Wed, 14 Oct 2020 17:44:48 +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 "jfr/jfrEvents.hpp"
42 #include "jvmtifiles/jvmtiEnv.hpp"
43 #include "memory/gcLocker.inline.hpp"
44 #include "memory/metaspaceShared.hpp"
45 #include "memory/oopFactory.hpp"
46 #include "memory/universe.inline.hpp"
47 #include "oops/instanceKlass.hpp"
48 #include "oops/objArrayOop.hpp"
49 #include "oops/oop.inline.hpp"
50 #include "oops/symbol.hpp"
51 #include "prims/jvm_misc.hpp"
52 #include "prims/jvmtiExport.hpp"
53 #include "prims/jvmtiThreadState.hpp"
54 #include "prims/privilegedStack.hpp"
55 #include "runtime/arguments.hpp"
56 #include "runtime/biasedLocking.hpp"
57 #include "runtime/deoptimization.hpp"
58 #include "runtime/fprofiler.hpp"
59 #include "runtime/frame.inline.hpp"
60 #include "runtime/init.hpp"
61 #include "runtime/interfaceSupport.hpp"
62 #include "runtime/java.hpp"
63 #include "runtime/javaCalls.hpp"
64 #include "runtime/jniPeriodicChecker.hpp"
65 #include "runtime/memprofiler.hpp"
66 #include "runtime/mutexLocker.hpp"
67 #include "runtime/objectMonitor.hpp"
68 #include "runtime/orderAccess.inline.hpp"
69 #include "runtime/osThread.hpp"
70 #include "runtime/safepoint.hpp"
71 #include "runtime/sharedRuntime.hpp"
72 #include "runtime/statSampler.hpp"
73 #include "runtime/stubRoutines.hpp"
74 #include "runtime/task.hpp"
75 #include "runtime/thread.inline.hpp"
76 #include "runtime/threadCritical.hpp"
77 #include "runtime/threadLocalStorage.hpp"
78 #include "runtime/vframe.hpp"
79 #include "runtime/vframeArray.hpp"
80 #include "runtime/vframe_hp.hpp"
81 #include "runtime/vmThread.hpp"
82 #include "runtime/vm_operations.hpp"
83 #include "services/attachListener.hpp"
84 #include "services/management.hpp"
85 #include "services/memTracker.hpp"
86 #include "services/threadService.hpp"
87 #include "utilities/defaultStream.hpp"
88 #include "utilities/dtrace.hpp"
89 #include "utilities/events.hpp"
90 #include "utilities/preserveException.hpp"
91 #include "utilities/macros.hpp"
92 #ifdef TARGET_OS_FAMILY_linux
93 # include "os_linux.inline.hpp"
94 #endif
95 #ifdef TARGET_OS_FAMILY_solaris
96 # include "os_solaris.inline.hpp"
97 #endif
98 #ifdef TARGET_OS_FAMILY_windows
99 # include "os_windows.inline.hpp"
100 #endif
101 #ifdef TARGET_OS_FAMILY_bsd
102 # include "os_bsd.inline.hpp"
103 #endif
104 #if INCLUDE_ALL_GCS
105 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
106 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
107 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
108 #endif // INCLUDE_ALL_GCS
109 #ifdef COMPILER1
110 #include "c1/c1_Compiler.hpp"
111 #endif
112 #ifdef COMPILER2
113 #include "opto/c2compiler.hpp"
114 #include "opto/idealGraphPrinter.hpp"
115 #endif
116 #if INCLUDE_RTM_OPT
117 #include "runtime/rtmLocking.hpp"
118 #endif
119 #if INCLUDE_JFR
120 #include "jfr/jfr.hpp"
121 #endif
123 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
125 #ifdef DTRACE_ENABLED
127 // Only bother with this argument setup if dtrace is available
129 #ifndef USDT2
130 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
131 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
132 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
133 intptr_t, intptr_t, bool);
134 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
135 intptr_t, intptr_t, bool);
137 #define DTRACE_THREAD_PROBE(probe, javathread) \
138 { \
139 ResourceMark rm(this); \
140 int len = 0; \
141 const char* name = (javathread)->get_thread_name(); \
142 len = strlen(name); \
143 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
144 name, len, \
145 java_lang_Thread::thread_id((javathread)->threadObj()), \
146 (javathread)->osthread()->thread_id(), \
147 java_lang_Thread::is_daemon((javathread)->threadObj())); \
148 }
150 #else /* USDT2 */
152 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
153 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
155 #define DTRACE_THREAD_PROBE(probe, javathread) \
156 { \
157 ResourceMark rm(this); \
158 int len = 0; \
159 const char* name = (javathread)->get_thread_name(); \
160 len = strlen(name); \
161 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
162 (char *) name, len, \
163 java_lang_Thread::thread_id((javathread)->threadObj()), \
164 (uintptr_t) (javathread)->osthread()->thread_id(), \
165 java_lang_Thread::is_daemon((javathread)->threadObj())); \
166 }
168 #endif /* USDT2 */
170 #else // ndef DTRACE_ENABLED
172 #define DTRACE_THREAD_PROBE(probe, javathread)
174 #endif // ndef DTRACE_ENABLED
177 // Class hierarchy
178 // - Thread
179 // - VMThread
180 // - WatcherThread
181 // - ConcurrentMarkSweepThread
182 // - JavaThread
183 // - CompilerThread
185 // ======= Thread ========
186 // Support for forcing alignment of thread objects for biased locking
187 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
188 if (UseBiasedLocking) {
189 const int alignment = markOopDesc::biased_lock_alignment;
190 size_t aligned_size = size + (alignment - sizeof(intptr_t));
191 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
192 : AllocateHeap(aligned_size, flags, CURRENT_PC,
193 AllocFailStrategy::RETURN_NULL);
194 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
195 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
196 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
197 "JavaThread alignment code overflowed allocated storage");
198 if (TraceBiasedLocking) {
199 if (aligned_addr != real_malloc_addr)
200 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
201 real_malloc_addr, aligned_addr);
202 }
203 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
204 return aligned_addr;
205 } else {
206 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
207 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
208 }
209 }
211 void Thread::operator delete(void* p) {
212 if (UseBiasedLocking) {
213 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
214 FreeHeap(real_malloc_addr, mtThread);
215 } else {
216 FreeHeap(p, mtThread);
217 }
218 }
221 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
222 // JavaThread
225 Thread::Thread() {
226 // stack and get_thread
227 set_stack_base(NULL);
228 set_stack_size(0);
229 set_self_raw_id(0);
230 set_lgrp_id(-1);
232 // allocated data structures
233 set_osthread(NULL);
234 set_resource_area(new (mtThread)ResourceArea());
235 DEBUG_ONLY(_current_resource_mark = NULL;)
236 set_handle_area(new (mtThread) HandleArea(NULL));
237 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
238 set_active_handles(NULL);
239 set_free_handle_block(NULL);
240 set_last_handle_mark(NULL);
242 // This initial value ==> never claimed.
243 _oops_do_parity = 0;
245 _metadata_on_stack_buffer = NULL;
247 // the handle mark links itself to last_handle_mark
248 new HandleMark(this);
250 // plain initialization
251 debug_only(_owned_locks = NULL;)
252 debug_only(_allow_allocation_count = 0;)
253 NOT_PRODUCT(_allow_safepoint_count = 0;)
254 NOT_PRODUCT(_skip_gcalot = false;)
255 _jvmti_env_iteration_count = 0;
256 set_allocated_bytes(0);
257 _vm_operation_started_count = 0;
258 _vm_operation_completed_count = 0;
259 _current_pending_monitor = NULL;
260 _current_pending_monitor_is_from_java = true;
261 _current_waiting_monitor = NULL;
262 _num_nested_signal = 0;
263 omFreeList = NULL ;
264 omFreeCount = 0 ;
265 omFreeProvision = 32 ;
266 omInUseList = NULL ;
267 omInUseCount = 0 ;
269 #ifdef ASSERT
270 _visited_for_critical_count = false;
271 #endif
273 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
274 _suspend_flags = 0;
276 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
277 _hashStateX = os::random() ;
278 _hashStateY = 842502087 ;
279 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
280 _hashStateW = 273326509 ;
282 _OnTrap = 0 ;
283 _schedctl = NULL ;
284 _Stalled = 0 ;
285 _TypeTag = 0x2BAD ;
287 // Many of the following fields are effectively final - immutable
288 // Note that nascent threads can't use the Native Monitor-Mutex
289 // construct until the _MutexEvent is initialized ...
290 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
291 // we might instead use a stack of ParkEvents that we could provision on-demand.
292 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
293 // and ::Release()
294 _ParkEvent = ParkEvent::Allocate (this) ;
295 _SleepEvent = ParkEvent::Allocate (this) ;
296 _MutexEvent = ParkEvent::Allocate (this) ;
297 _MuxEvent = ParkEvent::Allocate (this) ;
299 #ifdef CHECK_UNHANDLED_OOPS
300 if (CheckUnhandledOops) {
301 _unhandled_oops = new UnhandledOops(this);
302 }
303 #endif // CHECK_UNHANDLED_OOPS
304 #ifdef ASSERT
305 if (UseBiasedLocking) {
306 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
307 assert(this == _real_malloc_address ||
308 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
309 "bug in forced alignment of thread objects");
310 }
311 #endif /* ASSERT */
312 }
314 void Thread::initialize_thread_local_storage() {
315 // Note: Make sure this method only calls
316 // non-blocking operations. Otherwise, it might not work
317 // with the thread-startup/safepoint interaction.
319 // During Java thread startup, safepoint code should allow this
320 // method to complete because it may need to allocate memory to
321 // store information for the new thread.
323 // initialize structure dependent on thread local storage
324 ThreadLocalStorage::set_thread(this);
325 }
327 void Thread::record_stack_base_and_size() {
328 set_stack_base(os::current_stack_base());
329 set_stack_size(os::current_stack_size());
330 if (is_Java_thread()) {
331 ((JavaThread*) this)->set_stack_overflow_limit();
332 }
333 // CR 7190089: on Solaris, primordial thread's stack is adjusted
334 // in initialize_thread(). Without the adjustment, stack size is
335 // incorrect if stack is set to unlimited (ulimit -s unlimited).
336 // So far, only Solaris has real implementation of initialize_thread().
337 //
338 // set up any platform-specific state.
339 os::initialize_thread(this);
341 #if INCLUDE_NMT
342 // record thread's native stack, stack grows downward
343 address stack_low_addr = stack_base() - stack_size();
344 MemTracker::record_thread_stack(stack_low_addr, stack_size());
345 #endif // INCLUDE_NMT
346 }
349 Thread::~Thread() {
350 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
351 ObjectSynchronizer::omFlush (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 if (active_handles() != NULL) {
846 active_handles()->oops_do(f);
847 }
848 // Do oop for ThreadShadow
849 f->do_oop((oop*)&_pending_exception);
850 handle_area()->oops_do(f);
851 }
853 void Thread::nmethods_do(CodeBlobClosure* cf) {
854 // no nmethods in a generic thread...
855 }
857 void Thread::metadata_do(void f(Metadata*)) {
858 if (metadata_handles() != NULL) {
859 for (int i = 0; i< metadata_handles()->length(); i++) {
860 f(metadata_handles()->at(i));
861 }
862 }
863 }
865 void Thread::print_on(outputStream* st) const {
866 // get_priority assumes osthread initialized
867 if (osthread() != NULL) {
868 int os_prio;
869 if (os::get_native_priority(this, &os_prio) == OS_OK) {
870 st->print("os_prio=%d ", os_prio);
871 }
872 st->print("tid=" INTPTR_FORMAT " ", this);
873 ext().print_on(st);
874 osthread()->print_on(st);
875 }
876 debug_only(if (WizardMode) print_owned_locks_on(st);)
877 }
879 // Thread::print_on_error() is called by fatal error handler. Don't use
880 // any lock or allocate memory.
881 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
882 if (is_VM_thread()) st->print("VMThread");
883 else if (is_Compiler_thread()) st->print("CompilerThread");
884 else if (is_Java_thread()) st->print("JavaThread");
885 else if (is_GC_task_thread()) st->print("GCTaskThread");
886 else if (is_Watcher_thread()) st->print("WatcherThread");
887 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
888 else st->print("Thread");
890 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
891 _stack_base - _stack_size, _stack_base);
893 if (osthread()) {
894 st->print(" [id=%d]", osthread()->thread_id());
895 }
896 }
898 #ifdef ASSERT
899 void Thread::print_owned_locks_on(outputStream* st) const {
900 Monitor *cur = _owned_locks;
901 if (cur == NULL) {
902 st->print(" (no locks) ");
903 } else {
904 st->print_cr(" Locks owned:");
905 while(cur) {
906 cur->print_on(st);
907 cur = cur->next();
908 }
909 }
910 }
912 static int ref_use_count = 0;
914 bool Thread::owns_locks_but_compiled_lock() const {
915 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
916 if (cur != Compile_lock) return true;
917 }
918 return false;
919 }
922 #endif
924 #ifndef PRODUCT
926 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
927 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
928 // no threads which allow_vm_block's are held
929 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
930 // Check if current thread is allowed to block at a safepoint
931 if (!(_allow_safepoint_count == 0))
932 fatal("Possible safepoint reached by thread that does not allow it");
933 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
934 fatal("LEAF method calling lock?");
935 }
937 #ifdef ASSERT
938 if (potential_vm_operation && is_Java_thread()
939 && !Universe::is_bootstrapping()) {
940 // Make sure we do not hold any locks that the VM thread also uses.
941 // This could potentially lead to deadlocks
942 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
943 // Threads_lock is special, since the safepoint synchronization will not start before this is
944 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
945 // since it is used to transfer control between JavaThreads and the VMThread
946 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
947 if ( (cur->allow_vm_block() &&
948 cur != Threads_lock &&
949 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
950 cur != VMOperationRequest_lock &&
951 cur != VMOperationQueue_lock) ||
952 cur->rank() == Mutex::special) {
953 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
954 }
955 }
956 }
958 if (GCALotAtAllSafepoints) {
959 // We could enter a safepoint here and thus have a gc
960 InterfaceSupport::check_gc_alot();
961 }
962 #endif
963 }
964 #endif
966 bool Thread::is_in_stack(address adr) const {
967 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
968 address end = os::current_stack_pointer();
969 // Allow non Java threads to call this without stack_base
970 if (_stack_base == NULL) return true;
971 if (stack_base() > adr && adr >= end) return true;
973 return false;
974 }
977 bool Thread::is_in_usable_stack(address adr) const {
978 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
979 size_t usable_stack_size = _stack_size - stack_guard_size;
981 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
982 }
985 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
986 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
987 // used for compilation in the future. If that change is made, the need for these methods
988 // should be revisited, and they should be removed if possible.
990 bool Thread::is_lock_owned(address adr) const {
991 return on_local_stack(adr);
992 }
994 bool Thread::set_as_starting_thread() {
995 // NOTE: this must be called inside the main thread.
