1 /*
   2  * Copyright (c) 1997, 2015, 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 "code/codeCacheExtensions.hpp"
  30 #include "compiler/compileBroker.hpp"
  31 #include "compiler/directivesparser.hpp"
  32 #include "gc/shared/isGCActiveMark.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 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  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   if (TraceVMOperation) {
  62     tty->print("[");
  63     NOT_PRODUCT(print();)
  64   }
  65   doit();
  66   if (TraceVMOperation) {
  67     tty->print_cr("]");
  68   }
  69 }
  70 
  71 const char* VM_Operation::mode_to_string(Mode mode) {
  72   switch(mode) {
  73     case _safepoint      : return "safepoint";
  74     case _no_safepoint   : return "no safepoint";
  75     case _concurrent     : return "concurrent";
  76     case _async_safepoint: return "async safepoint";
  77     default              : return "unknown";
  78   }
  79 }
  80 // Called by fatal error handler.
  81 void VM_Operation::print_on_error(outputStream* st) const {
  82   st->print("VM_Operation (" PTR_FORMAT "): ", this);
  83   st->print("%s", name());
  84 
  85   const char* mode = mode_to_string(evaluation_mode());
  86   st->print(", mode: %s", mode);
  87 
  88   if (calling_thread()) {
  89     st->print(", requested by thread " PTR_FORMAT, calling_thread());
  90   }
  91 }
  92 
  93 void VM_ThreadStop::doit() {
  94   assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
  95   JavaThread* target = java_lang_Thread::thread(target_thread());
  96   // Note that this now allows multiple ThreadDeath exceptions to be
  97   // thrown at a thread.
  98   if (target != NULL) {
  99     // the thread has run and is not already in the process of exiting
 100     target->send_thread_stop(throwable());
 101   }
 102 }
 103 
 104 void VM_Deoptimize::doit() {
 105   // We do not want any GCs to happen while we are in the middle of this VM operation
 106   ResourceMark rm;
 107   DeoptimizationMarker dm;
 108 
 109   // Deoptimize all activations depending on marked nmethods
 110   Deoptimization::deoptimize_dependents();
 111 
 112   // Make the dependent methods not entrant
 113   CodeCache::make_marked_nmethods_not_entrant();
 114 }
 115 
 116 void VM_MarkActiveNMethods::doit() {
 117   NMethodSweeper::mark_active_nmethods();
 118 }
 119 
 120 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id) {
 121   _thread = thread;
 122   _id     = id;
 123 }
 124 
 125 
 126 void VM_DeoptimizeFrame::doit() {
 127   Deoptimization::deoptimize_frame_internal(_thread, _id);
 128 }
 129 
 130 
 131 #ifndef PRODUCT
 132 
 133 void VM_DeoptimizeAll::doit() {
 134   DeoptimizationMarker dm;
 135   // deoptimize all java threads in the system
 136   if (DeoptimizeALot) {
 137     for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
 138       if (thread->has_last_Java_frame()) {
 139         thread->deoptimize();
 140       }
 141     }
 142   } else if (DeoptimizeRandom) {
 143 
 144     // Deoptimize some selected threads and frames
 145     int tnum = os::random() & 0x3;
 146     int fnum =  os::random() & 0x3;
 147     int tcount = 0;
 148     for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
 149       if (thread->has_last_Java_frame()) {
 150         if (tcount++ == tnum)  {
 151         tcount = 0;
 152           int fcount = 0;
 153           // Deoptimize some selected frames.
 154           // Biased llocking wants a updated register map
 155           for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {
 156             if (fst.current()->can_be_deoptimized()) {
 157               if (fcount++ == fnum) {
 158                 fcount = 0;
 159                 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());
 160               }
 161             }
 162           }
 163         }
 164       }
 165     }
 166   }
 167 }
 168 
 169 
 170 void VM_ZombieAll::doit() {
 171   JavaThread *thread = (JavaThread *)calling_thread();
 172   assert(thread->is_Java_thread(), "must be a Java thread");
 173   thread->make_zombies();
 174 }
 175 
 176 #endif // !PRODUCT
 177 
 178 void VM_UnlinkSymbols::doit() {
 179   JavaThread *thread = (JavaThread *)calling_thread();
 180   assert(thread->is_Java_thread(), "must be a Java thread");
 181   SymbolTable::unlink();
 182 }
 183 
 184 void VM_Verify::doit() {
 185   Universe::heap()->prepare_for_verify();
 186   Universe::verify(_silent);
 187 }
 188 
 189 bool VM_PrintThreads::doit_prologue() {
 190   assert(Thread::current()->is_Java_thread(), "just checking");
 191 
 192   // Make sure AbstractOwnableSynchronizer is loaded
 193   java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
 194 
 195   // Get Heap_lock if concurrent locks will be dumped
 196   if (_print_concurrent_locks) {
