1 /*
   2  * Copyright (c) 1997, 2019, 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 "memory/universe.hpp"
  27 #include "runtime/mutexLocker.hpp"
  28 #include "runtime/os.inline.hpp"
  29 #include "runtime/safepoint.hpp"
  30 #include "runtime/thread.inline.hpp"
  31 #include "runtime/vmThread.hpp"
  32 
  33 // Mutexes used in the VM (see comment in mutexLocker.hpp):
  34 //
  35 // Note that the following pointers are effectively final -- after having been
  36 // set at JVM startup-time, they should never be subsequently mutated.
  37 // Instead of using pointers to malloc()ed monitors and mutexes we should consider
  38 // eliminating the indirection and using instances instead.
  39 // Consider using GCC's __read_mostly.
  40 
  41 Mutex*   Patching_lock                = NULL;
  42 Monitor* SystemDictionary_lock        = NULL;
  43 Mutex*   ProtectionDomainSet_lock     = NULL;
  44 Mutex*   SharedDictionary_lock        = NULL;
  45 Mutex*   Module_lock                  = NULL;
  46 Mutex*   CompiledIC_lock              = NULL;
  47 Mutex*   InlineCacheBuffer_lock       = NULL;
  48 Mutex*   VMStatistic_lock             = NULL;
  49 Mutex*   JNIHandleBlockFreeList_lock  = NULL;
  50 Mutex*   JmethodIdCreation_lock       = NULL;
  51 Mutex*   JfieldIdCreation_lock        = NULL;
  52 Monitor* JNICritical_lock             = NULL;
  53 Mutex*   JvmtiThreadState_lock        = NULL;
  54 Monitor* Heap_lock                    = NULL;
  55 Mutex*   ExpandHeap_lock              = NULL;
  56 Mutex*   AdapterHandlerLibrary_lock   = NULL;
  57 Mutex*   SignatureHandlerLibrary_lock = NULL;
  58 Mutex*   VtableStubs_lock             = NULL;
  59 Mutex*   SymbolArena_lock             = NULL;
  60 Monitor* StringDedupQueue_lock        = NULL;
  61 Mutex*   StringDedupTable_lock        = NULL;
  62 Monitor* CodeCache_lock               = NULL;
  63 Mutex*   MethodData_lock              = NULL;
  64 Mutex*   TouchedMethodLog_lock        = NULL;
  65 Mutex*   RetData_lock                 = NULL;
  66 Monitor* VMOperationQueue_lock        = NULL;
  67 Monitor* VMOperationRequest_lock      = NULL;
  68 Monitor* SerializePage_lock           = NULL;
  69 Monitor* Threads_lock                 = NULL;
  70 Mutex*   NonJavaThreadsList_lock      = NULL;
  71 Mutex*   NonJavaThreadsListSync_lock  = NULL;
  72 Monitor* CGC_lock                     = NULL;
  73 Monitor* STS_lock                     = NULL;
  74 Monitor* FullGCCount_lock             = NULL;
  75 Monitor* DirtyCardQ_CBL_mon           = NULL;
  76 Mutex*   Shared_DirtyCardQ_lock       = NULL;
  77 Mutex*   MarkStackFreeList_lock       = NULL;
  78 Mutex*   MarkStackChunkList_lock      = NULL;
  79 Mutex*   MonitoringSupport_lock       = NULL;
  80 Mutex*   ParGCRareEvent_lock          = NULL;
  81 Monitor* CGCPhaseManager_lock         = NULL;
  82 Mutex*   Compile_lock                 = NULL;
  83 Monitor* MethodCompileQueue_lock      = NULL;
  84 Monitor* CompileThread_lock           = NULL;
  85 Monitor* Compilation_lock             = NULL;
  86 Mutex*   CompileTaskAlloc_lock        = NULL;
  87 Mutex*   CompileStatistics_lock       = NULL;
  88 Mutex*   DirectivesStack_lock         = NULL;
  89 Mutex*   MultiArray_lock              = NULL;
  90 Monitor* Terminator_lock              = NULL;
  91 Monitor* InitCompleted_lock           = NULL;
  92 Monitor* BeforeExit_lock              = NULL;
  93 Monitor* Notify_lock                  = NULL;
  94 Mutex*   ProfilePrint_lock            = NULL;
  95 Mutex*   ExceptionCache_lock          = NULL;
