1 /*
   2  * Copyright (c) 1997, 2015, 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
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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/mutex.hpp"
  30 #ifdef TARGET_OS_FAMILY_linux
  31 # include "os_linux.inline.hpp"
  32 #endif
  33 #ifdef TARGET_OS_FAMILY_solaris
  34 # include "os_solaris.inline.hpp"
  35 #endif
  36 #ifdef TARGET_OS_FAMILY_windows
  37 # include "os_windows.inline.hpp"
  38 #endif
  39 #ifdef TARGET_OS_FAMILY_aix
  40 # include "os_aix.inline.hpp"
  41 #endif
  42 #ifdef TARGET_OS_FAMILY_bsd
  43 # include "os_bsd.inline.hpp"
  44 #endif
  45 
  46 // Mutexes used in the VM.
  47 
  48 extern Mutex*   Patching_lock;                   // a lock used to guard code patching of compiled code
  49 extern Monitor* SystemDictionary_lock;           // a lock on the system dictonary
  50 extern Mutex*   PackageTable_lock;               // a lock on the class loader package table
  51 extern Mutex*   CompiledIC_lock;                 // a lock used to guard compiled IC patching and access
  52 extern Mutex*   InlineCacheBuffer_lock;          // a lock used to guard the InlineCacheBuffer
  53 extern Mutex*   VMStatistic_lock;                // a lock used to guard statistics count increment
  54 extern Mutex*   JNIGlobalHandle_lock;            // a lock on creating JNI global handles
  55 extern Mutex*   JNIHandleBlockFreeList_lock;     // a lock on the JNI handle block free list
  56 extern Mutex*   MemberNameTable_lock;            // a lock on the MemberNameTable updates
  57 extern Mutex*   JmethodIdCreation_lock;          // a lock on creating JNI method identifiers
  58 extern Mutex*   JfieldIdCreation_lock;           // a lock on creating JNI static field identifiers
  59 extern Monitor* JNICritical_lock;                // a lock used while entering and exiting JNI critical regions, allows GC to sometimes get in
  60 extern Mutex*   JvmtiThreadState_lock;           // a lock on modification of JVMTI thread data
  61 extern Monitor* JvmtiPendingEvent_lock;          // a lock on the JVMTI pending events list
  62 extern Monitor* Heap_lock;                       // a lock on the heap
  63 extern Mutex*   ExpandHeap_lock;                 // a lock on expanding the heap
  64 extern Mutex*   AdapterHandlerLibrary_lock;      // a lock on the AdapterHandlerLibrary
  65 extern Mutex*   SignatureHandlerLibrary_lock;    // a lock on the SignatureHandlerLibrary
  66 extern Mutex*   VtableStubs_lock;                // a lock on the VtableStubs
  67 extern Mutex*   SymbolTable_lock;                // a lock on the symbol table
  68 extern Mutex*   StringTable_lock;                // a lock on the interned string table
  69 extern Monitor* StringDedupQueue_lock;           // a lock on the string deduplication queue
  70 extern Mutex*   StringDedupTable_lock;           // a lock on the string deduplication table
  71 extern Mutex*   CodeCache_lock;                  // a lock on the CodeCache, rank is special, use MutexLockerEx
  72 extern Mutex*   MethodData_lock;                 // a lock on installation of method data
  73 extern Mutex*   RetData_lock;                    // a lock on installation of RetData inside method data
  74 extern Mutex*   DerivedPointerTableGC_lock;      // a lock to protect the derived pointer table
  75 extern Monitor* VMOperationQueue_lock;           // a lock on queue of vm_operations waiting to execute
  76 extern Monitor* VMOperationRequest_lock;         // a lock on Threads waiting for a vm_operation to terminate
  77 extern Monitor* Safepoint_lock;                  // a lock used by the safepoint abstraction
  78 extern Monitor* Threads_lock;                    // a lock on the Threads table of active Java threads
  79                                                  // (also used by Safepoints too to block threads creation/destruction)
  80 extern Monitor* CGC_lock;                        // used for coordination between
  81                                                  // fore- & background GC threads.
  82 extern Monitor* STS_lock;                        // used for joining/leaving SuspendibleThreadSet.
