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