Mon, 07 Jul 2014 10:12:40 +0200
8049421: G1 Class Unloading after completing a concurrent mark cycle
Reviewed-by: tschatzl, ehelin, brutisso, coleenp, roland, iveresov
Contributed-by: stefan.karlsson@oracle.com, mikael.gerdin@oracle.com
1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jvmtifiles/jvmtiEnv.hpp"
36 #include "memory/gcLocker.inline.hpp"
37 #include "memory/metaspaceShared.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "memory/universe.inline.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/objArrayOop.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/symbol.hpp"
44 #include "prims/jvm_misc.hpp"
45 #include "prims/jvmtiExport.hpp"
46 #include "prims/jvmtiThreadState.hpp"
47 #include "prims/privilegedStack.hpp"
48 #include "runtime/arguments.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/deoptimization.hpp"
51 #include "runtime/fprofiler.hpp"
52 #include "runtime/frame.inline.hpp"
53 #include "runtime/init.hpp"
54 #include "runtime/interfaceSupport.hpp"
55 #include "runtime/java.hpp"
56 #include "runtime/javaCalls.hpp"
57 #include "runtime/jniPeriodicChecker.hpp"
58 #include "runtime/memprofiler.hpp"
59 #include "runtime/mutexLocker.hpp"
60 #include "runtime/objectMonitor.hpp"
61 #include "runtime/orderAccess.inline.hpp"
62 #include "runtime/osThread.hpp"
63 #include "runtime/safepoint.hpp"
64 #include "runtime/sharedRuntime.hpp"
65 #include "runtime/statSampler.hpp"
66 #include "runtime/stubRoutines.hpp"
67 #include "runtime/task.hpp"
68 #include "runtime/thread.inline.hpp"
69 #include "runtime/threadCritical.hpp"
70 #include "runtime/threadLocalStorage.hpp"
71 #include "runtime/vframe.hpp"
72 #include "runtime/vframeArray.hpp"
73 #include "runtime/vframe_hp.hpp"
74 #include "runtime/vmThread.hpp"
75 #include "runtime/vm_operations.hpp"
76 #include "services/attachListener.hpp"
77 #include "services/management.hpp"
78 #include "services/memTracker.hpp"
79 #include "services/threadService.hpp"
80 #include "trace/tracing.hpp"
81 #include "trace/traceMacros.hpp"
82 #include "utilities/defaultStream.hpp"
83 #include "utilities/dtrace.hpp"
84 #include "utilities/events.hpp"
85 #include "utilities/preserveException.hpp"
86 #include "utilities/macros.hpp"
87 #ifdef TARGET_OS_FAMILY_linux
88 # include "os_linux.inline.hpp"
89 #endif
90 #ifdef TARGET_OS_FAMILY_solaris
91 # include "os_solaris.inline.hpp"
92 #endif
93 #ifdef TARGET_OS_FAMILY_windows
94 # include "os_windows.inline.hpp"
95 #endif
96 #ifdef TARGET_OS_FAMILY_bsd
97 # include "os_bsd.inline.hpp"
98 #endif
99 #if INCLUDE_ALL_GCS
100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
102 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
103 #endif // INCLUDE_ALL_GCS
104 #ifdef COMPILER1
105 #include "c1/c1_Compiler.hpp"
106 #endif
107 #ifdef COMPILER2
108 #include "opto/c2compiler.hpp"
109 #include "opto/idealGraphPrinter.hpp"
110 #endif
111 #if INCLUDE_RTM_OPT
112 #include "runtime/rtmLocking.hpp"
113 #endif
115 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
117 #ifdef DTRACE_ENABLED
119 // Only bother with this argument setup if dtrace is available
121 #ifndef USDT2
122 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
123 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
124 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
125 intptr_t, intptr_t, bool);
126 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
127 intptr_t, intptr_t, bool);
129 #define DTRACE_THREAD_PROBE(probe, javathread) \
130 { \
131 ResourceMark rm(this); \
132 int len = 0; \
133 const char* name = (javathread)->get_thread_name(); \
134 len = strlen(name); \
135 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
136 name, len, \
137 java_lang_Thread::thread_id((javathread)->threadObj()), \
138 (javathread)->osthread()->thread_id(), \
139 java_lang_Thread::is_daemon((javathread)->threadObj())); \
140 }
142 #else /* USDT2 */
144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
147 #define DTRACE_THREAD_PROBE(probe, javathread) \
148 { \
149 ResourceMark rm(this); \
150 int len = 0; \
151 const char* name = (javathread)->get_thread_name(); \
152 len = strlen(name); \
153 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
154 (char *) name, len, \
155 java_lang_Thread::thread_id((javathread)->threadObj()), \
156 (uintptr_t) (javathread)->osthread()->thread_id(), \
157 java_lang_Thread::is_daemon((javathread)->threadObj())); \
158 }
160 #endif /* USDT2 */
162 #else // ndef DTRACE_ENABLED
164 #define DTRACE_THREAD_PROBE(probe, javathread)
166 #endif // ndef DTRACE_ENABLED
169 // Class hierarchy
170 // - Thread
171 // - VMThread
172 // - WatcherThread
173 // - ConcurrentMarkSweepThread
174 // - JavaThread
175 // - CompilerThread
177 // ======= Thread ========
178 // Support for forcing alignment of thread objects for biased locking
179 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
180 if (UseBiasedLocking) {
181 const int alignment = markOopDesc::biased_lock_alignment;
182 size_t aligned_size = size + (alignment - sizeof(intptr_t));
183 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
184 : AllocateHeap(aligned_size, flags, CURRENT_PC,
185 AllocFailStrategy::RETURN_NULL);
186 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
187 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
188 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
189 "JavaThread alignment code overflowed allocated storage");
190 if (TraceBiasedLocking) {
191 if (aligned_addr != real_malloc_addr)
192 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
193 real_malloc_addr, aligned_addr);
194 }
195 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
196 return aligned_addr;
197 } else {
198 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
199 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
200 }
201 }
203 void Thread::operator delete(void* p) {
204 if (UseBiasedLocking) {
205 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
206 FreeHeap(real_malloc_addr, mtThread);
207 } else {
208 FreeHeap(p, mtThread);
209 }
210 }
213 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
214 // JavaThread
217 Thread::Thread() {
218 // stack and get_thread
219 set_stack_base(NULL);
220 set_stack_size(0);
221 set_self_raw_id(0);
222 set_lgrp_id(-1);
224 // allocated data structures
225 set_osthread(NULL);
226 set_resource_area(new (mtThread)ResourceArea());
227 DEBUG_ONLY(_current_resource_mark = NULL;)
228 set_handle_area(new (mtThread) HandleArea(NULL));
229 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
230 set_active_handles(NULL);
231 set_free_handle_block(NULL);
232 set_last_handle_mark(NULL);
234 // This initial value ==> never claimed.
235 _oops_do_parity = 0;
237 // the handle mark links itself to last_handle_mark
238 new HandleMark(this);
240 // plain initialization
241 debug_only(_owned_locks = NULL;)
242 debug_only(_allow_allocation_count = 0;)
243 NOT_PRODUCT(_allow_safepoint_count = 0;)
244 NOT_PRODUCT(_skip_gcalot = false;)
245 _jvmti_env_iteration_count = 0;
246 set_allocated_bytes(0);
247 _vm_operation_started_count = 0;
248 _vm_operation_completed_count = 0;
249 _current_pending_monitor = NULL;
250 _current_pending_monitor_is_from_java = true;
251 _current_waiting_monitor = NULL;
252 _num_nested_signal = 0;
253 omFreeList = NULL ;
254 omFreeCount = 0 ;
255 omFreeProvision = 32 ;
256 omInUseList = NULL ;
257 omInUseCount = 0 ;
259 #ifdef ASSERT
260 _visited_for_critical_count = false;
261 #endif
263 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
264 _suspend_flags = 0;
266 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
267 _hashStateX = os::random() ;
268 _hashStateY = 842502087 ;
269 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
270 _hashStateW = 273326509 ;
272 _OnTrap = 0 ;
273 _schedctl = NULL ;
274 _Stalled = 0 ;
275 _TypeTag = 0x2BAD ;
277 // Many of the following fields are effectively final - immutable
278 // Note that nascent threads can't use the Native Monitor-Mutex
279 // construct until the _MutexEvent is initialized ...
280 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
281 // we might instead use a stack of ParkEvents that we could provision on-demand.
282 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
283 // and ::Release()
284 _ParkEvent = ParkEvent::Allocate (this) ;
285 _SleepEvent = ParkEvent::Allocate (this) ;
286 _MutexEvent = ParkEvent::Allocate (this) ;
287 _MuxEvent = ParkEvent::Allocate (this) ;
289 #ifdef CHECK_UNHANDLED_OOPS
290 if (CheckUnhandledOops) {
291 _unhandled_oops = new UnhandledOops(this);
292 }
293 #endif // CHECK_UNHANDLED_OOPS
294 #ifdef ASSERT
295 if (UseBiasedLocking) {
296 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
297 assert(this == _real_malloc_address ||
298 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
299 "bug in forced alignment of thread objects");
300 }
301 #endif /* ASSERT */
302 }
304 void Thread::initialize_thread_local_storage() {
305 // Note: Make sure this method only calls
306 // non-blocking operations. Otherwise, it might not work
307 // with the thread-startup/safepoint interaction.
309 // During Java thread startup, safepoint code should allow this
310 // method to complete because it may need to allocate memory to
311 // store information for the new thread.
313 // initialize structure dependent on thread local storage
314 ThreadLocalStorage::set_thread(this);
315 }
317 void Thread::record_stack_base_and_size() {
318 set_stack_base(os::current_stack_base());
319 set_stack_size(os::current_stack_size());
320 if (is_Java_thread()) {
321 ((JavaThread*) this)->set_stack_overflow_limit();
322 }
323 // CR 7190089: on Solaris, primordial thread's stack is adjusted
324 // in initialize_thread(). Without the adjustment, stack size is
325 // incorrect if stack is set to unlimited (ulimit -s unlimited).
326 // So far, only Solaris has real implementation of initialize_thread().
327 //
328 // set up any platform-specific state.
329 os::initialize_thread(this);
331 #if INCLUDE_NMT
332 // record thread's native stack, stack grows downward
333 address stack_low_addr = stack_base() - stack_size();
334 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this,
335 CURRENT_PC);
336 #endif // INCLUDE_NMT
337 }
340 Thread::~Thread() {
341 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
342 ObjectSynchronizer::omFlush (this) ;
344 EVENT_THREAD_DESTRUCT(this);
346 // stack_base can be NULL if the thread is never started or exited before
347 // record_stack_base_and_size called. Although, we would like to ensure
348 // that all started threads do call record_stack_base_and_size(), there is
349 // not proper way to enforce that.
350 #if INCLUDE_NMT
351 if (_stack_base != NULL) {
352 address low_stack_addr = stack_base() - stack_size();
353 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this);
354 #ifdef ASSERT
355 set_stack_base(NULL);
356 #endif
357 }
358 #endif // INCLUDE_NMT
360 // deallocate data structures
361 delete resource_area();
362 // since the handle marks are using the handle area, we have to deallocated the root
363 // handle mark before deallocating the thread's handle area,
364 assert(last_handle_mark() != NULL, "check we have an element");
365 delete last_handle_mark();
366 assert(last_handle_mark() == NULL, "check we have reached the end");
368 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
369 // We NULL out the fields for good hygiene.
370 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
371 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
372 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
373 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
375 delete handle_area();
376 delete metadata_handles();
378 // osthread() can be NULL, if creation of thread failed.
379 if (osthread() != NULL) os::free_thread(osthread());
381 delete _SR_lock;
383 // clear thread local storage if the Thread is deleting itself
384 if (this == Thread::current()) {
385 ThreadLocalStorage::set_thread(NULL);
386 } else {
387 // In the case where we're not the current thread, invalidate all the
388 // caches in case some code tries to get the current thread or the
389 // thread that was destroyed, and gets stale information.
390 ThreadLocalStorage::invalidate_all();
391 }
392 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
393 }
395 // NOTE: dummy function for assertion purpose.
396 void Thread::run() {
397 ShouldNotReachHere();
398 }
400 #ifdef ASSERT
401 // Private method to check for dangling thread pointer
402 void check_for_dangling_thread_pointer(Thread *thread) {
403 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
404 "possibility of dangling Thread pointer");
405 }
406 #endif
409 #ifndef PRODUCT
410 // Tracing method for basic thread operations
411 void Thread::trace(const char* msg, const Thread* const thread) {
412 if (!TraceThreadEvents) return;
413 ResourceMark rm;
414 ThreadCritical tc;
415 const char *name = "non-Java thread";
416 int prio = -1;
417 if (thread->is_Java_thread()
418 && !thread->is_Compiler_thread()) {
419 // The Threads_lock must be held to get information about
420 // this thread but may not be in some situations when
421 // tracing thread events.
422 bool release_Threads_lock = false;
423 if (!Threads_lock->owned_by_self()) {
424 Threads_lock->lock();
425 release_Threads_lock = true;
426 }
427 JavaThread* jt = (JavaThread *)thread;
428 name = (char *)jt->get_thread_name();
429 oop thread_oop = jt->threadObj();
430 if (thread_oop != NULL) {
431 prio = java_lang_Thread::priority(thread_oop);
432 }
433 if (release_Threads_lock) {
434 Threads_lock->unlock();
435 }
436 }
437 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
438 }
439 #endif
442 ThreadPriority Thread::get_priority(const Thread* const thread) {
443 trace("get priority", thread);
444 ThreadPriority priority;
445 // Can return an error!
446 (void)os::get_priority(thread, priority);
447 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
448 return priority;
449 }
451 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
452 trace("set priority", thread);
453 debug_only(check_for_dangling_thread_pointer(thread);)
454 // Can return an error!
455 (void)os::set_priority(thread, priority);
456 }
459 void Thread::start(Thread* thread) {
460 trace("start", thread);
461 // Start is different from resume in that its safety is guaranteed by context or
462 // being called from a Java method synchronized on the Thread object.
463 if (!DisableStartThread) {
464 if (thread->is_Java_thread()) {
465 // Initialize the thread state to RUNNABLE before starting this thread.
466 // Can not set it after the thread started because we do not know the
467 // exact thread state at that time. It could be in MONITOR_WAIT or
468 // in SLEEPING or some other state.
469 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
470 java_lang_Thread::RUNNABLE);
471 }
472 os::start_thread(thread);
473 }
474 }
476 // Enqueue a VM_Operation to do the job for us - sometime later
477 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
478 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
479 VMThread::execute(vm_stop);
480 }
483 //
484 // Check if an external suspend request has completed (or has been
485 // cancelled). Returns true if the thread is externally suspended and
486 // false otherwise.
487 //
488 // The bits parameter returns information about the code path through
489 // the routine. Useful for debugging:
490 //
491 // set in is_ext_suspend_completed():
492 // 0x00000001 - routine was entered
493 // 0x00000010 - routine return false at end
494 // 0x00000100 - thread exited (return false)
495 // 0x00000200 - suspend request cancelled (return false)
496 // 0x00000400 - thread suspended (return true)
497 // 0x00001000 - thread is in a suspend equivalent state (return true)
498 // 0x00002000 - thread is native and walkable (return true)
499 // 0x00004000 - thread is native_trans and walkable (needed retry)
500 //
501 // set in wait_for_ext_suspend_completion():
502 // 0x00010000 - routine was entered
503 // 0x00020000 - suspend request cancelled before loop (return false)
504 // 0x00040000 - thread suspended before loop (return true)
505 // 0x00080000 - suspend request cancelled in loop (return false)
506 // 0x00100000 - thread suspended in loop (return true)
507 // 0x00200000 - suspend not completed during retry loop (return false)
508 //
510 // Helper class for tracing suspend wait debug bits.
511 //
512 // 0x00000100 indicates that the target thread exited before it could
513 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
514 // 0x00080000 each indicate a cancelled suspend request so they don't
515 // count as wait failures either.
516 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
518 class TraceSuspendDebugBits : public StackObj {
519 private:
520 JavaThread * jt;
521 bool is_wait;
522 bool called_by_wait; // meaningful when !is_wait
523 uint32_t * bits;
525 public:
526 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
527 uint32_t *_bits) {
528 jt = _jt;
529 is_wait = _is_wait;
530 called_by_wait = _called_by_wait;
531 bits = _bits;
532 }
534 ~TraceSuspendDebugBits() {
535 if (!is_wait) {
536 #if 1
537 // By default, don't trace bits for is_ext_suspend_completed() calls.
538 // That trace is very chatty.
539 return;
540 #else
541 if (!called_by_wait) {
542 // If tracing for is_ext_suspend_completed() is enabled, then only
543 // trace calls to it from wait_for_ext_suspend_completion()
544 return;
545 }
546 #endif
547 }
549 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
550 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
551 MutexLocker ml(Threads_lock); // needed for get_thread_name()
552 ResourceMark rm;
554 tty->print_cr(
555 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
556 jt->get_thread_name(), *bits);
558 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
559 }
560 }
561 }
562 };
563 #undef DEBUG_FALSE_BITS
566 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
567 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
569 bool did_trans_retry = false; // only do thread_in_native_trans retry once
570 bool do_trans_retry; // flag to force the retry
572 *bits |= 0x00000001;
574 do {
575 do_trans_retry = false;
577 if (is_exiting()) {
578 // Thread is in the process of exiting. This is always checked
579 // first to reduce the risk of dereferencing a freed JavaThread.
580 *bits |= 0x00000100;
581 return false;
582 }
584 if (!is_external_suspend()) {
585 // Suspend request is cancelled. This is always checked before
586 // is_ext_suspended() to reduce the risk of a rogue resume
587 // confusing the thread that made the suspend request.
588 *bits |= 0x00000200;
589 return false;
590 }
592 if (is_ext_suspended()) {
593 // thread is suspended
594 *bits |= 0x00000400;
595 return true;
596 }
598 // Now that we no longer do hard suspends of threads running
599 // native code, the target thread can be changing thread state
600 // while we are in this routine:
601 //
602 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
603 //
604 // We save a copy of the thread state as observed at this moment
605 // and make our decision about suspend completeness based on the
606 // copy. This closes the race where the thread state is seen as
607 // _thread_in_native_trans in the if-thread_blocked check, but is
608 // seen as _thread_blocked in if-thread_in_native_trans check.
