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 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/moduleEntry.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/vmSymbols.hpp"
32 #include "code/codeCache.hpp"
33 #include "code/scopeDesc.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "compiler/compileTask.hpp"
36 #include "gc/shared/gcId.hpp"
37 #include "gc/shared/gcLocker.inline.hpp"
38 #include "gc/shared/workgroup.hpp"
39 #include "interpreter/interpreter.hpp"
40 #include "interpreter/linkResolver.hpp"
41 #include "interpreter/oopMapCache.hpp"
42 #include "jvmtifiles/jvmtiEnv.hpp"
43 #include "logging/log.hpp"
44 #include "logging/logConfiguration.hpp"
45 #include "logging/logStream.hpp"
46 #include "memory/allocation.inline.hpp"
47 #include "memory/metaspaceShared.hpp"
48 #include "memory/oopFactory.hpp"
49 #include "memory/resourceArea.hpp"
50 #include "memory/universe.hpp"
51 #include "oops/instanceKlass.hpp"
52 #include "oops/objArrayOop.hpp"
53 #include "oops/oop.inline.hpp"
54 #include "oops/symbol.hpp"
55 #include "oops/typeArrayOop.inline.hpp"
56 #include "oops/verifyOopClosure.hpp"
57 #include "prims/jvm_misc.hpp"
58 #include "prims/jvmtiExport.hpp"
59 #include "prims/jvmtiThreadState.hpp"
60 #include "prims/privilegedStack.hpp"
61 #include "runtime/arguments.hpp"
62 #include "runtime/atomic.hpp"
63 #include "runtime/biasedLocking.hpp"
64 #include "runtime/commandLineFlagConstraintList.hpp"
65 #include "runtime/commandLineFlagWriteableList.hpp"
66 #include "runtime/commandLineFlagRangeList.hpp"
67 #include "runtime/deoptimization.hpp"
68 #include "runtime/frame.inline.hpp"
69 #include "runtime/globals.hpp"
70 #include "runtime/handshake.hpp"
71 #include "runtime/init.hpp"
72 #include "runtime/interfaceSupport.hpp"
73 #include "runtime/java.hpp"
74 #include "runtime/javaCalls.hpp"
75 #include "runtime/jniHandles.inline.hpp"
76 #include "runtime/jniPeriodicChecker.hpp"
77 #include "runtime/memprofiler.hpp"
78 #include "runtime/mutexLocker.hpp"
79 #include "runtime/objectMonitor.hpp"
80 #include "runtime/orderAccess.inline.hpp"
81 #include "runtime/osThread.hpp"
82 #include "runtime/prefetch.inline.hpp"
83 #include "runtime/safepoint.hpp"
84 #include "runtime/safepointMechanism.inline.hpp"
85 #include "runtime/sharedRuntime.hpp"
86 #include "runtime/statSampler.hpp"
87 #include "runtime/stubRoutines.hpp"
88 #include "runtime/sweeper.hpp"
89 #include "runtime/task.hpp"
90 #include "runtime/thread.inline.hpp"
91 #include "runtime/threadCritical.hpp"
92 #include "runtime/threadSMR.inline.hpp"
93 #include "runtime/timer.hpp"
94 #include "runtime/timerTrace.hpp"
95 #include "runtime/vframe.hpp"
96 #include "runtime/vframeArray.hpp"
97 #include "runtime/vframe_hp.hpp"
98 #include "runtime/vmThread.hpp"
99 #include "runtime/vm_operations.hpp"
100 #include "runtime/vm_version.hpp"
101 #include "services/attachListener.hpp"
102 #include "services/management.hpp"
103 #include "services/memTracker.hpp"
104 #include "services/threadService.hpp"
105 #include "trace/traceMacros.hpp"
106 #include "trace/tracing.hpp"
107 #include "utilities/align.hpp"
108 #include "utilities/defaultStream.hpp"
109 #include "utilities/dtrace.hpp"
110 #include "utilities/events.hpp"
111 #include "utilities/macros.hpp"
112 #include "utilities/preserveException.hpp"
113 #include "utilities/vmError.hpp"
114 #if INCLUDE_ALL_GCS
115 #include "gc/cms/concurrentMarkSweepThread.hpp"
116 #include "gc/g1/concurrentMarkThread.inline.hpp"
117 #include "gc/parallel/pcTasks.hpp"
118 #endif // INCLUDE_ALL_GCS
119 #if INCLUDE_JVMCI
120 #include "jvmci/jvmciCompiler.hpp"
121 #include "jvmci/jvmciRuntime.hpp"
122 #include "logging/logHandle.hpp"
123 #endif
124 #ifdef COMPILER1
125 #include "c1/c1_Compiler.hpp"
126 #endif
127 #ifdef COMPILER2
128 #include "opto/c2compiler.hpp"
129 #include "opto/idealGraphPrinter.hpp"
130 #endif
131 #if INCLUDE_RTM_OPT
132 #include "runtime/rtmLocking.hpp"
133 #endif
134
135 // Initialization after module runtime initialization
136 void universe_post_module_init(); // must happen after call_initPhase2
137
138 #ifdef DTRACE_ENABLED
139
140 // Only bother with this argument setup if dtrace is available
141
142 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
143 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
144
145 #define DTRACE_THREAD_PROBE(probe, javathread) \
146 { \
147 ResourceMark rm(this); \
148 int len = 0; \
149 const char* name = (javathread)->get_thread_name(); \
150 len = strlen(name); \
151 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
152 (char *) name, len, \
153 java_lang_Thread::thread_id((javathread)->threadObj()), \
154 (uintptr_t) (javathread)->osthread()->thread_id(), \
155 java_lang_Thread::is_daemon((javathread)->threadObj())); \
156 }
157
158 #else // ndef DTRACE_ENABLED
159
160 #define DTRACE_THREAD_PROBE(probe, javathread)
161
162 #endif // ndef DTRACE_ENABLED
163
164 #ifndef USE_LIBRARY_BASED_TLS_ONLY
165 // Current thread is maintained as a thread-local variable
166 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
167 #endif
168 // Class hierarchy
169 // - Thread
170 // - VMThread
171 // - WatcherThread
172 // - ConcurrentMarkSweepThread
173 // - JavaThread
174 // - CompilerThread
175
176 // ======= Thread ========
177 // Support for forcing alignment of thread objects for biased locking
178 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
179 if (UseBiasedLocking) {
180 const int alignment = markOopDesc::biased_lock_alignment;
181 size_t aligned_size = size + (alignment - sizeof(intptr_t));
182 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
183 : AllocateHeap(aligned_size, flags, CURRENT_PC,
184 AllocFailStrategy::RETURN_NULL);
185 void* aligned_addr = align_up(real_malloc_addr, alignment);
186 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
187 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
188 "JavaThread alignment code overflowed allocated storage");
189 if (aligned_addr != real_malloc_addr) {
190 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
191 p2i(real_malloc_addr),
192 p2i(aligned_addr));
193 }
194 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
195 return aligned_addr;
196 } else {
197 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
198 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
199 }
200 }
201
202 void Thread::operator delete(void* p) {
203 if (UseBiasedLocking) {
204 FreeHeap(((Thread*) p)->_real_malloc_address);
205 } else {
206 FreeHeap(p);
207 }
208 }
209
210 void JavaThread::smr_delete() {
211 if (_on_thread_list) {
212 ThreadsSMRSupport::smr_delete(this);
213 } else {
214 delete this;
215 }
216 }
217
218 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
219 // JavaThread
220
221
222 Thread::Thread() {
223 // stack and get_thread
224 set_stack_base(NULL);
225 set_stack_size(0);
226 set_self_raw_id(0);
227 set_lgrp_id(-1);
228 DEBUG_ONLY(clear_suspendible_thread();)
229
230 // allocated data structures
231 set_osthread(NULL);
232 set_resource_area(new (mtThread)ResourceArea());
233 DEBUG_ONLY(_current_resource_mark = NULL;)
234 set_handle_area(new (mtThread) HandleArea(NULL));
235 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
236 set_active_handles(NULL);
237 set_free_handle_block(NULL);
238 set_last_handle_mark(NULL);
239
240 // This initial value ==> never claimed.
241 _oops_do_parity = 0;
242 _threads_hazard_ptr = NULL;
243 _nested_threads_hazard_ptr = NULL;
244 _nested_threads_hazard_ptr_cnt = 0;
245
246 // the handle mark links itself to last_handle_mark
247 new HandleMark(this);
248
249 // plain initialization
250 debug_only(_owned_locks = NULL;)
251 debug_only(_allow_allocation_count = 0;)
252 NOT_PRODUCT(_allow_safepoint_count = 0;)
253 NOT_PRODUCT(_skip_gcalot = false;)
254 _jvmti_env_iteration_count = 0;
255 set_allocated_bytes(0);
256 _vm_operation_started_count = 0;
257 _vm_operation_completed_count = 0;
258 _current_pending_monitor = NULL;
259 _current_pending_monitor_is_from_java = true;
260 _current_waiting_monitor = NULL;
261 _num_nested_signal = 0;
262 omFreeList = NULL;
263 omFreeCount = 0;
264 omFreeProvision = 32;
265 omInUseList = NULL;
266 omInUseCount = 0;
267
268 #ifdef ASSERT
269 _visited_for_critical_count = false;
270 #endif
271
272 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
273 Monitor::_safepoint_check_sometimes);
274 _suspend_flags = 0;
275
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;
281
282 _OnTrap = 0;
283 _schedctl = NULL;
284 _Stalled = 0;
285 _TypeTag = 0x2BAD;
286
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);
298
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 == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
309 "bug in forced alignment of thread objects");
310 }
311 #endif // ASSERT
312 }
313
314 void Thread::initialize_thread_current() {
315 #ifndef USE_LIBRARY_BASED_TLS_ONLY
316 assert(_thr_current == NULL, "Thread::current already initialized");
317 _thr_current = this;
318 #endif
319 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
320 ThreadLocalStorage::set_thread(this);
321 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
322 }
323
324 void Thread::clear_thread_current() {
325 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
326 #ifndef USE_LIBRARY_BASED_TLS_ONLY
327 _thr_current = NULL;
328 #endif
329 ThreadLocalStorage::set_thread(NULL);
330 }
331
332 void Thread::record_stack_base_and_size() {
333 set_stack_base(os::current_stack_base());
334 set_stack_size(os::current_stack_size());
335 // CR 7190089: on Solaris, primordial thread's stack is adjusted
336 // in initialize_thread(). Without the adjustment, stack size is
337 // incorrect if stack is set to unlimited (ulimit -s unlimited).
338 // So far, only Solaris has real implementation of initialize_thread().
339 //
340 // set up any platform-specific state.
341 os::initialize_thread(this);
342
343 // Set stack limits after thread is initialized.
344 if (is_Java_thread()) {
345 ((JavaThread*) this)->set_stack_overflow_limit();
346 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
347 }
348 #if INCLUDE_NMT
349 // record thread's native stack, stack grows downward
350 MemTracker::record_thread_stack(stack_end(), stack_size());
351 #endif // INCLUDE_NMT
352 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
353 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
354 os::current_thread_id(), p2i(stack_base() - stack_size()),
355 p2i(stack_base()), stack_size()/1024);
356 }
357
358
359 Thread::~Thread() {
360 EVENT_THREAD_DESTRUCT(this);
361
362 // stack_base can be NULL if the thread is never started or exited before
363 // record_stack_base_and_size called. Although, we would like to ensure
364 // that all started threads do call record_stack_base_and_size(), there is
365 // not proper way to enforce that.
366 #if INCLUDE_NMT
367 if (_stack_base != NULL) {
368 MemTracker::release_thread_stack(stack_end(), stack_size());
369 #ifdef ASSERT
370 set_stack_base(NULL);
371 #endif
372 }
373 #endif // INCLUDE_NMT
374
375 // deallocate data structures
376 delete resource_area();
377 // since the handle marks are using the handle area, we have to deallocated the root
378 // handle mark before deallocating the thread's handle area,
379 assert(last_handle_mark() != NULL, "check we have an element");
380 delete last_handle_mark();
381 assert(last_handle_mark() == NULL, "check we have reached the end");
382
383 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
384 // We NULL out the fields for good hygiene.
385 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
386 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
387 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
388 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
389
390 delete handle_area();
391 delete metadata_handles();
392
393 // SR_handler uses this as a termination indicator -
394 // needs to happen before os::free_thread()
395 delete _SR_lock;
396 _SR_lock = NULL;
397
398 // osthread() can be NULL, if creation of thread failed.
399 if (osthread() != NULL) os::free_thread(osthread());
400
401 // clear Thread::current if thread is deleting itself.
402 // Needed to ensure JNI correctly detects non-attached threads.
403 if (this == Thread::current()) {
404 clear_thread_current();
405 }
406
407 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
408 }
409
410 // NOTE: dummy function for assertion purpose.
411 void Thread::run() {
412 ShouldNotReachHere();
413 }
414
415 #ifdef ASSERT
416 // A JavaThread is considered "dangling" if it is not the current
417 // thread, has been added the Threads list, the system is not at a
418 // safepoint and the Thread is not "protected".
419 //
420 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
421 assert(!thread->is_Java_thread() || Thread::current() == thread ||
422 !((JavaThread *) thread)->on_thread_list() ||
423 SafepointSynchronize::is_at_safepoint() ||
424 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
425 "possibility of dangling Thread pointer");
426 }
427 #endif
428
429 ThreadPriority Thread::get_priority(const Thread* const thread) {
430 ThreadPriority priority;
431 // Can return an error!
432 (void)os::get_priority(thread, priority);
433 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
434 return priority;
435 }
436
437 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
438 debug_only(check_for_dangling_thread_pointer(thread);)
439 // Can return an error!
440 (void)os::set_priority(thread, priority);
441 }
442
443
444 void Thread::start(Thread* thread) {
445 // Start is different from resume in that its safety is guaranteed by context or
446 // being called from a Java method synchronized on the Thread object.
447 if (!DisableStartThread) {
448 if (thread->is_Java_thread()) {
449 // Initialize the thread state to RUNNABLE before starting this thread.
450 // Can not set it after the thread started because we do not know the
451 // exact thread state at that time. It could be in MONITOR_WAIT or
452 // in SLEEPING or some other state.
453 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
454 java_lang_Thread::RUNNABLE);
455 }
456 os::start_thread(thread);
457 }
458 }
459
460 // Enqueue a VM_Operation to do the job for us - sometime later
461 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
462 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
463 VMThread::execute(vm_stop);
464 }
465
466
467 // Check if an external suspend request has completed (or has been
468 // cancelled). Returns true if the thread is externally suspended and
469 // false otherwise.
470 //
471 // The bits parameter returns information about the code path through
472 // the routine. Useful for debugging:
473 //
474 // set in is_ext_suspend_completed():
475 // 0x00000001 - routine was entered
476 // 0x00000010 - routine return false at end
477 // 0x00000100 - thread exited (return false)
478 // 0x00000200 - suspend request cancelled (return false)
479 // 0x00000400 - thread suspended (return true)
480 // 0x00001000 - thread is in a suspend equivalent state (return true)
481 // 0x00002000 - thread is native and walkable (return true)
482 // 0x00004000 - thread is native_trans and walkable (needed retry)
483 //
484 // set in wait_for_ext_suspend_completion():
485 // 0x00010000 - routine was entered
486 // 0x00020000 - suspend request cancelled before loop (return false)
487 // 0x00040000 - thread suspended before loop (return true)
488 // 0x00080000 - suspend request cancelled in loop (return false)
489 // 0x00100000 - thread suspended in loop (return true)
490 // 0x00200000 - suspend not completed during retry loop (return false)
491
492 // Helper class for tracing suspend wait debug bits.
493 //
494 // 0x00000100 indicates that the target thread exited before it could
495 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
496 // 0x00080000 each indicate a cancelled suspend request so they don't
497 // count as wait failures either.
498 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
499
500 class TraceSuspendDebugBits : public StackObj {
501 private:
502 JavaThread * jt;
503 bool is_wait;
504 bool called_by_wait; // meaningful when !is_wait
505 uint32_t * bits;
506
507 public:
508 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
509 uint32_t *_bits) {
510 jt = _jt;
511 is_wait = _is_wait;
512 called_by_wait = _called_by_wait;
513 bits = _bits;
514 }
515
516 ~TraceSuspendDebugBits() {
517 if (!is_wait) {
518 #if 1
519 // By default, don't trace bits for is_ext_suspend_completed() calls.
520 // That trace is very chatty.
521 return;
522 #else
523 if (!called_by_wait) {
524 // If tracing for is_ext_suspend_completed() is enabled, then only
525 // trace calls to it from wait_for_ext_suspend_completion()
526 return;
527 }
528 #endif
529 }
530
531 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
532 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
533 MutexLocker ml(Threads_lock); // needed for get_thread_name()
534 ResourceMark rm;
535
536 tty->print_cr(
537 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
538 jt->get_thread_name(), *bits);
539
540 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
541 }
542 }
543 }
544 };
545 #undef DEBUG_FALSE_BITS
546
547
548 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
549 uint32_t *bits) {
550 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
551
552 bool did_trans_retry = false; // only do thread_in_native_trans retry once
553 bool do_trans_retry; // flag to force the retry
554
555 *bits |= 0x00000001;
556
557 do {
558 do_trans_retry = false;
559
560 if (is_exiting()) {
561 // Thread is in the process of exiting. This is always checked
562 // first to reduce the risk of dereferencing a freed JavaThread.
563 *bits |= 0x00000100;
564 return false;
565 }
566
567 if (!is_external_suspend()) {
568 // Suspend request is cancelled. This is always checked before
569 // is_ext_suspended() to reduce the risk of a rogue resume
570 // confusing the thread that made the suspend request.
571 *bits |= 0x00000200;
572 return false;
573 }
574
575 if (is_ext_suspended()) {
576 // thread is suspended
577 *bits |= 0x00000400;
578 return true;
579 }
580
581 // Now that we no longer do hard suspends of threads running
582 // native code, the target thread can be changing thread state
583 // while we are in this routine:
584 //
585 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
586 //
587 // We save a copy of the thread state as observed at this moment
588 // and make our decision about suspend completeness based on the
589 // copy. This closes the race where the thread state is seen as
590 // _thread_in_native_trans in the if-thread_blocked check, but is
591 // seen as _thread_blocked in if-thread_in_native_trans check.
592 JavaThreadState save_state = thread_state();
593
594 if (save_state == _thread_blocked && is_suspend_equivalent()) {
595 // If the thread's state is _thread_blocked and this blocking
596 // condition is known to be equivalent to a suspend, then we can
597 // consider the thread to be externally suspended. This means that
598 // the code that sets _thread_blocked has been modified to do
599 // self-suspension if the blocking condition releases. We also
600 // used to check for CONDVAR_WAIT here, but that is now covered by
601 // the _thread_blocked with self-suspension check.
602 //
603 // Return true since we wouldn't be here unless there was still an
604 // external suspend request.
605 *bits |= 0x00001000;
606 return true;
607 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
608 // Threads running native code will self-suspend on native==>VM/Java
609 // transitions. If its stack is walkable (should always be the case
610 // unless this function is called before the actual java_suspend()
611 // call), then the wait is done.
612 *bits |= 0x00002000;
613 return true;
614 } else if (!called_by_wait && !did_trans_retry &&
615 save_state == _thread_in_native_trans &&
616 frame_anchor()->walkable()) {
617 // The thread is transitioning from thread_in_native to another
618 // thread state. check_safepoint_and_suspend_for_native_trans()
619 // will force the thread to self-suspend. If it hasn't gotten
620 // there yet we may have caught the thread in-between the native
621 // code check above and the self-suspend. Lucky us. If we were
622 // called by wait_for_ext_suspend_completion(), then it
623 // will be doing the retries so we don't have to.
