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
 21  * questions.
 22  *
 23  */
 24 
 25 #include "precompiled.hpp"
 26 #include "runtime/mutexLocker.hpp"
 27 #include "runtime/os.inline.hpp"
 28 #include "runtime/safepoint.hpp"
 29 #include "runtime/thread.inline.hpp"
 30 #include "runtime/vmThread.hpp"
 31 
 32 // Mutexes used in the VM (see comment in mutexLocker.hpp):
 33 //
 34 // Note that the following pointers are effectively final -- after having been
 35 // set at JVM startup-time, they should never be subsequently mutated.
 36 // Instead of using pointers to malloc()ed monitors and mutexes we should consider
 37 // eliminating the indirection and using instances instead.
 38 // Consider using GCC's __read_mostly.
 39 
 40 Mutex*   Patching_lock                = NULL;
 41 Monitor* SystemDictionary_lock        = NULL;
 42 Mutex*   SharedDictionary_lock        = NULL;
 43 Mutex*   Module_lock                  = NULL;
 44 Mutex*   CompiledIC_lock              = NULL;
 45 Mutex*   InlineCacheBuffer_lock       = NULL;
 46 Mutex*   VMStatistic_lock             = NULL;
 47 Mutex*   JNIGlobalAlloc_lock          = NULL;
 48 Mutex*   JNIGlobalActive_lock         = NULL;
 49 Mutex*   JNIWeakAlloc_lock            = NULL;
 50 Mutex*   JNIWeakActive_lock           = NULL;
 51 Mutex*   StringTableWeakAlloc_lock    = NULL;
 52 Mutex*   StringTableWeakActive_lock   = NULL;
 53 Mutex*   JNIHandleBlockFreeList_lock  = NULL;
 54 Mutex*   VMWeakAlloc_lock             = NULL;
 55 Mutex*   VMWeakActive_lock            = NULL;
 56 Mutex*   ResolvedMethodTable_lock     = NULL;
 57 Mutex*   JmethodIdCreation_lock       = NULL;
 58 Mutex*   JfieldIdCreation_lock        = NULL;
 59 Monitor* JNICritical_lock             = NULL;
 60 Mutex*   JvmtiThreadState_lock        = NULL;
 61 Monitor* Heap_lock                    = NULL;
 62 Mutex*   ExpandHeap_lock              = NULL;
 63 Mutex*   AdapterHandlerLibrary_lock   = NULL;
 64 Mutex*   SignatureHandlerLibrary_lock = NULL;
 65 Mutex*   VtableStubs_lock             = NULL;
 66 Mutex*   SymbolArena_lock             = NULL;
 67 Mutex*   StringTable_lock             = NULL;
 68 Monitor* StringDedupQueue_lock        = NULL;
 69 Mutex*   StringDedupTable_lock        = NULL;
 70 Monitor* CodeCache_lock               = NULL;
 71 Mutex*   MethodData_lock              = NULL;
 72 Mutex*   TouchedMethodLog_lock        = NULL;
 73 Mutex*   RetData_lock                 = NULL;
 74 Monitor* VMOperationQueue_lock        = NULL;
 75 Monitor* VMOperationRequest_lock      = NULL;
 76 Monitor* Safepoint_lock               = NULL;
 77 Monitor* SerializePage_lock           = NULL;
 78 Monitor* Threads_lock                 = NULL;
 79 Mutex*   NonJavaThreadsList_lock      = NULL;
 80 Monitor* CGC_lock                     = NULL;
 81 Monitor* STS_lock                     = NULL;
 82 Monitor* FullGCCount_lock             = NULL;
 83 Mutex*   SATB_Q_FL_lock               = NULL;
 84 Monitor* SATB_Q_CBL_mon               = NULL;
 85 Mutex*   Shared_SATB_Q_lock           = NULL;
 86 Mutex*   DirtyCardQ_FL_lock           = NULL;
 87 Monitor* DirtyCardQ_CBL_mon           = NULL;
 88 Mutex*   Shared_DirtyCardQ_lock       = NULL;
 89 Mutex*   MarkStackFreeList_lock       = NULL;
 90 Mutex*   MarkStackChunkList_lock      = NULL;
 91 Mutex*   ParGCRareEvent_lock          = NULL;
 92 Mutex*   DerivedPointerTableGC_lock   = NULL;
 93 Monitor* CGCPhaseManager_lock         = NULL;
 94 Mutex*   Compile_lock                 = NULL;
 95 Monitor* MethodCompileQueue_lock      = NULL;
 96 Monitor* CompileThread_lock           = NULL;
 97 Monitor* Compilation_lock             = NULL;
 98 Mutex*   CompileTaskAlloc_lock        = NULL;
 99 Mutex*   CompileStatistics_lock       = NULL;