  96 Mutex*   OsrList_lock                 = NULL;
  97 Mutex*   NMethodSweeperStats_lock     = NULL;
  98 #ifndef PRODUCT
  99 Mutex*   FullGCALot_lock              = NULL;
 100 #endif
 101 
 102 Mutex*   Debug1_lock                  = NULL;
 103 Mutex*   Debug2_lock                  = NULL;
 104 Mutex*   Debug3_lock                  = NULL;
 105 
 106 Mutex*   tty_lock                     = NULL;
 107 
 108 Mutex*   RawMonitor_lock              = NULL;
 109 Mutex*   PerfDataMemAlloc_lock        = NULL;
 110 Mutex*   PerfDataManager_lock         = NULL;
 111 Mutex*   OopMapCacheAlloc_lock        = NULL;
 112 
 113 Mutex*   FreeList_lock                = NULL;
 114 Mutex*   OldSets_lock                 = NULL;
 115 Monitor* RootRegionScan_lock          = NULL;
 116 
 117 Mutex*   Management_lock              = NULL;
 118 Monitor* Service_lock                 = NULL;
 119 Monitor* PeriodicTask_lock            = NULL;
 120 Monitor* RedefineClasses_lock         = NULL;
 121 
 122 #if INCLUDE_JFR
 123 Mutex*   JfrStacktrace_lock           = NULL;
 124 Monitor* JfrMsg_lock                  = NULL;
 125 Mutex*   JfrBuffer_lock               = NULL;
 126 Mutex*   JfrStream_lock               = NULL;
 127 Monitor* JfrThreadSampler_lock        = NULL;
 128 #endif
 129 
 130 #ifndef SUPPORTS_NATIVE_CX8
 131 Mutex*   UnsafeJlong_lock             = NULL;
 132 #endif
 133 Mutex*   CodeHeapStateAnalytics_lock  = NULL;
 134 
 135 Mutex*   MetaspaceExpand_lock         = NULL;
 136 Mutex*   ClassLoaderDataGraph_lock    = NULL;
 137 Monitor* ThreadsSMRDelete_lock        = NULL;
 138 Mutex*   SharedDecoder_lock           = NULL;
 139 Mutex*   DCmdFactory_lock             = NULL;
 140 #if INCLUDE_NMT
 141 Mutex*   NMTQuery_lock                = NULL;
 142 #endif
 143 #if INCLUDE_CDS
 144 #if INCLUDE_JVMTI
 145 Mutex*   CDSClassFileStream_lock      = NULL;
 146 #endif
 147 Mutex*   DumpTimeTable_lock           = NULL;
 148 #endif // INCLUDE_CDS
 149 
 150 #if INCLUDE_JVMCI
 151 Monitor* JVMCI_lock                   = NULL;
 152 #endif
 153 
 154 
 155 #define MAX_NUM_MUTEX 128
 156 static Mutex* _mutex_array[MAX_NUM_MUTEX];
 157 static int _num_mutex;
 158 
 159 #ifdef ASSERT
 160 void assert_locked_or_safepoint(const Mutex* lock) {
 161   // check if this thread owns the lock (common case)
 162   if (IgnoreLockingAssertions) return;
 163   assert(lock != NULL, "Need non-NULL lock");
 164   if (lock->owned_by_self()) return;
 165   if (SafepointSynchronize::is_at_safepoint()) return;
 166   if (!Universe::is_fully_initialized()) return;
 167   // see if invoker of VM operation owns it
 168   VM_Operation* op = VMThread::vm_operation();
 169   if (op != NULL && op->calling_thread() == lock->owner()) return;
 170   fatal("must own lock %s", lock->name());
 171 }
 172 
 173 // a weaker assertion than the above
 174 void assert_locked_or_safepoint_weak(const Mutex* lock) {
 175   if (IgnoreLockingAssertions) return;
 176   assert(lock != NULL, "Need non-NULL lock");
 177   if (lock->is_locked()) return;
 178   if (SafepointSynchronize::is_at_safepoint()) return;
 179   if (!Universe::is_fully_initialized()) return;
 180   fatal("must own lock %s", lock->name());
 181 }
 182 
 183 // a stronger assertion than the above
 184 void assert_lock_strong(const Mutex* lock) {
 185   if (IgnoreLockingAssertions) return;
 186   assert(lock != NULL, "Need non-NULL lock");
 187   if (lock->owned_by_self()) return;
 188   fatal("must own lock %s", lock->name());
 189 }
 190 #endif
 191 
