1 /*
  2  * Copyright (c) 1997, 2018, 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,
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 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
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 24 
 25 #ifndef SHARE_VM_RUNTIME_MUTEXLOCKER_HPP
 26 #define SHARE_VM_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 Monitor* SystemDictionary_lock;           // a lock on the system dictionary
 36 extern Mutex*   SharedDictionary_lock;           // a lock on the CDS shared dictionary
 37 extern Mutex*   Module_lock;                     // a lock on module and package related data structures
 38 extern Mutex*   CompiledIC_lock;                 // a lock used to guard compiled IC patching and access
 39 extern Mutex*   InlineCacheBuffer_lock;          // a lock used to guard the InlineCacheBuffer
 40 extern Mutex*   VMStatistic_lock;                // a lock used to guard statistics count increment
 41 extern Mutex*   JNIGlobalAlloc_lock;             // JNI global storage allocate list lock
 42 extern Mutex*   JNIGlobalActive_lock;            // JNI global storage active list lock
 43 extern Mutex*   JNIWeakAlloc_lock;               // JNI weak storage allocate list lock
 44 extern Mutex*   JNIWeakActive_lock;              // JNI weak storage active list lock
 45 extern Mutex*   StringTableWeakAlloc_lock;       // StringTable weak storage allocate list lock
 46 extern Mutex*   StringTableWeakActive_lock;      // STringTable weak storage active list lock
 47 extern Mutex*   JNIHandleBlockFreeList_lock;     // a lock on the JNI handle block free list
 48 extern Mutex*   VMWeakAlloc_lock;                // VM Weak Handles storage allocate list lock
 49 extern Mutex*   VMWeakActive_lock;               // VM Weak Handles storage active list lock
 50 extern Mutex*   ResolvedMethodTable_lock;        // a lock on the ResolvedMethodTable updates
 51 extern Mutex*   JmethodIdCreation_lock;          // a lock on creating JNI method identifiers
 52 extern Mutex*   JfieldIdCreation_lock;           // a lock on creating JNI static field identifiers
 53 extern Monitor* JNICritical_lock;                // a lock used while entering and exiting JNI critical regions, allows GC to sometimes get in
 54 extern Mutex*   JvmtiThreadState_lock;           // a lock on modification of JVMTI thread data
 55 extern Monitor* Heap_lock;                       // a lock on the heap
 56 extern Mutex*   ExpandHeap_lock;                 // a lock on expanding the heap
 57 extern Mutex*   AdapterHandlerLibrary_lock;      // a lock on the AdapterHandlerLibrary
 58 extern Mutex*   SignatureHandlerLibrary_lock;    // a lock on the SignatureHandlerLibrary
 59 extern Mutex*   VtableStubs_lock;                // a lock on the VtableStubs
 60 extern Mutex*   SymbolArena_lock;                // a lock on the symbol table arena
 61 extern Mutex*   StringTable_lock;                // a lock on the interned string table
 62 extern Monitor* StringDedupQueue_lock;           // a lock on the string deduplication queue
 63 extern Mutex*   StringDedupTable_lock;           // a lock on the string deduplication table
 64 extern Monitor* CodeCache_lock;                  // a lock on the CodeCache, rank is special, use MutexLockerEx
 65 extern Mutex*   MethodData_lock;                 // a lock on installation of method data
 66 extern Mutex*   TouchedMethodLog_lock;           // a lock on allocation of LogExecutedMethods info
 67 extern Mutex*   RetData_lock;                    // a lock on installation of RetData inside method data
 68 extern Mutex*   DerivedPointerTableGC_lock;      // a lock to protect the derived pointer table
 69 extern Monitor* CGCPhaseManager_lock;            // a lock to protect a concurrent GC's phase management
 70 extern Monitor* VMOperationQueue_lock;           // a lock on queue of vm_operations waiting to execute
 71 extern Monitor* VMOperationRequest_lock;         // a lock on Threads waiting for a vm_operation to terminate
 72 extern Monitor* Safepoint_lock;                  // a lock used by the safepoint abstraction
 73 extern Monitor* Threads_lock;                    // a lock on the Threads table of active Java threads
 74                                                  // (also used by Safepoints too to block threads creation/destruction)
 75 extern Mutex*   NonJavaThreadsList_lock;         // a lock on the NonJavaThreads list
 76 extern Monitor* CGC_lock;                        // used for coordination between
 77                                                  // fore- & background GC threads.
