Wed, 16 Jan 2013 16:30:04 +0100
8006403: Regression: jstack failed due to the FieldInfo regression in SA
Reviewed-by: sla, dholmes
Contributed-by: Aleksey Shipilev <aleksey.shipilev@oracle.com>
1 /*
2 * Copyright (c) 1997, 2012, 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/aprofiler.hpp"
49 #include "runtime/arguments.hpp"
50 #include "runtime/biasedLocking.hpp"
51 #include "runtime/deoptimization.hpp"
52 #include "runtime/fprofiler.hpp"
53 #include "runtime/frame.inline.hpp"
54 #include "runtime/init.hpp"
55 #include "runtime/interfaceSupport.hpp"
56 #include "runtime/java.hpp"
57 #include "runtime/javaCalls.hpp"
58 #include "runtime/jniPeriodicChecker.hpp"
59 #include "runtime/memprofiler.hpp"
60 #include "runtime/mutexLocker.hpp"
61 #include "runtime/objectMonitor.hpp"
62 #include "runtime/osThread.hpp"
63 #include "runtime/safepoint.hpp"
64 #include "runtime/sharedRuntime.hpp"
65 #include "runtime/statSampler.hpp"
66 #include "runtime/stubRoutines.hpp"
67 #include "runtime/task.hpp"
68 #include "runtime/thread.inline.hpp"
69 #include "runtime/threadCritical.hpp"
70 #include "runtime/threadLocalStorage.hpp"
71 #include "runtime/vframe.hpp"
72 #include "runtime/vframeArray.hpp"
73 #include "runtime/vframe_hp.hpp"
74 #include "runtime/vmThread.hpp"
75 #include "runtime/vm_operations.hpp"
76 #include "services/attachListener.hpp"
77 #include "services/management.hpp"
78 #include "services/memTracker.hpp"
79 #include "services/threadService.hpp"
80 #include "trace/traceEventTypes.hpp"
81 #include "utilities/defaultStream.hpp"
82 #include "utilities/dtrace.hpp"
83 #include "utilities/events.hpp"
84 #include "utilities/preserveException.hpp"
85 #ifdef TARGET_OS_FAMILY_linux
86 # include "os_linux.inline.hpp"
87 #endif
88 #ifdef TARGET_OS_FAMILY_solaris
89 # include "os_solaris.inline.hpp"
90 #endif
91 #ifdef TARGET_OS_FAMILY_windows
92 # include "os_windows.inline.hpp"
93 #endif
94 #ifdef TARGET_OS_FAMILY_bsd
95 # include "os_bsd.inline.hpp"
96 #endif
97 #ifndef SERIALGC
98 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
99 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
100 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
101 #endif
102 #ifdef COMPILER1
103 #include "c1/c1_Compiler.hpp"
104 #endif
105 #ifdef COMPILER2
106 #include "opto/c2compiler.hpp"
107 #include "opto/idealGraphPrinter.hpp"
108 #endif
110 #ifdef DTRACE_ENABLED
112 // Only bother with this argument setup if dtrace is available
114 #ifndef USDT2
115 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
116 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
117 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
118 intptr_t, intptr_t, bool);
119 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
120 intptr_t, intptr_t, bool);
122 #define DTRACE_THREAD_PROBE(probe, javathread) \
123 { \
124 ResourceMark rm(this); \
125 int len = 0; \
126 const char* name = (javathread)->get_thread_name(); \
127 len = strlen(name); \
128 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
129 name, len, \
130 java_lang_Thread::thread_id((javathread)->threadObj()), \
131 (javathread)->osthread()->thread_id(), \
132 java_lang_Thread::is_daemon((javathread)->threadObj())); \
133 }
135 #else /* USDT2 */
137 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
138 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
140 #define DTRACE_THREAD_PROBE(probe, javathread) \
141 { \
142 ResourceMark rm(this); \
143 int len = 0; \
144 const char* name = (javathread)->get_thread_name(); \
145 len = strlen(name); \
146 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
147 (char *) name, len, \
148 java_lang_Thread::thread_id((javathread)->threadObj()), \
149 (uintptr_t) (javathread)->osthread()->thread_id(), \
150 java_lang_Thread::is_daemon((javathread)->threadObj())); \
151 }
153 #endif /* USDT2 */
155 #else // ndef DTRACE_ENABLED
157 #define DTRACE_THREAD_PROBE(probe, javathread)
159 #endif // ndef DTRACE_ENABLED
162 // Class hierarchy
163 // - Thread
164 // - VMThread
165 // - WatcherThread
166 // - ConcurrentMarkSweepThread
167 // - JavaThread
168 // - CompilerThread
170 // ======= Thread ========
171 // Support for forcing alignment of thread objects for biased locking
172 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
173 if (UseBiasedLocking) {
174 const int alignment = markOopDesc::biased_lock_alignment;
175 size_t aligned_size = size + (alignment - sizeof(intptr_t));
176 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
177 : AllocateHeap(aligned_size, flags, CURRENT_PC,
178 AllocFailStrategy::RETURN_NULL);
179 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
180 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
181 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
182 "JavaThread alignment code overflowed allocated storage");
183 if (TraceBiasedLocking) {
184 if (aligned_addr != real_malloc_addr)
185 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
186 real_malloc_addr, aligned_addr);
187 }
188 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
189 return aligned_addr;
190 } else {
191 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
192 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
193 }
194 }
196 void Thread::operator delete(void* p) {
197 if (UseBiasedLocking) {
198 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
199 FreeHeap(real_malloc_addr, mtThread);
200 } else {
201 FreeHeap(p, mtThread);
202 }
203 }
206 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
207 // JavaThread
210 Thread::Thread() {
211 // stack and get_thread
212 set_stack_base(NULL);
213 set_stack_size(0);
214 set_self_raw_id(0);
215 set_lgrp_id(-1);
217 // allocated data structures
218 set_osthread(NULL);
219 set_resource_area(new (mtThread)ResourceArea());
220 set_handle_area(new (mtThread) HandleArea(NULL));
221 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(300, true));
222 set_active_handles(NULL);
223 set_free_handle_block(NULL);
224 set_last_handle_mark(NULL);
226 // This initial value ==> never claimed.
227 _oops_do_parity = 0;
229 // the handle mark links itself to last_handle_mark
230 new HandleMark(this);
232 // plain initialization
233 debug_only(_owned_locks = NULL;)
234 debug_only(_allow_allocation_count = 0;)
235 NOT_PRODUCT(_allow_safepoint_count = 0;)
236 NOT_PRODUCT(_skip_gcalot = false;)
237 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
238 _jvmti_env_iteration_count = 0;
239 set_allocated_bytes(0);
240 set_trace_buffer(NULL);
241 _vm_operation_started_count = 0;
242 _vm_operation_completed_count = 0;
243 _current_pending_monitor = NULL;
244 _current_pending_monitor_is_from_java = true;
245 _current_waiting_monitor = NULL;
246 _num_nested_signal = 0;
247 omFreeList = NULL ;
248 omFreeCount = 0 ;
249 omFreeProvision = 32 ;
250 omInUseList = NULL ;
251 omInUseCount = 0 ;
253 #ifdef ASSERT
254 _visited_for_critical_count = false;
255 #endif
257 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
258 _suspend_flags = 0;
260 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
261 _hashStateX = os::random() ;
262 _hashStateY = 842502087 ;
263 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
264 _hashStateW = 273326509 ;
266 _OnTrap = 0 ;
267 _schedctl = NULL ;
268 _Stalled = 0 ;
269 _TypeTag = 0x2BAD ;
271 // Many of the following fields are effectively final - immutable
272 // Note that nascent threads can't use the Native Monitor-Mutex
273 // construct until the _MutexEvent is initialized ...
274 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
275 // we might instead use a stack of ParkEvents that we could provision on-demand.
276 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
277 // and ::Release()
278 _ParkEvent = ParkEvent::Allocate (this) ;
279 _SleepEvent = ParkEvent::Allocate (this) ;
280 _MutexEvent = ParkEvent::Allocate (this) ;
281 _MuxEvent = ParkEvent::Allocate (this) ;
283 #ifdef CHECK_UNHANDLED_OOPS
284 if (CheckUnhandledOops) {
285 _unhandled_oops = new UnhandledOops(this);
286 }
287 #endif // CHECK_UNHANDLED_OOPS
288 #ifdef ASSERT
289 if (UseBiasedLocking) {
290 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
291 assert(this == _real_malloc_address ||
292 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
293 "bug in forced alignment of thread objects");
294 }
295 #endif /* ASSERT */
296 }
298 void Thread::initialize_thread_local_storage() {
299 // Note: Make sure this method only calls
300 // non-blocking operations. Otherwise, it might not work
301 // with the thread-startup/safepoint interaction.
303 // During Java thread startup, safepoint code should allow this
304 // method to complete because it may need to allocate memory to
305 // store information for the new thread.
307 // initialize structure dependent on thread local storage
308 ThreadLocalStorage::set_thread(this);
309 }
311 void Thread::record_stack_base_and_size() {
312 set_stack_base(os::current_stack_base());
313 set_stack_size(os::current_stack_size());
314 // CR 7190089: on Solaris, primordial thread's stack is adjusted
315 // in initialize_thread(). Without the adjustment, stack size is
316 // incorrect if stack is set to unlimited (ulimit -s unlimited).
317 // So far, only Solaris has real implementation of initialize_thread().
318 //
319 // set up any platform-specific state.
320 os::initialize_thread(this);
322 #if INCLUDE_NMT
323 // record thread's native stack, stack grows downward
324 address stack_low_addr = stack_base() - stack_size();
325 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this,
326 CURRENT_PC);
327 #endif // INCLUDE_NMT
328 }
331 Thread::~Thread() {
332 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
333 ObjectSynchronizer::omFlush (this) ;
335 // stack_base can be NULL if the thread is never started or exited before
336 // record_stack_base_and_size called. Although, we would like to ensure
337 // that all started threads do call record_stack_base_and_size(), there is
338 // not proper way to enforce that.
339 #if INCLUDE_NMT
340 if (_stack_base != NULL) {
341 address low_stack_addr = stack_base() - stack_size();
342 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this);
343 #ifdef ASSERT
344 set_stack_base(NULL);
345 #endif
346 }
347 #endif // INCLUDE_NMT
349 // deallocate data structures
350 delete resource_area();
351 // since the handle marks are using the handle area, we have to deallocated the root
352 // handle mark before deallocating the thread's handle area,
353 assert(last_handle_mark() != NULL, "check we have an element");
354 delete last_handle_mark();
355 assert(last_handle_mark() == NULL, "check we have reached the end");
357 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
358 // We NULL out the fields for good hygiene.
359 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
360 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
361 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
362 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
364 delete handle_area();
365 delete metadata_handles();
367 // osthread() can be NULL, if creation of thread failed.
368 if (osthread() != NULL) os::free_thread(osthread());
370 delete _SR_lock;
372 // clear thread local storage if the Thread is deleting itself
373 if (this == Thread::current()) {
374 ThreadLocalStorage::set_thread(NULL);
375 } else {
376 // In the case where we're not the current thread, invalidate all the
377 // caches in case some code tries to get the current thread or the
378 // thread that was destroyed, and gets stale information.
379 ThreadLocalStorage::invalidate_all();
380 }
381 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
382 }
384 // NOTE: dummy function for assertion purpose.
385 void Thread::run() {
386 ShouldNotReachHere();
387 }
389 #ifdef ASSERT
390 // Private method to check for dangling thread pointer
391 void check_for_dangling_thread_pointer(Thread *thread) {
392 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
393 "possibility of dangling Thread pointer");
394 }
395 #endif
398 #ifndef PRODUCT
399 // Tracing method for basic thread operations
400 void Thread::trace(const char* msg, const Thread* const thread) {
401 if (!TraceThreadEvents) return;
402 ResourceMark rm;
403 ThreadCritical tc;
404 const char *name = "non-Java thread";
405 int prio = -1;
406 if (thread->is_Java_thread()
407 && !thread->is_Compiler_thread()) {
408 // The Threads_lock must be held to get information about
409 // this thread but may not be in some situations when
410 // tracing thread events.
411 bool release_Threads_lock = false;
412 if (!Threads_lock->owned_by_self()) {
413 Threads_lock->lock();
414 release_Threads_lock = true;
415 }
416 JavaThread* jt = (JavaThread *)thread;
417 name = (char *)jt->get_thread_name();
418 oop thread_oop = jt->threadObj();
419 if (thread_oop != NULL) {
420 prio = java_lang_Thread::priority(thread_oop);
421 }
422 if (release_Threads_lock) {
423 Threads_lock->unlock();
424 }
425 }
426 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
427 }
428 #endif
431 ThreadPriority Thread::get_priority(const Thread* const thread) {
432 trace("get priority", thread);
433 ThreadPriority priority;
434 // Can return an error!
435 (void)os::get_priority(thread, priority);
436 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
437 return priority;
438 }
440 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
441 trace("set priority", thread);
442 debug_only(check_for_dangling_thread_pointer(thread);)
443 // Can return an error!
444 (void)os::set_priority(thread, priority);
445 }
448 void Thread::start(Thread* thread) {
449 trace("start", thread);
450 // Start is different from resume in that its safety is guaranteed by context or
451 // being called from a Java method synchronized on the Thread object.
452 if (!DisableStartThread) {
453 if (thread->is_Java_thread()) {
454 // Initialize the thread state to RUNNABLE before starting this thread.
455 // Can not set it after the thread started because we do not know the
456 // exact thread state at that time. It could be in MONITOR_WAIT or
457 // in SLEEPING or some other state.
458 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
459 java_lang_Thread::RUNNABLE);
460 }
461 os::start_thread(thread);
462 }
463 }
465 // Enqueue a VM_Operation to do the job for us - sometime later
466 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
467 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
468 VMThread::execute(vm_stop);
469 }
472 //
473 // Check if an external suspend request has completed (or has been
474 // cancelled). Returns true if the thread is externally suspended and
475 // false otherwise.
476 //
477 // The bits parameter returns information about the code path through
478 // the routine. Useful for debugging:
479 //
480 // set in is_ext_suspend_completed():
481 // 0x00000001 - routine was entered
482 // 0x00000010 - routine return false at end
483 // 0x00000100 - thread exited (return false)
484 // 0x00000200 - suspend request cancelled (return false)
485 // 0x00000400 - thread suspended (return true)
486 // 0x00001000 - thread is in a suspend equivalent state (return true)
487 // 0x00002000 - thread is native and walkable (return true)
488 // 0x00004000 - thread is native_trans and walkable (needed retry)
489 //
490 // set in wait_for_ext_suspend_completion():
491 // 0x00010000 - routine was entered
492 // 0x00020000 - suspend request cancelled before loop (return false)
493 // 0x00040000 - thread suspended before loop (return true)
494 // 0x00080000 - suspend request cancelled in loop (return false)
495 // 0x00100000 - thread suspended in loop (return true)
496 // 0x00200000 - suspend not completed during retry loop (return false)
497 //
499 // Helper class for tracing suspend wait debug bits.
500 //
501 // 0x00000100 indicates that the target thread exited before it could
502 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
503 // 0x00080000 each indicate a cancelled suspend request so they don't
504 // count as wait failures either.
505 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
507 class TraceSuspendDebugBits : public StackObj {
508 private:
509 JavaThread * jt;
510 bool is_wait;
511 bool called_by_wait; // meaningful when !is_wait
512 uint32_t * bits;
514 public:
515 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
516 uint32_t *_bits) {
517 jt = _jt;
518 is_wait = _is_wait;
519 called_by_wait = _called_by_wait;
520 bits = _bits;
521 }
523 ~TraceSuspendDebugBits() {
524 if (!is_wait) {
525 #if 1
526 // By default, don't trace bits for is_ext_suspend_completed() calls.
527 // That trace is very chatty.
528 return;
529 #else
530 if (!called_by_wait) {
531 // If tracing for is_ext_suspend_completed() is enabled, then only
532 // trace calls to it from wait_for_ext_suspend_completion()
533 return;
534 }
535 #endif
536 }
538 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
539 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
540 MutexLocker ml(Threads_lock); // needed for get_thread_name()
541 ResourceMark rm;
543 tty->print_cr(
544 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
545 jt->get_thread_name(), *bits);
547 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
548 }
549 }
550 }
551 };
552 #undef DEBUG_FALSE_BITS
555 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
556 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
558 bool did_trans_retry = false; // only do thread_in_native_trans retry once
559 bool do_trans_retry; // flag to force the retry
561 *bits |= 0x00000001;
563 do {
564 do_trans_retry = false;
566 if (is_exiting()) {
567 // Thread is in the process of exiting. This is always checked
568 // first to reduce the risk of dereferencing a freed JavaThread.
569 *bits |= 0x00000100;
570 return false;
571 }
573 if (!is_external_suspend()) {
574 // Suspend request is cancelled. This is always checked before
575 // is_ext_suspended() to reduce the risk of a rogue resume
576 // confusing the thread that made the suspend request.
577 *bits |= 0x00000200;
578 return false;
579 }
581 if (is_ext_suspended()) {
582 // thread is suspended
583 *bits |= 0x00000400;
584 return true;
585 }
587 // Now that we no longer do hard suspends of threads running
588 // native code, the target thread can be changing thread state
589 // while we are in this routine:
590 //
591 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
592 //
593 // We save a copy of the thread state as observed at this moment
594 // and make our decision about suspend completeness based on the
595 // copy. This closes the race where the thread state is seen as
596 // _thread_in_native_trans in the if-thread_blocked check, but is
597 // seen as _thread_blocked in if-thread_in_native_trans check.
598 JavaThreadState save_state = thread_state();
600 if (save_state == _thread_blocked && is_suspend_equivalent()) {
601 // If the thread's state is _thread_blocked and this blocking
602 // condition is known to be equivalent to a suspend, then we can
603 // consider the thread to be externally suspended. This means that
604 // the code that sets _thread_blocked has been modified to do
605 // self-suspension if the blocking condition releases. We also
606 // used to check for CONDVAR_WAIT here, but that is now covered by
607 // the _thread_blocked with self-suspension check.
608 //
609 // Return true since we wouldn't be here unless there was still an
610 // external suspend request.
