Tue, 08 Feb 2011 09:11:37 -0800
7017673: Remove setting of the sun.jkernel.DownloadManager as a boot classloader hook
Reviewed-by: alanb, dcubed, coleenp
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 "jvmtifiles/jvmtiEnv.hpp"
35 #include "memory/oopFactory.hpp"
36 #include "memory/universe.inline.hpp"
37 #include "oops/instanceKlass.hpp"
38 #include "oops/objArrayOop.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "oops/symbol.hpp"
41 #include "prims/jvm_misc.hpp"
42 #include "prims/jvmtiExport.hpp"
43 #include "prims/jvmtiThreadState.hpp"
44 #include "prims/privilegedStack.hpp"
45 #include "runtime/aprofiler.hpp"
46 #include "runtime/arguments.hpp"
47 #include "runtime/biasedLocking.hpp"
48 #include "runtime/deoptimization.hpp"
49 #include "runtime/fprofiler.hpp"
50 #include "runtime/frame.inline.hpp"
51 #include "runtime/init.hpp"
52 #include "runtime/interfaceSupport.hpp"
53 #include "runtime/java.hpp"
54 #include "runtime/javaCalls.hpp"
55 #include "runtime/jniPeriodicChecker.hpp"
56 #include "runtime/memprofiler.hpp"
57 #include "runtime/mutexLocker.hpp"
58 #include "runtime/objectMonitor.hpp"
59 #include "runtime/osThread.hpp"
60 #include "runtime/safepoint.hpp"
61 #include "runtime/sharedRuntime.hpp"
62 #include "runtime/statSampler.hpp"
63 #include "runtime/stubRoutines.hpp"
64 #include "runtime/task.hpp"
65 #include "runtime/threadCritical.hpp"
66 #include "runtime/threadLocalStorage.hpp"
67 #include "runtime/vframe.hpp"
68 #include "runtime/vframeArray.hpp"
69 #include "runtime/vframe_hp.hpp"
70 #include "runtime/vmThread.hpp"
71 #include "runtime/vm_operations.hpp"
72 #include "services/attachListener.hpp"
73 #include "services/management.hpp"
74 #include "services/threadService.hpp"
75 #include "utilities/defaultStream.hpp"
76 #include "utilities/dtrace.hpp"
77 #include "utilities/events.hpp"
78 #include "utilities/preserveException.hpp"
79 #ifdef TARGET_OS_FAMILY_linux
80 # include "os_linux.inline.hpp"
81 # include "thread_linux.inline.hpp"
82 #endif
83 #ifdef TARGET_OS_FAMILY_solaris
84 # include "os_solaris.inline.hpp"
85 # include "thread_solaris.inline.hpp"
86 #endif
87 #ifdef TARGET_OS_FAMILY_windows
88 # include "os_windows.inline.hpp"
89 # include "thread_windows.inline.hpp"
90 #endif
91 #ifndef SERIALGC
92 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
93 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
94 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
95 #endif
96 #ifdef COMPILER1
97 #include "c1/c1_Compiler.hpp"
98 #endif
99 #ifdef COMPILER2
100 #include "opto/c2compiler.hpp"
101 #include "opto/idealGraphPrinter.hpp"
102 #endif
104 #ifdef DTRACE_ENABLED
106 // Only bother with this argument setup if dtrace is available
108 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
109 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
110 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
111 intptr_t, intptr_t, bool);
112 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
113 intptr_t, intptr_t, bool);
115 #define DTRACE_THREAD_PROBE(probe, javathread) \
116 { \
117 ResourceMark rm(this); \
118 int len = 0; \
119 const char* name = (javathread)->get_thread_name(); \
120 len = strlen(name); \
121 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
122 name, len, \
123 java_lang_Thread::thread_id((javathread)->threadObj()), \
124 (javathread)->osthread()->thread_id(), \
125 java_lang_Thread::is_daemon((javathread)->threadObj())); \
126 }
128 #else // ndef DTRACE_ENABLED
130 #define DTRACE_THREAD_PROBE(probe, javathread)
132 #endif // ndef DTRACE_ENABLED
134 // Class hierarchy
135 // - Thread
136 // - VMThread
137 // - WatcherThread
138 // - ConcurrentMarkSweepThread
139 // - JavaThread
140 // - CompilerThread
142 // ======= Thread ========
144 // Support for forcing alignment of thread objects for biased locking
145 void* Thread::operator new(size_t size) {
146 if (UseBiasedLocking) {
147 const int alignment = markOopDesc::biased_lock_alignment;
148 size_t aligned_size = size + (alignment - sizeof(intptr_t));
149 void* real_malloc_addr = CHeapObj::operator new(aligned_size);
150 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
151 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
152 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
153 "JavaThread alignment code overflowed allocated storage");
154 if (TraceBiasedLocking) {
155 if (aligned_addr != real_malloc_addr)
156 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
157 real_malloc_addr, aligned_addr);
158 }
159 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
160 return aligned_addr;
161 } else {
162 return CHeapObj::operator new(size);
163 }
164 }
166 void Thread::operator delete(void* p) {
167 if (UseBiasedLocking) {
168 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
169 CHeapObj::operator delete(real_malloc_addr);
170 } else {
171 CHeapObj::operator delete(p);
172 }
173 }
176 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
177 // JavaThread
180 Thread::Thread() {
181 // stack and get_thread
182 set_stack_base(NULL);
183 set_stack_size(0);
184 set_self_raw_id(0);
185 set_lgrp_id(-1);
187 // allocated data structures
188 set_osthread(NULL);
189 set_resource_area(new ResourceArea());
190 set_handle_area(new HandleArea(NULL));
191 set_active_handles(NULL);
192 set_free_handle_block(NULL);
193 set_last_handle_mark(NULL);
195 // This initial value ==> never claimed.
196 _oops_do_parity = 0;
198 // the handle mark links itself to last_handle_mark
199 new HandleMark(this);
201 // plain initialization
202 debug_only(_owned_locks = NULL;)
203 debug_only(_allow_allocation_count = 0;)
204 NOT_PRODUCT(_allow_safepoint_count = 0;)
205 NOT_PRODUCT(_skip_gcalot = false;)
206 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
207 _jvmti_env_iteration_count = 0;
208 set_allocated_bytes(0);
209 _vm_operation_started_count = 0;
210 _vm_operation_completed_count = 0;
211 _current_pending_monitor = NULL;
212 _current_pending_monitor_is_from_java = true;
213 _current_waiting_monitor = NULL;
214 _num_nested_signal = 0;
215 omFreeList = NULL ;
216 omFreeCount = 0 ;
217 omFreeProvision = 32 ;
218 omInUseList = NULL ;
219 omInUseCount = 0 ;
221 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
222 _suspend_flags = 0;
224 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
225 _hashStateX = os::random() ;
226 _hashStateY = 842502087 ;
227 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
228 _hashStateW = 273326509 ;
230 _OnTrap = 0 ;
231 _schedctl = NULL ;
232 _Stalled = 0 ;
233 _TypeTag = 0x2BAD ;
235 // Many of the following fields are effectively final - immutable
236 // Note that nascent threads can't use the Native Monitor-Mutex
237 // construct until the _MutexEvent is initialized ...
238 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
239 // we might instead use a stack of ParkEvents that we could provision on-demand.
240 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
241 // and ::Release()
242 _ParkEvent = ParkEvent::Allocate (this) ;
243 _SleepEvent = ParkEvent::Allocate (this) ;
244 _MutexEvent = ParkEvent::Allocate (this) ;
245 _MuxEvent = ParkEvent::Allocate (this) ;
247 #ifdef CHECK_UNHANDLED_OOPS
248 if (CheckUnhandledOops) {
249 _unhandled_oops = new UnhandledOops(this);
250 }
251 #endif // CHECK_UNHANDLED_OOPS
252 #ifdef ASSERT
253 if (UseBiasedLocking) {
254 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
255 assert(this == _real_malloc_address ||
256 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
257 "bug in forced alignment of thread objects");
258 }
259 #endif /* ASSERT */
260 }
262 void Thread::initialize_thread_local_storage() {
263 // Note: Make sure this method only calls
264 // non-blocking operations. Otherwise, it might not work
265 // with the thread-startup/safepoint interaction.
267 // During Java thread startup, safepoint code should allow this
268 // method to complete because it may need to allocate memory to
269 // store information for the new thread.
271 // initialize structure dependent on thread local storage
272 ThreadLocalStorage::set_thread(this);
274 // set up any platform-specific state.
275 os::initialize_thread();
277 }
279 void Thread::record_stack_base_and_size() {
280 set_stack_base(os::current_stack_base());
281 set_stack_size(os::current_stack_size());
282 }
285 Thread::~Thread() {
286 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
287 ObjectSynchronizer::omFlush (this) ;
289 // deallocate data structures
290 delete resource_area();
291 // since the handle marks are using the handle area, we have to deallocated the root
292 // handle mark before deallocating the thread's handle area,
293 assert(last_handle_mark() != NULL, "check we have an element");
294 delete last_handle_mark();
295 assert(last_handle_mark() == NULL, "check we have reached the end");
297 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
298 // We NULL out the fields for good hygiene.
299 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
300 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
301 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
302 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
304 delete handle_area();
306 // osthread() can be NULL, if creation of thread failed.
307 if (osthread() != NULL) os::free_thread(osthread());
309 delete _SR_lock;
311 // clear thread local storage if the Thread is deleting itself
312 if (this == Thread::current()) {
313 ThreadLocalStorage::set_thread(NULL);
314 } else {
315 // In the case where we're not the current thread, invalidate all the
316 // caches in case some code tries to get the current thread or the
317 // thread that was destroyed, and gets stale information.
318 ThreadLocalStorage::invalidate_all();
319 }
320 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
321 }
323 // NOTE: dummy function for assertion purpose.
324 void Thread::run() {
325 ShouldNotReachHere();
326 }
328 #ifdef ASSERT
329 // Private method to check for dangling thread pointer
330 void check_for_dangling_thread_pointer(Thread *thread) {
331 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
332 "possibility of dangling Thread pointer");
333 }
334 #endif
337 #ifndef PRODUCT
338 // Tracing method for basic thread operations
339 void Thread::trace(const char* msg, const Thread* const thread) {
340 if (!TraceThreadEvents) return;
341 ResourceMark rm;
342 ThreadCritical tc;
343 const char *name = "non-Java thread";
344 int prio = -1;
345 if (thread->is_Java_thread()
346 && !thread->is_Compiler_thread()) {
347 // The Threads_lock must be held to get information about
348 // this thread but may not be in some situations when
349 // tracing thread events.
350 bool release_Threads_lock = false;
351 if (!Threads_lock->owned_by_self()) {
352 Threads_lock->lock();
353 release_Threads_lock = true;
354 }
355 JavaThread* jt = (JavaThread *)thread;
356 name = (char *)jt->get_thread_name();
357 oop thread_oop = jt->threadObj();
358 if (thread_oop != NULL) {
359 prio = java_lang_Thread::priority(thread_oop);
360 }
361 if (release_Threads_lock) {
362 Threads_lock->unlock();
363 }
364 }
365 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
366 }
367 #endif
370 ThreadPriority Thread::get_priority(const Thread* const thread) {
371 trace("get priority", thread);
372 ThreadPriority priority;
373 // Can return an error!
374 (void)os::get_priority(thread, priority);
375 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
376 return priority;
377 }
379 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
380 trace("set priority", thread);
381 debug_only(check_for_dangling_thread_pointer(thread);)
382 // Can return an error!
383 (void)os::set_priority(thread, priority);
384 }
387 void Thread::start(Thread* thread) {
388 trace("start", thread);
389 // Start is different from resume in that its safety is guaranteed by context or
390 // being called from a Java method synchronized on the Thread object.
391 if (!DisableStartThread) {
392 if (thread->is_Java_thread()) {
393 // Initialize the thread state to RUNNABLE before starting this thread.
394 // Can not set it after the thread started because we do not know the
395 // exact thread state at that time. It could be in MONITOR_WAIT or
396 // in SLEEPING or some other state.
397 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
398 java_lang_Thread::RUNNABLE);
399 }
400 os::start_thread(thread);
401 }
402 }
404 // Enqueue a VM_Operation to do the job for us - sometime later
405 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
406 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
407 VMThread::execute(vm_stop);
408 }
411 //
412 // Check if an external suspend request has completed (or has been
413 // cancelled). Returns true if the thread is externally suspended and
414 // false otherwise.
415 //
416 // The bits parameter returns information about the code path through
417 // the routine. Useful for debugging:
418 //
419 // set in is_ext_suspend_completed():
420 // 0x00000001 - routine was entered
421 // 0x00000010 - routine return false at end
422 // 0x00000100 - thread exited (return false)
423 // 0x00000200 - suspend request cancelled (return false)
424 // 0x00000400 - thread suspended (return true)
425 // 0x00001000 - thread is in a suspend equivalent state (return true)
426 // 0x00002000 - thread is native and walkable (return true)
427 // 0x00004000 - thread is native_trans and walkable (needed retry)
428 //
429 // set in wait_for_ext_suspend_completion():
430 // 0x00010000 - routine was entered
431 // 0x00020000 - suspend request cancelled before loop (return false)
432 // 0x00040000 - thread suspended before loop (return true)
433 // 0x00080000 - suspend request cancelled in loop (return false)
434 // 0x00100000 - thread suspended in loop (return true)
435 // 0x00200000 - suspend not completed during retry loop (return false)
436 //
438 // Helper class for tracing suspend wait debug bits.
439 //
440 // 0x00000100 indicates that the target thread exited before it could
441 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
442 // 0x00080000 each indicate a cancelled suspend request so they don't
443 // count as wait failures either.
444 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
446 class TraceSuspendDebugBits : public StackObj {
447 private:
448 JavaThread * jt;
449 bool is_wait;
450 bool called_by_wait; // meaningful when !is_wait
451 uint32_t * bits;
453 public:
454 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
455 uint32_t *_bits) {
456 jt = _jt;
457 is_wait = _is_wait;
458 called_by_wait = _called_by_wait;
459 bits = _bits;
460 }
462 ~TraceSuspendDebugBits() {
463 if (!is_wait) {
464 #if 1
465 // By default, don't trace bits for is_ext_suspend_completed() calls.
466 // That trace is very chatty.
467 return;
468 #else
469 if (!called_by_wait) {
470 // If tracing for is_ext_suspend_completed() is enabled, then only
471 // trace calls to it from wait_for_ext_suspend_completion()
472 return;
473 }
474 #endif
475 }
477 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
478 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
479 MutexLocker ml(Threads_lock); // needed for get_thread_name()
480 ResourceMark rm;
482 tty->print_cr(
483 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
484 jt->get_thread_name(), *bits);
486 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
487 }
488 }
489 }
490 };
491 #undef DEBUG_FALSE_BITS
494 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
495 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
497 bool did_trans_retry = false; // only do thread_in_native_trans retry once
498 bool do_trans_retry; // flag to force the retry
500 *bits |= 0x00000001;
502 do {
503 do_trans_retry = false;
505 if (is_exiting()) {
506 // Thread is in the process of exiting. This is always checked
507 // first to reduce the risk of dereferencing a freed JavaThread.
508 *bits |= 0x00000100;
509 return false;
510 }
512 if (!is_external_suspend()) {
513 // Suspend request is cancelled. This is always checked before
514 // is_ext_suspended() to reduce the risk of a rogue resume
515 // confusing the thread that made the suspend request.
516 *bits |= 0x00000200;
517 return false;
518 }
520 if (is_ext_suspended()) {
521 // thread is suspended
522 *bits |= 0x00000400;
523 return true;
524 }
526 // Now that we no longer do hard suspends of threads running
527 // native code, the target thread can be changing thread state
528 // while we are in this routine:
529 //
530 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
531 //
532 // We save a copy of the thread state as observed at this moment
533 // and make our decision about suspend completeness based on the
534 // copy. This closes the race where the thread state is seen as
535 // _thread_in_native_trans in the if-thread_blocked check, but is
536 // seen as _thread_blocked in if-thread_in_native_trans check.
537 JavaThreadState save_state = thread_state();
539 if (save_state == _thread_blocked && is_suspend_equivalent()) {
540 // If the thread's state is _thread_blocked and this blocking
541 // condition is known to be equivalent to a suspend, then we can
542 // consider the thread to be externally suspended. This means that
543 // the code that sets _thread_blocked has been modified to do
544 // self-suspension if the blocking condition releases. We also
545 // used to check for CONDVAR_WAIT here, but that is now covered by
546 // the _thread_blocked with self-suspension check.
547 //
548 // Return true since we wouldn't be here unless there was still an
549 // external suspend request.
550 *bits |= 0x00001000;
551 return true;
552 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
553 // Threads running native code will self-suspend on native==>VM/Java
554 // transitions. If its stack is walkable (should always be the case
555 // unless this function is called before the actual java_suspend()
556 // call), then the wait is done.
