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/threadSMR.inline.hpp" 42 #include "runtime/vm_operations.hpp" 43 #include "services/threadService.hpp" 44 #include "trace/tracing.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 VM_FindDeadlocks::~VM_FindDeadlocks() { 237 if (_deadlocks != NULL) { 238 DeadlockCycle* cycle = _deadlocks; 239 while (cycle != NULL) { 240 DeadlockCycle* d = cycle; 241 cycle = cycle->next(); 242 delete d; 243 } 244 } 245 } 246 247 bool VM_FindDeadlocks::doit_prologue() { 248 if (_concurrent_locks) { 249 // Make sure AbstractOwnableSynchronizer is loaded 250 JavaThread* jt = JavaThread::current(); 251 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt); 252 if (jt->has_pending_exception()) { 253 return false; 254 } 255 } 256 257 return true; 258 } 259 260 void VM_FindDeadlocks::doit() { 261 // Update the hazard ptr in the originating thread to the current 262 // list of threads. This VM operation needs the current list of 263 // threads for proper deadlock detection and those are the 264 // JavaThreads we need to be protected when we return info to the 265 // originating thread. 266 _setter.set(); 267 268 _deadlocks = ThreadService::find_deadlocks_at_safepoint(_setter.list(), _concurrent_locks); 269 if (_out != NULL) { 270 int num_deadlocks = 0; 271 for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) { 272 num_deadlocks++; 273 cycle->print_on_with(_setter.list(), _out); 274 } 275 276 if (num_deadlocks == 1) { 277 _out->print_cr("\nFound 1 deadlock.\n"); 278 _out->flush(); 279 } else if (num_deadlocks > 1) { 280 _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks); 281 _out->flush(); 282 } 283 } 284 } 285 286 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result, 287 int max_depth, 288 bool with_locked_monitors, 289 bool with_locked_synchronizers) { 290 _result = result; 291 _num_threads = 0; // 0 indicates all threads 292 _threads = NULL; 293 _result = result; 294 _max_depth = max_depth; 295 _with_locked_monitors = with_locked_monitors; 296 _with_locked_synchronizers = with_locked_synchronizers; 297 } 298 299 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result, 300 GrowableArray<instanceHandle>* threads, 301 int num_threads, 302 int max_depth, 303 bool with_locked_monitors, 304 bool with_locked_synchronizers) { 305 _result = result; 306 _num_threads = num_threads; 307 _threads = threads; 308 _result = result; 309 _max_depth = max_depth; 310 _with_locked_monitors = with_locked_monitors; 311 _with_locked_synchronizers = with_locked_synchronizers; 312 } 313 314 bool VM_ThreadDump::doit_prologue() { 315 // Make sure AbstractOwnableSynchronizer is loaded 316 JavaThread* jt = JavaThread::current(); 317 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt); 318 if (jt->has_pending_exception()) { 319 return false; 320 } 321 322 if (_with_locked_synchronizers) { 323 // Acquire Heap_lock to dump concurrent locks 324 Heap_lock->lock(); 325 } 326 327 return true; 328 } 329 330 void VM_ThreadDump::doit_epilogue() { 331 if (_with_locked_synchronizers) { 332 // Release Heap_lock 333 Heap_lock->unlock(); 334 } 335 } 336 337 void VM_ThreadDump::doit() { 338 ResourceMark rm; 339 340 // Set the hazard ptr in the originating thread to protect the 341 // current list of threads. This VM operation needs the current list 342 // of threads for a proper dump and those are the JavaThreads we need 343 // to be protected when we return info to the originating thread. 344 _result->set_t_list(); 345 346 ConcurrentLocksDump concurrent_locks(true); 347 if (_with_locked_synchronizers) { 348 concurrent_locks.dump_at_safepoint(); 349 } 350 351 if (_num_threads == 0) { 352 // Snapshot all live threads 353 354 for (uint i = 0; i < _result->t_list()->length(); i++) { 355 JavaThread* jt = _result->t_list()->thread_at(i); 356 if (jt->is_exiting() || 357 jt->is_hidden_from_external_view()) { 358 // skip terminating threads and hidden threads 359 continue; 360 } 361 ThreadConcurrentLocks* tcl = NULL; 362 if (_with_locked_synchronizers) { 363 tcl = concurrent_locks.thread_concurrent_locks(jt); 364 } 365 ThreadSnapshot* ts = snapshot_thread(jt, tcl); 366 _result->add_thread_snapshot(ts); 367 } 368 } else { 369 // Snapshot threads in the given _threads array 370 // A dummy snapshot is created if a thread doesn't exist 371 372 for (int i = 0; i < _num_threads; i++) { 373 instanceHandle th = _threads->at(i); 374 if (th() == NULL) { 375 // skip if the thread doesn't exist 376 // Add a dummy snapshot 377 _result->add_thread_snapshot(new ThreadSnapshot()); 378 continue; 379 } 380 381 // Dump thread stack only if the thread is alive and not exiting 382 // and not VM internal thread. 383 JavaThread* jt = java_lang_Thread::thread(th()); 384 if (jt != NULL && !_result->t_list()->includes(jt)) { 385 // _threads[i] doesn't refer to a valid JavaThread; this check 386 // is primarily for JVM_DumpThreads() which doesn't have a good 387 // way to validate the _threads array. 