996 return os::create_main_thread((JavaThread*)this);
997 }
999 static void initialize_class(Symbol* class_name, TRAPS) {
1000 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1001 InstanceKlass::cast(klass)->initialize(CHECK);
1002 }
1005 // Creates the initial ThreadGroup
1006 static Handle create_initial_thread_group(TRAPS) {
1007 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1008 instanceKlassHandle klass (THREAD, k);
1010 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1011 {
1012 JavaValue result(T_VOID);
1013 JavaCalls::call_special(&result,
1014 system_instance,
1015 klass,
1016 vmSymbols::object_initializer_name(),
1017 vmSymbols::void_method_signature(),
1018 CHECK_NH);
1019 }
1020 Universe::set_system_thread_group(system_instance());
1022 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1023 {
1024 JavaValue result(T_VOID);
1025 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1026 JavaCalls::call_special(&result,
1027 main_instance,
1028 klass,
1029 vmSymbols::object_initializer_name(),
1030 vmSymbols::threadgroup_string_void_signature(),
1031 system_instance,
1032 string,
1033 CHECK_NH);
1034 }
1035 return main_instance;
1036 }
1038 // Creates the initial Thread
1039 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1040 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1041 instanceKlassHandle klass (THREAD, k);
1042 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1044 java_lang_Thread::set_thread(thread_oop(), thread);
1045 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1046 thread->set_threadObj(thread_oop());
1048 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1050 JavaValue result(T_VOID);
1051 JavaCalls::call_special(&result, thread_oop,
1052 klass,
1053 vmSymbols::object_initializer_name(),
1054 vmSymbols::threadgroup_string_void_signature(),
1055 thread_group,
1056 string,
1057 CHECK_NULL);
1058 return thread_oop();
1059 }
1061 static void call_initializeSystemClass(TRAPS) {
1062 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1063 instanceKlassHandle klass (THREAD, k);
1065 JavaValue result(T_VOID);
1066 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1067 vmSymbols::void_method_signature(), CHECK);
1068 }
1070 char java_runtime_name[128] = "";
1071 char java_runtime_version[128] = "";
1073 // extract the JRE name from sun.misc.Version.java_runtime_name
1074 static const char* get_java_runtime_name(TRAPS) {
1075 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1076 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1077 fieldDescriptor fd;
1078 bool found = k != NULL &&
1079 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1080 vmSymbols::string_signature(), &fd);
1081 if (found) {
1082 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1083 if (name_oop == NULL)
1084 return NULL;
1085 const char* name = java_lang_String::as_utf8_string(name_oop,
1086 java_runtime_name,
1087 sizeof(java_runtime_name));
1088 return name;
1089 } else {
1090 return NULL;
1091 }
1092 }
1094 // extract the JRE version from sun.misc.Version.java_runtime_version
1095 static const char* get_java_runtime_version(TRAPS) {
1096 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1097 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1098 fieldDescriptor fd;
1099 bool found = k != NULL &&
1100 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1101 vmSymbols::string_signature(), &fd);
1102 if (found) {
1103 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1104 if (name_oop == NULL)
1105 return NULL;
1106 const char* name = java_lang_String::as_utf8_string(name_oop,
1107 java_runtime_version,
1108 sizeof(java_runtime_version));
1109 return name;
1110 } else {
1111 return NULL;
1112 }
1113 }
1115 // General purpose hook into Java code, run once when the VM is initialized.
1116 // The Java library method itself may be changed independently from the VM.
1117 static void call_postVMInitHook(TRAPS) {
1118 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1119 instanceKlassHandle klass (THREAD, k);
1120 if (klass.not_null()) {
1121 JavaValue result(T_VOID);
1122 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1123 vmSymbols::void_method_signature(),
1124 CHECK);
1125 }
1126 }
1128 static void reset_vm_info_property(TRAPS) {
1129 // the vm info string
1130 ResourceMark rm(THREAD);
1131 const char *vm_info = VM_Version::vm_info_string();
1133 // java.lang.System class
1134 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1135 instanceKlassHandle klass (THREAD, k);
1137 // setProperty arguments
1138 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1139 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1141 // return value
1142 JavaValue r(T_OBJECT);
1144 // public static String setProperty(String key, String value);
1145 JavaCalls::call_static(&r,
1146 klass,
1147 vmSymbols::setProperty_name(),
1148 vmSymbols::string_string_string_signature(),
1149 key_str,
1150 value_str,
1151 CHECK);
1152 }
1155 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1156 assert(thread_group.not_null(), "thread group should be specified");
1157 assert(threadObj() == NULL, "should only create Java thread object once");
1159 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1160 instanceKlassHandle klass (THREAD, k);
1161 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1163 java_lang_Thread::set_thread(thread_oop(), this);
1164 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1165 set_threadObj(thread_oop());
1167 JavaValue result(T_VOID);
1168 if (thread_name != NULL) {
1169 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1170 // Thread gets assigned specified name and null target
1171 JavaCalls::call_special(&result,
1172 thread_oop,
1173 klass,
1174 vmSymbols::object_initializer_name(),
1175 vmSymbols::threadgroup_string_void_signature(),
1176 thread_group, // Argument 1
1177 name, // Argument 2
1178 THREAD);
1179 } else {
1180 // Thread gets assigned name "Thread-nnn" and null target
1181 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1182 JavaCalls::call_special(&result,
1183 thread_oop,
1184 klass,
1185 vmSymbols::object_initializer_name(),
1186 vmSymbols::threadgroup_runnable_void_signature(),
1187 thread_group, // Argument 1
1188 Handle(), // Argument 2
1189 THREAD);
1190 }
1193 if (daemon) {
1194 java_lang_Thread::set_daemon(thread_oop());
1195 }
1197 if (HAS_PENDING_EXCEPTION) {
1198 return;
1199 }
1201 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1202 Handle threadObj(this, this->threadObj());
1204 JavaCalls::call_special(&result,
1205 thread_group,
1206 group,
1207 vmSymbols::add_method_name(),
1208 vmSymbols::thread_void_signature(),
1209 threadObj, // Arg 1
1210 THREAD);
1213 }
1215 // NamedThread -- non-JavaThread subclasses with multiple
1216 // uniquely named instances should derive from this.
1217 NamedThread::NamedThread() : Thread() {
1218 _name = NULL;
1219 _processed_thread = NULL;
1220 }
1222 NamedThread::~NamedThread() {
1223 JFR_ONLY(Jfr::on_thread_exit(this);)
1224 if (_name != NULL) {
1225 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1226 _name = NULL;
1227 }
1228 }
1230 void NamedThread::set_name(const char* format, ...) {
1231 guarantee(_name == NULL, "Only get to set name once.");
1232 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1233 guarantee(_name != NULL, "alloc failure");
1234 va_list ap;
1235 va_start(ap, format);
1236 jio_vsnprintf(_name, max_name_len, format, ap);
1237 va_end(ap);
1238 }
1240 // ======= WatcherThread ========
1242 // The watcher thread exists to simulate timer interrupts. It should
1243 // be replaced by an abstraction over whatever native support for
1244 // timer interrupts exists on the platform.
1246 WatcherThread* WatcherThread::_watcher_thread = NULL;
1247 bool WatcherThread::_startable = false;
1248 volatile bool WatcherThread::_should_terminate = false;
1250 WatcherThread::WatcherThread() : Thread() {
1251 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1252 if (os::create_thread(this, os::watcher_thread)) {
1253 _watcher_thread = this;
1255 // Set the watcher thread to the highest OS priority which should not be
1256 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1257 // is created. The only normal thread using this priority is the reference
1258 // handler thread, which runs for very short intervals only.
1259 // If the VMThread's priority is not lower than the WatcherThread profiling
1260 // will be inaccurate.
1261 os::set_priority(this, MaxPriority);
1262 if (!DisableStartThread) {
1263 os::start_thread(this);
1264 }
1265 }
1266 }
1268 int WatcherThread::sleep() const {
1269 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1271 // remaining will be zero if there are no tasks,
1272 // causing the WatcherThread to sleep until a task is
1273 // enrolled
1274 int remaining = PeriodicTask::time_to_wait();
1275 int time_slept = 0;
1277 // we expect this to timeout - we only ever get unparked when
1278 // we should terminate or when a new task has been enrolled
1279 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1281 jlong time_before_loop = os::javaTimeNanos();
1283 for (;;) {
1284 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1285 jlong now = os::javaTimeNanos();
1287 if (remaining == 0) {
1288 // if we didn't have any tasks we could have waited for a long time
1289 // consider the time_slept zero and reset time_before_loop
1290 time_slept = 0;
1291 time_before_loop = now;
1292 } else {
1293 // need to recalulate since we might have new tasks in _tasks
1294 time_slept = (int) ((now - time_before_loop) / 1000000);
1295 }
1297 // Change to task list or spurious wakeup of some kind
1298 if (timedout || _should_terminate) {
1299 break;
1300 }
1302 remaining = PeriodicTask::time_to_wait();
1303 if (remaining == 0) {
1304 // Last task was just disenrolled so loop around and wait until
1305 // another task gets enrolled
1306 continue;
1307 }
1309 remaining -= time_slept;
1310 if (remaining <= 0)
1311 break;
1312 }
1314 return time_slept;
1315 }
1317 void WatcherThread::run() {
1318 assert(this == watcher_thread(), "just checking");
1320 this->record_stack_base_and_size();
1321 this->initialize_thread_local_storage();
1322 this->set_native_thread_name(this->name());
1323 this->set_active_handles(JNIHandleBlock::allocate_block());
1324 while(!_should_terminate) {
1325 assert(watcher_thread() == Thread::current(), "thread consistency check");
1326 assert(watcher_thread() == this, "thread consistency check");
1328 // Calculate how long it'll be until the next PeriodicTask work
1329 // should be done, and sleep that amount of time.
1330 int time_waited = sleep();
1332 if (is_error_reported()) {
1333 // A fatal error has happened, the error handler(VMError::report_and_die)
1334 // should abort JVM after creating an error log file. However in some
1335 // rare cases, the error handler itself might deadlock. Here we try to
1336 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1337 //
1338 // This code is in WatcherThread because WatcherThread wakes up
1339 // periodically so the fatal error handler doesn't need to do anything;
1340 // also because the WatcherThread is less likely to crash than other
1341 // threads.
1343 for (;;) {
1344 if (!ShowMessageBoxOnError
1345 && (OnError == NULL || OnError[0] == '\0')
1346 && Arguments::abort_hook() == NULL) {
1347 os::sleep(this, 2 * 60 * 1000, false);
1348 fdStream err(defaultStream::output_fd());
1349 err.print_raw_cr("# [ timer expired, abort... ]");
1350 // skip atexit/vm_exit/vm_abort hooks
1351 os::die();
1352 }
1354 // Wake up 5 seconds later, the fatal handler may reset OnError or
1355 // ShowMessageBoxOnError when it is ready to abort.
1356 os::sleep(this, 5 * 1000, false);
1357 }
1358 }
1360 PeriodicTask::real_time_tick(time_waited);
1361 }
1363 // Signal that it is terminated
1364 {
1365 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1366 _watcher_thread = NULL;
1367 Terminator_lock->notify();
1368 }
1370 // Thread destructor usually does this..
1371 ThreadLocalStorage::set_thread(NULL);
1372 }
1374 void WatcherThread::start() {
1375 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1377 if (watcher_thread() == NULL && _startable) {
1378 _should_terminate = false;
1379 // Create the single instance of WatcherThread
1380 new WatcherThread();
1381 }
1382 }
1384 void WatcherThread::make_startable() {
1385 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1386 _startable = true;
1387 }
1389 void WatcherThread::stop() {
1390 {
1391 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1392 _should_terminate = true;
1393 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1395 WatcherThread* watcher = watcher_thread();
1396 if (watcher != NULL)
1397 watcher->unpark();
1398 }
1400 // it is ok to take late safepoints here, if needed
1401 MutexLocker mu(Terminator_lock);
1403 while(watcher_thread() != NULL) {
1404 // This wait should make safepoint checks, wait without a timeout,
1405 // and wait as a suspend-equivalent condition.
1406 //
1407 // Note: If the FlatProfiler is running, then this thread is waiting
1408 // for the WatcherThread to terminate and the WatcherThread, via the
1409 // FlatProfiler task, is waiting for the external suspend request on
1410 // this thread to complete. wait_for_ext_suspend_completion() will
1411 // eventually timeout, but that takes time. Making this wait a
1412 // suspend-equivalent condition solves that timeout problem.
1413 //
1414 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1415 Mutex::_as_suspend_equivalent_flag);
1416 }
1417 }
1419 void WatcherThread::unpark() {
1420 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1421 PeriodicTask_lock->notify();
1422 }
1424 void WatcherThread::print_on(outputStream* st) const {
1425 st->print("\"%s\" ", name());
1426 Thread::print_on(st);
1427 st->cr();
1428 }
1430 // ======= JavaThread ========
1432 // A JavaThread is a normal Java thread
1434 void JavaThread::initialize() {
1435 // Initialize fields
1437 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1438 set_claimed_par_id(UINT_MAX);
1440 set_saved_exception_pc(NULL);
1441 set_threadObj(NULL);
1442 _anchor.clear();
1443 set_entry_point(NULL);
1444 set_jni_functions(jni_functions());
1445 set_callee_target(NULL);
1446 set_vm_result(NULL);
1447 set_vm_result_2(NULL);
1448 set_vframe_array_head(NULL);
1449 set_vframe_array_last(NULL);
1450 set_deferred_locals(NULL);
1451 set_deopt_mark(NULL);
1452 set_deopt_nmethod(NULL);
1453 clear_must_deopt_id();
1454 set_monitor_chunks(NULL);
1455 set_next(NULL);
1456 set_thread_state(_thread_new);
1457 _terminated = _not_terminated;
1458 _privileged_stack_top = NULL;
1459 _array_for_gc = NULL;
1460 _suspend_equivalent = false;
1461 _in_deopt_handler = 0;
1462 _doing_unsafe_access = false;
1463 _stack_guard_state = stack_guard_unused;
1464 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1465 _exception_pc = 0;
1466 _exception_handler_pc = 0;
1467 _is_method_handle_return = 0;
1468 _jvmti_thread_state= NULL;
1469 _should_post_on_exceptions_flag = JNI_FALSE;
1470 _jvmti_get_loaded_classes_closure = NULL;
1471 _interp_only_mode = 0;
1472 _special_runtime_exit_condition = _no_async_condition;
1473 _pending_async_exception = NULL;
1474 _thread_stat = NULL;
1475 _thread_stat = new ThreadStatistics();
1476 _blocked_on_compilation = false;
1477 _jni_active_critical = 0;
1478 _pending_jni_exception_check_fn = NULL;
1479 _do_not_unlock_if_synchronized = false;
1480 _cached_monitor_info = NULL;
1481 _parker = Parker::Allocate(this) ;
1483 #ifndef PRODUCT
1484 _jmp_ring_index = 0;
1485 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1486 record_jump(NULL, NULL, NULL, 0);
1487 }
1488 #endif /* PRODUCT */
1490 set_thread_profiler(NULL);
1491 if (FlatProfiler::is_active()) {
1492 // This is where we would decide to either give each thread it's own profiler
1493 // or use one global one from FlatProfiler,
1494 // or up to some count of the number of profiled threads, etc.
1495 ThreadProfiler* pp = new ThreadProfiler();
1496 pp->engage();
1497 set_thread_profiler(pp);
1498 }
1500 // Setup safepoint state info for this thread
1501 ThreadSafepointState::create(this);
1503 debug_only(_java_call_counter = 0);
1505 // JVMTI PopFrame support
1506 _popframe_condition = popframe_inactive;
1507 _popframe_preserved_args = NULL;
1508 _popframe_preserved_args_size = 0;
1509 _frames_to_pop_failed_realloc = 0;
1511 pd_initialize();
1512 }
1514 #if INCLUDE_ALL_GCS
1515 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1516 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1517 #endif // INCLUDE_ALL_GCS
1519 JavaThread::JavaThread(bool is_attaching_via_jni) :
1520 Thread()
1521 #if INCLUDE_ALL_GCS
1522 , _satb_mark_queue(&_satb_mark_queue_set),
1523 _dirty_card_queue(&_dirty_card_queue_set)
1524 #endif // INCLUDE_ALL_GCS
1525 {
1526 initialize();
1527 if (is_attaching_via_jni) {
1528 _jni_attach_state = _attaching_via_jni;
1529 } else {
1530 _jni_attach_state = _not_attaching_via_jni;
1531 }
1532 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1533 }
1535 bool JavaThread::reguard_stack(address cur_sp) {
1536 if (_stack_guard_state != stack_guard_yellow_disabled) {
1537 return true; // Stack already guarded or guard pages not needed.
1538 }
1540 if (register_stack_overflow()) {
1541 // For those architectures which have separate register and
1542 // memory stacks, we must check the register stack to see if
1543 // it has overflowed.
1544 return false;
1545 }
1547 // Java code never executes within the yellow zone: the latter is only
1548 // there to provoke an exception during stack banging. If java code
1549 // is executing there, either StackShadowPages should be larger, or
1550 // some exception code in c1, c2 or the interpreter isn't unwinding
1551 // when it should.
1552 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1554 enable_stack_yellow_zone();
1555 return true;
1556 }
1558 bool JavaThread::reguard_stack(void) {
1559 return reguard_stack(os::current_stack_pointer());
1560 }
1563 void JavaThread::block_if_vm_exited() {
1564 if (_terminated == _vm_exited) {
1565 // _vm_exited is set at safepoint, and Threads_lock is never released
1566 // we will block here forever
1567 Threads_lock->lock_without_safepoint_check();
1568 ShouldNotReachHere();
1569 }
1570 }
1573 // Remove this ifdef when C1 is ported to the compiler interface.
