1 /*
  2  * Copyright (c) 1997, 2021, 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.
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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*   CompiledMethod_lock;             // a lock used to guard a compiled method and OSR queues
 36 extern Monitor* SystemDictionary_lock;           // a lock on the system dictionary
 37 extern Mutex*   SharedDictionary_lock;           // a lock on the CDS shared dictionary
 38 extern Monitor* ClassInitError_lock;             // a lock on the class initialization error table
 39 extern Mutex*   Module_lock;                     // a lock on module and package related data structures
 40 extern Mutex*   CompiledIC_lock;                 // a lock used to guard compiled IC patching and access
 41 extern Mutex*   InlineCacheBuffer_lock;          // a lock used to guard the InlineCacheBuffer
 42 extern Mutex*   VMStatistic_lock;                // a lock used to guard statistics count increment
 43 extern Mutex*   JNIHandleBlockFreeList_lock;     // a lock on the JNI handle block free list
 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* JvmtiVTMT_lock;                  // a lock for Virtual Thread Mount Transition (VTMT) management
 50 extern Monitor* Heap_lock;                       // a lock on the heap
 51 extern Mutex*   ExpandHeap_lock;                 // a lock on expanding the heap
 52 extern Mutex*   AdapterHandlerLibrary_lock;      // a lock on the AdapterHandlerLibrary
 53 extern Mutex*   SignatureHandlerLibrary_lock;    // a lock on the SignatureHandlerLibrary
 54 extern Mutex*   VtableStubs_lock;                // a lock on the VtableStubs
 55 extern Mutex*   SymbolArena_lock;                // a lock on the symbol table arena
 56 extern Monitor* StringDedup_lock;                // a lock on the string deduplication facility
 57 extern Mutex*   StringDedupIntern_lock;          // a lock on StringTable notification of StringDedup
 58 extern Monitor* CodeCache_lock;                  // a lock on the CodeCache
 59 extern Monitor* CodeSweeper_lock;                // a lock used by the sweeper only for wait notify
 60 extern Mutex*   MethodData_lock;                 // a lock on installation of method data
 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*   G1DetachedRefinementStats_lock;  // Lock protecting detached refinement stats
 73 extern Mutex*   MarkStackFreeList_lock;          // Protects access to the global mark stack free list.
 74 extern Mutex*   MarkStackChunkList_lock;         // Protects access to the global mark stack chunk list.
 75 extern Mutex*   MonitoringSupport_lock;          // Protects updates to the serviceability memory pools.
 76 extern Mutex*   ParGCRareEvent_lock;             // Synchronizes various (rare) parallel GC ops.
 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 Mutex*   MultiArray_lock;                 // a lock used to guard allocation of multi-dim arrays
 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 extern Mutex*   NMethodSweeperStats_lock;        // a lock used to serialize access to sweeper statistics
 92 
 93 #ifndef PRODUCT
 94 extern Mutex*   FullGCALot_lock;                 // a lock to make FullGCALot MT safe
 95 #endif // PRODUCT
 96 
 97 extern Mutex*   RawMonitor_lock;
 98 extern Mutex*   PerfDataMemAlloc_lock;           // a lock on the allocator for PerfData memory for performance data
 99 extern Mutex*   PerfDataManager_lock;            // a long on access to PerfDataManager resources
100 extern Mutex*   OopMapCacheAlloc_lock;           // protects allocation of oop_map caches
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* Zip_lock;                        // synchronize initialization of zip library
115 extern Monitor* ThreadsSMRDelete_lock;           // Used by ThreadsSMRSupport to take pressure off the Threads_lock
116 extern Mutex*   ThreadIdTableCreate_lock;        // Used by ThreadIdTable to lazily create the thread id table
117 extern Mutex*   SharedDecoder_lock;              // serializes access to the decoder during normal (not error reporting) use
118 extern Mutex*   DCmdFactory_lock;                // serialize access to DCmdFactory information
119 #if INCLUDE_NMT
120 extern Mutex*   NMTQuery_lock;                   // serialize NMT Dcmd queries
121 #endif
122 #if INCLUDE_CDS
123 #if INCLUDE_JVMTI
124 extern Mutex*   CDSClassFileStream_lock;         // FileMapInfo::open_stream_for_jvmti
125 #endif
126 extern Mutex*   DumpTimeTable_lock;              // SystemDictionaryShared::find_or_allocate_info_for
127 extern Mutex*   CDSLambda_lock;                  // SystemDictionaryShared::get_shared_lambda_proxy_class
128 extern Mutex*   DumpRegion_lock;                 // Symbol::operator new(size_t sz, int len)
129 extern Mutex*   ClassListFile_lock;              // ClassListWriter()
130 extern Mutex*   UnregisteredClassesTable_lock;   // UnregisteredClassesTableTable
131 extern Mutex*   LambdaFormInvokers_lock;         // Protecting LambdaFormInvokers::_lambdaform_lines
132 #endif // INCLUDE_CDS
133 #if INCLUDE_JFR
134 extern Mutex*   JfrStacktrace_lock;              // used to guard access to the JFR stacktrace table
135 extern Monitor* JfrMsg_lock;                     // protects JFR messaging
136 extern Mutex*   JfrBuffer_lock;                  // protects JFR buffer operations
137 extern Monitor* JfrThreadSampler_lock;           // used to suspend/resume JFR thread sampler
138 #endif
139 
140 #ifndef SUPPORTS_NATIVE_CX8
141 extern Mutex*   UnsafeJlong_lock;                // provides Unsafe atomic updates to jlongs on platforms that don't support cx8
142 #endif
143 
144 extern Mutex*   Metaspace_lock;            // protects Metaspace virtualspace and chunk expansions
145 extern Mutex*   ClassLoaderDataGraph_lock;       // protects CLDG list, needed for concurrent unloading
146 
147 
148 extern Mutex*   CodeHeapStateAnalytics_lock;     // lock print functions against concurrent analyze functions.
