (nmethod*) fst.current()->cb();
2440 ScopeDesc* sd = nm->scope_desc_at( pc);
2441 char buffer[8];
2442 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2443 size_t len = strlen(buffer);
2444 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2445 while (found != NULL) {
2446 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2447 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2448 // Check that the bci found is bracketed by terminators.
2449 break;
2450 }
2451 found = strstr(found + 1, buffer);
2452 }
2453 if (!found) {
2454 continue;
2455 }
2456 }
2458 if (DebugDeoptimization && !deopt) {
2459 deopt = true; // One-time only print before deopt
2460 tty->print_cr("[BEFORE Deoptimization]");
2461 trace_frames();
2462 trace_stack();
2463 }
2464 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2465 }
2466 }
2468 if (DebugDeoptimization && deopt) {
2469 tty->print_cr("[AFTER Deoptimization]");
2470 trace_frames();
2471 }
2472 }
2475 // Make zombies
2476 void JavaThread::make_zombies() {
2477 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2478 if (fst.current()->can_be_deoptimized()) {
2479 // it is a Java nmethod
2480 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2481 nm->make_not_entrant();
2482 }
2483 }
2484 }
2485 #endif // PRODUCT
2488 void JavaThread::deoptimized_wrt_marked_nmethods() {
2489 if (!has_last_Java_frame()) return;
2490 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2491 StackFrameStream fst(this, UseBiasedLocking);
2492 for(; !fst.is_done(); fst.next()) {
2493 if (fst.current()->should_be_deoptimized()) {
2494 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2495 }
2496 }
2497 }
2500 // GC support
2501 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2503 void JavaThread::gc_epilogue() {
2504 frames_do(frame_gc_epilogue);
2505 }
2508 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2510 void JavaThread::gc_prologue() {
2511 frames_do(frame_gc_prologue);
2512 }
2514 // If the caller is a NamedThread, then remember, in the current scope,
2515 // the given JavaThread in its _processed_thread field.
2516 class RememberProcessedThread: public StackObj {
2517 NamedThread* _cur_thr;
2518 public:
2519 RememberProcessedThread(JavaThread* jthr) {
2520 Thread* thread = Thread::current();
2521 if (thread->is_Named_thread()) {
2522 _cur_thr = (NamedThread *)thread;
2523 _cur_thr->set_processed_thread(jthr);
2524 } else {
2525 _cur_thr = NULL;
2526 }
2527 }
2529 ~RememberProcessedThread() {
2530 if (_cur_thr) {
2531 _cur_thr->set_processed_thread(NULL);
2532 }
2533 }
2534 };
2536 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2537 // Verify that the deferred card marks have been flushed.
2538 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2540 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2541 // since there may be more than one thread using each ThreadProfiler.
2543 // Traverse the GCHandles
2544 Thread::oops_do(f, cf);
2546 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2547 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2549 if (has_last_Java_frame()) {
2550 // Record JavaThread to GC thread
2551 RememberProcessedThread rpt(this);
2553 // Traverse the privileged stack
2554 if (_privileged_stack_top != NULL) {
2555 _privileged_stack_top->oops_do(f);
2556 }
2558 // traverse the registered growable array
2559 if (_array_for_gc != NULL) {
2560 for (int index = 0; index < _array_for_gc->length(); index++) {
2561 f->do_oop(_array_for_gc->adr_at(index));
2562 }
2563 }
2565 // Traverse the monitor chunks
2566 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2567 chunk->oops_do(f);
2568 }
2570 // Traverse the execution stack
2571 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2572 fst.current()->oops_do(f, cf, fst.register_map());
2573 }
2574 }
2576 // callee_target is never live across a gc point so NULL it here should
2577 // it still contain a methdOop.
2579 set_callee_target(NULL);
2581 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2582 // If we have deferred set_locals there might be oops waiting to be
2583 // written
2584 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2585 if (list != NULL) {
2586 for (int i = 0; i < list->length(); i++) {
2587 list->at(i)->oops_do(f);
2588 }
2589 }
2591 // Traverse instance variables at the end since the GC may be moving things
2592 // around using this function
2593 f->do_oop((oop*) &_threadObj);
2594 f->do_oop((oop*) &_vm_result);
2595 f->do_oop((oop*) &_vm_result_2);
2596 f->do_oop((oop*) &_exception_oop);
2597 f->do_oop((oop*) &_pending_async_exception);
2599 if (jvmti_thread_state() != NULL) {
2600 jvmti_thread_state()->oops_do(f);
2601 }
2602 }
2604 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2605 Thread::nmethods_do(cf); // (super method is a no-op)
2607 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2608 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2610 if (has_last_Java_frame()) {
2611 // Traverse the execution stack
2612 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2613 fst.current()->nmethods_do(cf);
2614 }
2615 }
2616 }
2618 // Printing
2619 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2620 switch (_thread_state) {
2621 case _thread_uninitialized: return "_thread_uninitialized";
2622 case _thread_new: return "_thread_new";
2623 case _thread_new_trans: return "_thread_new_trans";
2624 case _thread_in_native: return "_thread_in_native";
2625 case _thread_in_native_trans: return "_thread_in_native_trans";
2626 case _thread_in_vm: return "_thread_in_vm";
2627 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2628 case _thread_in_Java: return "_thread_in_Java";
2629 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2630 case _thread_blocked: return "_thread_blocked";
2631 case _thread_blocked_trans: return "_thread_blocked_trans";
2632 default: return "unknown thread state";
2633 }
2634 }
2636 #ifndef PRODUCT
2637 void JavaThread::print_thread_state_on(outputStream *st) const {
2638 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2639 };
2640 void JavaThread::print_thread_state() const {
2641 print_thread_state_on(tty);
2642 };
2643 #endif // PRODUCT
2645 // Called by Threads::print() for VM_PrintThreads operation
2646 void JavaThread::print_on(outputStream *st) const {
2647 st->print("\"%s\" ", get_thread_name());
2648 oop thread_oop = threadObj();
2649 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2650 Thread::print_on(st);
2651 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2652 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2653 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2654 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2655 }
2656 #ifndef PRODUCT
2657 print_thread_state_on(st);
2658 _safepoint_state->print_on(st);
2659 #endif // PRODUCT
2660 }
2662 // Called by fatal error handler. The difference between this and
2663 // JavaThread::print() is that we can't grab lock or allocate memory.
2664 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2665 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2666 oop thread_obj = threadObj();
2667 if (thread_obj != NULL) {
2668 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2669 }
2670 st->print(" [");
2671 st->print("%s", _get_thread_state_name(_thread_state));
2672 if (osthread()) {
2673 st->print(", id=%d", osthread()->thread_id());
2674 }
2675 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2676 _stack_base - _stack_size, _stack_base);
2677 st->print("]");
2678 return;
2679 }
2681 // Verification
2683 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2685 void JavaThread::verify() {
2686 // Verify oops in the thread.
2687 oops_do(&VerifyOopClosure::verify_oop, NULL);
2689 // Verify the stack frames.
2690 frames_do(frame_verify);
2691 }
2693 // CR 6300358 (sub-CR 2137150)
2694 // Most callers of this method assume that it can't return NULL but a
2695 // thread may not have a name whilst it is in the process of attaching to
2696 // the VM - see CR 6412693, and there are places where a JavaThread can be
2697 // seen prior to having it's threadObj set (eg JNI attaching threads and
2698 // if vm exit occurs during initialization). These cases can all be accounted
2699 // for such that this method never returns NULL.
2700 const char* JavaThread::get_thread_name() const {
2701 #ifdef ASSERT
2702 // early safepoints can hit while current thread does not yet have TLS
2703 if (!SafepointSynchronize::is_at_safepoint()) {
2704 Thread *cur = Thread::current();
2705 if (!(cur->is_Java_thread() && cur == this)) {
2706 // Current JavaThreads are allowed to get their own name without
2707 // the Threads_lock.
