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/barrierSet.hpp"
37 #include "gc/shared/gcId.hpp"
38 #include "gc/shared/gcLocker.inline.hpp"
39 #include "gc/shared/workgroup.hpp"
40 #include "interpreter/interpreter.hpp"
41 #include "interpreter/linkResolver.hpp"
42 #include "interpreter/oopMapCache.hpp"
43 #include "jfr/jfrEvents.hpp"
44 #include "jfr/support/jfrThreadId.hpp"
45 #include "jvmtifiles/jvmtiEnv.hpp"
46 #include "logging/log.hpp"
47 #include "logging/logConfiguration.hpp"
48 #include "logging/logStream.hpp"
49 #include "memory/allocation.inline.hpp"
50 #include "memory/metaspaceShared.hpp"
51 #include "memory/oopFactory.hpp"
52 #include "memory/resourceArea.hpp"
53 #include "memory/universe.hpp"
54 #include "oops/access.inline.hpp"
55 #include "oops/instanceKlass.hpp"
56 #include "oops/objArrayOop.hpp"
57 #include "oops/oop.inline.hpp"
58 #include "oops/symbol.hpp"
59 #include "oops/typeArrayOop.inline.hpp"
60 #include "oops/verifyOopClosure.hpp"
61 #include "prims/jvm_misc.hpp"
62 #include "prims/jvmtiExport.hpp"
63 #include "prims/jvmtiThreadState.hpp"
64 #include "prims/privilegedStack.hpp"
65 #include "runtime/arguments.hpp"
66 #include "runtime/atomic.hpp"
67 #include "runtime/biasedLocking.hpp"
68 #include "runtime/flags/jvmFlagConstraintList.hpp"
69 #include "runtime/flags/jvmFlagRangeList.hpp"
70 #include "runtime/flags/jvmFlagWriteableList.hpp"
71 #include "runtime/deoptimization.hpp"
72 #include "runtime/frame.inline.hpp"
73 #include "runtime/handshake.hpp"
74 #include "runtime/init.hpp"
75 #include "runtime/interfaceSupport.inline.hpp"
76 #include "runtime/java.hpp"
77 #include "runtime/javaCalls.hpp"
78 #include "runtime/jniHandles.inline.hpp"
79 #include "runtime/jniPeriodicChecker.hpp"
80 #include "runtime/memprofiler.hpp"
81 #include "runtime/mutexLocker.hpp"
82 #include "runtime/objectMonitor.hpp"
83 #include "runtime/orderAccess.hpp"
84 #include "runtime/osThread.hpp"
85 #include "runtime/prefetch.inline.hpp"
86 #include "runtime/safepoint.hpp"
87 #include "runtime/safepointMechanism.inline.hpp"
88 #include "runtime/sharedRuntime.hpp"
89 #include "runtime/statSampler.hpp"
90 #include "runtime/stubRoutines.hpp"
91 #include "runtime/sweeper.hpp"
92 #include "runtime/task.hpp"
93 #include "runtime/thread.inline.hpp"
94 #include "runtime/threadCritical.hpp"
95 #include "runtime/threadSMR.inline.hpp"
96 #include "runtime/timer.hpp"
97 #include "runtime/timerTrace.hpp"
98 #include "runtime/vframe.inline.hpp"
99 #include "runtime/vframeArray.hpp"
100 #include "runtime/vframe_hp.hpp"
101 #include "runtime/vmThread.hpp"
102 #include "runtime/vm_operations.hpp"
103 #include "runtime/vm_version.hpp"
104 #include "services/attachListener.hpp"
105 #include "services/management.hpp"
106 #include "services/memTracker.hpp"
107 #include "services/threadService.hpp"
108 #include "utilities/align.hpp"
109 #include "utilities/copy.hpp"
110 #include "utilities/defaultStream.hpp"
111 #include "utilities/dtrace.hpp"
112 #include "utilities/events.hpp"
113 #include "utilities/macros.hpp"
114 #include "utilities/preserveException.hpp"
115 #include "utilities/vmError.hpp"
116 #if INCLUDE_JVMCI
117 #include "jvmci/jvmciCompiler.hpp"
118 #include "jvmci/jvmciRuntime.hpp"
119 #include "logging/logHandle.hpp"
120 #endif
121 #ifdef COMPILER1
122 #include "c1/c1_Compiler.hpp"
123 #endif
124 #ifdef COMPILER2
125 #include "opto/c2compiler.hpp"
126 #include "opto/idealGraphPrinter.hpp"
127 #endif
128 #if INCLUDE_RTM_OPT
129 #include "runtime/rtmLocking.hpp"
130 #endif
131 #if INCLUDE_JFR
132 #include "jfr/jfr.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 _threads_list_ptr = NULL;
244 _nested_threads_hazard_ptr_cnt = 0;
245 _rcu_counter = 0;
246
247 // the handle mark links itself to last_handle_mark
248 new HandleMark(this);
249
250 // plain initialization
251 debug_only(_owned_locks = NULL;)
252 debug_only(_allow_allocation_count = 0;)
253 NOT_PRODUCT(_allow_safepoint_count = 0;)
254 NOT_PRODUCT(_skip_gcalot = false;)
255 _jvmti_env_iteration_count = 0;
256 set_allocated_bytes(0);
257 _vm_operation_started_count = 0;
258 _vm_operation_completed_count = 0;
259 _current_pending_monitor = NULL;
260 _current_pending_monitor_is_from_java = true;
261 _current_waiting_monitor = NULL;
262 _num_nested_signal = 0;
263 omFreeList = NULL;
264 omFreeCount = 0;
265 omFreeProvision = 32;
266 omInUseList = NULL;
267 omInUseCount = 0;
268
269 #ifdef ASSERT
270 _visited_for_critical_count = false;
271 #endif
272
273 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
274 Monitor::_safepoint_check_sometimes);
275 _suspend_flags = 0;
276
277 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
278 _hashStateX = os::random();
279 _hashStateY = 842502087;
280 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
281 _hashStateW = 273326509;
282
283 _OnTrap = 0;
284 _schedctl = NULL;
285 _Stalled = 0;
286 _TypeTag = 0x2BAD;
287
288 // Many of the following fields are effectively final - immutable
289 // Note that nascent threads can't use the Native Monitor-Mutex
290 // construct until the _MutexEvent is initialized ...
291 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
292 // we might instead use a stack of ParkEvents that we could provision on-demand.
293 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
294 // and ::Release()
295 _ParkEvent = ParkEvent::Allocate(this);
296 _SleepEvent = ParkEvent::Allocate(this);
297 _MutexEvent = ParkEvent::Allocate(this);
298 _MuxEvent = ParkEvent::Allocate(this);
299
300 #ifdef CHECK_UNHANDLED_OOPS
301 if (CheckUnhandledOops) {
302 _unhandled_oops = new UnhandledOops(this);
303 }
304 #endif // CHECK_UNHANDLED_OOPS
305 #ifdef ASSERT
306 if (UseBiasedLocking) {
307 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
308 assert(this == _real_malloc_address ||
309 this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
310 "bug in forced alignment of thread objects");
311 }
312 #endif // ASSERT
313
314 // Notify the barrier set that a thread is being created. Note that the
315 // main thread is created before a barrier set is available. The call to
316 // BarrierSet::on_thread_create() for the main thread is therefore deferred
317 // until it calls BarrierSet::set_barrier_set().
318 BarrierSet* const barrier_set = BarrierSet::barrier_set();
319 if (barrier_set != NULL) {
320 barrier_set->on_thread_create(this);
321 }
322 }
323
324 void Thread::initialize_thread_current() {
325 #ifndef USE_LIBRARY_BASED_TLS_ONLY
326 assert(_thr_current == NULL, "Thread::current already initialized");
327 _thr_current = this;
328 #endif
329 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
330 ThreadLocalStorage::set_thread(this);
331 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
332 }
333
334 void Thread::clear_thread_current() {
335 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
336 #ifndef USE_LIBRARY_BASED_TLS_ONLY
337 _thr_current = NULL;
338 #endif
339 ThreadLocalStorage::set_thread(NULL);
340 }
341
342 void Thread::record_stack_base_and_size() {
343 set_stack_base(os::current_stack_base());
344 set_stack_size(os::current_stack_size());
345 // CR 7190089: on Solaris, primordial thread's stack is adjusted
346 // in initialize_thread(). Without the adjustment, stack size is
347 // incorrect if stack is set to unlimited (ulimit -s unlimited).
348 // So far, only Solaris has real implementation of initialize_thread().
349 //
350 // set up any platform-specific state.
351 os::initialize_thread(this);
352
353 // Set stack limits after thread is initialized.
354 if (is_Java_thread()) {
355 ((JavaThread*) this)->set_stack_overflow_limit();
356 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
357 }
358 #if INCLUDE_NMT
359 // record thread's native stack, stack grows downward
360 MemTracker::record_thread_stack(stack_end(), stack_size());
361 #endif // INCLUDE_NMT
362 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
363 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
364 os::current_thread_id(), p2i(stack_base() - stack_size()),
365 p2i(stack_base()), stack_size()/1024);
366 }
367
368
369 Thread::~Thread() {
370 JFR_ONLY(Jfr::on_thread_destruct(this);)
371
372 // Notify the barrier set that a thread is being destroyed. Note that a barrier
373 // set might not be available if we encountered errors during bootstrapping.
374 BarrierSet* const barrier_set = BarrierSet::barrier_set();
375 if (barrier_set != NULL) {
376 barrier_set->on_thread_destroy(this);
377 }
378
379
380 // stack_base can be NULL if the thread is never started or exited before
381 // record_stack_base_and_size called. Although, we would like to ensure
382 // that all started threads do call record_stack_base_and_size(), there is
383 // not proper way to enforce that.
384 #if INCLUDE_NMT
385 if (_stack_base != NULL) {
386 MemTracker::release_thread_stack(stack_end(), stack_size());
387 #ifdef ASSERT
388 set_stack_base(NULL);
389 #endif
390 }
391 #endif // INCLUDE_NMT
392
393 // deallocate data structures
394 delete resource_area();
395 // since the handle marks are using the handle area, we have to deallocated the root
396 // handle mark before deallocating the thread's handle area,
397 assert(last_handle_mark() != NULL, "check we have an element");
398 delete last_handle_mark();
399 assert(last_handle_mark() == NULL, "check we have reached the end");
400
401 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
402 // We NULL out the fields for good hygiene.
403 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
404 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
405 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
406 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
407
408 delete handle_area();
409 delete metadata_handles();
410
411 // SR_handler uses this as a termination indicator -
412 // needs to happen before os::free_thread()
413 delete _SR_lock;
414 _SR_lock = NULL;
415
416 // osthread() can be NULL, if creation of thread failed.
417 if (osthread() != NULL) os::free_thread(osthread());
418
419 // clear Thread::current if thread is deleting itself.
420 // Needed to ensure JNI correctly detects non-attached threads.
421 if (this == Thread::current()) {
422 clear_thread_current();
423 }
424
425 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
426 }
427
428 // NOTE: dummy function for assertion purpose.
429 void Thread::run() {
430 ShouldNotReachHere();
431 }
432
433 #ifdef ASSERT
434 // A JavaThread is considered "dangling" if it is not the current
435 // thread, has been added the Threads list, the system is not at a
436 // safepoint and the Thread is not "protected".
437 //
438 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
439 assert(!thread->is_Java_thread() || Thread::current() == thread ||
440 !((JavaThread *) thread)->on_thread_list() ||
441 SafepointSynchronize::is_at_safepoint() ||
442 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
443 "possibility of dangling Thread pointer");
444 }
445 #endif
446
447 ThreadPriority Thread::get_priority(const Thread* const thread) {
448 ThreadPriority priority;
449 // Can return an error!
450 (void)os::get_priority(thread, priority);
451 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
452 return priority;
453 }
454
455 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
456 debug_only(check_for_dangling_thread_pointer(thread);)
457 // Can return an error!
458 (void)os::set_priority(thread, priority);
459 }
460
461
462 void Thread::start(Thread* thread) {
463 // Start is different from resume in that its safety is guaranteed by context or
464 // being called from a Java method synchronized on the Thread object.
465 if (!DisableStartThread) {
466 if (thread->is_Java_thread()) {
467 // Initialize the thread state to RUNNABLE before starting this thread.
468 // Can not set it after the thread started because we do not know the
469 // exact thread state at that time. It could be in MONITOR_WAIT or
470 // in SLEEPING or some other state.
471 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
472 java_lang_Thread::RUNNABLE);
473 }
474 os::start_thread(thread);
475 }
476 }
477
478 // Enqueue a VM_Operation to do the job for us - sometime later
479 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
480 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
481 VMThread::execute(vm_stop);
482 }
483
484
485 // Check if an external suspend request has completed (or has been
486 // cancelled). Returns true if the thread is externally suspended and
487 // false otherwise.
488 //
489 // The bits parameter returns information about the code path through
490 // the routine. Useful for debugging:
491 //
492 // set in is_ext_suspend_completed():
493 // 0x00000001 - routine was entered
494 // 0x00000010 - routine return false at end
495 // 0x00000100 - thread exited (return false)
496 // 0x00000200 - suspend request cancelled (return false)
497 // 0x00000400 - thread suspended (return true)
498 // 0x00001000 - thread is in a suspend equivalent state (return true)
499 // 0x00002000 - thread is native and walkable (return true)
500 // 0x00004000 - thread is native_trans and walkable (needed retry)
501 //
502 // set in wait_for_ext_suspend_completion():
503 // 0x00010000 - routine was entered
504 // 0x00020000 - suspend request cancelled before loop (return false)
505 // 0x00040000 - thread suspended before loop (return true)
506 // 0x00080000 - suspend request cancelled in loop (return false)
507 // 0x00100000 - thread suspended in loop (return true)
508 // 0x00200000 - suspend not completed during retry loop (return false)
509
510 // Helper class for tracing suspend wait debug bits.
511 //
512 // 0x00000100 indicates that the target thread exited before it could
513 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
514 // 0x00080000 each indicate a cancelled suspend request so they don't
515 // count as wait failures either.
516 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
517
518 class TraceSuspendDebugBits : public StackObj {
519 private:
520 JavaThread * jt;
521 bool is_wait;
522 bool called_by_wait; // meaningful when !is_wait
523 uint32_t * bits;
524
525 public:
526 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
527 uint32_t *_bits) {
528 jt = _jt;
529 is_wait = _is_wait;
530 called_by_wait = _called_by_wait;
531 bits = _bits;
532 }
533
534 ~TraceSuspendDebugBits() {
535 if (!is_wait) {
536 #if 1
537 // By default, don't trace bits for is_ext_suspend_completed() calls.
538 // That trace is very chatty.
539 return;
540 #else
541 if (!called_by_wait) {
542 // If tracing for is_ext_suspend_completed() is enabled, then only
543 // trace calls to it from wait_for_ext_suspend_completion()
544 return;
545 }
546 #endif
547 }
548
549 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
550 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
551 MutexLocker ml(Threads_lock); // needed for get_thread_name()
552 ResourceMark rm;
553
554 tty->print_cr(
555 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
556 jt->get_thread_name(), *bits);
557
558 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
559 }
560 }
561 }
562 };
563 #undef DEBUG_FALSE_BITS
564
565
566 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
567 uint32_t *bits) {
568 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
569
570 bool did_trans_retry = false; // only do thread_in_native_trans retry once
571 bool do_trans_retry; // flag to force the retry
572
573 *bits |= 0x00000001;
574
575 do {
576 do_trans_retry = false;
577
578 if (is_exiting()) {
579 // Thread is in the process of exiting. This is always checked
580 // first to reduce the risk of dereferencing a freed JavaThread.
581 *bits |= 0x00000100;
582 return false;
583 }
584
585 if (!is_external_suspend()) {
586 // Suspend request is cancelled. This is always checked before
587 // is_ext_suspended() to reduce the risk of a rogue resume
588 // confusing the thread that made the suspend request.
589 *bits |= 0x00000200;
590 return false;
591 }
592
593 if (is_ext_suspended()) {
594 // thread is suspended
595 *bits |= 0x00000400;
596 return true;
597 }
598
599 // Now that we no longer do hard suspends of threads running
600 // native code, the target thread can be changing thread state
601 // while we are in this routine:
602 //
603 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
604 //
605 // We save a copy of the thread state as observed at this moment
606 // and make our decision about suspend completeness based on the
607 // copy. This closes the race where the thread state is seen as
608 // _thread_in_native_trans in the if-thread_blocked check, but is
609 // seen as _thread_blocked in if-thread_in_native_trans check.
610 JavaThreadState save_state = thread_state();
611
612 if (save_state == _thread_blocked && is_suspend_equivalent()) {
613 // If the thread's state is _thread_blocked and this blocking
614 // condition is known to be equivalent to a suspend, then we can
615 // consider the thread to be externally suspended. This means that
616 // the code that sets _thread_blocked has been modified to do
617 // self-suspension if the blocking condition releases. We also
618 // used to check for CONDVAR_WAIT here, but that is now covered by
619 // the _thread_blocked with self-suspension check.
620 //
621 // Return true since we wouldn't be here unless there was still an
622 // external suspend request.
623 *bits |= 0x00001000;
624 return true;
625 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
626 // Threads running native code will self-suspend on native==>VM/Java
627 // transitions. If its stack is walkable (should always be the case
628 // unless this function is called before the actual java_suspend()
629 // call), then the wait is done.
630 *bits |= 0x00002000;
631 return true;
632 } else if (!called_by_wait && !did_trans_retry &&
633 save_state == _thread_in_native_trans &&
634 frame_anchor()->walkable()) {
635 // The thread is transitioning from thread_in_native to another
636 // thread state. check_safepoint_and_suspend_for_native_trans()
637 // will force the thread to self-suspend. If it hasn't gotten
638 // there yet we may have caught the thread in-between the native
639 // code check above and the self-suspend. Lucky us. If we were
640 // called by wait_for_ext_suspend_completion(), then it
641 // will be doing the retries so we don't have to.
642 //
643 // Since we use the saved thread state in the if-statement above,
644 // there is a chance that the thread has already transitioned to
645 // _thread_blocked by the time we get here. In that case, we will
646 // make a single unnecessary pass through the logic below. This
647 // doesn't hurt anything since we still do the trans retry.
648
649 *bits |= 0x00004000;
650
651 // Once the thread leaves thread_in_native_trans for another
652 // thread state, we break out of this retry loop. We shouldn't
653 // need this flag to prevent us from getting back here, but
654 // sometimes paranoia is good.
655 did_trans_retry = true;
656
657 // We wait for the thread to transition to a more usable state.
658 for (int i = 1; i <= SuspendRetryCount; i++) {
659 // We used to do an "os::yield_all(i)" call here with the intention
660 // that yielding would increase on each retry. However, the parameter
661 // is ignored on Linux which means the yield didn't scale up. Waiting
662 // on the SR_lock below provides a much more predictable scale up for
663 // the delay. It also provides a simple/direct point to check for any
664 // safepoint requests from the VMThread
665
666 // temporarily drops SR_lock while doing wait with safepoint check
667 // (if we're a JavaThread - the WatcherThread can also call this)
668 // and increase delay with each retry
669 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
670
671 // check the actual thread state instead of what we saved above
672 if (thread_state() != _thread_in_native_trans) {
673 // the thread has transitioned to another thread state so
674 // try all the checks (except this one) one more time.
