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