Tue, 13 Feb 2018 15:48:23 +0100
8041626: Shutdown tracing event
Reviewed-by: dholmes, alanb, rriggs
1 /*
2 * Copyright (c) 1997, 2018, 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 "jfr/jfrEvents.hpp"
36 #include "jfr/support/jfrThreadId.hpp"
37 #include "jvmtifiles/jvmtiEnv.hpp"
38 #include "memory/gcLocker.inline.hpp"
39 #include "memory/metaspaceShared.hpp"
40 #include "memory/oopFactory.hpp"
41 #include "memory/universe.inline.hpp"
42 #include "oops/instanceKlass.hpp"
43 #include "oops/objArrayOop.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "oops/symbol.hpp"
46 #include "prims/jvm_misc.hpp"
47 #include "prims/jvmtiExport.hpp"
48 #include "prims/jvmtiThreadState.hpp"
49 #include "prims/privilegedStack.hpp"
50 #include "runtime/arguments.hpp"
51 #include "runtime/biasedLocking.hpp"
52 #include "runtime/deoptimization.hpp"
53 #include "runtime/fprofiler.hpp"
54 #include "runtime/frame.inline.hpp"
55 #include "runtime/init.hpp"
56 #include "runtime/interfaceSupport.hpp"
57 #include "runtime/java.hpp"
58 #include "runtime/javaCalls.hpp"
59 #include "runtime/jniPeriodicChecker.hpp"
60 #include "runtime/memprofiler.hpp"
61 #include "runtime/mutexLocker.hpp"
62 #include "runtime/objectMonitor.hpp"
63 #include "runtime/orderAccess.inline.hpp"
64 #include "runtime/osThread.hpp"
65 #include "runtime/safepoint.hpp"
66 #include "runtime/sharedRuntime.hpp"
67 #include "runtime/statSampler.hpp"
68 #include "runtime/stubRoutines.hpp"
69 #include "runtime/task.hpp"
70 #include "runtime/thread.inline.hpp"
71 #include "runtime/threadCritical.hpp"
72 #include "runtime/threadLocalStorage.hpp"
73 #include "runtime/vframe.hpp"
74 #include "runtime/vframeArray.hpp"
75 #include "runtime/vframe_hp.hpp"
76 #include "runtime/vmThread.hpp"
77 #include "runtime/vm_operations.hpp"
78 #include "services/attachListener.hpp"
79 #include "services/management.hpp"
80 #include "services/memTracker.hpp"
81 #include "services/threadService.hpp"
82 #include "utilities/defaultStream.hpp"
83 #include "utilities/dtrace.hpp"
84 #include "utilities/events.hpp"
85 #include "utilities/preserveException.hpp"
86 #include "utilities/macros.hpp"
87 #ifdef TARGET_OS_FAMILY_linux
88 # include "os_linux.inline.hpp"
89 #endif
90 #ifdef TARGET_OS_FAMILY_solaris
91 # include "os_solaris.inline.hpp"
92 #endif
93 #ifdef TARGET_OS_FAMILY_windows
94 # include "os_windows.inline.hpp"
95 #endif
96 #ifdef TARGET_OS_FAMILY_bsd
97 # include "os_bsd.inline.hpp"
98 #endif
99 #if INCLUDE_ALL_GCS
100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
102 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
103 #endif // INCLUDE_ALL_GCS
104 #ifdef COMPILER1
105 #include "c1/c1_Compiler.hpp"
106 #endif
107 #ifdef COMPILER2
108 #include "opto/c2compiler.hpp"
109 #include "opto/idealGraphPrinter.hpp"
110 #endif
111 #if INCLUDE_RTM_OPT
112 #include "runtime/rtmLocking.hpp"
113 #endif
114 #if INCLUDE_JFR
115 #include "jfr/jfr.hpp"
116 #endif
118 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
120 #ifdef DTRACE_ENABLED
122 // Only bother with this argument setup if dtrace is available
124 #ifndef USDT2
125 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
126 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
127 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
128 intptr_t, intptr_t, bool);
129 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
130 intptr_t, intptr_t, bool);
132 #define DTRACE_THREAD_PROBE(probe, javathread) \
133 { \
134 ResourceMark rm(this); \
135 int len = 0; \
136 const char* name = (javathread)->get_thread_name(); \
137 len = strlen(name); \
138 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
139 name, len, \
140 java_lang_Thread::thread_id((javathread)->threadObj()), \
141 (javathread)->osthread()->thread_id(), \
142 java_lang_Thread::is_daemon((javathread)->threadObj())); \
143 }
145 #else /* USDT2 */
147 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
148 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
150 #define DTRACE_THREAD_PROBE(probe, javathread) \
151 { \
152 ResourceMark rm(this); \
153 int len = 0; \
154 const char* name = (javathread)->get_thread_name(); \
155 len = strlen(name); \
156 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
157 (char *) name, len, \
158 java_lang_Thread::thread_id((javathread)->threadObj()), \
159 (uintptr_t) (javathread)->osthread()->thread_id(), \
160 java_lang_Thread::is_daemon((javathread)->threadObj())); \
161 }
163 #endif /* USDT2 */
165 #else // ndef DTRACE_ENABLED
167 #define DTRACE_THREAD_PROBE(probe, javathread)
169 #endif // ndef DTRACE_ENABLED
172 // Class hierarchy
173 // - Thread
174 // - VMThread
175 // - WatcherThread
176 // - ConcurrentMarkSweepThread
177 // - JavaThread
178 // - CompilerThread
180 // ======= Thread ========
181 // Support for forcing alignment of thread objects for biased locking
182 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
183 if (UseBiasedLocking) {
184 const int alignment = markOopDesc::biased_lock_alignment;
185 size_t aligned_size = size + (alignment - sizeof(intptr_t));
186 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
187 : AllocateHeap(aligned_size, flags, CURRENT_PC,
188 AllocFailStrategy::RETURN_NULL);
189 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
190 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
191 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
192 "JavaThread alignment code overflowed allocated storage");
193 if (TraceBiasedLocking) {
194 if (aligned_addr != real_malloc_addr)
195 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
196 real_malloc_addr, aligned_addr);
197 }
198 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
199 return aligned_addr;
200 } else {
201 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
202 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
203 }
204 }
206 void Thread::operator delete(void* p) {
207 if (UseBiasedLocking) {
208 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
209 FreeHeap(real_malloc_addr, mtThread);
210 } else {
211 FreeHeap(p, mtThread);
212 }
213 }
216 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
217 // JavaThread
220 Thread::Thread() {
221 // stack and get_thread
222 set_stack_base(NULL);
223 set_stack_size(0);
224 set_self_raw_id(0);
225 set_lgrp_id(-1);
227 // allocated data structures
228 set_osthread(NULL);
229 set_resource_area(new (mtThread)ResourceArea());
230 DEBUG_ONLY(_current_resource_mark = NULL;)
231 set_handle_area(new (mtThread) HandleArea(NULL));
232 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
233 set_active_handles(NULL);
234 set_free_handle_block(NULL);
235 set_last_handle_mark(NULL);
237 // This initial value ==> never claimed.
238 _oops_do_parity = 0;
240 _metadata_on_stack_buffer = NULL;
242 // the handle mark links itself to last_handle_mark
243 new HandleMark(this);
245 // plain initialization
246 debug_only(_owned_locks = NULL;)
247 debug_only(_allow_allocation_count = 0;)
248 NOT_PRODUCT(_allow_safepoint_count = 0;)
249 NOT_PRODUCT(_skip_gcalot = false;)
250 _jvmti_env_iteration_count = 0;
251 set_allocated_bytes(0);
252 _vm_operation_started_count = 0;
253 _vm_operation_completed_count = 0;
254 _current_pending_monitor = NULL;
255 _current_pending_monitor_is_from_java = true;
256 _current_waiting_monitor = NULL;
257 _num_nested_signal = 0;
258 omFreeList = NULL ;
259 omFreeCount = 0 ;
260 omFreeProvision = 32 ;
261 omInUseList = NULL ;
262 omInUseCount = 0 ;
264 #ifdef ASSERT
265 _visited_for_critical_count = false;
266 #endif
268 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
269 _suspend_flags = 0;
271 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
272 _hashStateX = os::random() ;
273 _hashStateY = 842502087 ;
274 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
275 _hashStateW = 273326509 ;
277 _OnTrap = 0 ;
278 _schedctl = NULL ;
279 _Stalled = 0 ;
280 _TypeTag = 0x2BAD ;
282 // Many of the following fields are effectively final - immutable
283 // Note that nascent threads can't use the Native Monitor-Mutex
284 // construct until the _MutexEvent is initialized ...
285 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
286 // we might instead use a stack of ParkEvents that we could provision on-demand.
287 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
288 // and ::Release()
289 _ParkEvent = ParkEvent::Allocate (this) ;
290 _SleepEvent = ParkEvent::Allocate (this) ;
291 _MutexEvent = ParkEvent::Allocate (this) ;
292 _MuxEvent = ParkEvent::Allocate (this) ;
294 #ifdef CHECK_UNHANDLED_OOPS
295 if (CheckUnhandledOops) {
296 _unhandled_oops = new UnhandledOops(this);
297 }
298 #endif // CHECK_UNHANDLED_OOPS
299 #ifdef ASSERT
300 if (UseBiasedLocking) {
301 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
302 assert(this == _real_malloc_address ||
303 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
304 "bug in forced alignment of thread objects");
305 }
306 #endif /* ASSERT */
307 }
309 void Thread::initialize_thread_local_storage() {
310 // Note: Make sure this method only calls
311 // non-blocking operations. Otherwise, it might not work
312 // with the thread-startup/safepoint interaction.
314 // During Java thread startup, safepoint code should allow this
315 // method to complete because it may need to allocate memory to
316 // store information for the new thread.
318 // initialize structure dependent on thread local storage
319 ThreadLocalStorage::set_thread(this);
320 }
322 void Thread::record_stack_base_and_size() {
323 set_stack_base(os::current_stack_base());
324 set_stack_size(os::current_stack_size());
325 if (is_Java_thread()) {
326 ((JavaThread*) this)->set_stack_overflow_limit();
327 }
328 // CR 7190089: on Solaris, primordial thread's stack is adjusted
329 // in initialize_thread(). Without the adjustment, stack size is
330 // incorrect if stack is set to unlimited (ulimit -s unlimited).
331 // So far, only Solaris has real implementation of initialize_thread().
332 //
333 // set up any platform-specific state.
334 os::initialize_thread(this);
336 #if INCLUDE_NMT
337 // record thread's native stack, stack grows downward
338 address stack_low_addr = stack_base() - stack_size();
339 MemTracker::record_thread_stack(stack_low_addr, stack_size());
340 #endif // INCLUDE_NMT
341 }
344 Thread::~Thread() {
345 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
346 ObjectSynchronizer::omFlush (this) ;
348 JFR_ONLY(Jfr::on_thread_destruct(this);)
350 // stack_base can be NULL if the thread is never started or exited before
351 // record_stack_base_and_size called. Although, we would like to ensure
352 // that all started threads do call record_stack_base_and_size(), there is
353 // not proper way to enforce that.
354 #if INCLUDE_NMT
355 if (_stack_base != NULL) {
356 address low_stack_addr = stack_base() - stack_size();
357 MemTracker::release_thread_stack(low_stack_addr, stack_size());
358 #ifdef ASSERT
359 set_stack_base(NULL);
360 #endif
361 }
362 #endif // INCLUDE_NMT
364 // deallocate data structures
365 delete resource_area();
366 // since the handle marks are using the handle area, we have to deallocated the root
367 // handle mark before deallocating the thread's handle area,
368 assert(last_handle_mark() != NULL, "check we have an element");
369 delete last_handle_mark();
370 assert(last_handle_mark() == NULL, "check we have reached the end");
372 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
373 // We NULL out the fields for good hygiene.
374 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
375 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
376 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
377 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
379 delete handle_area();
380 delete metadata_handles();
382 // osthread() can be NULL, if creation of thread failed.
383 if (osthread() != NULL) os::free_thread(osthread());
385 delete _SR_lock;
387 // clear thread local storage if the Thread is deleting itself
388 if (this == Thread::current()) {
389 ThreadLocalStorage::set_thread(NULL);
390 } else {
391 // In the case where we're not the current thread, invalidate all the
392 // caches in case some code tries to get the current thread or the
393 // thread that was destroyed, and gets stale information.
394 ThreadLocalStorage::invalidate_all();
395 }
396 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
397 }
399 // NOTE: dummy function for assertion purpose.
400 void Thread::run() {
401 ShouldNotReachHere();
402 }
404 #ifdef ASSERT
405 // Private method to check for dangling thread pointer
406 void check_for_dangling_thread_pointer(Thread *thread) {
407 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
408 "possibility of dangling Thread pointer");
409 }
410 #endif
413 #ifndef PRODUCT
414 // Tracing method for basic thread operations
415 void Thread::trace(const char* msg, const Thread* const thread) {
416 if (!TraceThreadEvents) return;
417 ResourceMark rm;
418 ThreadCritical tc;
419 const char *name = "non-Java thread";
420 int prio = -1;
421 if (thread->is_Java_thread()
422 && !thread->is_Compiler_thread()) {
423 // The Threads_lock must be held to get information about
424 // this thread but may not be in some situations when
425 // tracing thread events.
426 bool release_Threads_lock = false;
427 if (!Threads_lock->owned_by_self()) {
428 Threads_lock->lock();
429 release_Threads_lock = true;
430 }
431 JavaThread* jt = (JavaThread *)thread;
432 name = (char *)jt->get_thread_name();
433 oop thread_oop = jt->threadObj();
434 if (thread_oop != NULL) {
435 prio = java_lang_Thread::priority(thread_oop);
436 }
437 if (release_Threads_lock) {
438 Threads_lock->unlock();
439 }
440 }
441 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
442 }
443 #endif
446 ThreadPriority Thread::get_priority(const Thread* const thread) {
447 trace("get priority", thread);
448 ThreadPriority priority;
449 // Can return an error!
450 (void)os::get_priority(thread, priority);
451 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
452 return priority;
453 }
455 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
456 trace("set priority", thread);
457 debug_only(check_for_dangling_thread_pointer(thread);)
458 // Can return an error!
459 (void)os::set_priority(thread, priority);
460 }
463 void Thread::start(Thread* thread) {
464 trace("start", thread);
465 // Start is different from resume in that its safety is guaranteed by context or
466 // being called from a Java method synchronized on the Thread object.
467 if (!DisableStartThread) {
468 if (thread->is_Java_thread()) {
469 // Initialize the thread state to RUNNABLE before starting this thread.
470 // Can not set it after the thread started because we do not know the
471 // exact thread state at that time. It could be in MONITOR_WAIT or
472 // in SLEEPING or some other state.
473 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
474 java_lang_Thread::RUNNABLE);
475 }
476 os::start_thread(thread);
477 }
478 }
480 // Enqueue a VM_Operation to do the job for us - sometime later
481 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
482 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
483 VMThread::execute(vm_stop);
484 }
487 //
488 // Check if an external suspend request has completed (or has been
489 // cancelled). Returns true if the thread is externally suspended and
490 // false otherwise.
491 //
492 // The bits parameter returns information about the code path through
493 // the routine. Useful for debugging:
494 //
495 // set in is_ext_suspend_completed():
496 // 0x00000001 - routine was entered
497 // 0x00000010 - routine return false at end
498 // 0x00000100 - thread exited (return false)
499 // 0x00000200 - suspend request cancelled (return false)
500 // 0x00000400 - thread suspended (return true)
501 // 0x00001000 - thread is in a suspend equivalent state (return true)
502 // 0x00002000 - thread is native and walkable (return true)
503 // 0x00004000 - thread is native_trans and walkable (needed retry)
504 //
505 // set in wait_for_ext_suspend_completion():
506 // 0x00010000 - routine was entered
507 // 0x00020000 - suspend request cancelled before loop (return false)
508 // 0x00040000 - thread suspended before loop (return true)
509 // 0x00080000 - suspend request cancelled in loop (return false)
510 // 0x00100000 - thread suspended in loop (return true)
511 // 0x00200000 - suspend not completed during retry loop (return false)
512 //
514 // Helper class for tracing suspend wait debug bits.
515 //
516 // 0x00000100 indicates that the target thread exited before it could
517 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
518 // 0x00080000 each indicate a cancelled suspend request so they don't
519 // count as wait failures either.
520 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
522 class TraceSuspendDebugBits : public StackObj {
523 private:
524 JavaThread * jt;
525 bool is_wait;
526 bool called_by_wait; // meaningful when !is_wait
527 uint32_t * bits;
529 public:
530 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
531 uint32_t *_bits) {
532 jt = _jt;
533 is_wait = _is_wait;
534 called_by_wait = _called_by_wait;
535 bits = _bits;
536 }
538 ~TraceSuspendDebugBits() {
539 if (!is_wait) {
540 #if 1
541 // By default, don't trace bits for is_ext_suspend_completed() calls.
542 // That trace is very chatty.
543 return;
544 #else
545 if (!called_by_wait) {
546 // If tracing for is_ext_suspend_completed() is enabled, then only
547 // trace calls to it from wait_for_ext_suspend_completion()
548 return;
549 }
550 #endif
551 }
553 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
554 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
555 MutexLocker ml(Threads_lock); // needed for get_thread_name()
556 ResourceMark rm;
558 tty->print_cr(
559 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
560 jt->get_thread_name(), *bits);
562 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
563 }
564 }
565 }
566 };
567 #undef DEBUG_FALSE_BITS
570 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
571 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
573 bool did_trans_retry = false; // only do thread_in_native_trans retry once
574 bool do_trans_retry; // flag to force the retry
576 *bits |= 0x00000001;
578 do {
579 do_trans_retry = false;
581 if (is_exiting()) {
582 // Thread is in the process of exiting. This is always checked
583 // first to reduce the risk of dereferencing a freed JavaThread.
584 *bits |= 0x00000100;
585 return false;
586 }
588 if (!is_external_suspend()) {
589 // Suspend request is cancelled. This is always checked before
590 // is_ext_suspended() to reduce the risk of a rogue resume
591 // confusing the thread that made the suspend request.