100 Mutex*   DirectivesStack_lock         = NULL;
101 Mutex*   MultiArray_lock              = NULL;
102 Monitor* Terminator_lock              = NULL;
103 Monitor* BeforeExit_lock              = NULL;
104 Monitor* Notify_lock                  = NULL;
105 Mutex*   ProfilePrint_lock            = NULL;
106 Mutex*   ExceptionCache_lock          = NULL;
107 Mutex*   OsrList_lock                 = NULL;
108 
109 #ifndef PRODUCT
110 Mutex*   FullGCALot_lock              = NULL;
111 #endif
112 
113 Mutex*   Debug1_lock                  = NULL;
114 Mutex*   Debug2_lock                  = NULL;
115 Mutex*   Debug3_lock                  = NULL;
116 
117 Mutex*   tty_lock                     = NULL;
118 
119 Mutex*   RawMonitor_lock              = NULL;
120 Mutex*   PerfDataMemAlloc_lock        = NULL;
121 Mutex*   PerfDataManager_lock         = NULL;
122 Mutex*   OopMapCacheAlloc_lock        = NULL;
123 
124 Mutex*   FreeList_lock                = NULL;
125 Mutex*   OldSets_lock                 = NULL;
126 Monitor* RootRegionScan_lock          = NULL;
127 
128 Monitor* GCTaskManager_lock           = NULL;
129 
130 Mutex*   Management_lock              = NULL;
131 Monitor* Service_lock                 = NULL;
132 Monitor* PeriodicTask_lock            = NULL;
133 Monitor* RedefineClasses_lock         = NULL;
134 
135 Mutex*   ThreadHeapSampler_lock       = NULL;
136 
137 #if INCLUDE_JFR
138 Mutex*   JfrStacktrace_lock           = NULL;
139 Monitor* JfrMsg_lock                  = NULL;
140 Mutex*   JfrBuffer_lock               = NULL;
141 Mutex*   JfrStream_lock               = NULL;
142 #endif
143 
144 #ifndef SUPPORTS_NATIVE_CX8
145 Mutex*   UnsafeJlong_lock             = NULL;
146 #endif
147 Monitor* CodeHeapStateAnalytics_lock  = NULL;
148 
149 Mutex*   MetaspaceExpand_lock         = NULL;
150 Mutex*   ClassLoaderDataGraph_lock    = NULL;
151 
152 #define MAX_NUM_MUTEX 128
153 static Monitor * _mutex_array[MAX_NUM_MUTEX];
154 static int _num_mutex;
155 
156 #ifdef ASSERT
157 void assert_locked_or_safepoint(const Monitor * lock) {
158   // check if this thread owns the lock (common case)
159   if (IgnoreLockingAssertions) return;
160   assert(lock != NULL, "Need non-NULL lock");
161   if (lock->owned_by_self()) return;
162   if (SafepointSynchronize::is_at_safepoint()) return;
163   if (!Universe::is_fully_initialized()) return;
164   // see if invoker of VM operation owns it
165   VM_Operation* op = VMThread::vm_operation();
166   if (op != NULL && op->calling_thread() == lock->owner()) return;
167   fatal("must own lock %s", lock->name());
168 }
169 
170 // a weaker assertion than the above
171 void assert_locked_or_safepoint_weak(const Monitor * lock) {
172   if (IgnoreLockingAssertions) return;
173   assert(lock != NULL, "Need non-NULL lock");
174   if (lock->is_locked()) return;
175   if (SafepointSynchronize::is_at_safepoint()) return;
176   if (!Universe::is_fully_initialized()) return;
177   fatal("must own lock %s", lock->name());
178 }
179 
180 // a stronger assertion than the above
181 void assert_lock_strong(const Monitor * lock) {
182   if (IgnoreLockingAssertions) return;
183   assert(lock != NULL, "Need non-NULL lock");
184   if (lock->owned_by_self()) return;
185   fatal("must own lock %s", lock->name());
186 }
187 #endif
188 
189 #define def(var, type, pri, vm_block, safepoint_check_allowed ) {      \
190   var = new type(Mutex::pri, #var, vm_block, safepoint_check_allowed); \
191   assert(_num_mutex < MAX_NUM_MUTEX, "increase MAX_NUM_MUTEX");        \
192   _mutex_array[_num_mutex++] = var;                                      \
193 }
194 
195 // Using Padded subclasses to prevent false sharing of these global monitors and mutexes.
