1 /*
2 * Copyright (c) 1997, 2023, 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 "classfile/classLoaderDataGraph.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "code/codeCache.hpp"
29 #include "compiler/compileBroker.hpp"
30 #include "gc/shared/collectedHeap.hpp"
31 #include "gc/shared/isGCActiveMark.hpp"
32 #include "logging/log.hpp"
33 #include "logging/logStream.hpp"
34 #include "logging/logConfiguration.hpp"
35 #include "memory/heapInspection.hpp"
36 #include "memory/metaspace/metaspaceReporter.hpp"
37 #include "memory/resourceArea.hpp"
38 #include "memory/universe.hpp"
39 #include "oops/symbol.hpp"
40 #include "runtime/arguments.hpp"
41 #include "runtime/deoptimization.hpp"
42 #include "runtime/frame.inline.hpp"
43 #include "runtime/interfaceSupport.inline.hpp"
44 #include "runtime/javaThread.inline.hpp"
45 #include "runtime/jniHandles.hpp"
46 #include "runtime/objectMonitor.inline.hpp"
47 #include "runtime/stackFrameStream.inline.hpp"
48 #include "runtime/synchronizer.hpp"
49 #include "runtime/threads.hpp"
50 #include "runtime/threadSMR.inline.hpp"
51 #include "runtime/vmOperations.hpp"
52 #include "services/threadService.hpp"
53 #include "utilities/ticks.hpp"
54
55 #define VM_OP_NAME_INITIALIZE(name) #name,
56
57 const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \
58 { VM_OPS_DO(VM_OP_NAME_INITIALIZE) };
59
60 void VM_Operation::set_calling_thread(Thread* thread) {
61 _calling_thread = thread;
62 }
63
64 void VM_Operation::evaluate() {
65 ResourceMark rm;
66 LogTarget(Debug, vmoperation) lt;
67 if (lt.is_enabled()) {
68 LogStream ls(lt);
69 ls.print("begin ");
70 print_on_error(&ls);
71 ls.cr();
72 }
73 doit();
74 if (lt.is_enabled()) {
75 LogStream ls(lt);
76 ls.print("end ");
77 print_on_error(&ls);
78 ls.cr();
79 }
80 }
81
82 // Called by fatal error handler.
83 void VM_Operation::print_on_error(outputStream* st) const {
84 st->print("VM_Operation (" PTR_FORMAT "): ", p2i(this));
85 st->print("%s", name());
86
87 st->print(", mode: %s", evaluate_at_safepoint() ? "safepoint" : "no safepoint");
88
89 if (calling_thread()) {
90 st->print(", requested by thread " PTR_FORMAT, p2i(calling_thread()));
91 }
92 }
93
94 void VM_ClearICs::doit() {
95 if (_preserve_static_stubs) {
96 CodeCache::cleanup_inline_caches_whitebox();
97 } else {
98 CodeCache::clear_inline_caches();
99 }
100 }
101
102 void VM_CleanClassLoaderDataMetaspaces::doit() {
103 ClassLoaderDataGraph::walk_metadata_and_clean_metaspaces();
104 }
105
106 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) {
107 _thread = thread;
108 _id = id;
109 _reason = reason;
110 }
111
112
113 void VM_DeoptimizeFrame::doit() {
114 assert(_reason > Deoptimization::Reason_none && _reason < Deoptimization::Reason_LIMIT, "invalid deopt reason");
115 Deoptimization::deoptimize_frame_internal(_thread, _id, (Deoptimization::DeoptReason)_reason);
116 }
117
118
119 #ifndef PRODUCT
120
121 void VM_DeoptimizeAll::doit() {
122 JavaThreadIteratorWithHandle jtiwh;
123 // deoptimize all java threads in the system
124 if (DeoptimizeALot) {
125 for (; JavaThread *thread = jtiwh.next(); ) {
126 if (thread->has_last_Java_frame()) {
127 thread->deoptimize();
128 }
129 }
130 } else if (DeoptimizeRandom) {
131
132 // Deoptimize some selected threads and frames
133 int tnum = os::random() & 0x3;
134 int fnum = os::random() & 0x3;
135 int tcount = 0;
136 for (; JavaThread *thread = jtiwh.next(); ) {
137 if (thread->has_last_Java_frame()) {
138 if (tcount++ == tnum) {
139 tcount = 0;
140 int fcount = 0;
141 // Deoptimize some selected frames.
