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,
 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
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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*   ParGCRareEvent_lock;             // Synchronizes various (rare) parallel GC ops.
 98 extern Mutex*   Compile_lock;                    // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
 99 extern Monitor* MethodCompileQueue_lock;         // a lock held when method compilations are enqueued, dequeued
100 extern Monitor* CompileThread_lock;              // a lock held by compile threads during compilation system initialization
101 extern Monitor* Compilation_lock;                // a lock used to pause compilation
102 extern Mutex*   CompileTaskAlloc_lock;           // a lock held when CompileTasks are allocated
103 extern Mutex*   CompileStatistics_lock;          // a lock held when updating compilation statistics
104 extern Mutex*   DirectivesStack_lock;            // a lock held when mutating the dirstack and ref counting directives
105 extern Mutex*   MultiArray_lock;                 // a lock used to guard allocation of multi-dim arrays
106 extern Monitor* Terminator_lock;                 // a lock used to guard termination of the vm
107 extern Monitor* BeforeExit_lock;                 // a lock used to guard cleanups and shutdown hooks
108 extern Monitor* Notify_lock;                     // a lock used to synchronize the start-up of the vm
109 extern Mutex*   ProfilePrint_lock;               // a lock used to serialize the printing of profiles
110 extern Mutex*   ExceptionCache_lock;             // a lock used to synchronize exception cache updates
111 extern Mutex*   OsrList_lock;                    // a lock used to serialize access to OSR queues
112 
113 #ifndef PRODUCT
114 extern Mutex*   FullGCALot_lock;                 // a lock to make FullGCALot MT safe
115 #endif // PRODUCT
116 extern Mutex*   Debug1_lock;                     // A bunch of pre-allocated locks that can be used for tracing
117 extern Mutex*   Debug2_lock;                     // down synchronization related bugs!
118 extern Mutex*   Debug3_lock;
119 
120 extern Mutex*   RawMonitor_lock;
121 extern Mutex*   PerfDataMemAlloc_lock;           // a lock on the allocator for PerfData memory for performance data
122 extern Mutex*   PerfDataManager_lock;            // a long on access to PerfDataManager resources
123 extern Mutex*   ParkerFreeList_lock;
124 extern Mutex*   OopMapCacheAlloc_lock;           // protects allocation of oop_map caches
125 
126 extern Mutex*   FreeList_lock;                   // protects the free region list during safepoints
127 extern Mutex*   OldSets_lock;                    // protects the old region sets
128 extern Monitor* RootRegionScan_lock;             // used to notify that the CM threads have finished scanning the IM snapshot regions
129 
130 extern Mutex*   Management_lock;                 // a lock used to serialize JVM management
131 extern Monitor* Service_lock;                    // a lock used for service thread operation
132 extern Monitor* PeriodicTask_lock;               // protects the periodic task structure
133 extern Monitor* RedefineClasses_lock;            // locks classes from parallel redefinition
134 extern Mutex*   ThreadHeapSampler_lock;          // protects the static data for initialization.
135 
136 #if INCLUDE_JFR
137 extern Mutex*   JfrStacktrace_lock;              // used to guard access to the JFR stacktrace table
138 extern Monitor* JfrMsg_lock;                     // protects JFR messaging
139 extern Mutex*   JfrBuffer_lock;                  // protects JFR buffer operations
140 extern Mutex*   JfrStream_lock;                  // protects JFR stream access
141 #endif
142 
143 #ifndef SUPPORTS_NATIVE_CX8
144 extern Mutex*   UnsafeJlong_lock;                // provides Unsafe atomic updates to jlongs on platforms that don't support cx8
145 #endif
146 
147 extern Mutex*   MetaspaceExpand_lock;            // protects Metaspace virtualspace and chunk expansions
148 extern Mutex*   ClassLoaderDataGraph_lock;       // protects CLDG list, needed for concurrent unloading
149 
150 
151 extern Monitor* CodeHeapStateAnalytics_lock;     // lock print functions against concurrent analyze functions.