196 void mutex_init() {
197   def(tty_lock                     , PaddedMutex  , event,       true,  Monitor::_safepoint_check_never);      // allow to lock in VM
198 
199   def(CGC_lock                     , PaddedMonitor, special,     true,  Monitor::_safepoint_check_never);      // coordinate between fore- and background GC
200   def(STS_lock                     , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);
201 
202   def(VMWeakAlloc_lock             , PaddedMutex  , vmweak,      true,  Monitor::_safepoint_check_never);
203   def(VMWeakActive_lock            , PaddedMutex  , vmweak-1,    true,  Monitor::_safepoint_check_never);
204 
205   def(StringTableWeakAlloc_lock    , PaddedMutex  , vmweak,      true,  Monitor::_safepoint_check_never);
206   def(StringTableWeakActive_lock   , PaddedMutex  , vmweak-1,    true,  Monitor::_safepoint_check_never);
207 
208   if (UseConcMarkSweepGC || UseG1GC) {
209     def(FullGCCount_lock           , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);      // in support of ExplicitGCInvokesConcurrent
210   }
211   if (UseG1GC) {
212     def(SATB_Q_FL_lock             , PaddedMutex  , access,      true,  Monitor::_safepoint_check_never);
213     def(SATB_Q_CBL_mon             , PaddedMonitor, access,      true,  Monitor::_safepoint_check_never);
214     def(Shared_SATB_Q_lock         , PaddedMutex  , access + 1,  true,  Monitor::_safepoint_check_never);
215 
216     def(DirtyCardQ_FL_lock         , PaddedMutex  , access,      true,  Monitor::_safepoint_check_never);
217     def(DirtyCardQ_CBL_mon         , PaddedMonitor, access,      true,  Monitor::_safepoint_check_never);
218     def(Shared_DirtyCardQ_lock     , PaddedMutex  , access + 1,  true,  Monitor::_safepoint_check_never);
219 
220     def(FreeList_lock              , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);
221     def(OldSets_lock               , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);
222     def(RootRegionScan_lock        , PaddedMonitor, leaf     ,   true,  Monitor::_safepoint_check_never);
223 
224     def(StringDedupQueue_lock      , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);
225     def(StringDedupTable_lock      , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
226 
227     def(MarkStackFreeList_lock     , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);
228     def(MarkStackChunkList_lock    , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);
229   }
230   def(ParGCRareEvent_lock          , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_sometimes);
231   def(DerivedPointerTableGC_lock   , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
232   def(CGCPhaseManager_lock         , PaddedMonitor, leaf,        false, Monitor::_safepoint_check_sometimes);
233   def(CodeCache_lock               , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);
234   def(RawMonitor_lock              , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);
235   def(OopMapCacheAlloc_lock        , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);     // used for oop_map_cache allocation.
