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 "logging/logStream.hpp" 33 #include "memory/heapInspection.hpp" 34 #include "memory/resourceArea.hpp" 35 #include "oops/symbol.hpp" 36 #include "runtime/arguments.hpp" 37 #include "runtime/deoptimization.hpp" 38 #include "runtime/interfaceSupport.hpp" 39 #include "runtime/sweeper.hpp" 40 #include "runtime/thread.inline.hpp" 41 #include "runtime/vm_operations.hpp" 42 #include "services/threadService.hpp" 43 #include "trace/tracing.hpp" 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 LogTarget(Debug, vmoperation) lt; 60 if (lt.is_enabled()) { 61 LogStream ls(lt); 62 ls.print("begin "); 63 print_on_error(&ls); 64 ls.cr(); 65 } 66 doit(); 67 if (lt.is_enabled()) { 68 LogStream ls(lt); 69 ls.print("end "); 70 print_on_error(&ls); 71 ls.cr(); 72 } 73 } 74 75 const char* VM_Operation::mode_to_string(Mode mode) { 76 switch(mode) { 77 case _safepoint : return "safepoint"; 78 case _no_safepoint : return "no safepoint"; 79 case _concurrent : return "concurrent"; 80 case _async_safepoint: return "async safepoint"; 81 default : return "unknown"; 82 } 83 } 84 // Called by fatal error handler. 85 void VM_Operation::print_on_error(outputStream* st) const { 86 st->print("VM_Operation (" PTR_FORMAT "): ", p2i(this)); 87 st->print("%s", name()); 88 89 const char* mode = mode_to_string(evaluation_mode()); 90 st->print(", mode: %s", mode); 91 92 if (calling_thread()) { 93 st->print(", requested by thread " PTR_FORMAT, p2i(calling_thread())); 94 } 95 } 96 97 void VM_ThreadStop::doit() { 98 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); 99 JavaThread* target = java_lang_Thread::thread(target_thread()); 100 // Note that this now allows multiple ThreadDeath exceptions to be 101 // thrown at a thread. 102 if (target != NULL) { 103 // the thread has run and is not already in the process of exiting 104 target->send_thread_stop(throwable()); 105 } 106 } 107 108 void VM_ClearICs::doit() { 109 if (_preserve_static_stubs) { 110 CodeCache::cleanup_inline_caches(); 111 } else { 112 CodeCache::clear_inline_caches(); 113 } 114 } 115 116 void VM_Deoptimize::doit() { 117 // We do not want any GCs to happen while we are in the middle of this VM operation 118 ResourceMark rm; 119 DeoptimizationMarker dm; 120 121 // Deoptimize all activations depending on marked nmethods 122 Deoptimization::deoptimize_dependents(); 123 124 // Make the dependent methods not entrant 125 CodeCache::make_marked_nmethods_not_entrant(); 126 } 127 128 void VM_MarkActiveNMethods::doit() { 129 NMethodSweeper::mark_active_nmethods(); 130 } 131 132 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) { 133 _thread = thread; 134 _id = id; 135 _reason = reason; 136 } 137 138 139 void VM_DeoptimizeFrame::doit() { 140 assert(_reason > Deoptimization::Reason_none && _reason < Deoptimization::Reason_LIMIT, "invalid deopt reason"); 141 Deoptimization::deoptimize_frame_internal(_thread, _id, (Deoptimization::DeoptReason)_reason); 142 } 143 144 145 #ifndef PRODUCT 146 147 void VM_DeoptimizeAll::doit() { 148 DeoptimizationMarker dm; 149 // deoptimize all java threads in the system 150 if (DeoptimizeALot) { 151 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 152 if (thread->has_last_Java_frame()) { 153 thread->deoptimize(); 154 } 155 } 156 } else if (DeoptimizeRandom) { 157 158 // Deoptimize some selected threads and frames 159 int tnum = os::random() & 0x3; 160 int fnum = os::random() & 0x3; 161 int tcount = 0; 162 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 163 if (thread->has_last_Java_frame()) { 164 if (tcount++ == tnum) { 165 tcount = 0; 166 int fcount = 0; 167 // Deoptimize some selected frames. 168 // Biased llocking wants a updated register map 169 for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) { 170 if (fst.current()->can_be_deoptimized()) { 171 if (fcount++ == fnum) { 172 fcount = 0; 173 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map()); 174 } 175 } 176 } 177 } 178 } 179 } 180 } 181 } 182 183 184 void VM_ZombieAll::doit() { 185 JavaThread *thread = (JavaThread *)calling_thread(); 186 assert(thread->is_Java_thread(), "must be a Java thread"); 187 thread->make_zombies(); 188 } 189 190 #endif // !PRODUCT 191 192 void VM_UnlinkSymbols::doit() { 193 JavaThread *thread = (JavaThread *)calling_thread(); 194 assert(thread->is_Java_thread(), "must be a Java thread"); 195 SymbolTable::unlink(); 196 } 197 198 void VM_Verify::doit() { 199 Universe::heap()->prepare_for_verify(); 200 Universe::verify(); 201 } 202 203 bool VM_PrintThreads::doit_prologue() { 204 // Make sure AbstractOwnableSynchronizer is loaded 205 JavaThread* jt = JavaThread::current(); 206 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt); 207 if (jt->has_pending_exception()) { 208 return false; 209 } 210 211 // Get Heap_lock if concurrent locks will be dumped 212 if (_print_concurrent_locks) { 213 Heap_lock->lock(); 214 } 215 return true; 216 } 217 218 void VM_PrintThreads::doit() { 219 Threads::print_on(_out, true, false, _print_concurrent_locks); 220 } 221 222 void VM_PrintThreads::doit_epilogue() { 223 if (_print_concurrent_locks) { 224 // Release Heap_lock 225 Heap_lock->unlock(); 226 } 227 } 228 229 void VM_PrintJNI::doit() { 230 JNIHandles::print_on(_out); 231 } 232 233 void VM_PrintMetadata::doit() { 234 MetaspaceAux::print_metadata_for_nmt(_out, _scale); 235 } 236 237 VM_FindDeadlocks::~VM_FindDeadlocks() { 238 if (_deadlocks != NULL) { 239 DeadlockCycle* cycle = _deadlocks; 240 while (cycle != NULL) { 241 DeadlockCycle* d = cycle; 242 cycle = cycle->next(); 243 delete d; 244 } 245 } 246 } 247 248 bool VM_FindDeadlocks::doit_prologue() { 249 if (_concurrent_locks) { 250 // Make sure AbstractOwnableSynchronizer is loaded 251 JavaThread* jt = JavaThread::current(); 252 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt); 253 if (jt->has_pending_exception()) { 254 return false; 255 } 256 } 257 258 return true; 259 } 260 261 void VM_FindDeadlocks::doit() { 262 _deadlocks = ThreadService::find_deadlocks_at_safepoint(_concurrent_locks); 263 if (_out != NULL) { 264 int num_deadlocks = 0; 265 for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) { 266 num_deadlocks++; 267 cycle->print_on(_out); 268 } 269 270 if (num_deadlocks == 1) { 271 _out->print_cr("\nFound 1 deadlock.\n"); 272 _out->flush(); 273 } else if (num_deadlocks > 1) { 274 _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks); 275 _out->flush(); 276 } 277 } 278 } 279 280 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result, 281 int max_depth, 282 bool with_locked_monitors, 283 bool with_locked_synchronizers) { 284 _result = result; 285 _num_threads = 0; // 0 indicates all threads 286 _threads = NULL; 287 _result = result; 288 _max_depth = max_depth; 289 _with_locked_monitors = with_locked_monitors; 290 _with_locked_synchronizers = with_locked_synchronizers; 291 } 292 293 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result, 294 GrowableArray<instanceHandle>* threads, 295 int num_threads, 296 int max_depth, 297 bool with_locked_monitors, 298 bool with_locked_synchronizers) { 299 _result = result; 300 _num_threads = num_threads; 301 _threads = threads; 302 _result = result; 303 _max_depth = max_depth; 304 _with_locked_monitors = with_locked_monitors; 305 _with_locked_synchronizers = with_locked_synchronizers; 306 } 307 308 bool VM_ThreadDump::doit_prologue() { 309 // Make sure AbstractOwnableSynchronizer is loaded 310 JavaThread* jt = JavaThread::current(); 311 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt); 312 if (jt->has_pending_exception()) { 313 return false; 314 } 315 316 if (_with_locked_synchronizers) { 317 // Acquire Heap_lock to dump concurrent locks 318 Heap_lock->lock(); 319 } 320 321 return true; 322 } 323 324 void VM_ThreadDump::doit_epilogue() { 325 if (_with_locked_synchronizers) { 326 // Release Heap_lock 327 Heap_lock->unlock(); 328 } 329 } 330 331 void VM_ThreadDump::doit() { 332 ResourceMark rm; 333 334 ConcurrentLocksDump concurrent_locks(true); 335 if (_with_locked_synchronizers) { 336 concurrent_locks.dump_at_safepoint(); 337 } 338 339 if (_num_threads == 0) { 340 // Snapshot all live threads 341 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) { 342 if (jt->is_exiting() || 343 jt->is_hidden_from_external_view()) { 344 // skip terminating threads and hidden threads 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 } else { 355 // Snapshot threads in the given _threads array 356 // A dummy snapshot is created if a thread doesn't exist 357 for (int i = 0; i < _num_threads; i++) { 358 instanceHandle th = _threads->at(i); 359 if (th() == NULL) { 360 // skip if the thread doesn't exist 361 // Add a dummy snapshot 362 _result->add_thread_snapshot(new ThreadSnapshot()); 363 continue; 364 } 365 366 // Dump thread stack only if the thread is alive and not exiting 367 // and not VM internal thread. 