1 /*
2 * Copyright (c) 1997, 2016, 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 #include "trace/tracing.hpp"
43
44 #define VM_OP_NAME_INITIALIZE(name) #name,
45
46 const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \
47 { VM_OPS_DO(VM_OP_NAME_INITIALIZE) };
48
49 void VM_Operation::set_calling_thread(Thread* thread, ThreadPriority priority) {
50 _calling_thread = thread;
51 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
52 _priority = priority;
53 }
54
55
56 void VM_Operation::evaluate() {
57 ResourceMark rm;
58 outputStream* debugstream;
59 bool enabled = log_is_enabled(Debug, vmoperation);
60 if (enabled) {
61 debugstream = Log(vmoperation)::debug_stream();
62 debugstream->print("begin ");
63 print_on_error(debugstream);
64 debugstream->cr();
65 }
66 doit();
67 if (enabled) {
68 debugstream->print("end ");
69 print_on_error(debugstream);
70 debugstream->cr();
71 }
72 }
73
74 const char* VM_Operation::mode_to_string(Mode mode) {
75 switch(mode) {
76 case _safepoint : return "safepoint";
77 case _no_safepoint : return "no safepoint";
78 case _concurrent : return "concurrent";
79 case _async_safepoint: return "async safepoint";
80 default : return "unknown";
81 }
82 }
83 // Called by fatal error handler.
84 void VM_Operation::print_on_error(outputStream* st) const {
85 st->print("VM_Operation (" PTR_FORMAT "): ", p2i(this));
86 st->print("%s", name());
87
88 const char* mode = mode_to_string(evaluation_mode());
89 st->print(", mode: %s", mode);
90
91 if (calling_thread()) {
92 st->print(", requested by thread " PTR_FORMAT, p2i(calling_thread()));
93 }
94 }
95
96 void VM_ThreadStop::doit() {
97 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
98 JavaThread* target = java_lang_Thread::thread(target_thread());
99 // Note that this now allows multiple ThreadDeath exceptions to be
100 // thrown at a thread.
101 if (target != NULL) {
102 // the thread has run and is not already in the process of exiting
103 target->send_thread_stop(throwable());
104 }
105 }
106
107 void VM_ClearICs::doit() {
108 if (_preserve_static_stubs) {
109 CodeCache::cleanup_inline_caches();
110 } else {
111 CodeCache::clear_inline_caches();
112 }
113 }
114
115 void VM_Deoptimize::doit() {
116 // We do not want any GCs to happen while we are in the middle of this VM operation
117 ResourceMark rm;
118 DeoptimizationMarker dm;
119
120 // Deoptimize all activations depending on marked nmethods
121 Deoptimization::deoptimize_dependents();
122
123 // Make the dependent methods not entrant
124 CodeCache::make_marked_nmethods_not_entrant();
125 }
126
127 void VM_MarkActiveNMethods::doit() {
128 NMethodSweeper::mark_active_nmethods();
129 }
130
131 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) {
132 _thread = thread;
133 _id = id;
134 _reason = reason;
135 }
136
137
138 void VM_DeoptimizeFrame::doit() {
139 assert(_reason > Deoptimization::Reason_none && _reason < Deoptimization::Reason_LIMIT, "invalid deopt reason");
140 Deoptimization::deoptimize_frame_internal(_thread, _id, (Deoptimization::DeoptReason)_reason);
141 }
142
143
144 #ifndef PRODUCT
145
146 void VM_DeoptimizeAll::doit() {
147 DeoptimizationMarker dm;
148 // deoptimize all java threads in the system
149 if (DeoptimizeALot) {
150 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
151 if (thread->has_last_Java_frame()) {
152 thread->deoptimize();
153 }
154 }
155 } else if (DeoptimizeRandom) {
156
157 // Deoptimize some selected threads and frames
158 int tnum = os::random() & 0x3;
159 int fnum = os::random() & 0x3;
160 int tcount = 0;
161 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
162 if (thread->has_last_Java_frame()) {
163 if (tcount++ == tnum) {
164 tcount = 0;
165 int fcount = 0;
166 // Deoptimize some selected frames.