609 JavaThreadState save_state = thread_state();
611 if (save_state == _thread_blocked && is_suspend_equivalent()) {
612 // If the thread's state is _thread_blocked and this blocking
613 // condition is known to be equivalent to a suspend, then we can
614 // consider the thread to be externally suspended. This means that
615 // the code that sets _thread_blocked has been modified to do
616 // self-suspension if the blocking condition releases. We also
617 // used to check for CONDVAR_WAIT here, but that is now covered by
618 // the _thread_blocked with self-suspension check.
619 //
620 // Return true since we wouldn't be here unless there was still an
621 // external suspend request.
622 *bits |= 0x00001000;
623 return true;
624 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
625 // Threads running native code will self-suspend on native==>VM/Java
626 // transitions. If its stack is walkable (should always be the case
627 // unless this function is called before the actual java_suspend()
628 // call), then the wait is done.
629 *bits |= 0x00002000;
630 return true;
631 } else if (!called_by_wait && !did_trans_retry &&
632 save_state == _thread_in_native_trans &&
633 frame_anchor()->walkable()) {
634 // The thread is transitioning from thread_in_native to another
635 // thread state. check_safepoint_and_suspend_for_native_trans()
636 // will force the thread to self-suspend. If it hasn't gotten
637 // there yet we may have caught the thread in-between the native
638 // code check above and the self-suspend. Lucky us. If we were
639 // called by wait_for_ext_suspend_completion(), then it
640 // will be doing the retries so we don't have to.
641 //
642 // Since we use the saved thread state in the if-statement above,
643 // there is a chance that the thread has already transitioned to
644 // _thread_blocked by the time we get here. In that case, we will
645 // make a single unnecessary pass through the logic below. This
646 // doesn't hurt anything since we still do the trans retry.
648 *bits |= 0x00004000;
650 // Once the thread leaves thread_in_native_trans for another
651 // thread state, we break out of this retry loop. We shouldn't
652 // need this flag to prevent us from getting back here, but
653 // sometimes paranoia is good.
654 did_trans_retry = true;
656 // We wait for the thread to transition to a more usable state.
657 for (int i = 1; i <= SuspendRetryCount; i++) {
658 // We used to do an "os::yield_all(i)" call here with the intention
659 // that yielding would increase on each retry. However, the parameter
660 // is ignored on Linux which means the yield didn't scale up. Waiting
661 // on the SR_lock below provides a much more predictable scale up for
662 // the delay. It also provides a simple/direct point to check for any
663 // safepoint requests from the VMThread
665 // temporarily drops SR_lock while doing wait with safepoint check
666 // (if we're a JavaThread - the WatcherThread can also call this)
667 // and increase delay with each retry
668 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
670 // check the actual thread state instead of what we saved above
671 if (thread_state() != _thread_in_native_trans) {
672 // the thread has transitioned to another thread state so
673 // try all the checks (except this one) one more time.
674 do_trans_retry = true;
675 break;
676 }
677 } // end retry loop
680 }
681 } while (do_trans_retry);
683 *bits |= 0x00000010;
684 return false;
685 }
687 //
688 // Wait for an external suspend request to complete (or be cancelled).
689 // Returns true if the thread is externally suspended and false otherwise.
690 //
691 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
692 uint32_t *bits) {
693 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
694 false /* !called_by_wait */, bits);
696 // local flag copies to minimize SR_lock hold time
697 bool is_suspended;
698 bool pending;
699 uint32_t reset_bits;
701 // set a marker so is_ext_suspend_completed() knows we are the caller
702 *bits |= 0x00010000;
704 // We use reset_bits to reinitialize the bits value at the top of
705 // each retry loop. This allows the caller to make use of any
706 // unused bits for their own marking purposes.
707 reset_bits = *bits;
709 {
710 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
711 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
712 delay, bits);
713 pending = is_external_suspend();
714 }
715 // must release SR_lock to allow suspension to complete
717 if (!pending) {
718 // A cancelled suspend request is the only false return from
719 // is_ext_suspend_completed() that keeps us from entering the
720 // retry loop.
721 *bits |= 0x00020000;
722 return false;
723 }
725 if (is_suspended) {
726 *bits |= 0x00040000;
727 return true;
728 }
730 for (int i = 1; i <= retries; i++) {
731 *bits = reset_bits; // reinit to only track last retry
733 // We used to do an "os::yield_all(i)" call here with the intention
734 // that yielding would increase on each retry. However, the parameter
735 // is ignored on Linux which means the yield didn't scale up. Waiting
736 // on the SR_lock below provides a much more predictable scale up for
737 // the delay. It also provides a simple/direct point to check for any
738 // safepoint requests from the VMThread
740 {
741 MutexLocker ml(SR_lock());
742 // wait with safepoint check (if we're a JavaThread - the WatcherThread
743 // can also call this) and increase delay with each retry
744 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
746 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
747 delay, bits);
749 // It is possible for the external suspend request to be cancelled
750 // (by a resume) before the actual suspend operation is completed.
751 // Refresh our local copy to see if we still need to wait.
752 pending = is_external_suspend();
753 }
755 if (!pending) {
756 // A cancelled suspend request is the only false return from
757 // is_ext_suspend_completed() that keeps us from staying in the
758 // retry loop.
759 *bits |= 0x00080000;
760 return false;
761 }
763 if (is_suspended) {
764 *bits |= 0x00100000;
765 return true;
766 }
767 } // end retry loop
769 // thread did not suspend after all our retries
770 *bits |= 0x00200000;
771 return false;
772 }
774 #ifndef PRODUCT
775 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
777 // This should not need to be atomic as the only way for simultaneous
778 // updates is via interrupts. Even then this should be rare or non-existant
779 // and we don't care that much anyway.
781 int index = _jmp_ring_index;
782 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
783 _jmp_ring[index]._target = (intptr_t) target;
784 _jmp_ring[index]._instruction = (intptr_t) instr;
785 _jmp_ring[index]._file = file;
786 _jmp_ring[index]._line = line;
787 }
788 #endif /* PRODUCT */
790 // Called by flat profiler
791 // Callers have already called wait_for_ext_suspend_completion
792 // The assertion for that is currently too complex to put here:
793 bool JavaThread::profile_last_Java_frame(frame* _fr) {
794 bool gotframe = false;
795 // self suspension saves needed state.
796 if (has_last_Java_frame() && _anchor.walkable()) {
797 *_fr = pd_last_frame();
798 gotframe = true;
799 }
800 return gotframe;
801 }
803 void Thread::interrupt(Thread* thread) {
804 trace("interrupt", thread);
805 debug_only(check_for_dangling_thread_pointer(thread);)
806 os::interrupt(thread);
807 }
809 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
810 trace("is_interrupted", thread);
811 debug_only(check_for_dangling_thread_pointer(thread);)
812 // Note: If clear_interrupted==false, this simply fetches and
813 // returns the value of the field osthread()->interrupted().
814 return os::is_interrupted(thread, clear_interrupted);
815 }
818 // GC Support
819 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
820 jint thread_parity = _oops_do_parity;
821 if (thread_parity != strong_roots_parity) {
822 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
823 if (res == thread_parity) {
824 return true;
825 } else {
826 guarantee(res == strong_roots_parity, "Or else what?");
827 assert(SharedHeap::heap()->workers()->active_workers() > 0,
828 "Should only fail when parallel.");
829 return false;
830 }
831 }
832 assert(SharedHeap::heap()->workers()->active_workers() > 0,
833 "Should only fail when parallel.");
834 return false;
835 }
837 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
838 active_handles()->oops_do(f);
839 // Do oop for ThreadShadow
840 f->do_oop((oop*)&_pending_exception);
841 handle_area()->oops_do(f);
842 }
844 void Thread::nmethods_do(CodeBlobClosure* cf) {
845 // no nmethods in a generic thread...
846 }
848 void Thread::metadata_do(void f(Metadata*)) {
849 if (metadata_handles() != NULL) {
850 for (int i = 0; i< metadata_handles()->length(); i++) {
851 f(metadata_handles()->at(i));
852 }
853 }
854 }
856 void Thread::print_on(outputStream* st) const {
857 // get_priority assumes osthread initialized
858 if (osthread() != NULL) {
859 int os_prio;
860 if (os::get_native_priority(this, &os_prio) == OS_OK) {
861 st->print("os_prio=%d ", os_prio);
862 }
863 st->print("tid=" INTPTR_FORMAT " ", this);
864 osthread()->print_on(st);
865 }
866 debug_only(if (WizardMode) print_owned_locks_on(st);)
867 }
869 // Thread::print_on_error() is called by fatal error handler. Don't use
870 // any lock or allocate memory.
871 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
872 if (is_VM_thread()) st->print("VMThread");
873 else if (is_Compiler_thread()) st->print("CompilerThread");
874 else if (is_Java_thread()) st->print("JavaThread");
875 else if (is_GC_task_thread()) st->print("GCTaskThread");
876 else if (is_Watcher_thread()) st->print("WatcherThread");
877 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
878 else st->print("Thread");
880 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
881 _stack_base - _stack_size, _stack_base);
883 if (osthread()) {
884 st->print(" [id=%d]", osthread()->thread_id());
885 }
886 }
888 #ifdef ASSERT
889 void Thread::print_owned_locks_on(outputStream* st) const {
890 Monitor *cur = _owned_locks;
891 if (cur == NULL) {
892 st->print(" (no locks) ");
893 } else {
894 st->print_cr(" Locks owned:");
895 while(cur) {
896 cur->print_on(st);
897 cur = cur->next();
898 }
899 }
900 }
902 static int ref_use_count = 0;
904 bool Thread::owns_locks_but_compiled_lock() const {
905 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
906 if (cur != Compile_lock) return true;
907 }
908 return false;
909 }
912 #endif
914 #ifndef PRODUCT
916 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
917 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
918 // no threads which allow_vm_block's are held
919 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
920 // Check if current thread is allowed to block at a safepoint
921 if (!(_allow_safepoint_count == 0))
922 fatal("Possible safepoint reached by thread that does not allow it");
923 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
924 fatal("LEAF method calling lock?");
925 }
927 #ifdef ASSERT
928 if (potential_vm_operation && is_Java_thread()
929 && !Universe::is_bootstrapping()) {
930 // Make sure we do not hold any locks that the VM thread also uses.
931 // This could potentially lead to deadlocks
932 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
933 // Threads_lock is special, since the safepoint synchronization will not start before this is
934 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
935 // since it is used to transfer control between JavaThreads and the VMThread
936 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
937 if ( (cur->allow_vm_block() &&
938 cur != Threads_lock &&
939 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
940 cur != VMOperationRequest_lock &&
941 cur != VMOperationQueue_lock) ||
942 cur->rank() == Mutex::special) {
943 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
944 }
945 }
946 }
948 if (GCALotAtAllSafepoints) {
949 // We could enter a safepoint here and thus have a gc
950 InterfaceSupport::check_gc_alot();
951 }
952 #endif
953 }
954 #endif
956 bool Thread::is_in_stack(address adr) const {
957 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
958 address end = os::current_stack_pointer();
959 // Allow non Java threads to call this without stack_base
960 if (_stack_base == NULL) return true;
961 if (stack_base() >= adr && adr >= end) return true;
963 return false;
964 }
967 bool Thread::is_in_usable_stack(address adr) const {
968 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
969 size_t usable_stack_size = _stack_size - stack_guard_size;
971 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
972 }
975 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
976 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
977 // used for compilation in the future. If that change is made, the need for these methods
978 // should be revisited, and they should be removed if possible.
980 bool Thread::is_lock_owned(address adr) const {
981 return on_local_stack(adr);
982 }
984 bool Thread::set_as_starting_thread() {
985 // NOTE: this must be called inside the main thread.
986 return os::create_main_thread((JavaThread*)this);
987 }
989 static void initialize_class(Symbol* class_name, TRAPS) {
990 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
991 InstanceKlass::cast(klass)->initialize(CHECK);
992 }
995 // Creates the initial ThreadGroup
996 static Handle create_initial_thread_group(TRAPS) {
997 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
998 instanceKlassHandle klass (THREAD, k);
1000 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1001 {
1002 JavaValue result(T_VOID);
1003 JavaCalls::call_special(&result,
1004 system_instance,
1005 klass,
1006 vmSymbols::object_initializer_name(),
1007 vmSymbols::void_method_signature(),
1008 CHECK_NH);
1009 }
1010 Universe::set_system_thread_group(system_instance());
1012 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1013 {
1014 JavaValue result(T_VOID);
1015 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1016 JavaCalls::call_special(&result,
1017 main_instance,
1018 klass,
1019 vmSymbols::object_initializer_name(),
1020 vmSymbols::threadgroup_string_void_signature(),
1021 system_instance,
1022 string,
1023 CHECK_NH);
1024 }
1025 return main_instance;
1026 }
1028 // Creates the initial Thread
1029 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1030 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1031 instanceKlassHandle klass (THREAD, k);
1032 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1034 java_lang_Thread::set_thread(thread_oop(), thread);
1035 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1036 thread->set_threadObj(thread_oop());
1038 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1040 JavaValue result(T_VOID);
1041 JavaCalls::call_special(&result, thread_oop,
1042 klass,
1043 vmSymbols::object_initializer_name(),
1044 vmSymbols::threadgroup_string_void_signature(),
1045 thread_group,
1046 string,
1047 CHECK_NULL);
1048 return thread_oop();
1049 }
1051 static void call_initializeSystemClass(TRAPS) {
1052 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1053 instanceKlassHandle klass (THREAD, k);
1055 JavaValue result(T_VOID);
1056 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1057 vmSymbols::void_method_signature(), CHECK);
1058 }
1060 char java_runtime_name[128] = "";
1061 char java_runtime_version[128] = "";
1063 // extract the JRE name from sun.misc.Version.java_runtime_name
1064 static const char* get_java_runtime_name(TRAPS) {
1065 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1066 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1067 fieldDescriptor fd;
1068 bool found = k != NULL &&
1069 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1070 vmSymbols::string_signature(), &fd);
1071 if (found) {
1072 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1073 if (name_oop == NULL)
1074 return NULL;
1075 const char* name = java_lang_String::as_utf8_string(name_oop,
1076 java_runtime_name,
1077 sizeof(java_runtime_name));
1078 return name;
1079 } else {
1080 return NULL;
1081 }
1082 }
1084 // extract the JRE version from sun.misc.Version.java_runtime_version
1085 static const char* get_java_runtime_version(TRAPS) {
1086 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1087 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1088 fieldDescriptor fd;
1089 bool found = k != NULL &&
1090 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1091 vmSymbols::string_signature(), &fd);
1092 if (found) {
1093 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1094 if (name_oop == NULL)
1095 return NULL;
1096 const char* name = java_lang_String::as_utf8_string(name_oop,
1097 java_runtime_version,
1098 sizeof(java_runtime_version));
1099 return name;
1100 } else {
1101 return NULL;
1102 }
1103 }
1105 // General purpose hook into Java code, run once when the VM is initialized.
1106 // The Java library method itself may be changed independently from the VM.
1107 static void call_postVMInitHook(TRAPS) {
1108 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1109 instanceKlassHandle klass (THREAD, k);
1110 if (klass.not_null()) {
1111 JavaValue result(T_VOID);
1112 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1113 vmSymbols::void_method_signature(),
1114 CHECK);
1115 }
1116 }
1118 static void reset_vm_info_property(TRAPS) {
1119 // the vm info string
1120 ResourceMark rm(THREAD);
1121 const char *vm_info = VM_Version::vm_info_string();
1123 // java.lang.System class
1124 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1125 instanceKlassHandle klass (THREAD, k);
1127 // setProperty arguments
1128 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1129 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1131 // return value
1132 JavaValue r(T_OBJECT);
1134 // public static String setProperty(String key, String value);
1135 JavaCalls::call_static(&r,
1136 klass,
1137 vmSymbols::setProperty_name(),
1138 vmSymbols::string_string_string_signature(),
1139 key_str,
1140 value_str,
1141 CHECK);
1142 }
1145 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1146 assert(thread_group.not_null(), "thread group should be specified");
1147 assert(threadObj() == NULL, "should only create Java thread object once");
1149 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1150 instanceKlassHandle klass (THREAD, k);
1151 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1153 java_lang_Thread::set_thread(thread_oop(), this);
1154 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1155 set_threadObj(thread_oop());
1157 JavaValue result(T_VOID);
1158 if (thread_name != NULL) {
1159 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1160 // Thread gets assigned specified name and null target
1161 JavaCalls::call_special(&result,
1162 thread_oop,
1163 klass,
1164 vmSymbols::object_initializer_name(),
1165 vmSymbols::threadgroup_string_void_signature(),
1166 thread_group, // Argument 1
1167 name, // Argument 2
1168 THREAD);
1169 } else {
1170 // Thread gets assigned name "Thread-nnn" and null target
1171 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1172 JavaCalls::call_special(&result,
1173 thread_oop,
1174 klass,
1175 vmSymbols::object_initializer_name(),
1176 vmSymbols::threadgroup_runnable_void_signature(),
1177 thread_group, // Argument 1
1178 Handle(), // Argument 2
1179 THREAD);
1180 }
1183 if (daemon) {
1184 java_lang_Thread::set_daemon(thread_oop());
1185 }
1187 if (HAS_PENDING_EXCEPTION) {
1188 return;
1189 }
1191 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1192 Handle threadObj(this, this->threadObj());
1194 JavaCalls::call_special(&result,
1195 thread_group,
1196 group,
1197 vmSymbols::add_method_name(),
1198 vmSymbols::thread_void_signature(),
1199 threadObj, // Arg 1
1200 THREAD);
1203 }
1205 // NamedThread -- non-JavaThread subclasses with multiple
1206 // uniquely named instances should derive from this.