624 //
625 // Since we use the saved thread state in the if-statement above,
626 // there is a chance that the thread has already transitioned to
627 // _thread_blocked by the time we get here. In that case, we will
628 // make a single unnecessary pass through the logic below. This
629 // doesn't hurt anything since we still do the trans retry.
630
631 *bits |= 0x00004000;
632
633 // Once the thread leaves thread_in_native_trans for another
634 // thread state, we break out of this retry loop. We shouldn't
635 // need this flag to prevent us from getting back here, but
636 // sometimes paranoia is good.
637 did_trans_retry = true;
638
639 // We wait for the thread to transition to a more usable state.
640 for (int i = 1; i <= SuspendRetryCount; i++) {
641 // We used to do an "os::yield_all(i)" call here with the intention
642 // that yielding would increase on each retry. However, the parameter
643 // is ignored on Linux which means the yield didn't scale up. Waiting
644 // on the SR_lock below provides a much more predictable scale up for
645 // the delay. It also provides a simple/direct point to check for any
646 // safepoint requests from the VMThread
647
648 // temporarily drops SR_lock while doing wait with safepoint check
649 // (if we're a JavaThread - the WatcherThread can also call this)
650 // and increase delay with each retry
651 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
652
653 // check the actual thread state instead of what we saved above
654 if (thread_state() != _thread_in_native_trans) {
655 // the thread has transitioned to another thread state so
656 // try all the checks (except this one) one more time.
657 do_trans_retry = true;
658 break;
659 }
660 } // end retry loop
661
662
663 }
664 } while (do_trans_retry);
665
666 *bits |= 0x00000010;
667 return false;
668 }
669
670 // Wait for an external suspend request to complete (or be cancelled).
671 // Returns true if the thread is externally suspended and false otherwise.
672 //
673 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
674 uint32_t *bits) {
675 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
676 false /* !called_by_wait */, bits);
677
678 // local flag copies to minimize SR_lock hold time
679 bool is_suspended;
680 bool pending;
681 uint32_t reset_bits;
682
683 // set a marker so is_ext_suspend_completed() knows we are the caller
684 *bits |= 0x00010000;
685
686 // We use reset_bits to reinitialize the bits value at the top of
687 // each retry loop. This allows the caller to make use of any
688 // unused bits for their own marking purposes.
689 reset_bits = *bits;
690
691 {
692 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
693 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
694 delay, bits);
695 pending = is_external_suspend();
696 }
697 // must release SR_lock to allow suspension to complete
698
699 if (!pending) {
700 // A cancelled suspend request is the only false return from
701 // is_ext_suspend_completed() that keeps us from entering the
702 // retry loop.
703 *bits |= 0x00020000;
704 return false;
705 }
706
707 if (is_suspended) {
708 *bits |= 0x00040000;
709 return true;
710 }
711
712 for (int i = 1; i <= retries; i++) {
713 *bits = reset_bits; // reinit to only track last retry
714
715 // We used to do an "os::yield_all(i)" call here with the intention
716 // that yielding would increase on each retry. However, the parameter
717 // is ignored on Linux which means the yield didn't scale up. Waiting
718 // on the SR_lock below provides a much more predictable scale up for
719 // the delay. It also provides a simple/direct point to check for any
720 // safepoint requests from the VMThread
721
722 {
723 MutexLocker ml(SR_lock());
724 // wait with safepoint check (if we're a JavaThread - the WatcherThread
725 // can also call this) and increase delay with each retry
726 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
727
728 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
729 delay, bits);
730
731 // It is possible for the external suspend request to be cancelled
732 // (by a resume) before the actual suspend operation is completed.
733 // Refresh our local copy to see if we still need to wait.
734 pending = is_external_suspend();
735 }
736
737 if (!pending) {
738 // A cancelled suspend request is the only false return from
739 // is_ext_suspend_completed() that keeps us from staying in the
740 // retry loop.
741 *bits |= 0x00080000;
742 return false;
743 }
744
745 if (is_suspended) {
746 *bits |= 0x00100000;
747 return true;
748 }
749 } // end retry loop
750
751 // thread did not suspend after all our retries
752 *bits |= 0x00200000;
753 return false;
754 }
755
756 // Called from API entry points which perform stack walking. If the
757 // associated JavaThread is the current thread, then wait_for_suspend
758 // is not used. Otherwise, it determines if we should wait for the
759 // "other" thread to complete external suspension. (NOTE: in future
760 // releases the suspension mechanism should be reimplemented so this
761 // is not necessary.)
762 //
763 bool
764 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
765 if (this != JavaThread::current()) {
766 // "other" threads require special handling.
767 if (wait_for_suspend) {
768 // We are allowed to wait for the external suspend to complete
769 // so give the other thread a chance to get suspended.
770 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
771 SuspendRetryDelay, bits)) {
772 // Didn't make it so let the caller know.
773 return false;
774 }
775 }
776 // We aren't allowed to wait for the external suspend to complete
777 // so if the other thread isn't externally suspended we need to
778 // let the caller know.
779 else if (!is_ext_suspend_completed_with_lock(bits)) {
780 return false;
781 }
782 }
783
784 return true;
785 }
786
787 #ifndef PRODUCT
788 void JavaThread::record_jump(address target, address instr, const char* file,
789 int line) {
790
791 // This should not need to be atomic as the only way for simultaneous
792 // updates is via interrupts. Even then this should be rare or non-existent
793 // and we don't care that much anyway.
794
795 int index = _jmp_ring_index;
796 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
797 _jmp_ring[index]._target = (intptr_t) target;
798 _jmp_ring[index]._instruction = (intptr_t) instr;
799 _jmp_ring[index]._file = file;
800 _jmp_ring[index]._line = line;
801 }
802 #endif // PRODUCT
803
804 void Thread::interrupt(Thread* thread) {
805 debug_only(check_for_dangling_thread_pointer(thread);)
806 os::interrupt(thread);
807 }
808
809 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
810 debug_only(check_for_dangling_thread_pointer(thread);)
811 // Note: If clear_interrupted==false, this simply fetches and
812 // returns the value of the field osthread()->interrupted().
813 return os::is_interrupted(thread, clear_interrupted);
814 }
815
816
817 // GC Support
818 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
819 int thread_parity = _oops_do_parity;
820 if (thread_parity != strong_roots_parity) {
821 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
822 if (res == thread_parity) {
823 return true;
824 } else {
825 guarantee(res == strong_roots_parity, "Or else what?");
826 return false;
827 }
828 }
829 return false;
830 }
831
832 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
833 active_handles()->oops_do(f);
834 // Do oop for ThreadShadow
835 f->do_oop((oop*)&_pending_exception);
836 handle_area()->oops_do(f);
837
838 if (MonitorInUseLists) {
839 // When using thread local monitor lists, we scan them here,
840 // and the remaining global monitors in ObjectSynchronizer::oops_do().
841 ObjectSynchronizer::thread_local_used_oops_do(this, f);
842 }
843 }
844
845 void Thread::metadata_handles_do(void f(Metadata*)) {
846 // Only walk the Handles in Thread.
847 if (metadata_handles() != NULL) {
848 for (int i = 0; i< metadata_handles()->length(); i++) {
849 f(metadata_handles()->at(i));
850 }
851 }
852 }
853
854 void Thread::print_on(outputStream* st) const {
855 // get_priority assumes osthread initialized
856 if (osthread() != NULL) {
857 int os_prio;
858 if (os::get_native_priority(this, &os_prio) == OS_OK) {
859 st->print("os_prio=%d ", os_prio);
860 }
861 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
862 osthread()->print_on(st);
863 }
864 if (_threads_hazard_ptr != NULL) {
865 st->print("_threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
866 }
867 if (_nested_threads_hazard_ptr != NULL) {
868 print_nested_threads_hazard_ptrs_on(st);
869 }
870 st->print(" ");
871 debug_only(if (WizardMode) print_owned_locks_on(st);)
872 }
873
874 void Thread::print_nested_threads_hazard_ptrs_on(outputStream* st) const {
875 assert(_nested_threads_hazard_ptr != NULL, "must be set to print");
876
877 if (EnableThreadSMRStatistics) {
878 st->print(", _nested_threads_hazard_ptr_cnt=%u", _nested_threads_hazard_ptr_cnt);
879 }
880 st->print(", _nested_threads_hazard_ptrs=");
881 for (NestedThreadsList* node = _nested_threads_hazard_ptr; node != NULL;
882 node = node->next()) {
883 if (node != _nested_threads_hazard_ptr) {
884 // First node does not need a comma-space separator.
885 st->print(", ");
886 }
887 st->print(INTPTR_FORMAT, p2i(node->t_list()));
888 }
889 }
890
891 // Thread::print_on_error() is called by fatal error handler. Don't use
892 // any lock or allocate memory.
893 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
894 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
895
896 if (is_VM_thread()) { st->print("VMThread"); }
897 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
898 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
899 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
900 else { st->print("Thread"); }
901
902 if (is_Named_thread()) {
903 st->print(" \"%s\"", name());
904 }
905
906 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
907 p2i(stack_end()), p2i(stack_base()));
908
909 if (osthread()) {
910 st->print(" [id=%d]", osthread()->thread_id());
911 }
912
913 if (_threads_hazard_ptr != NULL) {
914 st->print(" _threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
915 }
916 if (_nested_threads_hazard_ptr != NULL) {
917 print_nested_threads_hazard_ptrs_on(st);
918 }
919 }
920
921 void Thread::print_value_on(outputStream* st) const {
922 if (is_Named_thread()) {
923 st->print(" \"%s\" ", name());
924 }
925 st->print(INTPTR_FORMAT, p2i(this)); // print address
926 }
927
928 #ifdef ASSERT
929 void Thread::print_owned_locks_on(outputStream* st) const {
930 Monitor *cur = _owned_locks;
931 if (cur == NULL) {
932 st->print(" (no locks) ");
933 } else {
934 st->print_cr(" Locks owned:");
935 while (cur) {
936 cur->print_on(st);
937 cur = cur->next();
938 }
939 }
940 }
941
942 static int ref_use_count = 0;
943
944 bool Thread::owns_locks_but_compiled_lock() const {
945 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
946 if (cur != Compile_lock) return true;
947 }
948 return false;
949 }
950
951
952 #endif
953
954 #ifndef PRODUCT
955
956 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
957 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
958 // no threads which allow_vm_block's are held
959 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
960 // Check if current thread is allowed to block at a safepoint
961 if (!(_allow_safepoint_count == 0)) {
962 fatal("Possible safepoint reached by thread that does not allow it");
963 }
964 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
965 fatal("LEAF method calling lock?");
966 }
967
968 #ifdef ASSERT
969 if (potential_vm_operation && is_Java_thread()
970 && !Universe::is_bootstrapping()) {
971 // Make sure we do not hold any locks that the VM thread also uses.
972 // This could potentially lead to deadlocks
973 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
974 // Threads_lock is special, since the safepoint synchronization will not start before this is
975 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
976 // since it is used to transfer control between JavaThreads and the VMThread
977 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
978 if ((cur->allow_vm_block() &&
979 cur != Threads_lock &&
980 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
981 cur != VMOperationRequest_lock &&
982 cur != VMOperationQueue_lock) ||
983 cur->rank() == Mutex::special) {
984 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
985 }
986 }
987 }
988
989 if (GCALotAtAllSafepoints) {
990 // We could enter a safepoint here and thus have a gc
991 InterfaceSupport::check_gc_alot();
992 }
993 #endif
994 }
995 #endif
996
997 bool Thread::is_in_stack(address adr) const {
998 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
999 address end = os::current_stack_pointer();
1000 // Allow non Java threads to call this without stack_base
1001 if (_stack_base == NULL) return true;
1002 if (stack_base() >= adr && adr >= end) return true;
1003
1004 return false;
1005 }
1006
1007 bool Thread::is_in_usable_stack(address adr) const {
1008 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1009 size_t usable_stack_size = _stack_size - stack_guard_size;
1010
1011 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1012 }
1013
1014
1015 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1016 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1017 // used for compilation in the future. If that change is made, the need for these methods
1018 // should be revisited, and they should be removed if possible.
1019
1020 bool Thread::is_lock_owned(address adr) const {
1021 return on_local_stack(adr);
1022 }
1023
1024 bool Thread::set_as_starting_thread() {
1025 // NOTE: this must be called inside the main thread.
1026 return os::create_main_thread((JavaThread*)this);
1027 }
1028
1029 static void initialize_class(Symbol* class_name, TRAPS) {
1030 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1031 InstanceKlass::cast(klass)->initialize(CHECK);
1032 }
1033
1034
1035 // Creates the initial ThreadGroup
1036 static Handle create_initial_thread_group(TRAPS) {
1037 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1038 InstanceKlass* ik = InstanceKlass::cast(k);
1039
1040 Handle system_instance = ik->allocate_instance_handle(CHECK_NH);
1041 {
1042 JavaValue result(T_VOID);
1043 JavaCalls::call_special(&result,
1044 system_instance,
1045 ik,
1046 vmSymbols::object_initializer_name(),
1047 vmSymbols::void_method_signature(),
1048 CHECK_NH);
1049 }
1050 Universe::set_system_thread_group(system_instance());
1051
1052 Handle main_instance = ik->allocate_instance_handle(CHECK_NH);
1053 {
1054 JavaValue result(T_VOID);
1055 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1056 JavaCalls::call_special(&result,
1057 main_instance,
1058 ik,
1059 vmSymbols::object_initializer_name(),
1060 vmSymbols::threadgroup_string_void_signature(),
1061 system_instance,
1062 string,
1063 CHECK_NH);
1064 }
1065 return main_instance;
1066 }
1067
1068 // Creates the initial Thread
1069 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1070 TRAPS) {
1071 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1072 InstanceKlass* ik = InstanceKlass::cast(k);
1073 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1074
1075 java_lang_Thread::set_thread(thread_oop(), thread);
1076 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1077 thread->set_threadObj(thread_oop());
1078
1079 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1080
1081 JavaValue result(T_VOID);
1082 JavaCalls::call_special(&result, thread_oop,
1083 ik,
1084 vmSymbols::object_initializer_name(),
1085 vmSymbols::threadgroup_string_void_signature(),
1086 thread_group,
1087 string,
1088 CHECK_NULL);
1089 return thread_oop();
1090 }
1091
1092 char java_runtime_name[128] = "";
1093 char java_runtime_version[128] = "";
1094
1095 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1096 static const char* get_java_runtime_name(TRAPS) {
1097 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1098 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1099 fieldDescriptor fd;
1100 bool found = k != NULL &&
1101 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1102 vmSymbols::string_signature(), &fd);
1103 if (found) {
1104 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1105 if (name_oop == NULL) {
1106 return NULL;
1107 }
1108 const char* name = java_lang_String::as_utf8_string(name_oop,
1109 java_runtime_name,
1110 sizeof(java_runtime_name));
1111 return name;
1112 } else {
1113 return NULL;
1114 }
1115 }
1116
1117 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1118 static const char* get_java_runtime_version(TRAPS) {
1119 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1120 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1121 fieldDescriptor fd;
1122 bool found = k != NULL &&
1123 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1124 vmSymbols::string_signature(), &fd);
1125 if (found) {
1126 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1127 if (name_oop == NULL) {
1128 return NULL;
1129 }
1130 const char* name = java_lang_String::as_utf8_string(name_oop,
1131 java_runtime_version,
1132 sizeof(java_runtime_version));
1133 return name;
1134 } else {
1135 return NULL;
1136 }
1137 }
1138
1139 // General purpose hook into Java code, run once when the VM is initialized.
1140 // The Java library method itself may be changed independently from the VM.
1141 static void call_postVMInitHook(TRAPS) {
1142 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1143 if (klass != NULL) {
1144 JavaValue result(T_VOID);
1145 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1146 vmSymbols::void_method_signature(),
1147 CHECK);
1148 }
1149 }
1150
1151 static void reset_vm_info_property(TRAPS) {
1152 // the vm info string
1153 ResourceMark rm(THREAD);
1154 const char *vm_info = VM_Version::vm_info_string();
1155
1156 // java.lang.System class
1157 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1158
1159 // setProperty arguments
1160 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1161 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1162
1163 // return value
1164 JavaValue r(T_OBJECT);
1165
1166 // public static String setProperty(String key, String value);
1167 JavaCalls::call_static(&r,
1168 klass,
1169 vmSymbols::setProperty_name(),
1170 vmSymbols::string_string_string_signature(),
1171 key_str,
1172 value_str,
1173 CHECK);
1174 }
1175
1176
1177 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1178 bool daemon, TRAPS) {
1179 assert(thread_group.not_null(), "thread group should be specified");
1180 assert(threadObj() == NULL, "should only create Java thread object once");
1181
1182 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1183 InstanceKlass* ik = InstanceKlass::cast(k);
1184 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1185
1186 java_lang_Thread::set_thread(thread_oop(), this);
1187 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1188 set_threadObj(thread_oop());
1189
1190 JavaValue result(T_VOID);
1191 if (thread_name != NULL) {
1192 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1193 // Thread gets assigned specified name and null target
1194 JavaCalls::call_special(&result,
1195 thread_oop,
1196 ik,
1197 vmSymbols::object_initializer_name(),
1198 vmSymbols::threadgroup_string_void_signature(),
1199 thread_group, // Argument 1
1200 name, // Argument 2
1201 THREAD);
1202 } else {
1203 // Thread gets assigned name "Thread-nnn" and null target
1204 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1205 JavaCalls::call_special(&result,
1206 thread_oop,
1207 ik,
1208 vmSymbols::object_initializer_name(),
1209 vmSymbols::threadgroup_runnable_void_signature(),
1210 thread_group, // Argument 1
1211 Handle(), // Argument 2
1212 THREAD);
1213 }
1214
1215
1216 if (daemon) {
1217 java_lang_Thread::set_daemon(thread_oop());
1218 }
1219
1220 if (HAS_PENDING_EXCEPTION) {
1221 return;
1222 }
1223
1224 Klass* group = SystemDictionary::ThreadGroup_klass();
1225 Handle threadObj(THREAD, this->threadObj());
1226
1227 JavaCalls::call_special(&result,
1228 thread_group,
1229 group,
1230 vmSymbols::add_method_name(),
1231 vmSymbols::thread_void_signature(),
1232 threadObj, // Arg 1
1233 THREAD);
1234 }
1235
1236 // NamedThread -- non-JavaThread subclasses with multiple
1237 // uniquely named instances should derive from this.
1238 NamedThread::NamedThread() : Thread() {
1239 _name = NULL;
1240 _processed_thread = NULL;
1241 _gc_id = GCId::undefined();
1242 }
1243
1244 NamedThread::~NamedThread() {
1245 if (_name != NULL) {
1246 FREE_C_HEAP_ARRAY(char, _name);
1247 _name = NULL;
1248 }
1249 }
1250
1251 void NamedThread::set_name(const char* format, ...) {
1252 guarantee(_name == NULL, "Only get to set name once.");
1253 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1254 guarantee(_name != NULL, "alloc failure");
1255 va_list ap;
1256 va_start(ap, format);
1257 jio_vsnprintf(_name, max_name_len, format, ap);
1258 va_end(ap);
1259 }
1260
1261 void NamedThread::initialize_named_thread() {
1262 set_native_thread_name(name());
1263 }
1264
1265 void NamedThread::print_on(outputStream* st) const {
1266 st->print("\"%s\" ", name());
1267 Thread::print_on(st);
1268 st->cr();
1269 }
1270
1271
1272 // ======= WatcherThread ========
1273
1274 // The watcher thread exists to simulate timer interrupts. It should
1275 // be replaced by an abstraction over whatever native support for
1276 // timer interrupts exists on the platform.