152                                                  // Only used locally in PrintCodeCacheLayout processing.
153 
154 // A MutexLocker provides mutual exclusion with respect to a given mutex
155 // for the scope which contains the locker.  The lock is an OS lock, not
156 // an object lock, and the two do not interoperate.  Do not use Mutex-based
157 // locks to lock on Java objects, because they will not be respected if a
158 // that object is locked using the Java locking mechanism.
159 //
160 //                NOTE WELL!!
161 //
162 // See orderAccess.hpp.  We assume throughout the VM that MutexLocker's
163 // and friends constructors do a fence, a lock and an acquire *in that
164 // order*.  And that their destructors do a release and unlock, in *that*
165 // order.  If their implementations change such that these assumptions
166 // are violated, a whole lot of code will break.
167 
168 // Print all mutexes/monitors that are currently owned by a thread; called
169 // by fatal error handler.
170 void print_owned_locks_on_error(outputStream* st);
171 
172 char *lock_name(Mutex *mutex);
173 
174 class MutexLocker: StackObj {
175  private:
176   Monitor * _mutex;
177  public:
178   MutexLocker(Monitor * mutex) {
179     assert(mutex->rank() != Mutex::special,
180       "Special ranked mutex should only use MutexLockerEx");
181     _mutex = mutex;
182     _mutex->lock();
183   }
184 
185   // Overloaded constructor passing current thread
186   MutexLocker(Monitor * mutex, Thread *thread) {
187     assert(mutex->rank() != Mutex::special,
188       "Special ranked mutex should only use MutexLockerEx");
189     _mutex = mutex;
190     _mutex->lock(thread);
191   }
192 
193   ~MutexLocker() {
194     _mutex->unlock();
195   }
196 
197 };
198 
199 // for debugging: check that we're already owning this lock (or are at a safepoint)
200 #ifdef ASSERT
201 void assert_locked_or_safepoint(const Monitor * lock);
202 void assert_locked_or_safepoint_weak(const Monitor * lock);
203 void assert_lock_strong(const Monitor * lock);
204 #else
205 #define assert_locked_or_safepoint(lock)
206 #define assert_locked_or_safepoint_weak(lock)
207 #define assert_lock_strong(lock)
208 #endif
209 
210 // A MutexLockerEx behaves like a MutexLocker when its constructor is
211 // called with a Mutex.  Unlike a MutexLocker, its constructor can also be
212 // called with NULL, in which case the MutexLockerEx is a no-op.  There
213 // is also a corresponding MutexUnlockerEx.  We want to keep the
214 // basic MutexLocker as fast as possible.  MutexLockerEx can also lock
215 // without safepoint check.
216 
217 class MutexLockerEx: public StackObj {
218  private:
219   Monitor * _mutex;
220  public:
221   MutexLockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
222     _mutex = mutex;
223     if (_mutex != NULL) {
224       assert(mutex->rank() > Mutex::special || no_safepoint_check,
225         "Mutexes with rank special or lower should not do safepoint checks");
226       if (no_safepoint_check)
227         _mutex->lock_without_safepoint_check();
228       else
229         _mutex->lock();
230     }
231   }
232 
233   ~MutexLockerEx() {
234     if (_mutex != NULL) {
235       _mutex->unlock();
236     }
237   }
238 };
239 
240 // A MonitorLockerEx is like a MutexLockerEx above, except it takes
241 // a possibly null Monitor, and allows wait/notify as well which are
242 // delegated to the underlying Monitor.
