1 /* 2 * Copyright (c) 1997, 2018, 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/frame.inline.hpp" 39 #include "runtime/interfaceSupport.inline.hpp" 40 #include "runtime/sweeper.hpp" 41 #include "runtime/thread.inline.hpp" 42 #include "runtime/threadSMR.inline.hpp" 43 #include "runtime/vm_operations.hpp" 44 #include "services/threadService.hpp" 45 #include "trace/tracing.hpp" 46 47 #define VM_OP_NAME_INITIALIZE(name) #name, 48 49 const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \ 50 { VM_OPS_DO(VM_OP_NAME_INITIALIZE) }; 51 52 void VM_Operation::set_calling_thread(Thread* thread, ThreadPriority priority) { 53 _calling_thread = thread; 54 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 55 _priority = priority; 56 } 57 58 59 void VM_Operation::evaluate() { 60 ResourceMark rm; 61 LogTarget(Debug, vmoperation) lt; 62 if (lt.is_enabled()) { 63 LogStream ls(lt); 64 ls.print("begin "); 65 print_on_error(&ls); 66 ls.cr(); 67 } 68 doit(); 69 if (lt.is_enabled()) { 70 LogStream ls(lt); 71 ls.print("end "); 72 print_on_error(&ls); 73 ls.cr(); 74 } 75 } 76 77 const char* VM_Operation::mode_to_string(Mode mode) { 78 switch(mode) { 79 case _safepoint : return "safepoint"; 80 case _no_safepoint : return "no safepoint"; 81 case _concurrent : return "concurrent"; 82 case _async_safepoint: return "async safepoint"; 83 default : return "unknown"; 84 } 85 } 86 // Called by fatal error handler. 87 void VM_Operation::print_on_error(outputStream* st) const { 88 st->print("VM_Operation (" PTR_FORMAT "): ", p2i(this)); 89 st->print("%s", name()); 90 91 const char* mode = mode_to_string(evaluation_mode()); 92 st->print(", mode: %s", mode); 93 94 if (calling_thread()) { 95 st->print(", requested by thread " PTR_FORMAT, p2i(calling_thread())); 96 } 97 } 98 99 void VM_ThreadStop::doit() { 100 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); 101 ThreadsListHandle tlh; 102 JavaThread* target = java_lang_Thread::thread(target_thread()); 103 // Note that this now allows multiple ThreadDeath exceptions to be 104 // thrown at a thread. 105 if (target != NULL && (!EnableThreadSMRExtraValidityChecks || tlh.includes(target))) { 106 // The target thread has run and has not exited yet. 107 target->send_thread_stop(throwable()); 108 } 109 } 110 111 void VM_ClearICs::doit() { 112 if (_preserve_static_stubs) { 113 CodeCache::cleanup_inline_caches(); 114 } else { 115 CodeCache::clear_inline_caches(); 116 } 117 } 118 119 void VM_Deoptimize::doit() { 120 // We do not want any GCs to happen while we are in the middle of this VM operation 121 ResourceMark rm; 122 DeoptimizationMarker dm; 123 124 // Deoptimize all activations depending on marked nmethods 125 Deoptimization::deoptimize_dependents(); 126 127 // Make the dependent methods not entrant 128 CodeCache::make_marked_nmethods_not_entrant(); 129 } 130 131 void VM_MarkActiveNMethods::doit() { 132 NMethodSweeper::mark_active_nmethods(); 133 } 134 135 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) { 136 _thread = thread; 137 _id = id; 138 _reason = reason; 139 } 140 141 142 void VM_DeoptimizeFrame::doit() { 143 assert(_reason > Deoptimization::Reason_none && _reason < Deoptimization::Reason_LIMIT, "invalid deopt reason"); 144 Deoptimization::deoptimize_frame_internal(_thread, _id, (Deoptimization::DeoptReason)_reason); 145 } 146 147 148 #ifndef PRODUCT 149 150 void VM_DeoptimizeAll::doit() { 151 DeoptimizationMarker dm; 152 JavaThreadIteratorWithHandle jtiwh; 153 // deoptimize all java threads in the system 154 if (DeoptimizeALot) { 155 for (; JavaThread *thread = jtiwh.next(); ) { 156 if (thread->has_last_Java_frame()) { 157 thread->deoptimize(); 158 } 159 } 160 } else if (DeoptimizeRandom) { 161 162 // Deoptimize some selected threads and frames 163 int tnum = os::random() & 0x3; 164 int fnum = os::random() & 0x3; 165 int tcount = 0; 166 for (; JavaThread *thread = jtiwh.next(); ) { 167 if (thread->has_last_Java_frame()) { 168 if (tcount++ == tnum) { 169 tcount = 0; 170 int fcount = 0; 171 // Deoptimize some selected frames. 