1 /*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/moduleEntry.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/vmSymbols.hpp"
32 #include "code/codeCache.hpp"
33 #include "code/scopeDesc.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "compiler/compileTask.hpp"
36 #include "gc/shared/gcId.hpp"
37 #include "gc/shared/gcLocker.inline.hpp"
38 #include "gc/shared/workgroup.hpp"
39 #include "interpreter/interpreter.hpp"
40 #include "interpreter/linkResolver.hpp"
41 #include "interpreter/oopMapCache.hpp"
42 #include "jvmtifiles/jvmtiEnv.hpp"
43 #include "logging/log.hpp"
44 #include "logging/logConfiguration.hpp"
45 #include "logging/logStream.hpp"
46 #include "memory/metaspaceShared.hpp"
47 #include "memory/oopFactory.hpp"
48 #include "memory/resourceArea.hpp"
49 #include "memory/universe.inline.hpp"
50 #include "oops/instanceKlass.hpp"
51 #include "oops/objArrayOop.hpp"
52 #include "oops/oop.inline.hpp"
53 #include "oops/symbol.hpp"
54 #include "oops/verifyOopClosure.hpp"
55 #include "prims/jvm_misc.hpp"
56 #include "prims/jvmtiExport.hpp"
57 #include "prims/jvmtiThreadState.hpp"
58 #include "prims/privilegedStack.hpp"
59 #include "runtime/arguments.hpp"
60 #include "runtime/atomic.hpp"
61 #include "runtime/biasedLocking.hpp"
62 #include "runtime/commandLineFlagConstraintList.hpp"
63 #include "runtime/commandLineFlagWriteableList.hpp"
64 #include "runtime/commandLineFlagRangeList.hpp"
65 #include "runtime/deoptimization.hpp"
66 #include "runtime/frame.inline.hpp"
67 #include "runtime/globals.hpp"
68 #include "runtime/handshake.hpp"
69 #include "runtime/init.hpp"
70 #include "runtime/interfaceSupport.hpp"
71 #include "runtime/java.hpp"
72 #include "runtime/javaCalls.hpp"
73 #include "runtime/jniPeriodicChecker.hpp"
74 #include "runtime/memprofiler.hpp"
75 #include "runtime/mutexLocker.hpp"
76 #include "runtime/objectMonitor.hpp"
77 #include "runtime/orderAccess.inline.hpp"
78 #include "runtime/osThread.hpp"
79 #include "runtime/prefetch.inline.hpp"
80 #include "runtime/safepoint.hpp"
81 #include "runtime/safepointMechanism.inline.hpp"
82 #include "runtime/sharedRuntime.hpp"
83 #include "runtime/statSampler.hpp"
84 #include "runtime/stubRoutines.hpp"
85 #include "runtime/sweeper.hpp"
86 #include "runtime/task.hpp"
87 #include "runtime/thread.inline.hpp"
88 #include "runtime/threadCritical.hpp"
89 #include "runtime/threadSMR.inline.hpp"
90 #include "runtime/timer.hpp"
91 #include "runtime/timerTrace.hpp"
92 #include "runtime/vframe.hpp"
93 #include "runtime/vframeArray.hpp"
94 #include "runtime/vframe_hp.hpp"
95 #include "runtime/vmThread.hpp"
96 #include "runtime/vm_operations.hpp"
97 #include "runtime/vm_version.hpp"
98 #include "services/attachListener.hpp"
99 #include "services/management.hpp"
100 #include "services/memTracker.hpp"
101 #include "services/threadService.hpp"
102 #include "trace/traceMacros.hpp"
103 #include "trace/tracing.hpp"
104 #include "utilities/align.hpp"
105 #include "utilities/defaultStream.hpp"
106 #include "utilities/dtrace.hpp"
107 #include "utilities/events.hpp"
108 #include "utilities/macros.hpp"
109 #include "utilities/preserveException.hpp"
110 #include "utilities/vmError.hpp"
111 #if INCLUDE_ALL_GCS
112 #include "gc/cms/concurrentMarkSweepThread.hpp"
113 #include "gc/g1/concurrentMarkThread.inline.hpp"
114 #include "gc/parallel/pcTasks.hpp"
115 #endif // INCLUDE_ALL_GCS
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
132 // Initialization after module runtime initialization
133 void universe_post_module_init(); // must happen after call_initPhase2
134
135 #ifdef DTRACE_ENABLED
136
137 // Only bother with this argument setup if dtrace is available
138
139 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
140 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
141
142 #define DTRACE_THREAD_PROBE(probe, javathread) \
143 { \
144 ResourceMark rm(this); \
145 int len = 0; \
146 const char* name = (javathread)->get_thread_name(); \
147 len = strlen(name); \
148 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
149 (char *) name, len, \
150 java_lang_Thread::thread_id((javathread)->threadObj()), \
151 (uintptr_t) (javathread)->osthread()->thread_id(), \
152 java_lang_Thread::is_daemon((javathread)->threadObj())); \
153 }
154
155 #else // ndef DTRACE_ENABLED
156
157 #define DTRACE_THREAD_PROBE(probe, javathread)
158
159 #endif // ndef DTRACE_ENABLED
160
161 #ifndef USE_LIBRARY_BASED_TLS_ONLY
162 // Current thread is maintained as a thread-local variable
163 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
164 #endif
165 // Class hierarchy
166 // - Thread
167 // - VMThread
168 // - WatcherThread
169 // - ConcurrentMarkSweepThread
170 // - JavaThread
171 // - CompilerThread
172
173 // ======= Thread ========
174 // Support for forcing alignment of thread objects for biased locking
175 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
176 if (UseBiasedLocking) {
177 const int alignment = markOopDesc::biased_lock_alignment;
178 size_t aligned_size = size + (alignment - sizeof(intptr_t));
179 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
180 : AllocateHeap(aligned_size, flags, CURRENT_PC,
181 AllocFailStrategy::RETURN_NULL);
182 void* aligned_addr = align_up(real_malloc_addr, alignment);
183 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
184 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
185 "JavaThread alignment code overflowed allocated storage");
186 if (aligned_addr != real_malloc_addr) {
187 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
188 p2i(real_malloc_addr),
189 p2i(aligned_addr));
190 }
191 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
192 return aligned_addr;
193 } else {
194 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
195 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
196 }
197 }
198
199 void Thread::operator delete(void* p) {
200 if (UseBiasedLocking) {
201 FreeHeap(((Thread*) p)->_real_malloc_address);
202 } else {
203 FreeHeap(p);
204 }
205 }
206
207 void JavaThread::smr_delete() {
208 if (_on_thread_list) {
209 ThreadsSMRSupport::smr_delete(this);
210 } else {
211 delete this;
212 }
213 }
214
215 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
216 // JavaThread
217
218
219 Thread::Thread() {
220 // stack and get_thread
221 set_stack_base(NULL);
222 set_stack_size(0);
223 set_self_raw_id(0);
224 set_lgrp_id(-1);
225 DEBUG_ONLY(clear_suspendible_thread();)
226
227 // allocated data structures
228 set_osthread(NULL);
229 set_resource_area(new (mtThread)ResourceArea());
230 DEBUG_ONLY(_current_resource_mark = NULL;)
231 set_handle_area(new (mtThread) HandleArea(NULL));
232 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
233 set_active_handles(NULL);
234 set_free_handle_block(NULL);
235 set_last_handle_mark(NULL);
236
237 // This initial value ==> never claimed.
238 _oops_do_parity = 0;
239 _threads_hazard_ptr = NULL;
240 _nested_threads_hazard_ptr = NULL;
241 _nested_threads_hazard_ptr_cnt = 0;
242
243 // the handle mark links itself to last_handle_mark
244 new HandleMark(this);
245
246 // plain initialization
247 debug_only(_owned_locks = NULL;)
248 debug_only(_allow_allocation_count = 0;)
249 NOT_PRODUCT(_allow_safepoint_count = 0;)
250 NOT_PRODUCT(_skip_gcalot = false;)
251 _jvmti_env_iteration_count = 0;
252 set_allocated_bytes(0);
253 _vm_operation_started_count = 0;
254 _vm_operation_completed_count = 0;
255 _current_pending_monitor = NULL;
256 _current_pending_monitor_is_from_java = true;
257 _current_waiting_monitor = NULL;
258 _num_nested_signal = 0;
259 omFreeList = NULL;
260 omFreeCount = 0;
261 omFreeProvision = 32;
262 omInUseList = NULL;
263 omInUseCount = 0;
264 _bytes_until_sample = 0;
265
266 #ifdef ASSERT
267 _visited_for_critical_count = false;
268 #endif
269
270 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
271 Monitor::_safepoint_check_sometimes);
272 _suspend_flags = 0;
273
274 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
275 _hashStateX = os::random();
276 _hashStateY = 842502087;
277 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
278 _hashStateW = 273326509;
279
280 _OnTrap = 0;
281 _schedctl = NULL;
282 _Stalled = 0;
283 _TypeTag = 0x2BAD;
284
285 // Many of the following fields are effectively final - immutable
286 // Note that nascent threads can't use the Native Monitor-Mutex
287 // construct until the _MutexEvent is initialized ...
288 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
289 // we might instead use a stack of ParkEvents that we could provision on-demand.
290 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
291 // and ::Release()
292 _ParkEvent = ParkEvent::Allocate(this);
293 _SleepEvent = ParkEvent::Allocate(this);
294 _MutexEvent = ParkEvent::Allocate(this);
295 _MuxEvent = ParkEvent::Allocate(this);
296
297 #ifdef CHECK_UNHANDLED_OOPS
298 if (CheckUnhandledOops) {
299 _unhandled_oops = new UnhandledOops(this);
300 }
301 #endif // CHECK_UNHANDLED_OOPS
302 #ifdef ASSERT
303 if (UseBiasedLocking) {
304 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
305 assert(this == _real_malloc_address ||
306 this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
307 "bug in forced alignment of thread objects");
308 }
309 #endif // ASSERT
310 }
311
312 void Thread::initialize_thread_current() {
313 #ifndef USE_LIBRARY_BASED_TLS_ONLY
314 assert(_thr_current == NULL, "Thread::current already initialized");
315 _thr_current = this;
316 #endif
317 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
318 ThreadLocalStorage::set_thread(this);
319 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
320 }
321
322 void Thread::clear_thread_current() {
323 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
324 #ifndef USE_LIBRARY_BASED_TLS_ONLY
325 _thr_current = NULL;
326 #endif
327 ThreadLocalStorage::set_thread(NULL);
328 }
329
330 void Thread::record_stack_base_and_size() {
331 set_stack_base(os::current_stack_base());
332 set_stack_size(os::current_stack_size());
333 // CR 7190089: on Solaris, primordial thread's stack is adjusted
334 // in initialize_thread(). Without the adjustment, stack size is
335 // incorrect if stack is set to unlimited (ulimit -s unlimited).
336 // So far, only Solaris has real implementation of initialize_thread().
337 //
338 // set up any platform-specific state.
339 os::initialize_thread(this);
340
341 // Set stack limits after thread is initialized.
342 if (is_Java_thread()) {
343 ((JavaThread*) this)->set_stack_overflow_limit();
344 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
345 }
346 #if INCLUDE_NMT
347 // record thread's native stack, stack grows downward
348 MemTracker::record_thread_stack(stack_end(), stack_size());
349 #endif // INCLUDE_NMT
350 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
351 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
352 os::current_thread_id(), p2i(stack_base() - stack_size()),
353 p2i(stack_base()), stack_size()/1024);
354 }
355
356
357 Thread::~Thread() {
358 EVENT_THREAD_DESTRUCT(this);
359
360 // stack_base can be NULL if the thread is never started or exited before
361 // record_stack_base_and_size called. Although, we would like to ensure
362 // that all started threads do call record_stack_base_and_size(), there is
363 // not proper way to enforce that.
364 #if INCLUDE_NMT
365 if (_stack_base != NULL) {
366 MemTracker::release_thread_stack(stack_end(), stack_size());
367 #ifdef ASSERT
368 set_stack_base(NULL);
369 #endif
370 }
371 #endif // INCLUDE_NMT
372
373 // deallocate data structures
374 delete resource_area();
375 // since the handle marks are using the handle area, we have to deallocated the root
376 // handle mark before deallocating the thread's handle area,
377 assert(last_handle_mark() != NULL, "check we have an element");
378 delete last_handle_mark();
379 assert(last_handle_mark() == NULL, "check we have reached the end");
380
381 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
382 // We NULL out the fields for good hygiene.
383 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
384 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
385 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
386 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
387
388 delete handle_area();
389 delete metadata_handles();
390
391 // SR_handler uses this as a termination indicator -
392 // needs to happen before os::free_thread()
393 delete _SR_lock;
394 _SR_lock = NULL;
395
396 // osthread() can be NULL, if creation of thread failed.
397 if (osthread() != NULL) os::free_thread(osthread());
398
399 // clear Thread::current if thread is deleting itself.
400 // Needed to ensure JNI correctly detects non-attached threads.
401 if (this == Thread::current()) {
402 clear_thread_current();
403 }
404
405 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
406 }
407
408 // NOTE: dummy function for assertion purpose.
409 void Thread::run() {
410 ShouldNotReachHere();
411 }
412
413 #ifdef ASSERT
414 // A JavaThread is considered "dangling" if it is not the current
415 // thread, has been added the Threads list, the system is not at a
416 // safepoint and the Thread is not "protected".
417 //
418 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
419 assert(!thread->is_Java_thread() || Thread::current() == thread ||
420 !((JavaThread *) thread)->on_thread_list() ||
421 SafepointSynchronize::is_at_safepoint() ||
422 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
423 "possibility of dangling Thread pointer");
424 }
425 #endif
426
427 ThreadPriority Thread::get_priority(const Thread* const thread) {
428 ThreadPriority priority;
429 // Can return an error!
430 (void)os::get_priority(thread, priority);
431 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
432 return priority;
433 }
434
435 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
436 debug_only(check_for_dangling_thread_pointer(thread);)
437 // Can return an error!
438 (void)os::set_priority(thread, priority);
439 }
440
441
442 void Thread::start(Thread* thread) {
443 // Start is different from resume in that its safety is guaranteed by context or
444 // being called from a Java method synchronized on the Thread object.
445 if (!DisableStartThread) {
446 if (thread->is_Java_thread()) {
447 // Initialize the thread state to RUNNABLE before starting this thread.
448 // Can not set it after the thread started because we do not know the
449 // exact thread state at that time. It could be in MONITOR_WAIT or
450 // in SLEEPING or some other state.
451 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
452 java_lang_Thread::RUNNABLE);
453 }
454 os::start_thread(thread);
455 }
456 }
457
458 // Enqueue a VM_Operation to do the job for us - sometime later
459 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
460 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
461 VMThread::execute(vm_stop);
462 }
463
464
465 // Check if an external suspend request has completed (or has been
466 // cancelled). Returns true if the thread is externally suspended and
467 // false otherwise.
468 //
469 // The bits parameter returns information about the code path through
470 // the routine. Useful for debugging:
471 //
472 // set in is_ext_suspend_completed():
473 // 0x00000001 - routine was entered
474 // 0x00000010 - routine return false at end
475 // 0x00000100 - thread exited (return false)
476 // 0x00000200 - suspend request cancelled (return false)
477 // 0x00000400 - thread suspended (return true)
478 // 0x00001000 - thread is in a suspend equivalent state (return true)
479 // 0x00002000 - thread is native and walkable (return true)
480 // 0x00004000 - thread is native_trans and walkable (needed retry)
481 //
482 // set in wait_for_ext_suspend_completion():
483 // 0x00010000 - routine was entered
484 // 0x00020000 - suspend request cancelled before loop (return false)
485 // 0x00040000 - thread suspended before loop (return true)
486 // 0x00080000 - suspend request cancelled in loop (return false)
487 // 0x00100000 - thread suspended in loop (return true)
488 // 0x00200000 - suspend not completed during retry loop (return false)
489
490 // Helper class for tracing suspend wait debug bits.
491 //
492 // 0x00000100 indicates that the target thread exited before it could
493 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
494 // 0x00080000 each indicate a cancelled suspend request so they don't
495 // count as wait failures either.
496 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
497
498 class TraceSuspendDebugBits : public StackObj {
499 private:
500 JavaThread * jt;
501 bool is_wait;
502 bool called_by_wait; // meaningful when !is_wait
503 uint32_t * bits;
504
505 public:
506 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
507 uint32_t *_bits) {
508 jt = _jt;
509 is_wait = _is_wait;
510 called_by_wait = _called_by_wait;
511 bits = _bits;
512 }
513
514 ~TraceSuspendDebugBits() {
515 if (!is_wait) {
516 #if 1
517 // By default, don't trace bits for is_ext_suspend_completed() calls.
518 // That trace is very chatty.
519 return;
520 #else
521 if (!called_by_wait) {
522 // If tracing for is_ext_suspend_completed() is enabled, then only
523 // trace calls to it from wait_for_ext_suspend_completion()
524 return;
525 }
526 #endif
527 }
528
529 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
530 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
531 MutexLocker ml(Threads_lock); // needed for get_thread_name()
532 ResourceMark rm;
533
534 tty->print_cr(
535 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
536 jt->get_thread_name(), *bits);
537
538 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
539 }
540 }
541 }
542 };
543 #undef DEBUG_FALSE_BITS
544
545
546 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
547 uint32_t *bits) {
548 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
549
550 bool did_trans_retry = false; // only do thread_in_native_trans retry once
551 bool do_trans_retry; // flag to force the retry
552
553 *bits |= 0x00000001;
554
555 do {
556 do_trans_retry = false;
557
558 if (is_exiting()) {
559 // Thread is in the process of exiting. This is always checked
560 // first to reduce the risk of dereferencing a freed JavaThread.
561 *bits |= 0x00000100;
562 return false;
563 }
564
565 if (!is_external_suspend()) {
566 // Suspend request is cancelled. This is always checked before
567 // is_ext_suspended() to reduce the risk of a rogue resume
568 // confusing the thread that made the suspend request.
569 *bits |= 0x00000200;
570 return false;
571 }
572
573 if (is_ext_suspended()) {
574 // thread is suspended
575 *bits |= 0x00000400;
576 return true;
577 }
578
579 // Now that we no longer do hard suspends of threads running
580 // native code, the target thread can be changing thread state
581 // while we are in this routine:
582 //
583 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
584 //
585 // We save a copy of the thread state as observed at this moment
586 // and make our decision about suspend completeness based on the
587 // copy. This closes the race where the thread state is seen as
588 // _thread_in_native_trans in the if-thread_blocked check, but is
589 // seen as _thread_blocked in if-thread_in_native_trans check.
590 JavaThreadState save_state = thread_state();
591
592 if (save_state == _thread_blocked && is_suspend_equivalent()) {
593 // If the thread's state is _thread_blocked and this blocking
594 // condition is known to be equivalent to a suspend, then we can
595 // consider the thread to be externally suspended. This means that
596 // the code that sets _thread_blocked has been modified to do
597 // self-suspension if the blocking condition releases. We also
598 // used to check for CONDVAR_WAIT here, but that is now covered by
599 // the _thread_blocked with self-suspension check.
600 //
601 // Return true since we wouldn't be here unless there was still an
602 // external suspend request.
603 *bits |= 0x00001000;
604 return true;
605 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
606 // Threads running native code will self-suspend on native==>VM/Java
607 // transitions. If its stack is walkable (should always be the case
608 // unless this function is called before the actual java_suspend()
609 // call), then the wait is done.
610 *bits |= 0x00002000;
611 return true;
612 } else if (!called_by_wait && !did_trans_retry &&
613 save_state == _thread_in_native_trans &&
614 frame_anchor()->walkable()) {
615 // The thread is transitioning from thread_in_native to another
616 // thread state. check_safepoint_and_suspend_for_native_trans()
617 // will force the thread to self-suspend. If it hasn't gotten
618 // there yet we may have caught the thread in-between the native
619 // code check above and the self-suspend. Lucky us. If we were
620 // called by wait_for_ext_suspend_completion(), then it
621 // will be doing the retries so we don't have to.
622 //
623 // Since we use the saved thread state in the if-statement above,
624 // there is a chance that the thread has already transitioned to
625 // _thread_blocked by the time we get here. In that case, we will
626 // make a single unnecessary pass through the logic below. This
627 // doesn't hurt anything since we still do the trans retry.
