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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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 // Mutexes used in the VM.
33
34 extern Mutex* Patching_lock; // a lock used to guard code patching of compiled code
35 extern Mutex* NMethodState_lock; // a lock used to guard a compiled method state
36 extern Monitor* SystemDictionary_lock; // a lock on the system dictionary
37 extern Mutex* InvokeMethodTypeTable_lock;
38 extern Monitor* InvokeMethodIntrinsicTable_lock;
39 extern Mutex* SharedDictionary_lock; // a lock on the CDS shared dictionary
40 extern Monitor* ClassInitError_lock; // a lock on the class initialization error table
41 extern Mutex* Module_lock; // a lock on module and package related data structures
42 extern Mutex* CompiledIC_lock; // a lock used to guard compiled IC patching and access
43 extern Mutex* InlineCacheBuffer_lock; // a lock used to guard the InlineCacheBuffer
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* Threads_lock; // a lock on the Threads table of active Java threads
66 // (also used by Safepoints too to block threads creation/destruction)
67 extern Mutex* NonJavaThreadsList_lock; // a lock on the NonJavaThreads list
68 extern Mutex* NonJavaThreadsListSync_lock; // a lock for NonJavaThreads list synchronization
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* G1OldGCCount_lock; // in support of "concurrent" full gc
73 extern Mutex* G1RareEvent_lock; // Synchronizes (rare) parallel GC operations.
74 extern Mutex* G1DetachedRefinementStats_lock; // Lock protecting detached refinement stats
75 extern Mutex* MarkStackFreeList_lock; // Protects access to the global mark stack free list.
76 extern Mutex* MarkStackChunkList_lock; // Protects access to the global mark stack chunk list.
77 extern Mutex* MonitoringSupport_lock; // Protects updates to the serviceability memory pools and allocated memory high water mark.
78 extern Monitor* ConcurrentGCBreakpoints_lock; // Protects concurrent GC breakpoint management
79 extern Mutex* Compile_lock; // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
80 extern Monitor* MethodCompileQueue_lock; // a lock held when method compilations are enqueued, dequeued
81 extern Monitor* CompileThread_lock; // a lock held by compile threads during compilation system initialization
82 extern Monitor* Compilation_lock; // a lock used to pause compilation
83 extern Mutex* CompileTaskAlloc_lock; // a lock held when CompileTasks are allocated
84 extern Mutex* CompileStatistics_lock; // a lock held when updating compilation statistics
85 extern Mutex* DirectivesStack_lock; // a lock held when mutating the dirstack and ref counting directives
86 extern Monitor* Terminator_lock; // a lock used to guard termination of the vm
87 extern Monitor* InitCompleted_lock; // a lock used to signal threads waiting on init completed
88 extern Monitor* BeforeExit_lock; // a lock used to guard cleanups and shutdown hooks
89 extern Monitor* Notify_lock; // a lock used to synchronize the start-up of the vm
90 extern Mutex* ExceptionCache_lock; // a lock used to synchronize exception cache updates
91
92 #ifndef PRODUCT
93 extern Mutex* FullGCALot_lock; // a lock to make FullGCALot MT safe
94 #endif // PRODUCT
95
96 extern Mutex* RawMonitor_lock;
97 extern Mutex* PerfDataMemAlloc_lock; // a lock on the allocator for PerfData memory for performance data
98 extern Mutex* PerfDataManager_lock; // a long on access to PerfDataManager resources
99
100 extern Mutex* FreeList_lock; // protects the free region list during safepoints
101 extern Mutex* OldSets_lock; // protects the old region sets
102 extern Mutex* Uncommit_lock; // protects the uncommit list when not at safepoints
103 extern Monitor* RootRegionScan_lock; // used to notify that the CM threads have finished scanning the IM snapshot regions
104
105 extern Mutex* Management_lock; // a lock used to serialize JVM management
106 extern Monitor* MonitorDeflation_lock; // a lock used for monitor deflation thread operation
107 extern Monitor* Service_lock; // a lock used for service thread operation
108 extern Monitor* Notification_lock; // a lock used for notification thread operation
109 extern Monitor* PeriodicTask_lock; // protects the periodic task structure
110 extern Monitor* RedefineClasses_lock; // locks classes from parallel redefinition
111 extern Mutex* Verify_lock; // synchronize initialization of verify library
112 extern Monitor* ThreadsSMRDelete_lock; // Used by ThreadsSMRSupport to take pressure off the Threads_lock
113 extern Mutex* ThreadIdTableCreate_lock; // Used by ThreadIdTable to lazily create the thread id table