368 JavaThread* jt = java_lang_Thread::thread(th()); 369 if (jt == NULL || /* thread not alive */ 370 jt->is_exiting() || 371 jt->is_hidden_from_external_view()) { 372 // add a NULL snapshot if skipped 373 _result->add_thread_snapshot(new ThreadSnapshot()); 374 continue; 375 } 376 ThreadConcurrentLocks* tcl = NULL; 377 if (_with_locked_synchronizers) { 378 tcl = concurrent_locks.thread_concurrent_locks(jt); 379 } 380 ThreadSnapshot* ts = snapshot_thread(jt, tcl); 381 _result->add_thread_snapshot(ts); 382 } 383 } 384 } 385 386 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) { 387 ThreadSnapshot* snapshot = new ThreadSnapshot(java_thread); 388 snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors); 389 snapshot->set_concurrent_locks(tcl); 390 return snapshot; 391 } 392 393 volatile bool VM_Exit::_vm_exited = false; 394 Thread * VM_Exit::_shutdown_thread = NULL; 395 396 int VM_Exit::set_vm_exited() { 397 398 Thread * thr_cur = Thread::current(); 399 400 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already"); 401 402 int num_active = 0; 403 404 _shutdown_thread = thr_cur; 405 _vm_exited = true; // global flag 406 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) 407 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) { 408 ++num_active; 409 thr->set_terminated(JavaThread::_vm_exited); // per-thread flag 410 } 411 412 return num_active; 413 } 414 415 int VM_Exit::wait_for_threads_in_native_to_block() { 416 // VM exits at safepoint. This function must be called at the final safepoint 417 // to wait for threads in _thread_in_native state to be quiescent. 418 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already"); 419 420 Thread * thr_cur = Thread::current(); 421 Monitor timer(Mutex::leaf, "VM_Exit timer", true, 422 Monitor::_safepoint_check_never); 423 424 // Compiler threads need longer wait because they can access VM data directly 425 // while in native. If they are active and some structures being used are 426 // deleted by the shutdown sequence, they will crash. On the other hand, user 427 // threads must go through native=>Java/VM transitions first to access VM 428 // data, and they will be stopped during state transition. In theory, we 429 // don't have to wait for user threads to be quiescent, but it's always 430 // better to terminate VM when current thread is the only active thread, so 431 // wait for user threads too. Numbers are in 10 milliseconds. 432 int max_wait_user_thread = 30; // at least 300 milliseconds 433 int max_wait_compiler_thread = 1000; // at least 10 seconds 434 435 int max_wait = max_wait_compiler_thread; 436 437 int attempts = 0; 438 while (true) { 439 int num_active = 0; 440 int num_active_compiler_thread = 0; 441 442 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) { 443 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) { 444 num_active++; 445 if (thr->is_Compiler_thread()) { 446 num_active_compiler_thread++; 447 } 448 } 449 } 450 451 if (num_active == 0) { 452 return 0; 453 } else if (attempts > max_wait) { 454 return num_active; 455 } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) { 456 return num_active; 457 } 458 459 attempts++; 460 461 MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag); 462 timer.wait(Mutex::_no_safepoint_check_flag, 10); 463 } 464 } 465 466 void VM_Exit::doit() { 467 CompileBroker::set_should_block(); 468 469 // Wait for a short period for threads in native to block. Any thread 470 // still executing native code after the wait will be stopped at 471 // native==>Java/VM barriers. 472 // Among 16276 JCK tests, 94% of them come here without any threads still 473 // running in native; the other 6% are quiescent within 250ms (Ultra 80). 474 wait_for_threads_in_native_to_block(); 475 476 set_vm_exited(); 477 478 // cleanup globals resources before exiting. exit_globals() currently 479 // cleans up outputStream resources and PerfMemory resources. 480 exit_globals(); 481 482 // Check for exit hook 483 exit_hook_t exit_hook = Arguments::exit_hook(); 484 if (exit_hook != NULL) { 485 // exit hook should exit. 486 exit_hook(_exit_code); 487 // ... but if it didn't, we must do it here 488 vm_direct_exit(_exit_code); 489 } else { 490 vm_direct_exit(_exit_code); 491 } 492 } 493 494 495 void VM_Exit::wait_if_vm_exited() { 496 if (_vm_exited && 497 Thread::current_or_null() != _shutdown_thread) { 498 // _vm_exited is set at safepoint, and the Threads_lock is never released 499 // we will block here until the process dies 500 Threads_lock->lock_without_safepoint_check(); 501 ShouldNotReachHere(); 502 } 503 } 504 505 void VM_PrintCompileQueue::doit() { 506 CompileBroker::print_compile_queues(_out); 507 } 508 509 #if INCLUDE_SERVICES 510 void VM_PrintClassHierarchy::doit() { 511 KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname); 512 } 513 #endif