1 /*
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  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.
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  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  *
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 18  *
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 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