557 *bits |= 0x00002000;
558 return true;
559 } else if (!called_by_wait && !did_trans_retry &&
560 save_state == _thread_in_native_trans &&
561 frame_anchor()->walkable()) {
562 // The thread is transitioning from thread_in_native to another
563 // thread state. check_safepoint_and_suspend_for_native_trans()
564 // will force the thread to self-suspend. If it hasn't gotten
565 // there yet we may have caught the thread in-between the native
566 // code check above and the self-suspend. Lucky us. If we were
567 // called by wait_for_ext_suspend_completion(), then it
568 // will be doing the retries so we don't have to.
569 //
570 // Since we use the saved thread state in the if-statement above,
571 // there is a chance that the thread has already transitioned to
572 // _thread_blocked by the time we get here. In that case, we will
573 // make a single unnecessary pass through the logic below. This
574 // doesn't hurt anything since we still do the trans retry.
576 *bits |= 0x00004000;
578 // Once the thread leaves thread_in_native_trans for another
579 // thread state, we break out of this retry loop. We shouldn't
580 // need this flag to prevent us from getting back here, but
581 // sometimes paranoia is good.
582 did_trans_retry = true;
584 // We wait for the thread to transition to a more usable state.
585 for (int i = 1; i <= SuspendRetryCount; i++) {
586 // We used to do an "os::yield_all(i)" call here with the intention
587 // that yielding would increase on each retry. However, the parameter
588 // is ignored on Linux which means the yield didn't scale up. Waiting
589 // on the SR_lock below provides a much more predictable scale up for
590 // the delay. It also provides a simple/direct point to check for any
591 // safepoint requests from the VMThread
593 // temporarily drops SR_lock while doing wait with safepoint check
594 // (if we're a JavaThread - the WatcherThread can also call this)
595 // and increase delay with each retry
596 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
598 // check the actual thread state instead of what we saved above
599 if (thread_state() != _thread_in_native_trans) {
600 // the thread has transitioned to another thread state so
601 // try all the checks (except this one) one more time.
602 do_trans_retry = true;
603 break;
604 }
605 } // end retry loop
608 }
609 } while (do_trans_retry);
611 *bits |= 0x00000010;
612 return false;
613 }
615 //
616 // Wait for an external suspend request to complete (or be cancelled).
617 // Returns true if the thread is externally suspended and false otherwise.
618 //
619 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
620 uint32_t *bits) {
621 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
622 false /* !called_by_wait */, bits);
624 // local flag copies to minimize SR_lock hold time
625 bool is_suspended;
626 bool pending;
627 uint32_t reset_bits;
629 // set a marker so is_ext_suspend_completed() knows we are the caller
630 *bits |= 0x00010000;
632 // We use reset_bits to reinitialize the bits value at the top of
633 // each retry loop. This allows the caller to make use of any
634 // unused bits for their own marking purposes.
635 reset_bits = *bits;
637 {
638 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
639 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
640 delay, bits);
641 pending = is_external_suspend();
642 }
643 // must release SR_lock to allow suspension to complete
645 if (!pending) {
646 // A cancelled suspend request is the only false return from
647 // is_ext_suspend_completed() that keeps us from entering the
648 // retry loop.
649 *bits |= 0x00020000;
650 return false;
651 }
653 if (is_suspended) {
654 *bits |= 0x00040000;
655 return true;
656 }
658 for (int i = 1; i <= retries; i++) {
659 *bits = reset_bits; // reinit to only track last retry
661 // We used to do an "os::yield_all(i)" call here with the intention
662 // that yielding would increase on each retry. However, the parameter
663 // is ignored on Linux which means the yield didn't scale up. Waiting
664 // on the SR_lock below provides a much more predictable scale up for
665 // the delay. It also provides a simple/direct point to check for any
666 // safepoint requests from the VMThread
668 {
669 MutexLocker ml(SR_lock());
670 // wait with safepoint check (if we're a JavaThread - the WatcherThread
671 // can also call this) and increase delay with each retry
672 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
674 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
675 delay, bits);
677 // It is possible for the external suspend request to be cancelled
678 // (by a resume) before the actual suspend operation is completed.
679 // Refresh our local copy to see if we still need to wait.
680 pending = is_external_suspend();
681 }
683 if (!pending) {
684 // A cancelled suspend request is the only false return from
685 // is_ext_suspend_completed() that keeps us from staying in the
686 // retry loop.
687 *bits |= 0x00080000;
688 return false;
689 }
691 if (is_suspended) {
692 *bits |= 0x00100000;
693 return true;
694 }
695 } // end retry loop
697 // thread did not suspend after all our retries
698 *bits |= 0x00200000;
699 return false;
700 }
702 #ifndef PRODUCT
703 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
705 // This should not need to be atomic as the only way for simultaneous
706 // updates is via interrupts. Even then this should be rare or non-existant
707 // and we don't care that much anyway.
709 int index = _jmp_ring_index;
710 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
711 _jmp_ring[index]._target = (intptr_t) target;
712 _jmp_ring[index]._instruction = (intptr_t) instr;
713 _jmp_ring[index]._file = file;
714 _jmp_ring[index]._line = line;
715 }
716 #endif /* PRODUCT */
718 // Called by flat profiler
719 // Callers have already called wait_for_ext_suspend_completion
720 // The assertion for that is currently too complex to put here:
721 bool JavaThread::profile_last_Java_frame(frame* _fr) {
722 bool gotframe = false;
723 // self suspension saves needed state.
724 if (has_last_Java_frame() && _anchor.walkable()) {
725 *_fr = pd_last_frame();
726 gotframe = true;
727 }
728 return gotframe;
729 }
731 void Thread::interrupt(Thread* thread) {
732 trace("interrupt", thread);
733 debug_only(check_for_dangling_thread_pointer(thread);)
734 os::interrupt(thread);
735 }
737 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
738 trace("is_interrupted", thread);
739 debug_only(check_for_dangling_thread_pointer(thread);)
740 // Note: If clear_interrupted==false, this simply fetches and
741 // returns the value of the field osthread()->interrupted().
742 return os::is_interrupted(thread, clear_interrupted);
743 }
746 // GC Support
747 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
748 jint thread_parity = _oops_do_parity;
749 if (thread_parity != strong_roots_parity) {
750 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
751 if (res == thread_parity) return true;
752 else {
753 guarantee(res == strong_roots_parity, "Or else what?");
754 assert(SharedHeap::heap()->n_par_threads() > 0,
755 "Should only fail when parallel.");
756 return false;
757 }
758 }
759 assert(SharedHeap::heap()->n_par_threads() > 0,
760 "Should only fail when parallel.");
761 return false;
762 }
764 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
765 active_handles()->oops_do(f);
766 // Do oop for ThreadShadow
767 f->do_oop((oop*)&_pending_exception);
768 handle_area()->oops_do(f);
769 }
771 void Thread::nmethods_do(CodeBlobClosure* cf) {
772 // no nmethods in a generic thread...
773 }
775 void Thread::print_on(outputStream* st) const {
776 // get_priority assumes osthread initialized
777 if (osthread() != NULL) {
778 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
779 osthread()->print_on(st);
780 }
781 debug_only(if (WizardMode) print_owned_locks_on(st);)
782 }
784 // Thread::print_on_error() is called by fatal error handler. Don't use
785 // any lock or allocate memory.
786 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
787 if (is_VM_thread()) st->print("VMThread");
788 else if (is_Compiler_thread()) st->print("CompilerThread");
789 else if (is_Java_thread()) st->print("JavaThread");
790 else if (is_GC_task_thread()) st->print("GCTaskThread");
791 else if (is_Watcher_thread()) st->print("WatcherThread");
792 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
793 else st->print("Thread");
795 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
796 _stack_base - _stack_size, _stack_base);
798 if (osthread()) {
799 st->print(" [id=%d]", osthread()->thread_id());
800 }
801 }
803 #ifdef ASSERT
804 void Thread::print_owned_locks_on(outputStream* st) const {
805 Monitor *cur = _owned_locks;
806 if (cur == NULL) {
807 st->print(" (no locks) ");
808 } else {
809 st->print_cr(" Locks owned:");
810 while(cur) {
811 cur->print_on(st);
812 cur = cur->next();
813 }
814 }
815 }
817 static int ref_use_count = 0;
819 bool Thread::owns_locks_but_compiled_lock() const {
820 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
821 if (cur != Compile_lock) return true;
822 }
823 return false;
824 }
827 #endif
829 #ifndef PRODUCT
831 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
832 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
833 // no threads which allow_vm_block's are held
834 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
835 // Check if current thread is allowed to block at a safepoint
836 if (!(_allow_safepoint_count == 0))
837 fatal("Possible safepoint reached by thread that does not allow it");
838 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
839 fatal("LEAF method calling lock?");
840 }
842 #ifdef ASSERT
843 if (potential_vm_operation && is_Java_thread()
844 && !Universe::is_bootstrapping()) {
845 // Make sure we do not hold any locks that the VM thread also uses.
846 // This could potentially lead to deadlocks
847 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
848 // Threads_lock is special, since the safepoint synchronization will not start before this is
849 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
850 // since it is used to transfer control between JavaThreads and the VMThread
851 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
852 if ( (cur->allow_vm_block() &&
853 cur != Threads_lock &&
854 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
855 cur != VMOperationRequest_lock &&
856 cur != VMOperationQueue_lock) ||
857 cur->rank() == Mutex::special) {
858 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
859 }
860 }
861 }
863 if (GCALotAtAllSafepoints) {
864 // We could enter a safepoint here and thus have a gc
865 InterfaceSupport::check_gc_alot();
866 }
867 #endif
868 }
869 #endif
871 bool Thread::is_in_stack(address adr) const {
872 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
873 address end = os::current_stack_pointer();
874 if (stack_base() >= adr && adr >= end) return true;
876 return false;
877 }
880 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
881 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
882 // used for compilation in the future. If that change is made, the need for these methods
883 // should be revisited, and they should be removed if possible.
885 bool Thread::is_lock_owned(address adr) const {
886 return on_local_stack(adr);
887 }
889 bool Thread::set_as_starting_thread() {
890 // NOTE: this must be called inside the main thread.
891 return os::create_main_thread((JavaThread*)this);
892 }
894 static void initialize_class(Symbol* class_name, TRAPS) {
895 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
896 instanceKlass::cast(klass)->initialize(CHECK);
897 }
900 // Creates the initial ThreadGroup
901 static Handle create_initial_thread_group(TRAPS) {
902 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
903 instanceKlassHandle klass (THREAD, k);
905 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
906 {
907 JavaValue result(T_VOID);
908 JavaCalls::call_special(&result,
909 system_instance,
910 klass,
911 vmSymbols::object_initializer_name(),
912 vmSymbols::void_method_signature(),
913 CHECK_NH);
914 }
915 Universe::set_system_thread_group(system_instance());
917 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
918 {
919 JavaValue result(T_VOID);
920 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
921 JavaCalls::call_special(&result,
922 main_instance,
923 klass,
924 vmSymbols::object_initializer_name(),
925 vmSymbols::threadgroup_string_void_signature(),
926 system_instance,
927 string,
928 CHECK_NH);
929 }
930 return main_instance;
931 }
933 // Creates the initial Thread
934 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
935 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
936 instanceKlassHandle klass (THREAD, k);
937 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
939 java_lang_Thread::set_thread(thread_oop(), thread);
940 java_lang_Thread::set_priority(thread_oop(), NormPriority);
941 thread->set_threadObj(thread_oop());
943 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
945 JavaValue result(T_VOID);
946 JavaCalls::call_special(&result, thread_oop,
947 klass,
948 vmSymbols::object_initializer_name(),
949 vmSymbols::threadgroup_string_void_signature(),
950 thread_group,
951 string,
952 CHECK_NULL);
953 return thread_oop();
954 }
956 static void call_initializeSystemClass(TRAPS) {
957 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
958 instanceKlassHandle klass (THREAD, k);
960 JavaValue result(T_VOID);
961 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
962 vmSymbols::void_method_signature(), CHECK);
963 }
965 // General purpose hook into Java code, run once when the VM is initialized.
966 // The Java library method itself may be changed independently from the VM.
967 static void call_postVMInitHook(TRAPS) {
968 klassOop k = SystemDictionary::sun_misc_PostVMInitHook_klass();
969 instanceKlassHandle klass (THREAD, k);
970 if (klass.not_null()) {
971 JavaValue result(T_VOID);
972 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
973 vmSymbols::void_method_signature(),
974 CHECK);
975 }
976 }
978 static void reset_vm_info_property(TRAPS) {
979 // the vm info string
980 ResourceMark rm(THREAD);
981 const char *vm_info = VM_Version::vm_info_string();
983 // java.lang.System class
984 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
985 instanceKlassHandle klass (THREAD, k);
987 // setProperty arguments
988 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
989 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
991 // return value
992 JavaValue r(T_OBJECT);
994 // public static String setProperty(String key, String value);
995 JavaCalls::call_static(&r,
996 klass,
997 vmSymbols::setProperty_name(),
998 vmSymbols::string_string_string_signature(),
999 key_str,
1000 value_str,
1001 CHECK);
1002 }
1005 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1006 assert(thread_group.not_null(), "thread group should be specified");
1007 assert(threadObj() == NULL, "should only create Java thread object once");
1009 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1010 instanceKlassHandle klass (THREAD, k);
1011 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1013 java_lang_Thread::set_thread(thread_oop(), this);
1014 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1015 set_threadObj(thread_oop());
1017 JavaValue result(T_VOID);
1018 if (thread_name != NULL) {
1019 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1020 // Thread gets assigned specified name and null target
1021 JavaCalls::call_special(&result,
1022 thread_oop,
1023 klass,
1024 vmSymbols::object_initializer_name(),
1025 vmSymbols::threadgroup_string_void_signature(),
1026 thread_group, // Argument 1
1027 name, // Argument 2
1028 THREAD);
1029 } else {
1030 // Thread gets assigned name "Thread-nnn" and null target
1031 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1032 JavaCalls::call_special(&result,
1033 thread_oop,
1034 klass,
1035 vmSymbols::object_initializer_name(),
1036 vmSymbols::threadgroup_runnable_void_signature(),
1037 thread_group, // Argument 1
1038 Handle(), // Argument 2
1039 THREAD);
1040 }
1043 if (daemon) {
1044 java_lang_Thread::set_daemon(thread_oop());
1045 }
1047 if (HAS_PENDING_EXCEPTION) {
1048 return;
1049 }
1051 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1052 Handle threadObj(this, this->threadObj());
1054 JavaCalls::call_special(&result,
1055 thread_group,
1056 group,
1057 vmSymbols::add_method_name(),
1058 vmSymbols::thread_void_signature(),
1059 threadObj, // Arg 1
1060 THREAD);
1063 }
1065 // NamedThread -- non-JavaThread subclasses with multiple
1066 // uniquely named instances should derive from this.
1067 NamedThread::NamedThread() : Thread() {
1068 _name = NULL;
1069 _processed_thread = NULL;
1070 }
1072 NamedThread::~NamedThread() {
1073 if (_name != NULL) {
1074 FREE_C_HEAP_ARRAY(char, _name);
1075 _name = NULL;
1076 }
1077 }
1079 void NamedThread::set_name(const char* format, ...) {
1080 guarantee(_name == NULL, "Only get to set name once.");
1081 _name = NEW_C_HEAP_ARRAY(char, max_name_len);
1082 guarantee(_name != NULL, "alloc failure");
1083 va_list ap;
1084 va_start(ap, format);
1085 jio_vsnprintf(_name, max_name_len, format, ap);
1086 va_end(ap);
1087 }
1089 // ======= WatcherThread ========
1091 // The watcher thread exists to simulate timer interrupts. It should
1092 // be replaced by an abstraction over whatever native support for
1093 // timer interrupts exists on the platform.
1095 WatcherThread* WatcherThread::_watcher_thread = NULL;
1096 volatile bool WatcherThread::_should_terminate = false;
1098 WatcherThread::WatcherThread() : Thread() {
1099 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1100 if (os::create_thread(this, os::watcher_thread)) {
1101 _watcher_thread = this;
1103 // Set the watcher thread to the highest OS priority which should not be
1104 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1105 // is created. The only normal thread using this priority is the reference
1106 // handler thread, which runs for very short intervals only.
1107 // If the VMThread's priority is not lower than the WatcherThread profiling
1108 // will be inaccurate.
1109 os::set_priority(this, MaxPriority);
1110 if (!DisableStartThread) {
1111 os::start_thread(this);
1112 }
1113 }
1114 }
1116 void WatcherThread::run() {
1117 assert(this == watcher_thread(), "just checking");
1119 this->record_stack_base_and_size();
1120 this->initialize_thread_local_storage();
1121 this->set_active_handles(JNIHandleBlock::allocate_block());
1122 while(!_should_terminate) {
1123 assert(watcher_thread() == Thread::current(), "thread consistency check");
1124 assert(watcher_thread() == this, "thread consistency check");
1126 // Calculate how long it'll be until the next PeriodicTask work
1127 // should be done, and sleep that amount of time.