2708 assert_locked_or_safepoint(Threads_lock);
2709 }
2710 }
2711 #endif // ASSERT
2712 return get_thread_name_string();
2713 }
2715 // Returns a non-NULL representation of this thread's name, or a suitable
2716 // descriptive string if there is no set name
2717 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2718 const char* name_str;
2719 oop thread_obj = threadObj();
2720 if (thread_obj != NULL) {
2721 typeArrayOop name = java_lang_Thread::name(thread_obj);
2722 if (name != NULL) {
2723 if (buf == NULL) {
2724 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2725 }
2726 else {
2727 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2728 }
2729 }
2730 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2731 name_str = "<no-name - thread is attaching>";
2732 }
2733 else {
2734 name_str = Thread::name();
2735 }
2736 }
2737 else {
2738 name_str = Thread::name();
2739 }
2740 assert(name_str != NULL, "unexpected NULL thread name");
2741 return name_str;
2742 }
2745 const char* JavaThread::get_threadgroup_name() const {
2746 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2747 oop thread_obj = threadObj();
2748 if (thread_obj != NULL) {
2749 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2750 if (thread_group != NULL) {
2751 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2752 // ThreadGroup.name can be null
2753 if (name != NULL) {
2754 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2755 return str;
2756 }
2757 }
2758 }
2759 return NULL;
2760 }
2762 const char* JavaThread::get_parent_name() const {
2763 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2764 oop thread_obj = threadObj();
2765 if (thread_obj != NULL) {
2766 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2767 if (thread_group != NULL) {
2768 oop parent = java_lang_ThreadGroup::parent(thread_group);
2769 if (parent != NULL) {
2770 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2771 // ThreadGroup.name can be null
2772 if (name != NULL) {
2773 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2774 return str;
2775 }
2776 }
2777 }
2778 }
2779 return NULL;
2780 }
2782 ThreadPriority JavaThread::java_priority() const {
2783 oop thr_oop = threadObj();
2784 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2785 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2786 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2787 return priority;
2788 }
2790 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2792 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2793 // Link Java Thread object <-> C++ Thread
2795 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2796 // and put it into a new Handle. The Handle "thread_oop" can then
2797 // be used to pass the C++ thread object to other methods.
2799 // Set the Java level thread object (jthread) field of the
2800 // new thread (a JavaThread *) to C++ thread object using the
2801 // "thread_oop" handle.
2803 // Set the thread field (a JavaThread *) of the
2804 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2806 Handle thread_oop(Thread::current(),
2807 JNIHandles::resolve_non_null(jni_thread));
2808 assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
2809 "must be initialized");
2810 set_threadObj(thread_oop());
2811 java_lang_Thread::set_thread(thread_oop(), this);
2813 if (prio == NoPriority) {
2814 prio = java_lang_Thread::priority(thread_oop());
2815 assert(prio != NoPriority, "A valid priority should be present");
2816 }
2818 // Push the Java priority down to the native thread; needs Threads_lock
2819 Thread::set_priority(this, prio);
2821 // Add the new thread to the Threads list and set it in motion.
2822 // We must have threads lock in order to call Threads::add.
2823 // It is crucial that we do not block before the thread is
2824 // added to the Threads list for if a GC happens, then the java_thread oop
2825 // will not be visited by GC.
2826 Threads::add(this);
2827 }
2829 oop JavaThread::current_park_blocker() {
2830 // Support for JSR-166 locks
2831 oop thread_oop = threadObj();
2832 if (thread_oop != NULL &&
2833 JDK_Version::current().supports_thread_park_blocker()) {
2834 return java_lang_Thread::park_blocker(thread_oop);
2835 }
2836 return NULL;
2837 }
2840 void JavaThread::print_stack_on(outputStream* st) {
2841 if (!has_last_Java_frame()) return;
2842 ResourceMark rm;
2843 HandleMark hm;
2845 RegisterMap reg_map(this);
2846 vframe* start_vf = last_java_vframe(®_map);
2847 int count = 0;
2848 for (vframe* f = start_vf; f; f = f->sender() ) {
2849 if (f->is_java_frame()) {
2850 javaVFrame* jvf = javaVFrame::cast(f);
2851 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2853 // Print out lock information
2854 if (JavaMonitorsInStackTrace) {
2855 jvf->print_lock_info_on(st, count);
2856 }
2857 } else {
2858 // Ignore non-Java frames
2859 }
2861 // Bail-out case for too deep stacks
2862 count++;
2863 if (MaxJavaStackTraceDepth == count) return;
2864 }
2865 }
2868 // JVMTI PopFrame support
2869 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2870 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2871 if (in_bytes(size_in_bytes) != 0) {
2872 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes));
2873 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2874 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2875 }
2876 }
2878 void* JavaThread::popframe_preserved_args() {
2879 return _popframe_preserved_args;
2880 }
2882 ByteSize JavaThread::popframe_preserved_args_size() {
2883 return in_ByteSize(_popframe_preserved_args_size);
2884 }
2886 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2887 int sz = in_bytes(popframe_preserved_args_size());
2888 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2889 return in_WordSize(sz / wordSize);
2890 }
2892 void JavaThread::popframe_free_preserved_args() {
2893 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2894 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
2895 _popframe_preserved_args = NULL;
2896 _popframe_preserved_args_size = 0;
2897 }
2899 #ifndef PRODUCT
2901 void JavaThread::trace_frames() {
2902 tty->print_cr("[Describe stack]");
2903 int frame_no = 1;
2904 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2905 tty->print(" %d. ", frame_no++);
2906 fst.current()->print_value_on(tty,this);
2907 tty->cr();
2908 }
2909 }
2911 class PrintAndVerifyOopClosure: public OopClosure {
2912 protected:
2913 template <class T> inline void do_oop_work(T* p) {
2914 oop obj = oopDesc::load_decode_heap_oop(p);
2915 if (obj == NULL) return;
2916 tty->print(INTPTR_FORMAT ": ", p);
2917 if (obj->is_oop_or_null()) {
2918 if (obj->is_objArray()) {
2919 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
2920 } else {
2921 obj->print();
2922 }
2923 } else {
2924 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
2925 }
2926 tty->cr();
2927 }
2928 public:
2929 virtual void do_oop(oop* p) { do_oop_work(p); }
2930 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
2931 };
2934 static void oops_print(frame* f, const RegisterMap *map) {
2935 PrintAndVerifyOopClosure print;
2936 f->print_value();
2937 f->oops_do(&print, NULL, (RegisterMap*)map);
2938 }
2940 // Print our all the locations that contain oops and whether they are
2941 // valid or not. This useful when trying to find the oldest frame
2942 // where an oop has gone bad since the frame walk is from youngest to
2943 // oldest.
2944 void JavaThread::trace_oops() {
2945 tty->print_cr("[Trace oops]");
2946 frames_do(oops_print);
2947 }
2950 #ifdef ASSERT
2951 // Print or validate the layout of stack frames
2952 void JavaThread::print_frame_layout(int depth, bool validate_only) {
2953 ResourceMark rm;
2954 PRESERVE_EXCEPTION_MARK;
2955 FrameValues values;
2956 int frame_no = 0;
2957 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
2958 fst.current()->describe(values, ++frame_no);
2959 if (depth == frame_no) break;
2960 }
2961 if (validate_only) {
2962 values.validate();
2963 } else {
2964 tty->print_cr("[Describe stack layout]");
2965 values.print(this);
2966 }
2967 }
2968 #endif
2970 void JavaThread::trace_stack_from(vframe* start_vf) {
2971 ResourceMark rm;
2972 int vframe_no = 1;
2973 for (vframe* f = start_vf; f; f = f->sender() ) {
2974 if (f->is_java_frame()) {
2975 javaVFrame::cast(f)->print_activation(vframe_no++);
2976 } else {
2977 f->print();
2978 }
2979 if (vframe_no > StackPrintLimit) {
2980 tty->print_cr("...<more frames>...");
2981 return;
2982 }
2983 }
2984 }
2987 void JavaThread::trace_stack() {
2988 if (!has_last_Java_frame()) return;
2989 ResourceMark rm;
2990 HandleMark hm;
2991 RegisterMap reg_map(this);
2992 trace_stack_from(last_java_vframe(®_map));
2993 }
2996 #endif // PRODUCT
2999 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3000 assert(reg_map != NULL, "a map must be given");
3001 frame f = last_frame();
3002 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3003 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3004 }
3005 return NULL;
3006 }
3009 klassOop JavaThread::security_get_caller_class(int depth) {
3010 vframeStream vfst(this);
3011 vfst.security_get_caller_frame(depth);
3012 if (!vfst.at_end()) {
3013 return vfst.method()->method_holder();
3014 }
3015 return NULL;
3016 }
3018 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3019 assert(thread->is_Compiler_thread(), "must be compiler thread");
3020 CompileBroker::compiler_thread_loop();
3021 }
3023 // Create a CompilerThread
3024 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3025 : JavaThread(&compiler_thread_entry) {
3026 _env = NULL;
3027 _log = NULL;
3028 _task = NULL;
3029 _queue = queue;
3030 _counters = counters;
3031 _buffer_blob = NULL;
3032 _scanned_nmethod = NULL;
3034 #ifndef PRODUCT
3035 _ideal_graph_printer = NULL;
3036 #endif
3037 }
3039 void CompilerThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3040 JavaThread::oops_do(f, cf);
3041 if (_scanned_nmethod != NULL && cf != NULL) {
3042 // Safepoints can occur when the sweeper is scanning an nmethod so
3043 // process it here to make sure it isn't unloaded in the middle of
3044 // a scan.
