1 /*

     2  * Copyright 1997-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    24 

    25 // Mutexes used in the VM.

    26 

    27 extern Mutex*   Patching_lock;                   // a lock used to guard code patching of compiled code

    28 extern Monitor* SystemDictionary_lock;           // a lock on the system dictonary

    29 extern Mutex*   PackageTable_lock;               // a lock on the class loader package table

    30 extern Mutex*   CompiledIC_lock;                 // a lock used to guard compiled IC patching and access

    31 extern Mutex*   InlineCacheBuffer_lock;          // a lock used to guard the InlineCacheBuffer

    32 extern Mutex*   VMStatistic_lock;                // a lock used to guard statistics count increment

    33 extern Mutex*   JNIGlobalHandle_lock;            // a lock on creating JNI global handles

    34 extern Mutex*   JNIHandleBlockFreeList_lock;     // a lock on the JNI handle block free list

    35 extern Mutex*   JNICachedItableIndex_lock;       // a lock on caching an itable index during JNI invoke

    36 extern Mutex*   JmethodIdCreation_lock;          // a lock on creating JNI method identifiers

    37 extern Mutex*   JfieldIdCreation_lock;           // a lock on creating JNI static field identifiers

    38 extern Monitor* JNICritical_lock;                // a lock used while entering and exiting JNI critical regions, allows GC to sometimes get in

    39 extern Mutex*   JvmtiThreadState_lock;           // a lock on modification of JVMTI thread data

    40 extern Monitor* JvmtiPendingEvent_lock;          // a lock on the JVMTI pending events list

    41 extern Mutex*   Heap_lock;                       // a lock on the heap

    42 extern Mutex*   ExpandHeap_lock;                 // a lock on expanding the heap

    43 extern Mutex*   AdapterHandlerLibrary_lock;      // a lock on the AdapterHandlerLibrary

    44 extern Mutex*   SignatureHandlerLibrary_lock;    // a lock on the SignatureHandlerLibrary

    45 extern Mutex*   VtableStubs_lock;                // a lock on the VtableStubs

    46 extern Mutex*   SymbolTable_lock;                // a lock on the symbol table

    47 extern Mutex*   StringTable_lock;                // a lock on the interned string table

    48 extern Mutex*   CodeCache_lock;                  // a lock on the CodeCache, rank is special, use MutexLockerEx

    49 extern Mutex*   MethodData_lock;                 // a lock on installation of method data

    50 extern Mutex*   RetData_lock;                    // a lock on installation of RetData inside method data

    51 extern Mutex*   DerivedPointerTableGC_lock;      // a lock to protect the derived pointer table

    52 extern Monitor* VMOperationQueue_lock;           // a lock on queue of vm_operations waiting to execute

    53 extern Monitor* VMOperationRequest_lock;         // a lock on Threads waiting for a vm_operation to terminate

    54 extern Monitor* Safepoint_lock;                  // a lock used by the safepoint abstraction

    55 extern Monitor* SerializePage_lock;              // a lock used when VMThread changing serialize memory page permission during safepoint

    56 extern Monitor* Threads_lock;                    // a lock on the Threads table of active Java threads

    57                                                  // (also used by Safepoints too to block threads creation/destruction)

    58 extern Monitor* CGC_lock;                        // used for coordination between

    59                                                  // fore- & background GC threads.

    60 extern Mutex*   STS_init_lock;                   // coordinate initialization of SuspendibleThreadSets.

    61 extern Monitor* SLT_lock;                        // used in CMS GC for acquiring PLL

    62 extern Monitor* iCMS_lock;                       // CMS incremental mode start/stop notification

    63 extern Monitor* FullGCCount_lock;                // in support of "concurrent" full gc

    64                                                  // (see option ExplicitGCInvokesConcurrent)

    65 extern Mutex*   ParGCRareEvent_lock;             // Synchronizes various (rare) parallel GC ops.

    66 extern Mutex*   Compile_lock;                    // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)

    67 extern Monitor* MethodCompileQueue_lock;         // a lock held when method compilations are enqueued, dequeued

    68 #ifdef TIERED

    69 extern Monitor* C1_lock;                         // a lock to ensure on single c1 compile is ever active

    70 #endif // TIERED

    71 extern Monitor* CompileThread_lock;              // a lock held by compile threads during compilation system initialization

    72 extern Mutex*   CompileTaskAlloc_lock;           // a lock held when CompileTasks are allocated

    73 extern Mutex*   CompileStatistics_lock;          // a lock held when updating compilation statistics

    74 extern Mutex*   MultiArray_lock;                 // a lock used to guard allocation of multi-dim arrays

    75 extern Monitor* Terminator_lock;                 // a lock used to guard termination of the vm

    76 extern Monitor* BeforeExit_lock;                 // a lock used to guard cleanups and shutdown hooks