  83 extern Monitor* SLT_lock;                        // used in CMS GC for acquiring PLL
  84 extern Monitor* iCMS_lock;                       // CMS incremental mode start/stop notification
  85 extern Monitor* FullGCCount_lock;                // in support of "concurrent" full gc
  86 extern Monitor* CMark_lock;                      // used for concurrent mark thread coordination
  87 extern Mutex*   CMRegionStack_lock;              // used for protecting accesses to the CM region stack
  88 extern Mutex*   SATB_Q_FL_lock;                  // Protects SATB Q
  89                                                  // buffer free list.
  90 extern Monitor* SATB_Q_CBL_mon;                  // Protects SATB Q
  91                                                  // completed buffer queue.
  92 extern Mutex*   Shared_SATB_Q_lock;              // Lock protecting SATB
  93                                                  // queue shared by
  94                                                  // non-Java threads.
  95 
  96 extern Mutex*   DirtyCardQ_FL_lock;              // Protects dirty card Q
  97                                                  // buffer free list.
  98 extern Monitor* DirtyCardQ_CBL_mon;              // Protects dirty card Q
  99                                                  // completed buffer queue.
 100 extern Mutex*   Shared_DirtyCardQ_lock;          // Lock protecting dirty card
 101                                                  // queue shared by
 102                                                  // non-Java threads.
 103                                                  // (see option ExplicitGCInvokesConcurrent)
 104 extern Mutex*   ParGCRareEvent_lock;             // Synchronizes various (rare) parallel GC ops.
 105 extern Mutex*   EvacFailureStack_lock;           // guards the evac failure scan stack
 106 extern Mutex*   Compile_lock;                    // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
 107 extern Monitor* MethodCompileQueue_lock;         // a lock held when method compilations are enqueued, dequeued
 108 extern Monitor* CompileThread_lock;              // a lock held by compile threads during compilation system initialization
 109 extern Mutex*   CompileTaskAlloc_lock;           // a lock held when CompileTasks are allocated
 110 extern Mutex*   CompileStatistics_lock;          // a lock held when updating compilation statistics
 111 extern Mutex*   MultiArray_lock;                 // a lock used to guard allocation of multi-dim arrays
 112 extern Monitor* Terminator_lock;                 // a lock used to guard termination of the vm
 113 extern Monitor* BeforeExit_lock;                 // a lock used to guard cleanups and shutdown hooks
 114 extern Monitor* Notify_lock;                     // a lock used to synchronize the start-up of the vm
 115 extern Monitor* Interrupt_lock;                  // a lock used for condition variable mediated interrupt processing
 116 extern Monitor* ProfileVM_lock;                  // a lock used for profiling the VMThread
 117 extern Mutex*   ProfilePrint_lock;               // a lock used to serialize the printing of profiles
 118 extern Mutex*   ExceptionCache_lock;             // a lock used to synchronize exception cache updates
 119 extern Mutex*   OsrList_lock;                    // a lock used to serialize access to OSR queues
 120 
 121 #ifndef PRODUCT
 122 extern Mutex*   FullGCALot_lock;                 // a lock to make FullGCALot MT safe
 123 #endif // PRODUCT
 124 extern Mutex*   Debug1_lock;                     // A bunch of pre-allocated locks that can be used for tracing
 125 extern Mutex*   Debug2_lock;                     // down synchronization related bugs!
 126 extern Mutex*   Debug3_lock;
 127 
 128 extern Mutex*   RawMonitor_lock;
 129 extern Mutex*   PerfDataMemAlloc_lock;           // a lock on the allocator for PerfData memory for performance data
 130 extern Mutex*   PerfDataManager_lock;            // a long on access to PerfDataManager resources
 131 extern Mutex*   ParkerFreeList_lock;
 132 extern Mutex*   OopMapCacheAlloc_lock;           // protects allocation of oop_map caches
 133 
 134 extern Mutex*   FreeList_lock;                   // protects the free region list during safepoints
 135 extern Monitor* SecondaryFreeList_lock;          // protects the secondary free region list
 136 extern Mutex*   OldSets_lock;                    // protects the old region sets
 137 extern Monitor* RootRegionScan_lock;             // used to notify that the CM threads have finished scanning the IM snapshot regions
 138 extern Mutex*   MMUTracker_lock;                 // protects the MMU
 139                                                  // tracker data structures
 140 
 141 extern Mutex*   Management_lock;                 // a lock used to serialize JVM management
 142 extern Monitor* Service_lock;                    // a lock used for service thread operation
 143 extern Monitor* PeriodicTask_lock;               // protects the periodic task structure
 144 
 145 #if INCLUDE_JFR
 146 extern Mutex*   JfrStacktrace_lock;              // used to guard access to the JFR stacktrace table
 147 extern Monitor* JfrMsg_lock;                     // protects JFR messaging
 148 extern Mutex*   JfrBuffer_lock;                  // protects JFR buffer operations
 149 extern Mutex*   JfrStream_lock;                  // protects JFR stream access
 150 extern Mutex*   JfrThreadGroups_lock;            // protects JFR access to Thread Groups
 151 
 152 #ifndef SUPPORTS_NATIVE_CX8
 153 extern Mutex*   JfrCounters_lock;                // provides atomic updates of JFR counters
 154 #endif
 155 
 156 #endif
 157 
 158 #ifndef SUPPORTS_NATIVE_CX8
 159 extern Mutex*   UnsafeJlong_lock;                // provides Unsafe atomic updates to jlongs on platforms that don't support cx8
 160 #endif
 161 
 162 // A MutexLocker provides mutual exclusion with respect to a given mutex
 163 // for the scope which contains the locker.  The lock is an OS lock, not
 164 // an object lock, and the two do not interoperate.  Do not use Mutex-based
 165 // locks to lock on Java objects, because they will not be respected if a
 166 // that object is locked using the Java locking mechanism.