3045 cf->do_code_blob(_scanned_nmethod);
3046 }
3047 }
3049 // ======= Threads ========
3051 // The Threads class links together all active threads, and provides
3052 // operations over all threads. It is protected by its own Mutex
3053 // lock, which is also used in other contexts to protect thread
3054 // operations from having the thread being operated on from exiting
3055 // and going away unexpectedly (e.g., safepoint synchronization)
3057 JavaThread* Threads::_thread_list = NULL;
3058 int Threads::_number_of_threads = 0;
3059 int Threads::_number_of_non_daemon_threads = 0;
3060 int Threads::_return_code = 0;
3061 size_t JavaThread::_stack_size_at_create = 0;
3063 // All JavaThreads
3064 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3066 void os_stream();
3068 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3069 void Threads::threads_do(ThreadClosure* tc) {
3070 assert_locked_or_safepoint(Threads_lock);
3071 // ALL_JAVA_THREADS iterates through all JavaThreads
3072 ALL_JAVA_THREADS(p) {
3073 tc->do_thread(p);
3074 }
3075 // Someday we could have a table or list of all non-JavaThreads.
3076 // For now, just manually iterate through them.
3077 tc->do_thread(VMThread::vm_thread());
3078 Universe::heap()->gc_threads_do(tc);
3079 WatcherThread *wt = WatcherThread::watcher_thread();
3080 // Strictly speaking, the following NULL check isn't sufficient to make sure
3081 // the data for WatcherThread is still valid upon being examined. However,
3082 // considering that WatchThread terminates when the VM is on the way to
3083 // exit at safepoint, the chance of the above is extremely small. The right
3084 // way to prevent termination of WatcherThread would be to acquire
3085 // Terminator_lock, but we can't do that without violating the lock rank
3086 // checking in some cases.
3087 if (wt != NULL)
3088 tc->do_thread(wt);
3090 // If CompilerThreads ever become non-JavaThreads, add them here
3091 }
3093 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3095 extern void JDK_Version_init();
3097 // Check version
3098 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3100 // Initialize the output stream module
3101 ostream_init();
3103 // Process java launcher properties.
3104 Arguments::process_sun_java_launcher_properties(args);
3106 // Initialize the os module before using TLS
3107 os::init();
3109 // Initialize system properties.
3110 Arguments::init_system_properties();
3112 // So that JDK version can be used as a discrimintor when parsing arguments
3113 JDK_Version_init();
3115 // Update/Initialize System properties after JDK version number is known
3116 Arguments::init_version_specific_system_properties();
3118 // Parse arguments
3119 jint parse_result = Arguments::parse(args);
3120 if (parse_result != JNI_OK) return parse_result;
3122 if (PauseAtStartup) {
3123 os::pause();
3124 }
3126 #ifndef USDT2
3127 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3128 #else /* USDT2 */
3129 HOTSPOT_VM_INIT_BEGIN();
3130 #endif /* USDT2 */
3132 // Record VM creation timing statistics
3133 TraceVmCreationTime create_vm_timer;
3134 create_vm_timer.start();
3136 // Timing (must come after argument parsing)
3137 TraceTime timer("Create VM", TraceStartupTime);
3139 // Initialize the os module after parsing the args
3140 jint os_init_2_result = os::init_2();
3141 if (os_init_2_result != JNI_OK) return os_init_2_result;
3143 // Initialize output stream logging
3144 ostream_init_log();
3146 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3147 // Must be before create_vm_init_agents()
3148 if (Arguments::init_libraries_at_startup()) {
3149 convert_vm_init_libraries_to_agents();
3150 }
3152 // Launch -agentlib/-agentpath and converted -Xrun agents
3153 if (Arguments::init_agents_at_startup()) {
3154 create_vm_init_agents();
3155 }
3157 // Initialize Threads state
3158 _thread_list = NULL;
3159 _number_of_threads = 0;
3160 _number_of_non_daemon_threads = 0;
3162 // Initialize TLS
3163 ThreadLocalStorage::init();
3165 // Initialize global data structures and create system classes in heap
3166 vm_init_globals();
3168 // Attach the main thread to this os thread
3169 JavaThread* main_thread = new JavaThread();
3170 main_thread->set_thread_state(_thread_in_vm);
3171 // must do this before set_active_handles and initialize_thread_local_storage
3172 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3173 // change the stack size recorded here to one based on the java thread
3174 // stacksize. This adjusted size is what is used to figure the placement
3175 // of the guard pages.
3176 main_thread->record_stack_base_and_size();
3177 main_thread->initialize_thread_local_storage();
3179 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3181 if (!main_thread->set_as_starting_thread()) {
3182 vm_shutdown_during_initialization(
3183 "Failed necessary internal allocation. Out of swap space");
3184 delete main_thread;
3185 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3186 return JNI_ENOMEM;
3187 }
3189 // Enable guard page *after* os::create_main_thread(), otherwise it would
3190 // crash Linux VM, see notes in os_linux.cpp.
3191 main_thread->create_stack_guard_pages();
3193 // Initialize Java-Level synchronization subsystem
3194 ObjectMonitor::Initialize() ;
3196 // Initialize global modules
3197 jint status = init_globals();
3198 if (status != JNI_OK) {
3199 delete main_thread;
3200 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3201 return status;
3202 }
3204 // Must be run after init_ft which initializes ft_enabled
3205 if (TRACE_INITIALIZE() != JNI_OK) {
3206 vm_exit_during_initialization("Failed to initialize tracing backend");
3207 }
3209 // Should be done after the heap is fully created
3210 main_thread->cache_global_variables();
3212 HandleMark hm;
3214 { MutexLocker mu(Threads_lock);
3215 Threads::add(main_thread);
3216 }
3218 // Any JVMTI raw monitors entered in onload will transition into
3219 // real raw monitor. VM is setup enough here for raw monitor enter.
3220 JvmtiExport::transition_pending_onload_raw_monitors();
3222 if (VerifyBeforeGC &&
3223 Universe::heap()->total_collections() >= VerifyGCStartAt) {
3224 Universe::heap()->prepare_for_verify();
3225 Universe::verify(); // make sure we're starting with a clean slate
3226 }
3228 // Create the VMThread
3229 { TraceTime timer("Start VMThread", TraceStartupTime);
3230 VMThread::create();
3231 Thread* vmthread = VMThread::vm_thread();
3233 if (!os::create_thread(vmthread, os::vm_thread))
3234 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3236 // Wait for the VM thread to become ready, and VMThread::run to initialize
3237 // Monitors can have spurious returns, must always check another state flag
3238 {
3239 MutexLocker ml(Notify_lock);
3240 os::start_thread(vmthread);
3241 while (vmthread->active_handles() == NULL) {
3242 Notify_lock->wait();
3243 }
3244 }
3245 }
3247 assert (Universe::is_fully_initialized(), "not initialized");
3248 EXCEPTION_MARK;
3250 // At this point, the Universe is initialized, but we have not executed
3251 // any byte code. Now is a good time (the only time) to dump out the
3252 // internal state of the JVM for sharing.