1207 NamedThread::NamedThread() : Thread() {
1208 _name = NULL;
1209 _processed_thread = NULL;
1210 }
1212 NamedThread::~NamedThread() {
1213 if (_name != NULL) {
1214 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1215 _name = NULL;
1216 }
1217 }
1219 void NamedThread::set_name(const char* format, ...) {
1220 guarantee(_name == NULL, "Only get to set name once.");
1221 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1222 guarantee(_name != NULL, "alloc failure");
1223 va_list ap;
1224 va_start(ap, format);
1225 jio_vsnprintf(_name, max_name_len, format, ap);
1226 va_end(ap);
1227 }
1229 // ======= WatcherThread ========
1231 // The watcher thread exists to simulate timer interrupts. It should
1232 // be replaced by an abstraction over whatever native support for
1233 // timer interrupts exists on the platform.
1235 WatcherThread* WatcherThread::_watcher_thread = NULL;
1236 bool WatcherThread::_startable = false;
1237 volatile bool WatcherThread::_should_terminate = false;
1239 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1240 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1241 if (os::create_thread(this, os::watcher_thread)) {
1242 _watcher_thread = this;
1244 // Set the watcher thread to the highest OS priority which should not be
1245 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1246 // is created. The only normal thread using this priority is the reference
1247 // handler thread, which runs for very short intervals only.
1248 // If the VMThread's priority is not lower than the WatcherThread profiling
1249 // will be inaccurate.
1250 os::set_priority(this, MaxPriority);
1251 if (!DisableStartThread) {
1252 os::start_thread(this);
1253 }
1254 }
1255 }
1257 int WatcherThread::sleep() const {
1258 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1260 // remaining will be zero if there are no tasks,
1261 // causing the WatcherThread to sleep until a task is
1262 // enrolled
1263 int remaining = PeriodicTask::time_to_wait();
1264 int time_slept = 0;
1266 // we expect this to timeout - we only ever get unparked when
1267 // we should terminate or when a new task has been enrolled
1268 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1270 jlong time_before_loop = os::javaTimeNanos();
1272 for (;;) {
1273 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1274 jlong now = os::javaTimeNanos();
1276 if (remaining == 0) {
1277 // if we didn't have any tasks we could have waited for a long time
1278 // consider the time_slept zero and reset time_before_loop
1279 time_slept = 0;
1280 time_before_loop = now;
1281 } else {
1282 // need to recalulate since we might have new tasks in _tasks
1283 time_slept = (int) ((now - time_before_loop) / 1000000);
1284 }
1286 // Change to task list or spurious wakeup of some kind
1287 if (timedout || _should_terminate) {
1288 break;
1289 }
1291 remaining = PeriodicTask::time_to_wait();
1292 if (remaining == 0) {
1293 // Last task was just disenrolled so loop around and wait until
1294 // another task gets enrolled
1295 continue;
1296 }
1298 remaining -= time_slept;
1299 if (remaining <= 0)
1300 break;
1301 }
1303 return time_slept;
1304 }
1306 void WatcherThread::run() {
1307 assert(this == watcher_thread(), "just checking");
1309 this->record_stack_base_and_size();
1310 this->initialize_thread_local_storage();
1311 this->set_active_handles(JNIHandleBlock::allocate_block());
1312 while(!_should_terminate) {
1313 assert(watcher_thread() == Thread::current(), "thread consistency check");
1314 assert(watcher_thread() == this, "thread consistency check");
1316 // Calculate how long it'll be until the next PeriodicTask work
1317 // should be done, and sleep that amount of time.
1318 int time_waited = sleep();
1320 if (is_error_reported()) {
1321 // A fatal error has happened, the error handler(VMError::report_and_die)
1322 // should abort JVM after creating an error log file. However in some
1323 // rare cases, the error handler itself might deadlock. Here we try to
1324 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1325 //
1326 // This code is in WatcherThread because WatcherThread wakes up
1327 // periodically so the fatal error handler doesn't need to do anything;
1328 // also because the WatcherThread is less likely to crash than other
1329 // threads.
1331 for (;;) {
1332 if (!ShowMessageBoxOnError
1333 && (OnError == NULL || OnError[0] == '\0')
1334 && Arguments::abort_hook() == NULL) {
1335 os::sleep(this, 2 * 60 * 1000, false);
1336 fdStream err(defaultStream::output_fd());
1337 err.print_raw_cr("# [ timer expired, abort... ]");
1338 // skip atexit/vm_exit/vm_abort hooks
1339 os::die();
1340 }
1342 // Wake up 5 seconds later, the fatal handler may reset OnError or
1343 // ShowMessageBoxOnError when it is ready to abort.
1344 os::sleep(this, 5 * 1000, false);
1345 }
1346 }
1348 PeriodicTask::real_time_tick(time_waited);
1349 }
1351 // Signal that it is terminated
1352 {
1353 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1354 _watcher_thread = NULL;
1355 Terminator_lock->notify();
1356 }
1358 // Thread destructor usually does this..
1359 ThreadLocalStorage::set_thread(NULL);
1360 }
1362 void WatcherThread::start() {
1363 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1365 if (watcher_thread() == NULL && _startable) {
1366 _should_terminate = false;
1367 // Create the single instance of WatcherThread
1368 new WatcherThread();
1369 }
1370 }
1372 void WatcherThread::make_startable() {
1373 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1374 _startable = true;
1375 }
1377 void WatcherThread::stop() {
1378 {
1379 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1380 _should_terminate = true;
1381 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1383 WatcherThread* watcher = watcher_thread();
1384 if (watcher != NULL)
1385 watcher->unpark();
1386 }
1388 // it is ok to take late safepoints here, if needed
1389 MutexLocker mu(Terminator_lock);
1391 while(watcher_thread() != NULL) {
1392 // This wait should make safepoint checks, wait without a timeout,
1393 // and wait as a suspend-equivalent condition.
1394 //
1395 // Note: If the FlatProfiler is running, then this thread is waiting
1396 // for the WatcherThread to terminate and the WatcherThread, via the
1397 // FlatProfiler task, is waiting for the external suspend request on
1398 // this thread to complete. wait_for_ext_suspend_completion() will
1399 // eventually timeout, but that takes time. Making this wait a
1400 // suspend-equivalent condition solves that timeout problem.
1401 //
1402 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1403 Mutex::_as_suspend_equivalent_flag);
1404 }
1405 }
1407 void WatcherThread::unpark() {
1408 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1409 PeriodicTask_lock->notify();
1410 }
1412 void WatcherThread::print_on(outputStream* st) const {
1413 st->print("\"%s\" ", name());
1414 Thread::print_on(st);
1415 st->cr();
1416 }
1418 // ======= JavaThread ========
1420 // A JavaThread is a normal Java thread
1422 void JavaThread::initialize() {
1423 // Initialize fields
1425 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1426 set_claimed_par_id(UINT_MAX);
1428 set_saved_exception_pc(NULL);
1429 set_threadObj(NULL);
1430 _anchor.clear();
1431 set_entry_point(NULL);
1432 set_jni_functions(jni_functions());
1433 set_callee_target(NULL);
1434 set_vm_result(NULL);
1435 set_vm_result_2(NULL);
1436 set_vframe_array_head(NULL);
1437 set_vframe_array_last(NULL);
1438 set_deferred_locals(NULL);
1439 set_deopt_mark(NULL);
1440 set_deopt_nmethod(NULL);
1441 clear_must_deopt_id();
1442 set_monitor_chunks(NULL);
1443 set_next(NULL);
1444 set_thread_state(_thread_new);
1445 #if INCLUDE_NMT
1446 set_recorder(NULL);
1447 #endif
1448 _terminated = _not_terminated;
1449 _privileged_stack_top = NULL;
1450 _array_for_gc = NULL;
1451 _suspend_equivalent = false;
1452 _in_deopt_handler = 0;
1453 _doing_unsafe_access = false;
1454 _stack_guard_state = stack_guard_unused;
1455 (void)const_cast<oop&>(_exception_oop = NULL);
1456 _exception_pc = 0;
1457 _exception_handler_pc = 0;
1458 _is_method_handle_return = 0;
1459 _jvmti_thread_state= NULL;
1460 _should_post_on_exceptions_flag = JNI_FALSE;
1461 _jvmti_get_loaded_classes_closure = NULL;
1462 _interp_only_mode = 0;
1463 _special_runtime_exit_condition = _no_async_condition;
1464 _pending_async_exception = NULL;
1465 _thread_stat = NULL;
1466 _thread_stat = new ThreadStatistics();
1467 _blocked_on_compilation = false;
1468 _jni_active_critical = 0;
1469 _do_not_unlock_if_synchronized = false;
1470 _cached_monitor_info = NULL;
1471 _parker = Parker::Allocate(this) ;
1473 #ifndef PRODUCT
1474 _jmp_ring_index = 0;
1475 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1476 record_jump(NULL, NULL, NULL, 0);
1477 }
1478 #endif /* PRODUCT */
1480 set_thread_profiler(NULL);
1481 if (FlatProfiler::is_active()) {
1482 // This is where we would decide to either give each thread it's own profiler
1483 // or use one global one from FlatProfiler,
1484 // or up to some count of the number of profiled threads, etc.
1485 ThreadProfiler* pp = new ThreadProfiler();
1486 pp->engage();
1487 set_thread_profiler(pp);
1488 }
1490 // Setup safepoint state info for this thread
1491 ThreadSafepointState::create(this);
1493 debug_only(_java_call_counter = 0);
1495 // JVMTI PopFrame support
1496 _popframe_condition = popframe_inactive;
1497 _popframe_preserved_args = NULL;
1498 _popframe_preserved_args_size = 0;
1500 pd_initialize();
1501 }
1503 #if INCLUDE_ALL_GCS
1504 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1505 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1506 #endif // INCLUDE_ALL_GCS
1508 JavaThread::JavaThread(bool is_attaching_via_jni) :
1509 Thread()
1510 #if INCLUDE_ALL_GCS
1511 , _satb_mark_queue(&_satb_mark_queue_set),
1512 _dirty_card_queue(&_dirty_card_queue_set)
1513 #endif // INCLUDE_ALL_GCS
1514 {
1515 initialize();
1516 if (is_attaching_via_jni) {
1517 _jni_attach_state = _attaching_via_jni;
1518 } else {
1519 _jni_attach_state = _not_attaching_via_jni;
1520 }
1521 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1522 _safepoint_visible = false;
1523 }
1525 bool JavaThread::reguard_stack(address cur_sp) {
1526 if (_stack_guard_state != stack_guard_yellow_disabled) {
1527 return true; // Stack already guarded or guard pages not needed.
1528 }
1530 if (register_stack_overflow()) {
1531 // For those architectures which have separate register and
1532 // memory stacks, we must check the register stack to see if
1533 // it has overflowed.
1534 return false;
1535 }
1537 // Java code never executes within the yellow zone: the latter is only
1538 // there to provoke an exception during stack banging. If java code
1539 // is executing there, either StackShadowPages should be larger, or
1540 // some exception code in c1, c2 or the interpreter isn't unwinding
1541 // when it should.
1542 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1544 enable_stack_yellow_zone();
1545 return true;
1546 }
1548 bool JavaThread::reguard_stack(void) {
1549 return reguard_stack(os::current_stack_pointer());
1550 }
1553 void JavaThread::block_if_vm_exited() {
1554 if (_terminated == _vm_exited) {
1555 // _vm_exited is set at safepoint, and Threads_lock is never released
1556 // we will block here forever
1557 Threads_lock->lock_without_safepoint_check();
1558 ShouldNotReachHere();
1559 }
1560 }
1563 // Remove this ifdef when C1 is ported to the compiler interface.
1564 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1566 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1567 Thread()
1568 #if INCLUDE_ALL_GCS
1569 , _satb_mark_queue(&_satb_mark_queue_set),
1570 _dirty_card_queue(&_dirty_card_queue_set)
1571 #endif // INCLUDE_ALL_GCS
1572 {
1573 if (TraceThreadEvents) {
1574 tty->print_cr("creating thread %p", this);
1575 }
1576 initialize();
1577 _jni_attach_state = _not_attaching_via_jni;
1578 set_entry_point(entry_point);
1579 // Create the native thread itself.
1580 // %note runtime_23
1581 os::ThreadType thr_type = os::java_thread;
1582 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1583 os::java_thread;
1584 os::create_thread(this, thr_type, stack_sz);
1585 _safepoint_visible = false;
1586 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1587 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1588 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1589 // the exception consists of creating the exception object & initializing it, initialization
1590 // will leave the VM via a JavaCall and then all locks must be unlocked).
1591 //
1592 // The thread is still suspended when we reach here. Thread must be explicit started
1593 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1594 // by calling Threads:add. The reason why this is not done here, is because the thread
1595 // object must be fully initialized (take a look at JVM_Start)
1596 }
1598 JavaThread::~JavaThread() {
1599 if (TraceThreadEvents) {
1600 tty->print_cr("terminate thread %p", this);
1601 }
1603 // By now, this thread should already be invisible to safepoint,
1604 // and its per-thread recorder also collected.
1605 assert(!is_safepoint_visible(), "wrong state");
1606 #if INCLUDE_NMT
1607 assert(get_recorder() == NULL, "Already collected");
1608 #endif // INCLUDE_NMT
1610 // JSR166 -- return the parker to the free list
1611 Parker::Release(_parker);
1612 _parker = NULL ;
1614 // Free any remaining previous UnrollBlock
1615 vframeArray* old_array = vframe_array_last();
1617 if (old_array != NULL) {
1618 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1619 old_array->set_unroll_block(NULL);
1620 delete old_info;
1621 delete old_array;
1622 }
1624 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1625 if (deferred != NULL) {
1626 // This can only happen if thread is destroyed before deoptimization occurs.
1627 assert(deferred->length() != 0, "empty array!");
1628 do {
1629 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1630 deferred->remove_at(0);
1631 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1632 delete dlv;
1633 } while (deferred->length() != 0);
1634 delete deferred;
1635 }
1637 // All Java related clean up happens in exit
1638 ThreadSafepointState::destroy(this);
1639 if (_thread_profiler != NULL) delete _thread_profiler;
1640 if (_thread_stat != NULL) delete _thread_stat;
1641 }
1644 // The first routine called by a new Java thread
1645 void JavaThread::run() {
1646 // initialize thread-local alloc buffer related fields
1647 this->initialize_tlab();
1649 // used to test validitity of stack trace backs
1650 this->record_base_of_stack_pointer();
1652 // Record real stack base and size.
1653 this->record_stack_base_and_size();
1655 // Initialize thread local storage; set before calling MutexLocker
1656 this->initialize_thread_local_storage();
1658 this->create_stack_guard_pages();
1660 this->cache_global_variables();
1662 // Thread is now sufficient initialized to be handled by the safepoint code as being
1663 // in the VM. Change thread state from _thread_new to _thread_in_vm
1664 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1666 assert(JavaThread::current() == this, "sanity check");
1667 assert(!Thread::current()->owns_locks(), "sanity check");
1669 DTRACE_THREAD_PROBE(start, this);
1671 // This operation might block. We call that after all safepoint checks for a new thread has
1672 // been completed.
1673 this->set_active_handles(JNIHandleBlock::allocate_block());
1675 if (JvmtiExport::should_post_thread_life()) {
1676 JvmtiExport::post_thread_start(this);
1677 }
1679 EventThreadStart event;
1680 if (event.should_commit()) {
1681 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1682 event.commit();
1683 }
1685 // We call another function to do the rest so we are sure that the stack addresses used
1686 // from there will be lower than the stack base just computed
1687 thread_main_inner();
1689 // Note, thread is no longer valid at this point!
1690 }
1693 void JavaThread::thread_main_inner() {
1694 assert(JavaThread::current() == this, "sanity check");
1695 assert(this->threadObj() != NULL, "just checking");
1697 // Execute thread entry point unless this thread has a pending exception
1698 // or has been stopped before starting.
1699 // Note: Due to JVM_StopThread we can have pending exceptions already!
1700 if (!this->has_pending_exception() &&
1701 !java_lang_Thread::is_stillborn(this->threadObj())) {
1702 {
1703 ResourceMark rm(this);
1704 this->set_native_thread_name(this->get_thread_name());
1705 }
1706 HandleMark hm(this);
1707 this->entry_point()(this, this);
1708 }
1710 DTRACE_THREAD_PROBE(stop, this);
1712 this->exit(false);
1713 delete this;
1714 }
1717 static void ensure_join(JavaThread* thread) {
1718 // We do not need to grap the Threads_lock, since we are operating on ourself.
1719 Handle threadObj(thread, thread->threadObj());
1720 assert(threadObj.not_null(), "java thread object must exist");
1721 ObjectLocker lock(threadObj, thread);
1722 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1723 thread->clear_pending_exception();
1724 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1725 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1726 // Clear the native thread instance - this makes isAlive return false and allows the join()
1727 // to complete once we've done the notify_all below
1728 java_lang_Thread::set_thread(threadObj(), NULL);
1729 lock.notify_all(thread);
1730 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1731 thread->clear_pending_exception();
1732 }
1735 // For any new cleanup additions, please check to see if they need to be applied to
1736 // cleanup_failed_attach_current_thread as well.
