1 /*
2 * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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).
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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 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* 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 Monitor* Heap_lock; // a lock on the heap
52 #ifdef INCLUDE_PARALLELGC
53 extern Mutex* PSOldGenExpand_lock; // a lock on expanding the heap
54 #endif
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* SymbolArena_lock; // a lock on the symbol table arena
59 extern Monitor* StringDedup_lock; // a lock on the string deduplication facility
60 extern Mutex* StringDedupIntern_lock; // a lock on StringTable notification of StringDedup
61 extern Monitor* CodeCache_lock; // a lock on the CodeCache
62 extern Mutex* TouchedMethodLog_lock; // a lock on allocation of LogExecutedMethods info
63 extern Mutex* RetData_lock; // a lock on installation of RetData inside method data
64 extern Monitor* VMOperation_lock; // a lock on queue of vm_operations waiting to execute
65 extern Monitor* ThreadsLockThrottle_lock; // used by Thread start/exit to reduce competition for Threads_lock,
66 // so a VM thread calling a safepoint is prioritized
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 Mutex* NonJavaThreadsList_lock; // a lock on the NonJavaThreads list
70 extern Mutex* NonJavaThreadsListSync_lock; // a lock for NonJavaThreads list synchronization
71 extern Monitor* CGC_lock; // used for coordination between
72 // fore- & background GC threads.
73 extern Monitor* STS_lock; // used for joining/leaving SuspendibleThreadSet.
74 extern Monitor* G1OldGCCount_lock; // in support of "concurrent" full gc
75 extern Mutex* G1RareEvent_lock; // Synchronizes (rare) parallel GC operations.
76 extern Mutex* G1DetachedRefinementStats_lock; // Lock protecting detached refinement stats
77 extern Mutex* MarkStackFreeList_lock; // Protects access to the global mark stack free list.
78 extern Mutex* MarkStackChunkList_lock; // Protects access to the global mark stack chunk list.
79 extern Mutex* MonitoringSupport_lock; // Protects updates to the serviceability memory pools and allocated memory high water mark.
80 extern Monitor* ConcurrentGCBreakpoints_lock; // Protects concurrent GC breakpoint management
81 extern Mutex* Compile_lock; // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
82 extern Monitor* MethodCompileQueue_lock; // a lock held when method compilations are enqueued, dequeued
83 extern Monitor* CompileThread_lock; // a lock held by compile threads during compilation system initialization
84 extern Monitor* Compilation_lock; // a lock used to pause compilation
85 extern Mutex* CompileTaskAlloc_lock; // a lock held when CompileTasks are allocated
86 extern Mutex* CompileStatistics_lock; // a lock held when updating compilation statistics
87 extern Mutex* DirectivesStack_lock; // a lock held when mutating the dirstack and ref counting directives
88 extern Monitor* Terminator_lock; // a lock used to guard termination of the vm
89 extern Monitor* InitCompleted_lock; // a lock used to signal threads waiting on init completed
90 extern Monitor* BeforeExit_lock; // a lock used to guard cleanups and shutdown hooks
91 extern Monitor* Notify_lock; // a lock used to synchronize the start-up of the vm
92 extern Mutex* ExceptionCache_lock; // a lock used to synchronize exception cache updates
93
94 #ifndef PRODUCT
95 extern Mutex* FullGCALot_lock; // a lock to make FullGCALot MT safe
96 #endif // PRODUCT
97
98 extern Mutex* RawMonitor_lock;
99 extern Mutex* PerfDataMemAlloc_lock; // a lock on the allocator for PerfData memory for performance data
100 extern Mutex* PerfDataManager_lock; // a long on access to PerfDataManager resources
101
102 extern Mutex* FreeList_lock; // protects the free region list during safepoints
103 extern Mutex* OldSets_lock; // protects the old region sets
104 extern Mutex* Uncommit_lock; // protects the uncommit list when not at safepoints
105 extern Monitor* RootRegionScan_lock; // used to notify that the CM threads have finished scanning the IM snapshot regions
106
107 extern Mutex* Management_lock; // a lock used to serialize JVM management
108 extern Monitor* MonitorDeflation_lock; // a lock used for monitor deflation thread operation
109 extern Monitor* Service_lock; // a lock used for service thread operation
110 extern Monitor* Notification_lock; // a lock used for notification thread operation
111 extern Monitor* PeriodicTask_lock; // protects the periodic task structure
112 extern Monitor* RedefineClasses_lock; // locks classes from parallel redefinition
113 extern Mutex* Verify_lock; // synchronize initialization of verify library