142 for(StackFrameStream fst(thread, false /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
143 if (fst.current()->can_be_deoptimized()) {
144 if (fcount++ == fnum) {
145 fcount = 0;
146 Deoptimization::deoptimize(thread, *fst.current());
147 }
148 }
149 }
150 }
151 }
152 }
153 }
154 }
155
156
157 void VM_ZombieAll::doit() {
158 JavaThread::cast(calling_thread())->make_zombies();
159 }
160
161 #endif // !PRODUCT
162
163 bool VM_PrintThreads::doit_prologue() {
164 // Get Heap_lock if concurrent locks will be dumped
165 if (_print_concurrent_locks) {
166 Heap_lock->lock();
167 }
168 return true;
169 }
170
171 void VM_PrintThreads::doit() {
172 Threads::print_on(_out, true, false, _print_concurrent_locks, _print_extended_info);
173 if (_print_jni_handle_info) {
174 JNIHandles::print_on(_out);
175 }
176 }
177
178 void VM_PrintThreads::doit_epilogue() {
179 if (_print_concurrent_locks) {
180 // Release Heap_lock
181 Heap_lock->unlock();
182 }
183 }
184
185 void VM_PrintMetadata::doit() {
186 metaspace::MetaspaceReporter::print_report(_out, _scale, _flags);
187 }
188
189 VM_FindDeadlocks::~VM_FindDeadlocks() {
190 if (_deadlocks != nullptr) {
191 DeadlockCycle* cycle = _deadlocks;
192 while (cycle != nullptr) {
193 DeadlockCycle* d = cycle;
194 cycle = cycle->next();
195 delete d;
196 }
197 }
198 }
199
200 void VM_FindDeadlocks::doit() {
201 // Update the hazard ptr in the originating thread to the current
202 // list of threads. This VM operation needs the current list of
203 // threads for proper deadlock detection and those are the
204 // JavaThreads we need to be protected when we return info to the
205 // originating thread.
206 _setter.set();
207
208 _deadlocks = ThreadService::find_deadlocks_at_safepoint(_setter.list(), _concurrent_locks);
209 if (_out != nullptr) {
210 int num_deadlocks = 0;
211 for (DeadlockCycle* cycle = _deadlocks; cycle != nullptr; cycle = cycle->next()) {
212 num_deadlocks++;
213 cycle->print_on_with(_setter.list(), _out);
214 }
215
216 if (num_deadlocks == 1) {
217 _out->print_cr("\nFound 1 deadlock.\n");
218 _out->flush();
219 } else if (num_deadlocks > 1) {
220 _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
221 _out->flush();
222 }
223 }
224 }
225
226 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
227 int max_depth,
228 bool with_locked_monitors,
229 bool with_locked_synchronizers) {
230 _result = result;
231 _num_threads = 0; // 0 indicates all threads
232 _threads = nullptr;
233 _max_depth = max_depth;
234 _with_locked_monitors = with_locked_monitors;
235 _with_locked_synchronizers = with_locked_synchronizers;
236 }
237
238 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
239 GrowableArray<instanceHandle>* threads,
240 int num_threads,
241 int max_depth,
242 bool with_locked_monitors,
243 bool with_locked_synchronizers) {
244 _result = result;
245 _num_threads = num_threads;
246 _threads = threads;
247 _max_depth = max_depth;
248 _with_locked_monitors = with_locked_monitors;
249 _with_locked_synchronizers = with_locked_synchronizers;
250 }
251
252 bool VM_ThreadDump::doit_prologue() {
253 if (_with_locked_synchronizers) {
254 // Acquire Heap_lock to dump concurrent locks
255 Heap_lock->lock();
256 }
257
258 return true;
259 }
260
261 void VM_ThreadDump::doit_epilogue() {
262 if (_with_locked_synchronizers) {
263 // Release Heap_lock
264 Heap_lock->unlock();
265 }
266 }
267
268 // Hash table of void* to a list of ObjectMonitor* owned by the JavaThread.
269 // The JavaThread's owner key is either a JavaThread* or a stack lock
270 // address in the JavaThread so we use "void*".
