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
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  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.
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  23  */
  24 
  25 #ifndef SHARE_VM_RUNTIME_MUTEXLOCKER_HPP
  26 #define SHARE_VM_RUNTIME_MUTEXLOCKER_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "runtime/mutex.hpp"
  30 
  31 // Mutexes used in the VM.
  32 
  33 extern Mutex*   Patching_lock;                   // a lock used to guard code patching of compiled code
  34 extern Monitor* SystemDictionary_lock;           // a lock on the system dictionary
  35 extern Mutex*   PackageTable_lock;               // a lock on the class loader package table
  36 extern Mutex*   CompiledIC_lock;                 // a lock used to guard compiled IC patching and access
  37 extern Mutex*   InlineCacheBuffer_lock;          // a lock used to guard the InlineCacheBuffer
  38 extern Mutex*   VMStatistic_lock;                // a lock used to guard statistics count increment
  39 extern Mutex*   JNIGlobalHandle_lock;            // a lock on creating JNI global handles
  40 extern Mutex*   JNIHandleBlockFreeList_lock;     // a lock on the JNI handle block free list
  41 extern Mutex*   MemberNameTable_lock;            // a lock on the MemberNameTable updates
  42 extern Mutex*   JmethodIdCreation_lock;          // a lock on creating JNI method identifiers
  43 extern Mutex*   JfieldIdCreation_lock;           // a lock on creating JNI static field identifiers
  44 extern Monitor* JNICritical_lock;                // a lock used while entering and exiting JNI critical regions, allows GC to sometimes get in
  45 extern Mutex*   JvmtiThreadState_lock;           // a lock on modification of JVMTI thread data
  46 extern Monitor* JvmtiPendingEvent_lock;          // a lock on the JVMTI pending events list
  47 extern Monitor* Heap_lock;                       // a lock on the heap
  48 extern Mutex*   ExpandHeap_lock;                 // a lock on expanding the heap
  49 extern Mutex*   AdapterHandlerLibrary_lock;      // a lock on the AdapterHandlerLibrary
  50 extern Mutex*   SignatureHandlerLibrary_lock;    // a lock on the SignatureHandlerLibrary
  51 extern Mutex*   VtableStubs_lock;                // a lock on the VtableStubs
  52 extern Mutex*   SymbolTable_lock;                // a lock on the symbol table
  53 extern Mutex*   StringTable_lock;                // a lock on the interned string table
  54 extern Monitor* StringDedupQueue_lock;           // a lock on the string deduplication queue
  55 extern Mutex*   StringDedupTable_lock;           // a lock on the string deduplication table
  56 extern Mutex*   CodeCache_lock;                  // a lock on the CodeCache, rank is special, use MutexLockerEx
  57 extern Mutex*   MethodData_lock;                 // a lock on installation of method data
  58 extern Mutex*   RetData_lock;                    // a lock on installation of RetData inside method data
  59 extern Mutex*   DerivedPointerTableGC_lock;      // a lock to protect the derived pointer table
  60 extern Monitor* VMOperationQueue_lock;           // a lock on queue of vm_operations waiting to execute
  61 extern Monitor* VMOperationRequest_lock;         // a lock on Threads waiting for a vm_operation to terminate
  62 extern Monitor* Safepoint_lock;                  // a lock used by the safepoint abstraction
  63 extern Monitor* Threads_lock;                    // a lock on the Threads table of active Java threads
  64                                                  // (also used by Safepoints too to block threads creation/destruction)
  65 extern Monitor* CGC_lock;                        // used for coordination between
  66                                                  // fore- & background GC threads.
  67 extern Monitor* STS_lock;                        // used for joining/leaving SuspendibleThreadSet.
  68 extern Monitor* SLT_lock;                        // used in CMS GC for acquiring PLL
  69 extern Monitor* iCMS_lock;                       // CMS incremental mode start/stop notification
  70 extern Monitor* FullGCCount_lock;                // in support of "concurrent" full gc
  71 extern Monitor* CMark_lock;                      // used for concurrent mark thread coordination
  72 extern Mutex*   CMRegionStack_lock;              // used for protecting accesses to the CM region stack
  73 extern Mutex*   SATB_Q_FL_lock;                  // Protects SATB Q
  74                                                  // buffer free list.