1128 size_t time_to_wait = PeriodicTask::time_to_wait();
1130 // we expect this to timeout - we only ever get unparked when
1131 // we should terminate
1132 {
1133 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1135 jlong prev_time = os::javaTimeNanos();
1136 for (;;) {
1137 int res= _SleepEvent->park(time_to_wait);
1138 if (res == OS_TIMEOUT || _should_terminate)
1139 break;
1140 // spurious wakeup of some kind
1141 jlong now = os::javaTimeNanos();
1142 time_to_wait -= (now - prev_time) / 1000000;
1143 if (time_to_wait <= 0)
1144 break;
1145 prev_time = now;
1146 }
1147 }
1149 if (is_error_reported()) {
1150 // A fatal error has happened, the error handler(VMError::report_and_die)
1151 // should abort JVM after creating an error log file. However in some
1152 // rare cases, the error handler itself might deadlock. Here we try to
1153 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1154 //
1155 // This code is in WatcherThread because WatcherThread wakes up
1156 // periodically so the fatal error handler doesn't need to do anything;
1157 // also because the WatcherThread is less likely to crash than other
1158 // threads.
1160 for (;;) {
1161 if (!ShowMessageBoxOnError
1162 && (OnError == NULL || OnError[0] == '\0')
1163 && Arguments::abort_hook() == NULL) {
1164 os::sleep(this, 2 * 60 * 1000, false);
1165 fdStream err(defaultStream::output_fd());
1166 err.print_raw_cr("# [ timer expired, abort... ]");
1167 // skip atexit/vm_exit/vm_abort hooks
1168 os::die();
1169 }
1171 // Wake up 5 seconds later, the fatal handler may reset OnError or
1172 // ShowMessageBoxOnError when it is ready to abort.
1173 os::sleep(this, 5 * 1000, false);
1174 }
1175 }
1177 PeriodicTask::real_time_tick(time_to_wait);
1179 // If we have no more tasks left due to dynamic disenrollment,
1180 // shut down the thread since we don't currently support dynamic enrollment
1181 if (PeriodicTask::num_tasks() == 0) {
1182 _should_terminate = true;
1183 }
1184 }
1186 // Signal that it is terminated
1187 {
1188 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1189 _watcher_thread = NULL;
1190 Terminator_lock->notify();
1191 }
1193 // Thread destructor usually does this..
1194 ThreadLocalStorage::set_thread(NULL);
1195 }
1197 void WatcherThread::start() {
1198 if (watcher_thread() == NULL) {
1199 _should_terminate = false;
1200 // Create the single instance of WatcherThread
1201 new WatcherThread();
1202 }
1203 }
1205 void WatcherThread::stop() {
1206 // it is ok to take late safepoints here, if needed
1207 MutexLocker mu(Terminator_lock);
1208 _should_terminate = true;
1209 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1211 Thread* watcher = watcher_thread();
1212 if (watcher != NULL)
1213 watcher->_SleepEvent->unpark();
1215 while(watcher_thread() != NULL) {
1216 // This wait should make safepoint checks, wait without a timeout,
1217 // and wait as a suspend-equivalent condition.
1218 //
1219 // Note: If the FlatProfiler is running, then this thread is waiting
1220 // for the WatcherThread to terminate and the WatcherThread, via the
1221 // FlatProfiler task, is waiting for the external suspend request on
1222 // this thread to complete. wait_for_ext_suspend_completion() will
1223 // eventually timeout, but that takes time. Making this wait a
1224 // suspend-equivalent condition solves that timeout problem.
1225 //
1226 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1227 Mutex::_as_suspend_equivalent_flag);
1228 }
1229 }
1231 void WatcherThread::print_on(outputStream* st) const {
1232 st->print("\"%s\" ", name());
1233 Thread::print_on(st);
1234 st->cr();
1235 }
1237 // ======= JavaThread ========
1239 // A JavaThread is a normal Java thread
1241 void JavaThread::initialize() {
1242 // Initialize fields
1244 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1245 set_claimed_par_id(-1);
1247 set_saved_exception_pc(NULL);
1248 set_threadObj(NULL);
1249 _anchor.clear();
1250 set_entry_point(NULL);
1251 set_jni_functions(jni_functions());
1252 set_callee_target(NULL);
1253 set_vm_result(NULL);
1254 set_vm_result_2(NULL);
1255 set_vframe_array_head(NULL);
1256 set_vframe_array_last(NULL);
1257 set_deferred_locals(NULL);
1258 set_deopt_mark(NULL);
1259 set_deopt_nmethod(NULL);
1260 clear_must_deopt_id();
1261 set_monitor_chunks(NULL);
1262 set_next(NULL);
1263 set_thread_state(_thread_new);
1264 _terminated = _not_terminated;
1265 _privileged_stack_top = NULL;
1266 _array_for_gc = NULL;
1267 _suspend_equivalent = false;
1268 _in_deopt_handler = 0;
1269 _doing_unsafe_access = false;
1270 _stack_guard_state = stack_guard_unused;
1271 _exception_oop = NULL;
1272 _exception_pc = 0;
1273 _exception_handler_pc = 0;
1274 _exception_stack_size = 0;
1275 _is_method_handle_return = 0;
1276 _jvmti_thread_state= NULL;
1277 _should_post_on_exceptions_flag = JNI_FALSE;
1278 _jvmti_get_loaded_classes_closure = NULL;
1279 _interp_only_mode = 0;
1280 _special_runtime_exit_condition = _no_async_condition;
1281 _pending_async_exception = NULL;
1282 _is_compiling = false;
1283 _thread_stat = NULL;
1284 _thread_stat = new ThreadStatistics();
1285 _blocked_on_compilation = false;
1286 _jni_active_critical = 0;
1287 _do_not_unlock_if_synchronized = false;
1288 _cached_monitor_info = NULL;
1289 _parker = Parker::Allocate(this) ;
1291 #ifndef PRODUCT
1292 _jmp_ring_index = 0;
1293 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1294 record_jump(NULL, NULL, NULL, 0);
1295 }
1296 #endif /* PRODUCT */
1298 set_thread_profiler(NULL);
1299 if (FlatProfiler::is_active()) {
1300 // This is where we would decide to either give each thread it's own profiler
1301 // or use one global one from FlatProfiler,
1302 // or up to some count of the number of profiled threads, etc.
1303 ThreadProfiler* pp = new ThreadProfiler();
1304 pp->engage();
1305 set_thread_profiler(pp);
1306 }
1308 // Setup safepoint state info for this thread
1309 ThreadSafepointState::create(this);
1311 debug_only(_java_call_counter = 0);
1313 // JVMTI PopFrame support
1314 _popframe_condition = popframe_inactive;
1315 _popframe_preserved_args = NULL;
1316 _popframe_preserved_args_size = 0;
1318 pd_initialize();
1319 }
1321 #ifndef SERIALGC
1322 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1323 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1324 #endif // !SERIALGC
1326 JavaThread::JavaThread(bool is_attaching) :
1327 Thread()
1328 #ifndef SERIALGC
1329 , _satb_mark_queue(&_satb_mark_queue_set),
1330 _dirty_card_queue(&_dirty_card_queue_set)
1331 #endif // !SERIALGC
1332 {
1333 initialize();
1334 _is_attaching = is_attaching;
1335 assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor");
1336 }
1338 bool JavaThread::reguard_stack(address cur_sp) {
1339 if (_stack_guard_state != stack_guard_yellow_disabled) {
1340 return true; // Stack already guarded or guard pages not needed.
1341 }
1343 if (register_stack_overflow()) {
1344 // For those architectures which have separate register and
1345 // memory stacks, we must check the register stack to see if
1346 // it has overflowed.
1347 return false;
1348 }
1350 // Java code never executes within the yellow zone: the latter is only
1351 // there to provoke an exception during stack banging. If java code
1352 // is executing there, either StackShadowPages should be larger, or
1353 // some exception code in c1, c2 or the interpreter isn't unwinding
1354 // when it should.
1355 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1357 enable_stack_yellow_zone();
1358 return true;
1359 }
1361 bool JavaThread::reguard_stack(void) {
1362 return reguard_stack(os::current_stack_pointer());
1363 }
1366 void JavaThread::block_if_vm_exited() {
1367 if (_terminated == _vm_exited) {
1368 // _vm_exited is set at safepoint, and Threads_lock is never released
1369 // we will block here forever
1370 Threads_lock->lock_without_safepoint_check();
1371 ShouldNotReachHere();
1372 }
1373 }
1376 // Remove this ifdef when C1 is ported to the compiler interface.
1377 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1379 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1380 Thread()
1381 #ifndef SERIALGC
1382 , _satb_mark_queue(&_satb_mark_queue_set),
1383 _dirty_card_queue(&_dirty_card_queue_set)
1384 #endif // !SERIALGC
1385 {
1386 if (TraceThreadEvents) {
1387 tty->print_cr("creating thread %p", this);
1388 }
1389 initialize();
1390 _is_attaching = false;
1391 set_entry_point(entry_point);
1392 // Create the native thread itself.
1393 // %note runtime_23
1394 os::ThreadType thr_type = os::java_thread;
1395 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1396 os::java_thread;
1397 os::create_thread(this, thr_type, stack_sz);
1399 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1400 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1401 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1402 // the exception consists of creating the exception object & initializing it, initialization
1403 // will leave the VM via a JavaCall and then all locks must be unlocked).
1404 //
1405 // The thread is still suspended when we reach here. Thread must be explicit started
1406 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1407 // by calling Threads:add. The reason why this is not done here, is because the thread
1408 // object must be fully initialized (take a look at JVM_Start)
1409 }
1411 JavaThread::~JavaThread() {
1412 if (TraceThreadEvents) {
1413 tty->print_cr("terminate thread %p", this);
1414 }
1416 // JSR166 -- return the parker to the free list
1417 Parker::Release(_parker);
1418 _parker = NULL ;
1420 // Free any remaining previous UnrollBlock
1421 vframeArray* old_array = vframe_array_last();
1423 if (old_array != NULL) {
1424 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1425 old_array->set_unroll_block(NULL);
1426 delete old_info;
1427 delete old_array;
1428 }
1430 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1431 if (deferred != NULL) {
1432 // This can only happen if thread is destroyed before deoptimization occurs.
1433 assert(deferred->length() != 0, "empty array!");
1434 do {
1435 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1436 deferred->remove_at(0);
1437 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1438 delete dlv;
1439 } while (deferred->length() != 0);
1440 delete deferred;
1441 }
1443 // All Java related clean up happens in exit
1444 ThreadSafepointState::destroy(this);
1445 if (_thread_profiler != NULL) delete _thread_profiler;
1446 if (_thread_stat != NULL) delete _thread_stat;
1447 }
1450 // The first routine called by a new Java thread
1451 void JavaThread::run() {
1452 // initialize thread-local alloc buffer related fields
1453 this->initialize_tlab();
1455 // used to test validitity of stack trace backs
1456 this->record_base_of_stack_pointer();
1458 // Record real stack base and size.
1459 this->record_stack_base_and_size();
1461 // Initialize thread local storage; set before calling MutexLocker
1462 this->initialize_thread_local_storage();
1464 this->create_stack_guard_pages();
1466 this->cache_global_variables();
1468 // Thread is now sufficient initialized to be handled by the safepoint code as being
1469 // in the VM. Change thread state from _thread_new to _thread_in_vm
1470 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1472 assert(JavaThread::current() == this, "sanity check");
1473 assert(!Thread::current()->owns_locks(), "sanity check");
1475 DTRACE_THREAD_PROBE(start, this);
1477 // This operation might block. We call that after all safepoint checks for a new thread has
1478 // been completed.
1479 this->set_active_handles(JNIHandleBlock::allocate_block());
1481 if (JvmtiExport::should_post_thread_life()) {
1482 JvmtiExport::post_thread_start(this);
1483 }
1485 // We call another function to do the rest so we are sure that the stack addresses used
1486 // from there will be lower than the stack base just computed
1487 thread_main_inner();
1489 // Note, thread is no longer valid at this point!
1490 }
1493 void JavaThread::thread_main_inner() {
1494 assert(JavaThread::current() == this, "sanity check");
1495 assert(this->threadObj() != NULL, "just checking");
1497 // Execute thread entry point unless this thread has a pending exception
1498 // or has been stopped before starting.
1499 // Note: Due to JVM_StopThread we can have pending exceptions already!
1500 if (!this->has_pending_exception() &&
1501 !java_lang_Thread::is_stillborn(this->threadObj())) {
1502 HandleMark hm(this);
1503 this->entry_point()(this, this);
1504 }
1506 DTRACE_THREAD_PROBE(stop, this);
1508 this->exit(false);
1509 delete this;
1510 }
1513 static void ensure_join(JavaThread* thread) {
1514 // We do not need to grap the Threads_lock, since we are operating on ourself.
1515 Handle threadObj(thread, thread->threadObj());
1516 assert(threadObj.not_null(), "java thread object must exist");
1517 ObjectLocker lock(threadObj, thread);
1518 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1519 thread->clear_pending_exception();
1520 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1521 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1522 // Clear the native thread instance - this makes isAlive return false and allows the join()
1523 // to complete once we've done the notify_all below
1524 java_lang_Thread::set_thread(threadObj(), NULL);
1525 lock.notify_all(thread);
1526 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1527 thread->clear_pending_exception();
1528 }
1531 // For any new cleanup additions, please check to see if they need to be applied to
1532 // cleanup_failed_attach_current_thread as well.
1533 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1534 assert(this == JavaThread::current(), "thread consistency check");
1535 if (!InitializeJavaLangSystem) return;
1537 HandleMark hm(this);
1538 Handle uncaught_exception(this, this->pending_exception());
1539 this->clear_pending_exception();
1540 Handle threadObj(this, this->threadObj());
1541 assert(threadObj.not_null(), "Java thread object should be created");
1543 if (get_thread_profiler() != NULL) {
1544 get_thread_profiler()->disengage();
1545 ResourceMark rm;
1546 get_thread_profiler()->print(get_thread_name());
1547 }
1550 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1551 {
1552 EXCEPTION_MARK;
1554 CLEAR_PENDING_EXCEPTION;
1555 }
1556 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1557 // has to be fixed by a runtime query method
1558 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1559 // JSR-166: change call from from ThreadGroup.uncaughtException to
1560 // java.lang.Thread.dispatchUncaughtException
1561 if (uncaught_exception.not_null()) {
1562 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1563 Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT",
1564 (address)uncaught_exception(), (address)threadObj(), (address)group());
1565 {
1566 EXCEPTION_MARK;
1567 // Check if the method Thread.dispatchUncaughtException() exists. If so
1568 // call it. Otherwise we have an older library without the JSR-166 changes,
1569 // so call ThreadGroup.uncaughtException()
1570 KlassHandle recvrKlass(THREAD, threadObj->klass());
1571 CallInfo callinfo;
1572 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1573 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1574 vmSymbols::dispatchUncaughtException_name(),
1575 vmSymbols::throwable_void_signature(),
1576 KlassHandle(), false, false, THREAD);
1577 CLEAR_PENDING_EXCEPTION;
1578 methodHandle method = callinfo.selected_method();
1579 if (method.not_null()) {
1580 JavaValue result(T_VOID);
1581 JavaCalls::call_virtual(&result,
1582 threadObj, thread_klass,
1583 vmSymbols::dispatchUncaughtException_name(),
1584 vmSymbols::throwable_void_signature(),
1585 uncaught_exception,
1586 THREAD);
1587 } else {
1588 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1589 JavaValue result(T_VOID);
1590 JavaCalls::call_virtual(&result,
1591 group, thread_group,
1592 vmSymbols::uncaughtException_name(),
1593 vmSymbols::thread_throwable_void_signature(),
1594 threadObj, // Arg 1
1595 uncaught_exception, // Arg 2
1596 THREAD);
1597 }
1598 CLEAR_PENDING_EXCEPTION;
1599 }
1600 }
1602 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1603 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1604 // is deprecated anyhow.
1605 { int count = 3;
1606 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1607 EXCEPTION_MARK;
1608 JavaValue result(T_VOID);
1609 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1610 JavaCalls::call_virtual(&result,
1611 threadObj, thread_klass,
1612 vmSymbols::exit_method_name(),
1613 vmSymbols::void_method_signature(),
1614 THREAD);
1615 CLEAR_PENDING_EXCEPTION;
1616 }
1617 }
1619 // notify JVMTI
1620 if (JvmtiExport::should_post_thread_life()) {
1621 JvmtiExport::post_thread_end(this);
1622 }
1624 // We have notified the agents that we are exiting, before we go on,
1625 // we must check for a pending external suspend request and honor it
1626 // in order to not surprise the thread that made the suspend request.