1737 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1738 assert(this == JavaThread::current(), "thread consistency check");
1740 HandleMark hm(this);
1741 Handle uncaught_exception(this, this->pending_exception());
1742 this->clear_pending_exception();
1743 Handle threadObj(this, this->threadObj());
1744 assert(threadObj.not_null(), "Java thread object should be created");
1746 if (get_thread_profiler() != NULL) {
1747 get_thread_profiler()->disengage();
1748 ResourceMark rm;
1749 get_thread_profiler()->print(get_thread_name());
1750 }
1753 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1754 {
1755 EXCEPTION_MARK;
1757 CLEAR_PENDING_EXCEPTION;
1758 }
1759 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1760 // has to be fixed by a runtime query method
1761 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1762 // JSR-166: change call from from ThreadGroup.uncaughtException to
1763 // java.lang.Thread.dispatchUncaughtException
1764 if (uncaught_exception.not_null()) {
1765 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1766 {
1767 EXCEPTION_MARK;
1768 // Check if the method Thread.dispatchUncaughtException() exists. If so
1769 // call it. Otherwise we have an older library without the JSR-166 changes,
1770 // so call ThreadGroup.uncaughtException()
1771 KlassHandle recvrKlass(THREAD, threadObj->klass());
1772 CallInfo callinfo;
1773 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1774 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1775 vmSymbols::dispatchUncaughtException_name(),
1776 vmSymbols::throwable_void_signature(),
1777 KlassHandle(), false, false, THREAD);
1778 CLEAR_PENDING_EXCEPTION;
1779 methodHandle method = callinfo.selected_method();
1780 if (method.not_null()) {
1781 JavaValue result(T_VOID);
1782 JavaCalls::call_virtual(&result,
1783 threadObj, thread_klass,
1784 vmSymbols::dispatchUncaughtException_name(),
1785 vmSymbols::throwable_void_signature(),
1786 uncaught_exception,
1787 THREAD);
1788 } else {
1789 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1790 JavaValue result(T_VOID);
1791 JavaCalls::call_virtual(&result,
1792 group, thread_group,
1793 vmSymbols::uncaughtException_name(),
1794 vmSymbols::thread_throwable_void_signature(),
1795 threadObj, // Arg 1
1796 uncaught_exception, // Arg 2
1797 THREAD);
1798 }
1799 if (HAS_PENDING_EXCEPTION) {
1800 ResourceMark rm(this);
1801 jio_fprintf(defaultStream::error_stream(),
1802 "\nException: %s thrown from the UncaughtExceptionHandler"
1803 " in thread \"%s\"\n",
1804 pending_exception()->klass()->external_name(),
1805 get_thread_name());
1806 CLEAR_PENDING_EXCEPTION;
1807 }
1808 }
1809 }
1811 // Called before the java thread exit since we want to read info
1812 // from java_lang_Thread object
1813 EventThreadEnd event;
1814 if (event.should_commit()) {
1815 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1816 event.commit();
1817 }
1819 // Call after last event on thread
1820 EVENT_THREAD_EXIT(this);
1822 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1823 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1824 // is deprecated anyhow.
1825 if (!is_Compiler_thread()) {
1826 int count = 3;
1827 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1828 EXCEPTION_MARK;
1829 JavaValue result(T_VOID);
1830 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1831 JavaCalls::call_virtual(&result,
1832 threadObj, thread_klass,
1833 vmSymbols::exit_method_name(),
1834 vmSymbols::void_method_signature(),
1835 THREAD);
1836 CLEAR_PENDING_EXCEPTION;
1837 }
1838 }
1839 // notify JVMTI
1840 if (JvmtiExport::should_post_thread_life()) {
1841 JvmtiExport::post_thread_end(this);
1842 }
1844 // We have notified the agents that we are exiting, before we go on,
1845 // we must check for a pending external suspend request and honor it
1846 // in order to not surprise the thread that made the suspend request.
1847 while (true) {
1848 {
1849 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1850 if (!is_external_suspend()) {
1851 set_terminated(_thread_exiting);
1852 ThreadService::current_thread_exiting(this);
1853 break;
1854 }
1855 // Implied else:
1856 // Things get a little tricky here. We have a pending external
1857 // suspend request, but we are holding the SR_lock so we
1858 // can't just self-suspend. So we temporarily drop the lock
1859 // and then self-suspend.
1860 }
1862 ThreadBlockInVM tbivm(this);
1863 java_suspend_self();
1865 // We're done with this suspend request, but we have to loop around
1866 // and check again. Eventually we will get SR_lock without a pending
1867 // external suspend request and will be able to mark ourselves as
1868 // exiting.
1869 }
1870 // no more external suspends are allowed at this point
1871 } else {
1872 // before_exit() has already posted JVMTI THREAD_END events
1873 }
1875 // Notify waiters on thread object. This has to be done after exit() is called
1876 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1877 // group should have the destroyed bit set before waiters are notified).
1878 ensure_join(this);
1879 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1881 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1882 // held by this thread must be released. A detach operation must only
1883 // get here if there are no Java frames on the stack. Therefore, any
1884 // owned monitors at this point MUST be JNI-acquired monitors which are
1885 // pre-inflated and in the monitor cache.
1886 //
1887 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1888 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1889 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1890 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1891 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1892 }
1894 // These things needs to be done while we are still a Java Thread. Make sure that thread
1895 // is in a consistent state, in case GC happens
1896 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1898 if (active_handles() != NULL) {
1899 JNIHandleBlock* block = active_handles();
1900 set_active_handles(NULL);
1901 JNIHandleBlock::release_block(block);
1902 }
1904 if (free_handle_block() != NULL) {
1905 JNIHandleBlock* block = free_handle_block();
1906 set_free_handle_block(NULL);
1907 JNIHandleBlock::release_block(block);
1908 }
1910 // These have to be removed while this is still a valid thread.
1911 remove_stack_guard_pages();
1913 if (UseTLAB) {
1914 tlab().make_parsable(true); // retire TLAB
1915 }
1917 if (JvmtiEnv::environments_might_exist()) {
1918 JvmtiExport::cleanup_thread(this);
1919 }
1921 // We must flush any deferred card marks before removing a thread from
1922 // the list of active threads.
1923 Universe::heap()->flush_deferred_store_barrier(this);
1924 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1926 #if INCLUDE_ALL_GCS
1927 // We must flush the G1-related buffers before removing a thread
1928 // from the list of active threads. We must do this after any deferred
1929 // card marks have been flushed (above) so that any entries that are
1930 // added to the thread's dirty card queue as a result are not lost.
1931 if (UseG1GC) {
1932 flush_barrier_queues();
1933 }
1934 #endif // INCLUDE_ALL_GCS
1936 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1937 Threads::remove(this);
1938 }
1940 #if INCLUDE_ALL_GCS
1941 // Flush G1-related queues.
1942 void JavaThread::flush_barrier_queues() {
1943 satb_mark_queue().flush();
1944 dirty_card_queue().flush();
1945 }
1947 void JavaThread::initialize_queues() {
1948 assert(!SafepointSynchronize::is_at_safepoint(),
1949 "we should not be at a safepoint");
1951 ObjPtrQueue& satb_queue = satb_mark_queue();
1952 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1953 // The SATB queue should have been constructed with its active
1954 // field set to false.
1955 assert(!satb_queue.is_active(), "SATB queue should not be active");
1956 assert(satb_queue.is_empty(), "SATB queue should be empty");
1957 // If we are creating the thread during a marking cycle, we should
1958 // set the active field of the SATB queue to true.
1959 if (satb_queue_set.is_active()) {
1960 satb_queue.set_active(true);
1961 }
1963 DirtyCardQueue& dirty_queue = dirty_card_queue();
1964 // The dirty card queue should have been constructed with its
1965 // active field set to true.
1966 assert(dirty_queue.is_active(), "dirty card queue should be active");
1967 }
1968 #endif // INCLUDE_ALL_GCS
1970 void JavaThread::cleanup_failed_attach_current_thread() {
1971 if (get_thread_profiler() != NULL) {
1972 get_thread_profiler()->disengage();
1973 ResourceMark rm;
1974 get_thread_profiler()->print(get_thread_name());
1975 }
1977 if (active_handles() != NULL) {
1978 JNIHandleBlock* block = active_handles();
1979 set_active_handles(NULL);
1980 JNIHandleBlock::release_block(block);
1981 }
1983 if (free_handle_block() != NULL) {
1984 JNIHandleBlock* block = free_handle_block();
1985 set_free_handle_block(NULL);
1986 JNIHandleBlock::release_block(block);
1987 }
1989 // These have to be removed while this is still a valid thread.
1990 remove_stack_guard_pages();
1992 if (UseTLAB) {
1993 tlab().make_parsable(true); // retire TLAB, if any
1994 }
1996 #if INCLUDE_ALL_GCS
1997 if (UseG1GC) {
1998 flush_barrier_queues();
1999 }
2000 #endif // INCLUDE_ALL_GCS
2002 Threads::remove(this);
2003 delete this;
2004 }
2009 JavaThread* JavaThread::active() {
2010 Thread* thread = ThreadLocalStorage::thread();
2011 assert(thread != NULL, "just checking");
2012 if (thread->is_Java_thread()) {
2013 return (JavaThread*) thread;
2014 } else {
2015 assert(thread->is_VM_thread(), "this must be a vm thread");
2016 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2017 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2018 assert(ret->is_Java_thread(), "must be a Java thread");
2019 return ret;
2020 }
2021 }
2023 bool JavaThread::is_lock_owned(address adr) const {
2024 if (Thread::is_lock_owned(adr)) return true;
2026 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2027 if (chunk->contains(adr)) return true;
2028 }
2030 return false;
2031 }
2034 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2035 chunk->set_next(monitor_chunks());
2036 set_monitor_chunks(chunk);
2037 }
2039 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2040 guarantee(monitor_chunks() != NULL, "must be non empty");
2041 if (monitor_chunks() == chunk) {
2042 set_monitor_chunks(chunk->next());
2043 } else {
2044 MonitorChunk* prev = monitor_chunks();
2045 while (prev->next() != chunk) prev = prev->next();
2046 prev->set_next(chunk->next());
2047 }
2048 }
2050 // JVM support.
2052 // Note: this function shouldn't block if it's called in
2053 // _thread_in_native_trans state (such as from
2054 // check_special_condition_for_native_trans()).
2055 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2057 if (has_last_Java_frame() && has_async_condition()) {
2058 // If we are at a polling page safepoint (not a poll return)
2059 // then we must defer async exception because live registers
2060 // will be clobbered by the exception path. Poll return is
2061 // ok because the call we a returning from already collides
2062 // with exception handling registers and so there is no issue.
2063 // (The exception handling path kills call result registers but
2064 // this is ok since the exception kills the result anyway).
2066 if (is_at_poll_safepoint()) {
2067 // if the code we are returning to has deoptimized we must defer
2068 // the exception otherwise live registers get clobbered on the
2069 // exception path before deoptimization is able to retrieve them.
2070 //
2071 RegisterMap map(this, false);
2072 frame caller_fr = last_frame().sender(&map);
2073 assert(caller_fr.is_compiled_frame(), "what?");
2074 if (caller_fr.is_deoptimized_frame()) {
2075 if (TraceExceptions) {
2076 ResourceMark rm;
2077 tty->print_cr("deferred async exception at compiled safepoint");
2078 }
2079 return;
2080 }
2081 }
2082 }
2084 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2085 if (condition == _no_async_condition) {
2086 // Conditions have changed since has_special_runtime_exit_condition()
2087 // was called:
2088 // - if we were here only because of an external suspend request,
2089 // then that was taken care of above (or cancelled) so we are done
2090 // - if we were here because of another async request, then it has
2091 // been cleared between the has_special_runtime_exit_condition()
2092 // and now so again we are done
2093 return;
2094 }
2096 // Check for pending async. exception
2097 if (_pending_async_exception != NULL) {
2098 // Only overwrite an already pending exception, if it is not a threadDeath.
2099 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2101 // We cannot call Exceptions::_throw(...) here because we cannot block
2102 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2104 if (TraceExceptions) {
2105 ResourceMark rm;
2106 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2107 if (has_last_Java_frame() ) {
2108 frame f = last_frame();
2109 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2110 }
2111 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2112 }
2113 _pending_async_exception = NULL;
2114 clear_has_async_exception();
2115 }
2116 }
2118 if (check_unsafe_error &&
2119 condition == _async_unsafe_access_error && !has_pending_exception()) {
2120 condition = _no_async_condition; // done
2121 switch (thread_state()) {
2122 case _thread_in_vm:
2123 {
2124 JavaThread* THREAD = this;
2125 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2126 }
2127 case _thread_in_native:
2128 {
2129 ThreadInVMfromNative tiv(this);
2130 JavaThread* THREAD = this;
2131 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2132 }
2133 case _thread_in_Java:
2134 {
2135 ThreadInVMfromJava tiv(this);
2136 JavaThread* THREAD = this;
2137 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2138 }
2139 default:
2140 ShouldNotReachHere();
2141 }
2142 }
2144 assert(condition == _no_async_condition || has_pending_exception() ||
2145 (!check_unsafe_error && condition == _async_unsafe_access_error),
2146 "must have handled the async condition, if no exception");
2147 }
2149 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2150 //
2151 // Check for pending external suspend. Internal suspend requests do
2152 // not use handle_special_runtime_exit_condition().
2153 // If JNIEnv proxies are allowed, don't self-suspend if the target
2154 // thread is not the current thread. In older versions of jdbx, jdbx
2155 // threads could call into the VM with another thread's JNIEnv so we
2156 // can be here operating on behalf of a suspended thread (4432884).
2157 bool do_self_suspend = is_external_suspend_with_lock();
2158 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2159 //
2160 // Because thread is external suspended the safepoint code will count
2161 // thread as at a safepoint. This can be odd because we can be here
2162 // as _thread_in_Java which would normally transition to _thread_blocked
2163 // at a safepoint. We would like to mark the thread as _thread_blocked
2164 // before calling java_suspend_self like all other callers of it but
2165 // we must then observe proper safepoint protocol. (We can't leave
2166 // _thread_blocked with a safepoint in progress). However we can be
2167 // here as _thread_in_native_trans so we can't use a normal transition
2168 // constructor/destructor pair because they assert on that type of
2169 // transition. We could do something like:
2170 //
2171 // JavaThreadState state = thread_state();
2172 // set_thread_state(_thread_in_vm);
2173 // {
2174 // ThreadBlockInVM tbivm(this);
2175 // java_suspend_self()
2176 // }
2177 // set_thread_state(_thread_in_vm_trans);
2178 // if (safepoint) block;
2179 // set_thread_state(state);
2180 //
2181 // but that is pretty messy. Instead we just go with the way the
2182 // code has worked before and note that this is the only path to
2183 // java_suspend_self that doesn't put the thread in _thread_blocked
2184 // mode.
2186 frame_anchor()->make_walkable(this);
2187 java_suspend_self();
2189 // We might be here for reasons in addition to the self-suspend request
2190 // so check for other async requests.
2191 }
2193 if (check_asyncs) {
2194 check_and_handle_async_exceptions();
2195 }
2196 }
2198 void JavaThread::send_thread_stop(oop java_throwable) {
2199 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2200 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2201 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2203 // Do not throw asynchronous exceptions against the compiler thread
2204 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2205 if (is_Compiler_thread()) return;
2207 {
2208 // Actually throw the Throwable against the target Thread - however
2209 // only if there is no thread death exception installed already.
2210 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2211 // If the topmost frame is a runtime stub, then we are calling into
2212 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2213 // must deoptimize the caller before continuing, as the compiled exception handler table
2214 // may not be valid
2215 if (has_last_Java_frame()) {
2216 frame f = last_frame();
2217 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2218 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2219 RegisterMap reg_map(this, UseBiasedLocking);
2220 frame compiled_frame = f.sender(®_map);
2221 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2222 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2223 }
2224 }
2225 }
2227 // Set async. pending exception in thread.
2228 set_pending_async_exception(java_throwable);
2230 if (TraceExceptions) {
2231 ResourceMark rm;
2232 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2233 }
2234 // for AbortVMOnException flag
2235 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2236 }
2237 }
2240 // Interrupt thread so it will wake up from a potential wait()
2241 Thread::interrupt(this);
2242 }
2244 // External suspension mechanism.
2245 //
2246 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2247 // to any VM_locks and it is at a transition
2248 // Self-suspension will happen on the transition out of the vm.
2249 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2250 //
2251 // Guarantees on return:
2252 // + Target thread will not execute any new bytecode (that's why we need to
2253 // force a safepoint)
2254 // + Target thread will not enter any new monitors
2255 //
2256 void JavaThread::java_suspend() {
2257 { MutexLocker mu(Threads_lock);
2258 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2259 return;
2260 }
2261 }
2263 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2264 if (!is_external_suspend()) {
2265 // a racing resume has cancelled us; bail out now
2266 return;
2267 }
2269 // suspend is done
2270 uint32_t debug_bits = 0;
2271 // Warning: is_ext_suspend_completed() may temporarily drop the
2272 // SR_lock to allow the thread to reach a stable thread state if
2273 // it is currently in a transient thread state.
2274 if (is_ext_suspend_completed(false /* !called_by_wait */,
2275 SuspendRetryDelay, &debug_bits) ) {
2276 return;
2277 }
2278 }
2280 VM_ForceSafepoint vm_suspend;
2281 VMThread::execute(&vm_suspend);
2282 }
2284 // Part II of external suspension.
2285 // A JavaThread self suspends when it detects a pending external suspend
2286 // request. This is usually on transitions. It is also done in places
2287 // where continuing to the next transition would surprise the caller,
2288 // e.g., monitor entry.
2289 //
2290 // Returns the number of times that the thread self-suspended.
2291 //
2292 // Note: DO NOT call java_suspend_self() when you just want to block current
2293 // thread. java_suspend_self() is the second stage of cooperative
2294 // suspension for external suspend requests and should only be used
2295 // to complete an external suspend request.
2296 //
2297 int JavaThread::java_suspend_self() {
2298 int ret = 0;
2300 // we are in the process of exiting so don't suspend
2301 if (is_exiting()) {
2302 clear_external_suspend();
2303 return ret;
2304 }
2306 assert(_anchor.walkable() ||
2307 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2308 "must have walkable stack");
2310 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2312 assert(!this->is_ext_suspended(),
2313 "a thread trying to self-suspend should not already be suspended");
2315 if (this->is_suspend_equivalent()) {
2316 // If we are self-suspending as a result of the lifting of a
2317 // suspend equivalent condition, then the suspend_equivalent
2318 // flag is not cleared until we set the ext_suspended flag so
2319 // that wait_for_ext_suspend_completion() returns consistent
2320 // results.
2321 this->clear_suspend_equivalent();
2322 }
2324 // A racing resume may have cancelled us before we grabbed SR_lock
2325 // above. Or another external suspend request could be waiting for us
2326 // by the time we return from SR_lock()->wait(). The thread
2327 // that requested the suspension may already be trying to walk our
2328 // stack and if we return now, we can change the stack out from under
2329 // it. This would be a "bad thing (TM)" and cause the stack walker
2330 // to crash. We stay self-suspended until there are no more pending
2331 // external suspend requests.