675 do_trans_retry = true;
676 break;
677 }
678 } // end retry loop
679
680
681 }
682 } while (do_trans_retry);
683
684 *bits |= 0x00000010;
685 return false;
686 }
687
688 // Wait for an external suspend request to complete (or be cancelled).
689 // Returns true if the thread is externally suspended and false otherwise.
690 //
691 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
692 uint32_t *bits) {
693 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
694 false /* !called_by_wait */, bits);
695
696 // local flag copies to minimize SR_lock hold time
697 bool is_suspended;
698 bool pending;
699 uint32_t reset_bits;
700
701 // set a marker so is_ext_suspend_completed() knows we are the caller
702 *bits |= 0x00010000;
703
704 // We use reset_bits to reinitialize the bits value at the top of
705 // each retry loop. This allows the caller to make use of any
706 // unused bits for their own marking purposes.
707 reset_bits = *bits;
708
709 {
710 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
711 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
712 delay, bits);
713 pending = is_external_suspend();
714 }
715 // must release SR_lock to allow suspension to complete
716
717 if (!pending) {
718 // A cancelled suspend request is the only false return from
719 // is_ext_suspend_completed() that keeps us from entering the
720 // retry loop.
721 *bits |= 0x00020000;
722 return false;
723 }
724
725 if (is_suspended) {
726 *bits |= 0x00040000;
727 return true;
728 }
729
730 for (int i = 1; i <= retries; i++) {
731 *bits = reset_bits; // reinit to only track last retry
732
733 // We used to do an "os::yield_all(i)" call here with the intention
734 // that yielding would increase on each retry. However, the parameter
735 // is ignored on Linux which means the yield didn't scale up. Waiting
736 // on the SR_lock below provides a much more predictable scale up for
737 // the delay. It also provides a simple/direct point to check for any
738 // safepoint requests from the VMThread
739
740 {
741 MutexLocker ml(SR_lock());
742 // wait with safepoint check (if we're a JavaThread - the WatcherThread
743 // can also call this) and increase delay with each retry
744 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
745
746 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
747 delay, bits);
748
749 // It is possible for the external suspend request to be cancelled
750 // (by a resume) before the actual suspend operation is completed.
751 // Refresh our local copy to see if we still need to wait.
752 pending = is_external_suspend();
753 }
754
755 if (!pending) {
756 // A cancelled suspend request is the only false return from
757 // is_ext_suspend_completed() that keeps us from staying in the
758 // retry loop.
759 *bits |= 0x00080000;
760 return false;
761 }
762
763 if (is_suspended) {
764 *bits |= 0x00100000;
765 return true;
766 }
767 } // end retry loop
768
769 // thread did not suspend after all our retries
770 *bits |= 0x00200000;
771 return false;
772 }
773
774 // Called from API entry points which perform stack walking. If the
775 // associated JavaThread is the current thread, then wait_for_suspend
776 // is not used. Otherwise, it determines if we should wait for the
777 // "other" thread to complete external suspension. (NOTE: in future
778 // releases the suspension mechanism should be reimplemented so this
779 // is not necessary.)
780 //
781 bool
782 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
783 if (this != JavaThread::current()) {
784 // "other" threads require special handling.
785 if (wait_for_suspend) {
786 // We are allowed to wait for the external suspend to complete
787 // so give the other thread a chance to get suspended.
788 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
789 SuspendRetryDelay, bits)) {
790 // Didn't make it so let the caller know.
791 return false;
792 }
793 }
794 // We aren't allowed to wait for the external suspend to complete
795 // so if the other thread isn't externally suspended we need to
796 // let the caller know.
797 else if (!is_ext_suspend_completed_with_lock(bits)) {
798 return false;
799 }
800 }
801
802 return true;
803 }
804
805 #ifndef PRODUCT
806 void JavaThread::record_jump(address target, address instr, const char* file,
807 int line) {
808
809 // This should not need to be atomic as the only way for simultaneous
810 // updates is via interrupts. Even then this should be rare or non-existent
811 // and we don't care that much anyway.
812
813 int index = _jmp_ring_index;
814 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
815 _jmp_ring[index]._target = (intptr_t) target;
816 _jmp_ring[index]._instruction = (intptr_t) instr;
817 _jmp_ring[index]._file = file;
818 _jmp_ring[index]._line = line;
819 }
820 #endif // PRODUCT
821
822 void Thread::interrupt(Thread* thread) {
823 debug_only(check_for_dangling_thread_pointer(thread);)
824 os::interrupt(thread);
825 }
826
827 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
828 debug_only(check_for_dangling_thread_pointer(thread);)
829 // Note: If clear_interrupted==false, this simply fetches and
830 // returns the value of the field osthread()->interrupted().
831 return os::is_interrupted(thread, clear_interrupted);
832 }
833
834
835 // GC Support
836 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
837 int thread_parity = _oops_do_parity;
838 if (thread_parity != strong_roots_parity) {
839 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
840 if (res == thread_parity) {
841 return true;
842 } else {
843 guarantee(res == strong_roots_parity, "Or else what?");
844 return false;
845 }
846 }
847 return false;
848 }
849
850 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
851 active_handles()->oops_do(f);
852 // Do oop for ThreadShadow
853 f->do_oop((oop*)&_pending_exception);
854 handle_area()->oops_do(f);
855
856 if (MonitorInUseLists) {
857 // When using thread local monitor lists, we scan them here,
858 // and the remaining global monitors in ObjectSynchronizer::oops_do().
859 ObjectSynchronizer::thread_local_used_oops_do(this, f);
860 }
861 }
862
863 void Thread::metadata_handles_do(void f(Metadata*)) {
864 // Only walk the Handles in Thread.
865 if (metadata_handles() != NULL) {
866 for (int i = 0; i< metadata_handles()->length(); i++) {
867 f(metadata_handles()->at(i));
868 }
869 }
870 }
871
872 void Thread::print_on(outputStream* st) const {
873 // get_priority assumes osthread initialized
874 if (osthread() != NULL) {
875 int os_prio;
876 if (os::get_native_priority(this, &os_prio) == OS_OK) {
877 st->print("os_prio=%d ", os_prio);
878 }
879 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
880 osthread()->print_on(st);
881 }
882 ThreadsSMRSupport::print_info_on(this, st);
883 st->print(" ");
884 debug_only(if (WizardMode) print_owned_locks_on(st);)
885 }
886
887 // Thread::print_on_error() is called by fatal error handler. Don't use
888 // any lock or allocate memory.
889 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
890 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
891
892 if (is_VM_thread()) { st->print("VMThread"); }
893 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
894 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
895 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
896 else { st->print("Thread"); }
897
898 if (is_Named_thread()) {
899 st->print(" \"%s\"", name());
900 }
901
902 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
903 p2i(stack_end()), p2i(stack_base()));
904
905 if (osthread()) {
906 st->print(" [id=%d]", osthread()->thread_id());
907 }
908
909 ThreadsSMRSupport::print_info_on(this, st);
910 }
911
912 void Thread::print_value_on(outputStream* st) const {
913 if (is_Named_thread()) {
914 st->print(" \"%s\" ", name());
915 }
916 st->print(INTPTR_FORMAT, p2i(this)); // print address
917 }
918
919 #ifdef ASSERT
920 void Thread::print_owned_locks_on(outputStream* st) const {
921 Monitor *cur = _owned_locks;
922 if (cur == NULL) {
923 st->print(" (no locks) ");
924 } else {
925 st->print_cr(" Locks owned:");
926 while (cur) {
927 cur->print_on(st);
928 cur = cur->next();
929 }
930 }
931 }
932
933 static int ref_use_count = 0;
934
935 bool Thread::owns_locks_but_compiled_lock() const {
936 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
937 if (cur != Compile_lock) return true;
938 }
939 return false;
940 }
941
942
943 #endif
944
945 #ifndef PRODUCT
946
947 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
948 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
949 // no threads which allow_vm_block's are held
950 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
951 // Check if current thread is allowed to block at a safepoint
952 if (!(_allow_safepoint_count == 0)) {
953 fatal("Possible safepoint reached by thread that does not allow it");
954 }
955 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
956 fatal("LEAF method calling lock?");
957 }
958
959 #ifdef ASSERT
960 if (potential_vm_operation && is_Java_thread()
961 && !Universe::is_bootstrapping()) {
962 // Make sure we do not hold any locks that the VM thread also uses.
963 // This could potentially lead to deadlocks
964 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
965 // Threads_lock is special, since the safepoint synchronization will not start before this is
966 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
967 // since it is used to transfer control between JavaThreads and the VMThread
968 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
969 if ((cur->allow_vm_block() &&
970 cur != Threads_lock &&
971 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
972 cur != VMOperationRequest_lock &&
973 cur != VMOperationQueue_lock) ||
974 cur->rank() == Mutex::special) {
975 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
976 }
977 }
978 }
979
980 if (GCALotAtAllSafepoints) {
981 // We could enter a safepoint here and thus have a gc
982 InterfaceSupport::check_gc_alot();
983 }
984 #endif
985 }
986 #endif
987
988 bool Thread::is_in_stack(address adr) const {
989 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
990 address end = os::current_stack_pointer();
991 // Allow non Java threads to call this without stack_base
992 if (_stack_base == NULL) return true;
993 if (stack_base() >= adr && adr >= end) return true;
994
995 return false;
996 }
997
998 bool Thread::is_in_usable_stack(address adr) const {
999 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1000 size_t usable_stack_size = _stack_size - stack_guard_size;
1001
1002 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1003 }
1004
1005
1006 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1007 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1008 // used for compilation in the future. If that change is made, the need for these methods
1009 // should be revisited, and they should be removed if possible.
1010
1011 bool Thread::is_lock_owned(address adr) const {
1012 return on_local_stack(adr);
1013 }
1014
1015 bool Thread::set_as_starting_thread() {
1016 // NOTE: this must be called inside the main thread.
1017 return os::create_main_thread((JavaThread*)this);
1018 }
1019
1020 static void initialize_class(Symbol* class_name, TRAPS) {
1021 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1022 InstanceKlass::cast(klass)->initialize(CHECK);
1023 }
1024
1025
1026 // Creates the initial ThreadGroup
1027 static Handle create_initial_thread_group(TRAPS) {
1028 Handle system_instance = JavaCalls::construct_new_instance(
1029 SystemDictionary::ThreadGroup_klass(),
1030 vmSymbols::void_method_signature(),
1031 CHECK_NH);
1032 Universe::set_system_thread_group(system_instance());
1033
1034 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1035 Handle main_instance = JavaCalls::construct_new_instance(
1036 SystemDictionary::ThreadGroup_klass(),
1037 vmSymbols::threadgroup_string_void_signature(),
1038 system_instance,
1039 string,
1040 CHECK_NH);
1041 return main_instance;
1042 }
1043
1044 // Creates the initial Thread
1045 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1046 TRAPS) {
1047 InstanceKlass* ik = SystemDictionary::Thread_klass();
1048 assert(ik->is_initialized(), "must be");
1049 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1050
1051 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1052 // constructor calls Thread.current(), which must be set here for the
1053 // initial thread.
1054 java_lang_Thread::set_thread(thread_oop(), thread);
1055 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1056 thread->set_threadObj(thread_oop());
1057
1058 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1059
1060 JavaValue result(T_VOID);
1061 JavaCalls::call_special(&result, thread_oop,
1062 ik,
1063 vmSymbols::object_initializer_name(),
1064 vmSymbols::threadgroup_string_void_signature(),
1065 thread_group,
1066 string,
1067 CHECK_NULL);
1068 return thread_oop();
1069 }
1070
1071 char java_runtime_name[128] = "";
1072 char java_runtime_version[128] = "";
1073
1074 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1075 static const char* get_java_runtime_name(TRAPS) {
1076 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1077 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1078 fieldDescriptor fd;
1079 bool found = k != NULL &&
1080 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1081 vmSymbols::string_signature(), &fd);
1082 if (found) {
1083 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1084 if (name_oop == NULL) {
1085 return NULL;
1086 }
1087 const char* name = java_lang_String::as_utf8_string(name_oop,
1088 java_runtime_name,
1089 sizeof(java_runtime_name));
1090 return name;
1091 } else {
1092 return NULL;
1093 }
1094 }
1095
1096 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1097 static const char* get_java_runtime_version(TRAPS) {
1098 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1099 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1100 fieldDescriptor fd;
1101 bool found = k != NULL &&
1102 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1103 vmSymbols::string_signature(), &fd);
1104 if (found) {
1105 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1106 if (name_oop == NULL) {
1107 return NULL;
1108 }
1109 const char* name = java_lang_String::as_utf8_string(name_oop,
1110 java_runtime_version,
1111 sizeof(java_runtime_version));
1112 return name;
1113 } else {
1114 return NULL;
1115 }
1116 }
1117
1118 // General purpose hook into Java code, run once when the VM is initialized.
1119 // The Java library method itself may be changed independently from the VM.
1120 static void call_postVMInitHook(TRAPS) {
1121 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1122 if (klass != NULL) {
1123 JavaValue result(T_VOID);
1124 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1125 vmSymbols::void_method_signature(),
1126 CHECK);
1127 }
1128 }
1129
1130 static void reset_vm_info_property(TRAPS) {
1131 // the vm info string
1132 ResourceMark rm(THREAD);
1133 const char *vm_info = VM_Version::vm_info_string();
1134
1135 // java.lang.System class
1136 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1137
1138 // setProperty arguments
1139 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1140 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1141
1142 // return value
1143 JavaValue r(T_OBJECT);
1144
1145 // public static String setProperty(String key, String value);
1146 JavaCalls::call_static(&r,
1147 klass,
1148 vmSymbols::setProperty_name(),
1149 vmSymbols::string_string_string_signature(),
1150 key_str,
1151 value_str,
1152 CHECK);
1153 }
1154
1155
1156 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1157 bool daemon, TRAPS) {
1158 assert(thread_group.not_null(), "thread group should be specified");
1159 assert(threadObj() == NULL, "should only create Java thread object once");
1160
1161 InstanceKlass* ik = SystemDictionary::Thread_klass();
1162 assert(ik->is_initialized(), "must be");
1163 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1164
1165 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1166 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1167 // constructor calls Thread.current(), which must be set here.
1168 java_lang_Thread::set_thread(thread_oop(), this);
1169 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1170 set_threadObj(thread_oop());
1171
1172 JavaValue result(T_VOID);
1173 if (thread_name != NULL) {
1174 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1175 // Thread gets assigned specified name and null target
1176 JavaCalls::call_special(&result,
1177 thread_oop,
1178 ik,
1179 vmSymbols::object_initializer_name(),
1180 vmSymbols::threadgroup_string_void_signature(),
1181 thread_group,
1182 name,
1183 THREAD);
1184 } else {
1185 // Thread gets assigned name "Thread-nnn" and null target
1186 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1187 JavaCalls::call_special(&result,
1188 thread_oop,
1189 ik,
1190 vmSymbols::object_initializer_name(),
1191 vmSymbols::threadgroup_runnable_void_signature(),
1192 thread_group,
1193 Handle(),
1194 THREAD);
1195 }
1196
1197
1198 if (daemon) {
1199 java_lang_Thread::set_daemon(thread_oop());
1200 }
1201
1202 if (HAS_PENDING_EXCEPTION) {
1203 return;
1204 }
1205
1206 Klass* group = SystemDictionary::ThreadGroup_klass();
1207 Handle threadObj(THREAD, this->threadObj());
1208
1209 JavaCalls::call_special(&result,
1210 thread_group,
1211 group,
1212 vmSymbols::add_method_name(),
1213 vmSymbols::thread_void_signature(),
1214 threadObj, // Arg 1
1215 THREAD);
1216 }
1217
1218 // NamedThread -- non-JavaThread subclasses with multiple
1219 // uniquely named instances should derive from this.
1220 NamedThread::NamedThread() : Thread() {
1221 _name = NULL;
1222 _processed_thread = NULL;
1223 _gc_id = GCId::undefined();
1224 }
1225
1226 NamedThread::~NamedThread() {
1227 if (_name != NULL) {
1228 FREE_C_HEAP_ARRAY(char, _name);
1229 _name = NULL;
1230 }
1231 }
1232
1233 void NamedThread::set_name(const char* format, ...) {
1234 guarantee(_name == NULL, "Only get to set name once.");
1235 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1236 guarantee(_name != NULL, "alloc failure");
1237 va_list ap;
1238 va_start(ap, format);
1239 jio_vsnprintf(_name, max_name_len, format, ap);
1240 va_end(ap);
1241 }
1242
1243 void NamedThread::initialize_named_thread() {
1244 set_native_thread_name(name());
1245 }
1246
1247 void NamedThread::print_on(outputStream* st) const {
1248 st->print("\"%s\" ", name());
1249 Thread::print_on(st);
1250 st->cr();
1251 }
1252
1253
1254 // ======= WatcherThread ========
1255
1256 // The watcher thread exists to simulate timer interrupts. It should
1257 // be replaced by an abstraction over whatever native support for
1258 // timer interrupts exists on the platform.
1259
1260 WatcherThread* WatcherThread::_watcher_thread = NULL;
1261 bool WatcherThread::_startable = false;
1262 volatile bool WatcherThread::_should_terminate = false;
1263
1264 WatcherThread::WatcherThread() : Thread() {
1265 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1266 if (os::create_thread(this, os::watcher_thread)) {
1267 _watcher_thread = this;
1268
1269 // Set the watcher thread to the highest OS priority which should not be
1270 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1271 // is created. The only normal thread using this priority is the reference
1272 // handler thread, which runs for very short intervals only.
1273 // If the VMThread's priority is not lower than the WatcherThread profiling
1274 // will be inaccurate.
1275 os::set_priority(this, MaxPriority);
1276 if (!DisableStartThread) {
1277 os::start_thread(this);
1278 }
1279 }
1280 }
1281
1282 int WatcherThread::sleep() const {
1283 // The WatcherThread does not participate in the safepoint protocol
1284 // for the PeriodicTask_lock because it is not a JavaThread.
1285 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1286
1287 if (_should_terminate) {
1288 // check for termination before we do any housekeeping or wait
1289 return 0; // we did not sleep.
1290 }
1291
1292 // remaining will be zero if there are no tasks,
1293 // causing the WatcherThread to sleep until a task is
1294 // enrolled
1295 int remaining = PeriodicTask::time_to_wait();
1296 int time_slept = 0;
1297
1298 // we expect this to timeout - we only ever get unparked when
1299 // we should terminate or when a new task has been enrolled
1300 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1301
1302 jlong time_before_loop = os::javaTimeNanos();
1303
1304 while (true) {
1305 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1306 remaining);
1307 jlong now = os::javaTimeNanos();
1308
1309 if (remaining == 0) {
1310 // if we didn't have any tasks we could have waited for a long time
1311 // consider the time_slept zero and reset time_before_loop
1312 time_slept = 0;
1313 time_before_loop = now;
1314 } else {
1315 // need to recalculate since we might have new tasks in _tasks
1316 time_slept = (int) ((now - time_before_loop) / 1000000);
1317 }
1318
1319 // Change to task list or spurious wakeup of some kind
1320 if (timedout || _should_terminate) {
1321 break;
1322 }
1323
1324 remaining = PeriodicTask::time_to_wait();
1325 if (remaining == 0) {
1326 // Last task was just disenrolled so loop around and wait until
1327 // another task gets enrolled
1328 continue;
1329 }
1330
1331 remaining -= time_slept;
1332 if (remaining <= 0) {
1333 break;
1334 }
1335 }
1336
1337 return time_slept;
1338 }
1339
1340 void WatcherThread::run() {
1341 assert(this == watcher_thread(), "just checking");
1342
1343 this->record_stack_base_and_size();
1344 this->set_native_thread_name(this->name());
1345 this->set_active_handles(JNIHandleBlock::allocate_block());
1346 while (true) {
1347 assert(watcher_thread() == Thread::current(), "thread consistency check");
1348 assert(watcher_thread() == this, "thread consistency check");
1349
1350 // Calculate how long it'll be until the next PeriodicTask work
1351 // should be done, and sleep that amount of time.