1574 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1576 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1577 Thread()
1578 #if INCLUDE_ALL_GCS
1579 , _satb_mark_queue(&_satb_mark_queue_set),
1580 _dirty_card_queue(&_dirty_card_queue_set)
1581 #endif // INCLUDE_ALL_GCS
1582 {
1583 if (TraceThreadEvents) {
1584 tty->print_cr("creating thread %p", this);
1585 }
1586 initialize();
1587 _jni_attach_state = _not_attaching_via_jni;
1588 set_entry_point(entry_point);
1589 // Create the native thread itself.
1590 // %note runtime_23
1591 os::ThreadType thr_type = os::java_thread;
1592 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1593 os::java_thread;
1594 os::create_thread(this, thr_type, stack_sz);
1595 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1596 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1597 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1598 // the exception consists of creating the exception object & initializing it, initialization
1599 // will leave the VM via a JavaCall and then all locks must be unlocked).
1600 //
1601 // The thread is still suspended when we reach here. Thread must be explicit started
1602 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1603 // by calling Threads:add. The reason why this is not done here, is because the thread
1604 // object must be fully initialized (take a look at JVM_Start)
1605 }
1607 JavaThread::~JavaThread() {
1608 if (TraceThreadEvents) {
1609 tty->print_cr("terminate thread %p", this);
1610 }
1612 // JSR166 -- return the parker to the free list
1613 Parker::Release(_parker);
1614 _parker = NULL ;
1616 // Free any remaining previous UnrollBlock
1617 vframeArray* old_array = vframe_array_last();
1619 if (old_array != NULL) {
1620 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1621 old_array->set_unroll_block(NULL);
1622 delete old_info;
1623 delete old_array;
1624 }
1626 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1627 if (deferred != NULL) {
1628 // This can only happen if thread is destroyed before deoptimization occurs.
1629 assert(deferred->length() != 0, "empty array!");
1630 do {
1631 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1632 deferred->remove_at(0);
1633 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1634 delete dlv;
1635 } while (deferred->length() != 0);
1636 delete deferred;
1637 }
1639 // All Java related clean up happens in exit
1640 ThreadSafepointState::destroy(this);
1641 if (_thread_profiler != NULL) delete _thread_profiler;
1642 if (_thread_stat != NULL) delete _thread_stat;
1643 }
1646 // The first routine called by a new Java thread
1647 void JavaThread::run() {
1648 // initialize thread-local alloc buffer related fields
1649 this->initialize_tlab();
1651 // used to test validitity of stack trace backs
1652 this->record_base_of_stack_pointer();
1654 // Record real stack base and size.
1655 this->record_stack_base_and_size();
1657 // Initialize thread local storage; set before calling MutexLocker
1658 this->initialize_thread_local_storage();
1660 this->create_stack_guard_pages();
1662 this->cache_global_variables();
1664 // Thread is now sufficient initialized to be handled by the safepoint code as being
1665 // in the VM. Change thread state from _thread_new to _thread_in_vm
1666 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1668 assert(JavaThread::current() == this, "sanity check");
1669 assert(!Thread::current()->owns_locks(), "sanity check");
1671 DTRACE_THREAD_PROBE(start, this);
1673 // This operation might block. We call that after all safepoint checks for a new thread has
1674 // been completed.
1675 this->set_active_handles(JNIHandleBlock::allocate_block());
1677 if (JvmtiExport::should_post_thread_life()) {
1678 JvmtiExport::post_thread_start(this);
1679 }
1681 JFR_ONLY(Jfr::on_thread_start(this);)
1683 // We call another function to do the rest so we are sure that the stack addresses used
1684 // from there will be lower than the stack base just computed
1685 thread_main_inner();
1687 // Note, thread is no longer valid at this point!
1688 }
1691 void JavaThread::thread_main_inner() {
1692 assert(JavaThread::current() == this, "sanity check");
1693 assert(this->threadObj() != NULL, "just checking");
1695 // Execute thread entry point unless this thread has a pending exception
1696 // or has been stopped before starting.
1697 // Note: Due to JVM_StopThread we can have pending exceptions already!
1698 if (!this->has_pending_exception() &&
1699 !java_lang_Thread::is_stillborn(this->threadObj())) {
1700 {
1701 ResourceMark rm(this);
1702 this->set_native_thread_name(this->get_thread_name());
1703 }
1704 HandleMark hm(this);
1705 this->entry_point()(this, this);
1706 }
1708 DTRACE_THREAD_PROBE(stop, this);
1710 this->exit(false);
1711 delete this;
1712 }
1715 static void ensure_join(JavaThread* thread) {
1716 // We do not need to grap the Threads_lock, since we are operating on ourself.
1717 Handle threadObj(thread, thread->threadObj());
1718 assert(threadObj.not_null(), "java thread object must exist");
1719 ObjectLocker lock(threadObj, thread);
1720 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1721 thread->clear_pending_exception();
1722 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1723 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1724 // Clear the native thread instance - this makes isAlive return false and allows the join()
1725 // to complete once we've done the notify_all below
1726 java_lang_Thread::set_thread(threadObj(), NULL);
1727 lock.notify_all(thread);
1728 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1729 thread->clear_pending_exception();
1730 }
1733 // For any new cleanup additions, please check to see if they need to be applied to
1734 // cleanup_failed_attach_current_thread as well.
1735 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1736 assert(this == JavaThread::current(), "thread consistency check");
1738 HandleMark hm(this);
1739 Handle uncaught_exception(this, this->pending_exception());
1740 this->clear_pending_exception();
1741 Handle threadObj(this, this->threadObj());
1742 assert(threadObj.not_null(), "Java thread object should be created");
1744 if (get_thread_profiler() != NULL) {
1745 get_thread_profiler()->disengage();
1746 ResourceMark rm;
1747 get_thread_profiler()->print(get_thread_name());
1748 }
1751 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1752 {
1753 EXCEPTION_MARK;
1755 CLEAR_PENDING_EXCEPTION;
1756 }
1757 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1758 // has to be fixed by a runtime query method
1759 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1760 // JSR-166: change call from from ThreadGroup.uncaughtException to
1761 // java.lang.Thread.dispatchUncaughtException
1762 if (uncaught_exception.not_null()) {
1763 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1764 {
1765 EXCEPTION_MARK;
1766 // Check if the method Thread.dispatchUncaughtException() exists. If so
1767 // call it. Otherwise we have an older library without the JSR-166 changes,
1768 // so call ThreadGroup.uncaughtException()
1769 KlassHandle recvrKlass(THREAD, threadObj->klass());
1770 CallInfo callinfo;
1771 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1772 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1773 vmSymbols::dispatchUncaughtException_name(),
1774 vmSymbols::throwable_void_signature(),
1775 KlassHandle(), false, false, THREAD);
1776 CLEAR_PENDING_EXCEPTION;
1777 methodHandle method = callinfo.selected_method();
1778 if (method.not_null()) {
1779 JavaValue result(T_VOID);
1780 JavaCalls::call_virtual(&result,
1781 threadObj, thread_klass,
1782 vmSymbols::dispatchUncaughtException_name(),
1783 vmSymbols::throwable_void_signature(),
1784 uncaught_exception,
1785 THREAD);
1786 } else {
1787 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1788 JavaValue result(T_VOID);
1789 JavaCalls::call_virtual(&result,
1790 group, thread_group,
1791 vmSymbols::uncaughtException_name(),
1792 vmSymbols::thread_throwable_void_signature(),
1793 threadObj, // Arg 1
1794 uncaught_exception, // Arg 2
1795 THREAD);
1796 }
1797 if (HAS_PENDING_EXCEPTION) {
1798 ResourceMark rm(this);
1799 jio_fprintf(defaultStream::error_stream(),
1800 "\nException: %s thrown from the UncaughtExceptionHandler"
1801 " in thread \"%s\"\n",
1802 pending_exception()->klass()->external_name(),
1803 get_thread_name());
1804 CLEAR_PENDING_EXCEPTION;
1805 }
1806 }
1807 }
1808 JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
1810 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1811 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1812 // is deprecated anyhow.
1813 if (!is_Compiler_thread()) {
1814 int count = 3;
1815 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1816 EXCEPTION_MARK;
1817 JavaValue result(T_VOID);
1818 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1819 JavaCalls::call_virtual(&result,
1820 threadObj, thread_klass,
1821 vmSymbols::exit_method_name(),
1822 vmSymbols::void_method_signature(),
1823 THREAD);
1824 CLEAR_PENDING_EXCEPTION;
1825 }
1826 }
1827 // notify JVMTI
1828 if (JvmtiExport::should_post_thread_life()) {
1829 JvmtiExport::post_thread_end(this);
1830 }
1832 // We have notified the agents that we are exiting, before we go on,
1833 // we must check for a pending external suspend request and honor it
1834 // in order to not surprise the thread that made the suspend request.
1835 while (true) {
1836 {
1837 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1838 if (!is_external_suspend()) {
1839 set_terminated(_thread_exiting);
1840 ThreadService::current_thread_exiting(this);
1841 break;
1842 }
1843 // Implied else:
1844 // Things get a little tricky here. We have a pending external
1845 // suspend request, but we are holding the SR_lock so we
1846 // can't just self-suspend. So we temporarily drop the lock
1847 // and then self-suspend.
1848 }
1850 ThreadBlockInVM tbivm(this);
1851 java_suspend_self();
1853 // We're done with this suspend request, but we have to loop around
1854 // and check again. Eventually we will get SR_lock without a pending
1855 // external suspend request and will be able to mark ourselves as
1856 // exiting.
1857 }
1858 // no more external suspends are allowed at this point
1859 } else {
1860 // before_exit() has already posted JVMTI THREAD_END events
1861 }
1863 // Notify waiters on thread object. This has to be done after exit() is called
1864 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1865 // group should have the destroyed bit set before waiters are notified).
1866 ensure_join(this);
1867 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1869 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1870 // held by this thread must be released. A detach operation must only
1871 // get here if there are no Java frames on the stack. Therefore, any
1872 // owned monitors at this point MUST be JNI-acquired monitors which are
1873 // pre-inflated and in the monitor cache.
1874 //
1875 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1876 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1877 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1878 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1879 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1880 }
1882 // These things needs to be done while we are still a Java Thread. Make sure that thread
1883 // is in a consistent state, in case GC happens
1884 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1885 JFR_ONLY(Jfr::on_thread_exit(this);)
1887 if (active_handles() != NULL) {
1888 JNIHandleBlock* block = active_handles();
1889 set_active_handles(NULL);
1890 JNIHandleBlock::release_block(block);
1891 }
1893 if (free_handle_block() != NULL) {
1894 JNIHandleBlock* block = free_handle_block();
1895 set_free_handle_block(NULL);
1896 JNIHandleBlock::release_block(block);
1897 }
1899 // These have to be removed while this is still a valid thread.
1900 remove_stack_guard_pages();
1902 if (UseTLAB) {
1903 tlab().make_parsable(true); // retire TLAB
1904 }
1906 if (JvmtiEnv::environments_might_exist()) {
1907 JvmtiExport::cleanup_thread(this);
1908 }
1910 // We must flush any deferred card marks before removing a thread from
1911 // the list of active threads.
1912 Universe::heap()->flush_deferred_store_barrier(this);
1913 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1915 #if INCLUDE_ALL_GCS
1916 // We must flush the G1-related buffers before removing a thread
1917 // from the list of active threads. We must do this after any deferred
1918 // card marks have been flushed (above) so that any entries that are
1919 // added to the thread's dirty card queue as a result are not lost.
1920 if (UseG1GC) {
1921 flush_barrier_queues();
1922 }
1923 #endif // INCLUDE_ALL_GCS
1925 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1926 Threads::remove(this);
1927 }
1929 #if INCLUDE_ALL_GCS
1930 // Flush G1-related queues.
1931 void JavaThread::flush_barrier_queues() {
1932 satb_mark_queue().flush();
1933 dirty_card_queue().flush();
1934 }
1936 void JavaThread::initialize_queues() {
1937 assert(!SafepointSynchronize::is_at_safepoint(),
1938 "we should not be at a safepoint");
1940 ObjPtrQueue& satb_queue = satb_mark_queue();
1941 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1942 // The SATB queue should have been constructed with its active
1943 // field set to false.
1944 assert(!satb_queue.is_active(), "SATB queue should not be active");
1945 assert(satb_queue.is_empty(), "SATB queue should be empty");
1946 // If we are creating the thread during a marking cycle, we should
1947 // set the active field of the SATB queue to true.
1948 if (satb_queue_set.is_active()) {
1949 satb_queue.set_active(true);
1950 }
1952 DirtyCardQueue& dirty_queue = dirty_card_queue();
1953 // The dirty card queue should have been constructed with its
1954 // active field set to true.
1955 assert(dirty_queue.is_active(), "dirty card queue should be active");
1956 }
1957 #endif // INCLUDE_ALL_GCS
1959 void JavaThread::cleanup_failed_attach_current_thread() {
1960 if (get_thread_profiler() != NULL) {
1961 get_thread_profiler()->disengage();
1962 ResourceMark rm;
1963 get_thread_profiler()->print(get_thread_name());
1964 }
1966 if (active_handles() != NULL) {
1967 JNIHandleBlock* block = active_handles();
1968 set_active_handles(NULL);
1969 JNIHandleBlock::release_block(block);
1970 }
1972 if (free_handle_block() != NULL) {
1973 JNIHandleBlock* block = free_handle_block();
1974 set_free_handle_block(NULL);
1975 JNIHandleBlock::release_block(block);
1976 }
1978 // These have to be removed while this is still a valid thread.
1979 remove_stack_guard_pages();
1981 if (UseTLAB) {
1982 tlab().make_parsable(true); // retire TLAB, if any
1983 }
1985 #if INCLUDE_ALL_GCS
1986 if (UseG1GC) {
1987 flush_barrier_queues();
1988 }
1989 #endif // INCLUDE_ALL_GCS
1991 Threads::remove(this);
1992 delete this;
1993 }
1998 JavaThread* JavaThread::active() {
1999 Thread* thread = ThreadLocalStorage::thread();
2000 assert(thread != NULL, "just checking");
2001 if (thread->is_Java_thread()) {
2002 return (JavaThread*) thread;
2003 } else {
2004 assert(thread->is_VM_thread(), "this must be a vm thread");
2005 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2006 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2007 assert(ret->is_Java_thread(), "must be a Java thread");
2008 return ret;
2009 }
2010 }
2012 bool JavaThread::is_lock_owned(address adr) const {
2013 if (Thread::is_lock_owned(adr)) return true;
2015 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2016 if (chunk->contains(adr)) return true;
2017 }
2019 return false;
2020 }
2023 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2024 chunk->set_next(monitor_chunks());
2025 set_monitor_chunks(chunk);
2026 }
2028 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2029 guarantee(monitor_chunks() != NULL, "must be non empty");
2030 if (monitor_chunks() == chunk) {
2031 set_monitor_chunks(chunk->next());
2032 } else {
2033 MonitorChunk* prev = monitor_chunks();
2034 while (prev->next() != chunk) prev = prev->next();
2035 prev->set_next(chunk->next());
2036 }
2037 }
2039 // JVM support.
2041 // Note: this function shouldn't block if it's called in
2042 // _thread_in_native_trans state (such as from
2043 // check_special_condition_for_native_trans()).
2044 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2046 if (has_last_Java_frame() && has_async_condition()) {
2047 // If we are at a polling page safepoint (not a poll return)
2048 // then we must defer async exception because live registers
2049 // will be clobbered by the exception path. Poll return is
2050 // ok because the call we a returning from already collides
2051 // with exception handling registers and so there is no issue.
2052 // (The exception handling path kills call result registers but
2053 // this is ok since the exception kills the result anyway).
2055 if (is_at_poll_safepoint()) {
2056 // if the code we are returning to has deoptimized we must defer
2057 // the exception otherwise live registers get clobbered on the
2058 // exception path before deoptimization is able to retrieve them.