628
629 *bits |= 0x00004000;
630
631 // Once the thread leaves thread_in_native_trans for another
632 // thread state, we break out of this retry loop. We shouldn't
633 // need this flag to prevent us from getting back here, but
634 // sometimes paranoia is good.
635 did_trans_retry = true;
636
637 // We wait for the thread to transition to a more usable state.
638 for (int i = 1; i <= SuspendRetryCount; i++) {
639 // We used to do an "os::yield_all(i)" call here with the intention
640 // that yielding would increase on each retry. However, the parameter
641 // is ignored on Linux which means the yield didn't scale up. Waiting
642 // on the SR_lock below provides a much more predictable scale up for
643 // the delay. It also provides a simple/direct point to check for any
644 // safepoint requests from the VMThread
645
646 // temporarily drops SR_lock while doing wait with safepoint check
647 // (if we're a JavaThread - the WatcherThread can also call this)
648 // and increase delay with each retry
649 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
650
651 // check the actual thread state instead of what we saved above
652 if (thread_state() != _thread_in_native_trans) {
653 // the thread has transitioned to another thread state so
654 // try all the checks (except this one) one more time.
655 do_trans_retry = true;
656 break;
657 }
658 } // end retry loop
659
660
661 }
662 } while (do_trans_retry);
663
664 *bits |= 0x00000010;
665 return false;
666 }
667
668 // Wait for an external suspend request to complete (or be cancelled).
669 // Returns true if the thread is externally suspended and false otherwise.
670 //
671 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
672 uint32_t *bits) {
673 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
674 false /* !called_by_wait */, bits);
675
676 // local flag copies to minimize SR_lock hold time
677 bool is_suspended;
678 bool pending;
679 uint32_t reset_bits;
680
681 // set a marker so is_ext_suspend_completed() knows we are the caller
682 *bits |= 0x00010000;
683
684 // We use reset_bits to reinitialize the bits value at the top of
685 // each retry loop. This allows the caller to make use of any
686 // unused bits for their own marking purposes.
687 reset_bits = *bits;
688
689 {
690 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
691 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
692 delay, bits);
693 pending = is_external_suspend();
694 }
695 // must release SR_lock to allow suspension to complete
696
697 if (!pending) {
698 // A cancelled suspend request is the only false return from
699 // is_ext_suspend_completed() that keeps us from entering the
700 // retry loop.
701 *bits |= 0x00020000;
702 return false;
703 }
704
705 if (is_suspended) {
706 *bits |= 0x00040000;
707 return true;
708 }
709
710 for (int i = 1; i <= retries; i++) {
711 *bits = reset_bits; // reinit to only track last retry
712
713 // We used to do an "os::yield_all(i)" call here with the intention
714 // that yielding would increase on each retry. However, the parameter
715 // is ignored on Linux which means the yield didn't scale up. Waiting
716 // on the SR_lock below provides a much more predictable scale up for
717 // the delay. It also provides a simple/direct point to check for any
718 // safepoint requests from the VMThread
719
720 {
721 MutexLocker ml(SR_lock());
722 // wait with safepoint check (if we're a JavaThread - the WatcherThread
723 // can also call this) and increase delay with each retry
724 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
725
726 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
727 delay, bits);
728
729 // It is possible for the external suspend request to be cancelled
730 // (by a resume) before the actual suspend operation is completed.
731 // Refresh our local copy to see if we still need to wait.
732 pending = is_external_suspend();
733 }
734
735 if (!pending) {
736 // A cancelled suspend request is the only false return from
737 // is_ext_suspend_completed() that keeps us from staying in the
738 // retry loop.
739 *bits |= 0x00080000;
740 return false;
741 }
742
743 if (is_suspended) {
744 *bits |= 0x00100000;
745 return true;
746 }
747 } // end retry loop
748
749 // thread did not suspend after all our retries
750 *bits |= 0x00200000;
751 return false;
752 }
753
754 // Called from API entry points which perform stack walking. If the
755 // associated JavaThread is the current thread, then wait_for_suspend
756 // is not used. Otherwise, it determines if we should wait for the
757 // "other" thread to complete external suspension. (NOTE: in future
758 // releases the suspension mechanism should be reimplemented so this
759 // is not necessary.)
760 //
761 bool
762 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
763 if (this != JavaThread::current()) {
764 // "other" threads require special handling.
765 if (wait_for_suspend) {
766 // We are allowed to wait for the external suspend to complete
767 // so give the other thread a chance to get suspended.
768 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
769 SuspendRetryDelay, bits)) {
770 // Didn't make it so let the caller know.
771 return false;
772 }
773 }
774 // We aren't allowed to wait for the external suspend to complete
775 // so if the other thread isn't externally suspended we need to
776 // let the caller know.
777 else if (!is_ext_suspend_completed_with_lock(bits)) {
778 return false;
779 }
780 }
781
782 return true;
783 }
784
785 #ifndef PRODUCT
786 void JavaThread::record_jump(address target, address instr, const char* file,
787 int line) {
788
789 // This should not need to be atomic as the only way for simultaneous
790 // updates is via interrupts. Even then this should be rare or non-existent
791 // and we don't care that much anyway.
792
793 int index = _jmp_ring_index;
794 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
795 _jmp_ring[index]._target = (intptr_t) target;
796 _jmp_ring[index]._instruction = (intptr_t) instr;
797 _jmp_ring[index]._file = file;
798 _jmp_ring[index]._line = line;
799 }
800 #endif // PRODUCT
801
802 void Thread::interrupt(Thread* thread) {
803 debug_only(check_for_dangling_thread_pointer(thread);)
804 os::interrupt(thread);
805 }
806
807 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
808 debug_only(check_for_dangling_thread_pointer(thread);)
809 // Note: If clear_interrupted==false, this simply fetches and
810 // returns the value of the field osthread()->interrupted().
811 return os::is_interrupted(thread, clear_interrupted);
812 }
813
814
815 // GC Support
816 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
817 int thread_parity = _oops_do_parity;
818 if (thread_parity != strong_roots_parity) {
819 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
820 if (res == thread_parity) {
821 return true;
822 } else {
823 guarantee(res == strong_roots_parity, "Or else what?");
824 return false;
825 }
826 }
827 return false;
828 }
829
830 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
831 active_handles()->oops_do(f);
832 // Do oop for ThreadShadow
833 f->do_oop((oop*)&_pending_exception);
834 handle_area()->oops_do(f);
835
836 if (MonitorInUseLists) {
837 // When using thread local monitor lists, we scan them here,
838 // and the remaining global monitors in ObjectSynchronizer::oops_do().
839 ObjectSynchronizer::thread_local_used_oops_do(this, f);
840 }
841 }
842
843 void Thread::metadata_handles_do(void f(Metadata*)) {
844 // Only walk the Handles in Thread.
845 if (metadata_handles() != NULL) {
846 for (int i = 0; i< metadata_handles()->length(); i++) {
847 f(metadata_handles()->at(i));
848 }
849 }
850 }
851
852 void Thread::print_on(outputStream* st) const {
853 // get_priority assumes osthread initialized
854 if (osthread() != NULL) {
855 int os_prio;
856 if (os::get_native_priority(this, &os_prio) == OS_OK) {
857 st->print("os_prio=%d ", os_prio);
858 }
859 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
860 ext().print_on(st);
861 osthread()->print_on(st);
862 }
863 if (_threads_hazard_ptr != NULL) {
864 st->print("_threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
865 }
866 if (_nested_threads_hazard_ptr != NULL) {
867 print_nested_threads_hazard_ptrs_on(st);
868 }
869 st->print(" ");
870 debug_only(if (WizardMode) print_owned_locks_on(st);)
871 }
872
873 void Thread::print_nested_threads_hazard_ptrs_on(outputStream* st) const {
874 assert(_nested_threads_hazard_ptr != NULL, "must be set to print");
875
876 if (EnableThreadSMRStatistics) {
877 st->print(", _nested_threads_hazard_ptr_cnt=%u", _nested_threads_hazard_ptr_cnt);
878 }
879 st->print(", _nested_threads_hazard_ptrs=");
880 for (NestedThreadsList* node = _nested_threads_hazard_ptr; node != NULL;
881 node = node->next()) {
882 if (node != _nested_threads_hazard_ptr) {
883 // First node does not need a comma-space separator.
884 st->print(", ");
885 }
886 st->print(INTPTR_FORMAT, p2i(node->t_list()));
887 }
888 }
889
890 // Thread::print_on_error() is called by fatal error handler. Don't use
891 // any lock or allocate memory.
892 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
893 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
894
895 if (is_VM_thread()) { st->print("VMThread"); }
896 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
897 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
898 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
899 else { st->print("Thread"); }
900
901 if (is_Named_thread()) {
902 st->print(" \"%s\"", name());
903 }
904
905 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
906 p2i(stack_end()), p2i(stack_base()));
907
908 if (osthread()) {
909 st->print(" [id=%d]", osthread()->thread_id());
910 }
911
912 if (_threads_hazard_ptr != NULL) {
913 st->print(" _threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
914 }
915 if (_nested_threads_hazard_ptr != NULL) {
916 print_nested_threads_hazard_ptrs_on(st);
917 }
918 }
919
920 void Thread::print_value_on(outputStream* st) const {
921 if (is_Named_thread()) {
922 st->print(" \"%s\" ", name());
923 }
924 st->print(INTPTR_FORMAT, p2i(this)); // print address
925 }
926
927 #ifdef ASSERT
928 void Thread::print_owned_locks_on(outputStream* st) const {
929 Monitor *cur = _owned_locks;
930 if (cur == NULL) {
931 st->print(" (no locks) ");
932 } else {
933 st->print_cr(" Locks owned:");
934 while (cur) {
935 cur->print_on(st);
936 cur = cur->next();
937 }
938 }
939 }
940
941 static int ref_use_count = 0;
942
943 bool Thread::owns_locks_but_compiled_lock() const {
944 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
945 if (cur != Compile_lock) return true;
946 }
947 return false;
948 }
949
950
951 #endif
952
953 #ifndef PRODUCT
954
955 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
956 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
957 // no threads which allow_vm_block's are held
958 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
959 // Check if current thread is allowed to block at a safepoint
960 if (!(_allow_safepoint_count == 0)) {
961 fatal("Possible safepoint reached by thread that does not allow it");
962 }
963 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
964 fatal("LEAF method calling lock?");
965 }
966
967 #ifdef ASSERT
968 if (potential_vm_operation && is_Java_thread()
969 && !Universe::is_bootstrapping()) {
970 // Make sure we do not hold any locks that the VM thread also uses.
971 // This could potentially lead to deadlocks
972 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
973 // Threads_lock is special, since the safepoint synchronization will not start before this is
974 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
975 // since it is used to transfer control between JavaThreads and the VMThread
976 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
977 if ((cur->allow_vm_block() &&
978 cur != Threads_lock &&
979 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
980 cur != VMOperationRequest_lock &&
981 cur != VMOperationQueue_lock) ||
982 cur->rank() == Mutex::special) {
983 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
984 }
985 }
986 }
987
988 if (GCALotAtAllSafepoints) {
989 // We could enter a safepoint here and thus have a gc
990 InterfaceSupport::check_gc_alot();
991 }
992 #endif
993 }
994 #endif
995
996 bool Thread::is_in_stack(address adr) const {
997 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
998 address end = os::current_stack_pointer();
999 // Allow non Java threads to call this without stack_base
1000 if (_stack_base == NULL) return true;
1001 if (stack_base() >= adr && adr >= end) return true;
1002
1003 return false;
1004 }
1005
1006 bool Thread::is_in_usable_stack(address adr) const {
1007 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1008 size_t usable_stack_size = _stack_size - stack_guard_size;
1009
1010 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1011 }
1012
1013
1014 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1015 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1016 // used for compilation in the future. If that change is made, the need for these methods
1017 // should be revisited, and they should be removed if possible.
1018
1019 bool Thread::is_lock_owned(address adr) const {
1020 return on_local_stack(adr);
1021 }
1022
1023 bool Thread::set_as_starting_thread() {
1024 // NOTE: this must be called inside the main thread.
1025 return os::create_main_thread((JavaThread*)this);
1026 }
1027
1028 static void initialize_class(Symbol* class_name, TRAPS) {
1029 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1030 InstanceKlass::cast(klass)->initialize(CHECK);
1031 }
1032
1033
1034 // Creates the initial ThreadGroup
1035 static Handle create_initial_thread_group(TRAPS) {
1036 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1037 InstanceKlass* ik = InstanceKlass::cast(k);
1038
1039 Handle system_instance = ik->allocate_instance_handle(CHECK_NH);
1040 {
1041 JavaValue result(T_VOID);
1042 JavaCalls::call_special(&result,
1043 system_instance,
1044 ik,
1045 vmSymbols::object_initializer_name(),
1046 vmSymbols::void_method_signature(),
1047 CHECK_NH);
1048 }
1049 Universe::set_system_thread_group(system_instance());
1050
1051 Handle main_instance = ik->allocate_instance_handle(CHECK_NH);
1052 {
1053 JavaValue result(T_VOID);
1054 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1055 JavaCalls::call_special(&result,
1056 main_instance,
1057 ik,
1058 vmSymbols::object_initializer_name(),
1059 vmSymbols::threadgroup_string_void_signature(),
1060 system_instance,
1061 string,
1062 CHECK_NH);
1063 }
1064 return main_instance;
1065 }
1066
1067 // Creates the initial Thread
1068 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1069 TRAPS) {
1070 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1071 InstanceKlass* ik = InstanceKlass::cast(k);
1072 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1073
1074 java_lang_Thread::set_thread(thread_oop(), thread);
1075 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1076 thread->set_threadObj(thread_oop());
1077
1078 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1079
1080 JavaValue result(T_VOID);
1081 JavaCalls::call_special(&result, thread_oop,
1082 ik,
1083 vmSymbols::object_initializer_name(),
1084 vmSymbols::threadgroup_string_void_signature(),
1085 thread_group,
1086 string,
1087 CHECK_NULL);
1088 return thread_oop();
1089 }
1090
1091 char java_runtime_name[128] = "";
1092 char java_runtime_version[128] = "";
1093
1094 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1095 static const char* get_java_runtime_name(TRAPS) {
1096 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1097 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1098 fieldDescriptor fd;
1099 bool found = k != NULL &&
1100 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1101 vmSymbols::string_signature(), &fd);
1102 if (found) {
1103 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1104 if (name_oop == NULL) {
1105 return NULL;
1106 }
1107 const char* name = java_lang_String::as_utf8_string(name_oop,
1108 java_runtime_name,
1109 sizeof(java_runtime_name));
1110 return name;
1111 } else {
1112 return NULL;
1113 }
1114 }
1115
1116 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1117 static const char* get_java_runtime_version(TRAPS) {
1118 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1119 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1120 fieldDescriptor fd;
1121 bool found = k != NULL &&
1122 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1123 vmSymbols::string_signature(), &fd);
1124 if (found) {
1125 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1126 if (name_oop == NULL) {
1127 return NULL;
1128 }
1129 const char* name = java_lang_String::as_utf8_string(name_oop,
1130 java_runtime_version,
1131 sizeof(java_runtime_version));
1132 return name;
1133 } else {
1134 return NULL;
1135 }
1136 }
1137
1138 // General purpose hook into Java code, run once when the VM is initialized.
1139 // The Java library method itself may be changed independently from the VM.
1140 static void call_postVMInitHook(TRAPS) {
1141 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1142 if (klass != NULL) {
1143 JavaValue result(T_VOID);
1144 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1145 vmSymbols::void_method_signature(),
1146 CHECK);
1147 }
1148 }
1149
1150 static void reset_vm_info_property(TRAPS) {
1151 // the vm info string
1152 ResourceMark rm(THREAD);
1153 const char *vm_info = VM_Version::vm_info_string();
1154
1155 // java.lang.System class
1156 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1157
1158 // setProperty arguments
1159 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1160 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1161
1162 // return value
1163 JavaValue r(T_OBJECT);
1164
1165 // public static String setProperty(String key, String value);
1166 JavaCalls::call_static(&r,
1167 klass,
1168 vmSymbols::setProperty_name(),
1169 vmSymbols::string_string_string_signature(),
1170 key_str,
1171 value_str,
1172 CHECK);
1173 }
1174
1175
1176 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1177 bool daemon, TRAPS) {
1178 assert(thread_group.not_null(), "thread group should be specified");
1179 assert(threadObj() == NULL, "should only create Java thread object once");
1180
1181 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1182 InstanceKlass* ik = InstanceKlass::cast(k);
1183 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1184
1185 java_lang_Thread::set_thread(thread_oop(), this);
1186 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1187 set_threadObj(thread_oop());
1188
1189 JavaValue result(T_VOID);
1190 if (thread_name != NULL) {
1191 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1192 // Thread gets assigned specified name and null target
1193 JavaCalls::call_special(&result,
1194 thread_oop,
1195 ik,
1196 vmSymbols::object_initializer_name(),
1197 vmSymbols::threadgroup_string_void_signature(),
1198 thread_group, // Argument 1
1199 name, // Argument 2
1200 THREAD);
1201 } else {
1202 // Thread gets assigned name "Thread-nnn" and null target
1203 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1204 JavaCalls::call_special(&result,
1205 thread_oop,
1206 ik,
1207 vmSymbols::object_initializer_name(),
1208 vmSymbols::threadgroup_runnable_void_signature(),
1209 thread_group, // Argument 1
1210 Handle(), // Argument 2
1211 THREAD);
1212 }
1213
1214
1215 if (daemon) {
1216 java_lang_Thread::set_daemon(thread_oop());
1217 }
1218
1219 if (HAS_PENDING_EXCEPTION) {
1220 return;
1221 }
1222
1223 Klass* group = SystemDictionary::ThreadGroup_klass();
1224 Handle threadObj(THREAD, this->threadObj());
1225
1226 JavaCalls::call_special(&result,
1227 thread_group,
1228 group,
1229 vmSymbols::add_method_name(),
1230 vmSymbols::thread_void_signature(),
1231 threadObj, // Arg 1
1232 THREAD);
1233 }
1234
1235 // NamedThread -- non-JavaThread subclasses with multiple
1236 // uniquely named instances should derive from this.
1237 NamedThread::NamedThread() : Thread() {
1238 _name = NULL;
1239 _processed_thread = NULL;
1240 _gc_id = GCId::undefined();
1241 }
1242
1243 NamedThread::~NamedThread() {
1244 if (_name != NULL) {
1245 FREE_C_HEAP_ARRAY(char, _name);
1246 _name = NULL;
1247 }
1248 }
1249
1250 void NamedThread::set_name(const char* format, ...) {
1251 guarantee(_name == NULL, "Only get to set name once.");
1252 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1253 guarantee(_name != NULL, "alloc failure");
1254 va_list ap;
1255 va_start(ap, format);
1256 jio_vsnprintf(_name, max_name_len, format, ap);
1257 va_end(ap);
1258 }
1259
1260 void NamedThread::initialize_named_thread() {
1261 set_native_thread_name(name());
1262 }
1263
1264 void NamedThread::print_on(outputStream* st) const {
1265 st->print("\"%s\" ", name());
1266 Thread::print_on(st);
1267 st->cr();
1268 }
1269
1270
1271 // ======= WatcherThread ========
1272
1273 // The watcher thread exists to simulate timer interrupts. It should
1274 // be replaced by an abstraction over whatever native support for
1275 // timer interrupts exists on the platform.
1276
1277 WatcherThread* WatcherThread::_watcher_thread = NULL;
1278 bool WatcherThread::_startable = false;
1279 volatile bool WatcherThread::_should_terminate = false;
1280
1281 WatcherThread::WatcherThread() : Thread() {
1282 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1283 if (os::create_thread(this, os::watcher_thread)) {
1284 _watcher_thread = this;
1285
1286 // Set the watcher thread to the highest OS priority which should not be
1287 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1288 // is created. The only normal thread using this priority is the reference
1289 // handler thread, which runs for very short intervals only.
1290 // If the VMThread's priority is not lower than the WatcherThread profiling
1291 // will be inaccurate.
