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*   SymbolTable_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 Monitor* CGC_lock                     = NULL;
  80 Monitor* STS_lock                     = NULL;
  81 Monitor* FullGCCount_lock             = NULL;
  82 Mutex*   SATB_Q_FL_lock               = NULL;
  83 Monitor* SATB_Q_CBL_mon               = NULL;
  84 Mutex*   Shared_SATB_Q_lock           = NULL;
  85 Mutex*   DirtyCardQ_FL_lock           = NULL;
  86 Monitor* DirtyCardQ_CBL_mon           = NULL;
  87 Mutex*   Shared_DirtyCardQ_lock       = NULL;
  88 Mutex*   MarkStackFreeList_lock       = NULL;
  89 Mutex*   MarkStackChunkList_lock      = NULL;
  90 Mutex*   ParGCRareEvent_lock          = NULL;
  91 Mutex*   DerivedPointerTableGC_lock   = NULL;
  92 Monitor* CGCPhaseManager_lock         = NULL;
  93 Mutex*   Compile_lock                 = NULL;
  94 Monitor* MethodCompileQueue_lock      = NULL;
  95 Monitor* CompileThread_lock           = NULL;
  96 Monitor* Compilation_lock             = NULL;
  97 Mutex*   CompileTaskAlloc_lock        = NULL;
  98 Mutex*   CompileStatistics_lock       = NULL;
  99 Mutex*   DirectivesStack_lock         = NULL;
 100 Mutex*   MultiArray_lock              = NULL;
 101 Monitor* Terminator_lock              = NULL;
 102 Monitor* BeforeExit_lock              = NULL;
 103 Monitor* Notify_lock                  = NULL;
 104 Mutex*   ProfilePrint_lock            = NULL;
 105 Mutex*   ExceptionCache_lock          = NULL;
 106 Mutex*   OsrList_lock                 = NULL;
 107 
 108 #ifndef PRODUCT
 109 Mutex*   FullGCALot_lock              = NULL;
 110 #endif
 111 
 112 Mutex*   Debug1_lock                  = NULL;
 113 Mutex*   Debug2_lock                  = NULL;
 114 Mutex*   Debug3_lock                  = NULL;
 115 
 116 Mutex*   tty_lock                     = NULL;
 117 
 118 Mutex*   RawMonitor_lock              = NULL;
 119 Mutex*   PerfDataMemAlloc_lock        = NULL;
 120 Mutex*   PerfDataManager_lock         = NULL;
 121 Mutex*   OopMapCacheAlloc_lock        = NULL;
 122 
 123 Mutex*   FreeList_lock                = NULL;
 124 Mutex*   OldSets_lock                 = NULL;
 125 Monitor* RootRegionScan_lock          = NULL;
 126 
 127 Monitor* GCTaskManager_lock           = NULL;
 128 
 129 Mutex*   Management_lock              = NULL;
 130 Monitor* Service_lock                 = NULL;
 131 Monitor* PeriodicTask_lock            = NULL;
 132 Monitor* RedefineClasses_lock         = NULL;
 133 
 134 Mutex*   ThreadHeapSampler_lock       = NULL;
 135 
 136 #if INCLUDE_JFR
 137 Mutex*   JfrStacktrace_lock           = NULL;
 138 Monitor* JfrMsg_lock                  = NULL;
 139 Mutex*   JfrBuffer_lock               = NULL;
 140 Mutex*   JfrStream_lock               = NULL;
 141 #endif
 142 
 143 #ifndef SUPPORTS_NATIVE_CX8
 144 Mutex*   UnsafeJlong_lock             = NULL;
 145 #endif
 146 Monitor* CodeHeapStateAnalytics_lock  = NULL;
 147 
 148 Mutex*   MetaspaceExpand_lock         = NULL;
 149 
 150 #define MAX_NUM_MUTEX 128
 151 static Monitor * _mutex_array[MAX_NUM_MUTEX];
 152 static int _num_mutex;
 153 
 154 #ifdef ASSERT
 155 void assert_locked_or_safepoint(const Monitor * lock) {
 156   // check if this thread owns the lock (common case)
 157   if (IgnoreLockingAssertions) return;
 158   assert(lock != NULL, "Need non-NULL lock");
 159   if (lock->owned_by_self()) return;
 160   if (SafepointSynchronize::is_at_safepoint()) return;
 161   if (!Universe::is_fully_initialized()) return;
 162   // see if invoker of VM operation owns it
 163   VM_Operation* op = VMThread::vm_operation();
 164   if (op != NULL && op->calling_thread() == lock->owner()) return;
 165   fatal("must own lock %s", lock->name());
 166 }
 167 
 168 // a stronger assertion than the above