3254 if (DumpSharedSpaces) {
3255 Universe::heap()->preload_and_dump(CHECK_0);
3256 ShouldNotReachHere();
3257 }
3259 // Always call even when there are not JVMTI environments yet, since environments
3260 // may be attached late and JVMTI must track phases of VM execution
3261 JvmtiExport::enter_start_phase();
3263 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3264 JvmtiExport::post_vm_start();
3266 {
3267 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3269 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3270 create_vm_init_libraries();
3271 }
3273 if (InitializeJavaLangString) {
3274 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3275 } else {
3276 warning("java.lang.String not initialized");
3277 }
3279 if (AggressiveOpts) {
3280 {
3281 // Forcibly initialize java/util/HashMap and mutate the private
3282 // static final "frontCacheEnabled" field before we start creating instances
3283 #ifdef ASSERT
3284 klassOop tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3285 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
3286 #endif
3287 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3288 KlassHandle k = KlassHandle(THREAD, k_o);
3289 guarantee(k.not_null(), "Must find java/util/HashMap");
3290 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3291 ik->initialize(CHECK_0);
3292 fieldDescriptor fd;
3293 // Possible we might not find this field; if so, don't break
3294 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3295 k()->java_mirror()->bool_field_put(fd.offset(), true);
3296 }
3297 }
3299 if (UseStringCache) {
3300 // Forcibly initialize java/lang/StringValue and mutate the private
3301 // static final "stringCacheEnabled" field before we start creating instances
3302 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3303 // Possible that StringValue isn't present: if so, silently don't break
3304 if (k_o != NULL) {
3305 KlassHandle k = KlassHandle(THREAD, k_o);
3306 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3307 ik->initialize(CHECK_0);
3308 fieldDescriptor fd;
3309 // Possible we might not find this field: if so, silently don't break
3310 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3311 k()->java_mirror()->bool_field_put(fd.offset(), true);
3312 }
3313 }
3314 }
3315 }
3317 // Initialize java_lang.System (needed before creating the thread)
3318 if (InitializeJavaLangSystem) {
3319 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3320 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3321 Handle thread_group = create_initial_thread_group(CHECK_0);
3322 Universe::set_main_thread_group(thread_group());
3323 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3324 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3325 main_thread->set_threadObj(thread_object);
3326 // Set thread status to running since main thread has
3327 // been started and running.
3328 java_lang_Thread::set_thread_status(thread_object,
3329 java_lang_Thread::RUNNABLE);
3331 // The VM preresolve methods to these classes. Make sure that get initialized
3332 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3333 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3334 // The VM creates & returns objects of this class. Make sure it's initialized.
3335 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3336 call_initializeSystemClass(CHECK_0);
3337 } else {
3338 warning("java.lang.System not initialized");
3339 }
3341 // an instance of OutOfMemory exception has been allocated earlier
3342 if (InitializeJavaLangExceptionsErrors) {
3343 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3344 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3345 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3346 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3347 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3348 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3349 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3350 } else {
3351 warning("java.lang.OutOfMemoryError has not been initialized");
3352 warning("java.lang.NullPointerException has not been initialized");
3353 warning("java.lang.ClassCastException has not been initialized");
3354 warning("java.lang.ArrayStoreException has not been initialized");
3355 warning("java.lang.ArithmeticException has not been initialized");
3356 warning("java.lang.StackOverflowError has not been initialized");
3357 }
3358 }
3360 // See : bugid 4211085.
3361 // Background : the static initializer of java.lang.Compiler tries to read
3362 // property"java.compiler" and read & write property "java.vm.info".
3363 // When a security manager is installed through the command line
3364 // option "-Djava.security.manager", the above properties are not
3365 // readable and the static initializer for java.lang.Compiler fails
3366 // resulting in a NoClassDefFoundError. This can happen in any
3367 // user code which calls methods in java.lang.Compiler.
3368 // Hack : the hack is to pre-load and initialize this class, so that only
3369 // system domains are on the stack when the properties are read.
3370 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3371 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3372 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3373 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3374 // Once that is done, we should remove this hack.
3375 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3377 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3378 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3379 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3380 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3381 // This should also be taken out as soon as 4211383 gets fixed.
3382 reset_vm_info_property(CHECK_0);
3384 quicken_jni_functions();
3386 // Set flag that basic initialization has completed. Used by exceptions and various
3387 // debug stuff, that does not work until all basic classes have been initialized.
3388 set_init_completed();
3390 #ifndef USDT2
3391 HS_DTRACE_PROBE(hotspot, vm__init__end);
3392 #else /* USDT2 */
3393 HOTSPOT_VM_INIT_END();
3394 #endif /* USDT2 */
3396 // record VM initialization completion time
3397 Management::record_vm_init_completed();
3399 // Compute system loader. Note that this has to occur after set_init_completed, since
3400 // valid exceptions may be thrown in the process.
3401 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3402 // set_init_completed has just been called, causing exceptions not to be shortcut
3403 // anymore. We call vm_exit_during_initialization directly instead.
3404 SystemDictionary::compute_java_system_loader(THREAD);
3405 if (HAS_PENDING_EXCEPTION) {
3406 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3407 }
3409 #ifndef SERIALGC
3410 // Support for ConcurrentMarkSweep. This should be cleaned up
3411 // and better encapsulated. The ugly nested if test would go away
3412 // once things are properly refactored. XXX YSR
3413 if (UseConcMarkSweepGC || UseG1GC) {
3414 if (UseConcMarkSweepGC) {
3415 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3416 } else {
3417 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3418 }
3419 if (HAS_PENDING_EXCEPTION) {
3420 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3421 }
3422 }
3423 #endif // SERIALGC
3425 // Always call even when there are not JVMTI environments yet, since environments
3426 // may be attached late and JVMTI must track phases of VM execution
3427 JvmtiExport::enter_live_phase();
3429 // Signal Dispatcher needs to be started before VMInit event is posted
3430 os::signal_init();
3432 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3433 if (!DisableAttachMechanism) {
3434 if (StartAttachListener || AttachListener::init_at_startup()) {
3435 AttachListener::init();
3436 }
3437 }
3439 // Launch -Xrun agents
3440 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3441 // back-end can launch with -Xdebug -Xrunjdwp.
3442 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3443 create_vm_init_libraries();
3444 }
3446 if (!TRACE_START()) {
3447 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3448 }
3450 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3451 JvmtiExport::post_vm_initialized();
3453 if (CleanChunkPoolAsync) {
3454 Chunk::start_chunk_pool_cleaner_task();
3455 }
3457 // initialize compiler(s)
3458 CompileBroker::compilation_init();
3460 Management::initialize(THREAD);
3461 if (HAS_PENDING_EXCEPTION) {
3462 // management agent fails to start possibly due to
3463 // configuration problem and is responsible for printing
3464 // stack trace if appropriate. Simply exit VM.
3465 vm_exit(1);
3466 }
3468 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3469 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3470 if (MemProfiling) MemProfiler::engage();
3471 StatSampler::engage();
3472 if (CheckJNICalls) JniPeriodicChecker::engage();
3474 BiasedLocking::init();
3476 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3477 call_postVMInitHook(THREAD);
3478 // The Java side of PostVMInitHook.run must deal with all
3479 // exceptions and provide means of diagnosis.
3480 if (HAS_PENDING_EXCEPTION) {
3481 CLEAR_PENDING_EXCEPTION;
3482 }
3483 }
3485 // Start up the WatcherThread if there are any periodic tasks
3486 // NOTE: All PeriodicTasks should be registered by now. If they
3487 // aren't, late joiners might appear to start slowly (we might
3488 // take a while to process their first tick).