611 *bits |= 0x00001000;
612 return true;
613 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
614 // Threads running native code will self-suspend on native==>VM/Java
615 // transitions. If its stack is walkable (should always be the case
616 // unless this function is called before the actual java_suspend()
617 // call), then the wait is done.
618 *bits |= 0x00002000;
619 return true;
620 } else if (!called_by_wait && !did_trans_retry &&
621 save_state == _thread_in_native_trans &&
622 frame_anchor()->walkable()) {
623 // The thread is transitioning from thread_in_native to another
624 // thread state. check_safepoint_and_suspend_for_native_trans()
625 // will force the thread to self-suspend. If it hasn't gotten
626 // there yet we may have caught the thread in-between the native
627 // code check above and the self-suspend. Lucky us. If we were
628 // called by wait_for_ext_suspend_completion(), then it
629 // will be doing the retries so we don't have to.
630 //
631 // Since we use the saved thread state in the if-statement above,
632 // there is a chance that the thread has already transitioned to
633 // _thread_blocked by the time we get here. In that case, we will
634 // make a single unnecessary pass through the logic below. This
635 // doesn't hurt anything since we still do the trans retry.
637 *bits |= 0x00004000;
639 // Once the thread leaves thread_in_native_trans for another
640 // thread state, we break out of this retry loop. We shouldn't
641 // need this flag to prevent us from getting back here, but
642 // sometimes paranoia is good.
643 did_trans_retry = true;
645 // We wait for the thread to transition to a more usable state.
646 for (int i = 1; i <= SuspendRetryCount; i++) {
647 // We used to do an "os::yield_all(i)" call here with the intention
648 // that yielding would increase on each retry. However, the parameter
649 // is ignored on Linux which means the yield didn't scale up. Waiting
650 // on the SR_lock below provides a much more predictable scale up for
651 // the delay. It also provides a simple/direct point to check for any
652 // safepoint requests from the VMThread
654 // temporarily drops SR_lock while doing wait with safepoint check
655 // (if we're a JavaThread - the WatcherThread can also call this)
656 // and increase delay with each retry
657 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
659 // check the actual thread state instead of what we saved above
660 if (thread_state() != _thread_in_native_trans) {
661 // the thread has transitioned to another thread state so
662 // try all the checks (except this one) one more time.
663 do_trans_retry = true;
664 break;
665 }
666 } // end retry loop
669 }
670 } while (do_trans_retry);
672 *bits |= 0x00000010;
673 return false;
674 }
676 //
677 // Wait for an external suspend request to complete (or be cancelled).
678 // Returns true if the thread is externally suspended and false otherwise.
679 //
680 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
681 uint32_t *bits) {
682 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
683 false /* !called_by_wait */, bits);
685 // local flag copies to minimize SR_lock hold time
686 bool is_suspended;
687 bool pending;
688 uint32_t reset_bits;
690 // set a marker so is_ext_suspend_completed() knows we are the caller
691 *bits |= 0x00010000;
693 // We use reset_bits to reinitialize the bits value at the top of
694 // each retry loop. This allows the caller to make use of any
695 // unused bits for their own marking purposes.
696 reset_bits = *bits;
698 {
699 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
700 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
701 delay, bits);
702 pending = is_external_suspend();
703 }
704 // must release SR_lock to allow suspension to complete
706 if (!pending) {
707 // A cancelled suspend request is the only false return from
708 // is_ext_suspend_completed() that keeps us from entering the
709 // retry loop.
710 *bits |= 0x00020000;
711 return false;
712 }
714 if (is_suspended) {
715 *bits |= 0x00040000;
716 return true;
717 }
719 for (int i = 1; i <= retries; i++) {
720 *bits = reset_bits; // reinit to only track last retry
722 // We used to do an "os::yield_all(i)" call here with the intention
723 // that yielding would increase on each retry. However, the parameter
724 // is ignored on Linux which means the yield didn't scale up. Waiting
725 // on the SR_lock below provides a much more predictable scale up for
726 // the delay. It also provides a simple/direct point to check for any
727 // safepoint requests from the VMThread
729 {
730 MutexLocker ml(SR_lock());
731 // wait with safepoint check (if we're a JavaThread - the WatcherThread
732 // can also call this) and increase delay with each retry
733 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
735 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
736 delay, bits);
738 // It is possible for the external suspend request to be cancelled
739 // (by a resume) before the actual suspend operation is completed.
740 // Refresh our local copy to see if we still need to wait.
741 pending = is_external_suspend();
742 }
744 if (!pending) {
745 // A cancelled suspend request is the only false return from
746 // is_ext_suspend_completed() that keeps us from staying in the
747 // retry loop.
748 *bits |= 0x00080000;
749 return false;
750 }
752 if (is_suspended) {
753 *bits |= 0x00100000;
754 return true;
755 }
756 } // end retry loop
758 // thread did not suspend after all our retries
759 *bits |= 0x00200000;
760 return false;
761 }
763 #ifndef PRODUCT
764 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
766 // This should not need to be atomic as the only way for simultaneous
767 // updates is via interrupts. Even then this should be rare or non-existant
768 // and we don't care that much anyway.
770 int index = _jmp_ring_index;
771 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
772 _jmp_ring[index]._target = (intptr_t) target;
773 _jmp_ring[index]._instruction = (intptr_t) instr;
774 _jmp_ring[index]._file = file;
775 _jmp_ring[index]._line = line;
776 }
777 #endif /* PRODUCT */
779 // Called by flat profiler
780 // Callers have already called wait_for_ext_suspend_completion
781 // The assertion for that is currently too complex to put here:
782 bool JavaThread::profile_last_Java_frame(frame* _fr) {
783 bool gotframe = false;
784 // self suspension saves needed state.
785 if (has_last_Java_frame() && _anchor.walkable()) {
786 *_fr = pd_last_frame();
787 gotframe = true;
788 }
789 return gotframe;
790 }
792 void Thread::interrupt(Thread* thread) {
793 trace("interrupt", thread);
794 debug_only(check_for_dangling_thread_pointer(thread);)
795 os::interrupt(thread);
796 }
798 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
799 trace("is_interrupted", thread);
800 debug_only(check_for_dangling_thread_pointer(thread);)
801 // Note: If clear_interrupted==false, this simply fetches and
802 // returns the value of the field osthread()->interrupted().
803 return os::is_interrupted(thread, clear_interrupted);
804 }
807 // GC Support
808 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
809 jint thread_parity = _oops_do_parity;
810 if (thread_parity != strong_roots_parity) {
811 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
812 if (res == thread_parity) {
813 return true;
814 } else {
815 guarantee(res == strong_roots_parity, "Or else what?");
816 assert(SharedHeap::heap()->workers()->active_workers() > 0,
817 "Should only fail when parallel.");
818 return false;
819 }
820 }
821 assert(SharedHeap::heap()->workers()->active_workers() > 0,
822 "Should only fail when parallel.");
823 return false;
824 }
826 void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
827 active_handles()->oops_do(f);
828 // Do oop for ThreadShadow
829 f->do_oop((oop*)&_pending_exception);
830 handle_area()->oops_do(f);
831 }
833 void Thread::nmethods_do(CodeBlobClosure* cf) {
834 // no nmethods in a generic thread...
835 }
837 void Thread::metadata_do(void f(Metadata*)) {
838 if (metadata_handles() != NULL) {
839 for (int i = 0; i< metadata_handles()->length(); i++) {
840 f(metadata_handles()->at(i));
841 }
842 }
843 }
845 void Thread::print_on(outputStream* st) const {
846 // get_priority assumes osthread initialized
847 if (osthread() != NULL) {
848 int os_prio;
849 if (os::get_native_priority(this, &os_prio) == OS_OK) {
850 st->print("os_prio=%d ", os_prio);
851 }
852 st->print("tid=" INTPTR_FORMAT " ", this);
853 osthread()->print_on(st);
854 }
855 debug_only(if (WizardMode) print_owned_locks_on(st);)
856 }
858 // Thread::print_on_error() is called by fatal error handler. Don't use
859 // any lock or allocate memory.
860 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
861 if (is_VM_thread()) st->print("VMThread");
862 else if (is_Compiler_thread()) st->print("CompilerThread");
863 else if (is_Java_thread()) st->print("JavaThread");
864 else if (is_GC_task_thread()) st->print("GCTaskThread");
865 else if (is_Watcher_thread()) st->print("WatcherThread");
866 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
867 else st->print("Thread");
869 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
870 _stack_base - _stack_size, _stack_base);
872 if (osthread()) {
873 st->print(" [id=%d]", osthread()->thread_id());
874 }
875 }
877 #ifdef ASSERT
878 void Thread::print_owned_locks_on(outputStream* st) const {
879 Monitor *cur = _owned_locks;
880 if (cur == NULL) {
881 st->print(" (no locks) ");
882 } else {
883 st->print_cr(" Locks owned:");
884 while(cur) {
885 cur->print_on(st);
886 cur = cur->next();
887 }
888 }
889 }
891 static int ref_use_count = 0;
893 bool Thread::owns_locks_but_compiled_lock() const {
894 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
895 if (cur != Compile_lock) return true;
896 }
897 return false;
898 }
901 #endif
903 #ifndef PRODUCT
905 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
906 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
907 // no threads which allow_vm_block's are held
908 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
909 // Check if current thread is allowed to block at a safepoint
910 if (!(_allow_safepoint_count == 0))
911 fatal("Possible safepoint reached by thread that does not allow it");
912 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
913 fatal("LEAF method calling lock?");
914 }
916 #ifdef ASSERT
917 if (potential_vm_operation && is_Java_thread()
918 && !Universe::is_bootstrapping()) {
919 // Make sure we do not hold any locks that the VM thread also uses.
920 // This could potentially lead to deadlocks
921 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
922 // Threads_lock is special, since the safepoint synchronization will not start before this is
923 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
924 // since it is used to transfer control between JavaThreads and the VMThread
925 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
926 if ( (cur->allow_vm_block() &&
927 cur != Threads_lock &&
928 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
929 cur != VMOperationRequest_lock &&
930 cur != VMOperationQueue_lock) ||
931 cur->rank() == Mutex::special) {
932 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
933 }
934 }
935 }
937 if (GCALotAtAllSafepoints) {
938 // We could enter a safepoint here and thus have a gc
939 InterfaceSupport::check_gc_alot();
940 }
941 #endif
942 }
943 #endif
945 bool Thread::is_in_stack(address adr) const {
946 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
947 address end = os::current_stack_pointer();
948 // Allow non Java threads to call this without stack_base
949 if (_stack_base == NULL) return true;
950 if (stack_base() >= adr && adr >= end) return true;
952 return false;
953 }
956 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
957 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
958 // used for compilation in the future. If that change is made, the need for these methods
959 // should be revisited, and they should be removed if possible.
961 bool Thread::is_lock_owned(address adr) const {
962 return on_local_stack(adr);
963 }
965 bool Thread::set_as_starting_thread() {
966 // NOTE: this must be called inside the main thread.
967 return os::create_main_thread((JavaThread*)this);
968 }
970 static void initialize_class(Symbol* class_name, TRAPS) {
971 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
972 InstanceKlass::cast(klass)->initialize(CHECK);
973 }
976 // Creates the initial ThreadGroup
977 static Handle create_initial_thread_group(TRAPS) {
978 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
979 instanceKlassHandle klass (THREAD, k);
981 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
982 {
983 JavaValue result(T_VOID);
984 JavaCalls::call_special(&result,
985 system_instance,
986 klass,
987 vmSymbols::object_initializer_name(),
988 vmSymbols::void_method_signature(),
989 CHECK_NH);
990 }
991 Universe::set_system_thread_group(system_instance());
993 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
994 {
995 JavaValue result(T_VOID);
996 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
997 JavaCalls::call_special(&result,
998 main_instance,
999 klass,
1000 vmSymbols::object_initializer_name(),
1001 vmSymbols::threadgroup_string_void_signature(),
1002 system_instance,
1003 string,
1004 CHECK_NH);
1005 }
1006 return main_instance;
1007 }
1009 // Creates the initial Thread
1010 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1011 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1012 instanceKlassHandle klass (THREAD, k);
1013 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1015 java_lang_Thread::set_thread(thread_oop(), thread);
1016 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1017 thread->set_threadObj(thread_oop());
1019 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1021 JavaValue result(T_VOID);
1022 JavaCalls::call_special(&result, thread_oop,
1023 klass,
1024 vmSymbols::object_initializer_name(),
1025 vmSymbols::threadgroup_string_void_signature(),
1026 thread_group,
1027 string,
1028 CHECK_NULL);
1029 return thread_oop();
1030 }
1032 static void call_initializeSystemClass(TRAPS) {
1033 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1034 instanceKlassHandle klass (THREAD, k);
1036 JavaValue result(T_VOID);
1037 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1038 vmSymbols::void_method_signature(), CHECK);
1039 }
1041 char java_runtime_name[128] = "";
1042 char java_runtime_version[128] = "";
1044 // extract the JRE name from sun.misc.Version.java_runtime_name
1045 static const char* get_java_runtime_name(TRAPS) {
1046 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1047 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1048 fieldDescriptor fd;
1049 bool found = k != NULL &&
1050 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1051 vmSymbols::string_signature(), &fd);
1052 if (found) {
1053 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1054 if (name_oop == NULL)
1055 return NULL;
1056 const char* name = java_lang_String::as_utf8_string(name_oop,
1057 java_runtime_name,
1058 sizeof(java_runtime_name));
1059 return name;
1060 } else {
1061 return NULL;
1062 }
1063 }
1065 // extract the JRE version from sun.misc.Version.java_runtime_version
1066 static const char* get_java_runtime_version(TRAPS) {
1067 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1068 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1069 fieldDescriptor fd;
1070 bool found = k != NULL &&
1071 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1072 vmSymbols::string_signature(), &fd);
1073 if (found) {
1074 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1075 if (name_oop == NULL)
1076 return NULL;
1077 const char* name = java_lang_String::as_utf8_string(name_oop,
1078 java_runtime_version,
1079 sizeof(java_runtime_version));
1080 return name;
1081 } else {
1082 return NULL;
1083 }
1084 }
1086 // General purpose hook into Java code, run once when the VM is initialized.
1087 // The Java library method itself may be changed independently from the VM.
1088 static void call_postVMInitHook(TRAPS) {
1089 Klass* k = SystemDictionary::PostVMInitHook_klass();
1090 instanceKlassHandle klass (THREAD, k);
1091 if (klass.not_null()) {
1092 JavaValue result(T_VOID);
1093 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1094 vmSymbols::void_method_signature(),
1095 CHECK);
1096 }
1097 }
1099 static void reset_vm_info_property(TRAPS) {
1100 // the vm info string
1101 ResourceMark rm(THREAD);
1102 const char *vm_info = VM_Version::vm_info_string();
1104 // java.lang.System class
1105 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1106 instanceKlassHandle klass (THREAD, k);
1108 // setProperty arguments
1109 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1110 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1112 // return value
1113 JavaValue r(T_OBJECT);
1115 // public static String setProperty(String key, String value);
1116 JavaCalls::call_static(&r,
1117 klass,
1118 vmSymbols::setProperty_name(),
1119 vmSymbols::string_string_string_signature(),
1120 key_str,
1121 value_str,
1122 CHECK);
1123 }
1126 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1127 assert(thread_group.not_null(), "thread group should be specified");
1128 assert(threadObj() == NULL, "should only create Java thread object once");
1130 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1131 instanceKlassHandle klass (THREAD, k);
1132 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1134 java_lang_Thread::set_thread(thread_oop(), this);
1135 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1136 set_threadObj(thread_oop());
1138 JavaValue result(T_VOID);
1139 if (thread_name != NULL) {
1140 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1141 // Thread gets assigned specified name and null target
1142 JavaCalls::call_special(&result,
1143 thread_oop,
1144 klass,
1145 vmSymbols::object_initializer_name(),
1146 vmSymbols::threadgroup_string_void_signature(),
1147 thread_group, // Argument 1
1148 name, // Argument 2
1149 THREAD);
1150 } else {
1151 // Thread gets assigned name "Thread-nnn" and null target
1152 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1153 JavaCalls::call_special(&result,
1154 thread_oop,
1155 klass,
1156 vmSymbols::object_initializer_name(),
1157 vmSymbols::threadgroup_runnable_void_signature(),
1158 thread_group, // Argument 1
1159 Handle(), // Argument 2
1160 THREAD);
1161 }
1164 if (daemon) {
1165 java_lang_Thread::set_daemon(thread_oop());
1166 }
1168 if (HAS_PENDING_EXCEPTION) {
1169 return;
1170 }
1172 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1173 Handle threadObj(this, this->threadObj());
1175 JavaCalls::call_special(&result,
1176 thread_group,
1177 group,
1178 vmSymbols::add_method_name(),
1179 vmSymbols::thread_void_signature(),
1180 threadObj, // Arg 1
1181 THREAD);
1184 }
1186 // NamedThread -- non-JavaThread subclasses with multiple
1187 // uniquely named instances should derive from this.
1188 NamedThread::NamedThread() : Thread() {
1189 _name = NULL;
1190 _processed_thread = NULL;
1191 }
1193 NamedThread::~NamedThread() {
1194 if (_name != NULL) {
1195 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1196 _name = NULL;
1197 }
1198 }
1200 void NamedThread::set_name(const char* format, ...) {
1201 guarantee(_name == NULL, "Only get to set name once.");
1202 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1203 guarantee(_name != NULL, "alloc failure");
1204 va_list ap;
1205 va_start(ap, format);
1206 jio_vsnprintf(_name, max_name_len, format, ap);
1207 va_end(ap);
1208 }
1210 // ======= WatcherThread ========
1212 // The watcher thread exists to simulate timer interrupts. It should
1213 // be replaced by an abstraction over whatever native support for
1214 // timer interrupts exists on the platform.
1216 WatcherThread* WatcherThread::_watcher_thread = NULL;
1217 bool WatcherThread::_startable = false;
1218 volatile bool WatcherThread::_should_terminate = false;
1220 WatcherThread::WatcherThread() : Thread() {
1221 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1222 if (os::create_thread(this, os::watcher_thread)) {
1223 _watcher_thread = this;
1225 // Set the watcher thread to the highest OS priority which should not be
1226 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1227 // is created. The only normal thread using this priority is the reference
1228 // handler thread, which runs for very short intervals only.