1277
1278 WatcherThread* WatcherThread::_watcher_thread = NULL;
1279 bool WatcherThread::_startable = false;
1280 volatile bool WatcherThread::_should_terminate = false;
1281
1282 WatcherThread::WatcherThread() : Thread() {
1283 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1284 if (os::create_thread(this, os::watcher_thread)) {
1285 _watcher_thread = this;
1286
1287 // Set the watcher thread to the highest OS priority which should not be
1288 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1289 // is created. The only normal thread using this priority is the reference
1290 // handler thread, which runs for very short intervals only.
1291 // If the VMThread's priority is not lower than the WatcherThread profiling
1292 // will be inaccurate.
1293 os::set_priority(this, MaxPriority);
1294 if (!DisableStartThread) {
1295 os::start_thread(this);
1296 }
1297 }
1298 }
1299
1300 int WatcherThread::sleep() const {
1301 // The WatcherThread does not participate in the safepoint protocol
1302 // for the PeriodicTask_lock because it is not a JavaThread.
1303 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1304
1305 if (_should_terminate) {
1306 // check for termination before we do any housekeeping or wait
1307 return 0; // we did not sleep.
1308 }
1309
1310 // remaining will be zero if there are no tasks,
1311 // causing the WatcherThread to sleep until a task is
1312 // enrolled
1313 int remaining = PeriodicTask::time_to_wait();
1314 int time_slept = 0;
1315
1316 // we expect this to timeout - we only ever get unparked when
1317 // we should terminate or when a new task has been enrolled
1318 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1319
1320 jlong time_before_loop = os::javaTimeNanos();
1321
1322 while (true) {
1323 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1324 remaining);
1325 jlong now = os::javaTimeNanos();
1326
1327 if (remaining == 0) {
1328 // if we didn't have any tasks we could have waited for a long time
1329 // consider the time_slept zero and reset time_before_loop
1330 time_slept = 0;
1331 time_before_loop = now;
1332 } else {
1333 // need to recalculate since we might have new tasks in _tasks
1334 time_slept = (int) ((now - time_before_loop) / 1000000);
1335 }
1336
1337 // Change to task list or spurious wakeup of some kind
1338 if (timedout || _should_terminate) {
1339 break;
1340 }
1341
1342 remaining = PeriodicTask::time_to_wait();
1343 if (remaining == 0) {
1344 // Last task was just disenrolled so loop around and wait until
1345 // another task gets enrolled
1346 continue;
1347 }
1348
1349 remaining -= time_slept;
1350 if (remaining <= 0) {
1351 break;
1352 }
1353 }
1354
1355 return time_slept;
1356 }
1357
1358 void WatcherThread::run() {
1359 assert(this == watcher_thread(), "just checking");
1360
1361 this->record_stack_base_and_size();
1362 this->set_native_thread_name(this->name());
1363 this->set_active_handles(JNIHandleBlock::allocate_block());
1364 while (true) {
1365 assert(watcher_thread() == Thread::current(), "thread consistency check");
1366 assert(watcher_thread() == this, "thread consistency check");
1367
1368 // Calculate how long it'll be until the next PeriodicTask work
1369 // should be done, and sleep that amount of time.
1370 int time_waited = sleep();
1371
1372 if (VMError::is_error_reported()) {
1373 // A fatal error has happened, the error handler(VMError::report_and_die)
1374 // should abort JVM after creating an error log file. However in some
1375 // rare cases, the error handler itself might deadlock. Here periodically
1376 // check for error reporting timeouts, and if it happens, just proceed to
1377 // abort the VM.
1378
1379 // This code is in WatcherThread because WatcherThread wakes up
1380 // periodically so the fatal error handler doesn't need to do anything;
1381 // also because the WatcherThread is less likely to crash than other
1382 // threads.
1383
1384 for (;;) {
1385 // Note: we use naked sleep in this loop because we want to avoid using
1386 // any kind of VM infrastructure which may be broken at this point.
1387 if (VMError::check_timeout()) {
1388 // We hit error reporting timeout. Error reporting was interrupted and
1389 // will be wrapping things up now (closing files etc). Give it some more
1390 // time, then quit the VM.
1391 os::naked_short_sleep(200);
1392 // Print a message to stderr.
1393 fdStream err(defaultStream::output_fd());
1394 err.print_raw_cr("# [ timer expired, abort... ]");
1395 // skip atexit/vm_exit/vm_abort hooks
1396 os::die();
1397 }
1398
1399 // Wait a second, then recheck for timeout.
1400 os::naked_short_sleep(999);
1401 }
1402 }
1403
1404 if (_should_terminate) {
1405 // check for termination before posting the next tick
1406 break;
1407 }
1408
1409 PeriodicTask::real_time_tick(time_waited);
1410 }
1411
1412 // Signal that it is terminated
1413 {
1414 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1415 _watcher_thread = NULL;
1416 Terminator_lock->notify();
1417 }
1418 }
1419
1420 void WatcherThread::start() {
1421 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1422
1423 if (watcher_thread() == NULL && _startable) {
1424 _should_terminate = false;
1425 // Create the single instance of WatcherThread
1426 new WatcherThread();
1427 }
1428 }
1429
1430 void WatcherThread::make_startable() {
1431 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1432 _startable = true;
1433 }
1434
1435 void WatcherThread::stop() {
1436 {
1437 // Follow normal safepoint aware lock enter protocol since the
1438 // WatcherThread is stopped by another JavaThread.
1439 MutexLocker ml(PeriodicTask_lock);
1440 _should_terminate = true;
1441
1442 WatcherThread* watcher = watcher_thread();
1443 if (watcher != NULL) {
1444 // unpark the WatcherThread so it can see that it should terminate
1445 watcher->unpark();
1446 }
1447 }
1448
1449 MutexLocker mu(Terminator_lock);
1450
1451 while (watcher_thread() != NULL) {
1452 // This wait should make safepoint checks, wait without a timeout,
1453 // and wait as a suspend-equivalent condition.
1454 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1455 Mutex::_as_suspend_equivalent_flag);
1456 }
1457 }
1458
1459 void WatcherThread::unpark() {
1460 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1461 PeriodicTask_lock->notify();
1462 }
1463
1464 void WatcherThread::print_on(outputStream* st) const {
1465 st->print("\"%s\" ", name());
1466 Thread::print_on(st);
1467 st->cr();
1468 }
1469
1470 // ======= JavaThread ========
1471
1472 #if INCLUDE_JVMCI
1473
1474 jlong* JavaThread::_jvmci_old_thread_counters;
1475
1476 bool jvmci_counters_include(JavaThread* thread) {
1477 oop threadObj = thread->threadObj();
1478 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1479 }
1480
1481 void JavaThread::collect_counters(typeArrayOop array) {
1482 if (JVMCICounterSize > 0) {
1483 MutexLocker tl(Threads_lock);
1484 JavaThreadIteratorWithHandle jtiwh;
1485 for (int i = 0; i < array->length(); i++) {
1486 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1487 }
1488 for (; JavaThread *tp = jtiwh.next(); ) {
1489 if (jvmci_counters_include(tp)) {
1490 for (int i = 0; i < array->length(); i++) {
1491 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1492 }
1493 }
1494 }
1495 }
1496 }
1497
1498 #endif // INCLUDE_JVMCI
1499
1500 // A JavaThread is a normal Java thread
1501
1502 void JavaThread::initialize() {
1503 // Initialize fields
1504
1505 set_saved_exception_pc(NULL);
1506 set_threadObj(NULL);
1507 _anchor.clear();
1508 set_entry_point(NULL);
1509 set_jni_functions(jni_functions());
1510 set_callee_target(NULL);
1511 set_vm_result(NULL);
1512 set_vm_result_2(NULL);
1513 set_vframe_array_head(NULL);
1514 set_vframe_array_last(NULL);
1515 set_deferred_locals(NULL);
1516 set_deopt_mark(NULL);
1517 set_deopt_compiled_method(NULL);
1518 clear_must_deopt_id();
1519 set_monitor_chunks(NULL);
1520 set_next(NULL);
1521 _on_thread_list = false;
1522 set_thread_state(_thread_new);
1523 _terminated = _not_terminated;
1524 _privileged_stack_top = NULL;
1525 _array_for_gc = NULL;
1526 _suspend_equivalent = false;
1527 _in_deopt_handler = 0;
1528 _doing_unsafe_access = false;
1529 _stack_guard_state = stack_guard_unused;
1530 #if INCLUDE_JVMCI
1531 _pending_monitorenter = false;
1532 _pending_deoptimization = -1;
1533 _pending_failed_speculation = NULL;
1534 _pending_transfer_to_interpreter = false;
1535 _adjusting_comp_level = false;
1536 _jvmci._alternate_call_target = NULL;
1537 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1538 if (JVMCICounterSize > 0) {
1539 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1540 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1541 } else {
1542 _jvmci_counters = NULL;
1543 }
1544 #endif // INCLUDE_JVMCI
1545 _reserved_stack_activation = NULL; // stack base not known yet
1546 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1547 _exception_pc = 0;
1548 _exception_handler_pc = 0;
1549 _is_method_handle_return = 0;
1550 _jvmti_thread_state= NULL;
1551 _should_post_on_exceptions_flag = JNI_FALSE;
1552 _jvmti_get_loaded_classes_closure = NULL;
1553 _interp_only_mode = 0;
1554 _special_runtime_exit_condition = _no_async_condition;
1555 _pending_async_exception = NULL;
1556 _thread_stat = NULL;
1557 _thread_stat = new ThreadStatistics();
1558 _blocked_on_compilation = false;
1559 _jni_active_critical = 0;
1560 _pending_jni_exception_check_fn = NULL;
1561 _do_not_unlock_if_synchronized = false;
1562 _cached_monitor_info = NULL;
1563 _parker = Parker::Allocate(this);
1564
1565 #ifndef PRODUCT
1566 _jmp_ring_index = 0;
1567 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1568 record_jump(NULL, NULL, NULL, 0);
1569 }
1570 #endif // PRODUCT
1571
1572 // Setup safepoint state info for this thread
1573 ThreadSafepointState::create(this);
1574
1575 debug_only(_java_call_counter = 0);
1576
1577 // JVMTI PopFrame support
1578 _popframe_condition = popframe_inactive;
1579 _popframe_preserved_args = NULL;
1580 _popframe_preserved_args_size = 0;
1581 _frames_to_pop_failed_realloc = 0;
1582
1583 if (SafepointMechanism::uses_thread_local_poll()) {
1584 SafepointMechanism::initialize_header(this);
1585 }
1586
1587 pd_initialize();
1588 }
1589
1590 #if INCLUDE_ALL_GCS
1591 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1592 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1593 #endif // INCLUDE_ALL_GCS
1594
1595 JavaThread::JavaThread(bool is_attaching_via_jni) :
1596 Thread()
1597 #if INCLUDE_ALL_GCS
1598 , _satb_mark_queue(&_satb_mark_queue_set),
1599 _dirty_card_queue(&_dirty_card_queue_set)
1600 #endif // INCLUDE_ALL_GCS
1601 {
1602 initialize();
1603 if (is_attaching_via_jni) {
1604 _jni_attach_state = _attaching_via_jni;
1605 } else {
1606 _jni_attach_state = _not_attaching_via_jni;
1607 }
1608 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1609 }
1610
1611 bool JavaThread::reguard_stack(address cur_sp) {
1612 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1613 && _stack_guard_state != stack_guard_reserved_disabled) {
1614 return true; // Stack already guarded or guard pages not needed.
1615 }
1616
1617 if (register_stack_overflow()) {
1618 // For those architectures which have separate register and
1619 // memory stacks, we must check the register stack to see if
1620 // it has overflowed.
1621 return false;
1622 }
1623
1624 // Java code never executes within the yellow zone: the latter is only
1625 // there to provoke an exception during stack banging. If java code
1626 // is executing there, either StackShadowPages should be larger, or
1627 // some exception code in c1, c2 or the interpreter isn't unwinding
1628 // when it should.
1629 guarantee(cur_sp > stack_reserved_zone_base(),
1630 "not enough space to reguard - increase StackShadowPages");
1631 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1632 enable_stack_yellow_reserved_zone();
1633 if (reserved_stack_activation() != stack_base()) {
1634 set_reserved_stack_activation(stack_base());
1635 }
1636 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1637 set_reserved_stack_activation(stack_base());
1638 enable_stack_reserved_zone();
1639 }
1640 return true;
1641 }
1642
1643 bool JavaThread::reguard_stack(void) {
1644 return reguard_stack(os::current_stack_pointer());
1645 }
1646
1647
1648 void JavaThread::block_if_vm_exited() {
1649 if (_terminated == _vm_exited) {
1650 // _vm_exited is set at safepoint, and Threads_lock is never released
1651 // we will block here forever
1652 Threads_lock->lock_without_safepoint_check();
1653 ShouldNotReachHere();
1654 }
1655 }
1656
1657
1658 // Remove this ifdef when C1 is ported to the compiler interface.
1659 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1660 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1661
1662 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1663 Thread()
1664 #if INCLUDE_ALL_GCS
1665 , _satb_mark_queue(&_satb_mark_queue_set),
1666 _dirty_card_queue(&_dirty_card_queue_set)
1667 #endif // INCLUDE_ALL_GCS
1668 {
1669 initialize();
1670 _jni_attach_state = _not_attaching_via_jni;
1671 set_entry_point(entry_point);
1672 // Create the native thread itself.
1673 // %note runtime_23
1674 os::ThreadType thr_type = os::java_thread;
1675 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1676 os::java_thread;
1677 os::create_thread(this, thr_type, stack_sz);
1678 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1679 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1680 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1681 // the exception consists of creating the exception object & initializing it, initialization
1682 // will leave the VM via a JavaCall and then all locks must be unlocked).
1683 //
1684 // The thread is still suspended when we reach here. Thread must be explicit started
1685 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1686 // by calling Threads:add. The reason why this is not done here, is because the thread
1687 // object must be fully initialized (take a look at JVM_Start)
1688 }
1689
1690 JavaThread::~JavaThread() {
1691
1692 // JSR166 -- return the parker to the free list
1693 Parker::Release(_parker);
1694 _parker = NULL;
1695
1696 // Free any remaining previous UnrollBlock
1697 vframeArray* old_array = vframe_array_last();
1698
1699 if (old_array != NULL) {
1700 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1701 old_array->set_unroll_block(NULL);
1702 delete old_info;
1703 delete old_array;
1704 }
1705
1706 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1707 if (deferred != NULL) {
1708 // This can only happen if thread is destroyed before deoptimization occurs.
1709 assert(deferred->length() != 0, "empty array!");
1710 do {
1711 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1712 deferred->remove_at(0);
1713 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1714 delete dlv;
1715 } while (deferred->length() != 0);
1716 delete deferred;
1717 }
1718
1719 // All Java related clean up happens in exit
1720 ThreadSafepointState::destroy(this);
1721 if (_thread_stat != NULL) delete _thread_stat;
1722
1723 #if INCLUDE_JVMCI
1724 if (JVMCICounterSize > 0) {
1725 if (jvmci_counters_include(this)) {
1726 for (int i = 0; i < JVMCICounterSize; i++) {
1727 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1728 }
1729 }
1730 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1731 }
1732 #endif // INCLUDE_JVMCI
1733 }
1734
1735
1736 // The first routine called by a new Java thread
1737 void JavaThread::run() {
1738 // initialize thread-local alloc buffer related fields
1739 this->initialize_tlab();
1740
1741 // used to test validity of stack trace backs
1742 this->record_base_of_stack_pointer();
1743
1744 // Record real stack base and size.
1745 this->record_stack_base_and_size();
1746
1747 this->create_stack_guard_pages();
1748
1749 this->cache_global_variables();
1750
1751 // Thread is now sufficient initialized to be handled by the safepoint code as being
1752 // in the VM. Change thread state from _thread_new to _thread_in_vm
1753 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1754
1755 assert(JavaThread::current() == this, "sanity check");
1756 assert(!Thread::current()->owns_locks(), "sanity check");
1757
1758 DTRACE_THREAD_PROBE(start, this);
1759
1760 // This operation might block. We call that after all safepoint checks for a new thread has
1761 // been completed.
1762 this->set_active_handles(JNIHandleBlock::allocate_block());
1763
1764 if (JvmtiExport::should_post_thread_life()) {
1765 JvmtiExport::post_thread_start(this);
1766 }
1767
1768 EventThreadStart event;
1769 if (event.should_commit()) {
1770 event.set_thread(THREAD_TRACE_ID(this));
1771 event.commit();
1772 }
1773
1774 // We call another function to do the rest so we are sure that the stack addresses used
1775 // from there will be lower than the stack base just computed
1776 thread_main_inner();
1777
1778 // Note, thread is no longer valid at this point!
1779 }
1780
1781
1782 void JavaThread::thread_main_inner() {
1783 assert(JavaThread::current() == this, "sanity check");
1784 assert(this->threadObj() != NULL, "just checking");
1785
1786 // Execute thread entry point unless this thread has a pending exception
1787 // or has been stopped before starting.
1788 // Note: Due to JVM_StopThread we can have pending exceptions already!
1789 if (!this->has_pending_exception() &&
1790 !java_lang_Thread::is_stillborn(this->threadObj())) {
1791 {
1792 ResourceMark rm(this);
1793 this->set_native_thread_name(this->get_thread_name());
1794 }
1795 HandleMark hm(this);
1796 this->entry_point()(this, this);
1797 }
1798
1799 DTRACE_THREAD_PROBE(stop, this);
1800
1801 this->exit(false);
1802 this->smr_delete();
1803 }
1804
1805
1806 static void ensure_join(JavaThread* thread) {
1807 // We do not need to grab the Threads_lock, since we are operating on ourself.
1808 Handle threadObj(thread, thread->threadObj());
1809 assert(threadObj.not_null(), "java thread object must exist");
1810 ObjectLocker lock(threadObj, thread);
1811 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1812 thread->clear_pending_exception();
1813 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1814 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1815 // Clear the native thread instance - this makes isAlive return false and allows the join()
1816 // to complete once we've done the notify_all below
1817 java_lang_Thread::set_thread(threadObj(), NULL);
1818 lock.notify_all(thread);
1819 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1820 thread->clear_pending_exception();
1821 }
1822
1823
1824 // For any new cleanup additions, please check to see if they need to be applied to
1825 // cleanup_failed_attach_current_thread as well.
1826 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1827 assert(this == JavaThread::current(), "thread consistency check");
1828
1829 elapsedTimer _timer_exit_phase1;
1830 elapsedTimer _timer_exit_phase2;
1831 elapsedTimer _timer_exit_phase3;
1832 elapsedTimer _timer_exit_phase4;
1833
1834 if (log_is_enabled(Debug, os, thread, timer)) {
1835 _timer_exit_phase1.start();
1836 }
1837
1838 HandleMark hm(this);
1839 Handle uncaught_exception(this, this->pending_exception());
1840 this->clear_pending_exception();
1841 Handle threadObj(this, this->threadObj());
1842 assert(threadObj.not_null(), "Java thread object should be created");
1843
1844 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1845 {
1846 EXCEPTION_MARK;
1847
1848 CLEAR_PENDING_EXCEPTION;
1849 }
1850 if (!destroy_vm) {
1851 if (uncaught_exception.not_null()) {
1852 EXCEPTION_MARK;
1853 // Call method Thread.dispatchUncaughtException().
1854 Klass* thread_klass = SystemDictionary::Thread_klass();
1855 JavaValue result(T_VOID);
1856 JavaCalls::call_virtual(&result,
1857 threadObj, thread_klass,
1858 vmSymbols::dispatchUncaughtException_name(),
1859 vmSymbols::throwable_void_signature(),
1860 uncaught_exception,
1861 THREAD);
1862 if (HAS_PENDING_EXCEPTION) {
1863 ResourceMark rm(this);
1864 jio_fprintf(defaultStream::error_stream(),
1865 "\nException: %s thrown from the UncaughtExceptionHandler"
1866 " in thread \"%s\"\n",
1867 pending_exception()->klass()->external_name(),
1868 get_thread_name());
1869 CLEAR_PENDING_EXCEPTION;
1870 }
1871 }
1872
1873 // Called before the java thread exit since we want to read info
1874 // from java_lang_Thread object
1875 EventThreadEnd event;
1876 if (event.should_commit()) {
1877 event.set_thread(THREAD_TRACE_ID(this));
1878 event.commit();
1879 }
1880
1881 // Call after last event on thread
1882 EVENT_THREAD_EXIT(this);
1883
1884 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1885 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1886 // is deprecated anyhow.