3489 if (PeriodicTask::num_tasks() > 0) {
3490 WatcherThread::start();
3491 }
3493 // Give os specific code one last chance to start
3494 os::init_3();
3496 create_vm_timer.end();
3497 return JNI_OK;
3498 }
3500 // type for the Agent_OnLoad and JVM_OnLoad entry points
3501 extern "C" {
3502 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3503 }
3504 // Find a command line agent library and return its entry point for
3505 // -agentlib: -agentpath: -Xrun
3506 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3507 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3508 OnLoadEntry_t on_load_entry = NULL;
3509 void *library = agent->os_lib(); // check if we have looked it up before
3511 if (library == NULL) {
3512 char buffer[JVM_MAXPATHLEN];
3513 char ebuf[1024];
3514 const char *name = agent->name();
3515 const char *msg = "Could not find agent library ";
3517 if (agent->is_absolute_path()) {
3518 library = os::dll_load(name, ebuf, sizeof ebuf);
3519 if (library == NULL) {
3520 const char *sub_msg = " in absolute path, with error: ";
3521 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3522 char *buf = NEW_C_HEAP_ARRAY(char, len);
3523 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3524 // If we can't find the agent, exit.
3525 vm_exit_during_initialization(buf, NULL);
3526 FREE_C_HEAP_ARRAY(char, buf);
3527 }
3528 } else {
3529 // Try to load the agent from the standard dll directory
3530 os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
3531 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3532 #ifdef KERNEL
3533 // Download instrument dll
3534 if (library == NULL && strcmp(name, "instrument") == 0) {
3535 char *props = Arguments::get_kernel_properties();
3536 char *home = Arguments::get_java_home();
3537 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false"
3538 " sun.jkernel.DownloadManager -download client_jvm";
3539 size_t length = strlen(props) + strlen(home) + strlen(fmt) + 1;
3540 char *cmd = NEW_C_HEAP_ARRAY(char, length);
3541 jio_snprintf(cmd, length, fmt, home, props);
3542 int status = os::fork_and_exec(cmd);
3543 FreeHeap(props);
3544 if (status == -1) {
3545 warning(cmd);
3546 vm_exit_during_initialization("fork_and_exec failed: %s",
3547 strerror(errno));
3548 }
3549 FREE_C_HEAP_ARRAY(char, cmd);
3550 // when this comes back the instrument.dll should be where it belongs.
3551 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3552 }
3553 #endif // KERNEL
3554 if (library == NULL) { // Try the local directory
3555 char ns[1] = {0};
3556 os::dll_build_name(buffer, sizeof(buffer), ns, name);
3557 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3558 if (library == NULL) {
3559 const char *sub_msg = " on the library path, with error: ";
3560 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3561 char *buf = NEW_C_HEAP_ARRAY(char, len);
3562 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3563 // If we can't find the agent, exit.
3564 vm_exit_during_initialization(buf, NULL);
3565 FREE_C_HEAP_ARRAY(char, buf);
3566 }
3567 }
3568 }
3569 agent->set_os_lib(library);
3570 }
3572 // Find the OnLoad function.
3573 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3574 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index]));
3575 if (on_load_entry != NULL) break;
3576 }
3577 return on_load_entry;
3578 }
3580 // Find the JVM_OnLoad entry point
3581 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3582 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3583 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3584 }
3586 // Find the Agent_OnLoad entry point
3587 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3588 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3589 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3590 }
3592 // For backwards compatibility with -Xrun
3593 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3594 // treated like -agentpath:
3595 // Must be called before agent libraries are created
3596 void Threads::convert_vm_init_libraries_to_agents() {
3597 AgentLibrary* agent;
3598 AgentLibrary* next;
3600 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3601 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3602 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3604 // If there is an JVM_OnLoad function it will get called later,
3605 // otherwise see if there is an Agent_OnLoad
3606 if (on_load_entry == NULL) {
3607 on_load_entry = lookup_agent_on_load(agent);
3608 if (on_load_entry != NULL) {
3609 // switch it to the agent list -- so that Agent_OnLoad will be called,
3610 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3611 Arguments::convert_library_to_agent(agent);
3612 } else {
3613 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3614 }
3615 }
3616 }
3617 }
3619 // Create agents for -agentlib: -agentpath: and converted -Xrun
3620 // Invokes Agent_OnLoad
3621 // Called very early -- before JavaThreads exist
3622 void Threads::create_vm_init_agents() {
3623 extern struct JavaVM_ main_vm;
3624 AgentLibrary* agent;
3626 JvmtiExport::enter_onload_phase();
3627 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3628 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3630 if (on_load_entry != NULL) {
3631 // Invoke the Agent_OnLoad function
3632 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3633 if (err != JNI_OK) {
3634 vm_exit_during_initialization("agent library failed to init", agent->name());
3635 }
3636 } else {
3637 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3638 }
3639 }
3640 JvmtiExport::enter_primordial_phase();
3641 }
3643 extern "C" {
3644 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3645 }
3647 void Threads::shutdown_vm_agents() {
3648 // Send any Agent_OnUnload notifications
3649 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3650 extern struct JavaVM_ main_vm;
3651 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3653 // Find the Agent_OnUnload function.
3654 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3655 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3656 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3658 // Invoke the Agent_OnUnload function
3659 if (unload_entry != NULL) {
3660 JavaThread* thread = JavaThread::current();
3661 ThreadToNativeFromVM ttn(thread);
3662 HandleMark hm(thread);
3663 (*unload_entry)(&main_vm);
3664 break;
3665 }
3666 }
3667 }
3668 }
3670 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3671 // Invokes JVM_OnLoad
3672 void Threads::create_vm_init_libraries() {
3673 extern struct JavaVM_ main_vm;
3674 AgentLibrary* agent;
3676 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3677 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3679 if (on_load_entry != NULL) {
3680 // Invoke the JVM_OnLoad function
3681 JavaThread* thread = JavaThread::current();
3682 ThreadToNativeFromVM ttn(thread);
3683 HandleMark hm(thread);
3684 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3685 if (err != JNI_OK) {
3686 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3687 }
3688 } else {
3689 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3690 }
3691 }
3692 }
3694 // Last thread running calls java.lang.Shutdown.shutdown()
3695 void JavaThread::invoke_shutdown_hooks() {
3696 HandleMark hm(this);
3698 // We could get here with a pending exception, if so clear it now.
3699 if (this->has_pending_exception()) {
3700 this->clear_pending_exception();
3701 }
3703 EXCEPTION_MARK;
3704 klassOop k =
3705 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3706 THREAD);
3707 if (k != NULL) {
3708 // SystemDictionary::resolve_or_null will return null if there was
3709 // an exception. If we cannot load the Shutdown class, just don't
3710 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3711 // and finalizers (if runFinalizersOnExit is set) won't be run.
3712 // Note that if a shutdown hook was registered or runFinalizersOnExit
3713 // was called, the Shutdown class would have already been loaded
3714 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3715 instanceKlassHandle shutdown_klass (THREAD, k);
3716 JavaValue result(T_VOID);
3717 JavaCalls::call_static(&result,
3718 shutdown_klass,
3719 vmSymbols::shutdown_method_name(),
3720 vmSymbols::void_method_signature(),
3721 THREAD);
3722 }
3723 CLEAR_PENDING_EXCEPTION;
3724 }
3726 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3727 // the program falls off the end of main(). Another VM exit path is through
3728 // vm_exit() when the program calls System.exit() to return a value or when
3729 // there is a serious error in VM. The two shutdown paths are not exactly
3730 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3731 // and VM_Exit op at VM level.