1229 // If the VMThread's priority is not lower than the WatcherThread profiling
1230 // will be inaccurate.
1231 os::set_priority(this, MaxPriority);
1232 if (!DisableStartThread) {
1233 os::start_thread(this);
1234 }
1235 }
1236 }
1238 int WatcherThread::sleep() const {
1239 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1241 // remaining will be zero if there are no tasks,
1242 // causing the WatcherThread to sleep until a task is
1243 // enrolled
1244 int remaining = PeriodicTask::time_to_wait();
1245 int time_slept = 0;
1247 // we expect this to timeout - we only ever get unparked when
1248 // we should terminate or when a new task has been enrolled
1249 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1251 jlong time_before_loop = os::javaTimeNanos();
1253 for (;;) {
1254 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1255 jlong now = os::javaTimeNanos();
1257 if (remaining == 0) {
1258 // if we didn't have any tasks we could have waited for a long time
1259 // consider the time_slept zero and reset time_before_loop
1260 time_slept = 0;
1261 time_before_loop = now;
1262 } else {
1263 // need to recalulate since we might have new tasks in _tasks
1264 time_slept = (int) ((now - time_before_loop) / 1000000);
1265 }
1267 // Change to task list or spurious wakeup of some kind
1268 if (timedout || _should_terminate) {
1269 break;
1270 }
1272 remaining = PeriodicTask::time_to_wait();
1273 if (remaining == 0) {
1274 // Last task was just disenrolled so loop around and wait until
1275 // another task gets enrolled
1276 continue;
1277 }
1279 remaining -= time_slept;
1280 if (remaining <= 0)
1281 break;
1282 }
1284 return time_slept;
1285 }
1287 void WatcherThread::run() {
1288 assert(this == watcher_thread(), "just checking");
1290 this->record_stack_base_and_size();
1291 this->initialize_thread_local_storage();
1292 this->set_active_handles(JNIHandleBlock::allocate_block());
1293 while(!_should_terminate) {
1294 assert(watcher_thread() == Thread::current(), "thread consistency check");
1295 assert(watcher_thread() == this, "thread consistency check");
1297 // Calculate how long it'll be until the next PeriodicTask work
1298 // should be done, and sleep that amount of time.
1299 int time_waited = sleep();
1301 if (is_error_reported()) {
1302 // A fatal error has happened, the error handler(VMError::report_and_die)
1303 // should abort JVM after creating an error log file. However in some
1304 // rare cases, the error handler itself might deadlock. Here we try to
1305 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1306 //
1307 // This code is in WatcherThread because WatcherThread wakes up
1308 // periodically so the fatal error handler doesn't need to do anything;
1309 // also because the WatcherThread is less likely to crash than other
1310 // threads.
1312 for (;;) {
1313 if (!ShowMessageBoxOnError
1314 && (OnError == NULL || OnError[0] == '\0')
1315 && Arguments::abort_hook() == NULL) {
1316 os::sleep(this, 2 * 60 * 1000, false);
1317 fdStream err(defaultStream::output_fd());
1318 err.print_raw_cr("# [ timer expired, abort... ]");
1319 // skip atexit/vm_exit/vm_abort hooks
1320 os::die();
1321 }
1323 // Wake up 5 seconds later, the fatal handler may reset OnError or
1324 // ShowMessageBoxOnError when it is ready to abort.
1325 os::sleep(this, 5 * 1000, false);
1326 }
1327 }
1329 PeriodicTask::real_time_tick(time_waited);
1330 }
1332 // Signal that it is terminated
1333 {
1334 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1335 _watcher_thread = NULL;
1336 Terminator_lock->notify();
1337 }
1339 // Thread destructor usually does this..
1340 ThreadLocalStorage::set_thread(NULL);
1341 }
1343 void WatcherThread::start() {
1344 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1346 if (watcher_thread() == NULL && _startable) {
1347 _should_terminate = false;
1348 // Create the single instance of WatcherThread
1349 new WatcherThread();
1350 }
1351 }
1353 void WatcherThread::make_startable() {
1354 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1355 _startable = true;
1356 }
1358 void WatcherThread::stop() {
1359 {
1360 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1361 _should_terminate = true;
1362 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1364 WatcherThread* watcher = watcher_thread();
1365 if (watcher != NULL)
1366 watcher->unpark();
1367 }
1369 // it is ok to take late safepoints here, if needed
1370 MutexLocker mu(Terminator_lock);
1372 while(watcher_thread() != NULL) {
1373 // This wait should make safepoint checks, wait without a timeout,
1374 // and wait as a suspend-equivalent condition.
1375 //
1376 // Note: If the FlatProfiler is running, then this thread is waiting
1377 // for the WatcherThread to terminate and the WatcherThread, via the
1378 // FlatProfiler task, is waiting for the external suspend request on
1379 // this thread to complete. wait_for_ext_suspend_completion() will
1380 // eventually timeout, but that takes time. Making this wait a
1381 // suspend-equivalent condition solves that timeout problem.
1382 //
1383 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1384 Mutex::_as_suspend_equivalent_flag);
1385 }
1386 }
1388 void WatcherThread::unpark() {
1389 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1390 PeriodicTask_lock->notify();
1391 }
1393 void WatcherThread::print_on(outputStream* st) const {
1394 st->print("\"%s\" ", name());
1395 Thread::print_on(st);
1396 st->cr();
1397 }
1399 // ======= JavaThread ========
1401 // A JavaThread is a normal Java thread
1403 void JavaThread::initialize() {
1404 // Initialize fields
1406 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1407 set_claimed_par_id(-1);
1409 set_saved_exception_pc(NULL);
1410 set_threadObj(NULL);
1411 _anchor.clear();
1412 set_entry_point(NULL);
1413 set_jni_functions(jni_functions());
1414 set_callee_target(NULL);
1415 set_vm_result(NULL);
1416 set_vm_result_2(NULL);
1417 set_vframe_array_head(NULL);
1418 set_vframe_array_last(NULL);
1419 set_deferred_locals(NULL);
1420 set_deopt_mark(NULL);
1421 set_deopt_nmethod(NULL);
1422 clear_must_deopt_id();
1423 set_monitor_chunks(NULL);
1424 set_next(NULL);
1425 set_thread_state(_thread_new);
1426 #if INCLUDE_NMT
1427 set_recorder(NULL);
1428 #endif
1429 _terminated = _not_terminated;
1430 _privileged_stack_top = NULL;
1431 _array_for_gc = NULL;
1432 _suspend_equivalent = false;
1433 _in_deopt_handler = 0;
1434 _doing_unsafe_access = false;
1435 _stack_guard_state = stack_guard_unused;
1436 _exception_oop = NULL;
1437 _exception_pc = 0;
1438 _exception_handler_pc = 0;
1439 _is_method_handle_return = 0;
1440 _jvmti_thread_state= NULL;
1441 _should_post_on_exceptions_flag = JNI_FALSE;
1442 _jvmti_get_loaded_classes_closure = NULL;
1443 _interp_only_mode = 0;
1444 _special_runtime_exit_condition = _no_async_condition;
1445 _pending_async_exception = NULL;
1446 _is_compiling = false;
1447 _thread_stat = NULL;
1448 _thread_stat = new ThreadStatistics();
1449 _blocked_on_compilation = false;
1450 _jni_active_critical = 0;
1451 _do_not_unlock_if_synchronized = false;
1452 _cached_monitor_info = NULL;
1453 _parker = Parker::Allocate(this) ;
1455 #ifndef PRODUCT
1456 _jmp_ring_index = 0;
1457 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1458 record_jump(NULL, NULL, NULL, 0);
1459 }
1460 #endif /* PRODUCT */
1462 set_thread_profiler(NULL);
1463 if (FlatProfiler::is_active()) {
1464 // This is where we would decide to either give each thread it's own profiler
1465 // or use one global one from FlatProfiler,
1466 // or up to some count of the number of profiled threads, etc.
1467 ThreadProfiler* pp = new ThreadProfiler();
1468 pp->engage();
1469 set_thread_profiler(pp);
1470 }
1472 // Setup safepoint state info for this thread
1473 ThreadSafepointState::create(this);
1475 debug_only(_java_call_counter = 0);
1477 // JVMTI PopFrame support
1478 _popframe_condition = popframe_inactive;
1479 _popframe_preserved_args = NULL;
1480 _popframe_preserved_args_size = 0;
1482 pd_initialize();
1483 }
1485 #ifndef SERIALGC
1486 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1487 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1488 #endif // !SERIALGC
1490 JavaThread::JavaThread(bool is_attaching_via_jni) :
1491 Thread()
1492 #ifndef SERIALGC
1493 , _satb_mark_queue(&_satb_mark_queue_set),
1494 _dirty_card_queue(&_dirty_card_queue_set)
1495 #endif // !SERIALGC
1496 {
1497 initialize();
1498 if (is_attaching_via_jni) {
1499 _jni_attach_state = _attaching_via_jni;
1500 } else {
1501 _jni_attach_state = _not_attaching_via_jni;
1502 }
1503 assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor");
1504 _safepoint_visible = false;
1505 }
1507 bool JavaThread::reguard_stack(address cur_sp) {
1508 if (_stack_guard_state != stack_guard_yellow_disabled) {
1509 return true; // Stack already guarded or guard pages not needed.
1510 }
1512 if (register_stack_overflow()) {
1513 // For those architectures which have separate register and
1514 // memory stacks, we must check the register stack to see if
1515 // it has overflowed.
1516 return false;
1517 }
1519 // Java code never executes within the yellow zone: the latter is only
1520 // there to provoke an exception during stack banging. If java code
1521 // is executing there, either StackShadowPages should be larger, or
1522 // some exception code in c1, c2 or the interpreter isn't unwinding
1523 // when it should.
1524 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1526 enable_stack_yellow_zone();
1527 return true;
1528 }
1530 bool JavaThread::reguard_stack(void) {
1531 return reguard_stack(os::current_stack_pointer());
1532 }
1535 void JavaThread::block_if_vm_exited() {
1536 if (_terminated == _vm_exited) {
1537 // _vm_exited is set at safepoint, and Threads_lock is never released
1538 // we will block here forever
1539 Threads_lock->lock_without_safepoint_check();
1540 ShouldNotReachHere();
1541 }
1542 }
1545 // Remove this ifdef when C1 is ported to the compiler interface.
1546 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1548 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1549 Thread()
1550 #ifndef SERIALGC
1551 , _satb_mark_queue(&_satb_mark_queue_set),
1552 _dirty_card_queue(&_dirty_card_queue_set)
1553 #endif // !SERIALGC
1554 {
1555 if (TraceThreadEvents) {
1556 tty->print_cr("creating thread %p", this);
1557 }
1558 initialize();
1559 _jni_attach_state = _not_attaching_via_jni;
1560 set_entry_point(entry_point);
1561 // Create the native thread itself.
1562 // %note runtime_23
1563 os::ThreadType thr_type = os::java_thread;
1564 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1565 os::java_thread;
1566 os::create_thread(this, thr_type, stack_sz);
1567 _safepoint_visible = false;
1568 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1569 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1570 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1571 // the exception consists of creating the exception object & initializing it, initialization
1572 // will leave the VM via a JavaCall and then all locks must be unlocked).
1573 //
1574 // The thread is still suspended when we reach here. Thread must be explicit started
1575 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1576 // by calling Threads:add. The reason why this is not done here, is because the thread
1577 // object must be fully initialized (take a look at JVM_Start)
1578 }
1580 JavaThread::~JavaThread() {
1581 if (TraceThreadEvents) {
1582 tty->print_cr("terminate thread %p", this);
1583 }
1585 // By now, this thread should already be invisible to safepoint,
1586 // and its per-thread recorder also collected.
1587 assert(!is_safepoint_visible(), "wrong state");
1588 #if INCLUDE_NMT
1589 assert(get_recorder() == NULL, "Already collected");
1590 #endif // INCLUDE_NMT
1592 // JSR166 -- return the parker to the free list
1593 Parker::Release(_parker);
1594 _parker = NULL ;
1596 // Free any remaining previous UnrollBlock
1597 vframeArray* old_array = vframe_array_last();
1599 if (old_array != NULL) {
1600 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1601 old_array->set_unroll_block(NULL);
1602 delete old_info;
1603 delete old_array;
1604 }
1606 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1607 if (deferred != NULL) {
1608 // This can only happen if thread is destroyed before deoptimization occurs.
1609 assert(deferred->length() != 0, "empty array!");
1610 do {
1611 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1612 deferred->remove_at(0);
1613 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1614 delete dlv;
1615 } while (deferred->length() != 0);
1616 delete deferred;
1617 }
1619 // All Java related clean up happens in exit
1620 ThreadSafepointState::destroy(this);
1621 if (_thread_profiler != NULL) delete _thread_profiler;
1622 if (_thread_stat != NULL) delete _thread_stat;
1623 }
1626 // The first routine called by a new Java thread
1627 void JavaThread::run() {
1628 // initialize thread-local alloc buffer related fields
1629 this->initialize_tlab();
1631 // used to test validitity of stack trace backs
1632 this->record_base_of_stack_pointer();
1634 // Record real stack base and size.
1635 this->record_stack_base_and_size();
1637 // Initialize thread local storage; set before calling MutexLocker
1638 this->initialize_thread_local_storage();
1640 this->create_stack_guard_pages();
1642 this->cache_global_variables();
1644 // Thread is now sufficient initialized to be handled by the safepoint code as being
1645 // in the VM. Change thread state from _thread_new to _thread_in_vm
1646 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1648 assert(JavaThread::current() == this, "sanity check");
1649 assert(!Thread::current()->owns_locks(), "sanity check");
1651 DTRACE_THREAD_PROBE(start, this);
1653 // This operation might block. We call that after all safepoint checks for a new thread has
1654 // been completed.
1655 this->set_active_handles(JNIHandleBlock::allocate_block());
1657 if (JvmtiExport::should_post_thread_life()) {
1658 JvmtiExport::post_thread_start(this);
1659 }
1661 EVENT_BEGIN(TraceEventThreadStart, event);
1662 EVENT_COMMIT(event,
1663 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj())));
1665 // We call another function to do the rest so we are sure that the stack addresses used
1666 // from there will be lower than the stack base just computed
1667 thread_main_inner();
1669 // Note, thread is no longer valid at this point!
1670 }
1673 void JavaThread::thread_main_inner() {
1674 assert(JavaThread::current() == this, "sanity check");
1675 assert(this->threadObj() != NULL, "just checking");
1677 // Execute thread entry point unless this thread has a pending exception
1678 // or has been stopped before starting.
1679 // Note: Due to JVM_StopThread we can have pending exceptions already!
1680 if (!this->has_pending_exception() &&
1681 !java_lang_Thread::is_stillborn(this->threadObj())) {
1682 {
1683 ResourceMark rm(this);
1684 this->set_native_thread_name(this->get_thread_name());
1685 }
1686 HandleMark hm(this);
1687 this->entry_point()(this, this);
1688 }
1690 DTRACE_THREAD_PROBE(stop, this);
1692 this->exit(false);
1693 delete this;
1694 }
1697 static void ensure_join(JavaThread* thread) {
1698 // We do not need to grap the Threads_lock, since we are operating on ourself.
1699 Handle threadObj(thread, thread->threadObj());
1700 assert(threadObj.not_null(), "java thread object must exist");
1701 ObjectLocker lock(threadObj, thread);
1702 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1703 thread->clear_pending_exception();
1704 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1705 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1706 // Clear the native thread instance - this makes isAlive return false and allows the join()
1707 // to complete once we've done the notify_all below
1708 java_lang_Thread::set_thread(threadObj(), NULL);
1709 lock.notify_all(thread);
1710 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1711 thread->clear_pending_exception();
1712 }
1715 // For any new cleanup additions, please check to see if they need to be applied to
1716 // cleanup_failed_attach_current_thread as well.
1717 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1718 assert(this == JavaThread::current(), "thread consistency check");
1719 if (!InitializeJavaLangSystem) return;
1721 HandleMark hm(this);
1722 Handle uncaught_exception(this, this->pending_exception());
1723 this->clear_pending_exception();
1724 Handle threadObj(this, this->threadObj());
1725 assert(threadObj.not_null(), "Java thread object should be created");
1727 if (get_thread_profiler() != NULL) {
1728 get_thread_profiler()->disengage();
1729 ResourceMark rm;
1730 get_thread_profiler()->print(get_thread_name());
1731 }
1734 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1735 {
1736 EXCEPTION_MARK;
1738 CLEAR_PENDING_EXCEPTION;
1739 }
1740 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1741 // has to be fixed by a runtime query method
1742 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1743 // JSR-166: change call from from ThreadGroup.uncaughtException to
1744 // java.lang.Thread.dispatchUncaughtException
1745 if (uncaught_exception.not_null()) {
1746 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1747 {
1748 EXCEPTION_MARK;
1749 // Check if the method Thread.dispatchUncaughtException() exists. If so
1750 // call it. Otherwise we have an older library without the JSR-166 changes,
1751 // so call ThreadGroup.uncaughtException()
1752 KlassHandle recvrKlass(THREAD, threadObj->klass());
1753 CallInfo callinfo;
1754 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1755 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1756 vmSymbols::dispatchUncaughtException_name(),
1757 vmSymbols::throwable_void_signature(),
1758 KlassHandle(), false, false, THREAD);
1759 CLEAR_PENDING_EXCEPTION;
1760 methodHandle method = callinfo.selected_method();
1761 if (method.not_null()) {
1762 JavaValue result(T_VOID);
1763 JavaCalls::call_virtual(&result,
1764 threadObj, thread_klass,
1765 vmSymbols::dispatchUncaughtException_name(),
1766 vmSymbols::throwable_void_signature(),
1767 uncaught_exception,
1768 THREAD);
1769 } else {
1770 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1771 JavaValue result(T_VOID);
1772 JavaCalls::call_virtual(&result,
1773 group, thread_group,
1774 vmSymbols::uncaughtException_name(),
1775 vmSymbols::thread_throwable_void_signature(),
1776 threadObj, // Arg 1
1777 uncaught_exception, // Arg 2
1778 THREAD);
1779 }
1780 if (HAS_PENDING_EXCEPTION) {
1781 ResourceMark rm(this);
1782 jio_fprintf(defaultStream::error_stream(),
1783 "\nException: %s thrown from the UncaughtExceptionHandler"
1784 " in thread \"%s\"\n",
1785 pending_exception()->klass()->external_name(),
1786 get_thread_name());
1787 CLEAR_PENDING_EXCEPTION;
1788 }
1789 }
1790 }
1792 // Called before the java thread exit since we want to read info
1793 // from java_lang_Thread object
1794 EVENT_BEGIN(TraceEventThreadEnd, event);
1795 EVENT_COMMIT(event,
1796 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj())));
1798 // Call after last event on thread
1799 EVENT_THREAD_EXIT(this);
1801 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1802 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1803 // is deprecated anyhow.
