Thu, 05 Sep 2019 18:52:27 +0800
Merge
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 /*
26 * This file has been modified by Loongson Technology in 2015. These
27 * modifications are Copyright (c) 2015 Loongson Technology, and are made
28 * available on the same license terms set forth above.
29 */
31 #include "precompiled.hpp"
32 #include "classfile/classLoader.hpp"
33 #include "classfile/javaClasses.hpp"
34 #include "classfile/systemDictionary.hpp"
35 #include "classfile/vmSymbols.hpp"
36 #include "code/scopeDesc.hpp"
37 #include "compiler/compileBroker.hpp"
38 #include "interpreter/interpreter.hpp"
39 #include "interpreter/linkResolver.hpp"
40 #include "interpreter/oopMapCache.hpp"
41 #include "jvmtifiles/jvmtiEnv.hpp"
42 #include "memory/gcLocker.inline.hpp"
43 #include "memory/metaspaceShared.hpp"
44 #include "memory/oopFactory.hpp"
45 #include "memory/universe.inline.hpp"
46 #include "oops/instanceKlass.hpp"
47 #include "oops/objArrayOop.hpp"
48 #include "oops/oop.inline.hpp"
49 #include "oops/symbol.hpp"
50 #include "prims/jvm_misc.hpp"
51 #include "prims/jvmtiExport.hpp"
52 #include "prims/jvmtiThreadState.hpp"
53 #include "prims/privilegedStack.hpp"
54 #include "runtime/arguments.hpp"
55 #include "runtime/biasedLocking.hpp"
56 #include "runtime/deoptimization.hpp"
57 #include "runtime/fprofiler.hpp"
58 #include "runtime/frame.inline.hpp"
59 #include "runtime/init.hpp"
60 #include "runtime/interfaceSupport.hpp"
61 #include "runtime/java.hpp"
62 #include "runtime/javaCalls.hpp"
63 #include "runtime/jniPeriodicChecker.hpp"
64 #include "runtime/memprofiler.hpp"
65 #include "runtime/mutexLocker.hpp"
66 #include "runtime/objectMonitor.hpp"
67 #include "runtime/orderAccess.inline.hpp"
68 #include "runtime/osThread.hpp"
69 #include "runtime/safepoint.hpp"
70 #include "runtime/sharedRuntime.hpp"
71 #include "runtime/statSampler.hpp"
72 #include "runtime/stubRoutines.hpp"
73 #include "runtime/task.hpp"
74 #include "runtime/thread.inline.hpp"
75 #include "runtime/threadCritical.hpp"
76 #include "runtime/threadLocalStorage.hpp"
77 #include "runtime/vframe.hpp"
78 #include "runtime/vframeArray.hpp"
79 #include "runtime/vframe_hp.hpp"
80 #include "runtime/vmThread.hpp"
81 #include "runtime/vm_operations.hpp"
82 #include "services/attachListener.hpp"
83 #include "services/management.hpp"
84 #include "services/memTracker.hpp"
85 #include "services/threadService.hpp"
86 #include "trace/tracing.hpp"
87 #include "trace/traceMacros.hpp"
88 #include "utilities/defaultStream.hpp"
89 #include "utilities/dtrace.hpp"
90 #include "utilities/events.hpp"
91 #include "utilities/preserveException.hpp"
92 #include "utilities/macros.hpp"
93 #ifdef TARGET_OS_FAMILY_linux
94 # include "os_linux.inline.hpp"
95 #endif
96 #ifdef TARGET_OS_FAMILY_solaris
97 # include "os_solaris.inline.hpp"
98 #endif
99 #ifdef TARGET_OS_FAMILY_windows
100 # include "os_windows.inline.hpp"
101 #endif
102 #ifdef TARGET_OS_FAMILY_bsd
103 # include "os_bsd.inline.hpp"
104 #endif
105 #if INCLUDE_ALL_GCS
106 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
107 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
108 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
109 #endif // INCLUDE_ALL_GCS
110 #ifdef COMPILER1
111 #include "c1/c1_Compiler.hpp"
112 #endif
113 #ifdef COMPILER2
114 #include "opto/c2compiler.hpp"
115 #include "opto/idealGraphPrinter.hpp"
116 #endif
117 #if INCLUDE_RTM_OPT
118 #include "runtime/rtmLocking.hpp"
119 #endif
121 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
123 #ifdef DTRACE_ENABLED
125 // Only bother with this argument setup if dtrace is available
127 #ifndef USDT2
128 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
129 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
130 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
131 intptr_t, intptr_t, bool);
132 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
133 intptr_t, intptr_t, bool);
135 #define DTRACE_THREAD_PROBE(probe, javathread) \
136 { \
137 ResourceMark rm(this); \
138 int len = 0; \
139 const char* name = (javathread)->get_thread_name(); \
140 len = strlen(name); \
141 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
142 name, len, \
143 java_lang_Thread::thread_id((javathread)->threadObj()), \
144 (javathread)->osthread()->thread_id(), \
145 java_lang_Thread::is_daemon((javathread)->threadObj())); \
146 }
148 #else /* USDT2 */
150 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
151 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
153 #define DTRACE_THREAD_PROBE(probe, javathread) \
154 { \
155 ResourceMark rm(this); \
156 int len = 0; \
157 const char* name = (javathread)->get_thread_name(); \
158 len = strlen(name); \
159 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
160 (char *) name, len, \
161 java_lang_Thread::thread_id((javathread)->threadObj()), \
162 (uintptr_t) (javathread)->osthread()->thread_id(), \
163 java_lang_Thread::is_daemon((javathread)->threadObj())); \
164 }
166 #endif /* USDT2 */
168 #else // ndef DTRACE_ENABLED
170 #define DTRACE_THREAD_PROBE(probe, javathread)
172 #endif // ndef DTRACE_ENABLED
175 // Class hierarchy
176 // - Thread
177 // - VMThread
178 // - WatcherThread
179 // - ConcurrentMarkSweepThread
180 // - JavaThread
181 // - CompilerThread
183 // ======= Thread ========
184 // Support for forcing alignment of thread objects for biased locking
185 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
186 if (UseBiasedLocking) {
187 const int alignment = markOopDesc::biased_lock_alignment;
188 size_t aligned_size = size + (alignment - sizeof(intptr_t));
189 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
190 : AllocateHeap(aligned_size, flags, CURRENT_PC,
191 AllocFailStrategy::RETURN_NULL);
192 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
193 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
194 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
195 "JavaThread alignment code overflowed allocated storage");
196 if (TraceBiasedLocking) {
197 if (aligned_addr != real_malloc_addr)
198 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
199 real_malloc_addr, aligned_addr);
200 }
201 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
202 return aligned_addr;
203 } else {
204 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
205 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
206 }
207 }
209 void Thread::operator delete(void* p) {
210 if (UseBiasedLocking) {
211 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
212 FreeHeap(real_malloc_addr, mtThread);
213 } else {
214 FreeHeap(p, mtThread);
215 }
216 }
219 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
220 // JavaThread
223 Thread::Thread() {
224 // stack and get_thread
225 set_stack_base(NULL);
226 set_stack_size(0);
227 set_self_raw_id(0);
228 set_lgrp_id(-1);
230 // allocated data structures
231 set_osthread(NULL);
232 set_resource_area(new (mtThread)ResourceArea());
233 DEBUG_ONLY(_current_resource_mark = NULL;)
234 set_handle_area(new (mtThread) HandleArea(NULL));
235 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
236 set_active_handles(NULL);
237 set_free_handle_block(NULL);
238 set_last_handle_mark(NULL);
240 // This initial value ==> never claimed.
241 _oops_do_parity = 0;
243 _metadata_on_stack_buffer = NULL;
245 // the handle mark links itself to last_handle_mark
246 new HandleMark(this);
248 // plain initialization
249 debug_only(_owned_locks = NULL;)
250 debug_only(_allow_allocation_count = 0;)
251 NOT_PRODUCT(_allow_safepoint_count = 0;)
252 NOT_PRODUCT(_skip_gcalot = false;)
253 _jvmti_env_iteration_count = 0;
254 set_allocated_bytes(0);
255 _vm_operation_started_count = 0;
256 _vm_operation_completed_count = 0;
257 _current_pending_monitor = NULL;
258 _current_pending_monitor_is_from_java = true;
259 _current_waiting_monitor = NULL;
260 _num_nested_signal = 0;
261 omFreeList = NULL ;
262 omFreeCount = 0 ;
263 omFreeProvision = 32 ;
264 omInUseList = NULL ;
265 omInUseCount = 0 ;
267 #ifdef ASSERT
268 _visited_for_critical_count = false;
269 #endif
271 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
272 _suspend_flags = 0;
274 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
275 _hashStateX = os::random() ;
276 _hashStateY = 842502087 ;
277 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
278 _hashStateW = 273326509 ;
280 _OnTrap = 0 ;
281 _schedctl = NULL ;
282 _Stalled = 0 ;
283 _TypeTag = 0x2BAD ;
285 // Many of the following fields are effectively final - immutable
286 // Note that nascent threads can't use the Native Monitor-Mutex
287 // construct until the _MutexEvent is initialized ...
288 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
289 // we might instead use a stack of ParkEvents that we could provision on-demand.
290 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
291 // and ::Release()
292 _ParkEvent = ParkEvent::Allocate (this) ;
293 _SleepEvent = ParkEvent::Allocate (this) ;
294 _MutexEvent = ParkEvent::Allocate (this) ;
295 _MuxEvent = ParkEvent::Allocate (this) ;
297 #ifdef CHECK_UNHANDLED_OOPS
298 if (CheckUnhandledOops) {
299 _unhandled_oops = new UnhandledOops(this);
300 }
301 #endif // CHECK_UNHANDLED_OOPS
302 #ifdef ASSERT
303 if (UseBiasedLocking) {
304 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
305 assert(this == _real_malloc_address ||
306 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
307 "bug in forced alignment of thread objects");
308 }
309 #endif /* ASSERT */
310 }
312 void Thread::initialize_thread_local_storage() {
313 // Note: Make sure this method only calls
314 // non-blocking operations. Otherwise, it might not work
315 // with the thread-startup/safepoint interaction.
317 // During Java thread startup, safepoint code should allow this
318 // method to complete because it may need to allocate memory to
319 // store information for the new thread.
321 // initialize structure dependent on thread local storage
322 ThreadLocalStorage::set_thread(this);
323 }
325 void Thread::record_stack_base_and_size() {
326 set_stack_base(os::current_stack_base());
327 set_stack_size(os::current_stack_size());
328 if (is_Java_thread()) {
329 ((JavaThread*) this)->set_stack_overflow_limit();
330 }
331 // CR 7190089: on Solaris, primordial thread's stack is adjusted
332 // in initialize_thread(). Without the adjustment, stack size is
333 // incorrect if stack is set to unlimited (ulimit -s unlimited).
334 // So far, only Solaris has real implementation of initialize_thread().
335 //
336 // set up any platform-specific state.
337 os::initialize_thread(this);
339 #if INCLUDE_NMT
340 // record thread's native stack, stack grows downward
341 address stack_low_addr = stack_base() - stack_size();
342 MemTracker::record_thread_stack(stack_low_addr, stack_size());
343 #endif // INCLUDE_NMT
344 }
347 Thread::~Thread() {
348 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
349 ObjectSynchronizer::omFlush (this) ;
351 EVENT_THREAD_DESTRUCT(this);
353 // stack_base can be NULL if the thread is never started or exited before
354 // record_stack_base_and_size called. Although, we would like to ensure
355 // that all started threads do call record_stack_base_and_size(), there is
356 // not proper way to enforce that.
357 #if INCLUDE_NMT
358 if (_stack_base != NULL) {
359 address low_stack_addr = stack_base() - stack_size();
360 MemTracker::release_thread_stack(low_stack_addr, stack_size());
361 #ifdef ASSERT
362 set_stack_base(NULL);
363 #endif
364 }
365 #endif // INCLUDE_NMT
367 // deallocate data structures
368 delete resource_area();
369 // since the handle marks are using the handle area, we have to deallocated the root
370 // handle mark before deallocating the thread's handle area,
371 assert(last_handle_mark() != NULL, "check we have an element");
372 delete last_handle_mark();
373 assert(last_handle_mark() == NULL, "check we have reached the end");
375 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
376 // We NULL out the fields for good hygiene.
377 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
378 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
379 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
380 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
382 delete handle_area();
383 delete metadata_handles();
385 // osthread() can be NULL, if creation of thread failed.
386 if (osthread() != NULL) os::free_thread(osthread());
388 delete _SR_lock;
390 // clear thread local storage if the Thread is deleting itself
391 if (this == Thread::current()) {
392 ThreadLocalStorage::set_thread(NULL);
393 } else {
394 // In the case where we're not the current thread, invalidate all the
395 // caches in case some code tries to get the current thread or the
396 // thread that was destroyed, and gets stale information.
397 ThreadLocalStorage::invalidate_all();
398 }
399 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
400 }
402 // NOTE: dummy function for assertion purpose.
403 void Thread::run() {
404 ShouldNotReachHere();
405 }
407 #ifdef ASSERT
408 // Private method to check for dangling thread pointer
409 void check_for_dangling_thread_pointer(Thread *thread) {
410 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
411 "possibility of dangling Thread pointer");
412 }
413 #endif
416 #ifndef PRODUCT
417 // Tracing method for basic thread operations
418 void Thread::trace(const char* msg, const Thread* const thread) {
419 if (!TraceThreadEvents) return;
420 ResourceMark rm;
421 ThreadCritical tc;
422 const char *name = "non-Java thread";
423 int prio = -1;
424 if (thread->is_Java_thread()
425 && !thread->is_Compiler_thread()) {
426 // The Threads_lock must be held to get information about
427 // this thread but may not be in some situations when
428 // tracing thread events.
429 bool release_Threads_lock = false;
430 if (!Threads_lock->owned_by_self()) {
431 Threads_lock->lock();
432 release_Threads_lock = true;
433 }
434 JavaThread* jt = (JavaThread *)thread;
435 name = (char *)jt->get_thread_name();
436 oop thread_oop = jt->threadObj();
437 if (thread_oop != NULL) {
438 prio = java_lang_Thread::priority(thread_oop);
439 }
440 if (release_Threads_lock) {
441 Threads_lock->unlock();
442 }
443 }
444 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
445 }
446 #endif
449 ThreadPriority Thread::get_priority(const Thread* const thread) {
450 trace("get priority", thread);
451 ThreadPriority priority;
452 // Can return an error!
453 (void)os::get_priority(thread, priority);
454 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
455 return priority;
456 }
458 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
459 trace("set priority", thread);
460 debug_only(check_for_dangling_thread_pointer(thread);)
461 // Can return an error!
462 (void)os::set_priority(thread, priority);
463 }
466 void Thread::start(Thread* thread) {
467 trace("start", thread);
468 // Start is different from resume in that its safety is guaranteed by context or
469 // being called from a Java method synchronized on the Thread object.
470 if (!DisableStartThread) {
471 if (thread->is_Java_thread()) {
472 // Initialize the thread state to RUNNABLE before starting this thread.
473 // Can not set it after the thread started because we do not know the
474 // exact thread state at that time. It could be in MONITOR_WAIT or
475 // in SLEEPING or some other state.
476 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
477 java_lang_Thread::RUNNABLE);
478 }
479 os::start_thread(thread);
480 }
481 }
483 // Enqueue a VM_Operation to do the job for us - sometime later
484 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
485 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
486 VMThread::execute(vm_stop);
487 }
490 //
491 // Check if an external suspend request has completed (or has been
492 // cancelled). Returns true if the thread is externally suspended and
493 // false otherwise.
494 //
495 // The bits parameter returns information about the code path through
496 // the routine. Useful for debugging:
497 //
498 // set in is_ext_suspend_completed():
499 // 0x00000001 - routine was entered
500 // 0x00000010 - routine return false at end
501 // 0x00000100 - thread exited (return false)
502 // 0x00000200 - suspend request cancelled (return false)
503 // 0x00000400 - thread suspended (return true)
504 // 0x00001000 - thread is in a suspend equivalent state (return true)
505 // 0x00002000 - thread is native and walkable (return true)
506 // 0x00004000 - thread is native_trans and walkable (needed retry)
507 //
508 // set in wait_for_ext_suspend_completion():
509 // 0x00010000 - routine was entered
510 // 0x00020000 - suspend request cancelled before loop (return false)
511 // 0x00040000 - thread suspended before loop (return true)
512 // 0x00080000 - suspend request cancelled in loop (return false)
513 // 0x00100000 - thread suspended in loop (return true)
514 // 0x00200000 - suspend not completed during retry loop (return false)
515 //
517 // Helper class for tracing suspend wait debug bits.
518 //
519 // 0x00000100 indicates that the target thread exited before it could
520 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
521 // 0x00080000 each indicate a cancelled suspend request so they don't
522 // count as wait failures either.
523 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
525 class TraceSuspendDebugBits : public StackObj {
526 private:
527 JavaThread * jt;
528 bool is_wait;
529 bool called_by_wait; // meaningful when !is_wait
530 uint32_t * bits;
532 public:
533 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
534 uint32_t *_bits) {
535 jt = _jt;
536 is_wait = _is_wait;
537 called_by_wait = _called_by_wait;
538 bits = _bits;
539 }
541 ~TraceSuspendDebugBits() {
542 if (!is_wait) {
543 #if 1
544 // By default, don't trace bits for is_ext_suspend_completed() calls.
545 // That trace is very chatty.
546 return;
547 #else
548 if (!called_by_wait) {
549 // If tracing for is_ext_suspend_completed() is enabled, then only
550 // trace calls to it from wait_for_ext_suspend_completion()
551 return;
552 }
553 #endif
554 }
556 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
557 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
558 MutexLocker ml(Threads_lock); // needed for get_thread_name()
559 ResourceMark rm;
561 tty->print_cr(
562 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
563 jt->get_thread_name(), *bits);
565 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
566 }
567 }
568 }
569 };
570 #undef DEBUG_FALSE_BITS
573 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
574 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
576 bool did_trans_retry = false; // only do thread_in_native_trans retry once
577 bool do_trans_retry; // flag to force the retry
579 *bits |= 0x00000001;
581 do {
582 do_trans_retry = false;
584 if (is_exiting()) {
585 // Thread is in the process of exiting. This is always checked
586 // first to reduce the risk of dereferencing a freed JavaThread.