592 *bits |= 0x00000200;
593 return false;
594 }
596 if (is_ext_suspended()) {
597 // thread is suspended
598 *bits |= 0x00000400;
599 return true;
600 }
602 // Now that we no longer do hard suspends of threads running
603 // native code, the target thread can be changing thread state
604 // while we are in this routine:
605 //
606 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
607 //
608 // We save a copy of the thread state as observed at this moment
609 // and make our decision about suspend completeness based on the
610 // copy. This closes the race where the thread state is seen as
611 // _thread_in_native_trans in the if-thread_blocked check, but is
612 // seen as _thread_blocked in if-thread_in_native_trans check.
613 JavaThreadState save_state = thread_state();
615 if (save_state == _thread_blocked && is_suspend_equivalent()) {
616 // If the thread's state is _thread_blocked and this blocking
617 // condition is known to be equivalent to a suspend, then we can
618 // consider the thread to be externally suspended. This means that
619 // the code that sets _thread_blocked has been modified to do
620 // self-suspension if the blocking condition releases. We also
621 // used to check for CONDVAR_WAIT here, but that is now covered by
622 // the _thread_blocked with self-suspension check.
623 //
624 // Return true since we wouldn't be here unless there was still an
625 // external suspend request.
626 *bits |= 0x00001000;
627 return true;
628 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
629 // Threads running native code will self-suspend on native==>VM/Java
630 // transitions. If its stack is walkable (should always be the case
631 // unless this function is called before the actual java_suspend()
632 // call), then the wait is done.
633 *bits |= 0x00002000;
634 return true;
635 } else if (!called_by_wait && !did_trans_retry &&
636 save_state == _thread_in_native_trans &&
637 frame_anchor()->walkable()) {
638 // The thread is transitioning from thread_in_native to another
639 // thread state. check_safepoint_and_suspend_for_native_trans()
640 // will force the thread to self-suspend. If it hasn't gotten
641 // there yet we may have caught the thread in-between the native
642 // code check above and the self-suspend. Lucky us. If we were
643 // called by wait_for_ext_suspend_completion(), then it
644 // will be doing the retries so we don't have to.
645 //
646 // Since we use the saved thread state in the if-statement above,
647 // there is a chance that the thread has already transitioned to
648 // _thread_blocked by the time we get here. In that case, we will
649 // make a single unnecessary pass through the logic below. This
650 // doesn't hurt anything since we still do the trans retry.
652 *bits |= 0x00004000;
654 // Once the thread leaves thread_in_native_trans for another
655 // thread state, we break out of this retry loop. We shouldn't
656 // need this flag to prevent us from getting back here, but
657 // sometimes paranoia is good.
658 did_trans_retry = true;
660 // We wait for the thread to transition to a more usable state.
661 for (int i = 1; i <= SuspendRetryCount; i++) {
662 // We used to do an "os::yield_all(i)" call here with the intention
663 // that yielding would increase on each retry. However, the parameter
664 // is ignored on Linux which means the yield didn't scale up. Waiting
665 // on the SR_lock below provides a much more predictable scale up for
666 // the delay. It also provides a simple/direct point to check for any
667 // safepoint requests from the VMThread
669 // temporarily drops SR_lock while doing wait with safepoint check
670 // (if we're a JavaThread - the WatcherThread can also call this)
671 // and increase delay with each retry
672 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
674 // check the actual thread state instead of what we saved above
675 if (thread_state() != _thread_in_native_trans) {
676 // the thread has transitioned to another thread state so
677 // try all the checks (except this one) one more time.
678 do_trans_retry = true;
679 break;
680 }
681 } // end retry loop
684 }
685 } while (do_trans_retry);
687 *bits |= 0x00000010;
688 return false;
689 }
691 //
692 // Wait for an external suspend request to complete (or be cancelled).
693 // Returns true if the thread is externally suspended and false otherwise.
694 //
695 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
696 uint32_t *bits) {
697 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
698 false /* !called_by_wait */, bits);
700 // local flag copies to minimize SR_lock hold time
701 bool is_suspended;
702 bool pending;
703 uint32_t reset_bits;
705 // set a marker so is_ext_suspend_completed() knows we are the caller
706 *bits |= 0x00010000;
708 // We use reset_bits to reinitialize the bits value at the top of
709 // each retry loop. This allows the caller to make use of any
710 // unused bits for their own marking purposes.
711 reset_bits = *bits;
713 {
714 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
715 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
716 delay, bits);
717 pending = is_external_suspend();
718 }
719 // must release SR_lock to allow suspension to complete
721 if (!pending) {
722 // A cancelled suspend request is the only false return from
723 // is_ext_suspend_completed() that keeps us from entering the
724 // retry loop.
725 *bits |= 0x00020000;
726 return false;
727 }
729 if (is_suspended) {
730 *bits |= 0x00040000;
731 return true;
732 }
734 for (int i = 1; i <= retries; i++) {
735 *bits = reset_bits; // reinit to only track last retry
737 // We used to do an "os::yield_all(i)" call here with the intention
738 // that yielding would increase on each retry. However, the parameter
739 // is ignored on Linux which means the yield didn't scale up. Waiting
740 // on the SR_lock below provides a much more predictable scale up for
741 // the delay. It also provides a simple/direct point to check for any
742 // safepoint requests from the VMThread
744 {
745 MutexLocker ml(SR_lock());
746 // wait with safepoint check (if we're a JavaThread - the WatcherThread
747 // can also call this) and increase delay with each retry
748 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
750 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
751 delay, bits);
753 // It is possible for the external suspend request to be cancelled
754 // (by a resume) before the actual suspend operation is completed.
755 // Refresh our local copy to see if we still need to wait.
756 pending = is_external_suspend();
757 }
759 if (!pending) {
760 // A cancelled suspend request is the only false return from
761 // is_ext_suspend_completed() that keeps us from staying in the
762 // retry loop.
763 *bits |= 0x00080000;
764 return false;
765 }
767 if (is_suspended) {
768 *bits |= 0x00100000;
769 return true;
770 }
771 } // end retry loop
773 // thread did not suspend after all our retries
774 *bits |= 0x00200000;
775 return false;
776 }
778 #ifndef PRODUCT
779 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
781 // This should not need to be atomic as the only way for simultaneous
782 // updates is via interrupts. Even then this should be rare or non-existant
783 // and we don't care that much anyway.
785 int index = _jmp_ring_index;
786 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
787 _jmp_ring[index]._target = (intptr_t) target;
788 _jmp_ring[index]._instruction = (intptr_t) instr;
789 _jmp_ring[index]._file = file;
790 _jmp_ring[index]._line = line;
791 }
792 #endif /* PRODUCT */
794 // Called by flat profiler
795 // Callers have already called wait_for_ext_suspend_completion
796 // The assertion for that is currently too complex to put here:
797 bool JavaThread::profile_last_Java_frame(frame* _fr) {
798 bool gotframe = false;
799 // self suspension saves needed state.
800 if (has_last_Java_frame() && _anchor.walkable()) {
801 *_fr = pd_last_frame();
802 gotframe = true;
803 }
804 return gotframe;
805 }
807 void Thread::interrupt(Thread* thread) {
808 trace("interrupt", thread);
809 debug_only(check_for_dangling_thread_pointer(thread);)
810 os::interrupt(thread);
811 }
813 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
814 trace("is_interrupted", thread);
815 debug_only(check_for_dangling_thread_pointer(thread);)
816 // Note: If clear_interrupted==false, this simply fetches and
817 // returns the value of the field osthread()->interrupted().
818 return os::is_interrupted(thread, clear_interrupted);
819 }
822 // GC Support
823 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
824 jint thread_parity = _oops_do_parity;
825 if (thread_parity != strong_roots_parity) {
826 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
827 if (res == thread_parity) {
828 return true;
829 } else {
830 guarantee(res == strong_roots_parity, "Or else what?");
831 assert(SharedHeap::heap()->workers()->active_workers() > 0,
832 "Should only fail when parallel.");
833 return false;
834 }
835 }
836 assert(SharedHeap::heap()->workers()->active_workers() > 0,
837 "Should only fail when parallel.");
838 return false;
839 }
841 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
842 active_handles()->oops_do(f);
843 // Do oop for ThreadShadow
844 f->do_oop((oop*)&_pending_exception);
845 handle_area()->oops_do(f);
846 }
848 void Thread::nmethods_do(CodeBlobClosure* cf) {
849 // no nmethods in a generic thread...
850 }
852 void Thread::metadata_do(void f(Metadata*)) {
853 if (metadata_handles() != NULL) {
854 for (int i = 0; i< metadata_handles()->length(); i++) {
855 f(metadata_handles()->at(i));
856 }
857 }
858 }
860 void Thread::print_on(outputStream* st) const {
861 // get_priority assumes osthread initialized
862 if (osthread() != NULL) {
863 int os_prio;
864 if (os::get_native_priority(this, &os_prio) == OS_OK) {
865 st->print("os_prio=%d ", os_prio);
866 }
867 st->print("tid=" INTPTR_FORMAT " ", this);
868 ext().print_on(st);
869 osthread()->print_on(st);
870 }
871 debug_only(if (WizardMode) print_owned_locks_on(st);)
872 }
874 // Thread::print_on_error() is called by fatal error handler. Don't use
875 // any lock or allocate memory.
876 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
877 if (is_VM_thread()) st->print("VMThread");
878 else if (is_Compiler_thread()) st->print("CompilerThread");
879 else if (is_Java_thread()) st->print("JavaThread");
880 else if (is_GC_task_thread()) st->print("GCTaskThread");
881 else if (is_Watcher_thread()) st->print("WatcherThread");
882 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
883 else st->print("Thread");
885 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
886 _stack_base - _stack_size, _stack_base);
888 if (osthread()) {
889 st->print(" [id=%d]", osthread()->thread_id());
890 }
891 }
893 #ifdef ASSERT
894 void Thread::print_owned_locks_on(outputStream* st) const {
895 Monitor *cur = _owned_locks;
896 if (cur == NULL) {
897 st->print(" (no locks) ");
898 } else {
899 st->print_cr(" Locks owned:");
900 while(cur) {
901 cur->print_on(st);
902 cur = cur->next();
903 }
904 }
905 }
907 static int ref_use_count = 0;
909 bool Thread::owns_locks_but_compiled_lock() const {
910 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
911 if (cur != Compile_lock) return true;
912 }
913 return false;
914 }
917 #endif
919 #ifndef PRODUCT
921 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
922 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
923 // no threads which allow_vm_block's are held
924 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
925 // Check if current thread is allowed to block at a safepoint
926 if (!(_allow_safepoint_count == 0))
927 fatal("Possible safepoint reached by thread that does not allow it");
928 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
929 fatal("LEAF method calling lock?");
930 }
932 #ifdef ASSERT
933 if (potential_vm_operation && is_Java_thread()
934 && !Universe::is_bootstrapping()) {
935 // Make sure we do not hold any locks that the VM thread also uses.
936 // This could potentially lead to deadlocks
937 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
938 // Threads_lock is special, since the safepoint synchronization will not start before this is
939 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
940 // since it is used to transfer control between JavaThreads and the VMThread
941 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
942 if ( (cur->allow_vm_block() &&
943 cur != Threads_lock &&
944 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
945 cur != VMOperationRequest_lock &&
946 cur != VMOperationQueue_lock) ||
947 cur->rank() == Mutex::special) {
948 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
949 }
950 }
951 }
953 if (GCALotAtAllSafepoints) {
954 // We could enter a safepoint here and thus have a gc
955 InterfaceSupport::check_gc_alot();
956 }
957 #endif
958 }
959 #endif
961 bool Thread::is_in_stack(address adr) const {
962 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
963 address end = os::current_stack_pointer();
964 // Allow non Java threads to call this without stack_base
965 if (_stack_base == NULL) return true;
966 if (stack_base() >= adr && adr >= end) return true;
968 return false;
969 }
972 bool Thread::is_in_usable_stack(address adr) const {
973 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
974 size_t usable_stack_size = _stack_size - stack_guard_size;
976 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
977 }
980 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
981 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
982 // used for compilation in the future. If that change is made, the need for these methods
983 // should be revisited, and they should be removed if possible.
985 bool Thread::is_lock_owned(address adr) const {
986 return on_local_stack(adr);
987 }
989 bool Thread::set_as_starting_thread() {
990 // NOTE: this must be called inside the main thread.
991 return os::create_main_thread((JavaThread*)this);
992 }
994 static void initialize_class(Symbol* class_name, TRAPS) {
995 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
996 InstanceKlass::cast(klass)->initialize(CHECK);
997 }
1000 // Creates the initial ThreadGroup
1001 static Handle create_initial_thread_group(TRAPS) {
1002 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1003 instanceKlassHandle klass (THREAD, k);
1005 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1006 {
1007 JavaValue result(T_VOID);
1008 JavaCalls::call_special(&result,
1009 system_instance,
1010 klass,
1011 vmSymbols::object_initializer_name(),
1012 vmSymbols::void_method_signature(),
1013 CHECK_NH);
1014 }
1015 Universe::set_system_thread_group(system_instance());
1017 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1018 {
1019 JavaValue result(T_VOID);
1020 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1021 JavaCalls::call_special(&result,
1022 main_instance,
1023 klass,
1024 vmSymbols::object_initializer_name(),
1025 vmSymbols::threadgroup_string_void_signature(),
1026 system_instance,
1027 string,
1028 CHECK_NH);
1029 }
1030 return main_instance;
1031 }
1033 // Creates the initial Thread
1034 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1035 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1036 instanceKlassHandle klass (THREAD, k);
1037 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1039 java_lang_Thread::set_thread(thread_oop(), thread);
1040 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1041 thread->set_threadObj(thread_oop());
1043 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1045 JavaValue result(T_VOID);
1046 JavaCalls::call_special(&result, thread_oop,
1047 klass,
1048 vmSymbols::object_initializer_name(),
1049 vmSymbols::threadgroup_string_void_signature(),
1050 thread_group,
1051 string,
1052 CHECK_NULL);
1053 return thread_oop();
1054 }
1056 static void call_initializeSystemClass(TRAPS) {
1057 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1058 instanceKlassHandle klass (THREAD, k);
1060 JavaValue result(T_VOID);
1061 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1062 vmSymbols::void_method_signature(), CHECK);
1063 }
1065 char java_runtime_name[128] = "";
1066 char java_runtime_version[128] = "";
1068 // extract the JRE name from sun.misc.Version.java_runtime_name
1069 static const char* get_java_runtime_name(TRAPS) {
1070 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1071 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1072 fieldDescriptor fd;
1073 bool found = k != NULL &&
1074 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1075 vmSymbols::string_signature(), &fd);
1076 if (found) {
1077 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1078 if (name_oop == NULL)
1079 return NULL;
1080 const char* name = java_lang_String::as_utf8_string(name_oop,
1081 java_runtime_name,
1082 sizeof(java_runtime_name));
1083 return name;
1084 } else {
1085 return NULL;
1086 }
1087 }
1089 // extract the JRE version from sun.misc.Version.java_runtime_version
1090 static const char* get_java_runtime_version(TRAPS) {
1091 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1092 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1093 fieldDescriptor fd;
1094 bool found = k != NULL &&
1095 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1096 vmSymbols::string_signature(), &fd);
1097 if (found) {
1098 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1099 if (name_oop == NULL)
1100 return NULL;
1101 const char* name = java_lang_String::as_utf8_string(name_oop,
1102 java_runtime_version,
1103 sizeof(java_runtime_version));
1104 return name;
1105 } else {
1106 return NULL;
1107 }
1108 }
1110 // General purpose hook into Java code, run once when the VM is initialized.
1111 // The Java library method itself may be changed independently from the VM.
1112 static void call_postVMInitHook(TRAPS) {
1113 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1114 instanceKlassHandle klass (THREAD, k);
1115 if (klass.not_null()) {
1116 JavaValue result(T_VOID);
1117 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1118 vmSymbols::void_method_signature(),
1119 CHECK);
1120 }
1121 }
1123 static void reset_vm_info_property(TRAPS) {
1124 // the vm info string
1125 ResourceMark rm(THREAD);
1126 const char *vm_info = VM_Version::vm_info_string();
1128 // java.lang.System class
1129 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1130 instanceKlassHandle klass (THREAD, k);
1132 // setProperty arguments
1133 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1134 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1136 // return value
1137 JavaValue r(T_OBJECT);
1139 // public static String setProperty(String key, String value);
1140 JavaCalls::call_static(&r,
1141 klass,
1142 vmSymbols::setProperty_name(),
1143 vmSymbols::string_string_string_signature(),
1144 key_str,
1145 value_str,
1146 CHECK);
1147 }
1150 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1151 assert(thread_group.not_null(), "thread group should be specified");
1152 assert(threadObj() == NULL, "should only create Java thread object once");
1154 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1155 instanceKlassHandle klass (THREAD, k);
1156 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1158 java_lang_Thread::set_thread(thread_oop(), this);
1159 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1160 set_threadObj(thread_oop());
1162 JavaValue result(T_VOID);
1163 if (thread_name != NULL) {
1164 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1165 // Thread gets assigned specified name and null target
1166 JavaCalls::call_special(&result,
1167 thread_oop,
1168 klass,
1169 vmSymbols::object_initializer_name(),
1170 vmSymbols::threadgroup_string_void_signature(),
1171 thread_group, // Argument 1
1172 name, // Argument 2
1173 THREAD);
1174 } else {
1175 // Thread gets assigned name "Thread-nnn" and null target
1176 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1177 JavaCalls::call_special(&result,
1178 thread_oop,
1179 klass,
1180 vmSymbols::object_initializer_name(),
1181 vmSymbols::threadgroup_runnable_void_signature(),
1182 thread_group, // Argument 1
1183 Handle(), // Argument 2
1184 THREAD);
1185 }
1188 if (daemon) {
1189 java_lang_Thread::set_daemon(thread_oop());
1190 }
1192 if (HAS_PENDING_EXCEPTION) {
1193 return;
1194 }
1196 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1197 Handle threadObj(this, this->threadObj());
1199 JavaCalls::call_special(&result,
1200 thread_group,
1201 group,
1202 vmSymbols::add_method_name(),
1203 vmSymbols::thread_void_signature(),
1204 threadObj, // Arg 1
1205 THREAD);
1208 }
1210 // NamedThread -- non-JavaThread subclasses with multiple
1211 // uniquely named instances should derive from this.