1887 if (!is_Compiler_thread()) {
1888 int count = 3;
1889 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1890 EXCEPTION_MARK;
1891 JavaValue result(T_VOID);
1892 Klass* thread_klass = SystemDictionary::Thread_klass();
1893 JavaCalls::call_virtual(&result,
1894 threadObj, thread_klass,
1895 vmSymbols::exit_method_name(),
1896 vmSymbols::void_method_signature(),
1897 THREAD);
1898 CLEAR_PENDING_EXCEPTION;
1899 }
1900 }
1901 // notify JVMTI
1902 if (JvmtiExport::should_post_thread_life()) {
1903 JvmtiExport::post_thread_end(this);
1904 }
1905
1906 // We have notified the agents that we are exiting, before we go on,
1907 // we must check for a pending external suspend request and honor it
1908 // in order to not surprise the thread that made the suspend request.
1909 while (true) {
1910 {
1911 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1912 if (!is_external_suspend()) {
1913 set_terminated(_thread_exiting);
1914 ThreadService::current_thread_exiting(this);
1915 break;
1916 }
1917 // Implied else:
1918 // Things get a little tricky here. We have a pending external
1919 // suspend request, but we are holding the SR_lock so we
1920 // can't just self-suspend. So we temporarily drop the lock
1921 // and then self-suspend.
1922 }
1923
1924 ThreadBlockInVM tbivm(this);
1925 java_suspend_self();
1926
1927 // We're done with this suspend request, but we have to loop around
1928 // and check again. Eventually we will get SR_lock without a pending
1929 // external suspend request and will be able to mark ourselves as
1930 // exiting.
1931 }
1932 // no more external suspends are allowed at this point
1933 } else {
1934 // before_exit() has already posted JVMTI THREAD_END events
1935 }
1936
1937 if (log_is_enabled(Debug, os, thread, timer)) {
1938 _timer_exit_phase1.stop();
1939 _timer_exit_phase2.start();
1940 }
1941 // Notify waiters on thread object. This has to be done after exit() is called
1942 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1943 // group should have the destroyed bit set before waiters are notified).
1944 ensure_join(this);
1945 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1946
1947 if (log_is_enabled(Debug, os, thread, timer)) {
1948 _timer_exit_phase2.stop();
1949 _timer_exit_phase3.start();
1950 }
1951 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1952 // held by this thread must be released. The spec does not distinguish
1953 // between JNI-acquired and regular Java monitors. We can only see
1954 // regular Java monitors here if monitor enter-exit matching is broken.
1955 //
1956 // Optionally release any monitors for regular JavaThread exits. This
1957 // is provided as a work around for any bugs in monitor enter-exit
1958 // matching. This can be expensive so it is not enabled by default.
1959 //
1960 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1961 // ObjectSynchronizer::release_monitors_owned_by_thread().
1962 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
1963 // Sanity check even though JNI DetachCurrentThread() would have
1964 // returned JNI_ERR if there was a Java frame. JavaThread exit
1965 // should be done executing Java code by the time we get here.
1966 assert(!this->has_last_Java_frame(),
1967 "should not have a Java frame when detaching or exiting");
1968 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1969 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1970 }
1971
1972 // These things needs to be done while we are still a Java Thread. Make sure that thread
1973 // is in a consistent state, in case GC happens
1974 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1975
1976 if (active_handles() != NULL) {
1977 JNIHandleBlock* block = active_handles();
1978 set_active_handles(NULL);
1979 JNIHandleBlock::release_block(block);
1980 }
1981
1982 if (free_handle_block() != NULL) {
1983 JNIHandleBlock* block = free_handle_block();
1984 set_free_handle_block(NULL);
1985 JNIHandleBlock::release_block(block);
1986 }
1987
1988 // These have to be removed while this is still a valid thread.
1989 remove_stack_guard_pages();
1990
1991 if (UseTLAB) {
1992 tlab().make_parsable(true); // retire TLAB
1993 }
1994
1995 if (JvmtiEnv::environments_might_exist()) {
1996 JvmtiExport::cleanup_thread(this);
1997 }
1998
1999 // We must flush any deferred card marks and other various GC barrier
2000 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2001 // before removing a thread from the list of active threads.
2002 BarrierSet::barrier_set()->on_thread_detach(this);
2003
2004 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2005 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2006 os::current_thread_id());
2007
2008 if (log_is_enabled(Debug, os, thread, timer)) {
2009 _timer_exit_phase3.stop();
2010 _timer_exit_phase4.start();
2011 }
2012 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2013 Threads::remove(this);
2014
2015 if (log_is_enabled(Debug, os, thread, timer)) {
2016 _timer_exit_phase4.stop();
2017 ResourceMark rm(this);
2018 log_debug(os, thread, timer)("name='%s'"
2019 ", exit-phase1=" JLONG_FORMAT
2020 ", exit-phase2=" JLONG_FORMAT
2021 ", exit-phase3=" JLONG_FORMAT
2022 ", exit-phase4=" JLONG_FORMAT,
2023 get_thread_name(),
2024 _timer_exit_phase1.milliseconds(),
2025 _timer_exit_phase2.milliseconds(),
2026 _timer_exit_phase3.milliseconds(),
2027 _timer_exit_phase4.milliseconds());
2028 }
2029 }
2030
2031 void JavaThread::cleanup_failed_attach_current_thread() {
2032 if (active_handles() != NULL) {
2033 JNIHandleBlock* block = active_handles();
2034 set_active_handles(NULL);
2035 JNIHandleBlock::release_block(block);
2036 }
2037
2038 if (free_handle_block() != NULL) {
2039 JNIHandleBlock* block = free_handle_block();
2040 set_free_handle_block(NULL);
2041 JNIHandleBlock::release_block(block);
2042 }
2043
2044 // These have to be removed while this is still a valid thread.
2045 remove_stack_guard_pages();
2046
2047 if (UseTLAB) {
2048 tlab().make_parsable(true); // retire TLAB, if any
2049 }
2050
2051 BarrierSet::barrier_set()->on_thread_detach(this);
2052
2053 Threads::remove(this);
2054 this->smr_delete();
2055 }
2056
2057 JavaThread* JavaThread::active() {
2058 Thread* thread = Thread::current();
2059 if (thread->is_Java_thread()) {
2060 return (JavaThread*) thread;
2061 } else {
2062 assert(thread->is_VM_thread(), "this must be a vm thread");
2063 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2064 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2065 assert(ret->is_Java_thread(), "must be a Java thread");
2066 return ret;
2067 }
2068 }
2069
2070 bool JavaThread::is_lock_owned(address adr) const {
2071 if (Thread::is_lock_owned(adr)) return true;
2072
2073 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2074 if (chunk->contains(adr)) return true;
2075 }
2076
2077 return false;
2078 }
2079
2080
2081 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2082 chunk->set_next(monitor_chunks());
2083 set_monitor_chunks(chunk);
2084 }
2085
2086 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2087 guarantee(monitor_chunks() != NULL, "must be non empty");
2088 if (monitor_chunks() == chunk) {
2089 set_monitor_chunks(chunk->next());
2090 } else {
2091 MonitorChunk* prev = monitor_chunks();
2092 while (prev->next() != chunk) prev = prev->next();
2093 prev->set_next(chunk->next());
2094 }
2095 }
2096
2097 // JVM support.
2098
2099 // Note: this function shouldn't block if it's called in
2100 // _thread_in_native_trans state (such as from
2101 // check_special_condition_for_native_trans()).
2102 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2103
2104 if (has_last_Java_frame() && has_async_condition()) {
2105 // If we are at a polling page safepoint (not a poll return)
2106 // then we must defer async exception because live registers
2107 // will be clobbered by the exception path. Poll return is
2108 // ok because the call we a returning from already collides
2109 // with exception handling registers and so there is no issue.
2110 // (The exception handling path kills call result registers but
2111 // this is ok since the exception kills the result anyway).
2112
2113 if (is_at_poll_safepoint()) {
2114 // if the code we are returning to has deoptimized we must defer
2115 // the exception otherwise live registers get clobbered on the
2116 // exception path before deoptimization is able to retrieve them.
2117 //
2118 RegisterMap map(this, false);
2119 frame caller_fr = last_frame().sender(&map);
2120 assert(caller_fr.is_compiled_frame(), "what?");
2121 if (caller_fr.is_deoptimized_frame()) {
2122 log_info(exceptions)("deferred async exception at compiled safepoint");
2123 return;
2124 }
2125 }
2126 }
2127
2128 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2129 if (condition == _no_async_condition) {
2130 // Conditions have changed since has_special_runtime_exit_condition()
2131 // was called:
2132 // - if we were here only because of an external suspend request,
2133 // then that was taken care of above (or cancelled) so we are done
2134 // - if we were here because of another async request, then it has
2135 // been cleared between the has_special_runtime_exit_condition()
2136 // and now so again we are done
2137 return;
2138 }
2139
2140 // Check for pending async. exception
2141 if (_pending_async_exception != NULL) {
2142 // Only overwrite an already pending exception, if it is not a threadDeath.
2143 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2144
2145 // We cannot call Exceptions::_throw(...) here because we cannot block
2146 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2147
2148 LogTarget(Info, exceptions) lt;
2149 if (lt.is_enabled()) {
2150 ResourceMark rm;
2151 LogStream ls(lt);
2152 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2153 if (has_last_Java_frame()) {
2154 frame f = last_frame();
2155 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2156 }
2157 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2158 }
2159 _pending_async_exception = NULL;
2160 clear_has_async_exception();
2161 }
2162 }
2163
2164 if (check_unsafe_error &&
2165 condition == _async_unsafe_access_error && !has_pending_exception()) {
2166 condition = _no_async_condition; // done
2167 switch (thread_state()) {
2168 case _thread_in_vm: {
2169 JavaThread* THREAD = this;
2170 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2171 }
2172 case _thread_in_native: {
2173 ThreadInVMfromNative tiv(this);
2174 JavaThread* THREAD = this;
2175 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2176 }
2177 case _thread_in_Java: {
2178 ThreadInVMfromJava tiv(this);
2179 JavaThread* THREAD = this;
2180 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2181 }
2182 default:
2183 ShouldNotReachHere();
2184 }
2185 }
2186
2187 assert(condition == _no_async_condition || has_pending_exception() ||
2188 (!check_unsafe_error && condition == _async_unsafe_access_error),
2189 "must have handled the async condition, if no exception");
2190 }
2191
2192 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2193 //
2194 // Check for pending external suspend. Internal suspend requests do
2195 // not use handle_special_runtime_exit_condition().
2196 // If JNIEnv proxies are allowed, don't self-suspend if the target
2197 // thread is not the current thread. In older versions of jdbx, jdbx
2198 // threads could call into the VM with another thread's JNIEnv so we
2199 // can be here operating on behalf of a suspended thread (4432884).
2200 bool do_self_suspend = is_external_suspend_with_lock();
2201 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2202 //
2203 // Because thread is external suspended the safepoint code will count
2204 // thread as at a safepoint. This can be odd because we can be here
2205 // as _thread_in_Java which would normally transition to _thread_blocked
2206 // at a safepoint. We would like to mark the thread as _thread_blocked
2207 // before calling java_suspend_self like all other callers of it but
2208 // we must then observe proper safepoint protocol. (We can't leave
2209 // _thread_blocked with a safepoint in progress). However we can be
2210 // here as _thread_in_native_trans so we can't use a normal transition
2211 // constructor/destructor pair because they assert on that type of
2212 // transition. We could do something like:
2213 //
2214 // JavaThreadState state = thread_state();
2215 // set_thread_state(_thread_in_vm);
2216 // {
2217 // ThreadBlockInVM tbivm(this);
2218 // java_suspend_self()
2219 // }
2220 // set_thread_state(_thread_in_vm_trans);
2221 // if (safepoint) block;
2222 // set_thread_state(state);
2223 //
2224 // but that is pretty messy. Instead we just go with the way the
2225 // code has worked before and note that this is the only path to
2226 // java_suspend_self that doesn't put the thread in _thread_blocked
2227 // mode.
2228
2229 frame_anchor()->make_walkable(this);
2230 java_suspend_self();
2231
2232 // We might be here for reasons in addition to the self-suspend request
2233 // so check for other async requests.
2234 }
2235
2236 if (check_asyncs) {
2237 check_and_handle_async_exceptions();
2238 }
2239 #if INCLUDE_TRACE
2240 if (is_trace_suspend()) {
2241 TRACE_SUSPEND_THREAD(this);
2242 }
2243 #endif
2244 }
2245
2246 void JavaThread::send_thread_stop(oop java_throwable) {
2247 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2248 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2249 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2250
2251 // Do not throw asynchronous exceptions against the compiler thread
2252 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2253 if (!can_call_java()) return;
2254
2255 {
2256 // Actually throw the Throwable against the target Thread - however
2257 // only if there is no thread death exception installed already.
2258 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2259 // If the topmost frame is a runtime stub, then we are calling into
2260 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2261 // must deoptimize the caller before continuing, as the compiled exception handler table
2262 // may not be valid
2263 if (has_last_Java_frame()) {
2264 frame f = last_frame();
2265 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2266 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2267 RegisterMap reg_map(this, UseBiasedLocking);
2268 frame compiled_frame = f.sender(®_map);
2269 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2270 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2271 }
2272 }
2273 }
2274
2275 // Set async. pending exception in thread.
2276 set_pending_async_exception(java_throwable);
2277
2278 if (log_is_enabled(Info, exceptions)) {
2279 ResourceMark rm;
2280 log_info(exceptions)("Pending Async. exception installed of type: %s",
2281 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2282 }
2283 // for AbortVMOnException flag
2284 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2285 }
2286 }
2287
2288
2289 // Interrupt thread so it will wake up from a potential wait()
2290 Thread::interrupt(this);
2291 }
2292
2293 // External suspension mechanism.
2294 //
2295 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2296 // to any VM_locks and it is at a transition
2297 // Self-suspension will happen on the transition out of the vm.
2298 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2299 //
2300 // Guarantees on return:
2301 // + Target thread will not execute any new bytecode (that's why we need to
2302 // force a safepoint)
2303 // + Target thread will not enter any new monitors
2304 //
2305 void JavaThread::java_suspend() {
2306 ThreadsListHandle tlh;
2307 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2308 return;
2309 }
2310
2311 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2312 if (!is_external_suspend()) {
2313 // a racing resume has cancelled us; bail out now
2314 return;
2315 }
2316
2317 // suspend is done
2318 uint32_t debug_bits = 0;
2319 // Warning: is_ext_suspend_completed() may temporarily drop the
2320 // SR_lock to allow the thread to reach a stable thread state if
2321 // it is currently in a transient thread state.
2322 if (is_ext_suspend_completed(false /* !called_by_wait */,
2323 SuspendRetryDelay, &debug_bits)) {
2324 return;
2325 }
2326 }
2327
2328 VM_ThreadSuspend vm_suspend;
2329 VMThread::execute(&vm_suspend);
2330 }
2331
2332 // Part II of external suspension.
2333 // A JavaThread self suspends when it detects a pending external suspend
2334 // request. This is usually on transitions. It is also done in places
2335 // where continuing to the next transition would surprise the caller,
2336 // e.g., monitor entry.
2337 //
2338 // Returns the number of times that the thread self-suspended.
2339 //
2340 // Note: DO NOT call java_suspend_self() when you just want to block current
2341 // thread. java_suspend_self() is the second stage of cooperative
2342 // suspension for external suspend requests and should only be used
2343 // to complete an external suspend request.
2344 //
2345 int JavaThread::java_suspend_self() {
2346 int ret = 0;
2347
2348 // we are in the process of exiting so don't suspend
2349 if (is_exiting()) {
2350 clear_external_suspend();
2351 return ret;
2352 }
2353
2354 assert(_anchor.walkable() ||
2355 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2356 "must have walkable stack");
2357
2358 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2359
2360 assert(!this->is_ext_suspended(),
2361 "a thread trying to self-suspend should not already be suspended");
2362
2363 if (this->is_suspend_equivalent()) {
2364 // If we are self-suspending as a result of the lifting of a
2365 // suspend equivalent condition, then the suspend_equivalent
2366 // flag is not cleared until we set the ext_suspended flag so
2367 // that wait_for_ext_suspend_completion() returns consistent
2368 // results.
2369 this->clear_suspend_equivalent();
2370 }
2371
2372 // A racing resume may have cancelled us before we grabbed SR_lock
2373 // above. Or another external suspend request could be waiting for us
2374 // by the time we return from SR_lock()->wait(). The thread
2375 // that requested the suspension may already be trying to walk our
2376 // stack and if we return now, we can change the stack out from under
2377 // it. This would be a "bad thing (TM)" and cause the stack walker
2378 // to crash. We stay self-suspended until there are no more pending
2379 // external suspend requests.
2380 while (is_external_suspend()) {
2381 ret++;
2382 this->set_ext_suspended();
2383
2384 // _ext_suspended flag is cleared by java_resume()
2385 while (is_ext_suspended()) {
2386 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2387 }
2388 }
2389
2390 return ret;
2391 }
2392
2393 #ifdef ASSERT
2394 // verify the JavaThread has not yet been published in the Threads::list, and
2395 // hence doesn't need protection from concurrent access at this stage
2396 void JavaThread::verify_not_published() {
2397 ThreadsListHandle tlh;
2398 assert(!tlh.includes(this), "JavaThread shouldn't have been published yet!");
2399 }
2400 #endif
2401
2402 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2403 // progress or when _suspend_flags is non-zero.
2404 // Current thread needs to self-suspend if there is a suspend request and/or
2405 // block if a safepoint is in progress.
2406 // Async exception ISN'T checked.
2407 // Note only the ThreadInVMfromNative transition can call this function
2408 // directly and when thread state is _thread_in_native_trans
2409 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2410 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2411
2412 JavaThread *curJT = JavaThread::current();
2413 bool do_self_suspend = thread->is_external_suspend();
2414
2415 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2416
2417 // If JNIEnv proxies are allowed, don't self-suspend if the target
2418 // thread is not the current thread. In older versions of jdbx, jdbx
2419 // threads could call into the VM with another thread's JNIEnv so we
2420 // can be here operating on behalf of a suspended thread (4432884).
2421 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2422 JavaThreadState state = thread->thread_state();
2423
2424 // We mark this thread_blocked state as a suspend-equivalent so
2425 // that a caller to is_ext_suspend_completed() won't be confused.
2426 // The suspend-equivalent state is cleared by java_suspend_self().
2427 thread->set_suspend_equivalent();
2428
2429 // If the safepoint code sees the _thread_in_native_trans state, it will
2430 // wait until the thread changes to other thread state. There is no
2431 // guarantee on how soon we can obtain the SR_lock and complete the
2432 // self-suspend request. It would be a bad idea to let safepoint wait for
2433 // too long. Temporarily change the state to _thread_blocked to
2434 // let the VM thread know that this thread is ready for GC. The problem
2435 // of changing thread state is that safepoint could happen just after
2436 // java_suspend_self() returns after being resumed, and VM thread will
2437 // see the _thread_blocked state. We must check for safepoint
2438 // after restoring the state and make sure we won't leave while a safepoint
2439 // is in progress.