1352 int time_waited = sleep();
1353
1354 if (VMError::is_error_reported()) {
1355 // A fatal error has happened, the error handler(VMError::report_and_die)
1356 // should abort JVM after creating an error log file. However in some
1357 // rare cases, the error handler itself might deadlock. Here periodically
1358 // check for error reporting timeouts, and if it happens, just proceed to
1359 // abort the VM.
1360
1361 // This code is in WatcherThread because WatcherThread wakes up
1362 // periodically so the fatal error handler doesn't need to do anything;
1363 // also because the WatcherThread is less likely to crash than other
1364 // threads.
1365
1366 for (;;) {
1367 // Note: we use naked sleep in this loop because we want to avoid using
1368 // any kind of VM infrastructure which may be broken at this point.
1369 if (VMError::check_timeout()) {
1370 // We hit error reporting timeout. Error reporting was interrupted and
1371 // will be wrapping things up now (closing files etc). Give it some more
1372 // time, then quit the VM.
1373 os::naked_short_sleep(200);
1374 // Print a message to stderr.
1375 fdStream err(defaultStream::output_fd());
1376 err.print_raw_cr("# [ timer expired, abort... ]");
1377 // skip atexit/vm_exit/vm_abort hooks
1378 os::die();
1379 }
1380
1381 // Wait a second, then recheck for timeout.
1382 os::naked_short_sleep(999);
1383 }
1384 }
1385
1386 if (_should_terminate) {
1387 // check for termination before posting the next tick
1388 break;
1389 }
1390
1391 PeriodicTask::real_time_tick(time_waited);
1392 }
1393
1394 // Signal that it is terminated
1395 {
1396 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1397 _watcher_thread = NULL;
1398 Terminator_lock->notify();
1399 }
1400 }
1401
1402 void WatcherThread::start() {
1403 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1404
1405 if (watcher_thread() == NULL && _startable) {
1406 _should_terminate = false;
1407 // Create the single instance of WatcherThread
1408 new WatcherThread();
1409 }
1410 }
1411
1412 void WatcherThread::make_startable() {
1413 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1414 _startable = true;
1415 }
1416
1417 void WatcherThread::stop() {
1418 {
1419 // Follow normal safepoint aware lock enter protocol since the
1420 // WatcherThread is stopped by another JavaThread.
1421 MutexLocker ml(PeriodicTask_lock);
1422 _should_terminate = true;
1423
1424 WatcherThread* watcher = watcher_thread();
1425 if (watcher != NULL) {
1426 // unpark the WatcherThread so it can see that it should terminate
1427 watcher->unpark();
1428 }
1429 }
1430
1431 MutexLocker mu(Terminator_lock);
1432
1433 while (watcher_thread() != NULL) {
1434 // This wait should make safepoint checks, wait without a timeout,
1435 // and wait as a suspend-equivalent condition.
1436 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1437 Mutex::_as_suspend_equivalent_flag);
1438 }
1439 }
1440
1441 void WatcherThread::unpark() {
1442 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1443 PeriodicTask_lock->notify();
1444 }
1445
1446 void WatcherThread::print_on(outputStream* st) const {
1447 st->print("\"%s\" ", name());
1448 Thread::print_on(st);
1449 st->cr();
1450 }
1451
1452 // ======= JavaThread ========
1453
1454 #if INCLUDE_JVMCI
1455
1456 jlong* JavaThread::_jvmci_old_thread_counters;
1457
1458 bool jvmci_counters_include(JavaThread* thread) {
1459 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1460 }
1461
1462 void JavaThread::collect_counters(typeArrayOop array) {
1463 if (JVMCICounterSize > 0) {
1464 JavaThreadIteratorWithHandle jtiwh;
1465 for (int i = 0; i < array->length(); i++) {
1466 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1467 }
1468 for (; JavaThread *tp = jtiwh.next(); ) {
1469 if (jvmci_counters_include(tp)) {
1470 for (int i = 0; i < array->length(); i++) {
1471 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1472 }
1473 }
1474 }
1475 }
1476 }
1477
1478 #endif // INCLUDE_JVMCI
1479
1480 // A JavaThread is a normal Java thread
1481
1482 void JavaThread::initialize() {
1483 // Initialize fields
1484
1485 set_saved_exception_pc(NULL);
1486 set_threadObj(NULL);
1487 _anchor.clear();
1488 set_entry_point(NULL);
1489 set_jni_functions(jni_functions());
1490 set_callee_target(NULL);
1491 set_vm_result(NULL);
1492 set_vm_result_2(NULL);
1493 set_vframe_array_head(NULL);
1494 set_vframe_array_last(NULL);
1495 set_deferred_locals(NULL);
1496 set_deopt_mark(NULL);
1497 set_deopt_compiled_method(NULL);
1498 clear_must_deopt_id();
1499 set_monitor_chunks(NULL);
1500 set_next(NULL);
1501 _on_thread_list = false;
1502 set_thread_state(_thread_new);
1503 _terminated = _not_terminated;
1504 _privileged_stack_top = NULL;
1505 _array_for_gc = NULL;
1506 _suspend_equivalent = false;
1507 _in_deopt_handler = 0;
1508 _doing_unsafe_access = false;
1509 _stack_guard_state = stack_guard_unused;
1510 #if INCLUDE_JVMCI
1511 _pending_monitorenter = false;
1512 _pending_deoptimization = -1;
1513 _pending_failed_speculation = NULL;
1514 _pending_transfer_to_interpreter = false;
1515 _adjusting_comp_level = false;
1516 _jvmci._alternate_call_target = NULL;
1517 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1518 if (JVMCICounterSize > 0) {
1519 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1520 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1521 } else {
1522 _jvmci_counters = NULL;
1523 }
1524 #endif // INCLUDE_JVMCI
1525 _reserved_stack_activation = NULL; // stack base not known yet
1526 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1527 _exception_pc = 0;
1528 _exception_handler_pc = 0;
1529 _is_method_handle_return = 0;
1530 _jvmti_thread_state= NULL;
1531 _should_post_on_exceptions_flag = JNI_FALSE;
1532 _jvmti_get_loaded_classes_closure = NULL;
1533 _interp_only_mode = 0;
1534 _special_runtime_exit_condition = _no_async_condition;
1535 _pending_async_exception = NULL;
1536 _thread_stat = NULL;
1537 _thread_stat = new ThreadStatistics();
1538 _blocked_on_compilation = false;
1539 _jni_active_critical = 0;
1540 _pending_jni_exception_check_fn = NULL;
1541 _do_not_unlock_if_synchronized = false;
1542 _cached_monitor_info = NULL;
1543 _parker = Parker::Allocate(this);
1544
1545 #ifndef PRODUCT
1546 _jmp_ring_index = 0;
1547 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1548 record_jump(NULL, NULL, NULL, 0);
1549 }
1550 #endif // PRODUCT
1551
1552 // Setup safepoint state info for this thread
1553 ThreadSafepointState::create(this);
1554
1555 debug_only(_java_call_counter = 0);
1556
1557 // JVMTI PopFrame support
1558 _popframe_condition = popframe_inactive;
1559 _popframe_preserved_args = NULL;
1560 _popframe_preserved_args_size = 0;
1561 _frames_to_pop_failed_realloc = 0;
1562
1563 if (SafepointMechanism::uses_thread_local_poll()) {
1564 SafepointMechanism::initialize_header(this);
1565 }
1566
1567 pd_initialize();
1568 }
1569
1570 JavaThread::JavaThread(bool is_attaching_via_jni) :
1571 Thread() {
1572 initialize();
1573 if (is_attaching_via_jni) {
1574 _jni_attach_state = _attaching_via_jni;
1575 } else {
1576 _jni_attach_state = _not_attaching_via_jni;
1577 }
1578 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1579 }
1580
1581 bool JavaThread::reguard_stack(address cur_sp) {
1582 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1583 && _stack_guard_state != stack_guard_reserved_disabled) {
1584 return true; // Stack already guarded or guard pages not needed.
1585 }
1586
1587 if (register_stack_overflow()) {
1588 // For those architectures which have separate register and
1589 // memory stacks, we must check the register stack to see if
1590 // it has overflowed.
1591 return false;
1592 }
1593
1594 // Java code never executes within the yellow zone: the latter is only
1595 // there to provoke an exception during stack banging. If java code
1596 // is executing there, either StackShadowPages should be larger, or
1597 // some exception code in c1, c2 or the interpreter isn't unwinding
1598 // when it should.
1599 guarantee(cur_sp > stack_reserved_zone_base(),
1600 "not enough space to reguard - increase StackShadowPages");
1601 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1602 enable_stack_yellow_reserved_zone();
1603 if (reserved_stack_activation() != stack_base()) {
1604 set_reserved_stack_activation(stack_base());
1605 }
1606 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1607 set_reserved_stack_activation(stack_base());
1608 enable_stack_reserved_zone();
1609 }
1610 return true;
1611 }
1612
1613 bool JavaThread::reguard_stack(void) {
1614 return reguard_stack(os::current_stack_pointer());
1615 }
1616
1617
1618 void JavaThread::block_if_vm_exited() {
1619 if (_terminated == _vm_exited) {
1620 // _vm_exited is set at safepoint, and Threads_lock is never released
1621 // we will block here forever
1622 Threads_lock->lock_without_safepoint_check();
1623 ShouldNotReachHere();
1624 }
1625 }
1626
1627
1628 // Remove this ifdef when C1 is ported to the compiler interface.
1629 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1630 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1631
1632 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1633 Thread() {
1634 initialize();
1635 _jni_attach_state = _not_attaching_via_jni;
1636 set_entry_point(entry_point);
1637 // Create the native thread itself.
1638 // %note runtime_23
1639 os::ThreadType thr_type = os::java_thread;
1640 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1641 os::java_thread;
1642 os::create_thread(this, thr_type, stack_sz);
1643 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1644 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1645 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1646 // the exception consists of creating the exception object & initializing it, initialization
1647 // will leave the VM via a JavaCall and then all locks must be unlocked).
1648 //
1649 // The thread is still suspended when we reach here. Thread must be explicit started
1650 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1651 // by calling Threads:add. The reason why this is not done here, is because the thread
1652 // object must be fully initialized (take a look at JVM_Start)
1653 }
1654
1655 JavaThread::~JavaThread() {
1656
1657 // JSR166 -- return the parker to the free list
1658 Parker::Release(_parker);
1659 _parker = NULL;
1660
1661 // Free any remaining previous UnrollBlock
1662 vframeArray* old_array = vframe_array_last();
1663
1664 if (old_array != NULL) {
1665 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1666 old_array->set_unroll_block(NULL);
1667 delete old_info;
1668 delete old_array;
1669 }
1670
1671 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1672 if (deferred != NULL) {
1673 // This can only happen if thread is destroyed before deoptimization occurs.
1674 assert(deferred->length() != 0, "empty array!");
1675 do {
1676 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1677 deferred->remove_at(0);
1678 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1679 delete dlv;
1680 } while (deferred->length() != 0);
1681 delete deferred;
1682 }
1683
1684 // All Java related clean up happens in exit
1685 ThreadSafepointState::destroy(this);
1686 if (_thread_stat != NULL) delete _thread_stat;
1687
1688 #if INCLUDE_JVMCI
1689 if (JVMCICounterSize > 0) {
1690 if (jvmci_counters_include(this)) {
1691 for (int i = 0; i < JVMCICounterSize; i++) {
1692 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1693 }
1694 }
1695 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1696 }
1697 #endif // INCLUDE_JVMCI
1698 }
1699
1700
1701 // The first routine called by a new Java thread
1702 void JavaThread::run() {
1703 // initialize thread-local alloc buffer related fields
1704 this->initialize_tlab();
1705
1706 // used to test validity of stack trace backs
1707 this->record_base_of_stack_pointer();
1708
1709 // Record real stack base and size.
1710 this->record_stack_base_and_size();
1711
1712 this->create_stack_guard_pages();
1713
1714 this->cache_global_variables();
1715
1716 // Thread is now sufficient initialized to be handled by the safepoint code as being
1717 // in the VM. Change thread state from _thread_new to _thread_in_vm
1718 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1719
1720 assert(JavaThread::current() == this, "sanity check");
1721 assert(!Thread::current()->owns_locks(), "sanity check");
1722
1723 DTRACE_THREAD_PROBE(start, this);
1724
1725 // This operation might block. We call that after all safepoint checks for a new thread has
1726 // been completed.
1727 this->set_active_handles(JNIHandleBlock::allocate_block());
1728
1729 if (JvmtiExport::should_post_thread_life()) {
1730 JvmtiExport::post_thread_start(this);
1731 }
1732
1733 EventThreadStart event;
1734 if (event.should_commit()) {
1735 event.set_thread(JFR_THREAD_ID(this));
1736 event.commit();
1737 }
1738
1739 // We call another function to do the rest so we are sure that the stack addresses used
1740 // from there will be lower than the stack base just computed
1741 thread_main_inner();
1742
1743 // Note, thread is no longer valid at this point!
1744 }
1745
1746
1747 void JavaThread::thread_main_inner() {
1748 assert(JavaThread::current() == this, "sanity check");
1749 assert(this->threadObj() != NULL, "just checking");
1750
1751 // Execute thread entry point unless this thread has a pending exception
1752 // or has been stopped before starting.
1753 // Note: Due to JVM_StopThread we can have pending exceptions already!
1754 if (!this->has_pending_exception() &&
1755 !java_lang_Thread::is_stillborn(this->threadObj())) {
1756 {
1757 ResourceMark rm(this);
1758 this->set_native_thread_name(this->get_thread_name());
1759 }
1760 HandleMark hm(this);
1761 this->entry_point()(this, this);
1762 }
1763
1764 DTRACE_THREAD_PROBE(stop, this);
1765
1766 this->exit(false);
1767 this->smr_delete();
1768 }
1769
1770
1771 static void ensure_join(JavaThread* thread) {
1772 // We do not need to grab the Threads_lock, since we are operating on ourself.
1773 Handle threadObj(thread, thread->threadObj());
1774 assert(threadObj.not_null(), "java thread object must exist");
1775 ObjectLocker lock(threadObj, thread);
1776 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1777 thread->clear_pending_exception();
1778 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1779 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1780 // Clear the native thread instance - this makes isAlive return false and allows the join()
1781 // to complete once we've done the notify_all below
1782 java_lang_Thread::set_thread(threadObj(), NULL);
1783 lock.notify_all(thread);
1784 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1785 thread->clear_pending_exception();
1786 }
1787
1788
1789 // For any new cleanup additions, please check to see if they need to be applied to
1790 // cleanup_failed_attach_current_thread as well.
1791 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1792 assert(this == JavaThread::current(), "thread consistency check");
1793
1794 elapsedTimer _timer_exit_phase1;
1795 elapsedTimer _timer_exit_phase2;
1796 elapsedTimer _timer_exit_phase3;
1797 elapsedTimer _timer_exit_phase4;
1798
1799 if (log_is_enabled(Debug, os, thread, timer)) {
1800 _timer_exit_phase1.start();
1801 }
1802
1803 HandleMark hm(this);
1804 Handle uncaught_exception(this, this->pending_exception());
1805 this->clear_pending_exception();
1806 Handle threadObj(this, this->threadObj());
1807 assert(threadObj.not_null(), "Java thread object should be created");
1808
1809 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1810 {
1811 EXCEPTION_MARK;
1812
1813 CLEAR_PENDING_EXCEPTION;
1814 }
1815 if (!destroy_vm) {
1816 if (uncaught_exception.not_null()) {
1817 EXCEPTION_MARK;
1818 // Call method Thread.dispatchUncaughtException().
1819 Klass* thread_klass = SystemDictionary::Thread_klass();
1820 JavaValue result(T_VOID);
1821 JavaCalls::call_virtual(&result,
1822 threadObj, thread_klass,
1823 vmSymbols::dispatchUncaughtException_name(),
1824 vmSymbols::throwable_void_signature(),
1825 uncaught_exception,
1826 THREAD);
1827 if (HAS_PENDING_EXCEPTION) {
1828 ResourceMark rm(this);
1829 jio_fprintf(defaultStream::error_stream(),
1830 "\nException: %s thrown from the UncaughtExceptionHandler"
1831 " in thread \"%s\"\n",
1832 pending_exception()->klass()->external_name(),
1833 get_thread_name());
1834 CLEAR_PENDING_EXCEPTION;
1835 }
1836 }
1837
1838 // Called before the java thread exit since we want to read info
1839 // from java_lang_Thread object
1840 EventThreadEnd event;
1841 if (event.should_commit()) {
1842 event.set_thread(JFR_THREAD_ID(this));
1843 event.commit();
1844 }
1845
1846 // Call after last event on thread
1847 JFR_ONLY(Jfr::on_thread_exit(this);)
1848
1849 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1850 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1851 // is deprecated anyhow.
1852 if (!is_Compiler_thread()) {
1853 int count = 3;
1854 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1855 EXCEPTION_MARK;
1856 JavaValue result(T_VOID);
1857 Klass* thread_klass = SystemDictionary::Thread_klass();
1858 JavaCalls::call_virtual(&result,
1859 threadObj, thread_klass,
1860 vmSymbols::exit_method_name(),
1861 vmSymbols::void_method_signature(),
1862 THREAD);
1863 CLEAR_PENDING_EXCEPTION;
1864 }
1865 }
1866 // notify JVMTI
1867 if (JvmtiExport::should_post_thread_life()) {
1868 JvmtiExport::post_thread_end(this);
1869 }
1870
1871 // We have notified the agents that we are exiting, before we go on,
1872 // we must check for a pending external suspend request and honor it
1873 // in order to not surprise the thread that made the suspend request.
1874 while (true) {
1875 {
1876 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1877 if (!is_external_suspend()) {
1878 set_terminated(_thread_exiting);
1879 ThreadService::current_thread_exiting(this);
1880 break;
1881 }
1882 // Implied else:
1883 // Things get a little tricky here. We have a pending external
1884 // suspend request, but we are holding the SR_lock so we
1885 // can't just self-suspend. So we temporarily drop the lock
1886 // and then self-suspend.
1887 }
1888
1889 ThreadBlockInVM tbivm(this);
1890 java_suspend_self();
1891
1892 // We're done with this suspend request, but we have to loop around
1893 // and check again. Eventually we will get SR_lock without a pending
1894 // external suspend request and will be able to mark ourselves as
1895 // exiting.
1896 }
1897 // no more external suspends are allowed at this point
1898 } else {
1899 // before_exit() has already posted JVMTI THREAD_END events
1900 }
1901
1902 if (log_is_enabled(Debug, os, thread, timer)) {
1903 _timer_exit_phase1.stop();
1904 _timer_exit_phase2.start();
1905 }
1906 // Notify waiters on thread object. This has to be done after exit() is called
1907 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1908 // group should have the destroyed bit set before waiters are notified).