 192 #define def(var, type, pri, vm_block, safepoint_check_allowed ) {      \
 193   var = new type(Mutex::pri, #var, vm_block, safepoint_check_allowed); \
 194   assert(_num_mutex < MAX_NUM_MUTEX, "increase MAX_NUM_MUTEX");        \
 195   _mutex_array[_num_mutex++] = var;                                      \
 196 }
 197 
 198 // Using Padded subclasses to prevent false sharing of these global monitors and mutexes.
 199 void mutex_init() {
 200   def(tty_lock                     , PaddedMutex  , tty,         true,  Monitor::_safepoint_check_never);      // allow to lock in VM
 201 
 202   def(CGC_lock                     , PaddedMonitor, special,     true,  Monitor::_safepoint_check_never);      // coordinate between fore- and background GC
 203   def(STS_lock                     , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);
 204 
 205   def(FullGCCount_lock             , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);      // in support of ExplicitGCInvokesConcurrent
 206   if (UseG1GC) {
 207     def(DirtyCardQ_CBL_mon         , PaddedMonitor, access,      true,  Monitor::_safepoint_check_never);
 208     def(Shared_DirtyCardQ_lock     , PaddedMutex  , access + 1,  true,  Monitor::_safepoint_check_never);
 209 
 210     def(FreeList_lock              , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);
 211     def(OldSets_lock               , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);
 212     def(RootRegionScan_lock        , PaddedMonitor, leaf     ,   true,  Monitor::_safepoint_check_never);
 213 
 214     def(StringDedupQueue_lock      , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);
 215     def(StringDedupTable_lock      , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 216 
 217     def(MarkStackFreeList_lock     , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);
 218     def(MarkStackChunkList_lock    , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);
 219 
 220     def(MonitoringSupport_lock     , PaddedMutex  , native   ,   true,  Monitor::_safepoint_check_never);      // used for serviceability monitoring support
 221   }
 222   if (UseShenandoahGC) {
 223     def(StringDedupQueue_lock      , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);
 224     def(StringDedupTable_lock      , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 225   }
 226   def(ParGCRareEvent_lock          , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_always);
 227   def(CGCPhaseManager_lock         , PaddedMonitor, leaf,        false, Monitor::_safepoint_check_always);
 228   def(CodeCache_lock               , PaddedMonitor, special,     true,  Monitor::_safepoint_check_never);
 229   def(RawMonitor_lock              , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);
 230   def(OopMapCacheAlloc_lock        , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always); // used for oop_map_cache allocation.
 231 
 232   def(MetaspaceExpand_lock         , PaddedMutex  , leaf-1,      true,  Monitor::_safepoint_check_never);
 233   def(ClassLoaderDataGraph_lock    , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_always);
 234 
 235   def(Patching_lock                , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);      // used for safepointing and code patching.
 236   def(Service_lock                 , PaddedMonitor, special,     true,  Monitor::_safepoint_check_never);      // used for service thread operations
 237   def(JmethodIdCreation_lock       , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always); // used for creating jmethodIDs.
