1 /*
   2  * Copyright (c) 1997, 2013, 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 "compiler/compileBroker.hpp"
  29 #include "compiler/compilerOracle.hpp"
  30 #include "gc_implementation/shared/isGCActiveMark.hpp"
  31 #include "memory/resourceArea.hpp"
  32 #include "oops/symbol.hpp"
  33 #include "runtime/arguments.hpp"
  34 #include "runtime/deoptimization.hpp"
  35 #include "runtime/interfaceSupport.hpp"
  36 #include "runtime/sweeper.hpp"
  37 #include "runtime/thread.inline.hpp"
  38 #include "runtime/vm_operations.hpp"
  39 #include "services/threadService.hpp"
  40 #include "trace/tracing.hpp"
  41 
  42 #define VM_OP_NAME_INITIALIZE(name) #name,
  43 
  44 const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \
  45   { VM_OPS_DO(VM_OP_NAME_INITIALIZE) };
  46 
  47 void VM_Operation::set_calling_thread(Thread* thread, ThreadPriority priority) {
  48   _calling_thread = thread;
  49   assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
  50   _priority = priority;
  51 }
  52 
  53 
  54 void VM_Operation::evaluate() {
  55   ResourceMark rm;
  56   if (TraceVMOperation) {
  57     tty->print("[");
  58     NOT_PRODUCT(print();)
  59   }
  60   doit();
  61   if (TraceVMOperation) {
  62     tty->print_cr("]");
  63   }
  64 }
  65 
  66 const char* VM_Operation::mode_to_string(Mode mode) {
  67   switch(mode) {
  68     case _safepoint      : return "safepoint";
  69     case _no_safepoint   : return "no safepoint";
  70     case _concurrent     : return "concurrent";
  71     case _async_safepoint: return "async safepoint";
  72     default              : return "unknown";
  73   }
  74 }
  75 // Called by fatal error handler.
  76 void VM_Operation::print_on_error(outputStream* st) const {
  77   st->print("VM_Operation (" PTR_FORMAT "): ", this);
  78   st->print("%s", name());
  79 
  80   const char* mode = mode_to_string(evaluation_mode());
  81   st->print(", mode: %s", mode);
  82 
  83   if (calling_thread()) {
  84     st->print(", requested by thread " PTR_FORMAT, calling_thread());
  85   }
  86 }
  87 
  88 void VM_ThreadStop::doit() {
  89   assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
  90   JavaThread* target = java_lang_Thread::thread(target_thread());
  91   // Note that this now allows multiple ThreadDeath exceptions to be
  92   // thrown at a thread.
  93   if (target != NULL) {
  94     // the thread has run and is not already in the process of exiting
  95     target->send_thread_stop(throwable());
  96   }
  97 }
  98 
  99 void VM_Deoptimize::doit() {
 100   // We do not want any GCs to happen while we are in the middle of this VM operation
 101   ResourceMark rm;
 102   DeoptimizationMarker dm;
 103 
 104   // Deoptimize all activations depending on marked nmethods
 105   Deoptimization::deoptimize_dependents();
 106 
 107   // Make the dependent methods zombies
 108   CodeCache::make_marked_nmethods_zombies();
 109 }
 110 
 111 
 112 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id) {
 113   _thread = thread;
 114   _id     = id;
 115 }
 116 
 117 
 118 void VM_DeoptimizeFrame::doit() {
 119   Deoptimization::deoptimize_frame_internal(_thread, _id);
 120 }
 121 
 122 
 123 #ifndef PRODUCT
 124 
 125 void VM_DeoptimizeAll::doit() {
 126   DeoptimizationMarker dm;
 127   // deoptimize all java threads in the system
 128   if (DeoptimizeALot) {
 129     for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
 130       if (thread->has_last_Java_frame()) {
 131         thread->deoptimize();
 132       }
 133     }
 134   } else if (DeoptimizeRandom) {
 135 
 136     // Deoptimize some selected threads and frames
 137     int tnum = os::random() & 0x3;
 138     int fnum =  os::random() & 0x3;
 139     int tcount = 0;
 140     for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
 141       if (thread->has_last_Java_frame()) {
 142         if (tcount++ == tnum)  {
 143         tcount = 0;
 144           int fcount = 0;
 145           // Deoptimize some selected frames.