 197     Heap_lock->lock();
 198   }
 199   return true;
 200 }
 201 
 202 void VM_PrintThreads::doit() {
 203   Threads::print_on(_out, true, false, _print_concurrent_locks);
 204 }
 205 
 206 void VM_PrintThreads::doit_epilogue() {
 207   if (_print_concurrent_locks) {
 208     // Release Heap_lock
 209     Heap_lock->unlock();
 210   }
 211 }
 212 
 213 void VM_PrintJNI::doit() {
 214   JNIHandles::print_on(_out);
 215 }
 216 
 217 VM_FindDeadlocks::~VM_FindDeadlocks() {
 218   if (_deadlocks != NULL) {
 219     DeadlockCycle* cycle = _deadlocks;
 220     while (cycle != NULL) {
 221       DeadlockCycle* d = cycle;
 222       cycle = cycle->next();
 223       delete d;
 224     }
 225   }
 226 }
 227 
 228 bool VM_FindDeadlocks::doit_prologue() {
 229   assert(Thread::current()->is_Java_thread(), "just checking");
 230 
 231   // Load AbstractOwnableSynchronizer class
 232   if (_concurrent_locks) {
 233     java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
 234   }
 235 
 236   return true;
 237 }
 238 
 239 void VM_FindDeadlocks::doit() {
 240   _deadlocks = ThreadService::find_deadlocks_at_safepoint(_concurrent_locks);
 241   if (_out != NULL) {
 242     int num_deadlocks = 0;
 243     for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
 244       num_deadlocks++;
 245       cycle->print_on(_out);
 246     }
 247 
 248     if (num_deadlocks == 1) {
 249       _out->print_cr("\nFound 1 deadlock.\n");
 250       _out->flush();
 251     } else if (num_deadlocks > 1) {
 252       _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
 253       _out->flush();
 254     }
 255   }
 256 }
 257 
 258 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
 259                              int max_depth,
 260                              bool with_locked_monitors,
 261                              bool with_locked_synchronizers) {
 262   _result = result;
 263   _num_threads = 0; // 0 indicates all threads
 264   _threads = NULL;
 265   _result = result;
 266   _max_depth = max_depth;
 267   _with_locked_monitors = with_locked_monitors;
 268   _with_locked_synchronizers = with_locked_synchronizers;
 269 }
 270 
 271 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
 272                              GrowableArray<instanceHandle>* threads,
 273                              int num_threads,
 274                              int max_depth,
 275                              bool with_locked_monitors,
 276                              bool with_locked_synchronizers) {
 277   _result = result;
 278   _num_threads = num_threads;
 279   _threads = threads;
 280   _result = result;
 281   _max_depth = max_depth;
 282   _with_locked_monitors = with_locked_monitors;
 283   _with_locked_synchronizers = with_locked_synchronizers;
 284 }
 285 
 286 bool VM_ThreadDump::doit_prologue() {
 287   assert(Thread::current()->is_Java_thread(), "just checking");
 288 
 289   // Load AbstractOwnableSynchronizer class before taking thread snapshots
 290   java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
 291 
 292   if (_with_locked_synchronizers) {
 293     // Acquire Heap_lock to dump concurrent locks
 294     Heap_lock->lock();
 295   }
 296 
 297   return true;
 298 }
 299 
 300 void VM_ThreadDump::doit_epilogue() {
 301   if (_with_locked_synchronizers) {
 302     // Release Heap_lock
 303     Heap_lock->unlock();
 304   }
 305 }
 306 
 307 void VM_ThreadDump::doit() {
 308   ResourceMark rm;
 309 
 310   ConcurrentLocksDump concurrent_locks(true);
 311   if (_with_locked_synchronizers) {
 312     concurrent_locks.dump_at_safepoint();
 313   }
 314 
 315   if (_num_threads == 0) {
 316     // Snapshot all live threads
 317     for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
 318       if (jt->is_exiting() ||
 319           jt->is_hidden_from_external_view())  {
 320         // skip terminating threads and hidden threads
 321         continue;
 322       }
 323       ThreadConcurrentLocks* tcl = NULL;
 324       if (_with_locked_synchronizers) {
 325         tcl = concurrent_locks.thread_concurrent_locks(jt);
 326       }
 327       ThreadSnapshot* ts = snapshot_thread(jt, tcl);
 328       _result->add_thread_snapshot(ts);
 329     }
 330   } else {
 331     // Snapshot threads in the given _threads array
 332     // A dummy snapshot is created if a thread doesn't exist
 333     for (int i = 0; i < _num_threads; i++) {
 334       instanceHandle th = _threads->at(i);
 335       if (th() == NULL) {
 336         // skip if the thread doesn't exist
 337         // Add a dummy snapshot
 338         _result->add_thread_snapshot(new ThreadSnapshot());
 339         continue;
 340       }
 341 
 342       // Dump thread stack only if the thread is alive and not exiting
 343       // and not VM internal thread.