 169 void assert_lock_strong(const Monitor * lock) {
 170   if (IgnoreLockingAssertions) return;
 171   assert(lock != NULL, "Need non-NULL lock");
 172   if (lock->owned_by_self()) return;
 173   fatal("must own lock %s", lock->name());
 174 }
 175 #endif
 176 
 177 #define def(var, type, pri, vm_block, safepoint_check_allowed ) {      \
 178   var = new type(Mutex::pri, #var, vm_block, safepoint_check_allowed); \
 179   assert(_num_mutex < MAX_NUM_MUTEX, "increase MAX_NUM_MUTEX");        \
 180   _mutex_array[_num_mutex++] = var;                                      \
 181 }
 182 
 183 // Using Padded subclasses to prevent false sharing of these global monitors and mutexes.
 184 void mutex_init() {
 185   def(tty_lock                     , PaddedMutex  , tty,         true,  Monitor::_safepoint_check_never);      // allow to lock in VM
 186 
 187   def(CGC_lock                     , PaddedMonitor, special,     true,  Monitor::_safepoint_check_never);      // coordinate between fore- and background GC
 188   def(STS_lock                     , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);
 189 
 190   def(VMWeakAlloc_lock             , PaddedMutex  , vmweak,      true,  Monitor::_safepoint_check_never);
 191   def(VMWeakActive_lock            , PaddedMutex  , vmweak-1,    true,  Monitor::_safepoint_check_never);
 192 
 193   def(StringTableWeakAlloc_lock    , PaddedMutex  , vmweak,      true,  Monitor::_safepoint_check_never);
 194   def(StringTableWeakActive_lock   , PaddedMutex  , vmweak-1,    true,  Monitor::_safepoint_check_never);
 195 
 196   if (UseConcMarkSweepGC || UseG1GC) {
 197     def(FullGCCount_lock           , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);      // in support of ExplicitGCInvokesConcurrent
 198   }
 199   if (UseG1GC) {
 200     def(SATB_Q_FL_lock             , PaddedMutex  , access,      true,  Monitor::_safepoint_check_never);
 201     def(SATB_Q_CBL_mon             , PaddedMonitor, access,      true,  Monitor::_safepoint_check_never);
 202     def(Shared_SATB_Q_lock         , PaddedMutex  , access + 1,  true,  Monitor::_safepoint_check_never);
 203 
 204     def(DirtyCardQ_FL_lock         , PaddedMutex  , access,      true,  Monitor::_safepoint_check_never);
 205     def(DirtyCardQ_CBL_mon         , PaddedMonitor, access,      true,  Monitor::_safepoint_check_never);
 206     def(Shared_DirtyCardQ_lock     , PaddedMutex  , access + 1,  true,  Monitor::_safepoint_check_never);
 207 
 208     def(FreeList_lock              , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);
 209     def(OldSets_lock               , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);
 210     def(RootRegionScan_lock        , PaddedMonitor, leaf     ,   true,  Monitor::_safepoint_check_never);
 211 
 212     def(StringDedupQueue_lock      , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);
 213     def(StringDedupTable_lock      , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 214 
 215     def(MarkStackFreeList_lock     , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);
 216     def(MarkStackChunkList_lock    , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);
 217   }
 218   def(ParGCRareEvent_lock          , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_sometimes);
 219   def(DerivedPointerTableGC_lock   , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 220   def(CGCPhaseManager_lock         , PaddedMonitor, leaf,        false, Monitor::_safepoint_check_sometimes);
 221   def(CodeCache_lock               , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);
 222   def(RawMonitor_lock              , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);
 223   def(OopMapCacheAlloc_lock        , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);     // used for oop_map_cache allocation.