1292 os::set_priority(this, MaxPriority);
1293 if (!DisableStartThread) {
1294 os::start_thread(this);
1295 }
1296 }
1297 }
1298
1299 int WatcherThread::sleep() const {
1300 // The WatcherThread does not participate in the safepoint protocol
1301 // for the PeriodicTask_lock because it is not a JavaThread.
1302 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1303
1304 if (_should_terminate) {
1305 // check for termination before we do any housekeeping or wait
1306 return 0; // we did not sleep.
1307 }
1308
1309 // remaining will be zero if there are no tasks,
1310 // causing the WatcherThread to sleep until a task is
1311 // enrolled
1312 int remaining = PeriodicTask::time_to_wait();
1313 int time_slept = 0;
1314
1315 // we expect this to timeout - we only ever get unparked when
1316 // we should terminate or when a new task has been enrolled
1317 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1318
1319 jlong time_before_loop = os::javaTimeNanos();
1320
1321 while (true) {
1322 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1323 remaining);
1324 jlong now = os::javaTimeNanos();
1325
1326 if (remaining == 0) {
1327 // if we didn't have any tasks we could have waited for a long time
1328 // consider the time_slept zero and reset time_before_loop
1329 time_slept = 0;
1330 time_before_loop = now;
1331 } else {
1332 // need to recalculate since we might have new tasks in _tasks
1333 time_slept = (int) ((now - time_before_loop) / 1000000);
1334 }
1335
1336 // Change to task list or spurious wakeup of some kind
1337 if (timedout || _should_terminate) {
1338 break;
1339 }
1340
1341 remaining = PeriodicTask::time_to_wait();
1342 if (remaining == 0) {
1343 // Last task was just disenrolled so loop around and wait until
1344 // another task gets enrolled
1345 continue;
1346 }
1347
1348 remaining -= time_slept;
1349 if (remaining <= 0) {
1350 break;
1351 }
1352 }
1353
1354 return time_slept;
1355 }
1356
1357 void WatcherThread::run() {
1358 assert(this == watcher_thread(), "just checking");
1359
1360 this->record_stack_base_and_size();
1361 this->set_native_thread_name(this->name());
1362 this->set_active_handles(JNIHandleBlock::allocate_block());
1363 while (true) {
1364 assert(watcher_thread() == Thread::current(), "thread consistency check");
1365 assert(watcher_thread() == this, "thread consistency check");
1366
1367 // Calculate how long it'll be until the next PeriodicTask work
1368 // should be done, and sleep that amount of time.
1369 int time_waited = sleep();
1370
1371 if (VMError::is_error_reported()) {
1372 // A fatal error has happened, the error handler(VMError::report_and_die)
1373 // should abort JVM after creating an error log file. However in some
1374 // rare cases, the error handler itself might deadlock. Here periodically
1375 // check for error reporting timeouts, and if it happens, just proceed to
1376 // abort the VM.
1377
1378 // This code is in WatcherThread because WatcherThread wakes up
1379 // periodically so the fatal error handler doesn't need to do anything;
1380 // also because the WatcherThread is less likely to crash than other
1381 // threads.
1382
1383 for (;;) {
1384 // Note: we use naked sleep in this loop because we want to avoid using
1385 // any kind of VM infrastructure which may be broken at this point.
1386 if (VMError::check_timeout()) {
1387 // We hit error reporting timeout. Error reporting was interrupted and
1388 // will be wrapping things up now (closing files etc). Give it some more
1389 // time, then quit the VM.
1390 os::naked_short_sleep(200);
1391 // Print a message to stderr.
1392 fdStream err(defaultStream::output_fd());
1393 err.print_raw_cr("# [ timer expired, abort... ]");
1394 // skip atexit/vm_exit/vm_abort hooks
1395 os::die();
1396 }
1397
1398 // Wait a second, then recheck for timeout.
1399 os::naked_short_sleep(999);
1400 }
1401 }
1402
1403 if (_should_terminate) {
1404 // check for termination before posting the next tick
1405 break;
1406 }
1407
1408 PeriodicTask::real_time_tick(time_waited);
1409 }
1410
1411 // Signal that it is terminated
1412 {
1413 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1414 _watcher_thread = NULL;
1415 Terminator_lock->notify();
1416 }
1417 }
1418
1419 void WatcherThread::start() {
1420 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1421
1422 if (watcher_thread() == NULL && _startable) {
1423 _should_terminate = false;
1424 // Create the single instance of WatcherThread
1425 new WatcherThread();
1426 }
1427 }
1428
1429 void WatcherThread::make_startable() {
1430 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1431 _startable = true;
1432 }
1433
1434 void WatcherThread::stop() {
1435 {
1436 // Follow normal safepoint aware lock enter protocol since the
1437 // WatcherThread is stopped by another JavaThread.
1438 MutexLocker ml(PeriodicTask_lock);
1439 _should_terminate = true;
1440
1441 WatcherThread* watcher = watcher_thread();
1442 if (watcher != NULL) {
1443 // unpark the WatcherThread so it can see that it should terminate
1444 watcher->unpark();
1445 }
1446 }
1447
1448 MutexLocker mu(Terminator_lock);
1449
1450 while (watcher_thread() != NULL) {
1451 // This wait should make safepoint checks, wait without a timeout,
1452 // and wait as a suspend-equivalent condition.
1453 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1454 Mutex::_as_suspend_equivalent_flag);
1455 }
1456 }
1457
1458 void WatcherThread::unpark() {
1459 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1460 PeriodicTask_lock->notify();
1461 }
1462
1463 void WatcherThread::print_on(outputStream* st) const {
1464 st->print("\"%s\" ", name());
1465 Thread::print_on(st);
1466 st->cr();
1467 }
1468
1469 // ======= JavaThread ========
1470
1471 #if INCLUDE_JVMCI
1472
1473 jlong* JavaThread::_jvmci_old_thread_counters;
1474
1475 bool jvmci_counters_include(JavaThread* thread) {
1476 oop threadObj = thread->threadObj();
1477 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1478 }
1479
1480 void JavaThread::collect_counters(typeArrayOop array) {
1481 if (JVMCICounterSize > 0) {
1482 MutexLocker tl(Threads_lock);
1483 JavaThreadIteratorWithHandle jtiwh;
1484 for (int i = 0; i < array->length(); i++) {
1485 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1486 }
1487 for (; JavaThread *tp = jtiwh.next(); ) {
1488 if (jvmci_counters_include(tp)) {
1489 for (int i = 0; i < array->length(); i++) {
1490 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1491 }
1492 }
1493 }
1494 }
1495 }
1496
1497 #endif // INCLUDE_JVMCI
1498
1499 // A JavaThread is a normal Java thread
1500
1501 void JavaThread::initialize() {
1502 // Initialize fields
1503
1504 set_saved_exception_pc(NULL);
1505 set_threadObj(NULL);
1506 _anchor.clear();
1507 set_entry_point(NULL);
1508 set_jni_functions(jni_functions());
1509 set_callee_target(NULL);
1510 set_vm_result(NULL);
1511 set_vm_result_2(NULL);
1512 set_vframe_array_head(NULL);
1513 set_vframe_array_last(NULL);
1514 set_deferred_locals(NULL);
1515 set_deopt_mark(NULL);
1516 set_deopt_compiled_method(NULL);
1517 clear_must_deopt_id();
1518 set_monitor_chunks(NULL);
1519 set_next(NULL);
1520 _on_thread_list = false;
1521 set_thread_state(_thread_new);
1522 _terminated = _not_terminated;
1523 _privileged_stack_top = NULL;
1524 _array_for_gc = NULL;
1525 _suspend_equivalent = false;
1526 _in_deopt_handler = 0;
1527 _doing_unsafe_access = false;
1528 _stack_guard_state = stack_guard_unused;
1529 #if INCLUDE_JVMCI
1530 _pending_monitorenter = false;
1531 _pending_deoptimization = -1;
1532 _pending_failed_speculation = NULL;
1533 _pending_transfer_to_interpreter = false;
1534 _adjusting_comp_level = false;
1535 _jvmci._alternate_call_target = NULL;
1536 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1537 if (JVMCICounterSize > 0) {
1538 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1539 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1540 } else {
1541 _jvmci_counters = NULL;
1542 }
1543 #endif // INCLUDE_JVMCI
1544 _reserved_stack_activation = NULL; // stack base not known yet
1545 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1546 _exception_pc = 0;
1547 _exception_handler_pc = 0;
1548 _is_method_handle_return = 0;
1549 _jvmti_thread_state= NULL;
1550 _should_post_on_exceptions_flag = JNI_FALSE;
1551 _jvmti_get_loaded_classes_closure = NULL;
1552 _interp_only_mode = 0;
1553 _special_runtime_exit_condition = _no_async_condition;
1554 _pending_async_exception = NULL;
1555 _thread_stat = NULL;
1556 _thread_stat = new ThreadStatistics();
1557 _blocked_on_compilation = false;
1558 _jni_active_critical = 0;
1559 _pending_jni_exception_check_fn = NULL;
1560 _do_not_unlock_if_synchronized = false;
1561 _cached_monitor_info = NULL;
1562 _parker = Parker::Allocate(this);
1563
1564 #ifndef PRODUCT
1565 _jmp_ring_index = 0;
1566 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1567 record_jump(NULL, NULL, NULL, 0);
1568 }
1569 #endif // PRODUCT
1570
1571 // Setup safepoint state info for this thread
1572 ThreadSafepointState::create(this);
1573
1574 debug_only(_java_call_counter = 0);
1575
1576 // JVMTI PopFrame support
1577 _popframe_condition = popframe_inactive;
1578 _popframe_preserved_args = NULL;
1579 _popframe_preserved_args_size = 0;
1580 _frames_to_pop_failed_realloc = 0;
1581
1582 if (SafepointMechanism::uses_thread_local_poll()) {
1583 SafepointMechanism::initialize_header(this);
1584 }
1585
1586 pd_initialize();
1587 }
1588
1589 #if INCLUDE_ALL_GCS
1590 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1591 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1592 #endif // INCLUDE_ALL_GCS
1593
1594 JavaThread::JavaThread(bool is_attaching_via_jni) :
1595 Thread()
1596 #if INCLUDE_ALL_GCS
1597 , _satb_mark_queue(&_satb_mark_queue_set),
1598 _dirty_card_queue(&_dirty_card_queue_set)
1599 #endif // INCLUDE_ALL_GCS
1600 {
1601 initialize();
1602 if (is_attaching_via_jni) {
1603 _jni_attach_state = _attaching_via_jni;
1604 } else {
1605 _jni_attach_state = _not_attaching_via_jni;
1606 }
1607 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1608 }
1609
1610 bool JavaThread::reguard_stack(address cur_sp) {
1611 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1612 && _stack_guard_state != stack_guard_reserved_disabled) {
1613 return true; // Stack already guarded or guard pages not needed.
1614 }
1615
1616 if (register_stack_overflow()) {
1617 // For those architectures which have separate register and
1618 // memory stacks, we must check the register stack to see if
1619 // it has overflowed.
1620 return false;
1621 }
1622
1623 // Java code never executes within the yellow zone: the latter is only
1624 // there to provoke an exception during stack banging. If java code
1625 // is executing there, either StackShadowPages should be larger, or
1626 // some exception code in c1, c2 or the interpreter isn't unwinding
1627 // when it should.
1628 guarantee(cur_sp > stack_reserved_zone_base(),
1629 "not enough space to reguard - increase StackShadowPages");
1630 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1631 enable_stack_yellow_reserved_zone();
1632 if (reserved_stack_activation() != stack_base()) {
1633 set_reserved_stack_activation(stack_base());
1634 }
1635 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1636 set_reserved_stack_activation(stack_base());
1637 enable_stack_reserved_zone();
1638 }
1639 return true;
1640 }
1641
1642 bool JavaThread::reguard_stack(void) {
1643 return reguard_stack(os::current_stack_pointer());
1644 }
1645
1646
1647 void JavaThread::block_if_vm_exited() {
1648 if (_terminated == _vm_exited) {
1649 // _vm_exited is set at safepoint, and Threads_lock is never released
1650 // we will block here forever
1651 Threads_lock->lock_without_safepoint_check();
1652 ShouldNotReachHere();
1653 }
1654 }
1655
1656
1657 // Remove this ifdef when C1 is ported to the compiler interface.
1658 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1659 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1660
1661 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1662 Thread()
1663 #if INCLUDE_ALL_GCS
1664 , _satb_mark_queue(&_satb_mark_queue_set),
1665 _dirty_card_queue(&_dirty_card_queue_set)
1666 #endif // INCLUDE_ALL_GCS
1667 {
1668 initialize();
1669 _jni_attach_state = _not_attaching_via_jni;
1670 set_entry_point(entry_point);
1671 // Create the native thread itself.
1672 // %note runtime_23
1673 os::ThreadType thr_type = os::java_thread;
1674 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1675 os::java_thread;
1676 os::create_thread(this, thr_type, stack_sz);
1677 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1678 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1679 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1680 // the exception consists of creating the exception object & initializing it, initialization
1681 // will leave the VM via a JavaCall and then all locks must be unlocked).
1682 //
1683 // The thread is still suspended when we reach here. Thread must be explicit started
1684 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1685 // by calling Threads:add. The reason why this is not done here, is because the thread
1686 // object must be fully initialized (take a look at JVM_Start)
1687 }
1688
1689 JavaThread::~JavaThread() {
1690
1691 // JSR166 -- return the parker to the free list
1692 Parker::Release(_parker);
1693 _parker = NULL;
1694
1695 // Free any remaining previous UnrollBlock
1696 vframeArray* old_array = vframe_array_last();
1697
1698 if (old_array != NULL) {
1699 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1700 old_array->set_unroll_block(NULL);
1701 delete old_info;
1702 delete old_array;
1703 }
1704
1705 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1706 if (deferred != NULL) {
1707 // This can only happen if thread is destroyed before deoptimization occurs.
1708 assert(deferred->length() != 0, "empty array!");
1709 do {
1710 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1711 deferred->remove_at(0);
1712 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1713 delete dlv;
1714 } while (deferred->length() != 0);
1715 delete deferred;
1716 }
1717
1718 // All Java related clean up happens in exit
1719 ThreadSafepointState::destroy(this);
1720 if (_thread_stat != NULL) delete _thread_stat;
1721
1722 #if INCLUDE_JVMCI
1723 if (JVMCICounterSize > 0) {
1724 if (jvmci_counters_include(this)) {
1725 for (int i = 0; i < JVMCICounterSize; i++) {
1726 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1727 }
1728 }
1729 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1730 }
1731 #endif // INCLUDE_JVMCI
1732 }
1733
1734
1735 // The first routine called by a new Java thread
1736 void JavaThread::run() {
1737 // initialize thread-local alloc buffer related fields
1738 this->initialize_tlab();
1739
1740 // used to test validity of stack trace backs
1741 this->record_base_of_stack_pointer();
1742
1743 // Record real stack base and size.
1744 this->record_stack_base_and_size();
1745
1746 this->create_stack_guard_pages();
1747
1748 this->cache_global_variables();
1749
1750 // Thread is now sufficient initialized to be handled by the safepoint code as being
1751 // in the VM. Change thread state from _thread_new to _thread_in_vm
1752 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1753
1754 assert(JavaThread::current() == this, "sanity check");
1755 assert(!Thread::current()->owns_locks(), "sanity check");
1756
1757 DTRACE_THREAD_PROBE(start, this);
1758
1759 // This operation might block. We call that after all safepoint checks for a new thread has
1760 // been completed.
1761 this->set_active_handles(JNIHandleBlock::allocate_block());
1762
1763 if (JvmtiExport::should_post_thread_life()) {
1764 JvmtiExport::post_thread_start(this);
1765 }
1766
1767 EventThreadStart event;
1768 if (event.should_commit()) {
1769 event.set_thread(THREAD_TRACE_ID(this));
1770 event.commit();
1771 }
1772
1773 // We call another function to do the rest so we are sure that the stack addresses used
1774 // from there will be lower than the stack base just computed
1775 thread_main_inner();
1776
1777 // Note, thread is no longer valid at this point!
1778 }
1779
1780
1781 void JavaThread::thread_main_inner() {
1782 assert(JavaThread::current() == this, "sanity check");
1783 assert(this->threadObj() != NULL, "just checking");
1784
1785 // Execute thread entry point unless this thread has a pending exception
1786 // or has been stopped before starting.
1787 // Note: Due to JVM_StopThread we can have pending exceptions already!
1788 if (!this->has_pending_exception() &&
1789 !java_lang_Thread::is_stillborn(this->threadObj())) {
1790 {
1791 ResourceMark rm(this);
1792 this->set_native_thread_name(this->get_thread_name());
1793 }
1794 HandleMark hm(this);
1795 this->entry_point()(this, this);
1796 }
1797
1798 DTRACE_THREAD_PROBE(stop, this);
1799
1800 this->exit(false);
1801 this->smr_delete();
1802 }
1803
1804
1805 static void ensure_join(JavaThread* thread) {
1806 // We do not need to grab the Threads_lock, since we are operating on ourself.
1807 Handle threadObj(thread, thread->threadObj());
1808 assert(threadObj.not_null(), "java thread object must exist");
1809 ObjectLocker lock(threadObj, thread);
1810 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1811 thread->clear_pending_exception();
1812 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1813 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1814 // Clear the native thread instance - this makes isAlive return false and allows the join()
1815 // to complete once we've done the notify_all below
1816 java_lang_Thread::set_thread(threadObj(), NULL);
1817 lock.notify_all(thread);
1818 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1819 thread->clear_pending_exception();
1820 }
1821
1822
1823 // For any new cleanup additions, please check to see if they need to be applied to
1824 // cleanup_failed_attach_current_thread as well.
1825 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1826 assert(this == JavaThread::current(), "thread consistency check");
1827
1828 elapsedTimer _timer_exit_phase1;
1829 elapsedTimer _timer_exit_phase2;
1830 elapsedTimer _timer_exit_phase3;
1831 elapsedTimer _timer_exit_phase4;
1832
1833 if (log_is_enabled(Debug, os, thread, timer)) {
1834 _timer_exit_phase1.start();
1835 }
1836
1837 HandleMark hm(this);
1838 Handle uncaught_exception(this, this->pending_exception());
1839 this->clear_pending_exception();
1840 Handle threadObj(this, this->threadObj());
1841 assert(threadObj.not_null(), "Java thread object should be created");
1842
1843 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1844 {
1845 EXCEPTION_MARK;
1846
1847 CLEAR_PENDING_EXCEPTION;
1848 }
1849 if (!destroy_vm) {
1850 if (uncaught_exception.not_null()) {
1851 EXCEPTION_MARK;
1852 // Call method Thread.dispatchUncaughtException().
1853 Klass* thread_klass = SystemDictionary::Thread_klass();
1854 JavaValue result(T_VOID);
1855 JavaCalls::call_virtual(&result,
1856 threadObj, thread_klass,
1857 vmSymbols::dispatchUncaughtException_name(),
1858 vmSymbols::throwable_void_signature(),
1859 uncaught_exception,
1860 THREAD);
1861 if (HAS_PENDING_EXCEPTION) {
1862 ResourceMark rm(this);
1863 jio_fprintf(defaultStream::error_stream(),
1864 "\nException: %s thrown from the UncaughtExceptionHandler"
1865 " in thread \"%s\"\n",
1866 pending_exception()->klass()->external_name(),
1867 get_thread_name());
1868 CLEAR_PENDING_EXCEPTION;
1869 }
1870 }
1871
1872 // Called before the java thread exit since we want to read info
1873 // from java_lang_Thread object
1874 EventThreadEnd event;
1875 if (event.should_commit()) {
1876 event.set_thread(THREAD_TRACE_ID(this));
1877 event.commit();
1878 }
1879
1880 // Call after last event on thread
1881 EVENT_THREAD_EXIT(this);
1882
1883 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1884 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1885 // is deprecated anyhow.