1804 { int count = 3;
1805 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1806 EXCEPTION_MARK;
1807 JavaValue result(T_VOID);
1808 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1809 JavaCalls::call_virtual(&result,
1810 threadObj, thread_klass,
1811 vmSymbols::exit_method_name(),
1812 vmSymbols::void_method_signature(),
1813 THREAD);
1814 CLEAR_PENDING_EXCEPTION;
1815 }
1816 }
1818 // notify JVMTI
1819 if (JvmtiExport::should_post_thread_life()) {
1820 JvmtiExport::post_thread_end(this);
1821 }
1823 // We have notified the agents that we are exiting, before we go on,
1824 // we must check for a pending external suspend request and honor it
1825 // in order to not surprise the thread that made the suspend request.
1826 while (true) {
1827 {
1828 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1829 if (!is_external_suspend()) {
1830 set_terminated(_thread_exiting);
1831 ThreadService::current_thread_exiting(this);
1832 break;
1833 }
1834 // Implied else:
1835 // Things get a little tricky here. We have a pending external
1836 // suspend request, but we are holding the SR_lock so we
1837 // can't just self-suspend. So we temporarily drop the lock
1838 // and then self-suspend.
1839 }
1841 ThreadBlockInVM tbivm(this);
1842 java_suspend_self();
1844 // We're done with this suspend request, but we have to loop around
1845 // and check again. Eventually we will get SR_lock without a pending
1846 // external suspend request and will be able to mark ourselves as
1847 // exiting.
1848 }
1849 // no more external suspends are allowed at this point
1850 } else {
1851 // before_exit() has already posted JVMTI THREAD_END events
1852 }
1854 // Notify waiters on thread object. This has to be done after exit() is called
1855 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1856 // group should have the destroyed bit set before waiters are notified).
1857 ensure_join(this);
1858 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1860 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1861 // held by this thread must be released. A detach operation must only
1862 // get here if there are no Java frames on the stack. Therefore, any
1863 // owned monitors at this point MUST be JNI-acquired monitors which are
1864 // pre-inflated and in the monitor cache.
1865 //
1866 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1867 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1868 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1869 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1870 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1871 }
1873 // These things needs to be done while we are still a Java Thread. Make sure that thread
1874 // is in a consistent state, in case GC happens
1875 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1877 if (active_handles() != NULL) {
1878 JNIHandleBlock* block = active_handles();
1879 set_active_handles(NULL);
1880 JNIHandleBlock::release_block(block);
1881 }
1883 if (free_handle_block() != NULL) {
1884 JNIHandleBlock* block = free_handle_block();
1885 set_free_handle_block(NULL);
1886 JNIHandleBlock::release_block(block);
1887 }
1889 // These have to be removed while this is still a valid thread.
1890 remove_stack_guard_pages();
1892 if (UseTLAB) {
1893 tlab().make_parsable(true); // retire TLAB
1894 }
1896 if (JvmtiEnv::environments_might_exist()) {
1897 JvmtiExport::cleanup_thread(this);
1898 }
1900 #ifndef SERIALGC
1901 // We must flush G1-related buffers before removing a thread from
1902 // the list of active threads.
1903 if (UseG1GC) {
1904 flush_barrier_queues();
1905 }
1906 #endif
1908 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1909 Threads::remove(this);
1910 }
1912 #ifndef SERIALGC
1913 // Flush G1-related queues.
1914 void JavaThread::flush_barrier_queues() {
1915 satb_mark_queue().flush();
1916 dirty_card_queue().flush();
1917 }
1919 void JavaThread::initialize_queues() {
1920 assert(!SafepointSynchronize::is_at_safepoint(),
1921 "we should not be at a safepoint");
1923 ObjPtrQueue& satb_queue = satb_mark_queue();
1924 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1925 // The SATB queue should have been constructed with its active
1926 // field set to false.
1927 assert(!satb_queue.is_active(), "SATB queue should not be active");
1928 assert(satb_queue.is_empty(), "SATB queue should be empty");
1929 // If we are creating the thread during a marking cycle, we should
1930 // set the active field of the SATB queue to true.
1931 if (satb_queue_set.is_active()) {
1932 satb_queue.set_active(true);
1933 }
1935 DirtyCardQueue& dirty_queue = dirty_card_queue();
1936 // The dirty card queue should have been constructed with its
1937 // active field set to true.
1938 assert(dirty_queue.is_active(), "dirty card queue should be active");
1939 }
1940 #endif // !SERIALGC
1942 void JavaThread::cleanup_failed_attach_current_thread() {
1943 if (get_thread_profiler() != NULL) {
1944 get_thread_profiler()->disengage();
1945 ResourceMark rm;
1946 get_thread_profiler()->print(get_thread_name());
1947 }
1949 if (active_handles() != NULL) {
1950 JNIHandleBlock* block = active_handles();
1951 set_active_handles(NULL);
1952 JNIHandleBlock::release_block(block);
1953 }
1955 if (free_handle_block() != NULL) {
1956 JNIHandleBlock* block = free_handle_block();
1957 set_free_handle_block(NULL);
1958 JNIHandleBlock::release_block(block);
1959 }
1961 // These have to be removed while this is still a valid thread.
1962 remove_stack_guard_pages();
1964 if (UseTLAB) {
1965 tlab().make_parsable(true); // retire TLAB, if any
1966 }
1968 #ifndef SERIALGC
1969 if (UseG1GC) {
1970 flush_barrier_queues();
1971 }
1972 #endif
1974 Threads::remove(this);
1975 delete this;
1976 }
1981 JavaThread* JavaThread::active() {
1982 Thread* thread = ThreadLocalStorage::thread();
1983 assert(thread != NULL, "just checking");
1984 if (thread->is_Java_thread()) {
1985 return (JavaThread*) thread;
1986 } else {
1987 assert(thread->is_VM_thread(), "this must be a vm thread");
1988 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1989 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1990 assert(ret->is_Java_thread(), "must be a Java thread");
1991 return ret;
1992 }
1993 }
1995 bool JavaThread::is_lock_owned(address adr) const {
1996 if (Thread::is_lock_owned(adr)) return true;
1998 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1999 if (chunk->contains(adr)) return true;
2000 }
2002 return false;
2003 }
2006 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2007 chunk->set_next(monitor_chunks());
2008 set_monitor_chunks(chunk);
2009 }
2011 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2012 guarantee(monitor_chunks() != NULL, "must be non empty");
2013 if (monitor_chunks() == chunk) {
2014 set_monitor_chunks(chunk->next());
2015 } else {
2016 MonitorChunk* prev = monitor_chunks();
2017 while (prev->next() != chunk) prev = prev->next();
2018 prev->set_next(chunk->next());
2019 }
2020 }
2022 // JVM support.
2024 // Note: this function shouldn't block if it's called in
2025 // _thread_in_native_trans state (such as from
2026 // check_special_condition_for_native_trans()).
2027 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2029 if (has_last_Java_frame() && has_async_condition()) {
2030 // If we are at a polling page safepoint (not a poll return)
2031 // then we must defer async exception because live registers
2032 // will be clobbered by the exception path. Poll return is
2033 // ok because the call we a returning from already collides
2034 // with exception handling registers and so there is no issue.
2035 // (The exception handling path kills call result registers but
2036 // this is ok since the exception kills the result anyway).
2038 if (is_at_poll_safepoint()) {
2039 // if the code we are returning to has deoptimized we must defer
2040 // the exception otherwise live registers get clobbered on the
2041 // exception path before deoptimization is able to retrieve them.
2042 //
2043 RegisterMap map(this, false);
2044 frame caller_fr = last_frame().sender(&map);
2045 assert(caller_fr.is_compiled_frame(), "what?");
2046 if (caller_fr.is_deoptimized_frame()) {
2047 if (TraceExceptions) {
2048 ResourceMark rm;
2049 tty->print_cr("deferred async exception at compiled safepoint");
2050 }
2051 return;
2052 }
2053 }
2054 }
2056 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2057 if (condition == _no_async_condition) {
2058 // Conditions have changed since has_special_runtime_exit_condition()
2059 // was called:
2060 // - if we were here only because of an external suspend request,
2061 // then that was taken care of above (or cancelled) so we are done
2062 // - if we were here because of another async request, then it has
2063 // been cleared between the has_special_runtime_exit_condition()
2064 // and now so again we are done
2065 return;
2066 }
2068 // Check for pending async. exception
2069 if (_pending_async_exception != NULL) {
2070 // Only overwrite an already pending exception, if it is not a threadDeath.
2071 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2073 // We cannot call Exceptions::_throw(...) here because we cannot block
2074 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2076 if (TraceExceptions) {
2077 ResourceMark rm;
2078 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2079 if (has_last_Java_frame() ) {
2080 frame f = last_frame();
2081 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2082 }
2083 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2084 }
2085 _pending_async_exception = NULL;
2086 clear_has_async_exception();
2087 }
2088 }
2090 if (check_unsafe_error &&
2091 condition == _async_unsafe_access_error && !has_pending_exception()) {
2092 condition = _no_async_condition; // done
2093 switch (thread_state()) {
2094 case _thread_in_vm:
2095 {
2096 JavaThread* THREAD = this;
2097 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2098 }
2099 case _thread_in_native:
2100 {
2101 ThreadInVMfromNative tiv(this);
2102 JavaThread* THREAD = this;
2103 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2104 }
2105 case _thread_in_Java:
2106 {
2107 ThreadInVMfromJava tiv(this);
2108 JavaThread* THREAD = this;
2109 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2110 }
2111 default:
2112 ShouldNotReachHere();
2113 }
2114 }
2116 assert(condition == _no_async_condition || has_pending_exception() ||
2117 (!check_unsafe_error && condition == _async_unsafe_access_error),
2118 "must have handled the async condition, if no exception");
2119 }
2121 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2122 //
2123 // Check for pending external suspend. Internal suspend requests do
2124 // not use handle_special_runtime_exit_condition().
2125 // If JNIEnv proxies are allowed, don't self-suspend if the target
2126 // thread is not the current thread. In older versions of jdbx, jdbx
2127 // threads could call into the VM with another thread's JNIEnv so we
2128 // can be here operating on behalf of a suspended thread (4432884).
2129 bool do_self_suspend = is_external_suspend_with_lock();
2130 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2131 //
2132 // Because thread is external suspended the safepoint code will count
2133 // thread as at a safepoint. This can be odd because we can be here
2134 // as _thread_in_Java which would normally transition to _thread_blocked
2135 // at a safepoint. We would like to mark the thread as _thread_blocked
2136 // before calling java_suspend_self like all other callers of it but
2137 // we must then observe proper safepoint protocol. (We can't leave
2138 // _thread_blocked with a safepoint in progress). However we can be
2139 // here as _thread_in_native_trans so we can't use a normal transition
2140 // constructor/destructor pair because they assert on that type of
2141 // transition. We could do something like:
2142 //
2143 // JavaThreadState state = thread_state();
2144 // set_thread_state(_thread_in_vm);
2145 // {
2146 // ThreadBlockInVM tbivm(this);
2147 // java_suspend_self()
2148 // }
2149 // set_thread_state(_thread_in_vm_trans);
2150 // if (safepoint) block;
2151 // set_thread_state(state);
2152 //
2153 // but that is pretty messy. Instead we just go with the way the
2154 // code has worked before and note that this is the only path to
2155 // java_suspend_self that doesn't put the thread in _thread_blocked
2156 // mode.
2158 frame_anchor()->make_walkable(this);
2159 java_suspend_self();
2161 // We might be here for reasons in addition to the self-suspend request
2162 // so check for other async requests.
2163 }
2165 if (check_asyncs) {
2166 check_and_handle_async_exceptions();
2167 }
2168 }
2170 void JavaThread::send_thread_stop(oop java_throwable) {
2171 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2172 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2173 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2175 // Do not throw asynchronous exceptions against the compiler thread
2176 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2177 if (is_Compiler_thread()) return;
2179 {
2180 // Actually throw the Throwable against the target Thread - however
2181 // only if there is no thread death exception installed already.
2182 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2183 // If the topmost frame is a runtime stub, then we are calling into
2184 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2185 // must deoptimize the caller before continuing, as the compiled exception handler table
2186 // may not be valid
2187 if (has_last_Java_frame()) {
2188 frame f = last_frame();
2189 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2190 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2191 RegisterMap reg_map(this, UseBiasedLocking);
2192 frame compiled_frame = f.sender(®_map);
2193 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2194 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2195 }
2196 }
2197 }
2199 // Set async. pending exception in thread.
2200 set_pending_async_exception(java_throwable);
2202 if (TraceExceptions) {
2203 ResourceMark rm;
2204 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2205 }
2206 // for AbortVMOnException flag
2207 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2208 }
2209 }
2212 // Interrupt thread so it will wake up from a potential wait()
2213 Thread::interrupt(this);
2214 }
2216 // External suspension mechanism.
2217 //
2218 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2219 // to any VM_locks and it is at a transition
2220 // Self-suspension will happen on the transition out of the vm.
2221 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2222 //
2223 // Guarantees on return:
2224 // + Target thread will not execute any new bytecode (that's why we need to
2225 // force a safepoint)
2226 // + Target thread will not enter any new monitors
2227 //
2228 void JavaThread::java_suspend() {
2229 { MutexLocker mu(Threads_lock);
2230 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2231 return;
2232 }
2233 }
2235 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2236 if (!is_external_suspend()) {
2237 // a racing resume has cancelled us; bail out now
2238 return;
2239 }
2241 // suspend is done
2242 uint32_t debug_bits = 0;
2243 // Warning: is_ext_suspend_completed() may temporarily drop the
2244 // SR_lock to allow the thread to reach a stable thread state if
2245 // it is currently in a transient thread state.
2246 if (is_ext_suspend_completed(false /* !called_by_wait */,
2247 SuspendRetryDelay, &debug_bits) ) {
2248 return;
2249 }
2250 }
2252 VM_ForceSafepoint vm_suspend;
2253 VMThread::execute(&vm_suspend);
2254 }
2256 // Part II of external suspension.
2257 // A JavaThread self suspends when it detects a pending external suspend
2258 // request. This is usually on transitions. It is also done in places
2259 // where continuing to the next transition would surprise the caller,
2260 // e.g., monitor entry.
2261 //
2262 // Returns the number of times that the thread self-suspended.
2263 //
2264 // Note: DO NOT call java_suspend_self() when you just want to block current
2265 // thread. java_suspend_self() is the second stage of cooperative
2266 // suspension for external suspend requests and should only be used
2267 // to complete an external suspend request.
2268 //
2269 int JavaThread::java_suspend_self() {
2270 int ret = 0;
2272 // we are in the process of exiting so don't suspend
2273 if (is_exiting()) {
2274 clear_external_suspend();
2275 return ret;
2276 }
2278 assert(_anchor.walkable() ||
2279 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2280 "must have walkable stack");
2282 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2284 assert(!this->is_ext_suspended(),
2285 "a thread trying to self-suspend should not already be suspended");
2287 if (this->is_suspend_equivalent()) {
2288 // If we are self-suspending as a result of the lifting of a
2289 // suspend equivalent condition, then the suspend_equivalent
2290 // flag is not cleared until we set the ext_suspended flag so
2291 // that wait_for_ext_suspend_completion() returns consistent
2292 // results.
2293 this->clear_suspend_equivalent();
2294 }
2296 // A racing resume may have cancelled us before we grabbed SR_lock
2297 // above. Or another external suspend request could be waiting for us
2298 // by the time we return from SR_lock()->wait(). The thread
2299 // that requested the suspension may already be trying to walk our
2300 // stack and if we return now, we can change the stack out from under
2301 // it. This would be a "bad thing (TM)" and cause the stack walker
2302 // to crash. We stay self-suspended until there are no more pending
2303 // external suspend requests.
2304 while (is_external_suspend()) {
2305 ret++;
2306 this->set_ext_suspended();
2308 // _ext_suspended flag is cleared by java_resume()
2309 while (is_ext_suspended()) {
2310 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2311 }
2312 }
2314 return ret;
2315 }
2317 #ifdef ASSERT
2318 // verify the JavaThread has not yet been published in the Threads::list, and
2319 // hence doesn't need protection from concurrent access at this stage
2320 void JavaThread::verify_not_published() {
2321 if (!Threads_lock->owned_by_self()) {
2322 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2323 assert( !Threads::includes(this),
2324 "java thread shouldn't have been published yet!");
2325 }
2326 else {
2327 assert( !Threads::includes(this),
2328 "java thread shouldn't have been published yet!");
2329 }
2330 }
2331 #endif
2333 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2334 // progress or when _suspend_flags is non-zero.
2335 // Current thread needs to self-suspend if there is a suspend request and/or
2336 // block if a safepoint is in progress.
2337 // Async exception ISN'T checked.
2338 // Note only the ThreadInVMfromNative transition can call this function
2339 // directly and when thread state is _thread_in_native_trans
2340 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2341 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2343 JavaThread *curJT = JavaThread::current();
2344 bool do_self_suspend = thread->is_external_suspend();
2346 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2348 // If JNIEnv proxies are allowed, don't self-suspend if the target
2349 // thread is not the current thread. In older versions of jdbx, jdbx
2350 // threads could call into the VM with another thread's JNIEnv so we
2351 // can be here operating on behalf of a suspended thread (4432884).
2352 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2353 JavaThreadState state = thread->thread_state();
2355 // We mark this thread_blocked state as a suspend-equivalent so
2356 // that a caller to is_ext_suspend_completed() won't be confused.
2357 // The suspend-equivalent state is cleared by java_suspend_self().