172 // Biased llocking wants a updated register map 173 for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) { 174 if (fst.current()->can_be_deoptimized()) { 175 if (fcount++ == fnum) { 176 fcount = 0; 177 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map()); 178 } 179 } 180 } 181 } 182 } 183 } 184 } 185 } 186 187 188 void VM_ZombieAll::doit() { 189 JavaThread *thread = (JavaThread *)calling_thread(); 190 assert(thread->is_Java_thread(), "must be a Java thread"); 191 thread->make_zombies(); 192 } 193 194 #endif // !PRODUCT 195 196 void VM_UnlinkSymbols::doit() { 197 JavaThread *thread = (JavaThread *)calling_thread(); 198 assert(thread->is_Java_thread(), "must be a Java thread"); 199 SymbolTable::unlink(); 200 } 201 202 void VM_Verify::doit() { 203 Universe::heap()->prepare_for_verify(); 204 Universe::verify(); 205 } 206 207 bool VM_PrintThreads::doit_prologue() { 208 // Make sure AbstractOwnableSynchronizer is loaded 209 JavaThread* jt = JavaThread::current(); 210 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt); 211 if (jt->has_pending_exception()) { 212 return false; 213 } 214 215 // Get Heap_lock if concurrent locks will be dumped 216 if (_print_concurrent_locks) { 217 Heap_lock->lock(); 218 } 219 return true; 220 } 221 222 void VM_PrintThreads::doit() { 223 Threads::print_on(_out, true, false, _print_concurrent_locks); 224 } 225 226 void VM_PrintThreads::doit_epilogue() { 227 if (_print_concurrent_locks) { 228 // Release Heap_lock 229 Heap_lock->unlock(); 230 } 231 } 232 233 void VM_PrintJNI::doit() { 234 JNIHandles::print_on(_out); 235 } 236 237 void VM_PrintMetadata::doit() { 238 MetaspaceUtils::print_report(_out, _scale, _flags); 239 } 240 241 VM_FindDeadlocks::~VM_FindDeadlocks() { 242 if (_deadlocks != NULL) { 243 DeadlockCycle* cycle = _deadlocks; 244 while (cycle != NULL) { 245 DeadlockCycle* d = cycle; 246 cycle = cycle->next(); 247 delete d; 248 } 249 } 250 } 251 252 bool VM_FindDeadlocks::doit_prologue() { 253 if (_concurrent_locks) { 254 // Make sure AbstractOwnableSynchronizer is loaded 255 JavaThread* jt = JavaThread::current(); 256 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt); 257 if (jt->has_pending_exception()) { 258 return false; 259 } 260 } 261 262 return true; 263 } 264 265 void VM_FindDeadlocks::doit() { 266 // Update the hazard ptr in the originating thread to the current 267 // list of threads. This VM operation needs the current list of 268 // threads for proper deadlock detection and those are the 269 // JavaThreads we need to be protected when we return info to the 270 // originating thread. 271 _setter.set(); 272 273 _deadlocks = ThreadService::find_deadlocks_at_safepoint(_setter.list(), _concurrent_locks); 274 if (_out != NULL) { 275 int num_deadlocks = 0; 276 for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) { 277 num_deadlocks++; 278 cycle->print_on_with(_setter.list(), _out); 279 } 280 281 if (num_deadlocks == 1) { 282 _out->print_cr("\nFound 1 deadlock.\n"); 283 _out->flush(); 284 } else if (num_deadlocks > 1) { 285 _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks); 286 _out->flush(); 287 } 288 } 289 } 290 291 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result, 292 int max_depth, 293 bool with_locked_monitors, 294 bool with_locked_synchronizers) { 295 _result = result; 296 _num_threads = 0; // 0 indicates all threads 297 _threads = NULL; 298 _result = result; 299 _max_depth = max_depth; 300 _with_locked_monitors = with_locked_monitors; 301 _with_locked_synchronizers = with_locked_synchronizers; 302 } 303 304 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result, 305 