 167 //
 168 //                NOTE WELL!!
 169 //
 170 // See orderAccess.hpp.  We assume throughout the VM that MutexLocker's
 171 // and friends constructors do a fence, a lock and an acquire *in that
 172 // order*.  And that their destructors do a release and unlock, in *that*
 173 // order.  If their implementations change such that these assumptions
 174 // are violated, a whole lot of code will break.
 175 
 176 // Print all mutexes/monitors that are currently owned by a thread; called
 177 // by fatal error handler.
 178 void print_owned_locks_on_error(outputStream* st);
 179 
 180 char *lock_name(Mutex *mutex);
 181 
 182 class MutexLocker: StackObj {
 183  private:
 184   Monitor * _mutex;
 185  public:
 186   MutexLocker(Monitor * mutex) {
 187     assert(mutex->rank() != Mutex::special,
 188       "Special ranked mutex should only use MutexLockerEx");
 189     _mutex = mutex;
 190     _mutex->lock();
 191   }
 192 
 193   // Overloaded constructor passing current thread
 194   MutexLocker(Monitor * mutex, Thread *thread) {
 195     assert(mutex->rank() != Mutex::special,
 196       "Special ranked mutex should only use MutexLockerEx");
 197     _mutex = mutex;
 198     _mutex->lock(thread);
 199   }
 200 
 201   ~MutexLocker() {
 202     _mutex->unlock();
 203   }
 204 
 205 };
 206 
 207 // for debugging: check that we're already owning this lock (or are at a safepoint)
 208 #ifdef ASSERT
 209 void assert_locked_or_safepoint(const Monitor * lock);
 210 void assert_lock_strong(const Monitor * lock);
 211 #else
 212 #define assert_locked_or_safepoint(lock)
 213 #define assert_lock_strong(lock)
 214 #endif
 215 
 216 // A MutexLockerEx behaves like a MutexLocker when its constructor is
 217 // called with a Mutex.  Unlike a MutexLocker, its constructor can also be
 218 // called with NULL, in which case the MutexLockerEx is a no-op.  There
 219 // is also a corresponding MutexUnlockerEx.  We want to keep the
 220 // basic MutexLocker as fast as possible.  MutexLockerEx can also lock
 221 // without safepoint check.
 222 
 223 class MutexLockerEx: public StackObj {
 224  private:
 225   Monitor * _mutex;
 226  public:
 227   MutexLockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
 228     _mutex = mutex;
 229     if (_mutex != NULL) {
 230       assert(mutex->rank() > Mutex::special || no_safepoint_check,
 231         "Mutexes with rank special or lower should not do safepoint checks");
 232       if (no_safepoint_check)
 233         _mutex->lock_without_safepoint_check();
 234       else
 235         _mutex->lock();
 236     }
 237   }
 238 
 239   ~MutexLockerEx() {
 240     if (_mutex != NULL) {
 241       _mutex->unlock();
 242     }
 243   }
 244 };
 245 
 246 // A MonitorLockerEx is like a MutexLockerEx above, except it takes
 247 // a possibly null Monitor, and allows wait/notify as well which are
 248 // delegated to the underlying Monitor.