114 extern Mutex* SharedDecoder_lock; // serializes access to the decoder during normal (not error reporting) use
115 extern Mutex* DCmdFactory_lock; // serialize access to DCmdFactory information
116 extern Mutex* NMTQuery_lock; // serialize NMT Dcmd queries
117 extern Mutex* NMTCompilationCostHistory_lock; // guards NMT compilation cost history
118 #if INCLUDE_CDS
119 #if INCLUDE_JVMTI
120 extern Mutex* CDSClassFileStream_lock; // FileMapInfo::open_stream_for_jvmti
121 #endif
122 extern Mutex* DumpTimeTable_lock; // SystemDictionaryShared::_dumptime_table
123 extern Mutex* CDSLambda_lock; // SystemDictionaryShared::get_shared_lambda_proxy_class
124 extern Mutex* DumpRegion_lock; // Symbol::operator new(size_t sz, int len)
125 extern Mutex* ClassListFile_lock; // ClassListWriter()
126 extern Mutex* UnregisteredClassesTable_lock; // UnregisteredClassesTableTable
127 extern Mutex* LambdaFormInvokers_lock; // Protecting LambdaFormInvokers::_lambdaform_lines
128 extern Mutex* ScratchObjects_lock; // Protecting _scratch_xxx_table in heapShared.cpp
129 #endif // INCLUDE_CDS
130 #if INCLUDE_JFR
131 extern Mutex* JfrStacktrace_lock; // used to guard access to the JFR stacktrace table
132 extern Monitor* JfrMsg_lock; // protects JFR messaging
133 extern Mutex* JfrBuffer_lock; // protects JFR buffer operations
134 extern Monitor* JfrThreadSampler_lock; // used to suspend/resume JFR thread sampler
135 #endif
136
137 extern Mutex* Metaspace_lock; // protects Metaspace virtualspace and chunk expansions
138 extern Monitor* MetaspaceCritical_lock; // synchronizes failed metaspace allocations that risk throwing metaspace OOM
139 extern Mutex* ClassLoaderDataGraph_lock; // protects CLDG list, needed for concurrent unloading
140
141
142 extern Mutex* CodeHeapStateAnalytics_lock; // lock print functions against concurrent analyze functions.
143 // Only used locally in PrintCodeCacheLayout processing.
144
145 extern Monitor* ContinuationRelativize_lock;
146
147 #if INCLUDE_JVMCI
148 extern Monitor* JVMCI_lock; // protects global JVMCI critical sections
149 extern Monitor* JVMCIRuntime_lock; // protects critical sections for a specific JVMCIRuntime object
150 #endif
151
152 extern Mutex* Bootclasspath_lock;
153
154 extern Mutex* tty_lock; // lock to synchronize output.
155
156 // A MutexLocker provides mutual exclusion with respect to a given mutex
157 // for the scope which contains the locker. The lock is an OS lock, not
158 // an object lock, and the two do not interoperate. Do not use Mutex-based
159 // locks to lock on Java objects, because they will not be respected if a
160 // that object is locked using the Java locking mechanism.
161 //
162 // NOTE WELL!!
163 //
164 // See orderAccess.hpp. We assume throughout the VM that MutexLocker's
165 // and friends constructors do a fence, a lock and an acquire *in that
166 // order*. And that their destructors do a release and unlock, in *that*
167 // order. If their implementations change such that these assumptions
168 // are violated, a whole lot of code will break.
169
170 // Print all mutexes/monitors that are currently owned by a thread; called
171 // by fatal error handler.
172 void print_owned_locks_on_error(outputStream* st);
173 void print_lock_ranks(outputStream* st);
174
175 // for debugging: check that we're already owning this lock (or are at a safepoint / handshake)
176 #ifdef ASSERT
177 void assert_locked_or_safepoint(const Mutex* lock);
178 void assert_lock_strong(const Mutex* lock);
179 #else
180 #define assert_locked_or_safepoint(lock)
181 #define assert_lock_strong(lock)
182 #endif
183
184 // Internal implementation. Skips on null Mutex.
185 // Subclasses enforce stronger invariants.
186 class MutexLockerImpl: public StackObj {
187 protected:
188 Mutex* _mutex;
189
190 MutexLockerImpl(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
191 _mutex(mutex) {
192 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
193 if (_mutex != nullptr) {
194 if (no_safepoint_check) {
195 _mutex->lock_without_safepoint_check();
196 } else {
197 _mutex->lock();
198 }
199 }
200 }
201
202 MutexLockerImpl(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
203 _mutex(mutex) {
204 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
205 if (_mutex != nullptr) {
206 if (no_safepoint_check) {
207 _mutex->lock_without_safepoint_check(thread);
208 } else {
209 _mutex->lock(thread);
210 }
211 }
212 }
213
214 ~MutexLockerImpl() {
215 if (_mutex != nullptr) {
216 assert_lock_strong(_mutex);
217 _mutex->unlock();
218 }
219 }
220
221 public:
222 static void post_initialize();
223 };
224
225 // Simplest mutex locker.