1886 if (!is_Compiler_thread()) {
1887 int count = 3;
1888 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1889 EXCEPTION_MARK;
1890 JavaValue result(T_VOID);
1891 Klass* thread_klass = SystemDictionary::Thread_klass();
1892 JavaCalls::call_virtual(&result,
1893 threadObj, thread_klass,
1894 vmSymbols::exit_method_name(),
1895 vmSymbols::void_method_signature(),
1896 THREAD);
1897 CLEAR_PENDING_EXCEPTION;
1898 }
1899 }
1900 // notify JVMTI
1901 if (JvmtiExport::should_post_thread_life()) {
1902 JvmtiExport::post_thread_end(this);
1903 }
1904
1905 // We have notified the agents that we are exiting, before we go on,
1906 // we must check for a pending external suspend request and honor it
1907 // in order to not surprise the thread that made the suspend request.
1908 while (true) {
1909 {
1910 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1911 if (!is_external_suspend()) {
1912 set_terminated(_thread_exiting);
1913 ThreadService::current_thread_exiting(this);
1914 break;
1915 }
1916 // Implied else:
1917 // Things get a little tricky here. We have a pending external
1918 // suspend request, but we are holding the SR_lock so we
1919 // can't just self-suspend. So we temporarily drop the lock
1920 // and then self-suspend.
1921 }
1922
1923 ThreadBlockInVM tbivm(this);
1924 java_suspend_self();
1925
1926 // We're done with this suspend request, but we have to loop around
1927 // and check again. Eventually we will get SR_lock without a pending
1928 // external suspend request and will be able to mark ourselves as
1929 // exiting.
1930 }
1931 // no more external suspends are allowed at this point
1932 } else {
1933 // before_exit() has already posted JVMTI THREAD_END events
1934 }
1935
1936 if (log_is_enabled(Debug, os, thread, timer)) {
1937 _timer_exit_phase1.stop();
1938 _timer_exit_phase2.start();
1939 }
1940 // Notify waiters on thread object. This has to be done after exit() is called
1941 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1942 // group should have the destroyed bit set before waiters are notified).
1943 ensure_join(this);
1944 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1945
1946 if (log_is_enabled(Debug, os, thread, timer)) {
1947 _timer_exit_phase2.stop();
1948 _timer_exit_phase3.start();
1949 }
1950 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1951 // held by this thread must be released. The spec does not distinguish
1952 // between JNI-acquired and regular Java monitors. We can only see
1953 // regular Java monitors here if monitor enter-exit matching is broken.
1954 //
1955 // Optionally release any monitors for regular JavaThread exits. This
1956 // is provided as a work around for any bugs in monitor enter-exit
1957 // matching. This can be expensive so it is not enabled by default.
1958 //
1959 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1960 // ObjectSynchronizer::release_monitors_owned_by_thread().
1961 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
1962 // Sanity check even though JNI DetachCurrentThread() would have
1963 // returned JNI_ERR if there was a Java frame. JavaThread exit
1964 // should be done executing Java code by the time we get here.
1965 assert(!this->has_last_Java_frame(),
1966 "should not have a Java frame when detaching or exiting");
1967 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1968 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1969 }
1970
1971 // These things needs to be done while we are still a Java Thread. Make sure that thread
1972 // is in a consistent state, in case GC happens
1973 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1974
1975 if (active_handles() != NULL) {
1976 JNIHandleBlock* block = active_handles();
1977 set_active_handles(NULL);
1978 JNIHandleBlock::release_block(block);
1979 }
1980
1981 if (free_handle_block() != NULL) {
1982 JNIHandleBlock* block = free_handle_block();
1983 set_free_handle_block(NULL);
1984 JNIHandleBlock::release_block(block);
1985 }
1986
1987 // These have to be removed while this is still a valid thread.
1988 remove_stack_guard_pages();
1989
1990 if (UseTLAB) {
1991 tlab().make_parsable(true); // retire TLAB
1992 }
1993
1994 if (JvmtiEnv::environments_might_exist()) {
1995 JvmtiExport::cleanup_thread(this);
1996 }
1997
1998 // We must flush any deferred card marks before removing a thread from
1999 // the list of active threads.
2000 Universe::heap()->flush_deferred_store_barrier(this);
2001 assert(deferred_card_mark().is_empty(), "Should have been flushed");
2002
2003 #if INCLUDE_ALL_GCS
2004 // We must flush the G1-related buffers before removing a thread
2005 // from the list of active threads. We must do this after any deferred
2006 // card marks have been flushed (above) so that any entries that are
2007 // added to the thread's dirty card queue as a result are not lost.
2008 if (UseG1GC) {
2009 flush_barrier_queues();
2010 }
2011 #endif // INCLUDE_ALL_GCS
2012
2013 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2014 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2015 os::current_thread_id());
2016
2017 if (log_is_enabled(Debug, os, thread, timer)) {
2018 _timer_exit_phase3.stop();
2019 _timer_exit_phase4.start();
2020 }
2021 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2022 Threads::remove(this);
2023
2024 if (log_is_enabled(Debug, os, thread, timer)) {
2025 _timer_exit_phase4.stop();
2026 ResourceMark rm(this);
2027 log_debug(os, thread, timer)("name='%s'"
2028 ", exit-phase1=" JLONG_FORMAT
2029 ", exit-phase2=" JLONG_FORMAT
2030 ", exit-phase3=" JLONG_FORMAT
2031 ", exit-phase4=" JLONG_FORMAT,
2032 get_thread_name(),
2033 _timer_exit_phase1.milliseconds(),
2034 _timer_exit_phase2.milliseconds(),
2035 _timer_exit_phase3.milliseconds(),
2036 _timer_exit_phase4.milliseconds());
2037 }
2038 }
2039
2040 #if INCLUDE_ALL_GCS
2041 // Flush G1-related queues.
2042 void JavaThread::flush_barrier_queues() {
2043 satb_mark_queue().flush();
2044 dirty_card_queue().flush();
2045 }
2046
2047 void JavaThread::initialize_queues() {
2048 assert(!SafepointSynchronize::is_at_safepoint(),
2049 "we should not be at a safepoint");
2050
2051 SATBMarkQueue& satb_queue = satb_mark_queue();
2052 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
2053 // The SATB queue should have been constructed with its active
2054 // field set to false.
2055 assert(!satb_queue.is_active(), "SATB queue should not be active");
2056 assert(satb_queue.is_empty(), "SATB queue should be empty");
2057 // If we are creating the thread during a marking cycle, we should
2058 // set the active field of the SATB queue to true.
2059 if (satb_queue_set.is_active()) {
2060 satb_queue.set_active(true);
2061 }
2062
2063 DirtyCardQueue& dirty_queue = dirty_card_queue();
2064 // The dirty card queue should have been constructed with its
2065 // active field set to true.
2066 assert(dirty_queue.is_active(), "dirty card queue should be active");
2067 }
2068 #endif // INCLUDE_ALL_GCS
2069
2070 void JavaThread::cleanup_failed_attach_current_thread() {
2071 if (active_handles() != NULL) {
2072 JNIHandleBlock* block = active_handles();
2073 set_active_handles(NULL);
2074 JNIHandleBlock::release_block(block);
2075 }
2076
2077 if (free_handle_block() != NULL) {
2078 JNIHandleBlock* block = free_handle_block();
2079 set_free_handle_block(NULL);
2080 JNIHandleBlock::release_block(block);
2081 }
2082
2083 // These have to be removed while this is still a valid thread.
2084 remove_stack_guard_pages();
2085
2086 if (UseTLAB) {
2087 tlab().make_parsable(true); // retire TLAB, if any
2088 }
2089
2090 #if INCLUDE_ALL_GCS
2091 if (UseG1GC) {
2092 flush_barrier_queues();
2093 }
2094 #endif // INCLUDE_ALL_GCS
2095
2096 Threads::remove(this);
2097 this->smr_delete();
2098 }
2099
2100
2101
2102
2103 JavaThread* JavaThread::active() {
2104 Thread* thread = Thread::current();
2105 if (thread->is_Java_thread()) {
2106 return (JavaThread*) thread;
2107 } else {
2108 assert(thread->is_VM_thread(), "this must be a vm thread");
2109 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2110 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2111 assert(ret->is_Java_thread(), "must be a Java thread");
2112 return ret;
2113 }
2114 }
2115
2116 bool JavaThread::is_lock_owned(address adr) const {
2117 if (Thread::is_lock_owned(adr)) return true;
2118
2119 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2120 if (chunk->contains(adr)) return true;
2121 }
2122
2123 return false;
2124 }
2125
2126
2127 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2128 chunk->set_next(monitor_chunks());
2129 set_monitor_chunks(chunk);
2130 }
2131
2132 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2133 guarantee(monitor_chunks() != NULL, "must be non empty");
2134 if (monitor_chunks() == chunk) {
2135 set_monitor_chunks(chunk->next());
2136 } else {
2137 MonitorChunk* prev = monitor_chunks();
2138 while (prev->next() != chunk) prev = prev->next();
2139 prev->set_next(chunk->next());
2140 }
2141 }
2142
2143 // JVM support.
2144
2145 // Note: this function shouldn't block if it's called in
2146 // _thread_in_native_trans state (such as from
2147 // check_special_condition_for_native_trans()).
2148 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2149
2150 if (has_last_Java_frame() && has_async_condition()) {
2151 // If we are at a polling page safepoint (not a poll return)
2152 // then we must defer async exception because live registers
2153 // will be clobbered by the exception path. Poll return is
2154 // ok because the call we a returning from already collides
2155 // with exception handling registers and so there is no issue.
2156 // (The exception handling path kills call result registers but
2157 // this is ok since the exception kills the result anyway).
2158
2159 if (is_at_poll_safepoint()) {
2160 // if the code we are returning to has deoptimized we must defer
2161 // the exception otherwise live registers get clobbered on the
2162 // exception path before deoptimization is able to retrieve them.
2163 //
2164 RegisterMap map(this, false);
2165 frame caller_fr = last_frame().sender(&map);
2166 assert(caller_fr.is_compiled_frame(), "what?");
2167 if (caller_fr.is_deoptimized_frame()) {
2168 log_info(exceptions)("deferred async exception at compiled safepoint");
2169 return;
2170 }
2171 }
2172 }
2173
2174 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2175 if (condition == _no_async_condition) {
2176 // Conditions have changed since has_special_runtime_exit_condition()
2177 // was called:
2178 // - if we were here only because of an external suspend request,
2179 // then that was taken care of above (or cancelled) so we are done
2180 // - if we were here because of another async request, then it has
2181 // been cleared between the has_special_runtime_exit_condition()
2182 // and now so again we are done
2183 return;
2184 }
2185
2186 // Check for pending async. exception
2187 if (_pending_async_exception != NULL) {
2188 // Only overwrite an already pending exception, if it is not a threadDeath.
2189 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2190
2191 // We cannot call Exceptions::_throw(...) here because we cannot block
2192 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2193
2194 LogTarget(Info, exceptions) lt;
2195 if (lt.is_enabled()) {
2196 ResourceMark rm;
2197 LogStream ls(lt);
2198 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2199 if (has_last_Java_frame()) {
2200 frame f = last_frame();
2201 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2202 }
2203 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2204 }
2205 _pending_async_exception = NULL;
2206 clear_has_async_exception();
2207 }
2208 }
2209
2210 if (check_unsafe_error &&
2211 condition == _async_unsafe_access_error && !has_pending_exception()) {
2212 condition = _no_async_condition; // done
2213 switch (thread_state()) {
2214 case _thread_in_vm: {
2215 JavaThread* THREAD = this;
2216 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2217 }
2218 case _thread_in_native: {
2219 ThreadInVMfromNative tiv(this);
2220 JavaThread* THREAD = this;
2221 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2222 }
2223 case _thread_in_Java: {
2224 ThreadInVMfromJava tiv(this);
2225 JavaThread* THREAD = this;
2226 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2227 }
2228 default:
2229 ShouldNotReachHere();
2230 }
2231 }
2232
2233 assert(condition == _no_async_condition || has_pending_exception() ||
2234 (!check_unsafe_error && condition == _async_unsafe_access_error),
2235 "must have handled the async condition, if no exception");
2236 }
2237
2238 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2239 //
2240 // Check for pending external suspend. Internal suspend requests do
2241 // not use handle_special_runtime_exit_condition().
2242 // If JNIEnv proxies are allowed, don't self-suspend if the target
2243 // thread is not the current thread. In older versions of jdbx, jdbx
2244 // threads could call into the VM with another thread's JNIEnv so we
2245 // can be here operating on behalf of a suspended thread (4432884).
2246 bool do_self_suspend = is_external_suspend_with_lock();
2247 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2248 //
2249 // Because thread is external suspended the safepoint code will count
2250 // thread as at a safepoint. This can be odd because we can be here
2251 // as _thread_in_Java which would normally transition to _thread_blocked
2252 // at a safepoint. We would like to mark the thread as _thread_blocked
2253 // before calling java_suspend_self like all other callers of it but
2254 // we must then observe proper safepoint protocol. (We can't leave
2255 // _thread_blocked with a safepoint in progress). However we can be
2256 // here as _thread_in_native_trans so we can't use a normal transition
2257 // constructor/destructor pair because they assert on that type of
2258 // transition. We could do something like:
2259 //
2260 // JavaThreadState state = thread_state();
2261 // set_thread_state(_thread_in_vm);
2262 // {
2263 // ThreadBlockInVM tbivm(this);
2264 // java_suspend_self()
2265 // }
2266 // set_thread_state(_thread_in_vm_trans);
2267 // if (safepoint) block;
2268 // set_thread_state(state);
2269 //
2270 // but that is pretty messy. Instead we just go with the way the
2271 // code has worked before and note that this is the only path to
2272 // java_suspend_self that doesn't put the thread in _thread_blocked
2273 // mode.
2274
2275 frame_anchor()->make_walkable(this);
2276 java_suspend_self();
2277
2278 // We might be here for reasons in addition to the self-suspend request
2279 // so check for other async requests.
2280 }
2281
2282 if (check_asyncs) {
2283 check_and_handle_async_exceptions();
2284 }
2285 #if INCLUDE_TRACE
2286 if (is_trace_suspend()) {
2287 TRACE_SUSPEND_THREAD(this);
2288 }
2289 #endif
2290 }
2291
2292 void JavaThread::send_thread_stop(oop java_throwable) {
2293 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2294 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2295 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2296
2297 // Do not throw asynchronous exceptions against the compiler thread
2298 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2299 if (!can_call_java()) return;
2300
2301 {
2302 // Actually throw the Throwable against the target Thread - however
2303 // only if there is no thread death exception installed already.
2304 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2305 // If the topmost frame is a runtime stub, then we are calling into
2306 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2307 // must deoptimize the caller before continuing, as the compiled exception handler table
2308 // may not be valid
2309 if (has_last_Java_frame()) {
2310 frame f = last_frame();
2311 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2312 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2313 RegisterMap reg_map(this, UseBiasedLocking);
2314 frame compiled_frame = f.sender(®_map);
2315 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2316 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2317 }
2318 }
2319 }
2320
2321 // Set async. pending exception in thread.
2322 set_pending_async_exception(java_throwable);
2323
2324 if (log_is_enabled(Info, exceptions)) {
2325 ResourceMark rm;
2326 log_info(exceptions)("Pending Async. exception installed of type: %s",
2327 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2328 }
2329 // for AbortVMOnException flag
2330 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2331 }
2332 }
2333
2334
2335 // Interrupt thread so it will wake up from a potential wait()
2336 Thread::interrupt(this);
2337 }
2338
2339 // External suspension mechanism.
2340 //
2341 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2342 // to any VM_locks and it is at a transition
2343 // Self-suspension will happen on the transition out of the vm.
2344 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2345 //
2346 // Guarantees on return:
2347 // + Target thread will not execute any new bytecode (that's why we need to
2348 // force a safepoint)
2349 // + Target thread will not enter any new monitors
2350 //
2351 void JavaThread::java_suspend() {
2352 ThreadsListHandle tlh;
2353 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2354 return;
2355 }
2356
2357 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2358 if (!is_external_suspend()) {
2359 // a racing resume has cancelled us; bail out now
2360 return;
2361 }
2362
2363 // suspend is done
2364 uint32_t debug_bits = 0;
2365 // Warning: is_ext_suspend_completed() may temporarily drop the
2366 // SR_lock to allow the thread to reach a stable thread state if
2367 // it is currently in a transient thread state.
2368 if (is_ext_suspend_completed(false /* !called_by_wait */,
2369 SuspendRetryDelay, &debug_bits)) {
2370 return;
2371 }
2372 }
2373
2374 VM_ThreadSuspend vm_suspend;
2375 VMThread::execute(&vm_suspend);
2376 }
2377
2378 // Part II of external suspension.
2379 // A JavaThread self suspends when it detects a pending external suspend
2380 // request. This is usually on transitions. It is also done in places
2381 // where continuing to the next transition would surprise the caller,
2382 // e.g., monitor entry.
2383 //
2384 // Returns the number of times that the thread self-suspended.
2385 //
2386 // Note: DO NOT call java_suspend_self() when you just want to block current
2387 // thread. java_suspend_self() is the second stage of cooperative
2388 // suspension for external suspend requests and should only be used
2389 // to complete an external suspend request.
2390 //
2391 int JavaThread::java_suspend_self() {
2392 int ret = 0;
2393
2394 // we are in the process of exiting so don't suspend
2395 if (is_exiting()) {
2396 clear_external_suspend();
2397 return ret;
2398 }
2399
2400 assert(_anchor.walkable() ||
2401 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2402 "must have walkable stack");
2403
2404 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2405
2406 assert(!this->is_ext_suspended(),
2407 "a thread trying to self-suspend should not already be suspended");
2408
2409 if (this->is_suspend_equivalent()) {
2410 // If we are self-suspending as a result of the lifting of a
2411 // suspend equivalent condition, then the suspend_equivalent
2412 // flag is not cleared until we set the ext_suspended flag so
2413 // that wait_for_ext_suspend_completion() returns consistent
2414 // results.
2415 this->clear_suspend_equivalent();
2416 }
2417
2418 // A racing resume may have cancelled us before we grabbed SR_lock
2419 // above. Or another external suspend request could be waiting for us
2420 // by the time we return from SR_lock()->wait(). The thread
2421 // that requested the suspension may already be trying to walk our
2422 // stack and if we return now, we can change the stack out from under
2423 // it. This would be a "bad thing (TM)" and cause the stack walker
2424 // to crash. We stay self-suspended until there are no more pending
2425 // external suspend requests.
2426 while (is_external_suspend()) {
2427 ret++;
2428 this->set_ext_suspended();
2429
2430 // _ext_suspended flag is cleared by java_resume()
2431 while (is_ext_suspended()) {
2432 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2433 }
2434 }
2435
2436 return ret;
2437 }
2438
2439 #ifdef ASSERT
2440 // verify the JavaThread has not yet been published in the Threads::list, and
2441 // hence doesn't need protection from concurrent access at this stage
2442 void JavaThread::verify_not_published() {
2443 ThreadsListHandle tlh;
2444 assert(!tlh.includes(this), "JavaThread shouldn't have been published yet!");
2445 }
2446 #endif
2447
2448 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2449 // progress or when _suspend_flags is non-zero.
2450 // Current thread needs to self-suspend if there is a suspend request and/or
2451 // block if a safepoint is in progress.
2452 // Async exception ISN'T checked.
2453 // Note only the ThreadInVMfromNative transition can call this function
2454 // directly and when thread state is _thread_in_native_trans
2455 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2456 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2457
2458 JavaThread *curJT = JavaThread::current();
2459 bool do_self_suspend = thread->is_external_suspend();
2460
2461 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2462
2463 // If JNIEnv proxies are allowed, don't self-suspend if the target
2464 // thread is not the current thread. In older versions of jdbx, jdbx
2465 // threads could call into the VM with another thread's JNIEnv so we
2466 // can be here operating on behalf of a suspended thread (4432884).
2467 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2468 JavaThreadState state = thread->thread_state();
2469
2470 // We mark this thread_blocked state as a suspend-equivalent so
2471 // that a caller to is_ext_suspend_completed() won't be confused.
2472 // The suspend-equivalent state is cleared by java_suspend_self().
2473 thread->set_suspend_equivalent();
2474
2475 // If the safepoint code sees the _thread_in_native_trans state, it will
2476 // wait until the thread changes to other thread state. There is no
2477 // guarantee on how soon we can obtain the SR_lock and complete the
2478 // self-suspend request. It would be a bad idea to let safepoint wait for
2479 // too long. Temporarily change the state to _thread_blocked to
2480 // let the VM thread know that this thread is ready for GC. The problem
2481 // of changing thread state is that safepoint could happen just after
2482 // java_suspend_self() returns after being resumed, and VM thread will
2483 // see the _thread_blocked state. We must check for safepoint
2484 // after restoring the state and make sure we won't leave while a safepoint
2485 // is in progress.