 238 
 239   def(SystemDictionary_lock        , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);
 240   def(ProtectionDomainSet_lock     , PaddedMutex  , leaf-1,      true,  Monitor::_safepoint_check_never);
 241   def(SharedDictionary_lock        , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);
 242   def(Module_lock                  , PaddedMutex  , leaf+2,      true,  Monitor::_safepoint_check_always);
 243   def(InlineCacheBuffer_lock       , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 244   def(VMStatistic_lock             , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);
 245   def(ExpandHeap_lock              , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always); // Used during compilation by VM thread
 246   def(JNIHandleBlockFreeList_lock  , PaddedMutex  , leaf-1,      true,  Monitor::_safepoint_check_never);      // handles are used by VM thread
 247   def(SignatureHandlerLibrary_lock , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);
 248   def(SymbolArena_lock             , PaddedMutex  , leaf+2,      true,  Monitor::_safepoint_check_never);
 249   def(ProfilePrint_lock            , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always); // serial profile printing
 250   def(ExceptionCache_lock          , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always); // serial profile printing
 251   def(OsrList_lock                 , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 252   def(Debug1_lock                  , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 253 #ifndef PRODUCT
 254   def(FullGCALot_lock              , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always); // a lock to make FullGCALot MT safe
 255 #endif
 256   def(BeforeExit_lock              , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);
 257   def(PerfDataMemAlloc_lock        , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always); // used for allocating PerfData memory for performance data
 258   def(PerfDataManager_lock         , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always); // used for synchronized access to PerfDataManager resources
 259 
 260   // CMS_modUnionTable_lock                   leaf
 261   // CMS_bitMap_lock                          leaf 1
 262   // CMS_freeList_lock                        leaf 2
 263 
 264   def(Threads_lock                 , PaddedMonitor, barrier,     true,  Monitor::_safepoint_check_always);  // Used for safepoint protocol.
 265   def(NonJavaThreadsList_lock      , PaddedMutex,   leaf,        true,  Monitor::_safepoint_check_never);
 266   def(NonJavaThreadsListSync_lock  , PaddedMutex,   leaf,        true,  Monitor::_safepoint_check_never);
 267 
 268   def(VMOperationQueue_lock        , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_never);  // VM_thread allowed to block on these
 269   def(VMOperationRequest_lock      , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_always);
 270   def(RetData_lock                 , PaddedMutex  , nonleaf,     false, Monitor::_safepoint_check_always);
 271   def(Terminator_lock              , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_always);
 272   def(InitCompleted_lock           , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);
 273   def(VtableStubs_lock             , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_never);
 274   def(Notify_lock                  , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_always);
 275   def(JNICritical_lock             , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_always); // used for JNI critical regions
 276   def(AdapterHandlerLibrary_lock   , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_always);
 277 
 278   def(Heap_lock                    , PaddedMonitor, nonleaf+1,   false, Monitor::_safepoint_check_sometimes);  // Doesn't safepoint check during termination.