587 *bits |= 0x00000100;
588 return false;
589 }
591 if (!is_external_suspend()) {
592 // Suspend request is cancelled. This is always checked before
593 // is_ext_suspended() to reduce the risk of a rogue resume
594 // confusing the thread that made the suspend request.
595 *bits |= 0x00000200;
596 return false;
597 }
599 if (is_ext_suspended()) {
600 // thread is suspended
601 *bits |= 0x00000400;
602 return true;
603 }
605 // Now that we no longer do hard suspends of threads running
606 // native code, the target thread can be changing thread state
607 // while we are in this routine:
608 //
609 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
610 //
611 // We save a copy of the thread state as observed at this moment
612 // and make our decision about suspend completeness based on the
613 // copy. This closes the race where the thread state is seen as
614 // _thread_in_native_trans in the if-thread_blocked check, but is
615 // seen as _thread_blocked in if-thread_in_native_trans check.
616 JavaThreadState save_state = thread_state();
618 if (save_state == _thread_blocked && is_suspend_equivalent()) {
619 // If the thread's state is _thread_blocked and this blocking
620 // condition is known to be equivalent to a suspend, then we can
621 // consider the thread to be externally suspended. This means that
622 // the code that sets _thread_blocked has been modified to do
623 // self-suspension if the blocking condition releases. We also
624 // used to check for CONDVAR_WAIT here, but that is now covered by
625 // the _thread_blocked with self-suspension check.
626 //
627 // Return true since we wouldn't be here unless there was still an
628 // external suspend request.
629 *bits |= 0x00001000;
630 return true;
631 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
632 // Threads running native code will self-suspend on native==>VM/Java
633 // transitions. If its stack is walkable (should always be the case
634 // unless this function is called before the actual java_suspend()
635 // call), then the wait is done.
636 *bits |= 0x00002000;
637 return true;
638 } else if (!called_by_wait && !did_trans_retry &&
639 save_state == _thread_in_native_trans &&
640 frame_anchor()->walkable()) {
641 // The thread is transitioning from thread_in_native to another
642 // thread state. check_safepoint_and_suspend_for_native_trans()
643 // will force the thread to self-suspend. If it hasn't gotten
644 // there yet we may have caught the thread in-between the native
645 // code check above and the self-suspend. Lucky us. If we were
646 // called by wait_for_ext_suspend_completion(), then it
647 // will be doing the retries so we don't have to.
648 //
649 // Since we use the saved thread state in the if-statement above,
650 // there is a chance that the thread has already transitioned to
651 // _thread_blocked by the time we get here. In that case, we will
652 // make a single unnecessary pass through the logic below. This
653 // doesn't hurt anything since we still do the trans retry.
655 *bits |= 0x00004000;
657 // Once the thread leaves thread_in_native_trans for another
658 // thread state, we break out of this retry loop. We shouldn't
659 // need this flag to prevent us from getting back here, but
660 // sometimes paranoia is good.
661 did_trans_retry = true;
663 // We wait for the thread to transition to a more usable state.
664 for (int i = 1; i <= SuspendRetryCount; i++) {
665 // We used to do an "os::yield_all(i)" call here with the intention
666 // that yielding would increase on each retry. However, the parameter
667 // is ignored on Linux which means the yield didn't scale up. Waiting
668 // on the SR_lock below provides a much more predictable scale up for
669 // the delay. It also provides a simple/direct point to check for any
670 // safepoint requests from the VMThread
672 // temporarily drops SR_lock while doing wait with safepoint check
673 // (if we're a JavaThread - the WatcherThread can also call this)
674 // and increase delay with each retry
675 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
677 // check the actual thread state instead of what we saved above
678 if (thread_state() != _thread_in_native_trans) {
679 // the thread has transitioned to another thread state so
680 // try all the checks (except this one) one more time.
681 do_trans_retry = true;
682 break;
683 }
684 } // end retry loop
687 }
688 } while (do_trans_retry);
690 *bits |= 0x00000010;
691 return false;
692 }
694 //
695 // Wait for an external suspend request to complete (or be cancelled).
696 // Returns true if the thread is externally suspended and false otherwise.
697 //
698 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
699 uint32_t *bits) {
700 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
701 false /* !called_by_wait */, bits);
703 // local flag copies to minimize SR_lock hold time
704 bool is_suspended;
705 bool pending;
706 uint32_t reset_bits;
708 // set a marker so is_ext_suspend_completed() knows we are the caller
709 *bits |= 0x00010000;
711 // We use reset_bits to reinitialize the bits value at the top of
712 // each retry loop. This allows the caller to make use of any
713 // unused bits for their own marking purposes.
714 reset_bits = *bits;
716 {
717 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
718 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
719 delay, bits);
720 pending = is_external_suspend();
721 }
722 // must release SR_lock to allow suspension to complete
724 if (!pending) {
725 // A cancelled suspend request is the only false return from
726 // is_ext_suspend_completed() that keeps us from entering the
727 // retry loop.
728 *bits |= 0x00020000;
729 return false;
730 }
732 if (is_suspended) {
733 *bits |= 0x00040000;
734 return true;
735 }
737 for (int i = 1; i <= retries; i++) {
738 *bits = reset_bits; // reinit to only track last retry
740 // We used to do an "os::yield_all(i)" call here with the intention
741 // that yielding would increase on each retry. However, the parameter
742 // is ignored on Linux which means the yield didn't scale up. Waiting
743 // on the SR_lock below provides a much more predictable scale up for
744 // the delay. It also provides a simple/direct point to check for any
745 // safepoint requests from the VMThread
747 {
748 MutexLocker ml(SR_lock());
749 // wait with safepoint check (if we're a JavaThread - the WatcherThread
750 // can also call this) and increase delay with each retry
751 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
753 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
754 delay, bits);
756 // It is possible for the external suspend request to be cancelled
757 // (by a resume) before the actual suspend operation is completed.
758 // Refresh our local copy to see if we still need to wait.
759 pending = is_external_suspend();
760 }
762 if (!pending) {
763 // A cancelled suspend request is the only false return from
764 // is_ext_suspend_completed() that keeps us from staying in the
765 // retry loop.
766 *bits |= 0x00080000;
767 return false;
768 }
770 if (is_suspended) {
771 *bits |= 0x00100000;
772 return true;
773 }
774 } // end retry loop
776 // thread did not suspend after all our retries
777 *bits |= 0x00200000;
778 return false;
779 }
781 #ifndef PRODUCT
782 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
784 // This should not need to be atomic as the only way for simultaneous
785 // updates is via interrupts. Even then this should be rare or non-existant
786 // and we don't care that much anyway.
788 int index = _jmp_ring_index;
789 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
790 _jmp_ring[index]._target = (intptr_t) target;
791 _jmp_ring[index]._instruction = (intptr_t) instr;
792 _jmp_ring[index]._file = file;
793 _jmp_ring[index]._line = line;
794 }
795 #endif /* PRODUCT */
797 // Called by flat profiler
798 // Callers have already called wait_for_ext_suspend_completion
799 // The assertion for that is currently too complex to put here:
800 bool JavaThread::profile_last_Java_frame(frame* _fr) {
801 bool gotframe = false;
802 // self suspension saves needed state.
803 if (has_last_Java_frame() && _anchor.walkable()) {
804 *_fr = pd_last_frame();
805 gotframe = true;
806 }
807 return gotframe;
808 }
810 void Thread::interrupt(Thread* thread) {
811 trace("interrupt", thread);
812 debug_only(check_for_dangling_thread_pointer(thread);)
813 os::interrupt(thread);
814 }
816 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
817 trace("is_interrupted", thread);
818 debug_only(check_for_dangling_thread_pointer(thread);)
819 // Note: If clear_interrupted==false, this simply fetches and
820 // returns the value of the field osthread()->interrupted().
821 return os::is_interrupted(thread, clear_interrupted);
822 }
825 // GC Support
826 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
827 jint thread_parity = _oops_do_parity;
828 if (thread_parity != strong_roots_parity) {
829 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
830 if (res == thread_parity) {
831 return true;
832 } else {
833 guarantee(res == strong_roots_parity, "Or else what?");
834 assert(SharedHeap::heap()->workers()->active_workers() > 0,
835 "Should only fail when parallel.");
836 return false;
837 }
838 }
839 assert(SharedHeap::heap()->workers()->active_workers() > 0,
840 "Should only fail when parallel.");
841 return false;
842 }
844 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
845 active_handles()->oops_do(f);
846 // Do oop for ThreadShadow
847 f->do_oop((oop*)&_pending_exception);
848 handle_area()->oops_do(f);
849 }
851 void Thread::nmethods_do(CodeBlobClosure* cf) {
852 // no nmethods in a generic thread...
853 }
855 void Thread::metadata_do(void f(Metadata*)) {
856 if (metadata_handles() != NULL) {
857 for (int i = 0; i< metadata_handles()->length(); i++) {
858 f(metadata_handles()->at(i));
859 }
860 }
861 }
863 void Thread::print_on(outputStream* st) const {
864 // get_priority assumes osthread initialized
865 if (osthread() != NULL) {
866 int os_prio;
867 if (os::get_native_priority(this, &os_prio) == OS_OK) {
868 st->print("os_prio=%d ", os_prio);
869 }
870 st->print("tid=" INTPTR_FORMAT " ", this);
871 ext().print_on(st);
872 osthread()->print_on(st);
873 }
874 debug_only(if (WizardMode) print_owned_locks_on(st);)
875 }
877 // Thread::print_on_error() is called by fatal error handler. Don't use
878 // any lock or allocate memory.
879 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
880 if (is_VM_thread()) st->print("VMThread");
881 else if (is_Compiler_thread()) st->print("CompilerThread");
882 else if (is_Java_thread()) st->print("JavaThread");
883 else if (is_GC_task_thread()) st->print("GCTaskThread");
884 else if (is_Watcher_thread()) st->print("WatcherThread");
885 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
886 else st->print("Thread");
888 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
889 _stack_base - _stack_size, _stack_base);
891 if (osthread()) {
892 st->print(" [id=%d]", osthread()->thread_id());
893 }
894 }
896 #ifdef ASSERT
897 void Thread::print_owned_locks_on(outputStream* st) const {
898 Monitor *cur = _owned_locks;
899 if (cur == NULL) {
900 st->print(" (no locks) ");
901 } else {
902 st->print_cr(" Locks owned:");
903 while(cur) {
904 cur->print_on(st);
905 cur = cur->next();
906 }
907 }
908 }
910 static int ref_use_count = 0;
912 bool Thread::owns_locks_but_compiled_lock() const {
913 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
914 if (cur != Compile_lock) return true;
915 }
916 return false;
917 }
920 #endif
922 #ifndef PRODUCT
924 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
925 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
926 // no threads which allow_vm_block's are held
927 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
928 // Check if current thread is allowed to block at a safepoint
929 if (!(_allow_safepoint_count == 0))
930 fatal("Possible safepoint reached by thread that does not allow it");
931 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
932 fatal("LEAF method calling lock?");
933 }
935 #ifdef ASSERT
936 if (potential_vm_operation && is_Java_thread()
937 && !Universe::is_bootstrapping()) {
938 // Make sure we do not hold any locks that the VM thread also uses.
939 // This could potentially lead to deadlocks
940 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
941 // Threads_lock is special, since the safepoint synchronization will not start before this is
942 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
943 // since it is used to transfer control between JavaThreads and the VMThread
944 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
945 if ( (cur->allow_vm_block() &&
946 cur != Threads_lock &&
947 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
948 cur != VMOperationRequest_lock &&
949 cur != VMOperationQueue_lock) ||
950 cur->rank() == Mutex::special) {
951 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
952 }
953 }
954 }
956 if (GCALotAtAllSafepoints) {
957 // We could enter a safepoint here and thus have a gc
958 InterfaceSupport::check_gc_alot();
959 }
960 #endif
961 }
962 #endif
964 bool Thread::is_in_stack(address adr) const {
965 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
966 address end = os::current_stack_pointer();
967 // Allow non Java threads to call this without stack_base
968 if (_stack_base == NULL) return true;
969 if (stack_base() >= adr && adr >= end) return true;
971 return false;
972 }
975 bool Thread::is_in_usable_stack(address adr) const {
976 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
977 size_t usable_stack_size = _stack_size - stack_guard_size;
979 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
980 }
983 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
984 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
985 // used for compilation in the future. If that change is made, the need for these methods
986 // should be revisited, and they should be removed if possible.
988 bool Thread::is_lock_owned(address adr) const {
989 return on_local_stack(adr);
990 }
992 bool Thread::set_as_starting_thread() {
993 // NOTE: this must be called inside the main thread.
994 return os::create_main_thread((JavaThread*)this);
995 }
997 static void initialize_class(Symbol* class_name, TRAPS) {
998 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
999 InstanceKlass::cast(klass)->initialize(CHECK);
1000 }
1003 // Creates the initial ThreadGroup
1004 static Handle create_initial_thread_group(TRAPS) {
1005 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1006 instanceKlassHandle klass (THREAD, k);
1008 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1009 {
1010 JavaValue result(T_VOID);
1011 JavaCalls::call_special(&result,
1012 system_instance,
1013 klass,
1014 vmSymbols::object_initializer_name(),
1015 vmSymbols::void_method_signature(),
1016 CHECK_NH);
1017 }
1018 Universe::set_system_thread_group(system_instance());
1020 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1021 {
1022 JavaValue result(T_VOID);
1023 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1024 JavaCalls::call_special(&result,
1025 main_instance,
1026 klass,
1027 vmSymbols::object_initializer_name(),
1028 vmSymbols::threadgroup_string_void_signature(),
1029 system_instance,
1030 string,
1031 CHECK_NH);
1032 }
1033 return main_instance;
1034 }
1036 // Creates the initial Thread
1037 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1038 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1039 instanceKlassHandle klass (THREAD, k);
1040 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1042 java_lang_Thread::set_thread(thread_oop(), thread);
1043 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1044 thread->set_threadObj(thread_oop());
1046 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1048 JavaValue result(T_VOID);
1049 JavaCalls::call_special(&result, thread_oop,
1050 klass,
1051 vmSymbols::object_initializer_name(),
1052 vmSymbols::threadgroup_string_void_signature(),
1053 thread_group,
1054 string,
1055 CHECK_NULL);
1056 return thread_oop();
1057 }
1059 static void call_initializeSystemClass(TRAPS) {
1060 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1061 instanceKlassHandle klass (THREAD, k);
1063 JavaValue result(T_VOID);
1064 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1065 vmSymbols::void_method_signature(), CHECK);
1066 }
1068 char java_runtime_name[128] = "";
1069 char java_runtime_version[128] = "";
1071 // extract the JRE name from sun.misc.Version.java_runtime_name
1072 static const char* get_java_runtime_name(TRAPS) {
1073 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1074 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1075 fieldDescriptor fd;
1076 bool found = k != NULL &&
1077 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1078 vmSymbols::string_signature(), &fd);
1079 if (found) {
1080 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1081 if (name_oop == NULL)
1082 return NULL;
1083 const char* name = java_lang_String::as_utf8_string(name_oop,
1084 java_runtime_name,
1085 sizeof(java_runtime_name));
1086 return name;
1087 } else {
1088 return NULL;
1089 }
1090 }
1092 // extract the JRE version from sun.misc.Version.java_runtime_version
1093 static const char* get_java_runtime_version(TRAPS) {
1094 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1095 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1096 fieldDescriptor fd;
1097 bool found = k != NULL &&
1098 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1099 vmSymbols::string_signature(), &fd);
1100 if (found) {
1101 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1102 if (name_oop == NULL)
1103 return NULL;
1104 const char* name = java_lang_String::as_utf8_string(name_oop,
1105 java_runtime_version,
1106 sizeof(java_runtime_version));
1107 return name;
1108 } else {
1109 return NULL;
1110 }
1111 }
1113 // General purpose hook into Java code, run once when the VM is initialized.
1114 // The Java library method itself may be changed independently from the VM.
1115 static void call_postVMInitHook(TRAPS) {
1116 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1117 instanceKlassHandle klass (THREAD, k);
1118 if (klass.not_null()) {
1119 JavaValue result(T_VOID);
1120 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1121 vmSymbols::void_method_signature(),
1122 CHECK);
1123 }
1124 }
1126 static void reset_vm_info_property(TRAPS) {
1127 // the vm info string
1128 ResourceMark rm(THREAD);
1129 const char *vm_info = VM_Version::vm_info_string();
1131 // java.lang.System class
1132 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1133 instanceKlassHandle klass (THREAD, k);
1135 // setProperty arguments
1136 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1137 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1139 // return value
1140 JavaValue r(T_OBJECT);
1142 // public static String setProperty(String key, String value);
1143 JavaCalls::call_static(&r,
1144 klass,
1145 vmSymbols::setProperty_name(),
1146 vmSymbols::string_string_string_signature(),
1147 key_str,
1148 value_str,
1149 CHECK);
1150 }
1153 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1154 assert(thread_group.not_null(), "thread group should be specified");
1155 assert(threadObj() == NULL, "should only create Java thread object once");
1157 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1158 instanceKlassHandle klass (THREAD, k);
1159 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1161 java_lang_Thread::set_thread(thread_oop(), this);
1162 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1163 set_threadObj(thread_oop());
1165 JavaValue result(T_VOID);
1166 if (thread_name != NULL) {
1167 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1168 // Thread gets assigned specified name and null target
1169 JavaCalls::call_special(&result,
1170 thread_oop,
1171 klass,
1172 vmSymbols::object_initializer_name(),
1173 vmSymbols::threadgroup_string_void_signature(),
1174 thread_group, // Argument 1
1175 name, // Argument 2
1176 THREAD);
1177 } else {
1178 // Thread gets assigned name "Thread-nnn" and null target
1179 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1180 JavaCalls::call_special(&result,
1181 thread_oop,
1182 klass,
1183 vmSymbols::object_initializer_name(),
1184 vmSymbols::threadgroup_runnable_void_signature(),
1185 thread_group, // Argument 1
1186 Handle(), // Argument 2
1187 THREAD);
1188 }
1191 if (daemon) {
1192 java_lang_Thread::set_daemon(thread_oop());
1193 }
1195 if (HAS_PENDING_EXCEPTION) {
1196 return;
1197 }
1199 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1200 Handle threadObj(this, this->threadObj());
1202 JavaCalls::call_special(&result,
1203 thread_group,
1204 group,
1205 vmSymbols::add_method_name(),
1206 vmSymbols::thread_void_signature(),
1207 threadObj, // Arg 1
1208 THREAD);
1211 }
1213 // NamedThread -- non-JavaThread subclasses with multiple
1214 // uniquely named instances should derive from this.