2486 thread->set_thread_state(_thread_blocked);
2487 thread->java_suspend_self();
2488 thread->set_thread_state(state);
2489
2490 InterfaceSupport::serialize_thread_state_with_handler(thread);
2491 }
2492
2493 SafepointMechanism::block_if_requested(curJT);
2494
2495 if (thread->is_deopt_suspend()) {
2496 thread->clear_deopt_suspend();
2497 RegisterMap map(thread, false);
2498 frame f = thread->last_frame();
2499 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2500 f = f.sender(&map);
2501 }
2502 if (f.id() == thread->must_deopt_id()) {
2503 thread->clear_must_deopt_id();
2504 f.deoptimize(thread);
2505 } else {
2506 fatal("missed deoptimization!");
2507 }
2508 }
2509 #if INCLUDE_TRACE
2510 if (thread->is_trace_suspend()) {
2511 TRACE_SUSPEND_THREAD(thread);
2512 }
2513 #endif
2514 }
2515
2516 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2517 // progress or when _suspend_flags is non-zero.
2518 // Current thread needs to self-suspend if there is a suspend request and/or
2519 // block if a safepoint is in progress.
2520 // Also check for pending async exception (not including unsafe access error).
2521 // Note only the native==>VM/Java barriers can call this function and when
2522 // thread state is _thread_in_native_trans.
2523 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2524 check_safepoint_and_suspend_for_native_trans(thread);
2525
2526 if (thread->has_async_exception()) {
2527 // We are in _thread_in_native_trans state, don't handle unsafe
2528 // access error since that may block.
2529 thread->check_and_handle_async_exceptions(false);
2530 }
2531 }
2532
2533 // This is a variant of the normal
2534 // check_special_condition_for_native_trans with slightly different
2535 // semantics for use by critical native wrappers. It does all the
2536 // normal checks but also performs the transition back into
2537 // thread_in_Java state. This is required so that critical natives
2538 // can potentially block and perform a GC if they are the last thread
2539 // exiting the GCLocker.
2540 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2541 check_special_condition_for_native_trans(thread);
2542
2543 // Finish the transition
2544 thread->set_thread_state(_thread_in_Java);
2545
2546 if (thread->do_critical_native_unlock()) {
2547 ThreadInVMfromJavaNoAsyncException tiv(thread);
2548 GCLocker::unlock_critical(thread);
2549 thread->clear_critical_native_unlock();
2550 }
2551 }
2552
2553 // We need to guarantee the Threads_lock here, since resumes are not
2554 // allowed during safepoint synchronization
2555 // Can only resume from an external suspension
2556 void JavaThread::java_resume() {
2557 assert_locked_or_safepoint(Threads_lock);
2558
2559 // Sanity check: thread is gone, has started exiting or the thread
2560 // was not externally suspended.
2561 ThreadsListHandle tlh;
2562 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2563 return;
2564 }
2565
2566 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2567
2568 clear_external_suspend();
2569
2570 if (is_ext_suspended()) {
2571 clear_ext_suspended();
2572 SR_lock()->notify_all();
2573 }
2574 }
2575
2576 size_t JavaThread::_stack_red_zone_size = 0;
2577 size_t JavaThread::_stack_yellow_zone_size = 0;
2578 size_t JavaThread::_stack_reserved_zone_size = 0;
2579 size_t JavaThread::_stack_shadow_zone_size = 0;
2580
2581 void JavaThread::create_stack_guard_pages() {
2582 if (!os::uses_stack_guard_pages() ||
2583 _stack_guard_state != stack_guard_unused ||
2584 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2585 log_info(os, thread)("Stack guard page creation for thread "
2586 UINTX_FORMAT " disabled", os::current_thread_id());
2587 return;
2588 }
2589 address low_addr = stack_end();
2590 size_t len = stack_guard_zone_size();
2591
2592 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2593 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2594
2595 int must_commit = os::must_commit_stack_guard_pages();
2596 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2597
2598 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2599 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2600 return;
2601 }
2602
2603 if (os::guard_memory((char *) low_addr, len)) {
2604 _stack_guard_state = stack_guard_enabled;
2605 } else {
2606 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2607 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2608 if (os::uncommit_memory((char *) low_addr, len)) {
2609 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2610 }
2611 return;
2612 }
2613
2614 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2615 PTR_FORMAT "-" PTR_FORMAT ".",
2616 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2617 }
2618
2619 void JavaThread::remove_stack_guard_pages() {
2620 assert(Thread::current() == this, "from different thread");
2621 if (_stack_guard_state == stack_guard_unused) return;
2622 address low_addr = stack_end();
2623 size_t len = stack_guard_zone_size();
2624
2625 if (os::must_commit_stack_guard_pages()) {
2626 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2627 _stack_guard_state = stack_guard_unused;
2628 } else {
2629 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2630 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2631 return;
2632 }
2633 } else {
2634 if (_stack_guard_state == stack_guard_unused) return;
2635 if (os::unguard_memory((char *) low_addr, len)) {
2636 _stack_guard_state = stack_guard_unused;
2637 } else {
2638 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2639 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2640 return;
2641 }
2642 }
2643
2644 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2645 PTR_FORMAT "-" PTR_FORMAT ".",
2646 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2647 }
2648
2649 void JavaThread::enable_stack_reserved_zone() {
2650 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2651 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2652
2653 // The base notation is from the stack's point of view, growing downward.
2654 // We need to adjust it to work correctly with guard_memory()
2655 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2656
2657 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2658 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2659
2660 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2661 _stack_guard_state = stack_guard_enabled;
2662 } else {
2663 warning("Attempt to guard stack reserved zone failed.");
2664 }
2665 enable_register_stack_guard();
2666 }
2667
2668 void JavaThread::disable_stack_reserved_zone() {
2669 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2670 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled");
2671
2672 // Simply return if called for a thread that does not use guard pages.
2673 if (_stack_guard_state == stack_guard_unused) return;
2674
2675 // The base notation is from the stack's point of view, growing downward.
2676 // We need to adjust it to work correctly with guard_memory()
2677 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2678
2679 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2680 _stack_guard_state = stack_guard_reserved_disabled;
2681 } else {
2682 warning("Attempt to unguard stack reserved zone failed.");
2683 }
2684 disable_register_stack_guard();
2685 }
2686
2687 void JavaThread::enable_stack_yellow_reserved_zone() {
2688 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2689 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2690
2691 // The base notation is from the stacks point of view, growing downward.
2692 // We need to adjust it to work correctly with guard_memory()
2693 address base = stack_red_zone_base();
2694
2695 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2696 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2697
2698 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2699 _stack_guard_state = stack_guard_enabled;
2700 } else {
2701 warning("Attempt to guard stack yellow zone failed.");
2702 }
2703 enable_register_stack_guard();
2704 }
2705
2706 void JavaThread::disable_stack_yellow_reserved_zone() {
2707 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2708 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2709
2710 // Simply return if called for a thread that does not use guard pages.
2711 if (_stack_guard_state == stack_guard_unused) return;
2712
2713 // The base notation is from the stacks point of view, growing downward.
2714 // We need to adjust it to work correctly with guard_memory()
2715 address base = stack_red_zone_base();
2716
2717 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2718 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2719 } else {
2720 warning("Attempt to unguard stack yellow zone failed.");
2721 }
2722 disable_register_stack_guard();
2723 }
2724
2725 void JavaThread::enable_stack_red_zone() {
2726 // The base notation is from the stacks point of view, growing downward.
2727 // We need to adjust it to work correctly with guard_memory()
2728 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2729 address base = stack_red_zone_base() - stack_red_zone_size();
2730
2731 guarantee(base < stack_base(), "Error calculating stack red zone");
2732 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2733
2734 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2735 warning("Attempt to guard stack red zone failed.");
2736 }
2737 }
2738
2739 void JavaThread::disable_stack_red_zone() {
2740 // The base notation is from the stacks point of view, growing downward.
2741 // We need to adjust it to work correctly with guard_memory()
2742 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2743 address base = stack_red_zone_base() - stack_red_zone_size();
2744 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2745 warning("Attempt to unguard stack red zone failed.");
2746 }
2747 }
2748
2749 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2750 // ignore is there is no stack
2751 if (!has_last_Java_frame()) return;
2752 // traverse the stack frames. Starts from top frame.
2753 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2754 frame* fr = fst.current();
2755 f(fr, fst.register_map());
2756 }
2757 }
2758
2759
2760 #ifndef PRODUCT
2761 // Deoptimization
2762 // Function for testing deoptimization
2763 void JavaThread::deoptimize() {
2764 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2765 StackFrameStream fst(this, UseBiasedLocking);
2766 bool deopt = false; // Dump stack only if a deopt actually happens.
2767 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2768 // Iterate over all frames in the thread and deoptimize
2769 for (; !fst.is_done(); fst.next()) {
2770 if (fst.current()->can_be_deoptimized()) {
2771
2772 if (only_at) {
2773 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2774 // consists of comma or carriage return separated numbers so
2775 // search for the current bci in that string.
2776 address pc = fst.current()->pc();
2777 nmethod* nm = (nmethod*) fst.current()->cb();
2778 ScopeDesc* sd = nm->scope_desc_at(pc);
2779 char buffer[8];
2780 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2781 size_t len = strlen(buffer);
2782 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2783 while (found != NULL) {
2784 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2785 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2786 // Check that the bci found is bracketed by terminators.
2787 break;
2788 }
2789 found = strstr(found + 1, buffer);
2790 }
2791 if (!found) {
2792 continue;
2793 }
2794 }
2795
2796 if (DebugDeoptimization && !deopt) {
2797 deopt = true; // One-time only print before deopt
2798 tty->print_cr("[BEFORE Deoptimization]");
2799 trace_frames();
2800 trace_stack();
2801 }
2802 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2803 }
2804 }
2805
2806 if (DebugDeoptimization && deopt) {
2807 tty->print_cr("[AFTER Deoptimization]");
2808 trace_frames();
2809 }
2810 }
2811
2812
2813 // Make zombies
2814 void JavaThread::make_zombies() {
2815 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2816 if (fst.current()->can_be_deoptimized()) {
2817 // it is a Java nmethod
2818 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2819 nm->make_not_entrant();
2820 }
2821 }
2822 }
2823 #endif // PRODUCT
2824
2825
2826 void JavaThread::deoptimized_wrt_marked_nmethods() {
2827 if (!has_last_Java_frame()) return;
2828 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2829 StackFrameStream fst(this, UseBiasedLocking);
2830 for (; !fst.is_done(); fst.next()) {
2831 if (fst.current()->should_be_deoptimized()) {
2832 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2833 }
2834 }
2835 }
2836
2837
2838 // If the caller is a NamedThread, then remember, in the current scope,
2839 // the given JavaThread in its _processed_thread field.
2840 class RememberProcessedThread: public StackObj {
2841 NamedThread* _cur_thr;
2842 public:
2843 RememberProcessedThread(JavaThread* jthr) {
2844 Thread* thread = Thread::current();
2845 if (thread->is_Named_thread()) {
2846 _cur_thr = (NamedThread *)thread;
2847 _cur_thr->set_processed_thread(jthr);
2848 } else {
2849 _cur_thr = NULL;
2850 }
2851 }
2852
2853 ~RememberProcessedThread() {
2854 if (_cur_thr) {
2855 _cur_thr->set_processed_thread(NULL);
2856 }
2857 }
2858 };
2859
2860 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2861 // Verify that the deferred card marks have been flushed.
2862 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2863
2864 // Traverse the GCHandles
2865 Thread::oops_do(f, cf);
2866
2867 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2868
2869 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2870 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2871
2872 if (has_last_Java_frame()) {
2873 // Record JavaThread to GC thread
2874 RememberProcessedThread rpt(this);
2875
2876 // Traverse the privileged stack
2877 if (_privileged_stack_top != NULL) {
2878 _privileged_stack_top->oops_do(f);
2879 }
2880
2881 // traverse the registered growable array
2882 if (_array_for_gc != NULL) {
2883 for (int index = 0; index < _array_for_gc->length(); index++) {
2884 f->do_oop(_array_for_gc->adr_at(index));
2885 }
2886 }
2887
2888 // Traverse the monitor chunks
2889 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2890 chunk->oops_do(f);
2891 }
2892
2893 // Traverse the execution stack
2894 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2895 fst.current()->oops_do(f, cf, fst.register_map());
2896 }
2897 }
2898
2899 // callee_target is never live across a gc point so NULL it here should
2900 // it still contain a methdOop.
2901
2902 set_callee_target(NULL);
2903
2904 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2905 // If we have deferred set_locals there might be oops waiting to be
2906 // written
2907 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2908 if (list != NULL) {
2909 for (int i = 0; i < list->length(); i++) {
2910 list->at(i)->oops_do(f);
2911 }
2912 }
2913
2914 // Traverse instance variables at the end since the GC may be moving things
2915 // around using this function
2916 f->do_oop((oop*) &_threadObj);
2917 f->do_oop((oop*) &_vm_result);
2918 f->do_oop((oop*) &_exception_oop);
2919 f->do_oop((oop*) &_pending_async_exception);
2920
2921 if (jvmti_thread_state() != NULL) {
2922 jvmti_thread_state()->oops_do(f);
2923 }
2924 }
2925
2926 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2927 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2928 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2929
2930 if (has_last_Java_frame()) {
2931 // Traverse the execution stack
2932 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2933 fst.current()->nmethods_do(cf);
2934 }
2935 }
2936 }
2937
2938 void JavaThread::metadata_do(void f(Metadata*)) {
2939 if (has_last_Java_frame()) {
2940 // Traverse the execution stack to call f() on the methods in the stack
2941 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2942 fst.current()->metadata_do(f);
2943 }
2944 } else if (is_Compiler_thread()) {
2945 // need to walk ciMetadata in current compile tasks to keep alive.
2946 CompilerThread* ct = (CompilerThread*)this;
2947 if (ct->env() != NULL) {
2948 ct->env()->metadata_do(f);
2949 }
2950 CompileTask* task = ct->task();
2951 if (task != NULL) {
2952 task->metadata_do(f);
2953 }
2954 }
2955 }
2956
2957 // Printing
2958 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2959 switch (_thread_state) {
2960 case _thread_uninitialized: return "_thread_uninitialized";
2961 case _thread_new: return "_thread_new";
2962 case _thread_new_trans: return "_thread_new_trans";
2963 case _thread_in_native: return "_thread_in_native";
2964 case _thread_in_native_trans: return "_thread_in_native_trans";
2965 case _thread_in_vm: return "_thread_in_vm";
2966 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2967 case _thread_in_Java: return "_thread_in_Java";
2968 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2969 case _thread_blocked: return "_thread_blocked";
2970 case _thread_blocked_trans: return "_thread_blocked_trans";
2971 default: return "unknown thread state";
2972 }
2973 }
2974
2975 #ifndef PRODUCT
2976 void JavaThread::print_thread_state_on(outputStream *st) const {
2977 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2978 };
2979 void JavaThread::print_thread_state() const {
2980 print_thread_state_on(tty);
2981 }
2982 #endif // PRODUCT
2983
2984 // Called by Threads::print() for VM_PrintThreads operation
2985 void JavaThread::print_on(outputStream *st) const {
2986 st->print_raw("\"");
2987 st->print_raw(get_thread_name());
2988 st->print_raw("\" ");
2989 oop thread_oop = threadObj();
2990 if (thread_oop != NULL) {
2991 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
2992 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2993 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2994 }
2995 Thread::print_on(st);
2996 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2997 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2998 if (thread_oop != NULL) {
2999 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3000 }
3001 #ifndef PRODUCT
3002 print_thread_state_on(st);
3003 _safepoint_state->print_on(st);
3004 #endif // PRODUCT
3005 if (is_Compiler_thread()) {
3006 CompileTask *task = ((CompilerThread*)this)->task();
3007 if (task != NULL) {
3008 st->print(" Compiling: ");
3009 task->print(st, NULL, true, false);
3010 } else {
3011 st->print(" No compile task");
3012 }
3013 st->cr();
3014 }
3015 }
3016
3017 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3018 st->print("%s", get_thread_name_string(buf, buflen));
3019 }
3020
3021 // Called by fatal error handler. The difference between this and
3022 // JavaThread::print() is that we can't grab lock or allocate memory.
3023 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3024 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3025 oop thread_obj = threadObj();
3026 if (thread_obj != NULL) {
3027 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3028 }
3029 st->print(" [");
3030 st->print("%s", _get_thread_state_name(_thread_state));
3031 if (osthread()) {
3032 st->print(", id=%d", osthread()->thread_id());
3033 }
3034 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3035 p2i(stack_end()), p2i(stack_base()));
3036 st->print("]");
3037
3038 if (_threads_hazard_ptr != NULL) {
3039 st->print(" _threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
3040 }
3041 if (_nested_threads_hazard_ptr != NULL) {
3042 print_nested_threads_hazard_ptrs_on(st);
3043 }
3044 return;
3045 }
3046
3047 // Verification
3048
3049 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3050
3051 void JavaThread::verify() {
3052 // Verify oops in the thread.
3053 oops_do(&VerifyOopClosure::verify_oop, NULL);
3054
3055 // Verify the stack frames.
3056 frames_do(frame_verify);
3057 }
3058
3059 // CR 6300358 (sub-CR 2137150)
3060 // Most callers of this method assume that it can't return NULL but a
3061 // thread may not have a name whilst it is in the process of attaching to
3062 // the VM - see CR 6412693, and there are places where a JavaThread can be
3063 // seen prior to having it's threadObj set (eg JNI attaching threads and
3064 // if vm exit occurs during initialization). These cases can all be accounted
3065 // for such that this method never returns NULL.
3066 const char* JavaThread::get_thread_name() const {
3067 #ifdef ASSERT
3068 // early safepoints can hit while current thread does not yet have TLS
3069 if (!SafepointSynchronize::is_at_safepoint()) {
3070 Thread *cur = Thread::current();
3071 if (!(cur->is_Java_thread() && cur == this)) {
3072 // Current JavaThreads are allowed to get their own name without
3073 // the Threads_lock.
3074 assert_locked_or_safepoint(Threads_lock);
3075 }
3076 }
3077 #endif // ASSERT
3078 return get_thread_name_string();
3079 }
3080
3081 // Returns a non-NULL representation of this thread's name, or a suitable
3082 // descriptive string if there is no set name
3083 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3084 const char* name_str;
3085 oop thread_obj = threadObj();
3086 if (thread_obj != NULL) {
3087 oop name = java_lang_Thread::name(thread_obj);
3088 if (name != NULL) {
3089 if (buf == NULL) {
3090 name_str = java_lang_String::as_utf8_string(name);
3091 } else {
3092 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3093 }
3094 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3095 name_str = "<no-name - thread is attaching>";
3096 } else {
3097 name_str = Thread::name();
3098 }
3099 } else {
3100 name_str = Thread::name();
3101 }
3102 assert(name_str != NULL, "unexpected NULL thread name");
3103 return name_str;
3104 }
3105
3106
3107 const char* JavaThread::get_threadgroup_name() const {
3108 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3109 oop thread_obj = threadObj();
3110 if (thread_obj != NULL) {
3111 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3112 if (thread_group != NULL) {
3113 // ThreadGroup.name can be null
3114 return java_lang_ThreadGroup::name(thread_group);
3115 }
3116 }
3117 return NULL;
3118 }
3119
3120 const char* JavaThread::get_parent_name() const {
3121 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3122 oop thread_obj = threadObj();
3123 if (thread_obj != NULL) {
3124 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3125 if (thread_group != NULL) {
3126 oop parent = java_lang_ThreadGroup::parent(thread_group);
3127 if (parent != NULL) {
3128 // ThreadGroup.name can be null
3129 return java_lang_ThreadGroup::name(parent);
3130 }
3131 }
3132 }
3133 return NULL;
3134 }
3135
3136 ThreadPriority JavaThread::java_priority() const {
3137 oop thr_oop = threadObj();
3138 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3139 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3140 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3141 return priority;
3142 }
3143
3144 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3145
3146 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3147 // Link Java Thread object <-> C++ Thread
3148
3149 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3150 // and put it into a new Handle. The Handle "thread_oop" can then
3151 // be used to pass the C++ thread object to other methods.
