1 /*
   2  * Copyright (c) 1997, 2018, 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
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  22  *
  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/flags/flagSetting.hpp"
  30 #include "runtime/mutex.hpp"
  31 
  32 // Mutexes used in the VM.
  33 
  34 extern Mutex*   Patching_lock;                   // a lock used to guard code patching of compiled code
  35 extern Monitor* SystemDictionary_lock;           // a lock on the system dictionary
  36 extern Mutex*   SharedDictionary_lock;           // a lock on the CDS shared dictionary
  37 extern Mutex*   Module_lock;                     // a lock on module and package related data structures
  38 extern Mutex*   CompiledIC_lock;                 // a lock used to guard compiled IC patching and access
  39 extern Mutex*   InlineCacheBuffer_lock;          // a lock used to guard the InlineCacheBuffer
  40 extern Mutex*   VMStatistic_lock;                // a lock used to guard statistics count increment
  41 extern Mutex*   JNIGlobalAlloc_lock;             // JNI global storage allocate list lock
  42 extern Mutex*   JNIGlobalActive_lock;            // JNI global storage active list lock
  43 extern Mutex*   JNIWeakAlloc_lock;               // JNI weak storage allocate list lock
  44 extern Mutex*   JNIWeakActive_lock;              // JNI weak storage active list lock
  45 extern Mutex*   JNIHandleBlockFreeList_lock;     // a lock on the JNI handle block free list
  46 extern Mutex*   VMWeakAlloc_lock;                // VM Weak Handles storage allocate list lock
  47 extern Mutex*   VMWeakActive_lock;               // VM Weak Handles storage active list lock
  48 extern Mutex*   ResolvedMethodTable_lock;        // a lock on the ResolvedMethodTable updates
  49 extern Mutex*   JmethodIdCreation_lock;          // a lock on creating JNI method identifiers
  50 extern Mutex*   JfieldIdCreation_lock;           // a lock on creating JNI static field identifiers
  51 extern Monitor* JNICritical_lock;                // a lock used while entering and exiting JNI critical regions, allows GC to sometimes get in
  52 extern Mutex*   JvmtiThreadState_lock;           // a lock on modification of JVMTI thread data
  53 extern Monitor* Heap_lock;                       // a lock on the heap
  54 extern Mutex*   ExpandHeap_lock;                 // a lock on expanding the heap
  55 extern Mutex*   AdapterHandlerLibrary_lock;      // a lock on the AdapterHandlerLibrary
  56 extern Mutex*   SignatureHandlerLibrary_lock;    // a lock on the SignatureHandlerLibrary
  57 extern Mutex*   VtableStubs_lock;                // a lock on the VtableStubs
  58 extern Mutex*   SymbolTable_lock;                // a lock on the symbol table
  59 extern Mutex*   StringTable_lock;                // a lock on the interned string table
  60 extern Monitor* StringDedupQueue_lock;           // a lock on the string deduplication queue
  61 extern Mutex*   StringDedupTable_lock;           // a lock on the string deduplication table
  62 extern Monitor* CodeCache_lock;                  // a lock on the CodeCache, rank is special, use MutexLockerEx
  63 extern Mutex*   MethodData_lock;                 // a lock on installation of method data
  64 extern Mutex*   TouchedMethodLog_lock;           // a lock on allocation of LogExecutedMethods info
  65 extern Mutex*   RetData_lock;                    // a lock on installation of RetData inside method data
  66 extern Mutex*   DerivedPointerTableGC_lock;      // a lock to protect the derived pointer table
  67 extern Monitor* CGCPhaseManager_lock;            // a lock to protect a concurrent GC's phase management
  68 extern Monitor* VMOperationQueue_lock;           // a lock on queue of vm_operations waiting to execute
  69 extern Monitor* VMOperationRequest_lock;         // a lock on Threads waiting for a vm_operation to terminate
  70 extern Monitor* Safepoint_lock;                  // a lock used by the safepoint abstraction
  71 extern Monitor* Threads_lock;                    // a lock on the Threads table of active Java threads
  72                                                  // (also used by Safepoints too to block threads creation/destruction)
  73 extern Monitor* CGC_lock;                        // used for coordination between
  74                                                  // fore- & background GC threads.
  75 extern Monitor* STS_lock;                        // used for joining/leaving SuspendibleThreadSet.