236 
237   def(MetaspaceExpand_lock         , PaddedMutex  , leaf-1,      true,  Monitor::_safepoint_check_never);
238   def(ClassLoaderDataGraph_lock    , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_always);
239 
240   def(Patching_lock                , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);      // used for safepointing and code patching.
241   def(Service_lock                 , PaddedMonitor, special,     true,  Monitor::_safepoint_check_never);      // used for service thread operations
242   def(JmethodIdCreation_lock       , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);     // used for creating jmethodIDs.
243 
244   def(SystemDictionary_lock        , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);     // lookups done by VM thread
245   def(SharedDictionary_lock        , PaddedMutex,   leaf,        true,  Monitor::_safepoint_check_always);     // lookups done by VM thread
246   def(Module_lock                  , PaddedMutex  , leaf+2,      true,  Monitor::_safepoint_check_always);
247   def(InlineCacheBuffer_lock       , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);
248   def(VMStatistic_lock             , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);
249   def(ExpandHeap_lock              , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);     // Used during compilation by VM thread
250   def(JNIHandleBlockFreeList_lock  , PaddedMutex  , leaf-1,      true,  Monitor::_safepoint_check_never);      // handles are used by VM thread
251   def(SignatureHandlerLibrary_lock , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);
252   def(SymbolArena_lock             , PaddedMutex  , leaf+2,      true,  Monitor::_safepoint_check_never);
253   def(StringTable_lock             , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);
254   def(ProfilePrint_lock            , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);     // serial profile printing
255   def(ExceptionCache_lock          , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);     // serial profile printing
256   def(OsrList_lock                 , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
257   def(Debug1_lock                  , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
258 #ifndef PRODUCT
259   def(FullGCALot_lock              , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);     // a lock to make FullGCALot MT safe
260 #endif
261   def(BeforeExit_lock              , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);
262   def(PerfDataMemAlloc_lock        , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);     // used for allocating PerfData memory for performance data
263   def(PerfDataManager_lock         , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);     // used for synchronized access to PerfDataManager resources
264 
265   // CMS_modUnionTable_lock                   leaf
266   // CMS_bitMap_lock                          leaf 1
267   // CMS_freeList_lock                        leaf 2
268 
269   def(Safepoint_lock               , PaddedMonitor, safepoint,   true,  Monitor::_safepoint_check_sometimes);  // locks SnippetCache_lock/Threads_lock
270 
271   def(Threads_lock                 , PaddedMonitor, barrier,     true,  Monitor::_safepoint_check_sometimes);
272   def(NonJavaThreadsList_lock      , PaddedMutex,   leaf,        true,  Monitor::_safepoint_check_never);
273 
274   def(VMOperationQueue_lock        , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_sometimes);  // VM_thread allowed to block on these
275   def(VMOperationRequest_lock      , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_sometimes);
276   def(RetData_lock                 , PaddedMutex  , nonleaf,     false, Monitor::_safepoint_check_always);
277   def(Terminator_lock              , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_sometimes);
278   def(VtableStubs_lock             , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_always);
279   def(Notify_lock                  , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_always);
280   def(JNIGlobalAlloc_lock          , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_never);
281   def(JNIGlobalActive_lock         , PaddedMutex  , nonleaf-1,   true,  Monitor::_safepoint_check_never);
282   def(JNIWeakAlloc_lock            , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_never);
283   def(JNIWeakActive_lock           , PaddedMutex  , nonleaf-1,   true,  Monitor::_safepoint_check_never);