2059 //
2060 RegisterMap map(this, false);
2061 frame caller_fr = last_frame().sender(&map);
2062 assert(caller_fr.is_compiled_frame(), "what?");
2063 if (caller_fr.is_deoptimized_frame()) {
2064 if (TraceExceptions) {
2065 ResourceMark rm;
2066 tty->print_cr("deferred async exception at compiled safepoint");
2067 }
2068 return;
2069 }
2070 }
2071 }
2073 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2074 if (condition == _no_async_condition) {
2075 // Conditions have changed since has_special_runtime_exit_condition()
2076 // was called:
2077 // - if we were here only because of an external suspend request,
2078 // then that was taken care of above (or cancelled) so we are done
2079 // - if we were here because of another async request, then it has
2080 // been cleared between the has_special_runtime_exit_condition()
2081 // and now so again we are done
2082 return;
2083 }
2085 // Check for pending async. exception
2086 if (_pending_async_exception != NULL) {
2087 // Only overwrite an already pending exception, if it is not a threadDeath.
2088 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2090 // We cannot call Exceptions::_throw(...) here because we cannot block
2091 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2093 if (TraceExceptions) {
2094 ResourceMark rm;
2095 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2096 if (has_last_Java_frame() ) {
2097 frame f = last_frame();
2098 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2099 }
2100 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2101 }
2102 _pending_async_exception = NULL;
2103 clear_has_async_exception();
2104 }
2105 }
2107 if (check_unsafe_error &&
2108 condition == _async_unsafe_access_error && !has_pending_exception()) {
2109 condition = _no_async_condition; // done
2110 switch (thread_state()) {
2111 case _thread_in_vm:
2112 {
2113 JavaThread* THREAD = this;
2114 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2115 }
2116 case _thread_in_native:
2117 {
2118 ThreadInVMfromNative tiv(this);
2119 JavaThread* THREAD = this;
2120 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2121 }
2122 case _thread_in_Java:
2123 {
2124 ThreadInVMfromJava tiv(this);
2125 JavaThread* THREAD = this;
2126 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2127 }
2128 default:
2129 ShouldNotReachHere();
2130 }
2131 }
2133 assert(condition == _no_async_condition || has_pending_exception() ||
2134 (!check_unsafe_error && condition == _async_unsafe_access_error),
2135 "must have handled the async condition, if no exception");
2136 }
2138 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2139 //
2140 // Check for pending external suspend. Internal suspend requests do
2141 // not use handle_special_runtime_exit_condition().
2142 // If JNIEnv proxies are allowed, don't self-suspend if the target
2143 // thread is not the current thread. In older versions of jdbx, jdbx
2144 // threads could call into the VM with another thread's JNIEnv so we
2145 // can be here operating on behalf of a suspended thread (4432884).
2146 bool do_self_suspend = is_external_suspend_with_lock();
2147 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2148 //
2149 // Because thread is external suspended the safepoint code will count
2150 // thread as at a safepoint. This can be odd because we can be here
2151 // as _thread_in_Java which would normally transition to _thread_blocked
2152 // at a safepoint. We would like to mark the thread as _thread_blocked
2153 // before calling java_suspend_self like all other callers of it but
2154 // we must then observe proper safepoint protocol. (We can't leave
2155 // _thread_blocked with a safepoint in progress). However we can be
2156 // here as _thread_in_native_trans so we can't use a normal transition
2157 // constructor/destructor pair because they assert on that type of
2158 // transition. We could do something like:
2159 //
2160 // JavaThreadState state = thread_state();
2161 // set_thread_state(_thread_in_vm);
2162 // {
2163 // ThreadBlockInVM tbivm(this);
2164 // java_suspend_self()
2165 // }
2166 // set_thread_state(_thread_in_vm_trans);
2167 // if (safepoint) block;
2168 // set_thread_state(state);
2169 //
2170 // but that is pretty messy. Instead we just go with the way the
2171 // code has worked before and note that this is the only path to
2172 // java_suspend_self that doesn't put the thread in _thread_blocked
2173 // mode.
2175 frame_anchor()->make_walkable(this);
2176 java_suspend_self();
2178 // We might be here for reasons in addition to the self-suspend request
2179 // so check for other async requests.
2180 }
2182 if (check_asyncs) {
2183 check_and_handle_async_exceptions();
2184 }
2186 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2187 }
2189 void JavaThread::send_thread_stop(oop java_throwable) {
2190 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2191 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2192 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2194 // Do not throw asynchronous exceptions against the compiler thread
2195 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2196 if (is_Compiler_thread()) return;
2198 {
2199 // Actually throw the Throwable against the target Thread - however
2200 // only if there is no thread death exception installed already.
2201 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2202 // If the topmost frame is a runtime stub, then we are calling into
2203 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2204 // must deoptimize the caller before continuing, as the compiled exception handler table
2205 // may not be valid
2206 if (has_last_Java_frame()) {
2207 frame f = last_frame();
2208 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2209 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2210 RegisterMap reg_map(this, UseBiasedLocking);
2211 frame compiled_frame = f.sender(®_map);
2212 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2213 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2214 }
2215 }
2216 }
2218 // Set async. pending exception in thread.
2219 set_pending_async_exception(java_throwable);
2221 if (TraceExceptions) {
2222 ResourceMark rm;
2223 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2224 }
2225 // for AbortVMOnException flag
2226 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2227 }
2228 }
2231 // Interrupt thread so it will wake up from a potential wait()
2232 Thread::interrupt(this);
2233 }
2235 // External suspension mechanism.
2236 //
2237 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2238 // to any VM_locks and it is at a transition
2239 // Self-suspension will happen on the transition out of the vm.
2240 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2241 //
2242 // Guarantees on return:
2243 // + Target thread will not execute any new bytecode (that's why we need to
2244 // force a safepoint)
2245 // + Target thread will not enter any new monitors
2246 //
2247 void JavaThread::java_suspend() {
2248 { MutexLocker mu(Threads_lock);
2249 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2250 return;
2251 }
2252 }
2254 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2255 if (!is_external_suspend()) {
2256 // a racing resume has cancelled us; bail out now
2257 return;
2258 }
2260 // suspend is done
2261 uint32_t debug_bits = 0;
2262 // Warning: is_ext_suspend_completed() may temporarily drop the
2263 // SR_lock to allow the thread to reach a stable thread state if
2264 // it is currently in a transient thread state.
2265 if (is_ext_suspend_completed(false /* !called_by_wait */,
2266 SuspendRetryDelay, &debug_bits) ) {
2267 return;
2268 }
2269 }
2271 VM_ForceSafepoint vm_suspend;
2272 VMThread::execute(&vm_suspend);
2273 }
2275 // Part II of external suspension.
2276 // A JavaThread self suspends when it detects a pending external suspend
2277 // request. This is usually on transitions. It is also done in places
2278 // where continuing to the next transition would surprise the caller,
2279 // e.g., monitor entry.
2280 //
2281 // Returns the number of times that the thread self-suspended.
2282 //
2283 // Note: DO NOT call java_suspend_self() when you just want to block current
2284 // thread. java_suspend_self() is the second stage of cooperative
2285 // suspension for external suspend requests and should only be used
2286 // to complete an external suspend request.
2287 //
2288 int JavaThread::java_suspend_self() {
2289 int ret = 0;
2291 // we are in the process of exiting so don't suspend
2292 if (is_exiting()) {
2293 clear_external_suspend();
2294 return ret;
2295 }
2297 assert(_anchor.walkable() ||
2298 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2299 "must have walkable stack");
2301 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2303 assert(!this->is_ext_suspended(),
2304 "a thread trying to self-suspend should not already be suspended");
2306 if (this->is_suspend_equivalent()) {
2307 // If we are self-suspending as a result of the lifting of a
2308 // suspend equivalent condition, then the suspend_equivalent
2309 // flag is not cleared until we set the ext_suspended flag so
2310 // that wait_for_ext_suspend_completion() returns consistent
2311 // results.
2312 this->clear_suspend_equivalent();
2313 }
2315 // A racing resume may have cancelled us before we grabbed SR_lock
2316 // above. Or another external suspend request could be waiting for us
2317 // by the time we return from SR_lock()->wait(). The thread
2318 // that requested the suspension may already be trying to walk our
2319 // stack and if we return now, we can change the stack out from under
2320 // it. This would be a "bad thing (TM)" and cause the stack walker
2321 // to crash. We stay self-suspended until there are no more pending
2322 // external suspend requests.
2323 while (is_external_suspend()) {
2324 ret++;
2325 this->set_ext_suspended();
2327 // _ext_suspended flag is cleared by java_resume()
2328 while (is_ext_suspended()) {
2329 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2330 }
2331 }
2333 return ret;
2334 }
2336 #ifdef ASSERT
2337 // verify the JavaThread has not yet been published in the Threads::list, and
2338 // hence doesn't need protection from concurrent access at this stage
2339 void JavaThread::verify_not_published() {
2340 if (!Threads_lock->owned_by_self()) {
2341 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2342 assert( !Threads::includes(this),
2343 "java thread shouldn't have been published yet!");
2344 }
2345 else {
2346 assert( !Threads::includes(this),
2347 "java thread shouldn't have been published yet!");
2348 }
2349 }
2350 #endif
2352 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2353 // progress or when _suspend_flags is non-zero.
2354 // Current thread needs to self-suspend if there is a suspend request and/or
2355 // block if a safepoint is in progress.
2356 // Async exception ISN'T checked.
2357 // Note only the ThreadInVMfromNative transition can call this function
2358 // directly and when thread state is _thread_in_native_trans
2359 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2360 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2362 JavaThread *curJT = JavaThread::current();
2363 bool do_self_suspend = thread->is_external_suspend();
2365 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2367 // If JNIEnv proxies are allowed, don't self-suspend if the target
2368 // thread is not the current thread. In older versions of jdbx, jdbx
2369 // threads could call into the VM with another thread's JNIEnv so we
2370 // can be here operating on behalf of a suspended thread (4432884).
2371 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2372 JavaThreadState state = thread->thread_state();
2374 // We mark this thread_blocked state as a suspend-equivalent so
2375 // that a caller to is_ext_suspend_completed() won't be confused.
2376 // The suspend-equivalent state is cleared by java_suspend_self().
2377 thread->set_suspend_equivalent();
2379 // If the safepoint code sees the _thread_in_native_trans state, it will
2380 // wait until the thread changes to other thread state. There is no
2381 // guarantee on how soon we can obtain the SR_lock and complete the
2382 // self-suspend request. It would be a bad idea to let safepoint wait for
2383 // too long. Temporarily change the state to _thread_blocked to
2384 // let the VM thread know that this thread is ready for GC. The problem
2385 // of changing thread state is that safepoint could happen just after
2386 // java_suspend_self() returns after being resumed, and VM thread will
2387 // see the _thread_blocked state. We must check for safepoint
2388 // after restoring the state and make sure we won't leave while a safepoint
2389 // is in progress.
2390 thread->set_thread_state(_thread_blocked);
2391 thread->java_suspend_self();
2392 thread->set_thread_state(state);
2393 // Make sure new state is seen by VM thread
2394 if (os::is_MP()) {
2395 if (UseMembar) {
2396 // Force a fence between the write above and read below
2397 OrderAccess::fence();
2398 } else {
2399 // Must use this rather than serialization page in particular on Windows
2400 InterfaceSupport::serialize_memory(thread);
2401 }
2402 }
2403 }
2405 if (SafepointSynchronize::do_call_back()) {
2406 // If we are safepointing, then block the caller which may not be
2407 // the same as the target thread (see above).
2408 SafepointSynchronize::block(curJT);
2409 }
2411 if (thread->is_deopt_suspend()) {
2412 thread->clear_deopt_suspend();
2413 RegisterMap map(thread, false);
2414 frame f = thread->last_frame();
2415 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2416 f = f.sender(&map);
2417 }
2418 if (f.id() == thread->must_deopt_id()) {
2419 thread->clear_must_deopt_id();
2420 f.deoptimize(thread);
2421 } else {
2422 fatal("missed deoptimization!");
2423 }
2424 }
2426 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2427 }
2429 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2430 // progress or when _suspend_flags is non-zero.
2431 // Current thread needs to self-suspend if there is a suspend request and/or
2432 // block if a safepoint is in progress.
2433 // Also check for pending async exception (not including unsafe access error).
2434 // Note only the native==>VM/Java barriers can call this function and when
2435 // thread state is _thread_in_native_trans.
2436 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2437 check_safepoint_and_suspend_for_native_trans(thread);
2439 if (thread->has_async_exception()) {
2440 // We are in _thread_in_native_trans state, don't handle unsafe
2441 // access error since that may block.
2442 thread->check_and_handle_async_exceptions(false);
2443 }
2444 }
2446 // This is a variant of the normal
2447 // check_special_condition_for_native_trans with slightly different
2448 // semantics for use by critical native wrappers. It does all the
2449 // normal checks but also performs the transition back into
2450 // thread_in_Java state. This is required so that critical natives
2451 // can potentially block and perform a GC if they are the last thread
2452 // exiting the GC_locker.
2453 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2454 check_special_condition_for_native_trans(thread);
2456 // Finish the transition
2457 thread->set_thread_state(_thread_in_Java);
2459 if (thread->do_critical_native_unlock()) {
2460 ThreadInVMfromJavaNoAsyncException tiv(thread);
2461 GC_locker::unlock_critical(thread);
2462 thread->clear_critical_native_unlock();
2463 }
2464 }
2466 // We need to guarantee the Threads_lock here, since resumes are not
2467 // allowed during safepoint synchronization
2468 // Can only resume from an external suspension
2469 void JavaThread::java_resume() {
2470 assert_locked_or_safepoint(Threads_lock);
2472 // Sanity check: thread is gone, has started exiting or the thread
2473 // was not externally suspended.
2474 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2475 return;
2476 }
2478 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2480 clear_external_suspend();
2482 if (is_ext_suspended()) {
2483 clear_ext_suspended();
2484 SR_lock()->notify_all();
2485 }
2486 }
2488 void JavaThread::create_stack_guard_pages() {
2489 if (!os::uses_stack_guard_pages() ||
2490 _stack_guard_state != stack_guard_unused ||
2491 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2492 if (TraceThreadEvents) {
2493 tty->print_cr("Stack guard page creation for thread "
2494 UINTX_FORMAT " disabled", os::current_thread_id());
2495 }
2496 return;
2497 }
2498 address low_addr = stack_base() - stack_size();
2499 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2501 int allocate = os::allocate_stack_guard_pages();
2502 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2504 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2505 warning("Attempt to allocate stack guard pages failed.");
2506 return;
2507 }
2509 if (os::guard_memory((char *) low_addr, len)) {
2510 _stack_guard_state = stack_guard_enabled;
2511 } else {
2512 warning("Attempt to protect stack guard pages failed.");
2513 if (os::uncommit_memory((char *) low_addr, len)) {
2514 warning("Attempt to deallocate stack guard pages failed.");
2515 }
2516 }
2517 }
2519 void JavaThread::remove_stack_guard_pages() {
2520 assert(Thread::current() == this, "from different thread");
2521 if (_stack_guard_state == stack_guard_unused) return;
2522 address low_addr = stack_base() - stack_size();
2523 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2525 if (os::allocate_stack_guard_pages()) {
2526 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2527 _stack_guard_state = stack_guard_unused;
2528 } else {
2529 warning("Attempt to deallocate stack guard pages failed.");
2530 }
2531 } else {
2532 if (_stack_guard_state == stack_guard_unused) return;
2533 if (os::unguard_memory((char *) low_addr, len)) {
2534 _stack_guard_state = stack_guard_unused;
2535 } else {
2536 warning("Attempt to unprotect stack guard pages failed.");
2537 }
2538 }
2539 }
2541 void JavaThread::enable_stack_yellow_zone() {
2542 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2543 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2545 // The base notation is from the stacks point of view, growing downward.
2546 // We need to adjust it to work correctly with guard_memory()
2547 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2549 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2550 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2552 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2553 _stack_guard_state = stack_guard_enabled;
2554 } else {
2555 warning("Attempt to guard stack yellow zone failed.");
2556 }
2557 enable_register_stack_guard();
2558 }
2560 void JavaThread::disable_stack_yellow_zone() {
2561 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2562 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2564 // Simply return if called for a thread that does not use guard pages.
2565 if (_stack_guard_state == stack_guard_unused) return;
2567 // The base notation is from the stacks point of view, growing downward.
2568 // We need to adjust it to work correctly with guard_memory()
2569 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2571 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2572 _stack_guard_state = stack_guard_yellow_disabled;
2573 } else {
2574 warning("Attempt to unguard stack yellow zone failed.");
2575 }
2576 disable_register_stack_guard();
2577 }
2579 void JavaThread::enable_stack_red_zone() {
2580 // The base notation is from the stacks point of view, growing downward.