1215 NamedThread::NamedThread() : Thread() {
1216 _name = NULL;
1217 _processed_thread = NULL;
1218 }
1220 NamedThread::~NamedThread() {
1221 if (_name != NULL) {
1222 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1223 _name = NULL;
1224 }
1225 }
1227 void NamedThread::set_name(const char* format, ...) {
1228 guarantee(_name == NULL, "Only get to set name once.");
1229 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1230 guarantee(_name != NULL, "alloc failure");
1231 va_list ap;
1232 va_start(ap, format);
1233 jio_vsnprintf(_name, max_name_len, format, ap);
1234 va_end(ap);
1235 }
1237 // ======= WatcherThread ========
1239 // The watcher thread exists to simulate timer interrupts. It should
1240 // be replaced by an abstraction over whatever native support for
1241 // timer interrupts exists on the platform.
1243 WatcherThread* WatcherThread::_watcher_thread = NULL;
1244 bool WatcherThread::_startable = false;
1245 volatile bool WatcherThread::_should_terminate = false;
1247 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1248 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1249 if (os::create_thread(this, os::watcher_thread)) {
1250 _watcher_thread = this;
1252 // Set the watcher thread to the highest OS priority which should not be
1253 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1254 // is created. The only normal thread using this priority is the reference
1255 // handler thread, which runs for very short intervals only.
1256 // If the VMThread's priority is not lower than the WatcherThread profiling
1257 // will be inaccurate.
1258 os::set_priority(this, MaxPriority);
1259 if (!DisableStartThread) {
1260 os::start_thread(this);
1261 }
1262 }
1263 }
1265 int WatcherThread::sleep() const {
1266 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1268 // remaining will be zero if there are no tasks,
1269 // causing the WatcherThread to sleep until a task is
1270 // enrolled
1271 int remaining = PeriodicTask::time_to_wait();
1272 int time_slept = 0;
1274 // we expect this to timeout - we only ever get unparked when
1275 // we should terminate or when a new task has been enrolled
1276 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1278 jlong time_before_loop = os::javaTimeNanos();
1280 for (;;) {
1281 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1282 jlong now = os::javaTimeNanos();
1284 if (remaining == 0) {
1285 // if we didn't have any tasks we could have waited for a long time
1286 // consider the time_slept zero and reset time_before_loop
1287 time_slept = 0;
1288 time_before_loop = now;
1289 } else {
1290 // need to recalulate since we might have new tasks in _tasks
1291 time_slept = (int) ((now - time_before_loop) / 1000000);
1292 }
1294 // Change to task list or spurious wakeup of some kind
1295 if (timedout || _should_terminate) {
1296 break;
1297 }
1299 remaining = PeriodicTask::time_to_wait();
1300 if (remaining == 0) {
1301 // Last task was just disenrolled so loop around and wait until
1302 // another task gets enrolled
1303 continue;
1304 }
1306 remaining -= time_slept;
1307 if (remaining <= 0)
1308 break;
1309 }
1311 return time_slept;
1312 }
1314 void WatcherThread::run() {
1315 assert(this == watcher_thread(), "just checking");
1317 this->record_stack_base_and_size();
1318 this->initialize_thread_local_storage();
1319 this->set_native_thread_name(this->name());
1320 this->set_active_handles(JNIHandleBlock::allocate_block());
1321 while(!_should_terminate) {
1322 assert(watcher_thread() == Thread::current(), "thread consistency check");
1323 assert(watcher_thread() == this, "thread consistency check");
1325 // Calculate how long it'll be until the next PeriodicTask work
1326 // should be done, and sleep that amount of time.
1327 int time_waited = sleep();
1329 if (is_error_reported()) {
1330 // A fatal error has happened, the error handler(VMError::report_and_die)
1331 // should abort JVM after creating an error log file. However in some
1332 // rare cases, the error handler itself might deadlock. Here we try to
1333 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1334 //
1335 // This code is in WatcherThread because WatcherThread wakes up
1336 // periodically so the fatal error handler doesn't need to do anything;
1337 // also because the WatcherThread is less likely to crash than other
1338 // threads.
1340 for (;;) {
1341 if (!ShowMessageBoxOnError
1342 && (OnError == NULL || OnError[0] == '\0')
1343 && Arguments::abort_hook() == NULL) {
1344 os::sleep(this, 2 * 60 * 1000, false);
1345 fdStream err(defaultStream::output_fd());
1346 err.print_raw_cr("# [ timer expired, abort... ]");
1347 // skip atexit/vm_exit/vm_abort hooks
1348 os::die();
1349 }
1351 // Wake up 5 seconds later, the fatal handler may reset OnError or
1352 // ShowMessageBoxOnError when it is ready to abort.
1353 os::sleep(this, 5 * 1000, false);
1354 }
1355 }
1357 PeriodicTask::real_time_tick(time_waited);
1358 }
1360 // Signal that it is terminated
1361 {
1362 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1363 _watcher_thread = NULL;
1364 Terminator_lock->notify();
1365 }
1367 // Thread destructor usually does this..
1368 ThreadLocalStorage::set_thread(NULL);
1369 }
1371 void WatcherThread::start() {
1372 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1374 if (watcher_thread() == NULL && _startable) {
1375 _should_terminate = false;
1376 // Create the single instance of WatcherThread
1377 new WatcherThread();
1378 }
1379 }
1381 void WatcherThread::make_startable() {
1382 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1383 _startable = true;
1384 }
1386 void WatcherThread::stop() {
1387 {
1388 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1389 _should_terminate = true;
1390 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1392 WatcherThread* watcher = watcher_thread();
1393 if (watcher != NULL)
1394 watcher->unpark();
1395 }
1397 // it is ok to take late safepoints here, if needed
1398 MutexLocker mu(Terminator_lock);
1400 while(watcher_thread() != NULL) {
1401 // This wait should make safepoint checks, wait without a timeout,
1402 // and wait as a suspend-equivalent condition.
1403 //
1404 // Note: If the FlatProfiler is running, then this thread is waiting
1405 // for the WatcherThread to terminate and the WatcherThread, via the
1406 // FlatProfiler task, is waiting for the external suspend request on
1407 // this thread to complete. wait_for_ext_suspend_completion() will
1408 // eventually timeout, but that takes time. Making this wait a
1409 // suspend-equivalent condition solves that timeout problem.
1410 //
1411 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1412 Mutex::_as_suspend_equivalent_flag);
1413 }
1414 }
1416 void WatcherThread::unpark() {
1417 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1418 PeriodicTask_lock->notify();
1419 }
1421 void WatcherThread::print_on(outputStream* st) const {
1422 st->print("\"%s\" ", name());
1423 Thread::print_on(st);
1424 st->cr();
1425 }
1427 // ======= JavaThread ========
1429 // A JavaThread is a normal Java thread
1431 void JavaThread::initialize() {
1432 // Initialize fields
1434 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1435 set_claimed_par_id(UINT_MAX);
1437 set_saved_exception_pc(NULL);
1438 set_threadObj(NULL);
1439 _anchor.clear();
1440 set_entry_point(NULL);
1441 set_jni_functions(jni_functions());
1442 set_callee_target(NULL);
1443 set_vm_result(NULL);
1444 set_vm_result_2(NULL);
1445 set_vframe_array_head(NULL);
1446 set_vframe_array_last(NULL);
1447 set_deferred_locals(NULL);
1448 set_deopt_mark(NULL);
1449 set_deopt_nmethod(NULL);
1450 clear_must_deopt_id();
1451 set_monitor_chunks(NULL);
1452 set_next(NULL);
1453 set_thread_state(_thread_new);
1454 _terminated = _not_terminated;
1455 _privileged_stack_top = NULL;
1456 _array_for_gc = NULL;
1457 _suspend_equivalent = false;
1458 _in_deopt_handler = 0;
1459 _doing_unsafe_access = false;
1460 _stack_guard_state = stack_guard_unused;
1461 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1462 _exception_pc = 0;
1463 _exception_handler_pc = 0;
1464 _is_method_handle_return = 0;
1465 _jvmti_thread_state= NULL;
1466 _should_post_on_exceptions_flag = JNI_FALSE;
1467 _jvmti_get_loaded_classes_closure = NULL;
1468 _interp_only_mode = 0;
1469 _special_runtime_exit_condition = _no_async_condition;
1470 _pending_async_exception = NULL;
1471 _thread_stat = NULL;
1472 _thread_stat = new ThreadStatistics();
1473 _blocked_on_compilation = false;
1474 _jni_active_critical = 0;
1475 _pending_jni_exception_check_fn = NULL;
1476 _do_not_unlock_if_synchronized = false;
1477 _cached_monitor_info = NULL;
1478 _parker = Parker::Allocate(this) ;
1480 #ifndef PRODUCT
1481 _jmp_ring_index = 0;
1482 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1483 record_jump(NULL, NULL, NULL, 0);
1484 }
1485 #endif /* PRODUCT */
1487 set_thread_profiler(NULL);
1488 if (FlatProfiler::is_active()) {
1489 // This is where we would decide to either give each thread it's own profiler
1490 // or use one global one from FlatProfiler,
1491 // or up to some count of the number of profiled threads, etc.
1492 ThreadProfiler* pp = new ThreadProfiler();
1493 pp->engage();
1494 set_thread_profiler(pp);
1495 }
1497 // Setup safepoint state info for this thread
1498 ThreadSafepointState::create(this);
1500 debug_only(_java_call_counter = 0);
1502 // JVMTI PopFrame support
1503 _popframe_condition = popframe_inactive;
1504 _popframe_preserved_args = NULL;
1505 _popframe_preserved_args_size = 0;
1506 _frames_to_pop_failed_realloc = 0;
1508 pd_initialize();
1509 }
1511 #if INCLUDE_ALL_GCS
1512 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1513 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1514 #endif // INCLUDE_ALL_GCS
1516 JavaThread::JavaThread(bool is_attaching_via_jni) :
1517 Thread()
1518 #if INCLUDE_ALL_GCS
1519 , _satb_mark_queue(&_satb_mark_queue_set),
1520 _dirty_card_queue(&_dirty_card_queue_set)
1521 #endif // INCLUDE_ALL_GCS
1522 {
1523 initialize();
1524 if (is_attaching_via_jni) {
1525 _jni_attach_state = _attaching_via_jni;
1526 } else {
1527 _jni_attach_state = _not_attaching_via_jni;
1528 }
1529 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1530 }
1532 bool JavaThread::reguard_stack(address cur_sp) {
1533 if (_stack_guard_state != stack_guard_yellow_disabled) {
1534 return true; // Stack already guarded or guard pages not needed.
1535 }
1537 if (register_stack_overflow()) {
1538 // For those architectures which have separate register and
1539 // memory stacks, we must check the register stack to see if
1540 // it has overflowed.
1541 return false;
1542 }
1544 // Java code never executes within the yellow zone: the latter is only
1545 // there to provoke an exception during stack banging. If java code
1546 // is executing there, either StackShadowPages should be larger, or
1547 // some exception code in c1, c2 or the interpreter isn't unwinding
1548 // when it should.
1549 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1551 enable_stack_yellow_zone();
1552 return true;
1553 }
1555 bool JavaThread::reguard_stack(void) {
1556 return reguard_stack(os::current_stack_pointer());
1557 }
1560 void JavaThread::block_if_vm_exited() {
1561 if (_terminated == _vm_exited) {
1562 // _vm_exited is set at safepoint, and Threads_lock is never released
1563 // we will block here forever
1564 Threads_lock->lock_without_safepoint_check();
1565 ShouldNotReachHere();
1566 }
1567 }
1570 // Remove this ifdef when C1 is ported to the compiler interface.
1571 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1573 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1574 Thread()
1575 #if INCLUDE_ALL_GCS
1576 , _satb_mark_queue(&_satb_mark_queue_set),
1577 _dirty_card_queue(&_dirty_card_queue_set)
1578 #endif // INCLUDE_ALL_GCS
1579 {
1580 if (TraceThreadEvents) {
1581 tty->print_cr("creating thread %p", this);
1582 }
1583 initialize();
1584 _jni_attach_state = _not_attaching_via_jni;
1585 set_entry_point(entry_point);
1586 // Create the native thread itself.
1587 // %note runtime_23
1588 os::ThreadType thr_type = os::java_thread;
1589 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1590 os::java_thread;
1591 os::create_thread(this, thr_type, stack_sz);
1592 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1593 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1594 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1595 // the exception consists of creating the exception object & initializing it, initialization
1596 // will leave the VM via a JavaCall and then all locks must be unlocked).
1597 //
1598 // The thread is still suspended when we reach here. Thread must be explicit started
1599 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1600 // by calling Threads:add. The reason why this is not done here, is because the thread
1601 // object must be fully initialized (take a look at JVM_Start)
1602 }
1604 JavaThread::~JavaThread() {
1605 if (TraceThreadEvents) {
1606 tty->print_cr("terminate thread %p", this);
1607 }
1609 // JSR166 -- return the parker to the free list
1610 Parker::Release(_parker);
1611 _parker = NULL ;
1613 // Free any remaining previous UnrollBlock
1614 vframeArray* old_array = vframe_array_last();
1616 if (old_array != NULL) {
1617 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1618 old_array->set_unroll_block(NULL);
1619 delete old_info;
1620 delete old_array;
1621 }
1623 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1624 if (deferred != NULL) {
1625 // This can only happen if thread is destroyed before deoptimization occurs.
1626 assert(deferred->length() != 0, "empty array!");
1627 do {
1628 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1629 deferred->remove_at(0);
1630 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1631 delete dlv;
1632 } while (deferred->length() != 0);
1633 delete deferred;
1634 }
1636 // All Java related clean up happens in exit
1637 ThreadSafepointState::destroy(this);
1638 if (_thread_profiler != NULL) delete _thread_profiler;
1639 if (_thread_stat != NULL) delete _thread_stat;
1640 }
1643 // The first routine called by a new Java thread
1644 void JavaThread::run() {
1645 // initialize thread-local alloc buffer related fields
1646 this->initialize_tlab();
1648 // used to test validitity of stack trace backs
1649 this->record_base_of_stack_pointer();
1651 // Record real stack base and size.
1652 this->record_stack_base_and_size();
1654 // Initialize thread local storage; set before calling MutexLocker
1655 this->initialize_thread_local_storage();
1657 this->create_stack_guard_pages();
1659 this->cache_global_variables();
1661 // Thread is now sufficient initialized to be handled by the safepoint code as being
1662 // in the VM. Change thread state from _thread_new to _thread_in_vm
1663 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1665 assert(JavaThread::current() == this, "sanity check");
1666 assert(!Thread::current()->owns_locks(), "sanity check");
1668 DTRACE_THREAD_PROBE(start, this);
1670 // This operation might block. We call that after all safepoint checks for a new thread has
1671 // been completed.
1672 this->set_active_handles(JNIHandleBlock::allocate_block());
1674 if (JvmtiExport::should_post_thread_life()) {
1675 JvmtiExport::post_thread_start(this);
1676 }
1678 EventThreadStart event;
1679 if (event.should_commit()) {
1680 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1681 event.commit();
1682 }
1684 // We call another function to do the rest so we are sure that the stack addresses used
1685 // from there will be lower than the stack base just computed
1686 thread_main_inner();
1688 // Note, thread is no longer valid at this point!
1689 }
1692 void JavaThread::thread_main_inner() {
1693 assert(JavaThread::current() == this, "sanity check");
1694 assert(this->threadObj() != NULL, "just checking");
1696 // Execute thread entry point unless this thread has a pending exception
1697 // or has been stopped before starting.
1698 // Note: Due to JVM_StopThread we can have pending exceptions already!
1699 if (!this->has_pending_exception() &&
1700 !java_lang_Thread::is_stillborn(this->threadObj())) {
1701 {
1702 ResourceMark rm(this);
1703 this->set_native_thread_name(this->get_thread_name());
1704 }
1705 HandleMark hm(this);
1706 this->entry_point()(this, this);
1707 }
1709 DTRACE_THREAD_PROBE(stop, this);
1711 this->exit(false);
1712 delete this;
1713 }
1716 static void ensure_join(JavaThread* thread) {
1717 // We do not need to grap the Threads_lock, since we are operating on ourself.
1718 Handle threadObj(thread, thread->threadObj());
1719 assert(threadObj.not_null(), "java thread object must exist");
1720 ObjectLocker lock(threadObj, thread);
1721 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1722 thread->clear_pending_exception();
1723 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1724 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1725 // Clear the native thread instance - this makes isAlive return false and allows the join()
1726 // to complete once we've done the notify_all below
1727 java_lang_Thread::set_thread(threadObj(), NULL);
1728 lock.notify_all(thread);
1729 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1730 thread->clear_pending_exception();
1731 }
1734 // For any new cleanup additions, please check to see if they need to be applied to
1735 // cleanup_failed_attach_current_thread as well.