149                                                  // Only used locally in PrintCodeCacheLayout processing.
150 
151 #if INCLUDE_JVMCI
152 extern Monitor* JVMCI_lock;                      // Monitor to control initialization of JVMCI
153 #endif
154 
155 extern Mutex*   Bootclasspath_lock;
156 
157 extern Mutex* tty_lock;                          // lock to synchronize output.
158 
159 // A MutexLocker provides mutual exclusion with respect to a given mutex
160 // for the scope which contains the locker.  The lock is an OS lock, not
161 // an object lock, and the two do not interoperate.  Do not use Mutex-based
162 // locks to lock on Java objects, because they will not be respected if a
163 // that object is locked using the Java locking mechanism.
164 //
165 //                NOTE WELL!!
166 //
167 // See orderAccess.hpp.  We assume throughout the VM that MutexLocker's
168 // and friends constructors do a fence, a lock and an acquire *in that
169 // order*.  And that their destructors do a release and unlock, in *that*
170 // order.  If their implementations change such that these assumptions
171 // are violated, a whole lot of code will break.
172 
173 // Print all mutexes/monitors that are currently owned by a thread; called
174 // by fatal error handler.
175 void print_owned_locks_on_error(outputStream* st);
176 
177 char *lock_name(Mutex *mutex);
178 
179 // for debugging: check that we're already owning this lock (or are at a safepoint / handshake)
180 #ifdef ASSERT
181 void assert_locked_or_safepoint(const Mutex* lock);
182 void assert_locked_or_safepoint_weak(const Mutex* lock);
183 void assert_lock_strong(const Mutex* lock);
184 void assert_locked_or_safepoint_or_handshake(const Mutex* lock, const JavaThread* thread);
185 #else
186 #define assert_locked_or_safepoint(lock)
187 #define assert_locked_or_safepoint_weak(lock)
188 #define assert_lock_strong(lock)
189 #define assert_locked_or_safepoint_or_handshake(lock, thread)
190 #endif
191 
192 class MutexLocker: public StackObj {
193  protected:
194   Mutex* _mutex;
195  public:
196   MutexLocker(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 != NULL) {
200       if (no_safepoint_check) {
201         _mutex->lock_without_safepoint_check();
202       } else {
203         _mutex->lock();
204       }
205     }
206   }
207 
208   MutexLocker(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 != NULL) {
212       if (no_safepoint_check) {
213         _mutex->lock_without_safepoint_check(thread);
214       } else {
215         _mutex->lock(thread);
216       }
217     }
218   }
219 
220   ~MutexLocker() {
221     if (_mutex != NULL) {
222       assert_lock_strong(_mutex);
223       _mutex->unlock();
224     }
225   }
226 };
227 
228 // A MonitorLocker is like a MutexLocker above, except it allows
229 // wait/notify as well which are delegated to the underlying Monitor.
230 // It also disallows NULL.
231 
232 class MonitorLocker: public MutexLocker {
233   Mutex::SafepointCheckFlag _flag;
234 
235  protected:
236   Monitor* as_monitor() const {
237     return static_cast<Monitor*>(_mutex);
238   }
239 
240  public:
241   MonitorLocker(Monitor* monitor, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
242     MutexLocker(monitor, flag), _flag(flag) {
243     // Superclass constructor did locking
244     assert(monitor != NULL, "NULL monitor not allowed");
245   }
246 
247   MonitorLocker(Thread* thread, Monitor* monitor, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
248     MutexLocker(thread, monitor, flag), _flag(flag) {
249     // Superclass constructor did locking
250     assert(monitor != NULL, "NULL monitor not allowed");
251   }
252 
253   bool wait(int64_t timeout = 0) {
254     return _flag == Mutex::_safepoint_check_flag ?
255       as_monitor()->wait(timeout) : as_monitor()->wait_without_safepoint_check(timeout);
256   }
257 
258   void notify_all() {
259     as_monitor()->notify_all();
260   }
261 
262   void notify() {
263     as_monitor()->notify();
264   }
265 };
266 
267 
268 // A GCMutexLocker is usually initialized with a mutex that is
269 // automatically acquired in order to do GC.  The function that
270 // synchronizes using a GCMutexLocker may be called both during and between
271 // GC's.  Thus, it must acquire the mutex if GC is not in progress, but not
272 // if GC is in progress (since the mutex is already held on its behalf.)
273 
274 class GCMutexLocker: public StackObj {
275 private:
276   Mutex* _mutex;
277   bool _locked;
278 public:
279   GCMutexLocker(Mutex* mutex);
280   ~GCMutexLocker() { if (_locked) _mutex->unlock(); }
281 };
282 
283 // A MutexUnlocker temporarily exits a previously
284 // entered mutex for the scope which contains the unlocker.
285 
286 class MutexUnlocker: StackObj {
287  private:
288   Mutex* _mutex;
289   bool _no_safepoint_check;
290 
291  public:
292   MutexUnlocker(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
293     _mutex(mutex),
294     _no_safepoint_check(flag == Mutex::_no_safepoint_check_flag) {
295     _mutex->unlock();
296   }
297 
298   ~MutexUnlocker() {
299     if (_no_safepoint_check) {
300       _mutex->lock_without_safepoint_check();
301     } else {
302       _mutex->lock();
303     }
304   }
305 };
306 
307 #endif // SHARE_RUNTIME_MUTEXLOCKER_HPP