226 // Does not allow null mutexes.
227 class MutexLocker: public MutexLockerImpl {
228 public:
229 MutexLocker(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
230 MutexLockerImpl(mutex, flag) {
231 assert(mutex != nullptr, "null mutex not allowed");
232 }
233
234 MutexLocker(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
235 MutexLockerImpl(thread, mutex, flag) {
236 assert(mutex != nullptr, "null mutex not allowed");
237 }
238 };
239
240 // Conditional mutex locker.
241 // Like MutexLocker above, but only locks when condition is true.
242 class ConditionalMutexLocker: public MutexLockerImpl {
243 public:
244 ConditionalMutexLocker(Mutex* mutex, bool condition, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
245 MutexLockerImpl(condition ? mutex : nullptr, flag) {
246 assert(!condition || mutex != nullptr, "null mutex not allowed when locking");
247 }
248
249 ConditionalMutexLocker(Thread* thread, Mutex* mutex, bool condition, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
250 MutexLockerImpl(thread, condition ? mutex : nullptr, flag) {
251 assert(!condition || mutex != nullptr, "null mutex not allowed when locking");
252 }
253 };
254
255 // A MonitorLocker is like a MutexLocker above, except it allows
256 // wait/notify as well which are delegated to the underlying Monitor.
257 // It also disallows null.
258 class MonitorLocker: public MutexLockerImpl {
259 Mutex::SafepointCheckFlag _flag;
260
261 protected:
262 Monitor* as_monitor() const {
263 return static_cast<Monitor*>(_mutex);
264 }
265
266 public:
267 MonitorLocker(Monitor* monitor, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
268 MutexLockerImpl(monitor, flag), _flag(flag) {
269 // Superclass constructor did locking
270 assert(monitor != nullptr, "null monitor not allowed");
271 }
272
273 MonitorLocker(Thread* thread, Monitor* monitor, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
274 MutexLockerImpl(thread, monitor, flag), _flag(flag) {
275 // Superclass constructor did locking
276 assert(monitor != nullptr, "null monitor not allowed");
277 }
278
279 bool wait(int64_t timeout = 0) {
280 return _flag == Mutex::_safepoint_check_flag ?
281 as_monitor()->wait(timeout) : as_monitor()->wait_without_safepoint_check(timeout);
282 }
283
284 void notify_all() {
285 as_monitor()->notify_all();
286 }
287
288 void notify() {
289 as_monitor()->notify();
290 }
291 };
292
293
294 // A GCMutexLocker is usually initialized with a mutex that is
295 // automatically acquired in order to do GC. The function that
296 // synchronizes using a GCMutexLocker may be called both during and between
297 // GC's. Thus, it must acquire the mutex if GC is not in progress, but not
298 // if GC is in progress (since the mutex is already held on its behalf.)
299
300 class GCMutexLocker: public StackObj {
301 private:
302 Mutex* _mutex;
303 bool _locked;
304 public:
305 GCMutexLocker(Mutex* mutex);
306 ~GCMutexLocker() { if (_locked) _mutex->unlock(); }
307 };
308
309 // A MutexUnlocker temporarily exits a previously
310 // entered mutex for the scope which contains the unlocker.
311
312 class MutexUnlocker: StackObj {
313 private:
314 Mutex* _mutex;
315 bool _no_safepoint_check;
316
317 public:
318 MutexUnlocker(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
319 _mutex(mutex),
320 _no_safepoint_check(flag == Mutex::_no_safepoint_check_flag) {
321 _mutex->unlock();
322 }
323
324 ~MutexUnlocker() {
325 if (_no_safepoint_check) {
326 _mutex->lock_without_safepoint_check();
327 } else {
328 _mutex->lock();
329 }
330 }
331 };
332
333 // Instance of a RecursiveLock that may be held through Java heap allocation, which may include calls to Java,
334 // and JNI event notification for resource exhaustion for metaspace or heap.
335 extern RecursiveMutex* MultiArray_lock;
336
337 // RAII locker for a RecursiveMutex. See comments in mutex.hpp for more information.
338 class RecursiveLocker {
339 RecursiveMutex* _lock;
340 Thread* _thread;
341 public:
342 RecursiveLocker(RecursiveMutex* lock, Thread* current) : _lock(lock), _thread(current) {
343 _lock->lock(_thread);
344 }
345 ~RecursiveLocker() {
346 _lock->unlock(_thread);
347 }
348 };
349
350 #endif // SHARE_RUNTIME_MUTEXLOCKER_HPP