 146           // Biased llocking wants a updated register map
 147           for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {
 148             if (fst.current()->can_be_deoptimized()) {
 149               if (fcount++ == fnum) {
 150                 fcount = 0;
 151                 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());
 152               }
 153             }
 154           }
 155         }
 156       }
 157     }
 158   }
 159 }
 160 
 161 
 162 void VM_ZombieAll::doit() {
 163   JavaThread *thread = (JavaThread *)calling_thread();
 164   assert(thread->is_Java_thread(), "must be a Java thread");
 165   thread->make_zombies();
 166 }
 167 
 168 #endif // !PRODUCT
 169 
 170 void VM_UnlinkSymbols::doit() {
 171   JavaThread *thread = (JavaThread *)calling_thread();
 172   assert(thread->is_Java_thread(), "must be a Java thread");
 173   SymbolTable::unlink();
 174 }
 175 
 176 void VM_Verify::doit() {
 177   Universe::heap()->prepare_for_verify();
 178   Universe::verify(_silent);
 179 }
 180 
 181 bool VM_PrintThreads::doit_prologue() {
 182   assert(Thread::current()->is_Java_thread(), "just checking");
 183 
 184   // Make sure AbstractOwnableSynchronizer is loaded
 185   if (JDK_Version::is_gte_jdk16x_version()) {
 186     java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
 187   }
 188 
 189   // Get Heap_lock if concurrent locks will be dumped
 190   if (_print_concurrent_locks) {
 191     Heap_lock->lock();
 192   }
 193   return true;
 194 }
 195 
 196 void VM_PrintThreads::doit() {
 197   Threads::print_on(_out, true, false, _print_concurrent_locks);
 198 }
 199 
 200 void VM_PrintThreads::doit_epilogue() {
 201   if (_print_concurrent_locks) {
 202     // Release Heap_lock
 203     Heap_lock->unlock();
 204   }
 205 }
 206 
 207 void VM_PrintJNI::doit() {
 208   JNIHandles::print_on(_out);
 209 }
 210 
 211 VM_FindDeadlocks::~VM_FindDeadlocks() {
 212   if (_deadlocks != NULL) {
 213     DeadlockCycle* cycle = _deadlocks;
 214     while (cycle != NULL) {
 215       DeadlockCycle* d = cycle;
 216       cycle = cycle->next();
 217       delete d;
 218     }
 219   }
 220 }
 221 
 222 bool VM_FindDeadlocks::doit_prologue() {
 223   assert(Thread::current()->is_Java_thread(), "just checking");
 224 
 225   // Load AbstractOwnableSynchronizer class
 226   if (_concurrent_locks && JDK_Version::is_gte_jdk16x_version()) {
 227     java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
 228   }
 229 
 230   return true;
 231 }
 232 
 233 void VM_FindDeadlocks::doit() {
 234   _deadlocks = ThreadService::find_deadlocks_at_safepoint(_concurrent_locks);
 235   if (_out != NULL) {
 236     int num_deadlocks = 0;
 237     for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
 238       num_deadlocks++;
 239       cycle->print_on(_out);
 240     }
 241 
 242     if (num_deadlocks == 1) {
 243       _out->print_cr("\nFound 1 deadlock.\n");
 244       _out->flush();
 245     } else if (num_deadlocks > 1) {
 246       _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
 247       _out->flush();
 248     }
 249   }
 250 }
 251 
 252 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
 253                              int max_depth,
 254                              bool with_locked_monitors,
 255                              bool with_locked_synchronizers) {
 256   _result = result;
 257   _num_threads = 0; // 0 indicates all threads
 258   _threads = NULL;
 259   _result = result;
 260   _max_depth = max_depth;
 261   _with_locked_monitors = with_locked_monitors;
 262   _with_locked_synchronizers = with_locked_synchronizers;
 263 }
 264 
 265 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
 266                              GrowableArray<instanceHandle>* threads,
 267                              int num_threads,
 268                              int max_depth,
 269                              bool with_locked_monitors,
 270                              bool with_locked_synchronizers) {
 271   _result = result;
 272   _num_threads = num_threads;
 273   _threads = threads;