271 //
272 class ObjectMonitorsDump : public MonitorClosure, public ObjectMonitorsView {
273 private:
274 static unsigned int ptr_hash(void* const& s1) {
275 // 2654435761 = 2^32 * Phi (golden ratio)
276 return (unsigned int)(((uint32_t)(uintptr_t)s1) * 2654435761u);
277 }
278
279 private:
280 class ObjectMonitorLinkedList :
281 public LinkedListImpl<ObjectMonitor*,
282 AnyObj::C_HEAP, mtThread,
283 AllocFailStrategy::RETURN_NULL> {};
284
285 // ResourceHashtable SIZE is specified at compile time so we
286 // use 1031 which is the first prime after 1024.
287 typedef ResourceHashtable<void*, ObjectMonitorLinkedList*, 1031, AnyObj::C_HEAP, mtThread,
288 &ObjectMonitorsDump::ptr_hash> PtrTable;
289 PtrTable* _ptrs;
290 size_t _key_count;
291 size_t _om_count;
292
293 void add_list(void* key, ObjectMonitorLinkedList* list) {
294 _ptrs->put(key, list);
295 _key_count++;
296 }
297
298 ObjectMonitorLinkedList* get_list(void* key) {
299 ObjectMonitorLinkedList** listpp = _ptrs->get(key);
300 return (listpp == nullptr) ? nullptr : *listpp;
301 }
302
303 void add(ObjectMonitor* monitor) {
304 void* key = monitor->owner();
305
306 ObjectMonitorLinkedList* list = get_list(key);
307 if (list == nullptr) {
308 // Create new list and add it to the hash table:
309 list = new (mtThread) ObjectMonitorLinkedList;
310 _ptrs->put(key, list);
311 _key_count++;
312 }
313
314 assert(list->find(monitor) == nullptr, "Should not contain duplicates");
315 list->add(monitor); // Add the ObjectMonitor to the list.
316 _om_count++;
317 }
318
319 public:
320 // ResourceHashtable is passed to various functions and populated in
321 // different places so we allocate it using C_HEAP to make it immune
322 // from any ResourceMarks that happen to be in the code paths.
323 ObjectMonitorsDump() : _ptrs(new (mtThread) PtrTable), _key_count(0), _om_count(0) {}
324
325 ~ObjectMonitorsDump() {
326 class CleanupObjectMonitorsDump: StackObj {
327 public:
328 bool do_entry(void*& key, ObjectMonitorLinkedList*& list) {
329 list->clear(); // clear the LinkListNodes
330 delete list; // then delete the LinkedList
331 return true;
332 }
333 } cleanup;
334
335 _ptrs->unlink(&cleanup); // cleanup the LinkedLists
336 delete _ptrs; // then delete the hash table
337 }
338
339 // Implements MonitorClosure used to collect all owned monitors in the system
340 void do_monitor(ObjectMonitor* monitor) override {
341 assert(monitor->has_owner(), "Expects only owned monitors");
342
343 if (monitor->is_owner_anonymous()) {
344 // There's no need to collect anonymous owned monitors
345 // because the caller of this code is only interested
346 // in JNI owned monitors.
347 return;
348 }
349
350 if (monitor->object_peek() == nullptr) {
351 // JNI code doesn't necessarily keep the monitor object
352 // alive. Filter out monitors with dead objects.
353 return;
354 }
355
356 add(monitor);
357 }
358
359 // Implements the ObjectMonitorsView interface
360 void visit(MonitorClosure* closure, JavaThread* thread) override {
361 ObjectMonitorLinkedList* list = get_list(thread);
362 LinkedListIterator<ObjectMonitor*> iter(list != nullptr ? list->head() : nullptr);
363 while (!iter.is_empty()) {
364 ObjectMonitor* monitor = *iter.next();
365 closure->do_monitor(monitor);
366 }
367 }
368
369 size_t key_count() { return _key_count; }
370 size_t om_count() { return _om_count; }
371 };
372
373 void VM_ThreadDump::doit() {
374 ResourceMark rm;
375
376 // Set the hazard ptr in the originating thread to protect the
377 // current list of threads. This VM operation needs the current list
378 // of threads for a proper dump and those are the JavaThreads we need
379 // to be protected when we return info to the originating thread.
380 _result->set_t_list();
381
382 ConcurrentLocksDump concurrent_locks(true);
383 if (_with_locked_synchronizers) {
384 concurrent_locks.dump_at_safepoint();
385 }
386
387 ObjectMonitorsDump object_monitors;
388 if (_with_locked_monitors) {
389 // Gather information about owned monitors.
