1 /*
2 * Copyright (c) 1997, 2014, 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 "compiler/compilerOracle.hpp"
31 #include "gc_implementation/shared/isGCActiveMark.hpp"
32 #include "memory/resourceArea.hpp"
33 #include "oops/symbol.hpp"
34 #include "runtime/arguments.hpp"
35 #include "runtime/deoptimization.hpp"
36 #include "runtime/interfaceSupport.hpp"
37 #include "runtime/sweeper.hpp"
38 #include "runtime/thread.inline.hpp"
39 #include "runtime/vm_operations.hpp"
40 #include "services/threadService.hpp"
41 #include "trace/tracing.hpp"
42
43 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
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 if (TraceVMOperation) {
60 tty->print("[");
61 NOT_PRODUCT(print();)
62 }
63 doit();
64 if (TraceVMOperation) {
65 tty->print_cr("]");
66 }
67 }
68
69 const char* VM_Operation::mode_to_string(Mode mode) {
70 switch(mode) {
71 case _safepoint : return "safepoint";
72 case _no_safepoint : return "no safepoint";
73 case _concurrent : return "concurrent";
74 case _async_safepoint: return "async safepoint";
75 default : return "unknown";
76 }
77 }
78 // Called by fatal error handler.
79 void VM_Operation::print_on_error(outputStream* st) const {
80 st->print("VM_Operation (" PTR_FORMAT "): ", this);
81 st->print("%s", name());
82
83 const char* mode = mode_to_string(evaluation_mode());
84 st->print(", mode: %s", mode);
85
86 if (calling_thread()) {
87 st->print(", requested by thread " PTR_FORMAT, calling_thread());
88 }
89 }
90
91 void VM_ThreadStop::doit() {
92 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
93 JavaThread* target = java_lang_Thread::thread(target_thread());
94 // Note that this now allows multiple ThreadDeath exceptions to be
95 // thrown at a thread.
96 if (target != NULL) {
97 // the thread has run and is not already in the process of exiting
98 target->send_thread_stop(throwable());
99 }
100 }
101
102 void VM_Deoptimize::doit() {
103 // We do not want any GCs to happen while we are in the middle of this VM operation
104 ResourceMark rm;
105 DeoptimizationMarker dm;
106
107 // Deoptimize all activations depending on marked nmethods
108 Deoptimization::deoptimize_dependents();
109
110 // Make the dependent methods zombies
111 CodeCache::make_marked_nmethods_zombies();
112 }
113
114
115 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id) {
116 _thread = thread;
117 _id = id;
118 }
119
120
121 void VM_DeoptimizeFrame::doit() {
122 Deoptimization::deoptimize_frame_internal(_thread, _id);
123 }
124
125
126 #ifndef PRODUCT
127
128 void VM_DeoptimizeAll::doit() {
129 DeoptimizationMarker dm;
130 // deoptimize all java threads in the system
131 if (DeoptimizeALot) {
132 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
133 if (thread->has_last_Java_frame()) {
134 thread->deoptimize();
135 }
136 }
137 } else if (DeoptimizeRandom) {
138
139 // Deoptimize some selected threads and frames
140 int tnum = os::random() & 0x3;
141 int fnum = os::random() & 0x3;
142 int tcount = 0;
143 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
144 if (thread->has_last_Java_frame()) {
145 if (tcount++ == tnum) {
146 tcount = 0;
147 int fcount = 0;
148 // Deoptimize some selected frames.