1627 while (true) {
1628 {
1629 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1630 if (!is_external_suspend()) {
1631 set_terminated(_thread_exiting);
1632 ThreadService::current_thread_exiting(this);
1633 break;
1634 }
1635 // Implied else:
1636 // Things get a little tricky here. We have a pending external
1637 // suspend request, but we are holding the SR_lock so we
1638 // can't just self-suspend. So we temporarily drop the lock
1639 // and then self-suspend.
1640 }
1642 ThreadBlockInVM tbivm(this);
1643 java_suspend_self();
1645 // We're done with this suspend request, but we have to loop around
1646 // and check again. Eventually we will get SR_lock without a pending
1647 // external suspend request and will be able to mark ourselves as
1648 // exiting.
1649 }
1650 // no more external suspends are allowed at this point
1651 } else {
1652 // before_exit() has already posted JVMTI THREAD_END events
1653 }
1655 // Notify waiters on thread object. This has to be done after exit() is called
1656 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1657 // group should have the destroyed bit set before waiters are notified).
1658 ensure_join(this);
1659 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1661 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1662 // held by this thread must be released. A detach operation must only
1663 // get here if there are no Java frames on the stack. Therefore, any
1664 // owned monitors at this point MUST be JNI-acquired monitors which are
1665 // pre-inflated and in the monitor cache.
1666 //
1667 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1668 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1669 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1670 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1671 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1672 }
1674 // These things needs to be done while we are still a Java Thread. Make sure that thread
1675 // is in a consistent state, in case GC happens
1676 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1678 if (active_handles() != NULL) {
1679 JNIHandleBlock* block = active_handles();
1680 set_active_handles(NULL);
1681 JNIHandleBlock::release_block(block);
1682 }
1684 if (free_handle_block() != NULL) {
1685 JNIHandleBlock* block = free_handle_block();
1686 set_free_handle_block(NULL);
1687 JNIHandleBlock::release_block(block);
1688 }
1690 // These have to be removed while this is still a valid thread.
1691 remove_stack_guard_pages();
1693 if (UseTLAB) {
1694 tlab().make_parsable(true); // retire TLAB
1695 }
1697 if (JvmtiEnv::environments_might_exist()) {
1698 JvmtiExport::cleanup_thread(this);
1699 }
1701 #ifndef SERIALGC
1702 // We must flush G1-related buffers before removing a thread from
1703 // the list of active threads.
1704 if (UseG1GC) {
1705 flush_barrier_queues();
1706 }
1707 #endif
1709 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1710 Threads::remove(this);
1711 }
1713 #ifndef SERIALGC
1714 // Flush G1-related queues.
1715 void JavaThread::flush_barrier_queues() {
1716 satb_mark_queue().flush();
1717 dirty_card_queue().flush();
1718 }
1720 void JavaThread::initialize_queues() {
1721 assert(!SafepointSynchronize::is_at_safepoint(),
1722 "we should not be at a safepoint");
1724 ObjPtrQueue& satb_queue = satb_mark_queue();
1725 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1726 // The SATB queue should have been constructed with its active
1727 // field set to false.
1728 assert(!satb_queue.is_active(), "SATB queue should not be active");
1729 assert(satb_queue.is_empty(), "SATB queue should be empty");
1730 // If we are creating the thread during a marking cycle, we should
1731 // set the active field of the SATB queue to true.
1732 if (satb_queue_set.is_active()) {
1733 satb_queue.set_active(true);
1734 }
1736 DirtyCardQueue& dirty_queue = dirty_card_queue();
1737 // The dirty card queue should have been constructed with its
1738 // active field set to true.
1739 assert(dirty_queue.is_active(), "dirty card queue should be active");
1740 }
1741 #endif // !SERIALGC
1743 void JavaThread::cleanup_failed_attach_current_thread() {
1744 if (get_thread_profiler() != NULL) {
1745 get_thread_profiler()->disengage();
1746 ResourceMark rm;
1747 get_thread_profiler()->print(get_thread_name());
1748 }
1750 if (active_handles() != NULL) {
1751 JNIHandleBlock* block = active_handles();
1752 set_active_handles(NULL);
1753 JNIHandleBlock::release_block(block);
1754 }
1756 if (free_handle_block() != NULL) {
1757 JNIHandleBlock* block = free_handle_block();
1758 set_free_handle_block(NULL);
1759 JNIHandleBlock::release_block(block);
1760 }
1762 // These have to be removed while this is still a valid thread.
1763 remove_stack_guard_pages();
1765 if (UseTLAB) {
1766 tlab().make_parsable(true); // retire TLAB, if any
1767 }
1769 #ifndef SERIALGC
1770 if (UseG1GC) {
1771 flush_barrier_queues();
1772 }
1773 #endif
1775 Threads::remove(this);
1776 delete this;
1777 }
1782 JavaThread* JavaThread::active() {
1783 Thread* thread = ThreadLocalStorage::thread();
1784 assert(thread != NULL, "just checking");
1785 if (thread->is_Java_thread()) {
1786 return (JavaThread*) thread;
1787 } else {
1788 assert(thread->is_VM_thread(), "this must be a vm thread");
1789 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1790 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1791 assert(ret->is_Java_thread(), "must be a Java thread");
1792 return ret;
1793 }
1794 }
1796 bool JavaThread::is_lock_owned(address adr) const {
1797 if (Thread::is_lock_owned(adr)) return true;
1799 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1800 if (chunk->contains(adr)) return true;
1801 }
1803 return false;
1804 }
1807 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1808 chunk->set_next(monitor_chunks());
1809 set_monitor_chunks(chunk);
1810 }
1812 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1813 guarantee(monitor_chunks() != NULL, "must be non empty");
1814 if (monitor_chunks() == chunk) {
1815 set_monitor_chunks(chunk->next());
1816 } else {
1817 MonitorChunk* prev = monitor_chunks();
1818 while (prev->next() != chunk) prev = prev->next();
1819 prev->set_next(chunk->next());
1820 }
1821 }
1823 // JVM support.
1825 // Note: this function shouldn't block if it's called in
1826 // _thread_in_native_trans state (such as from
1827 // check_special_condition_for_native_trans()).
1828 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1830 if (has_last_Java_frame() && has_async_condition()) {
1831 // If we are at a polling page safepoint (not a poll return)
1832 // then we must defer async exception because live registers
1833 // will be clobbered by the exception path. Poll return is
1834 // ok because the call we a returning from already collides
1835 // with exception handling registers and so there is no issue.
1836 // (The exception handling path kills call result registers but
1837 // this is ok since the exception kills the result anyway).
1839 if (is_at_poll_safepoint()) {
1840 // if the code we are returning to has deoptimized we must defer
1841 // the exception otherwise live registers get clobbered on the
1842 // exception path before deoptimization is able to retrieve them.
1843 //
1844 RegisterMap map(this, false);
1845 frame caller_fr = last_frame().sender(&map);
1846 assert(caller_fr.is_compiled_frame(), "what?");
1847 if (caller_fr.is_deoptimized_frame()) {
1848 if (TraceExceptions) {
1849 ResourceMark rm;
1850 tty->print_cr("deferred async exception at compiled safepoint");
1851 }
1852 return;
1853 }
1854 }
1855 }
1857 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
1858 if (condition == _no_async_condition) {
1859 // Conditions have changed since has_special_runtime_exit_condition()
1860 // was called:
1861 // - if we were here only because of an external suspend request,
1862 // then that was taken care of above (or cancelled) so we are done
1863 // - if we were here because of another async request, then it has
1864 // been cleared between the has_special_runtime_exit_condition()
1865 // and now so again we are done
1866 return;
1867 }
1869 // Check for pending async. exception
1870 if (_pending_async_exception != NULL) {
1871 // Only overwrite an already pending exception, if it is not a threadDeath.
1872 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
1874 // We cannot call Exceptions::_throw(...) here because we cannot block
1875 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1877 if (TraceExceptions) {
1878 ResourceMark rm;
1879 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
1880 if (has_last_Java_frame() ) {
1881 frame f = last_frame();
1882 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
1883 }
1884 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1885 }
1886 _pending_async_exception = NULL;
1887 clear_has_async_exception();
1888 }
1889 }
1891 if (check_unsafe_error &&
1892 condition == _async_unsafe_access_error && !has_pending_exception()) {
1893 condition = _no_async_condition; // done
1894 switch (thread_state()) {
1895 case _thread_in_vm:
1896 {
1897 JavaThread* THREAD = this;
1898 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1899 }
1900 case _thread_in_native:
1901 {
1902 ThreadInVMfromNative tiv(this);
1903 JavaThread* THREAD = this;
1904 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1905 }
1906 case _thread_in_Java:
1907 {
1908 ThreadInVMfromJava tiv(this);
1909 JavaThread* THREAD = this;
1910 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
1911 }
1912 default:
1913 ShouldNotReachHere();
1914 }
1915 }
1917 assert(condition == _no_async_condition || has_pending_exception() ||
1918 (!check_unsafe_error && condition == _async_unsafe_access_error),
1919 "must have handled the async condition, if no exception");
1920 }
1922 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1923 //
1924 // Check for pending external suspend. Internal suspend requests do
1925 // not use handle_special_runtime_exit_condition().
1926 // If JNIEnv proxies are allowed, don't self-suspend if the target
1927 // thread is not the current thread. In older versions of jdbx, jdbx
1928 // threads could call into the VM with another thread's JNIEnv so we
1929 // can be here operating on behalf of a suspended thread (4432884).
1930 bool do_self_suspend = is_external_suspend_with_lock();
1931 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
1932 //
1933 // Because thread is external suspended the safepoint code will count
1934 // thread as at a safepoint. This can be odd because we can be here
1935 // as _thread_in_Java which would normally transition to _thread_blocked
1936 // at a safepoint. We would like to mark the thread as _thread_blocked
1937 // before calling java_suspend_self like all other callers of it but
1938 // we must then observe proper safepoint protocol. (We can't leave
1939 // _thread_blocked with a safepoint in progress). However we can be
1940 // here as _thread_in_native_trans so we can't use a normal transition
1941 // constructor/destructor pair because they assert on that type of
1942 // transition. We could do something like:
1943 //
1944 // JavaThreadState state = thread_state();
1945 // set_thread_state(_thread_in_vm);
1946 // {
1947 // ThreadBlockInVM tbivm(this);
1948 // java_suspend_self()
1949 // }
1950 // set_thread_state(_thread_in_vm_trans);
1951 // if (safepoint) block;
1952 // set_thread_state(state);
1953 //
1954 // but that is pretty messy. Instead we just go with the way the
1955 // code has worked before and note that this is the only path to
1956 // java_suspend_self that doesn't put the thread in _thread_blocked
1957 // mode.
1959 frame_anchor()->make_walkable(this);
1960 java_suspend_self();
1962 // We might be here for reasons in addition to the self-suspend request
1963 // so check for other async requests.
1964 }
1966 if (check_asyncs) {
1967 check_and_handle_async_exceptions();
1968 }
1969 }
1971 void JavaThread::send_thread_stop(oop java_throwable) {
1972 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
1973 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
1974 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
1976 // Do not throw asynchronous exceptions against the compiler thread
1977 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
1978 if (is_Compiler_thread()) return;
1980 {
1981 // Actually throw the Throwable against the target Thread - however
1982 // only if there is no thread death exception installed already.
1983 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
1984 // If the topmost frame is a runtime stub, then we are calling into
1985 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1986 // must deoptimize the caller before continuing, as the compiled exception handler table
1987 // may not be valid
1988 if (has_last_Java_frame()) {
1989 frame f = last_frame();
1990 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
1991 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
1992 RegisterMap reg_map(this, UseBiasedLocking);
1993 frame compiled_frame = f.sender(®_map);
1994 if (compiled_frame.can_be_deoptimized()) {
1995 Deoptimization::deoptimize(this, compiled_frame, ®_map);
1996 }
1997 }
1998 }
2000 // Set async. pending exception in thread.
2001 set_pending_async_exception(java_throwable);
2003 if (TraceExceptions) {
2004 ResourceMark rm;
2005 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
2006 }
2007 // for AbortVMOnException flag
2008 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
2009 }
2010 }
2013 // Interrupt thread so it will wake up from a potential wait()
2014 Thread::interrupt(this);
2015 }
2017 // External suspension mechanism.
2018 //
2019 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2020 // to any VM_locks and it is at a transition
2021 // Self-suspension will happen on the transition out of the vm.
2022 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2023 //
2024 // Guarantees on return:
2025 // + Target thread will not execute any new bytecode (that's why we need to
2026 // force a safepoint)
2027 // + Target thread will not enter any new monitors
2028 //
2029 void JavaThread::java_suspend() {
2030 { MutexLocker mu(Threads_lock);
2031 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2032 return;
2033 }
2034 }
2036 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2037 if (!is_external_suspend()) {
2038 // a racing resume has cancelled us; bail out now
2039 return;
2040 }
2042 // suspend is done
2043 uint32_t debug_bits = 0;
2044 // Warning: is_ext_suspend_completed() may temporarily drop the
2045 // SR_lock to allow the thread to reach a stable thread state if
2046 // it is currently in a transient thread state.
2047 if (is_ext_suspend_completed(false /* !called_by_wait */,
2048 SuspendRetryDelay, &debug_bits) ) {
2049 return;
2050 }
2051 }
2053 VM_ForceSafepoint vm_suspend;
2054 VMThread::execute(&vm_suspend);
2055 }
2057 // Part II of external suspension.
2058 // A JavaThread self suspends when it detects a pending external suspend
2059 // request. This is usually on transitions. It is also done in places
2060 // where continuing to the next transition would surprise the caller,
2061 // e.g., monitor entry.
2062 //
2063 // Returns the number of times that the thread self-suspended.
2064 //
2065 // Note: DO NOT call java_suspend_self() when you just want to block current
2066 // thread. java_suspend_self() is the second stage of cooperative
2067 // suspension for external suspend requests and should only be used
2068 // to complete an external suspend request.
2069 //
2070 int JavaThread::java_suspend_self() {
2071 int ret = 0;
2073 // we are in the process of exiting so don't suspend
2074 if (is_exiting()) {
2075 clear_external_suspend();
2076 return ret;
2077 }
2079 assert(_anchor.walkable() ||
2080 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2081 "must have walkable stack");
2083 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2085 assert(!this->is_ext_suspended(),
2086 "a thread trying to self-suspend should not already be suspended");
2088 if (this->is_suspend_equivalent()) {
2089 // If we are self-suspending as a result of the lifting of a
2090 // suspend equivalent condition, then the suspend_equivalent
2091 // flag is not cleared until we set the ext_suspended flag so
2092 // that wait_for_ext_suspend_completion() returns consistent
2093 // results.
2094 this->clear_suspend_equivalent();
2095 }
2097 // A racing resume may have cancelled us before we grabbed SR_lock
2098 // above. Or another external suspend request could be waiting for us
2099 // by the time we return from SR_lock()->wait(). The thread
2100 // that requested the suspension may already be trying to walk our
2101 // stack and if we return now, we can change the stack out from under
2102 // it. This would be a "bad thing (TM)" and cause the stack walker
2103 // to crash. We stay self-suspended until there are no more pending
2104 // external suspend requests.
2105 while (is_external_suspend()) {
2106 ret++;
2107 this->set_ext_suspended();
2109 // _ext_suspended flag is cleared by java_resume()
2110 while (is_ext_suspended()) {
2111 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2112 }
2113 }
2115 return ret;
2116 }
2118 #ifdef ASSERT
2119 // verify the JavaThread has not yet been published in the Threads::list, and
2120 // hence doesn't need protection from concurrent access at this stage
2121 void JavaThread::verify_not_published() {
2122 if (!Threads_lock->owned_by_self()) {
2123 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2124 assert( !Threads::includes(this),
2125 "java thread shouldn't have been published yet!");
2126 }
2127 else {
2128 assert( !Threads::includes(this),
2129 "java thread shouldn't have been published yet!");
2130 }
2131 }
2132 #endif
2134 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2135 // progress or when _suspend_flags is non-zero.
2136 // Current thread needs to self-suspend if there is a suspend request and/or
2137 // block if a safepoint is in progress.
2138 // Async exception ISN'T checked.
2139 // Note only the ThreadInVMfromNative transition can call this function
2140 // directly and when thread state is _thread_in_native_trans
2141 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2142 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2144 JavaThread *curJT = JavaThread::current();
2145 bool do_self_suspend = thread->is_external_suspend();
2147 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2149 // If JNIEnv proxies are allowed, don't self-suspend if the target
2150 // thread is not the current thread. In older versions of jdbx, jdbx
2151 // threads could call into the VM with another thread's JNIEnv so we
2152 // can be here operating on behalf of a suspended thread (4432884).
