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
  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 #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*   JNIGlobalAlloc_lock;             // JNI global storage allocate list lock
  40 extern Mutex*   JNIGlobalActive_lock;            // JNI global storage active list lock
  41 extern Mutex*   JNIWeakAlloc_lock;               // JNI weak storage allocate list lock
  42 extern Mutex*   JNIWeakActive_lock;              // JNI weak storage active list lock
  43 extern Mutex*   JNIHandleBlockFreeList_lock;     // a lock on the JNI handle block free list
  44 extern Mutex*   ResolvedMethodTable_lock;        // a lock on the ResolvedMethodTable updates
  45 extern Mutex*   JmethodIdCreation_lock;          // a lock on creating JNI method identifiers
  46 extern Mutex*   JfieldIdCreation_lock;           // a lock on creating JNI static field identifiers
  47 extern Monitor* JNICritical_lock;                // a lock used while entering and exiting JNI critical regions, allows GC to sometimes get in
  48 extern Mutex*   JvmtiThreadState_lock;           // a lock on modification of JVMTI thread data
  49 extern Monitor* Heap_lock;                       // a lock on the heap
  50 extern Mutex*   ExpandHeap_lock;                 // a lock on expanding the heap
  51 extern Mutex*   AdapterHandlerLibrary_lock;      // a lock on the AdapterHandlerLibrary
  52 extern Mutex*   SignatureHandlerLibrary_lock;    // a lock on the SignatureHandlerLibrary
  53 extern Mutex*   VtableStubs_lock;                // a lock on the VtableStubs
  54 extern Mutex*   SymbolTable_lock;                // a lock on the symbol table
  55 extern Mutex*   StringTable_lock;                // a lock on the interned string table
  56 extern Monitor* StringDedupQueue_lock;           // a lock on the string deduplication queue
  57 extern Mutex*   StringDedupTable_lock;           // a lock on the string deduplication table
  58 extern Monitor* CodeCache_lock;                  // a lock on the CodeCache, rank is special, use MutexLockerEx
  59 extern Mutex*   MethodData_lock;                 // a lock on installation of method data
  60 extern Mutex*   TouchedMethodLog_lock;           // a lock on allocation of LogExecutedMethods info
  61 extern Mutex*   RetData_lock;                    // a lock on installation of RetData inside method data
  62 extern Mutex*   DerivedPointerTableGC_lock;      // a lock to protect the derived pointer table
  63 extern Monitor* CGCPhaseManager_lock;            // a lock to protect a concurrent GC's phase management
  64 extern Monitor* VMOperationQueue_lock;           // a lock on queue of vm_operations waiting to execute
  65 extern Monitor* VMOperationRequest_lock;         // a lock on Threads waiting for a vm_operation to terminate
  66 extern Monitor* Safepoint_lock;                  // a lock used by the safepoint abstraction
  67 extern Monitor* Threads_lock;                    // a lock on the Threads table of active Java threads
  68                                                  // (also used by Safepoints too to block threads creation/destruction)
  69 extern Monitor* CGC_lock;                        // used for coordination between
  70                                                  // fore- & background GC threads.
  71 extern Monitor* STS_lock;                        // used for joining/leaving SuspendibleThreadSet.
  72 extern Monitor* FullGCCount_lock;                // in support of "concurrent" full gc
  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 extern Mutex*   MarkStackFreeList_lock;          // Protects access to the global mark stack free list.
  89 extern Mutex*   MarkStackChunkList_lock;         // Protects access to the global mark stack chunk list.
  90 extern Mutex*   ParGCRareEvent_lock;             // Synchronizes various (rare) parallel GC ops.