2358 thread->set_suspend_equivalent();
2360 // If the safepoint code sees the _thread_in_native_trans state, it will
2361 // wait until the thread changes to other thread state. There is no
2362 // guarantee on how soon we can obtain the SR_lock and complete the
2363 // self-suspend request. It would be a bad idea to let safepoint wait for
2364 // too long. Temporarily change the state to _thread_blocked to
2365 // let the VM thread know that this thread is ready for GC. The problem
2366 // of changing thread state is that safepoint could happen just after
2367 // java_suspend_self() returns after being resumed, and VM thread will
2368 // see the _thread_blocked state. We must check for safepoint
2369 // after restoring the state and make sure we won't leave while a safepoint
2370 // is in progress.
2371 thread->set_thread_state(_thread_blocked);
2372 thread->java_suspend_self();
2373 thread->set_thread_state(state);
2374 // Make sure new state is seen by VM thread
2375 if (os::is_MP()) {
2376 if (UseMembar) {
2377 // Force a fence between the write above and read below
2378 OrderAccess::fence();
2379 } else {
2380 // Must use this rather than serialization page in particular on Windows
2381 InterfaceSupport::serialize_memory(thread);
2382 }
2383 }
2384 }
2386 if (SafepointSynchronize::do_call_back()) {
2387 // If we are safepointing, then block the caller which may not be
2388 // the same as the target thread (see above).
2389 SafepointSynchronize::block(curJT);
2390 }
2392 if (thread->is_deopt_suspend()) {
2393 thread->clear_deopt_suspend();
2394 RegisterMap map(thread, false);
2395 frame f = thread->last_frame();
2396 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2397 f = f.sender(&map);
2398 }
2399 if (f.id() == thread->must_deopt_id()) {
2400 thread->clear_must_deopt_id();
2401 f.deoptimize(thread);
2402 } else {
2403 fatal("missed deoptimization!");
2404 }
2405 }
2406 }
2408 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2409 // progress or when _suspend_flags is non-zero.
2410 // Current thread needs to self-suspend if there is a suspend request and/or
2411 // block if a safepoint is in progress.
2412 // Also check for pending async exception (not including unsafe access error).
2413 // Note only the native==>VM/Java barriers can call this function and when
2414 // thread state is _thread_in_native_trans.
2415 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2416 check_safepoint_and_suspend_for_native_trans(thread);
2418 if (thread->has_async_exception()) {
2419 // We are in _thread_in_native_trans state, don't handle unsafe
2420 // access error since that may block.
2421 thread->check_and_handle_async_exceptions(false);
2422 }
2423 }
2425 // This is a variant of the normal
2426 // check_special_condition_for_native_trans with slightly different
2427 // semantics for use by critical native wrappers. It does all the
2428 // normal checks but also performs the transition back into
2429 // thread_in_Java state. This is required so that critical natives
2430 // can potentially block and perform a GC if they are the last thread
2431 // exiting the GC_locker.
2432 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2433 check_special_condition_for_native_trans(thread);
2435 // Finish the transition
2436 thread->set_thread_state(_thread_in_Java);
2438 if (thread->do_critical_native_unlock()) {
2439 ThreadInVMfromJavaNoAsyncException tiv(thread);
2440 GC_locker::unlock_critical(thread);
2441 thread->clear_critical_native_unlock();
2442 }
2443 }
2445 // We need to guarantee the Threads_lock here, since resumes are not
2446 // allowed during safepoint synchronization
2447 // Can only resume from an external suspension
2448 void JavaThread::java_resume() {
2449 assert_locked_or_safepoint(Threads_lock);
2451 // Sanity check: thread is gone, has started exiting or the thread
2452 // was not externally suspended.
2453 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2454 return;
2455 }
2457 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2459 clear_external_suspend();
2461 if (is_ext_suspended()) {
2462 clear_ext_suspended();
2463 SR_lock()->notify_all();
2464 }
2465 }
2467 void JavaThread::create_stack_guard_pages() {
2468 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2469 address low_addr = stack_base() - stack_size();
2470 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2472 int allocate = os::allocate_stack_guard_pages();
2473 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2475 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2476 warning("Attempt to allocate stack guard pages failed.");
2477 return;
2478 }
2480 if (os::guard_memory((char *) low_addr, len)) {
2481 _stack_guard_state = stack_guard_enabled;
2482 } else {
2483 warning("Attempt to protect stack guard pages failed.");
2484 if (os::uncommit_memory((char *) low_addr, len)) {
2485 warning("Attempt to deallocate stack guard pages failed.");
2486 }
2487 }
2488 }
2490 void JavaThread::remove_stack_guard_pages() {
2491 assert(Thread::current() == this, "from different thread");
2492 if (_stack_guard_state == stack_guard_unused) return;
2493 address low_addr = stack_base() - stack_size();
2494 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2496 if (os::allocate_stack_guard_pages()) {
2497 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2498 _stack_guard_state = stack_guard_unused;
2499 } else {
2500 warning("Attempt to deallocate stack guard pages failed.");
2501 }
2502 } else {
2503 if (_stack_guard_state == stack_guard_unused) return;
2504 if (os::unguard_memory((char *) low_addr, len)) {
2505 _stack_guard_state = stack_guard_unused;
2506 } else {
2507 warning("Attempt to unprotect stack guard pages failed.");
2508 }
2509 }
2510 }
2512 void JavaThread::enable_stack_yellow_zone() {
2513 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2514 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2516 // The base notation is from the stacks point of view, growing downward.
2517 // We need to adjust it to work correctly with guard_memory()
2518 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2520 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2521 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2523 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2524 _stack_guard_state = stack_guard_enabled;
2525 } else {
2526 warning("Attempt to guard stack yellow zone failed.");
2527 }
2528 enable_register_stack_guard();
2529 }
2531 void JavaThread::disable_stack_yellow_zone() {
2532 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2533 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2535 // Simply return if called for a thread that does not use guard pages.
2536 if (_stack_guard_state == stack_guard_unused) return;
2538 // The base notation is from the stacks point of view, growing downward.
2539 // We need to adjust it to work correctly with guard_memory()
2540 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2542 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2543 _stack_guard_state = stack_guard_yellow_disabled;
2544 } else {
2545 warning("Attempt to unguard stack yellow zone failed.");
2546 }
2547 disable_register_stack_guard();
2548 }
2550 void JavaThread::enable_stack_red_zone() {
2551 // The base notation is from the stacks point of view, growing downward.
2552 // We need to adjust it to work correctly with guard_memory()
2553 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2554 address base = stack_red_zone_base() - stack_red_zone_size();
2556 guarantee(base < stack_base(),"Error calculating stack red zone");
2557 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2559 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2560 warning("Attempt to guard stack red zone failed.");
2561 }
2562 }
2564 void JavaThread::disable_stack_red_zone() {
2565 // The base notation is from the stacks point of view, growing downward.
2566 // We need to adjust it to work correctly with guard_memory()
2567 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2568 address base = stack_red_zone_base() - stack_red_zone_size();
2569 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2570 warning("Attempt to unguard stack red zone failed.");
2571 }
2572 }
2574 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2575 // ignore is there is no stack
2576 if (!has_last_Java_frame()) return;
2577 // traverse the stack frames. Starts from top frame.
2578 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2579 frame* fr = fst.current();
2580 f(fr, fst.register_map());
2581 }
2582 }
2585 #ifndef PRODUCT
2586 // Deoptimization
2587 // Function for testing deoptimization
2588 void JavaThread::deoptimize() {
2589 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2590 StackFrameStream fst(this, UseBiasedLocking);
2591 bool deopt = false; // Dump stack only if a deopt actually happens.
2592 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2593 // Iterate over all frames in the thread and deoptimize
2594 for(; !fst.is_done(); fst.next()) {
2595 if(fst.current()->can_be_deoptimized()) {
2597 if (only_at) {
2598 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2599 // consists of comma or carriage return separated numbers so
2600 // search for the current bci in that string.
2601 address pc = fst.current()->pc();
2602 nmethod* nm = (nmethod*) fst.current()->cb();
2603 ScopeDesc* sd = nm->scope_desc_at( pc);
2604 char buffer[8];
2605 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2606 size_t len = strlen(buffer);
2607 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2608 while (found != NULL) {
2609 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2610 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2611 // Check that the bci found is bracketed by terminators.
2612 break;
2613 }
2614 found = strstr(found + 1, buffer);
2615 }
2616 if (!found) {
2617 continue;
2618 }
2619 }
2621 if (DebugDeoptimization && !deopt) {
2622 deopt = true; // One-time only print before deopt
2623 tty->print_cr("[BEFORE Deoptimization]");
2624 trace_frames();
2625 trace_stack();
2626 }
2627 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2628 }
2629 }
2631 if (DebugDeoptimization && deopt) {
2632 tty->print_cr("[AFTER Deoptimization]");
2633 trace_frames();
2634 }
2635 }
2638 // Make zombies
2639 void JavaThread::make_zombies() {
2640 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2641 if (fst.current()->can_be_deoptimized()) {
2642 // it is a Java nmethod
2643 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2644 nm->make_not_entrant();
2645 }
2646 }
2647 }
2648 #endif // PRODUCT
2651 void JavaThread::deoptimized_wrt_marked_nmethods() {
2652 if (!has_last_Java_frame()) return;
2653 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2654 StackFrameStream fst(this, UseBiasedLocking);
2655 for(; !fst.is_done(); fst.next()) {
2656 if (fst.current()->should_be_deoptimized()) {
2657 if (LogCompilation && xtty != NULL) {
2658 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2659 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2660 this->name(), nm != NULL ? nm->compile_id() : -1);
2661 }
2663 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2664 }
2665 }
2666 }
2669 // GC support
2670 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2672 void JavaThread::gc_epilogue() {
2673 frames_do(frame_gc_epilogue);
2674 }
2677 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2679 void JavaThread::gc_prologue() {
2680 frames_do(frame_gc_prologue);
2681 }
2683 // If the caller is a NamedThread, then remember, in the current scope,
2684 // the given JavaThread in its _processed_thread field.
2685 class RememberProcessedThread: public StackObj {
2686 NamedThread* _cur_thr;
2687 public:
2688 RememberProcessedThread(JavaThread* jthr) {
2689 Thread* thread = Thread::current();
2690 if (thread->is_Named_thread()) {
2691 _cur_thr = (NamedThread *)thread;
2692 _cur_thr->set_processed_thread(jthr);
2693 } else {
2694 _cur_thr = NULL;
2695 }
2696 }
2698 ~RememberProcessedThread() {
2699 if (_cur_thr) {
2700 _cur_thr->set_processed_thread(NULL);
2701 }
2702 }
2703 };
2705 void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
2706 // Verify that the deferred card marks have been flushed.
2707 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2709 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2710 // since there may be more than one thread using each ThreadProfiler.
2712 // Traverse the GCHandles
2713 Thread::oops_do(f, cld_f, cf);
2715 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2716 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2718 if (has_last_Java_frame()) {
2719 // Record JavaThread to GC thread
2720 RememberProcessedThread rpt(this);
2722 // Traverse the privileged stack
2723 if (_privileged_stack_top != NULL) {
2724 _privileged_stack_top->oops_do(f);
2725 }
2727 // traverse the registered growable array
2728 if (_array_for_gc != NULL) {
2729 for (int index = 0; index < _array_for_gc->length(); index++) {
2730 f->do_oop(_array_for_gc->adr_at(index));
2731 }
2732 }
2734 // Traverse the monitor chunks
2735 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2736 chunk->oops_do(f);
2737 }
2739 // Traverse the execution stack
2740 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2741 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2742 }
2743 }
2745 // callee_target is never live across a gc point so NULL it here should
2746 // it still contain a methdOop.
2748 set_callee_target(NULL);
2750 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2751 // If we have deferred set_locals there might be oops waiting to be
2752 // written
2753 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2754 if (list != NULL) {
2755 for (int i = 0; i < list->length(); i++) {
2756 list->at(i)->oops_do(f);
2757 }
2758 }
2760 // Traverse instance variables at the end since the GC may be moving things
2761 // around using this function
2762 f->do_oop((oop*) &_threadObj);
2763 f->do_oop((oop*) &_vm_result);
2764 f->do_oop((oop*) &_exception_oop);
2765 f->do_oop((oop*) &_pending_async_exception);
2767 if (jvmti_thread_state() != NULL) {
2768 jvmti_thread_state()->oops_do(f);
2769 }
2770 }
2772 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2773 Thread::nmethods_do(cf); // (super method is a no-op)
2775 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2776 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2778 if (has_last_Java_frame()) {
2779 // Traverse the execution stack
2780 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2781 fst.current()->nmethods_do(cf);
2782 }
2783 }
2784 }
2786 void JavaThread::metadata_do(void f(Metadata*)) {
2787 Thread::metadata_do(f);
2788 if (has_last_Java_frame()) {
2789 // Traverse the execution stack to call f() on the methods in the stack
2790 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2791 fst.current()->metadata_do(f);
2792 }
2793 } else if (is_Compiler_thread()) {
2794 // need to walk ciMetadata in current compile tasks to keep alive.
2795 CompilerThread* ct = (CompilerThread*)this;
2796 if (ct->env() != NULL) {
2797 ct->env()->metadata_do(f);
2798 }
2799 }
2800 }
2802 // Printing
2803 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2804 switch (_thread_state) {
2805 case _thread_uninitialized: return "_thread_uninitialized";
2806 case _thread_new: return "_thread_new";
2807 case _thread_new_trans: return "_thread_new_trans";
2808 case _thread_in_native: return "_thread_in_native";
2809 case _thread_in_native_trans: return "_thread_in_native_trans";
2810 case _thread_in_vm: return "_thread_in_vm";
2811 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2812 case _thread_in_Java: return "_thread_in_Java";
2813 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2814 case _thread_blocked: return "_thread_blocked";
2815 case _thread_blocked_trans: return "_thread_blocked_trans";
2816 default: return "unknown thread state";
2817 }
2818 }
2820 #ifndef PRODUCT
2821 void JavaThread::print_thread_state_on(outputStream *st) const {
2822 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2823 };
2824 void JavaThread::print_thread_state() const {
2825 print_thread_state_on(tty);
2826 };
2827 #endif // PRODUCT
2829 // Called by Threads::print() for VM_PrintThreads operation
2830 void JavaThread::print_on(outputStream *st) const {
2831 st->print("\"%s\" ", get_thread_name());
2832 oop thread_oop = threadObj();
2833 if (thread_oop != NULL) {
2834 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2835 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2836 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2837 }
2838 Thread::print_on(st);
2839 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2840 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2841 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2842 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2843 }
2844 #ifndef PRODUCT
2845 print_thread_state_on(st);
2846 _safepoint_state->print_on(st);
2847 #endif // PRODUCT
2848 }
2850 // Called by fatal error handler. The difference between this and
2851 // JavaThread::print() is that we can't grab lock or allocate memory.
2852 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2853 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2854 oop thread_obj = threadObj();
2855 if (thread_obj != NULL) {
2856 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2857 }
2858 st->print(" [");
2859 st->print("%s", _get_thread_state_name(_thread_state));
2860 if (osthread()) {
2861 st->print(", id=%d", osthread()->thread_id());
2862 }
2863 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2864 _stack_base - _stack_size, _stack_base);
2865 st->print("]");
2866 return;
2867 }
2869 // Verification
2871 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2873 void JavaThread::verify() {
2874 // Verify oops in the thread.
2875 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2877 // Verify the stack frames.
2878 frames_do(frame_verify);
2879 }
2881 // CR 6300358 (sub-CR 2137150)
2882 // Most callers of this method assume that it can't return NULL but a
2883 // thread may not have a name whilst it is in the process of attaching to
2884 // the VM - see CR 6412693, and there are places where a JavaThread can be
2885 // seen prior to having it's threadObj set (eg JNI attaching threads and
2886 // if vm exit occurs during initialization). These cases can all be accounted
2887 // for such that this method never returns NULL.
2888 const char* JavaThread::get_thread_name() const {
2889 #ifdef ASSERT
2890 // early safepoints can hit while current thread does not yet have TLS
2891 if (!SafepointSynchronize::is_at_safepoint()) {
2892 Thread *cur = Thread::current();
2893 if (!(cur->is_Java_thread() && cur == this)) {
2894 // Current JavaThreads are allowed to get their own name without
2895 // the Threads_lock.
2896 assert_locked_or_safepoint(Threads_lock);
2897 }
2898 }
2899 #endif // ASSERT
2900 return get_thread_name_string();
2901 }
2903 // Returns a non-NULL representation of this thread's name, or a suitable
2904 // descriptive string if there is no set name
2905 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2906 const char* name_str;
2907 oop thread_obj = threadObj();
2908 if (thread_obj != NULL) {
2909 typeArrayOop name = java_lang_Thread::name(thread_obj);
2910 if (name != NULL) {
2911 if (buf == NULL) {
2912 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2913 }
2914 else {
2915 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2916 }
2917 }
2918 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2919 name_str = "<no-name - thread is attaching>";
2920 }
2921 else {
2922 name_str = Thread::name();
2923 }
2924 }
2925 else {
2926 name_str = Thread::name();
2927 }
2928 assert(name_str != NULL, "unexpected NULL thread name");
2929 return name_str;
2930 }
2933 const char* JavaThread::get_threadgroup_name() const {
2934 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2935 oop thread_obj = threadObj();
2936 if (thread_obj != NULL) {
2937 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2938 if (thread_group != NULL) {
2939 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2940 // ThreadGroup.name can be null
2941 if (name != NULL) {
2942 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2943 return str;
2944 }
2945 }
2946 }
2947 return NULL;
2948 }
2950 const char* JavaThread::get_parent_name() const {
2951 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2952 oop thread_obj = threadObj();
2953 if (thread_obj != NULL) {
2954 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2955 if (thread_group != NULL) {
2956 oop parent = java_lang_ThreadGroup::parent(thread_group);
2957 if (parent != NULL) {
2958 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2959 // ThreadGroup.name can be null
2960 if (name != NULL) {
2961 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2962 return str;
2963 }
2964 }
2965 }
2966 }
2967 return NULL;
2968 }
2970 ThreadPriority JavaThread::java_priority() const {
2971 oop thr_oop = threadObj();
2972 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2973 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2974 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2975 return priority;
2976 }
2978 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2980 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2981 // Link Java Thread object <-> C++ Thread
2983 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2984 // and put it into a new Handle. The Handle "thread_oop" can then
2985 // be used to pass the C++ thread object to other methods.