 344       JavaThread* jt = java_lang_Thread::thread(th());
 345       if (jt == NULL || /* thread not alive */
 346           jt->is_exiting() ||
 347           jt->is_hidden_from_external_view())  {
 348         // add a NULL snapshot if skipped
 349         _result->add_thread_snapshot(new ThreadSnapshot());
 350         continue;
 351       }
 352       ThreadConcurrentLocks* tcl = NULL;
 353       if (_with_locked_synchronizers) {
 354         tcl = concurrent_locks.thread_concurrent_locks(jt);
 355       }
 356       ThreadSnapshot* ts = snapshot_thread(jt, tcl);
 357       _result->add_thread_snapshot(ts);
 358     }
 359   }
 360 }
 361 
 362 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
 363   ThreadSnapshot* snapshot = new ThreadSnapshot(java_thread);
 364   snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
 365   snapshot->set_concurrent_locks(tcl);
 366   return snapshot;
 367 }
 368 
 369 volatile bool VM_Exit::_vm_exited = false;
 370 Thread * VM_Exit::_shutdown_thread = NULL;
 371 
 372 int VM_Exit::set_vm_exited() {
 373   CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::LastStep);
 374 
 375   Thread * thr_cur = ThreadLocalStorage::get_thread_slow();
 376 
 377   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
 378 
 379   int num_active = 0;
 380 
 381   _shutdown_thread = thr_cur;
 382   _vm_exited = true;                                // global flag
 383   for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next())
 384     if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
 385       ++num_active;
 386       thr->set_terminated(JavaThread::_vm_exited);  // per-thread flag
 387     }
 388 
 389   return num_active;
 390 }
 391 
 392 int VM_Exit::wait_for_threads_in_native_to_block() {
 393   // VM exits at safepoint. This function must be called at the final safepoint
 394   // to wait for threads in _thread_in_native state to be quiescent.
 395   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
 396 
 397   Thread * thr_cur = ThreadLocalStorage::get_thread_slow();
 398   Monitor timer(Mutex::leaf, "VM_Exit timer", true,
 399                 Monitor::_safepoint_check_never);
 400 
 401   // Compiler threads need longer wait because they can access VM data directly
 402   // while in native. If they are active and some structures being used are
 403   // deleted by the shutdown sequence, they will crash. On the other hand, user
 404   // threads must go through native=>Java/VM transitions first to access VM
 405   // data, and they will be stopped during state transition. In theory, we
 406   // don't have to wait for user threads to be quiescent, but it's always
 407   // better to terminate VM when current thread is the only active thread, so
 408   // wait for user threads too. Numbers are in 10 milliseconds.
 409   int max_wait_user_thread = 30;                  // at least 300 milliseconds
 410   int max_wait_compiler_thread = 1000;            // at least 10 seconds
 411 
 412   int max_wait = max_wait_compiler_thread;
 413 
 414   int attempts = 0;
 415   while (true) {
 416     int num_active = 0;
 417     int num_active_compiler_thread = 0;
 418 
 419     for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) {
 420       if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
 421         num_active++;
 422         if (thr->is_Compiler_thread()) {
 423           num_active_compiler_thread++;
 424         }
 425       }
 426     }
 427 
 428     if (num_active == 0) {
 429        return 0;
 430     } else if (attempts > max_wait) {
 431        return num_active;
 432     } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
 433        return num_active;
 434     }
 435 
 436     attempts++;
 437 
 438     MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag);
 439     timer.wait(Mutex::_no_safepoint_check_flag, 10);
 440   }
 441 }
 442 
 443 void VM_Exit::doit() {
 444   CompileBroker::set_should_block();
 445 
 446   // Wait for a short period for threads in native to block. Any thread
 447   // still executing native code after the wait will be stopped at
 448   // native==>Java/VM barriers.
 449   // Among 16276 JCK tests, 94% of them come here without any threads still
 450   // running in native; the other 6% are quiescent within 250ms (Ultra 80).
 451   wait_for_threads_in_native_to_block();
 452 
 453   set_vm_exited();
 454 
 455   // cleanup globals resources before exiting. exit_globals() currently
 456   // cleans up outputStream resources and PerfMemory resources.
 457   exit_globals();
 458 
 459   // Check for exit hook
 460   exit_hook_t exit_hook = Arguments::exit_hook();
 461   if (exit_hook != NULL) {
 462     // exit hook should exit.
 463     exit_hook(_exit_code);
 464     // ... but if it didn't, we must do it here
 465     vm_direct_exit(_exit_code);
 466   } else {
 467     vm_direct_exit(_exit_code);
 468   }
 469 }
 470 
 471 
 472 void VM_Exit::wait_if_vm_exited() {
 473   if (_vm_exited &&
 474       ThreadLocalStorage::get_thread_slow() != _shutdown_thread) {
 475     // _vm_exited is set at safepoint, and the Threads_lock is never released
 476     // we will block here until the process dies
 477     Threads_lock->lock_without_safepoint_check();
 478     ShouldNotReachHere();
 479   }
 480 }
 481 
 482 void VM_PrintCompileQueue::doit() {
 483   CompileBroker::print_compile_queues(_out);
 484 }
 485 
 486 void VM_PrintCodeList::doit() {
 487   CodeCache::print_codelist(_out);
 488 }
 489 
 490 void VM_PrintCodeCache::doit() {
 491   CodeCache::print_layout(_out);
 492 }
 493 
 494 #if INCLUDE_SERVICES
 495 void VM_PrintClassHierarchy::doit() {
 496   KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname);
 497 }
 498 #endif