2581 // We need to adjust it to work correctly with guard_memory()
2582 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2583 address base = stack_red_zone_base() - stack_red_zone_size();
2585 guarantee(base < stack_base(),"Error calculating stack red zone");
2586 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2588 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2589 warning("Attempt to guard stack red zone failed.");
2590 }
2591 }
2593 void JavaThread::disable_stack_red_zone() {
2594 // The base notation is from the stacks point of view, growing downward.
2595 // We need to adjust it to work correctly with guard_memory()
2596 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2597 address base = stack_red_zone_base() - stack_red_zone_size();
2598 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2599 warning("Attempt to unguard stack red zone failed.");
2600 }
2601 }
2603 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2604 // ignore is there is no stack
2605 if (!has_last_Java_frame()) return;
2606 // traverse the stack frames. Starts from top frame.
2607 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2608 frame* fr = fst.current();
2609 f(fr, fst.register_map());
2610 }
2611 }
2614 #ifndef PRODUCT
2615 // Deoptimization
2616 // Function for testing deoptimization
2617 void JavaThread::deoptimize() {
2618 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2619 StackFrameStream fst(this, UseBiasedLocking);
2620 bool deopt = false; // Dump stack only if a deopt actually happens.
2621 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2622 // Iterate over all frames in the thread and deoptimize
2623 for(; !fst.is_done(); fst.next()) {
2624 if(fst.current()->can_be_deoptimized()) {
2626 if (only_at) {
2627 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2628 // consists of comma or carriage return separated numbers so
2629 // search for the current bci in that string.
2630 address pc = fst.current()->pc();
2631 nmethod* nm = (nmethod*) fst.current()->cb();
2632 ScopeDesc* sd = nm->scope_desc_at( pc);
2633 char buffer[8];
2634 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2635 size_t len = strlen(buffer);
2636 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2637 while (found != NULL) {
2638 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2639 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2640 // Check that the bci found is bracketed by terminators.
2641 break;
2642 }
2643 found = strstr(found + 1, buffer);
2644 }
2645 if (!found) {
2646 continue;
2647 }
2648 }
2650 if (DebugDeoptimization && !deopt) {
2651 deopt = true; // One-time only print before deopt
2652 tty->print_cr("[BEFORE Deoptimization]");
2653 trace_frames();
2654 trace_stack();
2655 }
2656 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2657 }
2658 }
2660 if (DebugDeoptimization && deopt) {
2661 tty->print_cr("[AFTER Deoptimization]");
2662 trace_frames();
2663 }
2664 }
2667 // Make zombies
2668 void JavaThread::make_zombies() {
2669 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2670 if (fst.current()->can_be_deoptimized()) {
2671 // it is a Java nmethod
2672 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2673 nm->make_not_entrant();
2674 }
2675 }
2676 }
2677 #endif // PRODUCT
2680 void JavaThread::deoptimized_wrt_marked_nmethods() {
2681 if (!has_last_Java_frame()) return;
2682 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2683 StackFrameStream fst(this, UseBiasedLocking);
2684 for(; !fst.is_done(); fst.next()) {
2685 if (fst.current()->should_be_deoptimized()) {
2686 if (LogCompilation && xtty != NULL) {
2687 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2688 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2689 this->name(), nm != NULL ? nm->compile_id() : -1);
2690 }
2692 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2693 }
2694 }
2695 }
2698 // GC support
2699 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2701 void JavaThread::gc_epilogue() {
2702 frames_do(frame_gc_epilogue);
2703 }
2706 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2708 void JavaThread::gc_prologue() {
2709 frames_do(frame_gc_prologue);
2710 }
2712 // If the caller is a NamedThread, then remember, in the current scope,
2713 // the given JavaThread in its _processed_thread field.
2714 class RememberProcessedThread: public StackObj {
2715 NamedThread* _cur_thr;
2716 public:
2717 RememberProcessedThread(JavaThread* jthr) {
2718 Thread* thread = Thread::current();
2719 if (thread->is_Named_thread()) {
2720 _cur_thr = (NamedThread *)thread;
2721 _cur_thr->set_processed_thread(jthr);
2722 } else {
2723 _cur_thr = NULL;
2724 }
2725 }
2727 ~RememberProcessedThread() {
2728 if (_cur_thr) {
2729 _cur_thr->set_processed_thread(NULL);
2730 }
2731 }
2732 };
2734 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2735 // Verify that the deferred card marks have been flushed.
2736 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2738 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2739 // since there may be more than one thread using each ThreadProfiler.
2741 // Traverse the GCHandles
2742 Thread::oops_do(f, cld_f, cf);
2744 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2745 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2747 if (has_last_Java_frame()) {
2748 // Record JavaThread to GC thread
2749 RememberProcessedThread rpt(this);
2751 // Traverse the privileged stack
2752 if (_privileged_stack_top != NULL) {
2753 _privileged_stack_top->oops_do(f);
2754 }
2756 // traverse the registered growable array
2757 if (_array_for_gc != NULL) {
2758 for (int index = 0; index < _array_for_gc->length(); index++) {
2759 f->do_oop(_array_for_gc->adr_at(index));
2760 }
2761 }
2763 // Traverse the monitor chunks
2764 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2765 chunk->oops_do(f);
2766 }
2768 // Traverse the execution stack
2769 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2770 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2771 }
2772 }
2774 // callee_target is never live across a gc point so NULL it here should
2775 // it still contain a methdOop.
2777 set_callee_target(NULL);
2779 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2780 // If we have deferred set_locals there might be oops waiting to be
2781 // written
2782 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2783 if (list != NULL) {
2784 for (int i = 0; i < list->length(); i++) {
2785 list->at(i)->oops_do(f);
2786 }
2787 }
2789 // Traverse instance variables at the end since the GC may be moving things
2790 // around using this function
2791 f->do_oop((oop*) &_threadObj);
2792 f->do_oop((oop*) &_vm_result);
2793 f->do_oop((oop*) &_exception_oop);
2794 f->do_oop((oop*) &_pending_async_exception);
2796 if (jvmti_thread_state() != NULL) {
2797 jvmti_thread_state()->oops_do(f);
2798 }
2799 }
2801 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2802 Thread::nmethods_do(cf); // (super method is a no-op)
2804 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2805 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2807 if (has_last_Java_frame()) {
2808 // Traverse the execution stack
2809 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2810 fst.current()->nmethods_do(cf);
2811 }
2812 }
2813 }
2815 void JavaThread::metadata_do(void f(Metadata*)) {
2816 Thread::metadata_do(f);
2817 if (has_last_Java_frame()) {
2818 // Traverse the execution stack to call f() on the methods in the stack
2819 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2820 fst.current()->metadata_do(f);
2821 }
2822 } else if (is_Compiler_thread()) {
2823 // need to walk ciMetadata in current compile tasks to keep alive.
2824 CompilerThread* ct = (CompilerThread*)this;
2825 if (ct->env() != NULL) {
2826 ct->env()->metadata_do(f);
2827 }
2828 }
2829 }
2831 // Printing
2832 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2833 switch (_thread_state) {
2834 case _thread_uninitialized: return "_thread_uninitialized";
2835 case _thread_new: return "_thread_new";
2836 case _thread_new_trans: return "_thread_new_trans";
2837 case _thread_in_native: return "_thread_in_native";
2838 case _thread_in_native_trans: return "_thread_in_native_trans";
2839 case _thread_in_vm: return "_thread_in_vm";
2840 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2841 case _thread_in_Java: return "_thread_in_Java";
2842 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2843 case _thread_blocked: return "_thread_blocked";
2844 case _thread_blocked_trans: return "_thread_blocked_trans";
2845 default: return "unknown thread state";
2846 }
2847 }
2849 #ifndef PRODUCT
2850 void JavaThread::print_thread_state_on(outputStream *st) const {
2851 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2852 };
2853 void JavaThread::print_thread_state() const {
2854 print_thread_state_on(tty);
2855 };
2856 #endif // PRODUCT
2858 // Called by Threads::print() for VM_PrintThreads operation
2859 void JavaThread::print_on(outputStream *st) const {
2860 st->print("\"%s\" ", get_thread_name());
2861 oop thread_oop = threadObj();
2862 if (thread_oop != NULL) {
2863 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2864 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2865 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2866 }
2867 Thread::print_on(st);
2868 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2869 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2870 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2871 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2872 }
2873 #ifndef PRODUCT
2874 print_thread_state_on(st);
2875 _safepoint_state->print_on(st);
2876 #endif // PRODUCT
2877 }
2879 // Called by fatal error handler. The difference between this and
2880 // JavaThread::print() is that we can't grab lock or allocate memory.
2881 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2882 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2883 oop thread_obj = threadObj();
2884 if (thread_obj != NULL) {
2885 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2886 }
2887 st->print(" [");
2888 st->print("%s", _get_thread_state_name(_thread_state));
2889 if (osthread()) {
2890 st->print(", id=%d", osthread()->thread_id());
2891 }
2892 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2893 _stack_base - _stack_size, _stack_base);
2894 st->print("]");
2895 return;
2896 }
2898 // Verification
2900 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2902 void JavaThread::verify() {
2903 // Verify oops in the thread.
2904 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2906 // Verify the stack frames.
2907 frames_do(frame_verify);
2908 }
2910 // CR 6300358 (sub-CR 2137150)
2911 // Most callers of this method assume that it can't return NULL but a
2912 // thread may not have a name whilst it is in the process of attaching to
2913 // the VM - see CR 6412693, and there are places where a JavaThread can be
2914 // seen prior to having it's threadObj set (eg JNI attaching threads and
2915 // if vm exit occurs during initialization). These cases can all be accounted
2916 // for such that this method never returns NULL.
2917 const char* JavaThread::get_thread_name() const {
2918 #ifdef ASSERT
2919 // early safepoints can hit while current thread does not yet have TLS
2920 if (!SafepointSynchronize::is_at_safepoint()) {
2921 Thread *cur = Thread::current();
2922 if (!(cur->is_Java_thread() && cur == this)) {
2923 // Current JavaThreads are allowed to get their own name without
2924 // the Threads_lock.
2925 assert_locked_or_safepoint(Threads_lock);
2926 }
2927 }
2928 #endif // ASSERT
2929 return get_thread_name_string();
2930 }
2932 // Returns a non-NULL representation of this thread's name, or a suitable
2933 // descriptive string if there is no set name
2934 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2935 const char* name_str;
2936 oop thread_obj = threadObj();
2937 if (thread_obj != NULL) {
2938 oop name = java_lang_Thread::name(thread_obj);
2939 if (name != NULL) {
2940 if (buf == NULL) {
2941 name_str = java_lang_String::as_utf8_string(name);
2942 }
2943 else {
2944 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2945 }
2946 }
2947 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2948 name_str = "<no-name - thread is attaching>";
2949 }
2950 else {
2951 name_str = Thread::name();
2952 }
2953 }
2954 else {
2955 name_str = Thread::name();
2956 }
2957 assert(name_str != NULL, "unexpected NULL thread name");
2958 return name_str;
2959 }
2962 const char* JavaThread::get_threadgroup_name() const {
2963 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2964 oop thread_obj = threadObj();
2965 if (thread_obj != NULL) {
2966 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2967 if (thread_group != NULL) {
2968 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2969 // ThreadGroup.name can be null
2970 if (name != NULL) {
2971 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2972 return str;
2973 }
2974 }
2975 }
2976 return NULL;
2977 }
2979 const char* JavaThread::get_parent_name() const {
2980 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2981 oop thread_obj = threadObj();
2982 if (thread_obj != NULL) {
2983 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2984 if (thread_group != NULL) {
2985 oop parent = java_lang_ThreadGroup::parent(thread_group);
2986 if (parent != NULL) {
2987 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2988 // ThreadGroup.name can be null
2989 if (name != NULL) {
2990 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2991 return str;
2992 }
2993 }
2994 }
2995 }
2996 return NULL;
2997 }
2999 ThreadPriority JavaThread::java_priority() const {
3000 oop thr_oop = threadObj();
3001 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3002 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3003 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3004 return priority;
3005 }
3007 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3009 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3010 // Link Java Thread object <-> C++ Thread
3012 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3013 // and put it into a new Handle. The Handle "thread_oop" can then
3014 // be used to pass the C++ thread object to other methods.
3016 // Set the Java level thread object (jthread) field of the
3017 // new thread (a JavaThread *) to C++ thread object using the
3018 // "thread_oop" handle.
3020 // Set the thread field (a JavaThread *) of the
3021 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3023 Handle thread_oop(Thread::current(),
3024 JNIHandles::resolve_non_null(jni_thread));
3025 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3026 "must be initialized");
3027 set_threadObj(thread_oop());
3028 java_lang_Thread::set_thread(thread_oop(), this);
3030 if (prio == NoPriority) {
3031 prio = java_lang_Thread::priority(thread_oop());
3032 assert(prio != NoPriority, "A valid priority should be present");
3033 }
3035 // Push the Java priority down to the native thread; needs Threads_lock
3036 Thread::set_priority(this, prio);
3038 prepare_ext();
3040 // Add the new thread to the Threads list and set it in motion.
3041 // We must have threads lock in order to call Threads::add.
3042 // It is crucial that we do not block before the thread is
3043 // added to the Threads list for if a GC happens, then the java_thread oop
3044 // will not be visited by GC.
3045 Threads::add(this);
3046 }
3048 oop JavaThread::current_park_blocker() {
3049 // Support for JSR-166 locks
3050 oop thread_oop = threadObj();
3051 if (thread_oop != NULL &&
3052 JDK_Version::current().supports_thread_park_blocker()) {
3053 return java_lang_Thread::park_blocker(thread_oop);
3054 }
3055 return NULL;
3056 }
3059 void JavaThread::print_stack_on(outputStream* st) {
3060 if (!has_last_Java_frame()) return;
3061 ResourceMark rm;
3062 HandleMark hm;
3064 RegisterMap reg_map(this);
3065 vframe* start_vf = last_java_vframe(®_map);
3066 int count = 0;
3067 for (vframe* f = start_vf; f; f = f->sender() ) {
3068 if (f->is_java_frame()) {
3069 javaVFrame* jvf = javaVFrame::cast(f);
3070 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3072 // Print out lock information
3073 if (JavaMonitorsInStackTrace) {
3074 jvf->print_lock_info_on(st, count);
3075 }
3076 } else {
3077 // Ignore non-Java frames
3078 }
3080 // Bail-out case for too deep stacks
3081 count++;
3082 if (MaxJavaStackTraceDepth == count) return;
3083 }
3084 }
3087 // JVMTI PopFrame support
3088 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3089 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3090 if (in_bytes(size_in_bytes) != 0) {
3091 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3092 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3093 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3094 }
3095 }
3097 void* JavaThread::popframe_preserved_args() {
3098 return _popframe_preserved_args;
3099 }
3101 ByteSize JavaThread::popframe_preserved_args_size() {
3102 return in_ByteSize(_popframe_preserved_args_size);
3103 }
3105 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3106 int sz = in_bytes(popframe_preserved_args_size());
3107 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3108 return in_WordSize(sz / wordSize);
3109 }
3111 void JavaThread::popframe_free_preserved_args() {
3112 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3113 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3114 _popframe_preserved_args = NULL;
3115 _popframe_preserved_args_size = 0;
3116 }
3118 #ifndef PRODUCT
3120 void JavaThread::trace_frames() {
3121 tty->print_cr("[Describe stack]");
3122 int frame_no = 1;
3123 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3124 tty->print(" %d. ", frame_no++);
3125 fst.current()->print_value_on(tty,this);
3126 tty->cr();
3127 }
3128 }
3130 class PrintAndVerifyOopClosure: public OopClosure {
3131 protected:
3132 template <class T> inline void do_oop_work(T* p) {
3133 oop obj = oopDesc::load_decode_heap_oop(p);
3134 if (obj == NULL) return;
3135 tty->print(INTPTR_FORMAT ": ", p);
3136 if (obj->is_oop_or_null()) {
3137 if (obj->is_objArray()) {
3138 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3139 } else {
3140 obj->print();
3141 }
3142 } else {
3143 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3144 }
3145 tty->cr();
3146 }
3147 public:
3148 virtual void do_oop(oop* p) { do_oop_work(p); }
3149 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3150 };
3153 static void oops_print(frame* f, const RegisterMap *map) {
3154 PrintAndVerifyOopClosure print;
3155 f->print_value();
3156 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3157 }
3159 // Print our all the locations that contain oops and whether they are
3160 // valid or not. This useful when trying to find the oldest frame
3161 // where an oop has gone bad since the frame walk is from youngest to
3162 // oldest.