2153 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2154 JavaThreadState state = thread->thread_state();
2156 // We mark this thread_blocked state as a suspend-equivalent so
2157 // that a caller to is_ext_suspend_completed() won't be confused.
2158 // The suspend-equivalent state is cleared by java_suspend_self().
2159 thread->set_suspend_equivalent();
2161 // If the safepoint code sees the _thread_in_native_trans state, it will
2162 // wait until the thread changes to other thread state. There is no
2163 // guarantee on how soon we can obtain the SR_lock and complete the
2164 // self-suspend request. It would be a bad idea to let safepoint wait for
2165 // too long. Temporarily change the state to _thread_blocked to
2166 // let the VM thread know that this thread is ready for GC. The problem
2167 // of changing thread state is that safepoint could happen just after
2168 // java_suspend_self() returns after being resumed, and VM thread will
2169 // see the _thread_blocked state. We must check for safepoint
2170 // after restoring the state and make sure we won't leave while a safepoint
2171 // is in progress.
2172 thread->set_thread_state(_thread_blocked);
2173 thread->java_suspend_self();
2174 thread->set_thread_state(state);
2175 // Make sure new state is seen by VM thread
2176 if (os::is_MP()) {
2177 if (UseMembar) {
2178 // Force a fence between the write above and read below
2179 OrderAccess::fence();
2180 } else {
2181 // Must use this rather than serialization page in particular on Windows
2182 InterfaceSupport::serialize_memory(thread);
2183 }
2184 }
2185 }
2187 if (SafepointSynchronize::do_call_back()) {
2188 // If we are safepointing, then block the caller which may not be
2189 // the same as the target thread (see above).
2190 SafepointSynchronize::block(curJT);
2191 }
2193 if (thread->is_deopt_suspend()) {
2194 thread->clear_deopt_suspend();
2195 RegisterMap map(thread, false);
2196 frame f = thread->last_frame();
2197 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2198 f = f.sender(&map);
2199 }
2200 if (f.id() == thread->must_deopt_id()) {
2201 thread->clear_must_deopt_id();
2202 f.deoptimize(thread);
2203 } else {
2204 fatal("missed deoptimization!");
2205 }
2206 }
2207 }
2209 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2210 // progress or when _suspend_flags is non-zero.
2211 // Current thread needs to self-suspend if there is a suspend request and/or
2212 // block if a safepoint is in progress.
2213 // Also check for pending async exception (not including unsafe access error).
2214 // Note only the native==>VM/Java barriers can call this function and when
2215 // thread state is _thread_in_native_trans.
2216 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2217 check_safepoint_and_suspend_for_native_trans(thread);
2219 if (thread->has_async_exception()) {
2220 // We are in _thread_in_native_trans state, don't handle unsafe
2221 // access error since that may block.
2222 thread->check_and_handle_async_exceptions(false);
2223 }
2224 }
2226 // We need to guarantee the Threads_lock here, since resumes are not
2227 // allowed during safepoint synchronization
2228 // Can only resume from an external suspension
2229 void JavaThread::java_resume() {
2230 assert_locked_or_safepoint(Threads_lock);
2232 // Sanity check: thread is gone, has started exiting or the thread
2233 // was not externally suspended.
2234 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2235 return;
2236 }
2238 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2240 clear_external_suspend();
2242 if (is_ext_suspended()) {
2243 clear_ext_suspended();
2244 SR_lock()->notify_all();
2245 }
2246 }
2248 void JavaThread::create_stack_guard_pages() {
2249 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2250 address low_addr = stack_base() - stack_size();
2251 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2253 int allocate = os::allocate_stack_guard_pages();
2254 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2256 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2257 warning("Attempt to allocate stack guard pages failed.");
2258 return;
2259 }
2261 if (os::guard_memory((char *) low_addr, len)) {
2262 _stack_guard_state = stack_guard_enabled;
2263 } else {
2264 warning("Attempt to protect stack guard pages failed.");
2265 if (os::uncommit_memory((char *) low_addr, len)) {
2266 warning("Attempt to deallocate stack guard pages failed.");
2267 }
2268 }
2269 }
2271 void JavaThread::remove_stack_guard_pages() {
2272 if (_stack_guard_state == stack_guard_unused) return;
2273 address low_addr = stack_base() - stack_size();
2274 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2276 if (os::allocate_stack_guard_pages()) {
2277 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2278 _stack_guard_state = stack_guard_unused;
2279 } else {
2280 warning("Attempt to deallocate stack guard pages failed.");
2281 }
2282 } else {
2283 if (_stack_guard_state == stack_guard_unused) return;
2284 if (os::unguard_memory((char *) low_addr, len)) {
2285 _stack_guard_state = stack_guard_unused;
2286 } else {
2287 warning("Attempt to unprotect stack guard pages failed.");
2288 }
2289 }
2290 }
2292 void JavaThread::enable_stack_yellow_zone() {
2293 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2294 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2296 // The base notation is from the stacks point of view, growing downward.
2297 // We need to adjust it to work correctly with guard_memory()
2298 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2300 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2301 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2303 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2304 _stack_guard_state = stack_guard_enabled;
2305 } else {
2306 warning("Attempt to guard stack yellow zone failed.");
2307 }
2308 enable_register_stack_guard();
2309 }
2311 void JavaThread::disable_stack_yellow_zone() {
2312 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2313 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2315 // Simply return if called for a thread that does not use guard pages.
2316 if (_stack_guard_state == stack_guard_unused) return;
2318 // The base notation is from the stacks point of view, growing downward.
2319 // We need to adjust it to work correctly with guard_memory()
2320 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2322 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2323 _stack_guard_state = stack_guard_yellow_disabled;
2324 } else {
2325 warning("Attempt to unguard stack yellow zone failed.");
2326 }
2327 disable_register_stack_guard();
2328 }
2330 void JavaThread::enable_stack_red_zone() {
2331 // The base notation is from the stacks point of view, growing downward.
2332 // We need to adjust it to work correctly with guard_memory()
2333 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2334 address base = stack_red_zone_base() - stack_red_zone_size();
2336 guarantee(base < stack_base(),"Error calculating stack red zone");
2337 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2339 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2340 warning("Attempt to guard stack red zone failed.");
2341 }
2342 }
2344 void JavaThread::disable_stack_red_zone() {
2345 // The base notation is from the stacks point of view, growing downward.
2346 // We need to adjust it to work correctly with guard_memory()
2347 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2348 address base = stack_red_zone_base() - stack_red_zone_size();
2349 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2350 warning("Attempt to unguard stack red zone failed.");
2351 }
2352 }
2354 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2355 // ignore is there is no stack
2356 if (!has_last_Java_frame()) return;
2357 // traverse the stack frames. Starts from top frame.
2358 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2359 frame* fr = fst.current();
2360 f(fr, fst.register_map());
2361 }
2362 }
2365 #ifndef PRODUCT
2366 // Deoptimization
2367 // Function for testing deoptimization
2368 void JavaThread::deoptimize() {
2369 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2370 StackFrameStream fst(this, UseBiasedLocking);
2371 bool deopt = false; // Dump stack only if a deopt actually happens.
2372 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2373 // Iterate over all frames in the thread and deoptimize
2374 for(; !fst.is_done(); fst.next()) {
2375 if(fst.current()->can_be_deoptimized()) {
2377 if (only_at) {
2378 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2379 // consists of comma or carriage return separated numbers so
2380 // search for the current bci in that string.
2381 address pc = fst.current()->pc();
2382 nmethod* nm = (nmethod*) fst.current()->cb();
2383 ScopeDesc* sd = nm->scope_desc_at( pc);
2384 char buffer[8];
2385 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2386 size_t len = strlen(buffer);
2387 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2388 while (found != NULL) {
2389 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2390 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2391 // Check that the bci found is bracketed by terminators.
2392 break;
2393 }
2394 found = strstr(found + 1, buffer);
2395 }
2396 if (!found) {
2397 continue;
2398 }
2399 }
2401 if (DebugDeoptimization && !deopt) {
2402 deopt = true; // One-time only print before deopt
2403 tty->print_cr("[BEFORE Deoptimization]");
2404 trace_frames();
2405 trace_stack();
2406 }
2407 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2408 }
2409 }
2411 if (DebugDeoptimization && deopt) {
2412 tty->print_cr("[AFTER Deoptimization]");
2413 trace_frames();
2414 }
2415 }
2418 // Make zombies
2419 void JavaThread::make_zombies() {
2420 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2421 if (fst.current()->can_be_deoptimized()) {
2422 // it is a Java nmethod
2423 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2424 nm->make_not_entrant();
2425 }
2426 }
2427 }
2428 #endif // PRODUCT
2431 void JavaThread::deoptimized_wrt_marked_nmethods() {
2432 if (!has_last_Java_frame()) return;
2433 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2434 StackFrameStream fst(this, UseBiasedLocking);
2435 for(; !fst.is_done(); fst.next()) {
2436 if (fst.current()->should_be_deoptimized()) {
2437 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2438 }
2439 }
2440 }
2443 // GC support
2444 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2446 void JavaThread::gc_epilogue() {
2447 frames_do(frame_gc_epilogue);
2448 }
2451 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2453 void JavaThread::gc_prologue() {
2454 frames_do(frame_gc_prologue);
2455 }
2457 // If the caller is a NamedThread, then remember, in the current scope,
2458 // the given JavaThread in its _processed_thread field.
2459 class RememberProcessedThread: public StackObj {
2460 NamedThread* _cur_thr;
2461 public:
2462 RememberProcessedThread(JavaThread* jthr) {
2463 Thread* thread = Thread::current();
2464 if (thread->is_Named_thread()) {
2465 _cur_thr = (NamedThread *)thread;
2466 _cur_thr->set_processed_thread(jthr);
2467 } else {
2468 _cur_thr = NULL;
2469 }
2470 }
2472 ~RememberProcessedThread() {
2473 if (_cur_thr) {
2474 _cur_thr->set_processed_thread(NULL);
2475 }
2476 }
2477 };
2479 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2480 // Verify that the deferred card marks have been flushed.
2481 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2483 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2484 // since there may be more than one thread using each ThreadProfiler.
2486 // Traverse the GCHandles
2487 Thread::oops_do(f, cf);
2489 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2490 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2492 if (has_last_Java_frame()) {
2493 // Record JavaThread to GC thread
2494 RememberProcessedThread rpt(this);
2496 // Traverse the privileged stack
2497 if (_privileged_stack_top != NULL) {
2498 _privileged_stack_top->oops_do(f);
2499 }
2501 // traverse the registered growable array
2502 if (_array_for_gc != NULL) {
2503 for (int index = 0; index < _array_for_gc->length(); index++) {
2504 f->do_oop(_array_for_gc->adr_at(index));
2505 }
2506 }
2508 // Traverse the monitor chunks
2509 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2510 chunk->oops_do(f);
2511 }
2513 // Traverse the execution stack
2514 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2515 fst.current()->oops_do(f, cf, fst.register_map());
2516 }
2517 }
2519 // callee_target is never live across a gc point so NULL it here should
2520 // it still contain a methdOop.
2522 set_callee_target(NULL);
2524 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2525 // If we have deferred set_locals there might be oops waiting to be
2526 // written
2527 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2528 if (list != NULL) {
2529 for (int i = 0; i < list->length(); i++) {
2530 list->at(i)->oops_do(f);
2531 }
2532 }
2534 // Traverse instance variables at the end since the GC may be moving things
2535 // around using this function
2536 f->do_oop((oop*) &_threadObj);
2537 f->do_oop((oop*) &_vm_result);
2538 f->do_oop((oop*) &_vm_result_2);
2539 f->do_oop((oop*) &_exception_oop);
2540 f->do_oop((oop*) &_pending_async_exception);
2542 if (jvmti_thread_state() != NULL) {
2543 jvmti_thread_state()->oops_do(f);
2544 }
2545 }
2547 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2548 Thread::nmethods_do(cf); // (super method is a no-op)
2550 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2551 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2553 if (has_last_Java_frame()) {
2554 // Traverse the execution stack
2555 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2556 fst.current()->nmethods_do(cf);
2557 }
2558 }
2559 }
2561 // Printing
2562 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2563 switch (_thread_state) {
2564 case _thread_uninitialized: return "_thread_uninitialized";
2565 case _thread_new: return "_thread_new";
2566 case _thread_new_trans: return "_thread_new_trans";
2567 case _thread_in_native: return "_thread_in_native";
2568 case _thread_in_native_trans: return "_thread_in_native_trans";
2569 case _thread_in_vm: return "_thread_in_vm";
2570 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2571 case _thread_in_Java: return "_thread_in_Java";
2572 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2573 case _thread_blocked: return "_thread_blocked";
2574 case _thread_blocked_trans: return "_thread_blocked_trans";
2575 default: return "unknown thread state";
2576 }
2577 }
2579 #ifndef PRODUCT
2580 void JavaThread::print_thread_state_on(outputStream *st) const {
2581 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2582 };
2583 void JavaThread::print_thread_state() const {
2584 print_thread_state_on(tty);
2585 };
2586 #endif // PRODUCT
2588 // Called by Threads::print() for VM_PrintThreads operation
2589 void JavaThread::print_on(outputStream *st) const {
2590 st->print("\"%s\" ", get_thread_name());
2591 oop thread_oop = threadObj();
2592 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2593 Thread::print_on(st);
2594 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2595 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2596 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2597 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2598 }
2599 #ifndef PRODUCT
2600 print_thread_state_on(st);
2601 _safepoint_state->print_on(st);
2602 #endif // PRODUCT
2603 }
2605 // Called by fatal error handler. The difference between this and
2606 // JavaThread::print() is that we can't grab lock or allocate memory.
2607 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2608 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2609 oop thread_obj = threadObj();
2610 if (thread_obj != NULL) {
2611 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2612 }
2613 st->print(" [");
2614 st->print("%s", _get_thread_state_name(_thread_state));
2615 if (osthread()) {
2616 st->print(", id=%d", osthread()->thread_id());
2617 }
2618 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2619 _stack_base - _stack_size, _stack_base);
2620 st->print("]");
2621 return;
2622 }
2624 // Verification
2626 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2628 void JavaThread::verify() {
2629 // Verify oops in the thread.
2630 oops_do(&VerifyOopClosure::verify_oop, NULL);
2632 // Verify the stack frames.
2633 frames_do(frame_verify);
2634 }
2636 // CR 6300358 (sub-CR 2137150)
2637 // Most callers of this method assume that it can't return NULL but a
2638 // thread may not have a name whilst it is in the process of attaching to
2639 // the VM - see CR 6412693, and there are places where a JavaThread can be
2640 // seen prior to having it's threadObj set (eg JNI attaching threads and
2641 // if vm exit occurs during initialization). These cases can all be accounted
2642 // for such that this method never returns NULL.
2643 const char* JavaThread::get_thread_name() const {
2644 #ifdef ASSERT
2645 // early safepoints can hit while current thread does not yet have TLS
2646 if (!SafepointSynchronize::is_at_safepoint()) {
2647 Thread *cur = Thread::current();
2648 if (!(cur->is_Java_thread() && cur == this)) {
2649 // Current JavaThreads are allowed to get their own name without
2650 // the Threads_lock.
2651 assert_locked_or_safepoint(Threads_lock);
2652 }
2653 }
2654 #endif // ASSERT
2655 return get_thread_name_string();
2656 }
2658 // Returns a non-NULL representation of this thread's name, or a suitable
2659 // descriptive string if there is no set name
2660 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2661 const char* name_str;
2662 oop thread_obj = threadObj();
2663 if (thread_obj != NULL) {
2664 typeArrayOop name = java_lang_Thread::name(thread_obj);
2665 if (name != NULL) {
2666 if (buf == NULL) {
2667 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2668 }
2669 else {
2670 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2671 }
2672 }
2673 else if (is_attaching()) { // workaround for 6412693 - see 6404306
2674 name_str = "<no-name - thread is attaching>";
2675 }
2676 else {
2677 name_str = Thread::name();
2678 }
2679 }
2680 else {
2681 name_str = Thread::name();
2682 }
2683 assert(name_str != NULL, "unexpected NULL thread name");
2684 return name_str;
2685 }
2688 const char* JavaThread::get_threadgroup_name() const {
2689 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2690 oop thread_obj = threadObj();
2691 if (thread_obj != NULL) {
2692 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2693 if (thread_group != NULL) {
2694 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2695 // ThreadGroup.name can be null
2696 if (name != NULL) {
2697 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2698 return str;
2699 }
2700 }
2701 }
2702 return NULL;
2703 }
2705 const char* JavaThread::get_parent_name() const {
2706 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2707 oop thread_obj = threadObj();
2708 if (thread_obj != NULL) {
2709 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2710 if (thread_group != NULL) {
2711 oop parent = java_lang_ThreadGroup::parent(thread_group);
2712 if (parent != NULL) {
2713 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2714 // ThreadGroup.name can be null
2715 if (name != NULL) {
2716 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2717 return str;
2718 }
2719 }
2720 }
2721 }
2722 return NULL;
2723 }
2725 ThreadPriority JavaThread::java_priority() const {
2726 oop thr_oop = threadObj();
2727 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2728 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2729 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2730 return priority;
2731 }
2733 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2735 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2736 // Link Java Thread object <-> C++ Thread
2738 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2739 // and put it into a new Handle. The Handle "thread_oop" can then
2740 // be used to pass the C++ thread object to other methods.