2440 thread->set_thread_state(_thread_blocked);
2441 thread->java_suspend_self();
2442 thread->set_thread_state(state);
2443
2444 InterfaceSupport::serialize_thread_state_with_handler(thread);
2445 }
2446
2447 SafepointMechanism::block_if_requested(curJT);
2448
2449 if (thread->is_deopt_suspend()) {
2450 thread->clear_deopt_suspend();
2451 RegisterMap map(thread, false);
2452 frame f = thread->last_frame();
2453 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2454 f = f.sender(&map);
2455 }
2456 if (f.id() == thread->must_deopt_id()) {
2457 thread->clear_must_deopt_id();
2458 f.deoptimize(thread);
2459 } else {
2460 fatal("missed deoptimization!");
2461 }
2462 }
2463 #if INCLUDE_TRACE
2464 if (thread->is_trace_suspend()) {
2465 TRACE_SUSPEND_THREAD(thread);
2466 }
2467 #endif
2468 }
2469
2470 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2471 // progress or when _suspend_flags is non-zero.
2472 // Current thread needs to self-suspend if there is a suspend request and/or
2473 // block if a safepoint is in progress.
2474 // Also check for pending async exception (not including unsafe access error).
2475 // Note only the native==>VM/Java barriers can call this function and when
2476 // thread state is _thread_in_native_trans.
2477 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2478 check_safepoint_and_suspend_for_native_trans(thread);
2479
2480 if (thread->has_async_exception()) {
2481 // We are in _thread_in_native_trans state, don't handle unsafe
2482 // access error since that may block.
2483 thread->check_and_handle_async_exceptions(false);
2484 }
2485 }
2486
2487 // This is a variant of the normal
2488 // check_special_condition_for_native_trans with slightly different
2489 // semantics for use by critical native wrappers. It does all the
2490 // normal checks but also performs the transition back into
2491 // thread_in_Java state. This is required so that critical natives
2492 // can potentially block and perform a GC if they are the last thread
2493 // exiting the GCLocker.
2494 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2495 check_special_condition_for_native_trans(thread);
2496
2497 // Finish the transition
2498 thread->set_thread_state(_thread_in_Java);
2499
2500 if (thread->do_critical_native_unlock()) {
2501 ThreadInVMfromJavaNoAsyncException tiv(thread);
2502 GCLocker::unlock_critical(thread);
2503 thread->clear_critical_native_unlock();
2504 }
2505 }
2506
2507 // We need to guarantee the Threads_lock here, since resumes are not
2508 // allowed during safepoint synchronization
2509 // Can only resume from an external suspension
2510 void JavaThread::java_resume() {
2511 assert_locked_or_safepoint(Threads_lock);
2512
2513 // Sanity check: thread is gone, has started exiting or the thread
2514 // was not externally suspended.
2515 ThreadsListHandle tlh;
2516 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2517 return;
2518 }
2519
2520 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2521
2522 clear_external_suspend();
2523
2524 if (is_ext_suspended()) {
2525 clear_ext_suspended();
2526 SR_lock()->notify_all();
2527 }
2528 }
2529
2530 size_t JavaThread::_stack_red_zone_size = 0;
2531 size_t JavaThread::_stack_yellow_zone_size = 0;
2532 size_t JavaThread::_stack_reserved_zone_size = 0;
2533 size_t JavaThread::_stack_shadow_zone_size = 0;
2534
2535 void JavaThread::create_stack_guard_pages() {
2536 if (!os::uses_stack_guard_pages() ||
2537 _stack_guard_state != stack_guard_unused ||
2538 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2539 log_info(os, thread)("Stack guard page creation for thread "
2540 UINTX_FORMAT " disabled", os::current_thread_id());
2541 return;
2542 }
2543 address low_addr = stack_end();
2544 size_t len = stack_guard_zone_size();
2545
2546 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2547 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2548
2549 int must_commit = os::must_commit_stack_guard_pages();
2550 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2551
2552 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2553 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2554 return;
2555 }
2556
2557 if (os::guard_memory((char *) low_addr, len)) {
2558 _stack_guard_state = stack_guard_enabled;
2559 } else {
2560 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2561 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2562 if (os::uncommit_memory((char *) low_addr, len)) {
2563 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2564 }
2565 return;
2566 }
2567
2568 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2569 PTR_FORMAT "-" PTR_FORMAT ".",
2570 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2571 }
2572
2573 void JavaThread::remove_stack_guard_pages() {
2574 assert(Thread::current() == this, "from different thread");
2575 if (_stack_guard_state == stack_guard_unused) return;
2576 address low_addr = stack_end();
2577 size_t len = stack_guard_zone_size();
2578
2579 if (os::must_commit_stack_guard_pages()) {
2580 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2581 _stack_guard_state = stack_guard_unused;
2582 } else {
2583 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2584 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2585 return;
2586 }
2587 } else {
2588 if (_stack_guard_state == stack_guard_unused) return;
2589 if (os::unguard_memory((char *) low_addr, len)) {
2590 _stack_guard_state = stack_guard_unused;
2591 } else {
2592 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2593 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2594 return;
2595 }
2596 }
2597
2598 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2599 PTR_FORMAT "-" PTR_FORMAT ".",
2600 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2601 }
2602
2603 void JavaThread::enable_stack_reserved_zone() {
2604 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2605 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2606
2607 // The base notation is from the stack's point of view, growing downward.
2608 // We need to adjust it to work correctly with guard_memory()
2609 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2610
2611 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2612 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2613
2614 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2615 _stack_guard_state = stack_guard_enabled;
2616 } else {
2617 warning("Attempt to guard stack reserved zone failed.");
2618 }
2619 enable_register_stack_guard();
2620 }
2621
2622 void JavaThread::disable_stack_reserved_zone() {
2623 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2624 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled");
2625
2626 // Simply return if called for a thread that does not use guard pages.
2627 if (_stack_guard_state == stack_guard_unused) return;
2628
2629 // The base notation is from the stack's point of view, growing downward.
2630 // We need to adjust it to work correctly with guard_memory()
2631 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2632
2633 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2634 _stack_guard_state = stack_guard_reserved_disabled;
2635 } else {
2636 warning("Attempt to unguard stack reserved zone failed.");
2637 }
2638 disable_register_stack_guard();
2639 }
2640
2641 void JavaThread::enable_stack_yellow_reserved_zone() {
2642 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2643 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2644
2645 // The base notation is from the stacks point of view, growing downward.
2646 // We need to adjust it to work correctly with guard_memory()
2647 address base = stack_red_zone_base();
2648
2649 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2650 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2651
2652 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2653 _stack_guard_state = stack_guard_enabled;
2654 } else {
2655 warning("Attempt to guard stack yellow zone failed.");
2656 }
2657 enable_register_stack_guard();
2658 }
2659
2660 void JavaThread::disable_stack_yellow_reserved_zone() {
2661 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2662 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2663
2664 // Simply return if called for a thread that does not use guard pages.
2665 if (_stack_guard_state == stack_guard_unused) return;
2666
2667 // The base notation is from the stacks point of view, growing downward.
2668 // We need to adjust it to work correctly with guard_memory()
2669 address base = stack_red_zone_base();
2670
2671 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2672 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2673 } else {
2674 warning("Attempt to unguard stack yellow zone failed.");
2675 }
2676 disable_register_stack_guard();
2677 }
2678
2679 void JavaThread::enable_stack_red_zone() {
2680 // The base notation is from the stacks point of view, growing downward.
2681 // We need to adjust it to work correctly with guard_memory()
2682 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2683 address base = stack_red_zone_base() - stack_red_zone_size();
2684
2685 guarantee(base < stack_base(), "Error calculating stack red zone");
2686 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2687
2688 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2689 warning("Attempt to guard stack red zone failed.");
2690 }
2691 }
2692
2693 void JavaThread::disable_stack_red_zone() {
2694 // The base notation is from the stacks point of view, growing downward.
2695 // We need to adjust it to work correctly with guard_memory()
2696 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2697 address base = stack_red_zone_base() - stack_red_zone_size();
2698 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2699 warning("Attempt to unguard stack red zone failed.");
2700 }
2701 }
2702
2703 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2704 // ignore is there is no stack
2705 if (!has_last_Java_frame()) return;
2706 // traverse the stack frames. Starts from top frame.
2707 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2708 frame* fr = fst.current();
2709 f(fr, fst.register_map());
2710 }
2711 }
2712
2713
2714 #ifndef PRODUCT
2715 // Deoptimization
2716 // Function for testing deoptimization
2717 void JavaThread::deoptimize() {
2718 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2719 StackFrameStream fst(this, UseBiasedLocking);
2720 bool deopt = false; // Dump stack only if a deopt actually happens.
2721 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2722 // Iterate over all frames in the thread and deoptimize
2723 for (; !fst.is_done(); fst.next()) {
2724 if (fst.current()->can_be_deoptimized()) {
2725
2726 if (only_at) {
2727 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2728 // consists of comma or carriage return separated numbers so
2729 // search for the current bci in that string.
2730 address pc = fst.current()->pc();
2731 nmethod* nm = (nmethod*) fst.current()->cb();
2732 ScopeDesc* sd = nm->scope_desc_at(pc);
2733 char buffer[8];
2734 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2735 size_t len = strlen(buffer);
2736 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2737 while (found != NULL) {
2738 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2739 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2740 // Check that the bci found is bracketed by terminators.
2741 break;
2742 }
2743 found = strstr(found + 1, buffer);
2744 }
2745 if (!found) {
2746 continue;
2747 }
2748 }
2749
2750 if (DebugDeoptimization && !deopt) {
2751 deopt = true; // One-time only print before deopt
2752 tty->print_cr("[BEFORE Deoptimization]");
2753 trace_frames();
2754 trace_stack();
2755 }
2756 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2757 }
2758 }
2759
2760 if (DebugDeoptimization && deopt) {
2761 tty->print_cr("[AFTER Deoptimization]");
2762 trace_frames();
2763 }
2764 }
2765
2766
2767 // Make zombies
2768 void JavaThread::make_zombies() {
2769 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2770 if (fst.current()->can_be_deoptimized()) {
2771 // it is a Java nmethod
2772 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2773 nm->make_not_entrant();
2774 }
2775 }
2776 }
2777 #endif // PRODUCT
2778
2779
2780 void JavaThread::deoptimized_wrt_marked_nmethods() {
2781 if (!has_last_Java_frame()) return;
2782 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2783 StackFrameStream fst(this, UseBiasedLocking);
2784 for (; !fst.is_done(); fst.next()) {
2785 if (fst.current()->should_be_deoptimized()) {
2786 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2787 }
2788 }
2789 }
2790
2791
2792 // If the caller is a NamedThread, then remember, in the current scope,
2793 // the given JavaThread in its _processed_thread field.
2794 class RememberProcessedThread: public StackObj {
2795 NamedThread* _cur_thr;
2796 public:
2797 RememberProcessedThread(JavaThread* jthr) {
2798 Thread* thread = Thread::current();
2799 if (thread->is_Named_thread()) {
2800 _cur_thr = (NamedThread *)thread;
2801 _cur_thr->set_processed_thread(jthr);
2802 } else {
2803 _cur_thr = NULL;
2804 }
2805 }
2806
2807 ~RememberProcessedThread() {
2808 if (_cur_thr) {
2809 _cur_thr->set_processed_thread(NULL);
2810 }
2811 }
2812 };
2813
2814 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2815 // Verify that the deferred card marks have been flushed.
2816 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2817
2818 // Traverse the GCHandles
2819 Thread::oops_do(f, cf);
2820
2821 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2822
2823 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2824 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2825
2826 if (has_last_Java_frame()) {
2827 // Record JavaThread to GC thread
2828 RememberProcessedThread rpt(this);
2829
2830 // Traverse the privileged stack
2831 if (_privileged_stack_top != NULL) {
2832 _privileged_stack_top->oops_do(f);
2833 }
2834
2835 // traverse the registered growable array
2836 if (_array_for_gc != NULL) {
2837 for (int index = 0; index < _array_for_gc->length(); index++) {
2838 f->do_oop(_array_for_gc->adr_at(index));
2839 }
2840 }
2841
2842 // Traverse the monitor chunks
2843 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2844 chunk->oops_do(f);
2845 }
2846
2847 // Traverse the execution stack
2848 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2849 fst.current()->oops_do(f, cf, fst.register_map());
2850 }
2851 }
2852
2853 // callee_target is never live across a gc point so NULL it here should
2854 // it still contain a methdOop.
2855
2856 set_callee_target(NULL);
2857
2858 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2859 // If we have deferred set_locals there might be oops waiting to be
2860 // written
2861 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2862 if (list != NULL) {
2863 for (int i = 0; i < list->length(); i++) {
2864 list->at(i)->oops_do(f);
2865 }
2866 }
2867
2868 // Traverse instance variables at the end since the GC may be moving things
2869 // around using this function
2870 f->do_oop((oop*) &_threadObj);
2871 f->do_oop((oop*) &_vm_result);
2872 f->do_oop((oop*) &_exception_oop);
2873 f->do_oop((oop*) &_pending_async_exception);
2874
2875 if (jvmti_thread_state() != NULL) {
2876 jvmti_thread_state()->oops_do(f);
2877 }
2878 }
2879
2880 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2881 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2882 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2883
2884 if (has_last_Java_frame()) {
2885 // Traverse the execution stack
2886 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2887 fst.current()->nmethods_do(cf);
2888 }
2889 }
2890 }
2891
2892 void JavaThread::metadata_do(void f(Metadata*)) {
2893 if (has_last_Java_frame()) {
2894 // Traverse the execution stack to call f() on the methods in the stack
2895 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2896 fst.current()->metadata_do(f);
2897 }
2898 } else if (is_Compiler_thread()) {
2899 // need to walk ciMetadata in current compile tasks to keep alive.
2900 CompilerThread* ct = (CompilerThread*)this;
2901 if (ct->env() != NULL) {
2902 ct->env()->metadata_do(f);
2903 }
2904 CompileTask* task = ct->task();
2905 if (task != NULL) {
2906 task->metadata_do(f);
2907 }
2908 }
2909 }
2910
2911 // Printing
2912 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2913 switch (_thread_state) {
2914 case _thread_uninitialized: return "_thread_uninitialized";
2915 case _thread_new: return "_thread_new";
2916 case _thread_new_trans: return "_thread_new_trans";
2917 case _thread_in_native: return "_thread_in_native";
2918 case _thread_in_native_trans: return "_thread_in_native_trans";
2919 case _thread_in_vm: return "_thread_in_vm";
2920 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2921 case _thread_in_Java: return "_thread_in_Java";
2922 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2923 case _thread_blocked: return "_thread_blocked";
2924 case _thread_blocked_trans: return "_thread_blocked_trans";
2925 default: return "unknown thread state";
2926 }
2927 }
2928
2929 #ifndef PRODUCT
2930 void JavaThread::print_thread_state_on(outputStream *st) const {
2931 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2932 };
2933 void JavaThread::print_thread_state() const {
2934 print_thread_state_on(tty);
2935 }
2936 #endif // PRODUCT
2937
2938 // Called by Threads::print() for VM_PrintThreads operation
2939 void JavaThread::print_on(outputStream *st) const {
2940 st->print_raw("\"");
2941 st->print_raw(get_thread_name());
2942 st->print_raw("\" ");
2943 oop thread_oop = threadObj();
2944 if (thread_oop != NULL) {
2945 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
2946 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2947 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2948 }
2949 Thread::print_on(st);
2950 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2951 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2952 if (thread_oop != NULL) {
2953 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2954 }
2955 #ifndef PRODUCT
2956 print_thread_state_on(st);
2957 _safepoint_state->print_on(st);
2958 #endif // PRODUCT
2959 if (is_Compiler_thread()) {
2960 CompileTask *task = ((CompilerThread*)this)->task();
2961 if (task != NULL) {
2962 st->print(" Compiling: ");
2963 task->print(st, NULL, true, false);
2964 } else {
2965 st->print(" No compile task");
2966 }
2967 st->cr();
2968 }
2969 }
2970
2971 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
2972 st->print("%s", get_thread_name_string(buf, buflen));
2973 }
2974
2975 // Called by fatal error handler. The difference between this and
2976 // JavaThread::print() is that we can't grab lock or allocate memory.
2977 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2978 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2979 oop thread_obj = threadObj();
2980 if (thread_obj != NULL) {
2981 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2982 }
2983 st->print(" [");
2984 st->print("%s", _get_thread_state_name(_thread_state));
2985 if (osthread()) {
2986 st->print(", id=%d", osthread()->thread_id());
2987 }
2988 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2989 p2i(stack_end()), p2i(stack_base()));
2990 st->print("]");
2991
2992 if (_threads_hazard_ptr != NULL) {
2993 st->print(" _threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
2994 }
2995 if (_nested_threads_hazard_ptr != NULL) {
2996 print_nested_threads_hazard_ptrs_on(st);
2997 }
2998 return;
2999 }
3000
3001 // Verification
3002
3003 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3004
3005 void JavaThread::verify() {
3006 // Verify oops in the thread.
3007 oops_do(&VerifyOopClosure::verify_oop, NULL);
3008
3009 // Verify the stack frames.
3010 frames_do(frame_verify);
3011 }
3012
3013 // CR 6300358 (sub-CR 2137150)
3014 // Most callers of this method assume that it can't return NULL but a
3015 // thread may not have a name whilst it is in the process of attaching to
3016 // the VM - see CR 6412693, and there are places where a JavaThread can be
3017 // seen prior to having it's threadObj set (eg JNI attaching threads and
3018 // if vm exit occurs during initialization). These cases can all be accounted
3019 // for such that this method never returns NULL.
3020 const char* JavaThread::get_thread_name() const {
3021 #ifdef ASSERT
3022 // early safepoints can hit while current thread does not yet have TLS
3023 if (!SafepointSynchronize::is_at_safepoint()) {
3024 Thread *cur = Thread::current();
3025 if (!(cur->is_Java_thread() && cur == this)) {
3026 // Current JavaThreads are allowed to get their own name without
3027 // the Threads_lock.
3028 assert_locked_or_safepoint(Threads_lock);
3029 }
3030 }
3031 #endif // ASSERT
3032 return get_thread_name_string();
3033 }
3034
3035 // Returns a non-NULL representation of this thread's name, or a suitable
3036 // descriptive string if there is no set name
3037 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3038 const char* name_str;
3039 oop thread_obj = threadObj();
3040 if (thread_obj != NULL) {
3041 oop name = java_lang_Thread::name(thread_obj);
3042 if (name != NULL) {
3043 if (buf == NULL) {
3044 name_str = java_lang_String::as_utf8_string(name);
3045 } else {
3046 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3047 }
3048 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3049 name_str = "<no-name - thread is attaching>";
3050 } else {
3051 name_str = Thread::name();
3052 }
3053 } else {
3054 name_str = Thread::name();
3055 }
3056 assert(name_str != NULL, "unexpected NULL thread name");
3057 return name_str;
3058 }
3059
3060
3061 const char* JavaThread::get_threadgroup_name() const {
3062 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3063 oop thread_obj = threadObj();
3064 if (thread_obj != NULL) {
3065 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3066 if (thread_group != NULL) {
3067 // ThreadGroup.name can be null
3068 return java_lang_ThreadGroup::name(thread_group);
3069 }
3070 }
3071 return NULL;
3072 }
3073
3074 const char* JavaThread::get_parent_name() const {
3075 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3076 oop thread_obj = threadObj();
3077 if (thread_obj != NULL) {
3078 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3079 if (thread_group != NULL) {
3080 oop parent = java_lang_ThreadGroup::parent(thread_group);
3081 if (parent != NULL) {
3082 // ThreadGroup.name can be null
3083 return java_lang_ThreadGroup::name(parent);
3084 }
3085 }
3086 }
3087 return NULL;
3088 }
3089
3090 ThreadPriority JavaThread::java_priority() const {
3091 oop thr_oop = threadObj();
3092 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3093 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3094 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3095 return priority;
3096 }
3097
3098 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3099
3100 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3101 // Link Java Thread object <-> C++ Thread
3102
3103 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3104 // and put it into a new Handle. The Handle "thread_oop" can then
3105 // be used to pass the C++ thread object to other methods.