390 ObjectSynchronizer::owned_monitors_iterate(&object_monitors);
391
392 // If there are many object monitors in the system then the above iteration
393 // can start to take time. Be friendly to following thread dumps by telling
394 // the MonitorDeflationThread to deflate monitors.
395 //
396 // This is trying to be somewhat backwards compatible with the previous
397 // implementation, which performed monitor deflation right here. We might
398 // want to reconsider the need to trigger monitor deflation from the thread
399 // dumping and instead maybe tweak the deflation heuristics.
400 ObjectSynchronizer::request_deflate_idle_monitors();
401 }
402
403 if (_num_threads == 0) {
404 // Snapshot all live threads
405
406 for (uint i = 0; i < _result->t_list()->length(); i++) {
407 JavaThread* jt = _result->t_list()->thread_at(i);
408 if (jt->is_exiting() ||
409 jt->is_hidden_from_external_view()) {
410 // skip terminating threads and hidden threads
411 continue;
412 }
413 ThreadConcurrentLocks* tcl = nullptr;
414 if (_with_locked_synchronizers) {
415 tcl = concurrent_locks.thread_concurrent_locks(jt);
416 }
417 snapshot_thread(jt, tcl, &object_monitors);
418 }
419 } else {
420 // Snapshot threads in the given _threads array
421 // A dummy snapshot is created if a thread doesn't exist
422
423 for (int i = 0; i < _num_threads; i++) {
424 instanceHandle th = _threads->at(i);
425 if (th() == nullptr) {
426 // skip if the thread doesn't exist
427 // Add a dummy snapshot
428 _result->add_thread_snapshot();
429 continue;
430 }
431
432 // Dump thread stack only if the thread is alive and not exiting
433 // and not VM internal thread.
434 JavaThread* jt = java_lang_Thread::thread(th());
435 if (jt != nullptr && !_result->t_list()->includes(jt)) {
436 // _threads[i] doesn't refer to a valid JavaThread; this check
437 // is primarily for JVM_DumpThreads() which doesn't have a good
438 // way to validate the _threads array.
439 jt = nullptr;
440 }
441 if (jt == nullptr || /* thread not alive */
442 jt->is_exiting() ||
443 jt->is_hidden_from_external_view()) {
444 // add a null snapshot if skipped
445 _result->add_thread_snapshot();
446 continue;
447 }
448 ThreadConcurrentLocks* tcl = nullptr;
449 if (_with_locked_synchronizers) {
450 tcl = concurrent_locks.thread_concurrent_locks(jt);
451 }
452 snapshot_thread(jt, tcl, &object_monitors);
453 }
454 }
455 }
456
457 void VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl,
458 ObjectMonitorsView* monitors) {
459 ThreadSnapshot* snapshot = _result->add_thread_snapshot(java_thread);
460 snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors, monitors, false);
461 snapshot->set_concurrent_locks(tcl);
462 }
463
464 volatile bool VM_Exit::_vm_exited = false;
465 Thread * volatile VM_Exit::_shutdown_thread = nullptr;
466
467 int VM_Exit::set_vm_exited() {
468
469 Thread * thr_cur = Thread::current();
470
471 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
472
473 int num_active = 0;
474
475 _shutdown_thread = thr_cur;
476 _vm_exited = true; // global flag
477 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thr = jtiwh.next(); ) {
478 if (thr != thr_cur && thr->thread_state() == _thread_in_native) {
479 ++num_active;
480 thr->set_terminated(JavaThread::_vm_exited); // per-thread flag
481 }
482 }
483
484 return num_active;
485 }
486
487 int VM_Exit::wait_for_threads_in_native_to_block() {
488 // VM exits at safepoint. This function must be called at the final safepoint
489 // to wait for threads in _thread_in_native state to be quiescent.
490 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
491
492 Thread * thr_cur = Thread::current();
493 Monitor timer(Mutex::nosafepoint, "VM_ExitTimer_lock");
494
495 // Compiler threads need longer wait because they can access VM data directly
496 // while in native. If they are active and some structures being used are
497 // deleted by the shutdown sequence, they will crash. On the other hand, user
498 // threads must go through native=>Java/VM transitions first to access VM
499 // data, and they will be stopped during state transition. In theory, we
500 // don't have to wait for user threads to be quiescent, but it's always
501 // better to terminate VM when current thread is the only active thread, so
502 // wait for user threads too. Numbers are in 10 milliseconds.