    77 extern Monitor* Notify_lock;                     // a lock used to synchronize the start-up of the vm

    78 extern Monitor* Interrupt_lock;                  // a lock used for condition variable mediated interrupt processing

    79 extern Monitor* ProfileVM_lock;                  // a lock used for profiling the VMThread

    80 extern Mutex*   ProfilePrint_lock;               // a lock used to serialize the printing of profiles

    81 extern Mutex*   ExceptionCache_lock;             // a lock used to synchronize exception cache updates

    82 extern Mutex*   OsrList_lock;                    // a lock used to serialize access to OSR queues

    83 

    84 #ifndef PRODUCT

    85 extern Mutex*   FullGCALot_lock;                 // a lock to make FullGCALot MT safe

    86 #endif

    87 extern Mutex*   Debug1_lock;                     // A bunch of pre-allocated locks that can be used for tracing

    88 extern Mutex*   Debug2_lock;                     // down synchronization related bugs!

    89 extern Mutex*   Debug3_lock;

    90 

    91 extern Mutex*   RawMonitor_lock;

    92 extern Mutex*   PerfDataMemAlloc_lock;           // a lock on the allocator for PerfData memory for performance data

    93 extern Mutex*   PerfDataManager_lock;            // a long on access to PerfDataManager resources

    94 extern Mutex*   ParkerFreeList_lock;

    95 extern Mutex*   OopMapCacheAlloc_lock;           // protects allocation of oop_map caches

    96 

    97 extern Mutex*   Management_lock;                 // a lock used to serialize JVM management

    98 extern Monitor* LowMemory_lock;                  // a lock used for low memory detection

    99 

   100 // A MutexLocker provides mutual exclusion with respect to a given mutex

   101 // for the scope which contains the locker.  The lock is an OS lock, not

   102 // an object lock, and the two do not interoperate.  Do not use Mutex-based

   103 // locks to lock on Java objects, because they will not be respected if a

   104 // that object is locked using the Java locking mechanism.

   105 //

   106 //                NOTE WELL!!

   107 //

   108 // See orderAccess.hpp.  We assume throughout the VM that MutexLocker's

   109 // and friends constructors do a fence, a lock and an acquire *in that

   110 // order*.  And that their destructors do a release and unlock, in *that*

   111 // order.  If their implementations change such that these assumptions

   112 // are violated, a whole lot of code will break.

   113 

   114 // Print all mutexes/monitors that are currently owned by a thread; called

   115 // by fatal error handler.

   116 void print_owned_locks_on_error(outputStream* st);

   117 

   118 char *lock_name(Mutex *mutex);

   119 

   120 class MutexLocker: StackObj {

   121  private:

   122   Monitor * _mutex;

   123  public:

   124   MutexLocker(Monitor * mutex) {

   125     assert(mutex->rank() != Mutex::special,

   126       "Special ranked mutex should only use MutexLockerEx");

   127     _mutex = mutex;

   128     _mutex->lock();

   129   }

   130 

   131   // Overloaded constructor passing current thread

   132   MutexLocker(Monitor * mutex, Thread *thread) {

   133     assert(mutex->rank() != Mutex::special,

   134       "Special ranked mutex should only use MutexLockerEx");

   135     _mutex = mutex;

   136     _mutex->lock(thread);

   137   }

   138 

   139   ~MutexLocker() {

   140     _mutex->unlock();

   141   }

   142 

   143 };

   144 

   145 // for debugging: check that we're already owning this lock (or are at a safepoint)

   146 #ifdef ASSERT

   147 void assert_locked_or_safepoint(const Monitor * lock);

   148 void assert_lock_strong(const Monitor * lock);

   149 #else

   150 #define assert_locked_or_safepoint(lock)

   151 #define assert_lock_strong(lock)

   152 #endif

   153 

   154 // A MutexLockerEx behaves like a MutexLocker when its constructor is

   155 // called with a Mutex.  Unlike a MutexLocker, its constructor can also be

   156 // called with NULL, in which case the MutexLockerEx is a no-op.  There

   157 // is also a corresponding MutexUnlockerEx.  We want to keep the

   158 // basic MutexLocker as fast as possible.  MutexLockerEx can also lock

   159 // without safepoint check.

   160 

   161 class MutexLockerEx: public StackObj {

   162  private:

   163   Monitor * _mutex;

   164  public:

   165   MutexLockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {

   166     _mutex = mutex;

   167     if (_mutex != NULL) {

   168       assert(mutex->rank() > Mutex::special || no_safepoint_check,

   169         "Mutexes with rank special or lower should not do safepoint checks");

   170       if (no_safepoint_check)

   171         _mutex->lock_without_safepoint_check();

   172       else

   173         _mutex->lock();

   174     }

   175   }

   176 

   177   ~MutexLockerEx() {

   178     if (_mutex != NULL) {

   179       _mutex->unlock();

   180     }

   181   }

   182 };

   183 

   184 // A MonitorLockerEx is like a MutexLockerEx above, except it takes

   185 // a possibly null Monitor, and allows wait/notify as well which are

   186 // delegated to the underlying Monitor.