 274   _result = result;
 275   _max_depth = max_depth;
 276   _with_locked_monitors = with_locked_monitors;
 277   _with_locked_synchronizers = with_locked_synchronizers;
 278 }
 279 
 280 bool VM_ThreadDump::doit_prologue() {
 281   assert(Thread::current()->is_Java_thread(), "just checking");
 282 
 283   // Load AbstractOwnableSynchronizer class before taking thread snapshots
 284   if (JDK_Version::is_gte_jdk16x_version()) {
 285     java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
 286   }
 287 
 288   if (_with_locked_synchronizers) {
 289     // Acquire Heap_lock to dump concurrent locks
 290     Heap_lock->lock();
 291   }
 292 
 293   return true;
 294 }
 295 
 296 void VM_ThreadDump::doit_epilogue() {
 297   if (_with_locked_synchronizers) {
 298     // Release Heap_lock
 299     Heap_lock->unlock();
 300   }
 301 }
 302 
 303 void VM_ThreadDump::doit() {
 304   ResourceMark rm;
 305 
 306   ConcurrentLocksDump concurrent_locks(true);
 307   if (_with_locked_synchronizers) {
 308     concurrent_locks.dump_at_safepoint();
 309   }
 310 
 311   if (_num_threads == 0) {
 312     // Snapshot all live threads
 313     for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
 314       if (jt->is_exiting() ||
 315           jt->is_hidden_from_external_view())  {
 316         // skip terminating threads and hidden threads
 317         continue;
 318       }
 319       ThreadConcurrentLocks* tcl = NULL;
 320       if (_with_locked_synchronizers) {
 321         tcl = concurrent_locks.thread_concurrent_locks(jt);
 322       }
 323       ThreadSnapshot* ts = snapshot_thread(jt, tcl);
 324       _result->add_thread_snapshot(ts);
 325     }
 326   } else {
 327     // Snapshot threads in the given _threads array
 328     // A dummy snapshot is created if a thread doesn't exist
 329     for (int i = 0; i < _num_threads; i++) {
 330       instanceHandle th = _threads->at(i);
 331       if (th() == NULL) {
 332         // skip if the thread doesn't exist
 333         // Add a dummy snapshot
 334         _result->add_thread_snapshot(new ThreadSnapshot());
 335         continue;
 336       }
 337 
 338       // Dump thread stack only if the thread is alive and not exiting
 339       // and not VM internal thread.
 340       JavaThread* jt = java_lang_Thread::thread(th());
 341       if (jt == NULL || /* thread not alive */
 342           jt->is_exiting() ||
 343           jt->is_hidden_from_external_view())  {
 344         // add a NULL snapshot if skipped
 345         _result->add_thread_snapshot(new ThreadSnapshot());
 346         continue;
 347       }
 348       ThreadConcurrentLocks* tcl = NULL;
 349       if (_with_locked_synchronizers) {
 350         tcl = concurrent_locks.thread_concurrent_locks(jt);
 351       }
 352       ThreadSnapshot* ts = snapshot_thread(jt, tcl);
 353       _result->add_thread_snapshot(ts);
 354     }
 355   }
 356 }
 357 
 358 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
 359   ThreadSnapshot* snapshot = new ThreadSnapshot(java_thread);
 360   snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
 361   snapshot->set_concurrent_locks(tcl);
 362   return snapshot;
 363 }
 364 
 365 volatile bool VM_Exit::_vm_exited = false;
 366 Thread * VM_Exit::_shutdown_thread = NULL;
 367 
 368 int VM_Exit::set_vm_exited() {
 369   Thread * thr_cur = ThreadLocalStorage::get_thread_slow();
 370 
 371   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
 372 
 373   int num_active = 0;
 374 
 375   _shutdown_thread = thr_cur;
 376   _vm_exited = true;                                // global flag
 377   for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next())
 378     if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
 379       ++num_active;
 380       thr->set_terminated(JavaThread::_vm_exited);  // per-thread flag
 381     }
 382 
 383   return num_active;
 384 }
 385 
 386 int VM_Exit::wait_for_threads_in_native_to_block() {
 387   // VM exits at safepoint. This function must be called at the final safepoint
 388   // to wait for threads in _thread_in_native state to be quiescent.
