1 /*
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   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
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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*   Module_lock;                     // a lock on module and package related data structures
  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*   ResolvedMethodTable_lock;        // a lock on the ResolvedMethodTable 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* Heap_lock;                       // a lock on the heap
  47 extern Mutex*   ExpandHeap_lock;                 // a lock on expanding the heap
  48 extern Mutex*   AdapterHandlerLibrary_lock;      // a lock on the AdapterHandlerLibrary
  49 extern Mutex*   SignatureHandlerLibrary_lock;    // a lock on the SignatureHandlerLibrary
  50 extern Mutex*   VtableStubs_lock;                // a lock on the VtableStubs
  51 extern Mutex*   SymbolTable_lock;                // a lock on the symbol table
  52 extern Mutex*   StringTable_lock;                // a lock on the interned string table
  53 extern Monitor* StringDedupQueue_lock;           // a lock on the string deduplication queue
  54 extern Mutex*   StringDedupTable_lock;           // a lock on the string deduplication table
  55 extern Monitor* CodeCache_lock;                  // a lock on the CodeCache, rank is special, use MutexLockerEx
  56 extern Mutex*   MethodData_lock;                 // a lock on installation of method data
  57 extern Mutex*   TouchedMethodLog_lock;           // a lock on allocation of LogExecutedMethods info
  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* CGCPhaseManager_lock;            // a lock to protect a concurrent GC's phase management
  61 extern Monitor* VMOperationQueue_lock;           // a lock on queue of vm_operations waiting to execute
  62 extern Monitor* VMOperationRequest_lock;         // a lock on Threads waiting for a vm_operation to terminate
  63 extern Monitor* Safepoint_lock;                  // a lock used by the safepoint abstraction
  64 extern Monitor* Threads_lock;                    // a lock on the Threads table of active Java threads
  65                                                  // (also used by Safepoints too to block threads creation/destruction)
  66 extern Monitor* CGC_lock;                        // used for coordination between
  67                                                  // fore- & background GC threads.
  68 extern Monitor* STS_lock;                        // used for joining/leaving SuspendibleThreadSet.
  69 extern Monitor* FullGCCount_lock;                // in support of "concurrent" full gc
  70 extern Mutex*   SATB_Q_FL_lock;                  // Protects SATB Q
  71                                                  // buffer free list.
  72 extern Monitor* SATB_Q_CBL_mon;                  // Protects SATB Q
  73                                                  // completed buffer queue.
  74 extern Mutex*   Shared_SATB_Q_lock;              // Lock protecting SATB
  75                                                  // queue shared by
  76                                                  // non-Java threads.
  77 
  78 extern Mutex*   DirtyCardQ_FL_lock;              // Protects dirty card Q
  79                                                  // buffer free list.
  80 extern Monitor* DirtyCardQ_CBL_mon;              // Protects dirty card Q
  81                                                  // completed buffer queue.
  82 extern Mutex*   Shared_DirtyCardQ_lock;          // Lock protecting dirty card
  83                                                  // queue shared by
  84                                                  // non-Java threads.
  85 extern Mutex*   MarkStackFreeList_lock;          // Protects access to the global mark stack free list.
  86 extern Mutex*   MarkStackChunkList_lock;         // Protects access to the global mark stack chunk list.
  87 extern Mutex*   ParGCRareEvent_lock;             // Synchronizes various (rare) parallel GC ops.
  88 extern Mutex*   Compile_lock;                    // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
  89 extern Monitor* MethodCompileQueue_lock;         // a lock held when method compilations are enqueued, dequeued
  90 extern Monitor* CompileThread_lock;              // a lock held by compile threads during compilation system initialization
  91 extern Monitor* Compilation_lock;                // a lock used to pause compilation
  92 extern Mutex*   CompileTaskAlloc_lock;           // a lock held when CompileTasks are allocated
  93 extern Mutex*   CompileStatistics_lock;          // a lock held when updating compilation statistics
  94 extern Mutex*   DirectivesStack_lock;            // a lock held when mutating the dirstack and ref counting directives
  95 extern Mutex*   MultiArray_lock;                 // a lock used to guard allocation of multi-dim arrays
  96 extern Monitor* Terminator_lock;                 // a lock used to guard termination of the vm
  97 extern Monitor* BeforeExit_lock;                 // a lock used to guard cleanups and shutdown hooks
  98 extern Monitor* Notify_lock;                     // a lock used to synchronize the start-up of the vm
  99 extern Mutex*   ProfilePrint_lock;               // a lock used to serialize the printing of profiles
 100 extern Mutex*   ExceptionCache_lock;             // a lock used to synchronize exception cache updates
 101 extern Mutex*   OsrList_lock;                    // a lock used to serialize access to OSR queues
 102 
 103 #ifndef PRODUCT
 104 extern Mutex*   FullGCALot_lock;                 // a lock to make FullGCALot MT safe
 105 #endif // PRODUCT
 106 extern Mutex*   Debug1_lock;                     // A bunch of pre-allocated locks that can be used for tracing
 107 extern Mutex*   Debug2_lock;                     // down synchronization related bugs!
