1 /*
   2  * Copyright (c) 1997, 2014, 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 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  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 "): ", 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, 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 
 114 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id) {
 115   _thread = thread;
 116   _id     = id;
 117 }
 118 
 119 
 120 void VM_DeoptimizeFrame::doit() {
 121   Deoptimization::deoptimize_frame_internal(_thread, _id);
 122 }
 123 
 124 
 125 #ifndef PRODUCT
 126 
 127 void VM_DeoptimizeAll::doit() {
 128   DeoptimizationMarker dm;
 129   // deoptimize all java threads in the system
 130   if (DeoptimizeALot) {
 131     for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
 132       if (thread->has_last_Java_frame()) {
 133         thread->deoptimize();
 134       }
 135     }
 136   } else if (DeoptimizeRandom) {
 137 
 138     // Deoptimize some selected threads and frames
 139     int tnum = os::random() & 0x3;
 140     int fnum =  os::random() & 0x3;
 141     int tcount = 0;
 142     for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
 143       if (thread->has_last_Java_frame()) {
 144         if (tcount++ == tnum)  {
 145         tcount = 0;
 146           int fcount = 0;
 147           // Deoptimize some selected frames.
 148           // Biased llocking wants a updated register map
 149           for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {
 150             if (fst.current()->can_be_deoptimized()) {
 151               if (fcount++ == fnum) {
 152                 fcount = 0;
 153                 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());
 154               }
 155             }
 156           }
 157         }
 158       }
 159     }
 160   }
 161 }
 162 
 163 
 164 void VM_ZombieAll::doit() {
 165   JavaThread *thread = (JavaThread *)calling_thread();
 166   assert(thread->is_Java_thread(), "must be a Java thread");
 167   thread->make_zombies();
 168 }
 169 
 170 #endif // !PRODUCT
 171 
 172 void VM_UnlinkSymbols::doit() {
 173   JavaThread *thread = (JavaThread *)calling_thread();
 174   assert(thread->is_Java_thread(), "must be a Java thread");
 175   SymbolTable::unlink();
 176 }
 177 
 178 void VM_Verify::doit() {
 179   Universe::heap()->prepare_for_verify();
 180   Universe::verify(_silent);
 181 }
 182 
 183 bool VM_PrintThreads::doit_prologue() {
 184   assert(Thread::current()->is_Java_thread(), "just checking");
 185 
 186   // Make sure AbstractOwnableSynchronizer is loaded
 187   if (JDK_Version::is_gte_jdk16x_version()) {
 188     java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
 189   }
 190 
 191   // Get Heap_lock if concurrent locks will be dumped
 192   if (_print_concurrent_locks) {
 193     Heap_lock->lock();
 194   }
 195   return true;
 196 }
 197 
 198 void VM_PrintThreads::doit() {
 199   Threads::print_on(_out, true, false, _print_concurrent_locks);
 200 }
 201 
 202 void VM_PrintThreads::doit_epilogue() {
 203   if (_print_concurrent_locks) {
 204     // Release Heap_lock
 205     Heap_lock->unlock();
 206   }
 207 }
 208 
 209 void VM_PrintJNI::doit() {
 210   JNIHandles::print_on(_out);
 211 }
 212 
 213 VM_FindDeadlocks::~VM_FindDeadlocks() {
 214   if (_deadlocks != NULL) {
 215     DeadlockCycle* cycle = _deadlocks;
 216     while (cycle != NULL) {
 217       DeadlockCycle* d = cycle;
 218       cycle = cycle->next();
 219       delete d;
 220     }
 221   }
 222 }
 223 
 224 bool VM_FindDeadlocks::doit_prologue() {
 225   assert(Thread::current()->is_Java_thread(), "just checking");
 226 
 227   // Load AbstractOwnableSynchronizer class
 228   if (_concurrent_locks && JDK_Version::is_gte_jdk16x_version()) {
 229     java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
 230   }