114 extern Monitor* ThreadsSMRDelete_lock; // Used by ThreadsSMRSupport to take pressure off the Threads_lock
115 extern Mutex* ThreadIdTableCreate_lock; // Used by ThreadIdTable to lazily create the thread id table
116 extern Mutex* SharedDecoder_lock; // serializes access to the decoder during normal (not error reporting) use
117 extern Mutex* DCmdFactory_lock; // serialize access to DCmdFactory information
118 extern Mutex* NMTQuery_lock; // serialize NMT Dcmd queries
119 extern Mutex* NMTCompilationCostHistory_lock; // guards NMT compilation cost history
120 #if INCLUDE_CDS
121 #if INCLUDE_JVMTI
122 extern Mutex* CDSClassFileStream_lock; // FileMapInfo::open_stream_for_jvmti
123 #endif
124 extern Mutex* DumpTimeTable_lock; // SystemDictionaryShared::_dumptime_table
125 extern Mutex* CDSLambda_lock; // SystemDictionaryShared::get_shared_lambda_proxy_class
126 extern Mutex* DumpRegion_lock; // Symbol::operator new(size_t sz, int len)
127 extern Mutex* ClassListFile_lock; // ClassListWriter()
128 extern Mutex* UnregisteredClassesTable_lock; // UnregisteredClassesTableTable
129 extern Mutex* LambdaFormInvokers_lock; // Protecting LambdaFormInvokers::_lambdaform_lines
130 extern Mutex* ScratchObjects_lock; // Protecting _scratch_xxx_table in heapShared.cpp
131 #endif // INCLUDE_CDS
132 #if INCLUDE_JFR
133 extern Mutex* JfrStacktrace_lock; // used to guard access to the JFR stacktrace table
134 extern Monitor* JfrMsg_lock; // protects JFR messaging
135 extern Mutex* JfrBuffer_lock; // protects JFR buffer operations
136 extern Monitor* JfrThreadSampler_lock; // used to suspend/resume JFR thread sampler
137 #endif
138
139 extern Mutex* Metaspace_lock; // protects Metaspace virtualspace and chunk expansions
140 extern Monitor* MetaspaceCritical_lock; // synchronizes failed metaspace allocations that risk throwing metaspace OOM
141 extern Mutex* ClassLoaderDataGraph_lock; // protects CLDG list, needed for concurrent unloading
142
143
144 extern Mutex* CodeHeapStateAnalytics_lock; // lock print functions against concurrent analyze functions.
145 // Only used locally in PrintCodeCacheLayout processing.
146
147 extern Mutex* ExternalsRecorder_lock; // used to guard access to the external addresses table
148
149 extern Monitor* ContinuationRelativize_lock;
150
151 #if INCLUDE_JVMCI
152 extern Monitor* JVMCI_lock; // protects global JVMCI critical sections
153 extern Monitor* JVMCIRuntime_lock; // protects critical sections for a specific JVMCIRuntime object
154 #endif
155
156 extern Mutex* Bootclasspath_lock;
157
158 extern Mutex* tty_lock; // lock to synchronize output.
159
160 // A MutexLocker provides mutual exclusion with respect to a given mutex
161 // for the scope which contains the locker. The lock is an OS lock, not
162 // an object lock, and the two do not interoperate. Do not use Mutex-based
163 // locks to lock on Java objects, because they will not be respected if a
164 // that object is locked using the Java locking mechanism.
165 //
166 // NOTE WELL!!
167 //
168 // See orderAccess.hpp. We assume throughout the VM that MutexLocker's
169 // and friends constructors do a fence, a lock and an acquire *in that
170 // order*. And that their destructors do a release and unlock, in *that*
171 // order. If their implementations change such that these assumptions
172 // are violated, a whole lot of code will break.
173
174 // for debugging: check that we're already owning this lock (or are at a safepoint / handshake)
175 #ifdef ASSERT
176 void assert_locked_or_safepoint(const Mutex* lock);
177 void assert_lock_strong(const Mutex* lock);
178 #else
179 #define assert_locked_or_safepoint(lock)
180 #define assert_lock_strong(lock)
181 #endif
182
183 // Internal implementation. Skips on null Mutex.
184 // Subclasses enforce stronger invariants.
185 class MutexLockerImpl: public StackObj {
186 protected:
187 Mutex* _mutex;
188
189 MutexLockerImpl(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
190 _mutex(mutex) {
191 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
192 if (_mutex != nullptr) {
193 if (no_safepoint_check) {
194 _mutex->lock_without_safepoint_check();
195 } else {
196 _mutex->lock();
197 }
198 }
199 }
200
201 MutexLockerImpl(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
202 _mutex(mutex) {
203 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
204 if (_mutex != nullptr) {
205 if (no_safepoint_check) {
206 _mutex->lock_without_safepoint_check(thread);
207 } else {
208 _mutex->lock(thread);
209 }
210 }
211 }
212
213 ~MutexLockerImpl() {
214 if (_mutex != nullptr) {
215 assert_lock_strong(_mutex);
216 _mutex->unlock();
217 }
218 }
219
220 public:
221 static void post_initialize();
222 };
223
224 // Simplest mutex locker.
