1 /* 2 * Copyright (c) 1997, 2025, 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_RUNTIME_MUTEXLOCKER_HPP 26 #define SHARE_RUNTIME_MUTEXLOCKER_HPP 27 28 #include "memory/allocation.hpp" 29 #include "runtime/flags/flagSetting.hpp" 30 #include "runtime/mutex.hpp" 31 32 class Thread; 33 34 // Mutexes used in the VM. 35 36 extern Mutex* NMethodState_lock; // a lock used to guard a compiled method state 37 extern Monitor* SystemDictionary_lock; // a lock on the system dictionary 38 extern Mutex* InvokeMethodTypeTable_lock; 39 extern Monitor* InvokeMethodIntrinsicTable_lock; 40 extern Mutex* SharedDictionary_lock; // a lock on the CDS shared dictionary 41 extern Monitor* ClassInitError_lock; // a lock on the class initialization error table 42 extern Mutex* Module_lock; // a lock on module and package related data structures 43 extern Mutex* CompiledIC_lock; // a lock used to guard compiled IC patching and access 44 extern Mutex* VMStatistic_lock; // a lock used to guard statistics count increment 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 synchronizing with threads entering/leaving JNI critical regions 48 extern Mutex* JvmtiThreadState_lock; // a lock on modification of JVMTI thread data 49 extern Monitor* EscapeBarrier_lock; // a lock to sync reallocating and relocking objects because of JVMTI access 50 extern Monitor* JvmtiVTMSTransition_lock; // a lock for Virtual Thread Mount State transition (VTMS transition) management 51 extern Mutex* JvmtiVThreadSuspend_lock; // a lock for virtual threads suspension 52 extern Monitor* Heap_lock; // a lock on the heap 53 #if INCLUDE_PARALLELGC 54 extern Mutex* PSOldGenExpand_lock; // a lock on expanding the heap 55 #endif 56 extern Mutex* AdapterHandlerLibrary_lock; // a lock on the AdapterHandlerLibrary 57 extern Mutex* SignatureHandlerLibrary_lock; // a lock on the SignatureHandlerLibrary 58 extern Mutex* VtableStubs_lock; // a lock on the VtableStubs 59 extern Mutex* SymbolArena_lock; // a lock on the symbol table arena 60 extern Monitor* StringDedup_lock; // a lock on the string deduplication facility 61 extern Mutex* StringDedupIntern_lock; // a lock on StringTable notification of StringDedup 62 extern Monitor* CodeCache_lock; // a lock on the CodeCache 63 extern Mutex* TouchedMethodLog_lock; // a lock on allocation of LogExecutedMethods info 64 extern Mutex* RetData_lock; // a lock on installation of RetData inside method data 65 extern Monitor* VMOperation_lock; // a lock on queue of vm_operations waiting to execute 66 extern Monitor* ThreadsLockThrottle_lock; // used by Thread start/exit to reduce competition for Threads_lock, 67 // so a VM thread calling a safepoint is prioritized 68 extern Monitor* Threads_lock; // a lock on the Threads table of active Java threads 69 // (also used by Safepoints too to block threads creation/destruction) 70 extern Mutex* NonJavaThreadsList_lock; // a lock on the NonJavaThreads list 71 extern Mutex* NonJavaThreadsListSync_lock; // a lock for NonJavaThreads list synchronization 72 extern Monitor* STS_lock; // used for joining/leaving SuspendibleThreadSet. 73 extern Mutex* MonitoringSupport_lock; // Protects updates to the serviceability memory pools and allocated memory high water mark. 74 extern Monitor* ConcurrentGCBreakpoints_lock; // Protects concurrent GC breakpoint management 75 extern Mutex* Compile_lock; // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc) 76 extern Monitor* MethodCompileQueue_lock; // a lock held when method compilations are enqueued, dequeued 77 extern Monitor* CompileThread_lock; // a lock held by compile threads during compilation system initialization 78 extern Monitor* Compilation_lock; // a lock used to pause compilation 79 extern Mutex* TrainingData_lock; // a lock used when accessing training records 80 extern Monitor* TrainingReplayQueue_lock; // a lock held when class are added/removed to the training replay queue 81 extern