1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/symbolTable.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "code/codeCache.hpp"
29 #include "compiler/compileBroker.hpp"
30 #include "gc/shared/isGCActiveMark.hpp"
31 #include "logging/log.hpp"
32 #include "logging/logStream.hpp"
33 #include "memory/heapInspection.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "oops/symbol.hpp"
36 #include "runtime/arguments.hpp"
37 #include "runtime/deoptimization.hpp"
38 #include "runtime/frame.inline.hpp"
39 #include "runtime/interfaceSupport.inline.hpp"
40 #include "runtime/sweeper.hpp"
41 #include "runtime/thread.inline.hpp"
42 #include "runtime/threadSMR.inline.hpp"
43 #include "runtime/vm_operations.hpp"
44 #include "services/threadService.hpp"
45 #include "trace/tracing.hpp"
46
47 #define VM_OP_NAME_INITIALIZE(name) #name,
48
49 const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \
50 { VM_OPS_DO(VM_OP_NAME_INITIALIZE) };
51
52 void VM_Operation::set_calling_thread(Thread* thread, ThreadPriority priority) {
53 _calling_thread = thread;
54 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
55 _priority = priority;
56 }
57
58
59 void VM_Operation::evaluate() {
60 ResourceMark rm;
61 LogTarget(Debug, vmoperation) lt;
62 if (lt.is_enabled()) {
63 LogStream ls(lt);
64 ls.print("begin ");
65 print_on_error(&ls);
66 ls.cr();
67 }
68 doit();
69 if (lt.is_enabled()) {
70 LogStream ls(lt);
71 ls.print("end ");
72 print_on_error(&ls);
73 ls.cr();
74 }
75 }
76
77 const char* VM_Operation::mode_to_string(Mode mode) {
78 switch(mode) {
79 case _safepoint : return "safepoint";
80 case _no_safepoint : return "no safepoint";
81 case _concurrent : return "concurrent";
82 case _async_safepoint: return "async safepoint";
83 default : return "unknown";
84 }
85 }
86 // Called by fatal error handler.
87 void VM_Operation::print_on_error(outputStream* st) const {
88 st->print("VM_Operation (" PTR_FORMAT "): ", p2i(this));
89 st->print("%s", name());
90
91 const char* mode = mode_to_string(evaluation_mode());
92 st->print(", mode: %s", mode);
93
94 if (calling_thread()) {
95 st->print(", requested by thread " PTR_FORMAT, p2i(calling_thread()));
96 }
97 }
98
99 void VM_ThreadStop::doit() {
100 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
101 ThreadsListHandle tlh;
102 JavaThread* target = java_lang_Thread::thread(target_thread());
103 // Note that this now allows multiple ThreadDeath exceptions to be
104 // thrown at a thread.
105 if (target != NULL && (!EnableThreadSMRExtraValidityChecks || tlh.includes(target))) {
106 // The target thread has run and has not exited yet.
107 target->send_thread_stop(throwable());
108 }
109 }
110
111 void VM_ClearICs::doit() {
112 if (_preserve_static_stubs) {
113 CodeCache::cleanup_inline_caches();
114 } else {
115 CodeCache::clear_inline_caches();
116 }
117 }
118
119 void VM_Deoptimize::doit() {
120 // We do not want any GCs to happen while we are in the middle of this VM operation
121 ResourceMark rm;
122 DeoptimizationMarker dm;
123
124 // Deoptimize all activations depending on marked nmethods
125 Deoptimization::deoptimize_dependents();
126
127 // Make the dependent methods not entrant
128 CodeCache::make_marked_nmethods_not_entrant();
129 }
130
131 void VM_MarkActiveNMethods::doit() {
132 NMethodSweeper::mark_active_nmethods();
133 }
134
135 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) {
136 _thread = thread;
137 _id = id;
138 _reason = reason;
139 }
140
141
142 void VM_DeoptimizeFrame::doit() {
143 assert(_reason > Deoptimization::Reason_none && _reason < Deoptimization::Reason_LIMIT, "invalid deopt reason");
144 Deoptimization::deoptimize_frame_internal(_thread, _id, (Deoptimization::DeoptReason)_reason);
145 }
146
147
148 #ifndef PRODUCT
149
150 void VM_DeoptimizeAll::doit() {
151 DeoptimizationMarker dm;
152 JavaThreadIteratorWithHandle jtiwh;
153 // deoptimize all java threads in the system
154 if (DeoptimizeALot) {
155 for (; JavaThread *thread = jtiwh.next(); ) {
156 if (thread->has_last_Java_frame()) {
157 thread->deoptimize();
158 }
159 }
160 } else if (DeoptimizeRandom) {
161
162 // Deoptimize some selected threads and frames
163 int tnum = os::random() & 0x3;
164 int fnum = os::random() & 0x3;
165 int tcount = 0;
166 for (; JavaThread *thread = jtiwh.next(); ) {
167 if (thread->has_last_Java_frame()) {
168 if (tcount++ == tnum) {
169 tcount = 0;
170 int fcount = 0;
171 // Deoptimize some selected frames.