1909 ensure_join(this);
1910 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1911
1912 if (log_is_enabled(Debug, os, thread, timer)) {
1913 _timer_exit_phase2.stop();
1914 _timer_exit_phase3.start();
1915 }
1916 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1917 // held by this thread must be released. The spec does not distinguish
1918 // between JNI-acquired and regular Java monitors. We can only see
1919 // regular Java monitors here if monitor enter-exit matching is broken.
1920 //
1921 // Optionally release any monitors for regular JavaThread exits. This
1922 // is provided as a work around for any bugs in monitor enter-exit
1923 // matching. This can be expensive so it is not enabled by default.
1924 //
1925 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1926 // ObjectSynchronizer::release_monitors_owned_by_thread().
1927 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
1928 // Sanity check even though JNI DetachCurrentThread() would have
1929 // returned JNI_ERR if there was a Java frame. JavaThread exit
1930 // should be done executing Java code by the time we get here.
1931 assert(!this->has_last_Java_frame(),
1932 "should not have a Java frame when detaching or exiting");
1933 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1934 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1935 }
1936
1937 // These things needs to be done while we are still a Java Thread. Make sure that thread
1938 // is in a consistent state, in case GC happens
1939 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1940
1941 if (active_handles() != NULL) {
1942 JNIHandleBlock* block = active_handles();
1943 set_active_handles(NULL);
1944 JNIHandleBlock::release_block(block);
1945 }
1946
1947 if (free_handle_block() != NULL) {
1948 JNIHandleBlock* block = free_handle_block();
1949 set_free_handle_block(NULL);
1950 JNIHandleBlock::release_block(block);
1951 }
1952
1953 // These have to be removed while this is still a valid thread.
1954 remove_stack_guard_pages();
1955
1956 if (UseTLAB) {
1957 tlab().make_parsable(true); // retire TLAB
1958 }
1959
1960 if (JvmtiEnv::environments_might_exist()) {
1961 JvmtiExport::cleanup_thread(this);
1962 }
1963
1964 // We must flush any deferred card marks and other various GC barrier
1965 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
1966 // before removing a thread from the list of active threads.
1967 BarrierSet::barrier_set()->on_thread_detach(this);
1968
1969 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
1970 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
1971 os::current_thread_id());
1972
1973 if (log_is_enabled(Debug, os, thread, timer)) {
1974 _timer_exit_phase3.stop();
1975 _timer_exit_phase4.start();
1976 }
1977 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1978 Threads::remove(this);
1979
1980 if (log_is_enabled(Debug, os, thread, timer)) {
1981 _timer_exit_phase4.stop();
1982 ResourceMark rm(this);
1983 log_debug(os, thread, timer)("name='%s'"
1984 ", exit-phase1=" JLONG_FORMAT
1985 ", exit-phase2=" JLONG_FORMAT
1986 ", exit-phase3=" JLONG_FORMAT
1987 ", exit-phase4=" JLONG_FORMAT,
1988 get_thread_name(),
1989 _timer_exit_phase1.milliseconds(),
1990 _timer_exit_phase2.milliseconds(),
1991 _timer_exit_phase3.milliseconds(),
1992 _timer_exit_phase4.milliseconds());
1993 }
1994 }
1995
1996 void JavaThread::cleanup_failed_attach_current_thread() {
1997 if (active_handles() != NULL) {
1998 JNIHandleBlock* block = active_handles();
1999 set_active_handles(NULL);
2000 JNIHandleBlock::release_block(block);
2001 }
2002
2003 if (free_handle_block() != NULL) {
2004 JNIHandleBlock* block = free_handle_block();
2005 set_free_handle_block(NULL);
2006 JNIHandleBlock::release_block(block);
2007 }
2008
2009 // These have to be removed while this is still a valid thread.
2010 remove_stack_guard_pages();
2011
2012 if (UseTLAB) {
2013 tlab().make_parsable(true); // retire TLAB, if any
2014 }
2015
2016 BarrierSet::barrier_set()->on_thread_detach(this);
2017
2018 Threads::remove(this);
2019 this->smr_delete();
2020 }
2021
2022 JavaThread* JavaThread::active() {
2023 Thread* thread = Thread::current();
2024 if (thread->is_Java_thread()) {
2025 return (JavaThread*) thread;
2026 } else {
2027 assert(thread->is_VM_thread(), "this must be a vm thread");
2028 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2029 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2030 assert(ret->is_Java_thread(), "must be a Java thread");
2031 return ret;
2032 }
2033 }
2034
2035 bool JavaThread::is_lock_owned(address adr) const {
2036 if (Thread::is_lock_owned(adr)) return true;
2037
2038 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2039 if (chunk->contains(adr)) return true;
2040 }
2041
2042 return false;
2043 }
2044
2045
2046 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2047 chunk->set_next(monitor_chunks());
2048 set_monitor_chunks(chunk);
2049 }
2050
2051 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2052 guarantee(monitor_chunks() != NULL, "must be non empty");
2053 if (monitor_chunks() == chunk) {
2054 set_monitor_chunks(chunk->next());
2055 } else {
2056 MonitorChunk* prev = monitor_chunks();
2057 while (prev->next() != chunk) prev = prev->next();
2058 prev->set_next(chunk->next());
2059 }
2060 }
2061
2062 // JVM support.
2063
2064 // Note: this function shouldn't block if it's called in
2065 // _thread_in_native_trans state (such as from
2066 // check_special_condition_for_native_trans()).
2067 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2068
2069 if (has_last_Java_frame() && has_async_condition()) {
2070 // If we are at a polling page safepoint (not a poll return)
2071 // then we must defer async exception because live registers
2072 // will be clobbered by the exception path. Poll return is
2073 // ok because the call we a returning from already collides
2074 // with exception handling registers and so there is no issue.
2075 // (The exception handling path kills call result registers but
2076 // this is ok since the exception kills the result anyway).
2077
2078 if (is_at_poll_safepoint()) {
2079 // if the code we are returning to has deoptimized we must defer
2080 // the exception otherwise live registers get clobbered on the
2081 // exception path before deoptimization is able to retrieve them.
2082 //
2083 RegisterMap map(this, false);
2084 frame caller_fr = last_frame().sender(&map);
2085 assert(caller_fr.is_compiled_frame(), "what?");
2086 if (caller_fr.is_deoptimized_frame()) {
2087 log_info(exceptions)("deferred async exception at compiled safepoint");
2088 return;
2089 }
2090 }
2091 }
2092
2093 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2094 if (condition == _no_async_condition) {
2095 // Conditions have changed since has_special_runtime_exit_condition()
2096 // was called:
2097 // - if we were here only because of an external suspend request,
2098 // then that was taken care of above (or cancelled) so we are done
2099 // - if we were here because of another async request, then it has
2100 // been cleared between the has_special_runtime_exit_condition()
2101 // and now so again we are done
2102 return;
2103 }
2104
2105 // Check for pending async. exception
2106 if (_pending_async_exception != NULL) {
2107 // Only overwrite an already pending exception, if it is not a threadDeath.
2108 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2109
2110 // We cannot call Exceptions::_throw(...) here because we cannot block
2111 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2112
2113 LogTarget(Info, exceptions) lt;
2114 if (lt.is_enabled()) {
2115 ResourceMark rm;
2116 LogStream ls(lt);
2117 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2118 if (has_last_Java_frame()) {
2119 frame f = last_frame();
2120 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2121 }
2122 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2123 }
2124 _pending_async_exception = NULL;
2125 clear_has_async_exception();
2126 }
2127 }
2128
2129 if (check_unsafe_error &&
2130 condition == _async_unsafe_access_error && !has_pending_exception()) {
2131 condition = _no_async_condition; // done
2132 switch (thread_state()) {
2133 case _thread_in_vm: {
2134 JavaThread* THREAD = this;
2135 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2136 }
2137 case _thread_in_native: {
2138 ThreadInVMfromNative tiv(this);
2139 JavaThread* THREAD = this;
2140 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2141 }
2142 case _thread_in_Java: {
2143 ThreadInVMfromJava tiv(this);
2144 JavaThread* THREAD = this;
2145 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2146 }
2147 default:
2148 ShouldNotReachHere();
2149 }
2150 }
2151
2152 assert(condition == _no_async_condition || has_pending_exception() ||
2153 (!check_unsafe_error && condition == _async_unsafe_access_error),
2154 "must have handled the async condition, if no exception");
2155 }
2156
2157 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2158 //
2159 // Check for pending external suspend. Internal suspend requests do
2160 // not use handle_special_runtime_exit_condition().
2161 // If JNIEnv proxies are allowed, don't self-suspend if the target
2162 // thread is not the current thread. In older versions of jdbx, jdbx
2163 // threads could call into the VM with another thread's JNIEnv so we
2164 // can be here operating on behalf of a suspended thread (4432884).
2165 bool do_self_suspend = is_external_suspend_with_lock();
2166 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2167 //
2168 // Because thread is external suspended the safepoint code will count
2169 // thread as at a safepoint. This can be odd because we can be here
2170 // as _thread_in_Java which would normally transition to _thread_blocked
2171 // at a safepoint. We would like to mark the thread as _thread_blocked
2172 // before calling java_suspend_self like all other callers of it but
2173 // we must then observe proper safepoint protocol. (We can't leave
2174 // _thread_blocked with a safepoint in progress). However we can be
2175 // here as _thread_in_native_trans so we can't use a normal transition
2176 // constructor/destructor pair because they assert on that type of
2177 // transition. We could do something like:
2178 //
2179 // JavaThreadState state = thread_state();
2180 // set_thread_state(_thread_in_vm);
2181 // {
2182 // ThreadBlockInVM tbivm(this);
2183 // java_suspend_self()
2184 // }
2185 // set_thread_state(_thread_in_vm_trans);
2186 // if (safepoint) block;
2187 // set_thread_state(state);
2188 //
2189 // but that is pretty messy. Instead we just go with the way the
2190 // code has worked before and note that this is the only path to
2191 // java_suspend_self that doesn't put the thread in _thread_blocked
2192 // mode.
2193
2194 frame_anchor()->make_walkable(this);
2195 java_suspend_self();
2196
2197 // We might be here for reasons in addition to the self-suspend request
2198 // so check for other async requests.
2199 }
2200
2201 if (check_asyncs) {
2202 check_and_handle_async_exceptions();
2203 }
2204
2205 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2206 }
2207
2208 void JavaThread::send_thread_stop(oop java_throwable) {
2209 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2210 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2211 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2212
2213 // Do not throw asynchronous exceptions against the compiler thread
2214 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2215 if (!can_call_java()) return;
2216
2217 {
2218 // Actually throw the Throwable against the target Thread - however
2219 // only if there is no thread death exception installed already.
2220 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2221 // If the topmost frame is a runtime stub, then we are calling into
2222 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2223 // must deoptimize the caller before continuing, as the compiled exception handler table
2224 // may not be valid
2225 if (has_last_Java_frame()) {
2226 frame f = last_frame();
2227 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2228 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2229 RegisterMap reg_map(this, UseBiasedLocking);
2230 frame compiled_frame = f.sender(®_map);
2231 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2232 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2233 }
2234 }
2235 }
2236
2237 // Set async. pending exception in thread.
2238 set_pending_async_exception(java_throwable);
2239
2240 if (log_is_enabled(Info, exceptions)) {
2241 ResourceMark rm;
2242 log_info(exceptions)("Pending Async. exception installed of type: %s",
2243 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2244 }
2245 // for AbortVMOnException flag
2246 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2247 }
2248 }
2249
2250
2251 // Interrupt thread so it will wake up from a potential wait()
2252 Thread::interrupt(this);
2253 }
2254
2255 // External suspension mechanism.
2256 //
2257 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2258 // to any VM_locks and it is at a transition
2259 // Self-suspension will happen on the transition out of the vm.
2260 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2261 //
2262 // Guarantees on return:
2263 // + Target thread will not execute any new bytecode (that's why we need to
2264 // force a safepoint)
2265 // + Target thread will not enter any new monitors
2266 //
2267 void JavaThread::java_suspend() {
2268 ThreadsListHandle tlh;
2269 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2270 return;
2271 }
2272
2273 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2274 if (!is_external_suspend()) {
2275 // a racing resume has cancelled us; bail out now
2276 return;
2277 }
2278
2279 // suspend is done
2280 uint32_t debug_bits = 0;
2281 // Warning: is_ext_suspend_completed() may temporarily drop the
2282 // SR_lock to allow the thread to reach a stable thread state if
2283 // it is currently in a transient thread state.
2284 if (is_ext_suspend_completed(false /* !called_by_wait */,
2285 SuspendRetryDelay, &debug_bits)) {
2286 return;
2287 }
2288 }
2289
2290 VM_ThreadSuspend vm_suspend;
2291 VMThread::execute(&vm_suspend);
2292 }
2293
2294 // Part II of external suspension.
2295 // A JavaThread self suspends when it detects a pending external suspend
2296 // request. This is usually on transitions. It is also done in places
2297 // where continuing to the next transition would surprise the caller,
2298 // e.g., monitor entry.
2299 //
2300 // Returns the number of times that the thread self-suspended.
2301 //
2302 // Note: DO NOT call java_suspend_self() when you just want to block current
2303 // thread. java_suspend_self() is the second stage of cooperative
2304 // suspension for external suspend requests and should only be used
2305 // to complete an external suspend request.
2306 //
2307 int JavaThread::java_suspend_self() {
2308 int ret = 0;
2309
2310 // we are in the process of exiting so don't suspend
2311 if (is_exiting()) {
2312 clear_external_suspend();
2313 return ret;
2314 }
2315
2316 assert(_anchor.walkable() ||
2317 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2318 "must have walkable stack");
2319
2320 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2321
2322 assert(!this->is_ext_suspended(),
2323 "a thread trying to self-suspend should not already be suspended");
2324
2325 if (this->is_suspend_equivalent()) {
2326 // If we are self-suspending as a result of the lifting of a
2327 // suspend equivalent condition, then the suspend_equivalent
2328 // flag is not cleared until we set the ext_suspended flag so
2329 // that wait_for_ext_suspend_completion() returns consistent
2330 // results.
2331 this->clear_suspend_equivalent();
2332 }
2333
2334 // A racing resume may have cancelled us before we grabbed SR_lock
2335 // above. Or another external suspend request could be waiting for us
2336 // by the time we return from SR_lock()->wait(). The thread
2337 // that requested the suspension may already be trying to walk our
2338 // stack and if we return now, we can change the stack out from under
2339 // it. This would be a "bad thing (TM)" and cause the stack walker
2340 // to crash. We stay self-suspended until there are no more pending
2341 // external suspend requests.
2342 while (is_external_suspend()) {
2343 ret++;
2344 this->set_ext_suspended();
2345
2346 // _ext_suspended flag is cleared by java_resume()
2347 while (is_ext_suspended()) {
2348 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2349 }
2350 }
2351
2352 return ret;
2353 }
2354
2355 #ifdef ASSERT
2356 // Verify the JavaThread has not yet been published in the Threads::list, and
2357 // hence doesn't need protection from concurrent access at this stage.
2358 void JavaThread::verify_not_published() {
2359 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2360 // since an unpublished JavaThread doesn't participate in the
2361 // Thread-SMR protocol for keeping a ThreadsList alive.
2362 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2363 }
2364 #endif
2365
2366 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2367 // progress or when _suspend_flags is non-zero.
2368 // Current thread needs to self-suspend if there is a suspend request and/or
2369 // block if a safepoint is in progress.
2370 // Async exception ISN'T checked.
2371 // Note only the ThreadInVMfromNative transition can call this function
2372 // directly and when thread state is _thread_in_native_trans
2373 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2374 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2375
2376 JavaThread *curJT = JavaThread::current();
2377 bool do_self_suspend = thread->is_external_suspend();
2378
2379 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2380
2381 // If JNIEnv proxies are allowed, don't self-suspend if the target
2382 // thread is not the current thread. In older versions of jdbx, jdbx
2383 // threads could call into the VM with another thread's JNIEnv so we
2384 // can be here operating on behalf of a suspended thread (4432884).
2385 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2386 JavaThreadState state = thread->thread_state();
2387
2388 // We mark this thread_blocked state as a suspend-equivalent so
2389 // that a caller to is_ext_suspend_completed() won't be confused.
2390 // The suspend-equivalent state is cleared by java_suspend_self().
2391 thread->set_suspend_equivalent();
2392
2393 // If the safepoint code sees the _thread_in_native_trans state, it will
2394 // wait until the thread changes to other thread state. There is no
2395 // guarantee on how soon we can obtain the SR_lock and complete the
2396 // self-suspend request. It would be a bad idea to let safepoint wait for
2397 // too long. Temporarily change the state to _thread_blocked to
2398 // let the VM thread know that this thread is ready for GC. The problem
2399 // of changing thread state is that safepoint could happen just after
2400 // java_suspend_self() returns after being resumed, and VM thread will
2401 // see the _thread_blocked state. We must check for safepoint
2402 // after restoring the state and make sure we won't leave while a safepoint
2403 // is in progress.
2404 thread->set_thread_state(_thread_blocked);
2405 thread->java_suspend_self();
2406 thread->set_thread_state(state);
2407
2408 InterfaceSupport::serialize_thread_state_with_handler(thread);
2409 }
2410
2411 SafepointMechanism::block_if_requested(curJT);
2412
2413 if (thread->is_deopt_suspend()) {
2414 thread->clear_deopt_suspend();
2415 RegisterMap map(thread, false);
2416 frame f = thread->last_frame();
2417 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2418 f = f.sender(&map);
2419 }
2420 if (f.id() == thread->must_deopt_id()) {
2421 thread->clear_must_deopt_id();
2422 f.deoptimize(thread);
2423 } else {
2424 fatal("missed deoptimization!");
2425 }
2426 }
2427
2428 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2429 }
2430
2431 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2432 // progress or when _suspend_flags is non-zero.
2433 // Current thread needs to self-suspend if there is a suspend request and/or
2434 // block if a safepoint is in progress.
2435 // Also check for pending async exception (not including unsafe access error).
2436 // Note only the native==>VM/Java barriers can call this function and when
2437 // thread state is _thread_in_native_trans.
2438 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2439 check_safepoint_and_suspend_for_native_trans(thread);
2440
2441 if (thread->has_async_exception()) {
2442 // We are in _thread_in_native_trans state, don't handle unsafe
2443 // access error since that may block.
2444 thread->check_and_handle_async_exceptions(false);
2445 }
2446 }
2447
2448 // This is a variant of the normal
2449 // check_special_condition_for_native_trans with slightly different
2450 // semantics for use by critical native wrappers. It does all the
2451 // normal checks but also performs the transition back into
2452 // thread_in_Java state. This is required so that critical natives
2453 // can potentially block and perform a GC if they are the last thread
2454 // exiting the GCLocker.
2455 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2456 check_special_condition_for_native_trans(thread);
2457
2458 // Finish the transition
2459 thread->set_thread_state(_thread_in_Java);
2460
2461 if (thread->do_critical_native_unlock()) {
2462 ThreadInVMfromJavaNoAsyncException tiv(thread);
2463 GCLocker::unlock_critical(thread);
2464 thread->clear_critical_native_unlock();
2465 }
2466 }
2467
2468 // We need to guarantee the Threads_lock here, since resumes are not
2469 // allowed during safepoint synchronization
2470 // Can only resume from an external suspension
2471 void JavaThread::java_resume() {
2472 assert_locked_or_safepoint(Threads_lock);
2473
2474 // Sanity check: thread is gone, has started exiting or the thread
2475 // was not externally suspended.