 249 
 250 class MonitorLockerEx: public MutexLockerEx {
 251  private:
 252   Monitor * _monitor;
 253  public:
 254   MonitorLockerEx(Monitor* monitor,
 255                   bool no_safepoint_check = !Mutex::_no_safepoint_check_flag):
 256     MutexLockerEx(monitor, no_safepoint_check),
 257     _monitor(monitor) {
 258     // Superclass constructor did locking
 259   }
 260 
 261   ~MonitorLockerEx() {
 262     #ifdef ASSERT
 263       if (_monitor != NULL) {
 264         assert_lock_strong(_monitor);
 265       }
 266     #endif  // ASSERT
 267     // Superclass destructor will do unlocking
 268   }
 269 
 270   bool wait(bool no_safepoint_check = !Mutex::_no_safepoint_check_flag,
 271             long timeout = 0,
 272             bool as_suspend_equivalent = !Mutex::_as_suspend_equivalent_flag) {
 273     if (_monitor != NULL) {
 274       return _monitor->wait(no_safepoint_check, timeout, as_suspend_equivalent);
 275     }
 276     return false;
 277   }
 278 
 279   bool notify_all() {
 280     if (_monitor != NULL) {
 281       return _monitor->notify_all();
 282     }
 283     return true;
 284   }
 285 
 286   bool notify() {
 287     if (_monitor != NULL) {
 288       return _monitor->notify();
 289     }
 290     return true;
 291   }
 292 };
 293 
 294 
 295 
 296 // A GCMutexLocker is usually initialized with a mutex that is
 297 // automatically acquired in order to do GC.  The function that
 298 // synchronizes using a GCMutexLocker may be called both during and between
 299 // GC's.  Thus, it must acquire the mutex if GC is not in progress, but not
 300 // if GC is in progress (since the mutex is already held on its behalf.)
 301 
 302 class GCMutexLocker: public StackObj {
 303 private:
 304   Monitor * _mutex;
 305   bool _locked;
 306 public:
 307   GCMutexLocker(Monitor * mutex);
 308   ~GCMutexLocker() { if (_locked) _mutex->unlock(); }
 309 };
 310 
 311 
 312 
 313 // A MutexUnlocker temporarily exits a previously
 314 // entered mutex for the scope which contains the unlocker.
 315 
 316 class MutexUnlocker: StackObj {
 317  private:
 318   Monitor * _mutex;
 319 
 320  public:
 321   MutexUnlocker(Monitor * mutex) {
 322     _mutex = mutex;
 323     _mutex->unlock();
 324   }
 325 
 326   ~MutexUnlocker() {
 327     _mutex->lock();
 328   }
 329 };
 330 
 331 // A MutexUnlockerEx temporarily exits a previously
 332 // entered mutex for the scope which contains the unlocker.
 333 
 334 class MutexUnlockerEx: StackObj {
 335  private:
 336   Monitor * _mutex;
 337   bool _no_safepoint_check;
 338 
 339  public:
 340   MutexUnlockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
 341     _mutex = mutex;
 342     _no_safepoint_check = no_safepoint_check;
 343     _mutex->unlock();
 344   }
 345 
 346   ~MutexUnlockerEx() {
 347     if (_no_safepoint_check == Mutex::_no_safepoint_check_flag) {
 348       _mutex->lock_without_safepoint_check();
 349     } else {
 350       _mutex->lock();
 351     }
 352   }
 353 };
 354 
 355 #ifndef PRODUCT
 356 //
 357 // A special MutexLocker that allows:
 358 //   - reentrant locking
 359 //   - locking out of order
 360 //
 361 // Only too be used for verify code, where we can relaxe out dead-lock
 362 // dection code a bit (unsafe, but probably ok). This code is NEVER to
 363 // be included in a product version.
 364 //
 365 class VerifyMutexLocker: StackObj {
 366  private:
 367   Monitor * _mutex;
 368   bool   _reentrant;
 369  public:
 370   VerifyMutexLocker(Monitor * mutex) {
 371     _mutex     = mutex;
 372     _reentrant = mutex->owned_by_self();
 373     if (!_reentrant) {
 374       // We temp. diable strict safepoint checking, while we require the lock
 375       FlagSetting fs(StrictSafepointChecks, false);
 376       _mutex->lock();
 377     }
 378   }
 379 
 380   ~VerifyMutexLocker() {
 381     if (!_reentrant) {
 382       _mutex->unlock();
 383     }
 384   }
 385 };
 386 
 387 #endif
 388 
 389 #endif // SHARE_VM_RUNTIME_MUTEXLOCKER_HPP