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