 224 
 225   def(MetaspaceExpand_lock         , PaddedMutex  , leaf-1,      true,  Monitor::_safepoint_check_never);
 226 
 227   def(Patching_lock                , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);      // used for safepointing and code patching.
 228   def(Service_lock                 , PaddedMonitor, special,     true,  Monitor::_safepoint_check_never);      // used for service thread operations
 229   def(JmethodIdCreation_lock       , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);     // used for creating jmethodIDs.
 230 
 231   def(SystemDictionary_lock        , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);     // lookups done by VM thread
 232   def(SharedDictionary_lock        , PaddedMutex,   leaf,        true,  Monitor::_safepoint_check_always);     // lookups done by VM thread
 233   def(Module_lock                  , PaddedMutex  , leaf+2,      true,  Monitor::_safepoint_check_always);
 234   def(InlineCacheBuffer_lock       , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);
 235   def(VMStatistic_lock             , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);
 236   def(ExpandHeap_lock              , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);     // Used during compilation by VM thread
 237   def(JNIHandleBlockFreeList_lock  , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);      // handles are used by VM thread
 238   def(SignatureHandlerLibrary_lock , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);
 239   def(SymbolTable_lock             , PaddedMutex  , leaf+2,      true,  Monitor::_safepoint_check_always);
 240   def(StringTable_lock             , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);
 241   def(ProfilePrint_lock            , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);     // serial profile printing
 242   def(ExceptionCache_lock          , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);     // serial profile printing
 243   def(OsrList_lock                 , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 244   def(Debug1_lock                  , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 245 #ifndef PRODUCT
 246   def(FullGCALot_lock              , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);     // a lock to make FullGCALot MT safe
 247 #endif
 248   def(BeforeExit_lock              , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);
 249   def(PerfDataMemAlloc_lock        , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);     // used for allocating PerfData memory for performance data
 250   def(PerfDataManager_lock         , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);     // used for synchronized access to PerfDataManager resources
 251 
 252   // CMS_modUnionTable_lock                   leaf
 253   // CMS_bitMap_lock                          leaf 1
 254   // CMS_freeList_lock                        leaf 2
 255 
 256   def(Safepoint_lock               , PaddedMonitor, safepoint,   true,  Monitor::_safepoint_check_sometimes);  // locks SnippetCache_lock/Threads_lock
 257 
 258   def(Threads_lock                 , PaddedMonitor, barrier,     true,  Monitor::_safepoint_check_sometimes);
 259 
 260   def(VMOperationQueue_lock        , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_sometimes);  // VM_thread allowed to block on these
 261   def(VMOperationRequest_lock      , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_sometimes);
 262   def(RetData_lock                 , PaddedMutex  , nonleaf,     false, Monitor::_safepoint_check_always);
 263   def(Terminator_lock              , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_sometimes);
 264   def(VtableStubs_lock             , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_always);
 265   def(Notify_lock                  , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_always);
 266   // OopStorage-based JNI may lock the alloc_locks while releasing a handle,
 267   // while previous JNI didn't need a lock for handle release.  This runs afoul
 268   // of some places which hold other locks while releasing a handle, including
 269   // the Patching_lock, which is of "special" rank.  As a temporary workaround,
 270   // lower the JNI oopstorage lock ranks to make them super-special.