  76 extern Monitor* FullGCCount_lock;                // in support of "concurrent" full gc
  77 extern Mutex*   SATB_Q_FL_lock;                  // Protects SATB Q
  78                                                  // buffer free list.
  79 extern Monitor* SATB_Q_CBL_mon;                  // Protects SATB Q
  80                                                  // completed buffer queue.
  81 extern Mutex*   Shared_SATB_Q_lock;              // Lock protecting SATB
  82                                                  // queue shared by
  83                                                  // non-Java threads.
  84 
  85 extern Mutex*   DirtyCardQ_FL_lock;              // Protects dirty card Q
  86                                                  // buffer free list.
  87 extern Monitor* DirtyCardQ_CBL_mon;              // Protects dirty card Q
  88                                                  // completed buffer queue.
  89 extern Mutex*   Shared_DirtyCardQ_lock;          // Lock protecting dirty card
  90                                                  // queue shared by
  91                                                  // non-Java threads.
  92 extern Mutex*   MarkStackFreeList_lock;          // Protects access to the global mark stack free list.
  93 extern Mutex*   MarkStackChunkList_lock;         // Protects access to the global mark stack chunk list.
  94 extern Mutex*   ParGCRareEvent_lock;             // Synchronizes various (rare) parallel GC ops.
  95 extern Mutex*   Compile_lock;                    // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
  96 extern Monitor* MethodCompileQueue_lock;         // a lock held when method compilations are enqueued, dequeued
  97 extern Monitor* CompileThread_lock;              // a lock held by compile threads during compilation system initialization
  98 extern Monitor* Compilation_lock;                // a lock used to pause compilation
  99 extern Mutex*   CompileTaskAlloc_lock;           // a lock held when CompileTasks are allocated
 100 extern Mutex*   CompileStatistics_lock;          // a lock held when updating compilation statistics
 101 extern Mutex*   DirectivesStack_lock;            // a lock held when mutating the dirstack and ref counting directives
 102 extern Mutex*   MultiArray_lock;                 // a lock used to guard allocation of multi-dim arrays
 103 extern Monitor* Terminator_lock;                 // a lock used to guard termination of the vm
 104 extern Monitor* BeforeExit_lock;                 // a lock used to guard cleanups and shutdown hooks
 105 extern Monitor* Notify_lock;                     // a lock used to synchronize the start-up of the vm
 106 extern Mutex*   ProfilePrint_lock;               // a lock used to serialize the printing of profiles
 107 extern Mutex*   ExceptionCache_lock;             // a lock used to synchronize exception cache updates
 108 extern Mutex*   OsrList_lock;                    // a lock used to serialize access to OSR queues
 109 
 110 #ifndef PRODUCT
 111 extern Mutex*   FullGCALot_lock;                 // a lock to make FullGCALot MT safe
 112 #endif // PRODUCT
 113 extern Mutex*   Debug1_lock;                     // A bunch of pre-allocated locks that can be used for tracing
 114 extern Mutex*   Debug2_lock;                     // down synchronization related bugs!
 115 extern Mutex*   Debug3_lock;
 116 
 117 extern Mutex*   RawMonitor_lock;
 118 extern Mutex*   PerfDataMemAlloc_lock;           // a lock on the allocator for PerfData memory for performance data
 119 extern Mutex*   PerfDataManager_lock;            // a long on access to PerfDataManager resources
 120 extern Mutex*   ParkerFreeList_lock;
 121 extern Mutex*   OopMapCacheAlloc_lock;           // protects allocation of oop_map caches
 122 
 123 extern Mutex*   FreeList_lock;                   // protects the free region list during safepoints
 124 extern Mutex*   OldSets_lock;                    // protects the old region sets
 125 extern Monitor* RootRegionScan_lock;             // used to notify that the CM threads have finished scanning the IM snapshot regions
 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 extern Monitor* RedefineClasses_lock;            // locks classes from parallel redefinition
 131 extern Mutex*   ThreadHeapSampler_lock;          // protects the static data for initialization.