2987 // Set the Java level thread object (jthread) field of the
2988 // new thread (a JavaThread *) to C++ thread object using the
2989 // "thread_oop" handle.
2991 // Set the thread field (a JavaThread *) of the
2992 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2994 Handle thread_oop(Thread::current(),
2995 JNIHandles::resolve_non_null(jni_thread));
2996 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2997 "must be initialized");
2998 set_threadObj(thread_oop());
2999 java_lang_Thread::set_thread(thread_oop(), this);
3001 if (prio == NoPriority) {
3002 prio = java_lang_Thread::priority(thread_oop());
3003 assert(prio != NoPriority, "A valid priority should be present");
3004 }
3006 // Push the Java priority down to the native thread; needs Threads_lock
3007 Thread::set_priority(this, prio);
3009 // Add the new thread to the Threads list and set it in motion.
3010 // We must have threads lock in order to call Threads::add.
3011 // It is crucial that we do not block before the thread is
3012 // added to the Threads list for if a GC happens, then the java_thread oop
3013 // will not be visited by GC.
3014 Threads::add(this);
3015 }
3017 oop JavaThread::current_park_blocker() {
3018 // Support for JSR-166 locks
3019 oop thread_oop = threadObj();
3020 if (thread_oop != NULL &&
3021 JDK_Version::current().supports_thread_park_blocker()) {
3022 return java_lang_Thread::park_blocker(thread_oop);
3023 }
3024 return NULL;
3025 }
3028 void JavaThread::print_stack_on(outputStream* st) {
3029 if (!has_last_Java_frame()) return;
3030 ResourceMark rm;
3031 HandleMark hm;
3033 RegisterMap reg_map(this);
3034 vframe* start_vf = last_java_vframe(®_map);
3035 int count = 0;
3036 for (vframe* f = start_vf; f; f = f->sender() ) {
3037 if (f->is_java_frame()) {
3038 javaVFrame* jvf = javaVFrame::cast(f);
3039 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3041 // Print out lock information
3042 if (JavaMonitorsInStackTrace) {
3043 jvf->print_lock_info_on(st, count);
3044 }
3045 } else {
3046 // Ignore non-Java frames
3047 }
3049 // Bail-out case for too deep stacks
3050 count++;
3051 if (MaxJavaStackTraceDepth == count) return;
3052 }
3053 }
3056 // JVMTI PopFrame support
3057 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3058 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3059 if (in_bytes(size_in_bytes) != 0) {
3060 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3061 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3062 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3063 }
3064 }
3066 void* JavaThread::popframe_preserved_args() {
3067 return _popframe_preserved_args;
3068 }
3070 ByteSize JavaThread::popframe_preserved_args_size() {
3071 return in_ByteSize(_popframe_preserved_args_size);
3072 }
3074 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3075 int sz = in_bytes(popframe_preserved_args_size());
3076 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3077 return in_WordSize(sz / wordSize);
3078 }
3080 void JavaThread::popframe_free_preserved_args() {
3081 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3082 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3083 _popframe_preserved_args = NULL;
3084 _popframe_preserved_args_size = 0;
3085 }
3087 #ifndef PRODUCT
3089 void JavaThread::trace_frames() {
3090 tty->print_cr("[Describe stack]");
3091 int frame_no = 1;
3092 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3093 tty->print(" %d. ", frame_no++);
3094 fst.current()->print_value_on(tty,this);
3095 tty->cr();
3096 }
3097 }
3099 class PrintAndVerifyOopClosure: public OopClosure {
3100 protected:
3101 template <class T> inline void do_oop_work(T* p) {
3102 oop obj = oopDesc::load_decode_heap_oop(p);
3103 if (obj == NULL) return;
3104 tty->print(INTPTR_FORMAT ": ", p);
3105 if (obj->is_oop_or_null()) {
3106 if (obj->is_objArray()) {
3107 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3108 } else {
3109 obj->print();
3110 }
3111 } else {
3112 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3113 }
3114 tty->cr();
3115 }
3116 public:
3117 virtual void do_oop(oop* p) { do_oop_work(p); }
3118 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3119 };
3122 static void oops_print(frame* f, const RegisterMap *map) {
3123 PrintAndVerifyOopClosure print;
3124 f->print_value();
3125 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3126 }
3128 // Print our all the locations that contain oops and whether they are
3129 // valid or not. This useful when trying to find the oldest frame
3130 // where an oop has gone bad since the frame walk is from youngest to
3131 // oldest.
3132 void JavaThread::trace_oops() {
3133 tty->print_cr("[Trace oops]");
3134 frames_do(oops_print);
3135 }
3138 #ifdef ASSERT
3139 // Print or validate the layout of stack frames
3140 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3141 ResourceMark rm;
3142 PRESERVE_EXCEPTION_MARK;
3143 FrameValues values;
3144 int frame_no = 0;
3145 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3146 fst.current()->describe(values, ++frame_no);
3147 if (depth == frame_no) break;
3148 }
3149 if (validate_only) {
3150 values.validate();
3151 } else {
3152 tty->print_cr("[Describe stack layout]");
3153 values.print(this);
3154 }
3155 }
3156 #endif
3158 void JavaThread::trace_stack_from(vframe* start_vf) {
3159 ResourceMark rm;
3160 int vframe_no = 1;
3161 for (vframe* f = start_vf; f; f = f->sender() ) {
3162 if (f->is_java_frame()) {
3163 javaVFrame::cast(f)->print_activation(vframe_no++);
3164 } else {
3165 f->print();
3166 }
3167 if (vframe_no > StackPrintLimit) {
3168 tty->print_cr("...<more frames>...");
3169 return;
3170 }
3171 }
3172 }
3175 void JavaThread::trace_stack() {
3176 if (!has_last_Java_frame()) return;
3177 ResourceMark rm;
3178 HandleMark hm;
3179 RegisterMap reg_map(this);
3180 trace_stack_from(last_java_vframe(®_map));
3181 }
3184 #endif // PRODUCT
3187 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3188 assert(reg_map != NULL, "a map must be given");
3189 frame f = last_frame();
3190 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3191 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3192 }
3193 return NULL;
3194 }
3197 Klass* JavaThread::security_get_caller_class(int depth) {
3198 vframeStream vfst(this);
3199 vfst.security_get_caller_frame(depth);
3200 if (!vfst.at_end()) {
3201 return vfst.method()->method_holder();
3202 }
3203 return NULL;
3204 }
3206 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3207 assert(thread->is_Compiler_thread(), "must be compiler thread");
3208 CompileBroker::compiler_thread_loop();
3209 }
3211 // Create a CompilerThread
3212 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3213 : JavaThread(&compiler_thread_entry) {
3214 _env = NULL;
3215 _log = NULL;
3216 _task = NULL;
3217 _queue = queue;
3218 _counters = counters;
3219 _buffer_blob = NULL;
3220 _scanned_nmethod = NULL;
3222 #ifndef PRODUCT
3223 _ideal_graph_printer = NULL;
3224 #endif
3225 }
3227 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
3228 JavaThread::oops_do(f, cld_f, cf);
3229 if (_scanned_nmethod != NULL && cf != NULL) {
3230 // Safepoints can occur when the sweeper is scanning an nmethod so
3231 // process it here to make sure it isn't unloaded in the middle of
3232 // a scan.
3233 cf->do_code_blob(_scanned_nmethod);
3234 }
3235 }
3237 // ======= Threads ========
3239 // The Threads class links together all active threads, and provides
3240 // operations over all threads. It is protected by its own Mutex
3241 // lock, which is also used in other contexts to protect thread
3242 // operations from having the thread being operated on from exiting
3243 // and going away unexpectedly (e.g., safepoint synchronization)
3245 JavaThread* Threads::_thread_list = NULL;
3246 int Threads::_number_of_threads = 0;
3247 int Threads::_number_of_non_daemon_threads = 0;
3248 int Threads::_return_code = 0;
3249 size_t JavaThread::_stack_size_at_create = 0;
3250 #ifdef ASSERT
3251 bool Threads::_vm_complete = false;
3252 #endif
3254 // All JavaThreads
3255 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3257 void os_stream();
3259 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3260 void Threads::threads_do(ThreadClosure* tc) {
3261 assert_locked_or_safepoint(Threads_lock);
3262 // ALL_JAVA_THREADS iterates through all JavaThreads
3263 ALL_JAVA_THREADS(p) {
3264 tc->do_thread(p);
3265 }
3266 // Someday we could have a table or list of all non-JavaThreads.
3267 // For now, just manually iterate through them.
3268 tc->do_thread(VMThread::vm_thread());
3269 Universe::heap()->gc_threads_do(tc);
3270 WatcherThread *wt = WatcherThread::watcher_thread();
3271 // Strictly speaking, the following NULL check isn't sufficient to make sure
3272 // the data for WatcherThread is still valid upon being examined. However,
3273 // considering that WatchThread terminates when the VM is on the way to
3274 // exit at safepoint, the chance of the above is extremely small. The right
3275 // way to prevent termination of WatcherThread would be to acquire
3276 // Terminator_lock, but we can't do that without violating the lock rank
3277 // checking in some cases.
3278 if (wt != NULL)
3279 tc->do_thread(wt);
3281 // If CompilerThreads ever become non-JavaThreads, add them here
3282 }
3284 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3286 extern void JDK_Version_init();
3288 // Check version
3289 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3291 // Initialize the output stream module
3292 ostream_init();
3294 // Process java launcher properties.
3295 Arguments::process_sun_java_launcher_properties(args);
3297 // Initialize the os module before using TLS
3298 os::init();
3300 // Initialize system properties.
3301 Arguments::init_system_properties();
3303 // So that JDK version can be used as a discrimintor when parsing arguments
3304 JDK_Version_init();
3306 // Update/Initialize System properties after JDK version number is known
3307 Arguments::init_version_specific_system_properties();
3309 // Parse arguments
3310 jint parse_result = Arguments::parse(args);
3311 if (parse_result != JNI_OK) return parse_result;
3313 if (PauseAtStartup) {
3314 os::pause();
3315 }
3317 #ifndef USDT2
3318 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3319 #else /* USDT2 */
3320 HOTSPOT_VM_INIT_BEGIN();
3321 #endif /* USDT2 */
3323 // Record VM creation timing statistics
3324 TraceVmCreationTime create_vm_timer;
3325 create_vm_timer.start();
3327 // Timing (must come after argument parsing)
3328 TraceTime timer("Create VM", TraceStartupTime);
3330 // Initialize the os module after parsing the args
3331 jint os_init_2_result = os::init_2();
3332 if (os_init_2_result != JNI_OK) return os_init_2_result;
3334 jint adjust_after_os_result = Arguments::adjust_after_os();
3335 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3337 // intialize TLS
3338 ThreadLocalStorage::init();
3340 // Bootstrap native memory tracking, so it can start recording memory
3341 // activities before worker thread is started. This is the first phase
3342 // of bootstrapping, VM is currently running in single-thread mode.
3343 MemTracker::bootstrap_single_thread();
3345 // Initialize output stream logging
3346 ostream_init_log();
3348 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3349 // Must be before create_vm_init_agents()
3350 if (Arguments::init_libraries_at_startup()) {
3351 convert_vm_init_libraries_to_agents();
3352 }
3354 // Launch -agentlib/-agentpath and converted -Xrun agents
3355 if (Arguments::init_agents_at_startup()) {
3356 create_vm_init_agents();
3357 }
3359 // Initialize Threads state
3360 _thread_list = NULL;
3361 _number_of_threads = 0;
3362 _number_of_non_daemon_threads = 0;
3364 // Initialize global data structures and create system classes in heap
3365 vm_init_globals();
3367 // Attach the main thread to this os thread
3368 JavaThread* main_thread = new JavaThread();
3369 main_thread->set_thread_state(_thread_in_vm);
3370 // must do this before set_active_handles and initialize_thread_local_storage
3371 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3372 // change the stack size recorded here to one based on the java thread
3373 // stacksize. This adjusted size is what is used to figure the placement
3374 // of the guard pages.
3375 main_thread->record_stack_base_and_size();
3376 main_thread->initialize_thread_local_storage();
3378 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3380 if (!main_thread->set_as_starting_thread()) {
3381 vm_shutdown_during_initialization(
3382 "Failed necessary internal allocation. Out of swap space");
3383 delete main_thread;
3384 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3385 return JNI_ENOMEM;
3386 }
3388 // Enable guard page *after* os::create_main_thread(), otherwise it would
3389 // crash Linux VM, see notes in os_linux.cpp.
3390 main_thread->create_stack_guard_pages();
3392 // Initialize Java-Level synchronization subsystem
3393 ObjectMonitor::Initialize() ;
3395 // Second phase of bootstrapping, VM is about entering multi-thread mode
3396 MemTracker::bootstrap_multi_thread();
3398 // Initialize global modules
3399 jint status = init_globals();
3400 if (status != JNI_OK) {
3401 delete main_thread;
3402 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3403 return status;
3404 }
3406 // Should be done after the heap is fully created
3407 main_thread->cache_global_variables();
3409 HandleMark hm;
3411 { MutexLocker mu(Threads_lock);
3412 Threads::add(main_thread);
3413 }
3415 // Any JVMTI raw monitors entered in onload will transition into
3416 // real raw monitor. VM is setup enough here for raw monitor enter.
3417 JvmtiExport::transition_pending_onload_raw_monitors();
3419 if (VerifyBeforeGC &&
3420 Universe::heap()->total_collections() >= VerifyGCStartAt) {
3421 Universe::heap()->prepare_for_verify();
3422 Universe::verify(); // make sure we're starting with a clean slate
3423 }
3425 // Fully start NMT
3426 MemTracker::start();
3428 // Create the VMThread
3429 { TraceTime timer("Start VMThread", TraceStartupTime);
3430 VMThread::create();
3431 Thread* vmthread = VMThread::vm_thread();
3433 if (!os::create_thread(vmthread, os::vm_thread))
3434 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3436 // Wait for the VM thread to become ready, and VMThread::run to initialize
3437 // Monitors can have spurious returns, must always check another state flag
3438 {
3439 MutexLocker ml(Notify_lock);
3440 os::start_thread(vmthread);
3441 while (vmthread->active_handles() == NULL) {
3442 Notify_lock->wait();
3443 }
3444 }
3445 }
3447 assert (Universe::is_fully_initialized(), "not initialized");
3448 EXCEPTION_MARK;
3450 // At this point, the Universe is initialized, but we have not executed
3451 // any byte code. Now is a good time (the only time) to dump out the
3452 // internal state of the JVM for sharing.
3453 if (DumpSharedSpaces) {
3454 MetaspaceShared::preload_and_dump(CHECK_0);
3455 ShouldNotReachHere();
3456 }
3458 // Always call even when there are not JVMTI environments yet, since environments
3459 // may be attached late and JVMTI must track phases of VM execution
3460 JvmtiExport::enter_start_phase();
3462 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3463 JvmtiExport::post_vm_start();
3465 {
3466 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3468 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3469 create_vm_init_libraries();
3470 }
3472 if (InitializeJavaLangString) {
3473 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3474 } else {
3475 warning("java.lang.String not initialized");
3476 }
3478 if (AggressiveOpts) {
3479 {
3480 // Forcibly initialize java/util/HashMap and mutate the private
3481 // static final "frontCacheEnabled" field before we start creating instances
3482 #ifdef ASSERT
3483 Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3484 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
3485 #endif
3486 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3487 KlassHandle k = KlassHandle(THREAD, k_o);
3488 guarantee(k.not_null(), "Must find java/util/HashMap");
3489 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3490 ik->initialize(CHECK_0);
3491 fieldDescriptor fd;
3492 // Possible we might not find this field; if so, don't break
3493 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3494 k()->java_mirror()->bool_field_put(fd.offset(), true);
3495 }
3496 }
3498 if (UseStringCache) {
3499 // Forcibly initialize java/lang/StringValue and mutate the private
3500 // static final "stringCacheEnabled" field before we start creating instances
3501 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3502 // Possible that StringValue isn't present: if so, silently don't break
3503 if (k_o != NULL) {
3504 KlassHandle k = KlassHandle(THREAD, k_o);
3505 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3506 ik->initialize(CHECK_0);
3507 fieldDescriptor fd;
3508 // Possible we might not find this field: if so, silently don't break
3509 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3510 k()->java_mirror()->bool_field_put(fd.offset(), true);
3511 }
3512 }
3513 }
3514 }
3516 // Initialize java_lang.System (needed before creating the thread)
3517 if (InitializeJavaLangSystem) {
3518 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3519 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3520 Handle thread_group = create_initial_thread_group(CHECK_0);
3521 Universe::set_main_thread_group(thread_group());
3522 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3523 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3524 main_thread->set_threadObj(thread_object);
3525 // Set thread status to running since main thread has
3526 // been started and running.
3527 java_lang_Thread::set_thread_status(thread_object,
3528 java_lang_Thread::RUNNABLE);
3530 // The VM creates & returns objects of this class. Make sure it's initialized.
3531 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3533 // The VM preresolves methods to these classes. Make sure that they get initialized
3534 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3535 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3536 call_initializeSystemClass(CHECK_0);
3538 // get the Java runtime name after java.lang.System is initialized
3539 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3540 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3541 } else {
3542 warning("java.lang.System not initialized");
3543 }
3545 // an instance of OutOfMemory exception has been allocated earlier
3546 if (InitializeJavaLangExceptionsErrors) {
3547 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3548 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3549 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3550 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3551 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3552 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3553 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3554 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3555 } else {
3556 warning("java.lang.OutOfMemoryError has not been initialized");
3557 warning("java.lang.NullPointerException has not been initialized");
3558 warning("java.lang.ClassCastException has not been initialized");
3559 warning("java.lang.ArrayStoreException has not been initialized");
3560 warning("java.lang.ArithmeticException has not been initialized");
3561 warning("java.lang.StackOverflowError has not been initialized");
3562 warning("java.lang.IllegalArgumentException has not been initialized");
3563 }
3564 }
3566 // See : bugid 4211085.
3567 // Background : the static initializer of java.lang.Compiler tries to read
3568 // property"java.compiler" and read & write property "java.vm.info".