  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 Monitor* Compilation_lock;                // a lock used to pause compilation
  95 extern Mutex*   CompileTaskAlloc_lock;           // a lock held when CompileTasks are allocated
  96 extern Mutex*   CompileStatistics_lock;          // a lock held when updating compilation statistics
  97 extern Mutex*   DirectivesStack_lock;            // a lock held when mutating the dirstack and ref counting directives
  98 extern Mutex*   MultiArray_lock;                 // a lock used to guard allocation of multi-dim arrays
  99 extern Monitor* Terminator_lock;                 // a lock used to guard termination of the vm
 100 extern Monitor* BeforeExit_lock;                 // a lock used to guard cleanups and shutdown hooks
 101 extern Monitor* Notify_lock;                     // a lock used to synchronize the start-up of the vm
 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 
 124 extern Mutex*   Management_lock;                 // a lock used to serialize JVM management
 125 extern Monitor* Service_lock;                    // a lock used for service thread operation
 126 extern Monitor* PeriodicTask_lock;               // protects the periodic task structure
 127 extern Monitor* RedefineClasses_lock;            // locks classes from parallel redefinition
 128 
 129 #if INCLUDE_TRACE
 130 extern Mutex*   JfrStacktrace_lock;              // used to guard access to the JFR stacktrace table
 131 extern Monitor* JfrMsg_lock;                     // protects JFR messaging
 132 extern Mutex*   JfrBuffer_lock;                  // protects JFR buffer operations
 133 extern Mutex*   JfrStream_lock;                  // protects JFR stream access
 134 #endif
 135 
 136 #ifndef SUPPORTS_NATIVE_CX8
 137 extern Mutex*   UnsafeJlong_lock;                // provides Unsafe atomic updates to jlongs on platforms that don't support cx8
 138 #endif
 139 
 140 extern Monitor* CodeHeapStateAnalytics_lock;     // lock print functions against concurrent analyze functions.
 141                                                  // Only used locally in PrintCodeCacheLayout processing.
 142 
 143 // A MutexLocker provides mutual exclusion with respect to a given mutex
 144 // for the scope which contains the locker.  The lock is an OS lock, not
 145 // an object lock, and the two do not interoperate.  Do not use Mutex-based
 146 // locks to lock on Java objects, because they will not be respected if a
 147 // that object is locked using the Java locking mechanism.
 148 //
 149 //                NOTE WELL!!
 150 //
 151 // See orderAccess.hpp.  We assume throughout the VM that MutexLocker's
 152 // and friends constructors do a fence, a lock and an acquire *in that
 153 // order*.  And that their destructors do a release and unlock, in *that*
 154 // order.  If their implementations change such that these assumptions
 155 // are violated, a whole lot of code will break.
 156 
 157 // Print all mutexes/monitors that are currently owned by a thread; called
 158 // by fatal error handler.
 159 void print_owned_locks_on_error(outputStream* st);
 160 
 161 char *lock_name(Mutex *mutex);
 162 
 163 class MutexLocker: StackObj {
 164  private:
 165   Monitor * _mutex;
 166  public:
 167   MutexLocker(Monitor * mutex) {
 168     assert(mutex->rank() != Mutex::special,
 169       "Special ranked mutex should only use MutexLockerEx");
 170     _mutex = mutex;
 171     _mutex->lock();
 172   }
 173 
 174   // Overloaded constructor passing current thread
 175   MutexLocker(Monitor * mutex, Thread *thread) {
 176     assert(mutex->rank() != Mutex::special,
 177       "Special ranked mutex should only use MutexLockerEx");
 178     _mutex = mutex;
 179     _mutex->lock(thread);
 180   }
 181 
 182   ~MutexLocker() {
 183     _mutex->unlock();
 184   }
 185 
 186 };
 187 
 188 // for debugging: check that we're already owning this lock (or are at a safepoint)
 189 #ifdef ASSERT
 190 void assert_locked_or_safepoint(const Monitor * lock);
 191 void assert_lock_strong(const Monitor * lock);
 192 #else
 193 #define assert_locked_or_safepoint(lock)
 194 #define assert_lock_strong(lock)
 195 #endif
 196 
 197 // A MutexLockerEx behaves like a MutexLocker when its constructor is
 198 // called with a Mutex.  Unlike a MutexLocker, its constructor can also be
 199 // called with NULL, in which case the MutexLockerEx is a no-op.  There
 200 // is also a corresponding MutexUnlockerEx.  We want to keep the
 201 // basic MutexLocker as fast as possible.  MutexLockerEx can also lock
 202 // without safepoint check.
 203 
 204 class MutexLockerEx: public StackObj {
 205  private:
 206   Monitor * _mutex;
 207  public:
 208   MutexLockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
 209     _mutex = mutex;
 210     if (_mutex != NULL) {
 211       assert(mutex->rank() > Mutex::special || no_safepoint_check,
 212         "Mutexes with rank special or lower should not do safepoint checks");
 213       if (no_safepoint_check)
 214         _mutex->lock_without_safepoint_check();
 215       else
 216         _mutex->lock();
 217     }
 218   }
 219 
 220   ~MutexLockerEx() {
 221     if (_mutex != NULL) {
 222       _mutex->unlock();
 223     }
 224   }
 225 };
 226 
 227 // A MonitorLockerEx is like a MutexLockerEx above, except it takes
 228 // a possibly null Monitor, and allows wait/notify as well which are
 229 // delegated to the underlying Monitor.