1736 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1737 assert(this == JavaThread::current(), "thread consistency check");
1739 HandleMark hm(this);
1740 Handle uncaught_exception(this, this->pending_exception());
1741 this->clear_pending_exception();
1742 Handle threadObj(this, this->threadObj());
1743 assert(threadObj.not_null(), "Java thread object should be created");
1745 if (get_thread_profiler() != NULL) {
1746 get_thread_profiler()->disengage();
1747 ResourceMark rm;
1748 get_thread_profiler()->print(get_thread_name());
1749 }
1752 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1753 {
1754 EXCEPTION_MARK;
1756 CLEAR_PENDING_EXCEPTION;
1757 }
1758 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1759 // has to be fixed by a runtime query method
1760 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1761 // JSR-166: change call from from ThreadGroup.uncaughtException to
1762 // java.lang.Thread.dispatchUncaughtException
1763 if (uncaught_exception.not_null()) {
1764 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1765 {
1766 EXCEPTION_MARK;
1767 // Check if the method Thread.dispatchUncaughtException() exists. If so
1768 // call it. Otherwise we have an older library without the JSR-166 changes,
1769 // so call ThreadGroup.uncaughtException()
1770 KlassHandle recvrKlass(THREAD, threadObj->klass());
1771 CallInfo callinfo;
1772 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1773 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1774 vmSymbols::dispatchUncaughtException_name(),
1775 vmSymbols::throwable_void_signature(),
1776 KlassHandle(), false, false, THREAD);
1777 CLEAR_PENDING_EXCEPTION;
1778 methodHandle method = callinfo.selected_method();
1779 if (method.not_null()) {
1780 JavaValue result(T_VOID);
1781 JavaCalls::call_virtual(&result,
1782 threadObj, thread_klass,
1783 vmSymbols::dispatchUncaughtException_name(),
1784 vmSymbols::throwable_void_signature(),
1785 uncaught_exception,
1786 THREAD);
1787 } else {
1788 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1789 JavaValue result(T_VOID);
1790 JavaCalls::call_virtual(&result,
1791 group, thread_group,
1792 vmSymbols::uncaughtException_name(),
1793 vmSymbols::thread_throwable_void_signature(),
1794 threadObj, // Arg 1
1795 uncaught_exception, // Arg 2
1796 THREAD);
1797 }
1798 if (HAS_PENDING_EXCEPTION) {
1799 ResourceMark rm(this);
1800 jio_fprintf(defaultStream::error_stream(),
1801 "\nException: %s thrown from the UncaughtExceptionHandler"
1802 " in thread \"%s\"\n",
1803 pending_exception()->klass()->external_name(),
1804 get_thread_name());
1805 CLEAR_PENDING_EXCEPTION;
1806 }
1807 }
1808 }
1810 // Called before the java thread exit since we want to read info
1811 // from java_lang_Thread object
1812 EventThreadEnd event;
1813 if (event.should_commit()) {
1814 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1815 event.commit();
1816 }
1818 // Call after last event on thread
1819 EVENT_THREAD_EXIT(this);
1821 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1822 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1823 // is deprecated anyhow.
1824 if (!is_Compiler_thread()) {
1825 int count = 3;
1826 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1827 EXCEPTION_MARK;
1828 JavaValue result(T_VOID);
1829 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1830 JavaCalls::call_virtual(&result,
1831 threadObj, thread_klass,
1832 vmSymbols::exit_method_name(),
1833 vmSymbols::void_method_signature(),
1834 THREAD);
1835 CLEAR_PENDING_EXCEPTION;
1836 }
1837 }
1838 // notify JVMTI
1839 if (JvmtiExport::should_post_thread_life()) {
1840 JvmtiExport::post_thread_end(this);
1841 }
1843 // We have notified the agents that we are exiting, before we go on,
1844 // we must check for a pending external suspend request and honor it
1845 // in order to not surprise the thread that made the suspend request.
1846 while (true) {
1847 {
1848 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1849 if (!is_external_suspend()) {
1850 set_terminated(_thread_exiting);
1851 ThreadService::current_thread_exiting(this);
1852 break;
1853 }
1854 // Implied else:
1855 // Things get a little tricky here. We have a pending external
1856 // suspend request, but we are holding the SR_lock so we
1857 // can't just self-suspend. So we temporarily drop the lock
1858 // and then self-suspend.
1859 }
1861 ThreadBlockInVM tbivm(this);
1862 java_suspend_self();
1864 // We're done with this suspend request, but we have to loop around
1865 // and check again. Eventually we will get SR_lock without a pending
1866 // external suspend request and will be able to mark ourselves as
1867 // exiting.
1868 }
1869 // no more external suspends are allowed at this point
1870 } else {
1871 // before_exit() has already posted JVMTI THREAD_END events
1872 }
1874 // Notify waiters on thread object. This has to be done after exit() is called
1875 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1876 // group should have the destroyed bit set before waiters are notified).
1877 ensure_join(this);
1878 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1880 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1881 // held by this thread must be released. A detach operation must only
1882 // get here if there are no Java frames on the stack. Therefore, any
1883 // owned monitors at this point MUST be JNI-acquired monitors which are
1884 // pre-inflated and in the monitor cache.
1885 //
1886 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1887 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1888 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1889 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1890 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1891 }
1893 // These things needs to be done while we are still a Java Thread. Make sure that thread
1894 // is in a consistent state, in case GC happens
1895 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1897 if (active_handles() != NULL) {
1898 JNIHandleBlock* block = active_handles();
1899 set_active_handles(NULL);
1900 JNIHandleBlock::release_block(block);
1901 }
1903 if (free_handle_block() != NULL) {
1904 JNIHandleBlock* block = free_handle_block();
1905 set_free_handle_block(NULL);
1906 JNIHandleBlock::release_block(block);
1907 }
1909 // These have to be removed while this is still a valid thread.
1910 remove_stack_guard_pages();
1912 if (UseTLAB) {
1913 tlab().make_parsable(true); // retire TLAB
1914 }
1916 if (JvmtiEnv::environments_might_exist()) {
1917 JvmtiExport::cleanup_thread(this);
1918 }
1920 // We must flush any deferred card marks before removing a thread from
1921 // the list of active threads.
1922 Universe::heap()->flush_deferred_store_barrier(this);
1923 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1925 #if INCLUDE_ALL_GCS
1926 // We must flush the G1-related buffers before removing a thread
1927 // from the list of active threads. We must do this after any deferred
1928 // card marks have been flushed (above) so that any entries that are
1929 // added to the thread's dirty card queue as a result are not lost.
1930 if (UseG1GC) {
1931 flush_barrier_queues();
1932 }
1933 #endif // INCLUDE_ALL_GCS
1935 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1936 Threads::remove(this);
1937 }
1939 #if INCLUDE_ALL_GCS
1940 // Flush G1-related queues.
1941 void JavaThread::flush_barrier_queues() {
1942 satb_mark_queue().flush();
1943 dirty_card_queue().flush();
1944 }
1946 void JavaThread::initialize_queues() {
1947 assert(!SafepointSynchronize::is_at_safepoint(),
1948 "we should not be at a safepoint");
1950 ObjPtrQueue& satb_queue = satb_mark_queue();
1951 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1952 // The SATB queue should have been constructed with its active
1953 // field set to false.
1954 assert(!satb_queue.is_active(), "SATB queue should not be active");
1955 assert(satb_queue.is_empty(), "SATB queue should be empty");
1956 // If we are creating the thread during a marking cycle, we should
1957 // set the active field of the SATB queue to true.
1958 if (satb_queue_set.is_active()) {
1959 satb_queue.set_active(true);
1960 }
1962 DirtyCardQueue& dirty_queue = dirty_card_queue();
1963 // The dirty card queue should have been constructed with its
1964 // active field set to true.
1965 assert(dirty_queue.is_active(), "dirty card queue should be active");
1966 }
1967 #endif // INCLUDE_ALL_GCS
1969 void JavaThread::cleanup_failed_attach_current_thread() {
1970 if (get_thread_profiler() != NULL) {
1971 get_thread_profiler()->disengage();
1972 ResourceMark rm;
1973 get_thread_profiler()->print(get_thread_name());
1974 }
1976 if (active_handles() != NULL) {
1977 JNIHandleBlock* block = active_handles();
1978 set_active_handles(NULL);
1979 JNIHandleBlock::release_block(block);
1980 }
1982 if (free_handle_block() != NULL) {
1983 JNIHandleBlock* block = free_handle_block();
1984 set_free_handle_block(NULL);
1985 JNIHandleBlock::release_block(block);
1986 }
1988 // These have to be removed while this is still a valid thread.
1989 remove_stack_guard_pages();
1991 if (UseTLAB) {
1992 tlab().make_parsable(true); // retire TLAB, if any
1993 }
1995 #if INCLUDE_ALL_GCS
1996 if (UseG1GC) {
1997 flush_barrier_queues();
1998 }
1999 #endif // INCLUDE_ALL_GCS
2001 Threads::remove(this);
2002 delete this;
2003 }
2008 JavaThread* JavaThread::active() {
2009 Thread* thread = ThreadLocalStorage::thread();
2010 assert(thread != NULL, "just checking");
2011 if (thread->is_Java_thread()) {
2012 return (JavaThread*) thread;
2013 } else {
2014 assert(thread->is_VM_thread(), "this must be a vm thread");
2015 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2016 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2017 assert(ret->is_Java_thread(), "must be a Java thread");
2018 return ret;
2019 }
2020 }
2022 bool JavaThread::is_lock_owned(address adr) const {
2023 if (Thread::is_lock_owned(adr)) return true;
2025 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2026 if (chunk->contains(adr)) return true;
2027 }
2029 return false;
2030 }
2033 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2034 chunk->set_next(monitor_chunks());
2035 set_monitor_chunks(chunk);
2036 }
2038 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2039 guarantee(monitor_chunks() != NULL, "must be non empty");
2040 if (monitor_chunks() == chunk) {
2041 set_monitor_chunks(chunk->next());
2042 } else {
2043 MonitorChunk* prev = monitor_chunks();
2044 while (prev->next() != chunk) prev = prev->next();
2045 prev->set_next(chunk->next());
2046 }
2047 }
2049 // JVM support.
2051 // Note: this function shouldn't block if it's called in
2052 // _thread_in_native_trans state (such as from
2053 // check_special_condition_for_native_trans()).
2054 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2056 if (has_last_Java_frame() && has_async_condition()) {
2057 // If we are at a polling page safepoint (not a poll return)
2058 // then we must defer async exception because live registers
2059 // will be clobbered by the exception path. Poll return is
2060 // ok because the call we a returning from already collides
2061 // with exception handling registers and so there is no issue.
2062 // (The exception handling path kills call result registers but
2063 // this is ok since the exception kills the result anyway).
2065 if (is_at_poll_safepoint()) {
2066 // if the code we are returning to has deoptimized we must defer
2067 // the exception otherwise live registers get clobbered on the
2068 // exception path before deoptimization is able to retrieve them.
2069 //
2070 RegisterMap map(this, false);
2071 frame caller_fr = last_frame().sender(&map);
2072 assert(caller_fr.is_compiled_frame(), "what?");
2073 if (caller_fr.is_deoptimized_frame()) {
2074 if (TraceExceptions) {
2075 ResourceMark rm;
2076 tty->print_cr("deferred async exception at compiled safepoint");
2077 }
2078 return;
2079 }
2080 }
2081 }
2083 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2084 if (condition == _no_async_condition) {
2085 // Conditions have changed since has_special_runtime_exit_condition()
2086 // was called:
2087 // - if we were here only because of an external suspend request,
2088 // then that was taken care of above (or cancelled) so we are done
2089 // - if we were here because of another async request, then it has
2090 // been cleared between the has_special_runtime_exit_condition()
2091 // and now so again we are done
2092 return;
2093 }
2095 // Check for pending async. exception
2096 if (_pending_async_exception != NULL) {
2097 // Only overwrite an already pending exception, if it is not a threadDeath.
2098 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2100 // We cannot call Exceptions::_throw(...) here because we cannot block
2101 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2103 if (TraceExceptions) {
2104 ResourceMark rm;
2105 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2106 if (has_last_Java_frame() ) {
2107 frame f = last_frame();
2108 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2109 }
2110 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2111 }
2112 _pending_async_exception = NULL;
2113 clear_has_async_exception();
2114 }
2115 }
2117 if (check_unsafe_error &&
2118 condition == _async_unsafe_access_error && !has_pending_exception()) {
2119 condition = _no_async_condition; // done
2120 switch (thread_state()) {
2121 case _thread_in_vm:
2122 {
2123 JavaThread* THREAD = this;
2124 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2125 }
2126 case _thread_in_native:
2127 {
2128 ThreadInVMfromNative tiv(this);
2129 JavaThread* THREAD = this;
2130 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2131 }
2132 case _thread_in_Java:
2133 {
2134 ThreadInVMfromJava tiv(this);
2135 JavaThread* THREAD = this;
2136 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2137 }
2138 default:
2139 ShouldNotReachHere();
2140 }
2141 }
2143 assert(condition == _no_async_condition || has_pending_exception() ||
2144 (!check_unsafe_error && condition == _async_unsafe_access_error),
2145 "must have handled the async condition, if no exception");
2146 }
2148 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2149 //
2150 // Check for pending external suspend. Internal suspend requests do
2151 // not use handle_special_runtime_exit_condition().
2152 // If JNIEnv proxies are allowed, don't self-suspend if the target
2153 // thread is not the current thread. In older versions of jdbx, jdbx
2154 // threads could call into the VM with another thread's JNIEnv so we
2155 // can be here operating on behalf of a suspended thread (4432884).
2156 bool do_self_suspend = is_external_suspend_with_lock();
2157 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2158 //
2159 // Because thread is external suspended the safepoint code will count
2160 // thread as at a safepoint. This can be odd because we can be here
2161 // as _thread_in_Java which would normally transition to _thread_blocked
2162 // at a safepoint. We would like to mark the thread as _thread_blocked
2163 // before calling java_suspend_self like all other callers of it but
2164 // we must then observe proper safepoint protocol. (We can't leave
2165 // _thread_blocked with a safepoint in progress). However we can be
2166 // here as _thread_in_native_trans so we can't use a normal transition
2167 // constructor/destructor pair because they assert on that type of
2168 // transition. We could do something like:
2169 //
2170 // JavaThreadState state = thread_state();
2171 // set_thread_state(_thread_in_vm);
2172 // {
2173 // ThreadBlockInVM tbivm(this);
2174 // java_suspend_self()
2175 // }
2176 // set_thread_state(_thread_in_vm_trans);
2177 // if (safepoint) block;
2178 // set_thread_state(state);
2179 //
2180 // but that is pretty messy. Instead we just go with the way the
2181 // code has worked before and note that this is the only path to
2182 // java_suspend_self that doesn't put the thread in _thread_blocked
2183 // mode.
2185 frame_anchor()->make_walkable(this);
2186 java_suspend_self();
2188 // We might be here for reasons in addition to the self-suspend request
2189 // so check for other async requests.
2190 }
2192 if (check_asyncs) {
2193 check_and_handle_async_exceptions();
2194 }
2195 }
2197 void JavaThread::send_thread_stop(oop java_throwable) {
2198 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2199 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2200 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2202 // Do not throw asynchronous exceptions against the compiler thread
2203 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2204 if (is_Compiler_thread()) return;
2206 {
2207 // Actually throw the Throwable against the target Thread - however
2208 // only if there is no thread death exception installed already.
2209 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2210 // If the topmost frame is a runtime stub, then we are calling into
2211 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2212 // must deoptimize the caller before continuing, as the compiled exception handler table
2213 // may not be valid
2214 if (has_last_Java_frame()) {
2215 frame f = last_frame();
2216 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2217 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2218 RegisterMap reg_map(this, UseBiasedLocking);
2219 frame compiled_frame = f.sender(®_map);
2220 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2221 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2222 }
2223 }
2224 }
2226 // Set async. pending exception in thread.
2227 set_pending_async_exception(java_throwable);
2229 if (TraceExceptions) {
2230 ResourceMark rm;
2231 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2232 }
2233 // for AbortVMOnException flag
2234 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2235 }
2236 }
2239 // Interrupt thread so it will wake up from a potential wait()
2240 Thread::interrupt(this);
2241 }
2243 // External suspension mechanism.
2244 //
2245 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2246 // to any VM_locks and it is at a transition
2247 // Self-suspension will happen on the transition out of the vm.
2248 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2249 //
2250 // Guarantees on return:
2251 // + Target thread will not execute any new bytecode (that's why we need to
2252 // force a safepoint)
2253 // + Target thread will not enter any new monitors
2254 //
2255 void JavaThread::java_suspend() {
2256 { MutexLocker mu(Threads_lock);
2257 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2258 return;
2259 }
2260 }
2262 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2263 if (!is_external_suspend()) {
2264 // a racing resume has cancelled us; bail out now
2265 return;
2266 }
2268 // suspend is done
2269 uint32_t debug_bits = 0;
2270 // Warning: is_ext_suspend_completed() may temporarily drop the
2271 // SR_lock to allow the thread to reach a stable thread state if
2272 // it is currently in a transient thread state.
2273 if (is_ext_suspend_completed(false /* !called_by_wait */,
2274 SuspendRetryDelay, &debug_bits) ) {
2275 return;
2276 }
2277 }
2279 VM_ForceSafepoint vm_suspend;
2280 VMThread::execute(&vm_suspend);
2281 }
2283 // Part II of external suspension.
2284 // A JavaThread self suspends when it detects a pending external suspend
2285 // request. This is usually on transitions. It is also done in places
2286 // where continuing to the next transition would surprise the caller,
2287 // e.g., monitor entry.
2288 //
2289 // Returns the number of times that the thread self-suspended.
2290 //
2291 // Note: DO NOT call java_suspend_self() when you just want to block current
2292 // thread. java_suspend_self() is the second stage of cooperative
2293 // suspension for external suspend requests and should only be used
2294 // to complete an external suspend request.
2295 //
2296 int JavaThread::java_suspend_self() {
2297 int ret = 0;
2299 // we are in the process of exiting so don't suspend
2300 if (is_exiting()) {
2301 clear_external_suspend();
2302 return ret;
2303 }
2305 assert(_anchor.walkable() ||
2306 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2307 "must have walkable stack");
2309 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2311 assert(!this->is_ext_suspended(),
2312 "a thread trying to self-suspend should not already be suspended");
2314 if (this->is_suspend_equivalent()) {
2315 // If we are self-suspending as a result of the lifting of a
2316 // suspend equivalent condition, then the suspend_equivalent
2317 // flag is not cleared until we set the ext_suspended flag so
2318 // that wait_for_ext_suspend_completion() returns consistent
2319 // results.
2320 this->clear_suspend_equivalent();
2321 }
2323 // A racing resume may have cancelled us before we grabbed SR_lock
2324 // above. Or another external suspend request could be waiting for us
2325 // by the time we return from SR_lock()->wait(). The thread
2326 // that requested the suspension may already be trying to walk our
2327 // stack and if we return now, we can change the stack out from under
2328 // it. This would be a "bad thing (TM)" and cause the stack walker
2329 // to crash. We stay self-suspended until there are no more pending
2330 // external suspend requests.