 78 extern Monitor* STS_lock;                        // used for joining/leaving SuspendibleThreadSet.
 79 extern Monitor* FullGCCount_lock;                // in support of "concurrent" full gc
 80 extern Mutex*   SATB_Q_FL_lock;                  // Protects SATB Q
 81                                                  // buffer free list.
 82 extern Monitor* SATB_Q_CBL_mon;                  // Protects SATB Q
 83                                                  // completed buffer queue.
 84 extern Mutex*   Shared_SATB_Q_lock;              // Lock protecting SATB
 85                                                  // queue shared by
 86                                                  // non-Java threads.
 87 
 88 extern Mutex*   DirtyCardQ_FL_lock;              // Protects dirty card Q
 89                                                  // buffer free list.
 90 extern Monitor* DirtyCardQ_CBL_mon;              // Protects dirty card Q
 91                                                  // completed buffer queue.
 92 extern Mutex*   Shared_DirtyCardQ_lock;          // Lock protecting dirty card
 93                                                  // queue shared by
 94                                                  // non-Java threads.
 95 extern Mutex*   MarkStackFreeList_lock;          // Protects access to the global mark stack free list.
 96 extern Mutex*   MarkStackChunkList_lock;         // Protects access to the global mark stack chunk list.
 97 extern Mutex*   MonitoringSupport_lock;          // Protects updates to the serviceability memory pools.
 98 extern Mutex*   ParGCRareEvent_lock;             // Synchronizes various (rare) parallel GC ops.
 99 extern Mutex*   Compile_lock;                    // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
100 extern Monitor* MethodCompileQueue_lock;         // a lock held when method compilations are enqueued, dequeued
101 extern Monitor* CompileThread_lock;              // a lock held by compile threads during compilation system initialization
102 extern Monitor* Compilation_lock;                // a lock used to pause compilation
103 extern Mutex*   CompileTaskAlloc_lock;           // a lock held when CompileTasks are allocated
104 extern Mutex*   CompileStatistics_lock;          // a lock held when updating compilation statistics
105 extern Mutex*   DirectivesStack_lock;            // a lock held when mutating the dirstack and ref counting directives
106 extern Mutex*   MultiArray_lock;                 // a lock used to guard allocation of multi-dim arrays
107 extern Monitor* Terminator_lock;                 // a lock used to guard termination of the vm
108 extern Monitor* BeforeExit_lock;                 // a lock used to guard cleanups and shutdown hooks
109 extern Monitor* Notify_lock;                     // a lock used to synchronize the start-up of the vm
110 extern Mutex*   ProfilePrint_lock;               // a lock used to serialize the printing of profiles
111 extern Mutex*   ExceptionCache_lock;             // a lock used to synchronize exception cache updates
112 extern Mutex*   OsrList_lock;                    // a lock used to serialize access to OSR queues
113 
114 #ifndef PRODUCT
115 extern Mutex*   FullGCALot_lock;                 // a lock to make FullGCALot MT safe
116 #endif // PRODUCT
117 extern Mutex*   Debug1_lock;                     // A bunch of pre-allocated locks that can be used for tracing
118 extern Mutex*   Debug2_lock;                     // down synchronization related bugs!
119 extern Mutex*   Debug3_lock;
120 
121 extern Mutex*   RawMonitor_lock;
122 extern Mutex*   PerfDataMemAlloc_lock;           // a lock on the allocator for PerfData memory for performance data
123 extern Mutex*   PerfDataManager_lock;            // a long on access to PerfDataManager resources
124 extern Mutex*   ParkerFreeList_lock;
125 extern Mutex*   OopMapCacheAlloc_lock;           // protects allocation of oop_map caches
126 
127 extern Mutex*   FreeList_lock;                   // protects the free region list during safepoints
128 extern Mutex*   OldSets_lock;                    // protects the old region sets
129 extern Monitor* RootRegionScan_lock;             // used to notify that the CM threads have finished scanning the IM snapshot regions
130 
131 extern Mutex*   Management_lock;                 // a lock used to serialize JVM management
132 extern Monitor* Service_lock;                    // a lock used for service thread operation
133 extern Monitor* PeriodicTask_lock;               // protects the periodic task structure
134 extern Monitor* RedefineClasses_lock;            // locks classes from parallel redefinition
135 extern Mutex*   ThreadHeapSampler_lock;          // protects the static data for initialization.