 132 
 133 #if INCLUDE_JFR
 134 extern Mutex*   JfrStacktrace_lock;              // used to guard access to the JFR stacktrace table
 135 extern Monitor* JfrMsg_lock;                     // protects JFR messaging
 136 extern Mutex*   JfrBuffer_lock;                  // protects JFR buffer operations
 137 extern Mutex*   JfrStream_lock;                  // protects JFR stream access
 138 #endif
 139 
 140 #ifndef SUPPORTS_NATIVE_CX8
 141 extern Mutex*   UnsafeJlong_lock;                // provides Unsafe atomic updates to jlongs on platforms that don't support cx8
 142 #endif
 143 
 144 extern Mutex*   MetaspaceExpand_lock;            // protects Metaspace virtualspace and chunk expansions
 145 
 146 
 147 extern Monitor* CodeHeapStateAnalytics_lock;     // lock print functions against concurrent analyze functions.
 148                                                  // Only used locally in PrintCodeCacheLayout processing.
 149 
 150 // A MutexLocker provides mutual exclusion with respect to a given mutex
 151 // for the scope which contains the locker.  The lock is an OS lock, not
 152 // an object lock, and the two do not interoperate.  Do not use Mutex-based
 153 // locks to lock on Java objects, because they will not be respected if a
 154 // that object is locked using the Java locking mechanism.
 155 //
 156 //                NOTE WELL!!
 157 //
 158 // See orderAccess.hpp.  We assume throughout the VM that MutexLocker's
 159 // and friends constructors do a fence, a lock and an acquire *in that
 160 // order*.  And that their destructors do a release and unlock, in *that*
 161 // order.  If their implementations change such that these assumptions
 162 // are violated, a whole lot of code will break.
 163 
 164 // Print all mutexes/monitors that are currently owned by a thread; called
 165 // by fatal error handler.
 166 void print_owned_locks_on_error(outputStream* st);
 167 
 168 char *lock_name(Mutex *mutex);
 169 
 170 class MutexLocker: StackObj {
 171  private:
 172   Monitor * _mutex;
 173  public:
 174   MutexLocker(Monitor * mutex) {
 175     assert(mutex->rank() != Mutex::special,
 176       "Special ranked mutex should only use MutexLockerEx");
 177     _mutex = mutex;
 178     _mutex->lock();
 179   }
 180 
 181   // Overloaded constructor passing current thread
 182   MutexLocker(Monitor * mutex, Thread *thread) {
 183     assert(mutex->rank() != Mutex::special,
 184       "Special ranked mutex should only use MutexLockerEx");
 185     _mutex = mutex;
 186     _mutex->lock(thread);
 187   }
 188 
 189   ~MutexLocker() {
 190     _mutex->unlock();
 191   }
 192 
 193 };
 194 
 195 // for debugging: check that we're already owning this lock (or are at a safepoint)
 196 #ifdef ASSERT
 197 void assert_locked_or_safepoint(const Monitor * lock);
 198 void assert_lock_strong(const Monitor * lock);
 199 #else
 200 #define assert_locked_or_safepoint(lock)
 201 #define assert_lock_strong(lock)
 202 #endif
 203 
 204 // A MutexLockerEx behaves like a MutexLocker when its constructor is
 205 // called with a Mutex.  Unlike a MutexLocker, its constructor can also be
 206 // called with NULL, in which case the MutexLockerEx is a no-op.  There
 207 // is also a corresponding MutexUnlockerEx.  We want to keep the
 208 // basic MutexLocker as fast as possible.  MutexLockerEx can also lock
 209 // without safepoint check.
 210 
 211 class MutexLockerEx: public StackObj {
 212  private:
 213   Monitor * _mutex;
 214  public:
 215   MutexLockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
 216     _mutex = mutex;
 217     if (_mutex != NULL) {
 218       assert(mutex->rank() > Mutex::special || no_safepoint_check,
 219         "Mutexes with rank special or lower should not do safepoint checks");
 220       if (no_safepoint_check)
 221         _mutex->lock_without_safepoint_check();
 222       else
 223         _mutex->lock();
 224     }
 225   }
 226 
 227   ~MutexLockerEx() {
 228     if (_mutex != NULL) {
 229       _mutex->unlock();
 230     }
 231   }
 232 };
 233 
 234 // A MonitorLockerEx is like a MutexLockerEx above, except it takes
 235 // a possibly null Monitor, and allows wait/notify as well which are
 236 // delegated to the underlying Monitor.