1212 NamedThread::NamedThread() : Thread() {
1213 _name = NULL;
1214 _processed_thread = NULL;
1215 }
1217 NamedThread::~NamedThread() {
1218 if (_name != NULL) {
1219 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1220 _name = NULL;
1221 }
1222 }
1224 void NamedThread::set_name(const char* format, ...) {
1225 guarantee(_name == NULL, "Only get to set name once.");
1226 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1227 guarantee(_name != NULL, "alloc failure");
1228 va_list ap;
1229 va_start(ap, format);
1230 jio_vsnprintf(_name, max_name_len, format, ap);
1231 va_end(ap);
1232 }
1234 // ======= WatcherThread ========
1236 // The watcher thread exists to simulate timer interrupts. It should
1237 // be replaced by an abstraction over whatever native support for
1238 // timer interrupts exists on the platform.
1240 WatcherThread* WatcherThread::_watcher_thread = NULL;
1241 bool WatcherThread::_startable = false;
1242 volatile bool WatcherThread::_should_terminate = false;
1244 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1245 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1246 if (os::create_thread(this, os::watcher_thread)) {
1247 _watcher_thread = this;
1249 // Set the watcher thread to the highest OS priority which should not be
1250 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1251 // is created. The only normal thread using this priority is the reference
1252 // handler thread, which runs for very short intervals only.
1253 // If the VMThread's priority is not lower than the WatcherThread profiling
1254 // will be inaccurate.
1255 os::set_priority(this, MaxPriority);
1256 if (!DisableStartThread) {
1257 os::start_thread(this);
1258 }
1259 }
1260 }
1262 int WatcherThread::sleep() const {
1263 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1265 // remaining will be zero if there are no tasks,
1266 // causing the WatcherThread to sleep until a task is
1267 // enrolled
1268 int remaining = PeriodicTask::time_to_wait();
1269 int time_slept = 0;
1271 // we expect this to timeout - we only ever get unparked when
1272 // we should terminate or when a new task has been enrolled
1273 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1275 jlong time_before_loop = os::javaTimeNanos();
1277 for (;;) {
1278 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1279 jlong now = os::javaTimeNanos();
1281 if (remaining == 0) {
1282 // if we didn't have any tasks we could have waited for a long time
1283 // consider the time_slept zero and reset time_before_loop
1284 time_slept = 0;
1285 time_before_loop = now;
1286 } else {
1287 // need to recalulate since we might have new tasks in _tasks
1288 time_slept = (int) ((now - time_before_loop) / 1000000);
1289 }
1291 // Change to task list or spurious wakeup of some kind
1292 if (timedout || _should_terminate) {
1293 break;
1294 }
1296 remaining = PeriodicTask::time_to_wait();
1297 if (remaining == 0) {
1298 // Last task was just disenrolled so loop around and wait until
1299 // another task gets enrolled
1300 continue;
1301 }
1303 remaining -= time_slept;
1304 if (remaining <= 0)
1305 break;
1306 }
1308 return time_slept;
1309 }
1311 void WatcherThread::run() {
1312 assert(this == watcher_thread(), "just checking");
1314 this->record_stack_base_and_size();
1315 this->initialize_thread_local_storage();
1316 this->set_native_thread_name(this->name());
1317 this->set_active_handles(JNIHandleBlock::allocate_block());
1318 while(!_should_terminate) {
1319 assert(watcher_thread() == Thread::current(), "thread consistency check");
1320 assert(watcher_thread() == this, "thread consistency check");
1322 // Calculate how long it'll be until the next PeriodicTask work
1323 // should be done, and sleep that amount of time.
1324 int time_waited = sleep();
1326 if (is_error_reported()) {
1327 // A fatal error has happened, the error handler(VMError::report_and_die)
1328 // should abort JVM after creating an error log file. However in some
1329 // rare cases, the error handler itself might deadlock. Here we try to
1330 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1331 //
1332 // This code is in WatcherThread because WatcherThread wakes up
1333 // periodically so the fatal error handler doesn't need to do anything;
1334 // also because the WatcherThread is less likely to crash than other
1335 // threads.
1337 for (;;) {
1338 if (!ShowMessageBoxOnError
1339 && (OnError == NULL || OnError[0] == '\0')
1340 && Arguments::abort_hook() == NULL) {
1341 os::sleep(this, 2 * 60 * 1000, false);
1342 fdStream err(defaultStream::output_fd());
1343 err.print_raw_cr("# [ timer expired, abort... ]");
1344 // skip atexit/vm_exit/vm_abort hooks
1345 os::die();
1346 }
1348 // Wake up 5 seconds later, the fatal handler may reset OnError or
1349 // ShowMessageBoxOnError when it is ready to abort.
1350 os::sleep(this, 5 * 1000, false);
1351 }
1352 }
1354 PeriodicTask::real_time_tick(time_waited);
1355 }
1357 // Signal that it is terminated
1358 {
1359 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1360 _watcher_thread = NULL;
1361 Terminator_lock->notify();
1362 }
1364 // Thread destructor usually does this..
1365 ThreadLocalStorage::set_thread(NULL);
1366 }
1368 void WatcherThread::start() {
1369 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1371 if (watcher_thread() == NULL && _startable) {
1372 _should_terminate = false;
1373 // Create the single instance of WatcherThread
1374 new WatcherThread();
1375 }
1376 }
1378 void WatcherThread::make_startable() {
1379 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1380 _startable = true;
1381 }
1383 void WatcherThread::stop() {
1384 {
1385 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1386 _should_terminate = true;
1387 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1389 WatcherThread* watcher = watcher_thread();
1390 if (watcher != NULL)
1391 watcher->unpark();
1392 }
1394 // it is ok to take late safepoints here, if needed
1395 MutexLocker mu(Terminator_lock);
1397 while(watcher_thread() != NULL) {
1398 // This wait should make safepoint checks, wait without a timeout,
1399 // and wait as a suspend-equivalent condition.
1400 //
1401 // Note: If the FlatProfiler is running, then this thread is waiting
1402 // for the WatcherThread to terminate and the WatcherThread, via the
1403 // FlatProfiler task, is waiting for the external suspend request on
1404 // this thread to complete. wait_for_ext_suspend_completion() will
1405 // eventually timeout, but that takes time. Making this wait a
1406 // suspend-equivalent condition solves that timeout problem.
1407 //
1408 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1409 Mutex::_as_suspend_equivalent_flag);
1410 }
1411 }
1413 void WatcherThread::unpark() {
1414 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1415 PeriodicTask_lock->notify();
1416 }
1418 void WatcherThread::print_on(outputStream* st) const {
1419 st->print("\"%s\" ", name());
1420 Thread::print_on(st);
1421 st->cr();
1422 }
1424 // ======= JavaThread ========
1426 // A JavaThread is a normal Java thread
1428 void JavaThread::initialize() {
1429 // Initialize fields
1431 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1432 set_claimed_par_id(UINT_MAX);
1434 set_saved_exception_pc(NULL);
1435 set_threadObj(NULL);
1436 _anchor.clear();
1437 set_entry_point(NULL);
1438 set_jni_functions(jni_functions());
1439 set_callee_target(NULL);
1440 set_vm_result(NULL);
1441 set_vm_result_2(NULL);
1442 set_vframe_array_head(NULL);
1443 set_vframe_array_last(NULL);
1444 set_deferred_locals(NULL);
1445 set_deopt_mark(NULL);
1446 set_deopt_nmethod(NULL);
1447 clear_must_deopt_id();
1448 set_monitor_chunks(NULL);
1449 set_next(NULL);
1450 set_thread_state(_thread_new);
1451 _terminated = _not_terminated;
1452 _privileged_stack_top = NULL;
1453 _array_for_gc = NULL;
1454 _suspend_equivalent = false;
1455 _in_deopt_handler = 0;
1456 _doing_unsafe_access = false;
1457 _stack_guard_state = stack_guard_unused;
1458 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1459 _exception_pc = 0;
1460 _exception_handler_pc = 0;
1461 _is_method_handle_return = 0;
1462 _jvmti_thread_state= NULL;
1463 _should_post_on_exceptions_flag = JNI_FALSE;
1464 _jvmti_get_loaded_classes_closure = NULL;
1465 _interp_only_mode = 0;
1466 _special_runtime_exit_condition = _no_async_condition;
1467 _pending_async_exception = NULL;
1468 _thread_stat = NULL;
1469 _thread_stat = new ThreadStatistics();
1470 _blocked_on_compilation = false;
1471 _jni_active_critical = 0;
1472 _pending_jni_exception_check_fn = NULL;
1473 _do_not_unlock_if_synchronized = false;
1474 _cached_monitor_info = NULL;
1475 _parker = Parker::Allocate(this) ;
1477 #ifndef PRODUCT
1478 _jmp_ring_index = 0;
1479 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1480 record_jump(NULL, NULL, NULL, 0);
1481 }
1482 #endif /* PRODUCT */
1484 set_thread_profiler(NULL);
1485 if (FlatProfiler::is_active()) {
1486 // This is where we would decide to either give each thread it's own profiler
1487 // or use one global one from FlatProfiler,
1488 // or up to some count of the number of profiled threads, etc.
1489 ThreadProfiler* pp = new ThreadProfiler();
1490 pp->engage();
1491 set_thread_profiler(pp);
1492 }
1494 // Setup safepoint state info for this thread
1495 ThreadSafepointState::create(this);
1497 debug_only(_java_call_counter = 0);
1499 // JVMTI PopFrame support
1500 _popframe_condition = popframe_inactive;
1501 _popframe_preserved_args = NULL;
1502 _popframe_preserved_args_size = 0;
1503 _frames_to_pop_failed_realloc = 0;
1505 pd_initialize();
1506 }
1508 #if INCLUDE_ALL_GCS
1509 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1510 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1511 #endif // INCLUDE_ALL_GCS
1513 JavaThread::JavaThread(bool is_attaching_via_jni) :
1514 Thread()
1515 #if INCLUDE_ALL_GCS
1516 , _satb_mark_queue(&_satb_mark_queue_set),
1517 _dirty_card_queue(&_dirty_card_queue_set)
1518 #endif // INCLUDE_ALL_GCS
1519 {
1520 initialize();
1521 if (is_attaching_via_jni) {
1522 _jni_attach_state = _attaching_via_jni;
1523 } else {
1524 _jni_attach_state = _not_attaching_via_jni;
1525 }
1526 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1527 }
1529 bool JavaThread::reguard_stack(address cur_sp) {
1530 if (_stack_guard_state != stack_guard_yellow_disabled) {
1531 return true; // Stack already guarded or guard pages not needed.
1532 }
1534 if (register_stack_overflow()) {
1535 // For those architectures which have separate register and
1536 // memory stacks, we must check the register stack to see if
1537 // it has overflowed.
1538 return false;
1539 }
1541 // Java code never executes within the yellow zone: the latter is only
1542 // there to provoke an exception during stack banging. If java code
1543 // is executing there, either StackShadowPages should be larger, or
1544 // some exception code in c1, c2 or the interpreter isn't unwinding
1545 // when it should.
1546 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1548 enable_stack_yellow_zone();
1549 return true;
1550 }
1552 bool JavaThread::reguard_stack(void) {
1553 return reguard_stack(os::current_stack_pointer());
1554 }
1557 void JavaThread::block_if_vm_exited() {
1558 if (_terminated == _vm_exited) {
1559 // _vm_exited is set at safepoint, and Threads_lock is never released
1560 // we will block here forever
1561 Threads_lock->lock_without_safepoint_check();
1562 ShouldNotReachHere();
1563 }
1564 }
1567 // Remove this ifdef when C1 is ported to the compiler interface.
1568 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1570 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1571 Thread()
1572 #if INCLUDE_ALL_GCS
1573 , _satb_mark_queue(&_satb_mark_queue_set),
1574 _dirty_card_queue(&_dirty_card_queue_set)
1575 #endif // INCLUDE_ALL_GCS
1576 {
1577 if (TraceThreadEvents) {
1578 tty->print_cr("creating thread %p", this);
1579 }
1580 initialize();
1581 _jni_attach_state = _not_attaching_via_jni;
1582 set_entry_point(entry_point);
1583 // Create the native thread itself.
1584 // %note runtime_23
1585 os::ThreadType thr_type = os::java_thread;
1586 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1587 os::java_thread;
1588 os::create_thread(this, thr_type, stack_sz);
1589 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1590 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1591 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1592 // the exception consists of creating the exception object & initializing it, initialization
1593 // will leave the VM via a JavaCall and then all locks must be unlocked).
1594 //
1595 // The thread is still suspended when we reach here. Thread must be explicit started
1596 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1597 // by calling Threads:add. The reason why this is not done here, is because the thread
1598 // object must be fully initialized (take a look at JVM_Start)
1599 }
1601 JavaThread::~JavaThread() {
1602 if (TraceThreadEvents) {
1603 tty->print_cr("terminate thread %p", this);
1604 }
1606 // JSR166 -- return the parker to the free list
1607 Parker::Release(_parker);
1608 _parker = NULL ;
1610 // Free any remaining previous UnrollBlock
1611 vframeArray* old_array = vframe_array_last();
1613 if (old_array != NULL) {
1614 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1615 old_array->set_unroll_block(NULL);
1616 delete old_info;
1617 delete old_array;
1618 }
1620 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1621 if (deferred != NULL) {
1622 // This can only happen if thread is destroyed before deoptimization occurs.
1623 assert(deferred->length() != 0, "empty array!");
1624 do {
1625 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1626 deferred->remove_at(0);
1627 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1628 delete dlv;
1629 } while (deferred->length() != 0);
1630 delete deferred;
1631 }
1633 // All Java related clean up happens in exit
1634 ThreadSafepointState::destroy(this);
1635 if (_thread_profiler != NULL) delete _thread_profiler;
1636 if (_thread_stat != NULL) delete _thread_stat;
1637 }
1640 // The first routine called by a new Java thread
1641 void JavaThread::run() {
1642 // initialize thread-local alloc buffer related fields
1643 this->initialize_tlab();
1645 // used to test validitity of stack trace backs
1646 this->record_base_of_stack_pointer();
1648 // Record real stack base and size.
1649 this->record_stack_base_and_size();
1651 // Initialize thread local storage; set before calling MutexLocker
1652 this->initialize_thread_local_storage();
1654 this->create_stack_guard_pages();
1656 this->cache_global_variables();
1658 // Thread is now sufficient initialized to be handled by the safepoint code as being
1659 // in the VM. Change thread state from _thread_new to _thread_in_vm
1660 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1662 assert(JavaThread::current() == this, "sanity check");
1663 assert(!Thread::current()->owns_locks(), "sanity check");
1665 DTRACE_THREAD_PROBE(start, this);
1667 // This operation might block. We call that after all safepoint checks for a new thread has
1668 // been completed.
1669 this->set_active_handles(JNIHandleBlock::allocate_block());
1671 if (JvmtiExport::should_post_thread_life()) {
1672 JvmtiExport::post_thread_start(this);
1673 }
1675 EventThreadStart event;
1676 if (event.should_commit()) {
1677 event.set_thread(JFR_THREAD_ID(this));
1678 event.commit();
1679 }
1681 // We call another function to do the rest so we are sure that the stack addresses used
1682 // from there will be lower than the stack base just computed
1683 thread_main_inner();
1685 // Note, thread is no longer valid at this point!
1686 }
1689 void JavaThread::thread_main_inner() {
1690 assert(JavaThread::current() == this, "sanity check");
1691 assert(this->threadObj() != NULL, "just checking");
1693 // Execute thread entry point unless this thread has a pending exception
1694 // or has been stopped before starting.
1695 // Note: Due to JVM_StopThread we can have pending exceptions already!
1696 if (!this->has_pending_exception() &&
1697 !java_lang_Thread::is_stillborn(this->threadObj())) {
1698 {
1699 ResourceMark rm(this);
1700 this->set_native_thread_name(this->get_thread_name());
1701 }
1702 HandleMark hm(this);
1703 this->entry_point()(this, this);
1704 }
1706 DTRACE_THREAD_PROBE(stop, this);
1708 this->exit(false);
1709 delete this;
1710 }
1713 static void ensure_join(JavaThread* thread) {
1714 // We do not need to grap the Threads_lock, since we are operating on ourself.
1715 Handle threadObj(thread, thread->threadObj());
1716 assert(threadObj.not_null(), "java thread object must exist");
1717 ObjectLocker lock(threadObj, thread);
1718 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1719 thread->clear_pending_exception();
1720 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1721 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1722 // Clear the native thread instance - this makes isAlive return false and allows the join()
1723 // to complete once we've done the notify_all below
1724 java_lang_Thread::set_thread(threadObj(), NULL);
1725 lock.notify_all(thread);
1726 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1727 thread->clear_pending_exception();
1728 }
1731 // For any new cleanup additions, please check to see if they need to be applied to
1732 // cleanup_failed_attach_current_thread as well.