2742 // Set the Java level thread object (jthread) field of the
2743 // new thread (a JavaThread *) to C++ thread object using the
2744 // "thread_oop" handle.
2746 // Set the thread field (a JavaThread *) of the
2747 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2749 Handle thread_oop(Thread::current(),
2750 JNIHandles::resolve_non_null(jni_thread));
2751 assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
2752 "must be initialized");
2753 set_threadObj(thread_oop());
2754 java_lang_Thread::set_thread(thread_oop(), this);
2756 if (prio == NoPriority) {
2757 prio = java_lang_Thread::priority(thread_oop());
2758 assert(prio != NoPriority, "A valid priority should be present");
2759 }
2761 // Push the Java priority down to the native thread; needs Threads_lock
2762 Thread::set_priority(this, prio);
2764 // Add the new thread to the Threads list and set it in motion.
2765 // We must have threads lock in order to call Threads::add.
2766 // It is crucial that we do not block before the thread is
2767 // added to the Threads list for if a GC happens, then the java_thread oop
2768 // will not be visited by GC.
2769 Threads::add(this);
2770 }
2772 oop JavaThread::current_park_blocker() {
2773 // Support for JSR-166 locks
2774 oop thread_oop = threadObj();
2775 if (thread_oop != NULL &&
2776 JDK_Version::current().supports_thread_park_blocker()) {
2777 return java_lang_Thread::park_blocker(thread_oop);
2778 }
2779 return NULL;
2780 }
2783 void JavaThread::print_stack_on(outputStream* st) {
2784 if (!has_last_Java_frame()) return;
2785 ResourceMark rm;
2786 HandleMark hm;
2788 RegisterMap reg_map(this);
2789 vframe* start_vf = last_java_vframe(®_map);
2790 int count = 0;
2791 for (vframe* f = start_vf; f; f = f->sender() ) {
2792 if (f->is_java_frame()) {
2793 javaVFrame* jvf = javaVFrame::cast(f);
2794 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2796 // Print out lock information
2797 if (JavaMonitorsInStackTrace) {
2798 jvf->print_lock_info_on(st, count);
2799 }
2800 } else {
2801 // Ignore non-Java frames
2802 }
2804 // Bail-out case for too deep stacks
2805 count++;
2806 if (MaxJavaStackTraceDepth == count) return;
2807 }
2808 }
2811 // JVMTI PopFrame support
2812 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2813 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2814 if (in_bytes(size_in_bytes) != 0) {
2815 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes));
2816 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2817 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2818 }
2819 }
2821 void* JavaThread::popframe_preserved_args() {
2822 return _popframe_preserved_args;
2823 }
2825 ByteSize JavaThread::popframe_preserved_args_size() {
2826 return in_ByteSize(_popframe_preserved_args_size);
2827 }
2829 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2830 int sz = in_bytes(popframe_preserved_args_size());
2831 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2832 return in_WordSize(sz / wordSize);
2833 }
2835 void JavaThread::popframe_free_preserved_args() {
2836 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2837 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
2838 _popframe_preserved_args = NULL;
2839 _popframe_preserved_args_size = 0;
2840 }
2842 #ifndef PRODUCT
2844 void JavaThread::trace_frames() {
2845 tty->print_cr("[Describe stack]");
2846 int frame_no = 1;
2847 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2848 tty->print(" %d. ", frame_no++);
2849 fst.current()->print_value_on(tty,this);
2850 tty->cr();
2851 }
2852 }
2855 void JavaThread::trace_stack_from(vframe* start_vf) {
2856 ResourceMark rm;
2857 int vframe_no = 1;
2858 for (vframe* f = start_vf; f; f = f->sender() ) {
2859 if (f->is_java_frame()) {
2860 javaVFrame::cast(f)->print_activation(vframe_no++);
2861 } else {
2862 f->print();
2863 }
2864 if (vframe_no > StackPrintLimit) {
2865 tty->print_cr("...<more frames>...");
2866 return;
2867 }
2868 }
2869 }
2872 void JavaThread::trace_stack() {
2873 if (!has_last_Java_frame()) return;
2874 ResourceMark rm;
2875 HandleMark hm;
2876 RegisterMap reg_map(this);
2877 trace_stack_from(last_java_vframe(®_map));
2878 }
2881 #endif // PRODUCT
2884 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2885 assert(reg_map != NULL, "a map must be given");
2886 frame f = last_frame();
2887 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
2888 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2889 }
2890 return NULL;
2891 }
2894 klassOop JavaThread::security_get_caller_class(int depth) {
2895 vframeStream vfst(this);
2896 vfst.security_get_caller_frame(depth);
2897 if (!vfst.at_end()) {
2898 return vfst.method()->method_holder();
2899 }
2900 return NULL;
2901 }
2903 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
2904 assert(thread->is_Compiler_thread(), "must be compiler thread");
2905 CompileBroker::compiler_thread_loop();
2906 }
2908 // Create a CompilerThread
2909 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
2910 : JavaThread(&compiler_thread_entry) {
2911 _env = NULL;
2912 _log = NULL;
2913 _task = NULL;
2914 _queue = queue;
2915 _counters = counters;
2916 _buffer_blob = NULL;
2918 #ifndef PRODUCT
2919 _ideal_graph_printer = NULL;
2920 #endif
2921 }
2924 // ======= Threads ========
2926 // The Threads class links together all active threads, and provides
2927 // operations over all threads. It is protected by its own Mutex
2928 // lock, which is also used in other contexts to protect thread
2929 // operations from having the thread being operated on from exiting
2930 // and going away unexpectedly (e.g., safepoint synchronization)
2932 JavaThread* Threads::_thread_list = NULL;
2933 int Threads::_number_of_threads = 0;
2934 int Threads::_number_of_non_daemon_threads = 0;
2935 int Threads::_return_code = 0;
2936 size_t JavaThread::_stack_size_at_create = 0;
2938 // All JavaThreads
2939 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
2941 void os_stream();
2943 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
2944 void Threads::threads_do(ThreadClosure* tc) {
2945 assert_locked_or_safepoint(Threads_lock);
2946 // ALL_JAVA_THREADS iterates through all JavaThreads
2947 ALL_JAVA_THREADS(p) {
2948 tc->do_thread(p);
2949 }
2950 // Someday we could have a table or list of all non-JavaThreads.
2951 // For now, just manually iterate through them.
2952 tc->do_thread(VMThread::vm_thread());
2953 Universe::heap()->gc_threads_do(tc);
2954 WatcherThread *wt = WatcherThread::watcher_thread();
2955 // Strictly speaking, the following NULL check isn't sufficient to make sure
2956 // the data for WatcherThread is still valid upon being examined. However,
2957 // considering that WatchThread terminates when the VM is on the way to
2958 // exit at safepoint, the chance of the above is extremely small. The right
2959 // way to prevent termination of WatcherThread would be to acquire
2960 // Terminator_lock, but we can't do that without violating the lock rank
2961 // checking in some cases.
2962 if (wt != NULL)
2963 tc->do_thread(wt);
2965 // If CompilerThreads ever become non-JavaThreads, add them here
2966 }
2968 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
2970 extern void JDK_Version_init();
2972 // Check version
2973 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
2975 // Initialize the output stream module
2976 ostream_init();
2978 // Process java launcher properties.
2979 Arguments::process_sun_java_launcher_properties(args);
2981 // Initialize the os module before using TLS
2982 os::init();
2984 // Initialize system properties.
2985 Arguments::init_system_properties();
2987 // So that JDK version can be used as a discrimintor when parsing arguments
2988 JDK_Version_init();
2990 // Update/Initialize System properties after JDK version number is known
2991 Arguments::init_version_specific_system_properties();
2993 // Parse arguments
2994 jint parse_result = Arguments::parse(args);
2995 if (parse_result != JNI_OK) return parse_result;
2997 if (PauseAtStartup) {
2998 os::pause();
2999 }
3001 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3003 // Record VM creation timing statistics
3004 TraceVmCreationTime create_vm_timer;
3005 create_vm_timer.start();
3007 // Timing (must come after argument parsing)
3008 TraceTime timer("Create VM", TraceStartupTime);
3010 // Initialize the os module after parsing the args
3011 jint os_init_2_result = os::init_2();
3012 if (os_init_2_result != JNI_OK) return os_init_2_result;
3014 // Initialize output stream logging
3015 ostream_init_log();
3017 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3018 // Must be before create_vm_init_agents()
3019 if (Arguments::init_libraries_at_startup()) {
3020 convert_vm_init_libraries_to_agents();
3021 }
3023 // Launch -agentlib/-agentpath and converted -Xrun agents
3024 if (Arguments::init_agents_at_startup()) {
3025 create_vm_init_agents();
3026 }
3028 // Initialize Threads state
3029 _thread_list = NULL;
3030 _number_of_threads = 0;
3031 _number_of_non_daemon_threads = 0;
3033 // Initialize TLS
3034 ThreadLocalStorage::init();
3036 // Initialize global data structures and create system classes in heap
3037 vm_init_globals();
3039 // Attach the main thread to this os thread
3040 JavaThread* main_thread = new JavaThread();
3041 main_thread->set_thread_state(_thread_in_vm);
3042 // must do this before set_active_handles and initialize_thread_local_storage
3043 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3044 // change the stack size recorded here to one based on the java thread
3045 // stacksize. This adjusted size is what is used to figure the placement
3046 // of the guard pages.
3047 main_thread->record_stack_base_and_size();
3048 main_thread->initialize_thread_local_storage();
3050 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3052 if (!main_thread->set_as_starting_thread()) {
3053 vm_shutdown_during_initialization(
3054 "Failed necessary internal allocation. Out of swap space");
3055 delete main_thread;
3056 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3057 return JNI_ENOMEM;
3058 }
3060 // Enable guard page *after* os::create_main_thread(), otherwise it would
3061 // crash Linux VM, see notes in os_linux.cpp.
3062 main_thread->create_stack_guard_pages();
3064 // Initialize Java-Level synchronization subsystem
3065 ObjectMonitor::Initialize() ;
3067 // Initialize global modules
3068 jint status = init_globals();
3069 if (status != JNI_OK) {
3070 delete main_thread;
3071 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3072 return status;
3073 }
3075 // Should be done after the heap is fully created
3076 main_thread->cache_global_variables();
3078 HandleMark hm;
3080 { MutexLocker mu(Threads_lock);
3081 Threads::add(main_thread);
3082 }
3084 // Any JVMTI raw monitors entered in onload will transition into
3085 // real raw monitor. VM is setup enough here for raw monitor enter.
3086 JvmtiExport::transition_pending_onload_raw_monitors();
3088 if (VerifyBeforeGC &&
3089 Universe::heap()->total_collections() >= VerifyGCStartAt) {
3090 Universe::heap()->prepare_for_verify();
3091 Universe::verify(); // make sure we're starting with a clean slate
3092 }
3094 // Create the VMThread
3095 { TraceTime timer("Start VMThread", TraceStartupTime);
3096 VMThread::create();
3097 Thread* vmthread = VMThread::vm_thread();
3099 if (!os::create_thread(vmthread, os::vm_thread))
3100 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3102 // Wait for the VM thread to become ready, and VMThread::run to initialize
3103 // Monitors can have spurious returns, must always check another state flag
3104 {
3105 MutexLocker ml(Notify_lock);
3106 os::start_thread(vmthread);
3107 while (vmthread->active_handles() == NULL) {
3108 Notify_lock->wait();
3109 }
3110 }
3111 }
3113 assert (Universe::is_fully_initialized(), "not initialized");
3114 EXCEPTION_MARK;
3116 // At this point, the Universe is initialized, but we have not executed
3117 // any byte code. Now is a good time (the only time) to dump out the
3118 // internal state of the JVM for sharing.
3120 if (DumpSharedSpaces) {
3121 Universe::heap()->preload_and_dump(CHECK_0);
3122 ShouldNotReachHere();
3123 }
3125 // Always call even when there are not JVMTI environments yet, since environments
3126 // may be attached late and JVMTI must track phases of VM execution
3127 JvmtiExport::enter_start_phase();
3129 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3130 JvmtiExport::post_vm_start();
3132 {
3133 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3135 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3136 create_vm_init_libraries();
3137 }
3139 if (InitializeJavaLangString) {
3140 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3141 } else {
3142 warning("java.lang.String not initialized");
3143 }
3145 if (AggressiveOpts) {
3146 {
3147 // Forcibly initialize java/util/HashMap and mutate the private
3148 // static final "frontCacheEnabled" field before we start creating instances
3149 #ifdef ASSERT
3150 klassOop tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3151 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
3152 #endif
3153 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3154 KlassHandle k = KlassHandle(THREAD, k_o);
3155 guarantee(k.not_null(), "Must find java/util/HashMap");
3156 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3157 ik->initialize(CHECK_0);
3158 fieldDescriptor fd;
3159 // Possible we might not find this field; if so, don't break
3160 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3161 k()->bool_field_put(fd.offset(), true);
3162 }
3163 }
3165 if (UseStringCache) {
3166 // Forcibly initialize java/lang/StringValue and mutate the private
3167 // static final "stringCacheEnabled" field before we start creating instances
3168 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3169 // Possible that StringValue isn't present: if so, silently don't break
3170 if (k_o != NULL) {
3171 KlassHandle k = KlassHandle(THREAD, k_o);
3172 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3173 ik->initialize(CHECK_0);
3174 fieldDescriptor fd;
3175 // Possible we might not find this field: if so, silently don't break
3176 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3177 k()->bool_field_put(fd.offset(), true);
3178 }
3179 }
3180 }
3181 }
3183 // Initialize java_lang.System (needed before creating the thread)
3184 if (InitializeJavaLangSystem) {
3185 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3186 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3187 Handle thread_group = create_initial_thread_group(CHECK_0);
3188 Universe::set_main_thread_group(thread_group());
3189 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3190 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3191 main_thread->set_threadObj(thread_object);
3192 // Set thread status to running since main thread has
3193 // been started and running.
3194 java_lang_Thread::set_thread_status(thread_object,
3195 java_lang_Thread::RUNNABLE);
3197 // The VM preresolve methods to these classes. Make sure that get initialized
3198 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3199 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3200 // The VM creates & returns objects of this class. Make sure it's initialized.
3201 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3202 call_initializeSystemClass(CHECK_0);
3203 } else {
3204 warning("java.lang.System not initialized");
3205 }
3207 // an instance of OutOfMemory exception has been allocated earlier
3208 if (InitializeJavaLangExceptionsErrors) {
3209 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3210 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3211 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3212 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3213 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3214 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3215 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3216 } else {
3217 warning("java.lang.OutOfMemoryError has not been initialized");
3218 warning("java.lang.NullPointerException has not been initialized");
3219 warning("java.lang.ClassCastException has not been initialized");
3220 warning("java.lang.ArrayStoreException has not been initialized");
3221 warning("java.lang.ArithmeticException has not been initialized");
3222 warning("java.lang.StackOverflowError has not been initialized");
3223 }
3224 }
3226 // See : bugid 4211085.
3227 // Background : the static initializer of java.lang.Compiler tries to read
3228 // property"java.compiler" and read & write property "java.vm.info".
3229 // When a security manager is installed through the command line
3230 // option "-Djava.security.manager", the above properties are not
3231 // readable and the static initializer for java.lang.Compiler fails
3232 // resulting in a NoClassDefFoundError. This can happen in any
3233 // user code which calls methods in java.lang.Compiler.
3234 // Hack : the hack is to pre-load and initialize this class, so that only
3235 // system domains are on the stack when the properties are read.
3236 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3237 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3238 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3239 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3240 // Once that is done, we should remove this hack.
3241 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3243 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3244 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3245 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3246 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3247 // This should also be taken out as soon as 4211383 gets fixed.
3248 reset_vm_info_property(CHECK_0);
3250 quicken_jni_functions();
3252 // Set flag that basic initialization has completed. Used by exceptions and various
3253 // debug stuff, that does not work until all basic classes have been initialized.
3254 set_init_completed();
3256 HS_DTRACE_PROBE(hotspot, vm__init__end);
3258 // record VM initialization completion time
3259 Management::record_vm_init_completed();
3261 // Compute system loader. Note that this has to occur after set_init_completed, since
3262 // valid exceptions may be thrown in the process.