2476 ThreadsListHandle tlh;
2477 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2478 return;
2479 }
2480
2481 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2482
2483 clear_external_suspend();
2484
2485 if (is_ext_suspended()) {
2486 clear_ext_suspended();
2487 SR_lock()->notify_all();
2488 }
2489 }
2490
2491 size_t JavaThread::_stack_red_zone_size = 0;
2492 size_t JavaThread::_stack_yellow_zone_size = 0;
2493 size_t JavaThread::_stack_reserved_zone_size = 0;
2494 size_t JavaThread::_stack_shadow_zone_size = 0;
2495
2496 void JavaThread::create_stack_guard_pages() {
2497 if (!os::uses_stack_guard_pages() ||
2498 _stack_guard_state != stack_guard_unused ||
2499 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2500 log_info(os, thread)("Stack guard page creation for thread "
2501 UINTX_FORMAT " disabled", os::current_thread_id());
2502 return;
2503 }
2504 address low_addr = stack_end();
2505 size_t len = stack_guard_zone_size();
2506
2507 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2508 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2509
2510 int must_commit = os::must_commit_stack_guard_pages();
2511 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2512
2513 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2514 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2515 return;
2516 }
2517
2518 if (os::guard_memory((char *) low_addr, len)) {
2519 _stack_guard_state = stack_guard_enabled;
2520 } else {
2521 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2522 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2523 if (os::uncommit_memory((char *) low_addr, len)) {
2524 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2525 }
2526 return;
2527 }
2528
2529 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2530 PTR_FORMAT "-" PTR_FORMAT ".",
2531 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2532 }
2533
2534 void JavaThread::remove_stack_guard_pages() {
2535 assert(Thread::current() == this, "from different thread");
2536 if (_stack_guard_state == stack_guard_unused) return;
2537 address low_addr = stack_end();
2538 size_t len = stack_guard_zone_size();
2539
2540 if (os::must_commit_stack_guard_pages()) {
2541 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2542 _stack_guard_state = stack_guard_unused;
2543 } else {
2544 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2545 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2546 return;
2547 }
2548 } else {
2549 if (_stack_guard_state == stack_guard_unused) return;
2550 if (os::unguard_memory((char *) low_addr, len)) {
2551 _stack_guard_state = stack_guard_unused;
2552 } else {
2553 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2554 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2555 return;
2556 }
2557 }
2558
2559 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2560 PTR_FORMAT "-" PTR_FORMAT ".",
2561 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2562 }
2563
2564 void JavaThread::enable_stack_reserved_zone() {
2565 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2566 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2567
2568 // The base notation is from the stack's point of view, growing downward.
2569 // We need to adjust it to work correctly with guard_memory()
2570 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2571
2572 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2573 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2574
2575 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2576 _stack_guard_state = stack_guard_enabled;
2577 } else {
2578 warning("Attempt to guard stack reserved zone failed.");
2579 }
2580 enable_register_stack_guard();
2581 }
2582
2583 void JavaThread::disable_stack_reserved_zone() {
2584 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2585 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled");
2586
2587 // Simply return if called for a thread that does not use guard pages.
2588 if (_stack_guard_state == stack_guard_unused) return;
2589
2590 // The base notation is from the stack's point of view, growing downward.
2591 // We need to adjust it to work correctly with guard_memory()
2592 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2593
2594 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2595 _stack_guard_state = stack_guard_reserved_disabled;
2596 } else {
2597 warning("Attempt to unguard stack reserved zone failed.");
2598 }
2599 disable_register_stack_guard();
2600 }
2601
2602 void JavaThread::enable_stack_yellow_reserved_zone() {
2603 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2604 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2605
2606 // The base notation is from the stacks point of view, growing downward.
2607 // We need to adjust it to work correctly with guard_memory()
2608 address base = stack_red_zone_base();
2609
2610 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2611 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2612
2613 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2614 _stack_guard_state = stack_guard_enabled;
2615 } else {
2616 warning("Attempt to guard stack yellow zone failed.");
2617 }
2618 enable_register_stack_guard();
2619 }
2620
2621 void JavaThread::disable_stack_yellow_reserved_zone() {
2622 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2623 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2624
2625 // Simply return if called for a thread that does not use guard pages.
2626 if (_stack_guard_state == stack_guard_unused) return;
2627
2628 // The base notation is from the stacks point of view, growing downward.
2629 // We need to adjust it to work correctly with guard_memory()
2630 address base = stack_red_zone_base();
2631
2632 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2633 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2634 } else {
2635 warning("Attempt to unguard stack yellow zone failed.");
2636 }
2637 disable_register_stack_guard();
2638 }
2639
2640 void JavaThread::enable_stack_red_zone() {
2641 // The base notation is from the stacks point of view, growing downward.
2642 // We need to adjust it to work correctly with guard_memory()
2643 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2644 address base = stack_red_zone_base() - stack_red_zone_size();
2645
2646 guarantee(base < stack_base(), "Error calculating stack red zone");
2647 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2648
2649 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2650 warning("Attempt to guard stack red zone failed.");
2651 }
2652 }
2653
2654 void JavaThread::disable_stack_red_zone() {
2655 // The base notation is from the stacks point of view, growing downward.
2656 // We need to adjust it to work correctly with guard_memory()
2657 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2658 address base = stack_red_zone_base() - stack_red_zone_size();
2659 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2660 warning("Attempt to unguard stack red zone failed.");
2661 }
2662 }
2663
2664 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2665 // ignore is there is no stack
2666 if (!has_last_Java_frame()) return;
2667 // traverse the stack frames. Starts from top frame.
2668 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2669 frame* fr = fst.current();
2670 f(fr, fst.register_map());
2671 }
2672 }
2673
2674
2675 #ifndef PRODUCT
2676 // Deoptimization
2677 // Function for testing deoptimization
2678 void JavaThread::deoptimize() {
2679 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2680 StackFrameStream fst(this, UseBiasedLocking);
2681 bool deopt = false; // Dump stack only if a deopt actually happens.
2682 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2683 // Iterate over all frames in the thread and deoptimize
2684 for (; !fst.is_done(); fst.next()) {
2685 if (fst.current()->can_be_deoptimized()) {
2686
2687 if (only_at) {
2688 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2689 // consists of comma or carriage return separated numbers so
2690 // search for the current bci in that string.
2691 address pc = fst.current()->pc();
2692 nmethod* nm = (nmethod*) fst.current()->cb();
2693 ScopeDesc* sd = nm->scope_desc_at(pc);
2694 char buffer[8];
2695 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2696 size_t len = strlen(buffer);
2697 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2698 while (found != NULL) {
2699 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2700 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2701 // Check that the bci found is bracketed by terminators.
2702 break;
2703 }
2704 found = strstr(found + 1, buffer);
2705 }
2706 if (!found) {
2707 continue;
2708 }
2709 }
2710
2711 if (DebugDeoptimization && !deopt) {
2712 deopt = true; // One-time only print before deopt
2713 tty->print_cr("[BEFORE Deoptimization]");
2714 trace_frames();
2715 trace_stack();
2716 }
2717 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2718 }
2719 }
2720
2721 if (DebugDeoptimization && deopt) {
2722 tty->print_cr("[AFTER Deoptimization]");
2723 trace_frames();
2724 }
2725 }
2726
2727
2728 // Make zombies
2729 void JavaThread::make_zombies() {
2730 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2731 if (fst.current()->can_be_deoptimized()) {
2732 // it is a Java nmethod
2733 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2734 nm->make_not_entrant();
2735 }
2736 }
2737 }
2738 #endif // PRODUCT
2739
2740
2741 void JavaThread::deoptimized_wrt_marked_nmethods() {
2742 if (!has_last_Java_frame()) return;
2743 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2744 StackFrameStream fst(this, UseBiasedLocking);
2745 for (; !fst.is_done(); fst.next()) {
2746 if (fst.current()->should_be_deoptimized()) {
2747 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2748 }
2749 }
2750 }
2751
2752
2753 // If the caller is a NamedThread, then remember, in the current scope,
2754 // the given JavaThread in its _processed_thread field.
2755 class RememberProcessedThread: public StackObj {
2756 NamedThread* _cur_thr;
2757 public:
2758 RememberProcessedThread(JavaThread* jthr) {
2759 Thread* thread = Thread::current();
2760 if (thread->is_Named_thread()) {
2761 _cur_thr = (NamedThread *)thread;
2762 _cur_thr->set_processed_thread(jthr);
2763 } else {
2764 _cur_thr = NULL;
2765 }
2766 }
2767
2768 ~RememberProcessedThread() {
2769 if (_cur_thr) {
2770 _cur_thr->set_processed_thread(NULL);
2771 }
2772 }
2773 };
2774
2775 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2776 // Verify that the deferred card marks have been flushed.
2777 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2778
2779 // Traverse the GCHandles
2780 Thread::oops_do(f, cf);
2781
2782 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2783
2784 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2785 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2786
2787 if (has_last_Java_frame()) {
2788 // Record JavaThread to GC thread
2789 RememberProcessedThread rpt(this);
2790
2791 // Traverse the privileged stack
2792 if (_privileged_stack_top != NULL) {
2793 _privileged_stack_top->oops_do(f);
2794 }
2795
2796 // traverse the registered growable array
2797 if (_array_for_gc != NULL) {
2798 for (int index = 0; index < _array_for_gc->length(); index++) {
2799 f->do_oop(_array_for_gc->adr_at(index));
2800 }
2801 }
2802
2803 // Traverse the monitor chunks
2804 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2805 chunk->oops_do(f);
2806 }
2807
2808 // Traverse the execution stack
2809 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2810 fst.current()->oops_do(f, cf, fst.register_map());
2811 }
2812 }
2813
2814 // callee_target is never live across a gc point so NULL it here should
2815 // it still contain a methdOop.
2816
2817 set_callee_target(NULL);
2818
2819 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2820 // If we have deferred set_locals there might be oops waiting to be
2821 // written
2822 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2823 if (list != NULL) {
2824 for (int i = 0; i < list->length(); i++) {
2825 list->at(i)->oops_do(f);
2826 }
2827 }
2828
2829 // Traverse instance variables at the end since the GC may be moving things
2830 // around using this function
2831 f->do_oop((oop*) &_threadObj);
2832 f->do_oop((oop*) &_vm_result);
2833 f->do_oop((oop*) &_exception_oop);
2834 f->do_oop((oop*) &_pending_async_exception);
2835
2836 if (jvmti_thread_state() != NULL) {
2837 jvmti_thread_state()->oops_do(f);
2838 }
2839 }
2840
2841 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2842 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2843 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2844
2845 if (has_last_Java_frame()) {
2846 // Traverse the execution stack
2847 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2848 fst.current()->nmethods_do(cf);
2849 }
2850 }
2851 }
2852
2853 void JavaThread::metadata_do(void f(Metadata*)) {
2854 if (has_last_Java_frame()) {
2855 // Traverse the execution stack to call f() on the methods in the stack
2856 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2857 fst.current()->metadata_do(f);
2858 }
2859 } else if (is_Compiler_thread()) {
2860 // need to walk ciMetadata in current compile tasks to keep alive.
2861 CompilerThread* ct = (CompilerThread*)this;
2862 if (ct->env() != NULL) {
2863 ct->env()->metadata_do(f);
2864 }
2865 CompileTask* task = ct->task();
2866 if (task != NULL) {
2867 task->metadata_do(f);
2868 }
2869 }
2870 }
2871
2872 // Printing
2873 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2874 switch (_thread_state) {
2875 case _thread_uninitialized: return "_thread_uninitialized";
2876 case _thread_new: return "_thread_new";
2877 case _thread_new_trans: return "_thread_new_trans";
2878 case _thread_in_native: return "_thread_in_native";
2879 case _thread_in_native_trans: return "_thread_in_native_trans";
2880 case _thread_in_vm: return "_thread_in_vm";
2881 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2882 case _thread_in_Java: return "_thread_in_Java";
2883 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2884 case _thread_blocked: return "_thread_blocked";
2885 case _thread_blocked_trans: return "_thread_blocked_trans";
2886 default: return "unknown thread state";
2887 }
2888 }
2889
2890 #ifndef PRODUCT
2891 void JavaThread::print_thread_state_on(outputStream *st) const {
2892 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2893 };
2894 void JavaThread::print_thread_state() const {
2895 print_thread_state_on(tty);
2896 }
2897 #endif // PRODUCT
2898
2899 // Called by Threads::print() for VM_PrintThreads operation
2900 void JavaThread::print_on(outputStream *st) const {
2901 st->print_raw("\"");
2902 st->print_raw(get_thread_name());
2903 st->print_raw("\" ");
2904 oop thread_oop = threadObj();
2905 if (thread_oop != NULL) {
2906 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
2907 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2908 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2909 }
2910 Thread::print_on(st);
2911 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2912 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2913 if (thread_oop != NULL) {
2914 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2915 }
2916 #ifndef PRODUCT
2917 print_thread_state_on(st);
2918 _safepoint_state->print_on(st);
2919 #endif // PRODUCT
2920 if (is_Compiler_thread()) {
2921 CompileTask *task = ((CompilerThread*)this)->task();
2922 if (task != NULL) {
2923 st->print(" Compiling: ");
2924 task->print(st, NULL, true, false);
2925 } else {
2926 st->print(" No compile task");
2927 }
2928 st->cr();
2929 }
2930 }
2931
2932 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
2933 st->print("%s", get_thread_name_string(buf, buflen));
2934 }
2935
2936 // Called by fatal error handler. The difference between this and
2937 // JavaThread::print() is that we can't grab lock or allocate memory.
2938 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2939 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2940 oop thread_obj = threadObj();
2941 if (thread_obj != NULL) {
2942 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2943 }
2944 st->print(" [");
2945 st->print("%s", _get_thread_state_name(_thread_state));
2946 if (osthread()) {
2947 st->print(", id=%d", osthread()->thread_id());
2948 }
2949 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2950 p2i(stack_end()), p2i(stack_base()));
2951 st->print("]");
2952
2953 ThreadsSMRSupport::print_info_on(this, st);
2954 return;
2955 }
2956
2957 // Verification
2958
2959 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2960
2961 void JavaThread::verify() {
2962 // Verify oops in the thread.
2963 oops_do(&VerifyOopClosure::verify_oop, NULL);
2964
2965 // Verify the stack frames.
2966 frames_do(frame_verify);
2967 }
2968
2969 // CR 6300358 (sub-CR 2137150)
2970 // Most callers of this method assume that it can't return NULL but a
2971 // thread may not have a name whilst it is in the process of attaching to
2972 // the VM - see CR 6412693, and there are places where a JavaThread can be
2973 // seen prior to having it's threadObj set (eg JNI attaching threads and
2974 // if vm exit occurs during initialization). These cases can all be accounted
2975 // for such that this method never returns NULL.
2976 const char* JavaThread::get_thread_name() const {
2977 #ifdef ASSERT
2978 // early safepoints can hit while current thread does not yet have TLS
2979 if (!SafepointSynchronize::is_at_safepoint()) {
2980 Thread *cur = Thread::current();
2981 if (!(cur->is_Java_thread() && cur == this)) {
2982 // Current JavaThreads are allowed to get their own name without
2983 // the Threads_lock.
2984 assert_locked_or_safepoint(Threads_lock);
2985 }
2986 }
2987 #endif // ASSERT
2988 return get_thread_name_string();
2989 }
2990
2991 // Returns a non-NULL representation of this thread's name, or a suitable
2992 // descriptive string if there is no set name
2993 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2994 const char* name_str;
2995 oop thread_obj = threadObj();
2996 if (thread_obj != NULL) {
2997 oop name = java_lang_Thread::name(thread_obj);
2998 if (name != NULL) {
2999 if (buf == NULL) {
3000 name_str = java_lang_String::as_utf8_string(name);
3001 } else {
3002 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3003 }
3004 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3005 name_str = "<no-name - thread is attaching>";
3006 } else {
3007 name_str = Thread::name();
3008 }
3009 } else {
3010 name_str = Thread::name();
3011 }
3012 assert(name_str != NULL, "unexpected NULL thread name");
3013 return name_str;
3014 }
3015
3016
3017 const char* JavaThread::get_threadgroup_name() const {
3018 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3019 oop thread_obj = threadObj();
3020 if (thread_obj != NULL) {
3021 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3022 if (thread_group != NULL) {
3023 // ThreadGroup.name can be null
3024 return java_lang_ThreadGroup::name(thread_group);
3025 }
3026 }
3027 return NULL;
3028 }
3029
3030 const char* JavaThread::get_parent_name() const {
3031 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3032 oop thread_obj = threadObj();
3033 if (thread_obj != NULL) {
3034 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3035 if (thread_group != NULL) {
3036 oop parent = java_lang_ThreadGroup::parent(thread_group);
3037 if (parent != NULL) {
3038 // ThreadGroup.name can be null
3039 return java_lang_ThreadGroup::name(parent);
3040 }
3041 }
3042 }
3043 return NULL;
3044 }
3045
3046 ThreadPriority JavaThread::java_priority() const {
3047 oop thr_oop = threadObj();
3048 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3049 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3050 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3051 return priority;
3052 }
3053
3054 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3055
3056 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3057 // Link Java Thread object <-> C++ Thread
3058
3059 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3060 // and put it into a new Handle. The Handle "thread_oop" can then
3061 // be used to pass the C++ thread object to other methods.
3062
3063 // Set the Java level thread object (jthread) field of the
3064 // new thread (a JavaThread *) to C++ thread object using the
3065 // "thread_oop" handle.
3066
3067 // Set the thread field (a JavaThread *) of the
3068 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3069
3070 Handle thread_oop(Thread::current(),
3071 JNIHandles::resolve_non_null(jni_thread));
3072 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3073 "must be initialized");
3074 set_threadObj(thread_oop());
3075 java_lang_Thread::set_thread(thread_oop(), this);
3076
3077 if (prio == NoPriority) {
3078 prio = java_lang_Thread::priority(thread_oop());
3079 assert(prio != NoPriority, "A valid priority should be present");
3080 }
3081
3082 // Push the Java priority down to the native thread; needs Threads_lock
3083 Thread::set_priority(this, prio);
3084
3085 // Add the new thread to the Threads list and set it in motion.
3086 // We must have threads lock in order to call Threads::add.
3087 // It is crucial that we do not block before the thread is
3088 // added to the Threads list for if a GC happens, then the java_thread oop
3089 // will not be visited by GC.