1733 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1734 assert(this == JavaThread::current(), "thread consistency check");
1736 HandleMark hm(this);
1737 Handle uncaught_exception(this, this->pending_exception());
1738 this->clear_pending_exception();
1739 Handle threadObj(this, this->threadObj());
1740 assert(threadObj.not_null(), "Java thread object should be created");
1742 if (get_thread_profiler() != NULL) {
1743 get_thread_profiler()->disengage();
1744 ResourceMark rm;
1745 get_thread_profiler()->print(get_thread_name());
1746 }
1749 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1750 {
1751 EXCEPTION_MARK;
1753 CLEAR_PENDING_EXCEPTION;
1754 }
1755 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1756 // has to be fixed by a runtime query method
1757 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1758 // JSR-166: change call from from ThreadGroup.uncaughtException to
1759 // java.lang.Thread.dispatchUncaughtException
1760 if (uncaught_exception.not_null()) {
1761 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1762 {
1763 EXCEPTION_MARK;
1764 // Check if the method Thread.dispatchUncaughtException() exists. If so
1765 // call it. Otherwise we have an older library without the JSR-166 changes,
1766 // so call ThreadGroup.uncaughtException()
1767 KlassHandle recvrKlass(THREAD, threadObj->klass());
1768 CallInfo callinfo;
1769 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1770 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1771 vmSymbols::dispatchUncaughtException_name(),
1772 vmSymbols::throwable_void_signature(),
1773 KlassHandle(), false, false, THREAD);
1774 CLEAR_PENDING_EXCEPTION;
1775 methodHandle method = callinfo.selected_method();
1776 if (method.not_null()) {
1777 JavaValue result(T_VOID);
1778 JavaCalls::call_virtual(&result,
1779 threadObj, thread_klass,
1780 vmSymbols::dispatchUncaughtException_name(),
1781 vmSymbols::throwable_void_signature(),
1782 uncaught_exception,
1783 THREAD);
1784 } else {
1785 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1786 JavaValue result(T_VOID);
1787 JavaCalls::call_virtual(&result,
1788 group, thread_group,
1789 vmSymbols::uncaughtException_name(),
1790 vmSymbols::thread_throwable_void_signature(),
1791 threadObj, // Arg 1
1792 uncaught_exception, // Arg 2
1793 THREAD);
1794 }
1795 if (HAS_PENDING_EXCEPTION) {
1796 ResourceMark rm(this);
1797 jio_fprintf(defaultStream::error_stream(),
1798 "\nException: %s thrown from the UncaughtExceptionHandler"
1799 " in thread \"%s\"\n",
1800 pending_exception()->klass()->external_name(),
1801 get_thread_name());
1802 CLEAR_PENDING_EXCEPTION;
1803 }
1804 }
1805 }
1807 // Called before the java thread exit since we want to read info
1808 // from java_lang_Thread object
1809 EventThreadEnd event;
1810 if (event.should_commit()) {
1811 event.set_thread(JFR_THREAD_ID(this));
1812 event.commit();
1813 }
1815 // Call after last event on thread
1816 JFR_ONLY(Jfr::on_thread_exit(this);)
1818 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1819 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1820 // is deprecated anyhow.
1821 if (!is_Compiler_thread()) {
1822 int count = 3;
1823 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1824 EXCEPTION_MARK;
1825 JavaValue result(T_VOID);
1826 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1827 JavaCalls::call_virtual(&result,
1828 threadObj, thread_klass,
1829 vmSymbols::exit_method_name(),
1830 vmSymbols::void_method_signature(),
1831 THREAD);
1832 CLEAR_PENDING_EXCEPTION;
1833 }
1834 }
1835 // notify JVMTI
1836 if (JvmtiExport::should_post_thread_life()) {
1837 JvmtiExport::post_thread_end(this);
1838 }
1840 // We have notified the agents that we are exiting, before we go on,
1841 // we must check for a pending external suspend request and honor it
1842 // in order to not surprise the thread that made the suspend request.
1843 while (true) {
1844 {
1845 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1846 if (!is_external_suspend()) {
1847 set_terminated(_thread_exiting);
1848 ThreadService::current_thread_exiting(this);
1849 break;
1850 }
1851 // Implied else:
1852 // Things get a little tricky here. We have a pending external
1853 // suspend request, but we are holding the SR_lock so we
1854 // can't just self-suspend. So we temporarily drop the lock
1855 // and then self-suspend.
1856 }
1858 ThreadBlockInVM tbivm(this);
1859 java_suspend_self();
1861 // We're done with this suspend request, but we have to loop around
1862 // and check again. Eventually we will get SR_lock without a pending
1863 // external suspend request and will be able to mark ourselves as
1864 // exiting.
1865 }
1866 // no more external suspends are allowed at this point
1867 } else {
1868 // before_exit() has already posted JVMTI THREAD_END events
1869 }
1871 // Notify waiters on thread object. This has to be done after exit() is called
1872 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1873 // group should have the destroyed bit set before waiters are notified).
1874 ensure_join(this);
1875 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1877 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1878 // held by this thread must be released. A detach operation must only
1879 // get here if there are no Java frames on the stack. Therefore, any
1880 // owned monitors at this point MUST be JNI-acquired monitors which are
1881 // pre-inflated and in the monitor cache.
1882 //
1883 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1884 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1885 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1886 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1887 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1888 }
1890 // These things needs to be done while we are still a Java Thread. Make sure that thread
1891 // is in a consistent state, in case GC happens
1892 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1894 if (active_handles() != NULL) {
1895 JNIHandleBlock* block = active_handles();
1896 set_active_handles(NULL);
1897 JNIHandleBlock::release_block(block);
1898 }
1900 if (free_handle_block() != NULL) {
1901 JNIHandleBlock* block = free_handle_block();
1902 set_free_handle_block(NULL);
1903 JNIHandleBlock::release_block(block);
1904 }
1906 // These have to be removed while this is still a valid thread.
1907 remove_stack_guard_pages();
1909 if (UseTLAB) {
1910 tlab().make_parsable(true); // retire TLAB
1911 }
1913 if (JvmtiEnv::environments_might_exist()) {
1914 JvmtiExport::cleanup_thread(this);
1915 }
1917 // We must flush any deferred card marks before removing a thread from
1918 // the list of active threads.
1919 Universe::heap()->flush_deferred_store_barrier(this);
1920 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1922 #if INCLUDE_ALL_GCS
1923 // We must flush the G1-related buffers before removing a thread
1924 // from the list of active threads. We must do this after any deferred
1925 // card marks have been flushed (above) so that any entries that are
1926 // added to the thread's dirty card queue as a result are not lost.
1927 if (UseG1GC) {
1928 flush_barrier_queues();
1929 }
1930 #endif // INCLUDE_ALL_GCS
1932 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1933 Threads::remove(this);
1934 }
1936 #if INCLUDE_ALL_GCS
1937 // Flush G1-related queues.
1938 void JavaThread::flush_barrier_queues() {
1939 satb_mark_queue().flush();
1940 dirty_card_queue().flush();
1941 }
1943 void JavaThread::initialize_queues() {
1944 assert(!SafepointSynchronize::is_at_safepoint(),
1945 "we should not be at a safepoint");
1947 ObjPtrQueue& satb_queue = satb_mark_queue();
1948 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1949 // The SATB queue should have been constructed with its active
1950 // field set to false.
1951 assert(!satb_queue.is_active(), "SATB queue should not be active");
1952 assert(satb_queue.is_empty(), "SATB queue should be empty");
1953 // If we are creating the thread during a marking cycle, we should
1954 // set the active field of the SATB queue to true.
1955 if (satb_queue_set.is_active()) {
1956 satb_queue.set_active(true);
1957 }
1959 DirtyCardQueue& dirty_queue = dirty_card_queue();
1960 // The dirty card queue should have been constructed with its
1961 // active field set to true.
1962 assert(dirty_queue.is_active(), "dirty card queue should be active");
1963 }
1964 #endif // INCLUDE_ALL_GCS
1966 void JavaThread::cleanup_failed_attach_current_thread() {
1967 if (get_thread_profiler() != NULL) {
1968 get_thread_profiler()->disengage();
1969 ResourceMark rm;
1970 get_thread_profiler()->print(get_thread_name());
1971 }
1973 if (active_handles() != NULL) {
1974 JNIHandleBlock* block = active_handles();
1975 set_active_handles(NULL);
1976 JNIHandleBlock::release_block(block);
1977 }
1979 if (free_handle_block() != NULL) {
1980 JNIHandleBlock* block = free_handle_block();
1981 set_free_handle_block(NULL);
1982 JNIHandleBlock::release_block(block);
1983 }
1985 // These have to be removed while this is still a valid thread.
1986 remove_stack_guard_pages();
1988 if (UseTLAB) {
1989 tlab().make_parsable(true); // retire TLAB, if any
1990 }
1992 #if INCLUDE_ALL_GCS
1993 if (UseG1GC) {
1994 flush_barrier_queues();
1995 }
1996 #endif // INCLUDE_ALL_GCS
1998 Threads::remove(this);
1999 delete this;
2000 }
2005 JavaThread* JavaThread::active() {
2006 Thread* thread = ThreadLocalStorage::thread();
2007 assert(thread != NULL, "just checking");
2008 if (thread->is_Java_thread()) {
2009 return (JavaThread*) thread;
2010 } else {
2011 assert(thread->is_VM_thread(), "this must be a vm thread");
2012 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2013 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2014 assert(ret->is_Java_thread(), "must be a Java thread");
2015 return ret;
2016 }
2017 }
2019 bool JavaThread::is_lock_owned(address adr) const {
2020 if (Thread::is_lock_owned(adr)) return true;
2022 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2023 if (chunk->contains(adr)) return true;
2024 }
2026 return false;
2027 }
2030 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2031 chunk->set_next(monitor_chunks());
2032 set_monitor_chunks(chunk);
2033 }
2035 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2036 guarantee(monitor_chunks() != NULL, "must be non empty");
2037 if (monitor_chunks() == chunk) {
2038 set_monitor_chunks(chunk->next());
2039 } else {
2040 MonitorChunk* prev = monitor_chunks();
2041 while (prev->next() != chunk) prev = prev->next();
2042 prev->set_next(chunk->next());
2043 }
2044 }
2046 // JVM support.
2048 // Note: this function shouldn't block if it's called in
2049 // _thread_in_native_trans state (such as from
2050 // check_special_condition_for_native_trans()).
2051 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2053 if (has_last_Java_frame() && has_async_condition()) {
2054 // If we are at a polling page safepoint (not a poll return)
2055 // then we must defer async exception because live registers
2056 // will be clobbered by the exception path. Poll return is
2057 // ok because the call we a returning from already collides
2058 // with exception handling registers and so there is no issue.
2059 // (The exception handling path kills call result registers but
2060 // this is ok since the exception kills the result anyway).
2062 if (is_at_poll_safepoint()) {
2063 // if the code we are returning to has deoptimized we must defer
2064 // the exception otherwise live registers get clobbered on the
2065 // exception path before deoptimization is able to retrieve them.
2066 //
2067 RegisterMap map(this, false);
2068 frame caller_fr = last_frame().sender(&map);
2069 assert(caller_fr.is_compiled_frame(), "what?");
2070 if (caller_fr.is_deoptimized_frame()) {
2071 if (TraceExceptions) {
2072 ResourceMark rm;
2073 tty->print_cr("deferred async exception at compiled safepoint");
2074 }
2075 return;
2076 }
2077 }
2078 }
2080 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2081 if (condition == _no_async_condition) {
2082 // Conditions have changed since has_special_runtime_exit_condition()
2083 // was called:
2084 // - if we were here only because of an external suspend request,
2085 // then that was taken care of above (or cancelled) so we are done
2086 // - if we were here because of another async request, then it has
2087 // been cleared between the has_special_runtime_exit_condition()
2088 // and now so again we are done
2089 return;
2090 }
2092 // Check for pending async. exception
2093 if (_pending_async_exception != NULL) {
2094 // Only overwrite an already pending exception, if it is not a threadDeath.
2095 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2097 // We cannot call Exceptions::_throw(...) here because we cannot block
2098 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2100 if (TraceExceptions) {
2101 ResourceMark rm;
2102 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2103 if (has_last_Java_frame() ) {
2104 frame f = last_frame();
2105 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2106 }
2107 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2108 }
2109 _pending_async_exception = NULL;
2110 clear_has_async_exception();
2111 }
2112 }
2114 if (check_unsafe_error &&
2115 condition == _async_unsafe_access_error && !has_pending_exception()) {
2116 condition = _no_async_condition; // done
2117 switch (thread_state()) {
2118 case _thread_in_vm:
2119 {
2120 JavaThread* THREAD = this;
2121 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2122 }
2123 case _thread_in_native:
2124 {
2125 ThreadInVMfromNative tiv(this);
2126 JavaThread* THREAD = this;
2127 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2128 }
2129 case _thread_in_Java:
2130 {
2131 ThreadInVMfromJava tiv(this);
2132 JavaThread* THREAD = this;
2133 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2134 }
2135 default:
2136 ShouldNotReachHere();
2137 }
2138 }
2140 assert(condition == _no_async_condition || has_pending_exception() ||
2141 (!check_unsafe_error && condition == _async_unsafe_access_error),
2142 "must have handled the async condition, if no exception");
2143 }
2145 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2146 //
2147 // Check for pending external suspend. Internal suspend requests do
2148 // not use handle_special_runtime_exit_condition().
2149 // If JNIEnv proxies are allowed, don't self-suspend if the target
2150 // thread is not the current thread. In older versions of jdbx, jdbx
2151 // threads could call into the VM with another thread's JNIEnv so we
2152 // can be here operating on behalf of a suspended thread (4432884).
2153 bool do_self_suspend = is_external_suspend_with_lock();
2154 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2155 //
2156 // Because thread is external suspended the safepoint code will count
2157 // thread as at a safepoint. This can be odd because we can be here
2158 // as _thread_in_Java which would normally transition to _thread_blocked
2159 // at a safepoint. We would like to mark the thread as _thread_blocked
2160 // before calling java_suspend_self like all other callers of it but
2161 // we must then observe proper safepoint protocol. (We can't leave
2162 // _thread_blocked with a safepoint in progress). However we can be
2163 // here as _thread_in_native_trans so we can't use a normal transition
2164 // constructor/destructor pair because they assert on that type of
2165 // transition. We could do something like:
2166 //
2167 // JavaThreadState state = thread_state();
2168 // set_thread_state(_thread_in_vm);
2169 // {
2170 // ThreadBlockInVM tbivm(this);
2171 // java_suspend_self()
2172 // }
2173 // set_thread_state(_thread_in_vm_trans);
2174 // if (safepoint) block;
2175 // set_thread_state(state);
2176 //
2177 // but that is pretty messy. Instead we just go with the way the
2178 // code has worked before and note that this is the only path to
2179 // java_suspend_self that doesn't put the thread in _thread_blocked
2180 // mode.
2182 frame_anchor()->make_walkable(this);
2183 java_suspend_self();
2185 // We might be here for reasons in addition to the self-suspend request
2186 // so check for other async requests.
2187 }
2189 if (check_asyncs) {
2190 check_and_handle_async_exceptions();
2191 }
2193 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2194 }
2196 void JavaThread::send_thread_stop(oop java_throwable) {
2197 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2198 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2199 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2201 // Do not throw asynchronous exceptions against the compiler thread
2202 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2203 if (is_Compiler_thread()) return;
2205 {
2206 // Actually throw the Throwable against the target Thread - however
2207 // only if there is no thread death exception installed already.
2208 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2209 // If the topmost frame is a runtime stub, then we are calling into
2210 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2211 // must deoptimize the caller before continuing, as the compiled exception handler table
2212 // may not be valid
2213 if (has_last_Java_frame()) {
2214 frame f = last_frame();
2215 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2216 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2217 RegisterMap reg_map(this, UseBiasedLocking);
2218 frame compiled_frame = f.sender(®_map);
2219 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2220 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2221 }
2222 }
2223 }
2225 // Set async. pending exception in thread.
2226 set_pending_async_exception(java_throwable);
2228 if (TraceExceptions) {
2229 ResourceMark rm;
2230 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2231 }
2232 // for AbortVMOnException flag
2233 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2234 }
2235 }
2238 // Interrupt thread so it will wake up from a potential wait()
2239 Thread::interrupt(this);
2240 }
2242 // External suspension mechanism.
2243 //
2244 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2245 // to any VM_locks and it is at a transition
2246 // Self-suspension will happen on the transition out of the vm.
2247 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2248 //
2249 // Guarantees on return:
2250 // + Target thread will not execute any new bytecode (that's why we need to
2251 // force a safepoint)
2252 // + Target thread will not enter any new monitors
2253 //
2254 void JavaThread::java_suspend() {
2255 { MutexLocker mu(Threads_lock);
2256 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2257 return;
2258 }
2259 }
2261 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2262 if (!is_external_suspend()) {
2263 // a racing resume has cancelled us; bail out now
2264 return;
2265 }
2267 // suspend is done
2268 uint32_t debug_bits = 0;
2269 // Warning: is_ext_suspend_completed() may temporarily drop the
2270 // SR_lock to allow the thread to reach a stable thread state if
2271 // it is currently in a transient thread state.
2272 if (is_ext_suspend_completed(false /* !called_by_wait */,
2273 SuspendRetryDelay, &debug_bits) ) {
2274 return;
2275 }
2276 }
2278 VM_ForceSafepoint vm_suspend;
2279 VMThread::execute(&vm_suspend);
2280 }
2282 // Part II of external suspension.
2283 // A JavaThread self suspends when it detects a pending external suspend
2284 // request. This is usually on transitions. It is also done in places
2285 // where continuing to the next transition would surprise the caller,
2286 // e.g., monitor entry.
2287 //
2288 // Returns the number of times that the thread self-suspended.
2289 //
2290 // Note: DO NOT call java_suspend_self() when you just want to block current
2291 // thread. java_suspend_self() is the second stage of cooperative
2292 // suspension for external suspend requests and should only be used
2293 // to complete an external suspend request.
2294 //
2295 int JavaThread::java_suspend_self() {
2296 int ret = 0;
2298 // we are in the process of exiting so don't suspend
2299 if (is_exiting()) {
2300 clear_external_suspend();
2301 return ret;
2302 }
2304 assert(_anchor.walkable() ||
2305 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2306 "must have walkable stack");
2308 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2310 assert(!this->is_ext_suspended(),
2311 "a thread trying to self-suspend should not already be suspended");
2313 if (this->is_suspend_equivalent()) {
2314 // If we are self-suspending as a result of the lifting of a
2315 // suspend equivalent condition, then the suspend_equivalent
2316 // flag is not cleared until we set the ext_suspended flag so
2317 // that wait_for_ext_suspend_completion() returns consistent
2318 // results.