 108 extern Mutex*   Debug3_lock;
 109 
 110 extern Mutex*   RawMonitor_lock;
 111 extern Mutex*   PerfDataMemAlloc_lock;           // a lock on the allocator for PerfData memory for performance data
 112 extern Mutex*   PerfDataManager_lock;            // a long on access to PerfDataManager resources
 113 extern Mutex*   ParkerFreeList_lock;
 114 extern Mutex*   OopMapCacheAlloc_lock;           // protects allocation of oop_map caches
 115 
 116 extern Mutex*   FreeList_lock;                   // protects the free region list during safepoints
 117 extern Monitor* SecondaryFreeList_lock;          // protects the secondary free region list
 118 extern Mutex*   OldSets_lock;                    // protects the old region sets
 119 extern Monitor* RootRegionScan_lock;             // used to notify that the CM threads have finished scanning the IM snapshot regions
 120 
 121 extern Mutex*   Management_lock;                 // a lock used to serialize JVM management
 122 extern Monitor* Service_lock;                    // a lock used for service thread operation
 123 extern Monitor* PeriodicTask_lock;               // protects the periodic task structure
 124 extern Monitor* RedefineClasses_lock;            // locks classes from parallel redefinition
 125 
 126 #if INCLUDE_TRACE
 127 extern Mutex*   JfrStacktrace_lock;              // used to guard access to the JFR stacktrace table
 128 extern Monitor* JfrMsg_lock;                     // protects JFR messaging
 129 extern Mutex*   JfrBuffer_lock;                  // protects JFR buffer operations
 130 extern Mutex*   JfrStream_lock;                  // protects JFR stream access
 131 extern Mutex*   JfrThreadGroups_lock;            // protects JFR access to Thread Groups
 132 #endif
 133 
 134 #ifndef SUPPORTS_NATIVE_CX8
 135 extern Mutex*   UnsafeJlong_lock;                // provides Unsafe atomic updates to jlongs on platforms that don't support cx8
 136 #endif
 137 
 138 // A MutexLocker provides mutual exclusion with respect to a given mutex
 139 // for the scope which contains the locker.  The lock is an OS lock, not
 140 // an object lock, and the two do not interoperate.  Do not use Mutex-based
 141 // locks to lock on Java objects, because they will not be respected if a
 142 // that object is locked using the Java locking mechanism.
 143 //
 144 //                NOTE WELL!!
 145 //
 146 // See orderAccess.hpp.  We assume throughout the VM that MutexLocker's
 147 // and friends constructors do a fence, a lock and an acquire *in that
 148 // order*.  And that their destructors do a release and unlock, in *that*
 149 // order.  If their implementations change such that these assumptions
 150 // are violated, a whole lot of code will break.
 151 
 152 // Print all mutexes/monitors that are currently owned by a thread; called
 153 // by fatal error handler.
 154 void print_owned_locks_on_error(outputStream* st);
 155 
 156 char *lock_name(Mutex *mutex);
 157 
 158 class MutexLocker: StackObj {
 159  private:
 160   Monitor * _mutex;
 161  public:
 162   MutexLocker(Monitor * mutex) {
 163     assert(mutex->rank() != Mutex::special,
 164       "Special ranked mutex should only use MutexLockerEx");
 165     _mutex = mutex;
 166     _mutex->lock();
 167   }
 168 
 169   // Overloaded constructor passing current thread
 170   MutexLocker(Monitor * mutex, Thread *thread) {
 171     assert(mutex->rank() != Mutex::special,
 172       "Special ranked mutex should only use MutexLockerEx");
 173     _mutex = mutex;
 174     _mutex->lock(thread);
 175   }
 176 
 177   ~MutexLocker() {
 178     _mutex->unlock();
 179   }
 180 
 181 };
 182 
 183 // for debugging: check that we're already owning this lock (or are at a safepoint)
 184 #ifdef ASSERT
 185 void assert_locked_or_safepoint(const Monitor * lock);
 186 void assert_lock_strong(const Monitor * lock);
 187 #else
 188 #define assert_locked_or_safepoint(lock)
 189 #define assert_lock_strong(lock)
 190 #endif
 191 
 192 // A MutexLockerEx behaves like a MutexLocker when its constructor is
 193 // called with a Mutex.  Unlike a MutexLocker, its constructor can also be
 194 // called with NULL, in which case the MutexLockerEx is a no-op.  There
 195 // is also a corresponding MutexUnlockerEx.  We want to keep the
 196 // basic MutexLocker as fast as possible.  MutexLockerEx can also lock
 197 // without safepoint check.