 389   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
 390 
 391   Thread * thr_cur = ThreadLocalStorage::get_thread_slow();
 392   Monitor timer(Mutex::leaf, "VM_Exit timer", true);
 393 
 394   // Compiler threads need longer wait because they can access VM data directly
 395   // while in native. If they are active and some structures being used are
 396   // deleted by the shutdown sequence, they will crash. On the other hand, user
 397   // threads must go through native=>Java/VM transitions first to access VM
 398   // data, and they will be stopped during state transition. In theory, we
 399   // don't have to wait for user threads to be quiescent, but it's always
 400   // better to terminate VM when current thread is the only active thread, so
 401   // wait for user threads too. Numbers are in 10 milliseconds.
 402   int max_wait_user_thread = 30;                  // at least 300 milliseconds
 403   int max_wait_compiler_thread = 1000;            // at least 10 seconds
 404 
 405   int max_wait = max_wait_compiler_thread;
 406 
 407   int attempts = 0;
 408   while (true) {
 409     int num_active = 0;
 410     int num_active_compiler_thread = 0;
 411 
 412     for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) {
 413       if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
 414         num_active++;
 415         if (thr->is_Compiler_thread()) {
 416           num_active_compiler_thread++;
 417         }
 418       }
 419     }
 420 
 421     if (num_active == 0) {
 422        return 0;
 423     } else if (attempts > max_wait) {
 424        return num_active;
 425     } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
 426        return num_active;
 427     }
 428 
 429     attempts++;
 430 
 431     MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag);
 432     timer.wait(Mutex::_no_safepoint_check_flag, 10);
 433   }
 434 }
 435 
 436 void VM_Exit::doit() {
 437   CompileBroker::set_should_block();
 438 
 439   // Wait for a short period for threads in native to block. Any thread
 440   // still executing native code after the wait will be stopped at
 441   // native==>Java/VM barriers.
 442   // Among 16276 JCK tests, 94% of them come here without any threads still
 443   // running in native; the other 6% are quiescent within 250ms (Ultra 80).
 444   wait_for_threads_in_native_to_block();
 445 
 446   set_vm_exited();
 447 
 448   // cleanup globals resources before exiting. exit_globals() currently
 449   // cleans up outputStream resources and PerfMemory resources.
 450   exit_globals();
 451 
 452   // Check for exit hook
 453   exit_hook_t exit_hook = Arguments::exit_hook();
 454   if (exit_hook != NULL) {
 455     // exit hook should exit.
 456     exit_hook(_exit_code);
 457     // ... but if it didn't, we must do it here
 458     vm_direct_exit(_exit_code);
 459   } else {
 460     vm_direct_exit(_exit_code);
 461   }
 462 }
 463 
 464 
 465 void VM_Exit::wait_if_vm_exited() {
 466   if (_vm_exited &&
 467       ThreadLocalStorage::get_thread_slow() != _shutdown_thread) {
 468     // _vm_exited is set at safepoint, and the Threads_lock is never released
 469     // we will block here until the process dies
 470     Threads_lock->lock_without_safepoint_check();
 471     ShouldNotReachHere();
 472   }
 473 }