3569 // When a security manager is installed through the command line
3570 // option "-Djava.security.manager", the above properties are not
3571 // readable and the static initializer for java.lang.Compiler fails
3572 // resulting in a NoClassDefFoundError. This can happen in any
3573 // user code which calls methods in java.lang.Compiler.
3574 // Hack : the hack is to pre-load and initialize this class, so that only
3575 // system domains are on the stack when the properties are read.
3576 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3577 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3578 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3579 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3580 // Once that is done, we should remove this hack.
3581 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3583 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3584 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3585 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3586 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3587 // This should also be taken out as soon as 4211383 gets fixed.
3588 reset_vm_info_property(CHECK_0);
3590 quicken_jni_functions();
3592 // Must be run after init_ft which initializes ft_enabled
3593 if (TRACE_INITIALIZE() != JNI_OK) {
3594 vm_exit_during_initialization("Failed to initialize tracing backend");
3595 }
3597 // Set flag that basic initialization has completed. Used by exceptions and various
3598 // debug stuff, that does not work until all basic classes have been initialized.
3599 set_init_completed();
3601 #ifndef USDT2
3602 HS_DTRACE_PROBE(hotspot, vm__init__end);
3603 #else /* USDT2 */
3604 HOTSPOT_VM_INIT_END();
3605 #endif /* USDT2 */
3607 // record VM initialization completion time
3608 #if INCLUDE_MANAGEMENT
3609 Management::record_vm_init_completed();
3610 #endif // INCLUDE_MANAGEMENT
3612 // Compute system loader. Note that this has to occur after set_init_completed, since
3613 // valid exceptions may be thrown in the process.
3614 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3615 // set_init_completed has just been called, causing exceptions not to be shortcut
3616 // anymore. We call vm_exit_during_initialization directly instead.
3617 SystemDictionary::compute_java_system_loader(THREAD);
3618 if (HAS_PENDING_EXCEPTION) {
3619 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3620 }
3622 #ifndef SERIALGC
3623 // Support for ConcurrentMarkSweep. This should be cleaned up
3624 // and better encapsulated. The ugly nested if test would go away
3625 // once things are properly refactored. XXX YSR
3626 if (UseConcMarkSweepGC || UseG1GC) {
3627 if (UseConcMarkSweepGC) {
3628 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3629 } else {
3630 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3631 }
3632 if (HAS_PENDING_EXCEPTION) {
3633 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3634 }
3635 }
3636 #endif // SERIALGC
3638 // Always call even when there are not JVMTI environments yet, since environments
3639 // may be attached late and JVMTI must track phases of VM execution
3640 JvmtiExport::enter_live_phase();
3642 // Signal Dispatcher needs to be started before VMInit event is posted
3643 os::signal_init();
3645 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3646 if (!DisableAttachMechanism) {
3647 if (StartAttachListener || AttachListener::init_at_startup()) {
3648 AttachListener::init();
3649 }
3650 }
3652 // Launch -Xrun agents
3653 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3654 // back-end can launch with -Xdebug -Xrunjdwp.
3655 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3656 create_vm_init_libraries();
3657 }
3659 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3660 JvmtiExport::post_vm_initialized();
3662 if (!TRACE_START()) {
3663 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3664 }
3666 if (CleanChunkPoolAsync) {
3667 Chunk::start_chunk_pool_cleaner_task();
3668 }
3670 // initialize compiler(s)
3671 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3672 CompileBroker::compilation_init();
3673 #endif
3675 #if INCLUDE_MANAGEMENT
3676 Management::initialize(THREAD);
3677 #endif // INCLUDE_MANAGEMENT
3679 if (HAS_PENDING_EXCEPTION) {
3680 // management agent fails to start possibly due to
3681 // configuration problem and is responsible for printing
3682 // stack trace if appropriate. Simply exit VM.
3683 vm_exit(1);
3684 }
3686 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3687 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3688 if (MemProfiling) MemProfiler::engage();
3689 StatSampler::engage();
3690 if (CheckJNICalls) JniPeriodicChecker::engage();
3692 BiasedLocking::init();
3694 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3695 call_postVMInitHook(THREAD);
3696 // The Java side of PostVMInitHook.run must deal with all
3697 // exceptions and provide means of diagnosis.
3698 if (HAS_PENDING_EXCEPTION) {
3699 CLEAR_PENDING_EXCEPTION;
3700 }
3701 }
3703 {
3704 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3705 // Make sure the watcher thread can be started by WatcherThread::start()
3706 // or by dynamic enrollment.
3707 WatcherThread::make_startable();
3708 // Start up the WatcherThread if there are any periodic tasks
3709 // NOTE: All PeriodicTasks should be registered by now. If they
3710 // aren't, late joiners might appear to start slowly (we might
3711 // take a while to process their first tick).
3712 if (PeriodicTask::num_tasks() > 0) {
3713 WatcherThread::start();
3714 }
3715 }
3717 // Give os specific code one last chance to start
3718 os::init_3();
3720 create_vm_timer.end();
3721 #ifdef ASSERT
3722 _vm_complete = true;
3723 #endif
3724 return JNI_OK;
3725 }
3727 // type for the Agent_OnLoad and JVM_OnLoad entry points
3728 extern "C" {
3729 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3730 }
3731 // Find a command line agent library and return its entry point for
3732 // -agentlib: -agentpath: -Xrun
3733 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3734 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3735 OnLoadEntry_t on_load_entry = NULL;
3736 void *library = agent->os_lib(); // check if we have looked it up before
3738 if (library == NULL) {
3739 char buffer[JVM_MAXPATHLEN];
3740 char ebuf[1024];
3741 const char *name = agent->name();
3742 const char *msg = "Could not find agent library ";
3744 if (agent->is_absolute_path()) {
3745 library = os::dll_load(name, ebuf, sizeof ebuf);
3746 if (library == NULL) {
3747 const char *sub_msg = " in absolute path, with error: ";
3748 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3749 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3750 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3751 // If we can't find the agent, exit.
3752 vm_exit_during_initialization(buf, NULL);
3753 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3754 }
3755 } else {
3756 // Try to load the agent from the standard dll directory
3757 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3758 name)) {
3759 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3760 }
3761 #ifdef KERNEL
3762 // Download instrument dll
3763 if (library == NULL && strcmp(name, "instrument") == 0) {
3764 char *props = Arguments::get_kernel_properties();
3765 char *home = Arguments::get_java_home();
3766 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false"
3767 " sun.jkernel.DownloadManager -download client_jvm";
3768 size_t length = strlen(props) + strlen(home) + strlen(fmt) + 1;
3769 char *cmd = NEW_C_HEAP_ARRAY(char, length, mtThread);
3770 jio_snprintf(cmd, length, fmt, home, props);
3771 int status = os::fork_and_exec(cmd);
3772 FreeHeap(props);
3773 if (status == -1) {
3774 warning(cmd);
3775 vm_exit_during_initialization("fork_and_exec failed: %s",
3776 strerror(errno));
3777 }
3778 FREE_C_HEAP_ARRAY(char, cmd, mtThread);
3779 // when this comes back the instrument.dll should be where it belongs.
3780 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3781 }
3782 #endif // KERNEL
3783 if (library == NULL) { // Try the local directory
3784 char ns[1] = {0};
3785 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3786 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3787 }
3788 if (library == NULL) {
3789 const char *sub_msg = " on the library path, with error: ";
3790 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3791 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3792 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3793 // If we can't find the agent, exit.
3794 vm_exit_during_initialization(buf, NULL);
3795 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3796 }
3797 }
3798 }
3799 agent->set_os_lib(library);
3800 }
3802 // Find the OnLoad function.
3803 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3804 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index]));
3805 if (on_load_entry != NULL) break;
3806 }
3807 return on_load_entry;
3808 }
3810 // Find the JVM_OnLoad entry point
3811 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3812 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3813 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3814 }
3816 // Find the Agent_OnLoad entry point
3817 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3818 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3819 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3820 }
3822 // For backwards compatibility with -Xrun
3823 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3824 // treated like -agentpath:
3825 // Must be called before agent libraries are created
3826 void Threads::convert_vm_init_libraries_to_agents() {
3827 AgentLibrary* agent;
3828 AgentLibrary* next;
3830 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3831 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3832 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3834 // If there is an JVM_OnLoad function it will get called later,
3835 // otherwise see if there is an Agent_OnLoad
3836 if (on_load_entry == NULL) {
3837 on_load_entry = lookup_agent_on_load(agent);
3838 if (on_load_entry != NULL) {
3839 // switch it to the agent list -- so that Agent_OnLoad will be called,
3840 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3841 Arguments::convert_library_to_agent(agent);
3842 } else {
3843 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3844 }
3845 }
3846 }
3847 }
3849 // Create agents for -agentlib: -agentpath: and converted -Xrun
3850 // Invokes Agent_OnLoad
3851 // Called very early -- before JavaThreads exist
3852 void Threads::create_vm_init_agents() {
3853 extern struct JavaVM_ main_vm;
3854 AgentLibrary* agent;
3856 JvmtiExport::enter_onload_phase();
3858 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3859 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3861 if (on_load_entry != NULL) {
3862 // Invoke the Agent_OnLoad function
3863 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3864 if (err != JNI_OK) {
3865 vm_exit_during_initialization("agent library failed to init", agent->name());
3866 }
3867 } else {
3868 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3869 }
3870 }
3871 JvmtiExport::enter_primordial_phase();
3872 }
3874 extern "C" {
3875 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3876 }
3878 void Threads::shutdown_vm_agents() {
3879 // Send any Agent_OnUnload notifications
3880 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3881 extern struct JavaVM_ main_vm;
3882 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3884 // Find the Agent_OnUnload function.
3885 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3886 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3887 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3889 // Invoke the Agent_OnUnload function
3890 if (unload_entry != NULL) {
3891 JavaThread* thread = JavaThread::current();
3892 ThreadToNativeFromVM ttn(thread);
3893 HandleMark hm(thread);
3894 (*unload_entry)(&main_vm);
3895 break;
3896 }
3897 }
3898 }
3899 }
3901 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3902 // Invokes JVM_OnLoad
3903 void Threads::create_vm_init_libraries() {
3904 extern struct JavaVM_ main_vm;
3905 AgentLibrary* agent;
3907 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3908 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3910 if (on_load_entry != NULL) {
3911 // Invoke the JVM_OnLoad function
3912 JavaThread* thread = JavaThread::current();
3913 ThreadToNativeFromVM ttn(thread);
3914 HandleMark hm(thread);
3915 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3916 if (err != JNI_OK) {
3917 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3918 }
3919 } else {
3920 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3921 }
3922 }
3923 }
3925 // Last thread running calls java.lang.Shutdown.shutdown()
3926 void JavaThread::invoke_shutdown_hooks() {
3927 HandleMark hm(this);
3929 // We could get here with a pending exception, if so clear it now.
3930 if (this->has_pending_exception()) {
3931 this->clear_pending_exception();
3932 }
3934 EXCEPTION_MARK;
3935 Klass* k =
3936 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3937 THREAD);
3938 if (k != NULL) {
3939 // SystemDictionary::resolve_or_null will return null if there was
3940 // an exception. If we cannot load the Shutdown class, just don't
3941 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3942 // and finalizers (if runFinalizersOnExit is set) won't be run.
3943 // Note that if a shutdown hook was registered or runFinalizersOnExit
3944 // was called, the Shutdown class would have already been loaded
3945 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3946 instanceKlassHandle shutdown_klass (THREAD, k);
3947 JavaValue result(T_VOID);
3948 JavaCalls::call_static(&result,
3949 shutdown_klass,
3950 vmSymbols::shutdown_method_name(),
3951 vmSymbols::void_method_signature(),
3952 THREAD);
3953 }
3954 CLEAR_PENDING_EXCEPTION;
3955 }
3957 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3958 // the program falls off the end of main(). Another VM exit path is through
3959 // vm_exit() when the program calls System.exit() to return a value or when
3960 // there is a serious error in VM. The two shutdown paths are not exactly
3961 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3962 // and VM_Exit op at VM level.
3963 //
3964 // Shutdown sequence:
3965 // + Shutdown native memory tracking if it is on
3966 // + Wait until we are the last non-daemon thread to execute
3967 // <-- every thing is still working at this moment -->
3968 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3969 // shutdown hooks, run finalizers if finalization-on-exit
3970 // + Call before_exit(), prepare for VM exit
3971 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3972 // currently the only user of this mechanism is File.deleteOnExit())
3973 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3974 // post thread end and vm death events to JVMTI,
3975 // stop signal thread
3976 // + Call JavaThread::exit(), it will:
3977 // > release JNI handle blocks, remove stack guard pages
3978 // > remove this thread from Threads list
3979 // <-- no more Java code from this thread after this point -->
3980 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3981 // the compiler threads at safepoint
3982 // <-- do not use anything that could get blocked by Safepoint -->
3983 // + Disable tracing at JNI/JVM barriers
3984 // + Set _vm_exited flag for threads that are still running native code
3985 // + Delete this thread
3986 // + Call exit_globals()
3987 // > deletes tty
3988 // > deletes PerfMemory resources
3989 // + Return to caller
3991 bool Threads::destroy_vm() {
3992 JavaThread* thread = JavaThread::current();
3994 #ifdef ASSERT
3995 _vm_complete = false;
3996 #endif
3997 // Wait until we are the last non-daemon thread to execute
3998 { MutexLocker nu(Threads_lock);
3999 while (Threads::number_of_non_daemon_threads() > 1 )
4000 // This wait should make safepoint checks, wait without a timeout,
4001 // and wait as a suspend-equivalent condition.
4002 //
4003 // Note: If the FlatProfiler is running and this thread is waiting
4004 // for another non-daemon thread to finish, then the FlatProfiler
4005 // is waiting for the external suspend request on this thread to
4006 // complete. wait_for_ext_suspend_completion() will eventually
4007 // timeout, but that takes time. Making this wait a suspend-
4008 // equivalent condition solves that timeout problem.
4009 //
4010 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4011 Mutex::_as_suspend_equivalent_flag);
4012 }
4014 // Hang forever on exit if we are reporting an error.
4015 if (ShowMessageBoxOnError && is_error_reported()) {
4016 os::infinite_sleep();
4017 }
4018 os::wait_for_keypress_at_exit();
4020 if (JDK_Version::is_jdk12x_version()) {
4021 // We are the last thread running, so check if finalizers should be run.
4022 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4023 HandleMark rm(thread);
4024 Universe::run_finalizers_on_exit();
4025 } else {
4026 // run Java level shutdown hooks
4027 thread->invoke_shutdown_hooks();
4028 }
4030 before_exit(thread);
4032 thread->exit(true);
4034 // Stop VM thread.
4035 {
4036 // 4945125 The vm thread comes to a safepoint during exit.
4037 // GC vm_operations can get caught at the safepoint, and the
4038 // heap is unparseable if they are caught. Grab the Heap_lock
4039 // to prevent this. The GC vm_operations will not be able to
4040 // queue until after the vm thread is dead.
4041 // After this point, we'll never emerge out of the safepoint before
4042 // the VM exits, so concurrent GC threads do not need to be explicitly
4043 // stopped; they remain inactive until the process exits.
4044 // Note: some concurrent G1 threads may be running during a safepoint,
4045 // but these will not be accessing the heap, just some G1-specific side
4046 // data structures that are not accessed by any other threads but them
4047 // after this point in a terminal safepoint.
4049 MutexLocker ml(Heap_lock);
4051 VMThread::wait_for_vm_thread_exit();
4052 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4053 VMThread::destroy();
4054 }
4056 // clean up ideal graph printers
4057 #if defined(COMPILER2) && !defined(PRODUCT)
4058 IdealGraphPrinter::clean_up();
4059 #endif
4061 // Now, all Java threads are gone except daemon threads. Daemon threads
4062 // running Java code or in VM are stopped by the Safepoint. However,
4063 // daemon threads executing native code are still running. But they
4064 // will be stopped at native=>Java/VM barriers. Note that we can't
4065 // simply kill or suspend them, as it is inherently deadlock-prone.
4067 #ifndef PRODUCT
4068 // disable function tracing at JNI/JVM barriers
4069 TraceJNICalls = false;
4070 TraceJVMCalls = false;
4071 TraceRuntimeCalls = false;
4072 #endif
4074 VM_Exit::set_vm_exited();
4076 notify_vm_shutdown();
4078 delete thread;
4080 // exit_globals() will delete tty
4081 exit_globals();
4083 return true;
4084 }
4087 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4088 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4089 return is_supported_jni_version(version);
4090 }
4093 jboolean Threads::is_supported_jni_version(jint version) {
4094 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4095 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4096 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4097 return JNI_FALSE;
4098 }
4101 void Threads::add(JavaThread* p, bool force_daemon) {
4102 // The threads lock must be owned at this point
4103 assert_locked_or_safepoint(Threads_lock);
4105 // See the comment for this method in thread.hpp for its purpose and
4106 // why it is called here.
4107 p->initialize_queues();
4108 p->set_next(_thread_list);
4109 _thread_list = p;
4110 _number_of_threads++;
4111 oop threadObj = p->threadObj();
4112 bool daemon = true;
4113 // Bootstrapping problem: threadObj can be null for initial
4114 // JavaThread (or for threads attached via JNI)
4115 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4116 _number_of_non_daemon_threads++;
4117 daemon = false;
4118 }
4120 p->set_safepoint_visible(true);
4122 ThreadService::add_thread(p, daemon);
4124 // Possible GC point.
4125 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4126 }
4128 void Threads::remove(JavaThread* p) {
4129 // Extra scope needed for Thread_lock, so we can check
4130 // that we do not remove thread without safepoint code notice
4131 { MutexLocker ml(Threads_lock);
4133 assert(includes(p), "p must be present");
4135 JavaThread* current = _thread_list;
4136 JavaThread* prev = NULL;
4138 while (current != p) {
4139 prev = current;
4140 current = current->next();
4141 }
4143 if (prev) {
4144 prev->set_next(current->next());
4145 } else {
4146 _thread_list = p->next();
4147 }
4148 _number_of_threads--;
4149 oop threadObj = p->threadObj();
4150 bool daemon = true;
4151 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4152 _number_of_non_daemon_threads--;
4153 daemon = false;
4155 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4156 // on destroy_vm will wake up.
