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