 231 
 232   return true;
 233 }
 234 
 235 void VM_FindDeadlocks::doit() {
 236   _deadlocks = ThreadService::find_deadlocks_at_safepoint(_concurrent_locks);
 237   if (_out != NULL) {
 238     int num_deadlocks = 0;
 239     for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
 240       num_deadlocks++;
 241       cycle->print_on(_out);
 242     }
 243 
 244     if (num_deadlocks == 1) {
 245       _out->print_cr("\nFound 1 deadlock.\n");
 246       _out->flush();
 247     } else if (num_deadlocks > 1) {
 248       _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
 249       _out->flush();
 250     }
 251   }
 252 }
 253 
 254 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
 255                              int max_depth,
 256                              bool with_locked_monitors,
 257                              bool with_locked_synchronizers) {
 258   _result = result;
 259   _num_threads = 0; // 0 indicates all threads
 260   _threads = NULL;
 261   _result = result;
 262   _max_depth = max_depth;
 263   _with_locked_monitors = with_locked_monitors;
 264   _with_locked_synchronizers = with_locked_synchronizers;
 265 }
 266 
 267 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
 268                              GrowableArray<instanceHandle>* threads,
 269                              int num_threads,
 270                              int max_depth,
 271                              bool with_locked_monitors,
 272                              bool with_locked_synchronizers) {
 273   _result = result;
 274   _num_threads = num_threads;
 275   _threads = threads;
 276   _result = result;
 277   _max_depth = max_depth;
 278   _with_locked_monitors = with_locked_monitors;
 279   _with_locked_synchronizers = with_locked_synchronizers;
 280 }
 281 
 282 bool VM_ThreadDump::doit_prologue() {
 283   assert(Thread::current()->is_Java_thread(), "just checking");
 284 
 285   // Load AbstractOwnableSynchronizer class before taking thread snapshots
 286   if (JDK_Version::is_gte_jdk16x_version()) {
 287     java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
 288   }
 289 
 290   if (_with_locked_synchronizers) {
 291     // Acquire Heap_lock to dump concurrent locks
 292     Heap_lock->lock();
 293   }
 294 
 295   return true;
 296 }
 297 
 298 void VM_ThreadDump::doit_epilogue() {
 299   if (_with_locked_synchronizers) {
 300     // Release Heap_lock
 301     Heap_lock->unlock();
 302   }
 303 }
 304 
 305 void VM_ThreadDump::doit() {
 306   ResourceMark rm;
 307 
 308   ConcurrentLocksDump concurrent_locks(true);
 309   if (_with_locked_synchronizers) {
 310     concurrent_locks.dump_at_safepoint();
 311   }
 312 
 313   if (_num_threads == 0) {
 314     // Snapshot all live threads
 315     for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
 316       if (jt->is_exiting() ||
 317           jt->is_hidden_from_external_view())  {
 318         // skip terminating threads and hidden threads
 319         continue;
 320       }
 321       ThreadConcurrentLocks* tcl = NULL;
 322       if (_with_locked_synchronizers) {
 323         tcl = concurrent_locks.thread_concurrent_locks(jt);
 324       }
 325       ThreadSnapshot* ts = snapshot_thread(jt, tcl);
 326       _result->add_thread_snapshot(ts);
 327     }
 328   } else {
 329     // Snapshot threads in the given _threads array
 330     // A dummy snapshot is created if a thread doesn't exist
 331     for (int i = 0; i < _num_threads; i++) {
 332       instanceHandle th = _threads->at(i);
 333       if (th() == NULL) {
 334         // skip if the thread doesn't exist
 335         // Add a dummy snapshot
 336         _result->add_thread_snapshot(new ThreadSnapshot());
 337         continue;
 338       }
 339 
 340       // Dump thread stack only if the thread is alive and not exiting
 341       // and not VM internal thread.