3163 void JavaThread::trace_oops() {
3164 tty->print_cr("[Trace oops]");
3165 frames_do(oops_print);
3166 }
3169 #ifdef ASSERT
3170 // Print or validate the layout of stack frames
3171 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3172 ResourceMark rm;
3173 PRESERVE_EXCEPTION_MARK;
3174 FrameValues values;
3175 int frame_no = 0;
3176 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3177 fst.current()->describe(values, ++frame_no);
3178 if (depth == frame_no) break;
3179 }
3180 if (validate_only) {
3181 values.validate();
3182 } else {
3183 tty->print_cr("[Describe stack layout]");
3184 values.print(this);
3185 }
3186 }
3187 #endif
3189 void JavaThread::trace_stack_from(vframe* start_vf) {
3190 ResourceMark rm;
3191 int vframe_no = 1;
3192 for (vframe* f = start_vf; f; f = f->sender() ) {
3193 if (f->is_java_frame()) {
3194 javaVFrame::cast(f)->print_activation(vframe_no++);
3195 } else {
3196 f->print();
3197 }
3198 if (vframe_no > StackPrintLimit) {
3199 tty->print_cr("...<more frames>...");
3200 return;
3201 }
3202 }
3203 }
3206 void JavaThread::trace_stack() {
3207 if (!has_last_Java_frame()) return;
3208 ResourceMark rm;
3209 HandleMark hm;
3210 RegisterMap reg_map(this);
3211 trace_stack_from(last_java_vframe(®_map));
3212 }
3215 #endif // PRODUCT
3218 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3219 assert(reg_map != NULL, "a map must be given");
3220 frame f = last_frame();
3221 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3222 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3223 }
3224 return NULL;
3225 }
3228 Klass* JavaThread::security_get_caller_class(int depth) {
3229 vframeStream vfst(this);
3230 vfst.security_get_caller_frame(depth);
3231 if (!vfst.at_end()) {
3232 return vfst.method()->method_holder();
3233 }
3234 return NULL;
3235 }
3237 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3238 assert(thread->is_Compiler_thread(), "must be compiler thread");
3239 CompileBroker::compiler_thread_loop();
3240 }
3242 // Create a CompilerThread
3243 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3244 : JavaThread(&compiler_thread_entry) {
3245 _env = NULL;
3246 _log = NULL;
3247 _task = NULL;
3248 _queue = queue;
3249 _counters = counters;
3250 _buffer_blob = NULL;
3251 _scanned_nmethod = NULL;
3252 _compiler = NULL;
3254 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3255 resource_area()->bias_to(mtCompiler);
3257 #ifndef PRODUCT
3258 _ideal_graph_printer = NULL;
3259 #endif
3260 }
3262 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3263 JavaThread::oops_do(f, cld_f, cf);
3264 if (_scanned_nmethod != NULL && cf != NULL) {
3265 // Safepoints can occur when the sweeper is scanning an nmethod so
3266 // process it here to make sure it isn't unloaded in the middle of
3267 // a scan.
3268 cf->do_code_blob(_scanned_nmethod);
3269 }
3270 }
3273 // ======= Threads ========
3275 // The Threads class links together all active threads, and provides
3276 // operations over all threads. It is protected by its own Mutex
3277 // lock, which is also used in other contexts to protect thread
3278 // operations from having the thread being operated on from exiting
3279 // and going away unexpectedly (e.g., safepoint synchronization)
3281 JavaThread* Threads::_thread_list = NULL;
3282 int Threads::_number_of_threads = 0;
3283 int Threads::_number_of_non_daemon_threads = 0;
3284 int Threads::_return_code = 0;
3285 size_t JavaThread::_stack_size_at_create = 0;
3286 #ifdef ASSERT
3287 bool Threads::_vm_complete = false;
3288 #endif
3290 // All JavaThreads
3291 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3293 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3294 void Threads::threads_do(ThreadClosure* tc) {
3295 assert_locked_or_safepoint(Threads_lock);
3296 // ALL_JAVA_THREADS iterates through all JavaThreads
3297 ALL_JAVA_THREADS(p) {
3298 tc->do_thread(p);
3299 }
3300 // Someday we could have a table or list of all non-JavaThreads.
3301 // For now, just manually iterate through them.
3302 tc->do_thread(VMThread::vm_thread());
3303 Universe::heap()->gc_threads_do(tc);
3304 WatcherThread *wt = WatcherThread::watcher_thread();
3305 // Strictly speaking, the following NULL check isn't sufficient to make sure
3306 // the data for WatcherThread is still valid upon being examined. However,
3307 // considering that WatchThread terminates when the VM is on the way to
3308 // exit at safepoint, the chance of the above is extremely small. The right
3309 // way to prevent termination of WatcherThread would be to acquire
3310 // Terminator_lock, but we can't do that without violating the lock rank
3311 // checking in some cases.
3312 if (wt != NULL)
3313 tc->do_thread(wt);
3315 #if INCLUDE_JFR
3316 Thread* sampler_thread = Jfr::sampler_thread();
3317 if (sampler_thread != NULL) {
3318 tc->do_thread(sampler_thread);
3319 }
3321 #endif
3323 // If CompilerThreads ever become non-JavaThreads, add them here
3324 }
3326 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3328 extern void JDK_Version_init();
3330 // Preinitialize version info.
3331 VM_Version::early_initialize();
3333 // Check version
3334 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3336 // Initialize the output stream module
3337 ostream_init();
3339 // Process java launcher properties.
3340 Arguments::process_sun_java_launcher_properties(args);
3342 // Initialize the os module before using TLS
3343 os::init();
3345 // Initialize system properties.
3346 Arguments::init_system_properties();
3348 // So that JDK version can be used as a discrimintor when parsing arguments
3349 JDK_Version_init();
3351 // Update/Initialize System properties after JDK version number is known
3352 Arguments::init_version_specific_system_properties();
3354 // Parse arguments
3355 // Note: this internally calls os::init_container_support()
3356 jint parse_result = Arguments::parse(args);
3357 if (parse_result != JNI_OK) return parse_result;
3359 os::init_before_ergo();
3361 jint ergo_result = Arguments::apply_ergo();
3362 if (ergo_result != JNI_OK) return ergo_result;
3364 if (PauseAtStartup) {
3365 os::pause();
3366 }
3368 #ifndef USDT2
3369 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3370 #else /* USDT2 */
3371 HOTSPOT_VM_INIT_BEGIN();
3372 #endif /* USDT2 */
3374 // Record VM creation timing statistics
3375 TraceVmCreationTime create_vm_timer;
3376 create_vm_timer.start();
3378 // Timing (must come after argument parsing)
3379 TraceTime timer("Create VM", TraceStartupTime);
3381 // Initialize the os module after parsing the args
3382 jint os_init_2_result = os::init_2();
3383 if (os_init_2_result != JNI_OK) return os_init_2_result;
3385 jint adjust_after_os_result = Arguments::adjust_after_os();
3386 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3388 // intialize TLS
3389 ThreadLocalStorage::init();
3391 // Initialize output stream logging
3392 ostream_init_log();
3394 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3395 // Must be before create_vm_init_agents()
3396 if (Arguments::init_libraries_at_startup()) {
3397 convert_vm_init_libraries_to_agents();
3398 }
3400 // Launch -agentlib/-agentpath and converted -Xrun agents
3401 if (Arguments::init_agents_at_startup()) {
3402 create_vm_init_agents();
3403 }
3405 // Initialize Threads state
3406 _thread_list = NULL;
3407 _number_of_threads = 0;
3408 _number_of_non_daemon_threads = 0;
3410 // Initialize global data structures and create system classes in heap
3411 vm_init_globals();
3413 // Attach the main thread to this os thread
3414 JavaThread* main_thread = new JavaThread();
3415 main_thread->set_thread_state(_thread_in_vm);
3416 // must do this before set_active_handles and initialize_thread_local_storage
3417 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3418 // change the stack size recorded here to one based on the java thread
3419 // stacksize. This adjusted size is what is used to figure the placement
3420 // of the guard pages.
3421 main_thread->record_stack_base_and_size();
3422 main_thread->initialize_thread_local_storage();
3424 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3426 if (!main_thread->set_as_starting_thread()) {
3427 vm_shutdown_during_initialization(
3428 "Failed necessary internal allocation. Out of swap space");
3429 delete main_thread;
3430 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3431 return JNI_ENOMEM;
3432 }
3434 // Enable guard page *after* os::create_main_thread(), otherwise it would
3435 // crash Linux VM, see notes in os_linux.cpp.
3436 main_thread->create_stack_guard_pages();
3438 // Initialize Java-Level synchronization subsystem
3439 ObjectMonitor::Initialize() ;
3441 // Initialize global modules
3442 jint status = init_globals();
3443 if (status != JNI_OK) {
3444 delete main_thread;
3445 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3446 return status;
3447 }
3449 JFR_ONLY(Jfr::on_create_vm_1();)
3451 #if defined MIPS && !defined ZERO
3452 /* 2013/11/5 Jin: To be accessed in NativeGeneralJump::patch_verified_entry() */
3453 main_thread->set_handle_wrong_method_stub(SharedRuntime::get_handle_wrong_method_stub());
3454 #endif
3456 // Should be done after the heap is fully created
3457 main_thread->cache_global_variables();
3459 HandleMark hm;
3461 { MutexLocker mu(Threads_lock);
3462 Threads::add(main_thread);
3463 }
3465 // Any JVMTI raw monitors entered in onload will transition into
3466 // real raw monitor. VM is setup enough here for raw monitor enter.
3467 JvmtiExport::transition_pending_onload_raw_monitors();
3469 // Create the VMThread
3470 { TraceTime timer("Start VMThread", TraceStartupTime);
3471 VMThread::create();
3472 Thread* vmthread = VMThread::vm_thread();
3474 if (!os::create_thread(vmthread, os::vm_thread))
3475 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3477 // Wait for the VM thread to become ready, and VMThread::run to initialize
3478 // Monitors can have spurious returns, must always check another state flag
3479 {
3480 MutexLocker ml(Notify_lock);
3481 os::start_thread(vmthread);
3482 while (vmthread->active_handles() == NULL) {
3483 Notify_lock->wait();
3484 }
3485 }
3486 }
3488 assert (Universe::is_fully_initialized(), "not initialized");
3489 if (VerifyDuringStartup) {
3490 // Make sure we're starting with a clean slate.
3491 VM_Verify verify_op;
3492 VMThread::execute(&verify_op);
3493 }
3495 EXCEPTION_MARK;
3497 // At this point, the Universe is initialized, but we have not executed
3498 // any byte code. Now is a good time (the only time) to dump out the
3499 // internal state of the JVM for sharing.
3500 if (DumpSharedSpaces) {
3501 MetaspaceShared::preload_and_dump(CHECK_0);
3502 ShouldNotReachHere();
3503 }
3505 #if !INCLUDE_JFR
3506 // if JFR is not enabled at the build time keep the original JvmtiExport location
3508 // Always call even when there are not JVMTI environments yet, since environments
3509 // may be attached late and JVMTI must track phases of VM execution
3510 JvmtiExport::enter_start_phase();
3512 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3513 JvmtiExport::post_vm_start();
3514 #endif
3516 {
3517 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3519 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3520 create_vm_init_libraries();
3521 }
3523 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3525 // Initialize java_lang.System (needed before creating the thread)
3526 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3527 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3528 Handle thread_group = create_initial_thread_group(CHECK_0);
3529 Universe::set_main_thread_group(thread_group());
3530 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3531 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3532 main_thread->set_threadObj(thread_object);
3533 // Set thread status to running since main thread has
3534 // been started and running.
3535 java_lang_Thread::set_thread_status(thread_object,
3536 java_lang_Thread::RUNNABLE);
3538 // The VM creates & returns objects of this class. Make sure it's initialized.
3539 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3541 // The VM preresolves methods to these classes. Make sure that they get initialized
3542 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3543 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3544 call_initializeSystemClass(CHECK_0);
3546 // get the Java runtime name after java.lang.System is initialized
3547 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3548 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3550 // an instance of OutOfMemory exception has been allocated earlier
3551 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3552 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3553 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3554 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3555 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3556 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3557 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3558 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3559 }
3561 JFR_ONLY(
3562 Jfr::on_create_vm_2();
3564 // if JFR is enabled at build time the JVMTI needs to be handled only after on_create_vm_2() call
3566 // Always call even when there are not JVMTI environments yet, since environments
3567 // may be attached late and JVMTI must track phases of VM execution
3568 JvmtiExport::enter_start_phase();
3570 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3571 JvmtiExport::post_vm_start();
3572 )
3574 // See : bugid 4211085.
3575 // Background : the static initializer of java.lang.Compiler tries to read
3576 // property"java.compiler" and read & write property "java.vm.info".
3577 // When a security manager is installed through the command line
3578 // option "-Djava.security.manager", the above properties are not
3579 // readable and the static initializer for java.lang.Compiler fails
3580 // resulting in a NoClassDefFoundError. This can happen in any
3581 // user code which calls methods in java.lang.Compiler.
3582 // Hack : the hack is to pre-load and initialize this class, so that only
3583 // system domains are on the stack when the properties are read.
3584 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3585 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3586 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3587 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3588 // Once that is done, we should remove this hack.
3589 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3591 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3592 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3593 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3594 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3595 // This should also be taken out as soon as 4211383 gets fixed.
3596 reset_vm_info_property(CHECK_0);
3598 quicken_jni_functions();
3600 // Set flag that basic initialization has completed. Used by exceptions and various
3601 // debug stuff, that does not work until all basic classes have been initialized.
3602 set_init_completed();
3604 Metaspace::post_initialize();
3606 #ifndef USDT2
3607 HS_DTRACE_PROBE(hotspot, vm__init__end);
3608 #else /* USDT2 */
3609 HOTSPOT_VM_INIT_END();
3610 #endif /* USDT2 */
3612 // record VM initialization completion time
3613 #if INCLUDE_MANAGEMENT
3614 Management::record_vm_init_completed();
3615 #endif // INCLUDE_MANAGEMENT
3617 // Compute system loader. Note that this has to occur after set_init_completed, since
3618 // valid exceptions may be thrown in the process.
3619 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3620 // set_init_completed has just been called, causing exceptions not to be shortcut
3621 // anymore. We call vm_exit_during_initialization directly instead.
3622 SystemDictionary::compute_java_system_loader(THREAD);
3623 if (HAS_PENDING_EXCEPTION) {
3624 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3625 }
3627 #if INCLUDE_ALL_GCS
3628 // Support for ConcurrentMarkSweep. This should be cleaned up
3629 // and better encapsulated. The ugly nested if test would go away
3630 // once things are properly refactored. XXX YSR
3631 if (UseConcMarkSweepGC || UseG1GC) {
3632 if (UseConcMarkSweepGC) {
3633 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3634 } else {
3635 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3636 }
3637 if (HAS_PENDING_EXCEPTION) {
3638 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3639 }
3640 }
3641 #endif // INCLUDE_ALL_GCS
3643 // Always call even when there are not JVMTI environments yet, since environments
3644 // may be attached late and JVMTI must track phases of VM execution
3645 JvmtiExport::enter_live_phase();
3647 // Signal Dispatcher needs to be started before VMInit event is posted
3648 os::signal_init();
3650 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3651 if (!DisableAttachMechanism) {
3652 AttachListener::vm_start();
3653 if (StartAttachListener || AttachListener::init_at_startup()) {
3654 AttachListener::init();
3655 }
3656 }
3658 // Launch -Xrun agents
3659 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3660 // back-end can launch with -Xdebug -Xrunjdwp.
3661 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3662 create_vm_init_libraries();
3663 }
3665 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3666 JvmtiExport::post_vm_initialized();
3668 JFR_ONLY(Jfr::on_create_vm_3();)
3670 if (CleanChunkPoolAsync) {
3671 Chunk::start_chunk_pool_cleaner_task();
3672 }
3674 // initialize compiler(s)
3675 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3676 CompileBroker::compilation_init();
3677 #endif
3679 if (EnableInvokeDynamic) {
3680 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3681 // It is done after compilers are initialized, because otherwise compilations of
3682 // signature polymorphic MH intrinsics can be missed
3683 // (see SystemDictionary::find_method_handle_intrinsic).