136 
137 #if INCLUDE_JFR
138 extern Mutex*   JfrStacktrace_lock;              // used to guard access to the JFR stacktrace table
139 extern Monitor* JfrMsg_lock;                     // protects JFR messaging
140 extern Mutex*   JfrBuffer_lock;                  // protects JFR buffer operations
141 extern Mutex*   JfrStream_lock;                  // protects JFR stream access
142 #endif
143 
144 #ifndef SUPPORTS_NATIVE_CX8
145 extern Mutex*   UnsafeJlong_lock;                // provides Unsafe atomic updates to jlongs on platforms that don't support cx8
146 #endif
147 
148 extern Mutex*   MetaspaceExpand_lock;            // protects Metaspace virtualspace and chunk expansions
149 extern Mutex*   ClassLoaderDataGraph_lock;       // protects CLDG list, needed for concurrent unloading
150 
151 
152 extern Monitor* CodeHeapStateAnalytics_lock;     // lock print functions against concurrent analyze functions.
153                                                  // Only used locally in PrintCodeCacheLayout processing.
154 
155 // A MutexLocker provides mutual exclusion with respect to a given mutex
156 // for the scope which contains the locker.  The lock is an OS lock, not
157 // an object lock, and the two do not interoperate.  Do not use Mutex-based
158 // locks to lock on Java objects, because they will not be respected if a
159 // that object is locked using the Java locking mechanism.
160 //
161 //                NOTE WELL!!
162 //
163 // See orderAccess.hpp.  We assume throughout the VM that MutexLocker's
164 // and friends constructors do a fence, a lock and an acquire *in that
165 // order*.  And that their destructors do a release and unlock, in *that*
166 // order.  If their implementations change such that these assumptions
167 // are violated, a whole lot of code will break.
168 
169 // Print all mutexes/monitors that are currently owned by a thread; called
170 // by fatal error handler.
171 void print_owned_locks_on_error(outputStream* st);
172 
173 char *lock_name(Mutex *mutex);
174 
175 class MutexLocker: StackObj {
176  private:
177   Monitor * _mutex;
178  public:
179   MutexLocker(Monitor * mutex) {
180     assert(mutex->rank() != Mutex::special,
181       "Special ranked mutex should only use MutexLockerEx");
182     _mutex = mutex;
183     _mutex->lock();
184   }
185 
186   // Overloaded constructor passing current thread
187   MutexLocker(Monitor * mutex, Thread *thread) {
188     assert(mutex->rank() != Mutex::special,
189       "Special ranked mutex should only use MutexLockerEx");
190     _mutex = mutex;
191     _mutex->lock(thread);
192   }
193 
194   ~MutexLocker() {
195     _mutex->unlock();
196   }
197 
198 };
199 
200 // for debugging: check that we're already owning this lock (or are at a safepoint)
201 #ifdef ASSERT
202 void assert_locked_or_safepoint(const Monitor * lock);
203 void assert_lock_strong(const Monitor * lock);
204 #else
205 #define assert_locked_or_safepoint(lock)
206 #define assert_lock_strong(lock)
207 #endif
208 
209 // A MutexLockerEx behaves like a MutexLocker when its constructor is
210 // called with a Mutex.  Unlike a MutexLocker, its constructor can also be
211 // called with NULL, in which case the MutexLockerEx is a no-op.  There
212 // is also a corresponding MutexUnlockerEx.  We want to keep the
213 // basic MutexLocker as fast as possible.  MutexLockerEx can also lock
214 // without safepoint check.
215 
216 class MutexLockerEx: public StackObj {
217  private:
218   Monitor * _mutex;
219  public:
220   MutexLockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
221     _mutex = mutex;
222     if (_mutex != NULL) {
223       assert(mutex->rank() > Mutex::special || no_safepoint_check,
224         "Mutexes with rank special or lower should not do safepoint checks");
225       if (no_safepoint_check)
226         _mutex->lock_without_safepoint_check();
227       else
228         _mutex->lock();
229     }
230   }
231 
232   ~MutexLockerEx() {
233     if (_mutex != NULL) {
234       _mutex->unlock();
235     }
236   }
237 };
238 
239 // A MonitorLockerEx is like a MutexLockerEx above, except it takes
240 // a possibly null Monitor, and allows wait/notify as well which are
241 // delegated to the underlying Monitor.