 198 
 199 class MutexLockerEx: public StackObj {
 200  private:
 201   Monitor * _mutex;
 202  public:
 203   MutexLockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
 204     _mutex = mutex;
 205     if (_mutex != NULL) {
 206       assert(mutex->rank() > Mutex::special || no_safepoint_check,
 207         "Mutexes with rank special or lower should not do safepoint checks");
 208       if (no_safepoint_check)
 209         _mutex->lock_without_safepoint_check();
 210       else
 211         _mutex->lock();
 212     }
 213   }
 214 
 215   ~MutexLockerEx() {
 216     if (_mutex != NULL) {
 217       _mutex->unlock();
 218     }
 219   }
 220 };
 221 
 222 // A MonitorLockerEx is like a MutexLockerEx above, except it takes
 223 // a possibly null Monitor, and allows wait/notify as well which are
 224 // delegated to the underlying Monitor.
 225 
 226 class MonitorLockerEx: public MutexLockerEx {
 227  private:
 228   Monitor * _monitor;
 229  public:
 230   MonitorLockerEx(Monitor* monitor,
 231                   bool no_safepoint_check = !Mutex::_no_safepoint_check_flag):
 232     MutexLockerEx(monitor, no_safepoint_check),
 233     _monitor(monitor) {
 234     // Superclass constructor did locking
 235   }
 236 
 237   ~MonitorLockerEx() {
 238     #ifdef ASSERT
 239       if (_monitor != NULL) {
 240         assert_lock_strong(_monitor);
 241       }
 242     #endif  // ASSERT
 243     // Superclass destructor will do unlocking
 244   }
 245 
 246   bool wait(bool no_safepoint_check = !Mutex::_no_safepoint_check_flag,
 247             long timeout = 0,
 248             bool as_suspend_equivalent = !Mutex::_as_suspend_equivalent_flag) {
 249     if (_monitor != NULL) {
 250       return _monitor->wait(no_safepoint_check, timeout, as_suspend_equivalent);
 251     }
 252     return false;
 253   }
 254 
 255   bool notify_all() {
 256     if (_monitor != NULL) {
 257       return _monitor->notify_all();
 258     }
 259     return true;
 260   }
 261 
 262   bool notify() {
 263     if (_monitor != NULL) {
 264       return _monitor->notify();
 265     }
 266     return true;
 267   }
 268 };
 269 
 270 
 271 
 272 // A GCMutexLocker is usually initialized with a mutex that is
 273 // automatically acquired in order to do GC.  The function that
 274 // synchronizes using a GCMutexLocker may be called both during and between
 275 // GC's.  Thus, it must acquire the mutex if GC is not in progress, but not
 276 // if GC is in progress (since the mutex is already held on its behalf.)
 277 
 278 class GCMutexLocker: public StackObj {
 279 private:
 280   Monitor * _mutex;
 281   bool _locked;
 282 public:
 283   GCMutexLocker(Monitor * mutex);
 284   ~GCMutexLocker() { if (_locked) _mutex->unlock(); }
 285 };
 286 
 287 
 288 
 289 // A MutexUnlocker temporarily exits a previously
 290 // entered mutex for the scope which contains the unlocker.
 291 
 292 class MutexUnlocker: StackObj {
 293  private:
 294   Monitor * _mutex;
 295 
 296  public:
 297   MutexUnlocker(Monitor * mutex) {
 298     _mutex = mutex;
 299     _mutex->unlock();
 300   }
 301 
 302   ~MutexUnlocker() {
 303     _mutex->lock();
 304   }
 305 };
 306 
 307 // A MutexUnlockerEx temporarily exits a previously
 308 // entered mutex for the scope which contains the unlocker.
 309 
 310 class MutexUnlockerEx: StackObj {
 311  private:
 312   Monitor * _mutex;
 313   bool _no_safepoint_check;
 314 
 315  public:
 316   MutexUnlockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
 317     _mutex = mutex;
 318     _no_safepoint_check = no_safepoint_check;
 319     _mutex->unlock();
 320   }
 321 
 322   ~MutexUnlockerEx() {
 323     if (_no_safepoint_check == Mutex::_no_safepoint_check_flag) {
 324       _mutex->lock_without_safepoint_check();
 325     } else {
 326       _mutex->lock();
 327     }
 328   }
 329 };
 330 
 331 #ifndef PRODUCT
 332 //
 333 // A special MutexLocker that allows:
 334 //   - reentrant locking
 335 //   - locking out of order
 336 //
 337 // Only to be used for verify code, where we can relax out dead-lock
 338 // detection code a bit (unsafe, but probably ok). This code is NEVER to
 339 // be included in a product version.
 340 //
 341 class VerifyMutexLocker: StackObj {
 342  private:
 343   Monitor * _mutex;
 344   bool   _reentrant;
 345  public:
 346   VerifyMutexLocker(Monitor * mutex) {
 347     _mutex     = mutex;
 348     _reentrant = mutex->owned_by_self();
 349     if (!_reentrant) {
 350       // We temp. disable strict safepoint checking, while we require the lock
 351       FlagSetting fs(StrictSafepointChecks, false);
 352       _mutex->lock();
 353     }
 354   }
 355 
 356   ~VerifyMutexLocker() {
 357     if (!_reentrant) {
 358       _mutex->unlock();
 359     }
 360   }
 361 };
 362 
 363 #endif
 364 
 365 #endif // SHARE_VM_RUNTIME_MUTEXLOCKER_HPP