4157 if (number_of_non_daemon_threads() == 1)
4158 Threads_lock->notify_all();
4159 }
4160 ThreadService::remove_thread(p, daemon);
4162 // Make sure that safepoint code disregard this thread. This is needed since
4163 // the thread might mess around with locks after this point. This can cause it
4164 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4165 // of this thread since it is removed from the queue.
4166 p->set_terminated_value();
4168 // Now, this thread is not visible to safepoint
4169 p->set_safepoint_visible(false);
4170 // once the thread becomes safepoint invisible, we can not use its per-thread
4171 // recorder. And Threads::do_threads() no longer walks this thread, so we have
4172 // to release its per-thread recorder here.
4173 MemTracker::thread_exiting(p);
4174 } // unlock Threads_lock
4176 // Since Events::log uses a lock, we grab it outside the Threads_lock
4177 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4178 }
4180 // Threads_lock must be held when this is called (or must be called during a safepoint)
4181 bool Threads::includes(JavaThread* p) {
4182 assert(Threads_lock->is_locked(), "sanity check");
4183 ALL_JAVA_THREADS(q) {
4184 if (q == p ) {
4185 return true;
4186 }
4187 }
4188 return false;
4189 }
4191 // Operations on the Threads list for GC. These are not explicitly locked,
4192 // but the garbage collector must provide a safe context for them to run.
4193 // In particular, these things should never be called when the Threads_lock
4194 // is held by some other thread. (Note: the Safepoint abstraction also
4195 // uses the Threads_lock to gurantee this property. It also makes sure that
4196 // all threads gets blocked when exiting or starting).
4198 void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4199 ALL_JAVA_THREADS(p) {
4200 p->oops_do(f, cld_f, cf);
4201 }
4202 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4203 }
4205 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4206 // Introduce a mechanism allowing parallel threads to claim threads as
4207 // root groups. Overhead should be small enough to use all the time,
4208 // even in sequential code.
4209 SharedHeap* sh = SharedHeap::heap();
4210 // Cannot yet substitute active_workers for n_par_threads
4211 // because of G1CollectedHeap::verify() use of
4212 // SharedHeap::process_strong_roots(). n_par_threads == 0 will
4213 // turn off parallelism in process_strong_roots while active_workers
4214 // is being used for parallelism elsewhere.
4215 bool is_par = sh->n_par_threads() > 0;
4216 assert(!is_par ||
4217 (SharedHeap::heap()->n_par_threads() ==
4218 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4219 int cp = SharedHeap::heap()->strong_roots_parity();
4220 ALL_JAVA_THREADS(p) {
4221 if (p->claim_oops_do(is_par, cp)) {
4222 p->oops_do(f, cld_f, cf);
4223 }
4224 }
4225 VMThread* vmt = VMThread::vm_thread();
4226 if (vmt->claim_oops_do(is_par, cp)) {
4227 vmt->oops_do(f, cld_f, cf);
4228 }
4229 }
4231 #ifndef SERIALGC
4232 // Used by ParallelScavenge
4233 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4234 ALL_JAVA_THREADS(p) {
4235 q->enqueue(new ThreadRootsTask(p));
4236 }
4237 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4238 }
4240 // Used by Parallel Old
4241 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4242 ALL_JAVA_THREADS(p) {
4243 q->enqueue(new ThreadRootsMarkingTask(p));
4244 }
4245 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4246 }
4247 #endif // SERIALGC
4249 void Threads::nmethods_do(CodeBlobClosure* cf) {
4250 ALL_JAVA_THREADS(p) {
4251 p->nmethods_do(cf);
4252 }
4253 VMThread::vm_thread()->nmethods_do(cf);
4254 }
4256 void Threads::metadata_do(void f(Metadata*)) {
4257 ALL_JAVA_THREADS(p) {
4258 p->metadata_do(f);
4259 }
4260 }
4262 void Threads::gc_epilogue() {
4263 ALL_JAVA_THREADS(p) {
4264 p->gc_epilogue();
4265 }
4266 }
4268 void Threads::gc_prologue() {
4269 ALL_JAVA_THREADS(p) {
4270 p->gc_prologue();
4271 }
4272 }
4274 void Threads::deoptimized_wrt_marked_nmethods() {
4275 ALL_JAVA_THREADS(p) {
4276 p->deoptimized_wrt_marked_nmethods();
4277 }
4278 }
4281 // Get count Java threads that are waiting to enter the specified monitor.
4282 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4283 address monitor, bool doLock) {
4284 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4285 "must grab Threads_lock or be at safepoint");
4286 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4288 int i = 0;
4289 {
4290 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4291 ALL_JAVA_THREADS(p) {
4292 if (p->is_Compiler_thread()) continue;
4294 address pending = (address)p->current_pending_monitor();
4295 if (pending == monitor) { // found a match
4296 if (i < count) result->append(p); // save the first count matches
4297 i++;
4298 }
4299 }
4300 }
4301 return result;
4302 }
4305 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4306 assert(doLock ||
4307 Threads_lock->owned_by_self() ||
4308 SafepointSynchronize::is_at_safepoint(),
4309 "must grab Threads_lock or be at safepoint");
4311 // NULL owner means not locked so we can skip the search
4312 if (owner == NULL) return NULL;
4314 {
4315 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4316 ALL_JAVA_THREADS(p) {
4317 // first, see if owner is the address of a Java thread
4318 if (owner == (address)p) return p;
4319 }
4320 }
4321 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
4322 if (UseHeavyMonitors) return NULL;
4324 //
4325 // If we didn't find a matching Java thread and we didn't force use of
4326 // heavyweight monitors, then the owner is the stack address of the
4327 // Lock Word in the owning Java thread's stack.
4328 //
4329 JavaThread* the_owner = NULL;
4330 {
4331 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4332 ALL_JAVA_THREADS(q) {
4333 if (q->is_lock_owned(owner)) {
4334 the_owner = q;
4335 break;
4336 }
4337 }
4338 }
4339 assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
4340 return the_owner;
4341 }
4343 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4344 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4345 char buf[32];
4346 st->print_cr(os::local_time_string(buf, sizeof(buf)));
4348 st->print_cr("Full thread dump %s (%s %s):",
4349 Abstract_VM_Version::vm_name(),
4350 Abstract_VM_Version::vm_release(),
4351 Abstract_VM_Version::vm_info_string()
4352 );
4353 st->cr();
4355 #ifndef SERIALGC
4356 // Dump concurrent locks
4357 ConcurrentLocksDump concurrent_locks;
4358 if (print_concurrent_locks) {
4359 concurrent_locks.dump_at_safepoint();
4360 }
4361 #endif // SERIALGC
4363 ALL_JAVA_THREADS(p) {
4364 ResourceMark rm;
4365 p->print_on(st);
4366 if (print_stacks) {
4367 if (internal_format) {
4368 p->trace_stack();
4369 } else {
4370 p->print_stack_on(st);
4371 }
4372 }
4373 st->cr();
4374 #ifndef SERIALGC
4375 if (print_concurrent_locks) {
4376 concurrent_locks.print_locks_on(p, st);
4377 }
4378 #endif // SERIALGC
4379 }
4381 VMThread::vm_thread()->print_on(st);
4382 st->cr();
4383 Universe::heap()->print_gc_threads_on(st);
4384 WatcherThread* wt = WatcherThread::watcher_thread();
4385 if (wt != NULL) {
4386 wt->print_on(st);
4387 st->cr();
4388 }
4389 CompileBroker::print_compiler_threads_on(st);
4390 st->flush();
4391 }
4393 // Threads::print_on_error() is called by fatal error handler. It's possible
4394 // that VM is not at safepoint and/or current thread is inside signal handler.
4395 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4396 // memory (even in resource area), it might deadlock the error handler.
4397 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4398 bool found_current = false;
4399 st->print_cr("Java Threads: ( => current thread )");
4400 ALL_JAVA_THREADS(thread) {
4401 bool is_current = (current == thread);
4402 found_current = found_current || is_current;
4404 st->print("%s", is_current ? "=>" : " ");
4406 st->print(PTR_FORMAT, thread);
4407 st->print(" ");
4408 thread->print_on_error(st, buf, buflen);
4409 st->cr();
4410 }
4411 st->cr();
4413 st->print_cr("Other Threads:");
4414 if (VMThread::vm_thread()) {
4415 bool is_current = (current == VMThread::vm_thread());
4416 found_current = found_current || is_current;
4417 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4419 st->print(PTR_FORMAT, VMThread::vm_thread());
4420 st->print(" ");
4421 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4422 st->cr();
4423 }
4424 WatcherThread* wt = WatcherThread::watcher_thread();
4425 if (wt != NULL) {
4426 bool is_current = (current == wt);
4427 found_current = found_current || is_current;
4428 st->print("%s", is_current ? "=>" : " ");
4430 st->print(PTR_FORMAT, wt);
4431 st->print(" ");
4432 wt->print_on_error(st, buf, buflen);
4433 st->cr();
4434 }
4435 if (!found_current) {
4436 st->cr();
4437 st->print("=>" PTR_FORMAT " (exited) ", current);
4438 current->print_on_error(st, buf, buflen);
4439 st->cr();
4440 }
4441 }
4443 // Internal SpinLock and Mutex
4444 // Based on ParkEvent
4446 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4447 //
4448 // We employ SpinLocks _only for low-contention, fixed-length
4449 // short-duration critical sections where we're concerned
4450 // about native mutex_t or HotSpot Mutex:: latency.
4451 // The mux construct provides a spin-then-block mutual exclusion
4452 // mechanism.
4453 //
4454 // Testing has shown that contention on the ListLock guarding gFreeList
4455 // is common. If we implement ListLock as a simple SpinLock it's common
4456 // for the JVM to devolve to yielding with little progress. This is true
4457 // despite the fact that the critical sections protected by ListLock are
4458 // extremely short.
4459 //
4460 // TODO-FIXME: ListLock should be of type SpinLock.
4461 // We should make this a 1st-class type, integrated into the lock
4462 // hierarchy as leaf-locks. Critically, the SpinLock structure
4463 // should have sufficient padding to avoid false-sharing and excessive
4464 // cache-coherency traffic.
4467 typedef volatile int SpinLockT ;
4469 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4470 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4471 return ; // normal fast-path return
4472 }
4474 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4475 TEVENT (SpinAcquire - ctx) ;
4476 int ctr = 0 ;
4477 int Yields = 0 ;
4478 for (;;) {
4479 while (*adr != 0) {
4480 ++ctr ;
4481 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4482 if (Yields > 5) {
4483 // Consider using a simple NakedSleep() instead.
4484 // Then SpinAcquire could be called by non-JVM threads
4485 Thread::current()->_ParkEvent->park(1) ;
4486 } else {
4487 os::NakedYield() ;
4488 ++Yields ;
4489 }
4490 } else {
4491 SpinPause() ;
4492 }
4493 }
4494 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4495 }
4496 }
4498 void Thread::SpinRelease (volatile int * adr) {
4499 assert (*adr != 0, "invariant") ;
4500 OrderAccess::fence() ; // guarantee at least release consistency.
4501 // Roach-motel semantics.
4502 // It's safe if subsequent LDs and STs float "up" into the critical section,
4503 // but prior LDs and STs within the critical section can't be allowed
4504 // to reorder or float past the ST that releases the lock.
4505 *adr = 0 ;
4506 }
4508 // muxAcquire and muxRelease:
4509 //
4510 // * muxAcquire and muxRelease support a single-word lock-word construct.
4511 // The LSB of the word is set IFF the lock is held.
4512 // The remainder of the word points to the head of a singly-linked list
4513 // of threads blocked on the lock.
4514 //
4515 // * The current implementation of muxAcquire-muxRelease uses its own
4516 // dedicated Thread._MuxEvent instance. If we're interested in
4517 // minimizing the peak number of extant ParkEvent instances then
4518 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4519 // as certain invariants were satisfied. Specifically, care would need
4520 // to be taken with regards to consuming unpark() "permits".
4521 // A safe rule of thumb is that a thread would never call muxAcquire()
4522 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4523 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4524 // consume an unpark() permit intended for monitorenter, for instance.
4525 // One way around this would be to widen the restricted-range semaphore
4526 // implemented in park(). Another alternative would be to provide
4527 // multiple instances of the PlatformEvent() for each thread. One
4528 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4529 //
4530 // * Usage:
4531 // -- Only as leaf locks
4532 // -- for short-term locking only as muxAcquire does not perform
4533 // thread state transitions.
4534 //
4535 // Alternatives:
4536 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4537 // but with parking or spin-then-park instead of pure spinning.
4538 // * Use Taura-Oyama-Yonenzawa locks.
4539 // * It's possible to construct a 1-0 lock if we encode the lockword as
4540 // (List,LockByte). Acquire will CAS the full lockword while Release
4541 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4542 // acquiring threads use timers (ParkTimed) to detect and recover from
4543 // the stranding window. Thread/Node structures must be aligned on 256-byte
4544 // boundaries by using placement-new.
4545 // * Augment MCS with advisory back-link fields maintained with CAS().
4546 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4547 // The validity of the backlinks must be ratified before we trust the value.
4548 // If the backlinks are invalid the exiting thread must back-track through the
4549 // the forward links, which are always trustworthy.
4550 // * Add a successor indication. The LockWord is currently encoded as
4551 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4552 // to provide the usual futile-wakeup optimization.
4553 // See RTStt for details.
4554 // * Consider schedctl.sc_nopreempt to cover the critical section.
4555 //
4558 typedef volatile intptr_t MutexT ; // Mux Lock-word
4559 enum MuxBits { LOCKBIT = 1 } ;
4561 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4562 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4563 if (w == 0) return ;
4564 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4565 return ;
4566 }
4568 TEVENT (muxAcquire - Contention) ;
4569 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4570 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4571 for (;;) {
4572 int its = (os::is_MP() ? 100 : 0) + 1 ;
4574 // Optional spin phase: spin-then-park strategy
4575 while (--its >= 0) {
4576 w = *Lock ;
4577 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4578 return ;
4579 }
4580 }
4582 Self->reset() ;
4583 Self->OnList = intptr_t(Lock) ;
4584 // The following fence() isn't _strictly necessary as the subsequent
4585 // CAS() both serializes execution and ratifies the fetched *Lock value.
4586 OrderAccess::fence();
4587 for (;;) {
4588 w = *Lock ;
4589 if ((w & LOCKBIT) == 0) {
4590 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4591 Self->OnList = 0 ; // hygiene - allows stronger asserts
4592 return ;
4593 }
4594 continue ; // Interference -- *Lock changed -- Just retry
4595 }
4596 assert (w & LOCKBIT, "invariant") ;
4597 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4598 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4599 }
4601 while (Self->OnList != 0) {
4602 Self->park() ;
4603 }
4604 }
4605 }
4607 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4608 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4609 if (w == 0) return ;
4610 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4611 return ;
4612 }
4614 TEVENT (muxAcquire - Contention) ;
4615 ParkEvent * ReleaseAfter = NULL ;
4616 if (ev == NULL) {
4617 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4618 }
4619 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4620 for (;;) {
4621 guarantee (ev->OnList == 0, "invariant") ;
4622 int its = (os::is_MP() ? 100 : 0) + 1 ;
4624 // Optional spin phase: spin-then-park strategy
4625 while (--its >= 0) {
4626 w = *Lock ;
4627 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4628 if (ReleaseAfter != NULL) {
4629 ParkEvent::Release (ReleaseAfter) ;
4630 }
4631 return ;
4632 }
4633 }
4635 ev->reset() ;
4636 ev->OnList = intptr_t(Lock) ;
4637 // The following fence() isn't _strictly necessary as the subsequent
4638 // CAS() both serializes execution and ratifies the fetched *Lock value.
4639 OrderAccess::fence();
4640 for (;;) {
4641 w = *Lock ;
4642 if ((w & LOCKBIT) == 0) {
4643 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4644 ev->OnList = 0 ;
4645 // We call ::Release while holding the outer lock, thus
4646 // artificially lengthening the critical section.
4647 // Consider deferring the ::Release() until the subsequent unlock(),
4648 // after we've dropped the outer lock.
4649 if (ReleaseAfter != NULL) {
4650 ParkEvent::Release (ReleaseAfter) ;
4651 }
4652 return ;
4653 }
4654 continue ; // Interference -- *Lock changed -- Just retry
4655 }
4656 assert (w & LOCKBIT, "invariant") ;
4657 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4658 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4659 }
4661 while (ev->OnList != 0) {
4662 ev->park() ;
4663 }
4664 }
4665 }
4667 // Release() must extract a successor from the list and then wake that thread.
4668 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4669 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4670 // Release() would :
4671 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4672 // (B) Extract a successor from the private list "in-hand"
4673 // (C) attempt to CAS() the residual back into *Lock over null.
4674 // If there were any newly arrived threads and the CAS() would fail.
4675 // In that case Release() would detach the RATs, re-merge the list in-hand
4676 // with the RATs and repeat as needed. Alternately, Release() might
4677 // detach and extract a successor, but then pass the residual list to the wakee.
4678 // The wakee would be responsible for reattaching and remerging before it
4679 // competed for the lock.
4680 //
4681 // Both "pop" and DMR are immune from ABA corruption -- there can be
4682 // multiple concurrent pushers, but only one popper or detacher.
4683 // This implementation pops from the head of the list. This is unfair,
4684 // but tends to provide excellent throughput as hot threads remain hot.
4685 // (We wake recently run threads first).
4687 void Thread::muxRelease (volatile intptr_t * Lock) {
4688 for (;;) {
4689 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4690 assert (w & LOCKBIT, "invariant") ;
4691 if (w == LOCKBIT) return ;
4692 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4693 assert (List != NULL, "invariant") ;
4694 assert (List->OnList == intptr_t(Lock), "invariant") ;
4695 ParkEvent * nxt = List->ListNext ;
4697 // The following CAS() releases the lock and pops the head element.
4698 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4699 continue ;
4700 }
4701 List->OnList = 0 ;
4702 OrderAccess::fence() ;
4703 List->unpark () ;
4704 return ;
4705 }
4706 }
4709 void Threads::verify() {
4710 ALL_JAVA_THREADS(p) {
4711 p->verify();
4712 }
4713 VMThread* thread = VMThread::vm_thread();
4714 if (thread != NULL) thread->verify();
4715 }