167 // Biased llocking wants a updated register map
168 for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {
169 if (fst.current()->can_be_deoptimized()) {
170 if (fcount++ == fnum) {
171 fcount = 0;
172 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());
173 }
174 }
175 }
176 }
177 }
178 }
179 }
180 }
181
182
183 void VM_ZombieAll::doit() {
184 JavaThread *thread = (JavaThread *)calling_thread();
185 assert(thread->is_Java_thread(), "must be a Java thread");
186 thread->make_zombies();
187 }
188
189 #endif // !PRODUCT
190
191 void VM_UnlinkSymbols::doit() {
192 JavaThread *thread = (JavaThread *)calling_thread();
193 assert(thread->is_Java_thread(), "must be a Java thread");
194 SymbolTable::unlink();
195 }
196
197 void VM_Verify::doit() {
198 Universe::heap()->prepare_for_verify();
199 Universe::verify();
200 }
201
202 bool VM_PrintThreads::doit_prologue() {
203 // Make sure AbstractOwnableSynchronizer is loaded
204 JavaThread* jt = JavaThread::current();
205 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt);
206 if (jt->has_pending_exception()) {
207 return false;
208 }
209
210 // Get Heap_lock if concurrent locks will be dumped
211 if (_print_concurrent_locks) {
212 Heap_lock->lock();
213 }
214 return true;
215 }
216
217 void VM_PrintThreads::doit() {
218 Threads::print_on(_out, true, false, _print_concurrent_locks);
219 }
220
221 void VM_PrintThreads::doit_epilogue() {
222 if (_print_concurrent_locks) {
223 // Release Heap_lock
224 Heap_lock->unlock();
225 }
226 }
227
228 void VM_PrintJNI::doit() {
229 JNIHandles::print_on(_out);
230 }
231
232 VM_FindDeadlocks::~VM_FindDeadlocks() {
233 if (_deadlocks != NULL) {
234 DeadlockCycle* cycle = _deadlocks;
235 while (cycle != NULL) {
236 DeadlockCycle* d = cycle;
237 cycle = cycle->next();
238 delete d;
239 }
240 }
241 }
242
243 bool VM_FindDeadlocks::doit_prologue() {
244 if (_concurrent_locks) {
245 // Make sure AbstractOwnableSynchronizer is loaded
246 JavaThread* jt = JavaThread::current();
247 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt);
248 if (jt->has_pending_exception()) {
249 return false;
250 }
251 }
252
253 return true;
254 }
255
256 void VM_FindDeadlocks::doit() {
257 _deadlocks = ThreadService::find_deadlocks_at_safepoint(_concurrent_locks);
258 if (_out != NULL) {
259 int num_deadlocks = 0;
260 for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
261 num_deadlocks++;
262 cycle->print_on(_out);
263 }
264
265 if (num_deadlocks == 1) {
266 _out->print_cr("\nFound 1 deadlock.\n");
267 _out->flush();
268 } else if (num_deadlocks > 1) {
269 _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
270 _out->flush();
271 }
272 }
273 }
274
275 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
276 int max_depth,
277 bool with_locked_monitors,
278 bool with_locked_synchronizers) {
279 _result = result;
280 _num_threads = 0; // 0 indicates all threads
281 _threads = NULL;
282 _result = result;
283 _max_depth = max_depth;
284 _with_locked_monitors = with_locked_monitors;
285 _with_locked_synchronizers = with_locked_synchronizers;
286 }
287
288 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
289 GrowableArray<instanceHandle>* threads,
290 int num_threads,
291 int max_depth,
292 bool with_locked_monitors,
293 bool with_locked_synchronizers) {
294 _result = result;
295 _num_threads = num_threads;
296 _threads = threads;
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 bool VM_ThreadDump::doit_prologue() {
304 // Make sure AbstractOwnableSynchronizer is loaded
305 JavaThread* jt = JavaThread::current();
306 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt);
307 if (jt->has_pending_exception()) {
308 return false;
309 }
310
311 if (_with_locked_synchronizers) {
312 // Acquire Heap_lock to dump concurrent locks
313 Heap_lock->lock();
314 }
315
316 return true;
317 }
318
319 void VM_ThreadDump::doit_epilogue() {
320 if (_with_locked_synchronizers) {
321 // Release Heap_lock
322 Heap_lock->unlock();
323 }
324 }
325
326 void VM_ThreadDump::doit() {
327 ResourceMark rm;
328
329 ConcurrentLocksDump concurrent_locks(true);
330 if (_with_locked_synchronizers) {
331 concurrent_locks.dump_at_safepoint();
332 }
333
334 if (_num_threads == 0) {
335 // Snapshot all live threads
336 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
337 if (jt->is_exiting() ||
338 jt->is_hidden_from_external_view()) {
339 // skip terminating threads and hidden threads
340 continue;
341 }
342 ThreadConcurrentLocks* tcl = NULL;
343 if (_with_locked_synchronizers) {
344 tcl = concurrent_locks.thread_concurrent_locks(jt);
345 }
346 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
347 _result->add_thread_snapshot(ts);
348 }
349 } else {
350 // Snapshot threads in the given _threads array
351 // A dummy snapshot is created if a thread doesn't exist
352 for (int i = 0; i < _num_threads; i++) {
353 instanceHandle th = _threads->at(i);
354 if (th() == NULL) {
355 // skip if the thread doesn't exist
356 // Add a dummy snapshot
357 _result->add_thread_snapshot(new ThreadSnapshot());
358 continue;
359 }
360
361 // Dump thread stack only if the thread is alive and not exiting
362 // and not VM internal thread.