503 int wait_time_per_attempt = 10; // in milliseconds
504 int max_wait_attempts_user_thread = UserThreadWaitAttemptsAtExit;
505 int max_wait_attempts_compiler_thread = 1000; // at least 10 seconds
506
507 int attempts = 0;
508 JavaThreadIteratorWithHandle jtiwh;
509 while (true) {
510 int num_active = 0;
511 int num_active_compiler_thread = 0;
512
513 jtiwh.rewind();
514 for (; JavaThread *thr = jtiwh.next(); ) {
515 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
516 num_active++;
517 if (thr->is_Compiler_thread()) {
518 #if INCLUDE_JVMCI
519 CompilerThread* ct = (CompilerThread*) thr;
520 if (ct->compiler() == nullptr || !ct->compiler()->is_jvmci()) {
521 num_active_compiler_thread++;
522 } else {
523 // A JVMCI compiler thread never accesses VM data structures
524 // while in _thread_in_native state so there's no need to wait
525 // for it and potentially add a 300 millisecond delay to VM
526 // shutdown.
527 num_active--;
528 }
529 #else
530 num_active_compiler_thread++;
531 #endif
532 }
533 }
534 }
535
536 if (num_active == 0) {
537 return 0;
538 } else if (attempts >= max_wait_attempts_compiler_thread) {
539 return num_active;
540 } else if (num_active_compiler_thread == 0 &&
541 attempts >= max_wait_attempts_user_thread) {
542 return num_active;
543 }
544
545 attempts++;
546
547 MonitorLocker ml(&timer, Mutex::_no_safepoint_check_flag);
548 ml.wait(wait_time_per_attempt);
549 }
550 }
551
552 void VM_Exit::doit() {
553
554 if (VerifyBeforeExit) {
555 HandleMark hm(VMThread::vm_thread());
556 // Among other things, this ensures that Eden top is correct.
557 Universe::heap()->prepare_for_verify();
558 // Silent verification so as not to pollute normal output,
559 // unless we really asked for it.
560 Universe::verify();
561 }
562
563 CompileBroker::set_should_block();
564
565 // Wait for a short period for threads in native to block. Any thread
566 // still executing native code after the wait will be stopped at
567 // native==>Java/VM barriers.
568 // Among 16276 JCK tests, 94% of them come here without any threads still
569 // running in native; the other 6% are quiescent within 250ms (Ultra 80).
570 wait_for_threads_in_native_to_block();
571
572 set_vm_exited();
573
574 // The ObjectMonitor subsystem uses perf counters so do this before
575 // we call exit_globals() so we don't run afoul of perfMemory_exit().
576 ObjectSynchronizer::do_final_audit_and_print_stats();
577
578 // We'd like to call IdealGraphPrinter::clean_up() to finalize the
579 // XML logging, but we can't safely do that here. The logic to make
580 // XML termination logging safe is tied to the termination of the
581 // VMThread, and it doesn't terminate on this exit path. See 8222534.
582
583 // cleanup globals resources before exiting. exit_globals() currently
584 // cleans up outputStream resources and PerfMemory resources.
585 exit_globals();
586
587 LogConfiguration::finalize();
588
589 // Check for exit hook
590 exit_hook_t exit_hook = Arguments::exit_hook();
591 if (exit_hook != nullptr) {
592 // exit hook should exit.
593 exit_hook(_exit_code);
594 // ... but if it didn't, we must do it here
595 vm_direct_exit(_exit_code);
596 } else {
597 vm_direct_exit(_exit_code);
598 }
599 }
600
601
602 void VM_Exit::wait_if_vm_exited() {
603 if (_vm_exited &&
604 Thread::current_or_null() != _shutdown_thread) {
605 // _vm_exited is set at safepoint, and the Threads_lock is never released
606 // so we will block here until the process dies.
607 Threads_lock->lock();
608 ShouldNotReachHere();
609 }
610 }
611
612 void VM_PrintCompileQueue::doit() {
613 CompileBroker::print_compile_queues(_out);
614 }
615
616 #if INCLUDE_SERVICES
617 void VM_PrintClassHierarchy::doit() {
618 KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname);
619 }
620 #endif