149 // Biased llocking wants a updated register map
150 for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {
151 if (fst.current()->can_be_deoptimized()) {
152 if (fcount++ == fnum) {
153 fcount = 0;
154 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());
155 }
156 }
157 }
158 }
159 }
160 }
161 }
162 }
163
164
165 void VM_ZombieAll::doit() {
166 JavaThread *thread = (JavaThread *)calling_thread();
167 assert(thread->is_Java_thread(), "must be a Java thread");
168 thread->make_zombies();
169 }
170
171 #endif // !PRODUCT
172
173 void VM_UnlinkSymbols::doit() {
174 JavaThread *thread = (JavaThread *)calling_thread();
175 assert(thread->is_Java_thread(), "must be a Java thread");
176 SymbolTable::unlink();
177 }
178
179 void VM_Verify::doit() {
180 Universe::heap()->prepare_for_verify();
181 Universe::verify(_silent);
182 }
183
184 bool VM_PrintThreads::doit_prologue() {
185 assert(Thread::current()->is_Java_thread(), "just checking");
186
187 // Make sure AbstractOwnableSynchronizer is loaded
188 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
189
190 // Get Heap_lock if concurrent locks will be dumped
191 if (_print_concurrent_locks) {
192 Heap_lock->lock();
193 }
194 return true;
195 }
196
197 void VM_PrintThreads::doit() {
198 Threads::print_on(_out, true, false, _print_concurrent_locks);
199 }
200
201 void VM_PrintThreads::doit_epilogue() {
202 if (_print_concurrent_locks) {
203 // Release Heap_lock
204 Heap_lock->unlock();
205 }
206 }
207
208 void VM_PrintJNI::doit() {
209 JNIHandles::print_on(_out);
210 }
211
212 VM_FindDeadlocks::~VM_FindDeadlocks() {
213 if (_deadlocks != NULL) {
214 DeadlockCycle* cycle = _deadlocks;
215 while (cycle != NULL) {
216 DeadlockCycle* d = cycle;
217 cycle = cycle->next();
218 delete d;
219 }
220 }
221 }
222
223 bool VM_FindDeadlocks::doit_prologue() {
224 assert(Thread::current()->is_Java_thread(), "just checking");
225
226 // Load AbstractOwnableSynchronizer class
227 if (_concurrent_locks) {
228 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
229 }
230
231 return true;
232 }
233
234 void VM_FindDeadlocks::doit() {
235 _deadlocks = ThreadService::find_deadlocks_at_safepoint(_concurrent_locks);
236 if (_out != NULL) {
237 int num_deadlocks = 0;
238 for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
239 num_deadlocks++;
240 cycle->print_on(_out);
241 }
242
243 if (num_deadlocks == 1) {
244 _out->print_cr("\nFound 1 deadlock.\n");
245 _out->flush();
246 } else if (num_deadlocks > 1) {
247 _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
248 _out->flush();
249 }
250 }
251 }
252
253 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
254 int max_depth,
255 bool with_locked_monitors,
256 bool with_locked_synchronizers) {
257 _result = result;
258 _num_threads = 0; // 0 indicates all threads
259 _threads = NULL;
260 _result = result;
261 _max_depth = max_depth;
262 _with_locked_monitors = with_locked_monitors;
263 _with_locked_synchronizers = with_locked_synchronizers;
264 }
265
266 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
267 GrowableArray<instanceHandle>* threads,
268 int num_threads,
269 int max_depth,
270 bool with_locked_monitors,
271 bool with_locked_synchronizers) {
272 _result = result;
273 _num_threads = num_threads;
274 _threads = threads;
275 _result = result;
276 _max_depth = max_depth;
277 _with_locked_monitors = with_locked_monitors;
278 _with_locked_synchronizers = with_locked_synchronizers;
279 }
280
281 bool VM_ThreadDump::doit_prologue() {
282 assert(Thread::current()->is_Java_thread(), "just checking");
283
284 // Load AbstractOwnableSynchronizer class before taking thread snapshots
285 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
286
287 if (_with_locked_synchronizers) {
288 // Acquire Heap_lock to dump concurrent locks
289 Heap_lock->lock();
290 }
291
292 return true;
293 }
294
295 void VM_ThreadDump::doit_epilogue() {
296 if (_with_locked_synchronizers) {
297 // Release Heap_lock
298 Heap_lock->unlock();
299 }
300 }
301
302 void VM_ThreadDump::doit() {
303 ResourceMark rm;
304
305 ConcurrentLocksDump concurrent_locks(true);
306 if (_with_locked_synchronizers) {
307 concurrent_locks.dump_at_safepoint();
308 }
309
310 if (_num_threads == 0) {
311 // Snapshot all live threads
312 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
313 if (jt->is_exiting() ||
314 jt->is_hidden_from_external_view()) {
315 // skip terminating threads and hidden threads
316 continue;
317 }
318 ThreadConcurrentLocks* tcl = NULL;
319 if (_with_locked_synchronizers) {
320 tcl = concurrent_locks.thread_concurrent_locks(jt);
321 }
322 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
323 _result->add_thread_snapshot(ts);
324 }
325 } else {
326 // Snapshot threads in the given _threads array
327 // A dummy snapshot is created if a thread doesn't exist
328 for (int i = 0; i < _num_threads; i++) {
329 instanceHandle th = _threads->at(i);
330 if (th() == NULL) {
331 // skip if the thread doesn't exist
332 // Add a dummy snapshot
333 _result->add_thread_snapshot(new ThreadSnapshot());
334 continue;
335 }
336
337 // Dump thread stack only if the thread is alive and not exiting
338 // and not VM internal thread.