2319 this->clear_suspend_equivalent();
2320 }
2322 // A racing resume may have cancelled us before we grabbed SR_lock
2323 // above. Or another external suspend request could be waiting for us
2324 // by the time we return from SR_lock()->wait(). The thread
2325 // that requested the suspension may already be trying to walk our
2326 // stack and if we return now, we can change the stack out from under
2327 // it. This would be a "bad thing (TM)" and cause the stack walker
2328 // to crash. We stay self-suspended until there are no more pending
2329 // external suspend requests.
2330 while (is_external_suspend()) {
2331 ret++;
2332 this->set_ext_suspended();
2334 // _ext_suspended flag is cleared by java_resume()
2335 while (is_ext_suspended()) {
2336 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2337 }
2338 }
2340 return ret;
2341 }
2343 #ifdef ASSERT
2344 // verify the JavaThread has not yet been published in the Threads::list, and
2345 // hence doesn't need protection from concurrent access at this stage
2346 void JavaThread::verify_not_published() {
2347 if (!Threads_lock->owned_by_self()) {
2348 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2349 assert( !Threads::includes(this),
2350 "java thread shouldn't have been published yet!");
2351 }
2352 else {
2353 assert( !Threads::includes(this),
2354 "java thread shouldn't have been published yet!");
2355 }
2356 }
2357 #endif
2359 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2360 // progress or when _suspend_flags is non-zero.
2361 // Current thread needs to self-suspend if there is a suspend request and/or
2362 // block if a safepoint is in progress.
2363 // Async exception ISN'T checked.
2364 // Note only the ThreadInVMfromNative transition can call this function
2365 // directly and when thread state is _thread_in_native_trans
2366 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2367 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2369 JavaThread *curJT = JavaThread::current();
2370 bool do_self_suspend = thread->is_external_suspend();
2372 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2374 // If JNIEnv proxies are allowed, don't self-suspend if the target
2375 // thread is not the current thread. In older versions of jdbx, jdbx
2376 // threads could call into the VM with another thread's JNIEnv so we
2377 // can be here operating on behalf of a suspended thread (4432884).
2378 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2379 JavaThreadState state = thread->thread_state();
2381 // We mark this thread_blocked state as a suspend-equivalent so
2382 // that a caller to is_ext_suspend_completed() won't be confused.
2383 // The suspend-equivalent state is cleared by java_suspend_self().
2384 thread->set_suspend_equivalent();
2386 // If the safepoint code sees the _thread_in_native_trans state, it will
2387 // wait until the thread changes to other thread state. There is no
2388 // guarantee on how soon we can obtain the SR_lock and complete the
2389 // self-suspend request. It would be a bad idea to let safepoint wait for
2390 // too long. Temporarily change the state to _thread_blocked to
2391 // let the VM thread know that this thread is ready for GC. The problem
2392 // of changing thread state is that safepoint could happen just after
2393 // java_suspend_self() returns after being resumed, and VM thread will
2394 // see the _thread_blocked state. We must check for safepoint
2395 // after restoring the state and make sure we won't leave while a safepoint
2396 // is in progress.
2397 thread->set_thread_state(_thread_blocked);
2398 thread->java_suspend_self();
2399 thread->set_thread_state(state);
2400 // Make sure new state is seen by VM thread
2401 if (os::is_MP()) {
2402 if (UseMembar) {
2403 // Force a fence between the write above and read below
2404 OrderAccess::fence();
2405 } else {
2406 // Must use this rather than serialization page in particular on Windows
2407 InterfaceSupport::serialize_memory(thread);
2408 }
2409 }
2410 }
2412 if (SafepointSynchronize::do_call_back()) {
2413 // If we are safepointing, then block the caller which may not be
2414 // the same as the target thread (see above).
2415 SafepointSynchronize::block(curJT);
2416 }
2418 if (thread->is_deopt_suspend()) {
2419 thread->clear_deopt_suspend();
2420 RegisterMap map(thread, false);
2421 frame f = thread->last_frame();
2422 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2423 f = f.sender(&map);
2424 }
2425 if (f.id() == thread->must_deopt_id()) {
2426 thread->clear_must_deopt_id();
2427 f.deoptimize(thread);
2428 } else {
2429 fatal("missed deoptimization!");
2430 }
2431 }
2433 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2434 }
2436 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2437 // progress or when _suspend_flags is non-zero.
2438 // Current thread needs to self-suspend if there is a suspend request and/or
2439 // block if a safepoint is in progress.
2440 // Also check for pending async exception (not including unsafe access error).
2441 // Note only the native==>VM/Java barriers can call this function and when
2442 // thread state is _thread_in_native_trans.
2443 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2444 check_safepoint_and_suspend_for_native_trans(thread);
2446 if (thread->has_async_exception()) {
2447 // We are in _thread_in_native_trans state, don't handle unsafe
2448 // access error since that may block.
2449 thread->check_and_handle_async_exceptions(false);
2450 }
2451 }
2453 // This is a variant of the normal
2454 // check_special_condition_for_native_trans with slightly different
2455 // semantics for use by critical native wrappers. It does all the
2456 // normal checks but also performs the transition back into
2457 // thread_in_Java state. This is required so that critical natives
2458 // can potentially block and perform a GC if they are the last thread
2459 // exiting the GC_locker.
2460 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2461 check_special_condition_for_native_trans(thread);
2463 // Finish the transition
2464 thread->set_thread_state(_thread_in_Java);
2466 if (thread->do_critical_native_unlock()) {
2467 ThreadInVMfromJavaNoAsyncException tiv(thread);
2468 GC_locker::unlock_critical(thread);
2469 thread->clear_critical_native_unlock();
2470 }
2471 }
2473 // We need to guarantee the Threads_lock here, since resumes are not
2474 // allowed during safepoint synchronization
2475 // Can only resume from an external suspension
2476 void JavaThread::java_resume() {
2477 assert_locked_or_safepoint(Threads_lock);
2479 // Sanity check: thread is gone, has started exiting or the thread
2480 // was not externally suspended.
2481 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2482 return;
2483 }
2485 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2487 clear_external_suspend();
2489 if (is_ext_suspended()) {
2490 clear_ext_suspended();
2491 SR_lock()->notify_all();
2492 }
2493 }
2495 void JavaThread::create_stack_guard_pages() {
2496 if (!os::uses_stack_guard_pages() ||
2497 _stack_guard_state != stack_guard_unused ||
2498 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2499 if (TraceThreadEvents) {
2500 tty->print_cr("Stack guard page creation for thread "
2501 UINTX_FORMAT " disabled", os::current_thread_id());
2502 }
2503 return;
2504 }
2505 address low_addr = stack_base() - stack_size();
2506 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2508 int allocate = os::allocate_stack_guard_pages();
2509 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2511 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2512 warning("Attempt to allocate stack guard pages failed.");
2513 return;
2514 }
2516 if (os::guard_memory((char *) low_addr, len)) {
2517 _stack_guard_state = stack_guard_enabled;
2518 } else {
2519 warning("Attempt to protect stack guard pages failed.");
2520 if (os::uncommit_memory((char *) low_addr, len)) {
2521 warning("Attempt to deallocate stack guard pages failed.");
2522 }
2523 }
2524 }
2526 void JavaThread::remove_stack_guard_pages() {
2527 assert(Thread::current() == this, "from different thread");
2528 if (_stack_guard_state == stack_guard_unused) return;
2529 address low_addr = stack_base() - stack_size();
2530 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2532 if (os::allocate_stack_guard_pages()) {
2533 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2534 _stack_guard_state = stack_guard_unused;
2535 } else {
2536 warning("Attempt to deallocate stack guard pages failed.");
2537 }
2538 } else {
2539 if (_stack_guard_state == stack_guard_unused) return;
2540 if (os::unguard_memory((char *) low_addr, len)) {
2541 _stack_guard_state = stack_guard_unused;
2542 } else {
2543 warning("Attempt to unprotect stack guard pages failed.");
2544 }
2545 }
2546 }
2548 void JavaThread::enable_stack_yellow_zone() {
2549 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2550 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2552 // The base notation is from the stacks point of view, growing downward.
2553 // We need to adjust it to work correctly with guard_memory()
2554 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2556 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2557 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2559 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2560 _stack_guard_state = stack_guard_enabled;
2561 } else {
2562 warning("Attempt to guard stack yellow zone failed.");
2563 }
2564 enable_register_stack_guard();
2565 }
2567 void JavaThread::disable_stack_yellow_zone() {
2568 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2569 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2571 // Simply return if called for a thread that does not use guard pages.
2572 if (_stack_guard_state == stack_guard_unused) return;
2574 // The base notation is from the stacks point of view, growing downward.
2575 // We need to adjust it to work correctly with guard_memory()
2576 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2578 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2579 _stack_guard_state = stack_guard_yellow_disabled;
2580 } else {
2581 warning("Attempt to unguard stack yellow zone failed.");
2582 }
2583 disable_register_stack_guard();
2584 }
2586 void JavaThread::enable_stack_red_zone() {
2587 // The base notation is from the stacks point of view, growing downward.
2588 // We need to adjust it to work correctly with guard_memory()
2589 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2590 address base = stack_red_zone_base() - stack_red_zone_size();
2592 guarantee(base < stack_base(),"Error calculating stack red zone");
2593 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2595 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2596 warning("Attempt to guard stack red zone failed.");
2597 }
2598 }
2600 void JavaThread::disable_stack_red_zone() {
2601 // The base notation is from the stacks point of view, growing downward.
2602 // We need to adjust it to work correctly with guard_memory()
2603 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2604 address base = stack_red_zone_base() - stack_red_zone_size();
2605 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2606 warning("Attempt to unguard stack red zone failed.");
2607 }
2608 }
2610 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2611 // ignore is there is no stack
2612 if (!has_last_Java_frame()) return;
2613 // traverse the stack frames. Starts from top frame.
2614 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2615 frame* fr = fst.current();
2616 f(fr, fst.register_map());
2617 }
2618 }
2621 #ifndef PRODUCT
2622 // Deoptimization
2623 // Function for testing deoptimization
2624 void JavaThread::deoptimize() {
2625 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2626 StackFrameStream fst(this, UseBiasedLocking);
2627 bool deopt = false; // Dump stack only if a deopt actually happens.
2628 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2629 // Iterate over all frames in the thread and deoptimize
2630 for(; !fst.is_done(); fst.next()) {
2631 if(fst.current()->can_be_deoptimized()) {
2633 if (only_at) {
2634 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2635 // consists of comma or carriage return separated numbers so
2636 // search for the current bci in that string.
2637 address pc = fst.current()->pc();
2638 nmethod* nm = (nmethod*) fst.current()->cb();
2639 ScopeDesc* sd = nm->scope_desc_at( pc);
2640 char buffer[8];
2641 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2642 size_t len = strlen(buffer);
2643 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2644 while (found != NULL) {
2645 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2646 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2647 // Check that the bci found is bracketed by terminators.
2648 break;
2649 }
2650 found = strstr(found + 1, buffer);
2651 }
2652 if (!found) {
2653 continue;
2654 }
2655 }
2657 if (DebugDeoptimization && !deopt) {
2658 deopt = true; // One-time only print before deopt
2659 tty->print_cr("[BEFORE Deoptimization]");
2660 trace_frames();
2661 trace_stack();
2662 }
2663 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2664 }
2665 }
2667 if (DebugDeoptimization && deopt) {
2668 tty->print_cr("[AFTER Deoptimization]");
2669 trace_frames();
2670 }
2671 }
2674 // Make zombies
2675 void JavaThread::make_zombies() {
2676 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2677 if (fst.current()->can_be_deoptimized()) {
2678 // it is a Java nmethod
2679 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2680 nm->make_not_entrant();
2681 }
2682 }
2683 }
2684 #endif // PRODUCT
2687 void JavaThread::deoptimized_wrt_marked_nmethods() {
2688 if (!has_last_Java_frame()) return;
2689 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2690 StackFrameStream fst(this, UseBiasedLocking);
2691 for(; !fst.is_done(); fst.next()) {
2692 if (fst.current()->should_be_deoptimized()) {
2693 if (LogCompilation && xtty != NULL) {
2694 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2695 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2696 this->name(), nm != NULL ? nm->compile_id() : -1);
2697 }
2699 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2700 }
2701 }
2702 }
2705 // GC support
2706 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2708 void JavaThread::gc_epilogue() {
2709 frames_do(frame_gc_epilogue);
2710 }
2713 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2715 void JavaThread::gc_prologue() {
2716 frames_do(frame_gc_prologue);
2717 }
2719 // If the caller is a NamedThread, then remember, in the current scope,
2720 // the given JavaThread in its _processed_thread field.
2721 class RememberProcessedThread: public StackObj {
2722 NamedThread* _cur_thr;
2723 public:
2724 RememberProcessedThread(JavaThread* jthr) {
2725 Thread* thread = Thread::current();
2726 if (thread->is_Named_thread()) {
2727 _cur_thr = (NamedThread *)thread;
2728 _cur_thr->set_processed_thread(jthr);
2729 } else {
2730 _cur_thr = NULL;
2731 }
2732 }
2734 ~RememberProcessedThread() {
2735 if (_cur_thr) {
2736 _cur_thr->set_processed_thread(NULL);
2737 }
2738 }
2739 };
2741 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2742 // Verify that the deferred card marks have been flushed.
2743 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2745 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2746 // since there may be more than one thread using each ThreadProfiler.
2748 // Traverse the GCHandles
2749 Thread::oops_do(f, cld_f, cf);
2751 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2752 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2754 if (has_last_Java_frame()) {
2755 // Record JavaThread to GC thread
2756 RememberProcessedThread rpt(this);
2758 // Traverse the privileged stack
2759 if (_privileged_stack_top != NULL) {
2760 _privileged_stack_top->oops_do(f);
2761 }
2763 // traverse the registered growable array
2764 if (_array_for_gc != NULL) {
2765 for (int index = 0; index < _array_for_gc->length(); index++) {
2766 f->do_oop(_array_for_gc->adr_at(index));
2767 }
2768 }
2770 // Traverse the monitor chunks
2771 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2772 chunk->oops_do(f);
2773 }
2775 // Traverse the execution stack
2776 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2777 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2778 }
2779 }
2781 // callee_target is never live across a gc point so NULL it here should
2782 // it still contain a methdOop.
2784 set_callee_target(NULL);
2786 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2787 // If we have deferred set_locals there might be oops waiting to be
2788 // written
2789 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2790 if (list != NULL) {
2791 for (int i = 0; i < list->length(); i++) {
2792 list->at(i)->oops_do(f);
2793 }
2794 }
2796 // Traverse instance variables at the end since the GC may be moving things
2797 // around using this function
2798 f->do_oop((oop*) &_threadObj);
2799 f->do_oop((oop*) &_vm_result);
2800 f->do_oop((oop*) &_exception_oop);
2801 f->do_oop((oop*) &_pending_async_exception);
2803 if (jvmti_thread_state() != NULL) {
2804 jvmti_thread_state()->oops_do(f);
2805 }
2806 }
2808 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2809 Thread::nmethods_do(cf); // (super method is a no-op)
2811 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2812 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2814 if (has_last_Java_frame()) {
2815 // Traverse the execution stack
2816 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2817 fst.current()->nmethods_do(cf);
2818 }
2819 }
2820 }
2822 void JavaThread::metadata_do(void f(Metadata*)) {
2823 Thread::metadata_do(f);
2824 if (has_last_Java_frame()) {
2825 // Traverse the execution stack to call f() on the methods in the stack
2826 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2827 fst.current()->metadata_do(f);
2828 }
2829 } else if (is_Compiler_thread()) {
2830 // need to walk ciMetadata in current compile tasks to keep alive.
2831 CompilerThread* ct = (CompilerThread*)this;
2832 if (ct->env() != NULL) {
2833 ct->env()->metadata_do(f);
2834 }
2835 }
2836 }
2838 // Printing
2839 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2840 switch (_thread_state) {
2841 case _thread_uninitialized: return "_thread_uninitialized";
2842 case _thread_new: return "_thread_new";
2843 case _thread_new_trans: return "_thread_new_trans";
2844 case _thread_in_native: return "_thread_in_native";
2845 case _thread_in_native_trans: return "_thread_in_native_trans";
2846 case _thread_in_vm: return "_thread_in_vm";
2847 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2848 case _thread_in_Java: return "_thread_in_Java";
2849 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2850 case _thread_blocked: return "_thread_blocked";
2851 case _thread_blocked_trans: return "_thread_blocked_trans";
2852 default: return "unknown thread state";
2853 }
2854 }
2856 #ifndef PRODUCT
2857 void JavaThread::print_thread_state_on(outputStream *st) const {
2858 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2859 };
2860 void JavaThread::print_thread_state() const {
2861 print_thread_state_on(tty);
2862 };
2863 #endif // PRODUCT
2865 // Called by Threads::print() for VM_PrintThreads operation
2866 void JavaThread::print_on(outputStream *st) const {
2867 st->print("\"%s\" ", get_thread_name());
2868 oop thread_oop = threadObj();
2869 if (thread_oop != NULL) {
2870 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2871 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2872 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2873 }
2874 Thread::print_on(st);
2875 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2876 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2877 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2878 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2879 }
2880 #ifndef PRODUCT
2881 print_thread_state_on(st);
2882 _safepoint_state->print_on(st);
2883 #endif // PRODUCT
2884 }
2886 // Called by fatal error handler. The difference between this and
2887 // JavaThread::print() is that we can't grab lock or allocate memory.
2888 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2889 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2890 oop thread_obj = threadObj();
2891 if (thread_obj != NULL) {
2892 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2893 }
2894 st->print(" [");
2895 st->print("%s", _get_thread_state_name(_thread_state));
2896 if (osthread()) {
2897 st->print(", id=%d", osthread()->thread_id());
2898 }
2899 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2900 _stack_base - _stack_size, _stack_base);
2901 st->print("]");
2902 return;
2903 }
2905 // Verification
2907 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2909 void JavaThread::verify() {
2910 // Verify oops in the thread.