 271   def(JNIGlobalAlloc_lock          , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_never);
 272   def(JNIGlobalActive_lock         , PaddedMutex  , nonleaf-1,   true,  Monitor::_safepoint_check_never);
 273   def(JNIWeakAlloc_lock            , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_never);
 274   def(JNIWeakActive_lock           , PaddedMutex  , nonleaf-1,   true,  Monitor::_safepoint_check_never);
 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);
 279   def(JfieldIdCreation_lock        , PaddedMutex  , nonleaf+1,   true,  Monitor::_safepoint_check_always);     // jfieldID, Used in VM_Operation
 280   def(ResolvedMethodTable_lock     , PaddedMutex  , nonleaf+1,   false, Monitor::_safepoint_check_always);     // Used to protect ResolvedMethodTable
 281 
 282   def(CompiledIC_lock              , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);     // locks VtableStubs_lock, InlineCacheBuffer_lock
 283   def(CompileTaskAlloc_lock        , PaddedMutex  , nonleaf+2,   true,  Monitor::_safepoint_check_always);
 284   def(CompileStatistics_lock       , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);
 285   def(DirectivesStack_lock         , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);
 286   def(MultiArray_lock              , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);     // locks SymbolTable_lock
 287 
 288   def(JvmtiThreadState_lock        , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);     // Used by JvmtiThreadState/JvmtiEventController
 289   def(Management_lock              , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);     // used for JVM management
 290 
 291   def(Compile_lock                 , PaddedMutex  , nonleaf+3,   true,  Monitor::_safepoint_check_sometimes);
 292   def(MethodData_lock              , PaddedMutex  , nonleaf+3,   false, Monitor::_safepoint_check_always);
 293   def(TouchedMethodLog_lock        , PaddedMutex  , nonleaf+3,   false, Monitor::_safepoint_check_always);
 294 
 295   def(MethodCompileQueue_lock      , PaddedMonitor, nonleaf+4,   true,  Monitor::_safepoint_check_always);
 296   def(Debug2_lock                  , PaddedMutex  , nonleaf+4,   true,  Monitor::_safepoint_check_never);
 297   def(Debug3_lock                  , PaddedMutex  , nonleaf+4,   true,  Monitor::_safepoint_check_never);
 298   def(CompileThread_lock           , PaddedMonitor, nonleaf+5,   false, Monitor::_safepoint_check_always);
 299   def(PeriodicTask_lock            , PaddedMonitor, nonleaf+5,   true,  Monitor::_safepoint_check_sometimes);
 300   def(RedefineClasses_lock         , PaddedMonitor, nonleaf+5,   true,  Monitor::_safepoint_check_always);
 301 
 302   def(ThreadHeapSampler_lock       , PaddedMutex,   nonleaf,     false, Monitor::_safepoint_check_never);
 303 
 304   if (WhiteBoxAPI) {
 305     def(Compilation_lock           , PaddedMonitor, leaf,        false, Monitor::_safepoint_check_never);
 306   }
 307 
 308 #if INCLUDE_JFR
 309   def(JfrMsg_lock                  , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);
 310   def(JfrBuffer_lock               , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 311   def(JfrStream_lock               , PaddedMutex  , leaf+1,      true,  Monitor::_safepoint_check_never);      // ensure to rank lower than 'safepoint'
 312   def(JfrStacktrace_lock           , PaddedMutex  , special,     true,  Monitor::_safepoint_check_sometimes);
 313 #endif
 314 
 315 #ifndef SUPPORTS_NATIVE_CX8
 316   def(UnsafeJlong_lock             , PaddedMutex  , special,     false, Monitor::_safepoint_check_never);
 317 #endif
 318 
 319   def(CodeHeapStateAnalytics_lock  , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);
 320 }
 321 
 322 GCMutexLocker::GCMutexLocker(Monitor * mutex) {
 323   if (SafepointSynchronize::is_at_safepoint()) {
 324     _locked = false;
 325   } else {
 326     _mutex = mutex;
 327     _locked = true;
 328     _mutex->lock();
 329   }
 330 }
 331 
 332 // Print all mutexes/monitors that are currently owned by a thread; called
 333 // by fatal error handler.
 334 void print_owned_locks_on_error(outputStream* st) {
 335   st->print("VM Mutex/Monitor currently owned by a thread: ");
 336   bool none = true;
 337   for (int i = 0; i < _num_mutex; i++) {
 338      // see if it has an owner
 339      if (_mutex_array[i]->owner() != NULL) {
 340        if (none) {
 341           // print format used by Mutex::print_on_error()
 342           st->print_cr(" ([mutex/lock_event])");
 343           none = false;
 344        }
 345        _mutex_array[i]->print_on_error(st);
 346        st->cr();
 347      }
 348   }
 349   if (none) st->print_cr("None");
 350 }