339 JavaThread* jt = java_lang_Thread::thread(th());
340 if (jt == NULL || /* thread not alive */
341 jt->is_exiting() ||
342 jt->is_hidden_from_external_view()) {
343 // add a NULL snapshot if skipped
344 _result->add_thread_snapshot(new ThreadSnapshot());
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 }
355 }
356
357 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
358 ThreadSnapshot* snapshot = new ThreadSnapshot(java_thread);
359 snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
360 snapshot->set_concurrent_locks(tcl);
361 return snapshot;
362 }
363
364 volatile bool VM_Exit::_vm_exited = false;
365 Thread * VM_Exit::_shutdown_thread = NULL;
366
367 int VM_Exit::set_vm_exited() {
368 Thread * thr_cur = ThreadLocalStorage::get_thread_slow();
369
370 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
371
372 int num_active = 0;
373
374 _shutdown_thread = thr_cur;
375 _vm_exited = true; // global flag
376 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next())
377 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
378 ++num_active;
379 thr->set_terminated(JavaThread::_vm_exited); // per-thread flag
380 }
381
382 return num_active;
383 }
384
385 int VM_Exit::wait_for_threads_in_native_to_block() {
386 // VM exits at safepoint. This function must be called at the final safepoint
387 // to wait for threads in _thread_in_native state to be quiescent.
388 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
389
390 Thread * thr_cur = ThreadLocalStorage::get_thread_slow();
391 Monitor timer(Mutex::leaf, "VM_Exit timer", true);
392
393 // Compiler threads need longer wait because they can access VM data directly
394 // while in native. If they are active and some structures being used are
395 // deleted by the shutdown sequence, they will crash. On the other hand, user
396 // threads must go through native=>Java/VM transitions first to access VM
397 // data, and they will be stopped during state transition. In theory, we
398 // don't have to wait for user threads to be quiescent, but it's always
399 // better to terminate VM when current thread is the only active thread, so
400 // wait for user threads too. Numbers are in 10 milliseconds.
401 int max_wait_user_thread = 30; // at least 300 milliseconds
402 int max_wait_compiler_thread = 1000; // at least 10 seconds
403
404 int max_wait = max_wait_compiler_thread;
405
406 int attempts = 0;
407 while (true) {
408 int num_active = 0;
409 int num_active_compiler_thread = 0;
410
411 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) {
412 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
413 num_active++;
414 if (thr->is_Compiler_thread()) {
415 num_active_compiler_thread++;
416 }
417 }
418 }
419
420 if (num_active == 0) {
421 return 0;
422 } else if (attempts > max_wait) {
423 return num_active;
424 } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
425 return num_active;
426 }
427
428 attempts++;
429
430 MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag);
431 timer.wait(Mutex::_no_safepoint_check_flag, 10);
432 }
433 }
434
435 void VM_Exit::doit() {
436 CompileBroker::set_should_block();
437
438 // Wait for a short period for threads in native to block. Any thread
439 // still executing native code after the wait will be stopped at
440 // native==>Java/VM barriers.
441 // Among 16276 JCK tests, 94% of them come here without any threads still
442 // running in native; the other 6% are quiescent within 250ms (Ultra 80).
443 wait_for_threads_in_native_to_block();
444
445 set_vm_exited();
446
447 // cleanup globals resources before exiting. exit_globals() currently
448 // cleans up outputStream resources and PerfMemory resources.
449 exit_globals();
450
451 // Check for exit hook
452 exit_hook_t exit_hook = Arguments::exit_hook();
453 if (exit_hook != NULL) {
454 // exit hook should exit.
455 exit_hook(_exit_code);
456 // ... but if it didn't, we must do it here
457 vm_direct_exit(_exit_code);
458 } else {
459 vm_direct_exit(_exit_code);
460 }
461 }
462
463
464 void VM_Exit::wait_if_vm_exited() {
465 if (_vm_exited &&
466 ThreadLocalStorage::get_thread_slow() != _shutdown_thread) {
467 // _vm_exited is set at safepoint, and the Threads_lock is never released
468 // we will block here until the process dies
469 Threads_lock->lock_without_safepoint_check();
470 ShouldNotReachHere();
471 }
472 }