2332 while (is_external_suspend()) {
2333 ret++;
2334 this->set_ext_suspended();
2336 // _ext_suspended flag is cleared by java_resume()
2337 while (is_ext_suspended()) {
2338 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2339 }
2340 }
2342 return ret;
2343 }
2345 #ifdef ASSERT
2346 // verify the JavaThread has not yet been published in the Threads::list, and
2347 // hence doesn't need protection from concurrent access at this stage
2348 void JavaThread::verify_not_published() {
2349 if (!Threads_lock->owned_by_self()) {
2350 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2351 assert( !Threads::includes(this),
2352 "java thread shouldn't have been published yet!");
2353 }
2354 else {
2355 assert( !Threads::includes(this),
2356 "java thread shouldn't have been published yet!");
2357 }
2358 }
2359 #endif
2361 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2362 // progress or when _suspend_flags is non-zero.
2363 // Current thread needs to self-suspend if there is a suspend request and/or
2364 // block if a safepoint is in progress.
2365 // Async exception ISN'T checked.
2366 // Note only the ThreadInVMfromNative transition can call this function
2367 // directly and when thread state is _thread_in_native_trans
2368 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2369 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2371 JavaThread *curJT = JavaThread::current();
2372 bool do_self_suspend = thread->is_external_suspend();
2374 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2376 // If JNIEnv proxies are allowed, don't self-suspend if the target
2377 // thread is not the current thread. In older versions of jdbx, jdbx
2378 // threads could call into the VM with another thread's JNIEnv so we
2379 // can be here operating on behalf of a suspended thread (4432884).
2380 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2381 JavaThreadState state = thread->thread_state();
2383 // We mark this thread_blocked state as a suspend-equivalent so
2384 // that a caller to is_ext_suspend_completed() won't be confused.
2385 // The suspend-equivalent state is cleared by java_suspend_self().
2386 thread->set_suspend_equivalent();
2388 // If the safepoint code sees the _thread_in_native_trans state, it will
2389 // wait until the thread changes to other thread state. There is no
2390 // guarantee on how soon we can obtain the SR_lock and complete the
2391 // self-suspend request. It would be a bad idea to let safepoint wait for
2392 // too long. Temporarily change the state to _thread_blocked to
2393 // let the VM thread know that this thread is ready for GC. The problem
2394 // of changing thread state is that safepoint could happen just after
2395 // java_suspend_self() returns after being resumed, and VM thread will
2396 // see the _thread_blocked state. We must check for safepoint
2397 // after restoring the state and make sure we won't leave while a safepoint
2398 // is in progress.
2399 thread->set_thread_state(_thread_blocked);
2400 thread->java_suspend_self();
2401 thread->set_thread_state(state);
2402 // Make sure new state is seen by VM thread
2403 if (os::is_MP()) {
2404 if (UseMembar) {
2405 // Force a fence between the write above and read below
2406 OrderAccess::fence();
2407 } else {
2408 // Must use this rather than serialization page in particular on Windows
2409 InterfaceSupport::serialize_memory(thread);
2410 }
2411 }
2412 }
2414 if (SafepointSynchronize::do_call_back()) {
2415 // If we are safepointing, then block the caller which may not be
2416 // the same as the target thread (see above).
2417 SafepointSynchronize::block(curJT);
2418 }
2420 if (thread->is_deopt_suspend()) {
2421 thread->clear_deopt_suspend();
2422 RegisterMap map(thread, false);
2423 frame f = thread->last_frame();
2424 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2425 f = f.sender(&map);
2426 }
2427 if (f.id() == thread->must_deopt_id()) {
2428 thread->clear_must_deopt_id();
2429 f.deoptimize(thread);
2430 } else {
2431 fatal("missed deoptimization!");
2432 }
2433 }
2434 }
2436 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2437 // progress or when _suspend_flags is non-zero.
2438 // Current thread needs to self-suspend if there is a suspend request and/or
2439 // block if a safepoint is in progress.
2440 // Also check for pending async exception (not including unsafe access error).
2441 // Note only the native==>VM/Java barriers can call this function and when
2442 // thread state is _thread_in_native_trans.
2443 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2444 check_safepoint_and_suspend_for_native_trans(thread);
2446 if (thread->has_async_exception()) {
2447 // We are in _thread_in_native_trans state, don't handle unsafe
2448 // access error since that may block.
2449 thread->check_and_handle_async_exceptions(false);
2450 }
2451 }
2453 // This is a variant of the normal
2454 // check_special_condition_for_native_trans with slightly different
2455 // semantics for use by critical native wrappers. It does all the
2456 // normal checks but also performs the transition back into
2457 // thread_in_Java state. This is required so that critical natives
2458 // can potentially block and perform a GC if they are the last thread
2459 // exiting the GC_locker.
2460 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2461 check_special_condition_for_native_trans(thread);
2463 // Finish the transition
2464 thread->set_thread_state(_thread_in_Java);
2466 if (thread->do_critical_native_unlock()) {
2467 ThreadInVMfromJavaNoAsyncException tiv(thread);
2468 GC_locker::unlock_critical(thread);
2469 thread->clear_critical_native_unlock();
2470 }
2471 }
2473 // We need to guarantee the Threads_lock here, since resumes are not
2474 // allowed during safepoint synchronization
2475 // Can only resume from an external suspension
2476 void JavaThread::java_resume() {
2477 assert_locked_or_safepoint(Threads_lock);
2479 // Sanity check: thread is gone, has started exiting or the thread
2480 // was not externally suspended.
2481 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2482 return;
2483 }
2485 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2487 clear_external_suspend();
2489 if (is_ext_suspended()) {
2490 clear_ext_suspended();
2491 SR_lock()->notify_all();
2492 }
2493 }
2495 void JavaThread::create_stack_guard_pages() {
2496 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2497 address low_addr = stack_base() - stack_size();
2498 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2500 int allocate = os::allocate_stack_guard_pages();
2501 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2503 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2504 warning("Attempt to allocate stack guard pages failed.");
2505 return;
2506 }
2508 if (os::guard_memory((char *) low_addr, len)) {
2509 _stack_guard_state = stack_guard_enabled;
2510 } else {
2511 warning("Attempt to protect stack guard pages failed.");
2512 if (os::uncommit_memory((char *) low_addr, len)) {
2513 warning("Attempt to deallocate stack guard pages failed.");
2514 }
2515 }
2516 }
2518 void JavaThread::remove_stack_guard_pages() {
2519 assert(Thread::current() == this, "from different thread");
2520 if (_stack_guard_state == stack_guard_unused) return;
2521 address low_addr = stack_base() - stack_size();
2522 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2524 if (os::allocate_stack_guard_pages()) {
2525 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2526 _stack_guard_state = stack_guard_unused;
2527 } else {
2528 warning("Attempt to deallocate stack guard pages failed.");
2529 }
2530 } else {
2531 if (_stack_guard_state == stack_guard_unused) return;
2532 if (os::unguard_memory((char *) low_addr, len)) {
2533 _stack_guard_state = stack_guard_unused;
2534 } else {
2535 warning("Attempt to unprotect stack guard pages failed.");
2536 }
2537 }
2538 }
2540 void JavaThread::enable_stack_yellow_zone() {
2541 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2542 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2544 // The base notation is from the stacks point of view, growing downward.
2545 // We need to adjust it to work correctly with guard_memory()
2546 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2548 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2549 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2551 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2552 _stack_guard_state = stack_guard_enabled;
2553 } else {
2554 warning("Attempt to guard stack yellow zone failed.");
2555 }
2556 enable_register_stack_guard();
2557 }
2559 void JavaThread::disable_stack_yellow_zone() {
2560 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2561 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2563 // Simply return if called for a thread that does not use guard pages.
2564 if (_stack_guard_state == stack_guard_unused) return;
2566 // The base notation is from the stacks point of view, growing downward.
2567 // We need to adjust it to work correctly with guard_memory()
2568 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2570 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2571 _stack_guard_state = stack_guard_yellow_disabled;
2572 } else {
2573 warning("Attempt to unguard stack yellow zone failed.");
2574 }
2575 disable_register_stack_guard();
2576 }
2578 void JavaThread::enable_stack_red_zone() {
2579 // The base notation is from the stacks point of view, growing downward.
2580 // We need to adjust it to work correctly with guard_memory()
2581 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2582 address base = stack_red_zone_base() - stack_red_zone_size();
2584 guarantee(base < stack_base(),"Error calculating stack red zone");
2585 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2587 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2588 warning("Attempt to guard stack red zone failed.");
2589 }
2590 }
2592 void JavaThread::disable_stack_red_zone() {
2593 // The base notation is from the stacks point of view, growing downward.
2594 // We need to adjust it to work correctly with guard_memory()
2595 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2596 address base = stack_red_zone_base() - stack_red_zone_size();
2597 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2598 warning("Attempt to unguard stack red zone failed.");
2599 }
2600 }
2602 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2603 // ignore is there is no stack
2604 if (!has_last_Java_frame()) return;
2605 // traverse the stack frames. Starts from top frame.
2606 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2607 frame* fr = fst.current();
2608 f(fr, fst.register_map());
2609 }
2610 }
2613 #ifndef PRODUCT
2614 // Deoptimization
2615 // Function for testing deoptimization
2616 void JavaThread::deoptimize() {
2617 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2618 StackFrameStream fst(this, UseBiasedLocking);
2619 bool deopt = false; // Dump stack only if a deopt actually happens.
2620 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2621 // Iterate over all frames in the thread and deoptimize
2622 for(; !fst.is_done(); fst.next()) {
2623 if(fst.current()->can_be_deoptimized()) {
2625 if (only_at) {
2626 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2627 // consists of comma or carriage return separated numbers so
2628 // search for the current bci in that string.
2629 address pc = fst.current()->pc();
2630 nmethod* nm = (nmethod*) fst.current()->cb();
2631 ScopeDesc* sd = nm->scope_desc_at( pc);
2632 char buffer[8];
2633 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2634 size_t len = strlen(buffer);
2635 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2636 while (found != NULL) {
2637 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2638 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2639 // Check that the bci found is bracketed by terminators.
2640 break;
2641 }
2642 found = strstr(found + 1, buffer);
2643 }
2644 if (!found) {
2645 continue;
2646 }
2647 }
2649 if (DebugDeoptimization && !deopt) {
2650 deopt = true; // One-time only print before deopt
2651 tty->print_cr("[BEFORE Deoptimization]");
2652 trace_frames();
2653 trace_stack();
2654 }
2655 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2656 }
2657 }
2659 if (DebugDeoptimization && deopt) {
2660 tty->print_cr("[AFTER Deoptimization]");
2661 trace_frames();
2662 }
2663 }
2666 // Make zombies
2667 void JavaThread::make_zombies() {
2668 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2669 if (fst.current()->can_be_deoptimized()) {
2670 // it is a Java nmethod
2671 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2672 nm->make_not_entrant();
2673 }
2674 }
2675 }
2676 #endif // PRODUCT
2679 void JavaThread::deoptimized_wrt_marked_nmethods() {
2680 if (!has_last_Java_frame()) return;
2681 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2682 StackFrameStream fst(this, UseBiasedLocking);
2683 for(; !fst.is_done(); fst.next()) {
2684 if (fst.current()->should_be_deoptimized()) {
2685 if (LogCompilation && xtty != NULL) {
2686 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2687 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2688 this->name(), nm != NULL ? nm->compile_id() : -1);
2689 }
2691 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2692 }
2693 }
2694 }
2697 // GC support
2698 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2700 void JavaThread::gc_epilogue() {
2701 frames_do(frame_gc_epilogue);
2702 }
2705 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2707 void JavaThread::gc_prologue() {
2708 frames_do(frame_gc_prologue);
2709 }
2711 // If the caller is a NamedThread, then remember, in the current scope,
2712 // the given JavaThread in its _processed_thread field.
2713 class RememberProcessedThread: public StackObj {
2714 NamedThread* _cur_thr;
2715 public:
2716 RememberProcessedThread(JavaThread* jthr) {
2717 Thread* thread = Thread::current();
2718 if (thread->is_Named_thread()) {
2719 _cur_thr = (NamedThread *)thread;
2720 _cur_thr->set_processed_thread(jthr);
2721 } else {
2722 _cur_thr = NULL;
2723 }
2724 }
2726 ~RememberProcessedThread() {
2727 if (_cur_thr) {
2728 _cur_thr->set_processed_thread(NULL);
2729 }
2730 }
2731 };
2733 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2734 // Verify that the deferred card marks have been flushed.
2735 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2737 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2738 // since there may be more than one thread using each ThreadProfiler.
2740 // Traverse the GCHandles
2741 Thread::oops_do(f, cld_f, cf);
2743 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2744 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2746 if (has_last_Java_frame()) {
2747 // Record JavaThread to GC thread
2748 RememberProcessedThread rpt(this);
2750 // Traverse the privileged stack
2751 if (_privileged_stack_top != NULL) {
2752 _privileged_stack_top->oops_do(f);
2753 }
2755 // traverse the registered growable array
2756 if (_array_for_gc != NULL) {
2757 for (int index = 0; index < _array_for_gc->length(); index++) {
2758 f->do_oop(_array_for_gc->adr_at(index));
2759 }
2760 }
2762 // Traverse the monitor chunks
2763 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2764 chunk->oops_do(f);
2765 }
2767 // Traverse the execution stack
2768 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2769 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2770 }
2771 }
2773 // callee_target is never live across a gc point so NULL it here should
2774 // it still contain a methdOop.
2776 set_callee_target(NULL);
2778 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2779 // If we have deferred set_locals there might be oops waiting to be
2780 // written
2781 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2782 if (list != NULL) {
2783 for (int i = 0; i < list->length(); i++) {
2784 list->at(i)->oops_do(f);
2785 }
2786 }
2788 // Traverse instance variables at the end since the GC may be moving things
2789 // around using this function
2790 f->do_oop((oop*) &_threadObj);
2791 f->do_oop((oop*) &_vm_result);
2792 f->do_oop((oop*) &_exception_oop);
2793 f->do_oop((oop*) &_pending_async_exception);
2795 if (jvmti_thread_state() != NULL) {
2796 jvmti_thread_state()->oops_do(f);
2797 }
2798 }
2800 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2801 Thread::nmethods_do(cf); // (super method is a no-op)
2803 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2804 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2806 if (has_last_Java_frame()) {
2807 // Traverse the execution stack
2808 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2809 fst.current()->nmethods_do(cf);
2810 }
2811 }
2812 }
2814 void JavaThread::metadata_do(void f(Metadata*)) {
2815 Thread::metadata_do(f);
2816 if (has_last_Java_frame()) {
2817 // Traverse the execution stack to call f() on the methods in the stack
2818 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2819 fst.current()->metadata_do(f);
2820 }
2821 } else if (is_Compiler_thread()) {
2822 // need to walk ciMetadata in current compile tasks to keep alive.
2823 CompilerThread* ct = (CompilerThread*)this;
2824 if (ct->env() != NULL) {
2825 ct->env()->metadata_do(f);
2826 }
2827 }
2828 }
2830 // Printing
2831 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2832 switch (_thread_state) {
2833 case _thread_uninitialized: return "_thread_uninitialized";
2834 case _thread_new: return "_thread_new";
2835 case _thread_new_trans: return "_thread_new_trans";
2836 case _thread_in_native: return "_thread_in_native";
2837 case _thread_in_native_trans: return "_thread_in_native_trans";
2838 case _thread_in_vm: return "_thread_in_vm";
2839 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2840 case _thread_in_Java: return "_thread_in_Java";
2841 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2842 case _thread_blocked: return "_thread_blocked";
2843 case _thread_blocked_trans: return "_thread_blocked_trans";
2844 default: return "unknown thread state";
2845 }
2846 }
2848 #ifndef PRODUCT
2849 void JavaThread::print_thread_state_on(outputStream *st) const {
2850 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2851 };
2852 void JavaThread::print_thread_state() const {
2853 print_thread_state_on(tty);
2854 };
2855 #endif // PRODUCT
2857 // Called by Threads::print() for VM_PrintThreads operation
2858 void JavaThread::print_on(outputStream *st) const {
2859 st->print("\"%s\" ", get_thread_name());
2860 oop thread_oop = threadObj();
2861 if (thread_oop != NULL) {
2862 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2863 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2864 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2865 }
2866 Thread::print_on(st);
2867 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2868 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2869 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2870 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2871 }
2872 #ifndef PRODUCT
2873 print_thread_state_on(st);
2874 _safepoint_state->print_on(st);
2875 #endif // PRODUCT
2876 }
2878 // Called by fatal error handler. The difference between this and
2879 // JavaThread::print() is that we can't grab lock or allocate memory.
2880 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2881 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2882 oop thread_obj = threadObj();
2883 if (thread_obj != NULL) {
2884 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2885 }
2886 st->print(" [");
2887 st->print("%s", _get_thread_state_name(_thread_state));
2888 if (osthread()) {
2889 st->print(", id=%d", osthread()->thread_id());
2890 }
2891 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2892 _stack_base - _stack_size, _stack_base);
2893 st->print("]");
2894 return;
2895 }
2897 // Verification
2899 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2901 void JavaThread::verify() {
2902 // Verify oops in the thread.
2903 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2905 // Verify the stack frames.
2906 frames_do(frame_verify);
2907 }
2909 // CR 6300358 (sub-CR 2137150)
2910 // Most callers of this method assume that it can't return NULL but a
2911 // thread may not have a name whilst it is in the process of attaching to
2912 // the VM - see CR 6412693, and there are places where a JavaThread can be
2913 // seen prior to having it's threadObj set (eg JNI attaching threads and
2914 // if vm exit occurs during initialization). These cases can all be accounted
2915 // for such that this method never returns NULL.
2916 const char* JavaThread::get_thread_name() const {
2917 #ifdef ASSERT
2918 // early safepoints can hit while current thread does not yet have TLS
2919 if (!SafepointSynchronize::is_at_safepoint()) {
2920 Thread *cur = Thread::current();
2921 if (!(cur->is_Java_thread() && cur == this)) {
2922 // Current JavaThreads are allowed to get their own name without
2923 // the Threads_lock.