172 // Biased llocking wants a updated register map
173 for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {
174 if (fst.current()->can_be_deoptimized()) {
175 if (fcount++ == fnum) {
176 fcount = 0;
177 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());
178 }
179 }
180 }
181 }
182 }
183 }
184 }
185 }
186
187
188 void VM_ZombieAll::doit() {
189 JavaThread *thread = (JavaThread *)calling_thread();
190 assert(thread->is_Java_thread(), "must be a Java thread");
191 thread->make_zombies();
192 }
193
194 #endif // !PRODUCT
195
196 void VM_UnlinkSymbols::doit() {
197 JavaThread *thread = (JavaThread *)calling_thread();
198 assert(thread->is_Java_thread(), "must be a Java thread");
199 SymbolTable::unlink();
200 }
201
202 void VM_Verify::doit() {
203 Universe::heap()->prepare_for_verify();
204 Universe::verify();
205 }
206
207 bool VM_PrintThreads::doit_prologue() {
208 // Make sure AbstractOwnableSynchronizer is loaded
209 JavaThread* jt = JavaThread::current();
210 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt);
211 if (jt->has_pending_exception()) {
212 return false;
213 }
214
215 // Get Heap_lock if concurrent locks will be dumped
216 if (_print_concurrent_locks) {
217 Heap_lock->lock();
218 }
219 return true;
220 }
221
222 void VM_PrintThreads::doit() {
223 Threads::print_on(_out, true, false, _print_concurrent_locks);
224 }
225
226 void VM_PrintThreads::doit_epilogue() {
227 if (_print_concurrent_locks) {
228 // Release Heap_lock
229 Heap_lock->unlock();
230 }
231 }
232
233 void VM_PrintJNI::doit() {
234 JNIHandles::print_on(_out);
235 }
236
237 void VM_PrintMetadata::doit() {
238 MetaspaceUtils::print_report(_out, _scale, _flags);
239 }
240
241 VM_FindDeadlocks::~VM_FindDeadlocks() {
242 if (_deadlocks != NULL) {
243 DeadlockCycle* cycle = _deadlocks;
244 while (cycle != NULL) {
245 DeadlockCycle* d = cycle;
246 cycle = cycle->next();
247 delete d;
248 }
249 }
250 }
251
252 bool VM_FindDeadlocks::doit_prologue() {
253 if (_concurrent_locks) {
254 // Make sure AbstractOwnableSynchronizer is loaded
255 JavaThread* jt = JavaThread::current();
256 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt);
257 if (jt->has_pending_exception()) {
258 return false;
259 }
260 }
261
262 return true;
263 }
264
265 void VM_FindDeadlocks::doit() {
266 // Update the hazard ptr in the originating thread to the current
267 // list of threads. This VM operation needs the current list of
268 // threads for proper deadlock detection and those are the
269 // JavaThreads we need to be protected when we return info to the
270 // originating thread.