  75 extern Monitor* SATB_Q_CBL_mon;                  // Protects SATB Q
  76                                                  // completed buffer queue.
  77 extern Mutex*   Shared_SATB_Q_lock;              // Lock protecting SATB
  78                                                  // queue shared by
  79                                                  // non-Java threads.
  80 
  81 extern Mutex*   DirtyCardQ_FL_lock;              // Protects dirty card Q
  82                                                  // buffer free list.
  83 extern Monitor* DirtyCardQ_CBL_mon;              // Protects dirty card Q
  84                                                  // completed buffer queue.
  85 extern Mutex*   Shared_DirtyCardQ_lock;          // Lock protecting dirty card
  86                                                  // queue shared by
  87                                                  // non-Java threads.
  88                                                  // (see option ExplicitGCInvokesConcurrent)
  89 extern Mutex*   ParGCRareEvent_lock;             // Synchronizes various (rare) parallel GC ops.
  90 extern Mutex*   EvacFailureStack_lock;           // guards the evac failure scan stack
  91 extern Mutex*   Compile_lock;                    // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
  92 extern Monitor* MethodCompileQueue_lock;         // a lock held when method compilations are enqueued, dequeued
  93 extern Monitor* CompileThread_lock;              // a lock held by compile threads during compilation system initialization
  94 extern Mutex*   CompileTaskAlloc_lock;           // a lock held when CompileTasks are allocated
  95 extern Mutex*   CompileStatistics_lock;          // a lock held when updating compilation statistics
  96 extern Mutex*   MultiArray_lock;                 // a lock used to guard allocation of multi-dim arrays
  97 extern Monitor* Terminator_lock;                 // a lock used to guard termination of the vm
  98 extern Monitor* BeforeExit_lock;                 // a lock used to guard cleanups and shutdown hooks
  99 extern Monitor* Notify_lock;                     // a lock used to synchronize the start-up of the vm
 100 extern Monitor* Interrupt_lock;                  // a lock used for condition variable mediated interrupt processing
 101 extern Monitor* ProfileVM_lock;                  // a lock used for profiling the VMThread
 102 extern Mutex*   ProfilePrint_lock;               // a lock used to serialize the printing of profiles
 103 extern Mutex*   ExceptionCache_lock;             // a lock used to synchronize exception cache updates
 104 extern Mutex*   OsrList_lock;                    // a lock used to serialize access to OSR queues
 105 
 106 #ifndef PRODUCT
 107 extern Mutex*   FullGCALot_lock;                 // a lock to make FullGCALot MT safe
 108 #endif // PRODUCT
 109 extern Mutex*   Debug1_lock;                     // A bunch of pre-allocated locks that can be used for tracing
 110 extern Mutex*   Debug2_lock;                     // down synchronization related bugs!
 111 extern Mutex*   Debug3_lock;
 112 
 113 extern Mutex*   RawMonitor_lock;
 114 extern Mutex*   PerfDataMemAlloc_lock;           // a lock on the allocator for PerfData memory for performance data
 115 extern Mutex*   PerfDataManager_lock;            // a long on access to PerfDataManager resources
 116 extern Mutex*   ParkerFreeList_lock;
 117 extern Mutex*   OopMapCacheAlloc_lock;           // protects allocation of oop_map caches
 118 
 119 extern Mutex*   FreeList_lock;                   // protects the free region list during safepoints
 120 extern Monitor* SecondaryFreeList_lock;          // protects the secondary free region list
 121 extern Mutex*   OldSets_lock;                    // protects the old region sets
 122 extern Monitor* RootRegionScan_lock;             // used to notify that the CM threads have finished scanning the IM snapshot regions
 123 extern Mutex*   MMUTracker_lock;                 // protects the MMU
 124                                                  // tracker data structures
 125 extern Mutex*   HotCardCache_lock;               // protects the hot card cache
 126 
 127 extern Mutex*   Management_lock;                 // a lock used to serialize JVM management
 128 extern Monitor* Service_lock;                    // a lock used for service thread operation
 129 extern Monitor* PeriodicTask_lock;               // protects the periodic task structure
 130 
 131 #ifdef INCLUDE_TRACE
 132 extern Mutex*   JfrStacktrace_lock;              // used to guard access to the JFR stacktrace table
 133 extern Monitor* JfrMsg_lock;                     // protects JFR messaging
 134 extern Mutex*   JfrBuffer_lock;                  // protects JFR buffer operations
 135 extern Mutex*   JfrStream_lock;                  // protects JFR stream access
 136 extern Mutex*   JfrThreadGroups_lock;            // protects JFR access to Thread Groups
 137 #endif
 138 
 139 // A MutexLocker provides mutual exclusion with respect to a given mutex
 140 // for the scope which contains the locker.  The lock is an OS lock, not
 141 // an object lock, and the two do not interoperate.  Do not use Mutex-based
 142 // locks to lock on Java objects, because they will not be respected if a
 143 // that object is locked using the Java locking mechanism.