 342       JavaThread* jt = java_lang_Thread::thread(th());
 343       if (jt == NULL || /* thread not alive */
 344           jt->is_exiting() ||
 345           jt->is_hidden_from_external_view())  {
 346         // add a NULL snapshot if skipped
 347         _result->add_thread_snapshot(new ThreadSnapshot());
 348         continue;
 349       }
 350       ThreadConcurrentLocks* tcl = NULL;
 351       if (_with_locked_synchronizers) {
 352         tcl = concurrent_locks.thread_concurrent_locks(jt);
 353       }
 354       ThreadSnapshot* ts = snapshot_thread(jt, tcl);
 355       _result->add_thread_snapshot(ts);
 356     }
 357   }
 358 }
 359 
 360 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
 361   ThreadSnapshot* snapshot = new ThreadSnapshot(java_thread);
 362   snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
 363   snapshot->set_concurrent_locks(tcl);
 364   return snapshot;
 365 }
 366 
 367 volatile bool VM_Exit::_vm_exited = false;
 368 Thread * VM_Exit::_shutdown_thread = NULL;
 369 
 370 int VM_Exit::set_vm_exited() {
 371   Thread * thr_cur = ThreadLocalStorage::get_thread_slow();
 372 
 373   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
 374 
 375   int num_active = 0;
 376 
 377   _shutdown_thread = thr_cur;
 378   _vm_exited = true;                                // global flag
 379   for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next())
 380     if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
 381       ++num_active;
 382       thr->set_terminated(JavaThread::_vm_exited);  // per-thread flag
 383     }
 384 
 385   return num_active;
 386 }
 387 
 388 int VM_Exit::wait_for_threads_in_native_to_block() {
 389   // VM exits at safepoint. This function must be called at the final safepoint
 390   // to wait for threads in _thread_in_native state to be quiescent.
 391   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
 392 
 393   Thread * thr_cur = ThreadLocalStorage::get_thread_slow();
 394   Monitor timer(Mutex::leaf, "VM_Exit timer", true);
 395 
 396   // Compiler threads need longer wait because they can access VM data directly
 397   // while in native. If they are active and some structures being used are
 398   // deleted by the shutdown sequence, they will crash. On the other hand, user
 399   // threads must go through native=>Java/VM transitions first to access VM
 400   // data, and they will be stopped during state transition. In theory, we
 401   // don't have to wait for user threads to be quiescent, but it's always
 402   // better to terminate VM when current thread is the only active thread, so
 403   // wait for user threads too. Numbers are in 10 milliseconds.
 404   int max_wait_user_thread = 30;                  // at least 300 milliseconds
 405   int max_wait_compiler_thread = 1000;            // at least 10 seconds
 406 
 407   int max_wait = max_wait_compiler_thread;
 408 
 409   int attempts = 0;
 410   while (true) {
 411     int num_active = 0;
 412     int num_active_compiler_thread = 0;
 413 
 414     for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) {
 415       if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
 416         num_active++;
 417         if (thr->is_Compiler_thread()) {
 418           num_active_compiler_thread++;
 419         }
 420       }
 421     }
 422 
 423     if (num_active == 0) {
 424        return 0;
 425     } else if (attempts > max_wait) {
 426        return num_active;
 427     } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
 428        return num_active;
 429     }
 430 
 431     attempts++;
 432 
 433     MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag);
 434     timer.wait(Mutex::_no_safepoint_check_flag, 10);
 435   }
 436 }
 437 
 438 void VM_Exit::doit() {
 439   CompileBroker::set_should_block();
 440 
 441   // Wait for a short period for threads in native to block. Any thread
 442   // still executing native code after the wait will be stopped at
 443   // native==>Java/VM barriers.
 444   // Among 16276 JCK tests, 94% of them come here without any threads still
 445   // running in native; the other 6% are quiescent within 250ms (Ultra 80).
 446   wait_for_threads_in_native_to_block();
 447 
 448   set_vm_exited();
 449 
 450   // cleanup globals resources before exiting. exit_globals() currently
 451   // cleans up outputStream resources and PerfMemory resources.
 452   exit_globals();
 453 
 454   // Check for exit hook
 455   exit_hook_t exit_hook = Arguments::exit_hook();
 456   if (exit_hook != NULL) {
 457     // exit hook should exit.
 458     exit_hook(_exit_code);
 459     // ... but if it didn't, we must do it here
 460     vm_direct_exit(_exit_code);
 461   } else {
 462     vm_direct_exit(_exit_code);
 463   }
 464 }
 465 
 466 
 467 void VM_Exit::wait_if_vm_exited() {
 468   if (_vm_exited &&
 469       ThreadLocalStorage::get_thread_slow() != _shutdown_thread) {
 470     // _vm_exited is set at safepoint, and the Threads_lock is never released
 471     // we will block here until the process dies
 472     Threads_lock->lock_without_safepoint_check();
 473     ShouldNotReachHere();
 474   }
 475 }