3732 //
3733 // Shutdown sequence:
3734 // + Wait until we are the last non-daemon thread to execute
3735 // <-- every thing is still working at this moment -->
3736 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3737 // shutdown hooks, run finalizers if finalization-on-exit
3738 // + Call before_exit(), prepare for VM exit
3739 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3740 // currently the only user of this mechanism is File.deleteOnExit())
3741 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3742 // post thread end and vm death events to JVMTI,
3743 // stop signal thread
3744 // + Call JavaThread::exit(), it will:
3745 // > release JNI handle blocks, remove stack guard pages
3746 // > remove this thread from Threads list
3747 // <-- no more Java code from this thread after this point -->
3748 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3749 // the compiler threads at safepoint
3750 // <-- do not use anything that could get blocked by Safepoint -->
3751 // + Disable tracing at JNI/JVM barriers
3752 // + Set _vm_exited flag for threads that are still running native code
3753 // + Delete this thread
3754 // + Call exit_globals()
3755 // > deletes tty
3756 // > deletes PerfMemory resources
3757 // + Return to caller
3759 bool Threads::destroy_vm() {
3760 JavaThread* thread = JavaThread::current();
3762 // Wait until we are the last non-daemon thread to execute
3763 { MutexLocker nu(Threads_lock);
3764 while (Threads::number_of_non_daemon_threads() > 1 )
3765 // This wait should make safepoint checks, wait without a timeout,
3766 // and wait as a suspend-equivalent condition.
3767 //
3768 // Note: If the FlatProfiler is running and this thread is waiting
3769 // for another non-daemon thread to finish, then the FlatProfiler
3770 // is waiting for the external suspend request on this thread to
3771 // complete. wait_for_ext_suspend_completion() will eventually
3772 // timeout, but that takes time. Making this wait a suspend-
3773 // equivalent condition solves that timeout problem.
3774 //
3775 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3776 Mutex::_as_suspend_equivalent_flag);
3777 }
3779 // Hang forever on exit if we are reporting an error.
3780 if (ShowMessageBoxOnError && is_error_reported()) {
3781 os::infinite_sleep();
3782 }
3783 os::wait_for_keypress_at_exit();
3785 if (JDK_Version::is_jdk12x_version()) {
3786 // We are the last thread running, so check if finalizers should be run.
3787 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3788 HandleMark rm(thread);
3789 Universe::run_finalizers_on_exit();
3790 } else {
3791 // run Java level shutdown hooks
3792 thread->invoke_shutdown_hooks();
3793 }
3795 before_exit(thread);
3797 thread->exit(true);
3799 // Stop VM thread.
3800 {
3801 // 4945125 The vm thread comes to a safepoint during exit.
3802 // GC vm_operations can get caught at the safepoint, and the
3803 // heap is unparseable if they are caught. Grab the Heap_lock
3804 // to prevent this. The GC vm_operations will not be able to
3805 // queue until after the vm thread is dead.
3806 // After this point, we'll never emerge out of the safepoint before
3807 // the VM exits, so concurrent GC threads do not need to be explicitly
3808 // stopped; they remain inactive until the process exits.
3809 // Note: some concurrent G1 threads may be running during a safepoint,
3810 // but these will not be accessing the heap, just some G1-specific side
3811 // data structures that are not accessed by any other threads but them
3812 // after this point in a terminal safepoint.
3814 MutexLocker ml(Heap_lock);
3816 VMThread::wait_for_vm_thread_exit();
3817 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3818 VMThread::destroy();
3819 }
3821 // clean up ideal graph printers
3822 #if defined(COMPILER2) && !defined(PRODUCT)
3823 IdealGraphPrinter::clean_up();
3824 #endif
3826 // Now, all Java threads are gone except daemon threads. Daemon threads
3827 // running Java code or in VM are stopped by the Safepoint. However,
3828 // daemon threads executing native code are still running. But they
3829 // will be stopped at native=>Java/VM barriers. Note that we can't
3830 // simply kill or suspend them, as it is inherently deadlock-prone.
3832 #ifndef PRODUCT
3833 // disable function tracing at JNI/JVM barriers
3834 TraceJNICalls = false;
3835 TraceJVMCalls = false;
3836 TraceRuntimeCalls = false;
3837 #endif
3839 VM_Exit::set_vm_exited();
3841 notify_vm_shutdown();
3843 delete thread;
3845 // exit_globals() will delete tty
3846 exit_globals();
3848 return true;
3849 }
3852 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3853 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3854 return is_supported_jni_version(version);
3855 }
3858 jboolean Threads::is_supported_jni_version(jint version) {
3859 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3860 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3861 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3862 return JNI_FALSE;
3863 }
3866 void Threads::add(JavaThread* p, bool force_daemon) {
3867 // The threads lock must be owned at this point
3868 assert_locked_or_safepoint(Threads_lock);
3870 // See the comment for this method in thread.hpp for its purpose and
3871 // why it is called here.
3872 p->initialize_queues();
3873 p->set_next(_thread_list);
3874 _thread_list = p;
3875 _number_of_threads++;
3876 oop threadObj = p->threadObj();
3877 bool daemon = true;
3878 // Bootstrapping problem: threadObj can be null for initial
3879 // JavaThread (or for threads attached via JNI)
3880 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3881 _number_of_non_daemon_threads++;
3882 daemon = false;
3883 }
3885 ThreadService::add_thread(p, daemon);
3887 // Possible GC point.
3888 Events::log("Thread added: " INTPTR_FORMAT, p);
3889 }
3891 void Threads::remove(JavaThread* p) {
3892 // Extra scope needed for Thread_lock, so we can check
3893 // that we do not remove thread without safepoint code notice
3894 { MutexLocker ml(Threads_lock);
3896 assert(includes(p), "p must be present");
3898 JavaThread* current = _thread_list;
3899 JavaThread* prev = NULL;
3901 while (current != p) {
3902 prev = current;
3903 current = current->next();
3904 }
3906 if (prev) {
3907 prev->set_next(current->next());
3908 } else {
3909 _thread_list = p->next();
3910 }
3911 _number_of_threads--;
3912 oop threadObj = p->threadObj();
3913 bool daemon = true;
3914 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
3915 _number_of_non_daemon_threads--;
3916 daemon = false;
3918 // Only one thread left, do a notify on the Threads_lock so a thread waiting
3919 // on destroy_vm will wake up.
3920 if (number_of_non_daemon_threads() == 1)
3921 Threads_lock->notify_all();
3922 }
3923 ThreadService::remove_thread(p, daemon);
3925 // Make sure that safepoint code disregard this thread. This is needed since
3926 // the thread might mess around with locks after this point. This can cause it
3927 // to do callbacks into the safepoint code. However, the safepoint code is not aware
3928 // of this thread since it is removed from the queue.
3929 p->set_terminated_value();
3930 } // unlock Threads_lock
3932 // Since Events::log uses a lock, we grab it outside the Threads_lock
3933 Events::log("Thread exited: " INTPTR_FORMAT, p);
3934 }
3936 // Threads_lock must be held when this is called (or must be called during a safepoint)
3937 bool Threads::includes(JavaThread* p) {
3938 assert(Threads_lock->is_locked(), "sanity check");
3939 ALL_JAVA_THREADS(q) {
3940 if (q == p ) {
3941 return true;
3942 }
3943 }
3944 return false;
3945 }
3947 // Operations on the Threads list for GC. These are not explicitly locked,
3948 // but the garbage collector must provide a safe context for them to run.
3949 // In particular, these things should never be called when the Threads_lock
3950 // is held by some other thread. (Note: the Safepoint abstraction also
3951 // uses the Threads_lock to gurantee this property. It also makes sure that
3952 // all threads gets blocked when exiting or starting).
3954 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3955 ALL_JAVA_THREADS(p) {
3956 p->oops_do(f, cf);
3957 }
3958 VMThread::vm_thread()->oops_do(f, cf);
3959 }
3961 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) {
3962 // Introduce a mechanism allowing parallel threads to claim threads as
3963 // root groups. Overhead should be small enough to use all the time,
3964 // even in sequential code.
3965 SharedHeap* sh = SharedHeap::heap();
3966 // Cannot yet substitute active_workers for n_par_threads
3967 // because of G1CollectedHeap::verify() use of
3968 // SharedHeap::process_strong_roots(). n_par_threads == 0 will
3969 // turn off parallelism in process_strong_roots while active_workers
3970 // is being used for parallelism elsewhere.