2331 while (is_external_suspend()) {
2332 ret++;
2333 this->set_ext_suspended();
2335 // _ext_suspended flag is cleared by java_resume()
2336 while (is_ext_suspended()) {
2337 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2338 }
2339 }
2341 return ret;
2342 }
2344 #ifdef ASSERT
2345 // verify the JavaThread has not yet been published in the Threads::list, and
2346 // hence doesn't need protection from concurrent access at this stage
2347 void JavaThread::verify_not_published() {
2348 if (!Threads_lock->owned_by_self()) {
2349 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2350 assert( !Threads::includes(this),
2351 "java thread shouldn't have been published yet!");
2352 }
2353 else {
2354 assert( !Threads::includes(this),
2355 "java thread shouldn't have been published yet!");
2356 }
2357 }
2358 #endif
2360 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2361 // progress or when _suspend_flags is non-zero.
2362 // Current thread needs to self-suspend if there is a suspend request and/or
2363 // block if a safepoint is in progress.
2364 // Async exception ISN'T checked.
2365 // Note only the ThreadInVMfromNative transition can call this function
2366 // directly and when thread state is _thread_in_native_trans
2367 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2368 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2370 JavaThread *curJT = JavaThread::current();
2371 bool do_self_suspend = thread->is_external_suspend();
2373 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2375 // If JNIEnv proxies are allowed, don't self-suspend if the target
2376 // thread is not the current thread. In older versions of jdbx, jdbx
2377 // threads could call into the VM with another thread's JNIEnv so we
2378 // can be here operating on behalf of a suspended thread (4432884).
2379 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2380 JavaThreadState state = thread->thread_state();
2382 // We mark this thread_blocked state as a suspend-equivalent so
2383 // that a caller to is_ext_suspend_completed() won't be confused.
2384 // The suspend-equivalent state is cleared by java_suspend_self().
2385 thread->set_suspend_equivalent();
2387 // If the safepoint code sees the _thread_in_native_trans state, it will
2388 // wait until the thread changes to other thread state. There is no
2389 // guarantee on how soon we can obtain the SR_lock and complete the
2390 // self-suspend request. It would be a bad idea to let safepoint wait for
2391 // too long. Temporarily change the state to _thread_blocked to
2392 // let the VM thread know that this thread is ready for GC. The problem
2393 // of changing thread state is that safepoint could happen just after
2394 // java_suspend_self() returns after being resumed, and VM thread will
2395 // see the _thread_blocked state. We must check for safepoint
2396 // after restoring the state and make sure we won't leave while a safepoint
2397 // is in progress.
2398 thread->set_thread_state(_thread_blocked);
2399 thread->java_suspend_self();
2400 thread->set_thread_state(state);
2401 // Make sure new state is seen by VM thread
2402 if (os::is_MP()) {
2403 if (UseMembar) {
2404 // Force a fence between the write above and read below
2405 OrderAccess::fence();
2406 } else {
2407 // Must use this rather than serialization page in particular on Windows
2408 InterfaceSupport::serialize_memory(thread);
2409 }
2410 }
2411 }
2413 if (SafepointSynchronize::do_call_back()) {
2414 // If we are safepointing, then block the caller which may not be
2415 // the same as the target thread (see above).
2416 SafepointSynchronize::block(curJT);
2417 }
2419 if (thread->is_deopt_suspend()) {
2420 thread->clear_deopt_suspend();
2421 RegisterMap map(thread, false);
2422 frame f = thread->last_frame();
2423 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2424 f = f.sender(&map);
2425 }
2426 if (f.id() == thread->must_deopt_id()) {
2427 thread->clear_must_deopt_id();
2428 f.deoptimize(thread);
2429 } else {
2430 fatal("missed deoptimization!");
2431 }
2432 }
2433 }
2435 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2436 // progress or when _suspend_flags is non-zero.
2437 // Current thread needs to self-suspend if there is a suspend request and/or
2438 // block if a safepoint is in progress.
2439 // Also check for pending async exception (not including unsafe access error).
2440 // Note only the native==>VM/Java barriers can call this function and when
2441 // thread state is _thread_in_native_trans.
2442 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2443 check_safepoint_and_suspend_for_native_trans(thread);
2445 if (thread->has_async_exception()) {
2446 // We are in _thread_in_native_trans state, don't handle unsafe
2447 // access error since that may block.
2448 thread->check_and_handle_async_exceptions(false);
2449 }
2450 }
2452 // This is a variant of the normal
2453 // check_special_condition_for_native_trans with slightly different
2454 // semantics for use by critical native wrappers. It does all the
2455 // normal checks but also performs the transition back into
2456 // thread_in_Java state. This is required so that critical natives
2457 // can potentially block and perform a GC if they are the last thread
2458 // exiting the GC_locker.
2459 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2460 check_special_condition_for_native_trans(thread);
2462 // Finish the transition
2463 thread->set_thread_state(_thread_in_Java);
2465 if (thread->do_critical_native_unlock()) {
2466 ThreadInVMfromJavaNoAsyncException tiv(thread);
2467 GC_locker::unlock_critical(thread);
2468 thread->clear_critical_native_unlock();
2469 }
2470 }
2472 // We need to guarantee the Threads_lock here, since resumes are not
2473 // allowed during safepoint synchronization
2474 // Can only resume from an external suspension
2475 void JavaThread::java_resume() {
2476 assert_locked_or_safepoint(Threads_lock);
2478 // Sanity check: thread is gone, has started exiting or the thread
2479 // was not externally suspended.
2480 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2481 return;
2482 }
2484 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2486 clear_external_suspend();
2488 if (is_ext_suspended()) {
2489 clear_ext_suspended();
2490 SR_lock()->notify_all();
2491 }
2492 }
2494 void JavaThread::create_stack_guard_pages() {
2495 if (!os::uses_stack_guard_pages() ||
2496 _stack_guard_state != stack_guard_unused ||
2497 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2498 if (TraceThreadEvents) {
2499 tty->print_cr("Stack guard page creation for thread "
2500 UINTX_FORMAT " disabled", os::current_thread_id());
2501 }
2502 return;
2503 }
2504 address low_addr = stack_base() - stack_size();
2505 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2507 int allocate = os::allocate_stack_guard_pages();
2508 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2510 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2511 warning("Attempt to allocate stack guard pages failed.");
2512 return;
2513 }
2515 if (os::guard_memory((char *) low_addr, len)) {
2516 _stack_guard_state = stack_guard_enabled;
2517 } else {
2518 warning("Attempt to protect stack guard pages failed.");
2519 if (os::uncommit_memory((char *) low_addr, len)) {
2520 warning("Attempt to deallocate stack guard pages failed.");
2521 }
2522 }
2523 }
2525 void JavaThread::remove_stack_guard_pages() {
2526 assert(Thread::current() == this, "from different thread");
2527 if (_stack_guard_state == stack_guard_unused) return;
2528 address low_addr = stack_base() - stack_size();
2529 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2531 if (os::allocate_stack_guard_pages()) {
2532 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2533 _stack_guard_state = stack_guard_unused;
2534 } else {
2535 warning("Attempt to deallocate stack guard pages failed.");
2536 }
2537 } else {
2538 if (_stack_guard_state == stack_guard_unused) return;
2539 if (os::unguard_memory((char *) low_addr, len)) {
2540 _stack_guard_state = stack_guard_unused;
2541 } else {
2542 warning("Attempt to unprotect stack guard pages failed.");
2543 }
2544 }
2545 }
2547 void JavaThread::enable_stack_yellow_zone() {
2548 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2549 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2551 // The base notation is from the stacks point of view, growing downward.
2552 // We need to adjust it to work correctly with guard_memory()
2553 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2555 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2556 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2558 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2559 _stack_guard_state = stack_guard_enabled;
2560 } else {
2561 warning("Attempt to guard stack yellow zone failed.");
2562 }
2563 enable_register_stack_guard();
2564 }
2566 void JavaThread::disable_stack_yellow_zone() {
2567 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2568 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2570 // Simply return if called for a thread that does not use guard pages.
2571 if (_stack_guard_state == stack_guard_unused) return;
2573 // The base notation is from the stacks point of view, growing downward.
2574 // We need to adjust it to work correctly with guard_memory()
2575 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2577 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2578 _stack_guard_state = stack_guard_yellow_disabled;
2579 } else {
2580 warning("Attempt to unguard stack yellow zone failed.");
2581 }
2582 disable_register_stack_guard();
2583 }
2585 void JavaThread::enable_stack_red_zone() {
2586 // The base notation is from the stacks point of view, growing downward.
2587 // We need to adjust it to work correctly with guard_memory()
2588 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2589 address base = stack_red_zone_base() - stack_red_zone_size();
2591 guarantee(base < stack_base(),"Error calculating stack red zone");
2592 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2594 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2595 warning("Attempt to guard stack red zone failed.");
2596 }
2597 }
2599 void JavaThread::disable_stack_red_zone() {
2600 // The base notation is from the stacks point of view, growing downward.
2601 // We need to adjust it to work correctly with guard_memory()
2602 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2603 address base = stack_red_zone_base() - stack_red_zone_size();
2604 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2605 warning("Attempt to unguard stack red zone failed.");
2606 }
2607 }
2609 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2610 // ignore is there is no stack
2611 if (!has_last_Java_frame()) return;
2612 // traverse the stack frames. Starts from top frame.
2613 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2614 frame* fr = fst.current();
2615 f(fr, fst.register_map());
2616 }
2617 }
2620 #ifndef PRODUCT
2621 // Deoptimization
2622 // Function for testing deoptimization
2623 void JavaThread::deoptimize() {
2624 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2625 StackFrameStream fst(this, UseBiasedLocking);
2626 bool deopt = false; // Dump stack only if a deopt actually happens.
2627 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2628 // Iterate over all frames in the thread and deoptimize
2629 for(; !fst.is_done(); fst.next()) {
2630 if(fst.current()->can_be_deoptimized()) {
2632 if (only_at) {
2633 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2634 // consists of comma or carriage return separated numbers so
2635 // search for the current bci in that string.
2636 address pc = fst.current()->pc();
2637 nmethod* nm = (nmethod*) fst.current()->cb();
2638 ScopeDesc* sd = nm->scope_desc_at( pc);
2639 char buffer[8];
2640 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2641 size_t len = strlen(buffer);
2642 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2643 while (found != NULL) {
2644 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2645 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2646 // Check that the bci found is bracketed by terminators.
2647 break;
2648 }
2649 found = strstr(found + 1, buffer);
2650 }
2651 if (!found) {
2652 continue;
2653 }
2654 }
2656 if (DebugDeoptimization && !deopt) {
2657 deopt = true; // One-time only print before deopt
2658 tty->print_cr("[BEFORE Deoptimization]");
2659 trace_frames();
2660 trace_stack();
2661 }
2662 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2663 }
2664 }
2666 if (DebugDeoptimization && deopt) {
2667 tty->print_cr("[AFTER Deoptimization]");
2668 trace_frames();
2669 }
2670 }
2673 // Make zombies
2674 void JavaThread::make_zombies() {
2675 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2676 if (fst.current()->can_be_deoptimized()) {
2677 // it is a Java nmethod
2678 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2679 nm->make_not_entrant();
2680 }
2681 }
2682 }
2683 #endif // PRODUCT
2686 void JavaThread::deoptimized_wrt_marked_nmethods() {
2687 if (!has_last_Java_frame()) return;
2688 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2689 StackFrameStream fst(this, UseBiasedLocking);
2690 for(; !fst.is_done(); fst.next()) {
2691 if (fst.current()->should_be_deoptimized()) {
2692 if (LogCompilation && xtty != NULL) {
2693 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2694 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2695 this->name(), nm != NULL ? nm->compile_id() : -1);
2696 }
2698 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2699 }
2700 }
2701 }
2704 // GC support
2705 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2707 void JavaThread::gc_epilogue() {
2708 frames_do(frame_gc_epilogue);
2709 }
2712 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2714 void JavaThread::gc_prologue() {
2715 frames_do(frame_gc_prologue);
2716 }
2718 // If the caller is a NamedThread, then remember, in the current scope,
2719 // the given JavaThread in its _processed_thread field.
2720 class RememberProcessedThread: public StackObj {
2721 NamedThread* _cur_thr;
2722 public:
2723 RememberProcessedThread(JavaThread* jthr) {
2724 Thread* thread = Thread::current();
2725 if (thread->is_Named_thread()) {
2726 _cur_thr = (NamedThread *)thread;
2727 _cur_thr->set_processed_thread(jthr);
2728 } else {
2729 _cur_thr = NULL;
2730 }
2731 }
2733 ~RememberProcessedThread() {
2734 if (_cur_thr) {
2735 _cur_thr->set_processed_thread(NULL);
2736 }
2737 }
2738 };
2740 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2741 // Verify that the deferred card marks have been flushed.
2742 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2744 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2745 // since there may be more than one thread using each ThreadProfiler.
2747 // Traverse the GCHandles
2748 Thread::oops_do(f, cld_f, cf);
2750 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2751 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2753 if (has_last_Java_frame()) {
2754 // Record JavaThread to GC thread
2755 RememberProcessedThread rpt(this);
2757 // Traverse the privileged stack
2758 if (_privileged_stack_top != NULL) {
2759 _privileged_stack_top->oops_do(f);
2760 }
2762 // traverse the registered growable array
2763 if (_array_for_gc != NULL) {
2764 for (int index = 0; index < _array_for_gc->length(); index++) {
2765 f->do_oop(_array_for_gc->adr_at(index));
2766 }
2767 }
2769 // Traverse the monitor chunks
2770 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2771 chunk->oops_do(f);
2772 }
2774 // Traverse the execution stack
2775 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2776 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2777 }
2778 }
2780 // callee_target is never live across a gc point so NULL it here should
2781 // it still contain a methdOop.
2783 set_callee_target(NULL);
2785 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2786 // If we have deferred set_locals there might be oops waiting to be
2787 // written
2788 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2789 if (list != NULL) {
2790 for (int i = 0; i < list->length(); i++) {
2791 list->at(i)->oops_do(f);
2792 }
2793 }
2795 // Traverse instance variables at the end since the GC may be moving things
2796 // around using this function
2797 f->do_oop((oop*) &_threadObj);
2798 f->do_oop((oop*) &_vm_result);
2799 f->do_oop((oop*) &_exception_oop);
2800 f->do_oop((oop*) &_pending_async_exception);
2802 if (jvmti_thread_state() != NULL) {
2803 jvmti_thread_state()->oops_do(f);
2804 }
2805 }
2807 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2808 Thread::nmethods_do(cf); // (super method is a no-op)
2810 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2811 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2813 if (has_last_Java_frame()) {
2814 // Traverse the execution stack
2815 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2816 fst.current()->nmethods_do(cf);
2817 }
2818 }
2819 }
2821 void JavaThread::metadata_do(void f(Metadata*)) {
2822 Thread::metadata_do(f);
2823 if (has_last_Java_frame()) {
2824 // Traverse the execution stack to call f() on the methods in the stack
2825 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2826 fst.current()->metadata_do(f);
2827 }
2828 } else if (is_Compiler_thread()) {
2829 // need to walk ciMetadata in current compile tasks to keep alive.
2830 CompilerThread* ct = (CompilerThread*)this;
2831 if (ct->env() != NULL) {
2832 ct->env()->metadata_do(f);
2833 }
2834 }
2835 }
2837 // Printing
2838 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2839 switch (_thread_state) {
2840 case _thread_uninitialized: return "_thread_uninitialized";
2841 case _thread_new: return "_thread_new";
2842 case _thread_new_trans: return "_thread_new_trans";
2843 case _thread_in_native: return "_thread_in_native";
2844 case _thread_in_native_trans: return "_thread_in_native_trans";
2845 case _thread_in_vm: return "_thread_in_vm";
2846 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2847 case _thread_in_Java: return "_thread_in_Java";
2848 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2849 case _thread_blocked: return "_thread_blocked";
2850 case _thread_blocked_trans: return "_thread_blocked_trans";
2851 default: return "unknown thread state";
2852 }
2853 }
2855 #ifndef PRODUCT
2856 void JavaThread::print_thread_state_on(outputStream *st) const {
2857 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2858 };
2859 void JavaThread::print_thread_state() const {
2860 print_thread_state_on(tty);
2861 };
2862 #endif // PRODUCT
2864 // Called by Threads::print() for VM_PrintThreads operation
2865 void JavaThread::print_on(outputStream *st) const {
2866 st->print("\"%s\" ", get_thread_name());
2867 oop thread_oop = threadObj();
2868 if (thread_oop != NULL) {
2869 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2870 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2871 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2872 }
2873 Thread::print_on(st);
2874 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2875 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2876 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2877 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2878 }
2879 #ifndef PRODUCT
2880 print_thread_state_on(st);
2881 _safepoint_state->print_on(st);
2882 #endif // PRODUCT
2883 }
2885 // Called by fatal error handler. The difference between this and
2886 // JavaThread::print() is that we can't grab lock or allocate memory.
2887 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2888 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2889 oop thread_obj = threadObj();
2890 if (thread_obj != NULL) {
2891 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2892 }
2893 st->print(" [");
2894 st->print("%s", _get_thread_state_name(_thread_state));
2895 if (osthread()) {
2896 st->print(", id=%d", osthread()->thread_id());
2897 }
2898 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2899 _stack_base - _stack_size, _stack_base);
2900 st->print("]");
2901 return;
2902 }
2904 // Verification
2906 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2908 void JavaThread::verify() {
2909 // Verify oops in the thread.
2910 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2912 // Verify the stack frames.
2913 frames_do(frame_verify);
2914 }
2916 // CR 6300358 (sub-CR 2137150)
2917 // Most callers of this method assume that it can't return NULL but a
2918 // thread may not have a name whilst it is in the process of attaching to
2919 // the VM - see CR 6412693, and there are places where a JavaThread can be
2920 // seen prior to having it's threadObj set (eg JNI attaching threads and
2921 // if vm exit occurs during initialization). These cases can all be accounted
2922 // for such that this method never returns NULL.