3152
3153 // Set the Java level thread object (jthread) field of the
3154 // new thread (a JavaThread *) to C++ thread object using the
3155 // "thread_oop" handle.
3156
3157 // Set the thread field (a JavaThread *) of the
3158 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3159
3160 Handle thread_oop(Thread::current(),
3161 JNIHandles::resolve_non_null(jni_thread));
3162 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3163 "must be initialized");
3164 set_threadObj(thread_oop());
3165 java_lang_Thread::set_thread(thread_oop(), this);
3166
3167 if (prio == NoPriority) {
3168 prio = java_lang_Thread::priority(thread_oop());
3169 assert(prio != NoPriority, "A valid priority should be present");
3170 }
3171
3172 // Push the Java priority down to the native thread; needs Threads_lock
3173 Thread::set_priority(this, prio);
3174
3175 prepare_ext();
3176
3177 // Add the new thread to the Threads list and set it in motion.
3178 // We must have threads lock in order to call Threads::add.
3179 // It is crucial that we do not block before the thread is
3180 // added to the Threads list for if a GC happens, then the java_thread oop
3181 // will not be visited by GC.
3182 Threads::add(this);
3183 }
3184
3185 oop JavaThread::current_park_blocker() {
3186 // Support for JSR-166 locks
3187 oop thread_oop = threadObj();
3188 if (thread_oop != NULL &&
3189 JDK_Version::current().supports_thread_park_blocker()) {
3190 return java_lang_Thread::park_blocker(thread_oop);
3191 }
3192 return NULL;
3193 }
3194
3195
3196 void JavaThread::print_stack_on(outputStream* st) {
3197 if (!has_last_Java_frame()) return;
3198 ResourceMark rm;
3199 HandleMark hm;
3200
3201 RegisterMap reg_map(this);
3202 vframe* start_vf = last_java_vframe(®_map);
3203 int count = 0;
3204 for (vframe* f = start_vf; f; f = f->sender()) {
3205 if (f->is_java_frame()) {
3206 javaVFrame* jvf = javaVFrame::cast(f);
3207 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3208
3209 // Print out lock information
3210 if (JavaMonitorsInStackTrace) {
3211 jvf->print_lock_info_on(st, count);
3212 }
3213 } else {
3214 // Ignore non-Java frames
3215 }
3216
3217 // Bail-out case for too deep stacks
3218 count++;
3219 if (MaxJavaStackTraceDepth == count) return;
3220 }
3221 }
3222
3223
3224 // JVMTI PopFrame support
3225 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3226 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3227 if (in_bytes(size_in_bytes) != 0) {
3228 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3229 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3230 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3231 }
3232 }
3233
3234 void* JavaThread::popframe_preserved_args() {
3235 return _popframe_preserved_args;
3236 }
3237
3238 ByteSize JavaThread::popframe_preserved_args_size() {
3239 return in_ByteSize(_popframe_preserved_args_size);
3240 }
3241
3242 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3243 int sz = in_bytes(popframe_preserved_args_size());
3244 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3245 return in_WordSize(sz / wordSize);
3246 }
3247
3248 void JavaThread::popframe_free_preserved_args() {
3249 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3250 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3251 _popframe_preserved_args = NULL;
3252 _popframe_preserved_args_size = 0;
3253 }
3254
3255 #ifndef PRODUCT
3256
3257 void JavaThread::trace_frames() {
3258 tty->print_cr("[Describe stack]");
3259 int frame_no = 1;
3260 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3261 tty->print(" %d. ", frame_no++);
3262 fst.current()->print_value_on(tty, this);
3263 tty->cr();
3264 }
3265 }
3266
3267 class PrintAndVerifyOopClosure: public OopClosure {
3268 protected:
3269 template <class T> inline void do_oop_work(T* p) {
3270 oop obj = oopDesc::load_decode_heap_oop(p);
3271 if (obj == NULL) return;
3272 tty->print(INTPTR_FORMAT ": ", p2i(p));
3273 if (oopDesc::is_oop_or_null(obj)) {
3274 if (obj->is_objArray()) {
3275 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3276 } else {
3277 obj->print();
3278 }
3279 } else {
3280 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3281 }
3282 tty->cr();
3283 }
3284 public:
3285 virtual void do_oop(oop* p) { do_oop_work(p); }
3286 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3287 };
3288
3289
3290 static void oops_print(frame* f, const RegisterMap *map) {
3291 PrintAndVerifyOopClosure print;
3292 f->print_value();
3293 f->oops_do(&print, NULL, (RegisterMap*)map);
3294 }
3295
3296 // Print our all the locations that contain oops and whether they are
3297 // valid or not. This useful when trying to find the oldest frame
3298 // where an oop has gone bad since the frame walk is from youngest to
3299 // oldest.
3300 void JavaThread::trace_oops() {
3301 tty->print_cr("[Trace oops]");
3302 frames_do(oops_print);
3303 }
3304
3305
3306 #ifdef ASSERT
3307 // Print or validate the layout of stack frames
3308 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3309 ResourceMark rm;
3310 PRESERVE_EXCEPTION_MARK;
3311 FrameValues values;
3312 int frame_no = 0;
3313 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3314 fst.current()->describe(values, ++frame_no);
3315 if (depth == frame_no) break;
3316 }
3317 if (validate_only) {
3318 values.validate();
3319 } else {
3320 tty->print_cr("[Describe stack layout]");
3321 values.print(this);
3322 }
3323 }
3324 #endif
3325
3326 void JavaThread::trace_stack_from(vframe* start_vf) {
3327 ResourceMark rm;
3328 int vframe_no = 1;
3329 for (vframe* f = start_vf; f; f = f->sender()) {
3330 if (f->is_java_frame()) {
3331 javaVFrame::cast(f)->print_activation(vframe_no++);
3332 } else {
3333 f->print();
3334 }
3335 if (vframe_no > StackPrintLimit) {
3336 tty->print_cr("...<more frames>...");
3337 return;
3338 }
3339 }
3340 }
3341
3342
3343 void JavaThread::trace_stack() {
3344 if (!has_last_Java_frame()) return;
3345 ResourceMark rm;
3346 HandleMark hm;
3347 RegisterMap reg_map(this);
3348 trace_stack_from(last_java_vframe(®_map));
3349 }
3350
3351
3352 #endif // PRODUCT
3353
3354
3355 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3356 assert(reg_map != NULL, "a map must be given");
3357 frame f = last_frame();
3358 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3359 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3360 }
3361 return NULL;
3362 }
3363
3364
3365 Klass* JavaThread::security_get_caller_class(int depth) {
3366 vframeStream vfst(this);
3367 vfst.security_get_caller_frame(depth);
3368 if (!vfst.at_end()) {
3369 return vfst.method()->method_holder();
3370 }
3371 return NULL;
3372 }
3373
3374 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3375 assert(thread->is_Compiler_thread(), "must be compiler thread");
3376 CompileBroker::compiler_thread_loop();
3377 }
3378
3379 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3380 NMethodSweeper::sweeper_loop();
3381 }
3382
3383 // Create a CompilerThread
3384 CompilerThread::CompilerThread(CompileQueue* queue,
3385 CompilerCounters* counters)
3386 : JavaThread(&compiler_thread_entry) {
3387 _env = NULL;
3388 _log = NULL;
3389 _task = NULL;
3390 _queue = queue;
3391 _counters = counters;
3392 _buffer_blob = NULL;
3393 _compiler = NULL;
3394
3395 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3396 resource_area()->bias_to(mtCompiler);
3397
3398 #ifndef PRODUCT
3399 _ideal_graph_printer = NULL;
3400 #endif
3401 }
3402
3403 bool CompilerThread::can_call_java() const {
3404 return _compiler != NULL && _compiler->is_jvmci();
3405 }
3406
3407 // Create sweeper thread
3408 CodeCacheSweeperThread::CodeCacheSweeperThread()
3409 : JavaThread(&sweeper_thread_entry) {
3410 _scanned_compiled_method = NULL;
3411 }
3412
3413 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3414 JavaThread::oops_do(f, cf);
3415 if (_scanned_compiled_method != NULL && cf != NULL) {
3416 // Safepoints can occur when the sweeper is scanning an nmethod so
3417 // process it here to make sure it isn't unloaded in the middle of
3418 // a scan.
3419 cf->do_code_blob(_scanned_compiled_method);
3420 }
3421 }
3422
3423 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3424 JavaThread::nmethods_do(cf);
3425 if (_scanned_compiled_method != NULL && cf != NULL) {
3426 // Safepoints can occur when the sweeper is scanning an nmethod so
3427 // process it here to make sure it isn't unloaded in the middle of
3428 // a scan.
3429 cf->do_code_blob(_scanned_compiled_method);
3430 }
3431 }
3432
3433
3434 // ======= Threads ========
3435
3436 // The Threads class links together all active threads, and provides
3437 // operations over all threads. It is protected by the Threads_lock,
3438 // which is also used in other global contexts like safepointing.
3439 // ThreadsListHandles are used to safely perform operations on one
3440 // or more threads without the risk of the thread exiting during the
3441 // operation.
3442 //
3443 // Note: The Threads_lock is currently more widely used than we
3444 // would like. We are actively migrating Threads_lock uses to other
3445 // mechanisms in order to reduce Threads_lock contention.
3446
3447 JavaThread* Threads::_thread_list = NULL;
3448 int Threads::_number_of_threads = 0;
3449 int Threads::_number_of_non_daemon_threads = 0;
3450 int Threads::_return_code = 0;
3451 int Threads::_thread_claim_parity = 0;
3452 size_t JavaThread::_stack_size_at_create = 0;
3453
3454 #ifdef ASSERT
3455 bool Threads::_vm_complete = false;
3456 #endif
3457
3458 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3459 Prefetch::read((void*)addr, prefetch_interval);
3460 return *addr;
3461 }
3462
3463 // Possibly the ugliest for loop the world has seen. C++ does not allow
3464 // multiple types in the declaration section of the for loop. In this case
3465 // we are only dealing with pointers and hence can cast them. It looks ugly
3466 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3467 #define DO_JAVA_THREADS(LIST, X) \
3468 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3469 *MACRO_list = (JavaThread*)(LIST), \
3470 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3471 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3472 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3473 MACRO_current_p != MACRO_end; \
3474 MACRO_current_p++, \
3475 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3476
3477 // All JavaThreads
3478 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3479
3480 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3481 void Threads::threads_do(ThreadClosure* tc) {
3482 assert_locked_or_safepoint(Threads_lock);
3483 // ALL_JAVA_THREADS iterates through all JavaThreads
3484 ALL_JAVA_THREADS(p) {
3485 tc->do_thread(p);
3486 }
3487 // Someday we could have a table or list of all non-JavaThreads.
3488 // For now, just manually iterate through them.
3489 tc->do_thread(VMThread::vm_thread());
3490 Universe::heap()->gc_threads_do(tc);
3491 WatcherThread *wt = WatcherThread::watcher_thread();
3492 // Strictly speaking, the following NULL check isn't sufficient to make sure
3493 // the data for WatcherThread is still valid upon being examined. However,
3494 // considering that WatchThread terminates when the VM is on the way to
3495 // exit at safepoint, the chance of the above is extremely small. The right
3496 // way to prevent termination of WatcherThread would be to acquire
3497 // Terminator_lock, but we can't do that without violating the lock rank
3498 // checking in some cases.
3499 if (wt != NULL) {
3500 tc->do_thread(wt);
3501 }
3502
3503 // If CompilerThreads ever become non-JavaThreads, add them here
3504 }
3505
3506 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3507 int cp = Threads::thread_claim_parity();
3508 ALL_JAVA_THREADS(p) {
3509 if (p->claim_oops_do(is_par, cp)) {
3510 tc->do_thread(p);
3511 }
3512 }
3513 VMThread* vmt = VMThread::vm_thread();
3514 if (vmt->claim_oops_do(is_par, cp)) {
3515 tc->do_thread(vmt);
3516 }
3517 }
3518
3519 // The system initialization in the library has three phases.
3520 //
3521 // Phase 1: java.lang.System class initialization
3522 // java.lang.System is a primordial class loaded and initialized
3523 // by the VM early during startup. java.lang.System.<clinit>
3524 // only does registerNatives and keeps the rest of the class
3525 // initialization work later until thread initialization completes.
3526 //
3527 // System.initPhase1 initializes the system properties, the static
3528 // fields in, out, and err. Set up java signal handlers, OS-specific
3529 // system settings, and thread group of the main thread.
3530 static void call_initPhase1(TRAPS) {
3531 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3532 JavaValue result(T_VOID);
3533 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3534 vmSymbols::void_method_signature(), CHECK);
3535 }
3536
3537 // Phase 2. Module system initialization
3538 // This will initialize the module system. Only java.base classes
3539 // can be loaded until phase 2 completes.
3540 //
3541 // Call System.initPhase2 after the compiler initialization and jsr292
3542 // classes get initialized because module initialization runs a lot of java
3543 // code, that for performance reasons, should be compiled. Also, this will
3544 // enable the startup code to use lambda and other language features in this
3545 // phase and onward.
3546 //
3547 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3548 static void call_initPhase2(TRAPS) {
3549 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3550
3551 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3552
3553 JavaValue result(T_INT);
3554 JavaCallArguments args;
3555 args.push_int(DisplayVMOutputToStderr);
3556 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3557 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3558 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3559 if (result.get_jint() != JNI_OK) {
3560 vm_exit_during_initialization(); // no message or exception
3561 }
3562
3563 universe_post_module_init();
3564 }
3565
3566 // Phase 3. final setup - set security manager, system class loader and TCCL
3567 //
3568 // This will instantiate and set the security manager, set the system class
3569 // loader as well as the thread context class loader. The security manager
3570 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3571 // other modules or the application's classpath.
3572 static void call_initPhase3(TRAPS) {
3573 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3574 JavaValue result(T_VOID);
3575 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3576 vmSymbols::void_method_signature(), CHECK);
3577 }
3578
3579 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3580 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3581
3582 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3583 create_vm_init_libraries();
3584 }
3585
3586 initialize_class(vmSymbols::java_lang_String(), CHECK);
3587
3588 // Inject CompactStrings value after the static initializers for String ran.
3589 java_lang_String::set_compact_strings(CompactStrings);
3590
3591 // Initialize java_lang.System (needed before creating the thread)
3592 initialize_class(vmSymbols::java_lang_System(), CHECK);
3593 // The VM creates & returns objects of this class. Make sure it's initialized.
3594 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3595 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3596 Handle thread_group = create_initial_thread_group(CHECK);
3597 Universe::set_main_thread_group(thread_group());
3598 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3599 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3600 main_thread->set_threadObj(thread_object);
3601 // Set thread status to running since main thread has
3602 // been started and running.
3603 java_lang_Thread::set_thread_status(thread_object,
3604 java_lang_Thread::RUNNABLE);
3605
3606 // The VM creates objects of this class.
3607 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3608
3609 // The VM preresolves methods to these classes. Make sure that they get initialized
3610 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3611 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3612
3613 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3614 call_initPhase1(CHECK);
3615
3616 // get the Java runtime name after java.lang.System is initialized
3617 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3618 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3619
3620 // an instance of OutOfMemory exception has been allocated earlier
3621 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3622 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3623 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3624 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3625 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3626 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3627 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3628 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3629 }
3630
3631 void Threads::initialize_jsr292_core_classes(TRAPS) {
3632 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3633
3634 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3635 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3636 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3637 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3638 }
3639
3640 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3641 extern void JDK_Version_init();
3642
3643 // Preinitialize version info.
3644 VM_Version::early_initialize();
3645
3646 // Check version
3647 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3648
3649 // Initialize library-based TLS
3650 ThreadLocalStorage::init();
3651
3652 // Initialize the output stream module
3653 ostream_init();
3654
3655 // Process java launcher properties.
3656 Arguments::process_sun_java_launcher_properties(args);
3657
3658 // Initialize the os module
3659 os::init();
3660
3661 // Record VM creation timing statistics
3662 TraceVmCreationTime create_vm_timer;
3663 create_vm_timer.start();
3664
3665 // Initialize system properties.
3666 Arguments::init_system_properties();
3667
3668 // So that JDK version can be used as a discriminator when parsing arguments
3669 JDK_Version_init();
3670
3671 // Update/Initialize System properties after JDK version number is known
3672 Arguments::init_version_specific_system_properties();
3673
3674 // Make sure to initialize log configuration *before* parsing arguments
3675 LogConfiguration::initialize(create_vm_timer.begin_time());
3676
3677 // Parse arguments
3678 // Note: this internally calls os::init_container_support()
3679 jint parse_result = Arguments::parse(args);
3680 if (parse_result != JNI_OK) return parse_result;
3681
3682 os::init_before_ergo();
3683
3684 jint ergo_result = Arguments::apply_ergo();
3685 if (ergo_result != JNI_OK) return ergo_result;
3686
3687 // Final check of all ranges after ergonomics which may change values.
3688 if (!CommandLineFlagRangeList::check_ranges()) {
3689 return JNI_EINVAL;
3690 }
3691
3692 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3693 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3694 if (!constraint_result) {
3695 return JNI_EINVAL;
3696 }
3697
3698 CommandLineFlagWriteableList::mark_startup();
3699
3700 if (PauseAtStartup) {
3701 os::pause();
3702 }
3703
3704 HOTSPOT_VM_INIT_BEGIN();
3705
3706 // Timing (must come after argument parsing)
3707 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3708
3709 // Initialize the os module after parsing the args
3710 jint os_init_2_result = os::init_2();
3711 if (os_init_2_result != JNI_OK) return os_init_2_result;
3712
3713 SafepointMechanism::initialize();
3714
3715 jint adjust_after_os_result = Arguments::adjust_after_os();
3716 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3717
3718 // Initialize output stream logging
3719 ostream_init_log();
3720
3721 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3722 // Must be before create_vm_init_agents()
3723 if (Arguments::init_libraries_at_startup()) {
3724 convert_vm_init_libraries_to_agents();
3725 }
3726
3727 // Launch -agentlib/-agentpath and converted -Xrun agents
3728 if (Arguments::init_agents_at_startup()) {
3729 create_vm_init_agents();
3730 }
3731
3732 // Initialize Threads state
3733 _thread_list = NULL;
3734 _number_of_threads = 0;
3735 _number_of_non_daemon_threads = 0;
3736
3737 // Initialize global data structures and create system classes in heap
3738 vm_init_globals();
3739
3740 #if INCLUDE_JVMCI
3741 if (JVMCICounterSize > 0) {
3742 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3743 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3744 } else {
3745 JavaThread::_jvmci_old_thread_counters = NULL;
3746 }
3747 #endif // INCLUDE_JVMCI
3748
3749 // Attach the main thread to this os thread
3750 JavaThread* main_thread = new JavaThread();
3751 main_thread->set_thread_state(_thread_in_vm);
3752 main_thread->initialize_thread_current();
3753 // must do this before set_active_handles
3754 main_thread->record_stack_base_and_size();
3755 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3756
3757 if (!main_thread->set_as_starting_thread()) {
3758 vm_shutdown_during_initialization(
3759 "Failed necessary internal allocation. Out of swap space");
3760 main_thread->smr_delete();
3761 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3762 return JNI_ENOMEM;
3763 }
3764
3765 // Enable guard page *after* os::create_main_thread(), otherwise it would
3766 // crash Linux VM, see notes in os_linux.cpp.
3767 main_thread->create_stack_guard_pages();
3768
3769 // Initialize Java-Level synchronization subsystem
3770 ObjectMonitor::Initialize();
3771
3772 // Initialize global modules
3773 jint status = init_globals();
3774 if (status != JNI_OK) {
3775 main_thread->smr_delete();
3776 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3777 return status;
3778 }
3779
3780 if (TRACE_INITIALIZE() != JNI_OK) {
3781 vm_exit_during_initialization("Failed to initialize tracing backend");
3782 }
3783
3784 // Should be done after the heap is fully created
3785 main_thread->cache_global_variables();
3786
3787 HandleMark hm;
3788
3789 { MutexLocker mu(Threads_lock);
3790 Threads::add(main_thread);
3791 }
3792
3793 // Any JVMTI raw monitors entered in onload will transition into
3794 // real raw monitor. VM is setup enough here for raw monitor enter.