3106
3107 // Set the Java level thread object (jthread) field of the
3108 // new thread (a JavaThread *) to C++ thread object using the
3109 // "thread_oop" handle.
3110
3111 // Set the thread field (a JavaThread *) of the
3112 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3113
3114 Handle thread_oop(Thread::current(),
3115 JNIHandles::resolve_non_null(jni_thread));
3116 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3117 "must be initialized");
3118 set_threadObj(thread_oop());
3119 java_lang_Thread::set_thread(thread_oop(), this);
3120
3121 if (prio == NoPriority) {
3122 prio = java_lang_Thread::priority(thread_oop());
3123 assert(prio != NoPriority, "A valid priority should be present");
3124 }
3125
3126 // Push the Java priority down to the native thread; needs Threads_lock
3127 Thread::set_priority(this, prio);
3128
3129 // Add the new thread to the Threads list and set it in motion.
3130 // We must have threads lock in order to call Threads::add.
3131 // It is crucial that we do not block before the thread is
3132 // added to the Threads list for if a GC happens, then the java_thread oop
3133 // will not be visited by GC.
3134 Threads::add(this);
3135 }
3136
3137 oop JavaThread::current_park_blocker() {
3138 // Support for JSR-166 locks
3139 oop thread_oop = threadObj();
3140 if (thread_oop != NULL &&
3141 JDK_Version::current().supports_thread_park_blocker()) {
3142 return java_lang_Thread::park_blocker(thread_oop);
3143 }
3144 return NULL;
3145 }
3146
3147
3148 void JavaThread::print_stack_on(outputStream* st) {
3149 if (!has_last_Java_frame()) return;
3150 ResourceMark rm;
3151 HandleMark hm;
3152
3153 RegisterMap reg_map(this);
3154 vframe* start_vf = last_java_vframe(®_map);
3155 int count = 0;
3156 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3157 if (f->is_java_frame()) {
3158 javaVFrame* jvf = javaVFrame::cast(f);
3159 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3160
3161 // Print out lock information
3162 if (JavaMonitorsInStackTrace) {
3163 jvf->print_lock_info_on(st, count);
3164 }
3165 } else {
3166 // Ignore non-Java frames
3167 }
3168
3169 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3170 count++;
3171 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3172 }
3173 }
3174
3175
3176 // JVMTI PopFrame support
3177 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3178 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3179 if (in_bytes(size_in_bytes) != 0) {
3180 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3181 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3182 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3183 }
3184 }
3185
3186 void* JavaThread::popframe_preserved_args() {
3187 return _popframe_preserved_args;
3188 }
3189
3190 ByteSize JavaThread::popframe_preserved_args_size() {
3191 return in_ByteSize(_popframe_preserved_args_size);
3192 }
3193
3194 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3195 int sz = in_bytes(popframe_preserved_args_size());
3196 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3197 return in_WordSize(sz / wordSize);
3198 }
3199
3200 void JavaThread::popframe_free_preserved_args() {
3201 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3202 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3203 _popframe_preserved_args = NULL;
3204 _popframe_preserved_args_size = 0;
3205 }
3206
3207 #ifndef PRODUCT
3208
3209 void JavaThread::trace_frames() {
3210 tty->print_cr("[Describe stack]");
3211 int frame_no = 1;
3212 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3213 tty->print(" %d. ", frame_no++);
3214 fst.current()->print_value_on(tty, this);
3215 tty->cr();
3216 }
3217 }
3218
3219 class PrintAndVerifyOopClosure: public OopClosure {
3220 protected:
3221 template <class T> inline void do_oop_work(T* p) {
3222 oop obj = oopDesc::load_decode_heap_oop(p);
3223 if (obj == NULL) return;
3224 tty->print(INTPTR_FORMAT ": ", p2i(p));
3225 if (oopDesc::is_oop_or_null(obj)) {
3226 if (obj->is_objArray()) {
3227 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3228 } else {
3229 obj->print();
3230 }
3231 } else {
3232 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3233 }
3234 tty->cr();
3235 }
3236 public:
3237 virtual void do_oop(oop* p) { do_oop_work(p); }
3238 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3239 };
3240
3241
3242 static void oops_print(frame* f, const RegisterMap *map) {
3243 PrintAndVerifyOopClosure print;
3244 f->print_value();
3245 f->oops_do(&print, NULL, (RegisterMap*)map);
3246 }
3247
3248 // Print our all the locations that contain oops and whether they are
3249 // valid or not. This useful when trying to find the oldest frame
3250 // where an oop has gone bad since the frame walk is from youngest to
3251 // oldest.
3252 void JavaThread::trace_oops() {
3253 tty->print_cr("[Trace oops]");
3254 frames_do(oops_print);
3255 }
3256
3257
3258 #ifdef ASSERT
3259 // Print or validate the layout of stack frames
3260 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3261 ResourceMark rm;
3262 PRESERVE_EXCEPTION_MARK;
3263 FrameValues values;
3264 int frame_no = 0;
3265 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3266 fst.current()->describe(values, ++frame_no);
3267 if (depth == frame_no) break;
3268 }
3269 if (validate_only) {
3270 values.validate();
3271 } else {
3272 tty->print_cr("[Describe stack layout]");
3273 values.print(this);
3274 }
3275 }
3276 #endif
3277
3278 void JavaThread::trace_stack_from(vframe* start_vf) {
3279 ResourceMark rm;
3280 int vframe_no = 1;
3281 for (vframe* f = start_vf; f; f = f->sender()) {
3282 if (f->is_java_frame()) {
3283 javaVFrame::cast(f)->print_activation(vframe_no++);
3284 } else {
3285 f->print();
3286 }
3287 if (vframe_no > StackPrintLimit) {
3288 tty->print_cr("...<more frames>...");
3289 return;
3290 }
3291 }
3292 }
3293
3294
3295 void JavaThread::trace_stack() {
3296 if (!has_last_Java_frame()) return;
3297 ResourceMark rm;
3298 HandleMark hm;
3299 RegisterMap reg_map(this);
3300 trace_stack_from(last_java_vframe(®_map));
3301 }
3302
3303
3304 #endif // PRODUCT
3305
3306
3307 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3308 assert(reg_map != NULL, "a map must be given");
3309 frame f = last_frame();
3310 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3311 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3312 }
3313 return NULL;
3314 }
3315
3316
3317 Klass* JavaThread::security_get_caller_class(int depth) {
3318 vframeStream vfst(this);
3319 vfst.security_get_caller_frame(depth);
3320 if (!vfst.at_end()) {
3321 return vfst.method()->method_holder();
3322 }
3323 return NULL;
3324 }
3325
3326 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3327 assert(thread->is_Compiler_thread(), "must be compiler thread");
3328 CompileBroker::compiler_thread_loop();
3329 }
3330
3331 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3332 NMethodSweeper::sweeper_loop();
3333 }
3334
3335 // Create a CompilerThread
3336 CompilerThread::CompilerThread(CompileQueue* queue,
3337 CompilerCounters* counters)
3338 : JavaThread(&compiler_thread_entry) {
3339 _env = NULL;
3340 _log = NULL;
3341 _task = NULL;
3342 _queue = queue;
3343 _counters = counters;
3344 _buffer_blob = NULL;
3345 _compiler = NULL;
3346
3347 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3348 resource_area()->bias_to(mtCompiler);
3349
3350 #ifndef PRODUCT
3351 _ideal_graph_printer = NULL;
3352 #endif
3353 }
3354
3355 bool CompilerThread::can_call_java() const {
3356 return _compiler != NULL && _compiler->is_jvmci();
3357 }
3358
3359 // Create sweeper thread
3360 CodeCacheSweeperThread::CodeCacheSweeperThread()
3361 : JavaThread(&sweeper_thread_entry) {
3362 _scanned_compiled_method = NULL;
3363 }
3364
3365 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3366 JavaThread::oops_do(f, cf);
3367 if (_scanned_compiled_method != NULL && cf != NULL) {
3368 // Safepoints can occur when the sweeper is scanning an nmethod so
3369 // process it here to make sure it isn't unloaded in the middle of
3370 // a scan.
3371 cf->do_code_blob(_scanned_compiled_method);
3372 }
3373 }
3374
3375 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3376 JavaThread::nmethods_do(cf);
3377 if (_scanned_compiled_method != NULL && cf != NULL) {
3378 // Safepoints can occur when the sweeper is scanning an nmethod so
3379 // process it here to make sure it isn't unloaded in the middle of
3380 // a scan.
3381 cf->do_code_blob(_scanned_compiled_method);
3382 }
3383 }
3384
3385
3386 // ======= Threads ========
3387
3388 // The Threads class links together all active threads, and provides
3389 // operations over all threads. It is protected by the Threads_lock,
3390 // which is also used in other global contexts like safepointing.
3391 // ThreadsListHandles are used to safely perform operations on one
3392 // or more threads without the risk of the thread exiting during the
3393 // operation.
3394 //
3395 // Note: The Threads_lock is currently more widely used than we
3396 // would like. We are actively migrating Threads_lock uses to other
3397 // mechanisms in order to reduce Threads_lock contention.
3398
3399 JavaThread* Threads::_thread_list = NULL;
3400 int Threads::_number_of_threads = 0;
3401 int Threads::_number_of_non_daemon_threads = 0;
3402 int Threads::_return_code = 0;
3403 int Threads::_thread_claim_parity = 0;
3404 size_t JavaThread::_stack_size_at_create = 0;
3405
3406 #ifdef ASSERT
3407 bool Threads::_vm_complete = false;
3408 #endif
3409
3410 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3411 Prefetch::read((void*)addr, prefetch_interval);
3412 return *addr;
3413 }
3414
3415 // Possibly the ugliest for loop the world has seen. C++ does not allow
3416 // multiple types in the declaration section of the for loop. In this case
3417 // we are only dealing with pointers and hence can cast them. It looks ugly
3418 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3419 #define DO_JAVA_THREADS(LIST, X) \
3420 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3421 *MACRO_list = (JavaThread*)(LIST), \
3422 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3423 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3424 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3425 MACRO_current_p != MACRO_end; \
3426 MACRO_current_p++, \
3427 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3428
3429 // All JavaThreads
3430 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3431
3432 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3433 void Threads::threads_do(ThreadClosure* tc) {
3434 assert_locked_or_safepoint(Threads_lock);
3435 // ALL_JAVA_THREADS iterates through all JavaThreads
3436 ALL_JAVA_THREADS(p) {
3437 tc->do_thread(p);
3438 }
3439 // Someday we could have a table or list of all non-JavaThreads.
3440 // For now, just manually iterate through them.
3441 tc->do_thread(VMThread::vm_thread());
3442 Universe::heap()->gc_threads_do(tc);
3443 WatcherThread *wt = WatcherThread::watcher_thread();
3444 // Strictly speaking, the following NULL check isn't sufficient to make sure
3445 // the data for WatcherThread is still valid upon being examined. However,
3446 // considering that WatchThread terminates when the VM is on the way to
3447 // exit at safepoint, the chance of the above is extremely small. The right
3448 // way to prevent termination of WatcherThread would be to acquire
3449 // Terminator_lock, but we can't do that without violating the lock rank
3450 // checking in some cases.
3451 if (wt != NULL) {
3452 tc->do_thread(wt);
3453 }
3454
3455 // If CompilerThreads ever become non-JavaThreads, add them here
3456 }
3457
3458 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3459 int cp = Threads::thread_claim_parity();
3460 ALL_JAVA_THREADS(p) {
3461 if (p->claim_oops_do(is_par, cp)) {
3462 tc->do_thread(p);
3463 }
3464 }
3465 VMThread* vmt = VMThread::vm_thread();
3466 if (vmt->claim_oops_do(is_par, cp)) {
3467 tc->do_thread(vmt);
3468 }
3469 }
3470
3471 // The system initialization in the library has three phases.
3472 //
3473 // Phase 1: java.lang.System class initialization
3474 // java.lang.System is a primordial class loaded and initialized
3475 // by the VM early during startup. java.lang.System.<clinit>
3476 // only does registerNatives and keeps the rest of the class
3477 // initialization work later until thread initialization completes.
3478 //
3479 // System.initPhase1 initializes the system properties, the static
3480 // fields in, out, and err. Set up java signal handlers, OS-specific
3481 // system settings, and thread group of the main thread.
3482 static void call_initPhase1(TRAPS) {
3483 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3484 JavaValue result(T_VOID);
3485 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3486 vmSymbols::void_method_signature(), CHECK);
3487 }
3488
3489 // Phase 2. Module system initialization
3490 // This will initialize the module system. Only java.base classes
3491 // can be loaded until phase 2 completes.
3492 //
3493 // Call System.initPhase2 after the compiler initialization and jsr292
3494 // classes get initialized because module initialization runs a lot of java
3495 // code, that for performance reasons, should be compiled. Also, this will
3496 // enable the startup code to use lambda and other language features in this
3497 // phase and onward.
3498 //
3499 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3500 static void call_initPhase2(TRAPS) {
3501 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3502
3503 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3504
3505 JavaValue result(T_INT);
3506 JavaCallArguments args;
3507 args.push_int(DisplayVMOutputToStderr);
3508 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3509 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3510 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3511 if (result.get_jint() != JNI_OK) {
3512 vm_exit_during_initialization(); // no message or exception
3513 }
3514
3515 universe_post_module_init();
3516 }
3517
3518 // Phase 3. final setup - set security manager, system class loader and TCCL
3519 //
3520 // This will instantiate and set the security manager, set the system class
3521 // loader as well as the thread context class loader. The security manager
3522 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3523 // other modules or the application's classpath.
3524 static void call_initPhase3(TRAPS) {
3525 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3526 JavaValue result(T_VOID);
3527 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3528 vmSymbols::void_method_signature(), CHECK);
3529 }
3530
3531 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3532 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3533
3534 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3535 create_vm_init_libraries();
3536 }
3537
3538 initialize_class(vmSymbols::java_lang_String(), CHECK);
3539
3540 // Inject CompactStrings value after the static initializers for String ran.
3541 java_lang_String::set_compact_strings(CompactStrings);
3542
3543 // Initialize java_lang.System (needed before creating the thread)
3544 initialize_class(vmSymbols::java_lang_System(), CHECK);
3545 // The VM creates & returns objects of this class. Make sure it's initialized.
3546 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3547 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3548 Handle thread_group = create_initial_thread_group(CHECK);
3549 Universe::set_main_thread_group(thread_group());
3550 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3551 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3552 main_thread->set_threadObj(thread_object);
3553 // Set thread status to running since main thread has
3554 // been started and running.
3555 java_lang_Thread::set_thread_status(thread_object,
3556 java_lang_Thread::RUNNABLE);
3557
3558 // The VM creates objects of this class.
3559 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3560
3561 // The VM preresolves methods to these classes. Make sure that they get initialized
3562 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3563 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3564
3565 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3566 call_initPhase1(CHECK);
3567
3568 // get the Java runtime name after java.lang.System is initialized
3569 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3570 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3571
3572 // an instance of OutOfMemory exception has been allocated earlier
3573 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3574 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3575 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3576 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3577 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3578 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3579 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3580 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3581 }
3582
3583 void Threads::initialize_jsr292_core_classes(TRAPS) {
3584 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3585
3586 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3587 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3588 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3589 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3590 }
3591
3592 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3593 extern void JDK_Version_init();
3594
3595 // Preinitialize version info.
3596 VM_Version::early_initialize();
3597
3598 // Check version
3599 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3600
3601 // Initialize library-based TLS
3602 ThreadLocalStorage::init();
3603
3604 // Initialize the output stream module
3605 ostream_init();
3606
3607 // Process java launcher properties.
3608 Arguments::process_sun_java_launcher_properties(args);
3609
3610 // Initialize the os module
3611 os::init();
3612
3613 // Record VM creation timing statistics
3614 TraceVmCreationTime create_vm_timer;
3615 create_vm_timer.start();
3616
3617 // Initialize system properties.
3618 Arguments::init_system_properties();
3619
3620 // So that JDK version can be used as a discriminator when parsing arguments
3621 JDK_Version_init();
3622
3623 // Update/Initialize System properties after JDK version number is known
3624 Arguments::init_version_specific_system_properties();
3625
3626 // Make sure to initialize log configuration *before* parsing arguments
3627 LogConfiguration::initialize(create_vm_timer.begin_time());
3628
3629 // Parse arguments
3630 // Note: this internally calls os::init_container_support()
3631 jint parse_result = Arguments::parse(args);
3632 if (parse_result != JNI_OK) return parse_result;
3633
3634 os::init_before_ergo();
3635
3636 jint ergo_result = Arguments::apply_ergo();
3637 if (ergo_result != JNI_OK) return ergo_result;
3638
3639 // Final check of all ranges after ergonomics which may change values.
3640 if (!CommandLineFlagRangeList::check_ranges()) {
3641 return JNI_EINVAL;
3642 }
3643
3644 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3645 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3646 if (!constraint_result) {
3647 return JNI_EINVAL;
3648 }
3649
3650 CommandLineFlagWriteableList::mark_startup();
3651
3652 if (PauseAtStartup) {
3653 os::pause();
3654 }
3655
3656 HOTSPOT_VM_INIT_BEGIN();
3657
3658 // Timing (must come after argument parsing)
3659 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3660
3661 // Initialize the os module after parsing the args
3662 jint os_init_2_result = os::init_2();
3663 if (os_init_2_result != JNI_OK) return os_init_2_result;
3664
3665 SafepointMechanism::initialize();
3666
3667 jint adjust_after_os_result = Arguments::adjust_after_os();
3668 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3669
3670 // Initialize output stream logging
3671 ostream_init_log();
3672
3673 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3674 // Must be before create_vm_init_agents()
3675 if (Arguments::init_libraries_at_startup()) {
3676 convert_vm_init_libraries_to_agents();
3677 }
3678
3679 // Launch -agentlib/-agentpath and converted -Xrun agents
3680 if (Arguments::init_agents_at_startup()) {
3681 create_vm_init_agents();
3682 }
3683
3684 // Initialize Threads state
3685 _thread_list = NULL;
3686 _number_of_threads = 0;
3687 _number_of_non_daemon_threads = 0;
3688
3689 // Initialize global data structures and create system classes in heap
3690 vm_init_globals();
3691
3692 #if INCLUDE_JVMCI
3693 if (JVMCICounterSize > 0) {
3694 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3695 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3696 } else {
3697 JavaThread::_jvmci_old_thread_counters = NULL;
3698 }
3699 #endif // INCLUDE_JVMCI
3700
3701 // Attach the main thread to this os thread
3702 JavaThread* main_thread = new JavaThread();
3703 main_thread->set_thread_state(_thread_in_vm);
3704 main_thread->initialize_thread_current();
3705 // must do this before set_active_handles
3706 main_thread->record_stack_base_and_size();
3707 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3708
3709 if (!main_thread->set_as_starting_thread()) {
3710 vm_shutdown_during_initialization(
3711 "Failed necessary internal allocation. Out of swap space");
3712 main_thread->smr_delete();
3713 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3714 return JNI_ENOMEM;
3715 }
3716
3717 // Enable guard page *after* os::create_main_thread(), otherwise it would
3718 // crash Linux VM, see notes in os_linux.cpp.