3971 bool is_par = sh->n_par_threads() > 0;
3972 assert(!is_par ||
3973 (SharedHeap::heap()->n_par_threads() ==
3974 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
3975 int cp = SharedHeap::heap()->strong_roots_parity();
3976 ALL_JAVA_THREADS(p) {
3977 if (p->claim_oops_do(is_par, cp)) {
3978 p->oops_do(f, cf);
3979 }
3980 }
3981 VMThread* vmt = VMThread::vm_thread();
3982 if (vmt->claim_oops_do(is_par, cp)) {
3983 vmt->oops_do(f, cf);
3984 }
3985 }
3987 #ifndef SERIALGC
3988 // Used by ParallelScavenge
3989 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
3990 ALL_JAVA_THREADS(p) {
3991 q->enqueue(new ThreadRootsTask(p));
3992 }
3993 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
3994 }
3996 // Used by Parallel Old
3997 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
3998 ALL_JAVA_THREADS(p) {
3999 q->enqueue(new ThreadRootsMarkingTask(p));
4000 }
4001 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4002 }
4003 #endif // SERIALGC
4005 void Threads::nmethods_do(CodeBlobClosure* cf) {
4006 ALL_JAVA_THREADS(p) {
4007 p->nmethods_do(cf);
4008 }
4009 VMThread::vm_thread()->nmethods_do(cf);
4010 }
4012 void Threads::gc_epilogue() {
4013 ALL_JAVA_THREADS(p) {
4014 p->gc_epilogue();
4015 }
4016 }
4018 void Threads::gc_prologue() {
4019 ALL_JAVA_THREADS(p) {
4020 p->gc_prologue();
4021 }
4022 }
4024 void Threads::deoptimized_wrt_marked_nmethods() {
4025 ALL_JAVA_THREADS(p) {
4026 p->deoptimized_wrt_marked_nmethods();
4027 }
4028 }
4031 // Get count Java threads that are waiting to enter the specified monitor.
4032 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4033 address monitor, bool doLock) {
4034 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4035 "must grab Threads_lock or be at safepoint");
4036 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4038 int i = 0;
4039 {
4040 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4041 ALL_JAVA_THREADS(p) {
4042 if (p->is_Compiler_thread()) continue;
4044 address pending = (address)p->current_pending_monitor();
4045 if (pending == monitor) { // found a match
4046 if (i < count) result->append(p); // save the first count matches
4047 i++;
4048 }
4049 }
4050 }
4051 return result;
4052 }
4055 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4056 assert(doLock ||
4057 Threads_lock->owned_by_self() ||
4058 SafepointSynchronize::is_at_safepoint(),
4059 "must grab Threads_lock or be at safepoint");
4061 // NULL owner means not locked so we can skip the search
4062 if (owner == NULL) return NULL;
4064 {
4065 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4066 ALL_JAVA_THREADS(p) {
4067 // first, see if owner is the address of a Java thread
4068 if (owner == (address)p) return p;
4069 }
4070 }
4071 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
4072 if (UseHeavyMonitors) return NULL;
4074 //
4075 // If we didn't find a matching Java thread and we didn't force use of
4076 // heavyweight monitors, then the owner is the stack address of the
4077 // Lock Word in the owning Java thread's stack.
4078 //
4079 JavaThread* the_owner = NULL;
4080 {
4081 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4082 ALL_JAVA_THREADS(q) {
4083 if (q->is_lock_owned(owner)) {
4084 the_owner = q;
4085 break;
4086 }
4087 }
4088 }
4089 assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
4090 return the_owner;
4091 }
4093 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4094 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4095 char buf[32];
4096 st->print_cr(os::local_time_string(buf, sizeof(buf)));
4098 st->print_cr("Full thread dump %s (%s %s):",
4099 Abstract_VM_Version::vm_name(),
4100 Abstract_VM_Version::vm_release(),
4101 Abstract_VM_Version::vm_info_string()
4102 );
4103 st->cr();
4105 #ifndef SERIALGC
4106 // Dump concurrent locks
4107 ConcurrentLocksDump concurrent_locks;
4108 if (print_concurrent_locks) {
4109 concurrent_locks.dump_at_safepoint();
4110 }
4111 #endif // SERIALGC
4113 ALL_JAVA_THREADS(p) {
4114 ResourceMark rm;
4115 p->print_on(st);
4116 if (print_stacks) {
4117 if (internal_format) {
4118 p->trace_stack();
4119 } else {
4120 p->print_stack_on(st);
4121 }
4122 }
4123 st->cr();
4124 #ifndef SERIALGC
4125 if (print_concurrent_locks) {
4126 concurrent_locks.print_locks_on(p, st);
4127 }
4128 #endif // SERIALGC
4129 }
4131 VMThread::vm_thread()->print_on(st);
4132 st->cr();
4133 Universe::heap()->print_gc_threads_on(st);
4134 WatcherThread* wt = WatcherThread::watcher_thread();
4135 if (wt != NULL) wt->print_on(st);
4136 st->cr();
4137 CompileBroker::print_compiler_threads_on(st);
4138 st->flush();
4139 }
4141 // Threads::print_on_error() is called by fatal error handler. It's possible
4142 // that VM is not at safepoint and/or current thread is inside signal handler.
4143 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4144 // memory (even in resource area), it might deadlock the error handler.
4145 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4146 bool found_current = false;
4147 st->print_cr("Java Threads: ( => current thread )");
4148 ALL_JAVA_THREADS(thread) {
4149 bool is_current = (current == thread);
4150 found_current = found_current || is_current;
4152 st->print("%s", is_current ? "=>" : " ");
4154 st->print(PTR_FORMAT, thread);
4155 st->print(" ");
4156 thread->print_on_error(st, buf, buflen);
4157 st->cr();
4158 }
4159 st->cr();
4161 st->print_cr("Other Threads:");
4162 if (VMThread::vm_thread()) {
4163 bool is_current = (current == VMThread::vm_thread());
4164 found_current = found_current || is_current;
4165 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4167 st->print(PTR_FORMAT, VMThread::vm_thread());
4168 st->print(" ");
4169 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4170 st->cr();
4171 }
4172 WatcherThread* wt = WatcherThread::watcher_thread();
4173 if (wt != NULL) {
4174 bool is_current = (current == wt);
4175 found_current = found_current || is_current;
4176 st->print("%s", is_current ? "=>" : " ");
4178 st->print(PTR_FORMAT, wt);
4179 st->print(" ");
4180 wt->print_on_error(st, buf, buflen);
4181 st->cr();
4182 }
4183 if (!found_current) {
4184 st->cr();
4185 st->print("=>" PTR_FORMAT " (exited) ", current);
4186 current->print_on_error(st, buf, buflen);
4187 st->cr();
4188 }
4189 }
4191 // Internal SpinLock and Mutex
4192 // Based on ParkEvent
4194 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4195 //
4196 // We employ SpinLocks _only for low-contention, fixed-length
4197 // short-duration critical sections where we're concerned
4198 // about native mutex_t or HotSpot Mutex:: latency.
4199 // The mux construct provides a spin-then-block mutual exclusion
4200 // mechanism.
4201 //
4202 // Testing has shown that contention on the ListLock guarding gFreeList
4203 // is common. If we implement ListLock as a simple SpinLock it's common
4204 // for the JVM to devolve to yielding with little progress. This is true
4205 // despite the fact that the critical sections protected by ListLock are
4206 // extremely short.
4207 //
4208 // TODO-FIXME: ListLock should be of type SpinLock.
4209 // We should make this a 1st-class type, integrated into the lock
4210 // hierarchy as leaf-locks. Critically, the SpinLock structure
4211 // should have sufficient padding to avoid false-sharing and excessive
4212 // cache-coherency traffic.
4215 typedef volatile int SpinLockT ;
4217 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4218 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4219 return ; // normal fast-path return
4220 }
4222 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4223 TEVENT (SpinAcquire - ctx) ;
4224 int ctr = 0 ;
4225 int Yields = 0 ;
4226 for (;;) {
4227 while (*adr != 0) {
4228 ++ctr ;
4229 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4230 if (Yields > 5) {
4231 // Consider using a simple NakedSleep() instead.