3090 Threads::add(this);
3091 }
3092
3093 oop JavaThread::current_park_blocker() {
3094 // Support for JSR-166 locks
3095 oop thread_oop = threadObj();
3096 if (thread_oop != NULL &&
3097 JDK_Version::current().supports_thread_park_blocker()) {
3098 return java_lang_Thread::park_blocker(thread_oop);
3099 }
3100 return NULL;
3101 }
3102
3103
3104 void JavaThread::print_stack_on(outputStream* st) {
3105 if (!has_last_Java_frame()) return;
3106 ResourceMark rm;
3107 HandleMark hm;
3108
3109 RegisterMap reg_map(this);
3110 vframe* start_vf = last_java_vframe(®_map);
3111 int count = 0;
3112 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3113 if (f->is_java_frame()) {
3114 javaVFrame* jvf = javaVFrame::cast(f);
3115 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3116
3117 // Print out lock information
3118 if (JavaMonitorsInStackTrace) {
3119 jvf->print_lock_info_on(st, count);
3120 }
3121 } else {
3122 // Ignore non-Java frames
3123 }
3124
3125 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3126 count++;
3127 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3128 }
3129 }
3130
3131
3132 // JVMTI PopFrame support
3133 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3134 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3135 if (in_bytes(size_in_bytes) != 0) {
3136 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3137 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3138 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3139 }
3140 }
3141
3142 void* JavaThread::popframe_preserved_args() {
3143 return _popframe_preserved_args;
3144 }
3145
3146 ByteSize JavaThread::popframe_preserved_args_size() {
3147 return in_ByteSize(_popframe_preserved_args_size);
3148 }
3149
3150 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3151 int sz = in_bytes(popframe_preserved_args_size());
3152 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3153 return in_WordSize(sz / wordSize);
3154 }
3155
3156 void JavaThread::popframe_free_preserved_args() {
3157 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3158 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3159 _popframe_preserved_args = NULL;
3160 _popframe_preserved_args_size = 0;
3161 }
3162
3163 #ifndef PRODUCT
3164
3165 void JavaThread::trace_frames() {
3166 tty->print_cr("[Describe stack]");
3167 int frame_no = 1;
3168 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3169 tty->print(" %d. ", frame_no++);
3170 fst.current()->print_value_on(tty, this);
3171 tty->cr();
3172 }
3173 }
3174
3175 class PrintAndVerifyOopClosure: public OopClosure {
3176 protected:
3177 template <class T> inline void do_oop_work(T* p) {
3178 oop obj = RawAccess<>::oop_load(p);
3179 if (obj == NULL) return;
3180 tty->print(INTPTR_FORMAT ": ", p2i(p));
3181 if (oopDesc::is_oop_or_null(obj)) {
3182 if (obj->is_objArray()) {
3183 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3184 } else {
3185 obj->print();
3186 }
3187 } else {
3188 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3189 }
3190 tty->cr();
3191 }
3192 public:
3193 virtual void do_oop(oop* p) { do_oop_work(p); }
3194 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3195 };
3196
3197
3198 static void oops_print(frame* f, const RegisterMap *map) {
3199 PrintAndVerifyOopClosure print;
3200 f->print_value();
3201 f->oops_do(&print, NULL, (RegisterMap*)map);
3202 }
3203
3204 // Print our all the locations that contain oops and whether they are
3205 // valid or not. This useful when trying to find the oldest frame
3206 // where an oop has gone bad since the frame walk is from youngest to
3207 // oldest.
3208 void JavaThread::trace_oops() {
3209 tty->print_cr("[Trace oops]");
3210 frames_do(oops_print);
3211 }
3212
3213
3214 #ifdef ASSERT
3215 // Print or validate the layout of stack frames
3216 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3217 ResourceMark rm;
3218 PRESERVE_EXCEPTION_MARK;
3219 FrameValues values;
3220 int frame_no = 0;
3221 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3222 fst.current()->describe(values, ++frame_no);
3223 if (depth == frame_no) break;
3224 }
3225 if (validate_only) {
3226 values.validate();
3227 } else {
3228 tty->print_cr("[Describe stack layout]");
3229 values.print(this);
3230 }
3231 }
3232 #endif
3233
3234 void JavaThread::trace_stack_from(vframe* start_vf) {
3235 ResourceMark rm;
3236 int vframe_no = 1;
3237 for (vframe* f = start_vf; f; f = f->sender()) {
3238 if (f->is_java_frame()) {
3239 javaVFrame::cast(f)->print_activation(vframe_no++);
3240 } else {
3241 f->print();
3242 }
3243 if (vframe_no > StackPrintLimit) {
3244 tty->print_cr("...<more frames>...");
3245 return;
3246 }
3247 }
3248 }
3249
3250
3251 void JavaThread::trace_stack() {
3252 if (!has_last_Java_frame()) return;
3253 ResourceMark rm;
3254 HandleMark hm;
3255 RegisterMap reg_map(this);
3256 trace_stack_from(last_java_vframe(®_map));
3257 }
3258
3259
3260 #endif // PRODUCT
3261
3262
3263 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3264 assert(reg_map != NULL, "a map must be given");
3265 frame f = last_frame();
3266 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3267 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3268 }
3269 return NULL;
3270 }
3271
3272
3273 Klass* JavaThread::security_get_caller_class(int depth) {
3274 vframeStream vfst(this);
3275 vfst.security_get_caller_frame(depth);
3276 if (!vfst.at_end()) {
3277 return vfst.method()->method_holder();
3278 }
3279 return NULL;
3280 }
3281
3282 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3283 assert(thread->is_Compiler_thread(), "must be compiler thread");
3284 CompileBroker::compiler_thread_loop();
3285 }
3286
3287 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3288 NMethodSweeper::sweeper_loop();
3289 }
3290
3291 // Create a CompilerThread
3292 CompilerThread::CompilerThread(CompileQueue* queue,
3293 CompilerCounters* counters)
3294 : JavaThread(&compiler_thread_entry) {
3295 _env = NULL;
3296 _log = NULL;
3297 _task = NULL;
3298 _queue = queue;
3299 _counters = counters;
3300 _buffer_blob = NULL;
3301 _compiler = NULL;
3302
3303 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3304 resource_area()->bias_to(mtCompiler);
3305
3306 #ifndef PRODUCT
3307 _ideal_graph_printer = NULL;
3308 #endif
3309 }
3310
3311 CompilerThread::~CompilerThread() {
3312 // Delete objects which were allocated on heap.
3313 delete _counters;
3314 }
3315
3316 bool CompilerThread::can_call_java() const {
3317 return _compiler != NULL && _compiler->is_jvmci();
3318 }
3319
3320 // Create sweeper thread
3321 CodeCacheSweeperThread::CodeCacheSweeperThread()
3322 : JavaThread(&sweeper_thread_entry) {
3323 _scanned_compiled_method = NULL;
3324 }
3325
3326 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3327 JavaThread::oops_do(f, cf);
3328 if (_scanned_compiled_method != NULL && cf != NULL) {
3329 // Safepoints can occur when the sweeper is scanning an nmethod so
3330 // process it here to make sure it isn't unloaded in the middle of
3331 // a scan.
3332 cf->do_code_blob(_scanned_compiled_method);
3333 }
3334 }
3335
3336 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3337 JavaThread::nmethods_do(cf);
3338 if (_scanned_compiled_method != NULL && cf != NULL) {
3339 // Safepoints can occur when the sweeper is scanning an nmethod so
3340 // process it here to make sure it isn't unloaded in the middle of
3341 // a scan.
3342 cf->do_code_blob(_scanned_compiled_method);
3343 }
3344 }
3345
3346
3347 // ======= Threads ========
3348
3349 // The Threads class links together all active threads, and provides
3350 // operations over all threads. It is protected by the Threads_lock,
3351 // which is also used in other global contexts like safepointing.
3352 // ThreadsListHandles are used to safely perform operations on one
3353 // or more threads without the risk of the thread exiting during the
3354 // operation.
3355 //
3356 // Note: The Threads_lock is currently more widely used than we
3357 // would like. We are actively migrating Threads_lock uses to other
3358 // mechanisms in order to reduce Threads_lock contention.
3359
3360 JavaThread* Threads::_thread_list = NULL;
3361 int Threads::_number_of_threads = 0;
3362 int Threads::_number_of_non_daemon_threads = 0;
3363 int Threads::_return_code = 0;
3364 int Threads::_thread_claim_parity = 0;
3365 size_t JavaThread::_stack_size_at_create = 0;
3366
3367 #ifdef ASSERT
3368 bool Threads::_vm_complete = false;
3369 #endif
3370
3371 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3372 Prefetch::read((void*)addr, prefetch_interval);
3373 return *addr;
3374 }
3375
3376 // Possibly the ugliest for loop the world has seen. C++ does not allow
3377 // multiple types in the declaration section of the for loop. In this case
3378 // we are only dealing with pointers and hence can cast them. It looks ugly
3379 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3380 #define DO_JAVA_THREADS(LIST, X) \
3381 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3382 *MACRO_list = (JavaThread*)(LIST), \
3383 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3384 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3385 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3386 MACRO_current_p != MACRO_end; \
3387 MACRO_current_p++, \
3388 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3389
3390 // All JavaThreads
3391 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3392
3393 // All non-JavaThreads (i.e., every non-JavaThread in the system).
3394 void Threads::non_java_threads_do(ThreadClosure* tc) {
3395 // Someday we could have a table or list of all non-JavaThreads.
3396 // For now, just manually iterate through them.
3397 tc->do_thread(VMThread::vm_thread());
3398 if (Universe::heap() != NULL) {
3399 Universe::heap()->gc_threads_do(tc);
3400 }
3401 WatcherThread *wt = WatcherThread::watcher_thread();
3402 // Strictly speaking, the following NULL check isn't sufficient to make sure
3403 // the data for WatcherThread is still valid upon being examined. However,
3404 // considering that WatchThread terminates when the VM is on the way to
3405 // exit at safepoint, the chance of the above is extremely small. The right
3406 // way to prevent termination of WatcherThread would be to acquire
3407 // Terminator_lock, but we can't do that without violating the lock rank
3408 // checking in some cases.
3409 if (wt != NULL) {
3410 tc->do_thread(wt);
3411 }
3412
3413 #if INCLUDE_JFR
3414 Thread* sampler_thread = Jfr::sampler_thread();
3415 if (sampler_thread != NULL) {
3416 tc->do_thread(sampler_thread);
3417 }
3418
3419 #endif
3420
3421 // If CompilerThreads ever become non-JavaThreads, add them here
3422 }
3423
3424 // All JavaThreads
3425 void Threads::java_threads_do(ThreadClosure* tc) {
3426 assert_locked_or_safepoint(Threads_lock);
3427 // ALL_JAVA_THREADS iterates through all JavaThreads.
3428 ALL_JAVA_THREADS(p) {
3429 tc->do_thread(p);
3430 }
3431 }
3432
3433 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3434 assert_locked_or_safepoint(Threads_lock);
3435 java_threads_do(tc);
3436 tc->do_thread(VMThread::vm_thread());
3437 }
3438
3439 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3440 void Threads::threads_do(ThreadClosure* tc) {
3441 assert_locked_or_safepoint(Threads_lock);
3442 java_threads_do(tc);
3443 non_java_threads_do(tc);
3444 }
3445
3446 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3447 int cp = Threads::thread_claim_parity();
3448 ALL_JAVA_THREADS(p) {
3449 if (p->claim_oops_do(is_par, cp)) {
3450 tc->do_thread(p);
3451 }
3452 }
3453 VMThread* vmt = VMThread::vm_thread();
3454 if (vmt->claim_oops_do(is_par, cp)) {
3455 tc->do_thread(vmt);
3456 }
3457 }
3458
3459 // The system initialization in the library has three phases.
3460 //
3461 // Phase 1: java.lang.System class initialization
3462 // java.lang.System is a primordial class loaded and initialized
3463 // by the VM early during startup. java.lang.System.<clinit>
3464 // only does registerNatives and keeps the rest of the class
3465 // initialization work later until thread initialization completes.
3466 //
3467 // System.initPhase1 initializes the system properties, the static
3468 // fields in, out, and err. Set up java signal handlers, OS-specific
3469 // system settings, and thread group of the main thread.
3470 static void call_initPhase1(TRAPS) {
3471 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3472 JavaValue result(T_VOID);
3473 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3474 vmSymbols::void_method_signature(), CHECK);
3475 }
3476
3477 // Phase 2. Module system initialization
3478 // This will initialize the module system. Only java.base classes
3479 // can be loaded until phase 2 completes.
3480 //
3481 // Call System.initPhase2 after the compiler initialization and jsr292
3482 // classes get initialized because module initialization runs a lot of java
3483 // code, that for performance reasons, should be compiled. Also, this will
3484 // enable the startup code to use lambda and other language features in this
3485 // phase and onward.
3486 //
3487 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3488 static void call_initPhase2(TRAPS) {
3489 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3490
3491 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3492
3493 JavaValue result(T_INT);
3494 JavaCallArguments args;
3495 args.push_int(DisplayVMOutputToStderr);
3496 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3497 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3498 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3499 if (result.get_jint() != JNI_OK) {
3500 vm_exit_during_initialization(); // no message or exception
3501 }
3502
3503 universe_post_module_init();
3504 }
3505
3506 // Phase 3. final setup - set security manager, system class loader and TCCL
3507 //
3508 // This will instantiate and set the security manager, set the system class
3509 // loader as well as the thread context class loader. The security manager
3510 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3511 // other modules or the application's classpath.
3512 static void call_initPhase3(TRAPS) {
3513 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3514 JavaValue result(T_VOID);
3515 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3516 vmSymbols::void_method_signature(), CHECK);
3517 }
3518
3519 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3520 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3521
3522 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3523 create_vm_init_libraries();
3524 }
3525
3526 initialize_class(vmSymbols::java_lang_String(), CHECK);
3527
3528 // Inject CompactStrings value after the static initializers for String ran.
3529 java_lang_String::set_compact_strings(CompactStrings);
3530
3531 // Initialize java_lang.System (needed before creating the thread)
3532 initialize_class(vmSymbols::java_lang_System(), CHECK);
3533 // The VM creates & returns objects of this class. Make sure it's initialized.
3534 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3535 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3536 Handle thread_group = create_initial_thread_group(CHECK);
3537 Universe::set_main_thread_group(thread_group());
3538 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3539 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3540 main_thread->set_threadObj(thread_object);
3541 // Set thread status to running since main thread has
3542 // been started and running.
3543 java_lang_Thread::set_thread_status(thread_object,
3544 java_lang_Thread::RUNNABLE);
3545
3546 // The VM creates objects of this class.
3547 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3548
3549 // The VM preresolves methods to these classes. Make sure that they get initialized
3550 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3551 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3552
3553 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3554 call_initPhase1(CHECK);
3555
3556 // get the Java runtime name after java.lang.System is initialized
3557 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3558 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3559
3560 // an instance of OutOfMemory exception has been allocated earlier
3561 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3562 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3563 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3564 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3565 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3566 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3567 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3568 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3569 }
3570
3571 void Threads::initialize_jsr292_core_classes(TRAPS) {
3572 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3573
3574 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3575 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3576 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3577 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3578 }
3579
3580 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3581 extern void JDK_Version_init();
3582
3583 // Preinitialize version info.
3584 VM_Version::early_initialize();
3585
3586 // Check version
3587 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3588
3589 // Initialize library-based TLS
3590 ThreadLocalStorage::init();
3591
3592 // Initialize the output stream module
3593 ostream_init();
3594
3595 // Process java launcher properties.
3596 Arguments::process_sun_java_launcher_properties(args);
3597
3598 // Initialize the os module
3599 os::init();
3600
3601 // Record VM creation timing statistics
3602 TraceVmCreationTime create_vm_timer;
3603 create_vm_timer.start();
3604
3605 // Initialize system properties.
3606 Arguments::init_system_properties();
3607
3608 // So that JDK version can be used as a discriminator when parsing arguments
3609 JDK_Version_init();
3610
3611 // Update/Initialize System properties after JDK version number is known
3612 Arguments::init_version_specific_system_properties();
3613
3614 // Make sure to initialize log configuration *before* parsing arguments
3615 LogConfiguration::initialize(create_vm_timer.begin_time());
3616
3617 // Parse arguments
3618 // Note: this internally calls os::init_container_support()
3619 jint parse_result = Arguments::parse(args);
3620 if (parse_result != JNI_OK) return parse_result;
3621
3622 os::init_before_ergo();
3623
3624 jint ergo_result = Arguments::apply_ergo();
3625 if (ergo_result != JNI_OK) return ergo_result;
3626
3627 // Final check of all ranges after ergonomics which may change values.
3628 if (!JVMFlagRangeList::check_ranges()) {
3629 return JNI_EINVAL;
3630 }
3631
3632 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3633 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3634 if (!constraint_result) {
3635 return JNI_EINVAL;
3636 }
3637
3638 JVMFlagWriteableList::mark_startup();
3639
3640 if (PauseAtStartup) {
3641 os::pause();
3642 }
3643
3644 HOTSPOT_VM_INIT_BEGIN();
3645
3646 // Timing (must come after argument parsing)
3647 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3648
3649 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3650 // Initialize assert poison page mechanism.
3651 if (ShowRegistersOnAssert) {
3652 initialize_assert_poison();
3653 }
3654 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3655
3656 // Initialize the os module after parsing the args
3657 jint os_init_2_result = os::init_2();
3658 if (os_init_2_result != JNI_OK) return os_init_2_result;
3659
3660 SafepointMechanism::initialize();
3661
3662 jint adjust_after_os_result = Arguments::adjust_after_os();
3663 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3664
3665 // Initialize output stream logging
3666 ostream_init_log();
3667
3668 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3669 // Must be before create_vm_init_agents()
3670 if (Arguments::init_libraries_at_startup()) {
3671 convert_vm_init_libraries_to_agents();
3672 }
3673
3674 // Launch -agentlib/-agentpath and converted -Xrun agents
3675 if (Arguments::init_agents_at_startup()) {
3676 create_vm_init_agents();
3677 }
3678
3679 // Initialize Threads state
3680 _thread_list = NULL;
3681 _number_of_threads = 0;
3682 _number_of_non_daemon_threads = 0;
3683
3684 // Initialize global data structures and create system classes in heap
3685 vm_init_globals();
3686
3687 #if INCLUDE_JVMCI
3688 if (JVMCICounterSize > 0) {
3689 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3690 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3691 } else {
3692 JavaThread::_jvmci_old_thread_counters = NULL;
3693 }
3694 #endif // INCLUDE_JVMCI
3695
3696 // Attach the main thread to this os thread
3697 JavaThread* main_thread = new JavaThread();
3698 main_thread->set_thread_state(_thread_in_vm);
3699 main_thread->initialize_thread_current();
3700 // must do this before set_active_handles
3701 main_thread->record_stack_base_and_size();
3702 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3703
3704 if (!main_thread->set_as_starting_thread()) {
3705 vm_shutdown_during_initialization(
3706 "Failed necessary internal allocation. Out of swap space");
3707 main_thread->smr_delete();
3708 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3709 return JNI_ENOMEM;
3710 }
3711
3712 // Enable guard page *after* os::create_main_thread(), otherwise it would
3713 // crash Linux VM, see notes in os_linux.cpp.
3714 main_thread->create_stack_guard_pages();
3715
3716 // Initialize Java-Level synchronization subsystem
3717 ObjectMonitor::Initialize();
3718
3719 // Initialize global modules
3720 jint status = init_globals();
3721 if (status != JNI_OK) {
3722 main_thread->smr_delete();
3723 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3724 return status;
3725 }
3726
3727 JFR_ONLY(Jfr::on_vm_init();)
3728
3729 // Should be done after the heap is fully created
3730 main_thread->cache_global_variables();
3731
3732 HandleMark hm;
3733
3734 { MutexLocker mu(Threads_lock);
3735 Threads::add(main_thread);
3736 }
3737
3738 // Any JVMTI raw monitors entered in onload will transition into
3739 // real raw monitor. VM is setup enough here for raw monitor enter.