225 // Does not allow null mutexes.
226 class MutexLocker: public MutexLockerImpl {
227 public:
228 MutexLocker(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
229 MutexLockerImpl(mutex, flag) {
230 assert(mutex != nullptr, "null mutex not allowed");
231 }
232
233 MutexLocker(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
234 MutexLockerImpl(thread, mutex, flag) {
235 assert(mutex != nullptr, "null mutex not allowed");
236 }
237 };
238
239 // Conditional mutex locker.
240 // Like MutexLocker above, but only locks when condition is true.
241 class ConditionalMutexLocker: public MutexLockerImpl {
242 public:
243 ConditionalMutexLocker(Mutex* mutex, bool condition, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
244 MutexLockerImpl(condition ? mutex : nullptr, flag) {
245 assert(!condition || mutex != nullptr, "null mutex not allowed when locking");
246 }
247
248 ConditionalMutexLocker(Thread* thread, Mutex* mutex, bool condition, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
249 MutexLockerImpl(thread, condition ? mutex : nullptr, flag) {
250 assert(!condition || mutex != nullptr, "null mutex not allowed when locking");
251 }
252 };
253
254 // A MonitorLocker is like a MutexLocker above, except it allows
255 // wait/notify as well which are delegated to the underlying Monitor.
256 // It also disallows null.
257 class MonitorLocker: public MutexLockerImpl {
258 Mutex::SafepointCheckFlag _flag;
259
260 protected:
261 Monitor* as_monitor() const {
262 return static_cast<Monitor*>(_mutex);
263 }
264
265 public:
266 MonitorLocker(Monitor* monitor, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
267 MutexLockerImpl(monitor, flag), _flag(flag) {
268 // Superclass constructor did locking
269 assert(monitor != nullptr, "null monitor not allowed");
270 }
271
272 MonitorLocker(Thread* thread, Monitor* monitor, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
273 MutexLockerImpl(thread, monitor, flag), _flag(flag) {
274 // Superclass constructor did locking
275 assert(monitor != nullptr, "null monitor not allowed");
276 }
277
278 bool wait(int64_t timeout = 0) {
279 return _flag == Mutex::_safepoint_check_flag ?
280 as_monitor()->wait(timeout) : as_monitor()->wait_without_safepoint_check(timeout);
281 }
282
283 void notify_all() {
284 as_monitor()->notify_all();
285 }
286
287 void notify() {
288 as_monitor()->notify();
289 }
290 };
291
292
293 // A GCMutexLocker is usually initialized with a mutex that is
294 // automatically acquired in order to do GC. The function that
295 // synchronizes using a GCMutexLocker may be called both during and between
296 // GC's. Thus, it must acquire the mutex if GC is not in progress, but not
297 // if GC is in progress (since the mutex is already held on its behalf.)
298
299 class GCMutexLocker: public StackObj {
300 private:
301 Mutex* _mutex;
302 bool _locked;
303 public:
304 GCMutexLocker(Mutex* mutex);
305 ~GCMutexLocker() { if (_locked) _mutex->unlock(); }
306 };
307
308 // A MutexUnlocker temporarily exits a previously
309 // entered mutex for the scope which contains the unlocker.
310
311 class MutexUnlocker: StackObj {
312 private:
313 Mutex* _mutex;
314 bool _no_safepoint_check;
315
316 public:
317 MutexUnlocker(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
318 _mutex(mutex),
319 _no_safepoint_check(flag == Mutex::_no_safepoint_check_flag) {
320 _mutex->unlock();
321 }
322
323 ~MutexUnlocker() {
324 if (_no_safepoint_check) {
325 _mutex->lock_without_safepoint_check();
326 } else {
327 _mutex->lock();
328 }
329 }
330 };
331
332 // Instance of a RecursiveLock that may be held through Java heap allocation, which may include calls to Java,
333 // and JNI event notification for resource exhaustion for metaspace or heap.
334 extern RecursiveMutex* MultiArray_lock;
335
336 // RAII locker for a RecursiveMutex. See comments in mutex.hpp for more information.
337 class RecursiveLocker {
338 RecursiveMutex* _lock;
339 Thread* _thread;
340 public:
341 RecursiveLocker(RecursiveMutex* lock, Thread* current) : _lock(lock), _thread(current) {
342 _lock->lock(_thread);
343 }
344 ~RecursiveLocker() {
345 _lock->unlock(_thread);
346 }
347 };
348
349 #endif // SHARE_RUNTIME_MUTEXLOCKER_HPP