3263 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3264 // set_init_completed has just been called, causing exceptions not to be shortcut
3265 // anymore. We call vm_exit_during_initialization directly instead.
3266 SystemDictionary::compute_java_system_loader(THREAD);
3267 if (HAS_PENDING_EXCEPTION) {
3268 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3269 }
3271 #ifndef SERIALGC
3272 // Support for ConcurrentMarkSweep. This should be cleaned up
3273 // and better encapsulated. The ugly nested if test would go away
3274 // once things are properly refactored. XXX YSR
3275 if (UseConcMarkSweepGC || UseG1GC) {
3276 if (UseConcMarkSweepGC) {
3277 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3278 } else {
3279 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3280 }
3281 if (HAS_PENDING_EXCEPTION) {
3282 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3283 }
3284 }
3285 #endif // SERIALGC
3287 // Always call even when there are not JVMTI environments yet, since environments
3288 // may be attached late and JVMTI must track phases of VM execution
3289 JvmtiExport::enter_live_phase();
3291 // Signal Dispatcher needs to be started before VMInit event is posted
3292 os::signal_init();
3294 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3295 if (!DisableAttachMechanism) {
3296 if (StartAttachListener || AttachListener::init_at_startup()) {
3297 AttachListener::init();
3298 }
3299 }
3301 // Launch -Xrun agents
3302 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3303 // back-end can launch with -Xdebug -Xrunjdwp.
3304 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3305 create_vm_init_libraries();
3306 }
3308 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3309 JvmtiExport::post_vm_initialized();
3311 Chunk::start_chunk_pool_cleaner_task();
3313 // initialize compiler(s)
3314 CompileBroker::compilation_init();
3316 Management::initialize(THREAD);
3317 if (HAS_PENDING_EXCEPTION) {
3318 // management agent fails to start possibly due to
3319 // configuration problem and is responsible for printing
3320 // stack trace if appropriate. Simply exit VM.
3321 vm_exit(1);
3322 }
3324 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3325 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3326 if (MemProfiling) MemProfiler::engage();
3327 StatSampler::engage();
3328 if (CheckJNICalls) JniPeriodicChecker::engage();
3330 BiasedLocking::init();
3332 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3333 call_postVMInitHook(THREAD);
3334 // The Java side of PostVMInitHook.run must deal with all
3335 // exceptions and provide means of diagnosis.
3336 if (HAS_PENDING_EXCEPTION) {
3337 CLEAR_PENDING_EXCEPTION;
3338 }
3339 }
3341 // Start up the WatcherThread if there are any periodic tasks
3342 // NOTE: All PeriodicTasks should be registered by now. If they
3343 // aren't, late joiners might appear to start slowly (we might
3344 // take a while to process their first tick).
3345 if (PeriodicTask::num_tasks() > 0) {
3346 WatcherThread::start();
3347 }
3349 // Give os specific code one last chance to start
3350 os::init_3();
3352 create_vm_timer.end();
3353 return JNI_OK;
3354 }
3356 // type for the Agent_OnLoad and JVM_OnLoad entry points
3357 extern "C" {
3358 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3359 }
3360 // Find a command line agent library and return its entry point for
3361 // -agentlib: -agentpath: -Xrun
3362 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3363 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3364 OnLoadEntry_t on_load_entry = NULL;
3365 void *library = agent->os_lib(); // check if we have looked it up before
3367 if (library == NULL) {
3368 char buffer[JVM_MAXPATHLEN];
3369 char ebuf[1024];
3370 const char *name = agent->name();
3371 const char *msg = "Could not find agent library ";
3373 if (agent->is_absolute_path()) {
3374 library = os::dll_load(name, ebuf, sizeof ebuf);
3375 if (library == NULL) {
3376 const char *sub_msg = " in absolute path, with error: ";
3377 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3378 char *buf = NEW_C_HEAP_ARRAY(char, len);
3379 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3380 // If we can't find the agent, exit.
3381 vm_exit_during_initialization(buf, NULL);
3382 FREE_C_HEAP_ARRAY(char, buf);
3383 }
3384 } else {
3385 // Try to load the agent from the standard dll directory
3386 os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
3387 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3388 #ifdef KERNEL
3389 // Download instrument dll
3390 if (library == NULL && strcmp(name, "instrument") == 0) {
3391 char *props = Arguments::get_kernel_properties();
3392 char *home = Arguments::get_java_home();
3393 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false"
3394 " sun.jkernel.DownloadManager -download client_jvm";
3395 size_t length = strlen(props) + strlen(home) + strlen(fmt) + 1;
3396 char *cmd = NEW_C_HEAP_ARRAY(char, length);
3397 jio_snprintf(cmd, length, fmt, home, props);
3398 int status = os::fork_and_exec(cmd);
3399 FreeHeap(props);
3400 if (status == -1) {
3401 warning(cmd);
3402 vm_exit_during_initialization("fork_and_exec failed: %s",
3403 strerror(errno));
3404 }
3405 FREE_C_HEAP_ARRAY(char, cmd);
3406 // when this comes back the instrument.dll should be where it belongs.
3407 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3408 }
3409 #endif // KERNEL
3410 if (library == NULL) { // Try the local directory
3411 char ns[1] = {0};
3412 os::dll_build_name(buffer, sizeof(buffer), ns, name);
3413 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3414 if (library == NULL) {
3415 const char *sub_msg = " on the library path, with error: ";
3416 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3417 char *buf = NEW_C_HEAP_ARRAY(char, len);
3418 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3419 // If we can't find the agent, exit.
3420 vm_exit_during_initialization(buf, NULL);
3421 FREE_C_HEAP_ARRAY(char, buf);
3422 }
3423 }
3424 }
3425 agent->set_os_lib(library);
3426 }
3428 // Find the OnLoad function.
3429 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3430 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index]));
3431 if (on_load_entry != NULL) break;
3432 }
3433 return on_load_entry;
3434 }
3436 // Find the JVM_OnLoad entry point
3437 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3438 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3439 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3440 }
3442 // Find the Agent_OnLoad entry point
3443 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3444 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3445 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3446 }
3448 // For backwards compatibility with -Xrun
3449 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3450 // treated like -agentpath:
3451 // Must be called before agent libraries are created
3452 void Threads::convert_vm_init_libraries_to_agents() {
3453 AgentLibrary* agent;
3454 AgentLibrary* next;
3456 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3457 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3458 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3460 // If there is an JVM_OnLoad function it will get called later,
3461 // otherwise see if there is an Agent_OnLoad
3462 if (on_load_entry == NULL) {
3463 on_load_entry = lookup_agent_on_load(agent);
3464 if (on_load_entry != NULL) {
3465 // switch it to the agent list -- so that Agent_OnLoad will be called,
3466 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3467 Arguments::convert_library_to_agent(agent);
3468 } else {
3469 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3470 }
3471 }
3472 }
3473 }
3475 // Create agents for -agentlib: -agentpath: and converted -Xrun
3476 // Invokes Agent_OnLoad
3477 // Called very early -- before JavaThreads exist
3478 void Threads::create_vm_init_agents() {
3479 extern struct JavaVM_ main_vm;
3480 AgentLibrary* agent;
3482 JvmtiExport::enter_onload_phase();
3483 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3484 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3486 if (on_load_entry != NULL) {
3487 // Invoke the Agent_OnLoad function
3488 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3489 if (err != JNI_OK) {
3490 vm_exit_during_initialization("agent library failed to init", agent->name());
3491 }
3492 } else {
3493 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3494 }
3495 }
3496 JvmtiExport::enter_primordial_phase();
3497 }
3499 extern "C" {
3500 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3501 }
3503 void Threads::shutdown_vm_agents() {
3504 // Send any Agent_OnUnload notifications
3505 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3506 extern struct JavaVM_ main_vm;
3507 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3509 // Find the Agent_OnUnload function.
3510 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3511 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3512 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3514 // Invoke the Agent_OnUnload function
3515 if (unload_entry != NULL) {
3516 JavaThread* thread = JavaThread::current();
3517 ThreadToNativeFromVM ttn(thread);
3518 HandleMark hm(thread);
3519 (*unload_entry)(&main_vm);
3520 break;
3521 }
3522 }
3523 }
3524 }
3526 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3527 // Invokes JVM_OnLoad
3528 void Threads::create_vm_init_libraries() {
3529 extern struct JavaVM_ main_vm;
3530 AgentLibrary* agent;
3532 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3533 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3535 if (on_load_entry != NULL) {
3536 // Invoke the JVM_OnLoad function
3537 JavaThread* thread = JavaThread::current();
3538 ThreadToNativeFromVM ttn(thread);
3539 HandleMark hm(thread);
3540 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3541 if (err != JNI_OK) {
3542 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3543 }
3544 } else {
3545 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3546 }
3547 }
3548 }
3550 // Last thread running calls java.lang.Shutdown.shutdown()
3551 void JavaThread::invoke_shutdown_hooks() {
3552 HandleMark hm(this);
3554 // We could get here with a pending exception, if so clear it now.
3555 if (this->has_pending_exception()) {
3556 this->clear_pending_exception();
3557 }
3559 EXCEPTION_MARK;
3560 klassOop k =
3561 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3562 THREAD);
3563 if (k != NULL) {
3564 // SystemDictionary::resolve_or_null will return null if there was
3565 // an exception. If we cannot load the Shutdown class, just don't
3566 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3567 // and finalizers (if runFinalizersOnExit is set) won't be run.
3568 // Note that if a shutdown hook was registered or runFinalizersOnExit
3569 // was called, the Shutdown class would have already been loaded
3570 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3571 instanceKlassHandle shutdown_klass (THREAD, k);
3572 JavaValue result(T_VOID);
3573 JavaCalls::call_static(&result,
3574 shutdown_klass,
3575 vmSymbols::shutdown_method_name(),
3576 vmSymbols::void_method_signature(),
3577 THREAD);
3578 }
3579 CLEAR_PENDING_EXCEPTION;
3580 }
3582 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3583 // the program falls off the end of main(). Another VM exit path is through
3584 // vm_exit() when the program calls System.exit() to return a value or when
3585 // there is a serious error in VM. The two shutdown paths are not exactly
3586 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3587 // and VM_Exit op at VM level.
3588 //
3589 // Shutdown sequence:
3590 // + Wait until we are the last non-daemon thread to execute
3591 // <-- every thing is still working at this moment -->
3592 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3593 // shutdown hooks, run finalizers if finalization-on-exit
3594 // + Call before_exit(), prepare for VM exit
3595 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3596 // currently the only user of this mechanism is File.deleteOnExit())
3597 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3598 // post thread end and vm death events to JVMTI,
3599 // stop signal thread
3600 // + Call JavaThread::exit(), it will:
3601 // > release JNI handle blocks, remove stack guard pages
3602 // > remove this thread from Threads list
3603 // <-- no more Java code from this thread after this point -->
3604 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3605 // the compiler threads at safepoint
3606 // <-- do not use anything that could get blocked by Safepoint -->
3607 // + Disable tracing at JNI/JVM barriers
3608 // + Set _vm_exited flag for threads that are still running native code
3609 // + Delete this thread
3610 // + Call exit_globals()
3611 // > deletes tty
3612 // > deletes PerfMemory resources
3613 // + Return to caller
3615 bool Threads::destroy_vm() {
3616 JavaThread* thread = JavaThread::current();
3618 // Wait until we are the last non-daemon thread to execute
3619 { MutexLocker nu(Threads_lock);
3620 while (Threads::number_of_non_daemon_threads() > 1 )
3621 // This wait should make safepoint checks, wait without a timeout,
3622 // and wait as a suspend-equivalent condition.
3623 //
3624 // Note: If the FlatProfiler is running and this thread is waiting
3625 // for another non-daemon thread to finish, then the FlatProfiler
3626 // is waiting for the external suspend request on this thread to
3627 // complete. wait_for_ext_suspend_completion() will eventually
3628 // timeout, but that takes time. Making this wait a suspend-
3629 // equivalent condition solves that timeout problem.
3630 //
3631 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3632 Mutex::_as_suspend_equivalent_flag);
3633 }
3635 // Hang forever on exit if we are reporting an error.
3636 if (ShowMessageBoxOnError && is_error_reported()) {
3637 os::infinite_sleep();
3638 }
3640 if (JDK_Version::is_jdk12x_version()) {
3641 // We are the last thread running, so check if finalizers should be run.
3642 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3643 HandleMark rm(thread);
3644 Universe::run_finalizers_on_exit();
3645 } else {
3646 // run Java level shutdown hooks
3647 thread->invoke_shutdown_hooks();
3648 }
3650 before_exit(thread);
3652 thread->exit(true);
3654 // Stop VM thread.
3655 {
3656 // 4945125 The vm thread comes to a safepoint during exit.
3657 // GC vm_operations can get caught at the safepoint, and the
3658 // heap is unparseable if they are caught. Grab the Heap_lock
3659 // to prevent this. The GC vm_operations will not be able to
3660 // queue until after the vm thread is dead.
3661 MutexLocker ml(Heap_lock);
3663 VMThread::wait_for_vm_thread_exit();
3664 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3665 VMThread::destroy();
3666 }
3668 // clean up ideal graph printers
3669 #if defined(COMPILER2) && !defined(PRODUCT)
3670 IdealGraphPrinter::clean_up();
3671 #endif
3673 // Now, all Java threads are gone except daemon threads. Daemon threads
3674 // running Java code or in VM are stopped by the Safepoint. However,
3675 // daemon threads executing native code are still running. But they
3676 // will be stopped at native=>Java/VM barriers. Note that we can't
3677 // simply kill or suspend them, as it is inherently deadlock-prone.
3679 #ifndef PRODUCT
3680 // disable function tracing at JNI/JVM barriers
3681 TraceJNICalls = false;
3682 TraceJVMCalls = false;
3683 TraceRuntimeCalls = false;
3684 #endif
3686 VM_Exit::set_vm_exited();
3688 notify_vm_shutdown();
3690 delete thread;
3692 // exit_globals() will delete tty
3693 exit_globals();
3695 return true;
3696 }
3699 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3700 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3701 return is_supported_jni_version(version);
3702 }
3705 jboolean Threads::is_supported_jni_version(jint version) {
3706 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3707 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3708 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3709 return JNI_FALSE;
3710 }
3713 void Threads::add(JavaThread* p, bool force_daemon) {
3714 // The threads lock must be owned at this point
3715 assert_locked_or_safepoint(Threads_lock);
3717 // See the comment for this method in thread.hpp for its purpose and
3718 // why it is called here.
3719 p->initialize_queues();
3720 p->set_next(_thread_list);
3721 _thread_list = p;
3722 _number_of_threads++;
3723 oop threadObj = p->threadObj();
3724 bool daemon = true;
3725 // Bootstrapping problem: threadObj can be null for initial
3726 // JavaThread (or for threads attached via JNI)
3727 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3728 _number_of_non_daemon_threads++;
3729 daemon = false;
3730 }
3732 ThreadService::add_thread(p, daemon);
3734 // Possible GC point.
3735 Events::log("Thread added: " INTPTR_FORMAT, p);
3736 }
3738 void Threads::remove(JavaThread* p) {
3739 // Extra scope needed for Thread_lock, so we can check
3740 // that we do not remove thread without safepoint code notice
3741 { MutexLocker ml(Threads_lock);
3743 assert(includes(p), "p must be present");
3745 JavaThread* current = _thread_list;
3746 JavaThread* prev = NULL;
3748 while (current != p) {
3749 prev = current;
3750 current = current->next();
3751 }
3753 if (prev) {
3754 prev->set_next(current->next());
3755 } else {
3756 _thread_list = p->next();
3757 }
3758 _number_of_threads--;
3759 oop threadObj = p->threadObj();
3760 bool daemon = true;
3761 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
3762 _number_of_non_daemon_threads--;
3763 daemon = false;
3765 // Only one thread left, do a notify on the Threads_lock so a thread waiting
3766 // on destroy_vm will wake up.
3767 if (number_of_non_daemon_threads() == 1)
3768 Threads_lock->notify_all();
3769 }
3770 ThreadService::remove_thread(p, daemon);
3772 // Make sure that safepoint code disregard this thread. This is needed since
3773 // the thread might mess around with locks after this point. This can cause it
3774 // to do callbacks into the safepoint code. However, the safepoint code is not aware
3775 // of this thread since it is removed from the queue.
3776 p->set_terminated_value();
3777 } // unlock Threads_lock
3779 // Since Events::log uses a lock, we grab it outside the Threads_lock
3780 Events::log("Thread exited: " INTPTR_FORMAT, p);
3781 }
3783 // Threads_lock must be held when this is called (or must be called during a safepoint)
3784 bool Threads::includes(JavaThread* p) {
3785 assert(Threads_lock->is_locked(), "sanity check");
3786 ALL_JAVA_THREADS(q) {
3787 if (q == p ) {
3788 return true;
3789 }
3790 }
3791 return false;
3792 }
3794 // Operations on the Threads list for GC. These are not explicitly locked,
3795 // but the garbage collector must provide a safe context for them to run.