3740 JvmtiExport::transition_pending_onload_raw_monitors();
3741
3742 // Create the VMThread
3743 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3744
3745 VMThread::create();
3746 Thread* vmthread = VMThread::vm_thread();
3747
3748 if (!os::create_thread(vmthread, os::vm_thread)) {
3749 vm_exit_during_initialization("Cannot create VM thread. "
3750 "Out of system resources.");
3751 }
3752
3753 // Wait for the VM thread to become ready, and VMThread::run to initialize
3754 // Monitors can have spurious returns, must always check another state flag
3755 {
3756 MutexLocker ml(Notify_lock);
3757 os::start_thread(vmthread);
3758 while (vmthread->active_handles() == NULL) {
3759 Notify_lock->wait();
3760 }
3761 }
3762 }
3763
3764 assert(Universe::is_fully_initialized(), "not initialized");
3765 if (VerifyDuringStartup) {
3766 // Make sure we're starting with a clean slate.
3767 VM_Verify verify_op;
3768 VMThread::execute(&verify_op);
3769 }
3770
3771 Thread* THREAD = Thread::current();
3772
3773 // Always call even when there are not JVMTI environments yet, since environments
3774 // may be attached late and JVMTI must track phases of VM execution
3775 JvmtiExport::enter_early_start_phase();
3776
3777 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3778 JvmtiExport::post_early_vm_start();
3779
3780 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3781
3782 // We need this for ClassDataSharing - the initial vm.info property is set
3783 // with the default value of CDS "sharing" which may be reset through
3784 // command line options.
3785 reset_vm_info_property(CHECK_JNI_ERR);
3786
3787 quicken_jni_functions();
3788
3789 // No more stub generation allowed after that point.
3790 StubCodeDesc::freeze();
3791
3792 // Set flag that basic initialization has completed. Used by exceptions and various
3793 // debug stuff, that does not work until all basic classes have been initialized.
3794 set_init_completed();
3795
3796 LogConfiguration::post_initialize();
3797 Metaspace::post_initialize();
3798
3799 HOTSPOT_VM_INIT_END();
3800
3801 // record VM initialization completion time
3802 #if INCLUDE_MANAGEMENT
3803 Management::record_vm_init_completed();
3804 #endif // INCLUDE_MANAGEMENT
3805
3806 // Signal Dispatcher needs to be started before VMInit event is posted
3807 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3808
3809 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3810 if (!DisableAttachMechanism) {
3811 AttachListener::vm_start();
3812 if (StartAttachListener || AttachListener::init_at_startup()) {
3813 AttachListener::init();
3814 }
3815 }
3816
3817 // Launch -Xrun agents
3818 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3819 // back-end can launch with -Xdebug -Xrunjdwp.
3820 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3821 create_vm_init_libraries();
3822 }
3823
3824 if (CleanChunkPoolAsync) {
3825 Chunk::start_chunk_pool_cleaner_task();
3826 }
3827
3828 // initialize compiler(s)
3829 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3830 #if INCLUDE_JVMCI
3831 bool force_JVMCI_intialization = false;
3832 if (EnableJVMCI) {
3833 // Initialize JVMCI eagerly when it is explicitly requested.
3834 // Or when JVMCIPrintProperties is enabled.
3835 // The JVMCI Java initialization code will read this flag and
3836 // do the printing if it's set.
3837 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties;
3838
3839 if (!force_JVMCI_intialization) {
3840 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3841 // compilations via JVMCI will not actually block until JVMCI is initialized.
3842 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3843 }
3844 }
3845 #endif
3846 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
3847 // Postpone completion of compiler initialization to after JVMCI
3848 // is initialized to avoid timeouts of blocking compilations.
3849 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
3850 CompileBroker::compilation_init_phase2();
3851 }
3852 #endif
3853
3854 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3855 // It is done after compilers are initialized, because otherwise compilations of
3856 // signature polymorphic MH intrinsics can be missed
3857 // (see SystemDictionary::find_method_handle_intrinsic).
3858 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3859
3860 // This will initialize the module system. Only java.base classes can be
3861 // loaded until phase 2 completes
3862 call_initPhase2(CHECK_JNI_ERR);
3863
3864 // Always call even when there are not JVMTI environments yet, since environments
3865 // may be attached late and JVMTI must track phases of VM execution
3866 JvmtiExport::enter_start_phase();
3867
3868 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3869 JvmtiExport::post_vm_start();
3870
3871 // Final system initialization including security manager and system class loader
3872 call_initPhase3(CHECK_JNI_ERR);
3873
3874 // cache the system and platform class loaders
3875 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3876
3877 #if INCLUDE_CDS
3878 if (DumpSharedSpaces) {
3879 // capture the module path info from the ModuleEntryTable
3880 ClassLoader::initialize_module_path(THREAD);
3881 }
3882 #endif
3883
3884 #if INCLUDE_JVMCI
3885 if (force_JVMCI_intialization) {
3886 JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
3887 CompileBroker::compilation_init_phase2();
3888 }
3889 #endif
3890
3891 // Always call even when there are not JVMTI environments yet, since environments
3892 // may be attached late and JVMTI must track phases of VM execution
3893 JvmtiExport::enter_live_phase();
3894
3895 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3896 JvmtiExport::post_vm_initialized();
3897
3898 JFR_ONLY(Jfr::on_vm_start();)
3899
3900 #if INCLUDE_MANAGEMENT
3901 Management::initialize(THREAD);
3902
3903 if (HAS_PENDING_EXCEPTION) {
3904 // management agent fails to start possibly due to
3905 // configuration problem and is responsible for printing
3906 // stack trace if appropriate. Simply exit VM.
3907 vm_exit(1);
3908 }
3909 #endif // INCLUDE_MANAGEMENT
3910
3911 if (MemProfiling) MemProfiler::engage();
3912 StatSampler::engage();
3913 if (CheckJNICalls) JniPeriodicChecker::engage();
3914
3915 BiasedLocking::init();
3916
3917 #if INCLUDE_RTM_OPT
3918 RTMLockingCounters::init();
3919 #endif
3920
3921 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3922 call_postVMInitHook(THREAD);
3923 // The Java side of PostVMInitHook.run must deal with all
3924 // exceptions and provide means of diagnosis.
3925 if (HAS_PENDING_EXCEPTION) {
3926 CLEAR_PENDING_EXCEPTION;
3927 }
3928 }
3929
3930 {
3931 MutexLocker ml(PeriodicTask_lock);
3932 // Make sure the WatcherThread can be started by WatcherThread::start()
3933 // or by dynamic enrollment.
3934 WatcherThread::make_startable();
3935 // Start up the WatcherThread if there are any periodic tasks
3936 // NOTE: All PeriodicTasks should be registered by now. If they
3937 // aren't, late joiners might appear to start slowly (we might
3938 // take a while to process their first tick).
3939 if (PeriodicTask::num_tasks() > 0) {
3940 WatcherThread::start();
3941 }
3942 }
3943
3944 create_vm_timer.end();
3945 #ifdef ASSERT
3946 _vm_complete = true;
3947 #endif
3948
3949 if (DumpSharedSpaces) {
3950 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3951 ShouldNotReachHere();
3952 }
3953
3954 return JNI_OK;
3955 }
3956
3957 // type for the Agent_OnLoad and JVM_OnLoad entry points
3958 extern "C" {
3959 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3960 }
3961 // Find a command line agent library and return its entry point for
3962 // -agentlib: -agentpath: -Xrun
3963 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3964 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3965 const char *on_load_symbols[],
3966 size_t num_symbol_entries) {
3967 OnLoadEntry_t on_load_entry = NULL;
3968 void *library = NULL;
3969
3970 if (!agent->valid()) {
3971 char buffer[JVM_MAXPATHLEN];
3972 char ebuf[1024] = "";
3973 const char *name = agent->name();
3974 const char *msg = "Could not find agent library ";
3975
3976 // First check to see if agent is statically linked into executable
3977 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3978 library = agent->os_lib();
3979 } else if (agent->is_absolute_path()) {
3980 library = os::dll_load(name, ebuf, sizeof ebuf);
3981 if (library == NULL) {
3982 const char *sub_msg = " in absolute path, with error: ";
3983 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3984 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3985 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3986 // If we can't find the agent, exit.
3987 vm_exit_during_initialization(buf, NULL);
3988 FREE_C_HEAP_ARRAY(char, buf);
3989 }
3990 } else {
3991 // Try to load the agent from the standard dll directory
3992 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3993 name)) {
3994 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3995 }
3996 if (library == NULL) { // Try the library path directory.
3997 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
3998 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3999 }
4000 if (library == NULL) {
4001 const char *sub_msg = " on the library path, with error: ";
4002 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4003
4004 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4005 strlen(ebuf) + strlen(sub_msg2) + 1;
4006 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4007 if (!agent->is_instrument_lib()) {
4008 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4009 } else {
4010 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4011 }
4012 // If we can't find the agent, exit.
4013 vm_exit_during_initialization(buf, NULL);
4014 FREE_C_HEAP_ARRAY(char, buf);
4015 }
4016 }
4017 }
4018 agent->set_os_lib(library);
4019 agent->set_valid();
4020 }
4021
4022 // Find the OnLoad function.
4023 on_load_entry =
4024 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4025 false,
4026 on_load_symbols,
4027 num_symbol_entries));
4028 return on_load_entry;
4029 }
4030
4031 // Find the JVM_OnLoad entry point
4032 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4033 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4034 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4035 }
4036
4037 // Find the Agent_OnLoad entry point
4038 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4039 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4040 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4041 }
4042
4043 // For backwards compatibility with -Xrun
4044 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4045 // treated like -agentpath:
4046 // Must be called before agent libraries are created
4047 void Threads::convert_vm_init_libraries_to_agents() {
4048 AgentLibrary* agent;
4049 AgentLibrary* next;
4050
4051 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4052 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4053 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4054
4055 // If there is an JVM_OnLoad function it will get called later,
4056 // otherwise see if there is an Agent_OnLoad
4057 if (on_load_entry == NULL) {
4058 on_load_entry = lookup_agent_on_load(agent);
4059 if (on_load_entry != NULL) {
4060 // switch it to the agent list -- so that Agent_OnLoad will be called,
4061 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4062 Arguments::convert_library_to_agent(agent);
4063 } else {
4064 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4065 }
4066 }
4067 }
4068 }
4069
4070 // Create agents for -agentlib: -agentpath: and converted -Xrun
4071 // Invokes Agent_OnLoad
4072 // Called very early -- before JavaThreads exist
4073 void Threads::create_vm_init_agents() {
4074 extern struct JavaVM_ main_vm;
4075 AgentLibrary* agent;
4076
4077 JvmtiExport::enter_onload_phase();
4078
4079 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4080 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4081
4082 if (on_load_entry != NULL) {
4083 // Invoke the Agent_OnLoad function
4084 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4085 if (err != JNI_OK) {
4086 vm_exit_during_initialization("agent library failed to init", agent->name());
4087 }
4088 } else {
4089 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4090 }
4091 }
4092 JvmtiExport::enter_primordial_phase();
4093 }
4094
4095 extern "C" {
4096 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4097 }
4098
4099 void Threads::shutdown_vm_agents() {
4100 // Send any Agent_OnUnload notifications
4101 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4102 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4103 extern struct JavaVM_ main_vm;
4104 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4105
4106 // Find the Agent_OnUnload function.
4107 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4108 os::find_agent_function(agent,
4109 false,
4110 on_unload_symbols,
4111 num_symbol_entries));
4112
4113 // Invoke the Agent_OnUnload function
4114 if (unload_entry != NULL) {
4115 JavaThread* thread = JavaThread::current();
4116 ThreadToNativeFromVM ttn(thread);
4117 HandleMark hm(thread);
4118 (*unload_entry)(&main_vm);
4119 }
4120 }
4121 }
4122
4123 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4124 // Invokes JVM_OnLoad
4125 void Threads::create_vm_init_libraries() {
4126 extern struct JavaVM_ main_vm;
4127 AgentLibrary* agent;
4128
4129 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4130 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4131
4132 if (on_load_entry != NULL) {
4133 // Invoke the JVM_OnLoad function
4134 JavaThread* thread = JavaThread::current();
4135 ThreadToNativeFromVM ttn(thread);
4136 HandleMark hm(thread);
4137 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4138 if (err != JNI_OK) {
4139 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4140 }
4141 } else {
4142 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4143 }
4144 }
4145 }
4146
4147
4148 // Last thread running calls java.lang.Shutdown.shutdown()
4149 void JavaThread::invoke_shutdown_hooks() {
4150 HandleMark hm(this);
4151
4152 // We could get here with a pending exception, if so clear it now.
4153 if (this->has_pending_exception()) {
4154 this->clear_pending_exception();
4155 }
4156
4157 EXCEPTION_MARK;
4158 Klass* shutdown_klass =
4159 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4160 THREAD);
4161 if (shutdown_klass != NULL) {
4162 // SystemDictionary::resolve_or_null will return null if there was
4163 // an exception. If we cannot load the Shutdown class, just don't
4164 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4165 // won't be run. Note that if a shutdown hook was registered,
4166 // the Shutdown class would have already been loaded
4167 // (Runtime.addShutdownHook will load it).
4168 JavaValue result(T_VOID);
4169 JavaCalls::call_static(&result,
4170 shutdown_klass,
4171 vmSymbols::shutdown_method_name(),
4172 vmSymbols::void_method_signature(),
4173 THREAD);
4174 }
4175 CLEAR_PENDING_EXCEPTION;
4176 }
4177
4178 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4179 // the program falls off the end of main(). Another VM exit path is through
4180 // vm_exit() when the program calls System.exit() to return a value or when
4181 // there is a serious error in VM. The two shutdown paths are not exactly
4182 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4183 // and VM_Exit op at VM level.
4184 //
4185 // Shutdown sequence:
4186 // + Shutdown native memory tracking if it is on
4187 // + Wait until we are the last non-daemon thread to execute
4188 // <-- every thing is still working at this moment -->
4189 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4190 // shutdown hooks
4191 // + Call before_exit(), prepare for VM exit
4192 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4193 // currently the only user of this mechanism is File.deleteOnExit())
4194 // > stop StatSampler, watcher thread, CMS threads,
4195 // post thread end and vm death events to JVMTI,
4196 // stop signal thread
4197 // + Call JavaThread::exit(), it will:
4198 // > release JNI handle blocks, remove stack guard pages
4199 // > remove this thread from Threads list
4200 // <-- no more Java code from this thread after this point -->
4201 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4202 // the compiler threads at safepoint
4203 // <-- do not use anything that could get blocked by Safepoint -->
4204 // + Disable tracing at JNI/JVM barriers
4205 // + Set _vm_exited flag for threads that are still running native code
4206 // + Delete this thread
4207 // + Call exit_globals()
4208 // > deletes tty
4209 // > deletes PerfMemory resources
4210 // + Return to caller
4211
4212 bool Threads::destroy_vm() {
4213 JavaThread* thread = JavaThread::current();
4214
4215 #ifdef ASSERT
4216 _vm_complete = false;
4217 #endif
4218 // Wait until we are the last non-daemon thread to execute
4219 { MutexLocker nu(Threads_lock);
4220 while (Threads::number_of_non_daemon_threads() > 1)
4221 // This wait should make safepoint checks, wait without a timeout,
4222 // and wait as a suspend-equivalent condition.
4223 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4224 Mutex::_as_suspend_equivalent_flag);
4225 }
4226
4227 EventShutdown e;
4228 if (e.should_commit()) {
4229 e.set_reason("No remaining non-daemon Java threads");
4230 e.commit();
4231 }
4232
4233 // Hang forever on exit if we are reporting an error.
4234 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4235 os::infinite_sleep();
4236 }
4237 os::wait_for_keypress_at_exit();
4238
4239 // run Java level shutdown hooks
4240 thread->invoke_shutdown_hooks();
4241
4242 before_exit(thread);
4243
4244 thread->exit(true);
4245
4246 // Stop VM thread.
4247 {
4248 // 4945125 The vm thread comes to a safepoint during exit.
4249 // GC vm_operations can get caught at the safepoint, and the
4250 // heap is unparseable if they are caught. Grab the Heap_lock
4251 // to prevent this. The GC vm_operations will not be able to
4252 // queue until after the vm thread is dead. After this point,
4253 // we'll never emerge out of the safepoint before the VM exits.
4254
4255 MutexLocker ml(Heap_lock);
4256
4257 VMThread::wait_for_vm_thread_exit();
4258 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4259 VMThread::destroy();
4260 }
4261
4262 // Now, all Java threads are gone except daemon threads. Daemon threads
4263 // running Java code or in VM are stopped by the Safepoint. However,
4264 // daemon threads executing native code are still running. But they
4265 // will be stopped at native=>Java/VM barriers. Note that we can't
4266 // simply kill or suspend them, as it is inherently deadlock-prone.
4267
4268 VM_Exit::set_vm_exited();
4269
4270 // Clean up ideal graph printers after the VMThread has started
4271 // the final safepoint which will block all the Compiler threads.
4272 // Note that this Thread has already logically exited so the
4273 // clean_up() function's use of a JavaThreadIteratorWithHandle
4274 // would be a problem except set_vm_exited() has remembered the
4275 // shutdown thread which is granted a policy exception.
4276 #if defined(COMPILER2) && !defined(PRODUCT)
4277 IdealGraphPrinter::clean_up();
4278 #endif
4279
4280 notify_vm_shutdown();
4281
4282 // We are after VM_Exit::set_vm_exited() so we can't call
4283 // thread->smr_delete() or we will block on the Threads_lock.
4284 // Deleting the shutdown thread here is safe because another
4285 // JavaThread cannot have an active ThreadsListHandle for
4286 // this JavaThread.
4287 delete thread;
4288
4289 #if INCLUDE_JVMCI
4290 if (JVMCICounterSize > 0) {
4291 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4292 }
4293 #endif
4294
4295 // exit_globals() will delete tty
4296 exit_globals();
4297
4298 LogConfiguration::finalize();
4299
4300 return true;
4301 }
4302
4303
4304 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4305 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4306 return is_supported_jni_version(version);
4307 }
4308
4309
4310 jboolean Threads::is_supported_jni_version(jint version) {
4311 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4312 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4313 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4314 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4315 if (version == JNI_VERSION_9) return JNI_TRUE;
4316 if (version == JNI_VERSION_10) return JNI_TRUE;
4317 return JNI_FALSE;
4318 }
4319
4320
4321 void Threads::add(JavaThread* p, bool force_daemon) {
4322 // The threads lock must be owned at this point
4323 assert_locked_or_safepoint(Threads_lock);
4324
4325 BarrierSet::barrier_set()->on_thread_attach(p);
4326
4327 p->set_next(_thread_list);
4328 _thread_list = p;
4329
4330 // Once a JavaThread is added to the Threads list, smr_delete() has
4331 // to be used to delete it. Otherwise we can just delete it directly.
4332 p->set_on_thread_list();
4333
4334 _number_of_threads++;
4335 oop threadObj = p->threadObj();
4336 bool daemon = true;
4337 // Bootstrapping problem: threadObj can be null for initial
4338 // JavaThread (or for threads attached via JNI)
4339 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4340 _number_of_non_daemon_threads++;
4341 daemon = false;
4342 }
4343
4344 ThreadService::add_thread(p, daemon);
4345
4346 // Maintain fast thread list
4347 ThreadsSMRSupport::add_thread(p);
4348
4349 // Possible GC point.
4350 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4351 }
4352
4353 void Threads::remove(JavaThread* p) {
4354
4355 // Reclaim the objectmonitors from the omInUseList and omFreeList of the moribund thread.