 230 
 231 class MonitorLockerEx: public MutexLockerEx {
 232  private:
 233   Monitor * _monitor;
 234  public:
 235   MonitorLockerEx(Monitor* monitor,
 236                   bool no_safepoint_check = !Mutex::_no_safepoint_check_flag):
 237     MutexLockerEx(monitor, no_safepoint_check),
 238     _monitor(monitor) {
 239     // Superclass constructor did locking
 240   }
 241 
 242   ~MonitorLockerEx() {
 243     #ifdef ASSERT
 244       if (_monitor != NULL) {
 245         assert_lock_strong(_monitor);
 246       }
 247     #endif  // ASSERT
 248     // Superclass destructor will do unlocking
 249   }
 250 
 251   bool wait(bool no_safepoint_check = !Mutex::_no_safepoint_check_flag,
 252             long timeout = 0,
 253             bool as_suspend_equivalent = !Mutex::_as_suspend_equivalent_flag) {
 254     if (_monitor != NULL) {
 255       return _monitor->wait(no_safepoint_check, timeout, as_suspend_equivalent);
 256     }
 257     return false;
 258   }
 259 
 260   bool notify_all() {
 261     if (_monitor != NULL) {
 262       return _monitor->notify_all();
 263     }
 264     return true;
 265   }
 266 
 267   bool notify() {
 268     if (_monitor != NULL) {
 269       return _monitor->notify();
 270     }
 271     return true;
 272   }
 273 };
 274 
 275 
 276 
 277 // A GCMutexLocker is usually initialized with a mutex that is
 278 // automatically acquired in order to do GC.  The function that
 279 // synchronizes using a GCMutexLocker may be called both during and between
 280 // GC's.  Thus, it must acquire the mutex if GC is not in progress, but not
 281 // if GC is in progress (since the mutex is already held on its behalf.)
 282 
 283 class GCMutexLocker: public StackObj {
 284 private:
 285   Monitor * _mutex;
 286   bool _locked;
 287 public:
 288   GCMutexLocker(Monitor * mutex);
 289   ~GCMutexLocker() { if (_locked) _mutex->unlock(); }
 290 };
 291 
 292 
 293 
 294 // A MutexUnlocker temporarily exits a previously
 295 // entered mutex for the scope which contains the unlocker.
 296 
 297 class MutexUnlocker: StackObj {
 298  private:
 299   Monitor * _mutex;
 300 
 301  public:
 302   MutexUnlocker(Monitor * mutex) {
 303     _mutex = mutex;
 304     _mutex->unlock();
 305   }
 306 
 307   ~MutexUnlocker() {
 308     _mutex->lock();
 309   }
 310 };
 311 
 312 // A MutexUnlockerEx temporarily exits a previously
 313 // entered mutex for the scope which contains the unlocker.
 314 
 315 class MutexUnlockerEx: StackObj {
 316  private:
 317   Monitor * _mutex;
 318   bool _no_safepoint_check;
 319 
 320  public:
 321   MutexUnlockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
 322     _mutex = mutex;
 323     _no_safepoint_check = no_safepoint_check;
 324     _mutex->unlock();
 325   }
 326 
 327   ~MutexUnlockerEx() {
 328     if (_no_safepoint_check == Mutex::_no_safepoint_check_flag) {
 329       _mutex->lock_without_safepoint_check();
 330     } else {
 331       _mutex->lock();
 332     }
 333   }
 334 };
 335 
 336 #ifndef PRODUCT
 337 //
 338 // A special MutexLocker that allows:
 339 //   - reentrant locking
 340 //   - locking out of order
 341 //
 342 // Only to be used for verify code, where we can relax out dead-lock
 343 // detection code a bit (unsafe, but probably ok). This code is NEVER to
 344 // be included in a product version.
 345 //
 346 class VerifyMutexLocker: StackObj {
 347  private:
 348   Monitor * _mutex;
 349   bool   _reentrant;
 350  public:
 351   VerifyMutexLocker(Monitor * mutex) {
 352     _mutex     = mutex;
 353     _reentrant = mutex->owned_by_self();
 354     if (!_reentrant) {
 355       // We temp. disable strict safepoint checking, while we require the lock
 356       FlagSetting fs(StrictSafepointChecks, false);
 357       _mutex->lock();
 358     }
 359   }
 360 
 361   ~VerifyMutexLocker() {
 362     if (!_reentrant) {
 363       _mutex->unlock();
 364     }
 365   }
 366 };
 367 
 368 #endif
 369 
 370 #endif // SHARE_VM_RUNTIME_MUTEXLOCKER_HPP