3796 // In particular, these things should never be called when the Threads_lock
3797 // is held by some other thread. (Note: the Safepoint abstraction also
3798 // uses the Threads_lock to gurantee this property. It also makes sure that
3799 // all threads gets blocked when exiting or starting).
3801 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3802 ALL_JAVA_THREADS(p) {
3803 p->oops_do(f, cf);
3804 }
3805 VMThread::vm_thread()->oops_do(f, cf);
3806 }
3808 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) {
3809 // Introduce a mechanism allowing parallel threads to claim threads as
3810 // root groups. Overhead should be small enough to use all the time,
3811 // even in sequential code.
3812 SharedHeap* sh = SharedHeap::heap();
3813 bool is_par = (sh->n_par_threads() > 0);
3814 int cp = SharedHeap::heap()->strong_roots_parity();
3815 ALL_JAVA_THREADS(p) {
3816 if (p->claim_oops_do(is_par, cp)) {
3817 p->oops_do(f, cf);
3818 }
3819 }
3820 VMThread* vmt = VMThread::vm_thread();
3821 if (vmt->claim_oops_do(is_par, cp))
3822 vmt->oops_do(f, cf);
3823 }
3825 #ifndef SERIALGC
3826 // Used by ParallelScavenge
3827 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
3828 ALL_JAVA_THREADS(p) {
3829 q->enqueue(new ThreadRootsTask(p));
3830 }
3831 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
3832 }
3834 // Used by Parallel Old
3835 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
3836 ALL_JAVA_THREADS(p) {
3837 q->enqueue(new ThreadRootsMarkingTask(p));
3838 }
3839 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
3840 }
3841 #endif // SERIALGC
3843 void Threads::nmethods_do(CodeBlobClosure* cf) {
3844 ALL_JAVA_THREADS(p) {
3845 p->nmethods_do(cf);
3846 }
3847 VMThread::vm_thread()->nmethods_do(cf);
3848 }
3850 void Threads::gc_epilogue() {
3851 ALL_JAVA_THREADS(p) {
3852 p->gc_epilogue();
3853 }
3854 }
3856 void Threads::gc_prologue() {
3857 ALL_JAVA_THREADS(p) {
3858 p->gc_prologue();
3859 }
3860 }
3862 void Threads::deoptimized_wrt_marked_nmethods() {
3863 ALL_JAVA_THREADS(p) {
3864 p->deoptimized_wrt_marked_nmethods();
3865 }
3866 }
3869 // Get count Java threads that are waiting to enter the specified monitor.
3870 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
3871 address monitor, bool doLock) {
3872 assert(doLock || SafepointSynchronize::is_at_safepoint(),
3873 "must grab Threads_lock or be at safepoint");
3874 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3876 int i = 0;
3877 {
3878 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3879 ALL_JAVA_THREADS(p) {
3880 if (p->is_Compiler_thread()) continue;
3882 address pending = (address)p->current_pending_monitor();
3883 if (pending == monitor) { // found a match
3884 if (i < count) result->append(p); // save the first count matches
3885 i++;
3886 }
3887 }
3888 }
3889 return result;
3890 }
3893 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
3894 assert(doLock ||
3895 Threads_lock->owned_by_self() ||
3896 SafepointSynchronize::is_at_safepoint(),
3897 "must grab Threads_lock or be at safepoint");
3899 // NULL owner means not locked so we can skip the search
3900 if (owner == NULL) return NULL;
3902 {
3903 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3904 ALL_JAVA_THREADS(p) {
3905 // first, see if owner is the address of a Java thread
3906 if (owner == (address)p) return p;
3907 }
3908 }
3909 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
3910 if (UseHeavyMonitors) return NULL;
3912 //
3913 // If we didn't find a matching Java thread and we didn't force use of
3914 // heavyweight monitors, then the owner is the stack address of the
3915 // Lock Word in the owning Java thread's stack.
3916 //
3917 JavaThread* the_owner = NULL;
3918 {
3919 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3920 ALL_JAVA_THREADS(q) {
3921 if (q->is_lock_owned(owner)) {
3922 the_owner = q;
3923 break;
3924 }
3925 }
3926 }
3927 assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
3928 return the_owner;
3929 }
3931 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3932 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
3933 char buf[32];
3934 st->print_cr(os::local_time_string(buf, sizeof(buf)));
3936 st->print_cr("Full thread dump %s (%s %s):",
3937 Abstract_VM_Version::vm_name(),
3938 Abstract_VM_Version::vm_release(),
3939 Abstract_VM_Version::vm_info_string()
3940 );
3941 st->cr();
3943 #ifndef SERIALGC
3944 // Dump concurrent locks
3945 ConcurrentLocksDump concurrent_locks;
3946 if (print_concurrent_locks) {
3947 concurrent_locks.dump_at_safepoint();
3948 }
3949 #endif // SERIALGC
3951 ALL_JAVA_THREADS(p) {
3952 ResourceMark rm;
3953 p->print_on(st);
3954 if (print_stacks) {
3955 if (internal_format) {
3956 p->trace_stack();
3957 } else {
3958 p->print_stack_on(st);
3959 }
3960 }
3961 st->cr();
3962 #ifndef SERIALGC
3963 if (print_concurrent_locks) {
3964 concurrent_locks.print_locks_on(p, st);
3965 }
3966 #endif // SERIALGC
3967 }
3969 VMThread::vm_thread()->print_on(st);
3970 st->cr();
3971 Universe::heap()->print_gc_threads_on(st);
3972 WatcherThread* wt = WatcherThread::watcher_thread();
3973 if (wt != NULL) wt->print_on(st);
3974 st->cr();
3975 CompileBroker::print_compiler_threads_on(st);
3976 st->flush();
3977 }
3979 // Threads::print_on_error() is called by fatal error handler. It's possible
3980 // that VM is not at safepoint and/or current thread is inside signal handler.
3981 // Don't print stack trace, as the stack may not be walkable. Don't allocate
3982 // memory (even in resource area), it might deadlock the error handler.
3983 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
3984 bool found_current = false;
3985 st->print_cr("Java Threads: ( => current thread )");
3986 ALL_JAVA_THREADS(thread) {
3987 bool is_current = (current == thread);
3988 found_current = found_current || is_current;
3990 st->print("%s", is_current ? "=>" : " ");
3992 st->print(PTR_FORMAT, thread);
3993 st->print(" ");
3994 thread->print_on_error(st, buf, buflen);
3995 st->cr();
3996 }
3997 st->cr();
3999 st->print_cr("Other Threads:");
4000 if (VMThread::vm_thread()) {
4001 bool is_current = (current == VMThread::vm_thread());
4002 found_current = found_current || is_current;
4003 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4005 st->print(PTR_FORMAT, VMThread::vm_thread());
4006 st->print(" ");
4007 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4008 st->cr();
4009 }
4010 WatcherThread* wt = WatcherThread::watcher_thread();
4011 if (wt != NULL) {
4012 bool is_current = (current == wt);
4013 found_current = found_current || is_current;
4014 st->print("%s", is_current ? "=>" : " ");
4016 st->print(PTR_FORMAT, wt);
4017 st->print(" ");
4018 wt->print_on_error(st, buf, buflen);
4019 st->cr();
4020 }
4021 if (!found_current) {
4022 st->cr();
4023 st->print("=>" PTR_FORMAT " (exited) ", current);
4024 current->print_on_error(st, buf, buflen);
4025 st->cr();
4026 }
4027 }
4029 // Internal SpinLock and Mutex
4030 // Based on ParkEvent
4032 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4033 //
4034 // We employ SpinLocks _only for low-contention, fixed-length
4035 // short-duration critical sections where we're concerned
4036 // about native mutex_t or HotSpot Mutex:: latency.
4037 // The mux construct provides a spin-then-block mutual exclusion
4038 // mechanism.
4039 //
4040 // Testing has shown that contention on the ListLock guarding gFreeList
4041 // is common. If we implement ListLock as a simple SpinLock it's common
4042 // for the JVM to devolve to yielding with little progress. This is true
4043 // despite the fact that the critical sections protected by ListLock are
4044 // extremely short.
4045 //
4046 // TODO-FIXME: ListLock should be of type SpinLock.
4047 // We should make this a 1st-class type, integrated into the lock
4048 // hierarchy as leaf-locks. Critically, the SpinLock structure
4049 // should have sufficient padding to avoid false-sharing and excessive
4050 // cache-coherency traffic.
4053 typedef volatile int SpinLockT ;
4055 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4056 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4057 return ; // normal fast-path return
4058 }
4060 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4061 TEVENT (SpinAcquire - ctx) ;
4062 int ctr = 0 ;
4063 int Yields = 0 ;
4064 for (;;) {
4065 while (*adr != 0) {
4066 ++ctr ;
4067 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4068 if (Yields > 5) {
4069 // Consider using a simple NakedSleep() instead.
4070 // Then SpinAcquire could be called by non-JVM threads
4071 Thread::current()->_ParkEvent->park(1) ;
4072 } else {
4073 os::NakedYield() ;
4074 ++Yields ;
4075 }
4076 } else {
4077 SpinPause() ;
4078 }
4079 }
4080 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4081 }
4082 }
4084 void Thread::SpinRelease (volatile int * adr) {
4085 assert (*adr != 0, "invariant") ;
4086 OrderAccess::fence() ; // guarantee at least release consistency.
4087 // Roach-motel semantics.
4088 // It's safe if subsequent LDs and STs float "up" into the critical section,
4089 // but prior LDs and STs within the critical section can't be allowed
4090 // to reorder or float past the ST that releases the lock.
4091 *adr = 0 ;
4092 }
4094 // muxAcquire and muxRelease:
4095 //
4096 // * muxAcquire and muxRelease support a single-word lock-word construct.
4097 // The LSB of the word is set IFF the lock is held.
4098 // The remainder of the word points to the head of a singly-linked list
4099 // of threads blocked on the lock.
4100 //
4101 // * The current implementation of muxAcquire-muxRelease uses its own
4102 // dedicated Thread._MuxEvent instance. If we're interested in
4103 // minimizing the peak number of extant ParkEvent instances then
4104 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4105 // as certain invariants were satisfied. Specifically, care would need
4106 // to be taken with regards to consuming unpark() "permits".
4107 // A safe rule of thumb is that a thread would never call muxAcquire()
4108 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4109 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4110 // consume an unpark() permit intended for monitorenter, for instance.
4111 // One way around this would be to widen the restricted-range semaphore
4112 // implemented in park(). Another alternative would be to provide
4113 // multiple instances of the PlatformEvent() for each thread. One
4114 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4115 //
4116 // * Usage:
4117 // -- Only as leaf locks
4118 // -- for short-term locking only as muxAcquire does not perform
4119 // thread state transitions.
4120 //
4121 // Alternatives:
4122 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4123 // but with parking or spin-then-park instead of pure spinning.
4124 // * Use Taura-Oyama-Yonenzawa locks.
4125 // * It's possible to construct a 1-0 lock if we encode the lockword as
4126 // (List,LockByte). Acquire will CAS the full lockword while Release
4127 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4128 // acquiring threads use timers (ParkTimed) to detect and recover from
4129 // the stranding window. Thread/Node structures must be aligned on 256-byte
4130 // boundaries by using placement-new.
4131 // * Augment MCS with advisory back-link fields maintained with CAS().
4132 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4133 // The validity of the backlinks must be ratified before we trust the value.
4134 // If the backlinks are invalid the exiting thread must back-track through the
4135 // the forward links, which are always trustworthy.
4136 // * Add a successor indication. The LockWord is currently encoded as
4137 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4138 // to provide the usual futile-wakeup optimization.
4139 // See RTStt for details.
4140 // * Consider schedctl.sc_nopreempt to cover the critical section.
4141 //
4144 typedef volatile intptr_t MutexT ; // Mux Lock-word
4145 enum MuxBits { LOCKBIT = 1 } ;
4147 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4148 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4149 if (w == 0) return ;
4150 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4151 return ;
4152 }
4154 TEVENT (muxAcquire - Contention) ;
4155 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4156 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4157 for (;;) {
4158 int its = (os::is_MP() ? 100 : 0) + 1 ;
4160 // Optional spin phase: spin-then-park strategy
4161 while (--its >= 0) {
4162 w = *Lock ;
4163 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4164 return ;
4165 }
4166 }
4168 Self->reset() ;
4169 Self->OnList = intptr_t(Lock) ;
4170 // The following fence() isn't _strictly necessary as the subsequent
4171 // CAS() both serializes execution and ratifies the fetched *Lock value.
4172 OrderAccess::fence();
4173 for (;;) {
4174 w = *Lock ;
4175 if ((w & LOCKBIT) == 0) {
4176 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4177 Self->OnList = 0 ; // hygiene - allows stronger asserts
4178 return ;
4179 }
4180 continue ; // Interference -- *Lock changed -- Just retry
4181 }
4182 assert (w & LOCKBIT, "invariant") ;
4183 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4184 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4185 }
4187 while (Self->OnList != 0) {
4188 Self->park() ;
4189 }
4190 }
4191 }
4193 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4194 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4195 if (w == 0) return ;
4196 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4197 return ;
4198 }
4200 TEVENT (muxAcquire - Contention) ;
4201 ParkEvent * ReleaseAfter = NULL ;
4202 if (ev == NULL) {
4203 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4204 }
4205 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4206 for (;;) {
4207 guarantee (ev->OnList == 0, "invariant") ;
4208 int its = (os::is_MP() ? 100 : 0) + 1 ;
4210 // Optional spin phase: spin-then-park strategy
4211 while (--its >= 0) {
4212 w = *Lock ;
4213 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4214 if (ReleaseAfter != NULL) {
4215 ParkEvent::Release (ReleaseAfter) ;
4216 }
4217 return ;
4218 }
4219 }
4221 ev->reset() ;
4222 ev->OnList = intptr_t(Lock) ;
4223 // The following fence() isn't _strictly necessary as the subsequent
4224 // CAS() both serializes execution and ratifies the fetched *Lock value.
4225 OrderAccess::fence();
4226 for (;;) {
4227 w = *Lock ;
4228 if ((w & LOCKBIT) == 0) {
4229 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4230 ev->OnList = 0 ;
4231 // We call ::Release while holding the outer lock, thus
4232 // artificially lengthening the critical section.
4233 // Consider deferring the ::Release() until the subsequent unlock(),
4234 // after we've dropped the outer lock.
4235 if (ReleaseAfter != NULL) {
4236 ParkEvent::Release (ReleaseAfter) ;
4237 }
4238 return ;
4239 }
4240 continue ; // Interference -- *Lock changed -- Just retry
4241 }
4242 assert (w & LOCKBIT, "invariant") ;
4243 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4244 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4245 }
4247 while (ev->OnList != 0) {
4248 ev->park() ;
4249 }
4250 }
4251 }
4253 // Release() must extract a successor from the list and then wake that thread.
4254 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4255 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4256 // Release() would :
4257 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4258 // (B) Extract a successor from the private list "in-hand"
4259 // (C) attempt to CAS() the residual back into *Lock over null.
4260 // If there were any newly arrived threads and the CAS() would fail.
4261 // In that case Release() would detach the RATs, re-merge the list in-hand
4262 // with the RATs and repeat as needed. Alternately, Release() might
4263 // detach and extract a successor, but then pass the residual list to the wakee.
4264 // The wakee would be responsible for reattaching and remerging before it
4265 // competed for the lock.
4266 //
4267 // Both "pop" and DMR are immune from ABA corruption -- there can be
4268 // multiple concurrent pushers, but only one popper or detacher.
4269 // This implementation pops from the head of the list. This is unfair,
4270 // but tends to provide excellent throughput as hot threads remain hot.
4271 // (We wake recently run threads first).
4273 void Thread::muxRelease (volatile intptr_t * Lock) {
4274 for (;;) {
4275 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4276 assert (w & LOCKBIT, "invariant") ;
4277 if (w == LOCKBIT) return ;
4278 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4279 assert (List != NULL, "invariant") ;
4280 assert (List->OnList == intptr_t(Lock), "invariant") ;
4281 ParkEvent * nxt = List->ListNext ;
4283 // The following CAS() releases the lock and pops the head element.
4284 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4285 continue ;
4286 }
4287 List->OnList = 0 ;
4288 OrderAccess::fence() ;
4289 List->unpark () ;
4290 return ;
4291 }
4292 }
4295 void Threads::verify() {
4296 ALL_JAVA_THREADS(p) {
4297 p->verify();
4298 }
4299 VMThread* thread = VMThread::vm_thread();
4300 if (thread != NULL) thread->verify();
4301 }