271 _setter.set();
272
273 _deadlocks = ThreadService::find_deadlocks_at_safepoint(_setter.list(), _concurrent_locks);
274 if (_out != NULL) {
275 int num_deadlocks = 0;
276 for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
277 num_deadlocks++;
278 cycle->print_on_with(_setter.list(), _out);
279 }
280
281 if (num_deadlocks == 1) {
282 _out->print_cr("\nFound 1 deadlock.\n");
283 _out->flush();
284 } else if (num_deadlocks > 1) {
285 _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
286 _out->flush();
287 }
288 }
289 }
290
291 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
292 int max_depth,
293 bool with_locked_monitors,
294 bool with_locked_synchronizers) {
295 _result = result;
296 _num_threads = 0; // 0 indicates all threads
297 _threads = NULL;
298 _result = result;
299 _max_depth = max_depth;
300 _with_locked_monitors = with_locked_monitors;
301 _with_locked_synchronizers = with_locked_synchronizers;
302 }
303
304 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
305 GrowableArray<instanceHandle>* threads,
306 int num_threads,
307 int max_depth,
308 bool with_locked_monitors,
309 bool with_locked_synchronizers) {
310 _result = result;
311 _num_threads = num_threads;
312 _threads = threads;
313 _result = result;
314 _max_depth = max_depth;
315 _with_locked_monitors = with_locked_monitors;
316 _with_locked_synchronizers = with_locked_synchronizers;
317 }
318
319 bool VM_ThreadDump::doit_prologue() {
320 // Make sure AbstractOwnableSynchronizer is loaded
321 JavaThread* jt = JavaThread::current();
322 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt);
323 if (jt->has_pending_exception()) {
324 return false;
325 }
326
327 if (_with_locked_synchronizers) {
328 // Acquire Heap_lock to dump concurrent locks
329 Heap_lock->lock();
330 }
331
332 return true;
333 }
334
335 void VM_ThreadDump::doit_epilogue() {
336 if (_with_locked_synchronizers) {
337 // Release Heap_lock
338 Heap_lock->unlock();
339 }
340 }
341
342 void VM_ThreadDump::doit() {
343 ResourceMark rm;
344
345 // Set the hazard ptr in the originating thread to protect the
346 // current list of threads. This VM operation needs the current list
347 // of threads for a proper dump and those are the JavaThreads we need
348 // to be protected when we return info to the originating thread.
349 _result->set_t_list();
350
351 ConcurrentLocksDump concurrent_locks(true);
352 if (_with_locked_synchronizers) {
353 concurrent_locks.dump_at_safepoint();
354 }
355
356 if (_num_threads == 0) {
357 // Snapshot all live threads
358
359 for (uint i = 0; i < _result->t_list()->length(); i++) {
360 JavaThread* jt = _result->t_list()->thread_at(i);
361 if (jt->is_exiting() ||
362 jt->is_hidden_from_external_view()) {
363 // skip terminating threads and hidden threads
364 continue;
365 }
366 ThreadConcurrentLocks* tcl = NULL;
367 if (_with_locked_synchronizers) {
368 tcl = concurrent_locks.thread_concurrent_locks(jt);
369 }
370 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
371 _result->add_thread_snapshot(ts);
372 }
373 } else {
374 // Snapshot threads in the given _threads array
375 // A dummy snapshot is created if a thread doesn't exist
376
377 for (int i = 0; i < _num_threads; i++) {
378 instanceHandle th = _threads->at(i);
379 if (th() == NULL) {
380 // skip if the thread doesn't exist
381 // Add a dummy snapshot
382 _result->add_thread_snapshot(new ThreadSnapshot());
383 continue;
384 }
385
386 // Dump thread stack only if the thread is alive and not exiting
387 // and not VM internal thread.
388 JavaThread* jt = java_lang_Thread::thread(th());
389 if (jt != NULL && !_result->t_list()->includes(jt)) {
390 // _threads[i] doesn't refer to a valid JavaThread; this check
391 // is primarily for JVM_DumpThreads() which doesn't have a good
392 // way to validate the _threads array.