4356 ObjectSynchronizer::omFlush(p);
4357
4358 // Extra scope needed for Thread_lock, so we can check
4359 // that we do not remove thread without safepoint code notice
4360 { MutexLocker ml(Threads_lock);
4361
4362 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4363
4364 // Maintain fast thread list
4365 ThreadsSMRSupport::remove_thread(p);
4366
4367 JavaThread* current = _thread_list;
4368 JavaThread* prev = NULL;
4369
4370 while (current != p) {
4371 prev = current;
4372 current = current->next();
4373 }
4374
4375 if (prev) {
4376 prev->set_next(current->next());
4377 } else {
4378 _thread_list = p->next();
4379 }
4380
4381 _number_of_threads--;
4382 oop threadObj = p->threadObj();
4383 bool daemon = true;
4384 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4385 _number_of_non_daemon_threads--;
4386 daemon = false;
4387
4388 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4389 // on destroy_vm will wake up.
4390 if (number_of_non_daemon_threads() == 1) {
4391 Threads_lock->notify_all();
4392 }
4393 }
4394 ThreadService::remove_thread(p, daemon);
4395
4396 // Make sure that safepoint code disregard this thread. This is needed since
4397 // the thread might mess around with locks after this point. This can cause it
4398 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4399 // of this thread since it is removed from the queue.
4400 p->set_terminated_value();
4401 } // unlock Threads_lock
4402
4403 // Since Events::log uses a lock, we grab it outside the Threads_lock
4404 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4405 }
4406
4407 // Operations on the Threads list for GC. These are not explicitly locked,
4408 // but the garbage collector must provide a safe context for them to run.
4409 // In particular, these things should never be called when the Threads_lock
4410 // is held by some other thread. (Note: the Safepoint abstraction also
4411 // uses the Threads_lock to guarantee this property. It also makes sure that
4412 // all threads gets blocked when exiting or starting).
4413
4414 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4415 ALL_JAVA_THREADS(p) {
4416 p->oops_do(f, cf);
4417 }
4418 VMThread::vm_thread()->oops_do(f, cf);
4419 }
4420
4421 void Threads::change_thread_claim_parity() {
4422 // Set the new claim parity.
4423 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4424 "Not in range.");
4425 _thread_claim_parity++;
4426 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4427 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4428 "Not in range.");
4429 }
4430
4431 #ifdef ASSERT
4432 void Threads::assert_all_threads_claimed() {
4433 ALL_JAVA_THREADS(p) {
4434 const int thread_parity = p->oops_do_parity();
4435 assert((thread_parity == _thread_claim_parity),
4436 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4437 }
4438 VMThread* vmt = VMThread::vm_thread();
4439 const int thread_parity = vmt->oops_do_parity();
4440 assert((thread_parity == _thread_claim_parity),
4441 "VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
4442 }
4443 #endif // ASSERT
4444
4445 class ParallelOopsDoThreadClosure : public ThreadClosure {
4446 private:
4447 OopClosure* _f;
4448 CodeBlobClosure* _cf;
4449 public:
4450 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4451 void do_thread(Thread* t) {
4452 t->oops_do(_f, _cf);
4453 }
4454 };
4455
4456 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4457 ParallelOopsDoThreadClosure tc(f, cf);
4458 possibly_parallel_threads_do(is_par, &tc);
4459 }
4460
4461 void Threads::nmethods_do(CodeBlobClosure* cf) {
4462 ALL_JAVA_THREADS(p) {
4463 // This is used by the code cache sweeper to mark nmethods that are active
4464 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4465 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4466 if(!p->is_Code_cache_sweeper_thread()) {
4467 p->nmethods_do(cf);
4468 }
4469 }
4470 }
4471
4472 void Threads::metadata_do(void f(Metadata*)) {
4473 ALL_JAVA_THREADS(p) {
4474 p->metadata_do(f);
4475 }
4476 }
4477
4478 class ThreadHandlesClosure : public ThreadClosure {
4479 void (*_f)(Metadata*);
4480 public:
4481 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4482 virtual void do_thread(Thread* thread) {
4483 thread->metadata_handles_do(_f);
4484 }
4485 };
4486
4487 void Threads::metadata_handles_do(void f(Metadata*)) {
4488 // Only walk the Handles in Thread.
4489 ThreadHandlesClosure handles_closure(f);
4490 threads_do(&handles_closure);
4491 }
4492
4493 void Threads::deoptimized_wrt_marked_nmethods() {
4494 ALL_JAVA_THREADS(p) {
4495 p->deoptimized_wrt_marked_nmethods();
4496 }
4497 }
4498
4499
4500 // Get count Java threads that are waiting to enter the specified monitor.
4501 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4502 int count,
4503 address monitor) {
4504 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4505
4506 int i = 0;
4507 DO_JAVA_THREADS(t_list, p) {
4508 if (!p->can_call_java()) continue;
4509
4510 address pending = (address)p->current_pending_monitor();
4511 if (pending == monitor) { // found a match
4512 if (i < count) result->append(p); // save the first count matches
4513 i++;
4514 }
4515 }
4516
4517 return result;
4518 }
4519
4520
4521 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4522 address owner) {
4523 // NULL owner means not locked so we can skip the search
4524 if (owner == NULL) return NULL;
4525
4526 DO_JAVA_THREADS(t_list, p) {
4527 // first, see if owner is the address of a Java thread
4528 if (owner == (address)p) return p;
4529 }
4530
4531 // Cannot assert on lack of success here since this function may be
4532 // used by code that is trying to report useful problem information
4533 // like deadlock detection.
4534 if (UseHeavyMonitors) return NULL;
4535
4536 // If we didn't find a matching Java thread and we didn't force use of
4537 // heavyweight monitors, then the owner is the stack address of the
4538 // Lock Word in the owning Java thread's stack.
4539 //
4540 JavaThread* the_owner = NULL;
4541 DO_JAVA_THREADS(t_list, q) {
4542 if (q->is_lock_owned(owner)) {
4543 the_owner = q;
4544 break;
4545 }
4546 }
4547
4548 // cannot assert on lack of success here; see above comment
4549 return the_owner;
4550 }
4551
4552 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4553 void Threads::print_on(outputStream* st, bool print_stacks,
4554 bool internal_format, bool print_concurrent_locks) {
4555 char buf[32];
4556 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4557
4558 st->print_cr("Full thread dump %s (%s %s):",
4559 Abstract_VM_Version::vm_name(),
4560 Abstract_VM_Version::vm_release(),
4561 Abstract_VM_Version::vm_info_string());
4562 st->cr();
4563
4564 #if INCLUDE_SERVICES
4565 // Dump concurrent locks
4566 ConcurrentLocksDump concurrent_locks;
4567 if (print_concurrent_locks) {
4568 concurrent_locks.dump_at_safepoint();
4569 }
4570 #endif // INCLUDE_SERVICES
4571
4572 ThreadsSMRSupport::print_info_on(st);
4573 st->cr();
4574
4575 ALL_JAVA_THREADS(p) {
4576 ResourceMark rm;
4577 p->print_on(st);
4578 if (print_stacks) {
4579 if (internal_format) {
4580 p->trace_stack();
4581 } else {
4582 p->print_stack_on(st);
4583 }
4584 }
4585 st->cr();
4586 #if INCLUDE_SERVICES
4587 if (print_concurrent_locks) {
4588 concurrent_locks.print_locks_on(p, st);
4589 }
4590 #endif // INCLUDE_SERVICES
4591 }
4592
4593 VMThread::vm_thread()->print_on(st);
4594 st->cr();
4595 Universe::heap()->print_gc_threads_on(st);
4596 WatcherThread* wt = WatcherThread::watcher_thread();
4597 if (wt != NULL) {
4598 wt->print_on(st);
4599 st->cr();
4600 }
4601
4602 st->flush();
4603 }
4604
4605 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4606 int buflen, bool* found_current) {
4607 if (this_thread != NULL) {
4608 bool is_current = (current == this_thread);
4609 *found_current = *found_current || is_current;
4610 st->print("%s", is_current ? "=>" : " ");
4611
4612 st->print(PTR_FORMAT, p2i(this_thread));
4613 st->print(" ");
4614 this_thread->print_on_error(st, buf, buflen);
4615 st->cr();
4616 }
4617 }
4618
4619 class PrintOnErrorClosure : public ThreadClosure {
4620 outputStream* _st;
4621 Thread* _current;
4622 char* _buf;
4623 int _buflen;
4624 bool* _found_current;
4625 public:
4626 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4627 int buflen, bool* found_current) :
4628 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4629
4630 virtual void do_thread(Thread* thread) {
4631 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4632 }
4633 };
4634
4635 // Threads::print_on_error() is called by fatal error handler. It's possible
4636 // that VM is not at safepoint and/or current thread is inside signal handler.
4637 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4638 // memory (even in resource area), it might deadlock the error handler.
4639 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4640 int buflen) {
4641 ThreadsSMRSupport::print_info_on(st);
4642 st->cr();
4643
4644 bool found_current = false;
4645 st->print_cr("Java Threads: ( => current thread )");
4646 ALL_JAVA_THREADS(thread) {
4647 print_on_error(thread, st, current, buf, buflen, &found_current);
4648 }
4649 st->cr();
4650
4651 st->print_cr("Other Threads:");
4652 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4653 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4654
4655 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4656 Universe::heap()->gc_threads_do(&print_closure);
4657
4658 if (!found_current) {
4659 st->cr();
4660 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4661 current->print_on_error(st, buf, buflen);
4662 st->cr();
4663 }
4664 st->cr();
4665
4666 st->print_cr("Threads with active compile tasks:");
4667 print_threads_compiling(st, buf, buflen);
4668 }
4669
4670 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) {
4671 ALL_JAVA_THREADS(thread) {
4672 if (thread->is_Compiler_thread()) {
4673 CompilerThread* ct = (CompilerThread*) thread;
4674
4675 // Keep task in local variable for NULL check.
4676 // ct->_task might be set to NULL by concurring compiler thread
4677 // because it completed the compilation. The task is never freed,
4678 // though, just returned to a free list.
4679 CompileTask* task = ct->task();
4680 if (task != NULL) {
4681 thread->print_name_on_error(st, buf, buflen);
4682 task->print(st, NULL, true, true);
4683 }
4684 }
4685 }
4686 }
4687
4688
4689 // Internal SpinLock and Mutex
4690 // Based on ParkEvent
4691
4692 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4693 //
4694 // We employ SpinLocks _only for low-contention, fixed-length
4695 // short-duration critical sections where we're concerned
4696 // about native mutex_t or HotSpot Mutex:: latency.
4697 // The mux construct provides a spin-then-block mutual exclusion
4698 // mechanism.
4699 //
4700 // Testing has shown that contention on the ListLock guarding gFreeList
4701 // is common. If we implement ListLock as a simple SpinLock it's common
4702 // for the JVM to devolve to yielding with little progress. This is true
4703 // despite the fact that the critical sections protected by ListLock are
4704 // extremely short.
4705 //
4706 // TODO-FIXME: ListLock should be of type SpinLock.
4707 // We should make this a 1st-class type, integrated into the lock
4708 // hierarchy as leaf-locks. Critically, the SpinLock structure
4709 // should have sufficient padding to avoid false-sharing and excessive
4710 // cache-coherency traffic.
4711
4712
4713 typedef volatile int SpinLockT;
4714
4715 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4716 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4717 return; // normal fast-path return
4718 }
4719
4720 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4721 TEVENT(SpinAcquire - ctx);
4722 int ctr = 0;
4723 int Yields = 0;
4724 for (;;) {
4725 while (*adr != 0) {
4726 ++ctr;
4727 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4728 if (Yields > 5) {
4729 os::naked_short_sleep(1);
4730 } else {
4731 os::naked_yield();
4732 ++Yields;
4733 }
4734 } else {
4735 SpinPause();
4736 }
4737 }
4738 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4739 }
4740 }
4741
4742 void Thread::SpinRelease(volatile int * adr) {
4743 assert(*adr != 0, "invariant");
4744 OrderAccess::fence(); // guarantee at least release consistency.
4745 // Roach-motel semantics.
4746 // It's safe if subsequent LDs and STs float "up" into the critical section,
4747 // but prior LDs and STs within the critical section can't be allowed
4748 // to reorder or float past the ST that releases the lock.
4749 // Loads and stores in the critical section - which appear in program
4750 // order before the store that releases the lock - must also appear
4751 // before the store that releases the lock in memory visibility order.
4752 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4753 // the ST of 0 into the lock-word which releases the lock, so fence
4754 // more than covers this on all platforms.
4755 *adr = 0;
4756 }
4757
4758 // muxAcquire and muxRelease:
4759 //
4760 // * muxAcquire and muxRelease support a single-word lock-word construct.
4761 // The LSB of the word is set IFF the lock is held.
4762 // The remainder of the word points to the head of a singly-linked list
4763 // of threads blocked on the lock.
4764 //
4765 // * The current implementation of muxAcquire-muxRelease uses its own
4766 // dedicated Thread._MuxEvent instance. If we're interested in
4767 // minimizing the peak number of extant ParkEvent instances then
4768 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4769 // as certain invariants were satisfied. Specifically, care would need
4770 // to be taken with regards to consuming unpark() "permits".
4771 // A safe rule of thumb is that a thread would never call muxAcquire()
4772 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4773 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4774 // consume an unpark() permit intended for monitorenter, for instance.
4775 // One way around this would be to widen the restricted-range semaphore
4776 // implemented in park(). Another alternative would be to provide
4777 // multiple instances of the PlatformEvent() for each thread. One
4778 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4779 //
4780 // * Usage:
4781 // -- Only as leaf locks
4782 // -- for short-term locking only as muxAcquire does not perform
4783 // thread state transitions.
4784 //
4785 // Alternatives:
4786 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4787 // but with parking or spin-then-park instead of pure spinning.
4788 // * Use Taura-Oyama-Yonenzawa locks.
4789 // * It's possible to construct a 1-0 lock if we encode the lockword as
4790 // (List,LockByte). Acquire will CAS the full lockword while Release
4791 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4792 // acquiring threads use timers (ParkTimed) to detect and recover from
4793 // the stranding window. Thread/Node structures must be aligned on 256-byte
4794 // boundaries by using placement-new.
4795 // * Augment MCS with advisory back-link fields maintained with CAS().
4796 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4797 // The validity of the backlinks must be ratified before we trust the value.
4798 // If the backlinks are invalid the exiting thread must back-track through the
4799 // the forward links, which are always trustworthy.
4800 // * Add a successor indication. The LockWord is currently encoded as
4801 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4802 // to provide the usual futile-wakeup optimization.
4803 // See RTStt for details.
4804 // * Consider schedctl.sc_nopreempt to cover the critical section.
4805 //
4806
4807
4808 const intptr_t LOCKBIT = 1;
4809
4810 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4811 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4812 if (w == 0) return;
4813 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4814 return;
4815 }
4816
4817 TEVENT(muxAcquire - Contention);
4818 ParkEvent * const Self = Thread::current()->_MuxEvent;
4819 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4820 for (;;) {
4821 int its = (os::is_MP() ? 100 : 0) + 1;
4822
4823 // Optional spin phase: spin-then-park strategy
4824 while (--its >= 0) {
4825 w = *Lock;
4826 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4827 return;
4828 }
4829 }
4830
4831 Self->reset();
4832 Self->OnList = intptr_t(Lock);
4833 // The following fence() isn't _strictly necessary as the subsequent
4834 // CAS() both serializes execution and ratifies the fetched *Lock value.
4835 OrderAccess::fence();
4836 for (;;) {
4837 w = *Lock;
4838 if ((w & LOCKBIT) == 0) {
4839 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4840 Self->OnList = 0; // hygiene - allows stronger asserts
4841 return;
4842 }
4843 continue; // Interference -- *Lock changed -- Just retry
4844 }
4845 assert(w & LOCKBIT, "invariant");
4846 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4847 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4848 }
4849
4850 while (Self->OnList != 0) {
4851 Self->park();
4852 }
4853 }
4854 }
4855
4856 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4857 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4858 if (w == 0) return;
4859 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4860 return;
4861 }
4862
4863 TEVENT(muxAcquire - Contention);
4864 ParkEvent * ReleaseAfter = NULL;
4865 if (ev == NULL) {
4866 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4867 }
4868 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4869 for (;;) {
4870 guarantee(ev->OnList == 0, "invariant");
4871 int its = (os::is_MP() ? 100 : 0) + 1;
4872
4873 // Optional spin phase: spin-then-park strategy
4874 while (--its >= 0) {
4875 w = *Lock;
4876 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4877 if (ReleaseAfter != NULL) {
4878 ParkEvent::Release(ReleaseAfter);
4879 }
4880 return;
4881 }
4882 }
4883
4884 ev->reset();
4885 ev->OnList = intptr_t(Lock);
4886 // The following fence() isn't _strictly necessary as the subsequent
4887 // CAS() both serializes execution and ratifies the fetched *Lock value.
4888 OrderAccess::fence();
4889 for (;;) {
4890 w = *Lock;
4891 if ((w & LOCKBIT) == 0) {
4892 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4893 ev->OnList = 0;
4894 // We call ::Release while holding the outer lock, thus
4895 // artificially lengthening the critical section.
4896 // Consider deferring the ::Release() until the subsequent unlock(),
4897 // after we've dropped the outer lock.
4898 if (ReleaseAfter != NULL) {
4899 ParkEvent::Release(ReleaseAfter);
4900 }
4901 return;
4902 }
4903 continue; // Interference -- *Lock changed -- Just retry
4904 }
4905 assert(w & LOCKBIT, "invariant");
4906 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4907 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4908 }
4909
4910 while (ev->OnList != 0) {
4911 ev->park();
4912 }
4913 }
4914 }
4915
4916 // Release() must extract a successor from the list and then wake that thread.
4917 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4918 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4919 // Release() would :
4920 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4921 // (B) Extract a successor from the private list "in-hand"
4922 // (C) attempt to CAS() the residual back into *Lock over null.
4923 // If there were any newly arrived threads and the CAS() would fail.
4924 // In that case Release() would detach the RATs, re-merge the list in-hand
4925 // with the RATs and repeat as needed. Alternately, Release() might
4926 // detach and extract a successor, but then pass the residual list to the wakee.
4927 // The wakee would be responsible for reattaching and remerging before it
4928 // competed for the lock.
4929 //
4930 // Both "pop" and DMR are immune from ABA corruption -- there can be
4931 // multiple concurrent pushers, but only one popper or detacher.
4932 // This implementation pops from the head of the list. This is unfair,
4933 // but tends to provide excellent throughput as hot threads remain hot.
4934 // (We wake recently run threads first).
4935 //
4936 // All paths through muxRelease() will execute a CAS.
4937 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4938 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4939 // executed within the critical section are complete and globally visible before the
4940 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4941 void Thread::muxRelease(volatile intptr_t * Lock) {
4942 for (;;) {
4943 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
4944 assert(w & LOCKBIT, "invariant");
4945 if (w == LOCKBIT) return;
4946 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4947 assert(List != NULL, "invariant");
4948 assert(List->OnList == intptr_t(Lock), "invariant");
4949 ParkEvent * const nxt = List->ListNext;
4950 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4951
4952 // The following CAS() releases the lock and pops the head element.
4953 // The CAS() also ratifies the previously fetched lock-word value.
4954 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
4955 continue;
4956 }
4957 List->OnList = 0;
4958 OrderAccess::fence();
4959 List->unpark();
4960 return;
4961 }
4962 }
4963
4964
4965 void Threads::verify() {
4966 ALL_JAVA_THREADS(p) {
4967 p->verify();
4968 }
4969 VMThread* thread = VMThread::vm_thread();
4970 if (thread != NULL) thread->verify();
4971 }