Monitor* CompileTaskWait_lock; // a lock held when CompileTasks are waited/notified 82 extern Mutex* CompileStatistics_lock; // a lock held when updating compilation statistics 83 extern Mutex* DirectivesStack_lock; // a lock held when mutating the dirstack and ref counting directives 84 extern Monitor* Terminator_lock; // a lock used to guard termination of the vm 85 extern Monitor* InitCompleted_lock; // a lock used to signal threads waiting on init completed 86 extern Monitor* BeforeExit_lock; // a lock used to guard cleanups and shutdown hooks 87 extern Monitor* Notify_lock; // a lock used to synchronize the start-up of the vm 88 extern Mutex* ExceptionCache_lock; // a lock used to synchronize exception cache updates 89 90 #ifndef PRODUCT 91 extern Mutex* FullGCALot_lock; // a lock to make FullGCALot MT safe 92 #endif // PRODUCT 93 94 #if INCLUDE_G1GC 95 extern Monitor* G1CGC_lock; // used for coordination between fore- & background G1 concurrent GC threads. 96 extern Mutex* G1FreeList_lock; // protects the G1 free region list during safepoints 97 extern Mutex* G1MarkStackChunkList_lock; // Protects access to the G1 global mark stack chunk list. 98 extern Mutex* G1MarkStackFreeList_lock; // Protects access to the G1 global mark stack free list. 99 extern Monitor* G1OldGCCount_lock; // in support of "concurrent" full gc 100 extern Mutex* G1OldSets_lock; // protects the G1 old region sets 101 extern Mutex* G1RareEvent_lock; // Synchronizes (rare) parallel GC operations. 102 extern Mutex* G1ReviseYoungLength_lock; // Protects access to young gen length revising operations. 103 extern Monitor* G1RootRegionScan_lock; // used to notify that the G1 CM threads have finished scanning the root regions 104 extern Mutex* G1Uncommit_lock; // protects the G1 uncommit list when not at safepoints 105 #endif 106 107 extern Mutex* RawMonitor_lock; 108 extern Mutex* PerfDataMemAlloc_lock; // a lock on the allocator for PerfData memory for performance data 109 extern Mutex* PerfDataManager_lock; // a long on access to PerfDataManager resources 110 111 extern Mutex* Management_lock; // a lock used to serialize JVM management 112 extern Monitor* MonitorDeflation_lock; // a lock used for monitor deflation thread operation 113 extern Monitor* Service_lock; // a lock used for service thread operation 114 extern Monitor* Notification_lock; // a lock used for notification thread operation 115 extern Monitor* PeriodicTask_lock; // protects the periodic task structure 116 extern Monitor* RedefineClasses_lock; // locks classes from parallel redefinition 117 extern Mutex* Verify_lock; // synchronize initialization of verify library 118 extern Monitor* ThreadsSMRDelete_lock; // Used by ThreadsSMRSupport to take pressure off the Threads_lock 119 extern Mutex* ThreadIdTableCreate_lock; // Used by ThreadIdTable to lazily create the thread id table 120 extern Mutex* SharedDecoder_lock; // serializes access to the decoder during normal (not error reporting) use 121 extern Mutex* DCmdFactory_lock; // serialize access to DCmdFactory information 122 extern Mutex* NMTQuery_lock; // serialize NMT Dcmd queries 123 extern Mutex* NMTCompilationCostHistory_lock; // guards NMT compilation cost history 124 extern Mutex* NmtVirtualMemory_lock; // guards NMT virtual memory updates 125 #if INCLUDE_CDS 126 #if INCLUDE_JVMTI 127 extern Mutex* CDSClassFileStream_lock; // FileMapInfo::open_stream_for_jvmti 128 #endif 129 extern Mutex* DumpTimeTable_lock; // SystemDictionaryShared::_dumptime_table 130 extern Mutex* CDSLambda_lock; // LambdaProxyClassDictionary::find_lambda_proxy_class 131 extern Mutex* DumpRegion_lock; // Symbol::operator new(size_t sz, int len) 132 extern Mutex* ClassListFile_lock; // ClassListWriter() 133 extern Mutex* UnregisteredClassesTable_lock; // UnregisteredClassesTableTable 134 extern Mutex* LambdaFormInvokers_lock; // Protecting LambdaFormInvokers::_lambdaform_lines 135 extern Mutex* ScratchObjects_lock; // Protecting _scratch_xxx_table in heapShared.cpp 136 extern Mutex* FinalImageRecipes_lock; // Protecting the tables used by FinalImageRecipes. 