2923 const char* JavaThread::get_thread_name() const {
2924 #ifdef ASSERT
2925 // early safepoints can hit while current thread does not yet have TLS
2926 if (!SafepointSynchronize::is_at_safepoint()) {
2927 Thread *cur = Thread::current();
2928 if (!(cur->is_Java_thread() && cur == this)) {
2929 // Current JavaThreads are allowed to get their own name without
2930 // the Threads_lock.
2931 assert_locked_or_safepoint(Threads_lock);
2932 }
2933 }
2934 #endif // ASSERT
2935 return get_thread_name_string();
2936 }
2938 // Returns a non-NULL representation of this thread's name, or a suitable
2939 // descriptive string if there is no set name
2940 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2941 const char* name_str;
2942 oop thread_obj = threadObj();
2943 if (thread_obj != NULL) {
2944 oop name = java_lang_Thread::name(thread_obj);
2945 if (name != NULL) {
2946 if (buf == NULL) {
2947 name_str = java_lang_String::as_utf8_string(name);
2948 }
2949 else {
2950 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2951 }
2952 }
2953 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2954 name_str = "<no-name - thread is attaching>";
2955 }
2956 else {
2957 name_str = Thread::name();
2958 }
2959 }
2960 else {
2961 name_str = Thread::name();
2962 }
2963 assert(name_str != NULL, "unexpected NULL thread name");
2964 return name_str;
2965 }
2968 const char* JavaThread::get_threadgroup_name() const {
2969 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2970 oop thread_obj = threadObj();
2971 if (thread_obj != NULL) {
2972 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2973 if (thread_group != NULL) {
2974 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2975 // ThreadGroup.name can be null
2976 if (name != NULL) {
2977 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2978 return str;
2979 }
2980 }
2981 }
2982 return NULL;
2983 }
2985 const char* JavaThread::get_parent_name() const {
2986 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2987 oop thread_obj = threadObj();
2988 if (thread_obj != NULL) {
2989 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2990 if (thread_group != NULL) {
2991 oop parent = java_lang_ThreadGroup::parent(thread_group);
2992 if (parent != NULL) {
2993 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2994 // ThreadGroup.name can be null
2995 if (name != NULL) {
2996 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2997 return str;
2998 }
2999 }
3000 }
3001 }
3002 return NULL;
3003 }
3005 ThreadPriority JavaThread::java_priority() const {
3006 oop thr_oop = threadObj();
3007 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3008 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3009 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3010 return priority;
3011 }
3013 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3015 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3016 // Link Java Thread object <-> C++ Thread
3018 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3019 // and put it into a new Handle. The Handle "thread_oop" can then
3020 // be used to pass the C++ thread object to other methods.
3022 // Set the Java level thread object (jthread) field of the
3023 // new thread (a JavaThread *) to C++ thread object using the
3024 // "thread_oop" handle.
3026 // Set the thread field (a JavaThread *) of the
3027 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3029 Handle thread_oop(Thread::current(),
3030 JNIHandles::resolve_non_null(jni_thread));
3031 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3032 "must be initialized");
3033 set_threadObj(thread_oop());
3034 java_lang_Thread::set_thread(thread_oop(), this);
3036 if (prio == NoPriority) {
3037 prio = java_lang_Thread::priority(thread_oop());
3038 assert(prio != NoPriority, "A valid priority should be present");
3039 }
3041 // Push the Java priority down to the native thread; needs Threads_lock
3042 Thread::set_priority(this, prio);
3044 prepare_ext();
3046 // Add the new thread to the Threads list and set it in motion.
3047 // We must have threads lock in order to call Threads::add.
3048 // It is crucial that we do not block before the thread is
3049 // added to the Threads list for if a GC happens, then the java_thread oop
3050 // will not be visited by GC.
3051 Threads::add(this);
3052 }
3054 oop JavaThread::current_park_blocker() {
3055 // Support for JSR-166 locks
3056 oop thread_oop = threadObj();
3057 if (thread_oop != NULL &&
3058 JDK_Version::current().supports_thread_park_blocker()) {
3059 return java_lang_Thread::park_blocker(thread_oop);
3060 }
3061 return NULL;
3062 }
3065 void JavaThread::print_stack_on(outputStream* st) {
3066 if (!has_last_Java_frame()) return;
3067 ResourceMark rm;
3068 HandleMark hm;
3070 RegisterMap reg_map(this);
3071 vframe* start_vf = last_java_vframe(®_map);
3072 int count = 0;
3073 for (vframe* f = start_vf; f; f = f->sender() ) {
3074 if (f->is_java_frame()) {
3075 javaVFrame* jvf = javaVFrame::cast(f);
3076 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3078 // Print out lock information
3079 if (JavaMonitorsInStackTrace) {
3080 jvf->print_lock_info_on(st, count);
3081 }
3082 } else {
3083 // Ignore non-Java frames
3084 }
3086 // Bail-out case for too deep stacks
3087 count++;
3088 if (MaxJavaStackTraceDepth == count) return;
3089 }
3090 }
3093 // JVMTI PopFrame support
3094 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3095 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3096 if (in_bytes(size_in_bytes) != 0) {
3097 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3098 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3099 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3100 }
3101 }
3103 void* JavaThread::popframe_preserved_args() {
3104 return _popframe_preserved_args;
3105 }
3107 ByteSize JavaThread::popframe_preserved_args_size() {
3108 return in_ByteSize(_popframe_preserved_args_size);
3109 }
3111 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3112 int sz = in_bytes(popframe_preserved_args_size());
3113 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3114 return in_WordSize(sz / wordSize);
3115 }
3117 void JavaThread::popframe_free_preserved_args() {
3118 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3119 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3120 _popframe_preserved_args = NULL;
3121 _popframe_preserved_args_size = 0;
3122 }
3124 #ifndef PRODUCT
3126 void JavaThread::trace_frames() {
3127 tty->print_cr("[Describe stack]");
3128 int frame_no = 1;
3129 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3130 tty->print(" %d. ", frame_no++);
3131 fst.current()->print_value_on(tty,this);
3132 tty->cr();
3133 }
3134 }
3136 class PrintAndVerifyOopClosure: public OopClosure {
3137 protected:
3138 template <class T> inline void do_oop_work(T* p) {
3139 oop obj = oopDesc::load_decode_heap_oop(p);
3140 if (obj == NULL) return;
3141 tty->print(INTPTR_FORMAT ": ", p);
3142 if (obj->is_oop_or_null()) {
3143 if (obj->is_objArray()) {
3144 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3145 } else {
3146 obj->print();
3147 }
3148 } else {
3149 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3150 }
3151 tty->cr();
3152 }
3153 public:
3154 virtual void do_oop(oop* p) { do_oop_work(p); }
3155 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3156 };
3159 static void oops_print(frame* f, const RegisterMap *map) {
3160 PrintAndVerifyOopClosure print;
3161 f->print_value();
3162 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3163 }
3165 // Print our all the locations that contain oops and whether they are
3166 // valid or not. This useful when trying to find the oldest frame
3167 // where an oop has gone bad since the frame walk is from youngest to
3168 // oldest.
3169 void JavaThread::trace_oops() {
3170 tty->print_cr("[Trace oops]");
3171 frames_do(oops_print);
3172 }
3175 #ifdef ASSERT
3176 // Print or validate the layout of stack frames
3177 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3178 ResourceMark rm;
3179 PRESERVE_EXCEPTION_MARK;
3180 FrameValues values;
3181 int frame_no = 0;
3182 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3183 fst.current()->describe(values, ++frame_no);
3184 if (depth == frame_no) break;
3185 }
3186 if (validate_only) {
3187 values.validate();
3188 } else {
3189 tty->print_cr("[Describe stack layout]");
3190 values.print(this);
3191 }
3192 }
3193 #endif
3195 void JavaThread::trace_stack_from(vframe* start_vf) {
3196 ResourceMark rm;
3197 int vframe_no = 1;
3198 for (vframe* f = start_vf; f; f = f->sender() ) {
3199 if (f->is_java_frame()) {
3200 javaVFrame::cast(f)->print_activation(vframe_no++);
3201 } else {
3202 f->print();
3203 }
3204 if (vframe_no > StackPrintLimit) {
3205 tty->print_cr("...<more frames>...");
3206 return;
3207 }
3208 }
3209 }
3212 void JavaThread::trace_stack() {
3213 if (!has_last_Java_frame()) return;
3214 ResourceMark rm;
3215 HandleMark hm;
3216 RegisterMap reg_map(this);
3217 trace_stack_from(last_java_vframe(®_map));
3218 }
3221 #endif // PRODUCT
3224 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3225 assert(reg_map != NULL, "a map must be given");
3226 frame f = last_frame();
3227 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3228 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3229 }
3230 return NULL;
3231 }
3234 Klass* JavaThread::security_get_caller_class(int depth) {
3235 vframeStream vfst(this);
3236 vfst.security_get_caller_frame(depth);
3237 if (!vfst.at_end()) {
3238 return vfst.method()->method_holder();
3239 }
3240 return NULL;
3241 }
3243 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3244 assert(thread->is_Compiler_thread(), "must be compiler thread");
3245 CompileBroker::compiler_thread_loop();
3246 }
3248 // Create a CompilerThread
3249 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3250 : JavaThread(&compiler_thread_entry) {
3251 _env = NULL;
3252 _log = NULL;
3253 _task = NULL;
3254 _queue = queue;
3255 _counters = counters;
3256 _buffer_blob = NULL;
3257 _scanned_nmethod = NULL;
3258 _compiler = NULL;
3260 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3261 resource_area()->bias_to(mtCompiler);
3263 #ifndef PRODUCT
3264 _ideal_graph_printer = NULL;
3265 #endif
3266 }
3268 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3269 JavaThread::oops_do(f, cld_f, cf);
3270 if (_scanned_nmethod != NULL && cf != NULL) {
3271 // Safepoints can occur when the sweeper is scanning an nmethod so
3272 // process it here to make sure it isn't unloaded in the middle of
3273 // a scan.
3274 cf->do_code_blob(_scanned_nmethod);
3275 }
3276 }
3279 // ======= Threads ========
3281 // The Threads class links together all active threads, and provides
3282 // operations over all threads. It is protected by its own Mutex
3283 // lock, which is also used in other contexts to protect thread
3284 // operations from having the thread being operated on from exiting
3285 // and going away unexpectedly (e.g., safepoint synchronization)
3287 JavaThread* Threads::_thread_list = NULL;
3288 int Threads::_number_of_threads = 0;
3289 int Threads::_number_of_non_daemon_threads = 0;
3290 int Threads::_return_code = 0;
3291 size_t JavaThread::_stack_size_at_create = 0;
3292 #ifdef ASSERT
3293 bool Threads::_vm_complete = false;
3294 #endif
3296 // All JavaThreads
3297 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3299 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3300 void Threads::threads_do(ThreadClosure* tc) {
3301 assert_locked_or_safepoint(Threads_lock);
3302 // ALL_JAVA_THREADS iterates through all JavaThreads
3303 ALL_JAVA_THREADS(p) {
3304 tc->do_thread(p);
3305 }
3306 // Someday we could have a table or list of all non-JavaThreads.
3307 // For now, just manually iterate through them.
3308 tc->do_thread(VMThread::vm_thread());
3309 Universe::heap()->gc_threads_do(tc);
3310 WatcherThread *wt = WatcherThread::watcher_thread();
3311 // Strictly speaking, the following NULL check isn't sufficient to make sure
3312 // the data for WatcherThread is still valid upon being examined. However,
3313 // considering that WatchThread terminates when the VM is on the way to
3314 // exit at safepoint, the chance of the above is extremely small. The right
3315 // way to prevent termination of WatcherThread would be to acquire
3316 // Terminator_lock, but we can't do that without violating the lock rank
3317 // checking in some cases.
3318 if (wt != NULL)
3319 tc->do_thread(wt);
3321 // If CompilerThreads ever become non-JavaThreads, add them here
3322 }
3324 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3326 extern void JDK_Version_init();
3328 // Preinitialize version info.
3329 VM_Version::early_initialize();
3331 // Check version
3332 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3334 // Initialize the output stream module
3335 ostream_init();
3337 // Process java launcher properties.
3338 Arguments::process_sun_java_launcher_properties(args);
3340 // Initialize the os module before using TLS
3341 os::init();
3343 // Initialize system properties.
3344 Arguments::init_system_properties();
3346 // So that JDK version can be used as a discrimintor when parsing arguments
3347 JDK_Version_init();
3349 // Update/Initialize System properties after JDK version number is known
3350 Arguments::init_version_specific_system_properties();
3352 // Parse arguments
3353 // Note: this internally calls os::init_container_support()
3354 jint parse_result = Arguments::parse(args);
3355 if (parse_result != JNI_OK) return parse_result;
3357 os::init_before_ergo();
3359 jint ergo_result = Arguments::apply_ergo();
3360 if (ergo_result != JNI_OK) return ergo_result;
3362 if (PauseAtStartup) {
3363 os::pause();
3364 }
3366 #ifndef USDT2
3367 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3368 #else /* USDT2 */
3369 HOTSPOT_VM_INIT_BEGIN();
3370 #endif /* USDT2 */
3372 // Record VM creation timing statistics
3373 TraceVmCreationTime create_vm_timer;
3374 create_vm_timer.start();
3376 // Timing (must come after argument parsing)
3377 TraceTime timer("Create VM", TraceStartupTime);
3379 // Initialize the os module after parsing the args
3380 jint os_init_2_result = os::init_2();
3381 if (os_init_2_result != JNI_OK) return os_init_2_result;
3383 jint adjust_after_os_result = Arguments::adjust_after_os();
3384 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3386 // intialize TLS
3387 ThreadLocalStorage::init();
3389 // Initialize output stream logging
3390 ostream_init_log();
3392 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3393 // Must be before create_vm_init_agents()
3394 if (Arguments::init_libraries_at_startup()) {
3395 convert_vm_init_libraries_to_agents();
3396 }
3398 // Launch -agentlib/-agentpath and converted -Xrun agents
3399 if (Arguments::init_agents_at_startup()) {
3400 create_vm_init_agents();
3401 }
3403 // Initialize Threads state
3404 _thread_list = NULL;
3405 _number_of_threads = 0;
3406 _number_of_non_daemon_threads = 0;
3408 // Initialize global data structures and create system classes in heap
3409 vm_init_globals();
3411 // Attach the main thread to this os thread
3412 JavaThread* main_thread = new JavaThread();
3413 main_thread->set_thread_state(_thread_in_vm);
3414 // must do this before set_active_handles and initialize_thread_local_storage
3415 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3416 // change the stack size recorded here to one based on the java thread
3417 // stacksize. This adjusted size is what is used to figure the placement
3418 // of the guard pages.
3419 main_thread->record_stack_base_and_size();
3420 main_thread->initialize_thread_local_storage();
3422 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3424 if (!main_thread->set_as_starting_thread()) {
3425 vm_shutdown_during_initialization(
3426 "Failed necessary internal allocation. Out of swap space");
3427 delete main_thread;
3428 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3429 return JNI_ENOMEM;
3430 }
3432 // Enable guard page *after* os::create_main_thread(), otherwise it would
3433 // crash Linux VM, see notes in os_linux.cpp.
3434 main_thread->create_stack_guard_pages();
3436 // Initialize Java-Level synchronization subsystem
3437 ObjectMonitor::Initialize() ;
3439 // Initialize global modules
3440 jint status = init_globals();
3441 if (status != JNI_OK) {
3442 delete main_thread;
3443 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3444 return status;
3445 }
3447 #if defined MIPS && !defined ZERO
3448 /* 2013/11/5 Jin: To be accessed in NativeGeneralJump::patch_verified_entry() */
3449 main_thread->set_handle_wrong_method_stub(SharedRuntime::get_handle_wrong_method_stub());
3450 #endif
3452 // Should be done after the heap is fully created
3453 main_thread->cache_global_variables();
3455 HandleMark hm;
3457 { MutexLocker mu(Threads_lock);
3458 Threads::add(main_thread);
3459 }
3461 // Any JVMTI raw monitors entered in onload will transition into
3462 // real raw monitor. VM is setup enough here for raw monitor enter.
3463 JvmtiExport::transition_pending_onload_raw_monitors();
3465 // Create the VMThread
3466 { TraceTime timer("Start VMThread", TraceStartupTime);
3467 VMThread::create();
3468 Thread* vmthread = VMThread::vm_thread();
3470 if (!os::create_thread(vmthread, os::vm_thread))
3471 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3473 // Wait for the VM thread to become ready, and VMThread::run to initialize
3474 // Monitors can have spurious returns, must always check another state flag
3475 {
3476 MutexLocker ml(Notify_lock);
3477 os::start_thread(vmthread);
3478 while (vmthread->active_handles() == NULL) {
3479 Notify_lock->wait();
3480 }
3481 }
3482 }
3484 assert (Universe::is_fully_initialized(), "not initialized");
3485 if (VerifyDuringStartup) {
3486 // Make sure we're starting with a clean slate.
3487 VM_Verify verify_op;
3488 VMThread::execute(&verify_op);
3489 }
3491 EXCEPTION_MARK;
3493 // At this point, the Universe is initialized, but we have not executed
3494 // any byte code. Now is a good time (the only time) to dump out the
3495 // internal state of the JVM for sharing.
3496 if (DumpSharedSpaces) {
3497 MetaspaceShared::preload_and_dump(CHECK_0);
3498 ShouldNotReachHere();
3499 }
3501 // Always call even when there are not JVMTI environments yet, since environments
3502 // may be attached late and JVMTI must track phases of VM execution
3503 JvmtiExport::enter_start_phase();
3505 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3506 JvmtiExport::post_vm_start();
3508 {
3509 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3511 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3512 create_vm_init_libraries();
3513 }
3515 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3517 // Initialize java_lang.System (needed before creating the thread)
3518 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3519 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3520 Handle thread_group = create_initial_thread_group(CHECK_0);
3521 Universe::set_main_thread_group(thread_group());
3522 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3523 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3524 main_thread->set_threadObj(thread_object);
3525 // Set thread status to running since main thread has
3526 // been started and running.
3527 java_lang_Thread::set_thread_status(thread_object,
3528 java_lang_Thread::RUNNABLE);
3530 // The VM creates & returns objects of this class. Make sure it's initialized.