284   def(JNICritical_lock             , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_always);     // used for JNI critical regions
285   def(AdapterHandlerLibrary_lock   , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_always);
286 
287   def(Heap_lock                    , PaddedMonitor, nonleaf+1,   false, Monitor::_safepoint_check_sometimes);
288   def(JfieldIdCreation_lock        , PaddedMutex  , nonleaf+1,   true,  Monitor::_safepoint_check_always);     // jfieldID, Used in VM_Operation
289   def(ResolvedMethodTable_lock     , PaddedMutex  , nonleaf+1,   false, Monitor::_safepoint_check_always);     // Used to protect ResolvedMethodTable
290 
291   def(CompiledIC_lock              , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);     // locks VtableStubs_lock, InlineCacheBuffer_lock
292   def(CompileTaskAlloc_lock        , PaddedMutex  , nonleaf+2,   true,  Monitor::_safepoint_check_always);
293   def(CompileStatistics_lock       , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);
294   def(DirectivesStack_lock         , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);
295   def(MultiArray_lock              , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);
296 
297   def(JvmtiThreadState_lock        , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);     // Used by JvmtiThreadState/JvmtiEventController
298   def(Management_lock              , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);     // used for JVM management
299 
300   def(Compile_lock                 , PaddedMutex  , nonleaf+3,   true,  Monitor::_safepoint_check_sometimes);
301   def(MethodData_lock              , PaddedMutex  , nonleaf+3,   false, Monitor::_safepoint_check_always);
302   def(TouchedMethodLog_lock        , PaddedMutex  , nonleaf+3,   false, Monitor::_safepoint_check_always);
303 
304   def(MethodCompileQueue_lock      , PaddedMonitor, nonleaf+4,   true,  Monitor::_safepoint_check_always);
305   def(Debug2_lock                  , PaddedMutex  , nonleaf+4,   true,  Monitor::_safepoint_check_never);
306   def(Debug3_lock                  , PaddedMutex  , nonleaf+4,   true,  Monitor::_safepoint_check_never);
307   def(CompileThread_lock           , PaddedMonitor, nonleaf+5,   false, Monitor::_safepoint_check_always);
308   def(PeriodicTask_lock            , PaddedMonitor, nonleaf+5,   true,  Monitor::_safepoint_check_sometimes);
309   def(RedefineClasses_lock         , PaddedMonitor, nonleaf+5,   true,  Monitor::_safepoint_check_always);
310 
311   def(ThreadHeapSampler_lock       , PaddedMutex,   nonleaf,     false, Monitor::_safepoint_check_never);
312 
313   if (WhiteBoxAPI) {
314     def(Compilation_lock           , PaddedMonitor, leaf,        false, Monitor::_safepoint_check_never);
315   }
316 
317 #if INCLUDE_JFR
318   def(JfrMsg_lock                  , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);
319   def(JfrBuffer_lock               , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
320   def(JfrStream_lock               , PaddedMutex  , leaf+1,      true,  Monitor::_safepoint_check_never);      // ensure to rank lower than 'safepoint'
321   def(JfrStacktrace_lock           , PaddedMutex  , special,     true,  Monitor::_safepoint_check_sometimes);
322 #endif
323 
324 #ifndef SUPPORTS_NATIVE_CX8
325   def(UnsafeJlong_lock             , PaddedMutex  , special,     false, Monitor::_safepoint_check_never);
326 #endif
327 
328   def(CodeHeapStateAnalytics_lock  , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
329 }
330 
331 GCMutexLocker::GCMutexLocker(Monitor * mutex) {
332   if (SafepointSynchronize::is_at_safepoint()) {
333     _locked = false;
334   } else {
335     _mutex = mutex;
336     _locked = true;
337     _mutex->lock();
338   }
339 }
340 
341 // Print all mutexes/monitors that are currently owned by a thread; called
342 // by fatal error handler.
343 void print_owned_locks_on_error(outputStream* st) {
344   st->print("VM Mutex/Monitor currently owned by a thread: ");
345   bool none = true;
346   for (int i = 0; i < _num_mutex; i++) {
347      // see if it has an owner
348      if (_mutex_array[i]->owner() != NULL) {
349        if (none) {
350           // print format used by Mutex::print_on_error()
351           st->print_cr(" ([mutex/lock_event])");
352           none = false;
353        }
354        _mutex_array[i]->print_on_error(st);
355        st->cr();
356      }
357   }
358   if (none) st->print_cr("None");
359 }