 279   def(JfieldIdCreation_lock        , PaddedMutex  , nonleaf+1,   true,  Monitor::_safepoint_check_always); // jfieldID, Used in VM_Operation
 280 
 281   def(CompiledIC_lock              , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_never);      // locks VtableStubs_lock, InlineCacheBuffer_lock
 282   def(CompileTaskAlloc_lock        , PaddedMutex  , nonleaf+2,   true,  Monitor::_safepoint_check_always);
 283   def(CompileStatistics_lock       , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);
 284   def(DirectivesStack_lock         , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);
 285   def(MultiArray_lock              , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);
 286 
 287   def(JvmtiThreadState_lock        , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always); // Used by JvmtiThreadState/JvmtiEventController
 288   def(Management_lock              , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always); // used for JVM management
 289 
 290   def(Compile_lock                 , PaddedMutex  , nonleaf+3,   true,  Monitor::_safepoint_check_always);
 291   def(MethodData_lock              , PaddedMutex  , nonleaf+3,   false, Monitor::_safepoint_check_always);
 292   def(TouchedMethodLog_lock        , PaddedMutex  , nonleaf+3,   false, Monitor::_safepoint_check_always);
 293 
 294   def(MethodCompileQueue_lock      , PaddedMonitor, nonleaf+4,   true,  Monitor::_safepoint_check_always);
 295   def(Debug2_lock                  , PaddedMutex  , nonleaf+4,   true,  Monitor::_safepoint_check_never);
 296   def(Debug3_lock                  , PaddedMutex  , nonleaf+4,   true,  Monitor::_safepoint_check_never);
 297   def(CompileThread_lock           , PaddedMonitor, nonleaf+5,   false, Monitor::_safepoint_check_always);
 298   def(PeriodicTask_lock            , PaddedMonitor, nonleaf+5,   true,  Monitor::_safepoint_check_always);
 299   def(RedefineClasses_lock         , PaddedMonitor, nonleaf+5,   true,  Monitor::_safepoint_check_always);
 300 
 301   if (WhiteBoxAPI) {
 302     def(Compilation_lock           , PaddedMonitor, leaf,        false, Monitor::_safepoint_check_never);
 303   }
 304 
 305 #if INCLUDE_JFR
 306   def(JfrMsg_lock                  , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);
 307   def(JfrBuffer_lock               , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 308   def(JfrStream_lock               , PaddedMutex  , leaf+1,      true,  Monitor::_safepoint_check_never);      // ensure to rank lower than 'safepoint'
 309   def(JfrStacktrace_lock           , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);
 310   def(JfrThreadSampler_lock        , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);
 311 #endif
 312 
 313 #ifndef SUPPORTS_NATIVE_CX8
 314   def(UnsafeJlong_lock             , PaddedMutex  , special,     false, Monitor::_safepoint_check_never);
 315 #endif
 316 
 317   def(CodeHeapStateAnalytics_lock  , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 318   def(NMethodSweeperStats_lock     , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);
 319   def(ThreadsSMRDelete_lock        , PaddedMonitor, special,     false, Monitor::_safepoint_check_never);
 320   def(SharedDecoder_lock           , PaddedMutex  , native,      false, Monitor::_safepoint_check_never);
 321   def(DCmdFactory_lock             , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 322 #if INCLUDE_NMT
 323   def(NMTQuery_lock                , PaddedMutex  , max_nonleaf, false, Monitor::_safepoint_check_always);
 324 #endif
 325 #if INCLUDE_CDS
 326 #if INCLUDE_JVMTI
 327   def(CDSClassFileStream_lock      , PaddedMutex  , max_nonleaf, false, Monitor::_safepoint_check_always);
 328 #endif
 329 
 330 #if INCLUDE_JVMCI
 331   def(JVMCI_lock                   , PaddedMonitor, nonleaf+2,   true,  Monitor::_safepoint_check_always);
 332 #endif
 333   def(DumpTimeTable_lock           , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 334 #endif // INCLUDE_CDS
 335 }
 336 
 337 GCMutexLocker::GCMutexLocker(Mutex* mutex) {
 338   if (SafepointSynchronize::is_at_safepoint()) {
 339     _locked = false;
 340   } else {
 341     _mutex = mutex;
 342     _locked = true;
 343     _mutex->lock();
 344   }
 345 }
 346 
 347 // Print all mutexes/monitors that are currently owned by a thread; called
 348 // by fatal error handler.
 349 void print_owned_locks_on_error(outputStream* st) {
 350   st->print("VM Mutex/Monitor currently owned by a thread: ");
 351   bool none = true;
 352   for (int i = 0; i < _num_mutex; i++) {
 353      // see if it has an owner
 354      if (_mutex_array[i]->owner() != NULL) {
 355        if (none) {
 356           // print format used by Mutex::print_on_error()
 357           st->print_cr(" ([mutex/lock_event])");
 358           none = false;
 359        }
 360        _mutex_array[i]->print_on_error(st);
 361        st->cr();
 362      }
 363   }
 364   if (none) st->print_cr("None");
 365 }