3719 main_thread->create_stack_guard_pages();
3720
3721 // Initialize Java-Level synchronization subsystem
3722 ObjectMonitor::Initialize();
3723
3724 // Initialize global modules
3725 jint status = init_globals();
3726 if (status != JNI_OK) {
3727 main_thread->smr_delete();
3728 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3729 return status;
3730 }
3731
3732 if (TRACE_INITIALIZE() != JNI_OK) {
3733 vm_exit_during_initialization("Failed to initialize tracing backend");
3734 }
3735
3736 // Should be done after the heap is fully created
3737 main_thread->cache_global_variables();
3738
3739 HandleMark hm;
3740
3741 { MutexLocker mu(Threads_lock);
3742 Threads::add(main_thread);
3743 }
3744
3745 // Any JVMTI raw monitors entered in onload will transition into
3746 // real raw monitor. VM is setup enough here for raw monitor enter.
3747 JvmtiExport::transition_pending_onload_raw_monitors();
3748
3749 // Create the VMThread
3750 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3751
3752 VMThread::create();
3753 Thread* vmthread = VMThread::vm_thread();
3754
3755 if (!os::create_thread(vmthread, os::vm_thread)) {
3756 vm_exit_during_initialization("Cannot create VM thread. "
3757 "Out of system resources.");
3758 }
3759
3760 // Wait for the VM thread to become ready, and VMThread::run to initialize
3761 // Monitors can have spurious returns, must always check another state flag
3762 {
3763 MutexLocker ml(Notify_lock);
3764 os::start_thread(vmthread);
3765 while (vmthread->active_handles() == NULL) {
3766 Notify_lock->wait();
3767 }
3768 }
3769 }
3770
3771 assert(Universe::is_fully_initialized(), "not initialized");
3772 if (VerifyDuringStartup) {
3773 // Make sure we're starting with a clean slate.
3774 VM_Verify verify_op;
3775 VMThread::execute(&verify_op);
3776 }
3777
3778 Thread* THREAD = Thread::current();
3779
3780 // Always call even when there are not JVMTI environments yet, since environments
3781 // may be attached late and JVMTI must track phases of VM execution
3782 JvmtiExport::enter_early_start_phase();
3783
3784 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3785 JvmtiExport::post_early_vm_start();
3786
3787 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3788
3789 // We need this for ClassDataSharing - the initial vm.info property is set
3790 // with the default value of CDS "sharing" which may be reset through
3791 // command line options.
3792 reset_vm_info_property(CHECK_JNI_ERR);
3793
3794 quicken_jni_functions();
3795
3796 // No more stub generation allowed after that point.
3797 StubCodeDesc::freeze();
3798
3799 // Set flag that basic initialization has completed. Used by exceptions and various
3800 // debug stuff, that does not work until all basic classes have been initialized.
3801 set_init_completed();
3802
3803 LogConfiguration::post_initialize();
3804 Metaspace::post_initialize();
3805
3806 HOTSPOT_VM_INIT_END();
3807
3808 // record VM initialization completion time
3809 #if INCLUDE_MANAGEMENT
3810 Management::record_vm_init_completed();
3811 #endif // INCLUDE_MANAGEMENT
3812
3813 // Signal Dispatcher needs to be started before VMInit event is posted
3814 os::signal_init(CHECK_JNI_ERR);
3815
3816 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3817 if (!DisableAttachMechanism) {
3818 AttachListener::vm_start();
3819 if (StartAttachListener || AttachListener::init_at_startup()) {
3820 AttachListener::init();
3821 }
3822 }
3823
3824 // Launch -Xrun agents
3825 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3826 // back-end can launch with -Xdebug -Xrunjdwp.
3827 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3828 create_vm_init_libraries();
3829 }
3830
3831 if (CleanChunkPoolAsync) {
3832 Chunk::start_chunk_pool_cleaner_task();
3833 }
3834
3835 // initialize compiler(s)
3836 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3837 CompileBroker::compilation_init(CHECK_JNI_ERR);
3838 #endif
3839
3840 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3841 // It is done after compilers are initialized, because otherwise compilations of
3842 // signature polymorphic MH intrinsics can be missed
3843 // (see SystemDictionary::find_method_handle_intrinsic).
3844 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3845
3846 // This will initialize the module system. Only java.base classes can be
3847 // loaded until phase 2 completes
3848 call_initPhase2(CHECK_JNI_ERR);
3849
3850 // Always call even when there are not JVMTI environments yet, since environments
3851 // may be attached late and JVMTI must track phases of VM execution
3852 JvmtiExport::enter_start_phase();
3853
3854 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3855 JvmtiExport::post_vm_start();
3856
3857 // Final system initialization including security manager and system class loader
3858 call_initPhase3(CHECK_JNI_ERR);
3859
3860 // cache the system and platform class loaders
3861 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3862
3863 #if INCLUDE_JVMCI
3864 if (EnableJVMCI) {
3865 // Initialize JVMCI eagerly when it is explicitly requested.
3866 // Or when JVMCIPrintProperties is enabled.
3867 // The JVMCI Java initialization code will read this flag and
3868 // do the printing if it's set.
3869 bool init = EagerJVMCI || JVMCIPrintProperties;
3870
3871 if (!init) {
3872 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3873 // compilations via JVMCI will not actually block until JVMCI is initialized.
3874 init = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3875 }
3876
3877 if (init) {
3878 JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
3879 }
3880 }
3881 #endif
3882
3883 // Always call even when there are not JVMTI environments yet, since environments
3884 // may be attached late and JVMTI must track phases of VM execution
3885 JvmtiExport::enter_live_phase();
3886
3887 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3888 JvmtiExport::post_vm_initialized();
3889
3890 if (TRACE_START() != JNI_OK) {
3891 vm_exit_during_initialization("Failed to start tracing backend.");
3892 }
3893
3894 #if INCLUDE_MANAGEMENT
3895 Management::initialize(THREAD);
3896
3897 if (HAS_PENDING_EXCEPTION) {
3898 // management agent fails to start possibly due to
3899 // configuration problem and is responsible for printing
3900 // stack trace if appropriate. Simply exit VM.
3901 vm_exit(1);
3902 }
3903 #endif // INCLUDE_MANAGEMENT
3904
3905 if (MemProfiling) MemProfiler::engage();
3906 StatSampler::engage();
3907 if (CheckJNICalls) JniPeriodicChecker::engage();
3908
3909 BiasedLocking::init();
3910
3911 #if INCLUDE_RTM_OPT
3912 RTMLockingCounters::init();
3913 #endif
3914
3915 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3916 call_postVMInitHook(THREAD);
3917 // The Java side of PostVMInitHook.run must deal with all
3918 // exceptions and provide means of diagnosis.
3919 if (HAS_PENDING_EXCEPTION) {
3920 CLEAR_PENDING_EXCEPTION;
3921 }
3922 }
3923
3924 {
3925 MutexLocker ml(PeriodicTask_lock);
3926 // Make sure the WatcherThread can be started by WatcherThread::start()
3927 // or by dynamic enrollment.
3928 WatcherThread::make_startable();
3929 // Start up the WatcherThread if there are any periodic tasks
3930 // NOTE: All PeriodicTasks should be registered by now. If they
3931 // aren't, late joiners might appear to start slowly (we might
3932 // take a while to process their first tick).
3933 if (PeriodicTask::num_tasks() > 0) {
3934 WatcherThread::start();
3935 }
3936 }
3937
3938 create_vm_timer.end();
3939 #ifdef ASSERT
3940 _vm_complete = true;
3941 #endif
3942
3943 if (DumpSharedSpaces) {
3944 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3945 ShouldNotReachHere();
3946 }
3947
3948 return JNI_OK;
3949 }
3950
3951 // type for the Agent_OnLoad and JVM_OnLoad entry points
3952 extern "C" {
3953 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3954 }
3955 // Find a command line agent library and return its entry point for
3956 // -agentlib: -agentpath: -Xrun
3957 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3958 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3959 const char *on_load_symbols[],
3960 size_t num_symbol_entries) {
3961 OnLoadEntry_t on_load_entry = NULL;
3962 void *library = NULL;
3963
3964 if (!agent->valid()) {
3965 char buffer[JVM_MAXPATHLEN];
3966 char ebuf[1024] = "";
3967 const char *name = agent->name();
3968 const char *msg = "Could not find agent library ";
3969
3970 // First check to see if agent is statically linked into executable
3971 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3972 library = agent->os_lib();
3973 } else if (agent->is_absolute_path()) {
3974 library = os::dll_load(name, ebuf, sizeof ebuf);
3975 if (library == NULL) {
3976 const char *sub_msg = " in absolute path, with error: ";
3977 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3978 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3979 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3980 // If we can't find the agent, exit.
3981 vm_exit_during_initialization(buf, NULL);
3982 FREE_C_HEAP_ARRAY(char, buf);
3983 }
3984 } else {
3985 // Try to load the agent from the standard dll directory
3986 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3987 name)) {
3988 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3989 }
3990 if (library == NULL) { // Try the library path directory.
3991 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
3992 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3993 }
3994 if (library == NULL) {
3995 const char *sub_msg = " on the library path, with error: ";
3996 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
3997
3998 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
3999 strlen(ebuf) + strlen(sub_msg2) + 1;
4000 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4001 if (!agent->is_instrument_lib()) {
4002 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4003 } else {
4004 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4005 }
4006 // If we can't find the agent, exit.
4007 vm_exit_during_initialization(buf, NULL);
4008 FREE_C_HEAP_ARRAY(char, buf);
4009 }
4010 }
4011 }
4012 agent->set_os_lib(library);
4013 agent->set_valid();
4014 }
4015
4016 // Find the OnLoad function.
4017 on_load_entry =
4018 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4019 false,
4020 on_load_symbols,
4021 num_symbol_entries));
4022 return on_load_entry;
4023 }
4024
4025 // Find the JVM_OnLoad entry point
4026 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4027 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4028 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4029 }
4030
4031 // Find the Agent_OnLoad entry point
4032 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4033 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4034 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4035 }
4036
4037 // For backwards compatibility with -Xrun
4038 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4039 // treated like -agentpath:
4040 // Must be called before agent libraries are created
4041 void Threads::convert_vm_init_libraries_to_agents() {
4042 AgentLibrary* agent;
4043 AgentLibrary* next;
4044
4045 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4046 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4047 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4048
4049 // If there is an JVM_OnLoad function it will get called later,
4050 // otherwise see if there is an Agent_OnLoad
4051 if (on_load_entry == NULL) {
4052 on_load_entry = lookup_agent_on_load(agent);
4053 if (on_load_entry != NULL) {
4054 // switch it to the agent list -- so that Agent_OnLoad will be called,
4055 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4056 Arguments::convert_library_to_agent(agent);
4057 } else {
4058 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4059 }
4060 }
4061 }
4062 }
4063
4064 // Create agents for -agentlib: -agentpath: and converted -Xrun
4065 // Invokes Agent_OnLoad
4066 // Called very early -- before JavaThreads exist
4067 void Threads::create_vm_init_agents() {
4068 extern struct JavaVM_ main_vm;
4069 AgentLibrary* agent;
4070
4071 JvmtiExport::enter_onload_phase();
4072
4073 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4074 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4075
4076 if (on_load_entry != NULL) {
4077 // Invoke the Agent_OnLoad function
4078 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4079 if (err != JNI_OK) {
4080 vm_exit_during_initialization("agent library failed to init", agent->name());
4081 }
4082 } else {
4083 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4084 }
4085 }
4086 JvmtiExport::enter_primordial_phase();
4087 }
4088
4089 extern "C" {
4090 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4091 }
4092
4093 void Threads::shutdown_vm_agents() {
4094 // Send any Agent_OnUnload notifications
4095 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4096 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4097 extern struct JavaVM_ main_vm;
4098 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4099
4100 // Find the Agent_OnUnload function.
4101 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4102 os::find_agent_function(agent,
4103 false,
4104 on_unload_symbols,
4105 num_symbol_entries));
4106
4107 // Invoke the Agent_OnUnload function
4108 if (unload_entry != NULL) {
4109 JavaThread* thread = JavaThread::current();
4110 ThreadToNativeFromVM ttn(thread);
4111 HandleMark hm(thread);
4112 (*unload_entry)(&main_vm);
4113 }
4114 }
4115 }
4116
4117 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4118 // Invokes JVM_OnLoad
4119 void Threads::create_vm_init_libraries() {
4120 extern struct JavaVM_ main_vm;
4121 AgentLibrary* agent;
4122
4123 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4124 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4125
4126 if (on_load_entry != NULL) {
4127 // Invoke the JVM_OnLoad function
4128 JavaThread* thread = JavaThread::current();
4129 ThreadToNativeFromVM ttn(thread);
4130 HandleMark hm(thread);
4131 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4132 if (err != JNI_OK) {
4133 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4134 }
4135 } else {
4136 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4137 }
4138 }
4139 }
4140
4141
4142 // Last thread running calls java.lang.Shutdown.shutdown()
4143 void JavaThread::invoke_shutdown_hooks() {
4144 HandleMark hm(this);
4145
4146 // We could get here with a pending exception, if so clear it now.
4147 if (this->has_pending_exception()) {
4148 this->clear_pending_exception();
4149 }
4150
4151 EXCEPTION_MARK;
4152 Klass* shutdown_klass =
4153 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4154 THREAD);
4155 if (shutdown_klass != NULL) {
4156 // SystemDictionary::resolve_or_null will return null if there was
4157 // an exception. If we cannot load the Shutdown class, just don't
4158 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4159 // won't be run. Note that if a shutdown hook was registered,
4160 // the Shutdown class would have already been loaded
4161 // (Runtime.addShutdownHook will load it).
4162 JavaValue result(T_VOID);
4163 JavaCalls::call_static(&result,
4164 shutdown_klass,
4165 vmSymbols::shutdown_method_name(),
4166 vmSymbols::void_method_signature(),
4167 THREAD);
4168 }
4169 CLEAR_PENDING_EXCEPTION;
4170 }
4171
4172 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4173 // the program falls off the end of main(). Another VM exit path is through
4174 // vm_exit() when the program calls System.exit() to return a value or when
4175 // there is a serious error in VM. The two shutdown paths are not exactly
4176 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4177 // and VM_Exit op at VM level.
4178 //
4179 // Shutdown sequence:
4180 // + Shutdown native memory tracking if it is on
4181 // + Wait until we are the last non-daemon thread to execute
4182 // <-- every thing is still working at this moment -->
4183 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4184 // shutdown hooks
4185 // + Call before_exit(), prepare for VM exit
4186 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4187 // currently the only user of this mechanism is File.deleteOnExit())
4188 // > stop StatSampler, watcher thread, CMS threads,
4189 // post thread end and vm death events to JVMTI,
4190 // stop signal thread
4191 // + Call JavaThread::exit(), it will:
4192 // > release JNI handle blocks, remove stack guard pages
4193 // > remove this thread from Threads list
4194 // <-- no more Java code from this thread after this point -->
4195 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4196 // the compiler threads at safepoint
4197 // <-- do not use anything that could get blocked by Safepoint -->
4198 // + Disable tracing at JNI/JVM barriers
4199 // + Set _vm_exited flag for threads that are still running native code
4200 // + Delete this thread
4201 // + Call exit_globals()
4202 // > deletes tty
4203 // > deletes PerfMemory resources
4204 // + Return to caller
4205
4206 bool Threads::destroy_vm() {
4207 JavaThread* thread = JavaThread::current();
4208
4209 #ifdef ASSERT
4210 _vm_complete = false;
4211 #endif
4212 // Wait until we are the last non-daemon thread to execute
4213 { MutexLocker nu(Threads_lock);
4214 while (Threads::number_of_non_daemon_threads() > 1)
4215 // This wait should make safepoint checks, wait without a timeout,
4216 // and wait as a suspend-equivalent condition.
4217 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4218 Mutex::_as_suspend_equivalent_flag);
4219 }
4220
4221 EventShutdown e;
4222 if (e.should_commit()) {
4223 e.set_reason("No remaining non-daemon Java threads");
4224 e.commit();
4225 }
4226
4227 // Hang forever on exit if we are reporting an error.
4228 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4229 os::infinite_sleep();
4230 }
4231 os::wait_for_keypress_at_exit();
4232
4233 // run Java level shutdown hooks
4234 thread->invoke_shutdown_hooks();
4235
4236 before_exit(thread);
4237
4238 thread->exit(true);
4239
4240 // Stop VM thread.
4241 {
4242 // 4945125 The vm thread comes to a safepoint during exit.
4243 // GC vm_operations can get caught at the safepoint, and the
4244 // heap is unparseable if they are caught. Grab the Heap_lock
4245 // to prevent this. The GC vm_operations will not be able to
4246 // queue until after the vm thread is dead. After this point,
4247 // we'll never emerge out of the safepoint before the VM exits.
4248
4249 MutexLocker ml(Heap_lock);
4250
4251 VMThread::wait_for_vm_thread_exit();
4252 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4253 VMThread::destroy();
4254 }
4255
4256 // clean up ideal graph printers
4257 #if defined(COMPILER2) && !defined(PRODUCT)
4258 IdealGraphPrinter::clean_up();
4259 #endif
4260
4261 // Now, all Java threads are gone except daemon threads. Daemon threads
4262 // running Java code or in VM are stopped by the Safepoint. However,
4263 // daemon threads executing native code are still running. But they
4264 // will be stopped at native=>Java/VM barriers. Note that we can't
4265 // simply kill or suspend them, as it is inherently deadlock-prone.
4266
4267 VM_Exit::set_vm_exited();
4268
4269 notify_vm_shutdown();
4270
4271 // We are after VM_Exit::set_vm_exited() so we can't call
4272 // thread->smr_delete() or we will block on the Threads_lock.
4273 // Deleting the shutdown thread here is safe because another
4274 // JavaThread cannot have an active ThreadsListHandle for
4275 // this JavaThread.
4276 delete thread;
4277
4278 #if INCLUDE_JVMCI
4279 if (JVMCICounterSize > 0) {
4280 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4281 }
4282 #endif
4283
4284 // exit_globals() will delete tty
4285 exit_globals();
4286
4287 LogConfiguration::finalize();
4288
4289 return true;
4290 }
4291
4292
4293 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4294 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4295 return is_supported_jni_version(version);
4296 }
4297
4298
4299 jboolean Threads::is_supported_jni_version(jint version) {
4300 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4301 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4302 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4303 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4304 if (version == JNI_VERSION_9) return JNI_TRUE;
4305 if (version == JNI_VERSION_10) return JNI_TRUE;
4306 return JNI_FALSE;
4307 }
4308
4309
4310 void Threads::add(JavaThread* p, bool force_daemon) {
4311 // The threads lock must be owned at this point
4312 assert_locked_or_safepoint(Threads_lock);
4313
4314 BarrierSet::barrier_set()->on_thread_attach(p);
4315
4316 p->set_next(_thread_list);
4317 _thread_list = p;
4318
4319 // Once a JavaThread is added to the Threads list, smr_delete() has
4320 // to be used to delete it. Otherwise we can just delete it directly.
4321 p->set_on_thread_list();
4322
4323 _number_of_threads++;
4324 oop threadObj = p->threadObj();
4325 bool daemon = true;
4326 // Bootstrapping problem: threadObj can be null for initial
4327 // JavaThread (or for threads attached via JNI)
4328 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4329 _number_of_non_daemon_threads++;
4330 daemon = false;
4331 }
4332
4333 ThreadService::add_thread(p, daemon);
4334
4335 // Maintain fast thread list
4336 ThreadsSMRSupport::add_thread(p);
4337
4338 // Possible GC point.
4339 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4340 }
4341
4342 void Threads::remove(JavaThread* p) {
4343
4344 // Reclaim the objectmonitors from the omInUseList and omFreeList of the moribund thread.