 144 //
 145 //                NOTE WELL!!
 146 //
 147 // See orderAccess.hpp.  We assume throughout the VM that MutexLocker's
 148 // and friends constructors do a fence, a lock and an acquire *in that
 149 // order*.  And that their destructors do a release and unlock, in *that*
 150 // order.  If their implementations change such that these assumptions
 151 // are violated, a whole lot of code will break.
 152 
 153 // Print all mutexes/monitors that are currently owned by a thread; called
 154 // by fatal error handler.
 155 void print_owned_locks_on_error(outputStream* st);
 156 
 157 char *lock_name(Mutex *mutex);
 158 
 159 class MutexLocker: StackObj {
 160  private:
 161   Monitor * _mutex;
 162  public:
 163   MutexLocker(Monitor * mutex) {
 164     assert(mutex->rank() != Mutex::special,
 165       "Special ranked mutex should only use MutexLockerEx");
 166     _mutex = mutex;
 167     _mutex->lock();
 168   }
 169 
 170   // Overloaded constructor passing current thread
 171   MutexLocker(Monitor * mutex, Thread *thread) {
 172     assert(mutex->rank() != Mutex::special,
 173       "Special ranked mutex should only use MutexLockerEx");
 174     _mutex = mutex;
 175     _mutex->lock(thread);
 176   }
 177 
 178   ~MutexLocker() {
 179     _mutex->unlock();
 180   }
 181 
 182 };
 183 
 184 // for debugging: check that we're already owning this lock (or are at a safepoint)
 185 #ifdef ASSERT
 186 void assert_locked_or_safepoint(const Monitor * lock);
 187 void assert_lock_strong(const Monitor * lock);
 188 #else
 189 #define assert_locked_or_safepoint(lock)
 190 #define assert_lock_strong(lock)
 191 #endif
 192 
 193 // A MutexLockerEx behaves like a MutexLocker when its constructor is
 194 // called with a Mutex.  Unlike a MutexLocker, its constructor can also be
 195 // called with NULL, in which case the MutexLockerEx is a no-op.  There
 196 // is also a corresponding MutexUnlockerEx.  We want to keep the
 197 // basic MutexLocker as fast as possible.  MutexLockerEx can also lock
 198 // without safepoint check.
 199 
 200 class MutexLockerEx: public StackObj {
 201  private:
 202   Monitor * _mutex;
 203  public:
 204   MutexLockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
 205     _mutex = mutex;
 206     if (_mutex != NULL) {
 207       assert(mutex->rank() > Mutex::special || no_safepoint_check,
 208         "Mutexes with rank special or lower should not do safepoint checks");
 209       if (no_safepoint_check)
 210         _mutex->lock_without_safepoint_check();
 211       else
 212         _mutex->lock();
 213     }
 214   }
 215 
 216   ~MutexLockerEx() {
 217     if (_mutex != NULL) {
 218       _mutex->unlock();
 219     }
 220   }
 221 };
 222 
 223 // A MonitorLockerEx is like a MutexLockerEx above, except it takes
 224 // a possibly null Monitor, and allows wait/notify as well which are
 225 // delegated to the underlying Monitor.