242 
243 class MonitorLockerEx: public MutexLockerEx {
244  private:
245   Monitor * _monitor;
246  public:
247   MonitorLockerEx(Monitor* monitor,
248                   bool no_safepoint_check = !Mutex::_no_safepoint_check_flag):
249     MutexLockerEx(monitor, no_safepoint_check),
250     _monitor(monitor) {
251     // Superclass constructor did locking
252   }
253 
254   ~MonitorLockerEx() {
255     #ifdef ASSERT
256       if (_monitor != NULL) {
257         assert_lock_strong(_monitor);
258       }
259     #endif  // ASSERT
260     // Superclass destructor will do unlocking
261   }
262 
263   bool wait(bool no_safepoint_check = !Mutex::_no_safepoint_check_flag,
264             long timeout = 0,
265             bool as_suspend_equivalent = !Mutex::_as_suspend_equivalent_flag) {
266     if (_monitor != NULL) {
267       return _monitor->wait(no_safepoint_check, timeout, as_suspend_equivalent);
268     }
269     return false;
270   }
271 
272   bool notify_all() {
273     if (_monitor != NULL) {
274       return _monitor->notify_all();
275     }
276     return true;
277   }
278 
279   bool notify() {
280     if (_monitor != NULL) {
281       return _monitor->notify();
282     }
283     return true;
284   }
285 };
286 
287 
288 
289 // A GCMutexLocker is usually initialized with a mutex that is
290 // automatically acquired in order to do GC.  The function that
291 // synchronizes using a GCMutexLocker may be called both during and between
292 // GC's.  Thus, it must acquire the mutex if GC is not in progress, but not
293 // if GC is in progress (since the mutex is already held on its behalf.)
294 
295 class GCMutexLocker: public StackObj {
296 private:
297   Monitor * _mutex;
298   bool _locked;
299 public:
300   GCMutexLocker(Monitor * mutex);
301   ~GCMutexLocker() { if (_locked) _mutex->unlock(); }
302 };
303 
304 
305 
306 // A MutexUnlocker temporarily exits a previously
307 // entered mutex for the scope which contains the unlocker.
308 
309 class MutexUnlocker: StackObj {
310  private:
311   Monitor * _mutex;
312 
313  public:
314   MutexUnlocker(Monitor * mutex) {
315     _mutex = mutex;
316     _mutex->unlock();
317   }
318 
319   ~MutexUnlocker() {
320     _mutex->lock();
321   }
322 };
323 
324 // A MutexUnlockerEx temporarily exits a previously
325 // entered mutex for the scope which contains the unlocker.
326 
327 class MutexUnlockerEx: StackObj {
328  private:
329   Monitor * _mutex;
330   bool _no_safepoint_check;
331 
332  public:
333   MutexUnlockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
334     _mutex = mutex;
335     _no_safepoint_check = no_safepoint_check;
336     _mutex->unlock();
337   }
338 
339   ~MutexUnlockerEx() {
340     if (_no_safepoint_check == Mutex::_no_safepoint_check_flag) {
341       _mutex->lock_without_safepoint_check();
342     } else {
343       _mutex->lock();
344     }
345   }
346 };
347 
348 #ifndef PRODUCT
349 //
350 // A special MutexLocker that allows:
351 //   - reentrant locking
352 //   - locking out of order
353 //
354 // Only to be used for verify code, where we can relax out dead-lock
355 // detection code a bit (unsafe, but probably ok). This code is NEVER to
356 // be included in a product version.
357 //
358 class VerifyMutexLocker: StackObj {
359  private:
360   Monitor * _mutex;
361   bool   _reentrant;
362  public:
363   VerifyMutexLocker(Monitor * mutex) {
364     _mutex     = mutex;
365     _reentrant = mutex->owned_by_self();
366     if (!_reentrant) {
367       // We temp. disable strict safepoint checking, while we require the lock
368       FlagSetting fs(StrictSafepointChecks, false);
369       _mutex->lock();
370     }
371   }
372 
373   ~VerifyMutexLocker() {
374     if (!_reentrant) {
375       _mutex->unlock();
376     }
377   }
378 };
379 
380 #endif
381 
382 #endif // SHARE_VM_RUNTIME_MUTEXLOCKER_HPP