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 "compiler/compileBroker.hpp"
29 #include "compiler/compilerOracle.hpp"
30 #include "gc_implementation/shared/isGCActiveMark.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "oops/symbol.hpp"
33 #include "runtime/arguments.hpp"
34 #include "runtime/deoptimization.hpp"
35 #include "runtime/interfaceSupport.hpp"
36 #include "runtime/sweeper.hpp"
37 #include "runtime/thread.inline.hpp"
38 #include "runtime/vm_operations.hpp"
39 #include "services/threadService.hpp"
40
41 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
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 if (TraceVMOperation) {
58 tty->print("[");
59 NOT_PRODUCT(print();)
60 }
61 doit();
62 if (TraceVMOperation) {
63 tty->print_cr("]");
64 }
65 }
66
67 const char* VM_Operation::mode_to_string(Mode mode) {
68 switch(mode) {
69 case _safepoint : return "safepoint";
70 case _no_safepoint : return "no safepoint";
71 case _concurrent : return "concurrent";
72 case _async_safepoint: return "async safepoint";
73 default : return "unknown";
74 }
75 }
76 // Called by fatal error handler.
77 void VM_Operation::print_on_error(outputStream* st) const {
78 st->print("VM_Operation (" PTR_FORMAT "): ", this);
79 st->print("%s", name());
80
81 const char* mode = mode_to_string(evaluation_mode());
82 st->print(", mode: %s", mode);
83
84 if (calling_thread()) {
85 st->print(", requested by thread " PTR_FORMAT, calling_thread());
86 }
87 }
88
89 void VM_ThreadStop::doit() {
90 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
91 JavaThread* target = java_lang_Thread::thread(target_thread());
92 // Note that this now allows multiple ThreadDeath exceptions to be
93 // thrown at a thread.
94 if (target != NULL) {
95 // the thread has run and is not already in the process of exiting
96 target->send_thread_stop(throwable());
97 }
98 }
99
100 void VM_Deoptimize::doit() {
101 // We do not want any GCs to happen while we are in the middle of this VM operation
102 ResourceMark rm;
103 DeoptimizationMarker dm;
104
105 // Deoptimize all activations depending on marked nmethods
106 Deoptimization::deoptimize_dependents();
107
108 // Make the dependent methods not entrant
109 CodeCache::make_marked_nmethods_not_entrant();
110 }
111
112
113 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id) {
114 _thread = thread;
115 _id = id;
116 }
117
118
119 void VM_DeoptimizeFrame::doit() {
120 Deoptimization::deoptimize_frame_internal(_thread, _id);
121 }
122
123
124 #ifndef PRODUCT
125
126 void VM_DeoptimizeAll::doit() {
127 DeoptimizationMarker dm;
128 // deoptimize all java threads in the system
129 if (DeoptimizeALot) {
130 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
131 if (thread->has_last_Java_frame()) {
132 thread->deoptimize();
133 }
134 }
135 } else if (DeoptimizeRandom) {
136
137 // Deoptimize some selected threads and frames
138 int tnum = os::random() & 0x3;
139 int fnum = os::random() & 0x3;
140 int tcount = 0;
141 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
142 if (thread->has_last_Java_frame()) {
143 if (tcount++ == tnum) {
144 tcount = 0;
145 int fcount = 0;
146 // Deoptimize some selected frames.
147 // Biased llocking wants a updated register map
148 for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {
149 if (fst.current()->can_be_deoptimized()) {
150 if (fcount++ == fnum) {
151 fcount = 0;
152 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());
153 }
154 }
155 }
156 }
157 }
158 }
159 }
160 }
161
162
163 void VM_ZombieAll::doit() {
164 JavaThread *thread = (JavaThread *)calling_thread();
165 assert(thread->is_Java_thread(), "must be a Java thread");
166 thread->make_zombies();
167 }
168
169 #endif // !PRODUCT
170
171 void VM_UnlinkSymbols::doit() {
172 JavaThread *thread = (JavaThread *)calling_thread();
173 assert(thread->is_Java_thread(), "must be a Java thread");
174 SymbolTable::unlink();
175 }
176
177 void VM_Verify::doit() {
178 Universe::heap()->prepare_for_verify();
179 Universe::verify(_silent);
180 }
181
182 bool VM_PrintThreads::doit_prologue() {
183 assert(Thread::current()->is_Java_thread(), "just checking");
184
185 // Make sure AbstractOwnableSynchronizer is loaded
186 if (JDK_Version::is_gte_jdk16x_version()) {
187 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
188 }
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 && JDK_Version::is_gte_jdk16x_version()) {
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 if (JDK_Version::is_gte_jdk16x_version()) {
286 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
287 }
288
289 if (_with_locked_synchronizers) {
290 // Acquire Heap_lock to dump concurrent locks
291 Heap_lock->lock();
292 }
293
294 return true;
295 }
296
297 void VM_ThreadDump::doit_epilogue() {
298 if (_with_locked_synchronizers) {
299 // Release Heap_lock
300 Heap_lock->unlock();
301 }
302 }
303
304 void VM_ThreadDump::doit() {
305 ResourceMark rm;
306
307 ConcurrentLocksDump concurrent_locks(true);
308 if (_with_locked_synchronizers) {
309 concurrent_locks.dump_at_safepoint();
310 }
311
312 if (_num_threads == 0) {
313 // Snapshot all live threads
314 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
315 if (jt->is_exiting() ||
316 jt->is_hidden_from_external_view()) {
317 // skip terminating threads and hidden threads
318 continue;
319 }
320 ThreadConcurrentLocks* tcl = NULL;
321 if (_with_locked_synchronizers) {
322 tcl = concurrent_locks.thread_concurrent_locks(jt);
323 }
324 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
325 _result->add_thread_snapshot(ts);
326 }
327 } else {
328 // Snapshot threads in the given _threads array
329 // A dummy snapshot is created if a thread doesn't exist
330 for (int i = 0; i < _num_threads; i++) {
331 instanceHandle th = _threads->at(i);
332 if (th() == NULL) {
333 // skip if the thread doesn't exist
334 // Add a dummy snapshot
335 _result->add_thread_snapshot(new ThreadSnapshot());
336 continue;
337 }
338
339 // Dump thread stack only if the thread is alive and not exiting
340 // and not VM internal thread.