2911 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2913 // Verify the stack frames.
2914 frames_do(frame_verify);
2915 }
2917 // CR 6300358 (sub-CR 2137150)
2918 // Most callers of this method assume that it can't return NULL but a
2919 // thread may not have a name whilst it is in the process of attaching to
2920 // the VM - see CR 6412693, and there are places where a JavaThread can be
2921 // seen prior to having it's threadObj set (eg JNI attaching threads and
2922 // if vm exit occurs during initialization). These cases can all be accounted
2923 // for such that this method never returns NULL.
2924 const char* JavaThread::get_thread_name() const {
2925 #ifdef ASSERT
2926 // early safepoints can hit while current thread does not yet have TLS
2927 if (!SafepointSynchronize::is_at_safepoint()) {
2928 Thread *cur = Thread::current();
2929 if (!(cur->is_Java_thread() && cur == this)) {
2930 // Current JavaThreads are allowed to get their own name without
2931 // the Threads_lock.
2932 assert_locked_or_safepoint(Threads_lock);
2933 }
2934 }
2935 #endif // ASSERT
2936 return get_thread_name_string();
2937 }
2939 // Returns a non-NULL representation of this thread's name, or a suitable
2940 // descriptive string if there is no set name
2941 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2942 const char* name_str;
2943 oop thread_obj = threadObj();
2944 if (thread_obj != NULL) {
2945 oop name = java_lang_Thread::name(thread_obj);
2946 if (name != NULL) {
2947 if (buf == NULL) {
2948 name_str = java_lang_String::as_utf8_string(name);
2949 }
2950 else {
2951 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2952 }
2953 }
2954 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2955 name_str = "<no-name - thread is attaching>";
2956 }
2957 else {
2958 name_str = Thread::name();
2959 }
2960 }
2961 else {
2962 name_str = Thread::name();
2963 }
2964 assert(name_str != NULL, "unexpected NULL thread name");
2965 return name_str;
2966 }
2969 const char* JavaThread::get_threadgroup_name() const {
2970 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2971 oop thread_obj = threadObj();
2972 if (thread_obj != NULL) {
2973 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2974 if (thread_group != NULL) {
2975 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2976 // ThreadGroup.name can be null
2977 if (name != NULL) {
2978 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2979 return str;
2980 }
2981 }
2982 }
2983 return NULL;
2984 }
2986 const char* JavaThread::get_parent_name() const {
2987 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2988 oop thread_obj = threadObj();
2989 if (thread_obj != NULL) {
2990 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2991 if (thread_group != NULL) {
2992 oop parent = java_lang_ThreadGroup::parent(thread_group);
2993 if (parent != NULL) {
2994 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2995 // ThreadGroup.name can be null
2996 if (name != NULL) {
2997 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2998 return str;
2999 }
3000 }
3001 }
3002 }
3003 return NULL;
3004 }
3006 ThreadPriority JavaThread::java_priority() const {
3007 oop thr_oop = threadObj();
3008 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3009 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3010 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3011 return priority;
3012 }
3014 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3016 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3017 // Link Java Thread object <-> C++ Thread
3019 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3020 // and put it into a new Handle. The Handle "thread_oop" can then
3021 // be used to pass the C++ thread object to other methods.
3023 // Set the Java level thread object (jthread) field of the
3024 // new thread (a JavaThread *) to C++ thread object using the
3025 // "thread_oop" handle.
3027 // Set the thread field (a JavaThread *) of the
3028 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3030 Handle thread_oop(Thread::current(),
3031 JNIHandles::resolve_non_null(jni_thread));
3032 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3033 "must be initialized");
3034 set_threadObj(thread_oop());
3035 java_lang_Thread::set_thread(thread_oop(), this);
3037 if (prio == NoPriority) {
3038 prio = java_lang_Thread::priority(thread_oop());
3039 assert(prio != NoPriority, "A valid priority should be present");
3040 }
3042 // Push the Java priority down to the native thread; needs Threads_lock
3043 Thread::set_priority(this, prio);
3045 prepare_ext();
3047 // Add the new thread to the Threads list and set it in motion.
3048 // We must have threads lock in order to call Threads::add.
3049 // It is crucial that we do not block before the thread is
3050 // added to the Threads list for if a GC happens, then the java_thread oop
3051 // will not be visited by GC.
3052 Threads::add(this);
3053 }
3055 oop JavaThread::current_park_blocker() {
3056 // Support for JSR-166 locks
3057 oop thread_oop = threadObj();
3058 if (thread_oop != NULL &&
3059 JDK_Version::current().supports_thread_park_blocker()) {
3060 return java_lang_Thread::park_blocker(thread_oop);
3061 }
3062 return NULL;
3063 }
3066 void JavaThread::print_stack_on(outputStream* st) {
3067 if (!has_last_Java_frame()) return;
3068 ResourceMark rm;
3069 HandleMark hm;
3071 RegisterMap reg_map(this);
3072 vframe* start_vf = last_java_vframe(®_map);
3073 int count = 0;
3074 for (vframe* f = start_vf; f; f = f->sender() ) {
3075 if (f->is_java_frame()) {
3076 javaVFrame* jvf = javaVFrame::cast(f);
3077 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3079 // Print out lock information
3080 if (JavaMonitorsInStackTrace) {
3081 jvf->print_lock_info_on(st, count);
3082 }
3083 } else {
3084 // Ignore non-Java frames
3085 }
3087 // Bail-out case for too deep stacks
3088 count++;
3089 if (MaxJavaStackTraceDepth == count) return;
3090 }
3091 }
3094 // JVMTI PopFrame support
3095 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3096 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3097 if (in_bytes(size_in_bytes) != 0) {
3098 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3099 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3100 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3101 }
3102 }
3104 void* JavaThread::popframe_preserved_args() {
3105 return _popframe_preserved_args;
3106 }
3108 ByteSize JavaThread::popframe_preserved_args_size() {
3109 return in_ByteSize(_popframe_preserved_args_size);
3110 }
3112 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3113 int sz = in_bytes(popframe_preserved_args_size());
3114 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3115 return in_WordSize(sz / wordSize);
3116 }
3118 void JavaThread::popframe_free_preserved_args() {
3119 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3120 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3121 _popframe_preserved_args = NULL;
3122 _popframe_preserved_args_size = 0;
3123 }
3125 #ifndef PRODUCT
3127 void JavaThread::trace_frames() {
3128 tty->print_cr("[Describe stack]");
3129 int frame_no = 1;
3130 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3131 tty->print(" %d. ", frame_no++);
3132 fst.current()->print_value_on(tty,this);
3133 tty->cr();
3134 }
3135 }
3137 class PrintAndVerifyOopClosure: public OopClosure {
3138 protected:
3139 template <class T> inline void do_oop_work(T* p) {
3140 oop obj = oopDesc::load_decode_heap_oop(p);
3141 if (obj == NULL) return;
3142 tty->print(INTPTR_FORMAT ": ", p);
3143 if (obj->is_oop_or_null()) {
3144 if (obj->is_objArray()) {
3145 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3146 } else {
3147 obj->print();
3148 }
3149 } else {
3150 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3151 }
3152 tty->cr();
3153 }
3154 public:
3155 virtual void do_oop(oop* p) { do_oop_work(p); }
3156 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3157 };
3160 static void oops_print(frame* f, const RegisterMap *map) {
3161 PrintAndVerifyOopClosure print;
3162 f->print_value();
3163 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3164 }
3166 // Print our all the locations that contain oops and whether they are
3167 // valid or not. This useful when trying to find the oldest frame
3168 // where an oop has gone bad since the frame walk is from youngest to
3169 // oldest.
3170 void JavaThread::trace_oops() {
3171 tty->print_cr("[Trace oops]");
3172 frames_do(oops_print);
3173 }
3176 #ifdef ASSERT
3177 // Print or validate the layout of stack frames
3178 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3179 ResourceMark rm;
3180 PRESERVE_EXCEPTION_MARK;
3181 FrameValues values;
3182 int frame_no = 0;
3183 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3184 fst.current()->describe(values, ++frame_no);
3185 if (depth == frame_no) break;
3186 }
3187 if (validate_only) {
3188 values.validate();
3189 } else {
3190 tty->print_cr("[Describe stack layout]");
3191 values.print(this);
3192 }
3193 }
3194 #endif
3196 void JavaThread::trace_stack_from(vframe* start_vf) {
3197 ResourceMark rm;
3198 int vframe_no = 1;
3199 for (vframe* f = start_vf; f; f = f->sender() ) {
3200 if (f->is_java_frame()) {
3201 javaVFrame::cast(f)->print_activation(vframe_no++);
3202 } else {
3203 f->print();
3204 }
3205 if (vframe_no > StackPrintLimit) {
3206 tty->print_cr("...<more frames>...");
3207 return;
3208 }
3209 }
3210 }
3213 void JavaThread::trace_stack() {
3214 if (!has_last_Java_frame()) return;
3215 ResourceMark rm;
3216 HandleMark hm;
3217 RegisterMap reg_map(this);
3218 trace_stack_from(last_java_vframe(®_map));
3219 }
3222 #endif // PRODUCT
3225 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3226 assert(reg_map != NULL, "a map must be given");
3227 frame f = last_frame();
3228 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3229 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3230 }
3231 return NULL;
3232 }
3235 Klass* JavaThread::security_get_caller_class(int depth) {
3236 vframeStream vfst(this);
3237 vfst.security_get_caller_frame(depth);
3238 if (!vfst.at_end()) {
3239 return vfst.method()->method_holder();
3240 }
3241 return NULL;
3242 }
3244 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3245 assert(thread->is_Compiler_thread(), "must be compiler thread");
3246 CompileBroker::compiler_thread_loop();
3247 }
3249 // Create a CompilerThread
3250 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3251 : JavaThread(&compiler_thread_entry) {
3252 _env = NULL;
3253 _log = NULL;
3254 _task = NULL;
3255 _queue = queue;
3256 _counters = counters;
3257 _buffer_blob = NULL;
3258 _scanned_nmethod = NULL;
3259 _compiler = NULL;
3261 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3262 resource_area()->bias_to(mtCompiler);
3264 #ifndef PRODUCT
3265 _ideal_graph_printer = NULL;
3266 #endif
3267 }
3269 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3270 JavaThread::oops_do(f, cld_f, cf);
3271 if (_scanned_nmethod != NULL && cf != NULL) {
3272 // Safepoints can occur when the sweeper is scanning an nmethod so
3273 // process it here to make sure it isn't unloaded in the middle of
3274 // a scan.
3275 cf->do_code_blob(_scanned_nmethod);
3276 }
3277 }
3280 // ======= Threads ========
3282 // The Threads class links together all active threads, and provides
3283 // operations over all threads. It is protected by its own Mutex
3284 // lock, which is also used in other contexts to protect thread
3285 // operations from having the thread being operated on from exiting
3286 // and going away unexpectedly (e.g., safepoint synchronization)
3288 JavaThread* Threads::_thread_list = NULL;
3289 int Threads::_number_of_threads = 0;
3290 int Threads::_number_of_non_daemon_threads = 0;
3291 int Threads::_return_code = 0;
3292 size_t JavaThread::_stack_size_at_create = 0;
3293 #ifdef ASSERT
3294 bool Threads::_vm_complete = false;
3295 #endif
3297 // All JavaThreads
3298 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3300 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3301 void Threads::threads_do(ThreadClosure* tc) {
3302 assert_locked_or_safepoint(Threads_lock);
3303 // ALL_JAVA_THREADS iterates through all JavaThreads
3304 ALL_JAVA_THREADS(p) {
3305 tc->do_thread(p);
3306 }
3307 // Someday we could have a table or list of all non-JavaThreads.
3308 // For now, just manually iterate through them.
3309 tc->do_thread(VMThread::vm_thread());
3310 Universe::heap()->gc_threads_do(tc);
3311 WatcherThread *wt = WatcherThread::watcher_thread();
3312 // Strictly speaking, the following NULL check isn't sufficient to make sure
3313 // the data for WatcherThread is still valid upon being examined. However,
3314 // considering that WatchThread terminates when the VM is on the way to
3315 // exit at safepoint, the chance of the above is extremely small. The right
3316 // way to prevent termination of WatcherThread would be to acquire
3317 // Terminator_lock, but we can't do that without violating the lock rank
3318 // checking in some cases.
3319 if (wt != NULL)
3320 tc->do_thread(wt);
3322 #if INCLUDE_JFR
3323 Thread* sampler_thread = Jfr::sampler_thread();
3324 if (sampler_thread != NULL) {
3325 tc->do_thread(sampler_thread);
3326 }
3328 #endif
3330 // If CompilerThreads ever become non-JavaThreads, add them here
3331 }
3333 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3335 extern void JDK_Version_init();
3337 // Preinitialize version info.
3338 VM_Version::early_initialize();
3340 // Check version
3341 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3343 // Initialize the output stream module
3344 ostream_init();
3346 // Process java launcher properties.
3347 Arguments::process_sun_java_launcher_properties(args);
3349 // Initialize the os module before using TLS
3350 os::init();
3352 // Initialize system properties.
3353 Arguments::init_system_properties();
3355 // So that JDK version can be used as a discrimintor when parsing arguments
3356 JDK_Version_init();
3358 // Update/Initialize System properties after JDK version number is known
3359 Arguments::init_version_specific_system_properties();
3361 // Parse arguments
3362 // Note: this internally calls os::init_container_support()
3363 jint parse_result = Arguments::parse(args);
3364 if (parse_result != JNI_OK) return parse_result;
3366 os::init_before_ergo();
3368 jint ergo_result = Arguments::apply_ergo();
3369 if (ergo_result != JNI_OK) return ergo_result;
3371 if (PauseAtStartup) {
3372 os::pause();
3373 }
3375 #ifndef USDT2
3376 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3377 #else /* USDT2 */
3378 HOTSPOT_VM_INIT_BEGIN();
3379 #endif /* USDT2 */
3381 // Record VM creation timing statistics
3382 TraceVmCreationTime create_vm_timer;
3383 create_vm_timer.start();
3385 // Timing (must come after argument parsing)
3386 TraceTime timer("Create VM", TraceStartupTime);
3388 // Initialize the os module after parsing the args
3389 jint os_init_2_result = os::init_2();
3390 if (os_init_2_result != JNI_OK) return os_init_2_result;
3392 jint adjust_after_os_result = Arguments::adjust_after_os();
3393 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3395 // intialize TLS
3396 ThreadLocalStorage::init();
3398 // Initialize output stream logging
3399 ostream_init_log();
3401 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3402 // Must be before create_vm_init_agents()
3403 if (Arguments::init_libraries_at_startup()) {
3404 convert_vm_init_libraries_to_agents();
3405 }
3407 // Launch -agentlib/-agentpath and converted -Xrun agents
3408 if (Arguments::init_agents_at_startup()) {
3409 create_vm_init_agents();
3410 }
3412 // Initialize Threads state
3413 _thread_list = NULL;
3414 _number_of_threads = 0;
3415 _number_of_non_daemon_threads = 0;
3417 // Initialize global data structures and create system classes in heap
3418 vm_init_globals();
3420 // Attach the main thread to this os thread
3421 JavaThread* main_thread = new JavaThread();
3422 main_thread->set_thread_state(_thread_in_vm);
3423 // must do this before set_active_handles and initialize_thread_local_storage
3424 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3425 // change the stack size recorded here to one based on the java thread
3426 // stacksize. This adjusted size is what is used to figure the placement
3427 // of the guard pages.
3428 main_thread->record_stack_base_and_size();
3429 main_thread->initialize_thread_local_storage();
3431 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3433 if (!main_thread->set_as_starting_thread()) {
3434 vm_shutdown_during_initialization(
3435 "Failed necessary internal allocation. Out of swap space");
3436 delete main_thread;
3437 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3438 return JNI_ENOMEM;
3439 }
3441 // Enable guard page *after* os::create_main_thread(), otherwise it would
3442 // crash Linux VM, see notes in os_linux.cpp.
3443 main_thread->create_stack_guard_pages();
3445 // Initialize Java-Level synchronization subsystem
3446 ObjectMonitor::Initialize() ;
3448 // Initialize global modules
3449 jint status = init_globals();
3450 if (status != JNI_OK) {
3451 delete main_thread;
3452 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3453 return status;
3454 }
3456 JFR_ONLY(Jfr::on_vm_init();)
3458 // Should be done after the heap is fully created
3459 main_thread->cache_global_variables();
3461 HandleMark hm;
3463 { MutexLocker mu(Threads_lock);
3464 Threads::add(main_thread);
3465 }
3467 // Any JVMTI raw monitors entered in onload will transition into
3468 // real raw monitor. VM is setup enough here for raw monitor enter.
3469 JvmtiExport::transition_pending_onload_raw_monitors();
3471 // Create the VMThread
3472 { TraceTime timer("Start VMThread", TraceStartupTime);
3473 VMThread::create();
3474 Thread* vmthread = VMThread::vm_thread();
3476 if (!os::create_thread(vmthread, os::vm_thread))
3477 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3479 // Wait for the VM thread to become ready, and VMThread::run to initialize
3480 // Monitors can have spurious returns, must always check another state flag
3481 {
3482 MutexLocker ml(Notify_lock);
3483 os::start_thread(vmthread);
3484 while (vmthread->active_handles() == NULL) {
3485 Notify_lock->wait();
3486 }
3487 }
3488 }
3490 assert (Universe::is_fully_initialized(), "not initialized");
3491 if (VerifyDuringStartup) {
3492 // Make sure we're starting with a clean slate.
3493 VM_Verify verify_op;
3494 VMThread::execute(&verify_op);
3495 }
3497 EXCEPTION_MARK;
3499 // At this point, the Universe is initialized, but we have not executed
3500 // any byte code. Now is a good time (the only time) to dump out the
3501 // internal state of the JVM for sharing.