3795 JvmtiExport::transition_pending_onload_raw_monitors();
3796
3797 // Create the VMThread
3798 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3799
3800 VMThread::create();
3801 Thread* vmthread = VMThread::vm_thread();
3802
3803 if (!os::create_thread(vmthread, os::vm_thread)) {
3804 vm_exit_during_initialization("Cannot create VM thread. "
3805 "Out of system resources.");
3806 }
3807
3808 // Wait for the VM thread to become ready, and VMThread::run to initialize
3809 // Monitors can have spurious returns, must always check another state flag
3810 {
3811 MutexLocker ml(Notify_lock);
3812 os::start_thread(vmthread);
3813 while (vmthread->active_handles() == NULL) {
3814 Notify_lock->wait();
3815 }
3816 }
3817 }
3818
3819 assert(Universe::is_fully_initialized(), "not initialized");
3820 if (VerifyDuringStartup) {
3821 // Make sure we're starting with a clean slate.
3822 VM_Verify verify_op;
3823 VMThread::execute(&verify_op);
3824 }
3825
3826 Thread* THREAD = Thread::current();
3827
3828 // Always call even when there are not JVMTI environments yet, since environments
3829 // may be attached late and JVMTI must track phases of VM execution
3830 JvmtiExport::enter_early_start_phase();
3831
3832 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3833 JvmtiExport::post_early_vm_start();
3834
3835 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3836
3837 // We need this for ClassDataSharing - the initial vm.info property is set
3838 // with the default value of CDS "sharing" which may be reset through
3839 // command line options.
3840 reset_vm_info_property(CHECK_JNI_ERR);
3841
3842 quicken_jni_functions();
3843
3844 // No more stub generation allowed after that point.
3845 StubCodeDesc::freeze();
3846
3847 // Set flag that basic initialization has completed. Used by exceptions and various
3848 // debug stuff, that does not work until all basic classes have been initialized.
3849 set_init_completed();
3850
3851 LogConfiguration::post_initialize();
3852 Metaspace::post_initialize();
3853
3854 HOTSPOT_VM_INIT_END();
3855
3856 // record VM initialization completion time
3857 #if INCLUDE_MANAGEMENT
3858 Management::record_vm_init_completed();
3859 #endif // INCLUDE_MANAGEMENT
3860
3861 // Signal Dispatcher needs to be started before VMInit event is posted
3862 os::signal_init(CHECK_JNI_ERR);
3863
3864 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3865 if (!DisableAttachMechanism) {
3866 AttachListener::vm_start();
3867 if (StartAttachListener || AttachListener::init_at_startup()) {
3868 AttachListener::init();
3869 }
3870 }
3871
3872 // Launch -Xrun agents
3873 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3874 // back-end can launch with -Xdebug -Xrunjdwp.
3875 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3876 create_vm_init_libraries();
3877 }
3878
3879 if (CleanChunkPoolAsync) {
3880 Chunk::start_chunk_pool_cleaner_task();
3881 }
3882
3883 // initialize compiler(s)
3884 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3885 CompileBroker::compilation_init(CHECK_JNI_ERR);
3886 #endif
3887
3888 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3889 // It is done after compilers are initialized, because otherwise compilations of
3890 // signature polymorphic MH intrinsics can be missed
3891 // (see SystemDictionary::find_method_handle_intrinsic).
3892 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3893
3894 // This will initialize the module system. Only java.base classes can be
3895 // loaded until phase 2 completes
3896 call_initPhase2(CHECK_JNI_ERR);
3897
3898 // Always call even when there are not JVMTI environments yet, since environments
3899 // may be attached late and JVMTI must track phases of VM execution
3900 JvmtiExport::enter_start_phase();
3901
3902 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3903 JvmtiExport::post_vm_start();
3904
3905 // Final system initialization including security manager and system class loader
3906 call_initPhase3(CHECK_JNI_ERR);
3907
3908 // cache the system and platform class loaders
3909 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3910
3911 #if INCLUDE_JVMCI
3912 if (EnableJVMCI) {
3913 // Initialize JVMCI eagerly if JVMCIPrintProperties is enabled.
3914 // The JVMCI Java initialization code will read this flag and
3915 // do the printing if it's set.
3916 bool init = JVMCIPrintProperties;
3917
3918 if (!init) {
3919 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3920 // compilations via JVMCI will not actually block until JVMCI is initialized.
3921 init = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3922 }
3923
3924 if (init) {
3925 JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
3926 }
3927 }
3928 #endif
3929
3930 // Always call even when there are not JVMTI environments yet, since environments
3931 // may be attached late and JVMTI must track phases of VM execution
3932 JvmtiExport::enter_live_phase();
3933
3934 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3935 JvmtiExport::post_vm_initialized();
3936
3937 if (TRACE_START() != JNI_OK) {
3938 vm_exit_during_initialization("Failed to start tracing backend.");
3939 }
3940
3941 #if INCLUDE_MANAGEMENT
3942 Management::initialize(THREAD);
3943
3944 if (HAS_PENDING_EXCEPTION) {
3945 // management agent fails to start possibly due to
3946 // configuration problem and is responsible for printing
3947 // stack trace if appropriate. Simply exit VM.
3948 vm_exit(1);
3949 }
3950 #endif // INCLUDE_MANAGEMENT
3951
3952 if (MemProfiling) MemProfiler::engage();
3953 StatSampler::engage();
3954 if (CheckJNICalls) JniPeriodicChecker::engage();
3955
3956 BiasedLocking::init();
3957
3958 #if INCLUDE_RTM_OPT
3959 RTMLockingCounters::init();
3960 #endif
3961
3962 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3963 call_postVMInitHook(THREAD);
3964 // The Java side of PostVMInitHook.run must deal with all
3965 // exceptions and provide means of diagnosis.
3966 if (HAS_PENDING_EXCEPTION) {
3967 CLEAR_PENDING_EXCEPTION;
3968 }
3969 }
3970
3971 {
3972 MutexLocker ml(PeriodicTask_lock);
3973 // Make sure the WatcherThread can be started by WatcherThread::start()
3974 // or by dynamic enrollment.
3975 WatcherThread::make_startable();
3976 // Start up the WatcherThread if there are any periodic tasks
3977 // NOTE: All PeriodicTasks should be registered by now. If they
3978 // aren't, late joiners might appear to start slowly (we might
3979 // take a while to process their first tick).
3980 if (PeriodicTask::num_tasks() > 0) {
3981 WatcherThread::start();
3982 }
3983 }
3984
3985 create_vm_timer.end();
3986 #ifdef ASSERT
3987 _vm_complete = true;
3988 #endif
3989
3990 if (DumpSharedSpaces) {
3991 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3992 ShouldNotReachHere();
3993 }
3994
3995 return JNI_OK;
3996 }
3997
3998 // type for the Agent_OnLoad and JVM_OnLoad entry points
3999 extern "C" {
4000 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4001 }
4002 // Find a command line agent library and return its entry point for
4003 // -agentlib: -agentpath: -Xrun
4004 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4005 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4006 const char *on_load_symbols[],
4007 size_t num_symbol_entries) {
4008 OnLoadEntry_t on_load_entry = NULL;
4009 void *library = NULL;
4010
4011 if (!agent->valid()) {
4012 char buffer[JVM_MAXPATHLEN];
4013 char ebuf[1024] = "";
4014 const char *name = agent->name();
4015 const char *msg = "Could not find agent library ";
4016
4017 // First check to see if agent is statically linked into executable
4018 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4019 library = agent->os_lib();
4020 } else if (agent->is_absolute_path()) {
4021 library = os::dll_load(name, ebuf, sizeof ebuf);
4022 if (library == NULL) {
4023 const char *sub_msg = " in absolute path, with error: ";
4024 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4025 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4026 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4027 // If we can't find the agent, exit.
4028 vm_exit_during_initialization(buf, NULL);
4029 FREE_C_HEAP_ARRAY(char, buf);
4030 }
4031 } else {
4032 // Try to load the agent from the standard dll directory
4033 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4034 name)) {
4035 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4036 }
4037 if (library == NULL) { // Try the library path directory.
4038 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4039 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4040 }
4041 if (library == NULL) {
4042 const char *sub_msg = " on the library path, with error: ";
4043 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4044
4045 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4046 strlen(ebuf) + strlen(sub_msg2) + 1;
4047 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4048 if (!agent->is_instrument_lib()) {
4049 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4050 } else {
4051 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4052 }
4053 // If we can't find the agent, exit.
4054 vm_exit_during_initialization(buf, NULL);
4055 FREE_C_HEAP_ARRAY(char, buf);
4056 }
4057 }
4058 }
4059 agent->set_os_lib(library);
4060 agent->set_valid();
4061 }
4062
4063 // Find the OnLoad function.
4064 on_load_entry =
4065 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4066 false,
4067 on_load_symbols,
4068 num_symbol_entries));
4069 return on_load_entry;
4070 }
4071
4072 // Find the JVM_OnLoad entry point
4073 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4074 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4075 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4076 }
4077
4078 // Find the Agent_OnLoad entry point
4079 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4080 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4081 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4082 }
4083
4084 // For backwards compatibility with -Xrun
4085 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4086 // treated like -agentpath:
4087 // Must be called before agent libraries are created
4088 void Threads::convert_vm_init_libraries_to_agents() {
4089 AgentLibrary* agent;
4090 AgentLibrary* next;
4091
4092 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4093 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4094 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4095
4096 // If there is an JVM_OnLoad function it will get called later,
4097 // otherwise see if there is an Agent_OnLoad
4098 if (on_load_entry == NULL) {
4099 on_load_entry = lookup_agent_on_load(agent);
4100 if (on_load_entry != NULL) {
4101 // switch it to the agent list -- so that Agent_OnLoad will be called,
4102 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4103 Arguments::convert_library_to_agent(agent);
4104 } else {
4105 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4106 }
4107 }
4108 }
4109 }
4110
4111 // Create agents for -agentlib: -agentpath: and converted -Xrun
4112 // Invokes Agent_OnLoad
4113 // Called very early -- before JavaThreads exist
4114 void Threads::create_vm_init_agents() {
4115 extern struct JavaVM_ main_vm;
4116 AgentLibrary* agent;
4117
4118 JvmtiExport::enter_onload_phase();
4119
4120 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4121 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4122
4123 if (on_load_entry != NULL) {
4124 // Invoke the Agent_OnLoad function
4125 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4126 if (err != JNI_OK) {
4127 vm_exit_during_initialization("agent library failed to init", agent->name());
4128 }
4129 } else {
4130 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4131 }
4132 }
4133 JvmtiExport::enter_primordial_phase();
4134 }
4135
4136 extern "C" {
4137 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4138 }
4139
4140 void Threads::shutdown_vm_agents() {
4141 // Send any Agent_OnUnload notifications
4142 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4143 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4144 extern struct JavaVM_ main_vm;
4145 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4146
4147 // Find the Agent_OnUnload function.
4148 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4149 os::find_agent_function(agent,
4150 false,
4151 on_unload_symbols,
4152 num_symbol_entries));
4153
4154 // Invoke the Agent_OnUnload function
4155 if (unload_entry != NULL) {
4156 JavaThread* thread = JavaThread::current();
4157 ThreadToNativeFromVM ttn(thread);
4158 HandleMark hm(thread);
4159 (*unload_entry)(&main_vm);
4160 }
4161 }
4162 }
4163
4164 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4165 // Invokes JVM_OnLoad
4166 void Threads::create_vm_init_libraries() {
4167 extern struct JavaVM_ main_vm;
4168 AgentLibrary* agent;
4169
4170 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4171 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4172
4173 if (on_load_entry != NULL) {
4174 // Invoke the JVM_OnLoad function
4175 JavaThread* thread = JavaThread::current();
4176 ThreadToNativeFromVM ttn(thread);
4177 HandleMark hm(thread);
4178 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4179 if (err != JNI_OK) {
4180 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4181 }
4182 } else {
4183 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4184 }
4185 }
4186 }
4187
4188
4189 // Last thread running calls java.lang.Shutdown.shutdown()
4190 void JavaThread::invoke_shutdown_hooks() {
4191 HandleMark hm(this);
4192
4193 // We could get here with a pending exception, if so clear it now.
4194 if (this->has_pending_exception()) {
4195 this->clear_pending_exception();
4196 }
4197
4198 EXCEPTION_MARK;
4199 Klass* shutdown_klass =
4200 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4201 THREAD);
4202 if (shutdown_klass != NULL) {
4203 // SystemDictionary::resolve_or_null will return null if there was
4204 // an exception. If we cannot load the Shutdown class, just don't
4205 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4206 // and finalizers (if runFinalizersOnExit is set) won't be run.
4207 // Note that if a shutdown hook was registered or runFinalizersOnExit
4208 // was called, the Shutdown class would have already been loaded
4209 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
4210 JavaValue result(T_VOID);
4211 JavaCalls::call_static(&result,
4212 shutdown_klass,
4213 vmSymbols::shutdown_method_name(),
4214 vmSymbols::void_method_signature(),
4215 THREAD);
4216 }
4217 CLEAR_PENDING_EXCEPTION;
4218 }
4219
4220 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4221 // the program falls off the end of main(). Another VM exit path is through
4222 // vm_exit() when the program calls System.exit() to return a value or when
4223 // there is a serious error in VM. The two shutdown paths are not exactly
4224 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4225 // and VM_Exit op at VM level.
4226 //
4227 // Shutdown sequence:
4228 // + Shutdown native memory tracking if it is on
4229 // + Wait until we are the last non-daemon thread to execute
4230 // <-- every thing is still working at this moment -->
4231 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4232 // shutdown hooks, run finalizers if finalization-on-exit
4233 // + Call before_exit(), prepare for VM exit
4234 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4235 // currently the only user of this mechanism is File.deleteOnExit())
4236 // > stop StatSampler, watcher thread, CMS threads,
4237 // post thread end and vm death events to JVMTI,
4238 // stop signal thread
4239 // + Call JavaThread::exit(), it will:
4240 // > release JNI handle blocks, remove stack guard pages
4241 // > remove this thread from Threads list
4242 // <-- no more Java code from this thread after this point -->
4243 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4244 // the compiler threads at safepoint
4245 // <-- do not use anything that could get blocked by Safepoint -->
4246 // + Disable tracing at JNI/JVM barriers
4247 // + Set _vm_exited flag for threads that are still running native code
4248 // + Delete this thread
4249 // + Call exit_globals()
4250 // > deletes tty
4251 // > deletes PerfMemory resources
4252 // + Return to caller
4253
4254 bool Threads::destroy_vm() {
4255 JavaThread* thread = JavaThread::current();
4256
4257 #ifdef ASSERT
4258 _vm_complete = false;
4259 #endif
4260 // Wait until we are the last non-daemon thread to execute
4261 { MutexLocker nu(Threads_lock);
4262 while (Threads::number_of_non_daemon_threads() > 1)
4263 // This wait should make safepoint checks, wait without a timeout,
4264 // and wait as a suspend-equivalent condition.
4265 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4266 Mutex::_as_suspend_equivalent_flag);
4267 }
4268
4269 // Hang forever on exit if we are reporting an error.
4270 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4271 os::infinite_sleep();
4272 }
4273 os::wait_for_keypress_at_exit();
4274
4275 // run Java level shutdown hooks
4276 thread->invoke_shutdown_hooks();
4277
4278 before_exit(thread);
4279
4280 thread->exit(true);
4281
4282 // Stop VM thread.
4283 {
4284 // 4945125 The vm thread comes to a safepoint during exit.
4285 // GC vm_operations can get caught at the safepoint, and the
4286 // heap is unparseable if they are caught. Grab the Heap_lock
4287 // to prevent this. The GC vm_operations will not be able to
4288 // queue until after the vm thread is dead. After this point,
4289 // we'll never emerge out of the safepoint before the VM exits.
4290
4291 MutexLocker ml(Heap_lock);
4292
4293 VMThread::wait_for_vm_thread_exit();
4294 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4295 VMThread::destroy();
4296 }
4297
4298 // clean up ideal graph printers
4299 #if defined(COMPILER2) && !defined(PRODUCT)
4300 IdealGraphPrinter::clean_up();
4301 #endif
4302
4303 // Now, all Java threads are gone except daemon threads. Daemon threads
4304 // running Java code or in VM are stopped by the Safepoint. However,
4305 // daemon threads executing native code are still running. But they
4306 // will be stopped at native=>Java/VM barriers. Note that we can't
4307 // simply kill or suspend them, as it is inherently deadlock-prone.
4308
4309 VM_Exit::set_vm_exited();
4310
4311 notify_vm_shutdown();
4312
4313 // We are after VM_Exit::set_vm_exited() so we can't call
4314 // thread->smr_delete() or we will block on the Threads_lock.
4315 // Deleting the shutdown thread here is safe because another
4316 // JavaThread cannot have an active ThreadsListHandle for
4317 // this JavaThread.
4318 delete thread;
4319
4320 #if INCLUDE_JVMCI
4321 if (JVMCICounterSize > 0) {
4322 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4323 }
4324 #endif
4325
4326 // exit_globals() will delete tty
4327 exit_globals();
4328
4329 LogConfiguration::finalize();
4330
4331 return true;
4332 }
4333
4334
4335 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4336 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4337 return is_supported_jni_version(version);
4338 }
4339
4340
4341 jboolean Threads::is_supported_jni_version(jint version) {
4342 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4343 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4344 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4345 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4346 if (version == JNI_VERSION_9) return JNI_TRUE;
4347 if (version == JNI_VERSION_10) return JNI_TRUE;
4348 return JNI_FALSE;
4349 }
4350
4351
4352 void Threads::add(JavaThread* p, bool force_daemon) {
4353 // The threads lock must be owned at this point
4354 assert_locked_or_safepoint(Threads_lock);
4355
4356 // See the comment for this method in thread.hpp for its purpose and
4357 // why it is called here.
4358 p->initialize_queues();
4359 p->set_next(_thread_list);
4360 _thread_list = p;
4361
4362 // Once a JavaThread is added to the Threads list, smr_delete() has
4363 // to be used to delete it. Otherwise we can just delete it directly.
4364 p->set_on_thread_list();
4365
4366 _number_of_threads++;
4367 oop threadObj = p->threadObj();
4368 bool daemon = true;
4369 // Bootstrapping problem: threadObj can be null for initial
4370 // JavaThread (or for threads attached via JNI)
4371 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4372 _number_of_non_daemon_threads++;
4373 daemon = false;
4374 }
4375
4376 ThreadService::add_thread(p, daemon);
4377
4378 // Maintain fast thread list
4379 ThreadsSMRSupport::add_thread(p);
4380
4381 // Possible GC point.
4382 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4383 }
4384
4385 void Threads::remove(JavaThread* p) {
4386
4387 // Reclaim the objectmonitors from the omInUseList and omFreeList of the moribund thread.
4388 ObjectSynchronizer::omFlush(p);
4389
4390 // Extra scope needed for Thread_lock, so we can check
4391 // that we do not remove thread without safepoint code notice
4392 { MutexLocker ml(Threads_lock);
4393
4394 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4395
4396 // Maintain fast thread list
4397 ThreadsSMRSupport::remove_thread(p);
4398
4399 JavaThread* current = _thread_list;
4400 JavaThread* prev = NULL;
4401
4402 while (current != p) {
4403 prev = current;
4404 current = current->next();
4405 }
4406
4407 if (prev) {
4408 prev->set_next(current->next());
4409 } else {
4410 _thread_list = p->next();
4411 }
4412
4413 _number_of_threads--;
4414 oop threadObj = p->threadObj();
4415 bool daemon = true;
4416 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4417 _number_of_non_daemon_threads--;
4418 daemon = false;
4419
4420 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4421 // on destroy_vm will wake up.
4422 if (number_of_non_daemon_threads() == 1) {
4423 Threads_lock->notify_all();
4424 }
4425 }
4426 ThreadService::remove_thread(p, daemon);
4427
4428 // Make sure that safepoint code disregard this thread. This is needed since
4429 // the thread might mess around with locks after this point. This can cause it
4430 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4431 // of this thread since it is removed from the queue.