393 jt = NULL;
394 }
395 if (jt == NULL || /* thread not alive */
396 jt->is_exiting() ||
397 jt->is_hidden_from_external_view()) {
398 // add a NULL snapshot if skipped
399 _result->add_thread_snapshot(new ThreadSnapshot());
400 continue;
401 }
402 ThreadConcurrentLocks* tcl = NULL;
403 if (_with_locked_synchronizers) {
404 tcl = concurrent_locks.thread_concurrent_locks(jt);
405 }
406 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
407 _result->add_thread_snapshot(ts);
408 }
409 }
410 }
411
412 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
413 ThreadSnapshot* snapshot = new ThreadSnapshot(_result->t_list(), java_thread);
414 snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
415 snapshot->set_concurrent_locks(tcl);
416 return snapshot;
417 }
418
419 volatile bool VM_Exit::_vm_exited = false;
420 Thread * volatile VM_Exit::_shutdown_thread = NULL;
421
422 int VM_Exit::set_vm_exited() {
423
424 Thread * thr_cur = Thread::current();
425
426 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
427
428 int num_active = 0;
429
430 _shutdown_thread = thr_cur;
431 _vm_exited = true; // global flag
432 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thr = jtiwh.next(); ) {
433 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
434 ++num_active;
435 thr->set_terminated(JavaThread::_vm_exited); // per-thread flag
436 }
437 }
438
439 return num_active;
440 }
441
442 int VM_Exit::wait_for_threads_in_native_to_block() {
443 // VM exits at safepoint. This function must be called at the final safepoint
444 // to wait for threads in _thread_in_native state to be quiescent.
445 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
446
447 Thread * thr_cur = Thread::current();
448 Monitor timer(Mutex::leaf, "VM_Exit timer", true,
449 Monitor::_safepoint_check_never);
450
451 // Compiler threads need longer wait because they can access VM data directly
452 // while in native. If they are active and some structures being used are
453 // deleted by the shutdown sequence, they will crash. On the other hand, user
454 // threads must go through native=>Java/VM transitions first to access VM
455 // data, and they will be stopped during state transition. In theory, we
456 // don't have to wait for user threads to be quiescent, but it's always
457 // better to terminate VM when current thread is the only active thread, so
458 // wait for user threads too. Numbers are in 10 milliseconds.
459 int max_wait_user_thread = 30; // at least 300 milliseconds
460 int max_wait_compiler_thread = 1000; // at least 10 seconds
461
462 int max_wait = max_wait_compiler_thread;
463
464 int attempts = 0;
465 JavaThreadIteratorWithHandle jtiwh;
466 while (true) {
467 int num_active = 0;
468 int num_active_compiler_thread = 0;
469
470 jtiwh.rewind();
471 for (; JavaThread *thr = jtiwh.next(); ) {
472 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
473 num_active++;
474 if (thr->is_Compiler_thread()) {
475 num_active_compiler_thread++;
476 }
477 }
478 }
479
480 if (num_active == 0) {
481 return 0;
482 } else if (attempts > max_wait) {
483 return num_active;
484 } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
485 return num_active;
486 }
487
488 attempts++;
489
490 MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag);
491 timer.wait(Mutex::_no_safepoint_check_flag, 10);
492 }
493 }
494
495 void VM_Exit::doit() {
496 CompileBroker::set_should_block();
497
498 // Wait for a short period for threads in native to block. Any thread
499 // still executing native code after the wait will be stopped at
500 // native==>Java/VM barriers.
501 // Among 16276 JCK tests, 94% of them come here without any threads still
502 // running in native; the other 6% are quiescent within 250ms (Ultra 80).
503 wait_for_threads_in_native_to_block();
504
505 set_vm_exited();
506
507 // cleanup globals resources before exiting. exit_globals() currently
508 // cleans up outputStream resources and PerfMemory resources.
509 exit_globals();
510
511 // Check for exit hook
512 exit_hook_t exit_hook = Arguments::exit_hook();
513 if (exit_hook != NULL) {
514 // exit hook should exit.
515 exit_hook(_exit_code);
516 // ... but if it didn't, we must do it here
517 vm_direct_exit(_exit_code);
518 } else {
519 vm_direct_exit(_exit_code);
520 }
521 }
522
523
524 void VM_Exit::wait_if_vm_exited() {
525 if (_vm_exited &&
526 Thread::current_or_null() != _shutdown_thread) {
527 // _vm_exited is set at safepoint, and the Threads_lock is never released
528 // we will block here until the process dies
529 Threads_lock->lock_without_safepoint_check();
530 ShouldNotReachHere();
531 }
532 }
533
534 void VM_PrintCompileQueue::doit() {
535 CompileBroker::print_compile_queues(_out);
536 }
537
538 #if INCLUDE_SERVICES
539 void VM_PrintClassHierarchy::doit() {
540 KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname);
541 }
542 #endif