137 #endif // INCLUDE_CDS 138 #if INCLUDE_JFR 139 extern Mutex* JfrStacktrace_lock; // used to guard access to the JFR stacktrace table 140 extern Monitor* JfrMsg_lock; // protects JFR messaging 141 extern Mutex* JfrBuffer_lock; // protects JFR buffer operations 142 #endif 143 144 extern Mutex* Metaspace_lock; // protects Metaspace virtualspace and chunk expansions 145 extern Monitor* MetaspaceCritical_lock; // synchronizes failed metaspace allocations that risk throwing metaspace OOM 146 extern Mutex* ClassLoaderDataGraph_lock; // protects CLDG list, needed for concurrent unloading 147 148 149 extern Mutex* CodeHeapStateAnalytics_lock; // lock print functions against concurrent analyze functions. 150 // Only used locally in PrintCodeCacheLayout processing. 151 152 extern Mutex* ExternalsRecorder_lock; // used to guard access to the external addresses table 153 154 extern Mutex* AOTCodeCStrings_lock; // used to guard access to the AOT code C strings table 155 156 extern Monitor* ContinuationRelativize_lock; 157 158 #if INCLUDE_JVMCI 159 extern Monitor* JVMCI_lock; // protects global JVMCI critical sections 160 extern Monitor* JVMCIRuntime_lock; // protects critical sections for a specific JVMCIRuntime object 161 #endif 162 163 extern Mutex* Bootclasspath_lock; 164 165 extern Mutex* tty_lock; // lock to synchronize output. 166 167 // A MutexLocker provides mutual exclusion with respect to a given mutex 168 // for the scope which contains the locker. The lock is an OS lock, not 169 // an object lock, and the two do not interoperate. Do not use Mutex-based 170 // locks to lock on Java objects, because they will not be respected if a 171 // that object is locked using the Java locking mechanism. 172 // 173 // NOTE WELL!! 174 // 175 // See orderAccess.hpp. We assume throughout the VM that MutexLocker's 176 // and friends constructors do a fence, a lock and an acquire *in that 177 // order*. And that their destructors do a release and unlock, in *that* 178 // order. If their implementations change such that these assumptions 179 // are violated, a whole lot of code will break. 180 181 // for debugging: check that we're already owning this lock (or are at a safepoint / handshake) 182 #ifdef ASSERT 183 void assert_locked_or_safepoint(const Mutex* lock); 184 void assert_lock_strong(const Mutex* lock); 185 #else 186 #define assert_locked_or_safepoint(lock) 187 #define assert_lock_strong(lock) 188 #endif 189 190 // Internal implementation. Skips on null Mutex. 191 // Subclasses enforce stronger invariants. 192 class MutexLockerImpl: public StackObj { 193 protected: 194 Mutex* _mutex; 195 196 MutexLockerImpl(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) : 197 _mutex(mutex) { 198 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag; 199 if (_mutex != nullptr) { 200 if (no_safepoint_check) { 201 _mutex->lock_without_safepoint_check(); 202 } else { 203 _mutex->lock(); 204 } 205 } 206 } 207 208 MutexLockerImpl(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) : 209 _mutex(mutex) { 210 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag; 211 if (_mutex != nullptr) { 212 if (no_safepoint_check) { 213 _mutex->lock_without_safepoint_check(thread); 214 } else { 215 _mutex->lock(thread); 216 } 217 } 218 } 219 220 ~MutexLockerImpl() { 221 if (_mutex != nullptr) { 222 assert_lock_strong(_mutex); 223 _mutex->unlock(); 224 } 225 } 226 227 public: 228 static void post_initialize(); 229 }; 230 231 // Simplest mutex locker. 232 // Does not allow null mutexes. 233 class MutexLocker: public MutexLockerImpl { 234 public: 235 MutexLocker(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) : 236 MutexLockerImpl(mutex, flag) { 237 assert(mutex != nullptr, "null mutex not allowed"); 238 } 239 240 MutexLocker(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) : 241 MutexLockerImpl(thread, mutex, flag) { 242 assert(mutex != nullptr, "null mutex not allowed"); 243 } 244 }; 245 246 // Conditional mutex locker. 