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