   187 

   188 class MonitorLockerEx: public MutexLockerEx {

   189  private:

   190   Monitor * _monitor;

   191  public:

   192   MonitorLockerEx(Monitor* monitor,

   193                   bool no_safepoint_check = !Mutex::_no_safepoint_check_flag):

   194     MutexLockerEx(monitor, no_safepoint_check),

   195     _monitor(monitor) {

   196     // Superclass constructor did locking

   197   }

   198 

   199   ~MonitorLockerEx() {

   200     #ifdef ASSERT

   201       if (_monitor != NULL) {

   202         assert_lock_strong(_monitor);

   203       }

   204     #endif  // ASSERT

   205     // Superclass destructor will do unlocking

   206   }

   207 

   208   bool wait(bool no_safepoint_check = !Mutex::_no_safepoint_check_flag,

   209             long timeout = 0,

   210             bool as_suspend_equivalent = !Mutex::_as_suspend_equivalent_flag) {

   211     if (_monitor != NULL) {

   212       return _monitor->wait(no_safepoint_check, timeout, as_suspend_equivalent);

   213     }

   214     return false;

   215   }

   216 

   217   bool notify_all() {

   218     if (_monitor != NULL) {

   219       return _monitor->notify_all();

   220     }

   221     return true;

   222   }

   223 

   224   bool notify() {

   225     if (_monitor != NULL) {

   226       return _monitor->notify();

   227     }

   228     return true;

   229   }

   230 };

   231 

   232 

   233 

   234 // A GCMutexLocker is usually initialized with a mutex that is

   235 // automatically acquired in order to do GC.  The function that

   236 // synchronizes using a GCMutexLocker may be called both during and between

   237 // GC's.  Thus, it must acquire the mutex if GC is not in progress, but not

   238 // if GC is in progress (since the mutex is already held on its behalf.)

   239 

   240 class GCMutexLocker: public StackObj {

   241 private:

   242   Monitor * _mutex;

   243   bool _locked;

   244 public:

   245   GCMutexLocker(Monitor * mutex);

   246   ~GCMutexLocker() { if (_locked) _mutex->unlock(); }

   247 };

   248 

   249 

   250 

   251 // A MutexUnlocker temporarily exits a previously

   252 // entered mutex for the scope which contains the unlocker.

   253 

   254 class MutexUnlocker: StackObj {

   255  private:

   256   Monitor * _mutex;

   257 

   258  public:

   259   MutexUnlocker(Monitor * mutex) {

   260     _mutex = mutex;

   261     _mutex->unlock();

   262   }

   263 

   264   ~MutexUnlocker() {

   265     _mutex->lock();

   266   }

   267 };

   268 

   269 // A MutexUnlockerEx temporarily exits a previously

   270 // entered mutex for the scope which contains the unlocker.

   271 

   272 class MutexUnlockerEx: StackObj {

   273  private:

   274   Monitor * _mutex;

   275   bool _no_safepoint_check;

   276 

   277  public:

   278   MutexUnlockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {

   279     _mutex = mutex;

   280     _no_safepoint_check = no_safepoint_check;

   281     _mutex->unlock();

   282   }

   283 

   284   ~MutexUnlockerEx() {

   285     if (_no_safepoint_check == Mutex::_no_safepoint_check_flag) {

   286       _mutex->lock_without_safepoint_check();

   287     } else {

   288       _mutex->lock();

   289     }

   290   }

   291 };

   292 

   293 #ifndef PRODUCT

   294 //

   295 // A special MutexLocker that allows:

   296 //   - reentrant locking

   297 //   - locking out of order

   298 //

   299 // Only too be used for verify code, where we can relaxe out dead-lock

   300 // dection code a bit (unsafe, but probably ok). This code is NEVER to

   301 // be included in a product version.

   302 //

   303 class VerifyMutexLocker: StackObj {

   304  private:

   305   Monitor * _mutex;

   306   bool   _reentrant;

   307  public:

   308   VerifyMutexLocker(Monitor * mutex) {

   309     _mutex     = mutex;

   310     _reentrant = mutex->owned_by_self();

   311     if (!_reentrant) {

   312       // We temp. diable strict safepoint checking, while we require the lock

   313       FlagSetting fs(StrictSafepointChecks, false);

   314       _mutex->lock();

   315     }

   316   }

   317 

   318   ~VerifyMutexLocker() {

   319     if (!_reentrant) {

   320       _mutex->unlock();

   321     }

   322   }

   323 };

   324 

   325 #endif