4345 ObjectSynchronizer::omFlush(p);
4346
4347 // Extra scope needed for Thread_lock, so we can check
4348 // that we do not remove thread without safepoint code notice
4349 { MutexLocker ml(Threads_lock);
4350
4351 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4352
4353 // Maintain fast thread list
4354 ThreadsSMRSupport::remove_thread(p);
4355
4356 JavaThread* current = _thread_list;
4357 JavaThread* prev = NULL;
4358
4359 while (current != p) {
4360 prev = current;
4361 current = current->next();
4362 }
4363
4364 if (prev) {
4365 prev->set_next(current->next());
4366 } else {
4367 _thread_list = p->next();
4368 }
4369
4370 _number_of_threads--;
4371 oop threadObj = p->threadObj();
4372 bool daemon = true;
4373 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4374 _number_of_non_daemon_threads--;
4375 daemon = false;
4376
4377 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4378 // on destroy_vm will wake up.
4379 if (number_of_non_daemon_threads() == 1) {
4380 Threads_lock->notify_all();
4381 }
4382 }
4383 ThreadService::remove_thread(p, daemon);
4384
4385 // Make sure that safepoint code disregard this thread. This is needed since
4386 // the thread might mess around with locks after this point. This can cause it
4387 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4388 // of this thread since it is removed from the queue.
4389 p->set_terminated_value();
4390 } // unlock Threads_lock
4391
4392 // Since Events::log uses a lock, we grab it outside the Threads_lock
4393 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4394 }
4395
4396 // Operations on the Threads list for GC. These are not explicitly locked,
4397 // but the garbage collector must provide a safe context for them to run.
4398 // In particular, these things should never be called when the Threads_lock
4399 // is held by some other thread. (Note: the Safepoint abstraction also
4400 // uses the Threads_lock to guarantee this property. It also makes sure that
4401 // all threads gets blocked when exiting or starting).
4402
4403 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4404 ALL_JAVA_THREADS(p) {
4405 p->oops_do(f, cf);
4406 }
4407 VMThread::vm_thread()->oops_do(f, cf);
4408 }
4409
4410 void Threads::change_thread_claim_parity() {
4411 // Set the new claim parity.
4412 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4413 "Not in range.");
4414 _thread_claim_parity++;
4415 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4416 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4417 "Not in range.");
4418 }
4419
4420 #ifdef ASSERT
4421 void Threads::assert_all_threads_claimed() {
4422 ALL_JAVA_THREADS(p) {
4423 const int thread_parity = p->oops_do_parity();
4424 assert((thread_parity == _thread_claim_parity),
4425 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4426 }
4427 VMThread* vmt = VMThread::vm_thread();
4428 const int thread_parity = vmt->oops_do_parity();
4429 assert((thread_parity == _thread_claim_parity),
4430 "VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
4431 }
4432 #endif // ASSERT
4433
4434 class ParallelOopsDoThreadClosure : public ThreadClosure {
4435 private:
4436 OopClosure* _f;
4437 CodeBlobClosure* _cf;
4438 public:
4439 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4440 void do_thread(Thread* t) {
4441 t->oops_do(_f, _cf);
4442 }
4443 };
4444
4445 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4446 ParallelOopsDoThreadClosure tc(f, cf);
4447 possibly_parallel_threads_do(is_par, &tc);
4448 }
4449
4450 #if INCLUDE_ALL_GCS
4451 // Used by ParallelScavenge
4452 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4453 ALL_JAVA_THREADS(p) {
4454 q->enqueue(new ThreadRootsTask(p));
4455 }
4456 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4457 }
4458
4459 // Used by Parallel Old
4460 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4461 ALL_JAVA_THREADS(p) {
4462 q->enqueue(new ThreadRootsMarkingTask(p));
4463 }
4464 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4465 }
4466 #endif // INCLUDE_ALL_GCS
4467
4468 void Threads::nmethods_do(CodeBlobClosure* cf) {
4469 ALL_JAVA_THREADS(p) {
4470 // This is used by the code cache sweeper to mark nmethods that are active
4471 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4472 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4473 if(!p->is_Code_cache_sweeper_thread()) {
4474 p->nmethods_do(cf);
4475 }
4476 }
4477 }
4478
4479 void Threads::metadata_do(void f(Metadata*)) {
4480 ALL_JAVA_THREADS(p) {
4481 p->metadata_do(f);
4482 }
4483 }
4484
4485 class ThreadHandlesClosure : public ThreadClosure {
4486 void (*_f)(Metadata*);
4487 public:
4488 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4489 virtual void do_thread(Thread* thread) {
4490 thread->metadata_handles_do(_f);
4491 }
4492 };
4493
4494 void Threads::metadata_handles_do(void f(Metadata*)) {
4495 // Only walk the Handles in Thread.
4496 ThreadHandlesClosure handles_closure(f);
4497 threads_do(&handles_closure);
4498 }
4499
4500 void Threads::deoptimized_wrt_marked_nmethods() {
4501 ALL_JAVA_THREADS(p) {
4502 p->deoptimized_wrt_marked_nmethods();
4503 }
4504 }
4505
4506
4507 // Get count Java threads that are waiting to enter the specified monitor.
4508 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4509 int count,
4510 address monitor) {
4511 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4512
4513 int i = 0;
4514 DO_JAVA_THREADS(t_list, p) {
4515 if (!p->can_call_java()) continue;
4516
4517 address pending = (address)p->current_pending_monitor();
4518 if (pending == monitor) { // found a match
4519 if (i < count) result->append(p); // save the first count matches
4520 i++;
4521 }
4522 }
4523
4524 return result;
4525 }
4526
4527
4528 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4529 address owner) {
4530 // NULL owner means not locked so we can skip the search
4531 if (owner == NULL) return NULL;
4532
4533 DO_JAVA_THREADS(t_list, p) {
4534 // first, see if owner is the address of a Java thread
4535 if (owner == (address)p) return p;
4536 }
4537
4538 // Cannot assert on lack of success here since this function may be
4539 // used by code that is trying to report useful problem information
4540 // like deadlock detection.
4541 if (UseHeavyMonitors) return NULL;
4542
4543 // If we didn't find a matching Java thread and we didn't force use of
4544 // heavyweight monitors, then the owner is the stack address of the
4545 // Lock Word in the owning Java thread's stack.
4546 //
4547 JavaThread* the_owner = NULL;
4548 DO_JAVA_THREADS(t_list, q) {
4549 if (q->is_lock_owned(owner)) {
4550 the_owner = q;
4551 break;
4552 }
4553 }
4554
4555 // cannot assert on lack of success here; see above comment
4556 return the_owner;
4557 }
4558
4559 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4560 void Threads::print_on(outputStream* st, bool print_stacks,
4561 bool internal_format, bool print_concurrent_locks) {
4562 char buf[32];
4563 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4564
4565 st->print_cr("Full thread dump %s (%s %s):",
4566 Abstract_VM_Version::vm_name(),
4567 Abstract_VM_Version::vm_release(),
4568 Abstract_VM_Version::vm_info_string());
4569 st->cr();
4570
4571 #if INCLUDE_SERVICES
4572 // Dump concurrent locks
4573 ConcurrentLocksDump concurrent_locks;
4574 if (print_concurrent_locks) {
4575 concurrent_locks.dump_at_safepoint();
4576 }
4577 #endif // INCLUDE_SERVICES
4578
4579 ThreadsSMRSupport::print_info_on(st);
4580 st->cr();
4581
4582 ALL_JAVA_THREADS(p) {
4583 ResourceMark rm;
4584 p->print_on(st);
4585 if (print_stacks) {
4586 if (internal_format) {
4587 p->trace_stack();
4588 } else {
4589 p->print_stack_on(st);
4590 }
4591 }
4592 st->cr();
4593 #if INCLUDE_SERVICES
4594 if (print_concurrent_locks) {
4595 concurrent_locks.print_locks_on(p, st);
4596 }
4597 #endif // INCLUDE_SERVICES
4598 }
4599
4600 VMThread::vm_thread()->print_on(st);
4601 st->cr();
4602 Universe::heap()->print_gc_threads_on(st);
4603 WatcherThread* wt = WatcherThread::watcher_thread();
4604 if (wt != NULL) {
4605 wt->print_on(st);
4606 st->cr();
4607 }
4608
4609 st->flush();
4610 }
4611
4612 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4613 int buflen, bool* found_current) {
4614 if (this_thread != NULL) {
4615 bool is_current = (current == this_thread);
4616 *found_current = *found_current || is_current;
4617 st->print("%s", is_current ? "=>" : " ");
4618
4619 st->print(PTR_FORMAT, p2i(this_thread));
4620 st->print(" ");
4621 this_thread->print_on_error(st, buf, buflen);
4622 st->cr();
4623 }
4624 }
4625
4626 class PrintOnErrorClosure : public ThreadClosure {
4627 outputStream* _st;
4628 Thread* _current;
4629 char* _buf;
4630 int _buflen;
4631 bool* _found_current;
4632 public:
4633 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4634 int buflen, bool* found_current) :
4635 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4636
4637 virtual void do_thread(Thread* thread) {
4638 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4639 }
4640 };
4641
4642 // Threads::print_on_error() is called by fatal error handler. It's possible
4643 // that VM is not at safepoint and/or current thread is inside signal handler.
4644 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4645 // memory (even in resource area), it might deadlock the error handler.
4646 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4647 int buflen) {
4648 ThreadsSMRSupport::print_info_on(st);
4649 st->cr();
4650
4651 bool found_current = false;
4652 st->print_cr("Java Threads: ( => current thread )");
4653 ALL_JAVA_THREADS(thread) {
4654 print_on_error(thread, st, current, buf, buflen, &found_current);
4655 }
4656 st->cr();
4657
4658 st->print_cr("Other Threads:");
4659 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4660 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4661
4662 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4663 Universe::heap()->gc_threads_do(&print_closure);
4664
4665 if (!found_current) {
4666 st->cr();
4667 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4668 current->print_on_error(st, buf, buflen);
4669 st->cr();
4670 }
4671 st->cr();
4672
4673 st->print_cr("Threads with active compile tasks:");
4674 print_threads_compiling(st, buf, buflen);
4675 }
4676
4677 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) {
4678 ALL_JAVA_THREADS(thread) {
4679 if (thread->is_Compiler_thread()) {
4680 CompilerThread* ct = (CompilerThread*) thread;
4681
4682 // Keep task in local variable for NULL check.
4683 // ct->_task might be set to NULL by concurring compiler thread
4684 // because it completed the compilation. The task is never freed,
4685 // though, just returned to a free list.
4686 CompileTask* task = ct->task();
4687 if (task != NULL) {
4688 thread->print_name_on_error(st, buf, buflen);
4689 task->print(st, NULL, true, true);
4690 }
4691 }
4692 }
4693 }
4694
4695
4696 // Internal SpinLock and Mutex
4697 // Based on ParkEvent
4698
4699 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4700 //
4701 // We employ SpinLocks _only for low-contention, fixed-length
4702 // short-duration critical sections where we're concerned
4703 // about native mutex_t or HotSpot Mutex:: latency.
4704 // The mux construct provides a spin-then-block mutual exclusion
4705 // mechanism.
4706 //
4707 // Testing has shown that contention on the ListLock guarding gFreeList
4708 // is common. If we implement ListLock as a simple SpinLock it's common
4709 // for the JVM to devolve to yielding with little progress. This is true
4710 // despite the fact that the critical sections protected by ListLock are
4711 // extremely short.
4712 //
4713 // TODO-FIXME: ListLock should be of type SpinLock.
4714 // We should make this a 1st-class type, integrated into the lock
4715 // hierarchy as leaf-locks. Critically, the SpinLock structure
4716 // should have sufficient padding to avoid false-sharing and excessive
4717 // cache-coherency traffic.
4718
4719
4720 typedef volatile int SpinLockT;
4721
4722 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4723 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4724 return; // normal fast-path return
4725 }
4726
4727 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4728 TEVENT(SpinAcquire - ctx);
4729 int ctr = 0;
4730 int Yields = 0;
4731 for (;;) {
4732 while (*adr != 0) {
4733 ++ctr;
4734 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4735 if (Yields > 5) {
4736 os::naked_short_sleep(1);
4737 } else {
4738 os::naked_yield();
4739 ++Yields;
4740 }
4741 } else {
4742 SpinPause();
4743 }
4744 }
4745 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4746 }
4747 }
4748
4749 void Thread::SpinRelease(volatile int * adr) {
4750 assert(*adr != 0, "invariant");
4751 OrderAccess::fence(); // guarantee at least release consistency.
4752 // Roach-motel semantics.
4753 // It's safe if subsequent LDs and STs float "up" into the critical section,
4754 // but prior LDs and STs within the critical section can't be allowed
4755 // to reorder or float past the ST that releases the lock.
4756 // Loads and stores in the critical section - which appear in program
4757 // order before the store that releases the lock - must also appear
4758 // before the store that releases the lock in memory visibility order.
4759 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4760 // the ST of 0 into the lock-word which releases the lock, so fence
4761 // more than covers this on all platforms.
4762 *adr = 0;
4763 }
4764
4765 // muxAcquire and muxRelease:
4766 //
4767 // * muxAcquire and muxRelease support a single-word lock-word construct.
4768 // The LSB of the word is set IFF the lock is held.
4769 // The remainder of the word points to the head of a singly-linked list
4770 // of threads blocked on the lock.
4771 //
4772 // * The current implementation of muxAcquire-muxRelease uses its own
4773 // dedicated Thread._MuxEvent instance. If we're interested in
4774 // minimizing the peak number of extant ParkEvent instances then
4775 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4776 // as certain invariants were satisfied. Specifically, care would need
4777 // to be taken with regards to consuming unpark() "permits".
4778 // A safe rule of thumb is that a thread would never call muxAcquire()
4779 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4780 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4781 // consume an unpark() permit intended for monitorenter, for instance.
4782 // One way around this would be to widen the restricted-range semaphore
4783 // implemented in park(). Another alternative would be to provide
4784 // multiple instances of the PlatformEvent() for each thread. One
4785 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4786 //
4787 // * Usage:
4788 // -- Only as leaf locks
4789 // -- for short-term locking only as muxAcquire does not perform
4790 // thread state transitions.
4791 //
4792 // Alternatives:
4793 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4794 // but with parking or spin-then-park instead of pure spinning.
4795 // * Use Taura-Oyama-Yonenzawa locks.
4796 // * It's possible to construct a 1-0 lock if we encode the lockword as
4797 // (List,LockByte). Acquire will CAS the full lockword while Release
4798 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4799 // acquiring threads use timers (ParkTimed) to detect and recover from
4800 // the stranding window. Thread/Node structures must be aligned on 256-byte
4801 // boundaries by using placement-new.
4802 // * Augment MCS with advisory back-link fields maintained with CAS().
4803 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4804 // The validity of the backlinks must be ratified before we trust the value.
4805 // If the backlinks are invalid the exiting thread must back-track through the
4806 // the forward links, which are always trustworthy.
4807 // * Add a successor indication. The LockWord is currently encoded as
4808 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4809 // to provide the usual futile-wakeup optimization.
4810 // See RTStt for details.
4811 // * Consider schedctl.sc_nopreempt to cover the critical section.
4812 //
4813
4814
4815 const intptr_t LOCKBIT = 1;
4816
4817 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4818 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4819 if (w == 0) return;
4820 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4821 return;
4822 }
4823
4824 TEVENT(muxAcquire - Contention);
4825 ParkEvent * const Self = Thread::current()->_MuxEvent;
4826 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4827 for (;;) {
4828 int its = (os::is_MP() ? 100 : 0) + 1;
4829
4830 // Optional spin phase: spin-then-park strategy
4831 while (--its >= 0) {
4832 w = *Lock;
4833 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4834 return;
4835 }
4836 }
4837
4838 Self->reset();
4839 Self->OnList = intptr_t(Lock);
4840 // The following fence() isn't _strictly necessary as the subsequent
4841 // CAS() both serializes execution and ratifies the fetched *Lock value.
4842 OrderAccess::fence();
4843 for (;;) {
4844 w = *Lock;
4845 if ((w & LOCKBIT) == 0) {
4846 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4847 Self->OnList = 0; // hygiene - allows stronger asserts
4848 return;
4849 }
4850 continue; // Interference -- *Lock changed -- Just retry
4851 }
4852 assert(w & LOCKBIT, "invariant");
4853 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4854 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4855 }
4856
4857 while (Self->OnList != 0) {
4858 Self->park();
4859 }
4860 }
4861 }
4862
4863 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4864 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4865 if (w == 0) return;
4866 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4867 return;
4868 }
4869
4870 TEVENT(muxAcquire - Contention);
4871 ParkEvent * ReleaseAfter = NULL;
4872 if (ev == NULL) {
4873 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4874 }
4875 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4876 for (;;) {
4877 guarantee(ev->OnList == 0, "invariant");
4878 int its = (os::is_MP() ? 100 : 0) + 1;
4879
4880 // Optional spin phase: spin-then-park strategy
4881 while (--its >= 0) {
4882 w = *Lock;
4883 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4884 if (ReleaseAfter != NULL) {
4885 ParkEvent::Release(ReleaseAfter);
4886 }
4887 return;
4888 }
4889 }
4890
4891 ev->reset();
4892 ev->OnList = intptr_t(Lock);
4893 // The following fence() isn't _strictly necessary as the subsequent
4894 // CAS() both serializes execution and ratifies the fetched *Lock value.
4895 OrderAccess::fence();
4896 for (;;) {
4897 w = *Lock;
4898 if ((w & LOCKBIT) == 0) {
4899 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4900 ev->OnList = 0;
4901 // We call ::Release while holding the outer lock, thus
4902 // artificially lengthening the critical section.
4903 // Consider deferring the ::Release() until the subsequent unlock(),
4904 // after we've dropped the outer lock.
4905 if (ReleaseAfter != NULL) {
4906 ParkEvent::Release(ReleaseAfter);
4907 }
4908 return;
4909 }
4910 continue; // Interference -- *Lock changed -- Just retry
4911 }
4912 assert(w & LOCKBIT, "invariant");
4913 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4914 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4915 }
4916
4917 while (ev->OnList != 0) {
4918 ev->park();
4919 }
4920 }
4921 }
4922
4923 // Release() must extract a successor from the list and then wake that thread.
4924 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4925 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4926 // Release() would :
4927 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4928 // (B) Extract a successor from the private list "in-hand"
4929 // (C) attempt to CAS() the residual back into *Lock over null.
4930 // If there were any newly arrived threads and the CAS() would fail.
4931 // In that case Release() would detach the RATs, re-merge the list in-hand
4932 // with the RATs and repeat as needed. Alternately, Release() might
4933 // detach and extract a successor, but then pass the residual list to the wakee.
4934 // The wakee would be responsible for reattaching and remerging before it
4935 // competed for the lock.
4936 //
4937 // Both "pop" and DMR are immune from ABA corruption -- there can be
4938 // multiple concurrent pushers, but only one popper or detacher.
4939 // This implementation pops from the head of the list. This is unfair,
4940 // but tends to provide excellent throughput as hot threads remain hot.
4941 // (We wake recently run threads first).
4942 //
4943 // All paths through muxRelease() will execute a CAS.
4944 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4945 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4946 // executed within the critical section are complete and globally visible before the
4947 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4948 void Thread::muxRelease(volatile intptr_t * Lock) {
4949 for (;;) {
4950 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
4951 assert(w & LOCKBIT, "invariant");
4952 if (w == LOCKBIT) return;
4953 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4954 assert(List != NULL, "invariant");
4955 assert(List->OnList == intptr_t(Lock), "invariant");
4956 ParkEvent * const nxt = List->ListNext;
4957 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4958
4959 // The following CAS() releases the lock and pops the head element.
4960 // The CAS() also ratifies the previously fetched lock-word value.
4961 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
4962 continue;
4963 }
4964 List->OnList = 0;
4965 OrderAccess::fence();
4966 List->unpark();
4967 return;
4968 }
4969 }
4970
4971
4972 void Threads::verify() {
4973 ALL_JAVA_THREADS(p) {
4974 p->verify();
4975 }
4976 VMThread* thread = VMThread::vm_thread();
4977 if (thread != NULL) thread->verify();
4978 }