GrowableArray<instanceHandle>* threads, 306 int num_threads, 307 int max_depth, 308 bool with_locked_monitors, 309 bool with_locked_synchronizers) { 310 _result = result; 311 _num_threads = num_threads; 312 _threads = threads; 313 _result = result; 314 _max_depth = max_depth; 315 _with_locked_monitors = with_locked_monitors; 316 _with_locked_synchronizers = with_locked_synchronizers; 317 } 318 319 bool VM_ThreadDump::doit_prologue() { 320 // Make sure AbstractOwnableSynchronizer is loaded 321 JavaThread* jt = JavaThread::current(); 322 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt); 323 if (jt->has_pending_exception()) { 324 return false; 325 } 326 327 if (_with_locked_synchronizers) { 328 // Acquire Heap_lock to dump concurrent locks 329 Heap_lock->lock(); 330 } 331 332 return true; 333 } 334 335 void VM_ThreadDump::doit_epilogue() { 336 if (_with_locked_synchronizers) { 337 // Release Heap_lock 338 Heap_lock->unlock(); 339 } 340 } 341 342 void VM_ThreadDump::doit() { 343 ResourceMark rm; 344 345 // Set the hazard ptr in the originating thread to protect the 346 // current list of threads. This VM operation needs the current list 347 // of threads for a proper dump and those are the JavaThreads we need 348 // to be protected when we return info to the originating thread. 349 _result->set_t_list(); 350 351 ConcurrentLocksDump concurrent_locks(true); 352 if (_with_locked_synchronizers) { 353 concurrent_locks.dump_at_safepoint(); 354 } 355 356 if (_num_threads == 0) { 357 // Snapshot all live threads 358 359 for (uint i = 0; i < _result->t_list()->length(); i++) { 360 JavaThread* jt = _result->t_list()->thread_at(i); 361 if (jt->is_exiting() || 362 jt->is_hidden_from_external_view()) { 363 // skip terminating threads and hidden threads 364 continue; 365 } 366 ThreadConcurrentLocks* tcl = NULL; 367 if (_with_locked_synchronizers) { 368 tcl = concurrent_locks.thread_concurrent_locks(jt); 369 } 370 ThreadSnapshot* ts = snapshot_thread(jt, tcl); 371 _result->add_thread_snapshot(ts); 372 } 373 } else { 374 // Snapshot threads in the given _threads array 375 // A dummy snapshot is created if a thread doesn't exist 376 377 for (int i = 0; i < _num_threads; i++) { 378 instanceHandle th = _threads->at(i); 379 if (th() == NULL) { 380 // skip if the thread doesn't exist 381 // Add a dummy snapshot 382 _result->add_thread_snapshot(new ThreadSnapshot()); 383 continue; 384 } 385 386 // Dump thread stack only if the thread is alive and not exiting 387 // and not VM internal thread. 388 JavaThread* jt = java_lang_Thread::thread(th()); 389 if (jt != NULL && !_result->t_list()->includes(jt)) { 390 // _threads[i] doesn't refer to a valid JavaThread; this check 391 // is primarily for JVM_DumpThreads() which doesn't have a good 392 // way to validate the _threads array. 393 jt = NULL; 394 } 395 if (jt == NULL || /* thread not alive */ 396 jt->is_exiting() || 397 jt->is_hidden_from_external_view()) { 398 // add a NULL snapshot if skipped 399 _result->add_thread_snapshot(new ThreadSnapshot()); 400 continue; 401 } 402 ThreadConcurrentLocks* tcl = NULL; 403 if (_with_locked_synchronizers) { 404 tcl = concurrent_locks.thread_concurrent_locks(jt); 405 } 406 ThreadSnapshot* ts = snapshot_thread(jt, tcl); 407 _result->add_thread_snapshot(ts); 408 } 409 } 410 } 411 412 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) { 413 ThreadSnapshot* snapshot = new ThreadSnapshot(_result->t_list(), java_thread); 414 snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors); 415 snapshot->set_concurrent_locks(tcl); 416 return snapshot; 417 } 418 419 volatile bool VM_Exit::_vm_exited = false; 420 Thread * volatile VM_Exit::_shutdown_thread = NULL; 421 422 int VM_Exit::set_vm_exited() { 423 424 Thread * thr_cur = Thread::current(); 425 426 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already"); 427 428 int num_active = 0; 429 430 _shutdown_thread = thr_cur; 431 _vm_exited = true; // global flag 432 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thr = jtiwh.next(); ) { 433 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) { 434 ++num_active; 435 thr->set_terminated(JavaThread::_vm_exited); // per-thread flag 436 } 437 } 438 439 return num_active; 440 } 441 442 int VM_Exit::wait_for_threads_in_native_to_block() { 443 // VM exits at safepoint. This function must be called at the final safepoint 444 // to wait for threads in _thread_in_native state to be quiescent. 