243 
244 class MonitorLockerEx: public MutexLockerEx {
245  private:
246   Monitor * _monitor;
247  public:
248   MonitorLockerEx(Monitor* monitor,
249                   bool no_safepoint_check = !Mutex::_no_safepoint_check_flag):
250     MutexLockerEx(monitor, no_safepoint_check),
251     _monitor(monitor) {
252     // Superclass constructor did locking
253   }
254 
255   ~MonitorLockerEx() {
256     #ifdef ASSERT
257       if (_monitor != NULL) {
258         assert_lock_strong(_monitor);
259       }
260     #endif  // ASSERT
261     // Superclass destructor will do unlocking
262   }
263 
264   bool wait(bool no_safepoint_check = !Mutex::_no_safepoint_check_flag,
265             long timeout = 0,
266             bool as_suspend_equivalent = !Mutex::_as_suspend_equivalent_flag) {
267     if (_monitor != NULL) {
268       return _monitor->wait(no_safepoint_check, timeout, as_suspend_equivalent);
269     }
270     return false;
271   }
272 
273   bool notify_all() {
274     if (_monitor != NULL) {
275       return _monitor->notify_all();
276     }
277     return true;
278   }
279 
280   bool notify() {
281     if (_monitor != NULL) {
282       return _monitor->notify();
283     }
284     return true;
285   }
286 };
287 
288 
289 
290 // A GCMutexLocker is usually initialized with a mutex that is
291 // automatically acquired in order to do GC.  The function that
292 // synchronizes using a GCMutexLocker may be called both during and between
293 // GC's.  Thus, it must acquire the mutex if GC is not in progress, but not
294 // if GC is in progress (since the mutex is already held on its behalf.)
295 
296 class GCMutexLocker: public StackObj {
297 private:
298   Monitor * _mutex;
299   bool _locked;
300 public:
301   GCMutexLocker(Monitor * mutex);
302   ~GCMutexLocker() { if (_locked) _mutex->unlock(); }
303 };
304 
305 
306 
307 // A MutexUnlocker temporarily exits a previously
308 // entered mutex for the scope which contains the unlocker.
309 
310 class MutexUnlocker: StackObj {
311  private:
312   Monitor * _mutex;
313 
314  public:
315   MutexUnlocker(Monitor * mutex) {
316     _mutex = mutex;
317     _mutex->unlock();
318   }
319 
320   ~MutexUnlocker() {
321     _mutex->lock();
322   }
323 };
324 
325 // A MutexUnlockerEx temporarily exits a previously
326 // entered mutex for the scope which contains the unlocker.
327 
328 class MutexUnlockerEx: StackObj {
329  private:
330   Monitor * _mutex;
331   bool _no_safepoint_check;
332 
333  public:
334   MutexUnlockerEx(Monitor * mutex, bool no_safepoint_check = !Mutex::_no_safepoint_check_flag) {
335     _mutex = mutex;
336     _no_safepoint_check = no_safepoint_check;
337     _mutex->unlock();
338   }
339 
340   ~MutexUnlockerEx() {
341     if (_no_safepoint_check == Mutex::_no_safepoint_check_flag) {
342       _mutex->lock_without_safepoint_check();
343     } else {
344       _mutex->lock();
345     }
346   }
347 };
348 
349 #ifndef PRODUCT
350 //
351 // A special MutexLocker that allows:
352 //   - reentrant locking
353 //   - locking out of order
354 //
355 // Only to be used for verify code, where we can relax out dead-lock
356 // detection code a bit (unsafe, but probably ok). This code is NEVER to
357 // be included in a product version.
358 //
359 class VerifyMutexLocker: StackObj {
360  private:
361   Monitor * _mutex;
362   bool   _reentrant;
363  public:
364   VerifyMutexLocker(Monitor * mutex) {
365     _mutex     = mutex;
366     _reentrant = mutex->owned_by_self();
367     if (!_reentrant) {
368       // We temp. disable strict safepoint checking, while we require the lock
369       FlagSetting fs(StrictSafepointChecks, false);
370       _mutex->lock();
371     }
372   }
373 
374   ~VerifyMutexLocker() {
375     if (!_reentrant) {
376       _mutex->unlock();
377     }
378   }
379 };
380 
381 #endif
382 
383 #endif // SHARE_VM_RUNTIME_MUTEXLOCKER_HPP