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