2924 assert_locked_or_safepoint(Threads_lock);
2925 }
2926 }
2927 #endif // ASSERT
2928 return get_thread_name_string();
2929 }
2931 // Returns a non-NULL representation of this thread's name, or a suitable
2932 // descriptive string if there is no set name
2933 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2934 const char* name_str;
2935 oop thread_obj = threadObj();
2936 if (thread_obj != NULL) {
2937 typeArrayOop name = java_lang_Thread::name(thread_obj);
2938 if (name != NULL) {
2939 if (buf == NULL) {
2940 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2941 }
2942 else {
2943 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2944 }
2945 }
2946 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2947 name_str = "<no-name - thread is attaching>";
2948 }
2949 else {
2950 name_str = Thread::name();
2951 }
2952 }
2953 else {
2954 name_str = Thread::name();
2955 }
2956 assert(name_str != NULL, "unexpected NULL thread name");
2957 return name_str;
2958 }
2961 const char* JavaThread::get_threadgroup_name() const {
2962 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2963 oop thread_obj = threadObj();
2964 if (thread_obj != NULL) {
2965 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2966 if (thread_group != NULL) {
2967 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2968 // ThreadGroup.name can be null
2969 if (name != NULL) {
2970 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2971 return str;
2972 }
2973 }
2974 }
2975 return NULL;
2976 }
2978 const char* JavaThread::get_parent_name() const {
2979 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2980 oop thread_obj = threadObj();
2981 if (thread_obj != NULL) {
2982 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2983 if (thread_group != NULL) {
2984 oop parent = java_lang_ThreadGroup::parent(thread_group);
2985 if (parent != NULL) {
2986 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2987 // ThreadGroup.name can be null
2988 if (name != NULL) {
2989 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2990 return str;
2991 }
2992 }
2993 }
2994 }
2995 return NULL;
2996 }
2998 ThreadPriority JavaThread::java_priority() const {
2999 oop thr_oop = threadObj();
3000 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3001 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3002 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3003 return priority;
3004 }
3006 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3008 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3009 // Link Java Thread object <-> C++ Thread
3011 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3012 // and put it into a new Handle. The Handle "thread_oop" can then
3013 // be used to pass the C++ thread object to other methods.
3015 // Set the Java level thread object (jthread) field of the
3016 // new thread (a JavaThread *) to C++ thread object using the
3017 // "thread_oop" handle.
3019 // Set the thread field (a JavaThread *) of the
3020 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3022 Handle thread_oop(Thread::current(),
3023 JNIHandles::resolve_non_null(jni_thread));
3024 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3025 "must be initialized");
3026 set_threadObj(thread_oop());
3027 java_lang_Thread::set_thread(thread_oop(), this);
3029 if (prio == NoPriority) {
3030 prio = java_lang_Thread::priority(thread_oop());
3031 assert(prio != NoPriority, "A valid priority should be present");
3032 }
3034 // Push the Java priority down to the native thread; needs Threads_lock
3035 Thread::set_priority(this, prio);
3037 // Add the new thread to the Threads list and set it in motion.
3038 // We must have threads lock in order to call Threads::add.
3039 // It is crucial that we do not block before the thread is
3040 // added to the Threads list for if a GC happens, then the java_thread oop
3041 // will not be visited by GC.
3042 Threads::add(this);
3043 }
3045 oop JavaThread::current_park_blocker() {
3046 // Support for JSR-166 locks
3047 oop thread_oop = threadObj();
3048 if (thread_oop != NULL &&
3049 JDK_Version::current().supports_thread_park_blocker()) {
3050 return java_lang_Thread::park_blocker(thread_oop);
3051 }
3052 return NULL;
3053 }
3056 void JavaThread::print_stack_on(outputStream* st) {
3057 if (!has_last_Java_frame()) return;
3058 ResourceMark rm;
3059 HandleMark hm;
3061 RegisterMap reg_map(this);
3062 vframe* start_vf = last_java_vframe(®_map);
3063 int count = 0;
3064 for (vframe* f = start_vf; f; f = f->sender() ) {
3065 if (f->is_java_frame()) {
3066 javaVFrame* jvf = javaVFrame::cast(f);
3067 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3069 // Print out lock information
3070 if (JavaMonitorsInStackTrace) {
3071 jvf->print_lock_info_on(st, count);
3072 }
3073 } else {
3074 // Ignore non-Java frames
3075 }
3077 // Bail-out case for too deep stacks
3078 count++;
3079 if (MaxJavaStackTraceDepth == count) return;
3080 }
3081 }
3084 // JVMTI PopFrame support
3085 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3086 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3087 if (in_bytes(size_in_bytes) != 0) {
3088 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3089 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3090 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3091 }
3092 }
3094 void* JavaThread::popframe_preserved_args() {
3095 return _popframe_preserved_args;
3096 }
3098 ByteSize JavaThread::popframe_preserved_args_size() {
3099 return in_ByteSize(_popframe_preserved_args_size);
3100 }
3102 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3103 int sz = in_bytes(popframe_preserved_args_size());
3104 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3105 return in_WordSize(sz / wordSize);
3106 }
3108 void JavaThread::popframe_free_preserved_args() {
3109 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3110 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3111 _popframe_preserved_args = NULL;
3112 _popframe_preserved_args_size = 0;
3113 }
3115 #ifndef PRODUCT
3117 void JavaThread::trace_frames() {
3118 tty->print_cr("[Describe stack]");
3119 int frame_no = 1;
3120 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3121 tty->print(" %d. ", frame_no++);
3122 fst.current()->print_value_on(tty,this);
3123 tty->cr();
3124 }
3125 }
3127 class PrintAndVerifyOopClosure: public OopClosure {
3128 protected:
3129 template <class T> inline void do_oop_work(T* p) {
3130 oop obj = oopDesc::load_decode_heap_oop(p);
3131 if (obj == NULL) return;
3132 tty->print(INTPTR_FORMAT ": ", p);
3133 if (obj->is_oop_or_null()) {
3134 if (obj->is_objArray()) {
3135 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3136 } else {
3137 obj->print();
3138 }
3139 } else {
3140 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3141 }
3142 tty->cr();
3143 }
3144 public:
3145 virtual void do_oop(oop* p) { do_oop_work(p); }
3146 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3147 };
3150 static void oops_print(frame* f, const RegisterMap *map) {
3151 PrintAndVerifyOopClosure print;
3152 f->print_value();
3153 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3154 }
3156 // Print our all the locations that contain oops and whether they are
3157 // valid or not. This useful when trying to find the oldest frame
3158 // where an oop has gone bad since the frame walk is from youngest to
3159 // oldest.
3160 void JavaThread::trace_oops() {
3161 tty->print_cr("[Trace oops]");
3162 frames_do(oops_print);
3163 }
3166 #ifdef ASSERT
3167 // Print or validate the layout of stack frames
3168 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3169 ResourceMark rm;
3170 PRESERVE_EXCEPTION_MARK;
3171 FrameValues values;
3172 int frame_no = 0;
3173 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3174 fst.current()->describe(values, ++frame_no);
3175 if (depth == frame_no) break;
3176 }
3177 if (validate_only) {
3178 values.validate();
3179 } else {
3180 tty->print_cr("[Describe stack layout]");
3181 values.print(this);
3182 }
3183 }
3184 #endif
3186 void JavaThread::trace_stack_from(vframe* start_vf) {
3187 ResourceMark rm;
3188 int vframe_no = 1;
3189 for (vframe* f = start_vf; f; f = f->sender() ) {
3190 if (f->is_java_frame()) {
3191 javaVFrame::cast(f)->print_activation(vframe_no++);
3192 } else {
3193 f->print();
3194 }
3195 if (vframe_no > StackPrintLimit) {
3196 tty->print_cr("...<more frames>...");
3197 return;
3198 }
3199 }
3200 }
3203 void JavaThread::trace_stack() {
3204 if (!has_last_Java_frame()) return;
3205 ResourceMark rm;
3206 HandleMark hm;
3207 RegisterMap reg_map(this);
3208 trace_stack_from(last_java_vframe(®_map));
3209 }
3212 #endif // PRODUCT
3215 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3216 assert(reg_map != NULL, "a map must be given");
3217 frame f = last_frame();
3218 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3219 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3220 }
3221 return NULL;
3222 }
3225 Klass* JavaThread::security_get_caller_class(int depth) {
3226 vframeStream vfst(this);
3227 vfst.security_get_caller_frame(depth);
3228 if (!vfst.at_end()) {
3229 return vfst.method()->method_holder();
3230 }
3231 return NULL;
3232 }
3234 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3235 assert(thread->is_Compiler_thread(), "must be compiler thread");
3236 CompileBroker::compiler_thread_loop();
3237 }
3239 // Create a CompilerThread
3240 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3241 : JavaThread(&compiler_thread_entry) {
3242 _env = NULL;
3243 _log = NULL;
3244 _task = NULL;
3245 _queue = queue;
3246 _counters = counters;
3247 _buffer_blob = NULL;
3248 _scanned_nmethod = NULL;
3249 _compiler = NULL;
3251 #ifndef PRODUCT
3252 _ideal_graph_printer = NULL;
3253 #endif
3254 }
3256 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3257 JavaThread::oops_do(f, cld_f, cf);
3258 if (_scanned_nmethod != NULL && cf != NULL) {
3259 // Safepoints can occur when the sweeper is scanning an nmethod so
3260 // process it here to make sure it isn't unloaded in the middle of
3261 // a scan.
3262 cf->do_code_blob(_scanned_nmethod);
3263 }
3264 }
3267 // ======= Threads ========
3269 // The Threads class links together all active threads, and provides
3270 // operations over all threads. It is protected by its own Mutex
3271 // lock, which is also used in other contexts to protect thread
3272 // operations from having the thread being operated on from exiting
3273 // and going away unexpectedly (e.g., safepoint synchronization)
3275 JavaThread* Threads::_thread_list = NULL;
3276 int Threads::_number_of_threads = 0;
3277 int Threads::_number_of_non_daemon_threads = 0;
3278 int Threads::_return_code = 0;
3279 size_t JavaThread::_stack_size_at_create = 0;
3280 #ifdef ASSERT
3281 bool Threads::_vm_complete = false;
3282 #endif
3284 // All JavaThreads
3285 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3287 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3288 void Threads::threads_do(ThreadClosure* tc) {
3289 assert_locked_or_safepoint(Threads_lock);
3290 // ALL_JAVA_THREADS iterates through all JavaThreads
3291 ALL_JAVA_THREADS(p) {
3292 tc->do_thread(p);
3293 }
3294 // Someday we could have a table or list of all non-JavaThreads.
3295 // For now, just manually iterate through them.
3296 tc->do_thread(VMThread::vm_thread());
3297 Universe::heap()->gc_threads_do(tc);
3298 WatcherThread *wt = WatcherThread::watcher_thread();
3299 // Strictly speaking, the following NULL check isn't sufficient to make sure
3300 // the data for WatcherThread is still valid upon being examined. However,
3301 // considering that WatchThread terminates when the VM is on the way to
3302 // exit at safepoint, the chance of the above is extremely small. The right
3303 // way to prevent termination of WatcherThread would be to acquire
3304 // Terminator_lock, but we can't do that without violating the lock rank
3305 // checking in some cases.
3306 if (wt != NULL)
3307 tc->do_thread(wt);
3309 // If CompilerThreads ever become non-JavaThreads, add them here
3310 }
3312 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3314 extern void JDK_Version_init();
3316 // Check version
3317 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3319 // Initialize the output stream module
3320 ostream_init();
3322 // Process java launcher properties.
3323 Arguments::process_sun_java_launcher_properties(args);
3325 // Initialize the os module before using TLS
3326 os::init();
3328 // Initialize system properties.
3329 Arguments::init_system_properties();
3331 // So that JDK version can be used as a discrimintor when parsing arguments
3332 JDK_Version_init();
3334 // Update/Initialize System properties after JDK version number is known
3335 Arguments::init_version_specific_system_properties();
3337 // Parse arguments
3338 jint parse_result = Arguments::parse(args);
3339 if (parse_result != JNI_OK) return parse_result;
3341 os::init_before_ergo();
3343 jint ergo_result = Arguments::apply_ergo();
3344 if (ergo_result != JNI_OK) return ergo_result;
3346 if (PauseAtStartup) {
3347 os::pause();
3348 }
3350 #ifndef USDT2
3351 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3352 #else /* USDT2 */
3353 HOTSPOT_VM_INIT_BEGIN();
3354 #endif /* USDT2 */
3356 // Record VM creation timing statistics
3357 TraceVmCreationTime create_vm_timer;
3358 create_vm_timer.start();
3360 // Timing (must come after argument parsing)
3361 TraceTime timer("Create VM", TraceStartupTime);
3363 // Initialize the os module after parsing the args
3364 jint os_init_2_result = os::init_2();
3365 if (os_init_2_result != JNI_OK) return os_init_2_result;
3367 jint adjust_after_os_result = Arguments::adjust_after_os();
3368 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3370 // intialize TLS
3371 ThreadLocalStorage::init();
3373 // Bootstrap native memory tracking, so it can start recording memory
3374 // activities before worker thread is started. This is the first phase
3375 // of bootstrapping, VM is currently running in single-thread mode.
3376 MemTracker::bootstrap_single_thread();
3378 // Initialize output stream logging
3379 ostream_init_log();
3381 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3382 // Must be before create_vm_init_agents()
3383 if (Arguments::init_libraries_at_startup()) {
3384 convert_vm_init_libraries_to_agents();
3385 }
3387 // Launch -agentlib/-agentpath and converted -Xrun agents
3388 if (Arguments::init_agents_at_startup()) {
3389 create_vm_init_agents();
3390 }
3392 // Initialize Threads state
3393 _thread_list = NULL;
3394 _number_of_threads = 0;
3395 _number_of_non_daemon_threads = 0;
3397 // Initialize global data structures and create system classes in heap
3398 vm_init_globals();
3400 // Attach the main thread to this os thread
3401 JavaThread* main_thread = new JavaThread();
3402 main_thread->set_thread_state(_thread_in_vm);
3403 // must do this before set_active_handles and initialize_thread_local_storage
3404 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3405 // change the stack size recorded here to one based on the java thread
3406 // stacksize. This adjusted size is what is used to figure the placement
3407 // of the guard pages.
3408 main_thread->record_stack_base_and_size();
3409 main_thread->initialize_thread_local_storage();
3411 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3413 if (!main_thread->set_as_starting_thread()) {
3414 vm_shutdown_during_initialization(
3415 "Failed necessary internal allocation. Out of swap space");
3416 delete main_thread;
3417 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3418 return JNI_ENOMEM;
3419 }
3421 // Enable guard page *after* os::create_main_thread(), otherwise it would
3422 // crash Linux VM, see notes in os_linux.cpp.
3423 main_thread->create_stack_guard_pages();
3425 // Initialize Java-Level synchronization subsystem
3426 ObjectMonitor::Initialize() ;
3428 // Second phase of bootstrapping, VM is about entering multi-thread mode
3429 MemTracker::bootstrap_multi_thread();
3431 // Initialize global modules
3432 jint status = init_globals();
3433 if (status != JNI_OK) {
3434 delete main_thread;
3435 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3436 return status;
3437 }
3439 // Should be done after the heap is fully created
3440 main_thread->cache_global_variables();
3442 HandleMark hm;
3444 { MutexLocker mu(Threads_lock);
3445 Threads::add(main_thread);
3446 }
3448 // Any JVMTI raw monitors entered in onload will transition into
3449 // real raw monitor. VM is setup enough here for raw monitor enter.
3450 JvmtiExport::transition_pending_onload_raw_monitors();
3452 // Fully start NMT
3453 MemTracker::start();
3455 // Create the VMThread
3456 { TraceTime timer("Start VMThread", TraceStartupTime);
3457 VMThread::create();
3458 Thread* vmthread = VMThread::vm_thread();
3460 if (!os::create_thread(vmthread, os::vm_thread))
3461 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3463 // Wait for the VM thread to become ready, and VMThread::run to initialize
3464 // Monitors can have spurious returns, must always check another state flag
3465 {
3466 MutexLocker ml(Notify_lock);
3467 os::start_thread(vmthread);
3468 while (vmthread->active_handles() == NULL) {
3469 Notify_lock->wait();
3470 }
3471 }
3472 }
3474 assert (Universe::is_fully_initialized(), "not initialized");
3475 if (VerifyDuringStartup) {
3476 // Make sure we're starting with a clean slate.
3477 VM_Verify verify_op;
3478 VMThread::execute(&verify_op);
3479 }
3481 EXCEPTION_MARK;
3483 // At this point, the Universe is initialized, but we have not executed
3484 // any byte code. Now is a good time (the only time) to dump out the
3485 // internal state of the JVM for sharing.
3486 if (DumpSharedSpaces) {
3487 MetaspaceShared::preload_and_dump(CHECK_0);
3488 ShouldNotReachHere();
3489 }
3491 // Always call even when there are not JVMTI environments yet, since environments
3492 // may be attached late and JVMTI must track phases of VM execution
3493 JvmtiExport::enter_start_phase();
3495 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3496 JvmtiExport::post_vm_start();
3498 {
3499 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3501 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3502 create_vm_init_libraries();
3503 }
3505 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3507 // Initialize java_lang.System (needed before creating the thread)
3508 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3509 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3510 Handle thread_group = create_initial_thread_group(CHECK_0);
3511 Universe::set_main_thread_group(thread_group());
3512 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3513 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3514 main_thread->set_threadObj(thread_object);
3515 // Set thread status to running since main thread has
3516 // been started and running.
3517 java_lang_Thread::set_thread_status(thread_object,
3518 java_lang_Thread::RUNNABLE);
3520 // The VM creates & returns objects of this class. Make sure it's initialized.
3521 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3523 // The VM preresolves methods to these classes. Make sure that they get initialized
3524 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3525 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3526 call_initializeSystemClass(CHECK_0);
3528 // get the Java runtime name after java.lang.System is initialized
3529 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3530 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3532 // an instance of OutOfMemory exception has been allocated earlier
3533 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3534 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3535 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3536 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3537 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3538 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3539 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3540 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3541 }
3543 // See : bugid 4211085.