363 JavaThread* jt = java_lang_Thread::thread(th());
364 if (jt == NULL || /* thread not alive */
365 jt->is_exiting() ||
366 jt->is_hidden_from_external_view()) {
367 // add a NULL snapshot if skipped
368 _result->add_thread_snapshot(new ThreadSnapshot());
369 continue;
370 }
371 ThreadConcurrentLocks* tcl = NULL;
372 if (_with_locked_synchronizers) {
373 tcl = concurrent_locks.thread_concurrent_locks(jt);
374 }
375 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
376 _result->add_thread_snapshot(ts);
377 }
378 }
379 }
380
381 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
382 ThreadSnapshot* snapshot = new ThreadSnapshot(java_thread);
383 snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
384 snapshot->set_concurrent_locks(tcl);
385 return snapshot;
386 }
387
388 volatile bool VM_Exit::_vm_exited = false;
389 Thread * VM_Exit::_shutdown_thread = NULL;
390
391 int VM_Exit::set_vm_exited() {
392
393 Thread * thr_cur = Thread::current();
394
395 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
396
397 int num_active = 0;
398
399 _shutdown_thread = thr_cur;
400 _vm_exited = true; // global flag
401 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next())
402 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
403 ++num_active;
404 thr->set_terminated(JavaThread::_vm_exited); // per-thread flag
405 }
406
407 return num_active;
408 }
409
410 int VM_Exit::wait_for_threads_in_native_to_block() {
411 // VM exits at safepoint. This function must be called at the final safepoint
412 // to wait for threads in _thread_in_native state to be quiescent.
413 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
414
415 Thread * thr_cur = Thread::current();
416 Monitor timer(Mutex::leaf, "VM_Exit timer", true,
417 Monitor::_safepoint_check_never);
418
419 // Compiler threads need longer wait because they can access VM data directly
420 // while in native. If they are active and some structures being used are
421 // deleted by the shutdown sequence, they will crash. On the other hand, user
422 // threads must go through native=>Java/VM transitions first to access VM
423 // data, and they will be stopped during state transition. In theory, we
424 // don't have to wait for user threads to be quiescent, but it's always
425 // better to terminate VM when current thread is the only active thread, so
426 // wait for user threads too. Numbers are in 10 milliseconds.
427 int max_wait_user_thread = 30; // at least 300 milliseconds
428 int max_wait_compiler_thread = 1000; // at least 10 seconds
429
430 int max_wait = max_wait_compiler_thread;
431
432 int attempts = 0;
433 while (true) {
434 int num_active = 0;
435 int num_active_compiler_thread = 0;
436
437 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) {
438 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
439 num_active++;
440 if (thr->is_Compiler_thread()) {
441 num_active_compiler_thread++;
442 }
443 }
444 }
445
446 if (num_active == 0) {
447 return 0;
448 } else if (attempts > max_wait) {
449 return num_active;
450 } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
451 return num_active;
452 }
453
454 attempts++;
455
456 MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag);
457 timer.wait(Mutex::_no_safepoint_check_flag, 10);
458 }
459 }
460
461 void VM_Exit::doit() {
462 CompileBroker::set_should_block();
463
464 // Wait for a short period for threads in native to block. Any thread
465 // still executing native code after the wait will be stopped at
466 // native==>Java/VM barriers.
467 // Among 16276 JCK tests, 94% of them come here without any threads still
468 // running in native; the other 6% are quiescent within 250ms (Ultra 80).
469 wait_for_threads_in_native_to_block();
470
471 set_vm_exited();
472
473 // cleanup globals resources before exiting. exit_globals() currently
474 // cleans up outputStream resources and PerfMemory resources.
475 exit_globals();
476
477 // Check for exit hook
478 exit_hook_t exit_hook = Arguments::exit_hook();
479 if (exit_hook != NULL) {
480 // exit hook should exit.
481 exit_hook(_exit_code);
482 // ... but if it didn't, we must do it here
483 vm_direct_exit(_exit_code);
484 } else {
485 vm_direct_exit(_exit_code);
486 }
487 }
488
489
490 void VM_Exit::wait_if_vm_exited() {
491 if (_vm_exited &&
492 Thread::current_or_null() != _shutdown_thread) {
493 // _vm_exited is set at safepoint, and the Threads_lock is never released
494 // we will block here until the process dies
495 Threads_lock->lock_without_safepoint_check();
496 ShouldNotReachHere();
497 }
498 }
499
500 void VM_PrintCompileQueue::doit() {
501 CompileBroker::print_compile_queues(_out);
502 }
503
504 #if INCLUDE_SERVICES
505 void VM_PrintClassHierarchy::doit() {
506 KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname);
507 }
508 #endif