247 // Like MutexLocker above, but only locks when condition is true. 248 class ConditionalMutexLocker: public MutexLockerImpl { 249 public: 250 ConditionalMutexLocker(Mutex* mutex, bool condition, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) : 251 MutexLockerImpl(condition ? mutex : nullptr, flag) { 252 assert(!condition || mutex != nullptr, "null mutex not allowed when locking"); 253 } 254 255 ConditionalMutexLocker(Thread* thread, Mutex* mutex, bool condition, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) : 256 MutexLockerImpl(thread, condition ? mutex : nullptr, flag) { 257 assert(!condition || mutex != nullptr, "null mutex not allowed when locking"); 258 } 259 }; 260 261 // A MonitorLocker is like a MutexLocker above, except it allows 262 // wait/notify as well which are delegated to the underlying Monitor. 263 // It also disallows null. 264 class MonitorLocker: public MutexLockerImpl { 265 Mutex::SafepointCheckFlag _flag; 266 267 protected: 268 Monitor* as_monitor() const { 269 return static_cast<Monitor*>(_mutex); 270 } 271 272 public: 273 MonitorLocker(Monitor* monitor, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) : 274 MutexLockerImpl(monitor, flag), _flag(flag) { 275 // Superclass constructor did locking 276 assert(monitor != nullptr, "null monitor not allowed"); 277 } 278 279 MonitorLocker(Thread* thread, Monitor* monitor, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) : 280 MutexLockerImpl(thread, monitor, flag), _flag(flag) { 281 // Superclass constructor did locking 282 assert(monitor != nullptr, "null monitor not allowed"); 283 } 284 285 bool wait(int64_t timeout = 0) { 286 return _flag == Mutex::_safepoint_check_flag ? 287 as_monitor()->wait(timeout) : as_monitor()->wait_without_safepoint_check(timeout); 288 } 289 290 void notify_all() { 291 as_monitor()->notify_all(); 292 } 293 294 void notify() { 295 as_monitor()->notify(); 296 } 297 }; 298 299 300 // A GCMutexLocker is usually initialized with a mutex that is 301 // automatically acquired in order to do GC. The function that 302 // synchronizes using a GCMutexLocker may be called both during and between 303 // GC's. Thus, it must acquire the mutex if GC is not in progress, but not 304 // if GC is in progress (since the mutex is already held on its behalf.) 305 306 class GCMutexLocker: public StackObj { 307 private: 308 Mutex* _mutex; 309 bool _locked; 310 public: 311 GCMutexLocker(Mutex* mutex); 312 ~GCMutexLocker() { if (_locked) _mutex->unlock(); } 313 }; 314 315 // A MutexUnlocker temporarily exits a previously 316 // entered mutex for the scope which contains the unlocker. 317 318 class MutexUnlocker: StackObj { 319 private: 320 Mutex* _mutex; 321 bool _no_safepoint_check; 322 323 public: 324 MutexUnlocker(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) : 325 _mutex(mutex), 326 _no_safepoint_check(flag == Mutex::_no_safepoint_check_flag) { 327 _mutex->unlock(); 328 } 329 330 ~MutexUnlocker() { 331 if (_no_safepoint_check) { 332 _mutex->lock_without_safepoint_check(); 333 } else { 334 _mutex->lock(); 335 } 336 } 337 }; 338 339 // Instance of a RecursiveLock that may be held through Java heap allocation, which may include calls to Java, 340 // and JNI event notification for resource exhaustion for metaspace or heap. 341 extern RecursiveMutex* MultiArray_lock; 342 343 // RAII locker for a RecursiveMutex. See comments in mutex.hpp for more information. 344 class RecursiveLocker { 345 RecursiveMutex* _lock; 346 Thread* _thread; 347 public: 348 RecursiveLocker(RecursiveMutex* lock, Thread* current) : _lock(lock), _thread(current) { 349 _lock->lock(_thread); 350 } 351 ~RecursiveLocker() { 352 _lock->unlock(_thread); 353 } 354 }; 355 356 #endif // SHARE_RUNTIME_MUTEXLOCKER_HPP