3684 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3685 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3686 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3687 }
3689 #if INCLUDE_MANAGEMENT
3690 Management::initialize(THREAD);
3691 #endif // INCLUDE_MANAGEMENT
3693 if (HAS_PENDING_EXCEPTION) {
3694 // management agent fails to start possibly due to
3695 // configuration problem and is responsible for printing
3696 // stack trace if appropriate. Simply exit VM.
3697 vm_exit(1);
3698 }
3700 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3701 if (MemProfiling) MemProfiler::engage();
3702 StatSampler::engage();
3703 if (CheckJNICalls) JniPeriodicChecker::engage();
3705 BiasedLocking::init();
3707 #if INCLUDE_RTM_OPT
3708 RTMLockingCounters::init();
3709 #endif
3711 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3712 call_postVMInitHook(THREAD);
3713 // The Java side of PostVMInitHook.run must deal with all
3714 // exceptions and provide means of diagnosis.
3715 if (HAS_PENDING_EXCEPTION) {
3716 CLEAR_PENDING_EXCEPTION;
3717 }
3718 }
3720 {
3721 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3722 // Make sure the watcher thread can be started by WatcherThread::start()
3723 // or by dynamic enrollment.
3724 WatcherThread::make_startable();
3725 // Start up the WatcherThread if there are any periodic tasks
3726 // NOTE: All PeriodicTasks should be registered by now. If they
3727 // aren't, late joiners might appear to start slowly (we might
3728 // take a while to process their first tick).
3729 if (PeriodicTask::num_tasks() > 0) {
3730 WatcherThread::start();
3731 }
3732 }
3734 create_vm_timer.end();
3735 #ifdef ASSERT
3736 _vm_complete = true;
3737 #endif
3738 return JNI_OK;
3739 }
3741 // type for the Agent_OnLoad and JVM_OnLoad entry points
3742 extern "C" {
3743 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3744 }
3745 // Find a command line agent library and return its entry point for
3746 // -agentlib: -agentpath: -Xrun
3747 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3748 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3749 OnLoadEntry_t on_load_entry = NULL;
3750 void *library = NULL;
3752 if (!agent->valid()) {
3753 char buffer[JVM_MAXPATHLEN];
3754 char ebuf[1024];
3755 const char *name = agent->name();
3756 const char *msg = "Could not find agent library ";
3758 // First check to see if agent is statically linked into executable
3759 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3760 library = agent->os_lib();
3761 } else if (agent->is_absolute_path()) {
3762 library = os::dll_load(name, ebuf, sizeof ebuf);
3763 if (library == NULL) {
3764 const char *sub_msg = " in absolute path, with error: ";
3765 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3766 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3767 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3768 // If we can't find the agent, exit.
3769 vm_exit_during_initialization(buf, NULL);
3770 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3771 }
3772 } else {
3773 // Try to load the agent from the standard dll directory
3774 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3775 name)) {
3776 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3777 }
3778 if (library == NULL) { // Try the local directory
3779 char ns[1] = {0};
3780 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3781 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3782 }
3783 if (library == NULL) {
3784 const char *sub_msg = " on the library path, with error: ";
3785 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3786 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3787 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3788 // If we can't find the agent, exit.
3789 vm_exit_during_initialization(buf, NULL);
3790 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3791 }
3792 }
3793 }
3794 agent->set_os_lib(library);
3795 agent->set_valid();
3796 }
3798 // Find the OnLoad function.
3799 on_load_entry =
3800 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3801 false,
3802 on_load_symbols,
3803 num_symbol_entries));
3804 return on_load_entry;
3805 }
3807 // Find the JVM_OnLoad entry point
3808 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3809 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3810 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3811 }
3813 // Find the Agent_OnLoad entry point
3814 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3815 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3816 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3817 }
3819 // For backwards compatibility with -Xrun
3820 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3821 // treated like -agentpath:
3822 // Must be called before agent libraries are created
3823 void Threads::convert_vm_init_libraries_to_agents() {
3824 AgentLibrary* agent;
3825 AgentLibrary* next;
3827 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3828 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3829 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3831 // If there is an JVM_OnLoad function it will get called later,
3832 // otherwise see if there is an Agent_OnLoad
3833 if (on_load_entry == NULL) {
3834 on_load_entry = lookup_agent_on_load(agent);
3835 if (on_load_entry != NULL) {
3836 // switch it to the agent list -- so that Agent_OnLoad will be called,
3837 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3838 Arguments::convert_library_to_agent(agent);
3839 } else {
3840 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3841 }
3842 }
3843 }
3844 }
3846 // Create agents for -agentlib: -agentpath: and converted -Xrun
3847 // Invokes Agent_OnLoad
3848 // Called very early -- before JavaThreads exist
3849 void Threads::create_vm_init_agents() {
3850 extern struct JavaVM_ main_vm;
3851 AgentLibrary* agent;
3853 JvmtiExport::enter_onload_phase();
3855 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3856 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3858 if (on_load_entry != NULL) {
3859 // Invoke the Agent_OnLoad function
3860 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3861 if (err != JNI_OK) {
3862 vm_exit_during_initialization("agent library failed to init", agent->name());
3863 }
3864 } else {
3865 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3866 }
3867 }
3868 JvmtiExport::enter_primordial_phase();
3869 }
3871 extern "C" {
3872 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3873 }
3875 void Threads::shutdown_vm_agents() {
3876 // Send any Agent_OnUnload notifications
3877 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3878 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3879 extern struct JavaVM_ main_vm;
3880 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3882 // Find the Agent_OnUnload function.
3883 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3884 os::find_agent_function(agent,
3885 false,
3886 on_unload_symbols,
3887 num_symbol_entries));
3889 // Invoke the Agent_OnUnload function
3890 if (unload_entry != NULL) {
3891 JavaThread* thread = JavaThread::current();
3892 ThreadToNativeFromVM ttn(thread);
3893 HandleMark hm(thread);
3894 (*unload_entry)(&main_vm);
3895 }
3896 }
3897 }
3899 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3900 // Invokes JVM_OnLoad
3901 void Threads::create_vm_init_libraries() {
3902 extern struct JavaVM_ main_vm;
3903 AgentLibrary* agent;
3905 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3906 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3908 if (on_load_entry != NULL) {
3909 // Invoke the JVM_OnLoad function
3910 JavaThread* thread = JavaThread::current();
3911 ThreadToNativeFromVM ttn(thread);
3912 HandleMark hm(thread);
3913 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3914 if (err != JNI_OK) {
3915 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3916 }
3917 } else {
3918 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3919 }
3920 }
3921 }
3923 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3924 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3926 JavaThread* java_thread = NULL;
3927 // Sequential search for now. Need to do better optimization later.
3928 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3929 oop tobj = thread->threadObj();
3930 if (!thread->is_exiting() &&
3931 tobj != NULL &&
3932 java_tid == java_lang_Thread::thread_id(tobj)) {
3933 java_thread = thread;
3934 break;
3935 }
3936 }
3937 return java_thread;
3938 }
3941 // Last thread running calls java.lang.Shutdown.shutdown()
3942 void JavaThread::invoke_shutdown_hooks() {
3943 HandleMark hm(this);
3945 // We could get here with a pending exception, if so clear it now.
3946 if (this->has_pending_exception()) {
3947 this->clear_pending_exception();
3948 }
3950 EXCEPTION_MARK;
3951 Klass* k =
3952 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3953 THREAD);
3954 if (k != NULL) {
3955 // SystemDictionary::resolve_or_null will return null if there was
3956 // an exception. If we cannot load the Shutdown class, just don't
3957 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3958 // and finalizers (if runFinalizersOnExit is set) won't be run.
3959 // Note that if a shutdown hook was registered or runFinalizersOnExit
3960 // was called, the Shutdown class would have already been loaded
3961 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3962 instanceKlassHandle shutdown_klass (THREAD, k);
3963 JavaValue result(T_VOID);
3964 JavaCalls::call_static(&result,
3965 shutdown_klass,
3966 vmSymbols::shutdown_method_name(),
3967 vmSymbols::void_method_signature(),
3968 THREAD);
3969 }
3970 CLEAR_PENDING_EXCEPTION;
3971 }
3973 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3974 // the program falls off the end of main(). Another VM exit path is through
3975 // vm_exit() when the program calls System.exit() to return a value or when
3976 // there is a serious error in VM. The two shutdown paths are not exactly
3977 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3978 // and VM_Exit op at VM level.
3979 //
3980 // Shutdown sequence:
3981 // + Shutdown native memory tracking if it is on
3982 // + Wait until we are the last non-daemon thread to execute
3983 // <-- every thing is still working at this moment -->
3984 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3985 // shutdown hooks, run finalizers if finalization-on-exit
3986 // + Call before_exit(), prepare for VM exit
3987 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3988 // currently the only user of this mechanism is File.deleteOnExit())
3989 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3990 // post thread end and vm death events to JVMTI,
3991 // stop signal thread
3992 // + Call JavaThread::exit(), it will:
3993 // > release JNI handle blocks, remove stack guard pages
3994 // > remove this thread from Threads list
3995 // <-- no more Java code from this thread after this point -->
3996 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3997 // the compiler threads at safepoint
3998 // <-- do not use anything that could get blocked by Safepoint -->
3999 // + Disable tracing at JNI/JVM barriers
4000 // + Set _vm_exited flag for threads that are still running native code
4001 // + Delete this thread
4002 // + Call exit_globals()
4003 // > deletes tty
4004 // > deletes PerfMemory resources
4005 // + Return to caller
4007 bool Threads::destroy_vm() {
4008 JavaThread* thread = JavaThread::current();
4010 #ifdef ASSERT
4011 _vm_complete = false;
4012 #endif
4013 // Wait until we are the last non-daemon thread to execute
4014 { MutexLocker nu(Threads_lock);
4015 while (Threads::number_of_non_daemon_threads() > 1 )
4016 // This wait should make safepoint checks, wait without a timeout,
4017 // and wait as a suspend-equivalent condition.
4018 //
4019 // Note: If the FlatProfiler is running and this thread is waiting
4020 // for another non-daemon thread to finish, then the FlatProfiler
4021 // is waiting for the external suspend request on this thread to
4022 // complete. wait_for_ext_suspend_completion() will eventually
4023 // timeout, but that takes time. Making this wait a suspend-
4024 // equivalent condition solves that timeout problem.
4025 //
4026 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4027 Mutex::_as_suspend_equivalent_flag);
4028 }
4030 EventShutdown e;
4031 if (e.should_commit()) {
4032 e.set_reason("No remaining non-daemon Java threads");
4033 e.commit();
4034 }
4036 // Hang forever on exit if we are reporting an error.
4037 if (ShowMessageBoxOnError && is_error_reported()) {
4038 os::infinite_sleep();
4039 }
4040 os::wait_for_keypress_at_exit();
4042 if (JDK_Version::is_jdk12x_version()) {
4043 // We are the last thread running, so check if finalizers should be run.
4044 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4045 HandleMark rm(thread);
4046 Universe::run_finalizers_on_exit();
4047 } else {
4048 // run Java level shutdown hooks
4049 thread->invoke_shutdown_hooks();
4050 }
4052 before_exit(thread);
4054 thread->exit(true);
4056 // Stop VM thread.
4057 {
4058 // 4945125 The vm thread comes to a safepoint during exit.
4059 // GC vm_operations can get caught at the safepoint, and the
4060 // heap is unparseable if they are caught. Grab the Heap_lock
4061 // to prevent this. The GC vm_operations will not be able to
4062 // queue until after the vm thread is dead. After this point,
4063 // we'll never emerge out of the safepoint before the VM exits.
4065 MutexLocker ml(Heap_lock);
4067 VMThread::wait_for_vm_thread_exit();
4068 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4069 VMThread::destroy();
4070 }
4072 // clean up ideal graph printers
4073 #if defined(COMPILER2) && !defined(PRODUCT)
4074 IdealGraphPrinter::clean_up();
4075 #endif
4077 // Now, all Java threads are gone except daemon threads. Daemon threads
4078 // running Java code or in VM are stopped by the Safepoint. However,
4079 // daemon threads executing native code are still running. But they
4080 // will be stopped at native=>Java/VM barriers. Note that we can't
4081 // simply kill or suspend them, as it is inherently deadlock-prone.
4083 #ifndef PRODUCT
4084 // disable function tracing at JNI/JVM barriers
4085 TraceJNICalls = false;
4086 TraceJVMCalls = false;
4087 TraceRuntimeCalls = false;
4088 #endif
4090 VM_Exit::set_vm_exited();
4092 notify_vm_shutdown();
4094 delete thread;
4096 // exit_globals() will delete tty
4097 exit_globals();
4099 return true;
4100 }
4103 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4104 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4105 return is_supported_jni_version(version);
4106 }
4109 jboolean Threads::is_supported_jni_version(jint version) {
4110 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4111 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4112 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4113 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4114 return JNI_FALSE;
4115 }
4118 void Threads::add(JavaThread* p, bool force_daemon) {
4119 // The threads lock must be owned at this point
4120 assert_locked_or_safepoint(Threads_lock);
4122 // See the comment for this method in thread.hpp for its purpose and
4123 // why it is called here.
4124 p->initialize_queues();
4125 p->set_next(_thread_list);
4126 _thread_list = p;
4127 _number_of_threads++;
4128 oop threadObj = p->threadObj();
4129 bool daemon = true;
4130 // Bootstrapping problem: threadObj can be null for initial
4131 // JavaThread (or for threads attached via JNI)
4132 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4133 _number_of_non_daemon_threads++;
4134 daemon = false;
4135 }
4137 ThreadService::add_thread(p, daemon);
4139 // Possible GC point.
4140 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4141 }
4143 void Threads::remove(JavaThread* p) {
4144 // Extra scope needed for Thread_lock, so we can check
4145 // that we do not remove thread without safepoint code notice
4146 { MutexLocker ml(Threads_lock);
4148 assert(includes(p), "p must be present");
4150 JavaThread* current = _thread_list;
4151 JavaThread* prev = NULL;
4153 while (current != p) {
4154 prev = current;
4155 current = current->next();
4156 }
4158 if (prev) {
4159 prev->set_next(current->next());
4160 } else {
4161 _thread_list = p->next();
4162 }
4163 _number_of_threads--;
4164 oop threadObj = p->threadObj();
4165 bool daemon = true;
4166 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4167 _number_of_non_daemon_threads--;
4168 daemon = false;
4170 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4171 // on destroy_vm will wake up.
4172 if (number_of_non_daemon_threads() == 1)
4173 Threads_lock->notify_all();
4174 }
4175 ThreadService::remove_thread(p, daemon);
4177 // Make sure that safepoint code disregard this thread. This is needed since
4178 // the thread might mess around with locks after this point. This can cause it
4179 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4180 // of this thread since it is removed from the queue.
4181 p->set_terminated_value();
4182 } // unlock Threads_lock
4184 // Since Events::log uses a lock, we grab it outside the Threads_lock
4185 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4186 }
4188 // Threads_lock must be held when this is called (or must be called during a safepoint)
4189 bool Threads::includes(JavaThread* p) {
4190 assert(Threads_lock->is_locked(), "sanity check");
4191 ALL_JAVA_THREADS(q) {
4192 if (q == p ) {
4193 return true;
4194 }
4195 }
4196 return false;
4197 }
4199 // Operations on the Threads list for GC. These are not explicitly locked,
4200 // but the garbage collector must provide a safe context for them to run.
4201 // In particular, these things should never be called when the Threads_lock
4202 // is held by some other thread. (Note: the Safepoint abstraction also
4203 // uses the Threads_lock to gurantee this property. It also makes sure that
4204 // all threads gets blocked when exiting or starting).
4206 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4207 ALL_JAVA_THREADS(p) {
4208 p->oops_do(f, cld_f, cf);
4209 }
4210 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4211 }
4213 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4214 // Introduce a mechanism allowing parallel threads to claim threads as
4215 // root groups. Overhead should be small enough to use all the time,
4216 // even in sequential code.