 226 
 227 class MonitorLockerEx: public MutexLockerEx {
 228  private:
 229   Monitor * _monitor;
 230  public:
 231   MonitorLockerEx(Monitor* monitor,
 232                   bool no_safepoint_check = !Mutex::_no_safepoint_check_flag):
 233     MutexLockerEx(monitor, no_safepoint_check),
 234     _monitor(monitor) {
 235     // Superclass constructor did locking
 236   }
 237 
 238   ~MonitorLockerEx() {
 239     #ifdef ASSERT
 240       if (_monitor != NULL) {
 241         assert_lock_strong(_monitor);
 242       }
 243     #endif  // ASSERT
 244     // Superclass destructor will do unlocking
 245   }
 246 
 247   bool wait(bool no_safepoint_check = !Mutex::_no_safepoint_check_flag,
 248             long timeout = 0,
 249             bool as_suspend_equivalent = !Mutex::_as_suspend_equivalent_flag) {
 250     if (_monitor != NULL) {
 251       return _monitor->wait(no_safepoint_check, timeout, as_suspend_equivalent);
 252     }
 253     return false;
 254   }
 255 
 256   bool notify_all() {
 257     if (_monitor != NULL) {
 258       return _monitor->notify_all();
 259     }
 260     return true;
 261   }
 262 
 263   bool notify() {
 264     if (_monitor != NULL) {
 265       return _monitor->notify();
 266     }
 267     return true;
 268   }
 269 };
 270 
 271 
 272 
 273 // A GCMutexLocker is usually initialized with a mutex that is
 274 // automatically acquired in order to do GC.  The function that
 275 // synchronizes using a GCMutexLocker may be called both during and between
 276 // GC's.  Thus, it must acquire the mutex if GC is not in progress, but not
 277 // if GC is in progress (since the mutex is already held on its behalf.)
 278 
 279 class GCMutexLocker: public StackObj {
 280 private:
 281   Monitor * _mutex;
 282   bool _locked;
 283 public:
 284   GCMutexLocker(Monitor * mutex);
 285   ~GCMutexLocker() { if (_locked) _mutex->unlock(); }
 286 };
 287 
 288 
 289 
 290 // A MutexUnlocker temporarily exits a previously
 291 // entered mutex for the scope which contains the unlocker.
 292 
 293 class MutexUnlocker: StackObj {
 294  private:
 295   Monitor * _mutex;
 296 
 297  public:
 298   MutexUnlocker(Monitor * mutex) {
 299     _mutex = mutex;
 300     _mutex->unlock();
 301   }
 302 
 303   ~MutexUnlocker() {
 304     _mutex->lock();
 305   }
 306 };
 307 
 308 // A MutexUnlockerEx temporarily exits a previously
 309 // entered mutex for the scope which contains the unlocker.
 310 
 311 class MutexUnlockerEx: StackObj {
 312  private:
 313   Monitor * _mutex;
 314   bool _no_safepoint_check;
 315 
 316  public:
 317   MutexUnlockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
 318     _mutex = mutex;
 319     _no_safepoint_check = no_safepoint_check;
 320     _mutex->unlock();
 321   }
 322 
 323   ~MutexUnlockerEx() {
 324     if (_no_safepoint_check == Mutex::_no_safepoint_check_flag) {
 325       _mutex->lock_without_safepoint_check();
 326     } else {
 327       _mutex->lock();
 328     }
 329   }
 330 };
 331 
 332 #ifndef PRODUCT
 333 //
 334 // A special MutexLocker that allows:
 335 //   - reentrant locking
 336 //   - locking out of order
 337 //
 338 // Only to be used for verify code, where we can relax out dead-lock
 339 // detection code a bit (unsafe, but probably ok). This code is NEVER to
 340 // be included in a product version.
 341 //
 342 class VerifyMutexLocker: StackObj {
 343  private:
 344   Monitor * _mutex;
 345   bool   _reentrant;
 346  public:
 347   VerifyMutexLocker(Monitor * mutex) {
 348     _mutex     = mutex;
 349     _reentrant = mutex->owned_by_self();
 350     if (!_reentrant) {
 351       // We temp. disable strict safepoint checking, while we require the lock
 352       FlagSetting fs(StrictSafepointChecks, false);
 353       _mutex->lock();
 354     }
 355   }
 356 
 357   ~VerifyMutexLocker() {
 358     if (!_reentrant) {
 359       _mutex->unlock();
 360     }
 361   }
 362 };
 363 
 364 #endif
 365 
 366 #endif // SHARE_VM_RUNTIME_MUTEXLOCKER_HPP