4432 p->set_terminated_value();
4433 } // unlock Threads_lock
4434
4435 // Since Events::log uses a lock, we grab it outside the Threads_lock
4436 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4437 }
4438
4439 // Operations on the Threads list for GC. These are not explicitly locked,
4440 // but the garbage collector must provide a safe context for them to run.
4441 // In particular, these things should never be called when the Threads_lock
4442 // is held by some other thread. (Note: the Safepoint abstraction also
4443 // uses the Threads_lock to guarantee this property. It also makes sure that
4444 // all threads gets blocked when exiting or starting).
4445
4446 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4447 ALL_JAVA_THREADS(p) {
4448 p->oops_do(f, cf);
4449 }
4450 VMThread::vm_thread()->oops_do(f, cf);
4451 }
4452
4453 void Threads::change_thread_claim_parity() {
4454 // Set the new claim parity.
4455 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4456 "Not in range.");
4457 _thread_claim_parity++;
4458 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4459 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4460 "Not in range.");
4461 }
4462
4463 #ifdef ASSERT
4464 void Threads::assert_all_threads_claimed() {
4465 ALL_JAVA_THREADS(p) {
4466 const int thread_parity = p->oops_do_parity();
4467 assert((thread_parity == _thread_claim_parity),
4468 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4469 }
4470 VMThread* vmt = VMThread::vm_thread();
4471 const int thread_parity = vmt->oops_do_parity();
4472 assert((thread_parity == _thread_claim_parity),
4473 "VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
4474 }
4475 #endif // ASSERT
4476
4477 class ParallelOopsDoThreadClosure : public ThreadClosure {
4478 private:
4479 OopClosure* _f;
4480 CodeBlobClosure* _cf;
4481 public:
4482 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4483 void do_thread(Thread* t) {
4484 t->oops_do(_f, _cf);
4485 }
4486 };
4487
4488 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4489 ParallelOopsDoThreadClosure tc(f, cf);
4490 possibly_parallel_threads_do(is_par, &tc);
4491 }
4492
4493 #if INCLUDE_ALL_GCS
4494 // Used by ParallelScavenge
4495 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4496 ALL_JAVA_THREADS(p) {
4497 q->enqueue(new ThreadRootsTask(p));
4498 }
4499 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4500 }
4501
4502 // Used by Parallel Old
4503 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4504 ALL_JAVA_THREADS(p) {
4505 q->enqueue(new ThreadRootsMarkingTask(p));
4506 }
4507 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4508 }
4509 #endif // INCLUDE_ALL_GCS
4510
4511 void Threads::nmethods_do(CodeBlobClosure* cf) {
4512 ALL_JAVA_THREADS(p) {
4513 // This is used by the code cache sweeper to mark nmethods that are active
4514 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4515 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4516 if(!p->is_Code_cache_sweeper_thread()) {
4517 p->nmethods_do(cf);
4518 }
4519 }
4520 }
4521
4522 void Threads::metadata_do(void f(Metadata*)) {
4523 ALL_JAVA_THREADS(p) {
4524 p->metadata_do(f);
4525 }
4526 }
4527
4528 class ThreadHandlesClosure : public ThreadClosure {
4529 void (*_f)(Metadata*);
4530 public:
4531 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4532 virtual void do_thread(Thread* thread) {
4533 thread->metadata_handles_do(_f);
4534 }
4535 };
4536
4537 void Threads::metadata_handles_do(void f(Metadata*)) {
4538 // Only walk the Handles in Thread.
4539 ThreadHandlesClosure handles_closure(f);
4540 threads_do(&handles_closure);
4541 }
4542
4543 void Threads::deoptimized_wrt_marked_nmethods() {
4544 ALL_JAVA_THREADS(p) {
4545 p->deoptimized_wrt_marked_nmethods();
4546 }
4547 }
4548
4549
4550 // Get count Java threads that are waiting to enter the specified monitor.
4551 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4552 int count,
4553 address monitor) {
4554 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4555
4556 int i = 0;
4557 DO_JAVA_THREADS(t_list, p) {
4558 if (!p->can_call_java()) continue;
4559
4560 address pending = (address)p->current_pending_monitor();
4561 if (pending == monitor) { // found a match
4562 if (i < count) result->append(p); // save the first count matches
4563 i++;
4564 }
4565 }
4566
4567 return result;
4568 }
4569
4570
4571 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4572 address owner) {
4573 // NULL owner means not locked so we can skip the search
4574 if (owner == NULL) return NULL;
4575
4576 DO_JAVA_THREADS(t_list, p) {
4577 // first, see if owner is the address of a Java thread
4578 if (owner == (address)p) return p;
4579 }
4580
4581 // Cannot assert on lack of success here since this function may be
4582 // used by code that is trying to report useful problem information
4583 // like deadlock detection.
4584 if (UseHeavyMonitors) return NULL;
4585
4586 // If we didn't find a matching Java thread and we didn't force use of
4587 // heavyweight monitors, then the owner is the stack address of the
4588 // Lock Word in the owning Java thread's stack.
4589 //
4590 JavaThread* the_owner = NULL;
4591 DO_JAVA_THREADS(t_list, q) {
4592 if (q->is_lock_owned(owner)) {
4593 the_owner = q;
4594 break;
4595 }
4596 }
4597
4598 // cannot assert on lack of success here; see above comment
4599 return the_owner;
4600 }
4601
4602 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4603 void Threads::print_on(outputStream* st, bool print_stacks,
4604 bool internal_format, bool print_concurrent_locks) {
4605 char buf[32];
4606 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4607
4608 st->print_cr("Full thread dump %s (%s %s):",
4609 Abstract_VM_Version::vm_name(),
4610 Abstract_VM_Version::vm_release(),
4611 Abstract_VM_Version::vm_info_string());
4612 st->cr();
4613
4614 #if INCLUDE_SERVICES
4615 // Dump concurrent locks
4616 ConcurrentLocksDump concurrent_locks;
4617 if (print_concurrent_locks) {
4618 concurrent_locks.dump_at_safepoint();
4619 }
4620 #endif // INCLUDE_SERVICES
4621
4622 ThreadsSMRSupport::print_info_on(st);
4623 st->cr();
4624
4625 ALL_JAVA_THREADS(p) {
4626 ResourceMark rm;
4627 p->print_on(st);
4628 if (print_stacks) {
4629 if (internal_format) {
4630 p->trace_stack();
4631 } else {
4632 p->print_stack_on(st);
4633 }
4634 }
4635 st->cr();
4636 #if INCLUDE_SERVICES
4637 if (print_concurrent_locks) {
4638 concurrent_locks.print_locks_on(p, st);
4639 }
4640 #endif // INCLUDE_SERVICES
4641 }
4642
4643 VMThread::vm_thread()->print_on(st);
4644 st->cr();
4645 Universe::heap()->print_gc_threads_on(st);
4646 WatcherThread* wt = WatcherThread::watcher_thread();
4647 if (wt != NULL) {
4648 wt->print_on(st);
4649 st->cr();
4650 }
4651
4652 st->flush();
4653 }
4654
4655 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4656 int buflen, bool* found_current) {
4657 if (this_thread != NULL) {
4658 bool is_current = (current == this_thread);
4659 *found_current = *found_current || is_current;
4660 st->print("%s", is_current ? "=>" : " ");
4661
4662 st->print(PTR_FORMAT, p2i(this_thread));
4663 st->print(" ");
4664 this_thread->print_on_error(st, buf, buflen);
4665 st->cr();
4666 }
4667 }
4668
4669 class PrintOnErrorClosure : public ThreadClosure {
4670 outputStream* _st;
4671 Thread* _current;
4672 char* _buf;
4673 int _buflen;
4674 bool* _found_current;
4675 public:
4676 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4677 int buflen, bool* found_current) :
4678 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4679
4680 virtual void do_thread(Thread* thread) {
4681 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4682 }
4683 };
4684
4685 // Threads::print_on_error() is called by fatal error handler. It's possible
4686 // that VM is not at safepoint and/or current thread is inside signal handler.
4687 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4688 // memory (even in resource area), it might deadlock the error handler.
4689 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4690 int buflen) {
4691 ThreadsSMRSupport::print_info_on(st);
4692 st->cr();
4693
4694 bool found_current = false;
4695 st->print_cr("Java Threads: ( => current thread )");
4696 ALL_JAVA_THREADS(thread) {
4697 print_on_error(thread, st, current, buf, buflen, &found_current);
4698 }
4699 st->cr();
4700
4701 st->print_cr("Other Threads:");
4702 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4703 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4704
4705 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4706 Universe::heap()->gc_threads_do(&print_closure);
4707
4708 if (!found_current) {
4709 st->cr();
4710 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4711 current->print_on_error(st, buf, buflen);
4712 st->cr();
4713 }
4714 st->cr();
4715
4716 st->print_cr("Threads with active compile tasks:");
4717 print_threads_compiling(st, buf, buflen);
4718 }
4719
4720 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) {
4721 ALL_JAVA_THREADS(thread) {
4722 if (thread->is_Compiler_thread()) {
4723 CompilerThread* ct = (CompilerThread*) thread;
4724
4725 // Keep task in local variable for NULL check.
4726 // ct->_task might be set to NULL by concurring compiler thread
4727 // because it completed the compilation. The task is never freed,
4728 // though, just returned to a free list.
4729 CompileTask* task = ct->task();
4730 if (task != NULL) {
4731 thread->print_name_on_error(st, buf, buflen);
4732 task->print(st, NULL, true, true);
4733 }
4734 }
4735 }
4736 }
4737
4738
4739 // Internal SpinLock and Mutex
4740 // Based on ParkEvent
4741
4742 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4743 //
4744 // We employ SpinLocks _only for low-contention, fixed-length
4745 // short-duration critical sections where we're concerned
4746 // about native mutex_t or HotSpot Mutex:: latency.
4747 // The mux construct provides a spin-then-block mutual exclusion
4748 // mechanism.
4749 //
4750 // Testing has shown that contention on the ListLock guarding gFreeList
4751 // is common. If we implement ListLock as a simple SpinLock it's common
4752 // for the JVM to devolve to yielding with little progress. This is true
4753 // despite the fact that the critical sections protected by ListLock are
4754 // extremely short.
4755 //
4756 // TODO-FIXME: ListLock should be of type SpinLock.
4757 // We should make this a 1st-class type, integrated into the lock
4758 // hierarchy as leaf-locks. Critically, the SpinLock structure
4759 // should have sufficient padding to avoid false-sharing and excessive
4760 // cache-coherency traffic.
4761
4762
4763 typedef volatile int SpinLockT;
4764
4765 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4766 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4767 return; // normal fast-path return
4768 }
4769
4770 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4771 TEVENT(SpinAcquire - ctx);
4772 int ctr = 0;
4773 int Yields = 0;
4774 for (;;) {
4775 while (*adr != 0) {
4776 ++ctr;
4777 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4778 if (Yields > 5) {
4779 os::naked_short_sleep(1);
4780 } else {
4781 os::naked_yield();
4782 ++Yields;
4783 }
4784 } else {
4785 SpinPause();
4786 }
4787 }
4788 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4789 }
4790 }
4791
4792 void Thread::SpinRelease(volatile int * adr) {
4793 assert(*adr != 0, "invariant");
4794 OrderAccess::fence(); // guarantee at least release consistency.
4795 // Roach-motel semantics.
4796 // It's safe if subsequent LDs and STs float "up" into the critical section,
4797 // but prior LDs and STs within the critical section can't be allowed
4798 // to reorder or float past the ST that releases the lock.
4799 // Loads and stores in the critical section - which appear in program
4800 // order before the store that releases the lock - must also appear
4801 // before the store that releases the lock in memory visibility order.
4802 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4803 // the ST of 0 into the lock-word which releases the lock, so fence
4804 // more than covers this on all platforms.
4805 *adr = 0;
4806 }
4807
4808 // muxAcquire and muxRelease:
4809 //
4810 // * muxAcquire and muxRelease support a single-word lock-word construct.
4811 // The LSB of the word is set IFF the lock is held.
4812 // The remainder of the word points to the head of a singly-linked list
4813 // of threads blocked on the lock.
4814 //
4815 // * The current implementation of muxAcquire-muxRelease uses its own
4816 // dedicated Thread._MuxEvent instance. If we're interested in
4817 // minimizing the peak number of extant ParkEvent instances then
4818 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4819 // as certain invariants were satisfied. Specifically, care would need
4820 // to be taken with regards to consuming unpark() "permits".
4821 // A safe rule of thumb is that a thread would never call muxAcquire()
4822 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4823 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4824 // consume an unpark() permit intended for monitorenter, for instance.
4825 // One way around this would be to widen the restricted-range semaphore
4826 // implemented in park(). Another alternative would be to provide
4827 // multiple instances of the PlatformEvent() for each thread. One
4828 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4829 //
4830 // * Usage:
4831 // -- Only as leaf locks
4832 // -- for short-term locking only as muxAcquire does not perform
4833 // thread state transitions.
4834 //
4835 // Alternatives:
4836 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4837 // but with parking or spin-then-park instead of pure spinning.
4838 // * Use Taura-Oyama-Yonenzawa locks.
4839 // * It's possible to construct a 1-0 lock if we encode the lockword as
4840 // (List,LockByte). Acquire will CAS the full lockword while Release
4841 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4842 // acquiring threads use timers (ParkTimed) to detect and recover from
4843 // the stranding window. Thread/Node structures must be aligned on 256-byte
4844 // boundaries by using placement-new.
4845 // * Augment MCS with advisory back-link fields maintained with CAS().
4846 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4847 // The validity of the backlinks must be ratified before we trust the value.
4848 // If the backlinks are invalid the exiting thread must back-track through the
4849 // the forward links, which are always trustworthy.
4850 // * Add a successor indication. The LockWord is currently encoded as
4851 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4852 // to provide the usual futile-wakeup optimization.
4853 // See RTStt for details.
4854 // * Consider schedctl.sc_nopreempt to cover the critical section.
4855 //
4856
4857
4858 const intptr_t LOCKBIT = 1;
4859
4860 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4861 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4862 if (w == 0) return;
4863 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4864 return;
4865 }
4866
4867 TEVENT(muxAcquire - Contention);
4868 ParkEvent * const Self = Thread::current()->_MuxEvent;
4869 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4870 for (;;) {
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 return;
4878 }
4879 }
4880
4881 Self->reset();
4882 Self->OnList = intptr_t(Lock);
4883 // The following fence() isn't _strictly necessary as the subsequent
4884 // CAS() both serializes execution and ratifies the fetched *Lock value.
4885 OrderAccess::fence();
4886 for (;;) {
4887 w = *Lock;
4888 if ((w & LOCKBIT) == 0) {
4889 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4890 Self->OnList = 0; // hygiene - allows stronger asserts
4891 return;
4892 }
4893 continue; // Interference -- *Lock changed -- Just retry
4894 }
4895 assert(w & LOCKBIT, "invariant");
4896 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4897 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4898 }
4899
4900 while (Self->OnList != 0) {
4901 Self->park();
4902 }
4903 }
4904 }
4905
4906 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4907 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4908 if (w == 0) return;
4909 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4910 return;
4911 }
4912
4913 TEVENT(muxAcquire - Contention);
4914 ParkEvent * ReleaseAfter = NULL;
4915 if (ev == NULL) {
4916 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4917 }
4918 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4919 for (;;) {
4920 guarantee(ev->OnList == 0, "invariant");
4921 int its = (os::is_MP() ? 100 : 0) + 1;
4922
4923 // Optional spin phase: spin-then-park strategy
4924 while (--its >= 0) {
4925 w = *Lock;
4926 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4927 if (ReleaseAfter != NULL) {
4928 ParkEvent::Release(ReleaseAfter);
4929 }
4930 return;
4931 }
4932 }
4933
4934 ev->reset();
4935 ev->OnList = intptr_t(Lock);
4936 // The following fence() isn't _strictly necessary as the subsequent
4937 // CAS() both serializes execution and ratifies the fetched *Lock value.
4938 OrderAccess::fence();
4939 for (;;) {
4940 w = *Lock;
4941 if ((w & LOCKBIT) == 0) {
4942 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4943 ev->OnList = 0;
4944 // We call ::Release while holding the outer lock, thus
4945 // artificially lengthening the critical section.
4946 // Consider deferring the ::Release() until the subsequent unlock(),
4947 // after we've dropped the outer lock.
4948 if (ReleaseAfter != NULL) {
4949 ParkEvent::Release(ReleaseAfter);
4950 }
4951 return;
4952 }
4953 continue; // Interference -- *Lock changed -- Just retry
4954 }
4955 assert(w & LOCKBIT, "invariant");
4956 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4957 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4958 }
4959
4960 while (ev->OnList != 0) {
4961 ev->park();
4962 }
4963 }
4964 }
4965
4966 // Release() must extract a successor from the list and then wake that thread.
4967 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4968 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4969 // Release() would :
4970 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4971 // (B) Extract a successor from the private list "in-hand"
4972 // (C) attempt to CAS() the residual back into *Lock over null.
4973 // If there were any newly arrived threads and the CAS() would fail.
4974 // In that case Release() would detach the RATs, re-merge the list in-hand
4975 // with the RATs and repeat as needed. Alternately, Release() might
4976 // detach and extract a successor, but then pass the residual list to the wakee.
4977 // The wakee would be responsible for reattaching and remerging before it
4978 // competed for the lock.
4979 //
4980 // Both "pop" and DMR are immune from ABA corruption -- there can be
4981 // multiple concurrent pushers, but only one popper or detacher.
4982 // This implementation pops from the head of the list. This is unfair,
4983 // but tends to provide excellent throughput as hot threads remain hot.
4984 // (We wake recently run threads first).
4985 //
4986 // All paths through muxRelease() will execute a CAS.
4987 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4988 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4989 // executed within the critical section are complete and globally visible before the
4990 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4991 void Thread::muxRelease(volatile intptr_t * Lock) {
4992 for (;;) {
4993 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
4994 assert(w & LOCKBIT, "invariant");
4995 if (w == LOCKBIT) return;
4996 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4997 assert(List != NULL, "invariant");
4998 assert(List->OnList == intptr_t(Lock), "invariant");
4999 ParkEvent * const nxt = List->ListNext;
5000 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5001
5002 // The following CAS() releases the lock and pops the head element.
5003 // The CAS() also ratifies the previously fetched lock-word value.
5004 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
5005 continue;
5006 }
5007 List->OnList = 0;
5008 OrderAccess::fence();
5009 List->unpark();
5010 return;
5011 }
5012 }
5013
5014 void Thread::pick_next_sample(size_t overflowed_bytes) {
5015 HeapMonitoring::pick_next_sample(&_bytes_until_sample);
5016
5017 // Try to correct sample size by removing extra space from last allocation.
5018 if (overflowed_bytes > 0 && _bytes_until_sample > overflowed_bytes) {
5019 _bytes_until_sample -= overflowed_bytes;
5020 }
5021 }
5022
5023 void Thread::check_for_sampling(HeapWord* ptr, size_t allocation_size, size_t bytes_since_allocation) {
5024 oopDesc* oop = reinterpret_cast<oopDesc*>(ptr);
5025 size_t total_allocated_bytes = bytes_since_allocation + allocation_size;
5026
5027 // If not yet time for a sample, skip it.
5028 if (total_allocated_bytes < _bytes_until_sample) {
5029 _bytes_until_sample -= total_allocated_bytes;
5030 return;
5031 }
5032
5033 HeapMonitoring::object_alloc_do_sample(this, oop, allocation_size);
5034
5035 size_t overflow_bytes = total_allocated_bytes - _bytes_until_sample;
5036 pick_next_sample(overflow_bytes);
5037 }
5038
5039 size_t Thread::bytes_until_sample() {
5040 if (!_bytes_until_sample) {
5041 pick_next_sample();
5042 }
5043
5044 assert(_bytes_until_sample != 0, "Sampling size should never be 0");
5045 return _bytes_until_sample;
5046 }
5047
5048 void Threads::verify() {
5049 ALL_JAVA_THREADS(p) {
5050 p->verify();
5051 }
5052 VMThread* thread = VMThread::vm_thread();
5053 if (thread != NULL) thread->verify();
5054 }
5055