 237 
 238 class MonitorLockerEx: public MutexLockerEx {
 239  private:
 240   Monitor * _monitor;
 241  public:
 242   MonitorLockerEx(Monitor* monitor,
 243                   bool no_safepoint_check = !Mutex::_no_safepoint_check_flag):
 244     MutexLockerEx(monitor, no_safepoint_check),
 245     _monitor(monitor) {
 246     // Superclass constructor did locking
 247   }
 248 
 249   ~MonitorLockerEx() {
 250     #ifdef ASSERT
 251       if (_monitor != NULL) {
 252         assert_lock_strong(_monitor);
 253       }
 254     #endif  // ASSERT
 255     // Superclass destructor will do unlocking
 256   }
 257 
 258   bool wait(bool no_safepoint_check = !Mutex::_no_safepoint_check_flag,
 259             long timeout = 0,
 260             bool as_suspend_equivalent = !Mutex::_as_suspend_equivalent_flag) {
 261     if (_monitor != NULL) {
 262       return _monitor->wait(no_safepoint_check, timeout, as_suspend_equivalent);
 263     }
 264     return false;
 265   }
 266 
 267   bool notify_all() {
 268     if (_monitor != NULL) {
 269       return _monitor->notify_all();
 270     }
 271     return true;
 272   }
 273 
 274   bool notify() {
 275     if (_monitor != NULL) {
 276       return _monitor->notify();
 277     }
 278     return true;
 279   }
 280 };
 281 
 282 
 283 
 284 // A GCMutexLocker is usually initialized with a mutex that is
 285 // automatically acquired in order to do GC.  The function that
 286 // synchronizes using a GCMutexLocker may be called both during and between
 287 // GC's.  Thus, it must acquire the mutex if GC is not in progress, but not
 288 // if GC is in progress (since the mutex is already held on its behalf.)
 289 
 290 class GCMutexLocker: public StackObj {
 291 private:
 292   Monitor * _mutex;
 293   bool _locked;
 294 public:
 295   GCMutexLocker(Monitor * mutex);
 296   ~GCMutexLocker() { if (_locked) _mutex->unlock(); }
 297 };
 298 
 299 
 300 
 301 // A MutexUnlocker temporarily exits a previously
 302 // entered mutex for the scope which contains the unlocker.
 303 
 304 class MutexUnlocker: StackObj {
 305  private:
 306   Monitor * _mutex;
 307 
 308  public:
 309   MutexUnlocker(Monitor * mutex) {
 310     _mutex = mutex;
 311     _mutex->unlock();
 312   }
 313 
 314   ~MutexUnlocker() {
 315     _mutex->lock();
 316   }
 317 };
 318 
 319 // A MutexUnlockerEx temporarily exits a previously
 320 // entered mutex for the scope which contains the unlocker.
 321 
 322 class MutexUnlockerEx: StackObj {
 323  private:
 324   Monitor * _mutex;
 325   bool _no_safepoint_check;
 326 
 327  public:
 328   MutexUnlockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
 329     _mutex = mutex;
 330     _no_safepoint_check = no_safepoint_check;
 331     _mutex->unlock();
 332   }
 333 
 334   ~MutexUnlockerEx() {
 335     if (_no_safepoint_check == Mutex::_no_safepoint_check_flag) {
 336       _mutex->lock_without_safepoint_check();
 337     } else {
 338       _mutex->lock();
 339     }
 340   }
 341 };
 342 
 343 #ifndef PRODUCT
 344 //
 345 // A special MutexLocker that allows:
 346 //   - reentrant locking
 347 //   - locking out of order
 348 //
 349 // Only to be used for verify code, where we can relax out dead-lock
 350 // detection code a bit (unsafe, but probably ok). This code is NEVER to
 351 // be included in a product version.
 352 //
 353 class VerifyMutexLocker: StackObj {
 354  private:
 355   Monitor * _mutex;
 356   bool   _reentrant;
 357  public:
 358   VerifyMutexLocker(Monitor * mutex) {
 359     _mutex     = mutex;
 360     _reentrant = mutex->owned_by_self();
 361     if (!_reentrant) {
 362       // We temp. disable strict safepoint checking, while we require the lock
 363       FlagSetting fs(StrictSafepointChecks, false);
 364       _mutex->lock();
 365     }
 366   }
 367 
 368   ~VerifyMutexLocker() {
 369     if (!_reentrant) {
 370       _mutex->unlock();
 371     }
 372   }
 373 };
 374 
 375 #endif
 376 
 377 #endif // SHARE_VM_RUNTIME_MUTEXLOCKER_HPP