1 /* 2 * Copyright (c) 1997, 2013, 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 #include "trace/tracing.hpp" 41 42 #define VM_OP_NAME_INITIALIZE(name) #name, 43 44 const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \ 45 { VM_OPS_DO(VM_OP_NAME_INITIALIZE) }; 46 47 void VM_Operation::set_calling_thread(Thread* thread, ThreadPriority priority) { 48 _calling_thread = thread; 49 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 50 _priority = priority; 51 } 52 53 54 void VM_Operation::evaluate() { 55 ResourceMark rm; 56 if (TraceVMOperation) { 57 tty->print("["); 58 NOT_PRODUCT(print();) 59 } 60 doit(); 61 if (TraceVMOperation) { 62 tty->print_cr("]"); 63 } 64 } 65 66 const char* VM_Operation::mode_to_string(Mode mode) { 67 switch(mode) { 68 case _safepoint : return "safepoint"; 69 case _no_safepoint : return "no safepoint"; 70 case _concurrent : return "concurrent"; 71 case _async_safepoint: return "async safepoint"; 72 default : return "unknown"; 73 } 74 } 75 // Called by fatal error handler. 76 void VM_Operation::print_on_error(outputStream* st) const { 77 st->print("VM_Operation (" PTR_FORMAT "): ", this); 78 st->print("%s", name()); 79 80 const char* mode = mode_to_string(evaluation_mode()); 81 st->print(", mode: %s", mode); 82 83 if (calling_thread()) { 84 st->print(", requested by thread " PTR_FORMAT, calling_thread()); 85 } 86 } 87 88 void VM_ThreadStop::doit() { 89 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); 90 JavaThread* target = java_lang_Thread::thread(target_thread()); 91 // Note that this now allows multiple ThreadDeath exceptions to be 92 // thrown at a thread. 93 if (target != NULL) { 94 // the thread has run and is not already in the process of exiting 95 target->send_thread_stop(throwable()); 96 } 97 } 98 99 void VM_Deoptimize::doit() { 100 // We do not want any GCs to happen while we are in the middle of this VM operation 101 ResourceMark rm; 102 DeoptimizationMarker dm; 103 104 // Deoptimize all activations depending on marked nmethods 105 Deoptimization::deoptimize_dependents(); 106 107 // Make the dependent methods zombies 108 CodeCache::make_marked_nmethods_zombies(); 109 } 110 111 112 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id) { 113 _thread = thread; 114 _id = id; 115 } 116 117 118 void VM_DeoptimizeFrame::doit() { 119 Deoptimization::deoptimize_frame_internal(_thread, _id); 120 } 121 122 123 #ifndef PRODUCT 124 125 void VM_DeoptimizeAll::doit() { 126 DeoptimizationMarker dm; 127 // deoptimize all java threads in the system 128 if (DeoptimizeALot) { 129 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 130 if (thread->has_last_Java_frame()) { 131 thread->deoptimize(); 132 } 133 } 134 } else if (DeoptimizeRandom) { 135 136 // Deoptimize some selected threads and frames 137 int tnum = os::random() & 0x3; 138 int fnum = os::random() & 0x3; 139 int tcount = 0; 140 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 141 if (thread->has_last_Java_frame()) { 142 if (tcount++ == tnum) { 143 tcount = 0; 144 int fcount = 0; 145 // Deoptimize some selected frames. 146 // Biased llocking wants a updated register map 147 for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) { 148 if (fst.current()->can_be_deoptimized()) { 149 if (fcount++ == fnum) { 150 fcount = 0; 151 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map()); 152 } 153 } 154 } 155 } 156 } 157 } 158 } 159 } 160 161 162 void VM_ZombieAll::doit() { 163 JavaThread *thread = (JavaThread *)calling_thread(); 164 assert(thread->is_Java_thread(), "must be a Java thread"); 165 thread->make_zombies(); 166 } 167 168 #endif // !PRODUCT 169 170 void VM_UnlinkSymbols::doit() { 171 JavaThread *thread = (JavaThread *)calling_thread(); 172 assert(thread->is_Java_thread(), "must be a Java thread"); 173 SymbolTable::unlink(); 174 } 175 176 void VM_Verify::doit() { 177 Universe::heap()->prepare_for_verify(); 178 Universe::verify(_silent); 179 } 180 181 bool VM_PrintThreads::doit_prologue() { 182 assert(Thread::current()->is_Java_thread(), "just checking"); 183 184 // Make sure AbstractOwnableSynchronizer is loaded 185 if (JDK_Version::is_gte_jdk16x_version()) { 186 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current()); 187 } 188 189 // Get Heap_lock if concurrent locks will be dumped 190 if (_print_concurrent_locks) { 191 Heap_lock->lock(); 192 } 193 