3544 // Background : the static initializer of java.lang.Compiler tries to read
3545 // property"java.compiler" and read & write property "java.vm.info".
3546 // When a security manager is installed through the command line
3547 // option "-Djava.security.manager", the above properties are not
3548 // readable and the static initializer for java.lang.Compiler fails
3549 // resulting in a NoClassDefFoundError. This can happen in any
3550 // user code which calls methods in java.lang.Compiler.
3551 // Hack : the hack is to pre-load and initialize this class, so that only
3552 // system domains are on the stack when the properties are read.
3553 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3554 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3555 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3556 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3557 // Once that is done, we should remove this hack.
3558 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3560 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3561 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3562 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3563 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3564 // This should also be taken out as soon as 4211383 gets fixed.
3565 reset_vm_info_property(CHECK_0);
3567 quicken_jni_functions();
3569 // Must be run after init_ft which initializes ft_enabled
3570 if (TRACE_INITIALIZE() != JNI_OK) {
3571 vm_exit_during_initialization("Failed to initialize tracing backend");
3572 }
3574 // Set flag that basic initialization has completed. Used by exceptions and various
3575 // debug stuff, that does not work until all basic classes have been initialized.
3576 set_init_completed();
3578 Metaspace::post_initialize();
3580 #ifndef USDT2
3581 HS_DTRACE_PROBE(hotspot, vm__init__end);
3582 #else /* USDT2 */
3583 HOTSPOT_VM_INIT_END();
3584 #endif /* USDT2 */
3586 // record VM initialization completion time
3587 #if INCLUDE_MANAGEMENT
3588 Management::record_vm_init_completed();
3589 #endif // INCLUDE_MANAGEMENT
3591 // Compute system loader. Note that this has to occur after set_init_completed, since
3592 // valid exceptions may be thrown in the process.
3593 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3594 // set_init_completed has just been called, causing exceptions not to be shortcut
3595 // anymore. We call vm_exit_during_initialization directly instead.
3596 SystemDictionary::compute_java_system_loader(THREAD);
3597 if (HAS_PENDING_EXCEPTION) {
3598 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3599 }
3601 #if INCLUDE_ALL_GCS
3602 // Support for ConcurrentMarkSweep. This should be cleaned up
3603 // and better encapsulated. The ugly nested if test would go away
3604 // once things are properly refactored. XXX YSR
3605 if (UseConcMarkSweepGC || UseG1GC) {
3606 if (UseConcMarkSweepGC) {
3607 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3608 } else {
3609 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3610 }
3611 if (HAS_PENDING_EXCEPTION) {
3612 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3613 }
3614 }
3615 #endif // INCLUDE_ALL_GCS
3617 // Always call even when there are not JVMTI environments yet, since environments
3618 // may be attached late and JVMTI must track phases of VM execution
3619 JvmtiExport::enter_live_phase();
3621 // Signal Dispatcher needs to be started before VMInit event is posted
3622 os::signal_init();
3624 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3625 if (!DisableAttachMechanism) {
3626 AttachListener::vm_start();
3627 if (StartAttachListener || AttachListener::init_at_startup()) {
3628 AttachListener::init();
3629 }
3630 }
3632 // Launch -Xrun agents
3633 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3634 // back-end can launch with -Xdebug -Xrunjdwp.
3635 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3636 create_vm_init_libraries();
3637 }
3639 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3640 JvmtiExport::post_vm_initialized();
3642 if (TRACE_START() != JNI_OK) {
3643 vm_exit_during_initialization("Failed to start tracing backend.");
3644 }
3646 if (CleanChunkPoolAsync) {
3647 Chunk::start_chunk_pool_cleaner_task();
3648 }
3650 // initialize compiler(s)
3651 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3652 CompileBroker::compilation_init();
3653 #endif
3655 if (EnableInvokeDynamic) {
3656 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3657 // It is done after compilers are initialized, because otherwise compilations of
3658 // signature polymorphic MH intrinsics can be missed
3659 // (see SystemDictionary::find_method_handle_intrinsic).
3660 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3661 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3662 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3663 }
3665 #if INCLUDE_MANAGEMENT
3666 Management::initialize(THREAD);
3667 #endif // INCLUDE_MANAGEMENT
3669 if (HAS_PENDING_EXCEPTION) {
3670 // management agent fails to start possibly due to
3671 // configuration problem and is responsible for printing
3672 // stack trace if appropriate. Simply exit VM.
3673 vm_exit(1);
3674 }
3676 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3677 if (MemProfiling) MemProfiler::engage();
3678 StatSampler::engage();
3679 if (CheckJNICalls) JniPeriodicChecker::engage();
3681 BiasedLocking::init();
3683 #if INCLUDE_RTM_OPT
3684 RTMLockingCounters::init();
3685 #endif
3687 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3688 call_postVMInitHook(THREAD);
3689 // The Java side of PostVMInitHook.run must deal with all
3690 // exceptions and provide means of diagnosis.
3691 if (HAS_PENDING_EXCEPTION) {
3692 CLEAR_PENDING_EXCEPTION;
3693 }
3694 }
3696 {
3697 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3698 // Make sure the watcher thread can be started by WatcherThread::start()
3699 // or by dynamic enrollment.
3700 WatcherThread::make_startable();
3701 // Start up the WatcherThread if there are any periodic tasks
3702 // NOTE: All PeriodicTasks should be registered by now. If they
3703 // aren't, late joiners might appear to start slowly (we might
3704 // take a while to process their first tick).
3705 if (PeriodicTask::num_tasks() > 0) {
3706 WatcherThread::start();
3707 }
3708 }
3710 // Give os specific code one last chance to start
3711 os::init_3();
3713 create_vm_timer.end();
3714 #ifdef ASSERT
3715 _vm_complete = true;
3716 #endif
3717 return JNI_OK;
3718 }
3720 // type for the Agent_OnLoad and JVM_OnLoad entry points
3721 extern "C" {
3722 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3723 }
3724 // Find a command line agent library and return its entry point for
3725 // -agentlib: -agentpath: -Xrun
3726 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3727 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3728 OnLoadEntry_t on_load_entry = NULL;
3729 void *library = NULL;
3731 if (!agent->valid()) {
3732 char buffer[JVM_MAXPATHLEN];
3733 char ebuf[1024];
3734 const char *name = agent->name();
3735 const char *msg = "Could not find agent library ";
3737 // First check to see if agent is statically linked into executable
3738 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3739 library = agent->os_lib();
3740 } else if (agent->is_absolute_path()) {
3741 library = os::dll_load(name, ebuf, sizeof ebuf);
3742 if (library == NULL) {
3743 const char *sub_msg = " in absolute path, with error: ";
3744 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3745 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3746 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3747 // If we can't find the agent, exit.
3748 vm_exit_during_initialization(buf, NULL);
3749 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3750 }
3751 } else {
3752 // Try to load the agent from the standard dll directory
3753 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3754 name)) {
3755 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3756 }
3757 if (library == NULL) { // Try the local directory
3758 char ns[1] = {0};
3759 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3760 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3761 }
3762 if (library == NULL) {
3763 const char *sub_msg = " on the library path, with error: ";
3764 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3765 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3766 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3767 // If we can't find the agent, exit.
3768 vm_exit_during_initialization(buf, NULL);
3769 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3770 }
3771 }
3772 }
3773 agent->set_os_lib(library);
3774 agent->set_valid();
3775 }
3777 // Find the OnLoad function.
3778 on_load_entry =
3779 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3780 false,
3781 on_load_symbols,
3782 num_symbol_entries));
3783 return on_load_entry;
3784 }
3786 // Find the JVM_OnLoad entry point
3787 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3788 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3789 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3790 }
3792 // Find the Agent_OnLoad entry point
3793 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3794 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3795 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3796 }
3798 // For backwards compatibility with -Xrun
3799 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3800 // treated like -agentpath:
3801 // Must be called before agent libraries are created
3802 void Threads::convert_vm_init_libraries_to_agents() {
3803 AgentLibrary* agent;
3804 AgentLibrary* next;
3806 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3807 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3808 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3810 // If there is an JVM_OnLoad function it will get called later,
3811 // otherwise see if there is an Agent_OnLoad
3812 if (on_load_entry == NULL) {
3813 on_load_entry = lookup_agent_on_load(agent);
3814 if (on_load_entry != NULL) {
3815 // switch it to the agent list -- so that Agent_OnLoad will be called,
3816 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3817 Arguments::convert_library_to_agent(agent);
3818 } else {
3819 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3820 }
3821 }
3822 }
3823 }
3825 // Create agents for -agentlib: -agentpath: and converted -Xrun
3826 // Invokes Agent_OnLoad
3827 // Called very early -- before JavaThreads exist
3828 void Threads::create_vm_init_agents() {
3829 extern struct JavaVM_ main_vm;
3830 AgentLibrary* agent;
3832 JvmtiExport::enter_onload_phase();
3834 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3835 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3837 if (on_load_entry != NULL) {
3838 // Invoke the Agent_OnLoad function
3839 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3840 if (err != JNI_OK) {
3841 vm_exit_during_initialization("agent library failed to init", agent->name());
3842 }
3843 } else {
3844 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3845 }
3846 }
3847 JvmtiExport::enter_primordial_phase();
3848 }
3850 extern "C" {
3851 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3852 }
3854 void Threads::shutdown_vm_agents() {
3855 // Send any Agent_OnUnload notifications
3856 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3857 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3858 extern struct JavaVM_ main_vm;
3859 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3861 // Find the Agent_OnUnload function.
3862 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3863 os::find_agent_function(agent,
3864 false,
3865 on_unload_symbols,
3866 num_symbol_entries));
3868 // Invoke the Agent_OnUnload function
3869 if (unload_entry != NULL) {
3870 JavaThread* thread = JavaThread::current();
3871 ThreadToNativeFromVM ttn(thread);
3872 HandleMark hm(thread);
3873 (*unload_entry)(&main_vm);
3874 }
3875 }
3876 }
3878 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3879 // Invokes JVM_OnLoad
3880 void Threads::create_vm_init_libraries() {
3881 extern struct JavaVM_ main_vm;
3882 AgentLibrary* agent;
3884 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3885 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3887 if (on_load_entry != NULL) {
3888 // Invoke the JVM_OnLoad function
3889 JavaThread* thread = JavaThread::current();
3890 ThreadToNativeFromVM ttn(thread);
3891 HandleMark hm(thread);
3892 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3893 if (err != JNI_OK) {
3894 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3895 }
3896 } else {
3897 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3898 }
3899 }
3900 }
3902 // Last thread running calls java.lang.Shutdown.shutdown()
3903 void JavaThread::invoke_shutdown_hooks() {
3904 HandleMark hm(this);
3906 // We could get here with a pending exception, if so clear it now.
3907 if (this->has_pending_exception()) {
3908 this->clear_pending_exception();
3909 }
3911 EXCEPTION_MARK;
3912 Klass* k =
3913 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3914 THREAD);
3915 if (k != NULL) {
3916 // SystemDictionary::resolve_or_null will return null if there was
3917 // an exception. If we cannot load the Shutdown class, just don't
3918 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3919 // and finalizers (if runFinalizersOnExit is set) won't be run.
3920 // Note that if a shutdown hook was registered or runFinalizersOnExit
3921 // was called, the Shutdown class would have already been loaded
3922 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3923 instanceKlassHandle shutdown_klass (THREAD, k);
3924 JavaValue result(T_VOID);
3925 JavaCalls::call_static(&result,
3926 shutdown_klass,
3927 vmSymbols::shutdown_method_name(),
3928 vmSymbols::void_method_signature(),
3929 THREAD);
3930 }
3931 CLEAR_PENDING_EXCEPTION;
3932 }
3934 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3935 // the program falls off the end of main(). Another VM exit path is through
3936 // vm_exit() when the program calls System.exit() to return a value or when
3937 // there is a serious error in VM. The two shutdown paths are not exactly
3938 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3939 // and VM_Exit op at VM level.
3940 //
3941 // Shutdown sequence:
3942 // + Shutdown native memory tracking if it is on
3943 // + Wait until we are the last non-daemon thread to execute
3944 // <-- every thing is still working at this moment -->
3945 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3946 // shutdown hooks, run finalizers if finalization-on-exit
3947 // + Call before_exit(), prepare for VM exit
3948 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3949 // currently the only user of this mechanism is File.deleteOnExit())
3950 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3951 // post thread end and vm death events to JVMTI,
3952 // stop signal thread
3953 // + Call JavaThread::exit(), it will:
3954 // > release JNI handle blocks, remove stack guard pages
3955 // > remove this thread from Threads list
3956 // <-- no more Java code from this thread after this point -->
3957 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3958 // the compiler threads at safepoint
3959 // <-- do not use anything that could get blocked by Safepoint -->
3960 // + Disable tracing at JNI/JVM barriers
3961 // + Set _vm_exited flag for threads that are still running native code
3962 // + Delete this thread
3963 // + Call exit_globals()
3964 // > deletes tty
3965 // > deletes PerfMemory resources
3966 // + Return to caller
3968 bool Threads::destroy_vm() {
3969 JavaThread* thread = JavaThread::current();
3971 #ifdef ASSERT
3972 _vm_complete = false;
3973 #endif
3974 // Wait until we are the last non-daemon thread to execute
3975 { MutexLocker nu(Threads_lock);
3976 while (Threads::number_of_non_daemon_threads() > 1 )
3977 // This wait should make safepoint checks, wait without a timeout,
3978 // and wait as a suspend-equivalent condition.
3979 //
3980 // Note: If the FlatProfiler is running and this thread is waiting
3981 // for another non-daemon thread to finish, then the FlatProfiler
3982 // is waiting for the external suspend request on this thread to
3983 // complete. wait_for_ext_suspend_completion() will eventually
3984 // timeout, but that takes time. Making this wait a suspend-
3985 // equivalent condition solves that timeout problem.
3986 //
3987 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3988 Mutex::_as_suspend_equivalent_flag);
3989 }
3991 // Hang forever on exit if we are reporting an error.
3992 if (ShowMessageBoxOnError && is_error_reported()) {
3993 os::infinite_sleep();
3994 }
3995 os::wait_for_keypress_at_exit();
3997 if (JDK_Version::is_jdk12x_version()) {
3998 // We are the last thread running, so check if finalizers should be run.
3999 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4000 HandleMark rm(thread);
4001 Universe::run_finalizers_on_exit();
4002 } else {
4003 // run Java level shutdown hooks
4004 thread->invoke_shutdown_hooks();
4005 }
4007 before_exit(thread);
4009 thread->exit(true);
4011 // Stop VM thread.
4012 {
4013 // 4945125 The vm thread comes to a safepoint during exit.
4014 // GC vm_operations can get caught at the safepoint, and the
4015 // heap is unparseable if they are caught. Grab the Heap_lock
4016 // to prevent this. The GC vm_operations will not be able to
4017 // queue until after the vm thread is dead. After this point,
4018 // we'll never emerge out of the safepoint before the VM exits.
4020 MutexLocker ml(Heap_lock);
4022 VMThread::wait_for_vm_thread_exit();
4023 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4024 VMThread::destroy();
4025 }
4027 // clean up ideal graph printers
4028 #if defined(COMPILER2) && !defined(PRODUCT)
4029 IdealGraphPrinter::clean_up();
4030 #endif
4032 // Now, all Java threads are gone except daemon threads. Daemon threads
4033 // running Java code or in VM are stopped by the Safepoint. However,
4034 // daemon threads executing native code are still running. But they
4035 // will be stopped at native=>Java/VM barriers. Note that we can't
4036 // simply kill or suspend them, as it is inherently deadlock-prone.
4038 #ifndef PRODUCT
4039 // disable function tracing at JNI/JVM barriers
4040 TraceJNICalls = false;
4041 TraceJVMCalls = false;
4042 TraceRuntimeCalls = false;
4043 #endif
4045 VM_Exit::set_vm_exited();
4047 notify_vm_shutdown();
4049 delete thread;
4051 // exit_globals() will delete tty
4052 exit_globals();
4054 return true;
4055 }
4058 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4059 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4060 return is_supported_jni_version(version);
4061 }
4064 jboolean Threads::is_supported_jni_version(jint version) {
4065 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4066 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4067 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4068 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4069 return JNI_FALSE;
4070 }
4073 void Threads::add(JavaThread* p, bool force_daemon) {
4074 // The threads lock must be owned at this point
4075 assert_locked_or_safepoint(Threads_lock);
4077 // See the comment for this method in thread.hpp for its purpose and
4078 // why it is called here.
4079 p->initialize_queues();
4080 p->set_next(_thread_list);
4081 _thread_list = p;
4082 _number_of_threads++;
4083 oop threadObj = p->threadObj();
4084 bool daemon = true;
4085 // Bootstrapping problem: threadObj can be null for initial
4086 // JavaThread (or for threads attached via JNI)
4087 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4088 _number_of_non_daemon_threads++;
4089 daemon = false;
4090 }
4092 p->set_safepoint_visible(true);
4094 ThreadService::add_thread(p, daemon);
4096 // Possible GC point.
4097 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4098 }
4100 void Threads::remove(JavaThread* p) {
4101 // Extra scope needed for Thread_lock, so we can check
4102 // that we do not remove thread without safepoint code notice
4103 { MutexLocker ml(Threads_lock);
4105 assert(includes(p), "p must be present");
4107 JavaThread* current = _thread_list;
4108 JavaThread* prev = NULL;
4110 while (current != p) {
4111 prev = current;
4112 current = current->next();
4113 }
4115 if (prev) {
4116 prev->set_next(current->next());
4117 } else {
4118 _thread_list = p->next();
4119 }
4120 _number_of_threads--;
4121 oop threadObj = p->threadObj();
4122 bool daemon = true;
4123 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4124 _number_of_non_daemon_threads--;
4125 daemon = false;
4127 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4128 // on destroy_vm will wake up.
4129 if (number_of_non_daemon_threads() == 1)
4130 Threads_lock->notify_all();
4131 }
4132 ThreadService::remove_thread(p, daemon);
4134 // Make sure that safepoint code disregard this thread. This is needed since
4135 // the thread might mess around with locks after this point. This can cause it
4136 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4137 // of this thread since it is removed from the queue.