3531 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3533 // The VM preresolves methods to these classes. Make sure that they get initialized
3534 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3535 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3536 call_initializeSystemClass(CHECK_0);
3538 // get the Java runtime name after java.lang.System is initialized
3539 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3540 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3542 // an instance of OutOfMemory exception has been allocated earlier
3543 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3544 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3545 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3546 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3547 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3548 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3549 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3550 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3551 }
3553 // See : bugid 4211085.
3554 // Background : the static initializer of java.lang.Compiler tries to read
3555 // property"java.compiler" and read & write property "java.vm.info".
3556 // When a security manager is installed through the command line
3557 // option "-Djava.security.manager", the above properties are not
3558 // readable and the static initializer for java.lang.Compiler fails
3559 // resulting in a NoClassDefFoundError. This can happen in any
3560 // user code which calls methods in java.lang.Compiler.
3561 // Hack : the hack is to pre-load and initialize this class, so that only
3562 // system domains are on the stack when the properties are read.
3563 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3564 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3565 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3566 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3567 // Once that is done, we should remove this hack.
3568 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3570 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3571 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3572 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3573 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3574 // This should also be taken out as soon as 4211383 gets fixed.
3575 reset_vm_info_property(CHECK_0);
3577 quicken_jni_functions();
3579 // Must be run after init_ft which initializes ft_enabled
3580 if (TRACE_INITIALIZE() != JNI_OK) {
3581 vm_exit_during_initialization("Failed to initialize tracing backend");
3582 }
3584 // Set flag that basic initialization has completed. Used by exceptions and various
3585 // debug stuff, that does not work until all basic classes have been initialized.
3586 set_init_completed();
3588 Metaspace::post_initialize();
3590 #ifndef USDT2
3591 HS_DTRACE_PROBE(hotspot, vm__init__end);
3592 #else /* USDT2 */
3593 HOTSPOT_VM_INIT_END();
3594 #endif /* USDT2 */
3596 // record VM initialization completion time
3597 #if INCLUDE_MANAGEMENT
3598 Management::record_vm_init_completed();
3599 #endif // INCLUDE_MANAGEMENT
3601 // Compute system loader. Note that this has to occur after set_init_completed, since
3602 // valid exceptions may be thrown in the process.
3603 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3604 // set_init_completed has just been called, causing exceptions not to be shortcut
3605 // anymore. We call vm_exit_during_initialization directly instead.
3606 SystemDictionary::compute_java_system_loader(THREAD);
3607 if (HAS_PENDING_EXCEPTION) {
3608 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3609 }
3611 #if INCLUDE_ALL_GCS
3612 // Support for ConcurrentMarkSweep. This should be cleaned up
3613 // and better encapsulated. The ugly nested if test would go away
3614 // once things are properly refactored. XXX YSR
3615 if (UseConcMarkSweepGC || UseG1GC) {
3616 if (UseConcMarkSweepGC) {
3617 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3618 } else {
3619 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3620 }
3621 if (HAS_PENDING_EXCEPTION) {
3622 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3623 }
3624 }
3625 #endif // INCLUDE_ALL_GCS
3627 // Always call even when there are not JVMTI environments yet, since environments
3628 // may be attached late and JVMTI must track phases of VM execution
3629 JvmtiExport::enter_live_phase();
3631 // Signal Dispatcher needs to be started before VMInit event is posted
3632 os::signal_init();
3634 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3635 if (!DisableAttachMechanism) {
3636 AttachListener::vm_start();
3637 if (StartAttachListener || AttachListener::init_at_startup()) {
3638 AttachListener::init();
3639 }
3640 }
3642 // Launch -Xrun agents
3643 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3644 // back-end can launch with -Xdebug -Xrunjdwp.
3645 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3646 create_vm_init_libraries();
3647 }
3649 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3650 JvmtiExport::post_vm_initialized();
3652 if (TRACE_START() != JNI_OK) {
3653 vm_exit_during_initialization("Failed to start tracing backend.");
3654 }
3656 if (CleanChunkPoolAsync) {
3657 Chunk::start_chunk_pool_cleaner_task();
3658 }
3660 // initialize compiler(s)
3661 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3662 CompileBroker::compilation_init();
3663 #endif
3665 if (EnableInvokeDynamic) {
3666 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3667 // It is done after compilers are initialized, because otherwise compilations of
3668 // signature polymorphic MH intrinsics can be missed
3669 // (see SystemDictionary::find_method_handle_intrinsic).
3670 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3671 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3672 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3673 }
3675 #if INCLUDE_MANAGEMENT
3676 Management::initialize(THREAD);
3677 #endif // INCLUDE_MANAGEMENT
3679 if (HAS_PENDING_EXCEPTION) {
3680 // management agent fails to start possibly due to
3681 // configuration problem and is responsible for printing
3682 // stack trace if appropriate. Simply exit VM.
3683 vm_exit(1);
3684 }
3686 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3687 if (MemProfiling) MemProfiler::engage();
3688 StatSampler::engage();
3689 if (CheckJNICalls) JniPeriodicChecker::engage();
3691 BiasedLocking::init();
3693 #if INCLUDE_RTM_OPT
3694 RTMLockingCounters::init();
3695 #endif
3697 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3698 call_postVMInitHook(THREAD);
3699 // The Java side of PostVMInitHook.run must deal with all
3700 // exceptions and provide means of diagnosis.
3701 if (HAS_PENDING_EXCEPTION) {
3702 CLEAR_PENDING_EXCEPTION;
3703 }
3704 }
3706 {
3707 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3708 // Make sure the watcher thread can be started by WatcherThread::start()
3709 // or by dynamic enrollment.
3710 WatcherThread::make_startable();
3711 // Start up the WatcherThread if there are any periodic tasks
3712 // NOTE: All PeriodicTasks should be registered by now. If they
3713 // aren't, late joiners might appear to start slowly (we might
3714 // take a while to process their first tick).
3715 if (PeriodicTask::num_tasks() > 0) {
3716 WatcherThread::start();
3717 }
3718 }
3720 create_vm_timer.end();
3721 #ifdef ASSERT
3722 _vm_complete = true;
3723 #endif
3724 return JNI_OK;
3725 }
3727 // type for the Agent_OnLoad and JVM_OnLoad entry points
3728 extern "C" {
3729 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3730 }
3731 // Find a command line agent library and return its entry point for
3732 // -agentlib: -agentpath: -Xrun
3733 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3734 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3735 OnLoadEntry_t on_load_entry = NULL;
3736 void *library = NULL;
3738 if (!agent->valid()) {
3739 char buffer[JVM_MAXPATHLEN];
3740 char ebuf[1024];
3741 const char *name = agent->name();
3742 const char *msg = "Could not find agent library ";
3744 // First check to see if agent is statically linked into executable
3745 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3746 library = agent->os_lib();
3747 } else if (agent->is_absolute_path()) {
3748 library = os::dll_load(name, ebuf, sizeof ebuf);
3749 if (library == NULL) {
3750 const char *sub_msg = " in absolute path, with error: ";
3751 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3752 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3753 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3754 // If we can't find the agent, exit.
3755 vm_exit_during_initialization(buf, NULL);
3756 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3757 }
3758 } else {
3759 // Try to load the agent from the standard dll directory
3760 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3761 name)) {
3762 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3763 }
3764 if (library == NULL) { // Try the local directory
3765 char ns[1] = {0};
3766 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3767 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3768 }
3769 if (library == NULL) {
3770 const char *sub_msg = " on the library path, with error: ";
3771 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3772 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3773 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3774 // If we can't find the agent, exit.
3775 vm_exit_during_initialization(buf, NULL);
3776 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3777 }
3778 }
3779 }
3780 agent->set_os_lib(library);
3781 agent->set_valid();
3782 }
3784 // Find the OnLoad function.
3785 on_load_entry =
3786 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3787 false,
3788 on_load_symbols,
3789 num_symbol_entries));
3790 return on_load_entry;
3791 }
3793 // Find the JVM_OnLoad entry point
3794 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3795 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3796 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3797 }
3799 // Find the Agent_OnLoad entry point
3800 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3801 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3802 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3803 }
3805 // For backwards compatibility with -Xrun
3806 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3807 // treated like -agentpath:
3808 // Must be called before agent libraries are created
3809 void Threads::convert_vm_init_libraries_to_agents() {
3810 AgentLibrary* agent;
3811 AgentLibrary* next;
3813 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3814 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3815 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3817 // If there is an JVM_OnLoad function it will get called later,
3818 // otherwise see if there is an Agent_OnLoad
3819 if (on_load_entry == NULL) {
3820 on_load_entry = lookup_agent_on_load(agent);
3821 if (on_load_entry != NULL) {
3822 // switch it to the agent list -- so that Agent_OnLoad will be called,
3823 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3824 Arguments::convert_library_to_agent(agent);
3825 } else {
3826 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3827 }
3828 }
3829 }
3830 }
3832 // Create agents for -agentlib: -agentpath: and converted -Xrun
3833 // Invokes Agent_OnLoad
3834 // Called very early -- before JavaThreads exist
3835 void Threads::create_vm_init_agents() {
3836 extern struct JavaVM_ main_vm;
3837 AgentLibrary* agent;
3839 JvmtiExport::enter_onload_phase();
3841 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3842 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3844 if (on_load_entry != NULL) {
3845 // Invoke the Agent_OnLoad function
3846 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3847 if (err != JNI_OK) {
3848 vm_exit_during_initialization("agent library failed to init", agent->name());
3849 }
3850 } else {
3851 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3852 }
3853 }
3854 JvmtiExport::enter_primordial_phase();
3855 }
3857 extern "C" {
3858 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3859 }
3861 void Threads::shutdown_vm_agents() {
3862 // Send any Agent_OnUnload notifications
3863 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3864 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3865 extern struct JavaVM_ main_vm;
3866 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3868 // Find the Agent_OnUnload function.
3869 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3870 os::find_agent_function(agent,
3871 false,
3872 on_unload_symbols,
3873 num_symbol_entries));
3875 // Invoke the Agent_OnUnload function
3876 if (unload_entry != NULL) {
3877 JavaThread* thread = JavaThread::current();
3878 ThreadToNativeFromVM ttn(thread);
3879 HandleMark hm(thread);
3880 (*unload_entry)(&main_vm);
3881 }
3882 }
3883 }
3885 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3886 // Invokes JVM_OnLoad
3887 void Threads::create_vm_init_libraries() {
3888 extern struct JavaVM_ main_vm;
3889 AgentLibrary* agent;
3891 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3892 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3894 if (on_load_entry != NULL) {
3895 // Invoke the JVM_OnLoad function
3896 JavaThread* thread = JavaThread::current();
3897 ThreadToNativeFromVM ttn(thread);
3898 HandleMark hm(thread);
3899 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3900 if (err != JNI_OK) {
3901 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3902 }
3903 } else {
3904 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3905 }
3906 }
3907 }
3909 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3910 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3912 JavaThread* java_thread = NULL;
3913 // Sequential search for now. Need to do better optimization later.
3914 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3915 oop tobj = thread->threadObj();
3916 if (!thread->is_exiting() &&
3917 tobj != NULL &&
3918 java_tid == java_lang_Thread::thread_id(tobj)) {
3919 java_thread = thread;
3920 break;
3921 }
3922 }
3923 return java_thread;
3924 }
3927 // Last thread running calls java.lang.Shutdown.shutdown()
3928 void JavaThread::invoke_shutdown_hooks() {
3929 HandleMark hm(this);
3931 // We could get here with a pending exception, if so clear it now.
3932 if (this->has_pending_exception()) {
3933 this->clear_pending_exception();
3934 }
3936 EXCEPTION_MARK;
3937 Klass* k =
3938 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3939 THREAD);
3940 if (k != NULL) {
3941 // SystemDictionary::resolve_or_null will return null if there was
3942 // an exception. If we cannot load the Shutdown class, just don't
3943 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3944 // and finalizers (if runFinalizersOnExit is set) won't be run.
3945 // Note that if a shutdown hook was registered or runFinalizersOnExit
3946 // was called, the Shutdown class would have already been loaded
3947 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3948 instanceKlassHandle shutdown_klass (THREAD, k);
3949 JavaValue result(T_VOID);
3950 JavaCalls::call_static(&result,
3951 shutdown_klass,
3952 vmSymbols::shutdown_method_name(),
3953 vmSymbols::void_method_signature(),
3954 THREAD);
3955 }
3956 CLEAR_PENDING_EXCEPTION;
3957 }
3959 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3960 // the program falls off the end of main(). Another VM exit path is through
3961 // vm_exit() when the program calls System.exit() to return a value or when
3962 // there is a serious error in VM. The two shutdown paths are not exactly
3963 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3964 // and VM_Exit op at VM level.
3965 //
3966 // Shutdown sequence:
3967 // + Shutdown native memory tracking if it is on
3968 // + Wait until we are the last non-daemon thread to execute
3969 // <-- every thing is still working at this moment -->
3970 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3971 // shutdown hooks, run finalizers if finalization-on-exit
3972 // + Call before_exit(), prepare for VM exit
3973 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3974 // currently the only user of this mechanism is File.deleteOnExit())
3975 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3976 // post thread end and vm death events to JVMTI,
3977 // stop signal thread
3978 // + Call JavaThread::exit(), it will:
3979 // > release JNI handle blocks, remove stack guard pages
3980 // > remove this thread from Threads list
3981 // <-- no more Java code from this thread after this point -->
3982 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3983 // the compiler threads at safepoint
3984 // <-- do not use anything that could get blocked by Safepoint -->
3985 // + Disable tracing at JNI/JVM barriers
3986 // + Set _vm_exited flag for threads that are still running native code
3987 // + Delete this thread
3988 // + Call exit_globals()
3989 // > deletes tty
3990 // > deletes PerfMemory resources
3991 // + Return to caller
3993 bool Threads::destroy_vm() {
3994 JavaThread* thread = JavaThread::current();
3996 #ifdef ASSERT
3997 _vm_complete = false;
3998 #endif
3999 // Wait until we are the last non-daemon thread to execute
4000 { MutexLocker nu(Threads_lock);
4001 while (Threads::number_of_non_daemon_threads() > 1 )
4002 // This wait should make safepoint checks, wait without a timeout,
4003 // and wait as a suspend-equivalent condition.
4004 //
4005 // Note: If the FlatProfiler is running and this thread is waiting
4006 // for another non-daemon thread to finish, then the FlatProfiler
4007 // is waiting for the external suspend request on this thread to
4008 // complete. wait_for_ext_suspend_completion() will eventually
4009 // timeout, but that takes time. Making this wait a suspend-
4010 // equivalent condition solves that timeout problem.
4011 //
4012 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4013 Mutex::_as_suspend_equivalent_flag);
4014 }
4016 // Hang forever on exit if we are reporting an error.
4017 if (ShowMessageBoxOnError && is_error_reported()) {
4018 os::infinite_sleep();
4019 }
4020 os::wait_for_keypress_at_exit();
4022 if (JDK_Version::is_jdk12x_version()) {
4023 // We are the last thread running, so check if finalizers should be run.
4024 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4025 HandleMark rm(thread);
4026 Universe::run_finalizers_on_exit();
4027 } else {
4028 // run Java level shutdown hooks
4029 thread->invoke_shutdown_hooks();
4030 }
4032 before_exit(thread);
4034 thread->exit(true);
4036 // Stop VM thread.
4037 {
4038 // 4945125 The vm thread comes to a safepoint during exit.
4039 // GC vm_operations can get caught at the safepoint, and the
4040 // heap is unparseable if they are caught. Grab the Heap_lock
4041 // to prevent this. The GC vm_operations will not be able to
4042 // queue until after the vm thread is dead. After this point,
4043 // we'll never emerge out of the safepoint before the VM exits.
4045 MutexLocker ml(Heap_lock);
4047 VMThread::wait_for_vm_thread_exit();
4048 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4049 VMThread::destroy();
4050 }
4052 // clean up ideal graph printers
4053 #if defined(COMPILER2) && !defined(PRODUCT)
4054 IdealGraphPrinter::clean_up();
4055 #endif
4057 // Now, all Java threads are gone except daemon threads. Daemon threads
4058 // running Java code or in VM are stopped by the Safepoint. However,
4059 // daemon threads executing native code are still running. But they
4060 // will be stopped at native=>Java/VM barriers. Note that we can't
4061 // simply kill or suspend them, as it is inherently deadlock-prone.
4063 #ifndef PRODUCT
4064 // disable function tracing at JNI/JVM barriers
4065 TraceJNICalls = false;
4066 TraceJVMCalls = false;
4067 TraceRuntimeCalls = false;
4068 #endif
4070 VM_Exit::set_vm_exited();
4072 notify_vm_shutdown();
4074 delete thread;
4076 // exit_globals() will delete tty
4077 exit_globals();
4079 return true;
4080 }
4083 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4084 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4085 return is_supported_jni_version(version);
4086 }
4089 jboolean Threads::is_supported_jni_version(jint version) {
4090 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4091 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4092 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4093 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4094 return JNI_FALSE;
4095 }
4098 void Threads::add(JavaThread* p, bool force_daemon) {
4099 // The threads lock must be owned at this point
4100 assert_locked_or_safepoint(Threads_lock);
4102 // See the comment for this method in thread.hpp for its purpose and
4103 // why it is called here.
4104 p->initialize_queues();
4105 p->set_next(_thread_list);
4106 _thread_list = p;
4107 _number_of_threads++;
4108 oop threadObj = p->threadObj();
4109 bool daemon = true;
4110 // Bootstrapping problem: threadObj can be null for initial
4111 // JavaThread (or for threads attached via JNI)
4112 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4113 _number_of_non_daemon_threads++;
4114 daemon = false;
4115 }
4117 ThreadService::add_thread(p, daemon);
4119 // Possible GC point.
4120 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4121 }
4123 void Threads::remove(JavaThread* p) {
4124 // Extra scope needed for Thread_lock, so we can check
4125 // that we do not remove thread without safepoint code notice
4126 { MutexLocker ml(Threads_lock);
4128 assert(includes(p), "p must be present");
4130 JavaThread* current = _thread_list;
4131 JavaThread* prev = NULL;
4133 while (current != p) {
4134 prev = current;
4135 current = current->next();
4136 }
4138 if (prev) {
4139 prev->set_next(current->next());
4140 } else {
4141 _thread_list = p->next();
4142 }
4143 _number_of_threads--;
4144 oop threadObj = p->threadObj();
4145 bool daemon = true;
4146 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4147 _number_of_non_daemon_threads--;
4148 daemon = false;
4150 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4151 // on destroy_vm will wake up.