4217 SharedHeap* sh = SharedHeap::heap();
4218 // Cannot yet substitute active_workers for n_par_threads
4219 // because of G1CollectedHeap::verify() use of
4220 // SharedHeap::process_roots(). n_par_threads == 0 will
4221 // turn off parallelism in process_roots while active_workers
4222 // is being used for parallelism elsewhere.
4223 bool is_par = sh->n_par_threads() > 0;
4224 assert(!is_par ||
4225 (SharedHeap::heap()->n_par_threads() ==
4226 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4227 int cp = SharedHeap::heap()->strong_roots_parity();
4228 ALL_JAVA_THREADS(p) {
4229 if (p->claim_oops_do(is_par, cp)) {
4230 p->oops_do(f, cld_f, cf);
4231 }
4232 }
4233 VMThread* vmt = VMThread::vm_thread();
4234 if (vmt->claim_oops_do(is_par, cp)) {
4235 vmt->oops_do(f, cld_f, cf);
4236 }
4237 }
4239 #if INCLUDE_ALL_GCS
4240 // Used by ParallelScavenge
4241 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4242 ALL_JAVA_THREADS(p) {
4243 q->enqueue(new ThreadRootsTask(p));
4244 }
4245 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4246 }
4248 // Used by Parallel Old
4249 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4250 ALL_JAVA_THREADS(p) {
4251 q->enqueue(new ThreadRootsMarkingTask(p));
4252 }
4253 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4254 }
4255 #endif // INCLUDE_ALL_GCS
4257 void Threads::nmethods_do(CodeBlobClosure* cf) {
4258 ALL_JAVA_THREADS(p) {
4259 p->nmethods_do(cf);
4260 }
4261 VMThread::vm_thread()->nmethods_do(cf);
4262 }
4264 void Threads::metadata_do(void f(Metadata*)) {
4265 ALL_JAVA_THREADS(p) {
4266 p->metadata_do(f);
4267 }
4268 }
4270 void Threads::gc_epilogue() {
4271 ALL_JAVA_THREADS(p) {
4272 p->gc_epilogue();
4273 }
4274 }
4276 void Threads::gc_prologue() {
4277 ALL_JAVA_THREADS(p) {
4278 p->gc_prologue();
4279 }
4280 }
4282 void Threads::deoptimized_wrt_marked_nmethods() {
4283 ALL_JAVA_THREADS(p) {
4284 p->deoptimized_wrt_marked_nmethods();
4285 }
4286 }
4289 // Get count Java threads that are waiting to enter the specified monitor.
4290 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4291 address monitor, bool doLock) {
4292 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4293 "must grab Threads_lock or be at safepoint");
4294 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4296 int i = 0;
4297 {
4298 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4299 ALL_JAVA_THREADS(p) {
4300 if (p->is_Compiler_thread()) continue;
4302 address pending = (address)p->current_pending_monitor();
4303 if (pending == monitor) { // found a match
4304 if (i < count) result->append(p); // save the first count matches
4305 i++;
4306 }
4307 }
4308 }
4309 return result;
4310 }
4313 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4314 assert(doLock ||
4315 Threads_lock->owned_by_self() ||
4316 SafepointSynchronize::is_at_safepoint(),
4317 "must grab Threads_lock or be at safepoint");
4319 // NULL owner means not locked so we can skip the search
4320 if (owner == NULL) return NULL;
4322 {
4323 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4324 ALL_JAVA_THREADS(p) {
4325 // first, see if owner is the address of a Java thread
4326 if (owner == (address)p) return p;
4327 }
4328 }
4329 // Cannot assert on lack of success here since this function may be
4330 // used by code that is trying to report useful problem information
4331 // like deadlock detection.
4332 if (UseHeavyMonitors) return NULL;
4334 //
4335 // If we didn't find a matching Java thread and we didn't force use of
4336 // heavyweight monitors, then the owner is the stack address of the
4337 // Lock Word in the owning Java thread's stack.
4338 //
4339 JavaThread* the_owner = NULL;
4340 {
4341 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4342 ALL_JAVA_THREADS(q) {
4343 if (q->is_lock_owned(owner)) {
4344 the_owner = q;
4345 break;
4346 }
4347 }
4348 }
4349 // cannot assert on lack of success here; see above comment
4350 return the_owner;
4351 }
4353 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4354 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4355 char buf[32];
4356 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4358 st->print_cr("Full thread dump %s (%s %s):",
4359 Abstract_VM_Version::vm_name(),
4360 Abstract_VM_Version::vm_release(),
4361 Abstract_VM_Version::vm_info_string()
4362 );
4363 st->cr();
4365 #if INCLUDE_ALL_GCS
4366 // Dump concurrent locks
4367 ConcurrentLocksDump concurrent_locks;
4368 if (print_concurrent_locks) {
4369 concurrent_locks.dump_at_safepoint();
4370 }
4371 #endif // INCLUDE_ALL_GCS
4373 ALL_JAVA_THREADS(p) {
4374 ResourceMark rm;
4375 p->print_on(st);
4376 if (print_stacks) {
4377 if (internal_format) {
4378 p->trace_stack();
4379 } else {
4380 p->print_stack_on(st);
4381 }
4382 }
4383 st->cr();
4384 #if INCLUDE_ALL_GCS
4385 if (print_concurrent_locks) {
4386 concurrent_locks.print_locks_on(p, st);
4387 }
4388 #endif // INCLUDE_ALL_GCS
4389 }
4391 VMThread::vm_thread()->print_on(st);
4392 st->cr();
4393 Universe::heap()->print_gc_threads_on(st);
4394 WatcherThread* wt = WatcherThread::watcher_thread();
4395 if (wt != NULL) {
4396 wt->print_on(st);
4397 st->cr();
4398 }
4399 CompileBroker::print_compiler_threads_on(st);
4400 st->flush();
4401 }
4403 // Threads::print_on_error() is called by fatal error handler. It's possible
4404 // that VM is not at safepoint and/or current thread is inside signal handler.
4405 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4406 // memory (even in resource area), it might deadlock the error handler.
4407 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4408 bool found_current = false;
4409 st->print_cr("Java Threads: ( => current thread )");
4410 ALL_JAVA_THREADS(thread) {
4411 bool is_current = (current == thread);
4412 found_current = found_current || is_current;
4414 st->print("%s", is_current ? "=>" : " ");
4416 st->print(PTR_FORMAT, thread);
4417 st->print(" ");
4418 thread->print_on_error(st, buf, buflen);
4419 st->cr();
4420 }
4421 st->cr();
4423 st->print_cr("Other Threads:");
4424 if (VMThread::vm_thread()) {
4425 bool is_current = (current == VMThread::vm_thread());
4426 found_current = found_current || is_current;
4427 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4429 st->print(PTR_FORMAT, VMThread::vm_thread());
4430 st->print(" ");
4431 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4432 st->cr();
4433 }
4434 WatcherThread* wt = WatcherThread::watcher_thread();
4435 if (wt != NULL) {
4436 bool is_current = (current == wt);
4437 found_current = found_current || is_current;
4438 st->print("%s", is_current ? "=>" : " ");
4440 st->print(PTR_FORMAT, wt);
4441 st->print(" ");
4442 wt->print_on_error(st, buf, buflen);
4443 st->cr();
4444 }
4445 if (!found_current) {
4446 st->cr();
4447 st->print("=>" PTR_FORMAT " (exited) ", current);
4448 current->print_on_error(st, buf, buflen);
4449 st->cr();
4450 }
4451 }
4453 // Internal SpinLock and Mutex
4454 // Based on ParkEvent
4456 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4457 //
4458 // We employ SpinLocks _only for low-contention, fixed-length
4459 // short-duration critical sections where we're concerned
4460 // about native mutex_t or HotSpot Mutex:: latency.
4461 // The mux construct provides a spin-then-block mutual exclusion
4462 // mechanism.
4463 //
4464 // Testing has shown that contention on the ListLock guarding gFreeList
4465 // is common. If we implement ListLock as a simple SpinLock it's common
4466 // for the JVM to devolve to yielding with little progress. This is true
4467 // despite the fact that the critical sections protected by ListLock are
4468 // extremely short.
4469 //
4470 // TODO-FIXME: ListLock should be of type SpinLock.
4471 // We should make this a 1st-class type, integrated into the lock
4472 // hierarchy as leaf-locks. Critically, the SpinLock structure
4473 // should have sufficient padding to avoid false-sharing and excessive
4474 // cache-coherency traffic.
4477 typedef volatile int SpinLockT ;
4479 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4480 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4481 return ; // normal fast-path return
4482 }
4484 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4485 TEVENT (SpinAcquire - ctx) ;
4486 int ctr = 0 ;
4487 int Yields = 0 ;
4488 for (;;) {
4489 while (*adr != 0) {
4490 ++ctr ;
4491 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4492 if (Yields > 5) {
4493 os::naked_short_sleep(1);
4494 } else {
4495 os::NakedYield() ;
4496 ++Yields ;
4497 }
4498 } else {
4499 SpinPause() ;
4500 }
4501 }
4502 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4503 }
4504 }
4506 void Thread::SpinRelease (volatile int * adr) {
4507 assert (*adr != 0, "invariant") ;
4508 OrderAccess::fence() ; // guarantee at least release consistency.
4509 // Roach-motel semantics.
4510 // It's safe if subsequent LDs and STs float "up" into the critical section,
4511 // but prior LDs and STs within the critical section can't be allowed
4512 // to reorder or float past the ST that releases the lock.
4513 *adr = 0 ;
4514 }
4516 // muxAcquire and muxRelease:
4517 //
4518 // * muxAcquire and muxRelease support a single-word lock-word construct.
4519 // The LSB of the word is set IFF the lock is held.
4520 // The remainder of the word points to the head of a singly-linked list
4521 // of threads blocked on the lock.
4522 //
4523 // * The current implementation of muxAcquire-muxRelease uses its own
4524 // dedicated Thread._MuxEvent instance. If we're interested in
4525 // minimizing the peak number of extant ParkEvent instances then
4526 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4527 // as certain invariants were satisfied. Specifically, care would need
4528 // to be taken with regards to consuming unpark() "permits".
4529 // A safe rule of thumb is that a thread would never call muxAcquire()
4530 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4531 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4532 // consume an unpark() permit intended for monitorenter, for instance.
4533 // One way around this would be to widen the restricted-range semaphore
4534 // implemented in park(). Another alternative would be to provide
4535 // multiple instances of the PlatformEvent() for each thread. One
4536 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4537 //
4538 // * Usage:
4539 // -- Only as leaf locks
4540 // -- for short-term locking only as muxAcquire does not perform
4541 // thread state transitions.
4542 //
4543 // Alternatives:
4544 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4545 // but with parking or spin-then-park instead of pure spinning.
4546 // * Use Taura-Oyama-Yonenzawa locks.
4547 // * It's possible to construct a 1-0 lock if we encode the lockword as
4548 // (List,LockByte). Acquire will CAS the full lockword while Release
4549 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4550 // acquiring threads use timers (ParkTimed) to detect and recover from
4551 // the stranding window. Thread/Node structures must be aligned on 256-byte
4552 // boundaries by using placement-new.
4553 // * Augment MCS with advisory back-link fields maintained with CAS().
4554 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4555 // The validity of the backlinks must be ratified before we trust the value.
4556 // If the backlinks are invalid the exiting thread must back-track through the
4557 // the forward links, which are always trustworthy.
4558 // * Add a successor indication. The LockWord is currently encoded as
4559 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4560 // to provide the usual futile-wakeup optimization.
4561 // See RTStt for details.
4562 // * Consider schedctl.sc_nopreempt to cover the critical section.
4563 //
4566 typedef volatile intptr_t MutexT ; // Mux Lock-word
4567 enum MuxBits { LOCKBIT = 1 } ;
4569 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4570 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4571 if (w == 0) return ;
4572 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4573 return ;
4574 }
4576 TEVENT (muxAcquire - Contention) ;
4577 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4578 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4579 for (;;) {
4580 int its = (os::is_MP() ? 100 : 0) + 1 ;
4582 // Optional spin phase: spin-then-park strategy
4583 while (--its >= 0) {
4584 w = *Lock ;
4585 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4586 return ;
4587 }
4588 }
4590 Self->reset() ;
4591 Self->OnList = intptr_t(Lock) ;
4592 // The following fence() isn't _strictly necessary as the subsequent
4593 // CAS() both serializes execution and ratifies the fetched *Lock value.
4594 OrderAccess::fence();
4595 for (;;) {
4596 w = *Lock ;
4597 if ((w & LOCKBIT) == 0) {
4598 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4599 Self->OnList = 0 ; // hygiene - allows stronger asserts
4600 return ;
4601 }
4602 continue ; // Interference -- *Lock changed -- Just retry
4603 }
4604 assert (w & LOCKBIT, "invariant") ;
4605 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4606 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4607 }
4609 while (Self->OnList != 0) {
4610 Self->park() ;
4611 }
4612 }
4613 }
4615 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4616 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4617 if (w == 0) return ;
4618 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4619 return ;
4620 }
4622 TEVENT (muxAcquire - Contention) ;
4623 ParkEvent * ReleaseAfter = NULL ;
4624 if (ev == NULL) {
4625 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4626 }
4627 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4628 for (;;) {
4629 guarantee (ev->OnList == 0, "invariant") ;
4630 int its = (os::is_MP() ? 100 : 0) + 1 ;
4632 // Optional spin phase: spin-then-park strategy
4633 while (--its >= 0) {
4634 w = *Lock ;
4635 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4636 if (ReleaseAfter != NULL) {
4637 ParkEvent::Release (ReleaseAfter) ;
4638 }
4639 return ;
4640 }
4641 }
4643 ev->reset() ;
4644 ev->OnList = intptr_t(Lock) ;
4645 // The following fence() isn't _strictly necessary as the subsequent
4646 // CAS() both serializes execution and ratifies the fetched *Lock value.
4647 OrderAccess::fence();
4648 for (;;) {
4649 w = *Lock ;
4650 if ((w & LOCKBIT) == 0) {
4651 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4652 ev->OnList = 0 ;
4653 // We call ::Release while holding the outer lock, thus
4654 // artificially lengthening the critical section.
4655 // Consider deferring the ::Release() until the subsequent unlock(),
4656 // after we've dropped the outer lock.
4657 if (ReleaseAfter != NULL) {
4658 ParkEvent::Release (ReleaseAfter) ;
4659 }
4660 return ;
4661 }
4662 continue ; // Interference -- *Lock changed -- Just retry
4663 }
4664 assert (w & LOCKBIT, "invariant") ;
4665 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4666 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4667 }
4669 while (ev->OnList != 0) {
4670 ev->park() ;
4671 }
4672 }
4673 }
4675 // Release() must extract a successor from the list and then wake that thread.
4676 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4677 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4678 // Release() would :
4679 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4680 // (B) Extract a successor from the private list "in-hand"
4681 // (C) attempt to CAS() the residual back into *Lock over null.
4682 // If there were any newly arrived threads and the CAS() would fail.
4683 // In that case Release() would detach the RATs, re-merge the list in-hand
4684 // with the RATs and repeat as needed. Alternately, Release() might
4685 // detach and extract a successor, but then pass the residual list to the wakee.
4686 // The wakee would be responsible for reattaching and remerging before it
4687 // competed for the lock.
4688 //
4689 // Both "pop" and DMR are immune from ABA corruption -- there can be
4690 // multiple concurrent pushers, but only one popper or detacher.
4691 // This implementation pops from the head of the list. This is unfair,
4692 // but tends to provide excellent throughput as hot threads remain hot.
4693 // (We wake recently run threads first).
4695 void Thread::muxRelease (volatile intptr_t * Lock) {
4696 for (;;) {
4697 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4698 assert (w & LOCKBIT, "invariant") ;
4699 if (w == LOCKBIT) return ;
4700 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4701 assert (List != NULL, "invariant") ;
4702 assert (List->OnList == intptr_t(Lock), "invariant") ;
4703 ParkEvent * nxt = List->ListNext ;
4705 // The following CAS() releases the lock and pops the head element.
4706 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4707 continue ;
4708 }
4709 List->OnList = 0 ;
4710 OrderAccess::fence() ;
4711 List->unpark () ;
4712 return ;
4713 }
4714 }
4717 void Threads::verify() {
4718 ALL_JAVA_THREADS(p) {
4719 p->verify();
4720 }
4721 VMThread* thread = VMThread::vm_thread();
4722 if (thread != NULL) thread->verify();
4723 }