return true; 194 } 195 196 void VM_PrintThreads::doit() { 197 Threads::print_on(_out, true, false, _print_concurrent_locks); 198 } 199 200 void VM_PrintThreads::doit_epilogue() { 201 if (_print_concurrent_locks) { 202 // Release Heap_lock 203 Heap_lock->unlock(); 204 } 205 } 206 207 void VM_PrintJNI::doit() { 208 JNIHandles::print_on(_out); 209 } 210 211 VM_FindDeadlocks::~VM_FindDeadlocks() { 212 if (_deadlocks != NULL) { 213 DeadlockCycle* cycle = _deadlocks; 214 while (cycle != NULL) { 215 DeadlockCycle* d = cycle; 216 cycle = cycle->next(); 217 delete d; 218 } 219 } 220 } 221 222 bool VM_FindDeadlocks::doit_prologue() { 223 assert(Thread::current()->is_Java_thread(), "just checking"); 224 225 // Load AbstractOwnableSynchronizer class 226 if (_concurrent_locks && JDK_Version::is_gte_jdk16x_version()) { 227 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current()); 228 } 229 230 return true; 231 } 232 233 void VM_FindDeadlocks::doit() { 234 _deadlocks = ThreadService::find_deadlocks_at_safepoint(_concurrent_locks); 235 if (_out != NULL) { 236 int num_deadlocks = 0; 237 for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) { 238 num_deadlocks++; 239 cycle->print_on(_out); 240 } 241 242 if (num_deadlocks == 1) { 243 _out->print_cr("\nFound 1 deadlock.\n"); 244 _out->flush(); 245 } else if (num_deadlocks > 1) { 246 _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks); 247 _out->flush(); 248 } 249 } 250 } 251 252 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result, 253 int max_depth, 254 bool with_locked_monitors, 255 bool with_locked_synchronizers) { 256 _result = result; 257 _num_threads = 0; // 0 indicates all threads 258 _threads = NULL; 259 _result = result; 260 _max_depth = max_depth; 261 _with_locked_monitors = with_locked_monitors; 262 _with_locked_synchronizers = with_locked_synchronizers; 263 } 264 265 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result, 266 GrowableArray<instanceHandle>* threads, 267 int num_threads, 268 int max_depth, 269 bool with_locked_monitors, 270 bool with_locked_synchronizers) { 271 _result = result; 272 _num_threads = num_threads; 273 _threads = threads; 274 _result = result; 275 _max_depth = max_depth; 276 _with_locked_monitors = with_locked_monitors; 277 _with_locked_synchronizers = with_locked_synchronizers; 278 } 279 280 bool VM_ThreadDump::doit_prologue() { 281 assert(Thread::current()->is_Java_thread(), "just checking"); 282 283 // Load AbstractOwnableSynchronizer class before taking thread snapshots 284 if (JDK_Version::is_gte_jdk16x_version()) { 285 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current()); 286 } 287 288 if (_with_locked_synchronizers) { 289 // Acquire Heap_lock to dump concurrent locks 290 Heap_lock->lock(); 291 } 292 293 return true; 294 } 295 296 void VM_ThreadDump::doit_epilogue() { 297 if (_with_locked_synchronizers) { 298 // Release Heap_lock 299 Heap_lock->unlock(); 300 } 301 } 302 303 void VM_ThreadDump::doit() { 304 ResourceMark rm; 305 306 ConcurrentLocksDump concurrent_locks(true); 307 if (_with_locked_synchronizers) { 308 concurrent_locks.dump_at_safepoint(); 309 } 310 311 if (_num_threads == 0) { 312 // Snapshot all live threads 313 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) { 314 if (jt->is_exiting() || 315 jt->is_hidden_from_external_view()) { 316 // skip terminating threads and hidden threads 317 continue; 318 } 319 ThreadConcurrentLocks* tcl = NULL; 320 if (_with_locked_synchronizers) { 321 tcl = concurrent_locks.thread_concurrent_locks(jt); 322 } 323 ThreadSnapshot* ts = snapshot_thread(jt, tcl); 324 _result->add_thread_snapshot(ts); 325 } 326 } else { 327 // Snapshot threads in the given _threads array 328 // A dummy snapshot is created if a thread doesn't exist 329 for (int i = 0; i < _num_threads; i++) { 330 instanceHandle th = _threads->at(i); 331 if (th() == NULL) { 332 // skip if the thread doesn't exist 333 // Add a dummy snapshot 334 _result->add_thread_snapshot(new ThreadSnapshot()); 335 continue; 336 } 337 338 // Dump thread stack only if the thread is alive and not exiting 339 // and not VM internal thread. 