4152 if (number_of_non_daemon_threads() == 1)
4153 Threads_lock->notify_all();
4154 }
4155 ThreadService::remove_thread(p, daemon);
4157 // Make sure that safepoint code disregard this thread. This is needed since
4158 // the thread might mess around with locks after this point. This can cause it
4159 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4160 // of this thread since it is removed from the queue.
4161 p->set_terminated_value();
4162 } // unlock Threads_lock
4164 // Since Events::log uses a lock, we grab it outside the Threads_lock
4165 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4166 }
4168 // Threads_lock must be held when this is called (or must be called during a safepoint)
4169 bool Threads::includes(JavaThread* p) {
4170 assert(Threads_lock->is_locked(), "sanity check");
4171 ALL_JAVA_THREADS(q) {
4172 if (q == p ) {
4173 return true;
4174 }
4175 }
4176 return false;
4177 }
4179 // Operations on the Threads list for GC. These are not explicitly locked,
4180 // but the garbage collector must provide a safe context for them to run.
4181 // In particular, these things should never be called when the Threads_lock
4182 // is held by some other thread. (Note: the Safepoint abstraction also
4183 // uses the Threads_lock to gurantee this property. It also makes sure that
4184 // all threads gets blocked when exiting or starting).
4186 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4187 ALL_JAVA_THREADS(p) {
4188 p->oops_do(f, cld_f, cf);
4189 }
4190 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4191 }
4193 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4194 // Introduce a mechanism allowing parallel threads to claim threads as
4195 // root groups. Overhead should be small enough to use all the time,
4196 // even in sequential code.
4197 SharedHeap* sh = SharedHeap::heap();
4198 // Cannot yet substitute active_workers for n_par_threads
4199 // because of G1CollectedHeap::verify() use of
4200 // SharedHeap::process_roots(). n_par_threads == 0 will
4201 // turn off parallelism in process_roots while active_workers
4202 // is being used for parallelism elsewhere.
4203 bool is_par = sh->n_par_threads() > 0;
4204 assert(!is_par ||
4205 (SharedHeap::heap()->n_par_threads() ==
4206 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4207 int cp = SharedHeap::heap()->strong_roots_parity();
4208 ALL_JAVA_THREADS(p) {
4209 if (p->claim_oops_do(is_par, cp)) {
4210 p->oops_do(f, cld_f, cf);
4211 }
4212 }
4213 VMThread* vmt = VMThread::vm_thread();
4214 if (vmt->claim_oops_do(is_par, cp)) {
4215 vmt->oops_do(f, cld_f, cf);
4216 }
4217 }
4219 #if INCLUDE_ALL_GCS
4220 // Used by ParallelScavenge
4221 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4222 ALL_JAVA_THREADS(p) {
4223 q->enqueue(new ThreadRootsTask(p));
4224 }
4225 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4226 }
4228 // Used by Parallel Old
4229 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4230 ALL_JAVA_THREADS(p) {
4231 q->enqueue(new ThreadRootsMarkingTask(p));
4232 }
4233 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4234 }
4235 #endif // INCLUDE_ALL_GCS
4237 void Threads::nmethods_do(CodeBlobClosure* cf) {
4238 ALL_JAVA_THREADS(p) {
4239 p->nmethods_do(cf);
4240 }
4241 VMThread::vm_thread()->nmethods_do(cf);
4242 }
4244 void Threads::metadata_do(void f(Metadata*)) {
4245 ALL_JAVA_THREADS(p) {
4246 p->metadata_do(f);
4247 }
4248 }
4250 void Threads::gc_epilogue() {
4251 ALL_JAVA_THREADS(p) {
4252 p->gc_epilogue();
4253 }
4254 }
4256 void Threads::gc_prologue() {
4257 ALL_JAVA_THREADS(p) {
4258 p->gc_prologue();
4259 }
4260 }
4262 void Threads::deoptimized_wrt_marked_nmethods() {
4263 ALL_JAVA_THREADS(p) {
4264 p->deoptimized_wrt_marked_nmethods();
4265 }
4266 }
4269 // Get count Java threads that are waiting to enter the specified monitor.
4270 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4271 address monitor, bool doLock) {
4272 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4273 "must grab Threads_lock or be at safepoint");
4274 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4276 int i = 0;
4277 {
4278 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4279 ALL_JAVA_THREADS(p) {
4280 if (p->is_Compiler_thread()) continue;
4282 address pending = (address)p->current_pending_monitor();
4283 if (pending == monitor) { // found a match
4284 if (i < count) result->append(p); // save the first count matches
4285 i++;
4286 }
4287 }
4288 }
4289 return result;
4290 }
4293 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4294 assert(doLock ||
4295 Threads_lock->owned_by_self() ||
4296 SafepointSynchronize::is_at_safepoint(),
4297 "must grab Threads_lock or be at safepoint");
4299 // NULL owner means not locked so we can skip the search
4300 if (owner == NULL) return NULL;
4302 {
4303 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4304 ALL_JAVA_THREADS(p) {
4305 // first, see if owner is the address of a Java thread
4306 if (owner == (address)p) return p;
4307 }
4308 }
4309 // Cannot assert on lack of success here since this function may be
4310 // used by code that is trying to report useful problem information
4311 // like deadlock detection.
4312 if (UseHeavyMonitors) return NULL;
4314 //
4315 // If we didn't find a matching Java thread and we didn't force use of
4316 // heavyweight monitors, then the owner is the stack address of the
4317 // Lock Word in the owning Java thread's stack.
4318 //
4319 JavaThread* the_owner = NULL;
4320 {
4321 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4322 ALL_JAVA_THREADS(q) {
4323 if (q->is_lock_owned(owner)) {
4324 the_owner = q;
4325 break;
4326 }
4327 }
4328 }
4329 // cannot assert on lack of success here; see above comment
4330 return the_owner;
4331 }
4333 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4334 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4335 char buf[32];
4336 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4338 st->print_cr("Full thread dump %s (%s %s):",
4339 Abstract_VM_Version::vm_name(),
4340 Abstract_VM_Version::vm_release(),
4341 Abstract_VM_Version::vm_info_string()
4342 );
4343 st->cr();
4345 #if INCLUDE_ALL_GCS
4346 // Dump concurrent locks
4347 ConcurrentLocksDump concurrent_locks;
4348 if (print_concurrent_locks) {
4349 concurrent_locks.dump_at_safepoint();
4350 }
4351 #endif // INCLUDE_ALL_GCS
4353 ALL_JAVA_THREADS(p) {
4354 ResourceMark rm;
4355 p->print_on(st);
4356 if (print_stacks) {
4357 if (internal_format) {
4358 p->trace_stack();
4359 } else {
4360 p->print_stack_on(st);
4361 }
4362 }
4363 st->cr();
4364 #if INCLUDE_ALL_GCS
4365 if (print_concurrent_locks) {
4366 concurrent_locks.print_locks_on(p, st);
4367 }
4368 #endif // INCLUDE_ALL_GCS
4369 }
4371 VMThread::vm_thread()->print_on(st);
4372 st->cr();
4373 Universe::heap()->print_gc_threads_on(st);
4374 WatcherThread* wt = WatcherThread::watcher_thread();
4375 if (wt != NULL) {
4376 wt->print_on(st);
4377 st->cr();
4378 }
4379 CompileBroker::print_compiler_threads_on(st);
4380 st->flush();
4381 }
4383 // Threads::print_on_error() is called by fatal error handler. It's possible
4384 // that VM is not at safepoint and/or current thread is inside signal handler.
4385 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4386 // memory (even in resource area), it might deadlock the error handler.
4387 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4388 bool found_current = false;
4389 st->print_cr("Java Threads: ( => current thread )");
4390 ALL_JAVA_THREADS(thread) {
4391 bool is_current = (current == thread);
4392 found_current = found_current || is_current;
4394 st->print("%s", is_current ? "=>" : " ");
4396 st->print(PTR_FORMAT, thread);
4397 st->print(" ");
4398 thread->print_on_error(st, buf, buflen);
4399 st->cr();
4400 }
4401 st->cr();
4403 st->print_cr("Other Threads:");
4404 if (VMThread::vm_thread()) {
4405 bool is_current = (current == VMThread::vm_thread());
4406 found_current = found_current || is_current;
4407 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4409 st->print(PTR_FORMAT, VMThread::vm_thread());
4410 st->print(" ");
4411 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4412 st->cr();
4413 }
4414 WatcherThread* wt = WatcherThread::watcher_thread();
4415 if (wt != NULL) {
4416 bool is_current = (current == wt);
4417 found_current = found_current || is_current;
4418 st->print("%s", is_current ? "=>" : " ");
4420 st->print(PTR_FORMAT, wt);
4421 st->print(" ");
4422 wt->print_on_error(st, buf, buflen);
4423 st->cr();
4424 }
4425 if (!found_current) {
4426 st->cr();
4427 st->print("=>" PTR_FORMAT " (exited) ", current);
4428 current->print_on_error(st, buf, buflen);
4429 st->cr();
4430 }
4431 }
4433 // Internal SpinLock and Mutex
4434 // Based on ParkEvent
4436 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4437 //
4438 // We employ SpinLocks _only for low-contention, fixed-length
4439 // short-duration critical sections where we're concerned
4440 // about native mutex_t or HotSpot Mutex:: latency.
4441 // The mux construct provides a spin-then-block mutual exclusion
4442 // mechanism.
4443 //
4444 // Testing has shown that contention on the ListLock guarding gFreeList
4445 // is common. If we implement ListLock as a simple SpinLock it's common
4446 // for the JVM to devolve to yielding with little progress. This is true
4447 // despite the fact that the critical sections protected by ListLock are
4448 // extremely short.
4449 //
4450 // TODO-FIXME: ListLock should be of type SpinLock.
4451 // We should make this a 1st-class type, integrated into the lock
4452 // hierarchy as leaf-locks. Critically, the SpinLock structure
4453 // should have sufficient padding to avoid false-sharing and excessive
4454 // cache-coherency traffic.
4457 typedef volatile int SpinLockT ;
4459 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4460 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4461 return ; // normal fast-path return
4462 }
4464 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4465 TEVENT (SpinAcquire - ctx) ;
4466 int ctr = 0 ;
4467 int Yields = 0 ;
4468 for (;;) {
4469 while (*adr != 0) {
4470 ++ctr ;
4471 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4472 if (Yields > 5) {
4473 os::naked_short_sleep(1);
4474 } else {
4475 os::NakedYield() ;
4476 ++Yields ;
4477 }
4478 } else {
4479 SpinPause() ;
4480 }
4481 }
4482 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4483 }
4484 }
4486 void Thread::SpinRelease (volatile int * adr) {
4487 assert (*adr != 0, "invariant") ;
4488 OrderAccess::fence() ; // guarantee at least release consistency.
4489 // Roach-motel semantics.
4490 // It's safe if subsequent LDs and STs float "up" into the critical section,
4491 // but prior LDs and STs within the critical section can't be allowed
4492 // to reorder or float past the ST that releases the lock.
4493 *adr = 0 ;
4494 }
4496 // muxAcquire and muxRelease:
4497 //
4498 // * muxAcquire and muxRelease support a single-word lock-word construct.
4499 // The LSB of the word is set IFF the lock is held.
4500 // The remainder of the word points to the head of a singly-linked list
4501 // of threads blocked on the lock.
4502 //
4503 // * The current implementation of muxAcquire-muxRelease uses its own
4504 // dedicated Thread._MuxEvent instance. If we're interested in
4505 // minimizing the peak number of extant ParkEvent instances then
4506 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4507 // as certain invariants were satisfied. Specifically, care would need
4508 // to be taken with regards to consuming unpark() "permits".
4509 // A safe rule of thumb is that a thread would never call muxAcquire()
4510 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4511 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4512 // consume an unpark() permit intended for monitorenter, for instance.
4513 // One way around this would be to widen the restricted-range semaphore
4514 // implemented in park(). Another alternative would be to provide
4515 // multiple instances of the PlatformEvent() for each thread. One
4516 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4517 //
4518 // * Usage:
4519 // -- Only as leaf locks
4520 // -- for short-term locking only as muxAcquire does not perform
4521 // thread state transitions.
4522 //
4523 // Alternatives:
4524 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4525 // but with parking or spin-then-park instead of pure spinning.
4526 // * Use Taura-Oyama-Yonenzawa locks.
4527 // * It's possible to construct a 1-0 lock if we encode the lockword as
4528 // (List,LockByte). Acquire will CAS the full lockword while Release
4529 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4530 // acquiring threads use timers (ParkTimed) to detect and recover from
4531 // the stranding window. Thread/Node structures must be aligned on 256-byte
4532 // boundaries by using placement-new.
4533 // * Augment MCS with advisory back-link fields maintained with CAS().
4534 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4535 // The validity of the backlinks must be ratified before we trust the value.
4536 // If the backlinks are invalid the exiting thread must back-track through the
4537 // the forward links, which are always trustworthy.
4538 // * Add a successor indication. The LockWord is currently encoded as
4539 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4540 // to provide the usual futile-wakeup optimization.
4541 // See RTStt for details.
4542 // * Consider schedctl.sc_nopreempt to cover the critical section.
4543 //
4546 typedef volatile intptr_t MutexT ; // Mux Lock-word
4547 enum MuxBits { LOCKBIT = 1 } ;
4549 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4550 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4551 if (w == 0) return ;
4552 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4553 return ;
4554 }
4556 TEVENT (muxAcquire - Contention) ;
4557 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4558 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4559 for (;;) {
4560 int its = (os::is_MP() ? 100 : 0) + 1 ;
4562 // Optional spin phase: spin-then-park strategy
4563 while (--its >= 0) {
4564 w = *Lock ;
4565 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4566 return ;
4567 }
4568 }
4570 Self->reset() ;
4571 Self->OnList = intptr_t(Lock) ;
4572 // The following fence() isn't _strictly necessary as the subsequent
4573 // CAS() both serializes execution and ratifies the fetched *Lock value.
4574 OrderAccess::fence();
4575 for (;;) {
4576 w = *Lock ;
4577 if ((w & LOCKBIT) == 0) {
4578 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4579 Self->OnList = 0 ; // hygiene - allows stronger asserts
4580 return ;
4581 }
4582 continue ; // Interference -- *Lock changed -- Just retry
4583 }
4584 assert (w & LOCKBIT, "invariant") ;
4585 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4586 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4587 }
4589 while (Self->OnList != 0) {
4590 Self->park() ;
4591 }
4592 }
4593 }
4595 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4596 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4597 if (w == 0) return ;
4598 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4599 return ;
4600 }
4602 TEVENT (muxAcquire - Contention) ;
4603 ParkEvent * ReleaseAfter = NULL ;
4604 if (ev == NULL) {
4605 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4606 }
4607 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4608 for (;;) {
4609 guarantee (ev->OnList == 0, "invariant") ;
4610 int its = (os::is_MP() ? 100 : 0) + 1 ;
4612 // Optional spin phase: spin-then-park strategy
4613 while (--its >= 0) {
4614 w = *Lock ;
4615 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4616 if (ReleaseAfter != NULL) {
4617 ParkEvent::Release (ReleaseAfter) ;
4618 }
4619 return ;
4620 }
4621 }
4623 ev->reset() ;
4624 ev->OnList = intptr_t(Lock) ;
4625 // The following fence() isn't _strictly necessary as the subsequent
4626 // CAS() both serializes execution and ratifies the fetched *Lock value.
4627 OrderAccess::fence();
4628 for (;;) {
4629 w = *Lock ;
4630 if ((w & LOCKBIT) == 0) {
4631 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4632 ev->OnList = 0 ;
4633 // We call ::Release while holding the outer lock, thus
4634 // artificially lengthening the critical section.
4635 // Consider deferring the ::Release() until the subsequent unlock(),
4636 // after we've dropped the outer lock.
4637 if (ReleaseAfter != NULL) {
4638 ParkEvent::Release (ReleaseAfter) ;
4639 }
4640 return ;
4641 }
4642 continue ; // Interference -- *Lock changed -- Just retry
4643 }
4644 assert (w & LOCKBIT, "invariant") ;
4645 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4646 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4647 }
4649 while (ev->OnList != 0) {
4650 ev->park() ;
4651 }
4652 }
4653 }
4655 // Release() must extract a successor from the list and then wake that thread.
4656 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4657 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4658 // Release() would :
4659 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4660 // (B) Extract a successor from the private list "in-hand"
4661 // (C) attempt to CAS() the residual back into *Lock over null.
4662 // If there were any newly arrived threads and the CAS() would fail.
4663 // In that case Release() would detach the RATs, re-merge the list in-hand
4664 // with the RATs and repeat as needed. Alternately, Release() might
4665 // detach and extract a successor, but then pass the residual list to the wakee.
4666 // The wakee would be responsible for reattaching and remerging before it
4667 // competed for the lock.
4668 //
4669 // Both "pop" and DMR are immune from ABA corruption -- there can be
4670 // multiple concurrent pushers, but only one popper or detacher.
4671 // This implementation pops from the head of the list. This is unfair,
4672 // but tends to provide excellent throughput as hot threads remain hot.
4673 // (We wake recently run threads first).
4675 void Thread::muxRelease (volatile intptr_t * Lock) {
4676 for (;;) {
4677 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4678 assert (w & LOCKBIT, "invariant") ;
4679 if (w == LOCKBIT) return ;
4680 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4681 assert (List != NULL, "invariant") ;
4682 assert (List->OnList == intptr_t(Lock), "invariant") ;
4683 ParkEvent * nxt = List->ListNext ;
4685 // The following CAS() releases the lock and pops the head element.
4686 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4687 continue ;
4688 }
4689 List->OnList = 0 ;
4690 OrderAccess::fence() ;
4691 List->unpark () ;
4692 return ;
4693 }
4694 }
4697 void Threads::verify() {
4698 ALL_JAVA_THREADS(p) {
4699 p->verify();
4700 }
4701 VMThread* thread = VMThread::vm_thread();
4702 if (thread != NULL) thread->verify();
4703 }