3502 if (DumpSharedSpaces) {
3503 MetaspaceShared::preload_and_dump(CHECK_0);
3504 ShouldNotReachHere();
3505 }
3507 // Always call even when there are not JVMTI environments yet, since environments
3508 // may be attached late and JVMTI must track phases of VM execution
3509 JvmtiExport::enter_start_phase();
3511 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3512 JvmtiExport::post_vm_start();
3514 {
3515 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3517 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3518 create_vm_init_libraries();
3519 }
3521 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3523 // Initialize java_lang.System (needed before creating the thread)
3524 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3525 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3526 Handle thread_group = create_initial_thread_group(CHECK_0);
3527 Universe::set_main_thread_group(thread_group());
3528 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3529 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3530 main_thread->set_threadObj(thread_object);
3531 // Set thread status to running since main thread has
3532 // been started and running.
3533 java_lang_Thread::set_thread_status(thread_object,
3534 java_lang_Thread::RUNNABLE);
3536 // The VM creates & returns objects of this class. Make sure it's initialized.
3537 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3539 // The VM preresolves methods to these classes. Make sure that they get initialized
3540 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3541 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3542 call_initializeSystemClass(CHECK_0);
3544 // get the Java runtime name after java.lang.System is initialized
3545 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3546 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3548 // an instance of OutOfMemory exception has been allocated earlier
3549 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3550 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3551 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3552 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3553 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3554 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3555 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3556 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3557 }
3559 // See : bugid 4211085.
3560 // Background : the static initializer of java.lang.Compiler tries to read
3561 // property"java.compiler" and read & write property "java.vm.info".
3562 // When a security manager is installed through the command line
3563 // option "-Djava.security.manager", the above properties are not
3564 // readable and the static initializer for java.lang.Compiler fails
3565 // resulting in a NoClassDefFoundError. This can happen in any
3566 // user code which calls methods in java.lang.Compiler.
3567 // Hack : the hack is to pre-load and initialize this class, so that only
3568 // system domains are on the stack when the properties are read.
3569 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3570 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3571 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3572 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3573 // Once that is done, we should remove this hack.
3574 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3576 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3577 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3578 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3579 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3580 // This should also be taken out as soon as 4211383 gets fixed.
3581 reset_vm_info_property(CHECK_0);
3583 quicken_jni_functions();
3585 // Set flag that basic initialization has completed. Used by exceptions and various
3586 // debug stuff, that does not work until all basic classes have been initialized.
3587 set_init_completed();
3589 Metaspace::post_initialize();
3591 #ifndef USDT2
3592 HS_DTRACE_PROBE(hotspot, vm__init__end);
3593 #else /* USDT2 */
3594 HOTSPOT_VM_INIT_END();
3595 #endif /* USDT2 */
3597 // record VM initialization completion time
3598 #if INCLUDE_MANAGEMENT
3599 Management::record_vm_init_completed();
3600 #endif // INCLUDE_MANAGEMENT
3602 // Compute system loader. Note that this has to occur after set_init_completed, since
3603 // valid exceptions may be thrown in the process.
3604 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3605 // set_init_completed has just been called, causing exceptions not to be shortcut
3606 // anymore. We call vm_exit_during_initialization directly instead.
3607 SystemDictionary::compute_java_system_loader(THREAD);
3608 if (HAS_PENDING_EXCEPTION) {
3609 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3610 }
3612 #if INCLUDE_ALL_GCS
3613 // Support for ConcurrentMarkSweep. This should be cleaned up
3614 // and better encapsulated. The ugly nested if test would go away
3615 // once things are properly refactored. XXX YSR
3616 if (UseConcMarkSweepGC || UseG1GC) {
3617 if (UseConcMarkSweepGC) {
3618 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3619 } else {
3620 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3621 }
3622 if (HAS_PENDING_EXCEPTION) {
3623 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3624 }
3625 }
3626 #endif // INCLUDE_ALL_GCS
3628 // Always call even when there are not JVMTI environments yet, since environments
3629 // may be attached late and JVMTI must track phases of VM execution
3630 JvmtiExport::enter_live_phase();
3632 // Signal Dispatcher needs to be started before VMInit event is posted
3633 os::signal_init();
3635 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3636 if (!DisableAttachMechanism) {
3637 AttachListener::vm_start();
3638 if (StartAttachListener || AttachListener::init_at_startup()) {
3639 AttachListener::init();
3640 }
3641 }
3643 // Launch -Xrun agents
3644 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3645 // back-end can launch with -Xdebug -Xrunjdwp.
3646 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3647 create_vm_init_libraries();
3648 }
3650 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3651 JvmtiExport::post_vm_initialized();
3653 JFR_ONLY(Jfr::on_vm_start();)
3655 if (CleanChunkPoolAsync) {
3656 Chunk::start_chunk_pool_cleaner_task();
3657 }
3659 // initialize compiler(s)
3660 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3661 CompileBroker::compilation_init();
3662 #endif
3664 if (EnableInvokeDynamic) {
3665 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3666 // It is done after compilers are initialized, because otherwise compilations of
3667 // signature polymorphic MH intrinsics can be missed
3668 // (see SystemDictionary::find_method_handle_intrinsic).
3669 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3670 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3671 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3672 }
3674 #if INCLUDE_MANAGEMENT
3675 Management::initialize(THREAD);
3676 #endif // INCLUDE_MANAGEMENT
3678 if (HAS_PENDING_EXCEPTION) {
3679 // management agent fails to start possibly due to
3680 // configuration problem and is responsible for printing
3681 // stack trace if appropriate. Simply exit VM.
3682 vm_exit(1);
3683 }
3685 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3686 if (MemProfiling) MemProfiler::engage();
3687 StatSampler::engage();
3688 if (CheckJNICalls) JniPeriodicChecker::engage();
3690 BiasedLocking::init();
3692 #if INCLUDE_RTM_OPT
3693 RTMLockingCounters::init();
3694 #endif
3696 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3697 call_postVMInitHook(THREAD);
3698 // The Java side of PostVMInitHook.run must deal with all
3699 // exceptions and provide means of diagnosis.
3700 if (HAS_PENDING_EXCEPTION) {
3701 CLEAR_PENDING_EXCEPTION;
3702 }
3703 }
3705 {
3706 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3707 // Make sure the watcher thread can be started by WatcherThread::start()
3708 // or by dynamic enrollment.
3709 WatcherThread::make_startable();
3710 // Start up the WatcherThread if there are any periodic tasks
3711 // NOTE: All PeriodicTasks should be registered by now. If they
3712 // aren't, late joiners might appear to start slowly (we might
3713 // take a while to process their first tick).
3714 if (PeriodicTask::num_tasks() > 0) {
3715 WatcherThread::start();
3716 }
3717 }
3719 create_vm_timer.end();
3720 #ifdef ASSERT
3721 _vm_complete = true;
3722 #endif
3723 return JNI_OK;
3724 }
3726 // type for the Agent_OnLoad and JVM_OnLoad entry points
3727 extern "C" {
3728 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3729 }
3730 // Find a command line agent library and return its entry point for
3731 // -agentlib: -agentpath: -Xrun
3732 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3733 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3734 OnLoadEntry_t on_load_entry = NULL;
3735 void *library = NULL;
3737 if (!agent->valid()) {
3738 char buffer[JVM_MAXPATHLEN];
3739 char ebuf[1024];
3740 const char *name = agent->name();
3741 const char *msg = "Could not find agent library ";
3743 // First check to see if agent is statically linked into executable
3744 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3745 library = agent->os_lib();
3746 } else if (agent->is_absolute_path()) {
3747 library = os::dll_load(name, ebuf, sizeof ebuf);
3748 if (library == NULL) {
3749 const char *sub_msg = " in absolute path, with error: ";
3750 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3751 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3752 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3753 // If we can't find the agent, exit.
3754 vm_exit_during_initialization(buf, NULL);
3755 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3756 }
3757 } else {
3758 // Try to load the agent from the standard dll directory
3759 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3760 name)) {
3761 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3762 }
3763 if (library == NULL) { // Try the local directory
3764 char ns[1] = {0};
3765 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3766 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3767 }
3768 if (library == NULL) {
3769 const char *sub_msg = " on the library path, with error: ";
3770 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3771 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3772 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3773 // If we can't find the agent, exit.
3774 vm_exit_during_initialization(buf, NULL);
3775 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3776 }
3777 }
3778 }
3779 agent->set_os_lib(library);
3780 agent->set_valid();
3781 }
3783 // Find the OnLoad function.
3784 on_load_entry =
3785 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3786 false,
3787 on_load_symbols,
3788 num_symbol_entries));
3789 return on_load_entry;
3790 }
3792 // Find the JVM_OnLoad entry point
3793 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3794 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3795 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3796 }
3798 // Find the Agent_OnLoad entry point
3799 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3800 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3801 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3802 }
3804 // For backwards compatibility with -Xrun
3805 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3806 // treated like -agentpath:
3807 // Must be called before agent libraries are created
3808 void Threads::convert_vm_init_libraries_to_agents() {
3809 AgentLibrary* agent;
3810 AgentLibrary* next;
3812 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3813 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3814 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3816 // If there is an JVM_OnLoad function it will get called later,
3817 // otherwise see if there is an Agent_OnLoad
3818 if (on_load_entry == NULL) {
3819 on_load_entry = lookup_agent_on_load(agent);
3820 if (on_load_entry != NULL) {
3821 // switch it to the agent list -- so that Agent_OnLoad will be called,
3822 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3823 Arguments::convert_library_to_agent(agent);
3824 } else {
3825 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3826 }
3827 }
3828 }
3829 }
3831 // Create agents for -agentlib: -agentpath: and converted -Xrun
3832 // Invokes Agent_OnLoad
3833 // Called very early -- before JavaThreads exist
3834 void Threads::create_vm_init_agents() {
3835 extern struct JavaVM_ main_vm;
3836 AgentLibrary* agent;
3838 JvmtiExport::enter_onload_phase();
3840 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3841 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3843 if (on_load_entry != NULL) {
3844 // Invoke the Agent_OnLoad function
3845 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3846 if (err != JNI_OK) {
3847 vm_exit_during_initialization("agent library failed to init", agent->name());
3848 }
3849 } else {
3850 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3851 }
3852 }
3853 JvmtiExport::enter_primordial_phase();
3854 }
3856 extern "C" {
3857 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3858 }
3860 void Threads::shutdown_vm_agents() {
3861 // Send any Agent_OnUnload notifications
3862 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3863 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3864 extern struct JavaVM_ main_vm;
3865 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3867 // Find the Agent_OnUnload function.
3868 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3869 os::find_agent_function(agent,
3870 false,
3871 on_unload_symbols,
3872 num_symbol_entries));
3874 // Invoke the Agent_OnUnload function
3875 if (unload_entry != NULL) {
3876 JavaThread* thread = JavaThread::current();
3877 ThreadToNativeFromVM ttn(thread);
3878 HandleMark hm(thread);
3879 (*unload_entry)(&main_vm);
3880 }
3881 }
3882 }
3884 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3885 // Invokes JVM_OnLoad
3886 void Threads::create_vm_init_libraries() {
3887 extern struct JavaVM_ main_vm;
3888 AgentLibrary* agent;
3890 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3891 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3893 if (on_load_entry != NULL) {
3894 // Invoke the JVM_OnLoad function
3895 JavaThread* thread = JavaThread::current();
3896 ThreadToNativeFromVM ttn(thread);
3897 HandleMark hm(thread);
3898 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3899 if (err != JNI_OK) {
3900 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3901 }
3902 } else {
3903 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3904 }
3905 }
3906 }
3908 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3909 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3911 JavaThread* java_thread = NULL;
3912 // Sequential search for now. Need to do better optimization later.
3913 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3914 oop tobj = thread->threadObj();
3915 if (!thread->is_exiting() &&
3916 tobj != NULL &&
3917 java_tid == java_lang_Thread::thread_id(tobj)) {
3918 java_thread = thread;
3919 break;
3920 }
3921 }
3922 return java_thread;
3923 }
3926 // Last thread running calls java.lang.Shutdown.shutdown()
3927 void JavaThread::invoke_shutdown_hooks() {
3928 HandleMark hm(this);
3930 // We could get here with a pending exception, if so clear it now.
3931 if (this->has_pending_exception()) {
3932 this->clear_pending_exception();
3933 }
3935 EXCEPTION_MARK;
3936 Klass* k =
3937 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3938 THREAD);
3939 if (k != NULL) {
3940 // SystemDictionary::resolve_or_null will return null if there was
3941 // an exception. If we cannot load the Shutdown class, just don't
3942 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3943 // and finalizers (if runFinalizersOnExit is set) won't be run.
3944 // Note that if a shutdown hook was registered or runFinalizersOnExit
3945 // was called, the Shutdown class would have already been loaded
3946 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3947 instanceKlassHandle shutdown_klass (THREAD, k);
3948 JavaValue result(T_VOID);
3949 JavaCalls::call_static(&result,
3950 shutdown_klass,
3951 vmSymbols::shutdown_method_name(),
3952 vmSymbols::void_method_signature(),
3953 THREAD);
3954 }
3955 CLEAR_PENDING_EXCEPTION;
3956 }
3958 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3959 // the program falls off the end of main(). Another VM exit path is through
3960 // vm_exit() when the program calls System.exit() to return a value or when
3961 // there is a serious error in VM. The two shutdown paths are not exactly
3962 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3963 // and VM_Exit op at VM level.
3964 //
3965 // Shutdown sequence:
3966 // + Shutdown native memory tracking if it is on
3967 // + Wait until we are the last non-daemon thread to execute
3968 // <-- every thing is still working at this moment -->
3969 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3970 // shutdown hooks, run finalizers if finalization-on-exit
3971 // + Call before_exit(), prepare for VM exit
3972 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3973 // currently the only user of this mechanism is File.deleteOnExit())
3974 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3975 // post thread end and vm death events to JVMTI,
3976 // stop signal thread
3977 // + Call JavaThread::exit(), it will:
3978 // > release JNI handle blocks, remove stack guard pages
3979 // > remove this thread from Threads list
3980 // <-- no more Java code from this thread after this point -->
3981 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3982 // the compiler threads at safepoint
3983 // <-- do not use anything that could get blocked by Safepoint -->
3984 // + Disable tracing at JNI/JVM barriers
3985 // + Set _vm_exited flag for threads that are still running native code
3986 // + Delete this thread
3987 // + Call exit_globals()
3988 // > deletes tty
3989 // > deletes PerfMemory resources
3990 // + Return to caller
3992 bool Threads::destroy_vm() {
3993 JavaThread* thread = JavaThread::current();
3995 #ifdef ASSERT
3996 _vm_complete = false;
3997 #endif
3998 // Wait until we are the last non-daemon thread to execute
3999 { MutexLocker nu(Threads_lock);
4000 while (Threads::number_of_non_daemon_threads() > 1 )
4001 // This wait should make safepoint checks, wait without a timeout,
4002 // and wait as a suspend-equivalent condition.
4003 //
4004 // Note: If the FlatProfiler is running and this thread is waiting
4005 // for another non-daemon thread to finish, then the FlatProfiler
4006 // is waiting for the external suspend request on this thread to
4007 // complete. wait_for_ext_suspend_completion() will eventually
4008 // timeout, but that takes time. Making this wait a suspend-
4009 // equivalent condition solves that timeout problem.
4010 //
4011 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4012 Mutex::_as_suspend_equivalent_flag);
4013 }
4015 EventShutdown e;
4016 if (e.should_commit()) {
4017 e.set_reason("No remaining non-daemon Java threads");
4018 e.commit();
4019 }
4021 // Hang forever on exit if we are reporting an error.
4022 if (ShowMessageBoxOnError && is_error_reported()) {
4023 os::infinite_sleep();
4024 }
4025 os::wait_for_keypress_at_exit();
4027 if (JDK_Version::is_jdk12x_version()) {
4028 // We are the last thread running, so check if finalizers should be run.
4029 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4030 HandleMark rm(thread);
4031 Universe::run_finalizers_on_exit();
4032 } else {
4033 // run Java level shutdown hooks
4034 thread->invoke_shutdown_hooks();
4035 }
4037 before_exit(thread);
4039 thread->exit(true);
4041 // Stop VM thread.
4042 {
4043 // 4945125 The vm thread comes to a safepoint during exit.
4044 // GC vm_operations can get caught at the safepoint, and the
4045 // heap is unparseable if they are caught. Grab the Heap_lock
4046 // to prevent this. The GC vm_operations will not be able to
4047 // queue until after the vm thread is dead. After this point,
4048 // we'll never emerge out of the safepoint before the VM exits.
4050 MutexLocker ml(Heap_lock);
4052 VMThread::wait_for_vm_thread_exit();
4053 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4054 VMThread::destroy();
4055 }
4057 // clean up ideal graph printers
4058 #if defined(COMPILER2) && !defined(PRODUCT)
4059 IdealGraphPrinter::clean_up();
4060 #endif
4062 // Now, all Java threads are gone except daemon threads. Daemon threads
4063 // running Java code or in VM are stopped by the Safepoint. However,
4064 // daemon threads executing native code are still running. But they
4065 // will be stopped at native=>Java/VM barriers. Note that we can't
4066 // simply kill or suspend them, as it is inherently deadlock-prone.
4068 #ifndef PRODUCT
4069 // disable function tracing at JNI/JVM barriers
4070 TraceJNICalls = false;
4071 TraceJVMCalls = false;
4072 TraceRuntimeCalls = false;
4073 #endif
4075 VM_Exit::set_vm_exited();
4077 notify_vm_shutdown();
4079 delete thread;
4081 // exit_globals() will delete tty
4082 exit_globals();
4084 return true;
4085 }
4088 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4089 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4090 return is_supported_jni_version(version);
4091 }
4094 jboolean Threads::is_supported_jni_version(jint version) {
4095 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4096 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4097 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4098 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4099 return JNI_FALSE;
4100 }
4103 void Threads::add(JavaThread* p, bool force_daemon) {
4104 // The threads lock must be owned at this point
4105 assert_locked_or_safepoint(Threads_lock);
4107 // See the comment for this method in thread.hpp for its purpose and
4108 // why it is called here.