4232 // Then SpinAcquire could be called by non-JVM threads
4233 Thread::current()->_ParkEvent->park(1) ;
4234 } else {
4235 os::NakedYield() ;
4236 ++Yields ;
4237 }
4238 } else {
4239 SpinPause() ;
4240 }
4241 }
4242 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4243 }
4244 }
4246 void Thread::SpinRelease (volatile int * adr) {
4247 assert (*adr != 0, "invariant") ;
4248 OrderAccess::fence() ; // guarantee at least release consistency.
4249 // Roach-motel semantics.
4250 // It's safe if subsequent LDs and STs float "up" into the critical section,
4251 // but prior LDs and STs within the critical section can't be allowed
4252 // to reorder or float past the ST that releases the lock.
4253 *adr = 0 ;
4254 }
4256 // muxAcquire and muxRelease:
4257 //
4258 // * muxAcquire and muxRelease support a single-word lock-word construct.
4259 // The LSB of the word is set IFF the lock is held.
4260 // The remainder of the word points to the head of a singly-linked list
4261 // of threads blocked on the lock.
4262 //
4263 // * The current implementation of muxAcquire-muxRelease uses its own
4264 // dedicated Thread._MuxEvent instance. If we're interested in
4265 // minimizing the peak number of extant ParkEvent instances then
4266 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4267 // as certain invariants were satisfied. Specifically, care would need
4268 // to be taken with regards to consuming unpark() "permits".
4269 // A safe rule of thumb is that a thread would never call muxAcquire()
4270 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4271 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4272 // consume an unpark() permit intended for monitorenter, for instance.
4273 // One way around this would be to widen the restricted-range semaphore
4274 // implemented in park(). Another alternative would be to provide
4275 // multiple instances of the PlatformEvent() for each thread. One
4276 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4277 //
4278 // * Usage:
4279 // -- Only as leaf locks
4280 // -- for short-term locking only as muxAcquire does not perform
4281 // thread state transitions.
4282 //
4283 // Alternatives:
4284 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4285 // but with parking or spin-then-park instead of pure spinning.
4286 // * Use Taura-Oyama-Yonenzawa locks.
4287 // * It's possible to construct a 1-0 lock if we encode the lockword as
4288 // (List,LockByte). Acquire will CAS the full lockword while Release
4289 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4290 // acquiring threads use timers (ParkTimed) to detect and recover from
4291 // the stranding window. Thread/Node structures must be aligned on 256-byte
4292 // boundaries by using placement-new.
4293 // * Augment MCS with advisory back-link fields maintained with CAS().
4294 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4295 // The validity of the backlinks must be ratified before we trust the value.
4296 // If the backlinks are invalid the exiting thread must back-track through the
4297 // the forward links, which are always trustworthy.
4298 // * Add a successor indication. The LockWord is currently encoded as
4299 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4300 // to provide the usual futile-wakeup optimization.
4301 // See RTStt for details.
4302 // * Consider schedctl.sc_nopreempt to cover the critical section.
4303 //
4306 typedef volatile intptr_t MutexT ; // Mux Lock-word
4307 enum MuxBits { LOCKBIT = 1 } ;
4309 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4310 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4311 if (w == 0) return ;
4312 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4313 return ;
4314 }
4316 TEVENT (muxAcquire - Contention) ;
4317 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4318 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4319 for (;;) {
4320 int its = (os::is_MP() ? 100 : 0) + 1 ;
4322 // Optional spin phase: spin-then-park strategy
4323 while (--its >= 0) {
4324 w = *Lock ;
4325 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4326 return ;
4327 }
4328 }
4330 Self->reset() ;
4331 Self->OnList = intptr_t(Lock) ;
4332 // The following fence() isn't _strictly necessary as the subsequent
4333 // CAS() both serializes execution and ratifies the fetched *Lock value.
4334 OrderAccess::fence();
4335 for (;;) {
4336 w = *Lock ;
4337 if ((w & LOCKBIT) == 0) {
4338 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4339 Self->OnList = 0 ; // hygiene - allows stronger asserts
4340 return ;
4341 }
4342 continue ; // Interference -- *Lock changed -- Just retry
4343 }
4344 assert (w & LOCKBIT, "invariant") ;
4345 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4346 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4347 }
4349 while (Self->OnList != 0) {
4350 Self->park() ;
4351 }
4352 }
4353 }
4355 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4356 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4357 if (w == 0) return ;
4358 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4359 return ;
4360 }
4362 TEVENT (muxAcquire - Contention) ;
4363 ParkEvent * ReleaseAfter = NULL ;
4364 if (ev == NULL) {
4365 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4366 }
4367 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4368 for (;;) {
4369 guarantee (ev->OnList == 0, "invariant") ;
4370 int its = (os::is_MP() ? 100 : 0) + 1 ;
4372 // Optional spin phase: spin-then-park strategy
4373 while (--its >= 0) {
4374 w = *Lock ;
4375 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4376 if (ReleaseAfter != NULL) {
4377 ParkEvent::Release (ReleaseAfter) ;
4378 }
4379 return ;
4380 }
4381 }
4383 ev->reset() ;
4384 ev->OnList = intptr_t(Lock) ;
4385 // The following fence() isn't _strictly necessary as the subsequent
4386 // CAS() both serializes execution and ratifies the fetched *Lock value.
4387 OrderAccess::fence();
4388 for (;;) {
4389 w = *Lock ;
4390 if ((w & LOCKBIT) == 0) {
4391 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4392 ev->OnList = 0 ;
4393 // We call ::Release while holding the outer lock, thus
4394 // artificially lengthening the critical section.
4395 // Consider deferring the ::Release() until the subsequent unlock(),
4396 // after we've dropped the outer lock.
4397 if (ReleaseAfter != NULL) {
4398 ParkEvent::Release (ReleaseAfter) ;
4399 }
4400 return ;
4401 }
4402 continue ; // Interference -- *Lock changed -- Just retry
4403 }
4404 assert (w & LOCKBIT, "invariant") ;
4405 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4406 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4407 }
4409 while (ev->OnList != 0) {
4410 ev->park() ;
4411 }
4412 }
4413 }
4415 // Release() must extract a successor from the list and then wake that thread.
4416 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4417 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4418 // Release() would :
4419 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4420 // (B) Extract a successor from the private list "in-hand"
4421 // (C) attempt to CAS() the residual back into *Lock over null.
4422 // If there were any newly arrived threads and the CAS() would fail.
4423 // In that case Release() would detach the RATs, re-merge the list in-hand
4424 // with the RATs and repeat as needed. Alternately, Release() might
4425 // detach and extract a successor, but then pass the residual list to the wakee.
4426 // The wakee would be responsible for reattaching and remerging before it
4427 // competed for the lock.
4428 //
4429 // Both "pop" and DMR are immune from ABA corruption -- there can be
4430 // multiple concurrent pushers, but only one popper or detacher.
4431 // This implementation pops from the head of the list. This is unfair,
4432 // but tends to provide excellent throughput as hot threads remain hot.
4433 // (We wake recently run threads first).
4435 void Thread::muxRelease (volatile intptr_t * Lock) {
4436 for (;;) {
4437 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4438 assert (w & LOCKBIT, "invariant") ;
4439 if (w == LOCKBIT) return ;
4440 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4441 assert (List != NULL, "invariant") ;
4442 assert (List->OnList == intptr_t(Lock), "invariant") ;
4443 ParkEvent * nxt = List->ListNext ;
4445 // The following CAS() releases the lock and pops the head element.
4446 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4447 continue ;
4448 }
4449 List->OnList = 0 ;
4450 OrderAccess::fence() ;
4451 List->unpark () ;
4452 return ;
4453 }
4454 }
4457 void Threads::verify() {
4458 ALL_JAVA_THREADS(p) {
4459 p->verify();
4460 }
4461 VMThread* thread = VMThread::vm_thread();
4462 if (thread != NULL) thread->verify();
4463 }