341 JavaThread* jt = java_lang_Thread::thread(th());
342 if (jt == NULL || /* thread not alive */
343 jt->is_exiting() ||
344 jt->is_hidden_from_external_view()) {
345 // add a NULL snapshot if skipped
346 _result->add_thread_snapshot(new ThreadSnapshot());
347 continue;
348 }
349 ThreadConcurrentLocks* tcl = NULL;
350 if (_with_locked_synchronizers) {
351 tcl = concurrent_locks.thread_concurrent_locks(jt);
352 }
353 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
354 _result->add_thread_snapshot(ts);
355 }
356 }
357 }
358
359 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
360 ThreadSnapshot* snapshot = new ThreadSnapshot(java_thread);
361 snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
362 snapshot->set_concurrent_locks(tcl);
363 return snapshot;
364 }
365
366 volatile bool VM_Exit::_vm_exited = false;
367 Thread * VM_Exit::_shutdown_thread = NULL;
368
369 int VM_Exit::set_vm_exited() {
370 Thread * thr_cur = ThreadLocalStorage::get_thread_slow();
371
372 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
373
374 int num_active = 0;
375
376 _shutdown_thread = thr_cur;
377 _vm_exited = true; // global flag
378 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next())
379 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
380 ++num_active;
381 thr->set_terminated(JavaThread::_vm_exited); // per-thread flag
382 }
383
384 return num_active;
385 }
386
387 int VM_Exit::wait_for_threads_in_native_to_block() {
388 // VM exits at safepoint. This function must be called at the final safepoint
389 // to wait for threads in _thread_in_native state to be quiescent.
390 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
391
392 Thread * thr_cur = ThreadLocalStorage::get_thread_slow();
393 Monitor timer(Mutex::leaf, "VM_Exit timer", true);
394
395 // Compiler threads need longer wait because they can access VM data directly
396 // while in native. If they are active and some structures being used are
397 // deleted by the shutdown sequence, they will crash. On the other hand, user
398 // threads must go through native=>Java/VM transitions first to access VM
399 // data, and they will be stopped during state transition. In theory, we
400 // don't have to wait for user threads to be quiescent, but it's always
401 // better to terminate VM when current thread is the only active thread, so
402 // wait for user threads too. Numbers are in 10 milliseconds.
403 int max_wait_user_thread = 30; // at least 300 milliseconds
404 int max_wait_compiler_thread = 1000; // at least 10 seconds
405
406 int max_wait = max_wait_compiler_thread;
407
408 int attempts = 0;
409 while (true) {
410 int num_active = 0;
411 int num_active_compiler_thread = 0;
412
413 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) {
414 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
415 num_active++;
416 if (thr->is_Compiler_thread()) {
417 num_active_compiler_thread++;
418 }
419 }
420 }
421
422 if (num_active == 0) {
423 return 0;
424 } else if (attempts > max_wait) {
425 return num_active;
426 } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
427 return num_active;
428 }
429
430 attempts++;
431
432 MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag);
433 timer.wait(Mutex::_no_safepoint_check_flag, 10);
434 }
435 }
436
437 void VM_Exit::doit() {
438 CompileBroker::set_should_block();
439
440 // Wait for a short period for threads in native to block. Any thread
441 // still executing native code after the wait will be stopped at
442 // native==>Java/VM barriers.
443 // Among 16276 JCK tests, 94% of them come here without any threads still
444 // running in native; the other 6% are quiescent within 250ms (Ultra 80).
445 wait_for_threads_in_native_to_block();
446
447 set_vm_exited();
448
449 // cleanup globals resources before exiting. exit_globals() currently
450 // cleans up outputStream resources and PerfMemory resources.
451 exit_globals();
452
453 // Check for exit hook
454 exit_hook_t exit_hook = Arguments::exit_hook();
455 if (exit_hook != NULL) {
456 // exit hook should exit.
457 exit_hook(_exit_code);
458 // ... but if it didn't, we must do it here
459 vm_direct_exit(_exit_code);
460 } else {
461 vm_direct_exit(_exit_code);
462 }
463 }
464
465
466 void VM_Exit::wait_if_vm_exited() {
467 if (_vm_exited &&
468 ThreadLocalStorage::get_thread_slow() != _shutdown_thread) {
469 // _vm_exited is set at safepoint, and the Threads_lock is never released
470 // we will block here until the process dies
471 Threads_lock->lock_without_safepoint_check();
472 ShouldNotReachHere();
473 }
474 }