445 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already"); 446 447 Thread * thr_cur = Thread::current(); 448 Monitor timer(Mutex::leaf, "VM_Exit timer", true, 449 Monitor::_safepoint_check_never); 450 451 // Compiler threads need longer wait because they can access VM data directly 452 // while in native. If they are active and some structures being used are 453 // deleted by the shutdown sequence, they will crash. On the other hand, user 454 // threads must go through native=>Java/VM transitions first to access VM 455 // data, and they will be stopped during state transition. In theory, we 456 // don't have to wait for user threads to be quiescent, but it's always 457 // better to terminate VM when current thread is the only active thread, so 458 // wait for user threads too. Numbers are in 10 milliseconds. 459 int max_wait_user_thread = 30; // at least 300 milliseconds 460 int max_wait_compiler_thread = 1000; // at least 10 seconds 461 462 int max_wait = max_wait_compiler_thread; 463 464 int attempts = 0; 465 JavaThreadIteratorWithHandle jtiwh; 466 while (true) { 467 int num_active = 0; 468 int num_active_compiler_thread = 0; 469 470 jtiwh.rewind(); 471 for (; JavaThread *thr = jtiwh.next(); ) { 472 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) { 473 num_active++; 474 if (thr->is_Compiler_thread()) { 475 num_active_compiler_thread++; 476 } 477 } 478 } 479 480 if (num_active == 0) { 481 return 0; 482 } else if (attempts > max_wait) { 483 return num_active; 484 } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) { 485 return num_active; 486 } 487 488 attempts++; 489 490 MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag); 491 timer.wait(Mutex::_no_safepoint_check_flag, 10); 492 } 493 } 494 495 void VM_Exit::doit() { 496 CompileBroker::set_should_block(); 497 498 // Wait for a short period for threads in native to block. Any thread 499 // still executing native code after the wait will be stopped at 500 // native==>Java/VM barriers. 501 // Among 16276 JCK tests, 94% of them come here without any threads still 502 // running in native; the other 6% are quiescent within 250ms (Ultra 80). 503 wait_for_threads_in_native_to_block(); 504 505 set_vm_exited(); 506 507 // cleanup globals resources before exiting. exit_globals() currently 508 // cleans up outputStream resources and PerfMemory resources. 509 exit_globals(); 510 511 // Check for exit hook 512 exit_hook_t exit_hook = Arguments::exit_hook(); 513 if (exit_hook != NULL) { 514 // exit hook should exit. 515 exit_hook(_exit_code); 516 // ... but if it didn't, we must do it here 517 vm_direct_exit(_exit_code); 518 } else { 519 vm_direct_exit(_exit_code); 520 } 521 } 522 523 524 void VM_Exit::wait_if_vm_exited() { 525 if (_vm_exited && 526 Thread::current_or_null() != _shutdown_thread) { 527 // _vm_exited is set at safepoint, and the Threads_lock is never released 528 // we will block here until the process dies 529 Threads_lock->lock_without_safepoint_check(); 530 ShouldNotReachHere(); 531 } 532 } 533 534 void VM_PrintCompileQueue::doit() { 535 CompileBroker::print_compile_queues(_out); 536 } 537 538 #if INCLUDE_SERVICES 539 void VM_PrintClassHierarchy::doit() { 540 KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname); 541 } 542 #endif