388 jt = NULL; 389 } 390 if (jt == NULL || /* thread not alive */ 391 jt->is_exiting() || 392 jt->is_hidden_from_external_view()) { 393 // add a NULL snapshot if skipped 394 _result->add_thread_snapshot(new ThreadSnapshot()); 395 continue; 396 } 397 ThreadConcurrentLocks* tcl = NULL; 398 if (_with_locked_synchronizers) { 399 tcl = concurrent_locks.thread_concurrent_locks(jt); 400 } 401 ThreadSnapshot* ts = snapshot_thread(jt, tcl); 402 _result->add_thread_snapshot(ts); 403 } 404 } 405 } 406 407 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) { 408 ThreadSnapshot* snapshot = new ThreadSnapshot(_result->t_list(), java_thread); 409 snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors); 410 snapshot->set_concurrent_locks(tcl); 411 return snapshot; 412 } 413 414 volatile bool VM_Exit::_vm_exited = false; 415 Thread * VM_Exit::_shutdown_thread = NULL; 416 417 int VM_Exit::set_vm_exited() { 418 419 Thread * thr_cur = Thread::current(); 420 421 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already"); 422 423 int num_active = 0; 424 425 _shutdown_thread = thr_cur; 426 _vm_exited = true; // global flag 427 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thr = jtiwh.next(); ) { 428 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) { 429 ++num_active; 430 thr->set_terminated(JavaThread::_vm_exited); // per-thread flag 431 } 432 } 433 434 return num_active; 435 } 436 437 int VM_Exit::wait_for_threads_in_native_to_block() { 438 // VM exits at safepoint. This function must be called at the final safepoint 439 // to wait for threads in _thread_in_native state to be quiescent. 440 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already"); 441 442 Thread * thr_cur = Thread::current(); 443 Monitor timer(Mutex::leaf, "VM_Exit timer", true, 444 Monitor::_safepoint_check_never); 445 446 // Compiler threads need longer wait because they can access VM data directly 447 // while in native. If they are active and some structures being used are 448 // deleted by the shutdown sequence, they will crash. On the other hand, user 449 // threads must go through native=>Java/VM transitions first to access VM 450 // data, and they will be stopped during state transition. In theory, we 451 // don't have to wait for user threads to be quiescent, but it's always 452 // better to terminate VM when current thread is the only active thread, so 453 // wait for user threads too. Numbers are in 10 milliseconds. 454 int max_wait_user_thread = 30; // at least 300 milliseconds 455 int max_wait_compiler_thread = 1000; // at least 10 seconds 456 457 int max_wait = max_wait_compiler_thread; 458 459 int attempts = 0; 460 JavaThreadIteratorWithHandle jtiwh; 461 while (true) { 462 int num_active = 0; 463 int num_active_compiler_thread = 0; 464 465 jtiwh.rewind(); 466 for (; JavaThread *thr = jtiwh.next(); ) { 467 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) { 468 num_active++; 469 if (thr->is_Compiler_thread()) { 470 num_active_compiler_thread++; 471 } 472 } 473 } 474 475 if (num_active == 0) { 476 return 0; 477 } else if (attempts > max_wait) { 478 return num_active; 479 } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) { 480 return num_active; 481 } 482 483 attempts++; 484 485 MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag); 486 timer.wait(Mutex::_no_safepoint_check_flag, 10); 487 } 488 } 489 490 void VM_Exit::doit() { 491 CompileBroker::set_should_block(); 492 493 // Wait for a short period for threads in native to block. Any thread 494 // still executing native code after the wait will be stopped at 495 // native==>Java/VM barriers. 496 // Among 16276 JCK tests, 94% of them come here without any threads still 497 // running in native; the other 6% are quiescent within 250ms (Ultra 80). 498 wait_for_threads_in_native_to_block(); 499 500 set_vm_exited(); 501 502 // cleanup globals resources before exiting. exit_globals() currently 503 // cleans up outputStream resources and PerfMemory resources. 504 exit_globals(); 505 506 // Check for exit hook 507 exit_hook_t exit_hook = Arguments::exit_hook(); 508 if (exit_hook != NULL) { 509 // exit hook should exit. 510 exit_hook(_exit_code); 511 // ... but if it didn't, we must do it here 512 vm_direct_exit(_exit_code); 513 } else { 514 vm_direct_exit(_exit_code); 515 } 516 } 517 518 519 void VM_Exit::wait_if_vm_exited() { 520 if (_vm_exited && 521 Thread::current_or_null() != _shutdown_thread) { 522 // _vm_exited is set at safepoint, and the Threads_lock is never released 523 // we will block here until the process dies 524 Threads_lock->lock_without_safepoint_check(); 525 ShouldNotReachHere(); 526 } 527 } 528 529 void VM_PrintCompileQueue::doit() { 530 CompileBroker::print_compile_queues(_out); 531 } 532 533 #if INCLUDE_SERVICES 534 void VM_PrintClassHierarchy::doit() { 535 KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname); 536 } 537 #endif