340 JavaThread* jt = java_lang_Thread::thread(th()); 341 if (jt == NULL || /* thread not alive */ 342 jt->is_exiting() || 343 jt->is_hidden_from_external_view()) { 344 // add a NULL snapshot if skipped 345 _result->add_thread_snapshot(new ThreadSnapshot()); 346 continue; 347 } 348 ThreadConcurrentLocks* tcl = NULL; 349 if (_with_locked_synchronizers) { 350 tcl = concurrent_locks.thread_concurrent_locks(jt); 351 } 352 ThreadSnapshot* ts = snapshot_thread(jt, tcl); 353 _result->add_thread_snapshot(ts); 354 } 355 } 356 } 357 358 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) { 359 ThreadSnapshot* snapshot = new ThreadSnapshot(java_thread); 360 snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors); 361 snapshot->set_concurrent_locks(tcl); 362 return snapshot; 363 } 364 365 volatile bool VM_Exit::_vm_exited = false; 366 Thread * VM_Exit::_shutdown_thread = NULL; 367 368 int VM_Exit::set_vm_exited() { 369 Thread * thr_cur = ThreadLocalStorage::get_thread_slow(); 370 371 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already"); 372 373 int num_active = 0; 374 375 _shutdown_thread = thr_cur; 376 _vm_exited = true; // global flag 377 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) 378 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) { 379 ++num_active; 380 thr->set_terminated(JavaThread::_vm_exited); // per-thread flag 381 } 382 383 return num_active; 384 } 385 386 int VM_Exit::wait_for_threads_in_native_to_block() { 387 // VM exits at safepoint. This function must be called at the final safepoint 388 // to wait for threads in _thread_in_native state to be quiescent. 389 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already"); 390 391 Thread * thr_cur = ThreadLocalStorage::get_thread_slow(); 392 Monitor timer(Mutex::leaf, "VM_Exit timer", true); 393 394 // Compiler threads need longer wait because they can access VM data directly 395 // while in native. If they are active and some structures being used are 396 // deleted by the shutdown sequence, they will crash. On the other hand, user 397 // threads must go through native=>Java/VM transitions first to access VM 398 // data, and they will be stopped during state transition. In theory, we 399 // don't have to wait for user threads to be quiescent, but it's always 400 // better to terminate VM when current thread is the only active thread, so 401 // wait for user threads too. Numbers are in 10 milliseconds. 402 int max_wait_user_thread = 30; // at least 300 milliseconds 403 int max_wait_compiler_thread = 1000; // at least 10 seconds 404 405 int max_wait = max_wait_compiler_thread; 406 407 int attempts = 0; 408 while (true) { 409 int num_active = 0; 410 int num_active_compiler_thread = 0; 411 412 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) { 413 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) { 414 num_active++; 415 if (thr->is_Compiler_thread()) { 416 num_active_compiler_thread++; 417 } 418 } 419 } 420 421 if (num_active == 0) { 422 return 0; 423 } else if (attempts > max_wait) { 424 return num_active; 425 } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) { 426 return num_active; 427 } 428 429 attempts++; 430 431 MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag); 432 timer.wait(Mutex::_no_safepoint_check_flag, 10); 433 } 434 } 435 436 void VM_Exit::doit() { 437 CompileBroker::set_should_block(); 438 439 // Wait for a short period for threads in native to block. Any thread 440 // still executing native code after the wait will be stopped at 441 // native==>Java/VM barriers. 442 // Among 16276 JCK tests, 94% of them come here without any threads still 443 // running in native; the other 6% are quiescent within 250ms (Ultra 80). 444 wait_for_threads_in_native_to_block(); 445 446 set_vm_exited(); 447 448 // cleanup globals resources before exiting. exit_globals() currently 449 // cleans up outputStream resources and PerfMemory resources. 450 exit_globals(); 451 452 // Check for exit hook 453 exit_hook_t exit_hook = Arguments::exit_hook(); 454 if (exit_hook != NULL) { 455 // exit hook should exit. 456 exit_hook(_exit_code); 457 // ... but if it didn't, we must do it here 458 vm_direct_exit(_exit_code); 459 } else { 460 vm_direct_exit(_exit_code); 461 } 462 } 463 464 465 void VM_Exit::wait_if_vm_exited() { 466 if (_vm_exited && 467 ThreadLocalStorage::get_thread_slow() != _shutdown_thread) { 468 // _vm_exited is set at safepoint, and the Threads_lock is never released 469 // we will block here until the process dies 470 Threads_lock->lock_without_safepoint_check(); 471 ShouldNotReachHere(); 472 } 473 }