4109 p->initialize_queues();
4110 p->set_next(_thread_list);
4111 _thread_list = p;
4112 _number_of_threads++;
4113 oop threadObj = p->threadObj();
4114 bool daemon = true;
4115 // Bootstrapping problem: threadObj can be null for initial
4116 // JavaThread (or for threads attached via JNI)
4117 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4118 _number_of_non_daemon_threads++;
4119 daemon = false;
4120 }
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();
4167 } // unlock Threads_lock
4169 // Since Events::log uses a lock, we grab it outside the Threads_lock
4170 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4171 }
4173 // Threads_lock must be held when this is called (or must be called during a safepoint)
4174 bool Threads::includes(JavaThread* p) {
4175 assert(Threads_lock->is_locked(), "sanity check");
4176 ALL_JAVA_THREADS(q) {
4177 if (q == p ) {
4178 return true;
4179 }
4180 }
4181 return false;
4182 }
4184 // Operations on the Threads list for GC. These are not explicitly locked,
4185 // but the garbage collector must provide a safe context for them to run.
4186 // In particular, these things should never be called when the Threads_lock
4187 // is held by some other thread. (Note: the Safepoint abstraction also
4188 // uses the Threads_lock to gurantee this property. It also makes sure that
4189 // all threads gets blocked when exiting or starting).
4191 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4192 ALL_JAVA_THREADS(p) {
4193 p->oops_do(f, cld_f, cf);
4194 }
4195 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4196 }
4198 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4199 // Introduce a mechanism allowing parallel threads to claim threads as
4200 // root groups. Overhead should be small enough to use all the time,
4201 // even in sequential code.
4202 SharedHeap* sh = SharedHeap::heap();
4203 // Cannot yet substitute active_workers for n_par_threads
4204 // because of G1CollectedHeap::verify() use of
4205 // SharedHeap::process_roots(). n_par_threads == 0 will
4206 // turn off parallelism in process_roots while active_workers
4207 // is being used for parallelism elsewhere.
4208 bool is_par = sh->n_par_threads() > 0;
4209 assert(!is_par ||
4210 (SharedHeap::heap()->n_par_threads() ==
4211 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4212 int cp = SharedHeap::heap()->strong_roots_parity();
4213 ALL_JAVA_THREADS(p) {
4214 if (p->claim_oops_do(is_par, cp)) {
4215 p->oops_do(f, cld_f, cf);
4216 }
4217 }
4218 VMThread* vmt = VMThread::vm_thread();
4219 if (vmt->claim_oops_do(is_par, cp)) {
4220 vmt->oops_do(f, cld_f, cf);
4221 }
4222 }
4224 #if INCLUDE_ALL_GCS
4225 // Used by ParallelScavenge
4226 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4227 ALL_JAVA_THREADS(p) {
4228 q->enqueue(new ThreadRootsTask(p));
4229 }
4230 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4231 }
4233 // Used by Parallel Old
4234 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4235 ALL_JAVA_THREADS(p) {
4236 q->enqueue(new ThreadRootsMarkingTask(p));
4237 }
4238 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4239 }
4240 #endif // INCLUDE_ALL_GCS
4242 void Threads::nmethods_do(CodeBlobClosure* cf) {
4243 ALL_JAVA_THREADS(p) {
4244 p->nmethods_do(cf);
4245 }
4246 VMThread::vm_thread()->nmethods_do(cf);
4247 }
4249 void Threads::metadata_do(void f(Metadata*)) {
4250 ALL_JAVA_THREADS(p) {
4251 p->metadata_do(f);
4252 }
4253 }
4255 void Threads::gc_epilogue() {
4256 ALL_JAVA_THREADS(p) {
4257 p->gc_epilogue();
4258 }
4259 }
4261 void Threads::gc_prologue() {
4262 ALL_JAVA_THREADS(p) {
4263 p->gc_prologue();
4264 }
4265 }
4267 void Threads::deoptimized_wrt_marked_nmethods() {
4268 ALL_JAVA_THREADS(p) {
4269 p->deoptimized_wrt_marked_nmethods();
4270 }
4271 }
4274 // Get count Java threads that are waiting to enter the specified monitor.
4275 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4276 address monitor, bool doLock) {
4277 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4278 "must grab Threads_lock or be at safepoint");
4279 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4281 int i = 0;
4282 {
4283 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4284 ALL_JAVA_THREADS(p) {
4285 if (p->is_Compiler_thread()) continue;
4287 address pending = (address)p->current_pending_monitor();
4288 if (pending == monitor) { // found a match
4289 if (i < count) result->append(p); // save the first count matches
4290 i++;
4291 }
4292 }
4293 }
4294 return result;
4295 }
4298 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4299 assert(doLock ||
4300 Threads_lock->owned_by_self() ||
4301 SafepointSynchronize::is_at_safepoint(),
4302 "must grab Threads_lock or be at safepoint");
4304 // NULL owner means not locked so we can skip the search
4305 if (owner == NULL) return NULL;
4307 {
4308 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4309 ALL_JAVA_THREADS(p) {
4310 // first, see if owner is the address of a Java thread
4311 if (owner == (address)p) return p;
4312 }
4313 }
4314 // Cannot assert on lack of success here since this function may be
4315 // used by code that is trying to report useful problem information
4316 // like deadlock detection.
4317 if (UseHeavyMonitors) return NULL;
4319 //
4320 // If we didn't find a matching Java thread and we didn't force use of
4321 // heavyweight monitors, then the owner is the stack address of the
4322 // Lock Word in the owning Java thread's stack.
4323 //
4324 JavaThread* the_owner = NULL;
4325 {
4326 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4327 ALL_JAVA_THREADS(q) {
4328 if (q->is_lock_owned(owner)) {
4329 the_owner = q;
4330 break;
4331 }
4332 }
4333 }
4334 // cannot assert on lack of success here; see above comment
4335 return the_owner;
4336 }
4338 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4339 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4340 char buf[32];
4341 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4343 st->print_cr("Full thread dump %s (%s %s):",
4344 Abstract_VM_Version::vm_name(),
4345 Abstract_VM_Version::vm_release(),
4346 Abstract_VM_Version::vm_info_string()
4347 );
4348 st->cr();
4350 #if INCLUDE_ALL_GCS
4351 // Dump concurrent locks
4352 ConcurrentLocksDump concurrent_locks;
4353 if (print_concurrent_locks) {
4354 concurrent_locks.dump_at_safepoint();
4355 }
4356 #endif // INCLUDE_ALL_GCS
4358 ALL_JAVA_THREADS(p) {
4359 ResourceMark rm;
4360 p->print_on(st);
4361 if (print_stacks) {
4362 if (internal_format) {
4363 p->trace_stack();
4364 } else {
4365 p->print_stack_on(st);
4366 }
4367 }
4368 st->cr();
4369 #if INCLUDE_ALL_GCS
4370 if (print_concurrent_locks) {
4371 concurrent_locks.print_locks_on(p, st);
4372 }
4373 #endif // INCLUDE_ALL_GCS
4374 }
4376 VMThread::vm_thread()->print_on(st);
4377 st->cr();
4378 Universe::heap()->print_gc_threads_on(st);
4379 WatcherThread* wt = WatcherThread::watcher_thread();
4380 if (wt != NULL) {
4381 wt->print_on(st);
4382 st->cr();
4383 }
4384 CompileBroker::print_compiler_threads_on(st);
4385 st->flush();
4386 }
4388 // Threads::print_on_error() is called by fatal error handler. It's possible
4389 // that VM is not at safepoint and/or current thread is inside signal handler.
4390 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4391 // memory (even in resource area), it might deadlock the error handler.
4392 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4393 bool found_current = false;
4394 st->print_cr("Java Threads: ( => current thread )");
4395 ALL_JAVA_THREADS(thread) {
4396 bool is_current = (current == thread);
4397 found_current = found_current || is_current;
4399 st->print("%s", is_current ? "=>" : " ");
4401 st->print(PTR_FORMAT, thread);
4402 st->print(" ");
4403 thread->print_on_error(st, buf, buflen);
4404 st->cr();
4405 }
4406 st->cr();
4408 st->print_cr("Other Threads:");
4409 if (VMThread::vm_thread()) {
4410 bool is_current = (current == VMThread::vm_thread());
4411 found_current = found_current || is_current;
4412 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4414 st->print(PTR_FORMAT, VMThread::vm_thread());
4415 st->print(" ");
4416 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4417 st->cr();
4418 }
4419 WatcherThread* wt = WatcherThread::watcher_thread();
4420 if (wt != NULL) {
4421 bool is_current = (current == wt);
4422 found_current = found_current || is_current;
4423 st->print("%s", is_current ? "=>" : " ");
4425 st->print(PTR_FORMAT, wt);
4426 st->print(" ");
4427 wt->print_on_error(st, buf, buflen);
4428 st->cr();
4429 }
4430 if (!found_current) {
4431 st->cr();
4432 st->print("=>" PTR_FORMAT " (exited) ", current);
4433 current->print_on_error(st, buf, buflen);
4434 st->cr();
4435 }
4436 }
4438 // Internal SpinLock and Mutex
4439 // Based on ParkEvent
4441 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4442 //
4443 // We employ SpinLocks _only for low-contention, fixed-length
4444 // short-duration critical sections where we're concerned
4445 // about native mutex_t or HotSpot Mutex:: latency.
4446 // The mux construct provides a spin-then-block mutual exclusion
4447 // mechanism.
4448 //
4449 // Testing has shown that contention on the ListLock guarding gFreeList
4450 // is common. If we implement ListLock as a simple SpinLock it's common
4451 // for the JVM to devolve to yielding with little progress. This is true
4452 // despite the fact that the critical sections protected by ListLock are
4453 // extremely short.
4454 //
4455 // TODO-FIXME: ListLock should be of type SpinLock.
4456 // We should make this a 1st-class type, integrated into the lock
4457 // hierarchy as leaf-locks. Critically, the SpinLock structure
4458 // should have sufficient padding to avoid false-sharing and excessive
4459 // cache-coherency traffic.
4462 typedef volatile int SpinLockT ;
4464 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4465 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4466 return ; // normal fast-path return
4467 }
4469 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4470 TEVENT (SpinAcquire - ctx) ;
4471 int ctr = 0 ;
4472 int Yields = 0 ;
4473 for (;;) {
4474 while (*adr != 0) {
4475 ++ctr ;
4476 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4477 if (Yields > 5) {
4478 os::naked_short_sleep(1);
4479 } else {
4480 os::NakedYield() ;
4481 ++Yields ;
4482 }
4483 } else {
4484 SpinPause() ;
4485 }
4486 }
4487 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4488 }
4489 }
4491 void Thread::SpinRelease (volatile int * adr) {
4492 assert (*adr != 0, "invariant") ;
4493 OrderAccess::fence() ; // guarantee at least release consistency.
4494 // Roach-motel semantics.
4495 // It's safe if subsequent LDs and STs float "up" into the critical section,
4496 // but prior LDs and STs within the critical section can't be allowed
4497 // to reorder or float past the ST that releases the lock.
4498 *adr = 0 ;
4499 }
4501 // muxAcquire and muxRelease:
4502 //
4503 // * muxAcquire and muxRelease support a single-word lock-word construct.
4504 // The LSB of the word is set IFF the lock is held.
4505 // The remainder of the word points to the head of a singly-linked list
4506 // of threads blocked on the lock.
4507 //
4508 // * The current implementation of muxAcquire-muxRelease uses its own
4509 // dedicated Thread._MuxEvent instance. If we're interested in
4510 // minimizing the peak number of extant ParkEvent instances then
4511 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4512 // as certain invariants were satisfied. Specifically, care would need
4513 // to be taken with regards to consuming unpark() "permits".
4514 // A safe rule of thumb is that a thread would never call muxAcquire()
4515 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4516 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4517 // consume an unpark() permit intended for monitorenter, for instance.
4518 // One way around this would be to widen the restricted-range semaphore
4519 // implemented in park(). Another alternative would be to provide
4520 // multiple instances of the PlatformEvent() for each thread. One
4521 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4522 //
4523 // * Usage:
4524 // -- Only as leaf locks
4525 // -- for short-term locking only as muxAcquire does not perform
4526 // thread state transitions.
4527 //
4528 // Alternatives:
4529 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4530 // but with parking or spin-then-park instead of pure spinning.
4531 // * Use Taura-Oyama-Yonenzawa locks.
4532 // * It's possible to construct a 1-0 lock if we encode the lockword as
4533 // (List,LockByte). Acquire will CAS the full lockword while Release
4534 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4535 // acquiring threads use timers (ParkTimed) to detect and recover from
4536 // the stranding window. Thread/Node structures must be aligned on 256-byte
4537 // boundaries by using placement-new.
4538 // * Augment MCS with advisory back-link fields maintained with CAS().
4539 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4540 // The validity of the backlinks must be ratified before we trust the value.
4541 // If the backlinks are invalid the exiting thread must back-track through the
4542 // the forward links, which are always trustworthy.
4543 // * Add a successor indication. The LockWord is currently encoded as
4544 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4545 // to provide the usual futile-wakeup optimization.
4546 // See RTStt for details.
4547 // * Consider schedctl.sc_nopreempt to cover the critical section.
4548 //
4551 typedef volatile intptr_t MutexT ; // Mux Lock-word
4552 enum MuxBits { LOCKBIT = 1 } ;
4554 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4555 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4556 if (w == 0) return ;
4557 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4558 return ;
4559 }
4561 TEVENT (muxAcquire - Contention) ;
4562 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4563 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4564 for (;;) {
4565 int its = (os::is_MP() ? 100 : 0) + 1 ;
4567 // Optional spin phase: spin-then-park strategy
4568 while (--its >= 0) {
4569 w = *Lock ;
4570 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4571 return ;
4572 }
4573 }
4575 Self->reset() ;
4576 Self->OnList = intptr_t(Lock) ;
4577 // The following fence() isn't _strictly necessary as the subsequent
4578 // CAS() both serializes execution and ratifies the fetched *Lock value.
4579 OrderAccess::fence();
4580 for (;;) {
4581 w = *Lock ;
4582 if ((w & LOCKBIT) == 0) {
4583 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4584 Self->OnList = 0 ; // hygiene - allows stronger asserts
4585 return ;
4586 }
4587 continue ; // Interference -- *Lock changed -- Just retry
4588 }
4589 assert (w & LOCKBIT, "invariant") ;
4590 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4591 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4592 }
4594 while (Self->OnList != 0) {
4595 Self->park() ;
4596 }
4597 }
4598 }
4600 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4601 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4602 if (w == 0) return ;
4603 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4604 return ;
4605 }
4607 TEVENT (muxAcquire - Contention) ;
4608 ParkEvent * ReleaseAfter = NULL ;
4609 if (ev == NULL) {
4610 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4611 }
4612 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4613 for (;;) {
4614 guarantee (ev->OnList == 0, "invariant") ;
4615 int its = (os::is_MP() ? 100 : 0) + 1 ;
4617 // Optional spin phase: spin-then-park strategy
4618 while (--its >= 0) {
4619 w = *Lock ;
4620 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4621 if (ReleaseAfter != NULL) {
4622 ParkEvent::Release (ReleaseAfter) ;
4623 }
4624 return ;
4625 }
4626 }
4628 ev->reset() ;
4629 ev->OnList = intptr_t(Lock) ;
4630 // The following fence() isn't _strictly necessary as the subsequent
4631 // CAS() both serializes execution and ratifies the fetched *Lock value.
4632 OrderAccess::fence();
4633 for (;;) {
4634 w = *Lock ;
4635 if ((w & LOCKBIT) == 0) {
4636 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4637 ev->OnList = 0 ;
4638 // We call ::Release while holding the outer lock, thus
4639 // artificially lengthening the critical section.
4640 // Consider deferring the ::Release() until the subsequent unlock(),
4641 // after we've dropped the outer lock.
4642 if (ReleaseAfter != NULL) {
4643 ParkEvent::Release (ReleaseAfter) ;
4644 }
4645 return ;
4646 }
4647 continue ; // Interference -- *Lock changed -- Just retry
4648 }
4649 assert (w & LOCKBIT, "invariant") ;
4650 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4651 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4652 }
4654 while (ev->OnList != 0) {
4655 ev->park() ;
4656 }
4657 }
4658 }
4660 // Release() must extract a successor from the list and then wake that thread.
4661 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4662 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4663 // Release() would :
4664 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4665 // (B) Extract a successor from the private list "in-hand"
4666 // (C) attempt to CAS() the residual back into *Lock over null.
4667 // If there were any newly arrived threads and the CAS() would fail.
4668 // In that case Release() would detach the RATs, re-merge the list in-hand
4669 // with the RATs and repeat as needed. Alternately, Release() might
4670 // detach and extract a successor, but then pass the residual list to the wakee.
4671 // The wakee would be responsible for reattaching and remerging before it
4672 // competed for the lock.
4673 //
4674 // Both "pop" and DMR are immune from ABA corruption -- there can be
4675 // multiple concurrent pushers, but only one popper or detacher.
4676 // This implementation pops from the head of the list. This is unfair,
4677 // but tends to provide excellent throughput as hot threads remain hot.
4678 // (We wake recently run threads first).
4680 void Thread::muxRelease (volatile intptr_t * Lock) {
4681 for (;;) {
4682 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4683 assert (w & LOCKBIT, "invariant") ;
4684 if (w == LOCKBIT) return ;
4685 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4686 assert (List != NULL, "invariant") ;
4687 assert (List->OnList == intptr_t(Lock), "invariant") ;
4688 ParkEvent * nxt = List->ListNext ;
4690 // The following CAS() releases the lock and pops the head element.
4691 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4692 continue ;
4693 }
4694 List->OnList = 0 ;
4695 OrderAccess::fence() ;
4696 List->unpark () ;
4697 return ;
4698 }
4699 }
4702 void Threads::verify() {
4703 ALL_JAVA_THREADS(p) {
4704 p->verify();
4705 }
4706 VMThread* thread = VMThread::vm_thread();
4707 if (thread != NULL) thread->verify();
4708 }