4138 p->set_terminated_value();
4140 // Now, this thread is not visible to safepoint
4141 p->set_safepoint_visible(false);
4142 // once the thread becomes safepoint invisible, we can not use its per-thread
4143 // recorder. And Threads::do_threads() no longer walks this thread, so we have
4144 // to release its per-thread recorder here.
4145 MemTracker::thread_exiting(p);
4146 } // unlock Threads_lock
4148 // Since Events::log uses a lock, we grab it outside the Threads_lock
4149 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4150 }
4152 // Threads_lock must be held when this is called (or must be called during a safepoint)
4153 bool Threads::includes(JavaThread* p) {
4154 assert(Threads_lock->is_locked(), "sanity check");
4155 ALL_JAVA_THREADS(q) {
4156 if (q == p ) {
4157 return true;
4158 }
4159 }
4160 return false;
4161 }
4163 // Operations on the Threads list for GC. These are not explicitly locked,
4164 // but the garbage collector must provide a safe context for them to run.
4165 // In particular, these things should never be called when the Threads_lock
4166 // is held by some other thread. (Note: the Safepoint abstraction also
4167 // uses the Threads_lock to gurantee this property. It also makes sure that
4168 // all threads gets blocked when exiting or starting).
4170 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4171 ALL_JAVA_THREADS(p) {
4172 p->oops_do(f, cld_f, cf);
4173 }
4174 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4175 }
4177 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4178 // Introduce a mechanism allowing parallel threads to claim threads as
4179 // root groups. Overhead should be small enough to use all the time,
4180 // even in sequential code.
4181 SharedHeap* sh = SharedHeap::heap();
4182 // Cannot yet substitute active_workers for n_par_threads
4183 // because of G1CollectedHeap::verify() use of
4184 // SharedHeap::process_roots(). n_par_threads == 0 will
4185 // turn off parallelism in process_roots while active_workers
4186 // is being used for parallelism elsewhere.
4187 bool is_par = sh->n_par_threads() > 0;
4188 assert(!is_par ||
4189 (SharedHeap::heap()->n_par_threads() ==
4190 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4191 int cp = SharedHeap::heap()->strong_roots_parity();
4192 ALL_JAVA_THREADS(p) {
4193 if (p->claim_oops_do(is_par, cp)) {
4194 p->oops_do(f, cld_f, cf);
4195 }
4196 }
4197 VMThread* vmt = VMThread::vm_thread();
4198 if (vmt->claim_oops_do(is_par, cp)) {
4199 vmt->oops_do(f, cld_f, cf);
4200 }
4201 }
4203 #if INCLUDE_ALL_GCS
4204 // Used by ParallelScavenge
4205 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4206 ALL_JAVA_THREADS(p) {
4207 q->enqueue(new ThreadRootsTask(p));
4208 }
4209 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4210 }
4212 // Used by Parallel Old
4213 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4214 ALL_JAVA_THREADS(p) {
4215 q->enqueue(new ThreadRootsMarkingTask(p));
4216 }
4217 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4218 }
4219 #endif // INCLUDE_ALL_GCS
4221 void Threads::nmethods_do(CodeBlobClosure* cf) {
4222 ALL_JAVA_THREADS(p) {
4223 p->nmethods_do(cf);
4224 }
4225 VMThread::vm_thread()->nmethods_do(cf);
4226 }
4228 void Threads::metadata_do(void f(Metadata*)) {
4229 ALL_JAVA_THREADS(p) {
4230 p->metadata_do(f);
4231 }
4232 }
4234 void Threads::gc_epilogue() {
4235 ALL_JAVA_THREADS(p) {
4236 p->gc_epilogue();
4237 }
4238 }
4240 void Threads::gc_prologue() {
4241 ALL_JAVA_THREADS(p) {
4242 p->gc_prologue();
4243 }
4244 }
4246 void Threads::deoptimized_wrt_marked_nmethods() {
4247 ALL_JAVA_THREADS(p) {
4248 p->deoptimized_wrt_marked_nmethods();
4249 }
4250 }
4253 // Get count Java threads that are waiting to enter the specified monitor.
4254 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4255 address monitor, bool doLock) {
4256 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4257 "must grab Threads_lock or be at safepoint");
4258 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4260 int i = 0;
4261 {
4262 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4263 ALL_JAVA_THREADS(p) {
4264 if (p->is_Compiler_thread()) continue;
4266 address pending = (address)p->current_pending_monitor();
4267 if (pending == monitor) { // found a match
4268 if (i < count) result->append(p); // save the first count matches
4269 i++;
4270 }
4271 }
4272 }
4273 return result;
4274 }
4277 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4278 assert(doLock ||
4279 Threads_lock->owned_by_self() ||
4280 SafepointSynchronize::is_at_safepoint(),
4281 "must grab Threads_lock or be at safepoint");
4283 // NULL owner means not locked so we can skip the search
4284 if (owner == NULL) return NULL;
4286 {
4287 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4288 ALL_JAVA_THREADS(p) {
4289 // first, see if owner is the address of a Java thread
4290 if (owner == (address)p) return p;
4291 }
4292 }
4293 // Cannot assert on lack of success here since this function may be
4294 // used by code that is trying to report useful problem information
4295 // like deadlock detection.
4296 if (UseHeavyMonitors) return NULL;
4298 //
4299 // If we didn't find a matching Java thread and we didn't force use of
4300 // heavyweight monitors, then the owner is the stack address of the
4301 // Lock Word in the owning Java thread's stack.
4302 //
4303 JavaThread* the_owner = NULL;
4304 {
4305 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4306 ALL_JAVA_THREADS(q) {
4307 if (q->is_lock_owned(owner)) {
4308 the_owner = q;
4309 break;
4310 }
4311 }
4312 }
4313 // cannot assert on lack of success here; see above comment
4314 return the_owner;
4315 }
4317 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4318 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4319 char buf[32];
4320 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4322 st->print_cr("Full thread dump %s (%s %s):",
4323 Abstract_VM_Version::vm_name(),
4324 Abstract_VM_Version::vm_release(),
4325 Abstract_VM_Version::vm_info_string()
4326 );
4327 st->cr();
4329 #if INCLUDE_ALL_GCS
4330 // Dump concurrent locks
4331 ConcurrentLocksDump concurrent_locks;
4332 if (print_concurrent_locks) {
4333 concurrent_locks.dump_at_safepoint();
4334 }
4335 #endif // INCLUDE_ALL_GCS
4337 ALL_JAVA_THREADS(p) {
4338 ResourceMark rm;
4339 p->print_on(st);
4340 if (print_stacks) {
4341 if (internal_format) {
4342 p->trace_stack();
4343 } else {
4344 p->print_stack_on(st);
4345 }
4346 }
4347 st->cr();
4348 #if INCLUDE_ALL_GCS
4349 if (print_concurrent_locks) {
4350 concurrent_locks.print_locks_on(p, st);
4351 }
4352 #endif // INCLUDE_ALL_GCS
4353 }
4355 VMThread::vm_thread()->print_on(st);
4356 st->cr();
4357 Universe::heap()->print_gc_threads_on(st);
4358 WatcherThread* wt = WatcherThread::watcher_thread();
4359 if (wt != NULL) {
4360 wt->print_on(st);
4361 st->cr();
4362 }
4363 CompileBroker::print_compiler_threads_on(st);
4364 st->flush();
4365 }
4367 // Threads::print_on_error() is called by fatal error handler. It's possible
4368 // that VM is not at safepoint and/or current thread is inside signal handler.
4369 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4370 // memory (even in resource area), it might deadlock the error handler.
4371 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4372 bool found_current = false;
4373 st->print_cr("Java Threads: ( => current thread )");
4374 ALL_JAVA_THREADS(thread) {
4375 bool is_current = (current == thread);
4376 found_current = found_current || is_current;
4378 st->print("%s", is_current ? "=>" : " ");
4380 st->print(PTR_FORMAT, thread);
4381 st->print(" ");
4382 thread->print_on_error(st, buf, buflen);
4383 st->cr();
4384 }
4385 st->cr();
4387 st->print_cr("Other Threads:");
4388 if (VMThread::vm_thread()) {
4389 bool is_current = (current == VMThread::vm_thread());
4390 found_current = found_current || is_current;
4391 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4393 st->print(PTR_FORMAT, VMThread::vm_thread());
4394 st->print(" ");
4395 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4396 st->cr();
4397 }
4398 WatcherThread* wt = WatcherThread::watcher_thread();
4399 if (wt != NULL) {
4400 bool is_current = (current == wt);
4401 found_current = found_current || is_current;
4402 st->print("%s", is_current ? "=>" : " ");
4404 st->print(PTR_FORMAT, wt);
4405 st->print(" ");
4406 wt->print_on_error(st, buf, buflen);
4407 st->cr();
4408 }
4409 if (!found_current) {
4410 st->cr();
4411 st->print("=>" PTR_FORMAT " (exited) ", current);
4412 current->print_on_error(st, buf, buflen);
4413 st->cr();
4414 }
4415 }
4417 // Internal SpinLock and Mutex
4418 // Based on ParkEvent
4420 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4421 //
4422 // We employ SpinLocks _only for low-contention, fixed-length
4423 // short-duration critical sections where we're concerned
4424 // about native mutex_t or HotSpot Mutex:: latency.
4425 // The mux construct provides a spin-then-block mutual exclusion
4426 // mechanism.
4427 //
4428 // Testing has shown that contention on the ListLock guarding gFreeList
4429 // is common. If we implement ListLock as a simple SpinLock it's common
4430 // for the JVM to devolve to yielding with little progress. This is true
4431 // despite the fact that the critical sections protected by ListLock are
4432 // extremely short.
4433 //
4434 // TODO-FIXME: ListLock should be of type SpinLock.
4435 // We should make this a 1st-class type, integrated into the lock
4436 // hierarchy as leaf-locks. Critically, the SpinLock structure
4437 // should have sufficient padding to avoid false-sharing and excessive
4438 // cache-coherency traffic.
4441 typedef volatile int SpinLockT ;
4443 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4444 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4445 return ; // normal fast-path return
4446 }
4448 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4449 TEVENT (SpinAcquire - ctx) ;
4450 int ctr = 0 ;
4451 int Yields = 0 ;
4452 for (;;) {
4453 while (*adr != 0) {
4454 ++ctr ;
4455 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4456 if (Yields > 5) {
4457 os::naked_short_sleep(1);
4458 } else {
4459 os::NakedYield() ;
4460 ++Yields ;
4461 }
4462 } else {
4463 SpinPause() ;
4464 }
4465 }
4466 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4467 }
4468 }
4470 void Thread::SpinRelease (volatile int * adr) {
4471 assert (*adr != 0, "invariant") ;
4472 OrderAccess::fence() ; // guarantee at least release consistency.
4473 // Roach-motel semantics.
4474 // It's safe if subsequent LDs and STs float "up" into the critical section,
4475 // but prior LDs and STs within the critical section can't be allowed
4476 // to reorder or float past the ST that releases the lock.
4477 *adr = 0 ;
4478 }
4480 // muxAcquire and muxRelease:
4481 //
4482 // * muxAcquire and muxRelease support a single-word lock-word construct.
4483 // The LSB of the word is set IFF the lock is held.
4484 // The remainder of the word points to the head of a singly-linked list
4485 // of threads blocked on the lock.
4486 //
4487 // * The current implementation of muxAcquire-muxRelease uses its own
4488 // dedicated Thread._MuxEvent instance. If we're interested in
4489 // minimizing the peak number of extant ParkEvent instances then
4490 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4491 // as certain invariants were satisfied. Specifically, care would need
4492 // to be taken with regards to consuming unpark() "permits".
4493 // A safe rule of thumb is that a thread would never call muxAcquire()
4494 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4495 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4496 // consume an unpark() permit intended for monitorenter, for instance.
4497 // One way around this would be to widen the restricted-range semaphore
4498 // implemented in park(). Another alternative would be to provide
4499 // multiple instances of the PlatformEvent() for each thread. One
4500 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4501 //
4502 // * Usage:
4503 // -- Only as leaf locks
4504 // -- for short-term locking only as muxAcquire does not perform
4505 // thread state transitions.
4506 //
4507 // Alternatives:
4508 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4509 // but with parking or spin-then-park instead of pure spinning.
4510 // * Use Taura-Oyama-Yonenzawa locks.
4511 // * It's possible to construct a 1-0 lock if we encode the lockword as
4512 // (List,LockByte). Acquire will CAS the full lockword while Release
4513 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4514 // acquiring threads use timers (ParkTimed) to detect and recover from
4515 // the stranding window. Thread/Node structures must be aligned on 256-byte
4516 // boundaries by using placement-new.
4517 // * Augment MCS with advisory back-link fields maintained with CAS().
4518 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4519 // The validity of the backlinks must be ratified before we trust the value.
4520 // If the backlinks are invalid the exiting thread must back-track through the
4521 // the forward links, which are always trustworthy.
4522 // * Add a successor indication. The LockWord is currently encoded as
4523 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4524 // to provide the usual futile-wakeup optimization.
4525 // See RTStt for details.
4526 // * Consider schedctl.sc_nopreempt to cover the critical section.
4527 //
4530 typedef volatile intptr_t MutexT ; // Mux Lock-word
4531 enum MuxBits { LOCKBIT = 1 } ;
4533 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4534 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4535 if (w == 0) return ;
4536 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4537 return ;
4538 }
4540 TEVENT (muxAcquire - Contention) ;
4541 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4542 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4543 for (;;) {
4544 int its = (os::is_MP() ? 100 : 0) + 1 ;
4546 // Optional spin phase: spin-then-park strategy
4547 while (--its >= 0) {
4548 w = *Lock ;
4549 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4550 return ;
4551 }
4552 }
4554 Self->reset() ;
4555 Self->OnList = intptr_t(Lock) ;
4556 // The following fence() isn't _strictly necessary as the subsequent
4557 // CAS() both serializes execution and ratifies the fetched *Lock value.
4558 OrderAccess::fence();
4559 for (;;) {
4560 w = *Lock ;
4561 if ((w & LOCKBIT) == 0) {
4562 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4563 Self->OnList = 0 ; // hygiene - allows stronger asserts
4564 return ;
4565 }
4566 continue ; // Interference -- *Lock changed -- Just retry
4567 }
4568 assert (w & LOCKBIT, "invariant") ;
4569 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4570 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4571 }
4573 while (Self->OnList != 0) {
4574 Self->park() ;
4575 }
4576 }
4577 }
4579 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4580 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4581 if (w == 0) return ;
4582 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4583 return ;
4584 }
4586 TEVENT (muxAcquire - Contention) ;
4587 ParkEvent * ReleaseAfter = NULL ;
4588 if (ev == NULL) {
4589 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4590 }
4591 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4592 for (;;) {
4593 guarantee (ev->OnList == 0, "invariant") ;
4594 int its = (os::is_MP() ? 100 : 0) + 1 ;
4596 // Optional spin phase: spin-then-park strategy
4597 while (--its >= 0) {
4598 w = *Lock ;
4599 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4600 if (ReleaseAfter != NULL) {
4601 ParkEvent::Release (ReleaseAfter) ;
4602 }
4603 return ;
4604 }
4605 }
4607 ev->reset() ;
4608 ev->OnList = intptr_t(Lock) ;
4609 // The following fence() isn't _strictly necessary as the subsequent
4610 // CAS() both serializes execution and ratifies the fetched *Lock value.
4611 OrderAccess::fence();
4612 for (;;) {
4613 w = *Lock ;
4614 if ((w & LOCKBIT) == 0) {
4615 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4616 ev->OnList = 0 ;
4617 // We call ::Release while holding the outer lock, thus
4618 // artificially lengthening the critical section.
4619 // Consider deferring the ::Release() until the subsequent unlock(),
4620 // after we've dropped the outer lock.
4621 if (ReleaseAfter != NULL) {
4622 ParkEvent::Release (ReleaseAfter) ;
4623 }
4624 return ;
4625 }
4626 continue ; // Interference -- *Lock changed -- Just retry
4627 }
4628 assert (w & LOCKBIT, "invariant") ;
4629 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4630 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4631 }
4633 while (ev->OnList != 0) {
4634 ev->park() ;
4635 }
4636 }
4637 }
4639 // Release() must extract a successor from the list and then wake that thread.
4640 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4641 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4642 // Release() would :
4643 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4644 // (B) Extract a successor from the private list "in-hand"
4645 // (C) attempt to CAS() the residual back into *Lock over null.
4646 // If there were any newly arrived threads and the CAS() would fail.
4647 // In that case Release() would detach the RATs, re-merge the list in-hand
4648 // with the RATs and repeat as needed. Alternately, Release() might
4649 // detach and extract a successor, but then pass the residual list to the wakee.
4650 // The wakee would be responsible for reattaching and remerging before it
4651 // competed for the lock.
4652 //
4653 // Both "pop" and DMR are immune from ABA corruption -- there can be
4654 // multiple concurrent pushers, but only one popper or detacher.
4655 // This implementation pops from the head of the list. This is unfair,
4656 // but tends to provide excellent throughput as hot threads remain hot.
4657 // (We wake recently run threads first).
4659 void Thread::muxRelease (volatile intptr_t * Lock) {
4660 for (;;) {
4661 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4662 assert (w & LOCKBIT, "invariant") ;
4663 if (w == LOCKBIT) return ;
4664 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4665 assert (List != NULL, "invariant") ;
4666 assert (List->OnList == intptr_t(Lock), "invariant") ;
4667 ParkEvent * nxt = List->ListNext ;
4669 // The following CAS() releases the lock and pops the head element.
4670 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4671 continue ;
4672 }
4673 List->OnList = 0 ;
4674 OrderAccess::fence() ;
4675 List->unpark () ;
4676 return ;
4677 }
4678 }
4681 void Threads::verify() {
4682 ALL_JAVA_THREADS(p) {
4683 p->verify();
4684 }
4685 VMThread* thread = VMThread::vm_thread();
4686 if (thread != NULL) thread->verify();
4687 }