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